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Electrical and Computer Engineering Faculty Research & Creative Works

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Articles 2191 - 2220 of 3518

Full-Text Articles in Engineering

Comparison Of Focused And Near-Field Imaging Of Spray On Foam Insulation (Sofi) At Millimeter Wave Frequencies, Sergey Kharkovsky, R. Zoughi, Frank L. Hepburn Jun 2007

Comparison Of Focused And Near-Field Imaging Of Spray On Foam Insulation (Sofi) At Millimeter Wave Frequencies, Sergey Kharkovsky, R. Zoughi, Frank L. Hepburn

Electrical and Computer Engineering Faculty Research & Creative Works

Millimeter wave imaging techniques can provide high spatial-resolution images of various composites. Lens antennas may be incorporated into the imaging system to provide a small incident beam footprint. Another approach may involve the use of horn antennas, which if operating in their near-fields, images with reasonably high spatial-resolutions may also be obtained. This paper gives a comparison between such near-field and focused far-field imaging of the Space Shuttle Spray on Foam Insulation (SOFI) used in its external fuel tank at millimeter wave frequencies. Small horn antennas and lens antennas with relatively long depth of focus were used in this investigation.

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Dynamic Modeling Of Wind Farms With Fixed-Speed Wind Turbine Generators, Wei Qiao, Ronald G. Harley, Ganesh K. Venayagamoorthy Jun 2007

Dynamic Modeling Of Wind Farms With Fixed-Speed Wind Turbine Generators, Wei Qiao, Ronald G. Harley, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

A wind farm typically consists of a large number of individual wind turbine generators (WTGs) connected by an internal electrical network. To study the impact of wind farms on the dynamics of the power system, an important issue is to develop appropriate wind farm models to represent the dynamics of many individual WTGs. This paper presents various dynamic models, including a detailed model and three reduced-order equivalent models, of wind farms with fixed-speed WTGs. These models are developed and compared by simulation studies in the PSCAD/EMTDC environment under different wind velocity and fluctuation conditions as well as gird fault conditions. …

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Impedance Identification Of Integrated Power System Components Using Recurrent Neural Networks., Peng Xiao, Ganesh K. Venayagamoorthy, Keith Corzine May 2007

Impedance Identification Of Integrated Power System Components Using Recurrent Neural Networks., Peng Xiao, Ganesh K. Venayagamoorthy, Keith Corzine

Electrical and Computer Engineering Faculty Research & Creative Works

Impedance characteristics of shipboard power systems provide important information for studies on system stability and integration. Existing injection based impedance measurement techniques require multiple tests on the system to obtain characteristics over wide frequency ranges. In this paper, recurrent neural networks (RNNs) are used to model the small signal dynamics of power electronic systems based on a single test in which randomized signals are injected into the system. The trained RNN is then used to extract the small-signal impedances/admittances of the system. A number of tests have been carried out in simulation to verify the effectiveness of the proposed method.

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Bist Design For Ccd Based Digital Imaging System, Bin Jin, Nohpill Park, Serge N. Demidenko, Minsu Choi, Fabrizio Lombardi May 2007

Bist Design For Ccd Based Digital Imaging System, Bin Jin, Nohpill Park, Serge N. Demidenko, Minsu Choi, Fabrizio Lombardi

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a BIST design for CCD-based digital imaging system. Pixels on a CCD are not free from defective or faulty pixels due to numerous causes such as imperfect fabrication, excessive exposure to light, radiation, sensing element aging, and excessive mechanical shock, to mention a few. Today's high demand for high resolution CCDs is dictating defect/fault-tolerance in such devices. Especially, traditional on-device BIST cannot be readily employed on the imaging devices such as CCD due to the unique requirement that no pixel can be utilized to repair or bypass a defect on any other pixels. Therefore, the BIST technique …

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High Resolution Millimeter Wave Inspecting Of The Orbiter Acreage Heat Tiles Of The Space Shuttle, Joseph Toby Case, Sergey Kharkovsky, R. Zoughi, Frank L. Hepburn May 2007

High Resolution Millimeter Wave Inspecting Of The Orbiter Acreage Heat Tiles Of The Space Shuttle, Joseph Toby Case, Sergey Kharkovsky, R. Zoughi, Frank L. Hepburn

