International Journal of Students Research in Technology & Management Vol 1(2), April 2013, pg 82-88
STRUCTURE AND TEXTURE SYNTHESIS Pragnesh Patel, Shailesh Gupta, Haider Zafar, Nilesh Deotale Computer Department, Mumbai University Lokmanya Tilak college of Engineering, Koparkhairne, Navi Mumbai. patelpragnesh85@gmail.com, shaileshgpt47@gmail.com, haiderzafar72@gmail.com
Abstract An approach for filling-in blocks of missing data in wireless image transmission is presented in this paper. When compression algorithms such as JPEG are used as part of the wireless transmission process, images are first tiled into blocks of 8x8 pixels. When such images are transmitted over fading channels, the effects of noise can destroy entire blocks of the image. Instead of using common retransmission query protocols, we aim to reconstruct the lost data using correlation between the lost block and its neighbours. If the lost block contained structure, it is reconstructed using an image inpainting algorithm, while texture synthesis is used for the textured blocks. The switch between the two schemes is done in a fully automatic fashion based on the surrounding available blocks. The performance of this method is tested for various images and combinations of lost blocks. Keywords - Restoration, interpolation, inpainting, filling-in, texture synthesis, JPEG, wireless transmission ,compression. I.
INTRODUCTION
General purpose images are most commonly compressed by lossy JPEG. JPEG divides the image into blocks of 8x8 pixels and calculates a two-dimensional (2-D) discrete cosine transform (DCT), followed by quantization and Huffman encoding; see [1]. In common wireless scenarios, the image is transmitted over the wireless channel block by block. Due to severe fading, we may lose an entire block, even several consecutive blocks of an image. In [2] the report that average packet loss rate in a wireless environment is 3.6% and occurs in a bursty fashion. In the worst case, a whole line of image blocks might be lost. Note that JPEG uses differential encoding for storing the average (dc) value of successive pixels. Hence, even if a single block is lost, the remaining blocks in that line (or reset interval) might be received without their correct average (dc) value. Two common techniques to make the transmission robust are forward error correction (FEC) and automatic retransmission query protocols (ARQ). Of these, FEC needs extra error correction packets to be transmitted. As noted in [3], ARQ lowers data transmission rates and can further increase the network congestion which initially induced the packet loss. Instead, we show that it is Possible to satisfactorily reconstruct the lost blocks by using the available information surrounding them this will result in an increase in bandwidth efficiency of the transmission. The basic idea is to first automatically classify the block as textured or structured (containing edges), and then fill-in the missing block with information propagated from the surrounding pixels. In the case of structured www.giapjournals.com
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blocks, the inpainting algorithm in [4] is used; while for textured regions we follow [5].2 We test the proposed scheme with a variety of images and simulated block losses. We also combine this approach with JPEG compression itself, where the encoder voluntarily skips blocks, and these are reconstructed at the decoder in the same fashion as in the wireless scenario. This process improves the compression ratio, at little or no quality degradation. II.
PROPOSED ALGORITHM
A. Image Transform Coding For JPEG Compression Algorithm. The Joint Photographic Expert Group (JPEG), Formed as a joint ISO and CCITT working committee, is focused exclusively on still image compression.JPEG is compression standard for still color image and gray-scale image, otherwise known as continuous-tone images. The JPEG compression scheme is lossy and utilizes forward discrete cosine transform, a uniform quantizer and entropy encoding. The DCT function removes data redundancy by transforming data from a spatial domain to a frequency domain: the quantizer quantizes DCT coefficients with weighting functions to generate quantized DCT coefficients optimized for human eye; and the entropy encoder minimizes the entropy of the quantized DCT coefficents. By this methodology, the reduction of a large volume of data to a smaller version is achived, discarding information that has little visual effect, and further compression of the data by takingadvantage of its spatial characteristics. B. The Discrete Cosine Transform(DCT) DCT is a mathematical operation closely related to Fourier Transform. In the Spatial domain the image requires lots if data points. Once image is converted to frequency domain using Fourier transform family, only a few points are required to present the same image, because image contains only a few frequency components. This technique can be applied to a color image. A color image is composed of pixels. These pixels have RGB color values, each with its x and y coordinates using 8X8 or 16X16matrix for each primary color. When considered over an 8X8 matrix of 64 values, each with x and y coordinates, we have a three dimensional representation of pixel called a spatial representation or spatial domain. Compression algorithm, the input image is subdivided into 8-by-8 or 16-by-16 non-overlapping blocks, and the two-dimensional DCT is calculated for each block. The DCT coefficients are then quantized, coded, and transmitted. The JPEG receiver decodes the quantized DCT coefficients, calculates the inverse two-dimensional DCT of each block, and then puts the blocks back unruffled into a single image. For typical images, many of the DCT coefficients have values near to zero; these coefficients can be cast-off without seriously disturbing the quality of the reconstructed image. A two dimensional DCT of an M by N matrix A is defined as given in eqn(2):
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2
cos
1
2
2
1 2
, 0
0
1 1 …. (2)
Where, 1 √ 2
0
,1 1 √
2
,
1 ,
0
,1
1
The DCT is invertible transformation and its inverse is given as:
2
cos
1
2
2
1 2
, 0
1
0
1
Where, 1 √ 2
0
,1 1 √
2
,
,1
1 ,
0 1
The DCT based encoder can be thought of as basically compression of a stream of 8 X 8 blocks of image sections. Each 8 X 8 block makes its way through each processing step, and produces Output in compressed form into the data stream. Because nearby image pixels are highly associated, the ‘forward’ DCT (FDCT) processing step lays the foundation for accomplishing data compression by concentrating most of the signal in the lower spatial frequencies. For atypical 8 X 8 sample block from a classic source image, most of the spatial frequencies have zero or near-zero amplitude and
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need not be encoded. In principle, the DCT presents no loss to the source image samples; it purely transforms them to a realm in which they can be more competently encoded. After output from the FDCT, each of the 64 DCT coefficients are uniformly quantized in aggregation with a carefully designed 64 – element Quantization Table. At the decoder, the quantized values are multiplied by the respective QT elements to recover the original values. After quantization, all of the quantized coefficients are well-arranged into the “zig-zag� sequence. This arrangement helps to facilitate entropy encoding by assigning low-frequency non-zero coefficients before high-frequency coefficients. The DC coefficient, which contains a significant fraction of the complete image energy, is differentially encoded. The reconstructions of lost blocks are in three steps:1. Classify lost blocks into two types i.e. texture and structure 2. Synthesize blocks which were classified as texture ; 3. To fill in blocks which were classified as structure C. Block Classification:The first step in image reconstruction is to classify the errors i.e. whether they are texture or structure. This process is done after receiving the image on receiver side. After receiving the image receiver checks the pixels surrounding the lost block. For doing this we will use the method given by[11] . To determine whether the image contains texture or not we just define some threshold value to the local surrounding pixels. For assigning threshold values to the pixels we use method given by as follows
2 Where UB and LB are upper and lower threshold value s. The threshold value vary between 0 and 1.We have used UB=0.16 and LB=0.04. as suggested in . The above method is applied for each 8x8 block in the immediate neighborhood of the lost block. If the block contains even a single structure then we have to consider the structure first, also there is some limitation in algorithm stated in [11] To overcome this limitation we will divide the image in 8 neighbor of 8x8 block and calculate the difference of them if 4 continuous difference is less than threshold value we will assign that pixel as structure. D. Texture synthesis procedure Most schemes reported in the literature deal with image transmission in error-prone environments using a combination of source and channel coding. we describe a packetization scheme in which the DCT coefficients array generated by JPEG is grouped such that bursty (consecutive) packet loss during transmission is scattered into a pseudo-random loss in the image domain (i.e., consecutive blocks are rarely lost in the image domain). The ensuing reconstruction scheme benefits because,
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most frequency components can be recovered from adjacent blocks. However, large bursts may cause the errors to cluster in the image, and reconstruction suffers. It should be noted that the packetization scheme proposed in , when used with the reconstruction scheme described in our paper, is expected to further improve on the results reported here, and provide satisfactory reconstruction results even for very large bursts. We also note that interleaving the image data before packetization avoids loss of contiguous areas in an image, facilitating reconstruction. This paper demonstrates reconstruction in the transform domain by expressing the lost data as a linear combination of blocks in the 4-neighborhood of the lost block. Four optimal weights (coefficients) need to be calculated per block based on combinations of available adjacent blocks. These weights, which result in a 10% space overhead, are used later in reconstruction. Strong diagonal edges are not well reconstructed by this method. Additional work on the reconstruction of missing data in block-based compression schemes is reported in, where the DCT coefficients of a missing block are interpolated from those with the same position in the neighboring blocks. The novelty of our proposed scheme is in the separation of the lost blocks into different classes, followed by the use of state-of-the-art image filling-in algorithms for textured and structured regions. This is done in a complete automatic fashion and without any side information.
A. Image Inpainting Structure in an image can be an edge between two regions or the deterministic change in color or gray level. When the structure is classified in block classification then that pixel is replaced by digital image in painting method given by [4] In this method let Ω be the region to be filled and ∂Ω be its boundary. The basic idea is to smoothly distribute the information around Ω. Both the gray value and the isophote direction are distributed within the boundary. Let the image is denoted by I then we can distribute the values by using the partial differential equation given as ∆I . Where ,∆ and
are gradiant ,laplacian and orthogonal gradiant(isophote direction) respectively.
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Fig. 2 Image correction process III.
CONCLUSION AND FUTUREDIRECTIONS
We have proposed a new technique for the filling-in of missing blocks in wireless transmission of JPEG (or block based) compressed images. We have shown that as long as the features in the image are not completely lost, they can be satisfactorily reconstructed using a combination of computationally efficient image inpainting and texture synthesis algorithms. This eliminates the need for retransmission of lost blocks. When image resolution is increased, the quality of reconstruction improves & retransmission request is rarely required. We have tried to use image dependent information i.e. texture and structure to enhance the performance of JPEG. The compression ratio can be further increased by finding better masks by providing more image information. Missing blocks in the different channels need not be in the same image used in block classification & reconstruction .Adding this to current neighbouring information used is expected to improve even further the quality of results.
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REFERENCES [1] E. Chang, “An image coding and reconstruction scheme for mobile computing,” in Proc. 5th IDMS, Oslo, Norway, Sept. 1998, pp. 137–148. [2] S. S. Hemami, “Digital image coding for robust multimedia transmission,” in Proc. Symp. Multimedia Communications and Video Coding,New York, 1995. [3] M. Bertalmio, G. Sapiro, V. Caselles, and C. Ballester, “Image inpainting,” in Computer Graphics (SIGGRAPH 2000), July 2000, pp. 417–424. [4] A. A. Efros and T. K. Leung, “Texture synthesis by nonparametric sampling,” in IEEE Int. Conf. Computer Vision, Corfu, Greece, Sept. 1999,pp. 1033–1038. [5] C. Ballester, M. Bertalmio, V. Caselles, G. Sapiro, and J. Verdera, “Filling-in by joint interpolation of vector fields and gray levels,” IEEETrans. Image Processing, to be published. [6] T. Chan and J. Shen, “Mathematical models for local deterministic inpaintings,” UCLA CAM Rep., Mar. 2000. [7] D. Heeger and J. Bergen, “Pyramid based texture analysis/synthesis,” in Proc. SIGGRAPH 1995, July 1995, pp. 229–238. [8] S. Masnou and J. Morel, “Level-lines based disocclusion,” in IEEE Int. Conf. Image Processing, Oct. 1998.
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CYBER SECURITY Mandar Tawde, Pooja Singh, Maithili Sawant, Girish Nair Information Technology, Government Polytechnic Mumbai 49, Kherwadi Ali Yawar Jung Marg, Bandra (E), Mumbai-400051, India mandar258@gmail.com, maithilisawant229@gmail.com
Abstract This document gives information about Hacking. Some Types of hacking, some tools of hacking and some preventive measures in order to stop hacking. It will help every computer user for the security of his system. As hacking is very upcoming and serious problem for many fields, the study of cyber security is important. Keywords - The best way of offending is defending I.
WHY HAVE WE OPT CYBER SECURITY ?
Hacking is hot and rapid growing national problem for which the market may fail to make a solution because individuals often select less than optimal security levels in a world of positive transaction cost. II. SCANDALOUS HACKINGS To show the seriousness of hacking we have included some very scandalous hacking incidences. A. 1960s
The Dawn of Hacking The advent of 1st computer hacking emerged at MIT. They were the group of people, who forcefully entered into model train group and began to hack the electrical trains, tracks and switches to make them perform faster and differently. But few due to their curiosity became typical hacker. B. 1995
The Mitnick Takedown Serial cyber trespasser Kevin Mitnick is captured by federal agents and charged with stealing 20,000 credit card numbers. C. 1998
The Cult of Hacking and the Israeli Connection The hacking group Cult of the Dead Cow releases its Trojan horse program, Back Orifice—a powerful hacking tool--at Def. Con. Once a hacker installs the Trojan horse on a machine running Windows 95 or Windows 98, the program allows unauthorized remote access of the machine. D. 1999
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Mellisa virus hit Microsoft and other big company which lead them to temporarily terminate their email systems. III. WHAT IS CYBER SECURITY? Cyber security is the body of technologies, processes and practices designed to protect networks, computers, programs and data from attack, damage or unauthorized access. IV. HACKING • Hacking is a process to bypass the security mechanisms of an information system or network. •
In common usage, hacker is a generic term for a computer criminal, often with a specific specialty in computer intrusion. While other definitions peculiar to the computer enthusiast community exist, they are rarely used in mainstream context.
•
Hacking is an unauthorized use of computer and network resources. (The term "hacker" originally meant a very gifted programmer. In recent years though, with easier access to multiple systems, it now has negative implications.)
V.
TYPES OF HACKING
Fig 1 Security Incidents reported during 2009 A. Computer Hacking
Computer hacking is the practice of modifying computer hardware and software to accomplish a goal outside of the creator’s original purpose.
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Types of Computer Hackers-There are two types of computer hackers. •
Attitude
•
Purpose
B. Password Hacking
•
Password hacking is the process of recovering secret password from data that has been stored in or transmitted by a computer system.
•
Password hacking can help a legitimate user retrieve a forgotten password.
•
System administrators may use password hacking as a preventive tactic, to check for easily hacked passwords in order to modify them for increased security.
•
Unauthorized users hack passwords to gain access to a secure system.
C. Phishing
•
Its art of managing the victim to access a duplicate web pages
•
Phishing is a way of attempting to acquire information such as usernames, passwords, and credit card details by masquerading as a trustworthy entity in an electronic communication. Phishing is typically carried out by e-mail spoofing or instant messaging and it often directs users to enter details at a fake website whose look and feel are almost identical to the legitimate one.
•
Case study: eBay, yahoo.
D. Virus and worms
Viruses and worms are self-replicating programs or code fragments that attach themselves to other programs (viruses) or machines (worms). Both viruses and worms attempt to shut down networks by flooding them with massive amounts of bogus traffic, usually through email. VI.
TOOLS OF HACKING
A. RAT
•
RAT is a remote administration tool or Remote Access Trojan
•
It gives the admin privileges to the attacker
B. NetCat
•
Netcat has been dubbed the network Swiss army knife.
•
It is a simple Unix utility which reads and writes data across network connections, using TCP or UDP protocol
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•
Netcat is designed to be a dependable “back-end” device that can be used directly or easily driven by other programs and scripts. At the same time, it is a feature-rich network debugging and investigation tool; since it can produce almost any kind of correlation you would need and has a number of built-in capabilities.
•
Its list of features includes port scanning, transferring files, and port listening, and it can be used as a backdoor.
C. Ethereal
•
Ethereal is a free network protocol analyzer for UNIX and Windows.
•
Ethereal has several powerful features, including a rich display filter language and the ability to view the reconstructed stream of a TCP session.
D. NetBus
Netbus is programmed software which requires, a device which looks like this.
This devise is attached at the ports. This method is used for getting passwords, banking details, etc. •
In 1999, Net Bus was used to plant child pornography on the work computer of a law scholar at Lund University. The 3,500 images were discovered by system administrators, and the law scholar was assumed to have downloaded them knowingly. He lost his research position at the faculty, and following the publication of his name fled the country and had to seek professional medical care to cope with the stress. He was acquitted from criminal charges in late 2004, as a court found that Net Bus had been used to control his computer.
VII.
PREVENTIVE MEASURES.
To Prevent Hacking we should use:A. Anti-viruses
In order to damage our security system hackers generally try to send malwares, spam wares, etc. Antivirus is best tool to defend their access in our system. B. Eraser
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Eraser is an advanced security tool (for Windows), which allows you to completely remove sensitive data from your hard drive by overwriting it several times with carefully selected patterns. Works with Windows 95, 98, ME, NT, 2000, XP and DOS. Eraser is free software and its source code is released under GNU General Public License. C. Firewall
One way of being warned that malware has infected your machine is by using a software firewall (this also works well for viruses too). When a software firewall catches a program trying to make a connection, it will alert you, give you the name of the program, and ask if you want to block it from the Internet. VIII.
INFERENCE
If with a few advancements in the way we are using the internet we can avoid a big threat and make web a safer place. Some of them would be •
Using a good proxy server
•
Using vulnerability testers like nmap
•
Limiting the number of open ports
IX.
ACKNOWLEDGMENT
Cyber security has become an important part of our life. We have nurtured it from last days and while doing so we received in addition the compliments a lot of suggesting from publisher, authors, and professors. REFERENCES [1] Vaidihi and Gaurav “Hacker5”ed.2nd. [2] Ankit Fadiya-“Ethical hacking” ed.2d. [3] The google website. www.google.org [4] The Wikipedia website. www.wikipedia.org
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BRAIN GATE Shruti Kotian, Sonal Karkhanis, Shivang Menon Department of Computer Science, SIES GST, Nerul, Navi Mumbai, India shrutik04@hotmail.com
Abstract As the power of modern computers grows alongside our understanding of the human brain, we move closer to making some pretty spectacular science fiction into reality. Consider the potential to manipulate computers or machinery with nothing more than a thought! Thousands of people around the world suffer from paralysis and loss of other bodily movement, rendering them dependent on others to perform even the most basic tasks. The mind-to-movement system that allows a quadriplegic man to control a computer using only his thoughts is a scientific milestone. This is the BRAIN GATE system. Brain gate system is based on ‘Cyber kinetics’ platform technology to- sense, transmit, analyze and apply the language of neurons. A computer chip, which is implanted into the brain, monitors brain activity in the patient and converts the intention of the user into computer commands. It would be a huge therapeutic application for people who have seizures, which leads to the idea of a ‘pacemaker for the brain’. Keywords: BCI (Brain-Computer Interface), motor cortex. I.
INTRODUCTION
The principle of operation of the brain gate neural interface system is that with intact brain function, neutral signals are generated even though they are not sent to the arms, hands and legs. These signals are interpreted by the system and a cursor is shown to the user on a computer screen that provides an alternate “Brain Gate pathway”. The user can use that cursor to control the computer, just as a mouse is used. A brain-computer interface (BCI) which is a direct communication pathway between a human (brain cell culture) and an external device, serves this purpose. II.
WORKING
The Brain Gate device consists of a tiny chip that is surgically implanted in the brain's motor cortex. The chip can read signals from the motor cortex, send that information to a computer via connected wires, and translate it to control the movement of a computer cursor or a robotic arm. However, because movement carries a variety of information such as velocity, direction, acceleration and as the BCI is only www.giapjournals.com
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reading signals from a small sample of those cells, the initial control of a robotic hand may not be as smooth as the natural movement of a real hand. But with practice, the user can refine those movements using signals from only that sample of cells. Advantages: •
It’s potential to interface with a computer without weeks or months of training.
•
It’s potential to be used in an interactive environment, where the user's ability to operate the device is not affected by their speech, eye movements or ambient noise.
•
The ability to provide significantly more usefulness and utility than other approaches by connecting directly to the part of the brain that controls hand movement and gestures.
Disadvantages: •
The switches must be frequently adjusted which is a time consuming process. As the device is perfected this will not been issue.
•
There is also a worry that devices such as this will “normalize” society.
•
The Brain Gate Neural Interface System has not been approved by the FDA, but has been approved for IDE status, which means that it has been approved for pre-market clinical trials.
• III.
Limitation in information transform rate. The latest technology is 20 bits/min. CONCLUSION
Medical cures are unavailable for many forms of neural and muscular paralysis. Thus, the idea of moving robots or prosthetic devices not by manual control, but by mere “thinking” is a major scientific milestone in the history of mankind! IV.
CURRENT WORK PROGRESS Brain Gate is currently recruiting patients with a range of neuromuscular and neuron-degenerative conditions for pilot clinical trials being conducted under an Investigational Device Exemption (IDE) in the United States. Cyber kinetics hopes to refine the Brain Gate in the next two years to develop a wireless device doesn’t have a plug, making it safer and less visible. And once the basics of brain mapping are worked out, there is potential for a wide variety of further applications.
REFERENCES
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[1] Levine, SP; Huggins, JE; Bement, SL; Kushwaha, RK; Schuh, LA; Rohde, MM; Passaro, EA; Ross, DA et al. (2000). "A direct brain interface based on event-related potentials". IEEE transactions on rehabilitation engineering: a publication of the IEEE Engineering in Medicine and Biology Society. [2] Miguel Nicolelis et al. (2001) Duke Neurobiologist has developed system that allows monkeys to control robot arms via brain signals. [3] http:// www.howstuffworks.com [4] http:// www.wikipedia.org
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SPEED CONTROL MECHANISM USING TERRAIN DETECTION Ankit Nanavaty, Ruchi Patel, Ankit Kandoi Dept. of Computer, MCT’s Rajiv Gandhi Institute of Technology, Mumbai, India ankit.n24@gmail.com, ruchi_spatel@yahoo.com, ankitkandoi@gmail.com
Abstract Information of texture to distinguish between the types of terrains in the environment are not defined by clear boundaries. In this paper we illustrate that an image consists of a composite texture of regions. Using Image Processing Algorithms, the type of the terrain is identified, and accordingly the appropriate velocity of the robot is derived, so that the robot can traverse over that particular terrain. It’s a real time process, and the speed of the robot changes with a change in the terrain in the environment. A video camera will be mounted on the robot, with a similar perspective to the driver, which takes the video of the road, with different classes of textures when the car is in motion. These textures (loose stones, grass, ground, concrete, asphalt, slopes) will then be processed using Image Processing Algorithms. Based on the results obtained after applying the algorithms, the velocity estimations are done and the speed of the robot changes accordingly. Keywords- Wavelet transform; WCF; FIS I. INTRODUCTION Navigation with vehicles in unknown environments is an easy task for humans, but very difficult for robots [3]. For autonomous navigation in outdoor terrains, the robot must be endowed with the ability to interpret data acquired from its environment so as to plan and follow trajectories from its current location to the desired location, considering the features of the terrains [3]. Most autonomous navigation works have focused on the problem of recognition and avoidance of obstacles; however, so far, almost no attention has been placed on the recognition of terrains' textures and irregularities, and how they accept the performance and safety of robots during navigation. Autonomous off-road robots will be employed in military operations, and also in civilian applications such as widearea environment monitoring, disaster recovering, search-and-rescue activities, as well as planetary exploration. [1]. There is a strong push in the Army to move towards autonomous and semi-autonomous vehicles to perform tasks which may be too cumbersome or dangerous for human driven vehicles to perform. Unmanned ground vehicles (UGVs) can potentially be used to find and disarm improvised explosive devices (IEDs) without risking the lives of soldiers [2].
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The right navigating velocity regarding the terrain features is a requisite to keep robots away from risks of falling and sliding due to surface slopes or smash textures, the vehicle velocity must be updated according to the terrain features in order to guarantee robots safe navigation. For wheeled-robots navigation on different terrains, it is necessary to have required information about the surface features [3]. One of those features on which this work focuses is the surface roughness on which the vehicle is moving. The terrain is the principle source of chassis excitation in off-road vehicles and the control of the vehicle is dependent on effectively characterizing the terrain slope, roughness, and surface condition [2]. The robot's velocity during real navigation depends on the terrain roughness; moreover, the robot integrity depends on the right velocity of the robot while navigating through terrain. The information of environment needs to be quickly and accurately processed by the robot's navigation systems for a right displacing. The velocity setting must be performed remotely, i.e. the robot must detect and classify soft irregularities and textures before the robot passes on them, so that the robot disposes enough time to react and set its velocity according to the terrains' characteristics [3]. On the other hand, by extending the robots' abilities to recognize the terrains' features and then, accordingly, update the velocity while navigating, the usage of the robots' energy and computing resources would improve as well as the autonomy would be strengthen. During navigation, the robot can move on irregularities under the following criteria; if irregularities are soft (slopes with inclination less than or equal to 15 degrees), then the robot can move over them; otherwise, the non-soft irregularities (slopes with inclination bigger than 15 degrees) are considered as slopes, slope detection algorithms need to be applied and velocity of the robot must be adjusted accordingly. II.
PROPOSED SPEED CONTROL SYSTEM
A. Algorithm
•
A wireless camera is mounted on the robot (vehicle) which captures the video and transmits it the Processing end (PC).
•
This video is converted into image frames for further processing.
•
The first frame is taken and the Texture Segmentation Algorithm (Texture Segmentation using Wavelet Transform) is applied. Thus we obtain various segments of the processed image.
•
The Wavelet Co-occurrence Feature (WCF) values of each segment in the image, is calculated. WCF values give the features of the segments such as contrast, cluster, shade and cluster prominence, brightness and the relationship between them [5]. According to these WCF values, the speed of the robot is adjusted.
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Figure 1. Flow of the Speed Control System
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•
If the WCF value is greater than the maximum threshold, it implies maximum roughness, and thus we vary the robot speed to the minimum value for safe navigation. If the WCF value is less than the minimum threshold, it implies minimum roughness, and thus we vary the robot speed to the maximum value for safe navigation.
•
Hence, the robot motion takes place with the calculated speed, where the change in speed is calculated considering the difference in textures of the terrain.
•
This process is continued till all the frames are processed and the speed of the robot is detected for the whole path. II.
DISCRETE WAVELET TRANSFORM
A. Definition
Discrete Wavelet Transform (DWT) is performed in the frequency domain, where the input image is decomposed to different frequency levels using the Discrete Wavelet Frames (DWF). Few statistical methods have been proposed in the past for texture analysis. Inherent disadvantages with those approaches, such as increased computational cost and irreversibility, can be eliminated using the wavelet transform [4]. Wavelets are functions generated from one single function W by dilations and translations. The basic idea of the wavelet transform is to represent any arbitrary function as a superposition of wavelets [5]. Any such superposition decomposes the given function into different scale levels where each level is further decomposed with a resolution adapted to that level. The discrete wavelet transform (DWT) is identical to a hierarchical sub band system where the sub-bands are logarithmically spaced in frequency and represent octave-band decomposition. By applying DWT, the image is actually divided i.e., decomposed into four sub-bands and critically sub-sampled [5]. These four sub bands arise from separate applications of vertical and horizontal filters. The sub-bands labeled LH1, HL1 and HH1 represent the finest scale wavelet coefficients i.e., detail images while the sub-band LL1 corresponds to coarse level coefficients i.e., approximation image. To obtain the next coarse level of wavelet coefficients, the sub-band LL1 alone is
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Figure 2. Discrete Wavelet Transform further decomposed and critically sampled. This results in two-level wavelet decomposition. Similarly, to obtain further decomposition, LL2 will be used. This process continues until some final scale is reached. The values or transformed coefficients in approximation and detail images (sub-band images) are the essential features, which are as useful for texture discrimination and segmentation. Since textures, either micro or macro, have non-uniform gray level variations, they are statistically characterized by the values in the DWT transformed sub band images or the features derived from these sub-band images or their combinations. In other words, the features derived from these approximation and detail sub-band images uniquely characterize a texture. The features obtained from these DWT transformed images give the segmented images. B. Advantages over Fourier Transform
Although the Fourier transform has been the mainstay of transform-based image processing since the late 1950s, a more recent transformation, called the wavelet transform, is now making it even easier to compress, transmit, and analyze many images. Unlike the Fourier transform, whose basis functions are sinusoids, wavelet transforms are based on small waves, called wavelets, of varying frequency and limited duration [6]. A wavelet is a waveform that is bounded in both frequency and duration [8]. This allows them to provide the equivalent of a musical score for an image, revealing not only what notes (or frequencies) to play but also when to play them. Conventional Fourier transforms, on the other hand, provide only notes or frequency information; temporal information is lost in the transformation process. Most real world signals (such as music or images) have a finite duration and abrupt changes in frequency. This makes wavelet transform more efficient [8]. III.
