Digital Commons Network^™

Statistical Simulation Models For Rayleigh And Rician Fading, Chengshan Xiao, Y. Rosa Zheng, N. C. Beaulieu

Electrical and Computer Engineering Faculty Research & Creative Works

New simulation models are proposed for Rayleigh and Rician fading channels. First, the statistical properties of Clarke's fading model with a finite number of sinusoids are analyzed. An improved Clarke's model is then proposed for the simulation of Rayleigh fading channels. Based on this improved Rayleigh fading model, a novel simulation model is proposed for Rician fading channels. The new Rician fading model employs a zero-mean stochastic sinusoid as the specular (line-of-sight) component, in contrast to all existing Rician fading simulators that utilize a non-zero mean deterministic specular component. The statistical properties of the proposed Rician fading model are analyzed …

The Subcircuit Extraction Problem, Nian Zhang, Donald C. Wunsch, Frank Harary

Electrical and Computer Engineering Faculty Research & Creative Works

The steady down scaling of CMOS device dimensions has been the main stimulus to the growth of microelectronics and computer aided very large scale integration (VLSI) design. But the more an integrated circuit (IC) is scaled, the higher its packing density becomes. The increasing size of chips, measured in either area or number of transistors, and the waste of the large capital investment involved in fabricating and testing circuits that do not work, make layout analysis and verification an important part of physical design automation. The most efficient way to overcome these difficulties is to identify a related collection of …

A Statistical Simulation Model For Mobile Radio Fading Channels, Chengshan Xiao, Y. Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

Recently, a Clarke's model-based simulator was proposed for Rayleigh fading channels. However, that model, as shown in this paper, may encounter statistic deficiency. Therefore, an improved model is presented to remove the statistic deficiency. Furthermore, a new simulation model is proposed for Rician fading channels. This Rician fading simulator with finite number of sinusoids plus a zero-mean stochastic sinusoid as the specular (line-of-sight) component is different from all the existing Rician fading simulators, which have non-zero mean deterministic specular component. The statistical properties of the proposed Rayleigh and Rician fading channel models are analyzed in detail, which shows that these …

Adaptive Critic Design Based Neurocontroller For A Statcom Connected To A Power System, Salman Mohagheghi, Jung-Wook Park, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

A novel nonlinear optimal neurocontroller for a static compensator (STATCOM) connected to a power system using artificial neural networks is presented in this paper. The heuristic dynamic programming (HDP), a member of the adaptive critic designs (ACDs) family, is used for the design of the STATCOM neurocontroller. This neurocontroller provides nonlinear optimal control with better performance compared to the conventional PI controllers.

Locating Moving Objects Over Mobile Sensor Network, Arvind Nath Rapaka, Sandeep Bogollu, Donald C. Wunsch, Ravindra Nath

Electrical and Computer Engineering Faculty Research & Creative Works

The purpose of our on going research would be to track entities, which enter their field of vision over the sensor network. Based on their sightings, they maintain a dynamic cache that can be queried by a base station- a stationary orfixed node. Since transmitting messages consumes a lot of energy, as against local processing and moreover the limited energy in sensor node does not allow heavy duty computing, we need to develop algorithms that will ensure efficient computing and minimal transmission without degradation of performance. and also data is stored locally, and memory is finite, the nodes must choose …

Dual Heuristic Programming Excitation Neurocontrol For Generators In A Multimachine Power System, Ganesh K. Venayagamoorthy, Donald C. Wunsch, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

The design of nonlinear optimal neurocontrollers that replace the conventional automatic voltage regulators for excitation control of turbogenerators in a multimachine power system is presented in this paper. The neurocontroller design is based on dual heuristic programming (DHP), a powerful adaptive critic technique. The feedback variables are completely based on local measurements from the generators. Simulations on a three-machine power system demonstrate that DHP-based neurocontrol is much more effective than the conventional proportional-integral-derivative control for improving dynamic performance and stability of the power grid under small and large disturbances. This paper also shows how to design optimal multiple neurocontrollers for …

Voltage Balancing Control Of Diode-Clamped Multilevel Rectifier/Inverter Systems, Zhiguo Pan, Keith Corzine, V. R. Stefanovic, J. M. Leuthen, Fang Zheng Peng

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a new voltage balancing control for the diode-clamped multilevel rectifier/inverter system. A complete analysis of the voltage balance theory for a 5-level back-to-back system is given. The analysis is based on fundamental frequency switching control and then extended to pulse-width modulation. The method involves obtaining optimal switching angles; a process which is described in detail in this paper. The proposed control strategy regulates the DC bus voltage, balances the capacitors, and decreases the harmonic components of the voltage and current. Simulation and experimental results demonstrate the validity of the optimizing method and control theory.

