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2007

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Articles 571 - 600 of 3831

Full-Text Articles in Engineering

Medium Access Control(Mac) Layer Design And Data Query Processing For Wireless Sensor Networks, Qingchun Ren Sep 2007

Medium Access Control(Mac) Layer Design And Data Query Processing For Wireless Sensor Networks, Qingchun Ren

Electrical Engineering Dissertations - Archive

In this dissertation, there are four main aspects included: energy reservation on MAC layer, secure improvement for DoS attacks on MAC layer, query processing with uncertainty for sensor database systems, and throughput maximization on MAC layer for ultra wideband communication systems. In energy reservation, we proposed asynchronous MAC (A-MAC) protocol and asynchronous schedule-based MAC (ASMAC) protocol. A-MAC and ASMAC protocols are attractive due to their suitabilities for multihop networks and capabilities of removing accumulative clock-drifts without any network synchronization. Moreover, we build a traffic-strength- and network-density-based model to adjust essential algorithm parameters adaptively. In secure problem, we proposed a secure …

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Cascaded H-Bridge Multilevel Inverters -- A Reexamination, Jingsheng Liao, Kai-Tak Wan, Mehdi Ferdowsi Sep 2007

Cascaded H-Bridge Multilevel Inverters -- A Reexamination, Jingsheng Liao, Kai-Tak Wan, Mehdi Ferdowsi

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Multilevel converters have gained popularity in high-power applications due to their low switch voltage stress and modularity. Cascaded H-bridge converters are a promising breed of multilevel converters which generally require several independent dc sources. Recently, existence of a redundant switching state has been utilized to replace the independent voltage sources with capacitors except for the one with the highest voltage level. Redundancy in the charge and discharge modes of the capacitors is assumed to be adequate for their voltage regulation. However, output current of the inverter as well as the time duration of the redundant switching states have been neglected. …

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Mesophilic Digestion Kinetics Of Manure Slurry, Khursheed Karim, K. Thomas Klasson, Sadie R. Drescher, Whitney Ridenour, Abhijeet P. Borole, Muthanna H. Al-Dahhan Sep 2007

Mesophilic Digestion Kinetics Of Manure Slurry, Khursheed Karim, K. Thomas Klasson, Sadie R. Drescher, Whitney Ridenour, Abhijeet P. Borole, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Anaerobic Digestion Kinetics Study of Cow Manure Was Performed at 35°C in Bench-Scale Gas-Lift Digesters (3.78 L Working Volume) at Eight Different Volatile Solids (VS) Loading Rates in the Range of 1.11-5.87 G L-1 Day-1. the Digesters Produced Methane at the Rates of 0.44-1.18 L L-1 Day-1, and the Methane Content of the Biogas Was Found to Increase with Longer Hydraulic Retention Time (HRT). based on the Experimental Observations, the Ultimate Methane Yield and the Specific Methane Productivity Were Estimated to Be 0.42 L CH4 (G vs. Loaded)-1 and 0.45 L CH …

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Analysis Of One-Dimensional And Two-Dimensional Thin Film "Pull-In" Phenomena Under The Influence Of An Electrostatic Potential, Gang Duan, Kai-Tak Wan Sep 2007

Analysis Of One-Dimensional And Two-Dimensional Thin Film "Pull-In" Phenomena Under The Influence Of An Electrostatic Potential, Gang Duan, Kai-Tak Wan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A thin one-dimensional rectangular or two-dimensional axisymmetric film is clamped at the perimeter. an electrostatic potential (V*0) applied to a pad directly underneath the film leads to a "pull-in" phenomenon. the electromagnetic energy stored in the capacitive film-pad dielectric gap is decoupled from the mechanical deformation of the film using the Dugdale-Barenblatt-Maugis cohesive zone approximation. the ratio of film-pad gap (g) to film thickness (h), or γ=g/h, is found to play a crucial role in the electromechanical behavior of the film. Solution spanning a wide range of y is found such that V*0 ∝ γ3/2 for …