TEXTURE SEGMENTATION
The study of terrain vehicle interaction has been a topic which has been researched for quite some time. Researchers have used it to refer to understanding the mechanical properties of the terrain called terramechanics. The terrain segmentation problem is to assign a class label to each pixel of an image based on the properties of the pixel and its relationship with its neighbourhoods [10]. Determining how the terrain properties affect a vehicle’s ability to traverse it, which has also been referred to as traffic ability. It has also been used to describe the process of classifying the type of terrain (i.e. sand, dirt, gravel). The segmentation process is a joint detection and estimation of the class labels and shapes of the regions with homogeneous statistical properties [10]. One will also see the term terrain segmentation used for larger scales than relevant for vehicle dynamic studies, such as in geological surveys or aerial vehicle mapping. Many of these works use Digital Elevation Models (DEM) to represent the terrain. Thus, the literature
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presented here will include terrain segmentation as it relates to mechanical properties, small ground robots, and larger ground vehicles. Here, texture mosaic images of size N x N are considered [4]. The analysis is carried out by considering sub images (i.e., block) of size 32 x 32. Each 32 x 32 sub-image, taken from top left corner of the original image, is decomposed using one level DWT and co-occurrence matrices (C) are derived for sub-image. Fig. 2 (a) shows the level 1 decomposition (i.e., LL1, LL2, LL3, LL4) and fig. 2 (b) shows the level 2 decomposition with detail sub-bands (i.e., LL2, LH2, HL2 & HH2 sub-bands) of wavelet decomposed sub-image. Then, from these co-occurrence matrices (C), significant WCFs, such as contrast, cluster shade and cluster prominence, are computed using formulae given, as texture features [3]. In our implementation, the contrast feature values, calculated over all the blocks, are subjected to linear normalization in the scale of 0–255, while the cluster shade and cluster prominence features, which found to have very large dynamic ranges, are subjected to logarithmic normalization in the scale of 0–255 for computation [5]. A. Segmentation Algorithm
Input : Texture mosaic image of size N x N. Output: Texture segmented image. Step 1. Read the texture mosaic image. Step 2. Obtain 32 x 32 sub-image blocks, starting from the top left corner. Step 3. Decompose sub-image blocks using 2-D DWT. Step 4. Derive co-occurrence matrices (C) for original image, and
detail
sub-bands
of
DWT
decomposed sub image blocks. Step 5. Calculate WCFs such as contrast, cluster shade and
cluster prominence from co- occurrence
matrices. Step 6. Calculate the difference between sums of WCFs of
adjacent
sub-image
blocks.
This
results in segmentation band. Step 7. Apply disk filtering and thresholding techniques to remove noise like artifacts if any in the
segmentation band.
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Figure 3. Flow Chart of Texture Segmentation Algorithm Step 8. Apply skeleton extraction algorithm to get thinned or segmented line of one pixel thickness.
Fig. 3 shows the Flowchart of the Texture Segmentation Algorithm. The texture segmentation is carried out by comparing the normalized co-occurrence features of discrete wavelet transformed adjacent but overlapping 32 x 32 sub-image blocks, both horizontally and vertically [4]. Each successive block is differ from the previous one in its spatial location by one column or one row, depending on whether the successive block is taken in horizontal or vertical direction, respectively. Here, the sum of the above normalized features of one block is compared with the corresponding sum of features derived from the next block. The difference in feature values is less when successive blocks belong to the same texture region and it increases in the texture border region while it is high when the successive blocks are from two different texture regions. By carrying out the above block by block feature comparison both in horizontal and vertical directions; a segmentation band is formed across the texture boundaries [9]. When the difference in feature values within the same texture region is high, noise like artifacts or spurious spots appear in the segmented image. This spurious spots are removed by applying disk filtering and thresholding techniques (i.e., post processing). Then, the post processed segmented band is thinned using skeleton extraction algorithm to get segmented line of one pixel thickness [9]. The thinned result gives the line of demarcation among the different textures present in the image i.e., thinned lines are exactly aligned with texture boundaries. B. Advantages over Other Algorithms
More recently, methods based on multi-resolution or multi-channel analysis, such as Gabor filters and wavelet transform,
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have received a lot of attention. But, the outputs of Gabor filter banks are not mutually orthogonal, which may result in a significant correlation between texture features [5]. Finally, these transformations are usually not reversible, which limits their applicability for texture synthesis. Most of these problems can be avoided if one uses the wavelet transform, which provides a precise and unifying frame work for the analysis and characterization of a signal at different scales (e.g., Unser, 1995). Another advantage of wavelet transform over Gabor filter is that the low pass and high pass filters used in the wavelet transform remain the same between two consecutive scales while the Gabor approach requires filters of different parameters. In other words, Gabor filters require proper tuning of filter parameters at different scales. One advantage of the wavelet transform over the histogram processing is that in many cases, a large number of the detail coefficients turn out to be very small in magnitude [7]. Truncating these small coefficients from the representation introduces only small errors in the reconstructed signal. We can approximate the original data distribution effectively by keeping only the most significant coefficients [7]. IV.
VELOCITY ESTIMATION
It is proposed to imitate the human perception by employing an approach for velocity updating. Hence, to imitate the human experience for terrain recognition and the corresponding velocity adjustments when driving, the choice of an adequate method for recognizing the surface average appearance, without lost in unnecessary terrain details, is clever for outdoors navigation. In Earth exploration missions, where human life could be in danger, autonomous rovers are required for explosive landmines search, deep sea exploration, or to determine the eruption risk when exploring active volcano craters, as well others [2]. In these dangerous circumstances, the high autonomy of robots strengthens the robotic support to human safety. On the other hand, by extending the robots' abilities to recognize the terrains' features and then, accordingly, update the velocity while navigating, the usage of the robots' energy and computing resources would improve as well as the autonomy would be strengthen.
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ANALYZING THE RESULTS
Figure 4. Fuzzy Inference System for Speed Control Mechanism The Fig 4. shows the Fuzzy Inference System for the system Speed Control Mechanism Using Terrain Detection. As shown, it has one input, namely texture and one output, namely speed. The mamdani model is used to create the FIS.
Figure 5. Input Membership function plot- Texture Fig. 5 shows the input (texture) membership function plot with the descriptors as smooth, rough and very_rough. The values of texture are based on the sum of the WCF values calculated and it ranges from 2 to 3. The range of values for the three descriptors is as shown in the fig. 5.
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Figure 6. Output Membership function plot- Speed Fig. 6 shows the output (speed) membership function plot with the descriptors stop, medium and high. The range of values that speed can take is from 0 rpm to 100 rpm. The range of values that the three descriptors can take is as shown in the fig. 6. Fuzzy If then Rules: 1. If (Texture is smooth) then (Speed is high) (1) 2. If (Texture is rough) then (Speed is medium) (1) 3. If (Texture is very_rough) then (Speed is stop) (1) VI.
•
CONCLUSIONS In this project, for texture segmentation, the concept of discrete wavelet transform is presented for applying to textured images for decomposing them into detail and approximation regions.
•
Co-occurrence features, computed out of the wavelet decomposed images, are used for texture segmentation.
•
The idea behind this proposed method is to exhibit the usage of co-occurrence features computed from discrete wavelet transformed images (i.e., WCF) for texture segmentation.
•
The features are approximately the same when the windows or sub images considered are from the same texture and different if they are from different textures.
•
Varieties of textures, collected from standard album, are stitched to form target images which are used for experimentation and it is found that the proposed method yield better results than the texture spectrum method, a single resolution technique
•
Appearance-Based recognition algorithms successfully classify terrain textures by regarding the average appearance.
•
The algorithms are computationally inexpensive and easy implementation.
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•
The low computational cost to process the information acquired from the environment allows establishing that a car, at a certain speed, can have enough time to react to the roughness changes of the terrain.
•
The wavelet based algorithm for wheeled-robots allows a meta-classification of textures and soft irregularities used for the terrains' roughness recognition.
•
The wavelet based algorithm allows velocity updating by outdoor terrains navigation.
•
The average appearance of the terrains' textures, according to experimental results, is the requisite for velocity updating purpose on outdoor terrains navigation.
•
By applying robot velocity updating by regarding the terrains' roughness, the experimental results show the precision improvement.
•
Thus, by using the wavelet based texture recognition method and slope detection, we can ensure safer navigation of the robots on an unknown terrain.
VII. ACKNOWLEDGMENT
We would like to express our gratitude towards Dr. Udhav Bhosle, Principle, Rajiv Gandhi Institute of Technology, Prof. S.B. Wankhade, HoD, Computer Engineering for providing us with the wonderful opportunity. We are very grateful towards Mr. Swapnil Gharat, our guide and mentor, for his valuable suggestions and input towards the betterment of this paper. REFERENCES [1]
“Reactive speed control system based on terrain roughness detection” by Mattia Castelnovi, Laboratorium Dist., University of Genova; Ronald Arkin, College of Computing Georgia Institute of Technology; Thomas R Collins, School of ECE/GTRI, Georgia Institute of Technology
[2]
“Terrain characterization and roughness estimation for simulation and control of unmanned ground vehicles” by Jeremy James Dawkins -December 12, 2011.
[3]
“Wheeled-robot’s velocity updating and odometry based localization by navigating on outdoor terrains” by M. en C. Farid García Lamont. Thesis advisor: José Matías Alvarado MentadoNovember 2010.
[4]
“Unsupervised texture segmentation using discrete wavelet frames” by S. Liapis, N. Alvertos, and G. Tziritas Institute of Computer Science - FORTH, and, Department of Computer Science, University of Crete, P.O. Box 1470, Heraklion, Greece.
[5]
“Texture segmentation using wavelet transform” by S. Arivazhagan, Department of Electronics and Communication Engineering, Mepco Schlenk Engineering College, Amathur (P.O.), Sivakasi 626 005, Tamil Nadu, India; L. Ganesan, Department of Electronics and Communication
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Engineering, Mepco Schlenk Engineering College, Amathur (P.O.), Sivakasi 626 005, Tamil Nadu, India, 4 February 2003; received in revised form 31 July 2003. [6]
“Digital image processing”, Second Edition by Rafael C. Gonzalez and Richard E. Woods.
[7]
“Wavelet-based histograms for selectivity estimation” by Yossi Matias, Department of Computer Science Tel Aviv University, Israel: Jerey Scott Vittery Department of Computer Science, Duke University; Min Wangz Department of Computer Science,Duke University.
[8]
“Design of feature extraction in content based image retrieval (CBIR) using color and texture”, Swati V. Sakhare & Vrushali G. Nasre Dept. of Electronics Engg., Bapurao Deshmukh College of Engg., Sevagram, Wardha (India).
[9]
“Wavelet based image segmentation”, Andrea Gavlasov´a, Aleˇs Proch´azka, and Martina Mudrov´a Institute of Chemical Technology, Department of Computing and Control Engineering.
[10]
“Image segmentation using wavelet domain classification”, Hyeokho Choi and Richard Baraniuk, Department of Electrical and Computer Engineering, Rice University, Houston, Tx77005, USA.
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WIRELESS EQUIPMENT CONTROL Sarang Sutavani, Pratik Borhade, RohitChoudhary, Milan Bhanushali Electronics Department, Shah & Anchor Kutchhi Engineering College, Mumbai, India sutavanisarang@gmail.com Abstract This paper aims at presenting the concept of wireless equipment control using microcontroller and ZigBee, the name of a specification for a suite of high level communication protocols using small, lowpower digital radios based on the IEEE 802.15.4-2006 standard for wireless personal area networks (WPANs), such as wireless headphones connecting with cell phones via short-range radio. The technology is intended to be simpler and less expensive than other WPANs, such as Bluetooth. ZigBee is targeted at radio-frequency (RF) applications that require a low data rate, long battery life, and secure networking. Keywords - ZigBee, AT89C51 Microcontroller, RX-434 radio receiver, TRX-434 radio transmitter, ULN 2003 relay driver, CD4519 multiplexer. I. INTRODUCTION Here is a microcontroller based wireless equipment controller that can switch on or off devices depending on the switch pressed by the user in the transmitter section. The devices can be controlled remotely from a certain distance having range up to few meters depending on the transmitter used. In the transmitter, an LCD module is used to show the device name which are currently on. The 8-bit AT89C51 microcontroller is the main controlling part of the transmitter section. It is connected to the LCD module, input switches and encoder. The device control program is stored in the memory of the microcontroller to control the devices as per the pressing of input switches. The RF transmitter module uses a digital modulation technique called ASK (Amplitude Shift Keying) or on-off keying. The radio receiver module receives the ASK signal from the transmitter. The decoder IC demodulates the received address and data bits. Concepts of wireless RF communication and automation with AT89C51 microcontroller are used here. Another transmitter and receiver module is designed using ZigBee technology for comparative study. In this module instead of AT89C51 microcontroller based receiver a ZigBee transmitter and receiver based equipment controller is designed, which is based on IEEE 802 standard for personal area networks and operates in 2.4GHz (ISM) radio bands. II. TRANSMITTER SECTION www.giapjournals.com
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Microcontroller is the heart of the circuit. The control logic can be implemented using an assembly language or high level C language. Both languages have their own advantages. Assembly language provides a high level of security but is difficult to implement logic. On the other hand, in C language implementation of logic becomes very simple but there is no sense of security.
The Encoder used here is HT12E IC. It is an 18-pin DIP package encoder IC that encodes 4-bit data and sends it to the TRX-434 transmitter module. In this project we have used a TRX-434 transmitter module. The TRX -434 RF transmitter module uses a digital modulation technique called ASK (Amplitude Shift Keying) or on-off keying. In this technique, whenever logic ‘1’ is to be sent, it is modulated with carrier signal (434 MHz). This modulated signal is then transmitted through the antenna. The microcontroller reads the input data from the switches and displays it on the LCD. One of the Ports provides as read data to the encoder IC HT12E. The microcontroller is programmed to control the input and output data. When the push button switches are open, logic ‘0’ is constantly fed to the respective port pins to the microcontroller. When any of the buttons is pressed, logic ‘1’ is fed to the respective port pin of the microcontroller. The device control program stored in the memory of the microcontroller activates and executes as per the functions defined in the program for respective input switches.Data inputs of HT12E are connected to the microcontroller. The encoder will send the serial stream of pulses containing the address and data to the data input pin of the TRX RF module.
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When a key is pressed it executes the device control program sub routine in the microcontroller and the program automatically sends the data to encoder IC HT12E. The encoder IC sends the data to (D in) of the RF transmitter module. The data is transmitted by the TRX- 434 module to receiver section through antenna. III. RECEIVER SECTION The receiver used here is Rx-434 receiver module.The RX-434 radio receiver module receives the ASK signal from TRX-434.The decoder used in this project is HT12D decoder IC.
The HT12D decoder demodulates the received address and data bits. The multiplexer IC used is CD4519. IC CD4519 is a quadruple two- input multiplexer that selects appropriate data bits to control the devices. The o/p current of the multiplexer and the minimum threshold current required for the relay circuit is different. Hence, we use a relay driver IC ULN2003.The ULN 2003 relay driver consists of seven npn Darlington pairs that feature high- voltage outputs with common cathode clamps diodes for switching the inductive loads. The collector 窶田urrent rating of a single Darlington pair is 500 mA. The RF receiver circuit (RX- 434) module can receive the signal transmitted by the transmitter from a distance of upto 9 meters (30 feet). The range can be increased up to 30 meters using a good antenna. D out pin of RX-434 module is connected to the decoder IC (HT12D). Decoder IC receives the address and data bits serially from the RF module. Decoder separates data and address from the received information. It accepts data only if thereceived address matches with the www.giapjournals.com
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assigned to the encoder address (HT12E). The HT12D decoder receives serial addresses and data from the encoder that are transmitted by a carrier signal over the RF medium. The decodercompares the serial input data three times continuously with its local address. If no error or unmatched codes are found, the input data codes are decoded and transferred to the output pins. The HT12D provides four latch type data pins whose data remains unchanged until new data is received. Data pins of the decoder send 4-bit data to CD4519 multiplexer IC. This IC CD4519 multiplexer provides four multiplexing circuits with common select inputs; each contains two inputs and one output. It may be used to selects 4-bit information from one of the two sources. The latched output data from the multiplexer is fed to the relay driver IC ULN2003, to control devices through relays. The system is small, simple and good for wireless equipment control. The devices can be controlled remotely from the distance up to 30 metres from the transmitter. The RF receiver module can receive the signal transmitted from a distance up to 9 metres(30feet). The range can be increased up to 30 metres using a good antenna. IV.
ZIG-BEE
ZigBee is a specification for a suite of high level communication protocols using small, low-power digital radios based on an IEEE 802 standard for personal area networks. ZigBee devices are often used in mesh network form to transmit data over longer distances, passing data through intermediate devices to reach more distant ones. This allows ZigBee networks to be formed ad-hoc, with no centralized control or highpower transmitter/receiver able to reach all of the devices. Any ZigBee device can be tasked with running the network. ZigBee is targeted at applications that require a low data rate, long battery life, and secure networking. ZigBee has a defined rate of 250 Kbit/s, best suited for periodic or intermittent data or a single signal transmission from a sensor or input device. Applications include wireless light switches, electrical meters with in-home-displays, traffic management systems, and other consumer and industrial equipment that requires short-range wireless transfer of data at relatively low rates. The technology defined by the ZigBee specification is intended to be simpler and less expensive than other WPANs, such as Bluetooth. The ZigBee network layer natively supports both star and tree typical networks, and generic mesh networks.ZigBee is notintended to support power line networking but to interface with it at least for smart metering and smart appliance purposes.
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Now as ZigBee is a transceiver, due to it’s use it is possible here to sendacknowledgement of reception ofthe signal from receiver to the transmitter. This will help us to determine whether the signal has reached the destination or not. With the help of this project we are comparing the two different systems, RF module and ZigBee, which can be used for the purpose of automation. V.
CONCLUSION
The system is small, simple and good for wireless equipment control. The microcontroller based equipment controller can switch on or off up to four devices. The devices can be controlled remotely from the distance up to 30 metres from the transmitter using a good antenna. With the use of ZigBee, we can send data up to 60 metres. ZigBee is a transceiver, so with a little more programming it is possible to receiver acknowledgement from the receiver. ZigBee is small, easy to use, efficient and consumes less power. So, it is perfect for the purpose of Automation. ACKNOLEDGEMENT We express our sincere thanks to our project guide Prof. Vidya Gogate for the help and facilities provided to us for our project. We also thank her for the motivation and guidance which enabled us to carry out our project work. We are thankful to her for monitoring our progress periodically and helping in solving our problems during the project work. We are also grateful to Prof. Uma Rao (Head of Department, Electronics) who provided us the opportunity to undertake the project. We would like to thank our Principal, Mr. Lande sir, for extending his support. We would also like to thank our parents for supporting us all the time during the project work. Last but not the least a vote of thanks to our colleagues and friends who supported us in the due course of our project. REFERENCES 1) The 8051 Microcontroller and Embedded Systems - by Muhammad Ali Mazidi, Janice Gillispie Mazidi 2) microcontroller51.blogspot.com 3) www.articlesnatch.com 4) www.alldatasheets.com
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5) www.efymag.com 6) Xbee Transreceiver Module - DigiMesh Inc. 7) Getting Started With XBee RF Module - a tutorial by Martin Hebel and George Bricker
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IMAGE ENCRYPTION USING ELLIPTIC CURVE CRYPTOGRAPHY Ashutosh Shukla1, Jay Shah2, Nikhil Prabhu3 Electronics & Telecommunication Engineering Department, 1,2 Thakur College of Engineering and Technology, Kandivali(E) , Mumbai-400101 3 St Francis Institute of Technology Borivali (W), Mumbai - 400103
Abstract This paper deals with encryption of image using Elliptic curve cryptography (ECC).Elliptic curve cryptography (ECC) is an approach to public key cryptography based on algebraic structure of elliptic curves over finite fields. Basic ElGamal elliptic curve encryption is used for encryption of the image. It brings about confidential, authentication and integrity in the exchange of data. The primary benefit promised by ECC is a smaller key size, reducing storage and transmission requirements. Keywords: ECC, domain parameter generation, key pair generation, ElGamal encryption algorithm.
I.
Introduction
The way to secure distributed multimedia applications is to encrypt multimedia data using public key cryptography algorithms. Cryptography means protecting private information against unauthorized access in that situation where it is difficult to provide physical security [1]. It is science of using mathematics to encrypt and decrypt data. The basic idea behind the cryptography is that “If it is not possible to prevent copying of information, it is better to prevent compression.” II.
Elliptic Curve Cryptography(ECC)
Public-key cryptography is based on the intractability of certain mathematical problems. Early publickey systems, such as the RSA algorithm, are secure assuming that it is difficult to factor a large integer composed of two or more large prime factors. For elliptic-curve-based protocols, it is assumed that finding the discrete logarithm of a random elliptic curve element with respect to a publicly-known base point is infeasible [2]. The size of the elliptic curve determines the difficulty of the problem. It is believed that the same level of security afforded by an RSA-based system with a large modulus can be achieved with a much smaller elliptic curve group. Using a small group reduces storage and transmission requirements. For current cryptographic purposes and elliptic curve is a plane curve which consists of the points satisfying the equation (1)
along with a distinguished point at infinity, denoted “∞”. (The coordinates here are to be chosen from a fixed finite field of characteristic not equal to 2 or 3, or the curve will be somewhat more complicated)[3].
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A. ECC Domain Parameters The public key cryptographic systems involve arithmetic operations on Elliptic curve over finite fields which are determined by elliptic curve domain parameters. The ECC domain parameters over Fq is defined as
D = (q, FR, a, b, G, n, h), where
• q: prime power, that is q = p or q = 2m, where p is a prime • FR: field representation of the method used for representing field elements • a, b: field elements, they specify the equation of the elliptic curve E over Fq,
Fq ax
b
• G: A base point represented by G= (xg, yg) on E(Fq ) • n: Order of point G , that is n is the smallest positive integer such that nG = O • h: cofactor, and is equal to the ratio #E(Fq)/n, where #E(Fq) is the curve[4]. B. Key Generation Alice’s (or Bob’s) public and private keys are associated with a particular set of elliptic key domain parameters (q, FR, a, b, G, n, h). Alice generates the public and private keys as follows 1. Select a random number d, d
[1, n – 1]
2. Compare Q = dG. 3. Alice’s public key is Q and private key is d. It should be noted that the public key generated needs to be validated to ensure that it satisfies the arithmetic requirement of elliptic curve public key.[4]
a. ElGamal Elliptic Curve Encryption Elliptic curve cryptography can be used to encrypt an image, M, into cipher text. The image M is encoded into a point PM form the finite set of points in the elliptic group, Eq(a,b). The first step consists in choosing a generator point G
Eq(a,b),such that the smallest value of n such that n G=O is
a very large prime number. The elliptic group Eq(a,b) and the generator point G are made public. Each user select a private key, nA <n and compute the public key PA = nA GA . To encrypt the point PM for Bob, Alice chooses a random integer k and computes the cipher text pair of points PC using Bob’s public key PB : PC =[(kG),( PM+kPB )] [5].
III.
Results and Conclusions
In this paper, we have presented an application of ECC with Generator G in image encryption. ECC points convert into cipher image pixels at sender side and decryption algorithm is used to get original image within a very short time with a high level of security at the receiver side. Elliptic curves are believed to provide good security with smaller key sizes, something that is very useful in many applications. Smaller key sizes may result in faster execution timings for the image encryption, which are beneficial to systems where real time performance is a critical factor ECC can be used into a www.giapjournals.com
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security system such as video compression, face recognition, voice recognition, thumb impression, sensor network, industry and institutions.
References 1. William Stallings, Cryptography and Network Security, Prentice Hall, 4th Edition, 2006. 2. V. Miller, “Uses of elliptic curves in cryptography”, Advances in Cryptology, Springer-Verlog New York,1986 3. Jeffrey L. Vagle, “A Gentle Introduction to Elliptic Curve Cryptography”,BBN Technology,Nov21,2010. 4. D.Hankerson, A.Menezes, and S.A. Vanstone, Guide to Elliptic Curve Cryptography, SpringerVerlag, 2004. 5. ElGamal, T., “A public key cryptosystem and a Signature scheme based on discrete logarithm,” IEEE Trans. Informn, Theory, IT-31, no.4, pp 469-472, July 1985.
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CIRCULAR MICROSTRIP TEXTILE ANTENNA Prof. Kiran Rathod1, PranjalGupta2, Bhavik Janjmera3, Suchit Patel4, Jignesh Bhagat5 Dept. of Electronics and Tele-Communication Engineering, Mumbai University, Mumbai-400 098, India 1
kiranrathod@gmail.com, 2iverson45@gmail.com, 3bhavikjanjmera@gmail.com
Abstract The speed of technology and its evolution with the help of human efforts and his thinking is growing like wildfire. Also the man machine relation has further taken forward big technical leaps in the world of Antenna and Microwave Technology. In near future we will see clothing and textile material to be lined up for antenna technology and together will be known as “Smart Clothes”. In this paper, circular microstrip for wearable application is been designed. This wearable is used to meet Bluetooth specifications and has been developed by using copper conducting parts and electrotextile (smart clothes). In this case jeans or cotton materials are used. Keywords—circular patch antenna, wearable antenna, radiation pattern, fabric characterization,gain. I.
Introduction
Advances in communication and electronic technologies have enabled the development of compact and intelligent devices that can be placed on human body or implanted inside it.The new generation of textile has the capability to conduct electricity and at the same time is wearable. There are much more applications involved if an antenna is made that are totally wearable. We use this new property of conductivity in textile material to implement the wireless functions to clothing. In general, the antennas are made of metal which are highly conductive and also is solid structured which is fixed and hence give the stable output. The challenge with textile antenna is that, because the antenna is purely textile with the radiating element as well as dielectric material and ground being textile, which can be folded and twisted, output stability is the major factor that should be taken into consideration.There are some applications at present, where the antennas are used to continuously monitor the biometric data of human body. In order to do this, they need to be so close to the human body all the time so that they can continuously monitor the biometric data and send the information to the outside world. If the antenna is hard it is not suitable to always keep them attached with the human body as they can make some harm due to their physical structure.
