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Electrical and Computer Engineering Faculty Research & Creative Works

2005

Articles 121 - 142 of 142

Full-Text Articles in Engineering

Influence Of Oxygen Microenvironment On Microfluidic Glucose Sensor Performance, Chang-Soo Kim, Jongwon Park Jan 2005

Influence Of Oxygen Microenvironment On Microfluidic Glucose Sensor Performance, Chang-Soo Kim, Jongwon Park

Electrical and Computer Engineering Faculty Research & Creative Works

We propose a novel method to overcome significant problems of baseline drift and sensitivity degradation in amperometric biosensors based on oxidase enzyme reactions. A novel glucose microsensor with a built-in electrochemical oxygen manipulation microsystem is introduced to demonstrate three novel functionalities; one-point in situ self-calibration (zero-point), broadening of dynamic range and increase in sensitivity. The influence of electrochemically generated oxygen microenvironment on the sensor output within a fluidic structure is investigated.

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A Comparison Of Pso And Backpropagation For Training Rbf Neural Networks For Identification Of A Power System With Statcom, Salman Mohagheghi, Ganesh K. Venayagamoorthy, Yamille Del Valle, Ronald G. Harley Jan 2005

A Comparison Of Pso And Backpropagation For Training Rbf Neural Networks For Identification Of A Power System With Statcom, Salman Mohagheghi, Ganesh K. Venayagamoorthy, Yamille Del Valle, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

Backpropagation algorithm is the most commonly used algorithm for training artificial neural networks. While being a straightforward procedure, it suffers from extensive computations, relatively slow convergence speed and possible divergence for certain conditions. The efficiency of this method as the training algorithm of a radial basis function neural network (RBFN) is compared with that of particle swarm optimization, for neural network based identification of a small power system with a static compensator. The comparison of the two methods is based on the convergence speed and robustness of each method.

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A New Test Setup And Method For The Calibration Of Current Clamps, David Pommerenke, Ramachandran Chundru, Sunitha Chandra Jan 2005

A New Test Setup And Method For The Calibration Of Current Clamps, David Pommerenke, Ramachandran Chundru, Sunitha Chandra

Electrical and Computer Engineering Faculty Research & Creative Works

Current probes are widely used to measure the common mode currents in electromagnetic compatibility (EMC) applications. Often, it is necessary to characterize the ratio of measured voltage to the common mode currents up to gigahertz (GHz) frequencies. Existing calibration methods for current probes suffer from the problem of not directly measuring the current within the current clamp. Instead they either reconstruct the current from measurements at other locations or they use assumptions regarding the geometry which allows them to use a current that is measured at a different location without applying a mathematical correction. For example, by maintaining a 50-Ω …

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A Novel Method Based On Neural Networks To Distinguish Between Load Harmonics And Source Harmonics In A Power System, Joy Mazumdar, Frank C. Lambert, Ganesh K. Venayagamoorthy, Ronald G. Harley Jan 2005

A Novel Method Based On Neural Networks To Distinguish Between Load Harmonics And Source Harmonics In A 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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Energy-Efficient Rate Adaptation Mac Protocol For Ad Hoc Wireless Networks, Maciej Jan Zawodniok, Jagannathan Sarangapani Jan 2005

Energy-Efficient Rate Adaptation Mac Protocol For Ad Hoc Wireless Networks, Maciej Jan Zawodniok, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

Resource constraints in ad hoc wireless networks require that they are energy efficient during both transmission and rate adaptation. In this paper, we propose a novel energy-efficient rate adaptation protocol that selects modulation schemes online to maximize throughput based on channel state while saving energy. This protocol uses the distributed power control (DPC) algorithm (M. Zawodniok et al., 2004) to accurately determine the necessary transmission power and to reduce the energy consumption. Additionally, the transmission rate is altered using energy efficiency as a constraint to meet the required throughput, which is estimated with queue fill ratio. Moreover, back-off scheme is …

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Esd Susceptibility Characterization Of An Eut By Using 3d Esd Scanning System, Kai Wang, Jayong Koo, Giorgi Muchaidze, David Pommerenke Jan 2005

Esd Susceptibility Characterization Of An Eut By Using 3d Esd Scanning System, Kai Wang, Jayong Koo, Giorgi Muchaidze, David Pommerenke

Electrical and Computer Engineering Faculty Research & Creative Works

Electrostatic discharges (ESD) can lead to soft-errors (e.g., bit-errors, wrong resets etc.) in digital electronics. The use of lower threshold voltages and faster I/O increases the sensitivity. In the analysis of ESD problems, an exact knowledge of the affected pins and nets is essential for an optimal solution. In this paper, a three dimensional ESD scanning system which has been developed to record the ESD susceptibility map for printed circuit board is presented and the mechanisms that the ESD event couples into the digital devices is studied. The ESD susceptibility of a fast CMOS EUT is characterized by generating the …

