Miloš Žefran, ECE; Matteo Corno, ECE; Maxim Kolesnikov, ECE Primary Grant Support: NSF; UIC College of Dentistry
Problem Statement and Motivation •
New surgical procedures are introduced at a high rate. Each requires costly training.
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Haptic simulators provide a cost-effective alternative to traditional training: no need to travel, 24/7 availability, easy to create additional units as needed.
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Existing paradigm for haptics is not suitable for teaching sensorimotor skills. Lack of good models and of realistic haptic rendering are main obstacles to creating useful simulators.
Key Achievements and Future Goals
Technical Approach Position and force information are simultaneously displayed to facilitate motor skill acquisition. The user is modeled as a three-input, single-output system.
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Developed a new paradigm for teaching of sensorimotor skills with haptics.
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Proposed a new model for a user responding to haptic and visual stimuli. The model experimentally verified.
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The model of the human enables stability analysis through the Lyapunov second method; traditional passivity techniques can not be used. Time delays are critical for stability and are explicitly modeled.
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Stability analysis of the system performed. Stability boundaries explicitly identified.
•
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Implemented a new method for haptic rendering.
The Euclidean group SE(3) used to develop haptic rendering algorithms that properly account for translations and rotations. Kinetic energy provides an intrinsic way to define the penetration which is in turn used to compute the reaction force.
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Future work: applications in medical training, rehabili-tation; faster implementation of the haptic rendering; implementation on cheap haptic displays; extensions of the new paradigm for collaborative haptics.
•
Investigators: Mitra Dutta, ECE; Michael Stroscio, ECE, BioE, Physics Primary Grant Support: AFSGO
Problem Statement and Motivation •
Mercury ions and other heavy metals are found in environmental waters, which can lead to toxicity in humans
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A rapid detection method for environmental monitoring and exposure levels in humans is needed
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Engineering a nanoconstruct to detect these heavy metals in fluids can be done using quantum dots and single stranded DNA
Hg 2+ 10000
: eFluor® 650NC
: DNA aptamer
Intensity (a. u.)
: Nanogold : Hg 2+
0 Hg
5000
500 nM Hg 824 mM Hg
0 600
650
700
Wavelength (nm)
Key Achievements and Future Goals
Technical Approach •
DNA aptamers used as molecular recognition elements in sensing strategies for ions and biomolecules
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Mercury ions were detected using a spectrometer to measure the fluorescence intensity of the QD
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Aptamers can perform like antibodies with affinity to a wide range of targets which can result in a conformational change as in the figure
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Detection is achieved in the nanomolar range, while higher levels of mercury were shown to interfere with QD fluorescence
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Quantum dots (QD) are robust and stable fluorophores and gold nanoparticles are stable quenchers
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Future targets include lead, zinc, and cadmium, which have been shown to interact with specific DNA aptamers
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Conjugating QDs and gold nanoparticles to aptamers provides the detection signal
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Optical detection platform to be applied to biomarkers
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Translate detection assay to portable handheld device
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Surface energy transfer between QD and gold nanoparticle is the mechanism for optical detection
James C. Lin, PhD, Electrical and Computer Engineering; and Bioengineering Primary Grant Support: Magnetic Health Science Foundation
Problem Statement and Motivation •
Wide Spread Use of Cell Phone Technology
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Concerns about Health and Safety
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Plectin is A High Molecular Weight Protein
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Plectin Immunoreactivity Follows Brain Injury
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Mutation of Plectin Identified With Signs of Disorder
Neurodegenerative
Immunolabeling of Irradiated Rat Brain Using Monoclonal Antibody, Pletin.
Key Achievements and Future Goals
Technical Approach •
Irradiate Young Adult Rats (300 g) in Plexiglass Holder
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Immunolabeling of Irradiated Rat Brain Showed Increased Glial Fibrillary Acidic Protein (IFAP)
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Produce Power Deposition Patterns in Rat Brains Comparable to Those in Humans
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GFAP Plays An Important Role in Glial Reactions After Lesions
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Brains Were Removed and Incubated
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Floating Sections Were Used for Immunocytochemistry
Preliminary Results Indicate There is No Difference in Expression Pattern of Plectin Among the Brains Tested at Peak SAR levels of 0, 1.6 and 16 W/kg in the brain.
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Use Monoclonal Antibody - plectin - Labeling
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Additional Experiments to Establish Statistical Validity
•
Examination by Light Microscopy
James C. Lin, Electrical and Computer Engineering and Bioengineering Primary Grant Support: Magnetic Health Science Foundation 64MHz
200MHz
300MHz
340MHz
Problem Statement and Motivation
400MHz
To analyze the physiological response of radiofrequency (RF) power deposition during magnetic resonance imaging (MRI) with headspecific volume coils.
Key Achievements and Future Goals
Technical Approach FDTD methods are used to calculate RF power deposition and temperature elevation in MRI of the human head within volume coils from 64–400 MHz at different power levels both with and without consideration of temperature- induced changes in rates of metabolism, perspiration, radiation, and perfusion.
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At the highest power levels currently allowed in MRI for head volume coils, there is little effect from the physiological response.
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To assess the possibility that at higher power levels or in different types of coils (such as extremity or whole-body coils) the physiological response may have more significant effects.
Ishita Basu,ECE; Daniela Tuninetti,ECE; Daniel Graupe,ECE; Konstantin Slavin,Neurosurgery Primary Grant Support: Dr. Tuninetti’s start-up package.
Problem Statement and Motivation •
MOTIVATION: Deep Brain Stimulation (DBS) is a surgical method of relieving advanced stage Parkinson’s Disease (PD) patients of most of their debilitating symptoms (like tremor). DBS involves stimulating the area of the brain that controls movements with a high frequency train of electrical pulses through an implanted electrode.
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PROBLEMS: In today’s DBS systems the stimulation parameters are optimized manually by the physician with visual feedbacks from the patient. Moreover, the stimulation is continuous and constant over time.
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OBJECTIVES: 1) Design an intermittent deep brain stimulation instead of a continuous stimulation. This ensures lower power requirements, a longer battery life, and possiblye reduce damage to healthy neurons in PD patients. 2) Tune the parameters of the DBS (frequency, pulse amplitude, pulse duration) by employing a closed-loop control. This allows to tailor the DBS stimulation to each individual patients thus enhancing DBS efficacy.
Key Achievements and Future Goals
Technical Approach •
A cluster of actively firing neurons is modeled as a group of coupled oscillators that is mathematically described by stochastic differential (Langevin) equations.
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Simulation results shows that on an average a train of high frequency pulses with its frequency and/or amplitude stochastically modulated with Gaussian noise performs better than its deterministic counterpart.
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The signals measured from PD patients, such as the local field potential from the brain and the muscular potential from surface EMG, are modeled parametrically.
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Next, we will test the above hypothesis on a model with parameters extracted from actual measured signals.
• •
The signal parameters are adaptively estimated for each patient from the measured signals and to optimize the DBS stimulation parameters.
We will trace the evolution of the parameters extracted from the measured signals which will serve as a reference in the control loop.
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We will optimize the DBS stimulation parameters.
Primary Investigator: Hulya Seferoglu
Energy Efficiency in Cooperating Mobile Devices
Problem Statement and Motivation • Increasing popularity of applications such as video streaming in mobile devices introduces: • Higher demand for throughput; • Strain on cellular links. • Cooperation among mobile devices by exploiting both cellular and local area connections (WiFi, Bluetooth) is promising. • Popularity of applications exponential increase in data rates. • The energy per delivered bit needs to be reduced in cooperating mobile devices.
Technical Approach • Goal: Develop energy efficient cooperation schemes for mobile devices by taking into account energy consumption cost of mobile devices while maximizing throughput. • Approach: • Develop stochastic network control algorithms that take into account practical requirements of cooperating mobile devices. • Investigate energy consumption cost of mobile devices and its impact on the control algorithms. • Investigate energy storage (battery) levels of mobile devices. • Develop energy efficient stochastic network control algorithms for cooperating mobile devices.
Key Achievements and Future Goals • The PI has published several conference and journal papers in the broader area. • The PI is planning to submit a proposal on this topic.
