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Electrical and Computer Engineering Faculty Research & Creative Works

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Articles 2731 - 2760 of 3518

Full-Text Articles in Engineering

Adaptive Critics For Dynamic Particle Swarm Optimization, Ganesh K. Venayagamoorthy Jan 2004

Adaptive Critics For Dynamic Particle Swarm Optimization, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

This work introduces a novel technique for dynamic particle swarm optimization (DPSO) using adaptive critic designs. The adaptation between global and local search in an optimization algorithm is critical for optimization problems especially in a dynamically changing environment or process over time. The inertia weight in particle swarm optimization (PSO) is dynamically adjusted in this paper in order to provide a nonlinear search capability for the PSO algorithm. Results on benchmark functions in the literature are provided.

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Power Flow And Stability Models For Induction Generators Used In Wind Turbines, Kiran K. Nandigam, Badrul H. Chowdhury Jan 2004

Power Flow And Stability Models For Induction Generators Used In Wind Turbines, Kiran K. Nandigam, Badrul H. Chowdhury

Electrical and Computer Engineering Faculty Research & Creative Works

Model initialization of the induction generator for the wind power generation is investigated. Incorrect initialization may lead to numerical instability problems, not to mention erroneous result from dynamic simulation. The machine model is studied from the perspective of slip and reactive power calculation and tested for various cases. The dynamic reactive power calculation in well-know software package is discussed and the deviation of dynamic reactive power from the steady state reactive power is highlighted.

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Partial Discharge On-Line Monitoring For Hv Cable Systems Using Electrooptic Modulators, Paul L. Lewin, David Pommerenke, Simon J. Sutton, Yuan Tian, James S. Wilkinson Jan 2004

Partial Discharge On-Line Monitoring For Hv Cable Systems Using Electrooptic Modulators, Paul L. Lewin, David Pommerenke, Simon J. Sutton, Yuan Tian, James S. Wilkinson

Electrical and Computer Engineering Faculty Research & Creative Works

A technique for the remote inspection and monitoring of partial discharge (PD) activity using an optical network is described. The network uses a LiNbO3, modulator to modulate the intensity of the transmitted laser light approximately proportional to the voltage applied across the modulator. The laser light is transmitted along an optical fibre and measured remotely by a high-speed optical receiver. A capacitive coupler has been used to detect partial discharge activity and act as the modulator's input voltage source. The electro-optic modulator is passive and does not require a power supply at the site of the PD detection sensor. The …

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A Method For Enhancing The Snapshot Performance In San Volume Manager, Chang-Soo Kim, Dong-Jae Kang, Young-Ho Kim, Hag-Young Kim, Myoung-Jun Kim, Yu-Hyeon Bak Jan 2004

A Method For Enhancing The Snapshot Performance In San Volume Manager, Chang-Soo Kim, Dong-Jae Kang, Young-Ho Kim, Hag-Young Kim, Myoung-Jun Kim, Yu-Hyeon Bak

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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A New Estimative Current Mode Control Technique For Dc-Dc Converters Operating In Discontinuous Conduction Mode, Mehdi Ferdowsi, Zhong Nie, Ali Emadi Jan 2004

A New Estimative Current Mode Control Technique For Dc-Dc Converters Operating In Discontinuous Conduction Mode, Mehdi Ferdowsi, Zhong Nie, Ali Emadi

Electrical and Computer Engineering Faculty Research & Creative Works

A new digital control technique for power converters operating in discontinuous conduction mode (DCM) is introduced and applied to a boost converter. In contrast to the conventional analogue control methods, the principal idea of this new control scheme is to use real-time analysis and estimate the required on-time of the switch based on the dynamic of the system. The proposed control algorithm can easily be programmed in a digital signal processor (DSP). This novel technique is applicable to any converter operating in DCM including power factor correctors (PFC). However, this work mainly focuses on the boost topology. In this paper, …

