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Articles 3151 - 3180 of 3518
Full-Text Articles in Engineering
Investigation Of Split Groundplanes At The Connector For Emi Control, David M. Hockanson, James L. Drewniak, Joe Nuebel, James C. Parker Jr.
Investigation Of Split Groundplanes At The Connector For Emi Control, David M. Hockanson, James L. Drewniak, Joe Nuebel, James C. Parker Jr.
Electrical and Computer Engineering Faculty Research & Creative Works
EMI can often be reduced by selectively filtering various parts of a given system. One common method employed by designers is to split the groundplane near the chassis and route I/O lines over the split. The rationale is based on providing a large series impedance to common-mode currents on the I/O lines. In this manner, PCB designers hope to lower the level of noise currents contributing to radiation. This work studies the efficacy of the groundplane split as a deterrent for EMI associated with I/O lines being driven against other extended reference structures. A test-board was developed to analyze the …
Emi From Apertures At Enclosure Cavity Mode Resonances, Min Li, Yun Ji, S. Radu, Joe Nuebel, Wei Cui, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
Emi From Apertures At Enclosure Cavity Mode Resonances, Min Li, Yun Ji, S. Radu, Joe Nuebel, Wei Cui, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
Electrical and Computer Engineering Faculty Research & Creative Works
EMI from slots and apertures resulting from coupling of interior sources through enclosure cavity modes in a Sun S-1000 workstation was investigated. The excitation of a specially designed rectangular enclosure with a slot was also studied experimentally and with finite-difference time-domain (FDTD) simulations. The radiated power results for both the S-1000 and simple rectangular enclosure indicate that radiation at cavity mode resonance frequencies through slots and apertures can be as significant as at aperture or slot resonances. A decrease of the radiation through the slots and apertures can be achieved by employing a lossy material in the enclosure.
Effects Of Gapped Groundplanes And Guard Traces On Radiated Emi, D. S. Britt, David M. Hockanson, Fei Sha, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
Effects Of Gapped Groundplanes And Guard Traces On Radiated Emi, D. S. Britt, David M. Hockanson, Fei Sha, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
Electrical and Computer Engineering Faculty Research & Creative Works
Designers sometimes employ gapped reference planes to isolate analog and digital signals, and separate "quiet" and "noisy" ground structures by providing a series impedance. Guard traces are also used to reduce unwanted coupling to adjacent traces, which can lead to signal integrity or EMI problems. This study investigates the impact of gaps and guard traces on radiated EMI. A simple microstrip circuit was constructed to experimentally analyze the effects of groundplane gaps and guard traces.
Lumped-Element Sections For Modeling Coupling Between High-Speed Digital And I/O Lines, Wei Cui, Hao Shi, Xiao Luo, Fei Sha, James L. Drewniak, Thomas Van Doren, T. Anderson
Lumped-Element Sections For Modeling Coupling Between High-Speed Digital And I/O Lines, Wei Cui, Hao Shi, Xiao Luo, Fei Sha, James L. Drewniak, Thomas Van Doren, T. Anderson
Electrical and Computer Engineering Faculty Research & Creative Works
Lumped-element sections are used for modeling coupling between high-speed digital and I/O lines on printed circuit boards (PCBs) in this paper. Radiated electromagnetic interference (EMI) is investigated when the I/O line going off the board is driven as an unintentional, but effective antenna. Simulated results are compared with measurements for coupled lines. A suitable number of lumped-element sections for modeling is chosen based on the line length and the highest frequency of interest.