Investigators: M. Dutta, ECE, M. Stroscio, ECE and BioE Primary Grant Support: AFOSR, ARO, NSF, SRC, DARPA, DHS Quantum Dots in MEH-PPV Polymer
Problem Statement and Motivation
Gold contacts •
Design, fabrication, characterization of QD-based photon-absorbing media embedded in conductive polymers for optoelectronic devices
•
For underlying concepts see group’s paper on “Applications of Colloidal Quantum Dots,” Microelectronics Journal, 40, 644-649 (2009).
ITO Glass
Top view MEH-PPV Polymer / CdSe Quantum Dot Composite
Key Achievements and Future Goals
Technical Approach •
Design of quantum-dot (QD) ensembles in conductive polymers
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Fabricating quantum-dot (QD) ensembles in conductive polymers
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Modeling electrical and optical properties including robustness and sensitivity to QD-QD separation
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Experimental characterization of integrated structures
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Multi-wavelength optoelectronics
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Numerous simulations of electrical and optical properties including robustness and sensitivity to QD-QD separation
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Numerous simulations for a variety of QD—conductive-polymer systems
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Current sensing AFM measurements of I-V curves for a variety of QDs embedded in conducting polymers
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Ultimate goal is realization of multi-wavelength photodetectors
P.I. Igor Paprotny Funding: new faculty startup, California Energy Commission
Problem Statement and Motivation • • •
•
•
Integrating discrete components on flexible substrates Using ultra low-power wireless radios and microcontrollers to implement low-power wireless networks Algorithms reconstruct system parameters from sparse (distributed) sensory data
Energy harvesting enables potentially perpetual operation of the sensor nodes
Key Achievements and Future Goals
Technical Approach • •
Low-power radios and ancillary electronics introduce the possibility of ubiquitous low-cost wireless sensor networks. Distributed sensors are predicted to be an integral part of our every day life Enable many important applications: • Energy systems sensing • Body sensor networks • Environment systems
• • •
Created a 4 mm x 4 mm sized low-power sensor node using discrete components Developed a self-calibrating current sensor system Future goals: • Develop a co-location system for 1 mm3 wireless sensor node • Integrate a wireless sensor network in underground coal mines • Create a smart bandaid body sensor node
Wenjing Rao, ECE department
Problem Statement and Motivation
Post-manufacturing defect-tolerant logic implementation on nano-crossbars • Models, algorithms, yield analysis
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Exploiting time / hardware / information redundancy at multiple design hierarchical levels and granularities • Logic gate level: nano-PLAs • Arithmetic level: fault tolerant adders • Processor architecture level: speculative computation based fault tolerance paradigm
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Redundancy sharing on a locally connected network • Flexible, dynamic assignment schemes • Network analysis
Future electronic systems on nanoscale devices
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Promises • Boosts of computational power • Wide application domains
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Challenges • Severe unreliability (manufacturing defects + run time faults) • Localized interconnect
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Need: • New system design and computational paradigms for constructing future reliable nanoelectronic systems.
Key Achievements and Future Goals
Technical Approach •
•
•
Low-cost defect / fault tolerance approaches exploiting • Reconfigurability • Multiple hierarchical levels and granularities • Regularity
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Decentralized resource allocation protocol on locally connected network • Low communication overhead • Scalable • Generalizable framework for self-adaptive systems
Rashid Ansari, ECE; Ashfaq Khokhar, ECE/CS Primary Grant Support: NSF, U.S. Army
Problem Statement and Motivation •
Real-time visual tracking is important in automated video scene understanding for applications such as surveillance, compression, and vision-based user interfaces
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Visual Tracking: Locate moving objects from visual cues.
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Low computation complexity (Real-time requirement)
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Tracking rapid motion, in presence of occlusion (self and foreign-body)
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Tracking multiple objects using multiple cues
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High dimensionality (articulated human body tracking)
Key Achievements and Future Goals
Technical Approach •
Combine particle filtering with efficiency of mean shift tracker.
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New formulation of visual tracking in a set theoretic framework.
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Graphical models (Markov Random Field and Bayesian Network) provide high-level modeling for single object and multiple object tracking in high-dimensional spaces.
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Real-time tracking with improved efficiency compared with the standard particle filter-based tracker by 20-40%.
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Improved performance with robust tracking under rapid motion
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Handles partial occlusion and short-time full-occlusion
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Naturally extends from single to multiple object tracking
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Convenient fusion of multiple cues (no pre-adjustment of tracker needed). Easy incorporation of additional cues.
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Application in foveated video compression and event recognition in scenes will be investigated
Jezekiel Ben-Arie, ECE Primary Grant Support: NSF
Problem Statement and Motivation This project is focused on the development of methods and interactive tools that enable efficient querying, recognition and retrieval of video clips in a video database of human motion. Natural and symbolic languages are not suited to accurately describe human motion.
An Example of a query composition of human activity along a trajectory. The humanoid then animates it for visual feedback.
Key Achievements and Future Goals
Technical Approach Our Approach: is to represent human motion by novel temporal scripts that define the 3D pose and velocity of important body parts. The human body is represented by an hierarchic structure. This enables not only efficient representation but also robust recognition from any viewpoint. The user is also allowed to interactively compose practically any desired motion query and to view it.
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An innovative method for human motion Recognition by Indexing and Sequencing (RISq) was developed. The RISq requires only few video samples. An interactive GUI based tool for composing articulated human motion was also established.
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This project has also broader Impacts. Since our interactive-graphic approach does not require reading or writing, it could be also applied to enhance the creativity and educational participation of groups such as children in authoring animated plays and movies.
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Our future goals is to extend the range of activities and the number of persons that can be composed. We are also extending our activity recognition system –RISq (which is currently patent pending) to include speech and object recognition.
Jezekiel Ben-Arie
Problem Statement and Motivation •
Key Achievements and Future Goals
Technical Approach •
The recognizer uses a novel approach called RISq (Recognition by Indexing and Sequencing) which requires for training only few stored exemplars for each word class. User can train the recognizer to user's personal speech in any language and accent simply by recording their vocabularies.
Developing a robust method for continuous speech recognition which can be easily trained to any speaker with any accent at any language and even several languages.
•
Achieved Recognition rates which are better than prevalent methods based on HMM. Currently improving training and recognition rates by developing additional phoneme classification.
Jezekiel Ben-Arie
Problem Statement and Motivation •
Key Achievements and Future Goals
Technical Approach •
Developed a novel approach Employing Tensor Recognition with additional improvements by a new Exemplar Compounding which enables to represent much larger variety of stored models with few exemplars
Developing a detection and recognition methods of various object and animal classes in a very large image database which includes a variety of these classes from different views, poses and partial occlusions.
•
Much better detection and recognition rates than the best known state of the art methods
Jezekiel Ben-Arie
Problem Statement and Motivation •
Key Achievements and Future Goals
Technical Approach •
Developing a novel method named RISq (Recognition by Indexing and Sequencing). RISq is recognizing sequences of vectors derived from the 3D skeletal joints of the humans tracked.
Recognize in Real time a large variety of Human Activities using 3D Video acquired by 3D Kinect Cameras.
•
Achieved Robust human activity recognition invariant to view points and action speeds. Recognition rates are much better than the prevalent HMM based approaches.
Natasha Devroye (ECE) NSF CAREER Award 1053933: Foundations of Two-way Communication Networks NSF CIF 1216825: Wireless Relay Networks: Coding Above Capacity and Exploiting Structure
Problem Statement and Motivation • • • •
•
Key Achievements and Future Goals
Technical Approach • •
We have devised a key technical tool: a lattice list decoder We tailor and devise new technical approaches to mimic random coding proofs using nested lattice codes
Random codes have traditionally been used to demonstrate the information theoretic achievability of rates in networks Structured codes such as lattice codes for Gaussian channels are more practical, and have linearity properties which classical random codes lack We know lattice codes may mimic random codes in certain single-hop scenarios (point-to-point, broadcast, multiple access channels) We know lattice codes surpass the known performance of random codes in certain scenarios (two-way relay channels, N>2 user interference channels) Question: can structured codes replace random codes in general networks, and furthermore achieve better rates?
•
• •
•
We have used this, and other careful manipulations to show that lattices may achieve the same rate as random codes as • The Decode-and-Forward rate of the relay channel • The Compress-and-Forward rate of the relay channel We have used the lattice list decoder to generalize two-way relaying schemes to two-way relaying scenarios with direct links Long-term goal: demonstrate that lattice codes may replace and improve upon random codes in Gaussian networks Y. Song and N. Devroye, ``Lattice codes for the Gaussian relay channel: Decode-and-Forward and Compress-and-Forward,’’ submitted to IEEE Trans. Information Theory, October 2011.