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An Engineering Primer For Outreach To K-4 Education, Theresa M. Swift, Steve Eugene Watkins Jan 2004

An Engineering Primer For Outreach To K-4 Education, Theresa M. Swift, Steve Eugene Watkins

Electrical and Computer Engineering Faculty Research & Creative Works

Student motivation for and proficiency in science and mathematics begin in the early grades. Level-appropriate resources and professional outreach activities are as beneficial for teachers and students at elementary levels as for higher levels. Engineering applications can be effective vehicles for giving students hands-on exposure to technical concepts and for showing students how these concepts relate to everyday life. To improve the technical literacy of society and to promote STEM-related careers, engineers should be engaged in active outreach. However, engineers who seek these types of projects have some learning to do themselves. They must understand the unique elementary education environment …

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Position Sensorless Control, Babak Fahimi, Ali Emadi, Raymond B. Sepe Jan 2004

Position Sensorless Control, Babak Fahimi, Ali Emadi, Raymond B. Sepe

Electrical and Computer Engineering Faculty Research & Creative Works

The switched reluctance machines (SRM) drives applications are studied. the introduction of SRM drives in mission critical applications calls for high levels of survivability and fault tolerance. the various methods are proposed for the sensor less control of SRM drives. the best version of the sensor less technique is selected by continuous monitoring of the back-EMF. the results show that four-quadrant sensor less control of the SRM drive is a feasible technique and can be considered as a technology ready for application.

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Modeling And Analysis Of Soft-Test/Repair For Ccd-Based Digital X-Ray Systems, Byoungjae Jin, Nohpill Park, Koshy M. George, Minsu Choi, Mark B. Yeary Dec 2003

Modeling And Analysis Of Soft-Test/Repair For Ccd-Based Digital X-Ray Systems, Byoungjae Jin, Nohpill Park, Koshy M. George, Minsu Choi, Mark B. Yeary

Electrical and Computer Engineering Faculty Research & Creative Works

Modern X-ray imaging systems evolve toward digitization for reduced cost, faster time-to-diagnosis, and improved diagnostic confidence. For the digital X-ray systems, charge coupled device (CCD) technology is commonly used to detect and digitize optical X-ray image. This paper presents a novel soft-test/repair approach to overcome the defective pixel problem in CCD-based digital X-ray systems through theoretical modeling and analysis of the test/repair process. There are two possible solutions to cope with the defective pixel problem in CCDs: one is the hard-repair approach and another is the proposed soft-test/repair approach. Hard-repair approach employs a high-yield, expensive reparable CCD to minimize the …

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Design And Characterization Of Null Convention Self-Timed Multipliers, Satish K. Bandapati, Scott C. Smith, Minsu Choi Nov 2003

Design And Characterization Of Null Convention Self-Timed Multipliers, Satish K. Bandapati, Scott C. Smith, Minsu Choi

Electrical and Computer Engineering Faculty Research & Creative Works

Self-timed multipliers, designed using the delay-insensitive null convention logic (NCL) paradigm, were analyzed. NCL require less power, generate less noise, produce less electromagnetic interference, and allow easier reuse of components. Simulation results show a large variance in circuit performance in terms of power, area, and speed. NCL paradigm also represent bit-serial, iterative, and fully parallel multiplication architectures. They reduce the effort required to ensure correct operation under all timing scenarios, compared to equivalent synchronous designs.

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A Four-Level Crossing Dc/Dc Converter Based Drive System, X. Kou, Keith Corzine Nov 2003

A Four-Level Crossing Dc/Dc Converter Based Drive System, X. Kou, Keith Corzine

Electrical and Computer Engineering Faculty Research & Creative Works

This paper introduces a novel crossing front-end dc/dc converter for a four-level drive system which provides a voltage boost as well as dc capacitor bank voltage regulation. The primary advantage of the proposed converter is that it simplifies the control of the four-level diode-clamped inverter since capacitor voltage balancing is not required by the inverter control. Furthermore, the inverter modulation index can be varied up to its physical limitation. An average-value model of the converter is derived and used for insight and analysis of the converter operation. Detailed simulations of the four-level drive system demonstrate the effectiveness of the proposed …

