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2005

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Articles 3421 - 3450 of 3590

Full-Text Articles in Engineering

A Multi-Agent Approach For Solving Optimization Problems Involving Expensive Resources, Hoong Chuin Lau, H. Wang Jan 2005

A Multi-Agent Approach For Solving Optimization Problems Involving Expensive Resources, Hoong Chuin Lau, H. Wang

Research Collection School Of Computing and Information Systems

In this paper, we propose a multi-agent approach for solving a class of optimization problems involving expensive resources, where monolithic local search schemes perform miserably. More specifically, we study the class of bin-packing problems. Under our proposed Fine-Grained Agent System scheme, rational agents work both collaboratively and selfishly based on local search and mimic physics-motivated systems. We apply our approach to a generalization of bin-packing - the Inventory Routing Problem with Time Windows - which is an important logistics problem, and demonstrate the efficiency and effectiveness of our approach.

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Heat Transfer Model For The Ignition Of Metal Powder On A Heated Filament, Trent Stanton Ward Jan 2005

Heat Transfer Model For The Ignition Of Metal Powder On A Heated Filament, Trent Stanton Ward

Theses

The thermal processes leading to ignition of metal powders in environments that experience rapid temperature changes are currently poorly understood. In this research, a methodology for studying and quantification of such processes is developed. In the experimental case study, the ignition temperature of Mg powder coated on the surface of an electrically heated filament is detected optically at different heating rates. To interpret the results, a heat transfer model has been developed for a multilayer powder coating on top of an electrically heated filament. The coating is modeled using a hexagonal close packed geometry and the heat transfer equations are …

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Microwave Permeability Of Co₂ Z Composites, Konstantin Rozanov, Marina Koledintseva, Z. W. Li, L. F. Chen Jan 2005

Microwave Permeability Of Co₂ Z Composites, Konstantin Rozanov, Marina Koledintseva, Z. W. Li, L. F. Chen

Physics Faculty Research & Creative Works

The microwave permittivity and permeability of Co2Z barium ferrite composite samples are measured as functions of frequency and volume fraction of the ferrite. Magnetostatic properties of the bulk ferrite are determined. This allows Snoek's law [J. L. Snoek, Physica 14, 204 (1948)] to be verified by comparing the microwave and magnetostatic Snoek's constants. The modification of Snoek's law for hexagonal ferrites suggested recently by Acher et al. [Phys. Rev. B 62, 11324 (2000)] is also verified. Acher's constant is found from microwave measurements to agree with the value calculated from the magnetostatic properties of bulk ferrite, but microwave and magnetostatic …

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

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

Electrical and Computer Engineering Faculty Research & Creative Works

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

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Anisotropic Diffusion Of N-Butane And N-Decane On A Stepped Surface, Shrijay Subramaniyan, Jee-Ching Wang Jan 2005

Anisotropic Diffusion Of N-Butane And N-Decane On A Stepped Surface, Shrijay Subramaniyan, Jee-Ching Wang

Chemical and Biochemical Engineering Faculty Research & Creative Works

The diffusion of single n-butane and n-decane molecules on a model stepped surface, Pt(655), and on a corresponding flat surface, Pt(111), is investigated using molecular-dynamics simulations and anisotropic united atom model. The surface step on Pt(655) causes the alkane molecules to adsorb on the lower terrace in all-trans conformations with their long molecular axes adjacent and parallel to the step edge, and to diffuse anisotropically along the surface step via a constant wiggly motion without rotation or marked deviation from the parallel adsorption configuration. At relatively high temperatures, the alkane molecules can temporarily break away from the step edge but …

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Image Recognition Systems With Permutative Coding, Ernst M. Kussul, Donald C. Wunsch, Tatiana N. Baidyk Jan 2005

Image Recognition Systems With Permutative Coding, Ernst M. Kussul, Donald C. Wunsch, Tatiana N. Baidyk

Electrical and Computer Engineering Faculty Research & Creative Works

A feature extractor and neural classifier for image recognition system are proposed. They are based on the permutative coding technique which continues our investigations on neural networks. It permits us to obtain sufficiently general description of the image to be recognized. Different types of images were used to test the proposed image recognition system. It was tested on the handwritten digit recognition problem, the face recognition problem and the shape of microobjects recognition problem. The results of testing are very promising. The error rate for the MNIST database is 0.44% and for the ORL database is 0.1%.

