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2001

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Articles 331 - 360 of 1795

Full-Text Articles in Engineering

Development Of An Integrated Sensor For The Measurement Of The Acoustic Local Volume Displacement Of Vibrating Beams, Randall Rozema Aug 2001

Development Of An Integrated Sensor For The Measurement Of The Acoustic Local Volume Displacement Of Vibrating Beams, Randall Rozema

Masters Theses

Currently, the methods used for sensing the volume displacement of a vibrating structure entail the use of a polyvinylidene fluoride sensor that spans the entire length of the structure. However, this work shows that the surface behavior related to volume displacement can be measured through the use of a polyvinylidene fluoride sensor that spans only the area of interest. In this application it was shown that two-point sensors are required in addition to the distributed, polyvinylidene fluoride sensor to achieve an accurate measurement. As a result, a set of four beams with different end conditions were constructed so that the …


A General Decomposition For Reversible Logic, Marek Perkowski, Lech Jozwiak, Pawel Kerntopf, Alan Mishchenko, Anas Al-Rabadi, Alan Coppola, Andrzej Buller, Xiaoyu Song, Svetlana Yanushkevich, Vlad P. Shmerko, Malgorzata Chrzanowska-Jeske, Mozammel Huq Azad Khan Aug 2001

A General Decomposition For Reversible Logic, Marek Perkowski, Lech Jozwiak, Pawel Kerntopf, Alan Mishchenko, Anas Al-Rabadi, Alan Coppola, Andrzej Buller, Xiaoyu Song, Svetlana Yanushkevich, Vlad P. Shmerko, Malgorzata Chrzanowska-Jeske, Mozammel Huq Azad Khan

Electrical and Computer Engineering Faculty Publications and Presentations

Logic synthesis for reversible logic differs considerably from standard logic synthesis. The gates are multi-output and the unutilized outputs from these gates are called “garbage”. One of the synthesis tasks is to reduce the number of garbage signals. Previous approaches to reversible logic synthesis minimized either only the garbage or (predominantly) the number of gates. Here we present for the first time a method that minimizes concurrently the number of gates, their total delay and the total garbage. Our method adopts for reversible logic many ideas developed previously for standard logic synthesis (such as Ashenhurst/Curtis Decomposition, Dietmeyer’s Composition, non-linear preprocessing …


Quality Based Prequalification Of Contractors, Donn E. Hancher, Sean E. Lambert, William F. Maloney Aug 2001

Quality Based Prequalification Of Contractors, Donn E. Hancher, Sean E. Lambert, William F. Maloney

Kentucky Transportation Center Research Report

This report summarizes the efforts to provide the Kentucky Transportation Cabinet with a system for evaluating the quality of the performance of contractors on highway construction projects and using that evaluation in the Cabinet’s annual prequalification process for contractors. Contacts with several other state departments of transportation were made to identify best practices and concerns. An advisory committee of experienced KyTC engineers plus Kentucky contractor representatives met extensively to develop the final performance evaluation documents to be used in the process.

A performance evaluation process was developed to evaluate a contractor’s work on projects and the results from all of …


2001 Safety Belt Usage Survey In Kentucky, Kenneth R. Agent, Eric R. Green Aug 2001

2001 Safety Belt Usage Survey In Kentucky, Kenneth R. Agent, Eric R. Green

Kentucky Transportation Center Research Report

The objective of this study was to establish 2001 safety belt and child safety seat usage rates in Kentucky. The 2001 survey continues to document the results after enactment of a statewide mandatory safety belt law in 1994. It also documented the long term results of the Click It or Ticket enforcement campaign which was conducted around Memorial Day. Data were collected at 200 randomly selected sites spread across Kentucky. Data from the individual sites were combined into a statewide percentage considering function classification, geographic region, and vehicle miles traveled.

The data show that the usage rate increase found in …


Evaluation Of Kentucky’S Click It Or Ticket Campaign, Kenneth R. Agent, Eric R. Green Aug 2001

Evaluation Of Kentucky’S Click It Or Ticket Campaign, Kenneth R. Agent, Eric R. Green

Kentucky Transportation Center Research Report

The objective of this report was to document the results of the Click It or Ticket campaign in Kentucky. The campaign involved a combination of earned media, paid media, and enforcement. The earned media started about three weeks prior to Memorial Day 2001 and continued through the enforcement period. The paid media started about two weeks prior to Memorial Day. The enforcement period was a two-week period including the week before and the week of Memorial Day.

