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Electrical and Computer Engineering Faculty Research & Creative Works

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Articles 2491 - 2520 of 3518

Full-Text Articles in Engineering

Modern Laboratory-Based Education For Power Electronics And Electric Machines, Robert S. Balog, Zakdy Sorchini, Jonathan W. Kimball, Patrick L. Chapman, Philip T. Krein May 2005

Modern Laboratory-Based Education For Power Electronics And Electric Machines, Robert S. Balog, Zakdy Sorchini, Jonathan W. Kimball, Patrick L. Chapman, Philip T. Krein

Electrical and Computer Engineering Faculty Research & Creative Works

The study of modern energy conversion draws upon a broad range of knowledge and often requires a fair amount of experience. This suggests that laboratory instruction should be an integral component of a power electronics and electric machines curriculum. However, before a single watt can be processed in a realistic way, the student must understand not only the operation of conversion systems but also more advanced concepts such as control theory, speed and position sensing, switching signal generation, gate drive isolation, circuit layout, and other critical issues. Our approach is to use a blue-box module where these details are pre-built …

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Glucose Oxidase (God)-Coupled Amperometric Microsensor With Integrated Electrochemical Actuation System, Jongwon Park, Chang-Soo Kim, Minsu Choi, Shanrui Zhang May 2005

Glucose Oxidase (God)-Coupled Amperometric Microsensor With Integrated Electrochemical Actuation System, Jongwon Park, Chang-Soo Kim, Minsu Choi, Shanrui Zhang

Electrical and Computer Engineering Faculty Research & Creative Works

Recent developments for biosensors have been mainly focused on miniaturization and exploratory use of new materials. It should be emphasized that the absence of a novel "in-situ self-calibration/diagnosis technique" that is not connected to an external apparatus is a key obstacle to the realization of a biosensor for continuous use with minimum attendance. In order to address this issue, a novel solid-state glucose oxidase-coupled amperometric biosensor with integrated electrochemical actuation system has been designed and validated. There are two key components of the proposed glucose biosensor: solid-state GOD-coupled thin-lm amperometric sensing element and O2 depleting/saturating built-in electrochemical actuator. The …

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Advanced Control Of Cascaded Multilevel Drives Based On P-Q Theory, Shuai Lu, Keith Corzine, T. H. Fikse May 2005

Advanced Control Of Cascaded Multilevel Drives Based On P-Q Theory, Shuai Lu, Keith Corzine, T. H. Fikse

Electrical and Computer Engineering Faculty Research & Creative Works

In recent years, there has been significant development on the cascaded multilevel inverter wherein the series connection is accomplished by splitting the neutral point of the load and driving both ends with power converters. This splits the power between a "bulk" inverter supplying higher-voltage low-frequency power and a "conditioning" inverter supplying low-voltage high-frequency power and leads to exceptional power quality which is necessary in applications such as naval propulsion that require extremely low THD. This paper reports the development of a new control method for the cascaded multi-level inverter. The primary advantage of this new control is that the bulk …

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Dielectric Material Characterization By Complex Ratio Of Embedded Modulated Scatterer Technique States, Gabriel S. Freiburger, R. Zoughi May 2005

Dielectric Material Characterization By Complex Ratio Of Embedded Modulated Scatterer Technique States, Gabriel S. Freiburger, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

The embedded modulated scatterer technique (MST) is an innovative tool which can be used for microwave dielectric characterization of infrastructure and composite structures. By impinging a microwave signal on a loaded thin dipole antenna embedded in a material whose dielectric properties are sought, the resulting refelction data can be used to inversely solve for the dielectric properties of interest. Previous investigations utilized reflection information from a single loaded dipole and required known system parameters, such as radiator polarization vs. dipole alignment and relative distance between radiator and probe, to solve for the sought-for dielectric properties. This paper explores a unique …

