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Composition - Microstructure - Property Relationships In Dual Phase Bulk Magnetoelectric Composite, Rashed Adnan Islam May 2008

Composition - Microstructure - Property Relationships In Dual Phase Bulk Magnetoelectric Composite, Rashed Adnan Islam

Material Science and Engineering Dissertations - Archive

The coexistence of coupled electrical and magnetic properties in the “magnetoelectric” material has led to the possibility of developing smarter and smaller electronic components. In order to make this possibility a reality, significant efforts are required to understand the science of magnetoelectric (ME) behavior and apply this understanding to develop higher sensitivity material. The primary aims of this thesis are to identify the role of composition, microstructural variables, composite geometry, texturing, post sintering heat treatment, and nanoscale assembly on ME coefficient. The overall objective is to synthesize, characterize and utilize a high ME coefficient composite. The desired range of ME …

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Voltage Profile Estimation And Reactive Power Control Of Distribution Feeders, David Timothy Chessmore May 2008

Voltage Profile Estimation And Reactive Power Control Of Distribution Feeders, David Timothy Chessmore

Electrical Engineering Dissertations - Archive

Distribution systems are important transportation links for the delivery of electric power. Understanding the system conditions of distribution feeders is vital for controlling power systems and maintaining electricity flow on power grids. With better knowledge of the system conditions on distribution feeders, a deliberate and systematic approach can be taken to achieve more efficient and reliable power delivery. Furthermore, better understanding of system conditions can be useful in reducing operation and maintenance costs in various power system applications such as voltage control and capacitor bank switching. This dissertation presents a novel method for estimating the voltage profile of a radial …

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Simultaneous Robot Localization And Mapping Of Parameterized Spatio-Temporal Fields Using Multi-Scale Adaptive Sampling, Muhammad Faizan Mysorewala May 2008

Simultaneous Robot Localization And Mapping Of Parameterized Spatio-Temporal Fields Using Multi-Scale Adaptive Sampling, Muhammad Faizan Mysorewala

Electrical Engineering Dissertations - Archive

This dissertation presents a Multi-scale Adaptive Sampling (AS) framework for combining measurements arriving from mobile robotic sensors of different scales, rates and accuracies, in order to reconstruct a parametric spatio-temporal field. The proposed sampling algorithm, "EKF-NN-GAS", is based on the Extended Kalman Filter (EKF), Radial Basis Function (RBF) Neural Networks and Greedy Search Heuristics. This novel AS algorithm responds to real-time measurements by continuously directing robots to locations most likely to yield maximum information about the sensed field. EKF is used to derive quantitative information measures for sampling locations. In addition, the localization uncertainty of the robots is minimized by …

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The Application Of Discrete-Event Simulation For Demining Strategy Evaluation, Hui-Chiao Jen May 2008

The Application Of Discrete-Event Simulation For Demining Strategy Evaluation, Hui-Chiao Jen

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Teams of mobile autonomous robots have been proposed for the detection and clearing of landmines. Several competing strategies for automated mine detection have been proposed. This paper will discuss the development of a tool that will support the quantitative analysis of various automated mine detection approaches used in Humanitarian Demining and Military Mine Field Breaching. The approaches used to model mine detection in a scout, breaching, and Humanitarian Demining scenario using a discrete-event simulation analysis tool are discussed. The model assumes that each UGV is autonomous rather than being directly controlled by a centralized command and control system. The algorithm …

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Passivation Of Si (100) Surface And Fabrication Of Doping-Free Mosfet, Muhammad Yusuf Ali May 2008

Passivation Of Si (100) Surface And Fabrication Of Doping-Free Mosfet, Muhammad Yusuf Ali

Electrical Engineering Dissertations - Archive

Chalcogen atoms have been successfully used for the passivation of GaAs(100) as well as Ge(100) and Si(100) substrates. Unlike GaAs(100) and Ge(100), the native oxide(SiO2) of Si(100) substrate is not soluble in ammonium sulfide solution ((NH4)2Sx) or water, which is a major problem to passivate Si(100) surface in a solution. In this work, a wet chemical process has been developed in which a compatible etchant ammonium hydroxide (NH4OH) is added with a passivating solution ((NH4)2S). Because of the compatibility of the etchant with the passivating solution, native oxide on Si(100) surface is removed in-situ to expose a fresh and clean …

