Digital Commons Network^™

Common Information And Decentralized Inference With Dependent Observations, Ge Xu

Electrical Engineering and Computer Science - Dissertations

Wyner's common information was originally defined for a pair of dependent discrete random variables. This thesis generalizes its definition in two directions: the number of dependent variables can be arbitrary, so are the alphabets of those random variables. New properties are determined for the generalized Wyner's common information of multiple dependent variables. More importantly, a lossy source coding interpretation of Wyner's common information is developed using the Gray-Wyner network. It is established that the common information equals to the smallest common message rate when the total rate is arbitrarily close to the rate distortion function with joint decoding if the …

Rank Based Anomaly Detection Algorithms, Huaming Huang

Electrical Engineering and Computer Science - Dissertations

Anomaly or outlier detection problems are of considerable importance, arising frequently in diverse real-world applications such as finance and cyber-security. Several algorithms have been formulated for such problems, usually based on formulating a problem-dependent heuristic or distance metric. This dissertation proposes anomaly detection algorithms that exploit the notion of ``rank," expressing relative outlierness of different points in the relevant space, and exploiting asymmetry in nearest neighbor relations between points: a data point is ``more anomalous" if it is not the nearest neighbor of its nearest neighbors. Although rank is computed using distance, it is a more robust and higher level …

Identification Of A Target Using Its Natural Poles Using Both Frequency And Time Domain Response, Woojin Lee

Electrical Engineering and Computer Science - Dissertations

A new methodology for detection and identification of unknown objects in free space or on ground, or under the ground is presented in this dissertation. The Singularity Expansion Method (SEM) is introduced because it is possible to find the natural resonant frequencies of a scatterer from the scattered fields and use the resonant frequencies for identification. Many techniques to extract singularities of the EM response of an object are studied and then the Cauchy and the Matrix Pencil (MP) methods are chosen to carry out the processing. In the first part of the dissertation, a methodology for the computation of …

Methodology For Standby Leakage Power Reduction In Nanometer-Scale Cmos Circuits, Jae Woong Chun

Electrical Engineering and Computer Science - Dissertations

In nanometer-scale CMOS technology, leakage power has become a major component of the total power dissipation due to the downscaling of threshold voltage and gate oxide thickness. The leakage power consumption has received even more attention by increasing demand for mobile devices. Since mobile devices spend a majority of their time in a standby mode, the leakage power savings in standby state is critical to extend battery lifetime. For this reason, low power has become a major factor in designing CMOS circuits.

In this dissertation, we propose a novel transistor reordering methodology for leakage reduction. Unlike previous technique, the proposed …

Dynamic Thermal Management For Microprocessors, Yang Ge

Electrical Engineering and Computer Science - Dissertations

In deep submicron era, thermal hot spots and large temperature gradients significantly impact system reliability, performance, cost and leakage power. Dynamic thermal management techniques are designed to tackle the problems and control the chip temperature as well as power consumption. They refer to those techniques which enable the chip to autonomously modify the task execution and power dissipation characteristics so that lower-cost cooling solutions could be adopted while still guaranteeing safe temperature regulation. As long as the temperature is regulated, the system reliability can be improved, leakage power can be reduced and cooling system lifetime can be extended significantly.

Multimedia …

Method Of Moments Analysis Of An Aperture In A Thick Ground Plane, Ahmet Burak Olcen

Electrical Engineering and Computer Science - Dissertations

The problem of electromagnetic scattering from and transmission through an arbitrarily shaped aperture is considered. The aperture is in a thick infinite perfectly conducting ground plane. The conducting walls of the cavity inside the ground plane are of arbitrary shape. The apertures at both ends of the cavity are also of arbitrary shape. The structure is illuminated by an incident plane electromagnetic wave. The Green's function for this complicated problem is almost impossible to determine. Therefore the surface equivalence principle is used to reduce this complex problem into three simpler ones. Each such problem consists of equivalent surface currents radiating …

Design, Modeling And Analysis Of Non-Classical Field Effect Transistors, Peijie Feng

Electrical Engineering and Computer Science - Dissertations

Transistor scaling following per Moore's Law slows down its pace when entering into nanometer regime where short channel effects (SCEs), including threshold voltage fluctuation, increased leakage current and mobility degradation, become pronounced in the traditional planar silicon MOSFET. In addition, as the demand of diversified functionalities rises, conventional silicon technologies cannot satisfy all non-digital applications requirements because of restrictions that stem from the fundamental material properties. Therefore, novel device materials and structures are desirable to fuel further evolution of semiconductor technologies. In this dissertation, I have proposed innovative device structures and addressed design considerations of those non-classical field effect transistors …