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Making The Graduate-Industry Connection, Mariesa Crow Jan 2005

Making The Graduate-Industry Connection, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

Many utilities are beginning to ramp up their recruiting and hiring efforts to attract bright young engineering graduates into the industry to replace the large numbers of engineers that have recently retired or will retire in the next few years. Unfortunately, the long drought in hiring brought on by the uncertainty of deregulation and the perspective that the industry is "old and conservative" has caused a mismatch in the interests of young engineers and the companies that want to hire them. in addition, the number of young people pursuing engineering degrees is decreasing as they become attracted to other lucrative …

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Adaptive Critic Designs For Optimal Control Of Power Systems, Ganesh K. Venayagamoorthy, Ronald G. Harley Jan 2005

Adaptive Critic Designs For Optimal Control Of Power Systems, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

The increasing complexity of the modern power grid highlights the need for advanced modeling and control techniques for effective control of excitation, turbine and flexible AC transmission systems (FACTS). The crucial factors affecting the modern power systems today is voltage and load flow control. Simulation studies in the PSCAD/EMTDC environment and realtime laboratory experimental studies carried out are described and the results show the successful control of the power system elements and the entire power system with adaptive and optimal neurocontrol schemes. Performances of the neurocontrollers are compared with the conventional PI controllers for damping under different operating conditions for …

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Analytical Model For The Rectangular Power-Ground Structure Including Radiation Loss, Ji Chen, Todd H. Hubing, Weimin Shi, R. L. Chen Jan 2005

Analytical Model For The Rectangular Power-Ground Structure Including Radiation Loss, Ji Chen, Todd H. Hubing, Weimin Shi, R. L. Chen

Electrical and Computer Engineering Faculty Research & Creative Works

An accurate analytical model to predict via coupling within rectangular power-return plane structures is developed. Loss mechanisms, including radiation loss, dielectric loss, and conductor loss, are considered in this model. The radiation loss is incorporated into a complex propagating wavenumber as an artificial loss mechanism. The quality factors associated with three loss mechanisms are calculated and compared. The effects of radiation loss on input impedances and reflection coefficients are investigated for both high-dielectric-loss and low-dielectric-loss printed circuit boards. Measurements are performed to validate the effectiveness of this model.

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Suitability Of Pulse Train Control Technique For Bifred Converter, Mehdi Ferdowsi, Ali Emadi, Mark Telefus, Anatoly Shteynberg Jan 2005

Suitability Of Pulse Train Control Technique For Bifred Converter, Mehdi Ferdowsi, Ali Emadi, Mark Telefus, Anatoly Shteynberg

Electrical and Computer Engineering Faculty Research & Creative Works

Pulse TrainTM control scheme is presented and applied to a boost integrated flyback rectifier/energy storage dc-dc (BIFRED) converter operating in discontinuous conduction mode (DCM), which avoids the light-load high-voltage stress problem. In contrast to the conventional control techniques, the principal idea of Pulse Train technique is to regulate the output voltage using a series of high and low energy pulses generated by the current of the inductor. The applicability of the proposed technique to both the input and magnetizing inductances of BIFRED converter is investigated. Analysis of BIFRED converter operating in DCM as well as the output voltage ripple …

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Simulation-Based Performance Modeling For War Fighter In Loop Minefield Detection System, Abhilash Rajagopal, Sanjeev Agarwal, Sreeram Ramakrishnan Jan 2005

Simulation-Based Performance Modeling For War Fighter In Loop Minefield Detection System, Abhilash Rajagopal, Sanjeev Agarwal, Sreeram Ramakrishnan

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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Trends In Process Control Systems Security, Ann K. Miller Jan 2005

Trends In Process Control Systems Security, Ann K. Miller

Electrical and Computer Engineering Faculty Research & Creative Works

The protection of critical infrastructure systems is a hotly debated topic. The very label "critical infrastructure" implies that these systems are important, and they are: they support our everyday lives, from the water and food in our homes to our physical and financial welfare. This article explores the recent evolution of programmable logic controllers (PCSs) and their environments, explains the need for improved security in these systems, and describes some of the emerging research areas that offer promise in PCS security.