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A Novel Method For Predicting Harmonic Current Injection From Non-Linear Loads Using Neural Networks, Joy Mazumdar, Frank C. Lambert, Ganesh K. Venayagamoorthy, Ronald G. Harley Jan 2005

A Novel Method For Predicting Harmonic Current Injection From Non-Linear Loads Using Neural Networks, Joy Mazumdar, Frank C. Lambert, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

Generation of harmonics and the existence of waveform pollution in power system networks is one of the major problems facing the utilities. This paper proposes a neural network solution methodology for the problem of measuring the actual amount of harmonic current injected into a power network by a nonlinear load. The determination of harmonic currents is complicated by the fact that the supply voltage waveform is distorted by other loads and is rarely a pure sinusoid. A recurrent neural network trained with the backpropagation through time (BPTT) training algorithm is used to find a way of distinguishing between the load …

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Block Phase Correlation-Based Automatic Drift Compensation For Atomic Force Microscopes, Qinmin Yang, Eric W. Bohannan, Jagannathan Sarangapani Jan 2005

Block Phase Correlation-Based Automatic Drift Compensation For Atomic Force Microscopes, Qinmin Yang, Eric W. Bohannan, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

Automatic nanomanipulation and nanofabrication with an Atomic Force Microscope (AFM) is a precursor for nanomanufacturing. In ambient conditions without stringent environmental controls, nanomanipulation tasks require extensive human intervention to compensate for the many spatial uncertainties of the AFM. Among these uncertainties, thermal drift is especially hard to solve because it tends to increase with time and cannot be compensated simultaneously by feedback. In this paper, an automatic compensation scheme is introduced to measure and estimate drift. This information can be subsequently utilized to compensate for the thermal drift so that a real-time controller for nanomanipulation can be designed as if …

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

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

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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The Method Of Auxiliary Sources As An Efficient Numerical Technique For Large 3d Semi Open Structures, R. S. Zaridze, D. G. Kakulia, K. N. Tavzarashvili, David Pommerenke, G. N. Ghvedashvili, Kai Xiao Jan 2005

The Method Of Auxiliary Sources As An Efficient Numerical Technique For Large 3d Semi Open Structures, R. S. Zaridze, D. G. Kakulia, K. N. Tavzarashvili, David Pommerenke, G. N. Ghvedashvili, Kai Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

The method of auxiliary sources (MAS) has been demonstrated as suitable for solution of diffraction and inverse problems in complex 2D large objects. Based on MAS numerical study of 3D RCS, EMC/EMI and SAR problems, related to the EM field resonance enhancement inside vehicles and the interaction of the cellular telephone radiation with the user''s head are given in other work. The objective of this paper is to present details of MAS application to the wide 3D electrodynamic problems. The area of its efficient application, some features and advantages to achieving efficient solutions, are discussed. The extension of the MAS …

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

Trends In Process Control Systems Security, Ann K. Miller

Electrical and Computer Engineering Faculty Research & Creative Works

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

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Comparison Of Non-Uniform Optimal Quantizer Designs For Speech Coding With Adaptive Critics And Particle Swarm, Wenwei Zha, Ganesh K. Venayagamoorthy Jan 2005

Comparison Of Non-Uniform Optimal Quantizer Designs For Speech Coding With Adaptive Critics And Particle Swarm, Wenwei Zha, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents the design of a companding non-uniform optimal scalar quantizer for speech coding. The quantizer is designed using two neural networks to perform the nonlinear transformation. These neural networks are used in the front and back ends of a uniform quantizer. Two approaches are presented in this paper namely adaptive critic designs (ACD) and particle swarm optimization (PSO), aiming to maximize the signal to noise ratio (SNR). The comparison of these optimal quantizer designs over bit rate range of 3 to 6 is presented. The perceptual quality of the coding is evaluated by the International Telecommunication Union''s Perceptual …

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Effective Strategies For Choosing And Locating Printed Circuit Board Decoupling Capacitors, Todd H. Hubing Jan 2005

Effective Strategies For Choosing And Locating Printed Circuit Board Decoupling Capacitors, Todd H. Hubing

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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Wide Area Power System Protection Using A Learning Vector Quantization Network, Ganesh K. Venayagamoorthy, Mahyar Zarghami Jan 2005

Wide Area Power System Protection Using A Learning Vector Quantization Network, Ganesh K. Venayagamoorthy, Mahyar Zarghami