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Change In Voltage Distortion Predictions At The Pcc Due To Changing Nonlinear Load Current Profile Using Plant Startup Data, Joy Mazumdar, Frank C. Lambert, Ganesh K. Venayagamoorthy, Ronald G. Harley Sep 2007

Change In Voltage Distortion Predictions At The Pcc Due To Changing Nonlinear Load Current Profile Using Plant Startup Data, Joy Mazumdar, Frank C. Lambert, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

Customer loads connected to electricity supply systems may be broadly categorized as either linear or nonlinear. Nonlinear loads inject harmonics in a power distribution network. The interaction of the nonlinear load harmonics with the network impedances creates voltage distortions at the point of common coupling (PCC) which in turn affects other loads connected to the same PCC. When several nonlinear loads are connected to the PCC, it is difficult to predict mathematically how each nonlinear load is affecting the voltage distortion level at the PCC. Typically, customers with nonlinear loads apply harmonic filtering techniques to clean up their current and …

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The Effects Of Signal And Image Compression Of Sar Data On Change Detection Algorithms, Kiran Shenoy Sep 2007

The Effects Of Signal And Image Compression Of Sar Data On Change Detection Algorithms, Kiran Shenoy

Theses and Dissertations

With massive amounts of SAR imagery and data being collected, the need for effective compression techniques is growing. One of the most popular applications for remote sensing is change detection, which compares two geo-registered images for changes in the scene. While lossless compression is needed for signal compression, the same is not often required for image compression. In almost every case the compression ratios are much higher in lossy compression making them more appealing when bandwidth and storage becomes an issue. This research analyzes different types of compression techniques that are adapted for SAR imagery, and tests these techniques with …

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Bipolar Cascade Vertical Cavity Surface Emitting Lasers For Rf Photonic Link Applications, William J. Siskaninetz Sep 2007

Bipolar Cascade Vertical Cavity Surface Emitting Lasers For Rf Photonic Link Applications, William J. Siskaninetz

Theses and Dissertations

The development and demonstration of bipolar cascade vertical cavity surface emitting lasers is presented. The systematic approach to designing, fabricating, and characterizing the critical tunnel junction, incorporating the tunnel junction into an edge emitting bipolar cascade laser, and finally the transition to a VCSEL structure is detailed. A novel approach prior to growing and characterizing BC VCSELs was to investigate bipolar cascade light emitting diodes which incorporate the microcavity designs and disentangles the VCSEL cavity effects from the microcavity. The best performing p-doped oxide aperture microcavity design was then used as the microcavity for 1-, 2-, and 3-stage BC …

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Energy-Efficient Querying Of Wireless Sensor Networks, Christopher R. Mann Sep 2007

Energy-Efficient Querying Of Wireless Sensor Networks, Christopher R. Mann

Theses and Dissertations

Due to the distributed nature of information collection in wireless sensor networks and the inherent limitations of the component devices, the ability to store, locate, and retrieve data and services with minimum energy expenditure is a critical network function. Additionally, effective search protocols must scale efficiently and consume a minimum of network energy and memory reserves. A novel search protocol, the Trajectory-based Selective Broadcast Query protocol, is proposed. An analytical model of the protocol is derived, and an optimization model is formulated. Based on the results of analysis and simulation, the protocol is shown to reduce the expected total network …

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Polarimeter Blind Deconvolution Using Image Diversity, David M. Strong Sep 2007

Polarimeter Blind Deconvolution Using Image Diversity, David M. Strong

Theses and Dissertations

This research presents an algorithm that improves the ability to view objects using an electro-optical imaging system with at least one polarization sensitive channel in addition to the primary channel. An innovative algorithm for detection and estimation of the defocus aberration present in an image is also developed. Using a known defocus aberration, an iterative polarimeter deconvolution algorithm is developed using a generalized expectation-maximization (GEM) model. The polarimeter deconvolution algorithm is extended to an iterative polarimeter multiframe blind deconvolution (PMFBD) algorithm with an unknown aberration. Using both simulated and laboratory images, the results of the new PMFBD algorithm clearly outperforms …

