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- Finite Difference Time-Domain Analysis (4)
- Power System Analysis Computing (4)
- Common-Mode Radiation (3)
- Electromagnetic Interference (3)
- Mathematical Models (3)
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- Power System Control (3)
- Printed Circuit Boards (3)
- Attached Cables (2)
- Computer Simulation (2)
- Covered Cracks (2)
- Crack Detection (2)
- Distribution Networks (2)
- Electric Sensing Devices (2)
- Electromagnetic Shielding (2)
- Electromagnetic Wave Interference (2)
- Filled Cracks (2)
- Integral Equations (2)
- Learning (Artificial Intelligence) (2)
- Load Dispatching (2)
- Medical Diagnostic Imaging (2)
- Medical Image Processing (2)
- Metals (2)
- Microwave Measurement (2)
- Neural Nets (2)
- Nondestructive Testing (2)
- Numerical Methods (2)
- Numerical Stability (2)
- Power System Stability (2)
- Power Systems (2)
- Printed Circuit Design (2)
Articles 1 - 25 of 25
Full-Text Articles in Engineering
A Multimedia Manual On The World Wide Web For Telecommunications Equipment, Andrew L. Sears, Steve E. Watkins
A Multimedia Manual On The World Wide Web For Telecommunications Equipment, Andrew L. Sears, Steve E. Watkins
Electrical and Computer Engineering Faculty Research & Creative Works
An interactive multimedia educational manual on the Internet through the World Wide Web for commercial optical fiber telecommunications equipment is described. The Telecommunications Laboratory Manual is a vehicle for enhancing engineering education with realistic laboratory or virtual laboratory experience. The manual provides a brief system tutorial, operating instructions, on-line help, and multimedia experimental demonstrations. It incorporates block diagrams, photographic images, and hypertext links that are mouse clickable, allowing users to access documents or links describing components or processes in any order. An experimental section guides students through laboratory experiences, demonstrates selected equipment characteristics, and provides for direct instructor contact through …
Investigation Of Fundamental Emi Source Mechanisms Driving Common-Mode Radiation From Printed Circuit Boards With Attached Cables, David M. Hockanson, James L. Drewniak, Todd H. Hubing, Thomas Van Doren, Fei Sha, Michael J. Wilhelm
Investigation Of Fundamental Emi Source Mechanisms Driving Common-Mode Radiation From Printed Circuit Boards With Attached Cables, David M. Hockanson, James L. Drewniak, Todd H. Hubing, Thomas Van Doren, Fei Sha, Michael J. Wilhelm
Electrical and Computer Engineering Faculty Research & Creative Works
Fundamental EMI source mechanisms leading to common-mode radiation from printed circuit boards with attached cables are presented in this paper. Two primary EMI source mechanisms have been identified: one associated with a differential-mode voltage and another associated with a differential-mode current, both of which result in a common-mode current on an attached cable. These mechanisms can be used to relate printed circuit layout geometries to EMI sources. The two mechanisms are demonstrated through numerical and experimental results, and an example from a production printed-circuit design is presented.