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Microwave Reflectometry As A Novel Diagnostic Method For Detection Of Skin Cancers, Kundan Chand, Pratik Mehta, Daryl G. Beetner, R. Zoughi, William V. Stoecker May 2005

Microwave Reflectometry As A Novel Diagnostic Method For Detection Of Skin Cancers, Kundan Chand, Pratik Mehta, Daryl G. Beetner, R. Zoughi, William V. Stoecker

Electrical and Computer Engineering Faculty Research & Creative Works

More than one million people are diagnosed with skin cancer each year in the United States and more than ten thousand people die from the disease. Currently, there are some methods for early detection of skin cancers, like visual inspection, but improvements are needed. This paper presents a method involving microwave reflectometry as a diagnostic tool for detection of skin cancers. The results of measurements and simulations for normal and wet skin have been shown to distinguish among skin samples with different properties. Microwave measurements from lesions have also been presented which are used to distinguish between cancerous and benign …

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Millimeter Wave Detection Of Localized Anomalies In The Space Shuttle External Fuel Tank Insulating Foam And Acreage Heat Tiles, Sergey Kharkovsky, R. Zoughi, J. T. Case, F. L. Hepburn May 2005

Millimeter Wave Detection Of Localized Anomalies In The Space Shuttle External Fuel Tank Insulating Foam And Acreage Heat Tiles, Sergey Kharkovsky, R. Zoughi, J. T. Case, F. L. Hepburn

Electrical and Computer Engineering Faculty Research & Creative Works

Undesired manufactured or in-service produced anomalies in the form of voids in the SOFI and unbonds in the heat tiles can significantly reduce their designed effectiveness. Additionally, unbonds in the heat tiles may cause their complete separation from the fuselage exposing it to extreme heat. Millimeter wave NDT methods are viable candidate for life-cycle inspection of the SOFI and the acreage heat tiles of the Space Shuttle fleet. The results of these investigations described in this paper clearly showed the utility of these methods for detecting localized anomalies in thick SOFI and acreage heat tiles. These methods are fast and …

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Wide-Band Lorentzian Media In The Fdtd Algorithm, Marina Koledintseva, James L. Drewniak, David Pommerenke, Giulio Antonini, Antonio Orlandi, Konstantin Rozanov May 2005

Wide-Band Lorentzian Media In The Fdtd Algorithm, Marina Koledintseva, James L. Drewniak, David Pommerenke, Giulio Antonini, Antonio Orlandi, Konstantin Rozanov

Electrical and Computer Engineering Faculty Research & Creative Works

This paper considers the case of a wide-band Lorentzian (WBL) algorithm in the finite-difference time-domain (FDTD) modeling of dispersive media. It is shown herein that the WBL model is a physically meaningful and practically useful case of the frequency behavior of materials along with the Debye and narrow-band Lorentzian (NBL). The recursive convolution algorithms for the finite-difference time-domain technique for NBL and WBL models differ. The Debye model, which is suitable for comparatively low-frequency dispersive materials, may not have sufficient number of parameters for describing the wide-band material, especially if this material exhibits pronounced absorption at higher frequencies. It is …

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Coupling Between Differential Signals And The Dc Power-Bus In Multilayer Pcbs, Chen Wang, Marco Leone, James L. Drewniak, Antonio Orlandi May 2005

Coupling Between Differential Signals And The Dc Power-Bus In Multilayer Pcbs, Chen Wang, Marco Leone, James L. Drewniak, Antonio Orlandi

Electrical and Computer Engineering Faculty Research & Creative Works

Differential and common-mode transfer impedances are proposed herein to analyze noise coupled to (from) the dc power-bus from (to) via transitions in differential signals. Expressions for the two transfer impedances in terms of conventional single-ended transfer impedances are derived and verified through measurements, full-wave finite-difference time-domain (FDTD) simulations and an analytical cavity model. Some properties of the differential and common-mode transfer impedances are investigated to facilitate engineering design. The impact of signal current imbalances on power-bus noise and the benefit of differential signals as compared to single-ended signals are quantified.