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Finite Element Analysis Of Lamb Waves Acting Within A Thin Aluminum Plate, Sejin Han Sep 2007

Finite Element Analysis Of Lamb Waves Acting Within A Thin Aluminum Plate, Sejin Han

Theses and Dissertations

Structural health monitoring (SHM) is an emerging technology that can be used to identify, locate and quantify structural damages before failure. Among SHM techniques, Lamb waves have become widely used since they can cover large areas from one single location. Due to the development of various structural simulation programs, there is increasing interest in whether SHM data obtained from the simulation can be verified by experimentation. The objective of this thesis is to determine Lamb wave responses using SHM models in ABAQUS CAE(a Finite Element Analysis(FEA) program). These results are then compared to experimental results and theoretical predictions under isothermal …

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Flight Dynamic Response Of Hale Aircraft To Kc-135 Flowfield, Amanda J. Devuono Sep 2007

Flight Dynamic Response Of Hale Aircraft To Kc-135 Flowfield, Amanda J. Devuono

Theses and Dissertations

This research effort examines the static effects of a KC-135 flowfield on a flexible winged Sensorcraft model. The KC-135 flowfield data is generated by a vortex lattice code and integrated into Sensorcraft model for analysis. Building on previous research, a refueling situation was modeled to note the effects of the Sensorcraft at varying locations within the flowfield. The Sensorcraft model was analyzed for both rigid and flexible wings as a means of comparision. Flowfield locations of interest were determined and trimmed conditions were computed for each flowfield location. Utilizing the trimmed condition and flowfield locations, the nonlinear set of EOM's …

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Assessment Of The Bill Emerson Memorial Cable-Stayed Bridge Based On Seismic Instrumentation Data, Genda Chen, Dongming Yan, Wenjian Wang, Man Zheng, Louis Ge, Frank Liu Sep 2007

Assessment Of The Bill Emerson Memorial Cable-Stayed Bridge Based On Seismic Instrumentation Data, Genda Chen, Dongming Yan, Wenjian Wang, Man Zheng, Louis Ge, Frank Liu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In this study, both ambient and earthquake data measured from the Bill Emerson Memorial Cable-stayed Bridge are reported and analyzed. Based on the seismic instrumentation data, the vibration characteristics of the bridge are investigated and used to validate a three-dimensional Finite Element (3-D FE) model of the bridge structure. The 3-D model is rigorous and comprehensive, representing realistic dynamic behaviors of the bridge. It takes into account the geometric nonlinear properties caused by cable sagging and soil-foundation-structure interaction in the Illinois approach of the bridge. The FE model is successfully verified and validated by using the natural frequencies and mode …

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Bayesian Estimation Via Sequential Monte Carlo Sampling-Constrained Dynamic Systems, Lixin Lang, Wen-Shiang Chen, Bhavik R. Bakshi, Prem K. Goel, Sridhar Ungarala Sep 2007

Bayesian Estimation Via Sequential Monte Carlo Sampling-Constrained Dynamic Systems, Lixin Lang, Wen-Shiang Chen, Bhavik R. Bakshi, Prem K. Goel, Sridhar Ungarala

Chemical & Biomedical Engineering Faculty Publications

Nonlinear and non-Gaussian processes with constraints are commonly encountered in dynamic estimation problems. Methods for solving such problems either ignore the constraints or rely on crude approximations of the model or probability distributions. Such approximations may reduce the accuracy of the estimates since they often fail to capture the variety of probability distributions encountered in constrained linear and nonlinear dynamic systems. This article describes a practical approach that overcomes these shortcomings via a novel extension of sequential Monte Carlo (SMC) sampling or particle filtering. Inequality constraints are imposed by accept/reject steps in the algorithm. The proposed approach provides samples representing …