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a wide area monitoring and protection technique based on a learning vector quantization (LVQ) neural network. Phasor measurements of the power network buses are monitored continuously by a LVQ network in order to alert the control room operators of possible faults. The proposed scheme could be used in a wide area monitored network to provide remedial action when primary local protection schemes for transmission lines fail to function. This technique could also be extended to the actuation of the secondary protection schemes, hence, preserving the integrity of the power network especially when the faults are spreading over …

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The Influence Of Ammonia And Carbon Dioxide On The Sorption Of A Basic Organic Pollutant To A Mineral Surface, Maneerat Ongwandee, Glenn Morrison, S. S. Bettinger Jan 2005

The Influence Of Ammonia And Carbon Dioxide On The Sorption Of A Basic Organic Pollutant To A Mineral Surface, Maneerat Ongwandee, Glenn Morrison, S. S. Bettinger

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Indoor surfaces have a sorptive capacity for organic pollutants which may be significantly influenced by other gases and the pH of the surface. in this research, we examine the influence of a common indoor gaseous acid, CO2, and base, NH3, on the adsorption of a volatile organic base, trimethylamine (TMA), to a mineral surface, zirconium silicate beads. Varying ammonia and CO2 within concentration ranges of indoor relevance substantially influences the sorptive capacity of this mineral surface. Increasing the CO2 mixing ratio to 1000 p.p.m. enhances surface capacity of TMA by 40-50%; increasing the NH3 …

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Spatial Bioaccumulation Modeling In A Network Of Bayous, Ronaldo Luna, Karen H. Watanabe, Andrew J. Wilding Jan 2005

Spatial Bioaccumulation Modeling In A Network Of Bayous, Ronaldo Luna, Karen H. Watanabe, Andrew J. Wilding

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A software system, Spatial Network Bioaccumulation Model (SNBM), was developed to model the bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) in aquatic food webs. The SNBM uses a geographic information system as an engine to: (i) store the spatial representation of input parameters (the data related to the ecosystem), (ii) transfer input and output data to and from the food-web bioaccumulation model, and (iii) display the predicted food-web organism concentrations over a base map of the field site. The bioaccumulation model is a time-dependent, set of first-order ordinary differential equations that are solved numerically. Many sampling locations can be analyzed using …

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Aggregate Gradation Optimization -- Literature Search, David Newton Richardson Jan 2005

Aggregate Gradation Optimization -- Literature Search, David Newton Richardson

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

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Engineered Struvite Precipitation: Impacts Of Component-Ion Molar Ratios And Ph, Jun Wang, Joel Gerard Burken, Xiaoqi Zhang, Rao Y. Surampalli Jan 2005

Engineered Struvite Precipitation: Impacts Of Component-Ion Molar Ratios And Ph, Jun Wang, Joel Gerard Burken, Xiaoqi Zhang, Rao Y. Surampalli

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Struvite precipitation has the potential for removing and recovering phosphorus from agricultural wastewater streams, such as concentrated animal feeding operations wastewater. However, impacts of anticipated component-ion molar ratios and potentially interfering ions are unknown as are the compounding pH relationship with respect to all potential complexes. This research experimentally investigates and mathematically models these factors. Emphasis is placed upon the composition of formed deposits and model validation with experimental data. Results show that calcium is a major interfering ion affecting the deposit composition, decreasing struvite purity. X-ray diffraction (XRD) and scanning electron microscopy + energy dispersive spectrometry were used to …

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Phase Distribution In A High Pressure Slurry Bubble Column Via A Single Source Computed Tomography, Novica Rados, Ashfaq Shaikh, Muthanna H. Al-Dahhan Jan 2005

Phase Distribution In A High Pressure Slurry Bubble Column Via A Single Source Computed Tomography, Novica Rados, Ashfaq Shaikh, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Due to their Numerous Advantages, Slurry Bubble Column Reactors (SBCR) Are Gaining Wide Importance in the Petroleum, Petrochemical, Chemical, and Biochemical Industries. Most Previous Literature Studies on the Fluid Dynamics and the Phase Holdup Distribution in SBCR Are Limited to Low Superficial Gas Velocity, Low Solids Loading, and the Atmospheric Pressure. Moreover, the Presence of a Solids Phase Poses Difficulties in Probe Measurement Techniques Such as Pitot Tube and Optical Probe and See through Measurement Techniques Such as Particle Image Velocimetry (PIV), Laser Doppler Velocimetry (LDV). Single Source Γ-Ray Computed Tomography (CT) Has Been Used to Measure Cross-Sectional Phase Holdup …