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Detection Of Weak Transitions In Signal Dynamics Using Recurrence Time Statistics, J. B. Gao, Yinhe Cao, Lingyun Gu, J. G. Harris, J. C. Principe Oct 2003

Detection Of Weak Transitions In Signal Dynamics Using Recurrence Time Statistics, J. B. Gao, Yinhe Cao, Lingyun Gu, J. G. Harris, J. C. Principe

Electrical and Computer Engineering Faculty Research & Creative Works

Signal detection in noisy and nonstationary environments is very challenging. In this Letter, we study why the two types of recurrence times [Phys. Rev. Lett. 83 (1999) 3178] may be very useful for detecting weak transitions in signal dynamics. We particularly emphasize that the recurrence times of the second type may be more powerful in detecting transitions with very low energy. These features are illustrated by studying a number of speech signals with fricatives and plosives. We have also shown that the recurrence times of the first type, nevertheless, has the distinguished feature of being more robust to the noise …

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Statistical Approach To The Emi Modeling Of Large Asics By A Single Noise-Current Source, Giulio Antonini, James L. Drewniak, Marco Leone, Antonio Orlandi, Vittorio Ricchiuti Oct 2003

Statistical Approach To The Emi Modeling Of Large Asics By A Single Noise-Current Source, Giulio Antonini, James L. Drewniak, Marco Leone, Antonio Orlandi, Vittorio Ricchiuti

Electrical and Computer Engineering Faculty Research & Creative Works

Large and complex ASICs are source of propagating noise inside the powerbus planes. A lumped noise source model is proposed and validated by means of a statistics based method.

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Suitability Of Pulse Train™, A Novel Digitally Implemented Real-Time Control Technique, For Bifred Converter, Mehdi Ferdowsi, Ali Emadi, Mark Telefus, Anatoly Shteynberg Oct 2003

Suitability Of Pulse Train™, A Novel Digitally Implemented Real-Time Control Technique, For Bifred Converter, Mehdi Ferdowsi, Ali Emadi, Mark Telefus, Anatoly Shteynberg

Electrical and Computer Engineering Faculty Research & Creative Works

Pulse TrainTM, a new control scheme, is presented and applied to a 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 is to regulate the output voltage using a series of high and low energy pulses generated by the current of the inductor. In this paper, 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 estimation are …

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Configuration For Micro Ph Sensor, Young-Jin Kim, Young-Chul Lee, Byung-Ki Sohn, Chang-Soo Kim, Jung-Hee Lee Oct 2003

Configuration For Micro Ph Sensor, Young-Jin Kim, Young-Chul Lee, Byung-Ki Sohn, Chang-Soo Kim, Jung-Hee Lee

Electrical and Computer Engineering Faculty Research & Creative Works

A fully integrated pH sensor with a built-in reference electrode is proposed. An iridium oxide microelectrode and a pH-insensitive field-effect transistor are used as a pH sensor and a reference electrode, respectively. The sensitivity of the proposed device matches well with the estimated value to within 0.3 mV/pH deviation.

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Electromagnetic Compatibility Issues In Mobile Computing, Antonio Orlandi, James L. Drewniak Oct 2003

Electromagnetic Compatibility Issues In Mobile Computing, Antonio Orlandi, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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Modeling And Analysis Of Fault Tolerant Multistage Interconnection Networks, Minsu Choi, Nohpill Park, Fabrizio Lombardi Oct 2003

Modeling And Analysis Of Fault Tolerant Multistage Interconnection Networks, Minsu Choi, Nohpill Park, Fabrizio Lombardi