Numerical And Experimental Corroboration Of An Fdtd Thin-Slot Model For Slots Near Corners Of Shielding Enclosures, Min Li, Kuang-Ping Ma, David M. Hockanson, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
Numerical And Experimental Corroboration Of An Fdtd Thin-Slot Model For Slots Near Corners Of Shielding Enclosures, Min Li, Kuang-Ping Ma, David M. Hockanson, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
Electrical and Computer Engineering Faculty Research & Creative Works
Simple design maxims to restrict slot dimensions in enclosure designs below a half-wave length are not always adequate for minimizing electromagnetic interference (EMI). Complex interactions between cavity modes, sources, and slots can result in appreciable radiation through nonresonant length slots. The finite-difference time domain (FDTD) method can be employed to pursue these issues with adequate modeling of thin slots. Subcellular FDTD algorithms for modeling thin slots in conductors have previously been developed. One algorithm based on a quasistatic approximation has been shown to agree well with experimental results for thin slots in planes. This FDTD thin-slot algorithm is compared herein …
An Expert System For Predicting Radiated Emi From Pcb's, Navin Kashyap, Todd H. Hubing, James L. Drewniak, Thomas Van Doren
An Expert System For Predicting Radiated Emi From Pcb's, Navin Kashyap, Todd H. Hubing, James L. Drewniak, Thomas Van Doren
Electrical and Computer Engineering Faculty Research & Creative Works
This paper describes an expert systems approach, based on symbolic reasoning techniques, to the problem of predicting radiated EMI levels from printed circuit boards. The expert system, currently under development at the University of Missouri-Rolla, USA, starts by extracting board geometry information from the board layout files. This information is fed into the classification algorithm, which determines the signal properties and nature of each net, using the knowledge stored in the knowledge base. The evaluation algorithm uses the available in formation to identify and evaluate critical circuit geometries, and then estimates the effect that these geometries have on system radiation …
Robust Control Of Smart Structures Using Neural Network Hardware, Rajendra Damle, Vittal Rao, Frank J. Kern
Robust Control Of Smart Structures Using Neural Network Hardware, Rajendra Damle, Vittal Rao, Frank J. Kern
Electrical and Computer Engineering Faculty Research & Creative Works
In this paper, the use of Intel's Electronically Trainable Analog Neural Network (ETANN) chipi80170NX for implementing single-chip robust controllers for smart structures is successfully demonstrated. Robust controllers like the linear quadratic regulator (LQR) and linear quadratic Gaussian with loop transfer recovery (LQG/LTR) are implemented in various configurations using the ETANN chip on the smart structure test article. The test article is a cantilevered plate with PZTs as actuators and shaded PVDF film as sensors. The spatially distributed sensors allow direct measurement of the states of the system enabling the implementation of the LQR controller. A two step connectionist approach is …
Mechanism Of Anomalous Photoinduced Transient Current Peak In Amorphous Silicon Thin-Film Transistor, M. H. Chu, Cheng-Hsiao Wu
Mechanism Of Anomalous Photoinduced Transient Current Peak In Amorphous Silicon Thin-Film Transistor, M. H. Chu, Cheng-Hsiao Wu
Electrical and Computer Engineering Faculty Research & Creative Works
The photoinduced transient current from an amorphous silicon thin-film transistor is computed and the mechanism described in terms of trap-state filling dynamics. The direction of the current flow and the location of the transient peak depends strongly on the distributions of donorlike and acceptorlike trap states in the neighborhood of the dark Fermi level. We show that the transient current can flow in the same direction as in the crystalline transistor, as well as in the opposite direction. There is also an interesting cross-over behavior in which the transient current flows out of the drain terminal as a pulse of …
Comparison Of Fdtd Algorithms For Subcellular Modeling Of Slots In Shielding Enclosures, Kuang-Ping Ma, Min Li, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
Comparison Of Fdtd Algorithms For Subcellular Modeling Of Slots In Shielding Enclosures, Kuang-Ping Ma, Min Li, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