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Fig.1. Wearable Antenna If the antenna is made of textile material they will not make any harm to human body and will be totally wearable. This is the main motivation This has led humans to introduce special networks called Body Area Networks (BANs). This BANs will be a great boost in future for many purposes and interested area being healthcare and emergency services like military applications etc. This antenna is designed to work at 2.45GHz.A comparison between different textile material and their effect on gain, radiation efficiency has also been presented The simulation software Zeland IE3D is used to simulate the antennas. This software uses Method of Moment technique. It solves the entire electromagnetic phenomenon related with the antenna by using integral method. This approach gives a very accurate simulated result. II.
Antenna Design Procedure
The reason of using circular microstrip antenna is that it occupies less physical area as compared to rectangular antenna, in application of arrays circular geometry is preferred. The basic structure is shown in figure 2, comprising of thin conducting circular microstrip on a insulating dielectric substrate backed by ground plane. Also it necessary to know the exact value of dielectric constant of substrate (textile material) chosen.
Fig.2. Circular Patch Antenna
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Table 1 •
Resonance Frequency (fr) = 2.45GHz.
•
Height of Substrate (h) = 2.84 mm.
•
Relative permittivity (εr) = 1.67.
•
Loss Tangent (tan δ) = 0.02.
The resonant frequency for the dominant mode of propagation, in case of circular patch antenna is written as: . µ
………………….(1)
The formula for effective radius is, 1
ln
1.7726
/
……........(2)
The effective length can also be calculated by equating the area of circulat microstrip antenna with area of rectangular antenna. The length L of the RMSA is taken as diameter 2a of the CMSA, which is important fromthe field variation point of view. The widthWof the RMSA is then calculatedby equating its area with that of the CMSA, which comes out to be W =πa/2. From the effective dimensions of rectangular microstrip antenna, ae can be obtained as
………………. (3)
An infinite ground plane is assumed to avoid (i) back lobes in radiation pattern of the antenna, (ii) to reduce diffraction and scattering effects at the edges of the ground plane and to (iii) minimize the undesirableeffects of surface waves.
III.
Simulation Results
The simulation is carried out between 2 GHz to 3GHz frequency. A. Farfield Radiation Pattern. The farfield radiation pattern of circular microstrip antenna is
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Fig. 3. Radiation pattern B. Gain and efficiency
Fig. 4. Gain vs frequency using two different materials. C. Directivity vs Frequency. The directive gain obtained is 8.26 dB and power gain is 5.75 dB at design frequency of 2.45 GHz.
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Fig. 5. Directivity vs frequency. D. Efficiency vs frequency. The efficiency for case 1 is 56.12% and for case 2 is around 50%.
Fig. 6. Efficiency vs frequency. E. Comparison with other antennas. For an identical design, Circular microstrip antenna gives similar performance characteristics as that of rectangular microstrip antenna. The main advantage being that it occupies less physical area as compared to rectangular microstrip antenna.Various physical parameters for design in Appendix 1.
IV.
Conclusion
From the results obtained of this antenna we conclude that a circular microstrip antenna is better option for wearable applications as it also occupies less physical area. The performance parameters of this
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textile antenna is comparable to copper based microstrip antennas and they are easy to build and drapable.We also conclude that textile microstrip antenna are very good alternatives to standard PCB substrate antenna for different applications. WEARABLE ANTENNAS ARE THE FUTURE.
References 1. http://gruoper.ieee.org/groups/802/15/ 2. Constantine A. Balanis, “Antenna Theory: Analysis and design” Constantine A.Balanis, “ADesign”, 2nd edition, JohnSingapore, pp 722-736, 19. 3. Girish Kumar, K. P. Ray, “Broadband Microstrip Antennas”. 4. www.microwave101.com 5. www.antenna–theory.com Appendix 1 Physical design parameters Design Parameters
Antenna # 1
Antenna # 2
Antenna # 3
Antenna # 4
Resonant Frequency
2.45 GHz
2.45 GHz
2.45 GHz
2.45 GHz
Substrate Dielectric Constant
1.51
1.47
1.44
1.48
Substrate Thiclness(mm)
3.0
3.0
2.85
3.0
Loss Tangent Of Substrate
0.02
0.02
0.01
0.02
Copper
Copper
Copper
Copper
Wash Cotton
Curtain Cotton
Polyester
polycot
Materials Used For Ground Plane and Patch Insulating Fabric Material Employed
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SIMULATION AND IMPLEMENTATION OF ELLIPTICAL MICRO STRIP ANTENNA AT 750MHZ Kiran Rathod, Tushar Tanna, Raj Davda, Paresh Prajapati, K J Somaiyya College of Engineering, Mumbai, India kiranrathod@gmail.com,tanna48@gmail.com,raj4kjsieit@gmail.com, pparesh12@gmail.com
Abstract In telecommunication industry, several types of antennas are used. The most common of which are the micro strip patch antennas (also known as printed antennas) or patch antenna. Patch antennas can be used in many types of communications links that may have varied requirements. A single patch antenna provides a maximum directive gain of around 6-9 dBi. We can design it to work at multiple frequencies. It is available in various shapes and configuration, most common of which is a rectangular micro strip antenna (RMSA).In this project we are designing single fed annular ring micro stripantenna. The software used to model and simulate the micro strip patch antenna is ZeelandIncâ&#x20AC;&#x2122;s IE3D software. IE3D is a full-wave electromagnetic simulator based on the method of moments. It analyzes 3D and multilayer structures of general shapes. It has been widely used in the design of MICs, RFICs, patch antennas, wire antennas, and other RF/wireless antennas. An evaluation version of the software will be used to obtain the results. I.
Introduction
Microstrip antennas (MSAs) have several advantages, including that they are lightweight and smallvolume and that they can be made conformal to the host surface. In addition, MSAs are manufactured using printed-circuit technology, so that mass production can be achieved at a low cost.In high performance aircrafts, spacecrafts, satellites, missiles and other aerospace applications where size, weight, performance, ease of installation and aerodynamics profile are the constraints, a low or flat/conformal profile antenna may be required. In recent years various types of flat profile printed antennas have been developed such as Microstrip antenna (MSA). MSAs, which are used for defense and commercial applications, are replacing many conventional antennas. However, the types of applications of MSAs are restricted by the antennasâ&#x20AC;&#x2122; inherently narrow bandwidth (BW). Accordingly, increasing the BW of the MSA has been a primary goal of research in the field. This is reflected in the large number of papers on the subject published in journals and conference proceedings. In fact, several broadband MSA configurations have been reported in the last few decades.
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II.
Overview
The concept of microstrip radiators was first proposed by Deschamps as early as 1953. The first practical antennas were developed in the early 1970’s by Howell and Munson. Since then, extensive research and development of microstrip antennas and arrays, exploiting the new advantages such as light weight, low volume, low cost, low cost, compatible with integrated circuits, etc., have led to the diversified applications and to the establishment of the topic as a separate entity within the broad field of microwave antennas. III.
Working of Microstrip Antenna
The patch acts approximately as a calls on the sides). In a cavity, only certain modes are allowed to exist, at different resonant frequencies. If the antenna is excited at a resonant frequency, a strong field is set up inside the cavity, and a strong current on the bottom surface of the patch. This produces significant radiation (a good antenna). IV.
Feeding Technique
The Coaxial feed or probe feed is a very common technique used for feeding Microstrip patch antennas. As seen from Figure 3.5, the inner conductor of the coaxial connector extends through the dielectric and is soldered to the radiating patch, while the outer conductor is connected to the ground plane. The main advantage of this type of feeding scheme is that the feed can be placed at any desired location inside the patch in order to match with its input impedance. This feed method is easy to fabricate and has low spurious radiation. However, its major disadvantage is that it provides narrow bandwidth and is difficult to model since a hole has to be drilled in the substrate and the connector protrudes outside the ground plane, thus not making it completely planar for thick substrates (h > 0.02λo). Also, for thicker substrates, the increased probe length makes the input impedance more inductive, leading to matching problems. It is seen above that for a thick dielectric substrate, which provides broad bandwidth, the microstrip line feed and the coaxial feed suffer from numerous disadvantages. The non-contacting feed techniques discussed below, solve these problems.
Fig.1 : Block Diagram
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a. Design Procedure The transmission line model described in chapter will be used to design the antenna. Step 1: Calculation of Major axis (a): The width of the Micro strip patch antenna is given by equation (3.6) as:
Substituting c = 3e8 m/s, εr = 4.3and fo = 750 Mhz, we get: W = 0.122 m = 122.00 mm Step 2: Calculation of Effective dielectric constant (ε reff): Equation (3.1) gives the effective dielectric constant as:
Substituting εr = 4.3 , W = 122.0 mm and h = 1.6 mm we get: εreff = 4.16 Step 3: Calculation of the Effective length (Leff ): Equation (3.4) gives the effective length as:
Substituting, c = 3e8 m/s and f o = 750 MHz we get: L eff = 0.11554 m = 115.54 mm Step 4: Calculation of the length extension ( ΔL ): Equation (3.2) gives the length extension as:
Substituting εref f = 4.16, W = 122.0 mm and h = 1.6 mm we get: ΔL = 0.771528 mm
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Step 5: Calculation of actual length of patch ( L ): The actual length is obtained by re-writing equation (3.3) as: L= Leff −2Δ L Substituting L eff = 115.54 mm and ΔL = 0.771528 mm we get: L = 0.114 m = 114.00 mm = 2a Step 6: Calculation of Minor axis (b): The width of the Micro strip patch antenna is given by equation (3.6) as:
Substituting c = 3e8 m/s, εr = 4.3and fo = 900 Mhz, we get: W = 0.102 m = 102.00 mm Step 7: Calculation of Effective dielectric constant (ε reff): Equation (3.1) gives the effective dielectric constant as:
Substituting εr = 4.3 , W = 122.0 mm and h = 1.6 mm we get: εreff = 4.15 Step 8: Calculation of the Effective length (Leff ): Equation (3.4) gives the effective length as:
Substituting, c = 3e8 m/s and f o = 750 MHz we get: L eff = 0.09543 m = 95.43 mm Step 9: Calculation of the length extension ( ΔL ): Equation (3.2) gives the length extension as:
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Substituting εref f = 4.15, W = 102.0 mm and h = 1.6 mm we get: ΔL = 0.7716 mm Step 10: Calculation of actual length of patch ( L ): The actual length is obtained by re-writing equation (3.3) as: L= Leff −2Δ L Substituting L eff = 95.43 mm and ΔL = 0.7716 mm we get: L = 0.093 m = 93.00 mm = 2b Step 11: Calculation of the ground plane dimensions (L g and W g) : The transmission line model is applicable to infinite ground planes only. However, for practical considerations, it is essential to have a finite ground plane. It has been shown by that similar results for finite and infinite ground plane can be obtained if the size of the ground plane is greater than the patch dimensions by approximately six times the substrate thickness all around the periphery. Hence, for this design, the ground plane dimensions would be given as: Lg = 6 h + 2a = 6(1.6) + 114.00mm = 123.6 mm Wg = 6 h + 2b = 6(1.6) + 93 = 102.6 mm Step 12: Determination of feed point location (X f, Y f ) : A coaxial probe type feed is to be used in this design. As shown in Figure 4.1, the center of the patch is taken as the origin and the feed point location is given by the co-ordinates (X f, Y f ) from the origin. The feed point must be located at that point on the patch, where the input impedance is 50 ohms for the resonant frequency. Hence, a trial and error method is used to locate the feed point. For different locations of the feed point, the return loss (R.L) is compared and that feed point is selected where the R.L is most negative. According to there exists a point along the length of the patch where the R.L is minimum. Hence (xf ,yf)=(30mm, 28mm) b. Radiation Pattern plots Since a microstrip patch antenna radiates normal to its patch surface, the elevation pattern for φ = 0 and φ = 90 degrees would be important. Figure 4.2 shows the gain of the antenna at 4 GHz for φ = 0 and φ = 90 degrees.
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Figure 4.2 Elevation Pattern for Φ = 0 and Φ = 90 degrees The maximum gain is obtained in the broadside direction and this is measured to be 6.02 dBi for both, Φ = 0 and Φ = 90 degrees.
Figure 4.3. Radiation pattern in E-plane and H-plane The back lobe radiation is sufficiently small and is present due to finite ground plane. The average current distribution in the feed patch is shown in figure 4.4. Figure 4.4. Current distribution in Microstrip antenna
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c. 3-D Radiation Pattern
Figure 4.5. 3-D Radiation Pattern Microstrip antenna V.
Information:
Comparison of different feeding technique
VI.
Applications
1. Used in telecommunication industry 2. Used in aircrafts and missiles 3. Designed for multiple frequency www.giapjournals.com
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4. Due to its excellent frequency response can be used in various field VII.
Scope in Future
The micro strip antenna finds various applications in various important fields. The fact that micro strip antenna is used for planar and non-planar surfaces it can be used extensively in almost all kinds of applications. The major field where the micro strip antenna can be used is aircraft satellites and in missions of celestial bodies. The micro strip also has ability to be fabricated on a PCB which makes it distinctly unique and thus allowing the it to be used in micro-applications as well. The micro strip can be used in high frequency application which also is an added advantage. All these reasons just assert the fact micro strip antenna is “The” antenna for future applications in this technologically advancing world.
VIII.
Conclusion:
The results obtained in this study reveal that the elliptical microstrip antenna is suitable for wireless communication. In this paper microstrip antenna for wireless communication have been designed using FR4 substrate. References: 1. C. A. Balanis, “Antenna Theory, Analysis and Design,” John Wiley & Sons, New York, 1997. 2. Ray K.P. and Kumar Girish,” Broadband Microstrip Antenna,” Artech House, UK, 2003 3. Antennas-John D. Kraus, Tata McGraw Hill publication 4. D. M. Pozar and D. H. Schaubert, Microstrip Antennas: The Analysis and Design of Microstrip Antennas and Arrays, IEEE Press, 1995. 5. http://en.wikipedia.org/wiki/microstrip_antenna(28/10/2011) 6. http://www.dspguide.com/ch27/6.htm(1/11/2011)
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CHEMICAL BATTERY AS SUBSTITUTE TO CONVENTIONAL FUEL Sahil Inamdar, Akshay Tharval, Bhoomika Sheth, Chemical Department, D. J. Sanghvi College of Engineering, Mumbai 400056 sahil.inamdar@gmail.com, tharval.akku@gmail.com, bhoomika4793@gmail.com
Abstract In this paper we have discussed the possible means to run a car using chemical engineering and various chemical reactions. The main purpose of this paper is to solve the world fuel crisis with a simple household solution. We have highlighted the use of chemical cells for the same by making use of a working model of a small car. Our experiments demonstrate the use of lemon batteries as a substitute to the traditional alkaline batteries. Lemon juice containing citric acid makes up an excellent electrolyte using Copper and Magnesium as electrodes. The working of a cell is based on simple electrolytic cell which is a combination of redox reactions. The power drawn by the cell is directly proportional to the concentration of lemon juice used. A single lemon cell gives enough voltage to power an LED. During this experiment we found out that the current drawn per cell is very less. Connecting enough cells in series and parallel combinations draws enough power to run a motor of the car. Because of the small current being drawn the final battery was very bulky. To overcome this difficulty we found out various other solutions which can draw more power than lemon juice. They are •
Bleach cell
•
Salt cell
•
Vinegar cell
Among the above solutions, bleach cell is the most efficient and long lasting. All the above mentioned cells including the Lemon cell are eco friendly i.e. there isn’t any waste or toxic gases evolving. Using chemical cells and improvising them on a larger scale can certainly help reduce the energy crisis all over the world. Keywords: Alkaline batteries, concentration, electrolyte, series & parallel combinations.
I.
INTRODUCTION
Nothing happens in the world without energy. Civilizations would collapse if it ceased to be available. Civilizations advance by deploying energy in ever greater abundance. Petroleum is one of the legacies of the past, being the partially decomposed residue of organic matter, such as plankton and algae, that sank to the bottom of lakes and seas and was later subjected to heat and pressure. It is, of course, an extraordinarily convenient source of energy, as it can be transported easily, even in weight-sensitive aircraft.
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Chemical Engineers contribute at all levels and to all aspects of developing both new sources of energy and more efficient applications of current sources. Chemical Engineers have long contributed to the refinement of this raw material, which is squeezed and pumped from the ground. They have developed processes and catalysts that have taken the molecules provided by nature, cut them into more volatile fragments, and reshaped them so that they burn more efficiently. Of course, burning natureâ&#x20AC;&#x2122;s underground bounty might be seen, especially by future generations, as the wanton destruction of an invaluable resource. The supply of petroleum is also finite and, although new sources of petroleum are forever being discovered, for the time being at least, they are proving hazardous and increasingly expensive to access and use. Although an â&#x20AC;&#x153;emptyâ&#x20AC;? Earth is decades away, one day non-renewable resources such as petroleum will be depleted. Chemical Engineers are already at work on the development of new sources of energy. Nature, with its head start of four billion years on laboratory, Chemical Engineers have already developed a highly efficient system based on chlorophyll. Electrochemistry, the use of chemical reactions to generate electricity and the use of electricity to bring about chemical change, is potentially of huge importance to the world. Chemical Engineers have already helped to produce the mobile sources, the batteries that drive our small portable appliances, such as lamps, music players, laptops, telephones, and monitoring devices of all kinds, as well as, increasingly, our cars. Finally, there are various other methods to generate energy such as the solar energy and wind energy. But the generation of electricity from these sources requires huge plants to be set up which are very complicated and costly. Also highly skilled labour is required to run and handle such plants. Hence the use of simple household methods to generate electricity comes in handy. A novel technique which we practised was with the use of a lemon cell i.e. Lemon juice (citric acid) as electrolyte in our electrochemical cell. In our method copper and magnesium strips are used as the two electrodes. In this process redox reaction takes place, which is the main reason for power generation. In this reaction the anode metal oxidises and electrons flow through the electrolyte to the cathode thus completing the circuit. By connecting external wires we can work up several electrical devices. II.
BATTERY DESIGN
Cuvettes are used to hold the lemon juice (100% concentrated). 5 ml of the electrolytic solution was used. Magnesium and copper strips were dipped inside the juice, taking care that the two electrodes do not touch each other in the electrolyte. For this purpose clay can be used as it does not react in the solution and also provides a firm base for the electrodes where they can be mounted on. Connect wires to the free end of the electrodes.
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Fig1. Materials used
Fig2. Sample lemon Battery
III.
EXPERIMENT
A potential difference of about 1.7V was measured across the two terminals of the cell by making the above set up. The motors used in this experiment were standard 9V, 100 rpm motors. To increase the voltage many such single cells were connected in series combination. Sr. No.
No. of cells in series connection
Voltage measured (Volts)
1.
1
1.7
2.
2
3.4
3.
4
7.0
4.
6
10.3
5.
10
15.8
This voltage received was much more than the current obtained. It was observed that the current measured from a single cell was comparatively low i.e. 0.1 micro Amps. It was noted that the motors www.giapjournals.com
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were working on the principle of maximum power dissipated. Power being a product of potential difference and current (V*I) had to be maximised. To overcome this difficulty we connected single cells in parallel so that the current value rises up. Sr. No.
No. of cells in parallel Current measured connection
(micro Amps)
1.
2
0.15
2.
6
0.4
3.
10
0.79
4.
15
1.1
5.
20
1.4
By keeping cells in parallel the voltage was not affected. The goal was to maximize the performance of our car. Increasing the number of cells connected in series will increase the voltage supplied by the battery. Increasing the voltage supplied to a dc electric motor will increase its maximum rotational speed. Increasing the number of cells connected in parallel will increase the current supplied by the battery. Increasing the current supplied to a dc electric motor will increase the maximum applied torque of the motor. Thus by numerous trial and error methods it was found that 20 cells of such kind when connected in parallel provided enough power to run a motor. Though enough to run the motor, it was not enough to run a car. Hence two batches of twenty cells in parallel each were connected in series which helped to get the required current as well as voltage and in return the power to run the two adjacent motors of the car. This same procedure was repeated for the other two motors. IV.
HOW IS POWER GENERATED?
The energy for the battery comes from the chemical change in the Magnesium when it dissolves into the acid. The energy does not come from lemon (electrolyte). Magnesium is oxidized inside the lemon, exchanging some of its electrons with the acid in order to form hydrogen gas in the electrolytic solution which evolves from the copper (cathode). The Magnesium (anode) reaches a lower energy state, and the energy released provides the power. This power generated is enough to light up a LED for three days. V.
MECHANISM
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When the cell is providing an electrical current through an external circuit, the metallic Magnesium at the surface of the Magnesium electrode is dissolving into the solution. Magnesium atoms dissolve into the liquid electrolyte as electrically charged ions (Mg2+), leaving 2 negatively charged electrons (e-) behind in the metal: Mg → Mg2+ + 2eThis is an oxidation reaction. While Magnesium is entering the electrolyte, two positively charged hydrogen ions (H+) from the electrolyte combine with two electrons at the copper electrode's surface and form an uncharged hydrogen molecule (H2): 2H++ 2e- → H2 This is a reduction reaction. The electrons used from the copper to form the molecules of hydrogen are made up by an external wire or circuit that connects it to the Magnesium. The hydrogen molecules formed on the surface of the copper by the reduction reaction ultimately bubble away as hydrogen gas. VI.
PROBLEMS FACED
Fig 3. A single cell in reaction phase As seen in the above figure the hydrogen gas evolved was towering the cuvettes in its reaction phase. Hydrogen gas being combustible was seen as a hazard and had to be taken care of. Changing the ion concentration was one of the ideas. This could have been done by: •
Changing electrolyte concentration
•
Changing ion concentration
The electrolyte concentration was changed to 10%, 25%, 50% & 75% and then readings were taken for voltage. The following data was noted.
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Sr. no.
Concentration (%)
Voltage (V)
1.
10
0.2
2.
25
0.5
3.
50
0.8
4.
75
1.2
5.
100
1.7
Thus it was concluded to use 100% concentration of lemon juice. It was then decided to add salt to the electrolyte to check whether the ion concentration changes. It was observed that the addition of salt actually decreased the voltage from 1.7V to 1.53V making it unsuitable to use. VII.
CONCLUSION
It was seen that the batteries had enough power to run the motor but at a very slow speed. The motors when connected to the wheels werenâ&#x20AC;&#x2122;t able to withstand the weight of the car for too long and would abruptly stop. It was observed that after a certain span of time the potential difference between the two electrodes dropped. When the weight of the car was reduced, the car covered a greater distance than the previous case but stopped after sometime because of the weight again and also the magnesium electrode started to dissolve in the electrolyte and the copper strip changed colour. The major problem that occurred during the experiment was that these lemon cells were like â&#x20AC;&#x153;one time useâ&#x20AC;? or use and throw kind of batteries. They cannot be reused or recycled. The container had to be emptied and then refilled again after sometime as the efficiency of the battery decreased, this was because the lemon juice was not a very strong electrolyte and would dissociate fast. To overcome these difficulties we found an efficient option i.e. using bleach cell. Bleach cell The main aim for us to study about bleach cell was to get a very efficient substitute to lemon juice. Substituting the lemon juice in the cuvettes by pure bleach one can overcome the above mentioned difficulties. Make the use of the same electrodes i.e. copper and magnesium taking care that the two electrodes do not touch. An unloaded bleach cell records a potential difference of 1.87V across the two terminals while the current was 0.1 micro Amps. Suitable resistances ranging from 100 to 10k ohms can be used in the circuit. This will help to increase the current compromising the voltage which is of greater efficiency. One such cell connected to a 2.5k ohms resistor records a potential difference of 0.606V while the current shoots up to 0.25 mA. Connecting such cells in suitable series and parallel combinations helps increase the current and voltage and in return the power, helping the motor to run better. Though bleach cells took a little time to start up but once started it would give a www.giapjournals.com
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constant which lasted for a very long time. A single unloaded bleach cell can easily light up a LED for a weekâ&#x20AC;&#x2122;s time. VIII.
FUTURE PROSPECTS AND ADVANCEMENTS
The major advantage of a chemical battery is that there are no hazardous pollutants given out in the environment. Though the project carried out by us was on a small scale and to power a small car this idea can be implemented on a greater scale by improvising techniques used. Not only for cars or automobiles such technique can be used but also to power any small or large electronic gadget by improvising it. This can be done by increasing the number of cells used in series and parallel combination. This reduces the use of conventional sources of energy such as petroleum with simple material which can we can get in abundance cutting down the cost to a great extent.
Fig 4. Cuvettes holding the electrolyte
Fig 5. Arrangement of cells in the car
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Fig 6. Sample car
REFERENCES 1. Sorey, Timothy; Hunt, Vanessa; Balandova, Evguenia; Palmquist, Bruce (2012). "Juan's Dilemma: A New Twist on the Old Lemon Battery". In Metz, Steve. Fuel for Thought: Building Energy Awareness 2. General Chemistry Darrell D. Ebbing, Steven D. Gammon â&#x20AC;&#x201C; 2009 3. Lemon Battery Jesse Russell, Ronald Cohn - 2012
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DEVELOPMENT OF A DEVICE TO MEASURE THE BLADE TIP CLEARANCE OF AN AXIAL COMPRESSOR Dr. S.M.Khot*#1, Dr.A.M.Pradeep*&2, Sagar Chavan#3, Manasi Ghogare#4, Srushti Koli#5 *
Guides, #Mechanical Department, Fr.C.Rodrigues Insitute of Technology, Vashi, Navi Mumbai, India. &
Aerospace Department, Indian Institute of Technology, Bombay, India.
1
smkhot66@yahoo.co.in, 2ampradeep@aero.iitb.ac.in, 3csagar619@gmail.com, 4manasi2004@yahoo.in 5
srushti268@yahoo.com
Abstract Axial compressors, used in gas turbines, jet engines and also small scale power plants, are rotating, airfoil based compressors in which the working fluid flows parallel to the axis of rotation. There has been continuous struggle to maximize the efficiency of these compressors. One of the many ways to achieve the same is to minimize the tip clearance i.e. to reduce the distance between the blade tip and the housing. Experiments need to be conducted to measure the changes in the tip clearance while the compressor is operating. Conventional devices to measure this tip clearance have proven to be costly if a small scale application is under consideration. Our aim in this project is to develop a device which will measure the blade tip clearance of an axial flow compressor economically. The literature review, development of the device, its working and results will be discussed in this paper. Keywords- Tip Clearance Measurement, Eddy Current Probe, Data Storage Oscilloscope, Eddy Current Technique I.
INTRODUCTION
Minimizing the tip clearance reduces the amount of fuel burned, it lowers the rotor inlet temperature; thus improving turbine efficiency. The reduction of emissions results in extended service life of the compressor and also enhances the mission range capabilities in jet engines. The various methods available to measure this tip clearance include: A. Optical Fourier Domain Reflectrometry (OFDR) OFDR is a method used to measure back reflections from optical fiber networks and components. The signals reflected from the device under test interfere with the reflections from a fixed surface; OFDR detects these interfering signals and generates a Fourier transform of the same, thus allowing visualization of multiple reflections [1] of the same, thus allowing visualization of multiple reflections[1]. B. Laser Doppler Velocimetry (LDV) www.giapjournals.com
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In an LDV, two coherent laser beams are brought to an intersection under a small angle, such that inside the volume of intersection an interference fringe system with nearly parallel fringes of uniform spacing is generated [3]. An object passing perpendicularly through this measurement volume (i.e., here the turbine blade tip) scatters light that is amplitude modulated with the Doppler difference frequency. A wavelength sensitive detection of this frequency results in axial position of the moving object. C. Capacitive Sensor Method The capacitive sensor method works on the principle of capacitance. The main components of the capacitive proximity sensor are plate, oscillator, threshold detector and the output circuit. The plate inside the sensor acts as one plate of the capacitor and the target as another plate and the air as the dielectric between the plates [2]. As the object comes close to the plate of the capacitor, the capacitance increases and as the object moves away the capacitance decreases. The capacitive sensor can detect any targets whose dielectric constant is more than that of air. Though the above methods are widely used, they have their
respective disadvantages which are stated
below: â&#x20AC;˘
The optical methods i.e. OFDR and LDV are sensitive to contamination and are not suitable for compressors subjected to heavy vibrations.
