Biannually-Published Newsletter of the
ISSUE
05
DEPARTMENT OF ELECTRICAL & COMPUTER ENGINEERING
Spring 2010
University of Nicosia
Get Tuned
Data Compression Power Engineering in the Department
♦ The Large Hadron Collider
By Dr Ioannis Kyriakides
By Dr Andreas Michaelides With the general aim of continuously widening the topic areas in the engineering department hence providing the students with further opportunities on the industrial market new courses amongst others in power engineering have been introduced in the curriculum.
♦ Data Compression
Right after taking a picture or recording a video the information from the natural world is converted into small atoms of information, called bits. In this form, the picture or video can be stored on a memory stick or a hard-disk where it can be later retrieved. It can also be transmitted over the internet to be received at a distant location.
The new courses are: • Electric Machines • Power System Analysis • Power Electronics • Electric Power Generation • Power System Protection
♦ Functional MRI ♦ A Cartender System frequencies. Consider for example an instrument playing a single note for a certain period of time, say 5 seconds. This corresponds to a single frequency for 5 seconds. One way to store this note is to take samples of this sound at an interval that should be at least twice as fast
Consequent intention of the department is to support these courses by the appropriate laboratory experiments to practically demonstrate and reveal major functional concepts. For the above purpose the department has recently purchased an electromechanical training system from LabVolt to support the course of Electric Machines and promote hence the wider establishment of power engineering in the department. The training system includes all major types of electric machines ranging from the transformer to the DC motor/generator, universal motor, induction motor up to the synchronous motor/generator providing thus the student with the basic knowledge about conventional industrial production processes. All machines are rated about 200W. The system provides also apart from several standard power system components as capacitors, inductors etc. also a 0 to 416V three phase and a 0 to 400V DC variable power supplies. Finally the system can simulate all mechanical processes through a data acquisition module on the computer.
as the frequency of the note (according to the sampling theorem). Let’s assume then that over a period of 5 seconds we have taken 10,000 samples. These are numbers that we can store in a large data file. Looking at the signal, however, in another domain (in this case the frequency domain) we should only store or sent only one number in To elaborate on this further, let’s start order to later be able to retrieve this note. with a simple example: Have you ever wondered, however, how these complex shapes and colors in a picture or a video can be summarized and fit on a relatively small file? The trick is that these complex shapes and colors can be converted into a different form. This new form is simpler and can be described with a very few bits of information.
Consider a sound that you would like to record. This sound is made of notes, or frequencies. Consider for example an
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The unknown particle What exactly is this mysterious particle that scientists call Higgs Boson and some people have named it as the “God Particle�?
The Higgs Boson is a very small particle, which interacts with a field called the Higgs Field. This field creates a "drag" on particles, and this drag gives the particles mass. An easy way to think of, is that this field grabs onto many other particles, giving them a resistance to being moved. This resistance is observed as the particle's mass. This field only interacts with particles with mass, which is why some particles can go the speed of light like photons and some cannot, like neutrons. As it is much smaller than other particles, it is difficult to detect. The Large Hadron Collider at CERN is the tool that scientists are using to find it. These particles do not obey the conservation of energy, which is allowed so long as they exist for a very short time- much less than a septillionth second. The collider will have so much energy that it should be able to give these particles the energy they need to obey the conservation of energy, and not disappear. However, since the Higgs has so much mass, it takes a lot of energy to create one. Its existence is required in the Standard Model, but has yet to be found. If the Higgs does not exist, then it will require an entire rewrite of physics.
