Electrical and Computer Engineering Commons^™

Quantum Mechanical Analysis Of Channel Access Geometry And Series Resistance In Nanoscale Transistors, R. Venugopal, S. Goasguen, Supriyo Datta, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

We apply a two-dimensional quantum mechanical simulation scheme to study the effect of channel access geometries on device performance. This simulation scheme solves the nonequilibrium Green’s function equations self-consistently with Poisson’s equation and treats the effect of scattering using a simple approximation inspired by Büttiker. It is based on an expansion of the device Hamiltonian in coupled mode space. Simulation results are used to highlight quantum effects and discuss the importance of scattering when examining the transport properties of nanoscale transistors with differing channel access geometries. Additionally, an efficient domain decomposition scheme for evaluating the performance of nanoscale transistors is …

Quality Challenges In E-Commerce Websites, Ronan Fitzpatrick

Conference papers

No abstract provided.

Kalman Filtering For Adaptive Nonuniformity Correction In Infrared Focal-Plane Arrays, Sergio N. Torres, Majeed M. Hayat

Electrical and Computer Engineering Faculty Research and Publications

A novel statistical approach is undertaken for the adaptive estimation of the gain and bias nonuniformity in infrared focal-plane array sensors from scene data. The gain and the bias of each detector are regarded as random state variables modeled by a discrete-time Gauss–Markov process. The proposed Gauss–Markov framework provides a mechanism for capturing the slow and random drift in the fixed-pattern noise as the operational conditions of the sensor vary in time. With a temporal stochastic model for each detector’s gain and bias at hand, a Kalman filter is derived that uses scene data, comprising the detector’s readout values sampled …

Breakdown Probabilities For Thin Heterostructure Avalanche Photodiodes, Majeed M. Hayat, Ünal Sako ̆Glu, Oh-Hyun Kwon, Shuling Wang, Joe C. Campbell, Bahaa E.A. Saleh, Malvin Carl Teich

Electrical and Computer Engineering Faculty Research and Publications

The recurrence theory for the breakdown probability in avalanche photodiodes (APDs) is generalized to heterostructure APDs that may have multiple multiplication layers. The generalization addresses layer-boundary effects such as the initial energy of injected carriers as well as the layer-dependent profile of the dead space in the multiplication region. Reducing the width of the multiplication layer serves to both downshift and sharpen the breakdown probability curve as a function of the applied reverse-bias voltage. In structures where the injected carriers have an initial energy that is comparable to the ionization threshold energy, the transition from linear mode to Geiger-mode is …

Tcm Decoding Using Neural Networks, Edit J. Kaminsky, Nikhil Deshpande

Electrical Engineering Faculty Publications

This paper presents a neural decoder for trellis coded modulation (TCM) schemes. Decoding is performed with Radial Basis Function Networks and Multi-Layer Perceptrons. The neural decoder effectively implements an adaptive Viterbi algorithm for TCM which learns communication channel imperfections. The implementation and performance of the neural decoder for trellis encoded 16-QAM with amplitude imbalance are analyzed.

Processor Microarchitecture For Implementation Of Ephemeral State Processing Within Network Routers, Muthulakshmi Muthukumarasamy

Theses and Dissertations--Electrical and Computer Engineering

The evolving concept of Ephemeral State Processing (ESP) is overviewed. ESP allows development of new scalable end-to-end network user services. An evolving macro-level language is being developed to support ESP at the network node level. Three approaches for implementing ESP services at network routers can be considered. One approach is to use the existing processing capability within commercially available network routers. Another approach is to add a small scale existing ASIC based general-purpose processor to an existing network router. This thesis research concentrates on a third approach of developing a special-purpose programmable Ephemeral State Processor (ESPR) Instruction Set Architecture (ISA) …

Larger-First Partial Parsing, Sebastian Alexander Van Delden

Retrospective Theses and Dissertations

Larger-first partial parsing is a primarily top-down approach to partial parsing that is opposite to current easy-first, or primarily bottom-up, strategies. A rich partial tree structure is captured by an algorithm that assigns a hierarchy of structural tags to each of the input tokens in a sentence. Part-of-speech tags are first assigned to the words in a sentence by a part-of-speech tagger. A cascade of Deterministic Finite State Automata then uses this part-of-speech information to identify syntactic relations primarily in a descending order of their size. The cascade is divided into four specialized sections: (1) a Comma Network, which identifies …

Optimal Excess Noise Reduction In Thin Heterojunction Al0.6Ga0.4As-Gaas Avalanche Photodiodes, Oh-Hyun Kwon, Majeed M. Hayat, Shuling Wang, Joe C. Campbell, Archie L. Holmes, Yi Pan, Bahaa E.A. Saleh, Malvin Carl Teich