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Resolution Investigation Of A Ratiometric Wavelength Measurement System, Qian Wang, Ginu Rajan, Pengfei Wang, Gerald Farrell Sep 2007

Resolution Investigation Of A Ratiometric Wavelength Measurement System, Qian Wang, Ginu Rajan, Pengfei Wang, Gerald Farrell

Articles

Theoretical analysis and experimental investigations are presented on the resolution of a ratiometric wavelength measurement system. Theoretical modeling indicates that the resolution of a ratiometric wavelength measurement system is determined by the signal-to-noise ratio of the input signal and the noise of the photodetectors associated with optical-to-electronic conversion. For experimental verification, a ratiometric system employing a macrobending standard single-mode fiber is developed and corresponding results are in good agreement with the theoretical prediction.

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Analysis Of Procurement Processes And Development Of Recommendations For Intelligent Transportation Systems (Its) Procurements, Joseph D. Crabtree, Christopher W. Frost, Jennifer Walton, John Crossfield Sep 2007

Analysis Of Procurement Processes And Development Of Recommendations For Intelligent Transportation Systems (Its) Procurements, Joseph D. Crabtree, Christopher W. Frost, Jennifer Walton, John Crossfield

Kentucky Transportation Center Research Report

Traditional state procurement processes are not well-suited to the procurement of Intelligent Transportation Systems (ITS). The objective of this study was to analyze Kentucky’s existing procurement processes, identify strengths and weaknesses of each, and develop recommendations for a revised process (or processes) that would meet the unique requirements of ITS procurements. Four existing processes were identified, studied, documented, and assessed. The study also looked at design-build processes, both in Kentucky and in other states. Recommendations were developed for statutory changes to improve Kentucky’s ability to procure ITS technologies and systems.

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Analysis Of Traffic Crash Data In Kentucky (2002 - 2006), Eric R. Green, Kenneth R. Agent, Jerry G. Pigman Sep 2007

Analysis Of Traffic Crash Data In Kentucky (2002 - 2006), Eric R. Green, Kenneth R. Agent, Jerry G. Pigman

Kentucky Transportation Center Research Report

This report documents an analysis of traffic crash data in Kentucky for the years of 2002 through 2006. A primary objective of this study was to determine average crash statistics for Kentucky highways. Average and critical numbers and rates of crashes were calculated for various types of highways in rural and urban areas. These data can be used in Kentucky’s procedure to identify locations that have abnormal rates or numbers of crashes. The other primary objective of this study was to provide data that can be used in the preparation of the problem identification portion of Kentucky’s Annual Highway Safety …

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Evaluation Of Us 119 Pine Mountain Safety Improvements (Final Report), Jerry G. Pigman, Kenneth R. Agent Sep 2007

Evaluation Of Us 119 Pine Mountain Safety Improvements (Final Report), Jerry G. Pigman, Kenneth R. Agent

Kentucky Transportation Center Research Report

The Transportation Center at the University of Kentucky was requested to perform an evaluation of the safety improvement project over a 7.1-mile section of US 119 on the Whitesburg side of Pine Mountain in Letcher County to determine whether the types of improvements undertaken affected the overall safety of the roadway. Specific attention was given to the effects of a ban on truck traffic that was implemented in March 2001. In addition, there was a need to determine if the use of flexible design was successful after removal of the truck restriction by permitting trucks with dimensions up to the …

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Developing A Byproduct Materials Information Systems For The Kentucky Transportation Cabinet, David Q. Hunsucker, Justin Jones, Tom Hopkins, Charlie Sun Sep 2007

Developing A Byproduct Materials Information Systems For The Kentucky Transportation Cabinet, David Q. Hunsucker, Justin Jones, Tom Hopkins, Charlie Sun