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Mitigation Of Vibration In A Permanent Magnet Synchronous Machine Using Field Reconstruction, Umamaheshwar Krishnamurthy May 2008

Mitigation Of Vibration In A Permanent Magnet Synchronous Machine Using Field Reconstruction, Umamaheshwar Krishnamurthy

Electrical Engineering Dissertations - Archive

Permanent magnet synchronous machines (PMSM) are widely used due to their unique characteristics including high efficiency, high power density, simple construction, simple maintenance, and relative ease of control. With increasing need for automation, survivable and fault tolerant motor drives are highly in demand in many sectors of industry. Advancement in the area of modern power electronics has allowed researchers a great deal of flexibility in implementing complex control routines. While considerable of focus has been placed on improving schemes of control, not much effort has been put improvements in the performance of electric drives. It is also important to note …

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An Influenza Virus Molecular Infection Model And Discrete Event, Stochastic Simulation., Richard Burke Squires May 2008

An Influenza Virus Molecular Infection Model And Discrete Event, Stochastic Simulation., Richard Burke Squires

Computer Science and Engineering Theses - Archive

Influenza virus is responsible for the greatest pandemic in human history causing 20 - 40 million deaths worldwide during the 1918 flu season. In 1997 fears of a future pandemic arose with the discovery of a new strain of H5N1 avian influenza. In an effort to better understand the dynamics of influenza infection a new model of influenza virus infection at the molecular level has been developed. Comprising nineteen stages and five molecular types (mRNA, cRNA, vRNA, vRNP and proteins) the FluSim model consists of the major contributing pathogen factors to influenza infection. A discrete event, stochastic simulation based upon …

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Secure Data Aggregation In Wireless Sensor Networks, Wei Zhang May 2008

Secure Data Aggregation In Wireless Sensor Networks, Wei Zhang

Computer Science and Engineering Dissertations - Archive

Recent advances in micro-electro-mechanical systems (MEMS) technology and wireless communications technologies have enabled the deployment of wireless sensor networks (WSNs) in a plethora of applications, ranging widely from military surveillance to civilian applications. To protect the networks from different kinds of attacks, security in wireless sensor networks plays a crucial role and has received increased attention especially in the applications deployed in hostile environments, such as battlefield monitoring and home security. While extensive efforts have been devoted toward securing conventional networks, the stringent resource constraints, such as energy, communication and computation capability, etc., have often prevented their direct adoptions. As …

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Data Dissemination Protocols In Wireless Sensor Networks : Design, Modeling And Security, Pradip De May 2008

Data Dissemination Protocols In Wireless Sensor Networks : Design, Modeling And Security, Pradip De

Computer Science and Engineering Dissertations - Archive

Wireless sensor and actuator networks have been one of the stepping stones towards realizing a pervasive computing infrastructure. However, in a post-deployment scenario, transferring critical updates and reconfigurations on a network-wide scale is a non-trivial proposition. Wireless techniques provide the only means of communication, and consequently, an in-depth study of the multihop broadcast based communication paradigm and the design of efficient and reliable data dissemination protocols for reprogramming a sensor network is of paramount importance. In this dissertation, we initially focus on the formal modeling and performance analysis of broadcast-based data dissemination protocols in wireless sensor networks. The data propagating …

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Methodology For Reverse Supply Chain Design In Consumer Electronics Industry, Santhanam Rajagopalan May 2008

Methodology For Reverse Supply Chain Design In Consumer Electronics Industry, Santhanam Rajagopalan

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Reverse Logistics (RL), the art and science of moving goods typically from the end consumer towards the upstream end of supply chains, has been the subject of many strategic meetings in organizations today. This is attributed mainly due to the tighter federal environmental legislations on product returns and a hugely untapped potential that has been often overlooked by the managers. Traditionally, enterprises spend most of the improvement initiatives in optimizing its forward supply chain (FSC) performance that aims to delight the end consumer. However, it is not a panacea by itself in the process of continuously satisfying the end customer. …