Natasha Devroye (ECE) NSF CAREER Award 1053933: Foundations of Two-way Communication Networks
Problem Statement and Motivation •
Classical information theory is suited to one-way communication
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In recent years much progress has been made in bounding the theoretical limits of one-way communication networks
• •
Communication is inherently two-way We ask: what is the fundamental performance of two-way networks?
Key Achievements and Future Goals
Technical Approach • • •
We approach two-way networks from an information theoretic perspective We seek the capacity region, or inner and outer bound to the capacity region of two-way networks We start by considering three simple two-way networks, and initially seek to characterize when the ability of nodes to adapt future transmissions (channel inputs) to past channel outputs does not increase capacity:
• • •
• • •
For certain deterministic two-way networks, were able to obtain capacity: showed that equal to two one=way channels in parallel Future goal: what is the most general class of network for which this holds? Future goal: When does adaptation (exploiting previously received outputs in two-way networks) help, when is it useless?
Z. Cheng, N. Devroye ``Two-way Networks: When Adaptation is Useless,’’ submitted to IEEE Trans. On Information Theory, June 2012. Z. Cheng, N. Devroye, ``On Constant Gaps for the Two-way Gaussian Interference Channel,’’ Allerton 2012. Z. Cheng, N. Devroye, ``On the Capacity of Mult-user Two-way Linear Deterministic Channels,’’ ISIT 2012.
Natasha Devroye (ECE) AFOSR FA9550-10-1-0239: ``Fundamental bounds on information fusion with focus on waveform-based intent detection and avoidance’’
Problem Statement and Motivation • •
•
•
Key Achievements and Future Goals
Technical Approach •
We use Directed Information (DI) as waveform scheduling metric
Numerous defense applications rely on closed-loop, or adaptive, information gathering systems As radar waveform generators and processing abilities become more capable, the question is how one should design waveforms in an adaptive fashion (cognitive radar) to extract maximal information from an imaged scene Waveform adaptation, sensor scheduling and waveform library design have all been approached from classical statistical signal processing perspectives We ask: • Can information theory provide bounds on the performance of closed loop information gathering systems such as cognitive radar?
• •
• •
Proposed a new information theoretic framework for obtaining fundamental bounds on the distortion in the radar scene reconstruction for closed loop adaptive waveform scheduling systems Future goals: • demonstrating the utility of this framework in tangible channels which accurately model radar situations of interest • tightening the theoretical results P. Setlur, N. Devroye, ``Waveform Scheduling via Directed Information in Cogntiive Radar,’’ IEEE SSP workshop, August 2012. P. Setlur, N. Devroye, ``Adaptive waveform scheduling in radar: an information theoretic approach’’, SPIE, April 2012.
Stefano Rini, Alex Dytso, Daniela Tuninetti, Natasha Devroye (ECE) NSF CCF, CIF Small Award 1017436: Fundamental Limits of Layered Wireless Networks
Problem Statement and Motivation • • •
• •
Key Achievements and Future Goals
Technical Approach • •
We first consider a symmetric Gaussian interference channel with a cognitive relay to reduce the complexity We obtain general inner and outer bounds which we are able to tighten for certain classes of channels such as the linear high SNR deterministic channel model
Cognition is a rapidly emerging new paradigm in wireless communication whereby a node changes its communication scheme to efficiently share the spectrum with other users in the network One way of modeling cognition is through non-causal message knowledge at certain nodes in a networks The interference channel with a cognitive relay consists of a two user interference channel where a third node, a cognitive relay knows the messages of both source nodes and aids in their transmission This channel generalizes numerous multi-user information theoretic channels including the interference channel, broadcast channel and cognitive interference channel We seek the capacity region of this channel to characterize its fundamental limits
• • • • • •
We have characterized the capacity region of the linear high SNR deterministic and symmetric channel model for many, but not yet all subsets of parameters We have characterized the capacity in the strong interference regime We will address these remaining cases before using the intuition gained to determine capacity to within a constant gap for the Gaussian channel S. Rini, D. Tuninetti, N. Devroye ``Capacity to within 3 bits for a class of interference channels with a cognitive relay,’’ ISIT 2011. S. Rini, D. Tuninetti, N. Devroye ``The capacity of an interference channel with a cognitive relay in strong interference,’’ ISIT 2011. A. Dytso, S. Rini, D. Tuninetti, N. Devroye ``On the capacity region of the symmetric, high SNR deterministic interference channel with a cognitive relay,’’’ ICC 2012.
Natasha Devroye, Daniela Tuninetti (ECE) NSF CCF, CIF Small Award 1017436: Fundamental Limits of Layered Wireless Networks
Problem Statement and Motivation • • •
Key Achievements and Future Goals
Technical Approach • •
We take an information theoretic approach to derive both inner and outer bounds to the capacity of such layered wireless networks We consider both centralized and distributed layered networks
Inefficiencies in spectrum usage have led to a interest in alternative secondary spectrum licensing paradigms The underlay secondary spectrum licensing paradigm allows for secondary users to simultaneously access the spectrum licensed to the primary users as long as they do not ``disrupt’’ the primary users We seek to determine the fundamental limits of layered secondary networks which share the spectrum with primary users under the constraints that: • Lower layers remain oblivious to higher layers (seamless layering, backwards compatibility, incentives for primary users) • Higher layers are more ``intelligent’’ and may thus opportunistically access the network and exploit added knowledge such as codebook knowledge
•
•
• •
Our proposed opportunistic interference cancelation scheme and rates has won the Best Paper Award at CROWNCOM 2011 (N. Devroye, P. Popovski `Receiver-side Opportunism in Cognitive Networks,’’ CROWNCOM, June 2011. A. Dytso, N. Devroye, D. Tuninetti, ``The sum-capacity of the symmetric linear deterministic complete K-user Z-interference channel,’’ Allerton 2012. D. Maamari, N. Dvroye and D. Tuninetti, ``The Sum-Capacity of the Linear Deterministic Three-User Cognitive Interference Channel’, ISIT 2012. Future goals: extensions to Gaussian noise and oblivionincorporating outer bounds
Shantanu Dutt, ECE Primary Grant Support: National Science Foundation Partitioning
Floorplanning
Placement
Problem Statement and Motivation
Routing Simulation
Incr. Place
VLSI CAD Flow:
•
Current and future very deep submicron chips are so complex and minute that they need “corrections” or re-optimizations in small parts after initial design & simul.
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Need to keep the correct parts of the chip as intact as possible – good resource usage, time-to-market req.
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Need incremental CAD algorithms that re-do the “incorrect” parts fast and w/o significant effect on the correct parts
•
This project focuses on such incremental algorithms at the physical CAD or layout level of chip design – placement & routing
e.g., for timing closure
Key Achievements and Future Goals
Technical Approach •
•
Use of a constraint-satisfying depth-first search (DFS) process that explores the design space for the incremental changes to: • Optimize them (e.g., power, critical path, signal integrity) • Subject to not deteriorating metrics of the larger unchanged chip beyond pre-set bounds (e.g., <= 10% increase in wirelength)
Use of a new network-flow based methodology to explore the design space in a more continuous manner (as opposed to discrete in DFS) for faster solutions: • Some approximations involved for discrete -> continuous optimization mapping
•
Incremental routing for FPGAs: • optimal DFS algorithm wrt # of tracks– if a solution exists will find it; 13 times faster than competitor VPR
•
Incremental routing for VLSI ASICs: • 98% success rate in completing routes – up to 9-12 times fewer failures than Std and R&R routers
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Timing-driven incremental routing for VLSI ASICs: • 94% succ rate; 5 times fewer timing violations
•
Incremental placement for VLSI ASICs: • Prel results: applied to timing closure – 10% improv
•
Future Work: (1) Apply to timing, power closure via logic & circuit re-synthesis at the physical level + re-placement & re-routing; (2) Integration of incremental routing & placement
Ashfaq Khokhar and Rashid Ansari Multimedia Systems Lab. (http://multimedia.ece.uic.edu) Primary Grant Support: National Science Foundation
Problem Statement and Motivation • •
•
Key Achievements and Future Goals
Technical Approach • •
• •
Develop efficient watermarking techniques that can imperceptibly embed information in the media Embedding capacity (#of bits embedded) of the proposed techniques should be large and embedded information should withstand different types of adversary attacks including re-sampling, compression, noise, desynchronization, etc. – exploit temporal and spatial correlation in the multimedia data. Develop detection algorithms that can detect the embedded information in the face of modifications and other adversary attacks. Develop distributed protocols based on trust metrics to recover modified contents
Emergence of peer to peer networks and increased interest in online sharing poses challenges for preserving and protecting online digital repositories. Existing efforts are mostly focused on text data. Research challenges are amplified when the contents are multimedia – just re-sampling of voice or image data, which is difficult to detect, compromises the authentication and validation. Developing multimedia asset management tools and distributed protocols that embed signatures, evaluate authentication, and help perform recovery using copies at peer nodes, if contents have been compromised.