Electrical and Computer Engineering Faculty Research & Creative Works

The physical cause of Space Shuttle Columbia's catastrophic failure was a breach in its thermal protection system, caused by a piece of external tank insulating foam (SOFI) separating from the external tank and striking the leading edge of the left wing of the orbiter. Consequently, there is an urgent need for a rapid, robust and life-circle oriented nondestructive testing (NDT) technique capable of inspecting the SOFI as well as the orbiter's protective heat tiles and its fuselage prior and subsequent to a launch. Microwave and millimeter wave NDT methods have shown great potential to achieve these goals using real focused …

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Single-Phase Ac Impedance Modeling For Stability Of Integrated Power Systems, Jing Huang, Keith Corzine, M. Belkhayat May 2007

Single-Phase Ac Impedance Modeling For Stability Of Integrated Power Systems, Jing Huang, Keith Corzine, M. Belkhayat

Electrical and Computer Engineering Faculty Research & Creative Works

To date, the only power system stability requirement that can be decomposed or quantitatively "flowed" down to component design requirements are impedance based. Impedance based requirements have been advanced for both dc and three-phase ac but none for single-phase ac interfaces. What are ultimately needed are universal stability requirements that are applicable to dc, single-phase ac, and three-phase ac interfaces as well as a measurement tool which can be used to enforce the requirements at all interfaces without changing the fundamental structure of the impedance measurement device. These advanced techniques should be applicable to all voltage levels currently in use …

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Accurate Macro-Modeling For Leakage Current For IDdq Test, Kyung Ki Kim, Yong-Bin Kim, Minsu Choi, Nohpill Park May 2007

Accurate Macro-Modeling For Leakage Current For IDdq Test, Kyung Ki Kim, Yong-Bin Kim, Minsu Choi, Nohpill Park

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes a new precise macro-modeling for leakage current in BSIM4 65nm technology considering subthreshold leakage, gate tunneling leakage, stack effect, and fanout effect. Using the accurate macro-model, a heuristic algorithm is developed to estimate the leakage power and generate input test pattern for minimum leakage. The algorithm applies to ISCAS85 benchmark circuits, and the results are compared with the results of Hspice. The experimental result shows that the leakage power estimation using our macro-model is within 5% difference when comparing to Hspice results.

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The Use Of Accelerated Full-Wave Modeling To Analyze Power Island Coupling In A Hyperbga Scm, Jason Morsey, Alina Deutsch, J. P. Libous, C. Surovic, Barry J. Rubin, Lijun Jiang, L. Eisenberg May 2007

The Use Of Accelerated Full-Wave Modeling To Analyze Power Island Coupling In A Hyperbga Scm, Jason Morsey, Alina Deutsch, J. P. Libous, C. Surovic, Barry J. Rubin, Lijun Jiang, L. Eisenberg

Electrical and Computer Engineering Faculty Research & Creative Works

Presented here are results and recommendations for reducing coupling between adjacent power islands based on full-wave simulations of a HyperBGA SCM (single-chip module). These simulations highlight the use of IBM's internally developed accelerated full-wave solver based on the precorrected fast Fourier transform approach. Speedups of 100 x and memory reductions of 12 x are shown for real engineering problems, as compared to direct integral equation solutions. © 2007 IEEE.

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Variable Regularized Fast Affine Projections, Steven L. Grant, Asif Iqbal Mohammad, Deepak Challa Apr 2007

Variable Regularized Fast Affine Projections, Steven L. Grant, Asif Iqbal Mohammad, Deepak Challa

Electrical and Computer Engineering Faculty Research & Creative Works

This paper introduces a variable regularization method for the fast affine projection algorithm (VR-FAP). It is inspired by a recently introduced technique for variable regularization of the classical, affine projection algorithm (VR-APA). In both algorithms, the regularization parameter varies as a function of the excitation, measurement noise, and residual error energies. Because of the dependence on the last parameter, VR-APA and VR-FAP demonstrate the desirable property of fast convergence (via a small regularization value) when the convergence is poor and deep convergence/immunity to measurement noise (via a large regularization value) when the convergence is good. While the regularization parameter of …

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Implementation Of Static And Semi-Static Versions Of A 24+8x8 Quad-Rail Null Convention Multiply And Accumulate Unit, R. Sankar, V. Kadiyala, S. Kumar, S. Mohan, F. Kacani, Waleed K. Al-Assadi, Scott C. Smith, Ravi Bonam Apr 2007

Implementation Of Static And Semi-Static Versions Of A 24+8x8 Quad-Rail Null Convention Multiply And Accumulate Unit, R. Sankar, V. Kadiyala, S. Kumar, S. Mohan, F. Kacani, Waleed K. Al-Assadi, Scott C. Smith, Ravi Bonam

Electrical and Computer Engineering Faculty Research & Creative Works

This paper focuses on implementing a 2s complement 8x8 dual-rail bit-wise pipelined multiplier using the asynchronous null convention logic (NCL) paradigm. The design utilizes a Wallace tree for partial product summation, and is implemented and simulated in VHDL, the transistor level, and the physical level, using a 1.8V 0.18mum TSMC CMOS process. The multiplier is realized using both static and semi-static versions of the NCL gates; and these two implementations are compared in terms of area, power, and speed.