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Determining The Flow Characteristics Of A Perfusion Device For Donor Heart Transport, Michael Louis Cobert May 2008

Determining The Flow Characteristics Of A Perfusion Device For Donor Heart Transport, Michael Louis Cobert

Bioengineering Theses - Archive

Current technology has limits organ transport for transplantation to static storage, thereby reducing the reasonable distance of travel. Continuous machine perfusion has been proposed as a viable alternative to improving function and outcome. A series of studies with such a device have been developed to elucidate the method by which optimal results can be achieved. Adult mongrel dog hearts were established in a device that provided continuous perfusion of oxygenated fluid and enabled precise control of flow rate, oxygenation, and fluid temperature. The first series of experiments sought to determine an optimal flow rate for tissue perfusion at one of …

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A Symbiotic Relationship Between Mid Century Modern Masters: The Collaborative Works Of Arthur And Marie Berger, Landscape Architects, And O'Neil Ford, Architect, Dianne Susanduffner Laurence Apr 2008

A Symbiotic Relationship Between Mid Century Modern Masters: The Collaborative Works Of Arthur And Marie Berger, Landscape Architects, And O'Neil Ford, Architect, Dianne Susanduffner Laurence

Landscape Architecture Masters & Design Theses - Archive

Landscape Architects Marie and Arthur Berger were partners as well as husband and wife. The pair began practicing in Dallas, Texas after their marriage in 1946. Marie Monica Harbeck graduated from the University of Oregon and Arthur from the University of Kansas and Harvard Graduate School and met while they were sequestered as civilian employees by the Army Engineer Board at Fort Belvoir, Virginia, conducting camouflage research during World War II. After the war and after completing significant projects in Dallas, Texas, such as the DeGolyer Estate at White Rock Lake (now the Dallas Arboretum), the Bergers embarked on a …

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Fabrication Of Fept Ferromagnetic Nanoparticles, Kevin Eugene Elkins Apr 2008

Fabrication Of Fept Ferromagnetic Nanoparticles, Kevin Eugene Elkins

Material Science and Engineering Dissertations - Archive

Fabrication of chemically disordered FePt particles ranging from 2 - 9 nm with a precision of 1 nm has been achieved through modification of key process variables including surfactant concentration, heating rates and the type of iron precursor. In addition, the shape evolution of the FePt nanoparticles during particle growth can be manipulated to give cubic or rod geometries through changes to the surfactant injection sequence and solvent system. The primary method for synthesis of the disordered FePt nanoparticles is the polyol reduction reported by Fievet et al., which has been modified and used extensively for synthesis of diff ering …

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Hierarchical Reinforcement Learning Using Automatic Task Decomposition And Exploration Shaping, Predrag Djurdjevic Apr 2008

Hierarchical Reinforcement Learning Using Automatic Task Decomposition And Exploration Shaping, Predrag Djurdjevic

Computer Science and Engineering Theses - Archive

Reinforcement learning agents situated in real world environments have to be able to address a number of challenges in order to succeed at accomplishing a wide range of tasks over their lifetime. Among these, such systems have to be able to extract control knowledge from already learned tasks and apply them to subsequent ones in order to allow the agent to accomplish the new task faster and to accelerate the learning of an optimal policy. To address skill reuse and skill transfer, a number of approaches using hierarchical state and action spaces have been introduced recently which build on the …

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Flight Data Analysis And Simulation Of Wind Effects During Aerial Refueling, Timothy Allen Lewis Apr 2008

Flight Data Analysis And Simulation Of Wind Effects During Aerial Refueling, Timothy Allen Lewis

Mechanical and Aerospace Engineering Theses - Archive

This thesis presents an analysis of data obtained in an automated aerial refueling test flight conducted with a KC-135 as the tanker and a Learjet 25 as the surrogate receiver UAV. The purpose is to identify the wind induced by the tanker wake and its effect on the receiver aircraft. From the available flight data, a direct computation of the winds experienced by the tanker and receiver is carried out. The mean variation of the receiver wind is compared with the tanker wind when the receiver is at the observation and contact positions. This results in the identification of the …