Kentucky Transportation Center Research Report

Kentucky has numerous coal-fired, electric generating facilities and, as a result, there are abundant byproduct materials being produced from these facilities that have environmental, engineering, and economic potential as materials for use in common highway construction and maintenance related activities throughout the Commonwealth. Other byproduct materials are being produced and are available that may have potential uses as well. Although large quantities of byproduct materials are produced in Kentucky and many of those materials have positive or neutral environmental impacts and excellent engineering properties, a formal regulatory framework for selecting, characterizing, recovering, and recycling these material types does not exist. …

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Receiver Operating Characteristic And Location Analysis Of Simulated Near-Infrared Tomography Images, Xiaomei Song, Brian W. Pogue, Hamid Dehghani, Shudong Jiang, Keith D. Paulsen, Tor D. Tosteson Sep 2007

Receiver Operating Characteristic And Location Analysis Of Simulated Near-Infrared Tomography Images, Xiaomei Song, Brian W. Pogue, Hamid Dehghani, Shudong Jiang, Keith D. Paulsen, Tor D. Tosteson

Dartmouth Scholarship

Receiver operating characteristic (ROC) analysis was performed on simulated near-infrared tomography images, using both human observer and contrast-to-noise ratio (CNR) computational assessment, for application in breast cancer imaging. In the analysis, a nonparametric approach was applied for estimating the ROC curves. Human observer detection of objects had superior capability to localize the presence of heterogeneities when the objects were small with high contrast, with a minimum detectable threshold of CNR near 3.0 to 3.3 in the images. Human observers were able to detect heterogeneities in the images below a size limit of 4 mm, yet could not accurately find the …

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Plug-In Hybrid Vehicles -- A Vision For The Future, Mehdi Ferdowsi Sep 2007

Plug-In Hybrid Vehicles -- A Vision For The Future, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

One of the unique advantages of plug-in hybrid vehicles is their capability to integrate the transportation and electric power generation sectors in order to improve the efficiency, fuel economy, and reliability of both systems. This goal is performed via integration of the onboard energy storage units of plug-in vehicles with the power grid by power electronic converters and communication systems. Employing energy storage systems improves the efficiency and reliability of the electric power generation, transmission, and distribution. Similarly, combining an energy storage system with the power train of a conventional vehicle results in a hybrid vehicle with higher fuel efficiency. …

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Multiaxial Thermo-Mechanical Fatigue On Material Systems For Gas Turbines, M. Bartsch, B. Baufeld, M. Henzelmann, Anette M. Karlsson, S. Dalkilic, L. Chernova Sep 2007

Multiaxial Thermo-Mechanical Fatigue On Material Systems For Gas Turbines, M. Bartsch, B. Baufeld, M. Henzelmann, Anette M. Karlsson, S. Dalkilic, L. Chernova

Mechanical Engineering Faculty Publications

Material systems made from nickel based superalloys with protective coatings have been tested in thermo-mechanical fatigue with superposed thermal gradients, which generated multiaxial stress states. The testing conditions were selected for simulating the fatigue loading in the wall of an internally cooled gas turbine blade of an aircraft engine. After thermo-mechanical testing the damage behaviour of the materials has been investigated by means of microscopic methods. The laboratory experiments have been accompanied by numerical simulations. Based on the results of the simulations and observed damage features the test parameters in subsequent laboratory tests have been controlled to facilitate the validation …

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Fluvial Geomorphologic And Hydrodynamic Assessment In The Tidal Portion Of The Lower Rio Grande River, Us-Mexico Borderland, Andrew Ernest, B. Bokhim, N. B. Chang, I. J. Huang Sep 2007

Fluvial Geomorphologic And Hydrodynamic Assessment In The Tidal Portion Of The Lower Rio Grande River, Us-Mexico Borderland, Andrew Ernest, B. Bokhim, N. B. Chang, I. J. Huang