•
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• •
Developed novel watermarking techniques that embed information in selective frequency subbands. The embedded information is 10-15 times more than existing techniques and can withstand adversary attacks. Developed an Independent Component Analysis based detector that can detect embedded information in the presence of extreme noise (less than 1% error probability even in the presence of 80% noise). Developing a comprehensive digital asset management system using data hiding for fingerprinting and authentication. Developing a suite of distributed protocols for content validation and recovery in case of compromised data.
Gyungho Lee, ECE Primary Grant Support: NSF
Problem Statement and Motivation
Key Achievements and Future Goals
Technical Approach instruction-level program behavior description with execution path
•
Achievement • program counter encoding for low cost control flow validation • augmented branch predictor for complete control flow validation
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Future • Data Flow Validation • Industrial Control System - SCADA • mobile devices – 4G cell phone environment
Dan Schonfeld, ECE; Wei Qu, ECE; Nidhal Bouaynaya, ECE Primary Grant Support: Motorola, Inc., NeoMagic Corp.
Problem Statement and Motivation • • • • • •
Key Achievements and Future Goals
Technical Approach • • •
• • •
Particle Filter Motion Proposal Detection Proposal
x11 x
2 2
x
.. .
.. . x2m
m 1
x 1 1
z
z z12 . ..
xt1 xt2
...
..
. xtm
1 t
1 2
z
zt2 . ..
z22 . .
.
z1m
Magnetic-Intertia Model Interactive Distributed Model Mixture Hidden Markov Model
... ...
x12 2 1
z2m
Video Surveillance (Activity Monitoring) Video Communications (Virtual Background) Video Enhancement (Handheld Camera Quality) Video Animation (Virtual Conference Room) Video Steroegraphy (3D from a Single Camera) Video Retrieval (Visual Search Engine)
ztm
• • • • • • • •
Real-Time (No Offline Processing Required) Very Fast (Few Particles Required) Low-Power (Embedded Processors) Complete Occlusion (Hidden Targets) Multiple Camera Tracking (Information Fusion) Video Auto-Focus (Fixed Lens Camera) Video Stabilization (Handheld & Vehicle Vibrations) Randomly Perturbed Active Surfaces (Robust Contour)
Primary Investigator: Hulya Seferoglu
Practical Network Control (NC) for Wireless Networks
Technical Approach • Goal: Develop a new theory for optimal network control that takes into account practical constraints. • Approach: Consider practical issues that arise at multiple levels of the system hierarchy including; • Device-level issues: Investigating the impact of device limitations, • Protocol-level considerations: Investigating the interaction of between legacy protocols and the optimal control framework. • Network-level migration: Developing control algorithms for a network with a mix of controllable and uncontrollable nodes. • Test-bed implementation: Implementing our control algorithms using commodity off-the-shelf devices.
Problem Statement and Motivation • Problem: • Growth in mobile and media rich applications Increasing demand for wireless bandwidth • Dramatic increase in demand poses a challenge for current wireless networks • Existing approaches: • Significant research on the theory of network control • Deployment of theory is rather limited due to the gap between theory and practice • Motivation: • New network control mechanisms are needed • Better use of scarce wireless resources • Taking into account practical constraints
Key Achievements and Future Goals • The PI has published several conference and journal papers in the broader area. • The PI has submitted a proposal about this project to NSF. The proposal submission is currently under review.
Daniela Tuninetti, Natasha Devroye, Stefano Rini, ECE Primary Grant Support: Dr. Tuninetti’s NSF CAREER grant.
Problem Statement and Motivation
+ 2. Bits received at the same power as the noise are `erased’. 3. Approximate the real sum with a bit-wise sum
•
In multi-terminal additive Gaussian noise networks two factors determine the network performance: the noise and user interference.
•
While we understand how to operate networks in the noise limited regime (i.e., the interference power is comparable to the noise power), we still do not have a clear grasp on how to operate networks in the interference limited regime.
•
A promising tool towards this goal is to approximate the (probabilistic) Gaussian network with a deterministic one in which the effect of the noise is neglected and the interference among users is deterministic.
1. Translate the received powers in bit levels
XOR The noise `erases’ some bits. The remaining bits interfere with each other.
Key Achievements and Future Goals
Technical Approach •
The signals and the noise are approximated with binary vectors whose length equals the number of bits that we can be send over a link.
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We determined the capacity region of the deterministic two-user cognitive interference network.
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All the bits received below the noise level are considered erased (i.e., unreliable).
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This result provided some inside on the the capacity of a general Gaussian cognitive network.
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Real-value summations are approximated by binary XOR operations.
•
Our future goal is to determine the capacity of Gaussian cognitive interference channels within a constant gap.
•
We will extend this framework to more general cooperative networks.
In this simplified framework, the effect of the noise and of the interference becomes deterministic. Determining the optimal network performance is expected to be easier for the deterministic network than for the original probabilistic Gaussian network.
Oliver Yu, Department of Electrical and Computer Engineering Primary Grant Support: DOE, NSF On-demand Lightpath (10 Gbps) Cluster All-optical LAN
Cluster Chicago StarLight
Amsterdam NetherLight
PIN All-optical MAN UIC
Cluster
PIN
Lambda Grid reserves lightpaths or lambdas of light (10 Gbps transport capacity) among a distributed collection of data, computing, visualization and instrumentation resources that are integrated to provide collaborative capability to end users.
•
To support a Multi-domain Lambda Grid with on-demand lightpath provisioning over multiple optical network domains with heterogeneous control planes.
•
To support e a Multi-purpose Lambda Grid for multidisciplinary collaborative applications.
PIN University of Amsterdam
ISON
•
All-optical LAN ISON
ISON
Problem Statement and Motivation
Chicago OMNInet
Key Achievements and Future Goals
Technical Approach •
•
Photonic Inter-domain Negotiator (PIN) is developed to support the Multi-domain Lambda Grid. It provides an open secure inter-domain control plane to interoperate multiple optical network domains with non-compatible signaling and routing functions. Integrated Services Optical Network (ISON) is developed to support the Multi-purpose Lambda Grid. It provides multiple traffic transport services: Gigabit-rate stream (single lambda per application); Kilo/Megabit-rate stream (multiple applications per lambda); Tera/Petabit-rate stream (multiple lambdas per application); and variable bit rate bursty traffic.
• • • •
• •
Publication O. Yu, “Intercarrier Interdomain Control Plane for Global Optical Networks,” in Proc. IEEE ICC, June 2004. O. Yu, T. DeFanti, “Collaborative User-centric Lambda-Grid over Wavelength-Routed Network,” in Proc. IEEE/ASM SC 2004, Nov. 2004. Three journal papers has been submitted to IEEE/OSA Journal of Lightwave Technology. Demonstration Through collaboration with University of Amsterdam, on-demand lightpath provisioning was demonstrated over Lambda Grid between Chicago & Amsterdam in SC 2003, November 2003. Future Goals Extend multi-domain and multi-purpose Lambda Grid with photonic multicast capability by splitting incoming light into multiple outputs. Demonstrate the new prototype in iGrid 2005 symposium at San Diego.