The evaluation of the campaign included documenting the activities associated with the program (publicity and enforcement) and evaluating the results. The evaluation involved …


An Emi Estimate For Shielding-Enclosure Evaluation, Min Li, James L. Drewniak, S. Radu, Joe Nuebel, Todd H. Hubing, Richard E. Dubroff, Thomas Van Doren Aug 2001

An Emi Estimate For Shielding-Enclosure Evaluation, Min Li, James L. Drewniak, S. Radu, Joe Nuebel, Todd H. Hubing, Richard E. Dubroff, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

A relatively simple, closed-form expression has been developed to estimate the EMI from shielding enclosures due to coupling from interior sources through slots and apertures at the enclosure cavity modes. A power-balance method, Bethe's (1944) small-hole theory, and empirically developed formulas for the relation between radiation, and slot length and number of slots, were employed to estimate an upper bound on the radiated EMI from shielding enclosures. Comparisons between measurements and estimated field strengths suitably agree within engineering accuracy.


Emi Considerations In Selecting Heat-Sink-Thermal-Gasket Materials, Yu Huang, J. E. Butler, M. De Sorgo, Richard E. Dubroff, Todd H. Hubing, James L. Drewniak, Thomas Van Doren Aug 2001

Emi Considerations In Selecting Heat-Sink-Thermal-Gasket Materials, Yu Huang, J. E. Butler, M. De Sorgo, Richard E. Dubroff, Todd H. Hubing, James L. Drewniak, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

Specific design criteria are proposed to mitigate radiated emissions from a resonant enclosure excited by a heat sink acting as a microstrip patch antenna source. In this particular application, the EMI mechanism is assumed to be due to coupling from the dominant TMz010 mode to one or more resonant modes associated with the enclosure dimensions. The enclosure is then presumed to radiate, at the enclosure resonance frequencies, through one or more apertures, slots, or seams. The EMI-reduction strategy consists of shifting the resonant frequency of the dominant-patch antenna mode by dielectrically loading the patch antenna with thermal-gasket material …


Including Smt Ferrite Beads In Dc Power Bus And High-Speed I/O Line Modeling, Jun Fan, Shaofeng Luan, James L. Drewniak Aug 2001

Including Smt Ferrite Beads In Dc Power Bus And High-Speed I/O Line Modeling, Jun Fan, Shaofeng Luan, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

Surface mount technology (SMT) ferrite beads are often used in high-speed digital circuit designs to mitigate noise. The common modeling approach is to include SMT ferrite beads as equivalent lumped LCR circuits. The work presented in this paper included SMT ferrite beads as a frequency-dependent impedance in a PEEC-like modeling tool denoted CEMPIE, a circuit extraction approach based on a mixed-potential integral equation formulation. Agreement with measurements demonstrates the approach. The applications shown are segmentation of power areas for noise isolation, and I/O line filtering.


Mitigating Power Bus Noise With Embedded Capacitance In Pcb Designs, Minjia Xu, Todd H. Hubing, Juan Chen, James L. Drewniak, Thomas Van Doren, Richard E. Dubroff Aug 2001

Mitigating Power Bus Noise With Embedded Capacitance In Pcb Designs, Minjia Xu, Todd H. Hubing, Juan Chen, James L. Drewniak, Thomas Van Doren, Richard E. Dubroff

Electrical and Computer Engineering Faculty Research & Creative Works

This paper investigates the power bus noise and power bus impedance of printed circuit boards with four different kinds of embedded capacitance. These boards have power-ground plane pairs separated by a very thin layer of material with high dielectric permittivity. It is shown that embedded capacitance effectively reduces power bus noise over the entire frequency range evaluated (up to 5 GHz).


Green Electrochemistry. Examples And Challenges, Michael A. Matthews Aug 2001

Green Electrochemistry. Examples And Challenges, Michael A. Matthews

Faculty Publications

Electrochemical methods have been proposed for synthesis of organic compounds, including conversion of CO2. Such methods may provide a basis for environmentally friendly and sustainable methods for chemical production. Nevertheless, electrochemical syntheses are not widely utilized. Several examples of ongoing research are presented that illustrate both the opportunities as well as the challenges associated with the utilization of electrochemistry for green chemical manufacturing.


Shock Layer Instability Near The Newtonian Limit Of Hypervelocity Flows, H. G. Hornung, P. Lemieux Aug 2001

Shock Layer Instability Near The Newtonian Limit Of Hypervelocity Flows, H. G. Hornung, P. Lemieux

Mechanical Engineering

The curved bow shock in hypersonic flow over a blunt body generates a shear layer with smoothly distributed vorticity. The vorticity magnitude is approximately proportional to the density ratio across the shock, which may be very large in hypervelocity flow, making the shear layer unstable. A computational study of the instability reveals that two distinct nonlinear growth mechanisms occur in such flows: First, the vortical structures formed in the layer move supersonically with respect to the flow beneath them and form shock waves that reflect from the body and reinforce the structures. Second, the structures deform the bow shock, forming …


Investigation Of Pcb Layout Parasitics In Emi Filtering Of I/O Lines, Xiaoning Ye, Geping Liu, James L. Drewniak Aug 2001

Investigation Of Pcb Layout Parasitics In Emi Filtering Of I/O Lines, Xiaoning Ye, Geping Liu, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

EMI filters are often utilized on I/O lines to reduce high-frequency noise from being conducted or coupled off the PCB and resulting in an EMI problem. However, layout parasitics are usually inevitable in practical circuit design, and the filtering performance may vary. In this study, the impact of the board layout on the filtering performance is investigated by |S21| measurements of sample PCB boards with different filter layouts. The finite-difference time-domain method is applied to model the boards, support the experimental work, and can be used to provide a means for conducting "what-if" engineering studies.