Generation Of Synthetic-Focus Images From Pulse-Echo Ultrasound Using Difference Equations, Daryl G. Beetner, R. Martin Arthur
Generation Of Synthetic-Focus Images From Pulse-Echo Ultrasound Using Difference Equations, Daryl G. Beetner, R. Martin Arthur
Electrical and Computer Engineering Faculty Research & Creative Works
To produce a complete-dataset, pulse-echo image requires a knowledge of the time of flight (TOF) from each source to each sensor in the transducer array for each site to be imaged. Increasing the speed of TOF calculation is important in adaptive-focus schemes. The authors determined TOF more rapidly than via direct calculation by representing TOF surfaces by two-dimensional (2-D), positive-integer-degree polynomials implemented in their forward-difference form. Errors which accumulate due to the use of a difference equation depend on the degree of the polynomial and on the size of the image. The number of bits needed to address echo samples …
Detecting Stress And Fatigue Cracks, Christian J. Huber, R. Zoughi
Detecting Stress And Fatigue Cracks, Christian J. Huber, R. Zoughi
Electrical and Computer Engineering Faculty Research & Creative Works
Discoveries in using open ended rectangular waveguides for microwave surface crack detection and sizing have generated interest. The foundation, potential, advantages and disadvantages of this methodology, developed at the Applied Microwave Nondestructive Testing Laboratory in the Electrical Engineering Department at Colorado State University, are discussed. Microwave techniques in general and this particular approach offer certain unique advantages that can advance the state of the art of fatigue/surface crack detection. The basic features and capabilities of this technique have been theoretically and experimentally investigated these past few years. However, more developmental work is needed to bring this technique from the laboratory …
Experimental And Numerical Investigations Of Fundamental Radiation Mechanisms In Pcb Designs With Attached Cables, David M. Hockanson, Cheung-Wei Lam, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
Experimental And Numerical Investigations Of Fundamental Radiation Mechanisms In Pcb Designs With Attached Cables, David M. Hockanson, Cheung-Wei Lam, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
Electrical and Computer Engineering Faculty Research & Creative Works
Stacked-card and modules-on-backplane printed circuit board geometries are advantageous for conserving real-estate in many designs. Unfortunately, at high frequencies, current-driven noise sources may develop at the connector. The connector may effectively drive the daughter-card against the motherboard and attached cables, resulting in common-mode radiation. The connector geometry can be modified to reduce the level of the effective noise-source when high frequencies are routed between the mother-board and daughter-card. Current speeds and PCB board sizes result in geometries that are of significant dimensions in terms of wavelength at the upper frequency end of the signal spectrum. Geometries are then of sufficient …
Fdtd Modeling Of Common-Mode Radiation From Cables, David M. Hockanson, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
Fdtd Modeling Of Common-Mode Radiation From Cables, David M. Hockanson, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
Electrical and Computer Engineering Faculty Research & Creative Works
Radiation from cables attached to printed circuit boards and shielding enclosures is among the primary concerns in meeting FCC Class A and B limits. The finite-difference time-domain (FDTD) method can be employed to model radiation from printed circuit boards and shielding enclosures with complex geometries, but difficulties in modeling wires and cables of arbitrary radii are encountered. Modeling the wire by setting the axial component of the electric field to zero in the FDTD method results in an effective wire radius that is determined by the mesh discretization. Neglecting the wire radius in applications, such as electromagnetic interference (EMI) or …
A Comparison Of An Fdtd Thin-Slot Algorithm And Method Of Moments For Modeling Slots Near Corners, Kuang-Ping Ma, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
A Comparison Of An Fdtd Thin-Slot Algorithm And Method Of Moments For Modeling Slots Near Corners, Kuang-Ping Ma, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
Electrical and Computer Engineering Faculty Research & Creative Works
Subcellular FDTD algorithms for modeling thin slots in conductors have previously been developed. One algorithm that is based on a quasi-static approximation has been shown to agree well with experimental results for thin slots in planes. This FDTD thin-slot algorithm is compared herein with moment method results for thin slots near corners.
A Multi-Institutional Cooperative Approach To Power Engineering Education, Anil Pahwa, Kraig J. Olejniczak, S. D. Sughoff, Shelli K. Starrett, Mariesa Crow
A Multi-Institutional Cooperative Approach To Power Engineering Education, Anil Pahwa, Kraig J. Olejniczak, S. D. Sughoff, Shelli K. Starrett, Mariesa Crow
Electrical and Computer Engineering Faculty Research & Creative Works
This paper describes the multi-institutional cooperative effort between the University of Missouri--Rolla, Kansas State University, and the University of Arkansas to develop two new courses in flexible power system control.
Simulation And Measurement For Decoupling On Multilayer Pcb Dc Power Buses, Hao Shi, F. Yuan, Fei Sha, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
Simulation And Measurement For Decoupling On Multilayer Pcb Dc Power Buses, Hao Shi, F. Yuan, Fei Sha, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
Electrical and Computer Engineering Faculty Research & Creative Works
DC power bus decoupling of a multi-layer PCB is modeled by a combination of a lumped circuit model at low frequencies ( < 200 MHz), and a mixed-potential integral equation approach at high frequencies. In order to determine the lumped parameters of via interconnects, an effective procedure using a network analyzer has been developed to characterize the trace/via inductances/resistances. For an 8 inch × 10 inch ten-layer test board used in this study, the simulations show good agreement with the measurement. This method can lead to new design strategies of decoupling for multilayer PCB power buses.