A Comparison Of Dual Heuristic Programming (Dhp) And Neural Network Based Stochastic Optimization Approach On Collective Robotic Search Problem, Nian Zhang, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

An important application of mobile robots is searching a region to locate the origin of a specific phenomenon. A variety of optimization algorithms can be employed to locate the target source, which has the maximum intensity of the distribution of some detected function. We propose two neural network algorithms: stochastic optimization algorithm and dual heuristic programming (DHP) to solve the collective robotic search problem. Experiments were carried out to investigate the effect of noise and the number of robots on the task performance, as well as the expenses. The experimental results showed that the performance of the dual heuristic programming …

Million City Traveling Salesman Problem Solution By Divide And Conquer Clustering With Adaptive Resonance Neural Networks, Samuel A. Mulder, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

The Traveling Salesman Problem (TSP) is a very hard optimization problem in the field of operations research. It has been shown to be NP-complete and is an often-used benchmark for new optimization techniques. One of the main challenges with this problem is that standard, non-AI heuristic approaches such as the Lin-Kernighan algorithm (LK) and the chained LK variant are currently very effective and in wide use for the common fully connected, Euclidean variant that is considered here. This paper presents an algorithm that uses adaptive resonance theory (ART) in combination with a variation of the Lin-Kernighan local optimization algorithm to …

Neural Networks Skin Tumor Diagnostic System, Zhao Zhang, William V. Stoecker, Randy Hays Moss

Electrical and Computer Engineering Faculty Research & Creative Works

In this study, a malignant melanoma diagnostic system is designed using a straightforward neural network with the back-propagation learning algorithm. Eleven features are automatically extracted from skin tumor images. The correct diagnostic rate of this system is better than the average rate of 16 dermatologists who based their diagnosis with only the slide images.

Probabilistic Neural Networks For Multi-Class Tissue Discrimination With Gene Expression Data, Rui Xu, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

With the emergence and rapid advancement of DNA microarray technologies, construction of gene expression profiles for different cancer types has already become a promising means for cancer diagnosis and treatment. Most previous research has focused on binary classification. Here, we use a probabilistic neural network (PNN) for multi-classification of cancer data. The experimental results demonstrate the effectiveness of the PNN in addressing gene expression data.

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 • …

Developing A Methodology To Detect Partial Failures For Dynamic Systems, Anwar A. Al-Jowder

Engineering Management & Systems Engineering Theses & Dissertations

The purpose of this research is to develop a decision support system that can assist in detecting partial failures in dynamic systems such as Fire Control System Tracking Radar (TR) onboard Naval Ships. Partial failures do not necessarily shut down the system immediately but cause degradation of operational performance. Previous work has shown that experts in the field of failure detection, test point insertion and Built-In-Test Equipment (BITE) can provide useful input in detecting partial failures. Partial failures affect operational system performance and support costs, which can be significant. Often, however, partial failure detection consists of the estimations and opinions …

Common- And Differential-Mode Signaling And Filtering, Zhe Li

Masters Theses

"Common-mode chokes are widely used as suppression filters against interference of common-mode noise in high-speed differential signaling. This thesis focuses on investigating the characteristics of common-mode chokes. Mixed-mode S-parameters are presented as a useful concept for explaining the modal operation of differential circuits.

Three methods for measuring common-mode and differentia-mode S-parameters of common-mode chokes are demonstrated. The three methods involve (1) ABCD chain matrix, 2) using hybrid couplers and 3) modal decomposition. Each measurement method provides a specific level of accuracy. The modal decomposition method can work up to 10GHz.

SPICE equivalent circuit model of common-mode chokes and the extraction …

An Invariance Transformation Algorithm For Defect Characterization Of Ultrasonic Signals For The Nondestructive Evaluation Of Concrete, Michael Dominic Ciocco

Theses and Dissertations

Nondestructive evaluation (NDE) techniques offer cost-effective strategies for monitoring the integrity of a variety of civil infrastructure, such as natural gas and sewer pipelines, without the need to take the system off-line. However, interpretation of NDE signals in terms of the location, size, and shape of underlying flaws in the material being inspected is fraught with difficulty. Typically, variations in the testing signal due to operational parameters have created a significant challenge for defect characterization. This thesis proposes, develops, and validates a defect characterization algorithm that compensates for operational variables and maps the test signal to a visual defect profile. …

Automated Segmentation Of Radiodense Tissue In Digitized Mammograms Using A Constrained Neyman-Pearson Classifier, Jeremy Thomas Neyhart