â&#x20AC;˘
Capacitive sensors are affected by humidity and temperature variation; they are also difficult to design for practical applications.
â&#x20AC;˘
Optical devices are costlier than other devices available to serve this purpose and they are also very delicate and need extra care while in use.
II.
EDDY CURRENT TRANSDUCERS
The process of Electromagnetic Induction is responsible for the production of eddy currents. In this process an alternating current when applied to a conductor, such as copper wire, develops a magnetic field in and around the conductor. When this alternating current rises to maximum, the magnetic field expands and vice versa. Now, if a second conductor is brought in close proximity of this changing magnetic field, the current will be induced in the second conductor. Eddy currents are these induced currents which flow in a circular path. An eddy current transducer uses the principle of Electromagnetic Induction and generates eddy currents which can be used to detect the distance between the two conductors. The only constraint with this method is that the second conductor is to be metallic in order to generate eddies i.e. the blade of the turbine should be a metal, if in case a ceramic or plastic blade is used for a small scale application they can be given a metallic coating to make the blades suitable for this application. www.giapjournals.com
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A typical circuit which can be used to generate eddies and to measure the tip clearance is shown in Fig.1.
Fig.1 Eddy Current Transducer [5] In the above figure, the probe is used to generate the eddy currents. It consists of an active and a compensating coil. The magnetic flux is induced in the active coil and is passed through the conducting material (second conductor) to produce eddy currents. The compensating coil is given to provide temperature compensation; hence it is on the adjacent arm of the bridge circuit. The eddy current is detected with the help of an analog meter through which the output can be visually seen. A. Advantages: •
Sensitive to small distance variation.
•
Equipment is portable.
•
Minimum part preparation is required.
•
Economical method.
•
Can work in arduous environmental condition.
B. Disadvantages: •
Only conductive elements can be inspected, but non-conducting elements can be given a metallic coating.
•
Range of the eddy probe is limited to 4 to 5 mm, but the tip clearance ranges between 3 to 4mm.
III.
DEVELOPMENT OF THE TIP CLEARANCE MEASURING DEVICE
The components required to successfully implement the circuit and to conduct the testing are: www.giapjournals.com
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A. Eddy Current Probe: In order to generate the eddy current, eddy probes are used. There are many such probes available for a variety of applications but choosing the appropriate probe to suit the application is important. The types of probes available are: â&#x20AC;˘ Differential Probes: These probes have two active coils wound in opposition and are used to detect surface defects[8]. When both the active coils are over a smooth surface they do not show any differential signal, however if one of the active coils is over a defect then a differential signal is produced. Hence these probes are used for flaw detection. â&#x20AC;˘ Reflection Probes: These probes have two coils similar to differential probes but one coil is used to excite the eddy currents while other is used to sense the changes in the testing material
[8]
. These probes are the most
advantageous as both the coils can be optimized for the desired purpose. â&#x20AC;˘ Absolute Probes: These are simplest type of probes; they incorporate the basis of eddy current generation and have as active coil which produces the eddy current and a compensating coil[8]. Such probes are widely used because of their wide range of applications. Though the reflection probes are more accurate and can be optimized according to the application, they are costly. After comparing the reflection and absolute probes, it is found that the absolute probes are apt for this particular application.
Fig. 2 Eddy Current Pencil Probe Figure 2 shows the surface type pencil probe. The diameter of this probe is 5mm and its length is 4cm. Since the testing range of these probes is 4 to 5 mm they ensure accuracy in measurement. B. Resistance:
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The resistance shown in Fig. 3 is to be chosen depending upon the peak to peak voltage (which is 1 to 2 Volts) as specified by the manufacturer of the eddy probe. This resistance is finalized by trying out various set of standard resistance values and a value of 1k ohms is chosen.
Fig 3 Resistance(1000Ω) C. Function generator and Two channel Data Storage Oscilloscope: A function generator acts as an input device, wherein the values of frequency and input voltage can be set for the circuit. The value of limiting frequency is specified by the manufacturer of the probe and is 50 to 500 kHz. An input of 59 kHz is thus given to the circuit. A Two Channel Data Storage Oscilloscope (DSO), as shown in the Fig. 4, acts as an output device and also gives the waveforms related to the input as well as output values. Since the obtained readings from the DSO can be stored, accuracy is ensured.
Fig. 4 Two Channel Data Storage Oscilloscope. IV.
PRECAUTIONS
The following precautions are taken into consideration before testing the probe: •
Meeting the specified voltage/current constraints of each component used, failure of which may result in severe damage to those expensive components.
•
Working out the circuit on paper, making sure it is a closed circuit, before attempting it on the bread board.
V.
EXPERIMENTAL SETUP Initially the testing of the probe is done with a metal plate and the entire setup is as shown in Fig. 5.
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Fig. 5 Circuit Used to Test the Probe. Two wires of input from the function generator are taken, one of which goes to the bread board and the other goes to the DSO. Output from the breadboard goes to the DSO and hence we get the input-output waveforms. The metal plate is kept at varying distances from the probe tip and the corresponding change in the voltage is noted. The metal plate kept with respect to the probe is shown in Fig. 6.
Fig .6
Positioning of the Probe with Respect to the Conducting Plate.
Waveforms of each of the readings were obtained with the help of the DSO as shown in Fig.7:
Fig.7 Waveform generated at different distances www.giapjournals.com
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Since the output voltage is in millivolts, there is a need for an amplification circuit. For amplification, the value of resistance is decreased to 470 Ohms and in order to get precise readings the distance between the metal place and the probe tip is varied in steps of 0.2mm using a micrometer and the corresponding voltage values are tabulated below in Table 1. Table. I Variation of voltage readings with deflection of conductor plate from probe tip. Distance
Voltage (mV)
0
110
0.2
100
0.4
98
0.6
94
0.8
96
1
94
1.2
92
1.4
92
1.6
90
1.8
90
2
89
A graph was plotted with the help of the readings obtained, in order to get an overall idea about how the voltage varies with respect to the change in distance. The graph obtained is as shown in Fig. 8. Tip Clearance Measurement
Voltage(mV)
120
y = ‐8.045x + 103.0 R² = 0.778
80 40
Volts Linear (Volts)
0 0
1
2
3
Distance(mm)
Fig.8
Calibrating graph giving relation between the distance and voltage
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As observed, the voltage varies inversely with the distance between the metal conductor and the probe tip given by the Eq. 1 .
y = -8.045x + 103.0
(1)
Thus, for a given value of voltage (y), we can calculate the distance (x) using the above equation thus giving us the value of the tip clearance in this case. The above values obtained are checked for accuracy and hence the percentage error is calculated. The following table shows the calculated error. Table. II: Error calculation Actual Distance
Voltage (mV)
Distance
Error
obtained 0
110
0
0.2
100
0.37
46.73%
0.4
98
0.62
35.72%
0.6
94
1.11
46.73%
0.8
96
0.87
8%
1
94
1.11
9.91%
1.2
92
1.36
12.30%
1.4
92
1.36
-2.90%
1.6
90
1.616
0.90%
1.8
90
1.616
-11.38%
2
89
1.74
-14.93%
According to the values obtained it is seen that the average error is 13.11%, since the value is below 20% it can be said that the error is within acceptable limits. VI.
RESULTS
â&#x20AC;˘
The Eddy probe is tested successfully and the readings as obtained are tabulated as shown in Table 1.
â&#x20AC;˘
The readings show that if the distance between the probe and the conducting plate is varied then the voltage changes along with it with an inverse proportion.
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VII.
CONCLUSION
The entire experiment proves that the Eddy current Transducer method is apt to measure the tip clearance change and the entire setup can be mounted on a test rig to measure the same. ACKNOWLEDGEMENT We are sincerely thankful to our H.O.D, 'Dr. S. M. Khot' and our principal 'Dr. Rollin Fernandes' for giving us an opportunity to work on this project. Also we would like to thank our external project guide Associate Professor 'A. M. Pradeep' of the Aerospace Department, IIT Bombay and our internal project guide 'Dr. S. M. Khot' for their valuable guidance and assistance throughout the course of this project. We are also thankful to Mr. Arvind from the electrical department of Fr.C.R.I.T for his immense co-operation and Prof. S. S. Thale for his guidance. REFERENCES
[1]. Andrei B. Vakhtin1, Shin-Juh Chen2, and Steve M. Massick3 , ”Optical Probe for Monitoring Blade Tip Clearance.” In conference at 47th AIAA Aerospace Sciences Meeting Including The New Horizons Forum and Aerospace Exposition 5 - 8 January 2009, Orlando, Florida.
[2]. A.G.Sheard , “Blade by Blade Tip Clearance Measurement.”, Hindawi Publishing Corporation International Journal of Rotating Machinery Volume 2011, Article ID 516128, 13 pages doi:10.1155/2011/516128
[3]. Lars Büttner, Thorsten Pfister, and Jürgen Czarske. , “Fiber-optic laser Doppler turbine tip clearance probe.” in international journal of OPTICS LETTERS,May 1, 2006 ,Vol. 31, No. 9.
[4]. S Z Cao, F J Duan and Y G Zhang “Measurement of Rotating Blade Tip Clearance with Fibre-Optic Probe.” Journal of Physics: Conference Series 48 (2006) 873–877
[5]. Web Link: http://www.InstruementationToday.com. [6]. Web Link: http://www.wikipedia.com. [7]. Web Link:http://www.chenyang-ism.com. [8]. Web Link: http://www.ndt-ed.org.
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GRAPHENE: THE ADVANCED MATERIAL Asim Kulkarni Indira College of Engineering and Management, Pune, India asimpkulkarni@gmail.com
Abstract Graphene is a rapidly rising star on the horizon of materials science and nanotechnology. This strictly two-dimensional material exhibits exceptionally high crystal and electronic quality, and, despite its short history, has already revealed a new dimension of physics and potential applications, which are briefly discussed here. Whereas one can be certain of the realness of applications only when commercial products appear, graphene no longer requires any further proof of its importance in terms of fundamental physics. More generally, graphene represents a conceptually new class of materials that are only one atom thick, and, on this basis, offers new inroads into low-dimensional physics that has never ceased to surprise and continues to provide a fertile ground for applications. Keywords - External quantum efficiency, Buckyballs, Van Der Waals forces. I. INTRODUCTION Graphene is a single atomic layer of carbon atoms tightly packed in a two-dimensional honeycomb lattice microscopy. The first graphene was extracted from graphite using a technique called micromechanical cleavage. This approach allowed easy production of high-quality graphene crystallites and further led to enormous experimental activities. . Graphene has a high electron (or hole) mobility as well as low Johnson noise (electronic noise generated by the thermal agitation of the charge carriers inside an electrical conductor at equilibrium, which happens regardless of any applied voltage) Combination of excellent electrical property and low noise make graphene an ideal material in the electronics. 2D materials display very interesting properties, and are fundamentally different from the 3D materials we encounter everyday. The discovery of 2D materials means that scientists now have access to materials of all dimensionalities, including 0D (quantum dots, atoms) and 1D (nanowires, carbon nanotubes) II. STRUCTURE Graphene is a member of the class of 2-dimensional materials. It consists of a hexagonal array of sp2bonded carbon atoms, just like those found in bulk graphite.
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. s
px+py
sp2
pz
Fig. 1: Atomic structure of Graphene in the form of quantum numbers. III. SYNTHESIS A. Exfoliation and Cleavage Graphite is stacked layers of many graphene sheets, bonded together by weak Van Der Waals force. Thus, in principle, it is possible to produce graphene from a high purity graphite sheet, if these bonds can be broken. Exfoliation and cleavage use mechanical or chemical energy to break these week bonds and separate out individual graphene sheets.
Fig. 2: Separation of Graphene sheets B. Thermal Chemical Vapor Deposition Techniques In this work, a natural, eco-friendly, low cost precursor, camphor, was used to synthesize graphene on Ni foils. Camphor was first evaporated at 180째C and then pyrolyzed, in another chamber of the CVD furnace, at 700 to 850째C, using argon as the carrier gas. Upon natural cooling to room temperature, fewlayer graphene sheets were observed on the Ni foils.
Fig. 3: Vapors containing Graphene being deposited. www.giapjournals.com
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C. Plasma Enhanced Chemical Vapor Deposition Techniques Interest in synthesizing graphene through plasma enhanced chemical vapor deposition (PECVD) is contemporary to that of exfoliation. The earliest report had proposed a DC discharge PECVD method to produce so called nanostructured graphite-like carbon (NG). Simplicity of the process immediately attracted attention of the scientific community and the same kind of process was followed by many research groups, worldwide.
Fig. 4: Graphene deposited on Plasma. PECVD method has shown the versatility of synthesizing graphene on any substrate, thus expanding its field of applications. Future developments of this method should bring out better control over the thickness of the graphene layers and large scale production. IV. PROPERITES Graphene has several good properties. It conducts heat readily, so it can be easily cooled. It can withstand temperatures of several thousand degrees. Graphene doesn't melt easily. It is, however quite flammable. If there is any oxygen, it will burn up. In addition to its exceptional electrical conductivity, graphene is the strongest known substance. By creating holes within a sheet of graphene, then â&#x20AC;&#x153;dopingâ&#x20AC;? those holes with desired impurities, semiconductors can be made that are nearly unbreakable and highly flexible. As a bonus, graphene is a superb heat conducting material, so heat would not be the problem it is with current semiconductor materials. Yet, optimism must remain guarded until tangible results have been produced. This novel material is atomically thin, chemically inert, consists of light atoms, and possesses a highly ordered structure. Graphene is electrically and thermally conductive, and is the strongest material ever measured. These remarkable properties make graphene the ideal material. One photon can be converted into multiple electrons. A paradigm shift in the materials industry is likely within the near-future as a variety of unique materials replaces those that we commonly use today, such as plastics. Among these new materials, graphene stands out. The single-atom-thick sheet of pure carbon has an enormous number of potential applications
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across a variety of fields. Its potential use in high-efficiency, flexible, and transparent solar cells is among the potential applications. A new discovery by researchers has revealed that graphene is even more efficient at converting light into electricity than previously known. Graphene is capable of converting a single photon of light into multiple electrons able to drive electric current. The discovery is an important one for next-generation solar cells, as well as other light-detecting and light-harvesting technologies. In most materials, one absorbed photon generates one electron, but in the case of graphene, it is seen that one absorbed photon is able to produce many excited electrons, and therefore generate larger electrical signals. It was known that graphene is able to absorb a very large spectrum of light colors. However now it is known that once the material has absorbed light, the energy conversion efficiency is very high. Our next challenge will be to find ways of extracting the electrical current and enhance the absorption of graphene. Then we will be able to design graphene devices that detect light more efficiently and could potentially even lead to more efficient solar cells
. Fig. 5: Graphene as substrate in Solar cell. V. APPLICATIONS AND USES A. Electrodes with very high surface area. Researchers have developed electrodes made from carbon nanotubes grown on graphene. The researchers first grow graphene on a metal substrate then grow carbon nanotubes on the graphene sheet. Because the base of each nanotube is bonded, atom to atom, to the graphene sheet the nanotube-graphene structure is essentially one molecule with a huge surface area. B. Lower cost solar cells: Researchers have built a solar cell that uses graphene as a electrode while using buckyballs and carbon nanotubes to absorb light and generate electrons; making a solar cell composed only of carbon. The www.giapjournals.com
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intention is to eliminate the need for higher cost materials, and complicated manufacturing techniques needed for conventional solar cells C. Transistors that operate at higher frequency. The ability to build high frequency transistors with graphene is possible because of the higher speed at which electrons in graphene move compared to electrons in silicon. Researchers are also developing lithography techniques that can be used to fabricate integrated circuits based on graphene. D. Lower cost of display screens in mobile devices. Researchers have found that graphene can replace indium-based electrodes in organic light emitting diodes (OLED). These diodes are used in electronic device display screens which require low power consumption. The use of graphene instead of indium not only reduces the cost but eliminates the use of metals in the OLED, which may make devices easier to recycle. E. Storing hydrogen for fuel cell powered cars. Researchers have prepared graphene layers to increase the binding energy of hydrogen to the graphene surface in a fuel tank, resulting in a higher amount of hydrogen storage and therefore a lighter weight fuel tank. This could help in the development of practical hydrogen fueled cars. F. Sensors to diagnose diseases. These sensors are based upon graphene's large surface area and the fact that molecules that are sensitive to particular diseases can attach to the carbon atoms in graphene. For example, researchers have found that graphene, strands of DNA, and fluorescent molecules can be combined to diagnose diseases. A sensor is formed by attaching fluorescent molecules to single strand DNA and then attaching the DNA to graphene. When an identical single strand DNA combines with the strand on the graphene a double strand DNA if formed that floats off from the graphene, increasing the fluorescence level. This method results in a sensor that can detect the same DNA for a particular disease in a sample. VI. DRAWBACKS Graphene’s "external quantum efficiency" is low – it absorbs less than 3% of the light falling on it. Furthermore, useful electrical current can only be extracted from graphene-based devices that have electrical contacts with an optimized "asymmetry" – something that has proven difficult to achieve. Graphene-related materials existed only as conductors or insulators, never as semi-conductors. Graphene has a low energy band gap, so graphene continues to conduct a lot of electrons even in it’s off state. If there were billions of graphene transistors on a chip, a large amount of energy would be wasted
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VII. CONCLUSION Although graphene has shown exceptional electrical, optoelectric, and chemical properties and thus, has excellent potential be used as transparent electrode, field effect transistor, sensors and energy applications, synthesis of graphene films on arbitrary substrates, with desired energy band gap, still remained to be achieved. It is expected that after complete development of graphene films, on a large scale, with desired electrical properties, graphene may become more attractive and thus provide future electric devices. REFERENCES [1] Mechanical and Electrical Properties of Graphene Sheets by Joseph Scott Bunch. [2] National Science Foundation: Graphene (Images). [3] BBC News Article: Is graphene a miracle material? [4] Synthesis of Graphene and Its Applications: A Review by Indranil Lahiri, Raghunandan Seelaboyina, and Yong Soo Kang. [5] http://engineering.ucsb.edu. [6] http://www.futurity.org/.
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NON CONVENTIONAL ENERGY SOURCES: SOLAR POND Tejas Gawade, Varun Shinde, Ketan Gawade Department of MechanicalEngineering K.G.C.E , Karjat, Navi Mumbai, India tejas61191@gmail.com, shindevarun60@yahoo.com, ketangwd@gmail.com
Abstract The sun is the largest source of renewable energy and this energy is abundantly available in all parts of the earth. It is in fact one of the best alternatives to the non-renewable sources of energy. One way to tap solar energy is through the use of solar ponds. Solar ponds are large-scale energy collectors with integral heat storage for supplying thermal energy. It can be use for various applications, such as process heating, water desalination, refrigeration, drying and power generation. The solar pond works on a very simple principle. It is well-known that water or air is heated they become lighter and rise upward e.g. a hot air balloon. Similarly, in an ordinary pond, the sun’s rays heat the water and the heated water from within the pond rises and reaches the top but loses the heat into the atmosphere. The net result is that the pond water remains at the atmospheric temperature. The solar pond restricts this tendency by dissolving salt in the bottom layer of the pond making it too heavy to rise. Though solar ponds can be constructed anywhere, it is economical to construct them at places where there is low cost salt and bittern, good supply of sea water or water for filling and flushing, high solar radiation, and availability of land at low cost. Keywords- Solar thermal energy, Convecting Solar Ponds, Nonconvecting Solar Ponds, Salinity gradient, Desalination I.
INTRODUCTION
A solar pond is simply a pool of saltwater which collects and stores solar thermal energy. The saltwater naturally forms a vertical salinity gradient also known as a "halocline", in which low-salinity water floats on top of high-salinity water. The layers of salt solutions increase in concentration (and therefore density) with depth. Below a certain depth, the solution has a uniformly high salt concentration. There are 3 distinct layers of water in the pond: •
The top layer, which has a low salt content.
•
An intermediate insulating layer with a salt gradient, which establishes a density gradient that prevents heat exchange by natural convection.
•
The bottom layer, which has a high salt content.
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If the water is relatively translucent, and the pond's bottom has high optical absorption, then nearly all of the incident solar radiation (sunlight) will go into heating the bottom layer. When solar energy is absorbed in the water, its temperature increases causing thermal expansion and reduced density. If the water were fresh, the low-density warm water would float to the surface, causing convection current. The temperature gradient alone causes a density gradient that decreases with depth. However the salinity gradient forms a density gradient that increases with depth, and this counteracts the temperature gradient, thus preventing heat in the lower layers from moving upwards by convection and leaving the pond. This means that the temperature at the bottom of the pond will rise to over 90°C while the temperature at the top of the pond is usually around 30 °C. A natural example of these effects in a saline water body is Solar Lake in the Sinai Peninsula of Egypt. The heat trapped in the salty bottom layer can be used for many different purposes, such as the heating of buildings or industrial hot water or to drive an organic Rankine cycle turbine or Stirling engine for generating electricity. II. TYPES OF SOLAR PONDS There are two main categories of solar ponds: •
nonconvecting ponds, which reduce heat loss by preventing convection from occurring within the pond; and
•
convecting ponds, which reduce heat loss by hindering evaporation with a cover over the surface of the pond.
A. Convectıng Solar Ponds: A well-researched example of a convecting pond is the shallow solar pond. This pond consists of pure water enclosed in a large bag that allows convection but hinders evaporation. The bag has a blackened bottom, has foam insulation below, and two types of glazing (sheets of plastic or glass) on top. The sun heats the water in the bag during the day. At night the hot water is pumped into a large heat storage tank to minimize heat loss. Excessive heat loss when pumping the hot water to the storage tank has limited the development of shallow solar ponds. Another type of convecting pond is the deep, saltless pond. This convecting pond differs from shallow solar ponds only in that the water need not be pumped in and out of storage. Double-glazing covers deep saltless ponds. At night, or when solar energy is not available, placing insulation on top of the glazing reduces heat loss. B. Nonconvectıng Solar Ponds: There are two main types of nonconvecting ponds: salt gradient ponds and membrane ponds. A salt gradient pond has three distinct layers of brine (a mixture of salt and water) of varying concentrations.
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Because the density of the brine increases with salt concentration, the most concentrated layer forms at the bottom. The least concentrated layer is at the surface. The salts commonly used are sodium chloride and magnesium chloride. A dark-colored material usually butyl rubber lines the pond. The dark lining enhances absorption of the sun's radiation and prevents the salt from contaminating the surrounding soil and groundwater. As sunlight enters the pond, the water and the lining absorb the solar radiation. As a result, the water near the bottom of the pond becomes warm up to 93.3°C. Although all of the layers store some heat, the bottom layer stores the most. Even when it becomes warm, the bottom layer remains denser than the upper layers, thus inhibiting convection. Pumping the brine through an external heat exchanger or an evaporator removes the heat from this bottom layer. Another method of heat removal is to extract heat with a heat transfer fluid as it is pumped through a heat exchanger placed on the bottom of the pond. Another type of nonconvecting pond, the membrane pond, inhibits convection by physically separating the layers with thin transparent membranes. As with salt gradient ponds, heat is removed from the bottom layer. In figure 2 you can see an example of salt gradient solar pond.
Fig. 1 Salt Gradient Solar Pond.
III. ADVANTAGES AND DISADVANTAGES •
The approach is particularly attractive for rural areas in developing countries. Very large area collectors can be set up for just the cost of the clay or plastic pond liner.
•
The evaporated surface water needs to be constantly replenished.
•
The accumulating salt crystals have to be removed and can be both a valuable by-product and a maintenance expense.
•
No need of a separate collector for this thermal storage system.
IV. APPLICATIONS •
Salt production (for enhanced evaporation or purification of salt, that is production of ‘vacuum quality’ salt)
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•
Aquaculture, using saline or fresh water (to grow, for example, fish or brine shrimp)
•
Dairy industry (for example, to preheat feed water to boilers)
•
Fruit and vegetable canning industry
•
Fruit and vegetable drying (for example, vine fruit drying)
•
Grain industry (for grain drying) Water supply (for desalination)
•
Process heat
Studies have indicated that there is excellent scope for process heat applications (i.e. water heated to 80 to 90° C.), when a large quantity of hot water is required, such as textile processing and dairy industries. Hot air for industrial uses such as drying agricultural produce, timber, fish and chemicals and space heating are other possible applications. •
Desalination
Drinking water is a chronic problem for many villages in India. In remote coastal villages where seawater is available, solar ponds can provide a cost-effective solution to the potable drinking water problem. Desalination costs in these places work out to be 7.5paise per litre, which compares favourably with the current costs incurred in the reverse osmosis or electrodialysis/desalination process. •
Refrigeration
Refrigeration applications have a tremendous scope in a tropical country like India. Perishable products like agricultural produce and life saving drugs like vaccines can be preserved for long stretches of time in cold storage using solar pond technology in conjunction with ammonia based absorption refrigeration system. V. EXAMPLES OF SOLAR PONDS •
Bhuj Solar Pond
•
El paso Solar Pond
•
Pyramid Hill Solar Pond
A. Bhuj Solar Pond The 6000-square-metre solar pond in Bhuj, the first large-scale pond in industrial environment to cater to actual user demand, supplied totally about 15 million litres of hot water to the dairy at an average temperature of 75°C between September 1993 and April 1995. In figure 3 you can see the Bhuj solar pond.
Fig. 2 The Bhuj Solar Pond. www.giapjournals.com
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It was the first experiment in India, which successfully demonstrated the use of a solar pond to supply heat to an actual industrial user. But, sadly, the Bhuj solar pond, constructed by the Tata Energy Research Institute (TERI), today lies in disuse for want of financial support and government policy to help this eco-friendly technology grow. The Bhuj solar pond was conceived as a research and development project of TERI, which took over nine years to establish, to demonstrate the feasibility of using a salt gradient pond for industrial heating. The solar pond is 100 m long and 60 m wide and has a depth of 3.5 m. The pond was then filled with water and 4000 tonnes of common salt was dissolved in it to make dense brine. B. El Paso Solar Pond: The El Paso Solar Pond project is a research, development, and demonstration project initiated by the University of Texas at El Paso in 1983. It has operated since May 1986 and has successfully shown that process heat, electricity, and fresh water can be produced in the southwestern United States using solar pond technology.
Fig. 4 El Paso Solar Pond. The El Paso Solar Pond project began when the University of Texas at El Paso discovered an existing pond which has a 3350 square meter area and 3 meter depth located at Bruce Foods, a canning plant in northeast El Paso, Texas. In figure 5 you can see another view of El Paso Solar Pond.
Fig. 5 Closer View of El Paso Solar Pond.
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Over 90 graduate and undergraduate students have been involved in the project, performing tasks ranging from construction to applied research. In addition, numerous students have done projects related to the pond, gaining valuable experience in equipment design and construction, lab techniques, problem solving, instrumentation, and documentation. The solar pond provides a unique opportunity to do research in such areas as double diffusive convection, wind/wave interaction, flow in stratified fluids, and computer modeling. In addition, the state of the art equipment on site provides an excellent opportunity for energy efficiency studies, cost analysis, system studies, heat exchanger. C. Pyramid Hill Solar Pond: A consortium of RMIT University, Geo-Eng Australia Pty Ltd and Pyramid Salt Pty Ltd has completed a project using a 3000 square metre solar pond located at the Pyramid Hill salt works in northern Victoria to capture and store solar energy using pond water which can reach up to 80째C. In Figure 6 you can see the picture of this solar pond.