Zhichun Zhu, ECE Primary Grant Support: NSF
Problem Statement and Motivation •
Multi-core and many-core processors have increasing demands on memory capacity and bandwidth
•
Conventional memory systems are heading to a scalability wall • Memory power consumption becomes a significant part of system power profile • Memory thermal emergency becomes an important design consideration
•
New memory technologies emerge to address the memory scalability issue; but there lack architectural supports for them
Key Achievements and Future Goals
Technical Approach •
Universal memory architecture to support diverse memory modules
•
Thread-aware memory scheduling to improve memory performance
•
Memory management schemes for heterogeneous memory systems
•
Coordinated memory thermal management schemes
•
Processor-memory cooperation to optimize system performance and power-efficiency
•
Decoupled memory organization to optimize memory power-efficiency and performance
•
Memory thermal models and simulators
P.I. Igor Paprotny Funding: new faculty startup, Intel, DOE
Problem Statement and Motivation • • •
Airborne particulate matter (PM) is harmful to our health In particular fine PM smaller than 2.5 µm in diameter (PM2.5) Includes: • Diesel exhaust • Tobacco smoke • Bio-aerosols
• •
Current instruments are too big and expensive to be portable Personal PM2.5 sensor does not exist
Key Achievements and Future Goals
Technical Approach • • •
•
Use MEMS techniques to create air-microfluidic lab-on-a-chip that measures airborne PM by direct mass deposition Inertial separation (virtual impaction) is used to separate PM2.5 from the rest of the airstream. Thermophoretic precipitation is used to deposit the separated PM2.5 on top of a mass-sensitive film-bulk acoustic resonator (FBAR) The rate of the frequency shift in the FBAR corresponds to the PM2.5 concentration.
• • • •
Demonstrated a microfabricated PM2.5 direct-mass sensor • 5 cm x 2.5 cm x 1 cm in size Sensitivity comparable to large instruments • 1-2 µg/m3 PM2.5 concentration Form factor enables integration into a regular cellphone Future goals: • Improve sensitivity • Measure particle-size distribution • Chemical speciation
P.I. Igor Paprotny Funding: Department of Health and Human Services
Problem Statement and Motivation • • • •
Key Achievements and Future Goals
Technical Approach • • • •
A flat surface placed in a mine environment collects deposited dust Incident light at several wave-lengths is reflected from the deposited layer, and is collected by a photo-detector Microfabricated mass sensors and humidity sensors helps to determine the true explosibility of the deposited layers Connects to a communication backbone to automate the operation of the rock dusting equipment
Excessive build-up of coal dust in underground mines leads to explosion risk Rock-dusting (dispensing of inert lime-stone dust) is used to mitigate the explosion risk • Increasing total incombustible content (TIC) Currently manual sampling of dust in mines to determine TIC and control rock dusting A low-cost reliable automated method is needed
• • •
Verified the viability of using multi-wavelength optical method to detected the layers of deposited dust Created preliminary sensor prototype Future goals: • Determine the dependence of the optical method on humidity content and particle size, as well as the layer thickness • Create a MEMS mass and humidity sensor • Integrate with a communication backbone in the underground mine
Mahshid Amirabadi, Department of Electrical and Computer Engineering
Problem Statement and Motivation •
•
•
Key Achievements and Future Goals
Technical Approach •
ac-link universal power converters are new class of power converters with numerous advantages over the existing technologies: • The input and output of these converters may be dc, single phase ac, or multiphase ac. They can be employed in a variety of applications including, but not limited to, photovoltaic power generation and wind power generation systems. • Link current and voltage are alternating and their frequency can be high. This results in compact link and filter elements. • They do not need dc electrolytic capacitors or low frequency transformers. • ac-link Universal power converters provide soft switching. Therefore, the switching losses are negligible and the link frequency may be increased further.
Power Electronics is an integral part of many systems including, but not limited to, renewable energy systems and electric and hybrid electric vehicles. The existing power electronic circuits have some limitations • They are usually bulky. • Their reliability is low and they have a short lifetime. For example, the lifetime of the PV inverters is 5-10 years whereas the life time of a PV module is 25 years. Therefore, PV inverters need to be replaced 2 or 3 times within the lifetime of a PV module. • The low reliability of power converters adds cost to the system. For the long-term success of renewable energy sector we have to increase the reliability of power converters, decrease their size/weight and reduce their cost.
• • • •
ac-link universal power converters are much more compact compared to the existing technologies. They have higher reliability. They are less expensive. Sparse and ultra-sparse ac-link universal power converters have the same principles of the operation but they require fewer switches: • They further decrease the size. • They dramatically increase the reliability. • They are less expensive than the ac-link universal power converters.
Sudip K. Mazumder, ECE Primary Grant Support: NSF, DOE (SECA and I&I), PNNL, CEC, NASA, Ceramatec, Airforce (award pending), TI, Altera
Problem Statement and Motivation •
To achieve reliable interactive power-electronics networks
•
To design and develop power-management electronics for residential and vehicular applications of renewable/alternate energy sources (e.g., fuel and photovoltaic cells)
•
To achieve higher power density and realize systems on chip
Key Achievements and Future Goals
Technical Approach •
Stability and Stabilization of Power-Electronics Networks: a) Global stability analysis of stochastic and functional hybrid system b) Stabilization using wireless networked control
•
Optimal Fuel Cell based Stationary and Vehicular Energy Systems a) Resolving interactions among energy source (such as fuel cells), power electronics, and balance of plant. b) Fuel-cell power-electronics inverter design that simultaneously meet criteria of cost, durability, and energy efficiency
•
Robust and efficient power devices and smart power ASIC a) High-speed, EMI immune, wide-bandgap power devices b) Integration of low- and high-voltage electronics on the same chip
•
First, wireless distributed control dc/dc and multiphase converters and three-phase induction motor control
•
First, zero-ripple, multilevel, energy-efficient fuel cell inverter
•
First, photonically-triggered power transistor design for power electronics
•
First, nonlinear VRM controller for next-generation Pentium processors
•
Comprehensive solid-oxide-fuel-cell (SOFC) spatio-temporal system model
Sudip K. Mazumder, Professor, Electrical and Computer Engineering Department Director, Laboratory for Energy and Switching-Electronics Systems Funding Agencies: NSF, ONR, DOE, AFRL, GeneSiC Semiconductor, APEI
Hybrid SiC optical power device
Optically-switched highfrequency and high-voltage power converter
Problem Statement and Motivation •
To realize a high-gain, high-voltage, and high-temperature opticallyswitched power transistor, which is triggered in a non-latched manner using low power monochromatic photonic source by monolithically integrating an optically-controlled transistor with a high-voltage SiC field-effect transistor.
•
The scalable device technology can have radical impact for highvoltage and ultra-high-frequency power-electronics/power systems including solar/wind/fuel-cell inverters, energy storage systems, pulsed power, fault current limiting, fly-by-light systems, solid-state transformer, electromagnetic-interference-immune systems.
Key Achievements and Future Goals
Technical Approach •
•
GaAs-based optically-controlled high-gain superjunction lateral triggering device to enable non-latched and low-cost long-wavelength triggering SiC based high-voltage and high-temperature vertical metal-oxidesemiconductor-field-effect transistor (MOSFET) for power switching at high frequency and high voltage
•
Optoelectronic integration of the hybrid SiC MOSFET and GaAs based optical triggering device to yield hybrid SiC optical power device
•
Power converter design and fabrication using the hybrid SiC optical power device and switching characterization of the power converter under high-frequency and high-voltage operation.
• • • • •
World’s first 0.25 MHz wide-bandgap device based opticallyswitched dc/dc converter 6 NSF, ONR, DOE, and AFRL grants 2 U.S. patents received and 1 patent pending 2 journal papers in IEEE Transactions on Power Electronics with an impact factor > 5 Future work involves a) optically controlled very high voltage (> 15 kV) SiC bipolar transistor; b) control of a power-electronic system at device level by dynamic intensity and/or wavelength modulation of the optical power device.
P.L.E. Uslenghi (P.I.), S. Dutt, D. Erricolo, H-.Y. D. Yang, ECE in collaboration with Clemson University, Houston University, Ohio State University, University of Illinois at Urbana-Champaign, University of Michigan Primary Grant Support: AFOSR
Problem Statement and Motivation
High Power EM fields
E
Puls er
•
Understand and predict the effects of the new electromagnetic threat represented by high power microwave (HPM) and ultrawide band (UWB) pulses on digital electronic systems found inside fixed or moving platforms.
•
Develop recommendations for performing field tests/measurements
H
External EM Source (Impulse Radiating Antenna)
Illuminated target
Key Achievements and Future Goals
Technical Approach •
Apply electromagnetic topology to predict the effects of HPM/UWB aggressor signals
•
Fast computer codes are under development at UH, UIUC, UM and OSU.