Electrical and Computer Engineering Faculty Research and Publications

It has been recently found that the initial-energy effect, which is associated with the finite initial energy of carriers entering the multiplication region of an avalanche photodiode (APD), can be tailored to reduce the excess noise well beyond the previously known limits for thin APDs. However, the control of the initial energy of injected carriers can be difficult in practice for an APD with a single multiplication layer. In this paper, the dead-space multiplication recurrence theory is used to show that the low noise characteristics associated with the initial-energy effect can be achieved by utilizing a two-layer multiplication region. As …

Scene-Based Nonuniformity Correction For Focal Plane Arrays By The Method Of The Inverse Covariance Form, Sergio N. Torres, Jorge E. Pezoa, Majeed M. Hayat

Electrical and Computer Engineering Faculty Research and Publications

What is to our knowledge a new scene-based algorithm for nonuniformity correction in infrared focal-plane array sensors has been developed. The technique is based on the inverse covariance form of the Kalman filter (KF), which has been reported previously and used in estimating the gain and bias of each detector in the array from scene data. The gain and the bias of each detector in the focal-plane array are assumed constant within a given sequence of frames, corresponding to a certain time and operational conditions, but they are allowed to randomly drift from one sequence to another following a discrete-time …

Modeling, Fabrication, And Optimization Of Niobium Cavities: Final Phase, Robert A. Schill Jr., Mohamed Trabia

Transmutation Sciences Materials (TRP)

Niobium cavities are important parts of the integrated NC/SC high-power linacs. Over the years, researchers in several countries have tested various cavity shapes. They concluded that elliptically shaped cells are the most appropriate shape for superconducting cavities. The need for very clean surfaces lead to the use of a buffered chemical polishing produce for surface cleaning to get good performance of the cavities. This is the third and final phase of the study.

The first phase has resulted in improving the basic understanding of multipacting and the process of chemical etching. The second phase has resulted in an experimental setup …

Modeling, Fabrication, And Optimization Of Niobium Cavities, Robert A. Schill Jr., Mohamed Trabia, William Culbreth

Transmutation Sciences Materials (TRP)

One of the key technologies for the deployment of accelerator driven transmutation systems is the accelerator itself. To increase the efficiency of the high-power accelerators needed to support the transmutation mission, the national and international accelerator teams have proposed using elliptical superconducting niobium cavities. This project is tasked with examining the impacts of the design and fabrication technologies for these elliptical niobium cavities on their performance. Niobium was selected primarily due to its behavior at low temperatures.

One of the major sources of energy loss from a superconducting accelerator cavity is a process known as multiple impacting (or “multipacting”) of …

Frequency-Hopped Multiple-Access Communications With Noncoherent M-Ary Ofdm-Ask, A. Al-Dweik, Fuqin Xiong

Electrical and Computer Engineering Faculty Publications

A noncoherent, bandwidth-efficient modulation scheme is proposed for frequency-hopping multiple-access (FH-MA) networks. The proposed scheme is a combination of noncoherent M-ary amplitude-shift keying (NMASK) and orthogonal frequency-division multiplexing (OFDM). Using this scheme minimizes the required data bandwidth. The number of frequency slots available to the users increases significantly for a fixed spread-spectrum bandwidth (BW_SS). The effect of the multiple-access interference is reduced. Simple and accurate bit error rate expressions have been derived for FH-OFDM-MASK in additive white Gaussian noise channels and for FH-OFDM-ASK in Rayleigh fading channels.

Formation Of Porous Silicon Through The Nanosized Pores Of An Anodized Alumina Template, Biswajit Das, S. P. Mcginnis

Electrical & Computer Engineering Faculty Research

This letter demonstrates the ability to fabricate porous silicon through the nanoscale pores of an anodized alumina template formed on a silicon substrate. The alumina template acts as a protective coating on the porous silicon surface increasing its mechanical integrity, thus eliminating the need for delicate handling that is usually required for this material system. The optical properties of the porous silicon formed through the template show characteristics similar to that of normally formed porous silicon. In addition, the porous siliconoptical properties show very little degradation with time; the alumina coating is believed to contribute to this improved stability. The …

Source Motion Mitigation For Adaptive Matched Field Processing, Lisa M. Zurk, Nigel Lee, James Ward