Electrical and Computer Engineering Faculty Research & Creative Works

Performance and reliability are two of the most crucial issues in today's high-performance instrumentation and measurement systems. High speed and compact density multistage interconnection networks (MINs) are widely-used subsystems in different applications. New performance models are proposed to evaluate a novel fault tolerant MIN arrangement, thereby assuring performance and reliability with high confidence level. A concurrent fault detection and recovery scheme for MINs is considered by rerouting over redundant interconnection links under stringent real-time constraints for digital instrumentation as sensor networks. A switch architecture for concurrent testing and diagnosis is proposed. New performance models are developed and used to evaluate …

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Dcim-Accelerated Smfma For Capacitance Extraction, L. (Lijun) J. Jiang, W. C. Chew, Y. C. Pan Sep 2003

Dcim-Accelerated Smfma For Capacitance Extraction, L. (Lijun) J. Jiang, W. C. Chew, Y. C. Pan

Electrical and Computer Engineering Faculty Research & Creative Works

A new method to evaluate the SMFMA translators and near-field interactions for the capacitance extraction of the complicated structures in the multilayer medium is presented. As such, the spherical harmonic functions are extended into the complex plane to derive the closed forms of all multipole translators. This new technique can make the SMFMA setup stage one to two-orders faster compared to the old method. Moreover, it provides excellent accuracy with little computation costs.

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One-Layer Neural-Network Controller With Preprocessed Inputs For Autonomous Underwater Vehicles, Sarangapani Jagannathan, Gustavo Galan Sep 2003

One-Layer Neural-Network Controller With Preprocessed Inputs For Autonomous Underwater Vehicles, Sarangapani Jagannathan, Gustavo Galan

Electrical and Computer Engineering Faculty Research & Creative Works

Navigating, guiding, and controlling autonomous underwater vehicles (AUVs) are challenging and difficult tasks compared to the autonomous surface-level operations. Controlling the motion of such vehicles require the estimation of unknown hydrodynamic forces and moments and disturbances acting on these vehicles in the underwater environment. in this paper, a one-layer neural-network (NN) controller with preprocessed input signals is designed to control the vehicle track along a desired trajectory, which is specified in terms of desired position and attitude. in the absence of unknown disturbances and modeling errors, it is shown that the tracking error system is asymptotically stable. in the presence …

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Modified Fast Inhomogeneous Plane Wave Algorithm From Low Frequency To Microwave Frequency, L. (Lijun) J. Jiang, W. C. Chew Sep 2003

Modified Fast Inhomogeneous Plane Wave Algorithm From Low Frequency To Microwave Frequency, L. (Lijun) J. Jiang, W. C. Chew

Electrical and Computer Engineering Faculty Research & Creative Works

A new method, MFIPWA, is proposed to extend the traditional MLFMA and FIPWA into the low frequency range. It uses the evanescent-wave extrapolation and translation techniques to overcome the low-frequency breakdown problem. The accuracy can be well controlled over a broad frequency range.

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Spice Model Libraries For Via Transitions, Shaofeng Luan, Giuseppe Selli, Jun Fan, Mauro Lai, James L. Knighten, Norman W. Smith, Ray Alexander, Giulio Antonini, Antonio Ciccomancini, Antonio Orlandi, James L. Drewniak Aug 2003

Spice Model Libraries For Via Transitions, Shaofeng Luan, Giuseppe Selli, Jun Fan, Mauro Lai, James L. Knighten, Norman W. Smith, Ray Alexander, Giulio Antonini, Antonio Ciccomancini, Antonio Orlandi, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

A procedure of building SPICE models for signal via transitions between printed circuit board layers is presented in this paper. The method of extracting parameters of SPICE models from full-wave simulation tool is demonstrated. Then the validity of SPICE models is studied by comparing the solution from SPICE model with that from the full-wave simulation.