•
Apply recently developed fast and accurate computer simulation tools.
•
Topology studies are underway at CU. Analysis of devices and of processor faults are being conducted at CU and UIC.
•
Further extend the capabilities of the computer simulation tools to obtain a better understanding of the overall problem.
•
Validation tests for codes are being developed at CU, OSU, and UIC.
Investigators: M. Dutta, ECE, and M. Stroscio, ECE and BioE
Problem Statement and Motivation
Bare QDs
FRET
• Organic-inorganic hybrid structures enable integration of useful organic and inorganic characteristics for novel optoelectronic applications. • The time required for resonant energy transfer in the composite of inorganic quantum dots (QDs) and photosystem I (PS-I) has not been determined previously. Transfer time ~ 6 ps).
Colloidal Quantum Dots and Photosystem-I Composite
Technical Approach • Synthesis of the composite of inorganic CdSe QDs and organic PS-I, hexahistadine-tagged PS-I from Chalamydomonas reinhardtii - green unicellular algea • Experimental measurement of the energy transfer between QDs and PS-I • Investigation of structural, optical and transport properties by means of photoluminescence, time-resolved photoluminescence, absorption, capacitance-voltage and I-V measurements
Key Achievements and Future Goals • Observed energy transfer from CdSe QDs to PS-I by optical and electrical measurements. • Photoluminescence data and absorption data show that the energy of excited carriers of CdSe QDs to PS-I by processes that include fluorescent resonant energy transfer (FRET) between the inorganic and organic components of the system. • I-V measurement data are sensitive to incident light in the composite CdSe QDs/PS-I material.
Investigators: ; M. Dutta, ECE, and M. Stroscio, ECE and BioE
Problem Statement and Motivation • Design, fabrication, characterization of QD-based nanosensors on a variety of platforms • For underlying concepts see group’s paper on “Applications of Colloidal Quantum Dots,” Microelectronics Journal, 40, 644-649 (2009).
Technical Approach • Design of quantum-dot (QD) based nanosensors
Key Achievements and Future Goals • Numerous demonstration of nanosensors based on beacon like structures
• Fabricating quantum-dot (QD) ensembles • Modeling electrical and optical properties including robustness and sensitivity to QD-QD separation
• Numerous nanosensors demonstarted for a variety of QD systems
• QD blinking modeled and observed • Experimental characterization of integrated structures • Multi-analyte detection
• Ultimate goal is realization of multi-analyte detectors on a single platform
P.I. Igor Paprotny Funding: new faculty startup
Problem Statement and Motivation • • • •
200 mm •
Key Achievements and Future Goals
Technical Approach • • •
• •
Use MEMS techniques to create robotic chassis several micrometers in size A stress-engineering post processing solution adds precisely controlled curvature to planar silicon structures Power is provided externally through a set of underlying interdigitated electrodes to the propulsion component, which is a scratch drive actuator (electrostatic inchworm) Patterned stress-engineering layer defines the out-of-plane deflection of the steering arms Difference in deflection results in different control voltage, which can be used to independently control several microrobots
New, largely unexplored area of robotics Difficult to achieve due to component scaling Microelectromechanical systems (MEMS) Components difficult to implement at the microscale: • On-board power • Sensing • On-board control Many application opportunities, such as in: • Medicine, • Manufacturing • Information security
• • • •
Demonstrated independent control of several (four) MEMS microrobots Controlled self-assembly of microscale structures Developed a new stress-engineering process to design the robots that does not require a photo lithography stage Future goals: • Develop designs and algorithms that allow for simultaneous control of large numbers of microrobots • Create new microrobotic systems that operate in liquids • Use 2-photon stereolithography to create new types of microrobotic systems
Mitra Dutta, ECE and Michael Stroscio, ECE & BioE Primary Grant Support: ARO, AFOSR (a) 0 1 2
-4
Fluorescence
-3 LUMO
3 4 5 6 7
HOMO
•
Organic-inorganic hybrid structures enable integration of useful organic and inorganic characteristics for novel applications such as solar cell, chemical sensors, and fluorescent biotags.
•
Energy transfer in the composite of inorganic quantum dots (QDs) and photosystem I (PS-I) is not understood although it is very important and well studied for photosynthesis.
0 +1
+- +-
+2 CdSe QDs
QDs
-2 -1
En1 Ec hv Ev Eh1
8
Problem Statement and Motivation
NEH(V)
Evac(eV)
+3
PS-I
QDs+PS1
Glass
Glass
Key Achievements and Future Goals
Technical Approach •
Synthesis of the composite of inorganic CdSe QDs and organic PS-I
•
Observed energy transfer from CdSe QDs to PS-I by optical and electrical measurements.
•
Experimental measurement of the energy transfer between QDs and PS-I
•
Photoluminescence data and absorption data show that the energy of excited carriers of CdSe QDs to PS-I by means of radiative emission, FRET, and electron/hole transfer between the inorganic-organic system.
•
I-V measurement data are sensitive to incident light in the composite CdSe QDs/PS-I material.
•
Further studies continue to identify each energy transfer method.
•
Investigation of structural, optical and transport properties by means of photoluminescence, time-resolved photoluminescence, absorption, capacitance-voltage and current-voltage measurements
Investigators: ; M. Dutta, ECE M. Stroscio, ECE and BioE
Problem Statement and Motivation Example of ZnO Nanowires
• Design, fabrication, and characterization of quantum-wire based optoelectronic devices and structures including those incorporating conductive polymers • Design, fabrication, and characterization of quantum-wire based piezoelectric devices and structures for energy harvesting
Technical Approach • Growth of quantum wires
Key Achievements and Future Goals • Numerous simulations of electrical, optical and piezoelectric properties of quantum-wire structures
• Fabrication of quantum-wire based devices • Modeling electrical and optical properties including robustness of quantum-wire-based devices
• Numerous simulations and predictions for a variety of quantum-wire—conductive-polymer structures and piezoelectric structures
• Experimental characterization of integrated structures quantum-wire-based structures
• Demonstrated polarization-dependent light inteactions with arrays of quantum wires • Strong Enhancement of Near-BandEdge PLof ZnO Nanowires
M. Dutta, ECE; M. Stroscio,ECE and BioE Primary Grant Support: ARO, NSF, AFOSR, SRC, DARPA
Problem Statement and Motivation Au wire
CdS
CdSe-ZnS
•
Future electronic and optoelectronic systems must be integrated on the terascale and beyond
•
This research effort explores the use of biomolecules as molecular interconnects for such terascale systems
CdSe-ZnS-GGGC
Key Achievements and Future Goals
Technical Approach •
Synthesis of semiconductor nanostructures
•
Chemical self-assembly of semiconductor nanostructures
•
Modeling electrical, optical and mechanical properties of ensembles of nanostructures
•
Experimental characterization of massively integrated networks of semiconductor nanostructures
•
Numerous manmade semiconducting nanostructures have been synthesized
•
Integrated semiconductor quantum dots have been assembled chemically in the Nanoengineering Research Laboratory at UIC
•
Interactions between semiconductor nanostructures and molecular wires have been modeled for a wide variety of systems
•
Ultimate goal is massive integration of semiconductor nanostructures in functional electronic and optoelectronic networks
Mitra Dutta, ECE. Primary Grant Support: NASA Ames Research Center
Problem Statement and Motivation •
Annealing at specific conditions and environment would refresh the Tin Oxide nanowire used in gas sensing applications.
•
Minimization of defects in nanowires which determine the electrical and optical properties for high performance applications.
Key Achievements and Future Goals
Technical Approach •
Synthesis of Tin Oxide nanowires using a special carbothermal reduction process.
•
Identifying various inherent structural defects in nanowires and understanding their role in modifying the electronic and optical properties using various experimental characterization techniques.
•
Obtain a specific Annealing condition which would serve to minimize the defects as well pre-charge/refresh the nanowires for future gas sensing applications.
•
Nanowires of various diameters have been synthesized in large scale.
•
Intrinsic defect levels/states/traps have been identified and minimized by annealing in oxygen and nitrogen under specific conditions. Luminescence and structural properties of the wires have improved/changed by a significant extent post annealing.
•
Specific annealing condition used for refreshing nanowires has been obtained.
•
Ultimate goal is massive integration of tin oxide nanowires for gas sensing and nuclear radiation detection.