Fig. 6 The Pyramid Hill Solar Pond. Pyramid Salt will use the pond's heat not only in its commercial salt production but also for aquaculture, specifically producing brine shrimps for stock feed. It is planned in a subsequent stage of the project to generate electricity using the heat stored in the solar pond, thus making this local industry more energy self-sufficient. At the local level this will be a significant boost in an area with high unemployment and a depressed economy. VI. COST OF SOLAR PONDS As technology develops, the energy needs of communities increases. This energy need is provided from different energy sources known as traditional energy sources, such as coal, fuel oils, geothermal energy, hydraulic energy, and nuclear energy. These energy sources have some disadvantages. The first three of these energy sources have limited life times. Hydraulic energy is an insufficient energy source, and nuclear energy has some unsolved environmental and safety problems. Therefore, the researchers have condensed their studies on new alternative energy sources known as renewable energy sources. www.giapjournals.com
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These are biomass, biogas, wind energy, wave energy, hydrogen energy, and solar energy. Solar energy among these energy sources is the most abundant and considerable research is being carried out in this area. In figure 7 you can see a table which is comparing initial costs of different water heating systems.
Fig. 7 The Initial Costs of Several Water Heating Systems (1991 prices). Salinity gradient solar ponds, although not dramatically cheaper than other disposal methods, may still be a viable option especially in circumstances where the unit cost of power is very high or where access to a power grid is limited. Moreover, the actual cost of utilizing SGSPs may be lower than reported when other factors are taken into account, such as savings incurred by bypassing the waste disposal permitting process, the environmental savings associated with using a renewable fuel, or tax breaks that may be developed for facilities that use renewable fuels. REFERENCES: 1. http://edugreen.teri.res.in/explore/renew/pond.htm 2. http://edugreen.teri.res.in/explore/renew/solar.html 3. http://www.eere.energy.gov/consumerinfo/factsheets/aa8.html 4. http://en.wikipedia.org/wiki/Solar_pond
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VIBRATION ANALYSIS OF DRILLING OPERATION Amit S. Wani1, Gayatri S. Sagavkar2, Vaibhav K. Bhate3 Department of Mechanical Engineering, Fr.Conceiceo Rodrigues Institute of Technology, Vashi, Navi Mumbai, Maharastra, India 1 amitwn08@gmail.com, 2gayatrisagavkar@yahoo.com, 3bhatev@gmail.com
Abstract Vibrations are produced during any machining process. For drilling operation, analysis of these vibrations plays an important role in order to predict phenomenon of ‘chatter’. This paper emphasizes the analysis of vibration during drilling operation. The output results of analysis are useful to find out amplitude of vibrations produced with respect to drill size and spindle speed for standard rate of recommended feed/min. Analysis is quantified and tabulated as per available machining parameters of ‘THAKUR PELTER DRILLING MACHINE’ which is present in the Workshop of Fr. Conceiceo Rodrigues Institute of Technology, Vashi, Navi Mumbai. The optimum values of spindle speed and feed for maximium amplitude of transverse vibrations with respect to drill size are highlighted in the table and brought to the notice of Workshop Superintendent. The table of formulated results is displayed near this drilling machine. Keywords- Chatter, drilling operation I.
INTRODUCTION
Drilling Process is widely used in various types of industries. During drilling many a times, a phenomenon of ‘chatter’ of drill bit is observed. The reason for this ‘chatter’ is the vibrations produced during the drilling operation. The vibrations if produced by external parameters can be controlled by the methods of vibration isolation and carrying out periodic preventive maintenance of the machine. But, vibrations produced because of drilling itself i.e. due to spindle speed and feed cannot be controlled completely. So, such internal vibrations need to be avoided. As these vibrations depend upon the various machining parameters, calculation of vibrations can be done under different machining parameters. The results can be summarized and the critical values of machining parameters for which excessive vibration is produced can be obtained for a specific machine. This paper deals with the mathematical analysis of the drilling operation where vibrations due to ‘drilling’ are solely considered and values of critical machining parameters for ‘THAKUR PELTER DRILLING MACHINE’ are calculated. II.
NEED OF VIBRATION ANALYSIS DURING DRILLING OPERATION •
Phenomenon of ‘chatter’ is widely observed during drilling operation.
•
Vibration Analysis is the best solution to predict this complex phenomenon.
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•
Due to vibrations produced by drill dimensional accuracy of the hole gets affected. E.g. Transverse Vibration of 0.3 mm amplitude can result into enlarged hole of 0.6 mm excessive diameter.
•
Vibration during drilling operation affects the surface finish of the hole produced.
•
Assembly problems can be raised if the improper surface finished or enlarged holed workpiece is required to assemble with other.
•
Operational Problems can be raised if such part is installed on site e.g. tube and shell heat exchanger if the size of holes on baffles is enlarged then loosening of it may happen when fluid is flowing above them.
III.
SOURCES OF VIBRATION DURING DRILLING OPERATION
In Drilling Operation two types of vibrations are observed: A. External Vibrations
In drilling operation spindle of drill may vibrate because of the vibration developed by machine due to malfunctioning. These vibrations can be categorized as vibrations due to external parameters. Sources of external vibrations are as follows: •
Shaft Misalignment in spindle, motor, nut-bolts and transmitting elements viz., pulley or gear drives
•
Improper Foundation of machine
•
Loosen fasteners such as nut-bolts, clamps etc.
B. Internal Vibrations
Internal Vibrations in the drilling operation are produced due to ‘drilling process itself!. Internal vibrations are unavoidable as they occur because of internal characteristics of the system. Sources of Internal Vibrations are as follows:
IV.
•
Spindle Speed
•
Force exerted by workpiece in opposite direction to the drill motion
•
Resistive torque by induced by workpiece during material cutting
•
High feed rate
•
High Overhung of drill TYPES OF VIBRATIONS PRODUCED DURING DRILLING OPERATION
A. Vibrations in the drilling operation are produced in the two stages:
1) When the drill is rotating and approaching towards workpiece
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Fig 1 Drill has not entered into the work piece 2) When the drill is rotating and drilling a hole into the workpiece
Fig 2 Drill has entered into the work piece B. Following types of vibrations needs to be considered for drilling operation:
1) Free Vibration: Free vibration of the system helps to determine natural frequency of the system (Ď&#x2030;n).
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2) Forced Vibration: Forced vibrations are produced because of rotation of spindle. These vibrations have frequency of external excitation (ω) which is nothing but spindle speed in rad/sec. In forced vibration we have to consider force applied by the machine on the tool in no loading (Stage 1) and resistive force applied by the workpiece during drilling operation (Stage 2). V.
THEORY PART (MATHEMATICAL ANALYSIS)
A. Assumptions
1) Only the vibrations produced because of machining are considered. Effect of external vibrations is neglected as these vibrations can be controlled with various techniques. On the other hand internal vibrations which we are analysing can be controlled only by adopting safe machining parameters. 2) During analysing of particular type of vibration, only that type is assumed to be taking place. Effect of the other types is neglected for that analysis 3) We have considered cylindrical drill bit for the analysis as our scope is to find out the vibrations that are going to take place not the cutting operation which is being carried out. 4) During our analysis our main focus is concentrated on the transverse vibrations. This is because of the fact that the transverse vibrations produced during drilling operation are the main cause of the enlargement of the diameter of hole being produced beyond tolerance limit. B. Actual Procedure
1) For the drilling operation following three types are observed: •
Transverse Vibrations
•
Longitudinal Vibrations
•
Torsional Vibrations
Fig 3 Types of vibrations 2) Following procedure essential for Vibration Analysis of the drilling operation:
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o
Identification of the type of vibrations produced during machining operation
o
Determination of the factors affecting these vibrations
o
Applying concepts of the equilibrium to solve the problem
o
Finding out the forces that are exerted on the tool under various conditions
LIST OF SYMBOLS: d = Diameter of drill l = Length of drill E = Young’s Modulus σ = Tensile Strength τ = Shear strength ω = Frequency of vibration ωn= Natural Frequency ωt = Frequency with which spindle is rotating V = Tangential velocity of drill r = Radius of drill F = Force ξ = Damping ratio A = Amplitude of excitation B = Amplitude of support •
Longitudinal Vibrations
1) Free Longitudinal Vibration Analysis: Free longitudinal vibrations exist in the drill which are produced due to self-weight of the drill. These vibrations can be analysed with the help of the following formula: ωn=
rad/sec
ωn=
Hz
However these vibrations are not useful when we want to analyse the ‘chatter’ phenomenon of the drilling operation. Hence these vibrations are not considered during preparation of our table. 2) Forced Longitudinal Vibrations Analysis: Cases: 1) When the drill is rotating and approaching towards work piece Forced Longitudinal Vibrations do not exist when drill is approaching towards the work piece. It is because of the fact that as drill is approaching, no force acts on the drill in the upward direction. www.giapjournals.com
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Due to this, the vibrations of the drilling during approaching towards the workpiece can be neglected. 2) When the drill is rotating and drilling a hole into the work piece. When drill touches the work piece and starts cutting the material to produce the hole, the upward resistive force acts on the drill because of the tensile stress of the work piece material. When the material breaks during drilling the hole, its failure in the longitudinal direction can be considered as the compressive failure. The force exerted in the upward longitudinal direction during the failure of the workpiece can be calculated using the following formula: F= The amplitude of the forced longitudinal vibration can be computed using the formula given below[5]:
1
2ξ
ω ω
1
2ξ
ω ω
For our drilling machine we have considered no damping condition (since we want to consider the worst possible case) i.e. ξ
0 1 1
However, these longitudinal vibrations can be restricted with the help of restricting spring or suitable damping mechanism. These vibrations however, do not effect on the diameter of the hole produced. In Thakur Pelter Drilling Machine, which is used for very simple applications, these vibrations can be neglected since this machine is generally practiced to produce through holes only. •
Torsional Vibrations
1) Free Torsional Vibration Analysis: Free torsional vibrations exist in the drill which can be computed as follow:
ωn=
rad/sec
but, kt=
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I=mk2=
ωn=
m=ρ*volume of drill
m=ρ*
*l
ωn=
ωn=
rad/sec
These vibrations are useful to determine torsional natural frequency of the system (ωnt) This frequency is useful to obtain the forced natural torsional frequency of the system. 2)
Forced Torsional Vibration Analysis:
Cases: 1) When the drill is rotating and approaching towards work piece. No resistive force exerts on the drill in torsional direction when drill is approaching towards the work piece and hence the vibrations produced can be neglected. 2) When the drill is rotating and drilling a hole into the work piece. When drill enters into the work piece and starts cutting the material, torsional shear failure of the material takes place. Force exerted on the drill material during torsional failure of the work piece material can be computed as below: F= Where,
F=
T
Torque exerted is related with power in the following manner:
P=
π T
Torsional Vibrations are created because of the rotary motion of drill. These vibrations create resistive twisting moment on the drill and higher values of these vibrations may break the drill.
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Formula for finding amplitude of forced torsional vibration ( ) is given as: Considering value of damping to be negligible,
However as these vibrations do not affect in the transverse direction of motion which is responsible for the enlargement of the hole. Thus it is not considered in the calculation. •
Transverse Vibrations 1) Free Transverse Vibrations Analysis:
Fig 4 Free transverse vibrations in any body[2] The Vibrations in the drill in free state i.e. w/o rotation can be assumed as free transverse vibrations (as in case of compound pendulum) The Natural Frequency of the free transverse vibration (ωn) can be computed by using following formula: ωn
But, mass moment of inertia,
2 ωn
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4 g
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ωn=
. √
2) Forced Transverse Vibration Analysis Cases: 1) When the drill is rotating and approaching towards work piece When the drill approaches towards the work piece, the no external force on the drill except the force of vibration developed by the motor torque. And thus these vibrations can be neglected because there is no restricting force acting on the drill bit in the direction of the transverse vibration of the drill. 2) When the drill is rotating and drilling a hole into the work piece. When drill enters into the workpiece, the force is exerted by the workpiece material on the drill bit in the direction of the transverse motion of the drill. i.e. perpendicular to the axis of the drill. The analysis of this force can be understood from the following diagram:
Fig 5 Force analysis during transverse vibration The drill and work piece are considered to be attached with the help of the spring whose stiffness is ‘k’. Under equilibrium conditions, k = σ*v This is because of the fact when the drill transverses with the linear velocity ‘v’, the force is exerted on the drill in the direction of the transverse motion due to the stress induced in the material. Force is the resistive force applied by the work piece in the direction perpendicular to the axis of the drill. F=σ
π
* d *(feed/sec)
The forced frequency of transverse vibration can be computed with the help of following procedure: www.giapjournals.com
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N= rpm of the spindle ωt=
;
Fig 6 Free transverse vibrations in any body The relation between angular velocity and linear velocity of the drill cross section in the transverse direction can be given in the following manner: v=
ω
Now consider, the length of the drill oscillating at forced transverse frequency of ′ω′ in the following manner: ω= Now the amplitude of the transverse forced vibration when the drill enters into the workpiece can be computed by using the following formula[3]:
1
2ξ
ω ω
For our drilling machine we have considered no damping condition (since we want to consider the worst possible case) i.e. ξ
0 1 1
IV.
PRACTICAL APPROACH
SAMPLE CALCULATIONS (For N=92 rpm, feed = 4.6736 mm/min, drill diameter =3.175mm DATA: d=0.00317m l=0.150m E=4.461*109N/m2 www.giapjournals.com
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σ=420*106N/m2
[4]
TO FIND OUT: ω,ωn,K,F,A SOLUTION: For 92 rpm ωt= 2*Π*N/60 = 2*Π*92/60 =9.63rad/sec.
Fig 7 Chart prepared for the workshop
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ωn=3.835/√ =3.835/√0.150 =9.901rad/sec. F=Π*d*(feed/sec)*σ [1]
Feed/sec=((feed/rev)*N)/60 =(0.0508*0.001*92)/60 =7.789e-5m/sec F = Π*0.00317*7.789e-5*420e6 =329.84N/sec v = ωt*r =9.63*0.00317/2 =0.015m/s K = σ*v =420e6*0.015 =63e5N/m ω = v/l = 0.015/0.150 = 0.1rad/sec ω/ωn = 0.1/9.901 =0.01 A = (F/K)/(1-(ω/ωn)2) = (329.84/63e5)/(1-0.012) = 0.051mm A=0.051 mm
Fig 8 Photograph with Workshop Superintendent near the Thakur Pelter Drilling Machine along with the chart displayed
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V.
CONCLUSIONS
We used the straight and simplified approach in the analysis of the vibrations produced during drilling operation on “THAKUR PELTER DRILLING MAHCINE”. We arrived to the conclusion that the “chatter” phenomenon is produced due to the transverse vibrations of the drill, which adversely affect the assembly problem. Longitudinal vibration only changes the length of blunt hole and does not affect the though hole. Torsional vibration leads to the removal of the material from the workpiece with the help of chisel edge and flanks on drill, but does not affect the dimensions of the hole. This report is the best example to show that how the theory knowledge gained in the academic curriculum can be effectively applied to the practical scenario. ACKNOWLEDGMENT We are thankful to R.G.I.T., Andheri, for giving us this platform to think over our regular academic curriculum. During preparation of this paper, we got various guidelines from our professors in the college, particularly; we want to thank Prof. Girish Dalvi and Prof. Shamim Pathan for their technical support in our work. We are equally thankful to workshop superintendent Mr.Rajesh and workshop supervisor Mr.Moreshwar for their support in our practical work. REFERENCES [1] Erik Oberg and Franklin D Jones, “Machinery’s Handbook”(28th Edition). [2] F. B. Sayyad, “Mechanical Vibration”,Tech-max Publications. [3] V. P. Singh,“Mechanical Vibration”,Dhanpat rai Publication. [4] S. K. Hajra choudhury, A. K. Hajra choudhury and Nirjhar Roy, “Elements Of Workshop Technology Volume -2 Machine Tools” [5] S. S. Rao, “Mechanical Vibrations ”,Pearson publication [6] Mr. Muhammad Munawar, “Optimization of Surface Finish by Considering the Effect of Vibration in Machining Operations” [online].
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DESIGN AND ANALYSIS OF RISER FOR SAND CASTING C. M. Choudhari, Nikhil S. Dalal, Akshay P. Ghude1, Pratik P. Sankhe, Ashutosh M.Dhotre Mechanical Department, Fr.C.Rodrigues Insitute of Technology, Vashi, Navi Mumbai, India 1
akshayghude22@yahoo.com
Abstract Casting is one of the earliest metals shaping method known to human beings. It is one of the cheapest methods for mass production of any part and can be effectively used to make complex shaped parts which are not easy to manufacture by other production process. Casting process is subjected to many defects and it is necessary to eliminate them. One of the main defects in castings is â&#x20AC;&#x153;Shrinkage Cavityâ&#x20AC;?, which can be eliminated by attaching a Riser to the casting. This paper describes the parameters to be considered while designing a Riser of an optimum size to get higher Casting Yield. Theoretically designed model has been analyzed thermally in ANSYS 12.0 simulation software to ensure that shrinkage cavity is completely eliminated from casting. I.
INTRODUCTION
CASTING is a metal shaping process by pouring the molten metal into a mould and allowing it to solidify. The resulting product can virtually have any configuration (pattern) the designer wants. Casting consists of various parts like cope, drag, pattern, sprue, runner, ingates, riser, etc. The process consists of design, solidification, shake out, finishing and heat treatment. Although casting is one of the cheapest methods it is associated with many defects like shrinkage cavity (hot spot), cold shuts, misrun, etc. In order to understand how a shrinkage cavity develops consider a mould of cube. Figure (a) shows a cube which is completely filled with liquid metal. As the time progresses, metal starts loosing heat through all the sides and as a result starts freezing from all the sides, equally trapping the liquid metal inside, as in figure (b). But further solidification and subsequent volumetric shrinkage and metal contraction due to change in temperature causes formation of void, as shown in figure (c). The solidification when complete, finally results in shrinkage cavity, as in figure (d). An optimal design of riser will help in reducing hot spots formation/ void formation/ shrinkage cavity by ensuring that molten metal can readily flow into the casting when the need arises. To eliminate the defect of hot spot riser is used in casting. It helps to fill in the cavity formed inside the casting.
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Figg. 1.Formatioon of shrinkaage cavity [1]. Wheneverr the cavity iss formed insidde the castingg the molten metal m from thhe riser movees to that spacce and fills the caavity. In ordeer to achieve this, t the dimeensions of the riser should be b optimum so s that the meetal in the riser solidifies s afterr the casting. The mainn parameter th hat controls thhe solidificatiion time of a casting is thee casting moddulus. The am mount of heat coontent in a sysstem is determ mined by its volume v & thee rate at whicch it loses heaat is determinned by its surfacee area [2]. Castting modulus is a ratio of volume v of a casting c to its surface s area. II.
O OBJECTIVE
The formaation of hot spot s inside thee casting is a major defectt in metals likke aluminum and steel. In order to increasse the yield off the casting it i is necessaryy to optimize riser design which will allso ensure rem moval of hot spoot from the caasting. Riser will w ensure thhat the moltenn metal will move m into thee casting wheenever it is desireed. The main objective of our project iss to design a riser r having higher h value modulus m that is, i of solidificcation c This will ensure thhat metal willl remain in the t molten staate inside thee riser time as coompared to casting. until soliddification of th he casting is completed. c III.
T THEORETIC CAL STUDY Y
Initially for f the case study a simpple casting was w designed with its variious parts. Casting is a simple rectangulaar plate of alu uminium. Thee size of the plate p is 200mm m Ă&#x2014; 200mm Ă&#x2014; 40 mm as shhown in figurre.
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Fig. 2.Geometry of Casting For design of patter following allowances were considered: Shrinkage allowance[3]: For 200 mm: 2.6 mm For 40 mm: 0.52 mm Draft allowance = 1.5° (on vertical sides only) Machining allowance = 2 mm on each side Tolerance = ¹ 1 mm Details regarding the model: Total surface area = 120835.92 mm2 Total volume = 1848597.301 mm3 Modulus = 15.29 mm. Solidification time = 14.36 min. Weight of the casting = 4.4089 kg Design of gating system: Pouring time =17.363 sec Choke area = 98.46 mm2 Sprue bottom diameter = 12 mm Sprue top diameter = 15 mm Sprue height = 42.5 mm Total area of ingates= 452.38 mm2 www.giapjournals.com
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The design of riser was done using Caine’s method[1]. The height of riser was assumed to be 70 mm and the height of riser neck was assumed to be 10 mm. Following formulae were used for finding the dimensions of casting. Volume of the riser = πr2h Surface area = πr2+2πrh Freezing ratio (X) = (Ac / Vc) / (Ar / Vr) Where, Ac= Area of casting Vc = Volume of casting Ar = Surface area of riser Vr = Volume of riser Y = Vr / Vc X = ((a) / (Y-b))-c For aluminium: a=0.1 b=0.03 c=1 The riser diameter by Caine’s method is 55.244 mm. For actual practice, Riser Diameter, Dr = 60 mm. According to a research paper on optimum design of riser[8], Dn = 0.35 × Dr Yield of feeder = (Vc) / (Vc+Vf+Vn) = 90.176 % Yield of casting = (Wc)/ (Wg+ Wf) = 82.18 % Where, Wc = weight of casting Wg = weight of gating elements Wf = weight of feeding elements IV.
SIMULATION
Simulation of casting was done to serve two main purposes. First, it was used to find the location of hot spot. Second, it was used to find the optimum dimension of riser so that hot spot shifted into the riser[4]. The effect of sleeve and air gap was also studied using simulation. These studies were done using both linear and quadratic elements and both free and mapped mesh was used. The following properties were used for sand during the entire simulation:
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Conductivity
0.519 W/m K
Specific Heat
1172.304 J/kg K
Density
1495 kg/m3
The following properties were used for aluminium during the entire simulation:
TABLE II PROPERTIES OF ALUMINIUM Temperature
Conductivity [6]
Enthalpy [7]
273K
234.43 W/m K
0 J/m3
820K
216.01 W/m K
933K
90.975 W/m K
1043K
94.786 W/m K
1.5533 × 109 J/m3 1.7769 × 109 J/m3 2.0574 × 109 J/m3
A. Identification of Hot Spot The top view of the casting was simulated in ANSYS 12 software. At the end of simulation the last solidifying region was obtained. 1) Simulation using Linear Elements For this study, PLANE 55 was used as the linear element. PLANE55 can be used as a plane element or as an axisymmetric ring element with a 2-D thermal conduction capability. The element has four nodes with a single degree of freedom, temperature, at each node. The top view was modeled for free and mapped mesh as shown in the figure.
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Fig. 3.Modeling of Casting with Free Mesh.
Fig. 4.Modeling of Casting with Mapped Mesh.
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Then, the material properties were specified followed by meshing of geometries. The meshed geometries with free and mapped mesh are shown below.
Fig.5 Free Mesh of Casting
Fig. 6 Mapped Mesh of Casting www.giapjournals.com
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After meshing, convective load was applied on the outer boundaries of the casting. The ambient temperature was assumed to be 303 K. The initial temperature of molten aluminium was assumed 1043 K and the initial temperature of sand was assumed to be 303 K. The temperature time plot of various nodes for free and mapped mesh was obtained as shown below:
Fig. 7. Temperature Time Plot for Free Mesh
Fig. 8. Temperature Time Plot for Mapped Mesh
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The animation was run for 1 hour and the location of hotspot for free and mapped mesh was obtained as shown below:
Fig. 9. Location of Hot Spot in Free Mes
Fig. 10. Location of Hot Spot in Mapped Mesh 2) Simulation using Quadratic Elements For this, study PLANE 77 and PLANE 35 were used as the quadratic elements. Same steps were followed for simulation using quadratic elements. The results obtained after the simulation showed that the minimum temperature in the entire casting drops below ambient temperature. www.giapjournals.com
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Fig. 11. Temperature Time Graph for PLANE 77 element
Fig. 12. Temperature Time Graph for PLANE 35 element This is not possible as the minimum temperature specified during simulation was ambient temperature. Consequently, these results were not taken into account during further simulations.
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B. Finding Optimum Riser Dimensions Once, the location of hot spot was identified, the next objective was to find the optimum riser dimensions. For this purpose, following dimensions of riser were considered. TABLE III RISER DIMENSIONS Sr. No. Riser Diameter Riser Height Neck Diameter Neck Height 1
30 mm
70 mm
10.5 mm
10 mm
2
40 mm
70 mm
14 mm
10 mm
3
50 mm
70 mm
17.5 mm
10 mm
4
60 mm
70 mm
21 mm
10 mm
The above risers were first modeled in ANSYS. These models were then meshed using PLANE 55 element and free mesh. The animation of these models yielded the following results.
Fig. 13. Location of Hot Spot for Riser with Diameter 30
Fig. 14. Location of Hot Spot for Riser with Diameter 40 www.giapjournals.com
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Fig. 15. Location of Hot Spot for Riser with Diameter 50
Fig. 16. Location of Hot Spot for Riser with Diameter 60 It is clear from the above figures that the hot spot shifts into the riser for diameter of 60 mm. C.Effect of Sleeve on Riser Diameter An insulating sleeve was used around the riser to slow down the rate of transfer of heat from the riser. A sleeve of 5 mm thickness was used around the riser of 50 mm diameter. The result of this simulation is shown below:
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Fig. 17. Location of Hot Spot for Riser with Sleeve As seen from the above figure, sleeve helps in maintaining the riser hot for a longer time. As a result, a riser of diameter 50 mm can be used instead of 60mm. this helps in increasing the casting yield. D. Effect of Air Gap The modeling of air gap in casting was done as follows:
Fig. 18 Modeling of Air Gap After the modeling was completed the casting was meshed using free mesh. An air gap is formed only after aluminium solidifies. As aluminium solidifies at 933 K, the simulation was run from 933 K. The temperature time plot for various nodes was obtained as shown below:
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Fig. 19. Temperature Time Plot for Casting with Air Gap From the above graph, it is seen that the maximum temperature at the end of simulation is 737.711 K. For comparison, a similar model without air gap was made and the simulation was run from 933 K. The temperature time plot for various obtained is as follows:
Fig. 20. Temperature Time Plot for Casting without Air Gap www.giapjournals.com
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From the above graph, it is seen that the maximum temperature at the end of simulation is 716.708 K.
V.
ACTUAL TRIALS
The values obtained from theoretical calculations for design of pattern, gating system & riser were used to manufacture casting. The casting having riser diameter equal to 60 mm was found to be defect free. Also a defect free casting was obtained when a sleeve of 50mm diameter was used.
Fig. 21 Plate casting VI.
CONCLUSION
•
ANSYS is a good tool to carry out solidification simulation.
•
The optimized Riser dimensions were validated by simulation results and actual trials.
•
Using sleeve as a feed aid helped in reducing riser dimensions there by increasing the Casting Yield.
•
Simulation using other Thermal Solid MID-SIDE NODE Elements (Plane-35 & Plane 77) yielded absurd results & thus cannot be used for Transient Thermal Analysis in ANSYS.
•
Results of Simulation of casting solidification with air gap between Sand & Metal prove that air acts as an insulator for heat transfer, but the effect can be neglected as there is no appreciable difference between the simulation results when air gap was not considered.