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Impact-Induced Damage Characterization Of Composite Plates Using Neural Networks, Steve Eugene Watkins, Farhad Akhavan, Rohit Dua, K. Chandrashekhara, Donald C. Wunsch Apr 2007

Impact-Induced Damage Characterization Of Composite Plates Using Neural Networks, Steve Eugene Watkins, Farhad Akhavan, Rohit Dua, K. Chandrashekhara, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

Impact-induced damage in fiber-reinforced laminated composite plates is characterized. An instrumented impact tower was used to carry out low-velocity impacts on thirteen clamped glass/epoxy composite plates. A range of impact energies was experimentally investigated by progressively varying impactor masses (holding the impact height constant) and varying impact heights (holding the impactor mass constant). The in-plane strain profiles as measured by polyvinylidene fluoride (PVDF) piezoelectric sensors are shown to indicate damage initiation and to correlate to impact energy. Plate damage included matrix cracking, fiber breakage, and delamination. Electronic shearography validated the existence of the impact damage and demonstrated an actual damage …

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Application Of Neural Networks For Data Modeling Of Power Systems With Time Varying Nonlinear Loads, Joy Mazumdar, Ganesh K. Venayagamoorthy, Ronald G. Harley Apr 2007

Application Of Neural Networks For Data Modeling Of Power Systems With Time Varying Nonlinear Loads, Joy Mazumdar, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

Nowadays power distribution systems typically operate with nonsinusoidal voltages and currents. Harmonic currents from nonlinear loads propagate through the system and cause harmonic pollution. The premise of IEEE 519 is that there exists a shared responsibility between utilities and customers regarding harmonic control. Maintaining reasonable levels of harmonic voltage distortion depends upon customers limiting their harmonic current injections and utilities controlling the system impedance characteristics. Measurements of current taken at the point of common coupling (PCC) to a customer are expected to determine whether the customer is in compliance with IEEE 519. These measurements yield the combination of nonlinear load …

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Teaching Asynchronous Digital Design In The Undergraduate Computer Engineering Curriculum, Scott C. Smith, Waleed K. Al-Assadi Apr 2007

Teaching Asynchronous Digital Design In The Undergraduate Computer Engineering Curriculum, Scott C. Smith, Waleed K. Al-Assadi

Electrical and Computer Engineering Faculty Research & Creative Works

As demand continues for circuits with higher performance, higher complexity, and decreased feature size, asynchronous (clockless) paradigms will become more widely used in the semiconductor industry, as evidenced by the International Technology Roadmap for Semiconductors' (ITRS) prediction of a likely shift from synchronous to asynchronous design styles in order to increase circuit robustness, decrease power, and alleviate many clock-related issues. ITRS predicts that asynchronous circuits will account for 19% of chip area within the next 5 years, and 30% of chip area within the next 10 years. To meet this growing industry need, students in Computer Engineering should be introduced …

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Combined Training Of Recurrent Neural Networks With Particle Swarm Optimization And Backpropagation Algorithms For Impedance Identification, Peng Xiao, Ganesh K. Venayagamoorthy, Keith Corzine Apr 2007

Combined Training Of Recurrent Neural Networks With Particle Swarm Optimization And Backpropagation Algorithms For Impedance Identification, Peng Xiao, Ganesh K. Venayagamoorthy, Keith Corzine

Electrical and Computer Engineering Faculty Research & Creative Works

A recurrent neural network (RNN) trained with a combination of particle swarm optimization (PSO) and backpropagation (BP) algorithms is proposed in this paper. The network is used as a dynamic system modeling tool to identify the frequency-dependent impedances of power electronic systems such as rectifiers, inverters, and DC-DC converters. As a category of supervised learning methods, the various backpropagation training algorithms developed for recurrent neural networks use gradient descent information to guide their search for optimal weights solutions that minimize the output errors. While they prove to be very robust and effective in training many types of network structures, they …