An Expert System Approach To Emc Modeling, Todd H. Hubing, James L. Drewniak, Thomas Van Doren, Navin Kashyap
An Expert System Approach To Emc Modeling, Todd H. Hubing, James L. Drewniak, Thomas Van Doren, Navin Kashyap
Electrical and Computer Engineering Faculty Research & Creative Works
Existing computer software for EMC analysis can be divided into three categories. Analytical modeling codes employ closed form expressions to solve problems of general interest to EMC engineers or circuit designers. Numerical modeling codes use numerical techniques to solve Maxwell's equations subject to specific boundary conditions. EMC rule checkers search a design for features that violate basic EMC design guidelines. This paper outlines the relative advantages and limitations of each of these three approaches and describes an expert system EMC modeling approach. The new approach combines analytical models, numerical models, and EMC rule-checking in order to evaluate designs in much …
Measurement Parameter Optimization For Surface Crack Detection In Metals Using An Open-Ended Waveguide Probe, R. Zoughi, Stoyan I. Ganchev, Christian J. Huber
Measurement Parameter Optimization For Surface Crack Detection In Metals Using An Open-Ended Waveguide Probe, R. Zoughi, Stoyan I. Ganchev, Christian J. Huber
Electrical and Computer Engineering Faculty Research & Creative Works
Fatigue and stress induced surface crack detection in metals is an important practical issue. A newly developed microwave inspection approach, using an open-ended rectangular waveguide, has proved to be an effective tool for detecting such cracks. This novel microwave approach overcomes some of the limitations associated with the standard detection methods for surface crack detection. In addition, this approach is applicable to exposed, filled (with a dielectric such as dirt, rust, etc.) and cracks under dielectric coatings such as paint. This paper presents the basic foundation of this surface crack detection methodology along with the ways by which measurement parameters …
A Fuzzy Logic Based Approach To Direct Load Control, K. Bhattacharyya, Mariesa Crow
A Fuzzy Logic Based Approach To Direct Load Control, K. Bhattacharyya, Mariesa Crow
Electrical and Computer Engineering Faculty Research & Creative Works
Demand side management programs are strategies designed to alter the shape of the load curve. In order to successfully implement such a strategy, customer acceptance of the program is vital. It is thus desirable to design a model for direct load control which may accommodate customer preferences. This paper presents a methodology for optimizing both customer satisfaction and utility unit commitment savings, based on a fuzzy load model for the direct load control of appliances
Dispersion Comparison For Dsi- And Tensor-Based Nonorthogonal Fdtd, Hao Shi, James L. Drewniak
Dispersion Comparison For Dsi- And Tensor-Based Nonorthogonal Fdtd, Hao Shi, James L. Drewniak
Electrical and Computer Engineering Faculty Research & Creative Works
An explicit formulation of the finite-difference time-domain-discrete surface integral (FDTD-DSI) technique has allowed a rigorous study of numerical dispersion for the method. The study shows that the DSI- and tensor-based FDTD methods do not have the same numerical dispersion relation. It also clarifies the recently reported discrepancies in the dispersion relation between the two approaches. This study also shows that the tensor-based FDTD algorithm exhibits better dispersion properties for a two-dimensional uniformly skewed mesh.