Theses and Dissertations

Breast cancer is the second leading cause of cancer related mortality among American women. Mammography screening has emerged as a reliable non-invasive technique for early detection of breast cancer. The radiographic appearance of the female breast consists of radiolucent (dark) regions and radiodense (light) regions due to connective and epithelial tissue. It has been established that the percentage of radiodense tissue in a patient's breast can be used as a marker for predicting breast cancer risk. This thesis presents the design, development and validation of a novel automated algorithm for estimating the percentage of radiodense tissue in a digitized mammogram. …

Chaotic Free-Space Laser Communication Over Turbulent Channel, N. F. Rulkov, Mikhail Vorontsov, L. Illing

Electro-Optics and Photonics Faculty Publications

The dynamics of errors caused by atmospheric turbulence in a self-synchronizing chaos-based communication system that stably transmits information over a ∼5  km free-space laser link is studied experimentally. Binary information is transmitted using a chaotic sequence of short-term pulses as a carrier. The information signal slightly shifts the chaotic time position of each pulse depending on the information bit. We report the results of an experimental analysis of the atmospheric turbulence in the channel and the impact of turbulence on the bit-error-rate performance of this chaos-based communication system.

A Reversible Three-Phase Step Up/Down Switching Mode Rectifier, Jenn-Jong Shieh

Journal of Marine Science and Technology–Taiwan

In this paper, focus on the null space vector duty cycle control, a reversible three-phase step up/down switching mode rectifier is proposed attain clean sinusoidal input current, unity power factor, bidirectional power flow, step up/down output DC voltage and insensitivity for a voltage input. In addition, a precise simulation model is proposed to simulation by using PC software tools. Finally, some simulation and experimental results are presented for verification.

An Assessment Of Seawinds On Quikscat Wind Retrieval, David Draper, David G. Long

Faculty Publications

The scatterometer ocean wind retrieval process produces several possible solutions or ambiguities at each point, requiring a separate ambiguity selection step to infer a unique wind vector field. An ambiguity selection error occurs when the selected wind vector is not the closest ambiguity to the true wind. The current ambiguity selection routine for SeaWinds is ad hoc, but performs well under most circumstances. Factors such as instrument noise and rain can also cause the estimated wind flow to deviate from the true wind. A quality assurance (QA) analysis is performed to assess the ambiguity selection effectiveness and noise level of …

An Optimum Greedy Algorithm For Choosing Minimal Set Of Conflicting Constraints In The Point Sequencing Problem, Florent Launay, Mitra Debasis

Electrical Engineering and Computer Science Faculty Publications

In this work, we first have proposed a technique to define the "causes" of inconsistency on an online point based reasoning constraint network. Second, we introduce an algorithm that proposes the user a minimal set of relations to remove when inconsistencies are detected. We have developed and implemented a battery of algorithms for the purpose of this type of reasoning. Some useful theorems and properties are defined for proving the 'minimal' aspect of the algorithm. Finally, we found that our investigation was a polynomially solvable sub problem of the vertex cover problem.

Training Fuzzy Systems With The Extended Kalman Filter, Daniel J. Simon

Electrical and Computer Engineering Faculty Publications

The generation of membership functions for fuzzy systems is a challenging problem. We show that for Mamdani-type fuzzy systems with correlation-product inference, centroid defuzzification, and triangular membership functions, optimizing the membership functions can be viewed as an identification problem for a nonlinear dynamic system. This identification problem can be solved with an extended Kalman filter. We describe the algorithm and compare it with gradient descent and with adaptive neuro-fuzzy inference system (ANFIS) based optimization of fuzzy membership functions. The methods discussed in this paper are illustrated on a fuzzy filter for motor winding current estimation, and are compared with Butterworth …

Dynamic Yield Analysis And Enhancement Of Fpga Reconfigurable Memory Systems, Minsu Choi, Nohpill Park

Electrical and Computer Engineering Faculty Research & Creative Works

This paper addresses the issues of field programmable gate arrays (FPGA) reconfigurable memory systems with faulty physical memory cells and proposes yield measurement techniques. Static yield (i.e., the yield which does not take into account the inherited redundancy utilization for repair) and dynamic yield (i.e., the yield which takes into account the inherited redundancy utilization for repair) of FPGA reconfigurable memory systems and their characteristics are extensively analyzed. Yield enhancement of conventional memory systems relies on additional redundancy, but FPGA reconfigurable memory systems have inherited redundancy and customizability. Thus, they can accommodate numerous target memory configurations, and redundant memory cells, …

Electromagnetic Scattering From A Gap In A Magneto-Dielectric Coating On An Infinite Ground Plane, George R. Simpson

Theses and Dissertations

The electromagnetic scattering from a gap in a magneto-dielectric coating on an infinite ground plane is analyzed. In this context, the gap forms a break only in the magneto-dielectric slab coating while the ground plane is continuous and unbroken. Volume equivalence is used to convert the gap region to one containing unknown volumetric equivalent electric and magnetic currents. The equivalent problem then is one of these currents radiating in the presence of an unbroken grounded magneto-dielectric slab. A Green's function for this geometry is developed consisting of two terms: a direct coupling term and correction term to account for the …