Civil Engineering Faculty Publications

With fast population growth and economic development in the US-Mexico Borderland, water diversion and usages has reduced the flow substantially in the Low Rio Grande River (LRGR). Tidal portion of the LRGR has posed an environmental drought issue since 1993 and the channel clogged with the invasion of non-native plants also causes environmental problems. As a result of the intensity of these natural and manmade factors, the Rio Grande stopped flowing to the sea in February 2001. The flows were reduced to a point that they were unable to push out the sand deposited at the mouth. Geomorphologic evolution in …

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Investigation Into The Possible Use Of An Oxygen Ion Transport Membrane Combustion Unit In An Oxyfired Power Plant, Kirsten Foy Sep 2007

Investigation Into The Possible Use Of An Oxygen Ion Transport Membrane Combustion Unit In An Oxyfired Power Plant, Kirsten Foy

Doctoral

It is generally recognised that carbon dioxide (CO2) emissions damage the environment. Carbon capture and storage offers the possibility of using fossil fuels for power production without releasing C02. In the proposed ZEITMOP power plant cycle hydrocarbon fuel is burned in a mixture of oxygen and C02, allowing easy separation of combustion products to capture the C02 for sequestration. Oxygen ion transport membranes (OTMs) provide oxygen. The original configuration of the cycle requires an OTM air separation unit, in which oxygen is separated from air and mixed with CO2, and a separate combustion chamber, in which fuel is burned in …

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Increased Performance Of Battery Packs By Active Equalization, Jonathan W. Kimball, Brian T. Kuhn, Philip T. Krein Sep 2007

Increased Performance Of Battery Packs By Active Equalization, Jonathan W. Kimball, Brian T. Kuhn, Philip T. Krein

Electrical and Computer Engineering Faculty Research & Creative Works

Battery packs for most applications are series strings of electrochemical cells. Due to manufacturing variations, temperature differences, and aging, the individual cells perform differently. When a complete pack is charged and discharged as a single two-terminal circuit element, some cells are chronically overcharged, undercharged, or overdischarged, all of which act to reduce cell life. The performance and life of the complete pack is limited by the weakest cell. Many methods have been proposed and explored to mitigate this problem. In the present work, a switched-capacitor converter is shown to be a simple and effective method to maintain equal cell or …

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Self-Healing Control With Multifunctional Gate Drive Circuits For Power Converters, Peng Xiao, Ganesh K. Venayagamoorthy, Keith Corzine, Robert S. Woodley Sep 2007

Self-Healing Control With Multifunctional Gate Drive Circuits For Power Converters, Peng Xiao, Ganesh K. Venayagamoorthy, Keith Corzine, Robert S. Woodley

Electrical and Computer Engineering Faculty Research & Creative Works

Many commercial and military transport systems have fault diagnostic functions implemented to help protect the device when a severe fault occurs. However, most present systems do not contain prognostics capability which would allow operators to observe an unhealthy system component in its pre- fault condition. In industry applications, scheduled downtime can result in considerable cost avoidance. The next technology step is self-healing system components which observe not only potential problems, but can also take steps to continue operation under abnormal conditions - whether due to long-term normal wear-and-tear or sudden combat damage. In this paper, current and voltage information using …

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Robust Tuning Of Modern Power System Stabilizers Using Bacterial Foraging Algorithm, B. Sumanbabu, S. Mishra, B. K. Panigrahi, Ganesh K. Venayagamoorthy Sep 2007

Robust Tuning Of Modern Power System Stabilizers Using Bacterial Foraging Algorithm, B. Sumanbabu, S. Mishra, B. K. Panigrahi, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

IEEE Std 421.5, revised by the IEEE excitation system subcommittee introduced a new type of power system stabilizer model, the multiband power system stabilizers (IEEE PSS4B). Although it requires two input signals, like the widely used IEEE PSS2B, the underlying principle of the new IEEE PSS4B makes it sharply different. This paper presents a method based on Bacterial Foraging Algorithm (BFA) to simultaneously tune these modern power system stabilizers (PSSs) in multimachine power system. Simulation results of multi-machine power system validate the efficiency of this approach. the proposed method is effective for the tuning of multi-controllers in large power systems.