Population Trends For Indiana Counties, Cities, And Towns 1970 – 2000, Indiana Ltap Aug 2001

Population Trends For Indiana Counties, Cities, And Towns 1970 – 2000, Indiana Ltap

Indiana Local Technical Assistance Program (LTAP) Publications

This report contains population figures and trends for the State of Indiana complied using data from the 2000 US Census. Business, industry, and local governments should find this information helpful with their planning.


Bs News Aug 2001

Bs News

Building Services Engineering

No abstract provided.


Passivity-Based Control Of Saturated Induction Motors, Levent U. Gökdere, Marwan A. Simaan, Charles W. Brice Aug 2001

Passivity-Based Control Of Saturated Induction Motors, Levent U. Gökdere, Marwan A. Simaan, Charles W. Brice

Faculty Publications

A passivity-based controller, which takes into account saturation of the magnetic material in the main flux path of the induction motor, is developed to provide close tracking of time-varying speed and flux trajectories in the high magnetic saturation regions. The proposed passivity based controller is experimentally verified. Also, a comparison between the controllers based on the saturated and nonsaturated magnetics is presented to demonstrate the benefit of the controller based on the saturated magnetics


Hydrogen-Induced Embrittlement Of Candidate Target Materials For Applications In Spallation-Neutron-Target Systems, Brendan O'Toole, Ajit K. Roy Aug 2001

Hydrogen-Induced Embrittlement Of Candidate Target Materials For Applications In Spallation-Neutron-Target Systems, Brendan O'Toole, Ajit K. Roy

Transmutation Sciences Materials (TRP)

The purpose of this project is to evaluate the effect of hydrogen on cracking of candidate target materials for applications in spallation-neutron-target (SNT) systems such as accelerator production of tritium (APT) and accelerator transmutation of waste (ATW). The test materials will undergo appropriate thermal treatments prior to being hydrogen-charged by potentiostatic cathodic polarization technique in a simulated aqueous environment at different temperatures of interest. The specimens, upon completion of testing, will be metallographically examined. Further, the scanning electron microscopy (SEM) will be used to determine the extent and nature of cracking in the specimens tested. The thrust of the proposed …


Design Of A Control System For Fmc Jetway Systems' Teleradial Bridge, Briclyn Jon Rogers Aug 2001

Design Of A Control System For Fmc Jetway Systems' Teleradial Bridge, Briclyn Jon Rogers

Undergraduate Honors Capstone Projects

FMC Jetway Systems has been manufacturing and servicing airport products for over forty years. These products include passenger boarding bridges, pre-conditioned air units, potable water systems and solid-state 400 hertz converters. Components produced by Jetway can be found on over 190 airports across the world. Their Apron Drive Passenger Boarding Bridge (Fig. 1) is the most versatile and widely used boarding bridge in the world. Only recently has the company aimed at gaining a portion of the quickly expanding market of commuter flights.


Real-Time Travel Time Estimation Using Macroscopic Traffic Flow Models, Pushkin Kachroo, Kaan Ozbay, Antoine G. Hobeika Aug 2001

Real-Time Travel Time Estimation Using Macroscopic Traffic Flow Models, Pushkin Kachroo, Kaan Ozbay, Antoine G. Hobeika

Electrical & Computer Engineering Faculty Research

This paper presents the estimation of travel time on highways based on macroscopic modelling. The focus is on real-time values as compared to average or static values. The macroscopic models are used for distributed and time/space lumped settings and corresponding travel time estimation functions and algorithms are developed. The implications of these algorithms for the implementation of various incident management and traffic control strategies are also discussed.