Electrical and Computer Engineering Faculty Research & Creative Works
Subcellular modeling of thin slots in the finite-difference time-domain (FDTD) method is investigated. Two subcellular algorithms for modeling thin slots with the FDTD method are compared for application to shielding end osures in electromagnetic compatibility (EMC). The stability of the algorithms is investigated, and comparisons between the two methods for slots in planes, and slots in loaded cavities are made. Results for scattering from a finite-length slot in an infinite plane employing one of the algorithms are shown to agree well with published experimental results, and power delivered to an enclosure with a slot agree well with results measured for …
Analysis Of The "Crack Characteristic Signal" Using A Generalized Scattering Matrix Representation, Christian J. Huber, Habibollah Abiri, R. Zoughi, Stoyan I. Ganchev
Analysis Of The "Crack Characteristic Signal" Using A Generalized Scattering Matrix Representation, Christian J. Huber, Habibollah Abiri, R. Zoughi, Stoyan I. Ganchev
Electrical and Computer Engineering Faculty Research & Creative Works
Electromagnetic properties of a system formed by an open-ended rectangular waveguide and a surface crack/slot in a metallic specimen are described in this paper. Scanning a crack on a metal surface changes the reflection coefficient of the incident dominant mode. A model as a function of relative crack location within the waveguide aperture (i.e., crack moving with respect to the waveguide aperture) is desired to describe and optimize practical crack detection applications. Hence, the change in the reflection coefficient for a generalized system encompassing empty, filled, and finite cracks located at an arbitrary position inside the waveguide aperture, is evaluated. …
An Analog Integrated Circuit For Continuous-Time Gain And Offset Calibration Of Sensor Arrays, Yu Ming Chiang, John G. Harris
An Analog Integrated Circuit For Continuous-Time Gain And Offset Calibration Of Sensor Arrays, Yu Ming Chiang, John G. Harris
Electrical and Computer Engineering Faculty Research & Creative Works
Parameter variations cause unavoidable nonuniformities in Infra-Red Focal Plane Arrays and other integrated sensors. Since these nonuniformities change slowly with time, calibrating sensors one-time only is not suitable-much more frequent calibration is required. We have developed an algorithm that continually calibrates an array of sensors that contain gain and offset variations. This algorithm has been mapped to analog hardware and designed and fabricated with a 2um CMOS technology. Measured results from the chip show that the system achieves invariance to gain and offset variations of the input signal.
Neutron Transmutation Doping As An Experimental Probe For Cuzn In Znse, Edward D. Wheeler, Jack L. Boone, J. W. Farmer, H. R. Chandrasekhar
Neutron Transmutation Doping As An Experimental Probe For Cuzn In Znse, Edward D. Wheeler, Jack L. Boone, J. W. Farmer, H. R. Chandrasekhar
Electrical and Computer Engineering Faculty Research & Creative Works
Nuclear transmutation is employed in an investigation of copper doping in ZnSe. Copper atoms are introduced at zinc sites in ZnSe after crystal growth processes are complete. Since the copper dopants are introduced after growth, far from equilibrium, they are less able to form complexes with other dopants or lattice defects as they may do when present during crystal growth. Initial results are consistent with CuZn being involved in the copper red and copper green emissions in ZnSe but not in the if exitonic emission. © 1997 American Institute of Physics.
Miniaturized Isfet Glucose Sensor Including A New Structure Actuation System, Chang-Soo Kim, Hwa-Il Seo, Chae-Hyang Lee, Byung-Ki Sohn
Miniaturized Isfet Glucose Sensor Including A New Structure Actuation System, Chang-Soo Kim, Hwa-Il Seo, Chae-Hyang Lee, Byung-Ki Sohn
Electrical and Computer Engineering Faculty Research & Creative Works
A new principle of an amperometric actuation technique was incorporated in the ISFET glucose sensor. The ISFET is fabricated by the CMOS process and the platinum working electrode is deposited by the lift-off process. A sensor with a specially designed ladder type working electrode exhibits improved operation in response time, response magnitude and detection range. An expectation concerning the reduction of sensor size is also discussed.