REFERENCES [1] P.N.Rao, “Manufacturing Technology”, Tata McGraw-Hill Education, New Delhi, 2008. [2] John Campbell and Richard A Harding, “Solidification Defects in Casting”, IRC in Materials, The University of Birmingham. [3] PSG College of technology, “Design Data Book”, PSG College of Technology, Coimbatore, 2005. www.giapjournals.com
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[4] Dr. Mohammad Al-Tahat, “Metal Casting and Foundry”, Jordan University, course no. 906412. [5] D. Joshi and B Ravi, “Classification and Simulation based Design 3D Junctions in Castings”, American Foundry Society, 2008. [6] C.Y. Ho, R.W.Powell and P.E.Liley (1972) , “J. Phy. Chem. Ref. Data, vl”. [7] B.J. McBride, S. Gordon and M.A.Reno (1993), “NASA Technical Paper 3287”. [8] T. Nandi, R. Behera, S. Kayal, A. Chanda and G. Sutradhar, “Optimization of Riser size of Aluminium alloy (LM6) castings by using conventional method and computer simulation technique”, International Journal Of Scientific & Engineering Research, Volume 2, Issue 11, November-2011
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A GENERALIZED CODE FOR COMPUTING CYCLIC REDUNDANCY CHECK Debopam Ghosh, Arijit Mitra, Arijit Mukhopadhyay, Aniket Dawn, Devopam Ghosh Electronics and Communication Engineering, Heritage Institute of Technology, Kolkata, India debopamghosh2010@gmail.com, arijitmitra.mitra@gmail.com, arijit2758@gmail.com, aniketdawn@hotmail.com , dave1904@gmail.com
Abstract This paper focuses on developing a generalized CRC code where the user can vary the size of the generator polynomial [1] such as 9 bits (CRC-8), 17 bits (CRC-16), 33 bits (CRC-32), 65 bits (CRC-64). The working of the code has been shown taking an example and the resulting simulations obtained are shown.
I.
INTRODUCTION:
Cyclic Redundancy Check [2] is a method adopted in the field of communication to detect errors during transmission through the communication channel. The data transmitted can be of any size depending on the type of data being transmitted. In this paper, we have designed a VHDL code which demonstrates how the CRC process works on a codeword whose length can be changed by the user based on his requirements and the necessary simulations can be carried out to verify the results. Cyclic Redundancy Check (CRC) is an error detecting code in which a transmitted message is appended with a few redundant bits from the transmitter and then the codeword is checked at the receiver using modulo-2 arithmetic for errors. The message is then transmitted from the encoder and is received by the receiver where a CRC check is carried out. This process helps to determine any errors in transmission through the transmission channel. This entire process is demonstrated using Very high speed Integrated Circuit Hardware Description Language (VHDL)[3]. VHDL is a hardware description language used in electronic design automation to implement designs in systems such as field-programmable gate arrays. All the statements are executed concurrently in VHDL. II.
PROCESS OF CRC IMPLEMENTATION:
Figure 1: Method of polynomial detection
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The method of determining the polynomial is as follows: Each value is considered as the coeffiecient of a particular term which is an exponent of x. The rightmost bit is considered as the 0th, the next is the 1st, then 2nd and so on. For example, 1011 would mean a polynomial of [(1*x0)+(1*x1)+(0*x2)+(1*x3)]=x3+x+1 (starting from rightmost).
Figure 2: Block Diagram of Receiver and Sender
Figure 3: Bitwise Representation of the Encoder and Decoder Considering a n-bit message is being transmitted and k is the number of data bits. According to the CRC process, a particular polynomial has to be chosen and this polynomial is known as the divisor polynomial. The message is treated as the dividend and the divisor polynomial is used to divide the message polynomial to generate a remainder. The method used for this purpose is known as modulo-2 division[4]. In modulo â&#x20AC;&#x201C; 2 division, carry bit in addition and borrow bit in subtraction generated from one particular bit is not carried forward to the next bit. In other words, for subtraction process simple XOR can perform the necessary operations. The message is augmented with (n-k) number of 0â&#x20AC;&#x2122;s. Then the modulo-2 division is carried out and the remainder of (n-k) bits is generated. This remainder then replaces the (n-k) 0â&#x20AC;&#x2122;s at the end of the message sequence and it is then transmitted.
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Fig 4: Division in CRC Generator At the receiver, the data bits appended with the remainder is received as the dataword. The dataword is divided by the same generator polynomial to generate another remainder polynomial. If the polynomial generated is 0, then it is considered as error free. Otherwise the received message contains errors. The entire process is divided into two broad parts; ENCODER and DECODER. All the operations related to transmission of the dataword are carried out in the encoder while the checking operations are carried out in the decoder. For this reason, the encoder is known as CRC Generator and the decoder is known as CRC Checker.
Fig 5: Division in CRC Checker with correct and erroneous codeword
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Fig 6: Example of a CRC Division using Polynomial
III.
ALGORITHM:
CRC GENRATION: Step1: Input the message to be sent through port a. Step2: Input the CRC polynomial/divisor through port b. Step3: Define the output port x,t (x-> stores the redundant bits, t-> stores the message + redundant bits). Step4: Begin process and declare the required variables- u,v,w,y,i,j. Step5: In the variable v store the message bits followed by (n-1) 0â&#x20AC;&#x2122;s. Step6: w= first n bits of v and u=CRC polynomial/divisor. Step7: If the MSB of w is 1 then w = w xor u (divisor) else w remains unchanged. Step8: Left shift w and discard the MSB. Step9: The next bit of v (in case of 1st iteration (n+1)th bit from the beginning,2nd iteration (n+2)th from beginning etcâ&#x20AC;Ś) becomes the LSB of w. Step10: Repeat steps 7-8-9 till the end of v is reached (there will be a single iteration after LSB of v is be added to w). Step11: Port x(redundant bits/remainder) = first (n-1) bits of w. Step12: Port t = message bits + redundant bits. CRC CHECK: Step1: Input the received bits and CRC polynomial through port a and b respectively. Step2: As before follow the steps to generate the remainder and store in port x. www.giapjournals.com
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Step3: If the remainder is all 0’s then the received message is error free and t=received bits- redundant bits. Step4: If remainder is not all 0’s then there is an error and the message is discarded so t= all 0’s. CRC GENERATOR VHDL CODE library IEEE; use IEEE.STD_LOGIC_1164.ALL; use IEEE.STD_LOGIC_ARITH.ALL; use IEEE.STD_LOGIC_UNSIGNED.ALL;
package my_package is constant m:integer:=8; constant n:integer:=4; end my_package;
library IEEE; use IEEE.STD_LOGIC_1164.ALL; use IEEE.STD_LOGIC_ARITH.ALL; use IEEE.STD_LOGIC_UNSIGNED.ALL; use work.my_package.all;
entity crc_new is Port ( a : in STD_LOGIC_VECTOR (m-1 downto 0); ---message bits b : in STD_LOGIC_VECTOR (n-1 downto 0);
---crc polynomial
clk : in STD_LOGIC; x : out STD_LOGIC_VECTOR (n-2 downto 0); ---redundant bits t : out STD_LOGIC_VECTOR (m+n-2 downto 0));
---message with redundant bits
end crc_new;
architecture Behavioral of crc_new is begin process(clk) variable v:std_logic_vector(m+n-2 downto 0); variable u:std_logic_vector(n-1 downto 0); variable w:std_logic_vector(n-1 downto 0); www.giapjournals.com
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variable y:std_logic_vector(n-1 downto 0); variable i,j:integer:=0; begin v(m+n-2 downto n-1):=a(m-1 downto 0);
for j in n-2 downto 0 loop v(j):='0'; end loop; u:=b; w:=v(m+n-2 downto m-1); for i in m-1 downto 0 loop if(w(n-1)='1') then w:=w xor u; else null; end if; y:=w; w(n-1 downto 1):=y(n-2 downto 0); if(i=0) then w(0):='0'; else w(0):=v(i-1); end if; end loop; x<=w(n-1 downto 1); ---- redundant bits t(m+n-2 downto n-1)<=a; t(n-2 downto 0)<=w(n-1 downto 1); end process; end Behavioral;
RTL SCHEMATICS
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Fig 7: Black Box view of C RC Generator
Fig 8: Internal connections of CRC Generator
CRC CHECKER VHDL CODE library IEEE; use IEEE.STD_LOGIC_1164.ALL; use IEEE.STD_LOGIC_ARITH.ALL; use IEEE.STD_LOGIC_UNSIGNED.ALL;
package my_package is constant m:integer:=8; constant n:integer:=4; end my_package;
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library IEEE; use IEEE.STD_LOGIC_1164.ALL; use IEEE.STD_LOGIC_ARITH.ALL; use IEEE.STD_LOGIC_UNSIGNED.ALL; use work.my_package.all;
entity crc_new is Port ( a : in STD_LOGIC_VECTOR (m-1 downto 0); ---message bits b : in STD_LOGIC_VECTOR (n-1 downto 0);
---crc polynomial
clk : in STD_LOGIC; x : out STD_LOGIC_VECTOR (n-2 downto 0); ---redundant bits t : out STD_LOGIC_VECTOR (m+n-2 downto 0));
---message with redundant bits
end crc_new;
architecture Behavioral of crc_new is
begin process(clk) variable v:std_logic_vector(m+n-2 downto 0); variable u:std_logic_vector(n-1 downto 0); variable w:std_logic_vector(n-1 downto 0); variable y:std_logic_vector(n-1 downto 0); variable i,j:integer:=0; begin v(m+n-2 downto n-1):=a(m-1 downto 0);
for j in n-2 downto 0 loop v(j):='0'; end loop;
u:=b; w:=v(m+n-2 downto m-1); for i in m-1 downto 0 loop if(w(n-1)='1') then www.giapjournals.com
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w:=w xor u; else null; end if; y:=w; w(n-1 downto 1):=y(n-2 downto 0); if(i=0) then w(0):='0'; else w(0):=v(i-1); end if; end loop; x<=w(n-1 downto 1); ---- redundant bits t(m+n-2 downto n-1)<=a; t(n-2 downto 0)<=w(n-1 downto 1); --- total message end process; end Behavioral; RTL SCHEMATICS
Fig 9: Black Box of CRC Checker
Fig 10: Internal connections of CRC checker www.giapjournals.com
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IV.
SIMULATION:
Fig 11: Simulation result of CRC generator waveform
Different input datawords have been sent at different instants of time. In the first instant, “10010011110”, at the next instant ‘10010100111” and at the next instant, ‘10010101010” is transmitted from the encoder. The different values like 1182, 1191, 1194 etc represent the input dataword in decimal.
Fig 12: Simulation result of CRC check waveform www.giapjournals.com
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At the decoder, we see that the remainder (t) is equal to a string of 0’s, showing that if the received codeword (a) is same as that of the transmitted codeword (t) in the encoder, there is no error. Here, the received codeword has been intentionally made to be equal to the transmitted codeword to show a successful transmission.
V.
CONCLUSION:
In this paper, the process of CRC generation and checking has been discussed in detail. The methods applied to detect an error during transmission has been shown using simulation in VHDL. However CRC has some limitations: •
CRC is only an error detecting method. It does not correct the errors.
•
The divisor polynomial should be chosen carefully. The divisor polynomial has to be a multiple of (x+1). If any random polynomial is chosen then it may result into wrong calculation of the remainder (CRC).
REFERENCES: 1. Cyclic Redundancy Code (CRC) Polynomial Selection For Embedded Networks By Philip Koopman and Tridib Chakravarty 2. CRC Cyclic Redundancy Check Analysing and Correcting Errors By Prof. Dr. W. Kowalk 3. VHDL basics By Raunak Ranjan 4. http://en.wikipedia.org/wiki/Cyclic_redundancy_check
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ADAPTIVE WEB BROWSER Akshay Parashar1, Manish Mali2, Ranjeet Kumar3, Prof.SaritaAmbadekar Department of Computer Engineering, K.J.Somaiya Institute of Engineering and Information Technology, Sion (E) Mumbai-400 022 akshay.parashar2@gmail.com, manishmali57@gmail.com,ranjeetkr1991@gmail.com, saritaambadekar@yahoo.co.in
Abstract Web browser play important role in World Wide Web (WWW). We go through different website and invest enough time searching relevant URL. The project deals with making a browser that will assist a person to find relevant information satisfying long term recurring goals rather than short term goals and describe our research on learning browser behaviour model for predicting the current information need of web user. Depending upon the user sequence of browsing behaviour it indicates the degree to which page content satisfies user’s need. Thus one’s search experience may be used to help the next users to reduce their searching effort. So, through more and more searching greater experience will be gained by browser. We deploy extensive use of machine learning for the browser to learn user’s behaviour. By such model the searching ability of browser becomes more efficient and faster thus resulting in an intelligent and adaptive web browser. Key Words – Machine learning, WWW I. INTRODUCTION While the World Wide Web contains a vast quantity of information, it is often difficult for web users to find theinformation they are seeking. A more usefulsystem would not impose this requirement on the user, butinstead would predict the exact query to return a page tosatisfy the user’s current information needs. We call such apage an information content page, or “IC-page” for short,and name such a query as “machine query” since it is notproduced by the human being.Suggestions using a set of “browsing features” to predict the user’s current information need, which can then be usedto find relevant web pages by launching a Web crawler orquerying a search engine. For the problem of predicting clicked hyperlink, thesimplest solution would be to have a binary-. In this way some existing text-learning methodscan be used. In this case all the hyperlinks clicked bythe user are considered positive examples. This partially alreadycaptures user interests. However, in many cases userdidn’t click on a hyperlink just because the lack of timeand also probably didn’t find interesting all the visiteddocuments.This approach could be adapted for the problem ofsuggesting interesting hyperlinks, if we are prepared toaccept that all the documents visited by the user wereinteresting to the user and that un-clicked (or random)documents are uninteresting. Of course, the www.giapjournals.com
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simple solutionto that would be to ask the user for documentrating but we do not want to put additional work tothe user. II. EXISTING SYSTEM Currently, most users are employed withinformation retrieval techniques in the form of popularsearch engines to find useful pages. While such techniqueshave been quite helpful, they still require a user to provideexplicit input. Search engines can only work if the usershave intuitions about what keywords they should use (i.e.,which words will cause the search engine to produce theinformation the user is seeking). But sometimes the user isnot aware of her explicit need, or cannot figure out the rightquery to locate the exact pages that she/he wants. III.METHODOLOGY The proposed system has the following process flow: Start
Enter Keyword
If keyword found
Store keyword in DB
Learning Process
Fetch result from search engine
Fetch result from search engine
Retrieval method
Display result
Merge
Display result
SEARCHING FLOW PREDICTING CLICKED HYPERLINK www.giapjournals.com
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This approach could be adapted for the problem of suggesting interesting hyperlinks, if we are prepared to accept that all the documents visited by the user were interesting to the user and that unclicked (or random) documents are uninteresting. PREDICTING INTERESTING HYPERLINK Predicting interesting hyperlinks can be performed by predicting clicked hyperlinks as described in Section. Noise in the class value can be reduced by learning from the clicked hyperlinks (positive examples) only. This would in our case require solving at least two additional problems: (1) Finding an appropriate feature selection method, say the basis for hyperlinks to consider can be the clicked hyperlinks(positive examples) and (2) Proposing a suitable result evaluation. Algorithms like association rule, naive bayes, k-means can be used to perform learning. Additionally, features like number of clicks (how many times a hyperlink is clicked corresponding to a particular keyword),time duration (time spend on a particular hyperlink),can be taken into account. IV. ALGORITHM Step1: Start. Step2: Get keyword from user. Step3:If keyword exists then retrieve, from database the relevant links using retrieval module and also from search engine. Step4: If not then save keyword in database and display result using search engine. Step5: Save clicked hyperlinks corresponding to the keyword clicked by user(positive links). Step6: Apply Machine Learning methodology to database to generate interesting hyperlinks pertaining to IC page. Step7:Display theresults to user. V. FUTURE SCOPE To further help users browsing the Web, a profile can be induced for each user independently of other users. This profile can be further used to compare different users and to share knowledge between them. In order to secure the privacy, only knowledge and not the user identity can be exchanged or even this cooperation could apply only for users that explicitly agreed to take part in knowledge sharing. On the other hand, some users might be interested in â&#x20AC;&#x2122;making friendsâ&#x20AC;&#x2122; with similar users and join the list of users whose identity (eg. e-mail) is reviled to similar users from the list. This sharing of knowledge is related to collaborative approach to intelligent agents design and methods used in multiagent systems. A way of cooperation between different users using the same system for user customized Web browsing is on the model induction level. Namely, even though each user has a separate user profile, they have a similar form. If we could infer from the user profiles some higher www.giapjournals.com
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level knowledge that is independent of a specific set of documents, that knowledge could be shared between users. For instance, if we have given some background knowledge, find which part of a given background knowledge is frequently used in different models (which higher-level attributes are useful). That would be especially valuable for new users, where only a small set of documents is available for the model induction. Sharing knowledge between different users of the system is out of the scope of this paper. Also, the results obtained from various search engines can be categorised to distinguish and validate the effectiveness of information retrieval methodology used by them. This partially can be used as a parameter by search engine to make relevant improvement in their searching algorithm. VI. CONCLUSION The paper proposes the methodology that helps user to retrieve IC page but only through long term machine learning experience of browser. Distinguishing feature of proposed system is that •
The browser has a dedicated database to it and can provide user hyperlinks in offline mode.
•
It reduces the dependency of user on search engines gradually gaining autonomy as an assistant to help user.
•
Since the processing of data takes place at client side the user is provided with relevant hyperlink faster independent of server to which it seeks link.
•
Apart from browser’s suggested links the user is not kept from results of search engine.
REFERENCES [1]Adaptive Web Browser: An Intelligent
Browser Md. Forhad Rabbi, Tanveer Ahmed, Anindya
Roy Chowdhury, Md. Ran-O-Beer Islam Department of Computer Science & Engineering Shah Jalal University of Science & Technology Sylhet, Bangladesh [2]Identifying Machine Query for an Intelligent Web Browser System Tingshao Zhu, Graduate University ofChinese Academy of SciencesBeijing, China XinguoXu, National Computer System EngineeringResearch Institute of ChinaBeijing, China Guohua Liu, Department of Computing ScienceUniversity of AlbertaEdmonton, Canada [3] Machine learning for better Web browsing DunjaMladeni, Dept. of Intelligent Systems, J.StefanInstituteJamova 39, 1000 Ljubljana, Slovenia [4]A Platform for Large-Scale Machine Learning on Web Design ArvindSatyanarayan, SAP Stanford Graduate Fellow Dept. of Computer Science Stanford University 353 Serra Mall Stanford, CA 94305 USA Maxine Lim, Dept. of Computer Science Stanford University 353 Serra Mall Stanford, CA 94305 USA Scott R. Klemmer, Dept. of Computer Science Stanford University353 Serra Mall Stanford, CA 94305 USA
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AUTOMATIC FARMING SYSTEM 1
Kailas Adhav, 2Abhilesh Wankhede Vidyavardhini’s College of Engineering and Technology, Vasai Road (West) 1 kailasadhav02@gmail.com, 2wabhilesh10@gmail.com
Abstract Since Olden times man has been cultivating and depending heavily on the plant and crops to arrange for the staple food. To do this he had to toil and severe with labor. As the technology advances people wish for more and more comfort, reliability and fast operation. India is the farmer’s country and major part of the revenue is generated out of the agriculture industry Keeping the above ideology in mind
this project propose to design a unit with following
features:1.ploughing 2.seedsowing 3.cutting etc. This study develop an Energy Saving Automatic Farming System with two unit User unit (remote control) & Solar Powered Tractor Unit. From user unit i.e. Wireless remote it gives instruction to the tractor unit to perform various task such as plugging, seed sowing, cutting etc The required power supply for performing various task is obtained from solar panel using tracking and trapping system to obtain maximum solar energy. For automation of tractor unit it uses memory mapping which will be performed by microcontroller in embedded c using Kiel software.
I.
INTRODUCTION
The conventional sources of energies are limited & are nonrenewable source. Looking at today’s use of energy, these sources are not going to last for more than 30 years from now. What will the world do, after these sources are exhausted? The ultimate source of energy then will be non-conventional sources of energy. These sources are renewable type. As much as you use, it will always remain. Sun will never stop rising/ shinning. In the twenty-first century, consumption of energy has increased on account of technological progress and population explosion. Hence scientist began to express the fear that deposits of conventional fuels would be depleted in the near future the possibility of the exhaustion of the sources of fuels is known as the ‘energy crises. The average solar energy radiated on earth is 1.36 kWh (kilowatt hour) per square meter. This energy is equal to the energy that can be obtained from 12 lakh crore tons of coal & is 20 times the amount of energy that can be obtained from the total coal deposits available on the Earth So this project “automatic farming system” which will harness the solar energy and will be use for agriculture purpose in a unique and innovative way. A. What is Robot? A robot can be defined as a reprogrammable, multifunctional manipulator which is designed to move material, parts, tools, or specialized devices through various programmed motions to perform a variety of tasks. B. Features of Project: The designed solar powered tractor has following features: www.giapjournals.com
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1. It has tools for performing various agricultural tasks like •
cutting
•
plugging
•
seeding etc
2. This posses a solar panel for saving diesel & petrol cost. 3. Tractor has memory in which it will store information about tracks, fields, etc. 4. We can add Wireless camera & GPS module for video surveillance & positioning. (optional)
II.
BLOCK DIAGRAM
The block diagram of the project is mainly divided into two sections: •
User Unit (RF transmitter to control tractor.)
•
Tractor Unit (RF receiver on tractor and solar trapping system).
A. Solar powered Robotic Tractor: •
The tractor has various mechanical tools for performing different agricultural task like seeding, cutting, plugging etc.
•
The tractor is also equipped with various sensors to detect & avoid obstacle, fire etc.
•
The operation of tractor is control via wireless remote provided with user.
•
Tractor will use inbuilt memory to store track information, field information etc.
B. Wireless remote to control Robotic tractor
Fig.1 The transmitter used here is to control the tractor from a distant place. The data send from the switches is in parallel form and the transmitter module accepts the data in serial form. The Encoder will convert the parallel data to serial data and data will be given to transmitter. C. Robotic Tractor with solar trapping system The receiver module here will receive the wireless data send by the transmitter. The decoder will convert the serial data from module into parallel data. These parallel data is given to the motor driver to control the motor for navigation purpose and seed feeder.
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Fig.2 The circuit and the mootors will be powered p by the t lead acid battery whichh interns get charged by thhe solar paneel mounted onn the tractor.
RKING OF PROJECT P III. WOR 1. User U i.e. Farmeer has a remoote on which tthere are manny switches foor controlling robot. 2. The T robot /tracctor uses solaar panel for geenerating elecctricity & o/pp of solar panel is connecteed too a battery .soo in the day time the solaar panel will charge batteery & during night time thhe trractor takes poower from baattery. So it prrovides batterry backup alsoo. 3. Now N tractor is i having maany tools forr performing g various agrricultural taskk like cuttinng, seeeding, plugg ging etc 4. User U can contrrol all the taskk of robot via wireless RF tx t rx pair. 5. The T robot also o has obstaclee detection & avoiding faccility to avoidd any obstaclle if coming in thhe route of traactor. 6. In n this way freeely available solar power minimizes usse of diesel & petrol doingg automation in aggricultural system. A. How Solar S Cells Work W Photovolttaic Cells: Converting Phottons to Electrrons The solar cells that youu see on calcu ulators and saatellites are allso called phootovoltaic (PV V) cells, whicch me implies (pphoto means "light" and vvoltaic meanss electricity.)) converts sun n light directtly as the nam into electrricity A moduule is a groupp of cells connnected electrrically and paackaged into a frame (more commonlyy known as a solar panel), which can thhen be groupeed into larger solar arrays. Photovoltaic cells aree made of sp pecial materiaals called semiconductorss such as silicon, which is c Basically, B whhen light strikes the cell,, a certain portion of it is currently used most commonly. s r material. This T means thhat the energgy of the abssorbed light is absorbed within the semiconducto www.giapjjournals.com
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transferred to the semicconductor. Thhe energy knoocks electronss loose, allow wing them to flow f freely. PV P ht absorption to cells also all have onee or more electric field thaat acts to forcce electrons ffreed by ligh c directtion. This flow w of electronss is a current, and by placinng metal conttacts on the toop flow in a certain and bottom m of the PV cell, you cann draw that cuurrent off for external use,, say, to poweer a calculatoor. This curreent, together with the cell's voltage (w which is a resu ult of its buillt-in electric field f or fieldss), defines th he power (or wattage) w that the t solar cell can produce.
Fig 3 Working W of soolar panel an nd solar cell T B. Basic Theory H-bridge sometimes called as "fulll bridge" the H-bridge is so named beecause it has four switchinng motor elements at the "corners" of the H and the m he basic bridg ge is shown inn the forms the cross bar. Th t above .Th he key fact to note is that tthere figure to the are, in thheory, four sw witching elem ments withinn the bridge. These four eleements are often o called, high h h side righht, low side riight, and low side side left, high left (wheen traversinng in clockw wise order).The switches are a turned onn in pairs, eitther high left and lower righht, or lower Left L and high h right, but nnever both swittches on the same "side" of the bridge. If both switcches on one side of a bridg ge are turned oon it creates a short circuit between the battery plus and
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battery minus terminalls. This phenoomenon is callled shoot thrrough in the Switch-Mode S Power Supply (SMPS) liiterature. If thhe bridge is sufficiently poowerful it willl absorb that load and youur batteries wiill simply draain quickly. Usually U howeever the switchhes in questio on melt. To poower the motoor, you turn on two switchees that are a diagonallyy opposed. Inn the picture to the right, imagine that the highh side left annd s right sw witches are tu urned on. Thhe low side currennt flow is shoown in green. The current c flowss and the motor begins to turn in i a "positivve" direction, current flow ws the otther directionn through the motor and thhe motorr turns in the opposite direection. Actually it is juust that simpple, the trickyy part comes in when you decide what to usee for switchees. Anythhing that cann carry a currrent will worrk, from four SPST sw witches, one DPDT switcch, relays, traansistors, to en nhancement mode m power M MOSFET. On ne more topicc in the basic theory sectio on, quadrants. If each swiitch can be controlled c inddependently thhen you can do some interesting thinggs b some folks call succh a bridge a "four quadraant device". Iff you built it out of a singgle with the bridge, DPDT rellay, you can really only control c forwaard or reversee. You can buuild a small truth t table thhat tells you for f each of thhe switch's staates, what thee bridge will do. d As each switch has onee of two statees, and there are four switches, there are 16 possiible states. However, H sincce any state that t turns both o one side onn is "bad" (sm moke issues fforth), there arre in fact onlyy four useful states (the fouur switches on quadrants) where the trransistors are turned on.
h SideLower Hiigh SideHigh
Lower
Leeft
Righ ht
Left
Right
Quadrant Description D
Onn
Off
Off
On
Motor goes Clockwise
Offf
On
On
Off
Motor goes Counter-clockwise
Onn
On
Off
Off
kes" and decellerates Motor "brak
Offf
Off
On
On
Motor "brak kes" and
LICATIONS S IV. APPL The appliccations of theese robots are:
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1. Mars exploration robot was autonomous solar powered robot. 2. This principle can be used in day to day life in cars and automobiles. 3. Apart from the robot solar tracking and tracing can be used in industries, for home use.
V. ADVANTAGES 1. No fuel required as the robot is battery powered. 2. No external charging of battery is required as charging is done by the solar panel placed on the robot. 3. The tracking trapping of solar energy can be used for home appliances.