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Survey Of Clustering Algorithms, Rui Xu, Donald C. Wunsch May 2005

Survey Of Clustering Algorithms, Rui Xu, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

Data analysis plays an indispensable role for understanding various phenomena. Cluster analysis, primitive exploration with little or no prior knowledge, consists of research developed across a wide variety of communities. The diversity, on one hand, equips us with many tools. On the other hand, the profusion of options causes confusion. We survey clustering algorithms for data sets appearing in statistics, computer science, and machine learning, and illustrate their applications in some benchmark data sets, the traveling salesman problem, and bioinformatics, a new field attracting intensive efforts. Several tightly related topics, proximity measure, and cluster validation, are also discussed.

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Wthd-Optimal Staircase Modulation Of Single-Phase Multilevel Inverters, B. Diong, Keith Corzine May 2005

Wthd-Optimal Staircase Modulation Of Single-Phase Multilevel Inverters, B. Diong, Keith Corzine

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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User-Controlled, Multimedia-Enhanced Communication Using Prior Knowledge And Experience, S. R. Subramanya, Byung K. Yi Apr 2005

User-Controlled, Multimedia-Enhanced Communication Using Prior Knowledge And Experience, S. R. Subramanya, Byung K. Yi

Electrical and Computer Engineering Faculty Research & Creative Works

This article focuses on enriching the communication, experience between human beings interacting through different kind of devices, including mobile phones and PDAs. the key point is how to effectively exploit multimedia data to enhance the richness of communication without overloading the communication channel. to this end, the system tries to minimize the quantity of information transmitted over the networks and to maximize the usage of locally stored information. the proposed system sends several kinds of data, including continuous video, video clips, still images, and avatars, over the communication channel. the specific data that are sent are based on the parameters …

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Size Evaluation Of Corrosion Precursor Pitting Using Near-Field Millimeter Wave Nondestructive Testing Methods, Mohammad Tayeb Ahmad Ghasr, Brian D. Carroll, Sergey Kharkovsky, R. Zoughi, R. Austin Apr 2005

Size Evaluation Of Corrosion Precursor Pitting Using Near-Field Millimeter Wave Nondestructive Testing Methods, Mohammad Tayeb Ahmad Ghasr, Brian D. Carroll, Sergey Kharkovsky, R. Zoughi, R. Austin

Electrical and Computer Engineering Faculty Research & Creative Works

Early detection of corrosion precursor pitting and estimation of its overall dimensions directly affects the required effort and cost associated with repair and maintenance of critical aircraft structural components. The magnitude and phase of a reflected signal from a pitting are directly related to its dimensions. This paper presents a millimeter wave probe and a sizing procedure used to detect and evaluate overall pitting dimensions.

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Analysis And Design Of Switched Capacitor Converters, Jonathan W. Kimball, Philip T. Krein Mar 2005

Analysis And Design Of Switched Capacitor Converters, Jonathan W. Kimball, Philip T. Krein

Electrical and Computer Engineering Faculty Research & Creative Works

Switched capacitor converters have become more common in recent years. Crucial to understanding the maximum power throughput and efficiency is a model of the converter's equivalent resistance. A new form for equivalent resistance is derived and discussed in a design context. Quasi-resonant operation is also explored and compared to non-resonant operation. Several capacitor technologies are evaluated and compared.

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The Matrix Pencil For Power System Modal Extraction, A. Singh, Mariesa Crow Feb 2005

The Matrix Pencil For Power System Modal Extraction, A. Singh, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

This work introduces the matrix pencil modal extraction method through the use of several illustrative examples. This method is used to estimate the eigenvalues of reduced-order models of large nonlinear systems based on their dynamic responses.