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Impact Of Lateral Swell Pressure On Retaining Structure Design Using Expansive Cohesive Backfill, Mark G. Thomas Apr 2008

Impact Of Lateral Swell Pressure On Retaining Structure Design Using Expansive Cohesive Backfill, Mark G. Thomas

Civil Engineering Theses - Archive

Since cohesive soils are difficult to drain once becoming saturated, in order to reduce lateral earth pressures exerted by saturated cohesive soils on retaining structures, retaining wall designs most always specify use of drainable granular backfill. However, costs for the importation of granular backfill materials continues to increase due to depletion of these materials in certain areas, and to the ever-increasing costs for material transportation, largely related to increased labor and fuel prices. These factors, together with the costs of removing replaced cohesive materials, and coupled with resource and environmental conservation concerns, are driving efforts to develop reasonable and prudent …

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Closed-Form Development Of A Family Of Higher Order Tetrahedral Elements Through The Fourth Order, Sara Elizabeth Mccaslin Apr 2008

Closed-Form Development Of A Family Of Higher Order Tetrahedral Elements Through The Fourth Order, Sara Elizabeth Mccaslin

Mechanical and Aerospace Engineering Dissertations - Archive

This research is concerned with the development and implementation of a family of tetrahedral elements through the fourth order. The straight-sided tetrahedral elements are developed in closed-form. This work investigates the efficiency of closed-form implementation of stiffness matrices and error estimators compared to numerical implementation. An additional objective is the compaction of closed-form source-code files which require as little storage space as possible, a more pronounced requirement at high p-levels. For the straight-sided elements through p-level 4, the stiffness matrix, equivalent nodal load vectors, and error estimators (based on nodal averaging) are developed using closed-form equations obtained through the use …

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Non-Linear Finite Element Dynamic Analysis Of Tapered Hollow Steel Poles For Passive Base Isolation, Tri Le Apr 2008

Non-Linear Finite Element Dynamic Analysis Of Tapered Hollow Steel Poles For Passive Base Isolation, Tri Le

Civil Engineering Dissertations - Archive

Long tapered poles are commonly used to support Closed Circuit Television (CCTV) Cameras for security and traffic monitoring. Images received from CCTV are normally distorted depending on the wind induced vibration characteristics of the forcing function. To reduce image distortion, three approaches are integrated to optimize the process, which are: (1) development of equations for pole's frequency of vibration in terms of its geometric variables; (2) development of a mechanical damping device to isolate the pole's vibration from that of the camera; and (3) development of an electrical image processing device for image corrections. The identification of a pole's natural …

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Dynamic Properties Of Compacted Soils Using Resonant Column With Self-Contained Bender Elements, Roshnara Mohammad Apr 2008

Dynamic Properties Of Compacted Soils Using Resonant Column With Self-Contained Bender Elements, Roshnara Mohammad

Civil Engineering Theses - Archive

A comprehensive series of resonant column and bender elements tests were simultaneously performed in the developed RC/BE apparatus. RC/BE tests were conducted on compacted specimens of poorly graded sand (SP) and high plasticity clay (CH) prepared at different moisture contents (17.7, 22.1, 25.5, 30.2% by weight for clay, and 5, 10, 15, 20% by weight for sand) and under different confining pressures (0, 2.5, 5.0, and 10.0 psi, or 0, 17.2, 34.4, 69.0 kPa) in order to assess the influence of key environmental factors, such as compaction induced suction and confining pressure, on small-strain stiffness properties of unsaturated soils, such …

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Practical Evaluation And Analysis Of Passive Uhf Rfid Tags, Ananyaa Gautham Apr 2008

Practical Evaluation And Analysis Of Passive Uhf Rfid Tags, Ananyaa Gautham

Electrical Engineering Theses - Archive

In this thesis, we have identified the important parameters that impact the performance of passive UHF RFID tags and developed a testing methodology to evaluate and characterize tags. We have also developed the theory to validate the empirical data and analysis. The high performance, low cost and increased storage capacity of the RFID tags has led to the economic adoption of this technology by many industries. Choosing the right tag for the right application might be quite a task with the number of commercially available tags today. It is very important to test the tags and analyze the results to …