Source: http://wikipedia.org
The Large Hadron Collider (LHC) and the hunt for the Higgs Boson By Dr Marios Nestoros
The Large Hadron Collider is probably the biggest machine ever built on Earth. One can imagine it is a circular tube with a circumference of 26 659 m at a depth of 100 m below the surface of earth, near the French-Swiss border at Geneva. In this tube two proton beams moving in opposite directions and accelerated in steps with the aid of electric fields (the same principle of accelerating electrons in the old type television set) will achieve very high speed (99.99% of the speed of light) and kinetic energy, after circulating thousands of times per second around the loop and then will finally collide head on. The guidance and focusing of the two opposing beams is achieved with the aid of specially designed superconducting magnets. Altogether some 600 million proton collisions will take place every second. This will induce a temperature more than 100 000 times hotter than the heart of the Sun, concentrated within a minuscule space region. In this manner the collisions will replicate the high density and temperatures during the Big Bang, offering the scientists the chance to check their theoretical models. One of the main purposes of the experiment is to shed light on the internal structure of protons (similar to the idea of breaking a box to find out what is hidden inside) and bring the finest physical theory we have until now; the Standard Model to its limits. The Standard Model is a physical theory that describes the world in terms of three (electromagnetic, strong, weak) out of
the four fundamental forces (or interactions) and their particles. The Standard Model leaves out the fourth interaction which is our well known gravity but this is not a problem when we investigate the world of the very small, where the effect of gravity is negligible. The four interactions manifest themselves via the exchange of their corresponding particles. For example the electromagnetic force between electrically charged objects can be understood via the exchange of photons and the strong force via the exchange of gluons. Although the Standard Model describes very well the world around us it cannot yet incorporate gravity and answer the question of the missing anti-matter and the existence of dark energy. In addition to the above missing links the Standard Model predicts the existence of a particle called the Higgs (from the name of the physicist Peter Higgs who proposed it) boson. This particle is very important for the Standard Model since it explains the mechanism through which the rest of the particles attain mass. Scientists expect to detect the Higgs Boson during the experiments to be performed with the LHC.
On Friday 19th of March, 2010 CERN This Issue’s Q& has announced that the two protons beams have circulated at full energy (3.5 TeV) around the ring. This means that very soon the actual experiment (head on collision of the beams) will take place. The generated data (types of particles, their energy and direction of motion among others) recorded by each of the big experiments at the LHC will fill around 100 000 dual layer DVDs every year. Thousands of scientists all around the world will analyze the data over the next 15 years with the aid of a distributed computing network called the Grid, involving tens of thousands of computers. Sources http://public.web.cern.ch/public/en/LHC/LHC-en.html http://lhc.web.cern.ch/lhc/
Functional Magnetic Resonance Imaging (fMRI) By Dr George Gregoriou Introduction Functional magnetic resonance imaging, or fMRI, is a technique for measuring brain activity. It works by detecting the changes in blood oxygenation and flow that occur in response to neural activity – when a brain area is more active it consumes more oxygen and to meet this increased demand blood flow increases to the active area. FMRI can be used to produce activation maps showing which parts of the brain are involved in a particular mental process.
The development of fMRI in the 1990s, generally credited to Seiji Ogawa and Ken Kwong, is the latest in long line of innovations, including positron emission tomography (PET) and near infrared spectroscopy (NIRS), which use blood flow and oxygen metabolism to infer brain activity. As a brain imaging technique fMRI has several significant advantages: 1. It is non-invasive and doesn’t involve radiation, making it safe for the subject. 2. It has excellent spatial and good temporal resolution. 3. It is easy for the experimenter to use. The attractions of fMRI have made it a popular tool for imaging normal brain function – especially for psychologists. Over the last decade it has provided new insight to the investigation of how memories are formed, language, pain, learning and emotion to name but a few areas of research. FMRI is also being applied in clinical and commercial settings.
Background FMRI is one of the most recently developed forms of neuroimaging but the idea underpinning the technique inferring brain activity by measuring changes in blood flow - is not new. It was in 1948 in a seminal experiment measuring oxygen metabolism and blood flow in the brain that Seymour Kety and Carl Schmidt confirmed that blood flow in the brain is regionally regulated by the brain itself. They demonstrated that when neurons use more oxygen, chemical signals cause nearby blood vessels to dilate. The increase in vascular volume leads to a local increase in blood flow. At the time of these publications Kety and Schmidt were considered vascular physiologists more than brain scientists. Nevertheless the ability to measure CBF, a proven correlate of brain metabolism, opened up the remarkable possibility of studying brain function in humans.