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Improving Voltage Stability By Reactive Power Reserve Management, Feng Dong, Badrul H. Chowdhury, Mariesa Crow, Levent Acar Feb 2005

Improving Voltage Stability By Reactive Power Reserve Management, Feng Dong, Badrul H. Chowdhury, Mariesa Crow, Levent Acar

Electrical and Computer Engineering Faculty Research & Creative Works

The amount of reactive reserves at generating stations is a measure of the degree of voltage stability. With this perspective, an optimized reactive reserve management scheme based on the optimal power flow is proposed. Detailed models of generator limiters, such as those for armature and field current limiting must be considered in order to utilize the maximum reactive power capability of generators, so as to meet reactive power demands during voltage emergencies. Participation factors for each generator in the management scheme are predetermined based on the voltage-var (V-Q) curve methodology. The Bender's decomposition methodology is applied to the reactive reserve …

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Pulse Regulation Control Technique For Integrated High-Quality Rectifier-Regulators, Mehdi Ferdowsi, Ali Emadi Feb 2005

Pulse Regulation Control Technique For Integrated High-Quality Rectifier-Regulators, Mehdi Ferdowsi, Ali Emadi

Electrical and Computer Engineering Faculty Research & Creative Works

The pulse regulation control scheme is presented and applied to the boost integrated flyback rectifier/energy storage dc/dc (BIFRED) converter as the most popular member of the integrated high-quality rectifier-regulators (IHQRR). In contrast to the conventional control techniques, the principal idea of pulse regulation is to regulate the output voltage using a series of high- and low-power pulses generated by the current of the input inductor, which is operating in discontinuous conduction mode (DCM). Analysis of the BIFRED converter operating in DCM is presented. Fundamentals of pulse regulation as well as its stability analysis and the estimation of the output voltage …

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Reinforcement Learning-Based Output Feedback Control Of Nonlinear Systems With Input Constraints, Pingan He, Jagannathan Sarangapani Feb 2005

Reinforcement Learning-Based Output Feedback Control Of Nonlinear Systems With Input Constraints, Pingan He, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

A novel neural network (NN) -based output feedback controller with magnitude constraints is designed to deliver a desired tracking performance for a class of multi-input-multi-output (MIMO) discrete-time strict feedback nonlinear systems. Reinforcement learning in discrete time is proposed for the output feedback controller, which uses three NN: 1) a NN observer to estimate the system states with the input-output data; 2) a critic NN to approximate certain strategic utility function; and 3) an action NN to minimize both the strategic utility function and the unknown dynamics estimation errors. The magnitude constraints are manifested as saturation nonlinearities in the output feedback …

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A Graph-Based Model For Component-Based Software Development, Sahra Sedigh, Arif Ghafoor Feb 2005

A Graph-Based Model For Component-Based Software Development, Sahra Sedigh, Arif Ghafoor

Electrical and Computer Engineering Faculty Research & Creative Works

Software metrics can be used to objectively quantify the quality of software components and systems, alleviating quality and risk concerns and raising assurance in component-based systems. In this paper, we present a graph-based model for component-based software development. We assume that a number of components have been characterized in terms of non-functional metrics of importance to the software system being developed, and that the interfaces connecting various components have been similarly characterized. The emphasis of this work is on cost and quality of the system under development, and reaching an acceptable compromise between the two.

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Using A Neural Network To Distinguish Between The Contributions To Harmonic Pollution Of Non-Linear Loads And The Rest Of The Power System, Joy Mazumdar, Frank C. Lambert, Ganesh K. Venayagamoorthy, Ronald G. Harley Jan 2005

Using A Neural Network To Distinguish Between The Contributions To Harmonic Pollution Of Non-Linear Loads And The Rest Of The Power System, Joy Mazumdar, Frank C. Lambert, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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Optimal Control Parameters For A Upfc In A Multimachine Using Pso, Ganesh K. Venayagamoorthy Jan 2005

Optimal Control Parameters For A Upfc In A Multimachine Using Pso, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