Stability Of Discrete-Time Matrix Polynomials, Khanh Tu Ngo, Kelvin T. Erickson
Stability Of Discrete-Time Matrix Polynomials, Khanh Tu Ngo, Kelvin T. Erickson
Electrical and Computer Engineering Faculty Research & Creative Works
This paper derives conditions for the stability of discrete-time systems that can be modeled by a vector difference equation, where the variables are m x 1 vectors and the coefficients are m x m matrices. Stability of the system is related to the locations of the roots of the determinant of a real m x m matrix polynomial of nth order. In this case, sufficient conditions for the system to be stable are derived. The conditions are imposed on the infinity norm of two matrices constructed from the coefficient matrices and do not require the computation of the determinant polynomial. …
Adaptive Critic Design In Learning To Play Game Of Go, R. Zaman, Danil V. Prokhorov, Donald C. Wunsch
Adaptive Critic Design In Learning To Play Game Of Go, R. Zaman, Danil V. Prokhorov, Donald C. Wunsch
Electrical and Computer Engineering Faculty Research & Creative Works
This paper examines the performance of an HDP-type adaptive critic design (ACD) of the game Go. The game Go is an ideal problem domain for exploring machine learning; it has simple rules but requires complex strategies to play well. All current commercial Go programs are knowledge based implementations; they utilize input feature and pattern matching along with minimax type search techniques. But the extremely high branching factor puts a limit on their capabilities, and they are very weak compared to the relative strengths of other game programs like chess. In this paper, the Go-playing ACD consists of a critic network …
The New--But Is It Improved?--Power System, Mariesa Crow
The New--But Is It Improved?--Power System, Mariesa Crow
Electrical and Computer Engineering Faculty Research & Creative Works
In this paper, the author examines the effect that deregulation will have on the US power system. The paper details how the electric power industry in the USA is undergoing major changes, both politically and technically, as a result of the Federal Energy Regulatory Commission's Orders 888 and 889 issued in 1996. These orders essentially deregulate the transmission network, allowing producers and customers access to the network for electricity transactions.
A 50 Kilowatt Distributed Grid-Connected Photovoltaic Generation System For The University Of Wyoming, Badrul H. Chowdhury, S. Muknahallipatna, T. Dinwoodie, D. Shugar, J. J. Cupal, J. C. Hamann
A 50 Kilowatt Distributed Grid-Connected Photovoltaic Generation System For The University Of Wyoming, Badrul H. Chowdhury, S. Muknahallipatna, T. Dinwoodie, D. Shugar, J. J. Cupal, J. C. Hamann
Electrical and Computer Engineering Faculty Research & Creative Works
The University of Wyoming (UW) campus (USA) is serving as the site for a 50 kilowatt solar photovoltaic (PV) power system. Three sub-systems were sited and built on the UW campus in 1996. The first sub-system, a 10 kW roof-integrated system of PV roof tiles is located on the roof of the Engineering Building. The second sub-system-a 5 kW rack-mounted, ballasted PV system is on a walkway roof of the Engineering building. The third sub-system is a 35 kW shade structure system and is located adjacent to the parking lot of the University's football stadium. The three sub-systems differ in …
Effect Of Cl Incorporation On The Performance Of Amorphous Silicon Thin Film Transistor, Jong Hyuni Choi, Chang-Soo Kim, Sung Ki Kim, Jin Jang
Effect Of Cl Incorporation On The Performance Of Amorphous Silicon Thin Film Transistor, Jong Hyuni Choi, Chang-Soo Kim, Sung Ki Kim, Jin Jang
Electrical and Computer Engineering Faculty Research & Creative Works
No abstract provided.
High Order Orthogonal Tensor Networks: Information Capacity And Reliability, Donald C. Wunsch, Y. M. Mirkes, Alexander N. Gorban
High Order Orthogonal Tensor Networks: Information Capacity And Reliability, Donald C. Wunsch, Y. M. Mirkes, Alexander N. Gorban
Electrical and Computer Engineering Faculty Research & Creative Works
Neural networks based on construction of orthogonal projectors in the tensor power of space of signals are described. A sharp estimate of their ultimate information capacity is obtained. The number of stored prototype patterns (prototypes) can many times exceed the number of neurons. A comparison with the error control codes is made
Prediction Of Yarn Strength From Fiber Properties Using Fuzzy Artmap, Raonak Zaman, Donald C. Wunsch
Prediction Of Yarn Strength From Fiber Properties Using Fuzzy Artmap, Raonak Zaman, Donald C. Wunsch
Electrical and Computer Engineering Faculty Research & Creative Works
The count-strength-product (CSP) of cotton yarn is a complex function of fiber properties and spinning performance. The traditional way of predicting yarn CSP is using linear multiple regression. The correlation coefficient between actual CSP and predicted CSP obtained from linear regression is almost always less than 0.9. In this paper, we used a Fuzzy ARTMAP network to predict yarn CSP from fiber properties and spinning performance. Fiber properties and spinning data were used as inputs to ARTa, and yarn CSP was used as ARTb input. Our objectives are: better prediction of the quality of the end product, …
Safety Analysis Of Redundant Systems Using Fuzzy Probability Theory, James P. Dunyak, Ihab W. Ssad, Donald C. Wunsch
Safety Analysis Of Redundant Systems Using Fuzzy Probability Theory, James P. Dunyak, Ihab W. Ssad, Donald C. Wunsch
Electrical and Computer Engineering Faculty Research & Creative Works
No abstract provided.