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Texture Measurement And Skid Number Prediction Using Laser Data Acquisition, Digital Signal Processing, And Neural Networks, John Michael Kebrle Apr 2008

Texture Measurement And Skid Number Prediction Using Laser Data Acquisition, Digital Signal Processing, And Neural Networks, John Michael Kebrle

Computer Science and Engineering Theses - Archive

Real-time estimation of the skid number of pavement is difficult. Traditional methods of volumetric measurement are cumbersome and time consuming. It is desired to enable prediction of the skid number of pavement using non-contact means, and to doso using a method which provides a reasonable estimate of the pavements skid number. This research used laser data acquisition of macro-texture, Digital Signal Processing and Neural Networks to estimate the skid number of pavement to a reasonable degree. The research used Digital Signal Processing to identify potentially bad data sets, and a Neural Network model for predicting skid number on the refined …

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Shared Land Use Impacts Between Military Installations And Contiguous Communities (Post-Brac): Fact And Opinion Differences In Planning And Public Policy, Rumanda Kay Young Apr 2008

Shared Land Use Impacts Between Military Installations And Contiguous Communities (Post-Brac): Fact And Opinion Differences In Planning And Public Policy, Rumanda Kay Young

Planning Dissertations - Archive

How a policy or planning tool (e.g. BRAC) contributes to real and perceived conclusions from policy implementation is the main focus of this research. This research examines differences between real and perceived encroachment issues and concerns through study of military installations and their contiguous communities using post-BRAC opinion data compared to conclusions drawn from pre-BRAC and post-BRAC empirical data. A study of six (6) supporting research topics from current literature leads to a hypothesis that there are no differences between the same variables using empirical data (reality) and opinions (perception) with respect to variable descriptors of encroachment in the post-BRAC …

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Web Based Integrated Multiple Function Customer Demand And Budget Management System, Supun Tiptipakorn Apr 2008

Web Based Integrated Multiple Function Customer Demand And Budget Management System, Supun Tiptipakorn

Electrical Engineering Dissertations - Archive

Traditionally, most end-use residential consumers receive flat rate monthly electricity bills based on load profiling rate calculations from different utilities' consumer classes. Those flat rates do not relate and reflect the true and time-varying costs of electricity supply during actual time of consumptions. Without acknowledging the cost differences, consumers do not have any incentive to adjust their load consumption patterns, and inefficiencies of resource allocations can result. Cheaper-cost off-peak load users can end up paying to offset those expensive peak load users. Additionally, peak load users may still consume their loads without any awareness that their power networks may have …

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The Compass Rose Vol. Xxii, No. 1, University Of Texas At Arlington Library Special Collections & Archives Apr 2008

The Compass Rose Vol. Xxii, No. 1, University Of Texas At Arlington Library Special Collections & Archives

The Compass Rose

The purpose of The Compass Rose is to raise awareness of Special Collections' resources and to foster the use of these resources. The newsletter also reports significant new programs, initiatives, and acquisitions of Special Collections. The issues included here are scans of print newsletters from the 1990s and 2000s. Current issues and posts of The Compass Rose can now be accessed on the UTA Libraries Compass Rose Blog.

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Analysis And Optimization Of A Crashworthy Helicopter Seat, Nauman A. L Mhaskar Mar 2008

Analysis And Optimization Of A Crashworthy Helicopter Seat, Nauman A. L Mhaskar

Mechanical and Aerospace Engineering Theses - Archive

The objective of a crashworthy seat is to improve the survivability of occupants (cockpit and cabin) in helicopter crashes. All modern helicopter seats are equipped with an energy absorber to reduce lumbar spine load during crash landing. The main objective of this research is to carry out the structural analysis and optimization of a helicopter crashworthy troop seat assembly using finite element methods. The transient dynamic nonlinear finite element analysis helps in identifying whether the seat structure will survive in a crash landing situation, and optimization helps in reducing the weight of the crashworthy seat. The seat is analyzed using …