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Flow Distribution Characteristics Of A Gas-Liquid Monolith Reactor Using Computed Tomography, Shaibal Roy, Muthanna H. Al-Dahhan Jan 2005

Flow Distribution Characteristics Of A Gas-Liquid Monolith Reactor Using Computed Tomography, Shaibal Roy, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Flow Distribution Characteristics Were Investigated and Quantified in a 0.05 M Diameter Monolith Reactor, Operated Co-Current Downward in the Taylor Flow Regime, using Gamma Ray Computed Tomography (CT). the Flow Conditions Were Selected to Operate the Reactor in the Taylor Flow Regime and to Bracket Some Commercially Viable Operating Conditions for Such Reactors. Various Operating Parameters Were Evaluated for their Effect on the Degree of Flow Non-Uniformity in the Monolith Crosssection. the Results Show that within the Range of Gas and Liquid Superficial Velocities Investigated, There Exists a Window of Operating Conditions (Intermediate Gas and Liquid Velocities) Which Corresponds to …

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Infrastructure Roots: Evolution Of Electric Power In The United States, Mariesa Crow Jan 2005

Infrastructure Roots: Evolution Of Electric Power In The United States, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

Electricity holds a unique place in the US infrastructure. It is a commodity, a technology, and a necessity. Electric utilities must walk a fine line to balance each of these aspects. While electricity is a commodity that may be bought and sold, it must also be regulated to remain affordable for the general population. Reliability is continually balanced against the cost of upgrades and maintenance. This paper discusses the interconnection of regional area power systems in the US and the benefits such interconnection brings.

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Manpower Development: Industry And Educators Need To Work Together, Peter W. Sauer, Mani Venkata, Mariesa Crow Jan 2005

Manpower Development: Industry And Educators Need To Work Together, Peter W. Sauer, Mani Venkata, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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Measuring Scalability Of Resource Management Systems, A. Mitra, Muthucumaru Maheswaran, Shoukat Ali Jan 2005

Measuring Scalability Of Resource Management Systems, A. Mitra, Muthucumaru Maheswaran, Shoukat Ali

Electrical and Computer Engineering Faculty Research & Creative Works

Scalability refers to the extent of configuration modifications over which a system continues to be economically deployable. Until now, scalability of resource management systems (RMSs) has been examined implicitly by studying different performance measures of the RMS designs for different parameters. However, a framework is yet to be developed for quantitatively evaluating scalability to unambiguously examine the trade-offs among the different RMS designs. In this paper, we present a methodology to study scalability of RMSs based on overhead cost estimation. First, we present a performance model for a managed distributed system (e.g., Grid computing system) that separates the manager and …

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Neural Network -Based Nearly Optimal Hamilton-Jacobi-Bellman Solution For Affine Nonlinear Discrete-Time Systems, Jagannathan Sarangapani, Zheng Chen Jan 2005

Neural Network -Based Nearly Optimal Hamilton-Jacobi-Bellman Solution For Affine Nonlinear Discrete-Time Systems, Jagannathan Sarangapani, Zheng Chen

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we consider the use of nonlinear networks towards obtaining nearly optimal solutions to the control of nonlinear discrete-time systems. The method is based on least-squares successive approximation solution of the Generalized Hamilton-Jacobi-Bellman (HJB) equation. Since successive approximation using the GHJB has not been applied for nonlinear discrete-time systems, the proposed recursive method solves the GHJB equation in discrete-time on a well-defined region of attraction. The definition of GHJB, Pre-Hamiltonian function, HJB equation and method of updating the control function for the affine nonlinear discrete time systems are proposed. A neural network is used to approximate the GHJB …

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Neural Networks Based Non-Uniform Scalar Quantizer Design With Particle Swarm Optimization, Wenwei Zha, Ganesh K. Venayagamoorthy Jan 2005

Neural Networks Based Non-Uniform Scalar Quantizer Design With Particle Swarm Optimization, Wenwei Zha, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

Quantization is a crucial link in the process of digital speech communication. Non-uniform quantizer such as the logarithm quantizers are commonly used in practice. In this paper, a companding non-uniform quantizer is designed using two neural networks to perform the nonlinear transformation. Particle swarm optimization is applied to find the weights of neural networks such that the signal to noise ratio (SNR) is maximized. Simulation results on different speech samples are presented and the proposed quantizer design is compared with the logarithm quantizer for bit rates ranging from 3 to 8.