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Esd Excitation Model For Susceptibility Study, Federico Centola, David Pommerenke, Kai Wang, Thomas Van Doren, Spartaco Caniggia Aug 2003

Esd Excitation Model For Susceptibility Study, Federico Centola, David Pommerenke, Kai Wang, Thomas Van Doren, Spartaco Caniggia

Electrical and Computer Engineering Faculty Research & Creative Works

The paper provides a simplified model of a known ESD generator that allows modeling the ESD impulses (current and fields) in CST-Microwave Studio. The model is suitable for simulating the excitation of structures by ESD, but it is not intended to predict the fields and current of an ESD generator for its development purpose. The aim is to simultaneously model the ESD generator and a susceptible structure with as few details as possible but to obtain as good a match on current and fields as possible.

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Fdtd Modeling Of Isotropic Dispersive Magnetic Materials, Jing Wu, Marina Koledintseva, James L. Drewniak, David Pommerenke Aug 2003

Fdtd Modeling Of Isotropic Dispersive Magnetic Materials, Jing Wu, Marina Koledintseva, James L. Drewniak, David Pommerenke

Electrical and Computer Engineering Faculty Research & Creative Works

Numerical analysis using the finite-difference time-domain (FDTD) algorithm with a piecewise linear recursive convolution (PLRC) procedure for linear isotropic dispersive magnetic materials is presented. The frequency dependence of susceptibility used for this algorithm is represented in Debye, narrowband Lorentzian, and wideband Lorentzian forms, depending on the ratio of the resonance frequency and the resonance line width. Some numerical examples along with measurements are provided.

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Memory Dimm Dc Power Distribution Analysis And Design, Jingkun Mao, Chen Wang, Giuseppe Selli, Bruce Archambeault, James L. Drewniak Aug 2003

Memory Dimm Dc Power Distribution Analysis And Design, Jingkun Mao, Chen Wang, Giuseppe Selli, Bruce Archambeault, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

DC power bus design is critical in meeting signal integrity (SI) and electromagnetic compatibility (EMC) requirements. A suitable modeling tool is beneficial to evaluate power bus design and develop design guidelines. This paper discusses difficulties met in evaluating the power distribution design on a dual inline memory module (DIMM) board, such as a power bus with arbitrary shape, parasitic inductance associated with vias, and so on. Moreover, some solutions are given in this paper. A simple cavity model with a segmentation method was employed to model a power bus with irregular shapes. The partial element equivalent circuit (PEEC) technique was …

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Real-Time Dual Heuristic Programming-Based Neurocontroller For A Turbogenerator In A Multimachine Power System, Ganesh K. Venayagamoorthy, Ronald G. Harley, Donald C. Wunsch Aug 2003

Real-Time Dual Heuristic Programming-Based Neurocontroller For A Turbogenerator In A Multimachine Power System, Ganesh K. Venayagamoorthy, Ronald G. Harley, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

Based on Dual Heuristic Programming (DHP), a real-time implementation of a neurocontroller for excitation and turbine control of a turbogenerator in a multimachine power system is presented. The feedback variables are completely based on local measurements. Simulation and real-time hardware implementation on a three-machine system demonstrate that the DHP neurocontroller is much more effective than conventional PID controllers, the automatic voltage regulator, power system stabilizer and the governor, for improving dynamic performance and stability under small and large disturbances.

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Anticipating Emi Using Transfer Functions And Signal Integrity Information, Chen Wang, James L. Drewniak, Jim Nadolny Aug 2003

Anticipating Emi Using Transfer Functions And Signal Integrity Information, Chen Wang, James L. Drewniak, Jim Nadolny

Electrical and Computer Engineering Faculty Research & Creative Works

Discontinuities in a circuit can lead to signal integrity as well as EMI problems. A method, which efficiently combines full-wave tools and circuit simulators, is proposed herein to analyze the coupling at discontinuities. The proposed method may be applied to practical engineering designs.