VI. FUTURE SCOPE In future we will try to improve this project & try to implement a trolley also. So this will fulfill complete kit for a former. Also we will try to make it more intelligent & autonomous.
VII. CONCLUSION This paper proposed an idea of automatic farming system lucrative advancement in the field of technology. The project we implemented, reduces man power and saves the conventional energy sources by performing various tasks of farming automatically & helps a farmer in his day to day work performing rapidly & effectively with the help of this system.
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REFERENCES 1.
RFID Handbook Fundamentals and Applications in Contactless Smart Cards and Identification by Klaus Finkenzeller, Wiley and Sons publications.
2.
RFID Field Guide: Deploying Radio Frequency Identification Systems By Bhuptani Manish.
3.
AIM, Inc. Shrouds of Time: The History of RFID. By Dr. Jeremy Landt
4.
Finkenzeller,Klaus. RFIDHandbook1. Second Edition. Chic ester, England: John Wile & Sons, Ltd. 2004.
5.
Sharma, Sanjay E., Stephen A. Weis, and Daniel W. Engeals. RFID Systems and Security and Privacy Implications
6.
Texas Instruments â&#x20AC;&#x201C; RFID support
7.
http://www.ti.com/tiris/default.htm
8.
RFID Forumhttp://www.rfidtalk.com/
9.
All datasheet - Datasheet search site for Electronic Components http://www.alldatasheet.com/
10.
AT89S51 MCUs overview http://www.atmel.com/dyn/general/tech_doc.asp?doc_id=7190
11.
Voice module: APR9600
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KUNAL ASTROCRYPTOGRAHY SECURITY USING DISTANCE FORMULA AND 3D GEOMETRY Kush Jain Department of IT, Army Institute of Technology, Pune, Maharashtra, India kushjain@gmail.com
Abstract In real world, data security plays an important role where confidentiality, authentication, integrity, non repudiation are given importance. The universal technique for providing confidentiality of transmitted data is cryptography. This paper provides a technique to encrypt the data using distance formula and 3D geometry. Keywords - Distance Formula, 3D Geometry, data security, authentication, cryptography, ASCII I. INTRODUCTION In the present world scenario it is difficult to transmit data from one place to another with security. This is because hackers are becoming more powerful nowadays. To ensure secured data transmission there are several techniques being followed. One among them is cryptography which is the practice and study of hiding information. [1] In the modern era of computers we can create more secure cipher text. In this paper we create cipher text using ASCII values of characters and 3D Geometry. II. LITERATURE SURVEY A. Cryptography Cryptography, to most people, is concerned with keeping communications private. Encryption is the transformation of data into some unreadable form. Its purpose is to ensure privacy by keeping the information hidden from anyone for whom it is not intended. Decryption is the reverse of encryption; it is the transformation of encrypted data back into the same plain text from which the cipher text was generated. [1] Encryption and decryption require the use of some secret information, usually referred to as a key. [1] The data to be encrypted is called as plain text.[1] The encrypted data obtained as a result of encryption process is called as cipher text.[1] B. 3D Geometry www.giapjournals.com
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A point in 3D plane can be represented using 3 coordinates (x, y and z). A point on a sphere of radius r and center (x0,y0,z0) can be represented as[3] x =x0 + r × cosθ × sinφ y =y0 + r × sinθ × sinφ z =z0 + r × cosφ Where 0 <= θ <= 2 π, and - π /2 <= φ <= π /2 C. Distance Formula Distance between two points A (x1, y1, z1) and B(x2, y2, z2) can be calculated as [2] Distance
d = ( x 2 − x1 ) 2 + ( y 2 − y1 ) 2 + ( z 2 − z1 ) 2 ⇒ d 2 = ( x 2 − x1 ) 2 + ( y 2 − y1 ) 2 + ( z 2 − z1 ) 2 III. PROPOSED METHODOLOGY In this method the first step is to assign a unique set of coordinates known only to receiver and sender. These coordinates are the origin of the Cartesian plane they are going to use for communication Another set of points known as stars should also be shared only between the sender and receiver. There should be at least 1 star. A constant m which signifies the maximum number of concentric spheres to consider is also decided. E.g. m = 10
Fig. 1 Multiple Stars
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Another set of spheres (specifying the radius and the center point (which should not enclose the sphere made by taking any stars center point and radius as the m × maximum range of ASCII)) known as black holes is also shared between the sender and receiver. There can be any number of such spheres (black holes) (The only restriction being that there is a possibility to encode all ASCII characters using stars)
Fig. 2 Blackholes The next step is to calculate the ASCII equivalent of each character in the message and add it with any multiple of the range of ASCII characters. Let’s call this value d Then we plot a point on the sphere with any star chosen at random from given stars and radius d. The point is plotted by taking any random value of θ and φ.
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We check if this point lies inside or on any black hole. If it does then we regenerate the point by going back to step involving generation of point.
Fig. 4 Points inside blackhole are ignored at the time of decryption We check that if this point already exists in the cipher text. If it does then we regenerate the point to get a different set of coordinates by regenerating the point by going back to step involving generation of point. If we keep getting the same result after trying many times, then only we repeat the point. We now check if this point is closest to the star from which it is generated in comparison to other stars. If not, then we regenerate the point by going back to step involving generation of point. Now we round the point to 2 decimal places and remove the decimal point and append it in cipher text by separating the coordinates with a comma. While generating points for each character, we also place any random number of points that lie in or on the black hole at the starting, in between or at the end of cipher text to generate a certain number of points that lie in or on the black hole To decode it, first retrieve the triplet from cipher text each of which is separated by comma. Then divide each number by 100. This will be the x, y and z values of the point. Check if this point lies on or inside a black hole, if it does then generate nothing. If it does not come in or on a black hole then find the star closes to this point and the distance of that star from this point. Round off this distance to nearest whole number. Take remainder by dividing this
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rounded distance with the maximum range of ASCII characters. This remainder is the ASCII equivalent of plain text character. Convert this ASCII value to character to get the plain text The entire coordinate system has origin which is shared just between the sender and receiver
Fig. 5 Station A,B,C have same stars and blackhole but it is difficult for them to see messages meant for other station as they have different origin IV. ADVANTAGES 1. Since it uses ASCII, it can encrypt any character including A-Z, a-z, 0-9, spaces as well as special characters supported by ASCII[4][7] 2. Since it generates random points on a sphere of random radius for a particular character. There can be 360Ă&#x2014;180Ă&#x2014;m points for a particular character by trying not to repeat the same point again for the same character. 3. It generates random useless points in between, thus fixed size messages can be generated providing more security compared to other cryptographic algorithms[5][6][1] as the number of characters in original message cannot be found from encrypted message without the knowing the black holes
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4. There can be many stars, thus even if only 1 star is leaked, the message can only be partially decrypted 5. The receiver also needs to know the origin; if he does not know it then it is difficult to read the message 6. Message cannot be decrypted completely till all the stars and origin are known 7. Even if the algorithm is known, it is almost impossible to extract the original text without knowing the stars and origin 8. Even with the same set of stars, blackholes and origin , we get many different points for the same character, thus making it more secure. V. CONCLUSION The above cryptography can be applied mainly in military where data security is given more importance. Instead of ASCII Unicode can also be used, which would provide the ability to encode and decode messages in one’s native language and thus increasing security. Thus usage of stars, black holes and origin ensures that the data is read only by authorized personnel REFERENCES 1. S. Pavithra Deepa, S. Kannimuthu, V. Keerthika ,“Security Using Colors and Armstrong Numbers”, Proceedings of the National Conference on Innovations in Emerging Technology2011 Kongu Engineering College, Perundurai, Erode, Tamilnadu, India.17 & 18 February, 2011.pp.157-160 2. An article on Distance http://en.wikipedia.org/wiki/Distance 3. An Article on Sphere http://en.wikipedia.org/wiki/Sphere 4. An article on ASCII codes http://en.wikipedia.org/wiki/ASCII 5. Dr.M.Mohamed Sathik, A. Kalai Selvi, ” Secret sharing scheme for data encryption based on polynomial coefficient”, 2010 Second International conference on Computing, Communication and Networking Technologies 6. Mohammad Zakir Hossain Sarker, Md. Shafiul Parvez , “A Cost Effective Symmetric Key Cryptographic Algorithm for Small Amount of data” 7.
Ahmed Desoky, “Cryptography: Algorithms and Standards”, 2005 IEEE International Symposium on Signal Processing and Information Technolog
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PROPOSED CRYPTOGRAPHIC ALGORITHM FOR IMPROVING DATA SECURITY Dipankar Som Kalyani Government Engineering College, Kolkata, India somdipankar@gmail.com
Abstract Cryptography is a Greek word which means secret writing. However we use this term to refer to the science and arts of transforming the message to make them secure and immune to attacks. Access to stored information has increased greatly. More companies and institution store official and individual information on computer than ever before. So information security is a matter of deep concern. In this paper I have proposed an algorithm which is based on block cipher concept. In this algorithm I have used simple mathematical operations like XOR and shifting operations. Speed and complexity are two important aspects of block ciphers. The block length of the block cipher decides the complexity. The key complexity also imposes a constraint on the length of the block cipher. In my proposed work the keys are generated by a random key generator and a new approach for S-box is used., Key words: Internet security, Encryption, Decryption, Cryptography I.
INTRODUCTION
Plain text & Cipher text: The original message before being transformed is called plain text. After the message is transformed on the application of algorithm is called cipher text. Cipher We refer to encryption and decryption algorithm as ciphers. The term â&#x20AC;&#x2DC;cipherâ&#x20AC;&#x2122; is also used to refer to different categories of algorithm in cryptography. Key A key is a number (or as set of numbers) that the cipher as a number operates on. II.
CATEGORIES
We divide the entire cryptographic algorithm (ciphers) broadly into two groups:1. Symmetric- Key cryptographic algorithm. 2. Asymmetric-Key cryptographic algorithm.
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Figure 1: A conventional model of Cryptography Symmetric-Key Cryptography In the symmetric key cryptography the same key is used by both parties. The sender uses this key as an algorithm to encrypt data; the receiver uses the same key and corresponding decryption algorithm to decrypt data. Asymmetric-Key Cryptography In the asymmetric key cryptography there are two keys: a private key and a public key. The private key is kept by the receiver. The pubic key is announced to the public. Let us discuss something about the traditional ciphers which are though obsolete but helped in the evolution of the modern ciphers. III.
TRADITIONAL CIPHERS
We divide traditional ciphers into two broad categories:1. Substitution ciphers. 2. Transposition ciphers. Substitution Cipher A substitution cipher substitutes one symbol with another. If the symbols in the plain text are alphabetic character we replace one character with another. Transposition ciphers In transposition ciphers there is no substitution instead their location alters. A character in the first position may appear in the different position in the cipher text. IV.
MODERN ROUND CIPHERS
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These ciphers are bit oriented. XOR cipher It uses the exclusive-or operation between two data inputs; plaintext as the first and the key as the second. Rotation cipher This cipher rotates the input bit left to right. It may be keyed or keyless. S-box An S-box (substitution box) parallels the traditional substitution cipher for characters. The S-box is normally keyless and is used as an intermediate stage of encryption and decryption. P-box A P-box (transposition box) for bits parallels traditional transposition cipher for characters. It performs a transposition at bit level; it transposes bit. V.
PROPOSED ALGORITHM (EXPERIMENTAL DESCRIPTION)
The proposed work is mostly based on a class of Feistal Ciphers technique in which the encryption and decryption process are very similar even identical in some cases requiring only a key reversal. Thus the size of the code and circuitry required to implement such a cipher is almost halved. The basic steps involved in my proposed work are:1. Bit-Shuffling 2. Substitution boxes or S-boxes. 3. XOR operations to create a large amount of data. Successful block cipher design integrates the concept of Confusion and Diffusion. Essentially looking at the output no idea can be made about the input, in other words input should not bear a statistical regularity with the output. Confusion is the measure of the statistical relationship of the input on the output. Diffusion, on the other hand is the tendency to extend the influence of the input symbols on the output words to alienate the tendency of the input symbols on the plain text.
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Start
Plain Text
256 –bit Plain text
Split (64*4)
64 bit
XOR
DES
64 bit
64 bit
XOR
XOR
DES
DES
64 bit
XOR
Random Key Generator
DES
Merge (256 bit)
Substitution Box or S-box
Cipher‐text
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Steps of Proposed Algorithm 1. Firstly a 256 bit text is obtained as the plain text. 2. Next the 256 bit text is divided into four arrays (64*4) using permutation or bit-shuffling. 3.
The keys are generated as different lengths (64,256) from a random key generator and are not entered manually.
4. Now the plain text is XOR-ed with the key generated. 5. Next the 64 bit text is passed through the DES block with the keys generated from the key generator. 6. Now the four arrays of 64 bit text is merged into the 256 bit text and subsequently passed through the S-boxes to obtain the cipher text. 7. In the substitution step (S-boxes) the substitution occurs in presence of the random key generated from the key generator.
VI.
RESULTS & CONCLUSION In this proposed algorithm it has been found that the speed and complexity of this block cipher is better than the DES algorithm, while due to its Freisel mode of operation the code and circuitry of this are very similar to each other. The S-box function of DES is an 8-tick time consuming function because there are 8 s-boxes perform serially. In the proposed algorithm, the s-box is take a 1-tick time consuming function because there is 1 S-box perform in parallel-wise each of rows to calculate the output. The complexity of any block cipher depends on the block length or key length unless special break through is done. The DES deals with 64 bit and so the complexity is 264 while the complexity of the proposed algorithm is 2256.
REFERENCES [1] Norman D. Jorstad “Cryptographic Algorithm Metrics”, January, 1997, pp. 1-10 [2] Prof. Dr. Hilal Hadi Salih & Dr. Ahmed Tariq Sadiq, “Proposal of new block Cipher Algorithm”, pp. 10-18. [3]Bhaskaran Raman, “Cryptography & Network Security”, IIT Kanpur, May 2005 [4] “Feistel Cipher”, Wikipedia, the free encyclopaedia Retrieved from http://www. Wikipedia .org.
[5] Vishwa gupta, “International Journal of Advanced Research in Computer Science and Software Engineering”, Vol. 2, Issue 1, January 2012, pp. 1-3. [6] Behrouz A. Forouzan, “Data Communication and Networking”, Fourth Edition, pp.968-1030
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WEBO-KIT: AN ENHANCED WEB UI TOOLKIT Sukeshni Kantrod, Kanchan Jondhale, Purva Kshatriya, Namita Maharanwar UG, Department Of Computer Science, Pune Institute of Computer Technology, Pune, India. sukeshni.kantrod@gmail.com, kanchanjondhale@gmail.com, kshatriya.purva@gmail.com, namitamaharanwar@gmail.com
Abstract Designing UI and backend are one of the main aspects of Web application development. Developers waste a lot time in designing tool like tree view, grid view etc. one by one whenever required as per the requirements of application. Solution to these problems are building UI toolkit library containing commonly required tools, include that library and drag-drop the tool while building application. The existing UI toolkits have less number of tools and do not contain each and every tool, have a lot of ambiguities in their behaviour pattern, look-feel, large in size and have cross browsing problem. There is a need of powerful UI toolkit which will have all necessary tools, consistent behaviour pattern and light in weight. If we compare same tool from different libraries, they may have different properties which can be combined under one library as a feature rich library. Our objective is to combine all the properties of a tool from different available web UI toolkits like kendo, dojo, jQuery UI, YUI etc., providing consistent behaviour pattern, look-feel, cross browser support, add new features and light in weight. On the basis of analysis done on various available toolkits, feature rich and configurable library of commonly used tools is being created. Key words: Cross browsing I.
INTRODUCTION
A good UI is a must for correct interpretation of information by user therefore it should be well mannered. Developers waste a lot time in designing a particular tool whenever required as per the requirements of application. This was very time consuming procedure. Then developers find a library containing collection of all necessary tools. Developer has to just include that library in their application and drag-Drop the tool while building application. But there is no such toolkit which has all necessary controls in it. Developers first decide which tool they will require in their application. As per the requirement of a particular tool, developers analyze different toolkits to get the best tool amongst them in terms of behavior, look, functionality, etc. but they didnâ&#x20AC;&#x2122;t get such toolkit satisfying their needs. Therefore, they have to refer at least 2-3 toolkits for building application, resulting in the increase of size of
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application. Also, this result in lot of ambiguities in their behaviour pattern, look-feel, as the skin of a tool from different toolkit is different. II.
ANALYSIS OF EXISTING TOOLKIT
Every toolkit has its own advantages and disadvantages. The main motto is to create a new library having combination of advantages of all toolkits into one and build that library on top of existing jQuery based libraries. For this purpose it is necessary to analyse all the possible toolkits considering the parameters like size, look-feel i.e. cross browser support. Amongst them, some are based on jQuery and some are non jQuery based. As the jQuery itself is very light in weight, therefore more stress is given on jQuery based libraries. The list of analysed toolkits is as follows: 1. Kendo UI Toolkit from Telerik 2. Infragistics 3. YUI 4. jQuery UI 5. DOJO
Figure 1: kendo Drop down control Figure 1 shows kendoâ&#x20AC;&#x2122;s dropdown control where the orange colour is not suitable at enterprise level. III.
COMPARATIVE STUDY
Table 1: Comparative study of toolkits
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According to chart in Table 1, jQuery UI is smallest in size, kendo has better looking in UI, Infragistics and YUI are very large in size and have average looking UI. Jquery UI lacks largely required controls like grid view, tree view etc. it consists of basic controls like button, checkbox etc. All the toolkits provide cross-browser support. By observing the data mentioned it is clear that kendo toolkit has average size and better looking UI as compared to other toolkits. IV.
WEBO-KIT: THE PROPOSED TOOLKIT
The proposed toolkit has following characteristics •
Small in size.
•
Cross browser support
•
Better UI
•
Collection of majorly used tools
•
Reduced skinning problem
The enhanced library will contain commonly used tools like Grid control, tree view, tab view, modal dialog, buttons, textbox, combo box, radio button, generic web control, check button calendar control, collapsible panel, menu bar progress bar and many more so that the developer will require refer only one library for the application to be developed. Web controls
Enhanced properties
Client side control
Standardized web UI toolkit
Figure 3: WEBO-KIT V.
DESIGN & IMPLEMENTATION
An analysis of a toolkit is done from various available toolkits and the one with the best amongst is chosen as the base for further enhancement of UI properties and features. Some new features that can be added are ascending and descending order, sorting on the basis of character at the start and end of a data word. Inputs from web developers for proper colour to be chosen for better data interpretation at enterprise level is been taken. On the basis of result obtained after analysis, a proper colour, feature, properties are added to the basic tool available. ASP.net framework is used for the development of a particular tool. The technologies used are jQuery, HTML5, CSS3, ajax and JSON for developing a tool. The data required by the tool is provided using web service which can provide hard-coded data or can retrieve data from some data storage like MySql database for demo purpose. The web service is located at any server so www.giapjournals.com
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that any client can have access to it. This makes the data in a tool and UI of a tool separated from each other. The UI controller i.e. the view of the tool, the data provided are separate from each other. Hence the tools support MVC (modal view controller) form which keeps the implementation and the data source separate from each other. Reference of web service is provided to the asp.net project as a data provider.
Figure 4: Data Grid View For example GridView as shown in the Figure 4 the filtering feature can be obtained just by a click on the key shown in column head, blue colour is chosen for interpretation of data selected, a click on the view details button will give all the details of the selected record in pop up form. The notable thing about Webo-kit is the data shown in tools is retrieved through web service dynamically from database. VI.
PERFORMANCE
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The comparison chart shows the decrease in size of toolkit in regard with decrease in size of grid-view and tree-view, tab-view, drop-down of toolkit designed as compared to infragistics’s toolkit. As the size is small the loading time required for application in which this toolkit is used will be small.
VII. FORMAL MODEL S = {I, O, F, Sc, Fc} Input (I): {Default.aspx} Output (O): {library} Functions (F): {UIdesign (), getData (), addProperties (), createLibrary ()} UIdesign (): Design UI of a particular tool. getData (): Get data from webservice. addProperties (): Add features/properties to the tool i.e. enhancement of tool. For example in case of grid-view sorting, filtering etc. features are added. In case of drop-down, checkboxes are added. createLibrary(): To create a library of tools developed. Success cases: Su= {Sc1^Sc2} Sc1 → supports latest browsers (IE 7+, Chrome, and Firefox) Sc2 → get correct data from web service Failure cases: Fc = {Fc1, Fc2, Fc3} Fc1 → does not support older browsers Fc2 → no data displayed, if data from web service is incorrect. Fc3 → no output, if Default.aspx is not compiled correctly. VIII.
CONCLUSION
The proposed modified web UI Toolkit is easy to distribute compared to other toolkits that require installation to function. Web UI toolkit is also useful for creating the templates which will be useful for programmer to develop the application only by dragging these templates. IX.
FUTURE SCOPE
The future research is to provide user-specific customized properties window where user will have a set of skins to be applied to the control. The user will be able to change the skin of control as per his choice.
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X.
ACKNOWLEDGMENTS
We would like to take this opportunity to thank Professor Atish Londhe (the department of computer science) at Pune Institute of Computer Technology, Pune for constant encouragement and assistance he provided us at every stage of the project. We would also like to thank Dr. G. P. Potdar, Head of Computer Engineering, Pune Institute of Computer Technology, Pune for his encouragement and support. REFERENCES [1] Ganji, R.R.Mitrea, M.; Joveski, B.; Preteux, F. HTML5 as an application virtualization tool
Consumer Electronics (ISCE), IEEE 16th International Symposium on 4-6 June 2012 [2] Yang Jianping, Ahang Jie Towards HTML 5 and interactive 3D graphics, Educational and Information Technology (ICEIT), 2010 International Conference on September 2010 [3] Mesbah, A. Mirshokraie, S. Automated analysis of CSS rules to support style maintenance. Software Engineering (ICSE), 34th International Conference on 2-9 June 2012 [4] MDN website: https://developer.mozilla.org/en-US/ [5] Kendo website: http://kendoui.com
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EFFICIENT MULTI HOP ROUTING ALGORITHM FOR BLUETOOTH DEVICES Ganesh Gupta1, Shubham Gupta2, Manish Kumar Singh3, Durbadal Chattaraj4 1,2,3,4
Department of Computer Science & Engineering,
Narula Institute of Technology, Agarpara, Kolkata, West Bengal, India 1
gupta.ganeshnit@gmail.com, 2shubhamnit@gmail.com, 3manishkumarsinghnit@gmail.com, 4
durbadal.chattaraj@gmail.com
Abstract On wireless ad hoc network (AHN), ad-hoc mode is a method for wireless devices to directly communicate with each other. Since AHNs are dynamic in nature, they require a dynamic routing protocol to send the message from one source node to destination. Several approaches have been proposed for designing multihop routing protocols in wireless AHNs. Flooding is one of them to discover a dynamic routing path. But Flooding of request packet in the route in wireless AHN creates a huge amount of traffic which leads to high probability of packet collisions. Also it causes significant over head in delivering of packet and hence is inappropriate for the dynamic routing. It also causes more time consumption. In this paper we propose a efficient multi hop routing algorithm to deliver the message using the cache variable for intermediate to reduce a large number of path& hence reducing the traffic generated by normal flooding. We also apply a logic to share the dynamic routing table between different devices in neighborhood. We also propose a scheme at receiver side to receive only one valid message from the flooded message and discard all other flooded messages. I.
INTRODUCTION
Wireless Ad-hoc Networks (AHNs) is a set of wireless independent multihop nodes which does not require any preexisting infrastructure. This network directly connects one wireless device to another without using any router or hubs. Instead, each node take part actively in routing by forwarding packet to other nodes, and so the determination forwarded packet is made dynamically based on the network connectivity. So, There is no concept of a particular server, any node can be a server or client. It allows all wireless devices to discover and communicate in peer-to-peer fashion with other who are present within the range or outside the range (communication is done in multi hop fashion) without involving any central access points (wireless routers or hubs). Some of the nodes in ad-hoc network may not be able to communicate directly with each other and dependent on some other nodes to pass their message. Such networks are often known as multi-hop or store and forward networks. The intermediate node act as routers, which discover and maintain a table to forward the message to other nodes in the networks. Ad hoc networks have played an important role in following www.giapjournals.com
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1) Military Environment: In case of battlefield adhoc network can be formed by tanks and planes to communicate with each other. 2) Emergency Operations: In case of rescue working operating in disaster area can form adhoc network to communicate with each other. 3) Personal Area Networking: Adhoc network can formed by Cell phone, laptop, wrist watch to form a PAN 4) Education: Used in Virtual classrooms, conferences
Fundamental Protocol in Ad-hoc Networks Since Wireless Ad-hoc Networks are a new scheme in the field of networking and it is different from the wired networks. Thus the main issue in AHN is self-organization and wireless transport of information [4], [5].Since the nodes in a Wireless Ad-hoc Network are mobiles in nature so they are free to move arbitrarily at any time at any position which results in dynamic and unpredictable topology. This makes routing process difficult because the topology can be changed any time. Traditional routing algorithm like link state routing ad distance vector routing is not suitable for adhoc networking due to the reasons mentioned before. So, proper design of the ad-hoc routing protocol is needed to overcome the problem. Several protocols have been proposed for routing in ad hoc networks [3â&#x20AC;&#x201C;15, 18-22, 25]. These routing protocols can be classified as basically of following types1) Proactive algorithm 2) Reactive algorithm 3) Hybrid algorithm 1) Proactive Algorithm Proactive algorithm maintains routing tables that contains the
lists of destinations and their
corresponding routes .The tables are updated periodically by sharing of tables with the adjacent node. The disadvantage of this algorithm is that, it requires large amount of data for maintenance and it has slow response to node failures and change topology. www.giapjournals.com
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2) Reactive Algorithm This type of protocol is also known as on- Demand routing. Here the term on â&#x20AC;&#x153;on demandâ&#x20AC;? means that the sender node will try to find the route of destination only if it has to send some data. The node will maintain the route as long as it is needed by it. Therefore, these protocols require less control overheads. The routing is based on the shortest path algorithm to determine the host. 3) Hybrid (both pro-active and reactive) routing Hybrid protocol is combination of both reactive protocol and proactive protocol. Here each node first maintains the routing tables as in case of proactive protocol. The node will also participate in handling the demand of routing that comes from nodes through reactive protocol. II. RELATED WORK Flooding is a method of broadcasting the packets. Here a node first broadcast packet to all its neighbor nodes .The receiver node will again forward each incoming packet to its neighbor except the one from which the packet come from, until packet reaches the destination. Several authors have proposed to use the basic ideas of flooding. A reliable broadcast protocol was proposed by Pagani [19] for networks that have unpredictable dynamic topology. It gives a routing algorithm that ranges between flooding and the traditional routing protocols. A Controlled Flooding protocol was proposed by Lesser and Rom [16]. In this, a message is limited broadcast on the basis of flooding mechanism ie not throughout the network. Traffic is further limited by assigning a cost to each link and a wealth to each message. A message is sent on a link on the basis of priority ie low wealth packet will be sent upon receiving a message; an intermediate node subtracts the cost of the link from the message wealth. We propose a multipath routing protocol known as Efficient Multi hop Routing. The protocol is proactive .It uses the basic features of flooding, but restricts packet propagation by using a cache variable which store packet id. It restricts the transmission of duplicate packet having same id that it has received early. Here the intermediate node will also not transmit packet to those node from which it comes from starting from the sender. Hence flooding becomes optimized as it uses adaptive mechanisms for restricting flooding in the network. III.