The crucial factor affecting the modern power systems today is load flow control. The unified power flow controller (UPFC) is an effective means for controlling the power flow and can provide damping capability during transient conditions. The UPFC is controlled conventionally using PI controllers. The optimal design of the PI controllers for a UPFC is a challenging task and time consuming using the conventional techniques. This paper presents an approach using particle swarm optimization (PSO) for the design of optimal conventional controllers for a UPFC in a multimachine power system. Simulation results are presented to show the effectiveness of the …

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Shadow Detection By Combined Photometric Invariants For Improved Foreground Segmentation, Filiz Bunyak, Ilker Ersoy, S. R. Subramanya Jan 2005

Shadow Detection By Combined Photometric Invariants For Improved Foreground Segmentation, Filiz Bunyak, Ilker Ersoy, S. R. Subramanya

Electrical and Computer Engineering Faculty Research & Creative Works

Detection and tracking of moving objects are the essential steps of many video understanding applications such as traffic monitoring, video surveillance and visual event recognition. Moving object detection process segments the scene into foreground (moving) and background regions. Moving cast shadows cause serious problems in this process because they can easily be misclassified as foreground. This misclassification may lead to drastic changes in the shapes of objects or merging of multiple objects. in this paper, we present a method to detect moving cast shadows to improve the performance of moving object detection. the foreground regions are processed in terms of …

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A Warped Bandwidth Expansion Filter, Marc A. Boillot, John G. Harris Jan 2005

A Warped Bandwidth Expansion Filter, Marc A. Boillot, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

A warped filter is presented as a new speech enhancement method to adjust formant bandwidths on a critical band scale. The warped filter enhances perceived loudness without adding signal energy by exploiting the psychoacoustic nature of the auditory system. The critical band concept in auditory theory states that when the energy in a signal remains constant, loudness increases when the energy spreads beyond a critical bandwidth. A warped filter is proposed and developed to elevate the perceived loudness of clean speech by applying non-linear bandwidth expansion to the formant regions of vowels in accordance with the critical band scale. The …

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Estimation Of Additive Noise Variance For Multiuser Cdma Systems, Jingxian Wu, Chengshan Xiao, Khaled Ben Letaief Jan 2005

Estimation Of Additive Noise Variance For Multiuser Cdma Systems, Jingxian Wu, Chengshan Xiao, Khaled Ben Letaief

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel additive noise variance estimation algorithm is proposed for multiuser CDMA systems experiencing time varying and frequency selective fading. The algorithm is developed by exploring the eigen-structure of the receive signal correlation matrix, which is characterized by the statistid properties of both the fading channeI and the additive white Gaussian noise. Relying only on the knowledge of the receiver signal samples, the algorithm can accurately estimate the variance of the additive noise present at the receiver of multiuser CDMA systems. The estimated noise variance can be employed along with other receiver algorithms to improve system performance.

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Image Recognition Systems With Permutative Coding, Ernst M. Kussul, Donald C. Wunsch, Tatiana N. Baidyk Jan 2005

Image Recognition Systems With Permutative Coding, Ernst M. Kussul, Donald C. Wunsch, Tatiana N. Baidyk

Electrical and Computer Engineering Faculty Research & Creative Works

A feature extractor and neural classifier for image recognition system are proposed. They are based on the permutative coding technique which continues our investigations on neural networks. It permits us to obtain sufficiently general description of the image to be recognized. Different types of images were used to test the proposed image recognition system. It was tested on the handwritten digit recognition problem, the face recognition problem and the shape of microobjects recognition problem. The results of testing are very promising. The error rate for the MNIST database is 0.44% and for the ORL database is 0.1%.

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Infrastructure Roots: Evolution Of Electric Power In The United States, Mariesa Crow Jan 2005

Infrastructure Roots: Evolution Of Electric Power In The United States, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

Electricity holds a unique place in the US infrastructure. It is a commodity, a technology, and a necessity. Electric utilities must walk a fine line to balance each of these aspects. While electricity is a commodity that may be bought and sold, it must also be regulated to remain affordable for the general population. Reliability is continually balanced against the cost of upgrades and maintenance. This paper discusses the interconnection of regional area power systems in the US and the benefits such interconnection brings.