Mitra Dutta, ECE Primary Grant Support: Intelligent Expitaxy Technology and MDA
[011] [011] aAs 1mm G
GaAs 150nm
•
Robust low cost Infrared photodetectors as well as those with room or near room temperature operation
•
Quantum well infrared photodetectors (QWIPs) due to the well developed mature GaAs technology
•
High-pass filter for the photocurrent which blocks the tunneling dark current
[100]
s 0.79A l0.21Ga 5nm A 0.9As In0.1Ga 3.5nm a0.79As Al0.21G 50nm
Quantum Well Infrared Photodectetor (QWIP) with a energy filter between base and collector
Problem Statement and Motivation
d grade filter 40nm a0.79As Al0.21G
Key Achievements and Future Goals
Technical Approach •
InxGa1-xAs/AlyGa1-yAs multi quantum wells, three terminal structure grown by molecular beam epitaxy
•
The atomic resolution images and x-ray diffraction patterns verified a lattice matched and band-gap engineered device structure of IHET.
•
Modeling of electrical properties based on its composition and doping
•
Photoluminescence data indicated the composition and a deep energy level in hot electron filter
•
Investigation of structural, optical and transport properties by means of transmission electron microscopy, x-ray diffraction, Photoluminescence, Raman spectroscopy, current-voltage measurement
•
Current-voltage data showed high-pass filter blocks the tunneling dark current, with resulting satisfactory detectivity
•
Optimization of the composition, thickness, and doping of high-pass filter
Mitra Dutta, ECE and Michael A. Stroscio, ECE and BioE Primary Grant Support: ARO AFOSR
Problem Statement and Motivation •
Semiconductor nanocrystals functionalized with conductive polymers promote efficient charge transfer
•
Low cost, light weight and tunable conductivities
•
Explore the application of nanocomposite heterostructures in novel electronic and optoelectronic devices
Key Achievements and Future Goals
Technical Approach •
Fabrication of nanocomposite heterostructures incorporating semiconductor quantum dots and inorganic polymers
•
Different types of nanocomposite heterostructures have been synthesized
•
Numerical modeling of the electrical properties
•
Electrical and optical properties have been studied with modeling and experimental methods
•
Experimental characterization with optical and electrical measurements
•
Developing high efficiency photodetectors and solar cells
Investigators: Banani Sen, ECE, Mitra Dutta, ECE, Physics, Michael Stroscio, ECE, BioE, Physics Alex Yarin, MIE, Suman Sinha-Ray, MIE
Problem Statement and Motivation
V
•
Piezoelectric energy harvesting is necessary to meet today’s energy requirement.
•
ZnO nanofibers have drawn much attention because of its promising material characteristics.
•
Bulk production of substrate free nanofibers are needed for various application, viz. power shirts.
L L ± L (a) TEM image of ZnO nanofiber deposited by electrospinning. (b) Schematic representation of energy harvesting measurement setup.
Key Achievements and Future Goals
Technical Approach •
Synthesis of ZnO nanofibers by electrospinning followed by annealing in oxygen ambient.
•
TEM image shows single crystalline stoichiometric ZnO nanofibers deposited by electrospinning.
•
Investigation of morphological, optical and material properties by means of Transmission electron microscopy, Photoluminescence and Raman spectroscopy.
•
Photoluminescence spectrum shows UV peak (near band), Vis peak ( antisite defects and interstitial oxygen).
•
•
Synthesis of ZnO nanofiber and PVDF polymer composite by electrospinning for energy harvesting.
Raman scattering- E2 (high), quasi LO and TO modes of mixed A1 and E1 symmetry.
• •
Piezoelectric voltage measurement on application of mechanical strain.
Preliminary electrical measurement results indicate the composite to be promising for energy harvesting. Further systematic study will be continued to evaluate the power density from this piezoelectric composite.
Investigators: Mohsen Purahmed, Mitra Dutta, ECE Department of Electrical Engineering, University of Illinois at Chicago
Problem Statement and Motivation •
ZnO NWs are one of the promising candidates for future nanostructure devices such as short-wavelength semiconductor lasers, light-emitting diodes and energy harvesting devices.
•
ZnO NWs have a weak near-band-emission (NBE), numerous studies have been done to enhance the NBE and photoluminescence efficiency of ZnO Nanowires (NWs).
ZnO nanowires (NWs) grown by PVD method
Key Achievements and Future Goals
Technical Approach •
Growth of ZnO NWs by PVD method
•
Optical characterization of ZnO NWs
•
Enhancement of near-band-emission (NBE )of ZnO
•
Photoluminescence (PL) of ZnO nanowires coated with the metallic nano particles deposited by rf-magnetron sputtering .
•
Very strong enhancement of ultraviolet emission is observed after coating with metallic nanoparticles and Ar plasma treatment.
•
Future goals include studying the waveguiding and lasing effects in these ZnO NWs and making a nano laser with a low threshold lasing power.
Hyeson Jung and Mitra Dutta Department of Electrical and Computer Engineering
Current Density (mA/cm2)
0
Problem Statement and Motivation
68SE1-68AE10
-5 -10 -15
Voc : 0.79V Jsc : 22.96 mA Vmp : 0.62 V Jmp : 19.62 mA FF : 67.06% eff :12.16 %
•
Current commercial solar cells - single/poly crystalline silicon
•
Recent crystalline silicon wafer prices increases make second generation cells more attractive
•
The Second-generation cells – thin film of amorphous Si, CdTe, and CIGS can be competitive
•
Energy band gap of CdTe is 1.5 eV, considered optimal band gap for solar cells
•
CdTe solar cell higher efficiency than a-Si
-20 -25 -30 0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
Voltage (V)
Key Achievements and Future Goals
Technical Approach •
Fabrication of CdTe thin film solar cell: CdTe, CdS thin film deposition by means of e-beam followed by cell fabrication
•
Development of alternative post-treatment, and optimization of the treatment condition
•
Investigation of structural, optical and transport properties by means of Photoluminescence, X-ray spectroscopy, absorption measurement, Scanning Electron Microscopy, Atomic Force Microscope, and current-voltage measurement
•
CdTe solar cells were fabricated and tested; the CdTe was grown by e-beam evaporation or magnetron sputtering, followed by post treatment.
•
Alternative post treatment system was developed.
•
12 % efficiency achieved with first efforts.
•
Incorporating nanostructures we hope to achieve higher efficiency
Hyeson Jung, Michael Stroscio, Mitra Dutta Department of Electrical and Computer Engineering
(111) 110
En1 ,h1
2 212 2 212 Eg * * 2me a 2 2mh a 2
Problem Statement and Motivation •
To explore materials for tandem solar cells, PbSe nanowires were investigated. By adjusting diameter of the wires, bandgap can be engineered. This is one of advantages of nanotechnology.
•
Nanowires of PbSe are of enhanced interest due to their special properties where the relatively large Bohr excitonic radius and small effective masses lead to strong electron and hole confinement in PbSe nanowires.
PbSe
EC En1 EF EV Eh1
Depletion region, W
Oxidized PbSe surface
Key Achievements and Future Goals
Technical Approach •
•
•
Growth of quality PbSe nanowires which are contamination free, compatible with device processing, less expensive and simple by using RF sputter deposition. The optical properties of the wires were characterized by absorption and photoluminescence.
Investigate possibility of achieving nanowire behavior in PbSe larger wires that are grown by sputter deposition due to the effect of surface field and a strong depletion layer.
•
PbSe nanowires grown by magnetron sputtering
•
Though of large size wires showed a large blue shift demonstrating quantum confining
•
Attributed to Fermi level and strong band pinning, large band bending and a wide depletion layer
•
We have demonstrated that effective diameter of the nanowires are adjustable for different band gap materials.
•
Development of solar cells using these PbSe nanowires in the near future
Ayan Kar and Mitra Dutta, ECE Primary Grant Support: DoE
Problem Statement and Motivation •
Long term need for an inexpensive sensor for the detection of special nuclear materials.
•
Ideally sensors which are small, with minimal circuit complexity, and non-cryogenic cooling and requiring small manufacturing costs would provide ideal solutions to this problem.
•
Tin oxide (SnO2) nanowires have demonstrated to have excellent sensing performance which is comparable to or even surpasses the best thin film counterparts.
Key Achievements and Future Goals
Technical Approach •
Nanowire surface modification using annealing.