THE EFFICIENT ROUTING PROTOCOL: OVERVIEW & OUR SCHEME
The traditional algorithm is suitable where rate of topological changes is low but it fails when high. So when nodes changes its position, the best way is to flood packets in the network [13].so that at least one packet can be reached. We proposed an algorithm which is based on optimized flooding .In this scheme we try to deliver packet to the sender at the most appropriate path .We assume each node to be host and receiver and www.giapjournals.com
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each maintains a routing table to route the packet The Bluetooth address is used to uniquely identify each node in the networks .In the routing table for every entry of node, there is list of nodes from which a particular node can reach the sender who wishes to send message first check whether the destination exits in its coverage area or not if exist then it will send the packet directly to it ,otherwise it finds the list of adjacent nodes from which the destination can be reached and broadcast the message to all of them. Here the contains are id, destination name and the routing path .At the intermediate node , it first check whether its cache contains the packet id or not if contains then it simply discard otherwise it will first find all the list of nodes to which destination can be reached and broadcast all of them except the nodes which are already in the routing path of packet ,secondly it will store the packet id to its cache so that any In future if it receives any packet with the same id it will discard it. This process continues until the message is delivered to its destination. The receiver received the packet and sends the acknowledged directly to the path from which the packet is received. We assume that each nodes have a routing table which can be updated dynamically, initially when a node starts it first search for neighbor and add them to its routing table .After that it will broadcast its table to its neighbor. On receiving the broadcast message it neighbor will updates their table as given by the flowing example Diagram of table 1 Now suppose that two new nodes D,E are introduced into the network on which node D is in the range of pre-existing network, and E is out of range .Now both device start searching the device and D found C and E found only they make entry in their table. Diagram 2 Now both start sharing the table. After that the table will be shown in the following diagram Diagram 3 Now after a fixed time interval each node will again search for devices and search their table to their neighbor this will lead to dynamic entry in each routing table of nodes. Packet format Each node in the ad hoc network communicates with each other by exchange of the message. The message consist of two parts the header portion and the body portion The format of message is shown below Header
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Body
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Message-
Type
Destination
path
Hop
id
Count
Message-id = this id is generated at the sender side to identify each packet uniquely. Destination = Bluetooth address of the destination node Path= this contains the routing path through which packet is coming the last node in the path will be the sender Hop Count =Contains the maximum number of hop the packet can travel it si used to avoid Type: This define the type of message sent Type 1: indicates the message contains sharing routing table Type 2: indicate the normal message Example Header
1559
Body
1
D
A,S,E
10
We have path A-S-E, this means that message comes from E, the sender via S-A to receiver D With type 1 i.e. it contains the share routing table of E also it has unique id 1559 Following format Node
Address
XX
Add_1
YY
Add _2,Add_1,Add_3
ZZ
Add _3,Add_2
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Now suppose the sender S wants to send message to D it finds that it can go from D via A and B having A has highest priority. IV.
ALGORITHM
Routing in the Bluetooth Ad-hoc network is based on limited flooding. In this type of routing the sender first checks the entries in the routing table the message to all the adjacent node from which it has to send the message .The intermediate node will accept the message IF it is the destination of the message otherwise it will flood the message to all the adjacent node from which destination can be reached except to those nodes from which the message has been reached to it. The intermediate node also note down the messageID in its cache so that IF in future any message comes with that particular id could be neglected Sender Side Suppose sender S wants to send the message to D Step 1: find the list of addresses based on hop count which D can be reached in the routing table Step 2: three cases arises Case1: Single entry i.e. it can be reached only directly, in this case the following event occurs a) Send the message to D b) SET COUNTER =3 c) DO WHILE COUNTER !=0 d) wait for acknowledge received till timeout e) IF acknowledge received, ELSE {
Terminate process
resend (message,D) COUNTER--;
ENDIF
}
ENDLOOP
f) Remove D from the routing table as it is not reachable and print message destination not reachable Case 2) Entries are all indirect then Step2) sendAll (urlList) Step 3) Wait for the acknowledgement
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Step 4 IF receive acknowledge then Terminates the process ELSE Remove the entry in the table for D Case 4)Entries contain both direct and indirect path then it Step 1: first try to send directly i.e. send(message,D) and wait for acknowledge Step 2: IF acknowledge received within Timeout then Terminate the process ELSE Flood the message to all possible multi hop path i.e.send All(message)& wait for acknowledgment IF any acknowledge received within time out then Terminate process
ELSE
Print msgdestination Unreachable &
Remove that Entry from the table
END IF
ENDIF
Receiver side: suppose node S want to send the Message to D vi A-B. When the packet is received at the node can be of three types. Case 1: node is the destination Step 1:the node will simply Accept the message. And extract the body message & use it. Step2: Send the acknowledge to source through the path
in the header portion through which the
message has come. Receiving Process IF header type is equal to `1 then discard message
IF localcacheconatins message ID then return ok
ELSE
process(message, sender)
add the message id to cache
return ok
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ELSE
IF destination equals the receiver then
local cache contains message ID then return ok print â&#x20AC;&#x153;message received â&#x20AC;? return ok ELSE
IF
discard message ELSE add the message id to cache ENDIF redirect(message, header)
ENDIF ENDIF Process (message, header) Node
List
B
B,C
C
C
D
D
Suppose a node A maintains its table as follows
Now entry for B means that it can be reach from C or directly Now suppose routing table comes from C in the following form Node
List
A
A
D
C
E
E
F
F
B
B,E,F
At the receiver side it first check whether an entry exist for the coming sender or not if not found i.e. the case when the sender node starts after completion of search of node of receiving node then it first search for the device and make entry in the table and process as follows
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1) Search for each entry in the incoming table with the existing table except entry for node which receives the table. 2) IF matches found then i) Check the corresponding list entry in the existing table against each entry in list of sender node in the existing table. ii) IF no entry found then
a) add the entry to the list
iii) Else
add entry for the node, list in the table
3) End For example for Node D entry in the table is D
D
The incoming entry for D is D
C
As the previous list entry for D does not contains entry for C there for list is added so it becomes D
D,C
Similarly entry for E, F is not present in the A table so they will be added But in case of B there is already entry of C in the existing table B
B,C
C
C
D
D,C
E
C
F
C
It may also possible that there can be more that there would be more than one more than on entry for the sender in the existing table Redirect (message, header)
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Step 1: add the local address (i.e. node which is redirecting) to the beginning of the path field in the header Step2: find the list for the destination of the packet to be redirected Step 3: send the packet to all the nodes form where the destination to be reached Step 4: wait for acknowledgement Step 5: if ack not received within time then return OK to the sender; Else return failed to sender Step 6: END V.
PROTOCOL APPLICABILITY AND ASSUMPTIONS
The main assumptions underlying the proposed protocols are 1) Each node first discover the nodes in the neighbor zone during startup 2) Each nodes periodically shares its routing table with each other 3) If a node discover that on for its neighbor is no longer in its zone then it will updated its table and also informed its neighbor nodes. 4) We assume that the intermediate node has sufficient memory to relay the incoming message To be transmitted VI.
CONCLUSION
Our algorithm solved the problem of multihop adhoc network which optimized the routing and reduces a large number of path generated by flooding. Also each node will first prefer to send directly to node instead of broadcast the packet to all its neighbour .this will greatly reduce the overall traffic generated by flooding of packet.
REFERENCES [1] Y. Azar, J. Naor, R. Rom. Routing Strategies in Fast Networks IEEE Transactions On Computers, 45(2):165-173, 1996. [16] O. Lesser, R. Rom. Routing by controlled flooding in communication networks in proceeding of IEEE INFOCOM’90,(San Francisco, CA), pp. 910–917, June 1990. [19] E. Pagani and G.P. Rossi. Reliable broadcast in mobile multi-hop packet networks. Proceedings of the third annual ACM/IEEE International Conference on mobile computing and networking (MOBICOM’97), pp. 34–42, 1997. [4] M. Satyanarayanan. Fundamental challenges in mobile computing. Submitted paper. [5] M. Haardt W. Mohr R. Becher, M. Dillinger. Broadband wireless access and futurecommunication networks. Proceedings of the IEEE, 89(1), 2001. [3] S. Basagni, I. Chlamtac, V.R. Syrotiuk and B.A. Woodward. A Distance Routing www.giapjournals.com
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Effect Algorithm for Mobility (DREAM), Proceedings of the fourth Annual mobile computing and networking, October 1998. [15] P. Krishna, M. Chatterjee, N.H. Vaidya and D.K. Pradhan. A Cluster-based Approach for Routing in Ad hoc Networks. In proceedings of Second USENIX Symposium on mobile and Location Independent Computing, pp. 1–10, January 1996. [18] S. Murthy and J.J. Garcia–Luna–Aceves. An Efficient Routing Protocol for Wire-Less Networks. ACM Mobile Networks and Applications, Special Issue on Routing in Mobile Communication Networks, 1(1):183–197, October 1996. [22] C.E. Perkins. Ad hoc on-demand distance vector routing, Internet Draft, Internet Engineering Task Force, work in progress, December 1997. [25] C.-H. Toh. A novel distributed routing protocol to support ad-hoc mobile computing, Proceeding of 15th IEEE Annual International Phoenix Conference on Computer Communications, pp. 480–486, 1996.
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WORKING MODEL OF WATER JET CUTTING SYSTEM ON LOW PRESSURE J. N. Mehta1, R. Wadgaokar2, A. Khatal3, M. Chavan4 Mechanical Department, MCTâ&#x20AC;&#x2122;s Rajiv Gandhi Institute of Technology, Mumbai, India 1 jimit_mehta143@yahoo.com
Abstract Cutting of raw materials is one of the most common functions in industries. With the advent of globalization and tough competition from multinational companies, it becomes very essential for production houses to reduce/eliminate wastes due to inefficient cutting methods.
Every cutting
method is based on the input of energy into the material, in order to overcome the chemical bindings present in the structure of the material. Thermal cutting methods, for example, utilize the energy of chemical reactions, electricity, or light to produce high temperatures in order to melt the material at the cutting kerfs. Mechanical methods utilize the kinetic energy of the moving tool or form ductile materials through the application of pressure. However, these methods causes distortion of material in the heat affected zone. In Water-jet Cutting, the energy of the rapidly moving jet is utilized either in the form of a pure water-jet or abrasive water-jet and then applied to the work piece causing micro-erosion. The cutting water works as a cooling agent of cutting edge, thus allowing for a very high quality cut without producing heat affected zone. Keywords: cutting, micro-erosion, heat-affected zone. I.
INTRODUCTION TO THE PRJECT This paper is the outcome of the project accomplished in partial fulfillment of final year engineering project-making. The aim of the paper is to demonstrate the concept of water-jet cutting systems and empower the research activities and cost-reduction methods to promote the use of the same in India. A water jet cutter, also known as a water jet, is a tool capable of slicing into metal or other materials (such as granite) using a jet of water at high velocity and pressure. Its most significant attribute as an accurate cold cutting process allows it to cut metals without leaving a heat affected zone.
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The system uses a jet of pure water at high velocity and pressure. or a mixture of water and an abrasive substance. The process is essentially the same as water erosion found in nature but greatly accelerated and concentrated. There are basically two types of water-jet cutters: a) Pure Water-Jet Cutter b) Abrasive Water-Jet Cutter As a part of our project, we have successfully developed a working model of pure water-jet cutting system. The system utilizes a pump of capacity 2000 psi and 140 bar pressure as compared to 60,000 psi and 4000 bar pressure in present industrial use. Such pressure pumps are usually used in garages for car washing. In actual cutting systems, the pressure is intensified by double acting intensifier, whereas we have obtained the intensification with the help of piston movements as shown in fig(2).
Fig.1. Actual Intensifier
Fig.2.Intensification by Piston Action
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Fig.3. Water storage tank (2000 litres)
Fig.4.Water Purifier
Fig.5.Sand Feeder
II.
INDUSTRIAL STUDY An observatory study was made at one of the Waterjet Cutting Services Factory on the following Machine: WATERJET GERMANY M/C Abrasive Waterjet MODEL NO:S3015 BED SIZE: 3000mm x 1500 mm Pressure Range: 3600-4000bar Sand FeedRate :400-800 gm/min Material not cut-Toughened Glass The following figure shows the different components of the Water-jet Cutting System.
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Fig 6 PLC System
Fig.7.Waterhead Cutting a material
III.
DESIGNS/DRAWINGS:
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Water Jet Cutting Systems utilize the ‘intensification principle.’ In industrial units, water is pressurized to a pressure of approximately 200 bar. A plunger with a face area of 20 times less than the passage pushes against the water. Therefore, the 200 barpressure is ‘intensified’ twenty times, yielding The ‘intensification principle’ increases the pressure according to the following Pascal’s Law equation. y
PRESSURE = FORCE /AREA
We have selected SS-316 as raw material for nozzle and nut, for its strength and resistance to water corrosion. The software used is Pro-E wildfire 4.0 . To obtain considerable velocity of water-jet at outlet, we obtained an orifice of 1 mm diameter. Water would flow through it after passing through the nozzle of 3mm diameter. The outer diameter is 21 mm to provide considerable wall thickness to sustain such high pressures. The designs and stress-stain analysis are shown in the given figures.
Fig.8.Nozzle Design
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Fig.9.Nut Design
Fig 10 Office Design
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Fig.11. Assembly of cutting head
Fig.12.Stress-Strain Analysis for nozzle
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Difficulties that were involved 1.
The initial problem was to get a through-hole drilled in 150 mm long SS rod, which is not possible with conventional drilling methods.
2. The other problem was to obtain a considerable pressure to cut through thin materials like foam, rubber, etc. How the Difficulties were overcome 1. Drilling was done with the help of EDM at a die-making factory. 2. Garage pumps were found to give required pressure and discharge through a small orifice.
IV.
PROJECT DEMO
The following figures are snapshots of demo carried out in college. Further, the observation table has been prepared which gives an indication of cutting speed to be used for different materials.
Fig.13.Actual Cutting Head
Fig.15.High Velocity Water jet
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Fig.14.Orifice of 1mm diameter
Fig.16.Cutting through a brick
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Fig.17.Cutting P.O.P. Block V.
Fig.18.Cutting Foam
PROJECT OBSERVATIONS:
Pump Specifications: 140 bar 2000psi Orifice size: zero degree, 1mm Lpm:11 Power requirement:Single phase, 4 HP Table 1 Sr. No
MATERIAL
THICKNESS (mm)
CUTTING SPEED (mm/min)
1
P.O.P.
2
59.1
2
TYRE
2
3008.78
FOAM
12
5179.89
3
Table 2 SR.NO
MATERIAL
1
RUBBER
2
SYNTHETIC MATERIAL
3
FOAMED MATERIAL
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THICKNESS (mm) 2 10 20 2 5 10 10 100
CUTTING SPEED (mm/min) 27000 11500 2200 22500 8900 3400 27500 5500
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Table1 and Table 2 gives the obsevations of our project as well as industrial standards, We observe that the readings are almost consistent with these standards, taking into consideration the pressure difference. VI.
FUTURE PLANS We plan to automate our project using steeper motors to give it controlled motion, restricted to a plane in x-y direction.
VII.
APPLICATIONS OF WATERJET CUTTING •
Pure waterjet is used mainly for relatively soft materials such as plastic, textiles, paper, sealing materials, metalic foils, plywood, composites, leather, etc.
•
The abrasive application is used for harder materials: Metals, Glass, Stone, Concrete, Glass composites, Ceramics and hard materials like Aluminum oxide or Silicone Oxide.
VIII.
•
The only material that cannot be cut is Toughened Glass.
•
It is widely used in preparations of inlays for floorings and furniture.
y
It is the preferred method when the materials being cut are sensitive to high temperatures.
ADVANTAGES OF WATERJET CUTTING ¾ Environmentally friendly ¾ Can cut complicate shapes ¾ Better material utilization ¾ Cutting in all axes ¾ High speeds for various materials ¾ Easily adaptable to automatic contouring ¾ Easy programming with standard CAD/CAM systems ¾ Only simple fixtures required ¾ No heat affected zones ¾ Stress free cutting ¾ No material jump-off ¾ No tool sharpening ¾ No dust, fumes, or gases released
IX.
CONCLUSION ¾ WATER JET does not create a burr or HAZ as the heat cutting processes do. This saves expenses for secondary operations. ¾ WATER JET is slower than heat cutting techniques in nonconductive materials and similar for conductive materials like aluminum.
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¾ WATER JET has almost unlimited thickness capability whereas high powered plasma is limited to about 2” and laser to about 0.75” thick.
REFERENCES: 1. R.K.Rajput, “Fluid Mechanics and Hydraulic Machines, Part-2”, by S.Chand Publication, ISBN:81-219-1668-2, pp.1286-1287. 2. M.K. Jackson and T.W. Davies, “Conclusions, Nozzle Design For Coherent Water Jet Production”, Proceedings of the Second U.S. Water Jet Conference, May 24-26, 1983, pp.73 3. Flow International Corporation, “Waterjet White Paper”, Waterjet Seminar, pp.24. 4. Water Jet Cutting- A Technology on the Rise (2010)1-12 e-book:www.kmtwaterjet.com/ 5. Abrasive water jet Machining -Chuck Gallant (2009) e-book: www.waterjets.org/ 6. Water jet Cutting-Application and Capability (2004):www.waterjetparts.com/
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STEGANOGRAPHY Arihant Gaggar, Kapil Manek, Nachiket Jain Thakur College of Engineering, Kandivali, Mumabi, India kapil.km.kapil@gmail.com
Abstract Steganography is the art of hiding the information within the carrier file such as image, audio, etc. in such a way that the carrier would appear as an ordinary file to the intruders.Steganography is the writing hidden messages in such a way that no
one apart from the sender and intended
recipient even realizes that there is a hidden message. By contrast, cryptography obscures the meaning of a message, but it does not conceal the fact that there is a message.
I. INTRODUCTION Today, the term steganography includes the concealment of digital information within computer files. For example, the sender might start with an ordinary-looking image file, then adjust the color of every 100th pixel to correspond to a letter in the alphabetâ&#x20AC;&#x201D;a change so subtle that someone who isn't actively looking for it is unlikely to notice it. Steganalysis is the detection of the hidden information present in a carrier. It is the art of discovering and rendering useless such covert messages. Steganalysis can be divided into two parts: Passive and Active. Passive Steganalysis involves only detection of the presence of hidden information or a modified carrier whileActive Steganalysis involves extracting the hidden information as well. Our system works on Passive steganalysis. Steganalysis techniques produce some discernible change in the file size, statistics or both. These changes can manifest themselves in color variations, loss of resolution and other distortions that are visible to the human eye. The purpose of this project is to implement the tool which will embed a secret message (which might be a copyright mark, or a covert communication, or a serial number) in a cover message (such as an audio recording, or digital images, or the video files, etc) and provide the highly private and secure data transfer without third party intervention.Applications of steganography include protection against detection (data hiding) & protection against removal that seem to hold promise for copyright protection, tracing source of illegal copies, etc.
II.
STEGANOGRAPHY BASICS
Steganography literally means covered writing. Steganography simply takes one piece of information and hides it within another file like images contain unused or insignificant areas of data. Steganography certainly has beneficial advantages. It is an effective tool for protecting personal
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information. Steganography has its place in the security. On its own, it won’t serve much but when used as a layer of cryptography; it would lead to a greater security. Detection of covert communications that utilize images has become an important issue. So we are providing steganography using image, documents and audio as media, including security.
III.
HISTORY OF STEGANOGRAPHY
Hidden messages on messenger's body: also in ancient Greece. Herodotus tells the story of a message tattooed on a slave's shaved head, hidden by the growth of his hair, and exposed by shaving his head again. In the 20th century, invisible inks where a widely used technique. In the Second World War, people used milk, vinegar, fruit juices and urine to write secret messages. When Heated, these fluids become darker and the message could be read. Giovanni Batista Porta described how to conceal a message within a hard boiled egg by writing on the shell with a special ink made with an ounce of alum and a pint of vinegar. The solution penetrates the porous shell, leaving no visible trace, but the message is stained on the surface of the hardened egg albumen, so it can be read when the shell is removed. The first recorded uses of steganography can be traced back to 440 BC when Herodotus mentions two examples of steganography in The Histories of Herodotus. Demaratus sent a warning about a forthcoming attack to Greece by writing it directly on the wooden backing of a wax tablet before applying its beeswax surface. Wax tablets were in common use then as reusable writing surfaces, sometimes used for shorthand. Another ancient example is that of Histiaeus, who shaved the head of his most trusted slave and tattooed a message on it. After his hair had grown the message was hidden. The purpose was to instigate a revolt against the Persians
IV.
STEGANOGRAPHIC SYSTEM Fig 1
Modular Description ¾ Message File: The data to be concealed. ¾ Cover File: The file which will be used to hide the message (also called a carrier or a container. ¾ Secret Key: The Secret Key with the help of which the hidden message in a cover signal can be extracted at the receiving side. It is used as secured key. ¾ Steganography Tool: This module is to embed the message one wants to hide within the carrier using a steganographic technique which give Stego-file as output. ¾ Stego-file: The Stego-file is output of the System at sender end and input at the receiver end. ¾ Communication Channel: The Communication Channel is any transmission medium.
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Fig 1
V.
STEGANOGRAPHIC TECHNIQUES A. Physical steganography Steganography has been widely used, including in recent historical times and the present day. Possible permutations are endless and known examples include: Hidden messages within wax tablets â&#x20AC;&#x201D; in ancient Greece, people wrote messages on the wood, then covered it with wax upon which an innocent covering message was written
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Hidden messages on messenger's body — also used in ancient Greece. Herodotus tells the story of a message tattooed on a slave's shaved head, hidden by the growth of his hair, and exposed by shaving his head again. The message allegedly carried a warning to Greece about Persian invasion plans. This method has obvious drawbacks, such as delayed transmission while waiting for the slave's hair to grow, and the restrictions on the number and size of messages that can be encoded on one person's scalp.
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During World War II, the French Resistance sent some messages written on the backs of couriers using invisible ink.
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Hidden messages on paper written in secret inks, under other messages or on the blank parts of other messages.
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Messages written in Morse code on knitting yarn and then knitted into a piece of clothing worn by a courier.
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Messages written on envelopes in the area covered by postage stamps.
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During and after World War II, espionage agents used photographically produced microdots to send information back and forth. Microdots were typically minute, approximately less than the size of the period produced by a typewriter. World War II microdots needed to be embedded in the paper and covered with an adhesive, such as collodion. This was reflective and thus detectable by viewing against glancing light. Alternative techniques included inserting microdots into slits cut into the edge of post cards.
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During World War II, a spy for Japan in New York City, Velvalee Dickinson, sent information to accommodation addresses in neutral South America. She was a dealer in dolls, and her letters discussed how many of this or that doll to ship. The stegotext was the doll orders, while the concealed "plaintext" was itself encoded and gave information about ship movements, etc. Her case became somewhat famous and she became known as the Doll Woman.
Cold War counter-propaganda. In 1968, crew members of the USS Pueblo intelligence ship held as prisoners by North Korea, communicated in sign language during staged photo opportunities, informing the United States they were not defectors, but rather were being held captive by the North Koreans. An example of above explanation is given below:
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Within this picture, the letter positions of a hidden message are represented by increasing numbers (1 to 20), and a letter value is given by its intersection position in the grid. For instance, the first letter of the hidden message is at the intersection of 1 and 4. So, after a few tries, the first letter of the message seems to be the 14th letter of the alphabet; the last one (number 20) is the 5th letter of the alphabet. B. Digital Steganography Modern steganography entered the world in 1985 with the advent of the personal computer being applied to classical steganography problems. Development following that was slow, but has since taken off, going by the number of "stego" programs available: Over 800 digital steganography applications have been identified by the Steganography Analysis and ResearchCenter. Digital steganography techniques include: •
Concealing messages within the lowest bits of noisy images or sound files.
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Concealing data within encrypted data or within random data. The data to be concealed is first encrypted before being used to overwrite part of a much larger block of encrypted data or a block of random data (an unbreakable cipher like the one-time pad generates ciphertexts that look perfectly random if you don't have the private key).
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Concealed messages in tampered executable files, exploiting redundancy in the targeted instruction set.
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Pictures embedded in video material (optionally played at slower or faster speed).
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Changing the order of elements in a set.
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Content-Aware Steganography hides information in the semantics a human user assigns to a datagram. These systems offer security against a non-human adversary/warden.
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Blog-Steganography. Messages are fractionalized and the (encrypted) pieces are added as comments of orphaned web-logs (or pin boards on social network platforms). In this case the selection of blogs is the symmetric key that sender and recipient are using; the carrier of the hidden message is the whole blogosphere.
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Modifying the echo of a sound file (Echo Steganography)
Example:
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Image of a tree. Removing all but the two least significant bits of each color component produces an almost completely black image. Making that image 85 times brighter produces the image below.
C. Printed Steganography Digital steganography output may be in the form of printed documents. A message, the plaintext, may be first encrypted by traditional means, producing a ciphertext. Then, an innocuous covertext is modified in some way so as to contain the ciphertext, resulting in the stegotext. For example, the letter size, spacing, typeface, or other characteristics of a covertext can be manipulated to carry the hidden message. Only a recipient who knows the technique used can recover the message and then decrypt it. Francis Bacon developed Bacon's cipher as such a technique.
VI.
APPLICATIONS •
Usage in modern printers
Steganography is used by some modern printers, including HP and Xerox brand color laser printers. Tiny yellow dots are added to each page. The dots are barely visible and contain encoded printer serial numbers, as well as date and time stamps. •
Alleged use by terrorists
When one considers that messages could be encrypted steganographically in e-mail messages, particularly e-mail spam, the notion of junk e-mail takes on a whole new light. Coupled with the "chaffing and winnowing" technique, a sender could get messages out and cover their tracks all at once. Despite this, there are no known instances of terrorists using computer steganography. Al Qaeda's use of steganography is somewhat simpler: In 2008 a British man, Rangzieb Ahmed, was alleged to have a contact book with Al-Qaeda telephone numbers, written in invisible ink. He was convicted of terrorism. •
Alleged use by intelligence services
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In 2010, the Federal Bureau of Investigation revealed that the Russian foreign intelligence service uses customized steganography software for embedding encrypted text messages inside image files for certain communications with "illegal agents" (agents under non-diplomatic cover) stationed abroad.
VII.
CONCLUSION
Thus we would like to conclude that stegonagraphy is like a two edged sword. Its applicationsrange from all the frontiers for intelligence services and also do aid the likes of the infamous terrorist. Stegonagraphy is an emerging trend in the field of data security and encryption.The advantage of steganography, over cryptography alone, is that messages do not attract attention to themselves. Plainly visible encrypted messagesâ&#x20AC;&#x201D;no matter how unbreakableâ&#x20AC;&#x201D;will arouse suspicion, and may in themselves be incriminating in countries where encryption is illegal. Therefore, whereas cryptography protects the contents of a message, steganography can be said to protect both messages and communicating parties.
REFERENCE 1. Wayner, Peter (2002). Disappearing cryptography: information hiding: steganography & watermarking (http:/ / 2. www. wayner. org/ node/ 6). Amsterdam: MK/Morgan Kaufmann Publishers. ISBN 1-55860769-2. 3. http:/ / www. dmoz. org/ Computers/ Security/ Products_and_Tools/ Cryptography/ Steganography/ 4. Information Hiding: Steganography & Digital Watermarking. http:/ / www. jjtc. com/ Steganography 5. http://www.wikipedia.org/stegonagraphy/
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