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A Measure Of Robustness Against Multiple Kinds Of Perturbations, Shoukat Ali, Behdis Eslamnour Jan 2005

A Measure Of Robustness Against Multiple Kinds Of Perturbations, Shoukat Ali, Behdis Eslamnour

Electrical and Computer Engineering Faculty Research & Creative Works

Parallel and distributed heterogeneous computing systems may operate in an environment that undergoes unpredictable changes causing certain system performance features to degrade. Such systems need robustness to guarantee limited degradation despite fluctuations in the behavior of its component parts or environment. Our previous work in this area presented a method for generating a measure of robustness for a given system. However, the focus of that approach was on a scenario where all perturbations were of the same kind, e.g., all perturbations were in message sizes or computation times, but not both message sizes and computation times. This paper gives an …

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A Neural Network Based Optimal Wide Area Control Scheme For A Power System, Ganesh K. Venayagamoorthy, Swakshar Ray Jan 2005

A Neural Network Based Optimal Wide Area Control Scheme For A Power System, Ganesh K. Venayagamoorthy, Swakshar Ray

Electrical and Computer Engineering Faculty Research & Creative Works

With deregulation of the power industry, many tie lines between control areas are driven to operate near their maximum capacity, especially those serving heavy load centers. Wide area control systems (WACSs) using wide-area or global signals can provide remote auxiliary control signals to local controllers such as automatic voltage regulators, power system stabilizers, etc to damp out inter-area oscillations. This paper presents the design and the DSP implementation of a nonlinear optimal wide area controller based on adaptive critic designs and neural networks for a power system on the real-time digital simulator (RTDS©). The performance of the WACS as a …

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Emi Specifics Of Synchronous Dc-Dc Buck Converters, Zhe Li, David Pommerenke Jan 2005

Emi Specifics Of Synchronous Dc-Dc Buck Converters, Zhe Li, David Pommerenke

Electrical and Computer Engineering Faculty Research & Creative Works

DC-DC buck converter topology is widely used in computers and telecom applications because of its high power efficiency and multiple DC levels. However, EMI can be an issue because of its fast switching characteristics and large currents. This paper addresses the analysis of radiated EMI problems associated with DC-DC buck converters and evaluates the effectiveness of solutions that minimize the reverse recovery of the drain-bulk diode of the synchronous switching MOSFET.

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Decentralized Discrete-Time Neural Network Controller For A Class Of Nonlinear Systems With Unknown Interconnections, Jagannathan Sarangapani Jan 2005

Decentralized Discrete-Time Neural Network Controller For A Class Of Nonlinear Systems With Unknown Interconnections, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

A novel decentralized neural network (NN) controller in discrete-time is designed for a class of uncertain nonlinear discrete-time systems with unknown interconnections. Neural networks are used to approximate both the uncertain dynamics of the nonlinear systems and the unknown interconnections. Only local signals are needed for the decentralized controller design and the stability of the overall system can be guaranteed using the Lyapunov analysis. Further, controller redesign for the original subsystems is not required when additional subsystems are appended. Simulation results demonstrate the effectiveness of the proposed controller. The NN does not require an offline learning phase and the weights …

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Negative Reinforcement And Backtrack-Points For Recurrent Neural Networks For Cost-Based Abduction, Donald C. Wunsch, Ashraf M. Abdelbar, M. A. El-Hemaly, Emad A. M. Andrews Jan 2005

Negative Reinforcement And Backtrack-Points For Recurrent Neural Networks For Cost-Based Abduction, Donald C. Wunsch, Ashraf M. Abdelbar, M. A. El-Hemaly, Emad A. M. Andrews

Electrical and Computer Engineering Faculty Research & Creative Works

Abduction is the process of proceeding from data describing a set of observations or events, to a set of hypotheses which best explains or accounts for the data. Cost-based abduction (CKA) is an AI formalism in which evidence to be explained is treated as a goal to be proven, proofs have costs based on how much needs to be assumed to complete the proof, and the set of assumptions needed to complete the least-cost proof are taken as the best explanation for the given evidence. In this paper, we introduce two techniques for improving the performance of high order recurrent …

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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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Neural Network-Based Control Of Nonlinear Discrete-Time Systems In Non-Strict Form, Jagannathan Sarangapani, Zheng Chen, Pingan He Jan 2005

Neural Network-Based Control Of Nonlinear Discrete-Time Systems In Non-Strict Form, Jagannathan Sarangapani, Zheng Chen, Pingan He

Electrical and Computer Engineering Faculty Research & Creative Works

A novel reinforcement learning-based adaptive neural network (NN) controller, also referred as the adaptive-critic NN controller, is developed to deliver a desired tracking performance for a class of non-strict feedback nonlinear discrete-time systems in the presence of bounded and unknown disturbances. The adaptive critic NN controller architecture includes a critic NN and two action NNs. The critic NN approximates certain strategic utility function whereas the action neural networks are used to minimize both the strategic utility function and the unknown dynamics estimation errors. The NN weights are tuned online so as to minimize certain performance index. By using gradient descent-based …

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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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Power System Optimization And Coordination Of Damping Controls By Series Facts Devices, Jung-Wook Park, Ganesh K. Venayagamoorthy, Ronald G. Harley Jan 2005

Power System Optimization And Coordination Of Damping Controls By Series Facts Devices, Jung-Wook Park, 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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