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A Novel Normalized Cross-Correlation Based Echo-Path Change Detector, M. A. Izbal, Steven L. Grant Apr 2007

A Novel Normalized Cross-Correlation Based Echo-Path Change Detector, M. A. Izbal, Steven L. Grant

Electrical and Computer Engineering Faculty Research & Creative Works

A double-talk detector is used to freeze acoustic echo canceller's (AEC) filter adaptation during periods of near-end speech. Increased sensitivity towards double-talk results in declaring echo-path changes as double-talk which adversely effects the performance of an AEC as we freeze adaptation when we really need to adapt. Thus, we need an efficient and simple echo-path change detector so as to differentiate any echo-path variations from double-talk condition. In this paper, we derive a novel test statistic for echo-path change detection. The proposed decision statistic detects any echo-path variations, is normalized properly and is computationally very efficient as compared to existing …

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Nanofabric Pla Architecture With Double Variable Redundancy, Mandar V. Joshi, Waleed K. Al-Assadi Apr 2007

Nanofabric Pla Architecture With Double Variable Redundancy, Mandar V. Joshi, Waleed K. Al-Assadi

Electrical and Computer Engineering Faculty Research & Creative Works

It has been shown that fundamental electronic structures such as Diodes, and FET's can be constructed using selectively doped semiconducting carbon nanotubes or silicon nanowires (CNT's, SiNW's) at nanometer scale. Memory and Logic cores using these technologies have been proposed, that use the configurable junctions in two-dimensional crossbars of CNT's. These memories and logic arrays at this scale exhibit significant amount of defects that account for poor yield. Configuration of these devices in presence of defects demands for an overhead in terms of area and programming time. In this work, we introduce a PLA (programmable logic array) configuration that makes …

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A Framework For The Detection Of Crosstalk Noise In Fpgas, Sindhu Kakarla, Waleed K. Al-Assadi Apr 2007

A Framework For The Detection Of Crosstalk Noise In Fpgas, Sindhu Kakarla, Waleed K. Al-Assadi

Electrical and Computer Engineering Faculty Research & Creative Works

In recent years, crosstalk noise has emerged a serious problem because more and more devices and wires have been packed on electronic chips. As integrated circuits are migrated to more advanced technologies, it has become clear that crosstalk noise is the important phenomenon that must be taken into account. Despite of being more immune to crosstalk noise than their ASIC (application specific integrated circuit) counterparts, the dense interconnected structures of FPGAs (field programmable gate arrays) invite more vulnerabilities with crosstalk noise. Due to the lack of electrical detail concerning FPGA devices it is quite difficult to test the faults affected …

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A Fuzzy-Pso Based Controller For A Grid Independent Photovoltaic System, Richard L. Welch, Ganesh K. Venayagamoorthy Apr 2007

A Fuzzy-Pso Based Controller For A Grid Independent Photovoltaic System, Richard L. Welch, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a particle swarm optimization (PSO) method for optimizing a fuzzy logic controller (FLC) for a photovoltaic (PV) grid independent system consisting of a PV collector array, a storage battery, and loads (critical and non-critical loads). PSO is used to optimize both the membership functions and the rule set in the design of the FLC. Optimizing the PV system controller yields improved performance, allowing the system to meet more of the loads and keep a higher average state of battery charge. Potential benefits of an optimized controller include lower costs through smaller system sizing and a longer battery …

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Microwave And Millimeter Wave Nondestructive Testing And Evaluation -- Overview And Recent Advances, Sergey Kharkovsky, R. Zoughi Apr 2007

Microwave And Millimeter Wave Nondestructive Testing And Evaluation -- Overview And Recent Advances, Sergey Kharkovsky, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

This article focuses on three recent applications of microwave and millimeter wave NDT&E techniques that involve novel instrumentation development and measurements, including: 1) disbond detection in strengthened concrete bridge members retrofitted with carbon fiber reinforced polymer (CFRP) composite laminates; 2) corrosion and precursor pitting detection in painted aluminum and steel substrates; and 3) detection of flaws in spray-on foam insulation and the acreage heat tiles of the Space Shuttle through focused and synthetic imaging techniques. These applications have been performed at the Applied Microwave Nondestructive Testing Laboratory (amntl) at the University of Missouri-Rolla.