What does MRI measure? The cylindrical tube of an MRI scanner houses a very powerful electromagnet. A typical scanner has a field strength of 3 Teslas (T), about 50,000 times greater than the Earth’s field. The magnetic field inside the scanner affects the magnetic nuclei of atoms. Normally atomic nuclei are randomly oriented but under the influence of a magnetic field the nuclei become aligned with the direction of the field. The stronger the field the greater the de-
EYE ON TECHNOLOGY Solar Impulse! Wouldn't it be great to be able to drive for hours without having to stop for gasoline? How about not needing gasoline at all? A solar car could provide transportation using free fuel straight from the sun! But why stop there? Airplanes could also use solar power cutting airfare costs and saving the environment. All these sound great. But how about driving when it's cloudy or at night. And you certainly wouldn't want your plane to run out of fuel in the middle of the night (right above the Atlantic to make it more dramatic!). Well, all these worries are starting to fade away. A solar plane made by the Solar Impulse team and steered by Andre Borschberg has flown through the night! The plane’s batteries were charged during the day and the charge was sufficient to fly the aircraft all night. This, according to the team, proves that a plane can fly perpetually, without ever needing to refuel. And, of course, this is just the beginning. The solar airplane is made of carbon fiber, uses an on-board system to optimize energy consumption, and is equipped with wings that span 61 meters and are covered with solar panels. The next goal is to circumnavigate of the globe by 2013. The only limit that remains... is the sky!
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Sources http://news.bbc.co.uk http://www.solarimpulse.com
Did you know?
An ECE Student Final Year Project: A Cartender System
Radar, Sonar and Bats Did you know that radar is an acronym for RAdio Detection And Ranging? Did you also know that sonar comes from SOund Navigation And Ranging? Both a radar and a sonar system emit waveforms which bounce off obstacles (targets) and return to the system. The system then processes the return waveform to identify the distance and velocity of the target with respect to the system. This is accomplished by identifying the time it takes for the waveform to return (distance) and the frequency change or time scaling in the waveform (velocity). Radar works with electromagnetic waves in the atmosphere. Sonar, on the other hand, uses sound waves and is most often used underwater.
Did you know that bats use a form of sonar to avoid obstacles and locate pray? Bats are equipped with an echolocation system that can produce a map of their surroundings. This system possesses such processing power as to enable bats to navigate through dark caves and pinpoint the location of insects in real time. Such a sonar system is envied by engineers building the most advanced human made sonars. Therefore, engineers study bats in order to improve sonar and radar systems. Bats emit high frequency acoustic sounds through their mouth or nose. The bat’s large ears pick up the sounds and identify their time delay, Doppler, and angle of arrival. From the time it takes for the sound to travel from the bats mouth to the target object or insect and back to the bat’s ear, the bats can tell how far the target is. Moreover, due to the Doppler effect, a change in the frequency of the returning sound, reveals how fast the target is moving with respect to the bat. Using distance, velocity, and the angle of arrival, bats get plenty of information about their surroundings. This makes them excellent hunters possessing both maneuvering speed and surveillance capabilities.
By Mr Demetris Demetriou One meaning of the word “tender” is to be considerate and protective. This project, the Cartender System does just that in the context of a car and anyone driving it. The system initially evolved as a means of communicating between cars moving in the roads and the premises of the owner / administrator which could be many kilometers away. As time passed, it was realized that the necessary infrastructure to implement such a system could be used as a platform for various modules which would make the system very powerful and reveal a plethora of unforseen configurations and applications. The system is comprised of: 1. a server application which maintains databases and relays information from mobile vehicles to the remote administrator and back, 2. an administrator management application which monitors and controls vehicle statuses and communicates with the vehicles,
Mr. Demetriou, a graduating student of the Electronics Engineering Program, has presented his Final Year Project during the spring semester 2010, under the supervision of Dr. Antonis Hadjiantonis.
3. an onboard computer located inside the mobile vehicle, which: (a) retrieves vehicle information from the car (like engine parameters, driver alcohol intake etc.), (b) retrieves information from the server (like specific driver constraints and settings), and (c) communicates the above between the vehicle and the server.