Source Localization In A Time-Varying Ocean Waveguide, Cristiano Soares, Martin Siderius, Sérgio M. Jesus

Electrical and Computer Engineering Faculty Publications and Presentations

One of the most stringent impairments in matched-field processing is the impact of missing or erroneous environmental information on the final source location estimate. This problem is known in the literature as model mismatch and is strongly frequency dependent. Another unavoidable factor that contributes to model mismatch is the natural time and spatial variability of the ocean waveguide. As a consequence, most of the experimental results obtained to date focus on short source-receiver ranges (usually <5 >km), stationary sources, reduced time windows and frequencies generally below 600 Hz. This paper shows that MFP source localization can be made robust to time–space …

Pattern Recognition For Electric Power System Protection, Yong Sheng

Doctoral Dissertations

The objective of this research is to demonstrate pattern recognition tools such as decision trees (DTs) and neural networks that will improve and automate the design of relay protection functions in electric power systems. Protection functions that will benefit from the research include relay algorithms for high voltage transformer protection (TP) and for high impedance fault (HIF) detection. A methodology, which uses DTs and wavelet analysis to distinguish transformer internal faults from other conditions that are easily mistaken for internal faults, has been developed. Also, a DT based solution is proposed to discriminate HIFs from normal operations that may confuse …

Evaluation Of Distributed Effects In Field Effect Transistors For High Frequency Applications, Srinivas Rowjee Cuddapah

Electrical & Computer Engineering Theses & Dissertations

Metal Semiconductor Field Effect Transistors are at the heart of currently used microwave and millimeter-wave devices. CAD (Computer Aided Design) models for MESFET are used in the development and optimization of high-speed microwave devices. The increase in the chip density demands more accurate models. A distributed small signal model was developed for a GaAs MESFET account of the high frequency effects.

The lumped model of the MESFET is inadequate at frequencies where the wavelength of operation approaches device dimensions. This is because different regions in the device can experience different amplitudes and phases of the biasing signal. In this thesis, …

Study Of Transport Properties Of Inas Using Monte Carlo Simulation, Satyanadh Gundimada

Electrical & Computer Engineering Theses & Dissertations

The present research is aimed at ascertaining the usefulness of InAs semiconductor material for single photon avalanche photo detectors operating in the Geiger mode at 2 μm wavelengths. InAs is considered as the material suitable for the purpose because of its less bandgap and lower effective mass of the electrons when compared to other semiconductor materials presently in use. Hence, theoretically transient transport properties of bulk InAs are superior and the velocity overshoot phenomena stronger. InAs is a relatively less explored material when compared to other materials like GaAs. The choice of the material is justified with thorough exploration of …

Yet Another Algorithm For Pitch Tracking (Yaapt), Kavita Kasi

Electrical & Computer Engineering Theses & Dissertations

This thesis presents a pitch detection algorithm that is extremely robust for both high quality and telephone speech. The kernel method for this algorithm is the Normalized Cross Correlation (NCCF) reported by David Talkin [16]. Major innovations include: processing of the original acoustic signal and a nonlinearly processed version of the signal to partially restore very weak F0 components; intelligent peak picking to select multiple F0 candidates and assign merit factors; and, incorporation of highly robust pitch contours obtained from smoothed versions of low frequency portions of spectrograms. Dynamic programming is used to find the ''best" pitch track among all …

Range-Dependent Seabed Characterization By Inversion Of Acoustic Data From A Towed Receiver Array, Martin Siderius, Peter L. Nielsen, Peter Gerstoft

Electrical and Computer Engineering Faculty Publications and Presentations

The MAPEX2000 experiments were conducted in the Mediterranean Sea in March, 2000 to determine seabed properties using a towed acoustic source and receiver array. Towed systems are advantageous because they are easy to deploy from a ship and the moving platform offers the possibility for estimating spatially variable (range-dependent) seabed properties. In this paper, seabed parameters are determined using a matched-field geoacoustic inversion approach with measured, towed array data. Previous research has successfully applied matched-field geoacoustic inversion techniques to measured acoustic data. However, in nearly all cases the inverted data were collected on moored, vertical receiver arrays. Results here show …

Application Of Maxwell Solvers To Pd Propagation. I. Concepts And Codes, David Pommerenke, S. Sakaguchi

Electrical and Computer Engineering Faculty Research & Creative Works

This article reviews the basic approaches to solving electromagnetic propagation in the context of PD detection. It also investigates available commercial software, introduces the steps required to obtain trustworthy computational results, and gives an example of detailed analysis of PD propagation.