The Multirate Simulation Of Facts Devices In Power System Dynamics, J. G. Chen, Mariesa Crow
The Multirate Simulation Of Facts Devices In Power System Dynamics, J. G. Chen, Mariesa Crow
Electrical and Computer Engineering Faculty Research & Creative Works
In this paper, the multirate method is applied to the problem of simulating the dynamics of a power system which contains fast components such as induction machine loads and FACTS devices. Results concerning the numerical stability and accuracy of the multirate method are presented. Implementation concerns are also addressed by studying an example power system which contains a wide range of time response behavior
Two Methods Of Neural Network Controlled Dynamic Channel Allocation For Mobile Radio Systems, Kelvin T. Erickson, Edward J. Wilmes
Two Methods Of Neural Network Controlled Dynamic Channel Allocation For Mobile Radio Systems, Kelvin T. Erickson, Edward J. Wilmes
Electrical and Computer Engineering Faculty Research & Creative Works
Two methods of dynamic channel allocation using neural networks are investigated. Both methods continuously optimize the mobile network based on changes in calling traffic. The first method uses backpropagation model predictions to aid the channel allocator. Each cell contains a backpropagation model which provides the channel allocator a call traffic prediction allowing the channel allocator to effectively optimize the network. The second method uses the same backpropagation models along with actor-critic models to perform the channel allocation. The actor-critics learn to model traffic activity between adjacent cells in real-time, and thereby learn to allocate channels dynamically between cells. The learning …
Interaction Between Millimeter Oscillations And Monocrystal Hexagonal Ferrites With Modulated Resonance Frequency, Alexander A. Kitaytsev, Marina Koledintseva
Interaction Between Millimeter Oscillations And Monocrystal Hexagonal Ferrites With Modulated Resonance Frequency, Alexander A. Kitaytsev, Marina Koledintseva
Electrical and Computer Engineering Faculty Research & Creative Works
Investigation of non-linear stable effects taking place at ferromagnetic resonance (FMR) in monocrystal arbitrarily oriented hexagonal ferrite resonators (HFR) with controlled (modulated) resonance frequency is an urgent problem. The presented analysis is based on two approaches: the “quasistatic” approach using the static tensor of the HFR magnetic susceptibility and the “dynamic” one based on the solution of the magnetization vector motion equation (MVME) with varying time coefficients due to modulated magnetization field or HFR angle of orientation. The first approach is valid at low modulation frequencies (in comparison with the relaxation frequency of the HFR) and the second one can …
Security-Constrained Optimal Rescheduling Of Real Power Using Hopfield Neural Network, S. Ghosh, Badrul H. Chowdhury
Security-Constrained Optimal Rescheduling Of Real Power Using Hopfield Neural Network, S. Ghosh, Badrul H. Chowdhury
Electrical and Computer Engineering Faculty Research & Creative Works
A new method for security-constrained corrective rescheduling of real power using the Hopfield neural network is presented. The proposed method is based on solution of a set of differential equations obtained from transformation of an energy function. Results from this work are compared with the results from a method based on dual linear programming formulation of the optimal corrective rescheduling. The minimum deviations in real power generations and loads at buses are combined to form the objective function for optimization. Inclusion of inequality constraints on active line flow limits and equality constraint on real power generation load balance assures a …
Programmable Logic Controllers, Kelvin T. Erickson
Programmable Logic Controllers, Kelvin T. Erickson
Electrical and Computer Engineering Faculty Research & Creative Works
Programmable logic controllers (PLCs) are at the forefront of manufacturing automation. Many factories use programmable logic controllers to cut production costs and/or increase quality. PLCs and their unique language, ladder logic, are the workhorses of factory automation. Higher-level languages, such as sequential function charts and function blocks, ease the programming task for large systems. However, ladder logic remains the dominant language at present
Evaluating The Value Of Distributed Photovoltaic Generations In Radial Distribution Systems, Badrul H. Chowdhury, A. W. Sawab
Evaluating The Value Of Distributed Photovoltaic Generations In Radial Distribution Systems, Badrul H. Chowdhury, A. W. Sawab
Electrical and Computer Engineering Faculty Research & Creative Works
The impact of photovoltaic (PV) generations, when added to an existing rural utility's distribution system, is studied. The addition of PV is examined in the light of voltage support, loss reduction, and reduction in peak demand. Comparisons are made with the conventional and widely used methods for voltage control and loss minimization, such as the addition of series and shunt capacitors and voltage regulators. The economics of distributed PV systems in the context of conventional grid power purchases are also studied. Results of this study are meant to be used as general guidelines for evaluating the impact of significant PV …
A Hybrid Observer For High Performance Brushless Dc Motor Drives, Keith Corzine, S. D. Sudhoff
A Hybrid Observer For High Performance Brushless Dc Motor Drives, Keith Corzine, S. D. Sudhoff
Electrical and Computer Engineering Faculty Research & Creative Works