Vehicle (carrying the onboard computer)
Figure 1 System communications … continued on page 5
Data Compression Data Compression This number is simply the frequency of the note! This is the essence of what we call data compression. We find a smarter way of describing the data, by looking at them from a different point of view. The same concept extents to more complex sounds like music. Any sound can be represented by a certain limited number of frequencies that can be saved or transmitted and be later reconstructed to create audible sound. In the case of pictures, consider a 12 mega pixel picture that you take with your digital camera. 12 mega pixels correspond to 12 million pixels, with each pixel carrying color and intensity information! That is a lot of data to store. Transforming the picture, however, into another domain, usually the discrete cosine domain, one can see that only a few numbers can represent
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all the information contained in the pixels. Storing or transmitting those few numbers and then converting them back to the spatial domain of 12 million pixels, one can see the exact picture originally taken. In summary, data compression techniques enable us to take color pictures and video, store them in tiny memory cards, and send them by email to friends. Also data compression allows us to store songs in very small file sizes, compared to the past. This enables their easy downloading from websites or sharing them (legally of course!).
Picture Courtesy: http://en.wikipedia.org/wiki/File:A_photograph er_on_the_ruins_of_Sutro_Bath.jpg
An ECE Student Final Year Project: A Cartender System Communication is achieved via a continuous internet connection which allows data to be exchanged between the car, the remote server and the monitoring computer (see Figure 1). The server application allows the control of many cars from many administrators and provides stability to the system. An interesting feature is that in our case, and for minimizing Operations Expenditures (OPEX), the server is located in the USA (thousands of kilometers away). Various personal authentication methods make the car acknowledge which user is using it. This is necessary for security purposes, for monitoring, but also to prepare the car’s setting for that specific user. In our project, this was achieved by interfacing the car electronics with the on board computer. The driver uses his/her USB stick (with a unique ID) and then inserts a personal password. These allow the car to uniquely identify the user, and send this info to the administrator management system (via the server). Then, the onboard computer inputs and outputs allow the controlling/monitoring of various car parameters like driver alcohol level, starter status, rear view mirror position and so on.
Figure 2 The Administrator Management Screen
status, sensor readings, sensor statuses, etc). Our prototype retrieved only the speed and engine rpm but due to its modular design it can easily encompass more parameters.
Figure 3 Tray notifications on speed limit
The remote transmission enable the Administrators (in our project these are called Controllers) know which cars are occupied, which are the drivers driving them, and under what circumstances the cars are driven (e.g. is the driver speeding or has the driver sped some hours ago?) and so on, using a simple color coding scheme (Figure 2). This effectively allows them to remotely monitor the car usage and impose restrictions if necessary. Figure 3 depicts a notification which pops up on the administrator’s application notifying that a specific driver has exceeded the [administrator-set] speed-limit. Similarly, Figure 4 depicts a log file which records all events that took place during a driver’s session in a car.
Figure 4 Log file on events
The most important (and difficult) part was to retrieve information from the On Board Diagnostics (OBD) port of the car. The OBD port uses specific standards to output a wealth of car related information for monitoring and error retrieving purposes. The parameters provided by the OBD port are numerous, (velocity, rpms, fuel
Virtual Dashboard (the cartender GUI) To make the Cartender Administrator Management application more interesting we built a simple, but smart GUI application called the Virtual Dashboard. This application displays car engine information in a realistic manner and creates the feeling that the administrator is actually looking at the monitored car’s dashboard readings. The Virtual Dashboard updates its readings every second (a system variable). This is depicted in Figure 5. The Cartender System is ultimately two systems in one. It is a remote monitoring system, that conveys various information from and towards the monitored car and it is a user management system, which uses authentication mechanisms to identify users and customize various car aspects according to their needs and imposed restrictions. Our initial tests indicated that end-to-end communication between the car and a laptop computer running the administrator management system (with mobile internet connection) takes about one second to complete when the server is USbased. We feel that this is more than satisfactory as our application is not real-time critical and anticipate the delay to significantly drop as mobile internet technologies evolve and Cyprus server prices drop. In conclusion, although the project is not inventing anything new, it is blending existing and until now unrelated technologies like the OBD, the Internet, and hardware interfacing, which creates new and unforeseen applications. An example of a possible application is a Fleet Management System, which can monitor crucial information on multiple vehicles such as engine errors, fuel levels and mileage to next service, thus enabling the organization to save thousands of euros from preventive measures. A second application would be parents preventing their children from driving while under the influence of alcohol.