•
Fabrication of SnO2 nanowire Schottky diode sensors.
•
Expose the nanowire sensors to ionizing 20 Curies of Cesium-137 (137Cs) γ –radiation having an energy of 667 KeV.
•
Investigation of change in diode electrical properties on being exposed to radiation using current-voltage measurements. Change in nanowire structural properties using photoluminescence.
•
Large changes (~14.8 MΩ) in resistance in the forward bias region were observed after exposure to the 137Cs) γ –radiation.
•
A maximum sensitivity of 254% was obtained at a radiation dosage of 42,371 mR/hr.
•
A short sensor response time of 8 seconds with the permanent change in the nanowire resistance after the radiation is turned off.
•
Future possibility of stand-off remote detection of radioactive sources using a mm-wave (MMW) technique.
Investigators: ; M. Dutta, ECE and M. Stroscio, ECE and BioE
Problem Statement and Motivation Quantum Dots in MEH-PPV Polymer
Gold contacts
ITO
Glass
• Design, fabrication, characterization of QD-based photonabsorbing media embedded in conductive polymers for optoelectronic devices • For underlying concepts see group’s paper on “Applications of Colloidal Quantum Dots,” Microelectronics Journal, 40, 644-649 (2009).
Top view
MEH-PPV Polymer / CdSe Quantum Dot Composite
Technical Approach
Key Achievements and Future Goals
• Design of quantum-dot (QD) ensembles in conductive polymers
• Numerous simulations of electrical and optical properties including robustness and sensitivity to QD-QD separation
• Fabricating quantum-dot (QD) ensembles in conductive polymers
• Numerous simulations for a variety of QD—conductivepolymer systems
• Modeling electrical and optical properties including robustness and sensitivity to QD-QD separation
• Current sensing AFM measurements of I-V curves for a variety of QDs embedded in conducting polymers
• Experimental characterization of integrated structures
• Ultimate goal is realization of multi-wavelength photodetectors
• Multi-wavelength optoelectronics
Vitali Metlushko, Department of Electrical & Computer Engineering and Nanotechnology Core Facility (NCF) Primary Grant Support: NSF ECS grant # ECS-0202780, Antidot and Ring Arrays for Magnetic Storage Applications and NSF NIRT grant # DMR-0210519 : Formation and Properties of Spin-Polarized Quantum Dots in Magnetic Semiconductors by Controlled Variation of Magnetic Fields on the Nanoscale, B. Janko (P.I.), J. K. Furdyna (co-P.I.), M. Dobrowolska (co-P.I.), University of Notre Dame is leading organization, A. M. Chang (Purdue) and V. Metlushko, (UIC)
Problem Statement and Motivation Lorentz image of magnetic nanostructure.
The field of nanoelectronics is overwhelmingly dedicated to the exploitation of the behavior of electrons in electric fields. Materials employed are nearly always semiconductor-based, such as Si or GaAs, and other related dielectric and conducting materials. An emerging basis for nanoelectronic systems is that of magnetic materials. In the form of magnetic random access memories (MRAM), nanoscale magnetic structures offer fascinating opportunities for the development of low-power and nonvolatile memory elements.
SEM image of 700nm MRAM cells. UIC’s Nanoscale Core Facility
Key Achievements and Future Goals
Technical Approach In past few years, the interest in nano-magnetism has encreased rapidly because they offer potential application in MRAM. Modern fabrication techniques allow us to place the magnetic elements so close together that element-element interactions compete with singleelement energies and can lead to totally different switching dynamics. To visualize the magnetization reversal process in individual nanomagnets as well as in high-density arrays, Metlushko and his coauthors employed several different imaging techniques- magnetic force microscopy (MFM), scanning Hall microscopy, magneto-optical (MO) microscopy, SEMPA and Lorentz microscopy (LM).
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This project has led to collaboration with MSD, CNM and APS ANL, Katholieke Univesiteit Leuven, Belgium, University of Notre Dame, NIST, Universita` di Ferrara, Italy, Inter-University Micro-Electronics Center (IMEC), Belgium, Cornell University, McGill University and University of Alberta, Canada
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During the past 3 years this NSFsupported work resulted in 21 articles in refereed journals already published and 10 invited talks in the US, Europe and Japan.
Investigators: M. Stroscio, ECE and BioE; and M. Dutta, ECE 0 1
Evac
Al0.25Ga0.75N
CdSe Quantum Dot PDCTh Polymer
2 3 4 5 6 7 8 Al0.125Ga0.875N
PDCTh Polymer
Technical Approach • Design of single-photon detectors • Fabricating quantum-dot (QD) ensembles in conductive polymers • Modeling electrical and optical properties including robustness and sensitivity to QD-QD separation
Problem Statement and Motivation • Design, fabrication, characterization of QD-based optoelectronic devices as components of single-photon detectors • For underlying concepts see Mitra Dutta, et al., Colloidal Quantum Dots (QDs) in Optoelectronic Devices --- Solar Cells, Photodetectors, Light-emitting Diodes, in Handbook for SelfAssembled Semiconductor Nanostructures for Novel Devices in Photonics and Electronics, edited by M. Henini, Elsever Publ. (2008) and Ke Sun, Milana Vasudev, Hye-Son Jung, Jianyong Yang, Ayan Kar, Yang Li, Kitt Reinhardt, Preston Snee, Michael A. Stroscio, and Mitra Dutta, Applications of Colloidal Quantum Dots, Microelectronics Journal, 40, 644-649 (2009).
Key Achievements and Future Goals • Numerous simulations of electrical and optical properties including robustness and sensitivity to QD-QD separation • Numerous simulations for a variety of QD—conductivepolymer systems
• Current sensing AFM measurements of I-V curves for a variety of QDs embedded in conducting polymers
• Experimental characterization of integrated structures • Ultimate goal is realization of photodetectors capable of single-photon detection
Zheng Yang, Department of Electrical and Computer Engineering
Problem Statement and Motivation Diluted magnetic semiconductor is a kind of electronic materials with properties of both a semiconductor and a ferromagnetic material. In modern technology, semiconductor materials are used for logic devices such as the CPU in the computers due to its tunable electric conductivity under external electric field (arisen from the bandgap); while the ferromagnetic materials are used for memory devices such as the hard drive in the computers, in which the information storage is carried by the orientation of the majority spin polarization. Diluted magnetic semiconductor material is a combination of both. In a layman language, if a diluted magnetic semiconductor is successfully demonstrated, we may have the CPU and hard drive integrated in one device chip in our computers in the future. The major two obstacles hindering the practical application of diluted magnetic semiconductor are the Curie temperature and whether the ferromagnetism therein is intrinsic. Curie temperature is a critical temperature above which the material loses ferromagnetism.
Technical Approach Whether the ferromagnetism in the diluted magnetic semiconductor is intrinsic or not is determined by whether the spin polarization is carried by the free carriers or localized ions. If it is localized, sometime we call â&#x20AC;&#x153;extrinsicâ&#x20AC;?, it is not applicable for device applications generally. Several diluted magnetic semiconductors have been confirmed as intrinsic ferromagnetism such as Mn-doped GaAs, however, all of them show Curie temperature below room temperature. On the other hand, it has been observed above-room-temperature Curie temperatures in ZnO diluted magnetic semiconductor materials, but whether the ferromagnetism therein is intrinsic is still controversial and needs further clarification from experiments. The most straightforward experiment to investigate whether the ferromagnetism in diluted magnetic semiconductor is intrinsic or not is to study whether the ferromagnetism shows free carrier concentration dependent property.
Key Achievements and Future Goals It has been originally demonstrated that the free carrier concentration dependent ferromagnetism in ZnO diluted magnetic semiconductors. First, It has been experimentally achieved precise control of free carrier concentration in ZnO thin films with Ga doping. Then these ZnO thin films with different free carrier concentration were doped with magnetic dopants. It has been first time observed that the larger free carrier concentration leads to larger magnetization. Comprehensive electron microscopy and x-ray diffraction studies have been performed to exclude the possibility of the existence of localized magnetic clusters inside the ZnO diluted magnetic semiconductors. In the next steps, two major research projects will be carried out. The first is to study electrostatic doping (via a gate voltage instead of chemical doping) effect on the magnetic properties of ZnO diluted magnetic semiconductors. The second is to investigate the magnetic properties of ZnO diluted magnetic semiconductor in lowdimensional systems, such as nanowries.