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An Embedded Real-Time Neuro-Fuzzy Controller For Mobile Robot Navigation, Nian Zhang, Daryl G. Beetner, Donald C. Wunsch, B. Hemmelman, Ahmad Hasan Jan 2005

An Embedded Real-Time Neuro-Fuzzy Controller For Mobile Robot Navigation, Nian Zhang, Daryl G. Beetner, Donald C. Wunsch, B. Hemmelman, Ahmad Hasan

Electrical and Computer Engineering Faculty Research & Creative Works

A reactive fuzzy logic based control strategy was developed for mobile robot navigation. To decrease the number of fuzzy rules and related processing, a RAM-based neural network was combined with the fuzzy logic strategy. The fuzzy rules are used to interpret sensor information. The neural network uses results from the fuzzy logic as well as environmental information to make navigation decisions. The feasibility of this neuro-fuzzy approach was demonstrated on a mobile robot using a simple, 8-bit microcontroller. Experiments show the approach works well, as the robot was able to successfully avoid objects while seeking a goal in real-time. The …

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Matched Filter Bound Of Wireless Systems Over Frequency Selective Channels With Receiver Timing Phase Offset, Jingxian Wu, Y. Rosa Zheng, Khaled Ben Letaief, Chengshan Xiao Jan 2005

Matched Filter Bound Of Wireless Systems Over Frequency Selective Channels With Receiver Timing Phase Offset, Jingxian Wu, Y. Rosa Zheng, Khaled Ben Letaief, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

The sampler timing (phase) sensitivity of wireless communication systems is discussed in this paper. Based on the matched filter bound technique, a tight error performance bound is derived for systems experiencing frequency selective Rayleigh fading, with the receiver timing offset being quantified in the error performance expressions. With the error performance bound, the timing phase sensitivity of systems with both symbol spaced receivers and fractionally spaced receivers is analyzed. Simulation results show that the new bound can accurately predict the performance of practical communication systems suffering both frequency selective fading and timing phase offset.

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Model For Estimating Radiated Emissions From A Printed Circuit Board With Attached Cables Due To Voltage-Driven Sources, Todd H. Hubing, Hwan-Woo Shim Jan 2005

Model For Estimating Radiated Emissions From A Printed Circuit Board With Attached Cables Due To Voltage-Driven Sources, Todd H. Hubing, Hwan-Woo Shim

Electrical and Computer Engineering Faculty Research & Creative Works

Common-mode currents induced on cables attached to printed circuit boards (PCBs) can be a significant source of unintentional radiated emissions. This paper develops a model for estimating the amount of common-mode cable current that can be induced by the signal voltage on microstrip trace structures or heatsinks on a PCB. The model employs static electric field solvers or closed-form expressions to estimate the effective self-capacitances of the board, trace, and/or heatsink. These capacitances are then used to determine the amplitude of an equivalent common-mode voltage source that drives the attached cables. The model shows that these voltage-driven common-mode cable currents …

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Analysis Of A Low-Pass Filter Employing A 4-Pin Capacitor, A. Ritter, Todd H. Hubing, Thomas Van Doren, Theodore M. Zeeff Jan 2005

Analysis Of A Low-Pass Filter Employing A 4-Pin Capacitor, A. Ritter, Todd H. Hubing, Thomas Van Doren, Theodore M. Zeeff

Electrical and Computer Engineering Faculty Research & Creative Works

Capacitors with two or three leads tend to make poor low-pass filters at high frequencies (e.g. greater than 100 MHz) due to the mutual inductance between the input and output sides of the filter. This work proposes a four-lead low-pass filter capacitor design that minimizes the magnetic flux coupling between the input and output. Measurements of a prototype capacitor confirm that it performs significantly better than a typical two-lead capacitor at high frequencies.

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Adaptive Replication And Access Control Of Multimedia Data In A P2p Environment, Sanjay Kumar Madria, Sanjeev Agarwal Jan 2005

Adaptive Replication And Access Control Of Multimedia Data In A P2p Environment, Sanjay Kumar Madria, Sanjeev Agarwal

Computer Science Faculty Research & Creative Works

This paper explores some of the ideas and solutions related to replication and access control of multimedia data in a hierarchical P2P environment. We provided overview of the techniques to generate multiresolution of multimedia data and explored error recovery and access control issues.

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