Brushless DC motor drive systems are used in a wide variety of applications. These drives may be classified as being one of two types: sinusoidal drives in which there are no low-frequency harmonics in the current waveforms and no low-frequency torque ripple; and nonsinusoidal drives in which there is considerable low-frequency harmonic content, both in the current and torque waveforms. Although sinusoidal drives feature superior performance, they are generally more expensive since rotor position must be sensed on a continuous basis, thus requiring an optical encoder or a resolver, whereas relatively inexpensive Hall-effect sensors may be used for nonsinusoidal drives. …
Fault Classification Using Kohonen Feature Mapping, Badrul H. Chowdhury, Kunyu Wang
Fault Classification Using Kohonen Feature Mapping, Badrul H. Chowdhury, Kunyu Wang
Electrical and Computer Engineering Faculty Research & Creative Works
Applications of neural networks to power system fault diagnosis have provided positive results and shown advantages in process speed over conventional approaches. This paper describes the application of a Kohonen neural network to fault detection and classification using the fundamental components of currents and voltages. The Electromagnetic Transients Program is used to obtain fault patterns for the training and testing of neural networks. Accurate classifications are obtained for all types of possible short circuit faults on test systems representing high voltage transmission lines. Short training time makes the Kohonen network suitable for on-line power system fault diagnosis. The method introduced …
Dynamically Regularized Fast Rls With Application To Echo Cancellation, Steven L. Grant
Dynamically Regularized Fast Rls With Application To Echo Cancellation, Steven L. Grant
Electrical and Computer Engineering Faculty Research & Creative Works
This paper introduces a dynamically regularized fast recursive least squares (DR-FRLS) adaptive filtering algorithm. Numerically stabilized FRLS algorithms exhibit reliable and fast convergence with low complexity even when the excitation signal is highly self-correlated. FRLS still suffers from instability, however, when the condition number of the implicit excitation sample covariance matrix is very high. DR-FRLS, overcomes this problem with a regularization process which only increases the computational complexity by 50%. The benefits of regularization include: (1) the ability to use small forgetting factors resulting in improved tracking ability and (2) better convergence over the standard regularization technique of noise injection. …
Input Dimension Reduction In Neural Network Training-Case Study In Transient Stability Assessment Of Large Systems, S. Muknahallipatna, Badrul H. Chowdhury
Input Dimension Reduction In Neural Network Training-Case Study In Transient Stability Assessment Of Large Systems, S. Muknahallipatna, Badrul H. Chowdhury
Electrical and Computer Engineering Faculty Research & Creative Works
The problem in modeling large systems by artificial neural networks (ANN) is that the size of the input vector can become excessively large. This condition can potentially increase the likelihood of convergence problems for the training algorithm adopted. Besides, the memory requirement and the processing time also increase. This paper addresses the issue of ANN input dimension reduction. Two different methods are discussed and compared for efficiency and accuracy when applied to transient stability assessment.
Transient And Dynamic Average-Value Modeling Of Synchronous Machine Fed Load-Commutated Converters, Keith Corzine, S. D. Sudhoff, H. J. Hegner, D. E. Delisle
Transient And Dynamic Average-Value Modeling Of Synchronous Machine Fed Load-Commutated Converters, Keith Corzine, S. D. Sudhoff, H. J. Hegner, D. E. Delisle
Electrical and Computer Engineering Faculty Research & Creative Works
A new average-value model of a synchronous machine fed load-commutated converter is set forth in which the stator dynamics are combined with the DC link dynamics. This model is shown to he extremely accurate in predicting system transients and in predicting frequency-domain characteristics such as the impedance looking into the synchronous machine fed load-commutated converter. The model is verified against a detailed computer simulation and against a hardware test system, thus providing a three-way comparison. The proposed model is shown to be much more accurate than models in which the stator dynamics are neglected
Unsupervised Color Image Segmentation: With Application To Skin Tumor Borders, Randy Hays Moss, G. A. Hance, Scott E. Umbaugh, William V. Stoecker
Unsupervised Color Image Segmentation: With Application To Skin Tumor Borders, Randy Hays Moss, G. A. Hance, Scott E. Umbaugh, William V. Stoecker
Electrical and Computer Engineering Faculty Research & Creative Works
The images used in this research were digitized from 35mm color photographic slides obtained from a private dermatology practice and from New York University. The authors compared 6 color segmentation methods and their effectiveness as part of an overall border-finding algorithm. The PCT/median cut and adaptive thresholding algorithms provided the lowest average error and show the most promise for further individual algorithm development. Combining the different methods resulted in further improvement in the number of correctly identified tumor borders, and by incorporating additional heuristics in merging the segmented object information, one could potentially further increase the success rate. The algorithm …