If you would like more information on this project, you may contact:
Figure 5 The Virtual Dashboard
Mr. Demetris Demetriou at soundbynibs@hotmail.com
Department of Electrical & Computer Engineering
Functional Magnetic Resonance Imaging (fMRI) …continued from page 3
Clinical and commercial use of fMRI FMRI now has a small but growing role in clinical neuroimaging. It is used in pre-surgical planning to localize brain function. There is also potential for clinical fMRI in applications including presymptomatic diagnosis, drug development, individualization of therapies and understanding functional brain disorders. Early studies also suggest that fMRI has the potential to be used as bio-feedback for conditions such as chronic pain. Therehave been several early ventures to capitalize on fMRI. Two companies have been setup in North America offering lie detection services using fMRI. They are No Lie MRI, Inc and Cephos Corporation. There are also several neuromarketing companies such as California-based Sales Brain and Oxford start-up Neurosense, using fMRI to gain insights into consumer thought and behavior.
gree of alignment. When pointing in the same direction, the tiny magnetic signals from individual nuclei add up coherently resulting in a signal that is large enough to measure. In MRI, it is the magnetic signal from hydrogen nuclei in water (H2O) that is detected. The key to MRI is that the signal from hydrogen nuclei varies in strength depending on the surroundings. This provides a means of discriminating between grey matter, white matter and cerebral spinal fluid in structural images of the brain. What does fMRI measure? Oxygen is delivered to neurons by haemoglobin in capillary red blood cells. When neuronal activity increases there is an increased demand for oxygen and the local response is an increase in blood flow to regions of increased neural activity. Haemoglobin is diamagnetic when oxygenated but paramagnetic when deoxygenated. This difference in magnetic properties leads to small differences in the MR signal of blood depending on the degree of oxygenation. Since blood oxygenation varies according to the levels of neural activity these differences can be used to detect brain activity. This form of MRI is known as blood oxygenation level dependent (BOLD) imaging.
Department of Ele ct r ic a l an d Computer Engineering UNIVERSITY OF NICOSIA 46 Makedonitissas Avenue P.O. Box 24005 1700 Nicosia CYPRUS (+357) 22841500 phone (+357) 22357481 fax ece@unic.ac.cy www.ece.unic.ac.cy
One point to note is the direction of oxygenation change with increased activity. You might expect blood oxygenation to decrease with activation, but the reality is a little more complex. There is a momentary decrease in blood oxygenation immediately after neural activity increases, known as the “initial dip” in the haemodynamic response.
This is followed by a period where the blood flow increases, not just to a level where oxygen demand is met, but overcompensating for the increased demand. This means the blood oxygenation actually increases following neural activation. The blood flow peaks after around 6 seconds and then falls back to baseline, often accompanied by a “poststimulus undershoot”.
Activation maps The image shown above is the result of the simplest kind of fMRI experiment. While lying in the MRI scanner the subject watched a screen which alternated between showing a visual stimulus and being dark every 30 second. Meanwhile the MRI scanner tracked the signal throughout the brain. In brain areas responding to the visual stimulus you would expect the signal to go up and down as the stimulus is turned on and off, albeit blurred slightly by the delay in the blood flow response. The ‘activity’ in a voxel is defined as how closely the time-course of the signal from that voxel matches the expected timecourse. Voxels whose signal corresponds tightly are given a high activation score, voxels showing no correlation have a low score and voxels showing the opposite (deactivation) are given a negative score. These can then be translated into activation maps. Images from fMRI experiments are often presented in color to make it easier to visualize results. Reference: http://www.fmrib.ox.ac.uk/education/fmri