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Ncl Implementation Of Dual-Rail 2S Complement 8x8 Booth2 Multiplier Using Static And Semi-Static Primitives, Mandar V. Joshi, Sagar R. Gosavi, V. Jegadeesan, A. Basu, S. Jaiswal, Waleed K. Al-Assadi, Scott C. Smith Apr 2007

Ncl Implementation Of Dual-Rail 2S Complement 8x8 Booth2 Multiplier Using Static And Semi-Static Primitives, Mandar V. Joshi, Sagar R. Gosavi, V. Jegadeesan, A. Basu, S. Jaiswal, Waleed K. Al-Assadi, Scott C. Smith

Electrical and Computer Engineering Faculty Research & Creative Works

In this work, we use static and semi-static versions of NULL Convention Logic (NCL) primitives (i.e., threshold gates) to implement a dual-rail 8times8 2s complement multiplier using the Modified Booth2 algorithm for partial product generation and a Wallace tree for partial product summation. We establish the multiplier's functionality utilizing VHDL-based simulations of the gate-level structural design. The design is then implemented at the transistor-level and layout-level using both static and semi-static threshold gates, for a 1.8V 0.18mum TSMC CMOS process; and these two implementations are compared in terms of area, power, and speed.

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Automatic Speech Recognition Using A Predictive Echo State Network Classifier, Mark D. Skowronski, John G. Harris Apr 2007

Automatic Speech Recognition Using A Predictive Echo State Network Classifier, Mark D. Skowronski, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

We have combined an echo state network (ESN) with a competitive state machine framework to create a classification engine called the predictive ESN classifier. We derive the expressions for training the predictive ESN classifier and show that the model was significantly more noise robust compared to a hidden Markov model in noisy speech classification experiments by 8±1 dB signal-to-noise ratio. The simple training algorithm and noise robustness of the predictive ESN classifier make it an attractive classification engine for automatic speech recognition. © 2007 Elsevier Ltd. All rights reserved.

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Adaptive Power System Stabilizers Using Artificial Immune System, Ganesh K. Venayagamoorthy, Mani Hunjan Apr 2007

Adaptive Power System Stabilizers Using Artificial Immune System, Ganesh K. Venayagamoorthy, Mani Hunjan

Electrical and Computer Engineering Faculty Research & Creative Works

Power system stabilizers (PSSs) are used to damp intra-area and inter-area oscillations in a power network. They provide effective supplementary control by supplying auxiliary control signals to the excitation system of the generators. The proper tuning of PSSs has a significant influence on its effectiveness in providing the required damping under different operating conditions and disturbances. Various algorithms have been successfully implemented to simultaneously design multiple optimal PSSs in power systems. As the power network's operating conditions change, the performance of PSSs degrade. Optimal PSS parameters obtained using bacteria foraging algorithm (BFA) have shown to successfully damp out system oscillations …

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Method And Apparatus For Nondestructive Sample Inspection, R. Zoughi, Sergey Kharkovsky, Mohammad Tayeb Ahmad Ghasr Mar 2007

Method And Apparatus For Nondestructive Sample Inspection, R. Zoughi, Sergey Kharkovsky, Mohammad Tayeb Ahmad Ghasr

Electrical and Computer Engineering Faculty Research & Creative Works

An apparatus for inspecting a sample for defects includes a signal generator for generating a signal and a device for splitting the signal into two separate signals which have substantially equal phase and magnitude. A sensor radiates the two signals on the sample and receives the two signals reflected from the sample. A device is provided for determining a difference between the two signals reflected from the sample without unwanted influence of variations of distance between the sensor and sample, and reflections from nearby sample edges and boundaries. A defect is determined to exist when a difference is found between …

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On The Error Performance Of Wireless Systems With Frequency Selective Fading And Receiver Timing Phase Offset, Jingxian Wu, Y. Rosa Zheng, Khaled Ben Letaief, Chengshan Xiao Jan 2007

On The Error Performance Of Wireless Systems With Frequency Selective Fading And Receiver Timing Phase Offset, Jingxian Wu, Y. Rosa Zheng, Khaled Ben Letaief, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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Sofc-Based Fuel Cells For Load Following Stationary Applications, Nagasmitha Akkinapragada, Badrul H. Chowdhury Jan 2007

Sofc-Based Fuel Cells For Load Following Stationary Applications, Nagasmitha Akkinapragada, Badrul H. Chowdhury

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a dynamic model of SOFC and the response of the fuel cell for sudden load changes. Slow response of the fuel cell prevents it from following the load, Hence connection with the DC/DC buck-boost converter is required. The models are developed in PSCAD with and without a feedback control system. Power characteristics obtained in order to validate the need of the DC/DC converter which allows the SOFC system to be used for load following applications