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Improving The Bit Error Rate Performance Of Gsm System Using A Independent Component Analysis Based Non-Linear Filter, Kumarabhijeet Singh Mar 2008

Improving The Bit Error Rate Performance Of Gsm System Using A Independent Component Analysis Based Non-Linear Filter, Kumarabhijeet Singh

Electrical Engineering Theses - Archive

Presently, call drop out is considered a major problem in wireless communication. A large percentage of call drops take place due to network congestion, handover failure and high bit error rate.Our main objective is to reduce call drops due to high bit error rate using a newly proposed signal processing block (SPB) at the receiver section of a mobile handset. The SPB helps improve the performance of the wireless system, particularly Global Systems for Mobile (GSM) by providing a coding gain over the existing system. In this work, we carried out a simulation of the physical layer of a GSM …

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Performance Evaluation Of Greedy Heuristic For Sip Analyzer In H.264/Svc, Jaydeep Vijay Inamdar Mar 2008

Performance Evaluation Of Greedy Heuristic For Sip Analyzer In H.264/Svc, Jaydeep Vijay Inamdar

Electrical Engineering Theses - Archive

The latest scalable video coding standard, H.264/SVC uses many components of H.264/AVC standard to maintain backward compatibility and also has proposed many tools to support scalable video coding with increased coding efficiency. SIP Analyzer is one such tool incorporated in JSVM (Joint Scalable Video Model) software which is the reference software for the SVC project. SIP Analyzer implements Selective Interlayer Prediction strategy to encode the bitstream so as to improve coding performance in scenarios where multiple adaptation is not needed without losing much if the same bitstream is used in scenario where multiple adaptation is needed. Core of this algorithm …

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Fast Algorithms For Mdct And Low Delay Filterbanks Used In Audio Coding, Ravi Kiran Chivukula Mar 2008

Fast Algorithms For Mdct And Low Delay Filterbanks Used In Audio Coding, Ravi Kiran Chivukula

Electrical Engineering Theses - Archive

Modern audio and speech coding systems use filterbank and transform coding techniques to decorrelate the input signal. Cosine-modulated, perfect reconstruction, pseudo-QMF filterbanks are most commonly used for this purpose. In this thesis, we present three propositions. First, a fast algorithm for modified discrete cosine transform (MDCT) for transform lengths of the form 5× 2m and 15× 2m is presented. This algorithm is based on mapping the MDCT to DCT-II via DCT-IV and using the involutory property of the DCT-IV matrix. This leads to a reduction in the number of multiplications and constant memory requirement. The algorithm also uses very efficient …

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On Reducing Call Drop Outs By Improving Bit Error Rate Performance In A Gsm Mobile Communications System, Sudeep Sharma Mar 2008

On Reducing Call Drop Outs By Improving Bit Error Rate Performance In A Gsm Mobile Communications System, Sudeep Sharma

Electrical Engineering Theses - Archive

Call Drop Out is one of the most annoying problems in Mobile Communications. It is one of the most important Quality of Service (QoS) indicators for a mobile carrier. Over the years, many strategies have been proposed to solve the problem of call drop out. But the problem is still prevalent. One of the important reasons for call drop outs is high Bit Error Rate (BER). In general, many existing wireless systems set a threshold BER before a call is dropped. In this work, our intent is to reduce the call drop out due to high BER. Towards that end, …

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Enhancing Jswat For Monitor-Based Executions, Arun Ramani Mar 2008

Enhancing Jswat For Monitor-Based Executions, Arun Ramani

Computer Science and Engineering Theses - Archive

Concurrent programs contain more than one thread that executes concurrently to accomplish a particular task. Since the threads in a concurrent program work together to accomplish a common goal, they share the data, code, resources and address space of their process. This reduces the overhead involved in creating and managing the threads but leads to side effects like race conditions, critical section problem and deadlocks. There are several operating system constructs to solve these issues such as locks, semaphores, monitors etc. Locks are associated with each object to control access of shared resources. Semaphores can be described as counters used …

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