Backpropagation Of Accuracy, Donald C. Wunsch, M. Yu Senashova, Alexander N. Gorban
Backpropagation Of Accuracy, Donald C. Wunsch, M. Yu Senashova, Alexander N. Gorban
Electrical and Computer Engineering Faculty Research & Creative Works
We solve the problem: how to determine maximal allowable errors, possible for signals and parameters of each element of a network, proceeding from the condition that the vector of output signals of the network should be calculated with given accuracy? "Backpropagation of accuracy" is developed to solve this problem
A State Space Modeling And Control Method For Multivariable Smart Structural Systems, Robert Butler, Vittal S. Rao
A State Space Modeling And Control Method For Multivariable Smart Structural Systems, Robert Butler, Vittal S. Rao
Electrical and Computer Engineering Faculty Research & Creative Works
A system identification technique for the derivation of minimal, continuous time state variable models for multivariable smart structural systems is presented. The structural identification technique is based on the measurement of eigenvalues and eigenvectors of the structure. Two sensors are required for each mode included in the structural system model. Unlike computational system identification techniques, the relatively large number of sensors simplifies the identification process making it ideal for systems with several inputs and outputs. Additionally, the identification technique allows the implementation of multi-input multi-output full state feedback controllers with simple analog hardware. The amount of hardware required for the …
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 …
A Voltage Control Strategy For Current-Regulated Pwm Inverters, Oleg Wasynczuk, Scott D. Sudhoff, Tin D. Tran, David H. Clayton, Henry J. Hegner
A Voltage Control Strategy For Current-Regulated Pwm Inverters, Oleg Wasynczuk, Scott D. Sudhoff, Tin D. Tran, David H. Clayton, Henry J. Hegner
Electrical and Computer Engineering Faculty Research & Creative Works
Alternative voltage control strategies for current-regulated PWM inverters are analyzed, including previously established feedforward and feedforward/feedback controllers and a newly proposed decoupling feedback control strategy. The steady-state and dynamic characteristics of each of these control methods are illustrated and compared for a selected inverter design. It is shown that the feedforward controller exhibits steady-state error and an undesirable overshoot of the output voltages during startup. The addition of a feedback loop eliminates the steady-state error and reduces the overshoot; however, the natural response is underdamped regardless of the choice of feedback gains. A decoupling feedback control strategy that eliminates the …
Automated State Model Generation Algorithm For Power Circuits And Systems, O. Wasynczuk, Scott D. Sudhoff
Automated State Model Generation Algorithm For Power Circuits And Systems, O. Wasynczuk, Scott D. Sudhoff
Electrical and Computer Engineering Faculty Research & Creative Works
A new approach of automatically generating state-space models of power circuits and systems is presented. In this approach, the composite system state equations are established algorithmically given the standard node incidence matrix and elementary branch data (e.g. resistances, inductances, back emf's). The resulting state equations can be solved using a variety of numerical techniques or commercially available computer simulation programs. An example system consisting of a three-phase generator and rectifier load is used to illustrate this approach. Experimental verification is also provided. © 1996 IEEE.
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.
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 …
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 …
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 …