Alignment, Clustering And Extraction Of Structured Motifs In Dna Promoter Sequences, Faisal Abdulmalek Alobaid

Electrical Engineering and Computer Science - Dissertations

A simple motif is a short DNA sequence found in the promoter region and believed to act as a binding site for a transcription factor protein. A structured motif is a sequence of simple motifs (boxes) separated by short sequences (gaps). Biologists theorize that the presence of these motifs play a key role in gene expression regulation. Discovering these patterns is an important step towards understanding protein-gene and gene-gene interaction thus facilitates the building of accurate gene regulatory network models. DNA sequence motif extraction is an important problem in bioinformatics. Many studies have proposed algorithms to solve the problem instance …

Self Similar Optical Fiber, Zheng-Xuan Lai

Electrical Engineering and Computer Science - Dissertations

This research proposes Self Similar optical fiber (SSF) as a new type of optical fiber. It has a special core that consists of self similar structure. Such a structure is obtained by following the formula for generating iterated function systems (IFS) in Fractal Theory. The resulted SSF can be viewed as a true fractal object in optical fibers. In addition, the method of fabricating SSF makes it possible to generate desired structures exponentially in numbers, whereas it also allows lower scale units in the structure to be reduced in size exponentially. The invention of SSF is expected to greatly ease …

Exploiting Data Locality In Dynamic Web Applications, Paul Talaga

Electrical Engineering and Computer Science - Dissertations

The Internet has grown from a static document retrieval system to a dynamic medium where users are both consumers and producers of information. Users may experience above-average website latencies due to the physical distances information must travel. Because user satisfaction is related to a website's responsiveness, e-commerce may be hindered and prevent online businesses from reaching their full potential.

This dissertation analyzes how temporal and relational dependencies in web applications limit their ability to become distributed. Two contributions are made, the first showing the location of data inside a datacenter influences the web system's performance, and secondly, that relaxing strict …

Intelligent Data Fusion For Applied Decision Support, Xiang Ye

Electrical Engineering and Computer Science - Dissertations

Data fusion technologies are widely applied to support a real-time decision-making in complicated, dynamically changing environments. Due to the complexity in the problem domain, artificial intelligent algorithms, such as Bayesian inference and particle swarm optimization, are employed to make the decision support system more adaptive and cognitive. This dissertation proposes a new data fusion model with an intelligent mechanism adding decision feedback to the system in real-time, and implements this intelligent data fusion model in two real-world applications.

The first application is designing a new sensor management system for a real-world and highly dynamic air traffic control problem. The main …

Method Of Moment Analysis Of Partially Shielded Chiral Bodies Of Revolution, Khaja Qutubuddin

Electrical Engineering and Computer Science - Dissertations

A chiral body of revolution (BOR) which is partially covered by a thin conducting shield is analyzed using the method of moments (MOM). The axisymmetric system is excited by a plane wave. The total internal fields and the far scattered fields are computed. The problem is solved using the surface equivalence principle. The scattered fields outside the structure are assumed to be produced by an equivalent magnetic surface current that exists on the unshielded part of the BOR surface and an external equivalent electric surface current that exists over all of the BOR surface . These two currents are assumed …

Arbitrarily Oriented Biaxially Anisotropic Media: Wave Behavior And Microstrip Antennas, Jennifer Warzala Graham

Electrical Engineering and Computer Science - Dissertations

This dissertation explores the electromagnetic behavior of arbitrarily oriented biaxially anisotropic media. An overview of wave behavior in biaxially anisotropic (or simply biaxial) media is presented. The reflection and transmission behaviors of electromagnetic waves from half-space and two-layer isotropic-biaxial interfaces are studied. The reflection and transmission coefficients are used in the formulation of eigenvector dyadic Green's functions. These Green's functions are employed in full-wave analyses of rectangular microstrip antennas printed on biaxial substrates.

The general characteristics of electrically biaxially anisotropic (biaxial) media are presented including permittivity tensors, optic axes, orientation of the medium, and birefringence. After a detailed discussion of …

State-Based Techniques For Designing, Verifying And Debugging Message Passing Systems, Rajaa Khaled Alqudah

Electrical Engineering and Computer Science - Dissertations

Message passing systems support the applications of concurrent events, where independent or semi-independent events occur simultaneously in a nondeterministic fashion. The nature of independence, random interactions and concurrency made the code development of such applications complicated and error-prone. Conventional code development environments or IDEs, such as Microsoft Visual Studio, provide little programming support in this regard. Furthermore, ensuring the correctness of a message passing system is a challenge. Typically, it is important to guarantee that a system meets its desired specifications along its construction process. Model checking is one of the techniques used in software verification which has proven to …