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A Memetic Algorithm Configured Via A Problem Solving Environment For The Hamiltonian Cycle Problems, X. S. Chen, Meng-Hiot Lim, Donald C. Wunsch Sep 2007

A Memetic Algorithm Configured Via A Problem Solving Environment For The Hamiltonian Cycle Problems, X. S. Chen, Meng-Hiot Lim, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

Algorithm Development Environment for Permutation-based problems (ADEP) is a software environment for configuring meta-heuristics for solving combinatorial optimization problems. This paper describes the key features of ADEP and how the environment was used to generate a Memetic Algorithm (MA) solution for Hamiltonian Cycle Problems (HCP). The effectiveness of the MA algorithm is demonstrated through computer simulations and its performance is compared with backtracking and other heuristic techniques such as Simulated Annealing, Tabu Search, and Ant Colony Optimization.

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Defect-Tolerant Gate Macro Mapping & Placement In Clock-Free Nanowire Crossbar Architecture, Ravi Bonam, Yong-Bin Kim, Minsu Choi Sep 2007

Defect-Tolerant Gate Macro Mapping & Placement In Clock-Free Nanowire Crossbar Architecture, Ravi Bonam, Yong-Bin Kim, Minsu Choi

Electrical and Computer Engineering Faculty Research & Creative Works

Recently, we proposed a new clock-free nanowire crossbar architecture based on a delayinsensitive paradigm called Null Convention Logic (NCL). The proposed architecture has simple periodic structure that is suitable for non-deterministic nanoscale assembly and does not require a clock distribution network - so it is intrinsically free from timing-related failure modes. Even though the proposed architecture offers improved manufacturability, it is still not free from defects. This paper elaborates on the different programming techniques to map a given threshold gate macro on a random PGMB (Programmable Gate Macro Block) with predefined dimension. Defect-Aware and Defect Unaware approaches have been considered …

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Quantum Mechanics Of Spin Transfer In Coupled Electron-Spin Chains, C. Y. Kim, Lucian Covaci, Fatih Dogan, Frank Marsiglio Sep 2007

Quantum Mechanics Of Spin Transfer In Coupled Electron-Spin Chains, C. Y. Kim, Lucian Covaci, Fatih Dogan, Frank Marsiglio

Materials Science and Engineering Faculty Research & Creative Works

The manner in which spin-polarized electrons interact with a magnetized thin film is currently described by a semi-classical approach. This in turn provides our present understanding of the spin transfer, or spin torque phenomenon. However, spin is an intrinsically quantum-mechanical quantity. Here, we make the first strides towards a fully quantum-mechanical description of spin transfer through spin currents interacting with a Heisenberg-coupled spin chain. Because of quantum entanglement, this requires a formalism based on the density matrix approach. Our description illustrates how individual spins in the chain time-evolve as a result of spin transfer.

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Reliability Modeling For The Advanced Electric Power Grid, Ayman Z. Faza, Sahra Sedigh, Bruce M. Mcmillin Sep 2007

Reliability Modeling For The Advanced Electric Power Grid, Ayman Z. Faza, Sahra Sedigh, Bruce M. Mcmillin

Electrical and Computer Engineering Faculty Research & Creative Works

The advanced electric power grid promises a self-healing infrastructure using distributed, coordinated, power electronics control. One promising power electronics device, the Flexible AC Transmission System (FACTS), can modify power flow locally within a grid. Embedded computers within the FACTS devices, along with the links connecting them, form a communication and control network that can dynamically change the power grid to achieve higher dependability. The goal is to reroute power in the event of transmission line failure. Such a system, over a widespread area, is a cyber-physical system. The overall reliability of the grid is a function of the respective reliabilities …

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