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Noise-Robust Automatic Speech Recognition Using A Discriminative Echo State Network, Mark D. Skowronski, John G. Harris Jan 2007

Noise-Robust Automatic Speech Recognition Using A Discriminative Echo State Network, Mark D. Skowronski, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

The echo state network (ESN) is a recurrent neural network proposed by Herbert Jaeger with a simplified training routine. Previously, we have demonstrated the noise-robust performance of the predictive ESN classifier in automatic speech recognition experiments in which the network was trained to predict the next frame of speech features. Classification performance was limited because the predictive models lacked discriminability, so we changed the model output to a one-of-many output encodings scheme and trained the model discriminatively. Performance was compared to a hidden Markov model (HMM) in small-vocabulary ASR experiments with additive noise. Accuracy of 50% was achieved by a …

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Experimental Investigation Of The Esd Sensitivity Of An 8-Bit Microcontroller, Lijun Han, Jayong Koo, David Pommerenke, Daryl G. Beetner, Ross Carlton Jan 2007

Experimental Investigation Of The Esd Sensitivity Of An 8-Bit Microcontroller, Lijun Han, Jayong Koo, David Pommerenke, Daryl G. Beetner, Ross Carlton

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, the susceptibility of an 8-bit microcontroller to electrostatic discharge (ESD) and electrically fast transients was tested by injecting currents through a capacitive probe into the microcontroller package pins. The reaction of the microcontroller to discharges with different rise times and polarities were investigated by measuring the voltage on the tested pins and by observing the microcontroller's clock output. Susceptibility varied significantly when injecting to one pin compared to another. Interestingly, the clock was more sensitive to currents injected into I/O pins than into pins directly related to the clock (e. g. EXTAL). Further work is underway to …

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Frequency-Domain Channel Estimation And Equalization For Single Carrier Underwater Acoustic Communications, Y. Rosa Zheng, Chengshan Xiao, T. C. Yang, Wen-Bin Yang Jan 2007

Frequency-Domain Channel Estimation And Equalization For Single Carrier Underwater Acoustic Communications, Y. Rosa Zheng, Chengshan Xiao, T. C. Yang, Wen-Bin Yang

Electrical and Computer Engineering Faculty Research & Creative Works

A new frequency-domain channel estimation and equalization (FDE) scheme is proposed for single carrier (SC) underwater acoustic communications. The proposed SC-FDE employs a small training signal block for initial channel estimation in the frequency domain and converts the estimated transfer function to a desired DFT (discrete Fourier transform) size for channel equalization of the data blocks. The frequency domain equalizer is designed using the linear minimum mean square error criterion. A new phase coherent detection scheme is also proposed and deployed to combat the phase drift due to the instantaneous Doppler in the underwater channels. The channel transfer functions and …

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Health Monitoring Of A Truss Bridge Using Adaptive Identification, James W. Fonda, Steve Eugene Watkins Jan 2007

Health Monitoring Of A Truss Bridge Using Adaptive Identification, James W. Fonda, Steve Eugene Watkins

Electrical and Computer Engineering Faculty Research & Creative Works

Integration of structural analysis, system identification, and sensor networks provide health monitoring capabilities that benefit many aspects of infrastructure management. This work presents an adaptive identification method based on Lyapunov methods for a truss structure. Lyapunov methods in the identification provide guaranteed convergence for the parameter estimation. Identification is carried out on a simulation model based on FEA methods. The FEA model offers realistic results from a truss structure and allows verification of the identification method for a rolling load case. A rolling load scenario provides use of realistic loading of a structure so that identification methods may be extended …

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Implementation Of A Converter In Sequence Domain To Counter Voltage Imbalances, Murali M. Baggu, Badrul H. Chowdhury Jan 2007

Implementation Of A Converter In Sequence Domain To Counter Voltage Imbalances, Murali M. Baggu, Badrul H. Chowdhury

Electrical and Computer Engineering Faculty Research & Creative Works

This paper demonstrates the basic problem of the conventional d-axis and q-axis control applied to a voltage source converter (VSC) during a system imbalance. The specific imbalances studied are a balanced fault and an unbalanced fault at the terminals of the converter. The dc link voltage of the VSC is disturbed during the unbalanced fault due to negative sequence components in the system. The sequence characteristics of the system during an imbalance are further analyzed. A novel controller in the sequence domain is proposed. The positive sequence components of the control are implemented in the positive synchronous reference frame and …

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