The Extended Preferred Ordering Theorem For Radar Tracking Using The Extended Kalman Filter, Donald Leskiw

Electrical Engineering and Computer Science - Dissertations

A certain problem in nonlinear estimation exists in radar tracking. Usually radar detections provide instantaneous position measurements in radar (polar) coordinates at discrete times, while tracks (estimated positions and motions over continuous time) are determined in rectangular coordinates; and the linear Kalman filter (LKF) is used as the estimator. Less common, the LKF is used to determine the tracks in radar coordinates, which are then converted into rectangular coordinates. Rarely is the extended Kalman filter (EKF) used, where the tracks are directly determined in rectangular coordinates from the radar detections via a local linearization. And so most radar tracks tend …

Characteristics Of The Fields In The Near And Far Zone Of Antennas And Its Significance In Wireless Communication, Arijit De

Electrical Engineering and Computer Science - Dissertations

The characterization of the fields radiated from antennas in wireless communication scenario has been mostly overlooked by communication society. The definition and application of Near-Field and Far-field has mostly been considered from the antenna measurement community. To date no critical study does exist for the evaluation of the far-field criterion in a wireless communication scenario. This dissertation tries to provide certain guidelines characterizing the near-field and the far-field using a Maxwellian framework. The implications of the near-field environment are then discussed. It appears that the concept of near and far fields are not clearly interpreted in the wireless communication literature. …

Performance And Memory Space Optimizations For Embedded Systems, Taylan Yemliha

Electrical Engineering and Computer Science - Dissertations

Embedded systems have three common principles: real-time performance, low power consumption, and low price (limited hardware). Embedded computers use chip multiprocessors (CMPs) to meet these expectations. However, one of the major problems is lack of efficient software support for CMPs; in particular, automated code parallelizers are needed.

The aim of this study is to explore various ways to increase performance, as well as reducing resource usage and energy consumption for embedded systems. We use code restructuring, loop scheduling, data transformation, code and data placement, and scratch-pad memory (SPM) management as our tools in different embedded system scenarios. The majority of …

Conditional Posterior Cramer-Rao Lower Bound And Distributed Target Tracking In Sensor Networks, Long Zuo

Electrical Engineering and Computer Science - Dissertations

Sequential Bayesian estimation is the process of recursively estimating the state of a dynamical system observed in the presence of noise. Posterior Cramer-Rao lower bound (PCRLB) sets a performance limit onany Bayesian estimator for the given dynamical system. The PCRLBdoes not fully utilize the existing measurement information to give anindication of the mean squared error (MSE) of the estimator in the future. In many practical applications, we are more concerned with the value of the bound in the future than in the past. PCRLB is an offline bound, because it averages out the very useful measurement information, which makes it …

The Differential Scheme And Quantum Computation, Robert J. Irwin

Electrical Engineering and Computer Science - Dissertations

It is well-known that standard models of computation are representable as simple dynamical systems that evolve in discrete time, and that systems that evolve in continuous time are often representable by dynamical systems governed by ordinary differential equations. In many applications, e.g., molecular networks and hybrid Fermi-Pasta-Ulam systems, one must work with dynamical systems comprising both discrete and continuous components.

Reasoning about and verifying the properties of the evolving state of such systems is currently a piecemeal affair that depends on the nature of major components of a system: e.g., discrete vs. continuous components of state, discrete vs. continuous time, …

Correlated Sources In Distributed Networks - Data Transmission, Common Information Characterization And Inferencing, Wei Liu

Electrical Engineering and Computer Science - Dissertations

Correlation is often present among observations in a distributed system. This thesis deals with various design issues when correlated data are observed at distributed terminals, including: communicating correlated sources over interference channels, characterizing the common information among dependent random variables, and testing the presence of dependence among observations.

It is well known that separated source and channel coding is optimal for point-to-point communication. However, this is not the case for multi-terminal communications. In this thesis, we study the problem of communicating correlated sources over interference channels (IC), for both the lossless and the lossy case. For lossless case, a sufficient …

Noise-Enhanced And Human Visual System-Driven Image Processing: Algorithms And Performance Limits, Renbin Peng

Electrical Engineering and Computer Science - Dissertations

This dissertation investigates the problem of image processing based on stochastic resonance (SR) noise and human visual system (HVS) properties, where several novel frameworks and algorithms for object detection in images, image enhancement and image segmentation as well as the method to estimate the performance limit of image segmentation algorithms are developed.