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Manpower Development: Industry And Educators Need To Work Together, Peter W. Sauer, Mani Venkata, Mariesa Crow Jan 2005

Manpower Development: Industry And Educators Need To Work Together, Peter W. Sauer, Mani Venkata, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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Neural Network -Based Nearly Optimal Hamilton-Jacobi-Bellman Solution For Affine Nonlinear Discrete-Time Systems, Jagannathan Sarangapani, Zheng Chen Jan 2005

Neural Network -Based Nearly Optimal Hamilton-Jacobi-Bellman Solution For Affine Nonlinear Discrete-Time Systems, Jagannathan Sarangapani, Zheng Chen

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we consider the use of nonlinear networks towards obtaining nearly optimal solutions to the control of nonlinear discrete-time systems. The method is based on least-squares successive approximation solution of the Generalized Hamilton-Jacobi-Bellman (HJB) equation. Since successive approximation using the GHJB has not been applied for nonlinear discrete-time systems, the proposed recursive method solves the GHJB equation in discrete-time on a well-defined region of attraction. The definition of GHJB, Pre-Hamiltonian function, HJB equation and method of updating the control function for the affine nonlinear discrete time systems are proposed. A neural network is used to approximate the GHJB …

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Neural Networks Based Non-Uniform Scalar Quantizer Design With Particle Swarm Optimization, Wenwei Zha, Ganesh K. Venayagamoorthy Jan 2005

Neural Networks Based Non-Uniform Scalar Quantizer Design With Particle Swarm Optimization, Wenwei Zha, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

Quantization is a crucial link in the process of digital speech communication. Non-uniform quantizer such as the logarithm quantizers are commonly used in practice. In this paper, a companding non-uniform quantizer is designed using two neural networks to perform the nonlinear transformation. Particle swarm optimization is applied to find the weights of neural networks such that the signal to noise ratio (SNR) is maximized. Simulation results on different speech samples are presented and the proposed quantizer design is compared with the logarithm quantizer for bit rates ranging from 3 to 8.

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Optimal Dynamic Neurocontrol Of A Gate-Controlled Series Capacitor In A Multi-Machine Power System, Swakshar Ray, Ganesh K. Venayagamoorthy, Edson H. Watanabe, F. D. De Jesus Jan 2005

Optimal Dynamic Neurocontrol Of A Gate-Controlled Series Capacitor In A Multi-Machine Power System, Swakshar Ray, Ganesh K. Venayagamoorthy, Edson H. Watanabe, F. D. De Jesus

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents the design of an optimal dynamic neurocontroller for a new type of FACTS device - the gate controlled series capacitor (GCSC) incorporated in a multi-machine power system. The optimal neurocontroller is developed based on the heuristic dynamic programming (HDP) approach. In addition, a dynamic identifier/model and controller structure using the recurrent neural network trained with backpropagation through time (BPTT) is employed. Simulation results are presented to show the effectiveness of the dynamic neurocontroller and its performance is compared with that of the conventional PI controller under small and large disturbances.

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Predictive Congestion Control Mac Protocol For Wireless Sensor Networks, Maciej Jan Zawodniok, Jagannathan Sarangapani Jan 2005

Predictive Congestion Control Mac Protocol For Wireless Sensor Networks, Maciej Jan Zawodniok, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

Available congestion control schemes, for example transport control protocol (TCP), when applied to wireless networks results in a large number of packet drops, unfairness with a significant amount of wasted energy due to retransmissions. To fully utilize the hop by hop feedback information, a suite of novel, decentralized, predictive congestion control schemes are proposed for wireless sensor networks in concert with distributed power control (DPC). Besides providing energy efficient solution, embedded channel estimator in DPC predicts the channel quality. By using the channel quality and node queue utilizations, the onset of network congestion is predicted and congestion control is initiated. …

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