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Anticipating Vehicle-Level Emi Using A Multi-Step Approach, Geping Liu, David Pommerenke, James L. Drewniak, Richard W. Kautz, Chingchi Chen Aug 2003

Anticipating Vehicle-Level Emi Using A Multi-Step Approach, Geping Liu, David Pommerenke, James L. Drewniak, Richard W. Kautz, Chingchi Chen

Electrical and Computer Engineering Faculty Research & Creative Works

A multi-step procedure for anticipating vehicle-level EMI is proposed in this paper. This approach uses multi-conductor transmission line (MTL) modeling to calculate current distributions along the cable bundle. A common-mode circuit is extracted from the MTL modeling, and is employed in full-vehicle full-wave modeling to determine radiation and interference. In this paper, mode-dispersion and mode-conversion phenomena are investigated, and the ambiguous definitions of the common-mode voltage and common-mode impedance are discussed.

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Impact Of Esd Generator Parameters On Failure Level In Fast Cmos System, Kai Wang, David Pommerenke, Kai Xiao, Ponniah Ilavarasan, Mike Schaffer, Ramachandran Chundru, Jiu Sheng Huang Aug 2003

Impact Of Esd Generator Parameters On Failure Level In Fast Cmos System, Kai Wang, David Pommerenke, Kai Xiao, Ponniah Ilavarasan, Mike Schaffer, Ramachandran Chundru, Jiu Sheng Huang

Electrical and Computer Engineering Faculty Research & Creative Works

Electrostatic discharge (ESD) generators are used for testing the robustness of electronics towards ESD. Most generators are built in accordance with the IEC 61000-4-2 specifications. It is shown that the voltage induced in a small loop correlates with the failure level observed in an ESD failure test on the systems comprising fast CMOS devices, while rise time and current derivative of the discharge current did not correlate well. The electric parameters are compared for typical and modified ESD generators and the effect on the failure level of fast CMOS electronics is investigated. The consequences of aligning an ESD standard with …

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Modeling Issues For Full-Wave Numerical Emi Simulation, Michael A. Cracraft, Xiaoning Ye, Chen Wang, Sandeep K. R. Chandra, James L. Drewniak Aug 2003

Modeling Issues For Full-Wave Numerical Emi Simulation, Michael A. Cracraft, Xiaoning Ye, Chen Wang, Sandeep K. R. Chandra, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

In electromagnetic modeling, agreement between modeling and measurements is a common goal. There are questions that define every model. What is to be modeled? How is it going to be modeled? At what scale is it to be modeled? Through sample results and discussion, this paper addresses some general and some specific elements of model veracity. Through determination, numerical models can certainly be pushed to match any measured results. However, in the end the question that this paper addresses is not necessarily "How good can this model be?" as it is "Is this model good enough?".

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Online Identification Of Turbogenerator's Dynamics Using A Neuro-Identifier, Wenxin Liu, Ganesh K. Venayagamoorthy, Donald C. Wunsch Aug 2003

Online Identification Of Turbogenerator's Dynamics Using A Neuro-Identifier, Wenxin Liu, Ganesh K. Venayagamoorthy, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

The increasing complexity of modern power systems highlights the need for effective system identification techniques for the successful control of power system. This paper proposes a robust continually online trained neuroidentifier to predict the outputs of turbogenerator - terminal voltage and speed deviation. The inputs to the neuro-identifier are the changes of the plant's outputs and plant's inputs. It overcomes the drawback of calculating deviation signals from reference signals for different operating points in previous work. Simulation results show that the neuro-identifier can provide accurate identification under different operating conditions. Furthermore, the neuro-identifier can learn the dynamics of the system …

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Fdtd Method Capable Of Attaching Rectangular Domains, Kai Xiao, David Pommerenke, James L. Drewniak Aug 2003

Fdtd Method Capable Of Attaching Rectangular Domains, Kai Xiao, David Pommerenke, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

A finite-difference time-domain (FDTD) method capable of attaching rectangular computational domains is proposed herein. The aim of this approach is to reduce the size of computational domain according to the geometry of the modeled structure so as to reduce the simulation time with keeping precision of the result in an acceptable range. A multigrid algorithm is applied on the attaching interface between two rectangular domains so that different resolution can be achieved in different domains.

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