Electrical and Computer Engineering Faculty Publications and Presentations

Application of adaptive matched field processing to the problem of detecting quiet targets in shallow water is complicated by source motion, both the motion of the target and the motion of discrete interferers. Target motion causes spreading of the target peak, thereby reducing output signal power. Interferer motion increases the dimensionality of the interference subspace, reducing adaptive interference suppression. This paper presents three techniques that mitigate source motion problems in adaptive matched field processing. The first involves rank reduction, which enables adaptive weight computation over short observation intervals where motion effects are less pronounced. The other two techniques specifically compensate …

A Hierarchical Approach To Computer-Aided Design Of Quantum Circuits, Marek Perkowski, Martin Lukac, Pawel Kerntopf, Mikhail Pivtoraiko, Michele Folgheraiter, Yong Woo Choi, Jung-Wook Kim, Dongsoo Lee, Woong Hwangbo, Hyungock Kim

Electrical and Computer Engineering Faculty Publications and Presentations

A new approach to synthesis of permutation class of quantum logic circuits has been proposed in this paper. This approach produces better results than the previous approaches based on classical reversible logic and can be easier tuned to any particular quantum technology such as nuclear magnetic resonance (NMR). First we synthesize a library of permutation (pseudobinary) gates using a Computer-Aided-Design approach that links evolutionary and combinatorics approaches with human experience and creativity. Next the circuit is designed using these gates and standard 1*1 and 2*2 quantum gates and finally the optimizing tautological transforms are applied to the circuit, producing a …

Use Of Machine Learning Based On Constructive Induction In Dialogs With Robotic Heads, Marek Perkowski, Tsutomu Sasao, Atsumu Iseno, Uland Wong, Martin Lukac, David Ng, Miranda Fix, Karl Kuchs, Mikhail Pivtoraiko, Michele Folgheraiter

Electrical and Computer Engineering Faculty Publications and Presentations

Paper presents our research progress and experiences related to designing inexpensive natural-size humanoid caricature and realistic robot heads - actors for robot theatre, agents for advertisement, education and entertainment. We concentrate on Machine Learning techniques used to teach robots behaviors, natural language dialogs and facial gestures.

Reversible Logic Synthesis With Cascades Of New Family Of Gates, Mozammel H.A. Khan, Marek Perkowski

Electrical and Computer Engineering Faculty Publications and Presentations

Reversible circuits are currently on of top approaches to power minimization and the one whose importance will be only growing with time. In this paper, the well known Feynman gate is generalized to k*k gate and a new generalized k*k family of reversible gates is proposed. A synthesis method for multi-output SOP function using cascades of the new gate family is presented. For utilizing the benefit of product sharing among the output functions, two graph-based data structures are used. Another synthesis method for AND-OR-EXOR function using cascades of the new gate family and generalized Feynman gate is also presented. Synthesis …

Biology Goes Digital: An Array Of 5,700 Spartan Fpgas Brings The Biowall To "Life", Christof Teuscher, Gianluca Tempesti

Electrical and Computer Engineering Faculty Publications and Presentations

A unique, scientific research instrument and art piece, the BioWall models bio-inspired electronic tissues capable of evolution, selfrepair, self-replication – and learning. Much pure and applied scientific research has focused on replicating biological functions in digital hardware. Here, at the Logic Systems Laboratory of the Swiss Federal Institute of Technology in Lausanne (EPFL), we have utilized 5,700 Xilinx Spartan™ FPGAs, in multiple configurations, to build bio-inspired computing machines that exploit three essential biological models: • Phylogenesis – the history of the evolution of the species • Ontogenesis – the development of an individual as directed by his genetic code • …

A Shape-Based Approach To Change Detection Of Lakes Using Time Series Remote Sensing Images, Jiang Li, Ram M. Narayanan

Department of Electrical and Computer Engineering: Faculty Publications

Shape analysis has not been considered in remote sensing as extensively as in other pattern recognition applications. However, shapes such as those of geometric patterns in agriculture and irregular boundaries of lakes can be extracted from the remotely sensed imagery even at relatively coarse spatial resolutions. This paper presents a procedure for efficiently retrieving and representing shapes of interesting features in remotely sensed imagery using supervised classification, object recognition, parametric contour tracing, and proposed piecewise linear polygonal approximation techniques. In addition, shape similarity can be measured by means of a computationally efficient metric. The study was conducted on a time …

United States Patent Application Publication: Divide And Conquer System And Method Of Dna Sequence Assembly, Khalid Sayood, Hasan H. Otu

Department of Electrical and Computer Engineering: Faculty Publications

The present invention provides a new algorithm for assembling fragments from a long DNA sequence. The algorithm of the invention Solves simultaneously fragment assembly-related problems. Such as the fragment orientation, overlap and layout phases. This is achieved by clustering fragments with respect to their Average Mutual Information (AMI) profiles using the k-means algorithm.