Object detection in images is a fundamental problem whose goal is to make a decision if the object of interest is present or absent in a given image. We develop a framework and algorithm to enhance the detection performance of suboptimal detectors using SR noise, where we add …

A Single-Field Finite-Difference Time-Domain Formulations For Electromagnetic Simulations, Gokhan Aydin

Electrical Engineering and Computer Science - Dissertations

In this dissertation, a set of general purpose single-field finite-difference time-domain updating equations for solving electromagnetic problems is derived. The formulation uses a single-field expression for full-wave solution. This formulation can provide numerical results similar to those obtained using the traditional formulation with less required computer resources.

Traditional finite-difference time-domain updating equations are based on Maxwell's curl equations whereas the single-field updating equations used here are based on the vector wave equation. General formulations are derived for normal and oblique incidence plane wave cases for linear, isotropic, homogeneous and non-dispersive as well as dispersive media.

To compare the single-field updating …

Decision-Making With Heterogeneous Sensors - A Copula Based Approach, Satish Giridhar Iyengar

Electrical Engineering and Computer Science - Dissertations

Statistical decision making has wide ranging applications, from communications and signal processing to econometrics and finance. In contrast to the classical one source-one receiver paradigm, several applications have been identified in the recent past that require acquiring data from multiple sources or sensors. Information from the multiple sensors are transmitted to a remotely located receiver known as the fusion center which makes a global decision. Past work has largely focused on fusion of information from homogeneous sensors. This dissertation extends the formulation to the case when the local sensors may possess disparate sensing modalities. Both the theoretical and practical aspects …

Towards An Information Theoretic Framework For Evolutionary Learning, Stuart William Card

Electrical Engineering and Computer Science - Dissertations

The vital essence of evolutionary learning consists of information flows between the environment and the entities differentially surviving and reproducing therein. Gain or loss of information in individuals and populations due to evolutionary steps should be considered in evolutionary algorithm theory and practice. Information theory has rarely been applied to evolutionary computation - a lacuna that this dissertation addresses, with an emphasis on objectively and explicitly evaluating the ensemble models implicit in evolutionary learning. Information theoretic functionals can provide objective, justifiable, general, computable, commensurate measures of fitness and diversity.

We identify information transmission channels implicit in evolutionary learning. We define …

Cognitive Security Framework For Heterogeneous Sensor Network Using Swarm Intelligence, Rajani Muraleedharan

Electrical Engineering and Computer Science - Dissertations

Rapid development of sensor technology has led to applications ranging from academic to military in a short time span. These tiny sensors are deployed in environments where security for data or hardware cannot be guaranteed. Due to resource constraints, traditional security schemes cannot be directly applied. Unfortunately, due to minimal or no communication security schemes, the data, link and the sensor node can be easily tampered by intruder attacks. This dissertation presents a security framework applied to a sensor network that can be managed by a cohesive sensor manager. A simple framework that can support security based on situation assessment …

Protection Models For Web Applications, Karthick Jayaraman

Electrical Engineering and Computer Science - Dissertations

Early web applications were a set of static web pages connected to one another. In contrast, modern applications are full-featured programs that are nearly equivalent to desktop applications in functionality. However, web servers and web browsers, which were initially designed for static web pages, have not updated their protection models to deal with the security consequences of these full-featured programs. This mismatch has been the source of several security problems in web applications.

This dissertation proposes new protection models for web applications. The design and implementation of prototypes of these protection models in a web server and a web browser …

Network-Aware Active Wardens In Ipv6, Grzegorz Lewandowski

Electrical Engineering and Computer Science - Dissertations

Every day the world grows more and more dependent on digital communication. Technologies like e-mail or the World Wide Web that not so long ago were considered experimental, have first become accepted and then indispensable tools of everyday life. New communication technologies built on top of the existing ones continuously race to provide newer and better functionality. Even established communication media like books, radio, or television have become digital in an effort to avoid extinction. In this torrent of digital communication a constant struggle takes place. On one hand, people, organizations, companies and countries attempt to control the ongoing communications …

Intelligent Processing In Wireless Communications Using Particle Swarm Based Methods, Weihua Gao

Electrical Engineering and Computer Science - Dissertations

There are a lot of optimization needs in the research and design of wireless communica- tion systems. Many of these optimization problems are Nondeterministic Polynomial (NP) hard problems and could not be solved well. Many of other non-NP-hard optimization problems are combinatorial and do not have satisfying solutions either. This dissertation presents a series of Particle Swarm Optimization (PSO) based search and optimization algorithms that solve open research and design problems in wireless communications. These problems are either avoided or solved approximately before.

PSO is a bottom-up approach for optimization problems. It imposes no conditions on the underlying problem. Its …