Critical Factors For Successful Implementation Of Enterprise Systems, Fiona Fui-Hoon Nah, J. Lau, J. Kuang Aug 2001

Critical Factors For Successful Implementation Of Enterprise Systems, Fiona Fui-Hoon Nah, J. Lau, J. Kuang

Research Collection School Of Computing and Information Systems

Enterprise resource planning (ERP) systems have emerged as the core of successful information management and the enterprise backbone of organizations. The difficulties of ERP implementations have been widely cited in the literature but research on the critical factors for initial and ongoing ERP implementation success is rare and fragmented. Through a comprehensive review of the literature, 11 factors were found to be critical to ERP implementation success – ERP teamwork and composition; change management program and culture; top management support; business plan and vision; business process reengineering with minimum customization; project management; monitoring and evaluation of performance; effective communication; software …


Fast Heuristic Minimization Of Exclusive-Sums-Of-Products, Alan Mishchenko, Marek Perkowski Aug 2001

Fast Heuristic Minimization Of Exclusive-Sums-Of-Products, Alan Mishchenko, Marek Perkowski

Electrical and Computer Engineering Faculty Publications and Presentations

Exclusive-Sums-Of-Products (ESOPs) play an important role in logic synthesis and design-for-test. This paper presents an improved version of the heuristic ESOP minimization procedure proposed in [1,2]. The improvements concern three aspects of the procedure: (1) computation of the starting ESOP cover; (2) increase of the search space for solutions by applying a larger set of cube transformations; (3) development of specialized datastructures for robust manipulation of ESOP covers. Comparison of the new heuristic ESOP minimizer EXORCISM-4 with other minimizers (EXMIN2 [3], MINT [4], EXORCISM-2 [1] and EXORCISM3 [2]) show that, in most cases, EXORCISM-4 produces results of comparable or better …


Video Partitioning By Temporal Slice Coherency, Chong-Wah Ngo, Ting-Chuen Pong, Roland T. Chin Aug 2001

Video Partitioning By Temporal Slice Coherency, Chong-Wah Ngo, Ting-Chuen Pong, Roland T. Chin

Research Collection School Of Computing and Information Systems

We present a novel approach for video partitioning by detecting three essential types of camera breaks, namely cuts, wipes, and dissolves. The approach is based on the analysis of temporal slices which are extracted from the video by slicing through the sequence of video frames and collecting temporal signatures. Each of these slices contains both spatial and temporal information from which coherent regions are indicative of uninterrupted video partitions separated by camera breaks. Properties could further be extracted from the slice for both the detection and classification of camera breaks. For example, cut and wipes are detected by color-texture properties, …


A Multi-Agent Framework For Supporting Intelligent Fourth-Party Logistics, Hoong Chuin Lau, G. Lo Aug 2001

A Multi-Agent Framework For Supporting Intelligent Fourth-Party Logistics, Hoong Chuin Lau, G. Lo

Research Collection School Of Computing and Information Systems

A distributed intelligent agent-based framework that supports fourth-party logistics optimization under a web-based e-Commerce environment has been proposed in this paper. In the framework, customer job requests come through an e-Procurement service. These requests are consolidated and pushed to the e-Market Place service periodically. The e-Market Place then serves as a broker that allows intelligent agents to bid to serve these requests optimally in real-time by solving multiple instances of underlying logistics optimization problem. The resulting system was implemented based on the Java 2 Enterprise Edition (J2EE) platform using distributed system technology for communication between objects.


Analysis Of A New Vehicle Scheduling And Location Problem, Ebru K. Bish, Thin Yin Leong, Chun-Lun Li, Jonathan W. C. Ng, David Simchi-Levi Aug 2001

Analysis Of A New Vehicle Scheduling And Location Problem, Ebru K. Bish, Thin Yin Leong, Chun-Lun Li, Jonathan W. C. Ng, David Simchi-Levi

Research Collection School Of Computing and Information Systems

We consider a container terminal discharging containers from a ship and locating them in the terminal yard. Each container has a number of potential locations in the yard where it can be stored. Containers are moved from the ship to the yard using a fleet of vehicles, each of which can carry one container at a time. The problem is to assign each container to a yard location and dispatch vehicles to the containers so as to minimize the time it takes to download all the containers from the ship. We show that the problem is NP-hard and develop a …


Simulation Of Engineering Systems Described By High-Index Dae And Discontinuous Ode Using Single Step Methods, Marc Compere Aug 2001

Simulation Of Engineering Systems Described By High-Index Dae And Discontinuous Ode Using Single Step Methods, Marc Compere

Publications

This dissertation presents numerical methods for solving two classes of or-dinary diferential equations (ODE) based on single-step integration meth-ods. The first class of equations addressed describes the mechanical dynamics of constrained multibody systems. These equations are ordinary differential equations (ODE) subject to algebraic constraints. Accordinly they are called differential-algebraic equations (DAE).

Specific contributions made in this area include an explicit transforma-tion between the Hessenberg index-3 form for constrained mechanical systems to a canonical state-space form used in the nonlinear control communities. A hybrid solution method was developed that incorporates both sliding-mode control (SMC) from the controls literature and post-stabilization from …


Multidirectional Compliance And Constraint For Improved Robotic Deburring. Part 2: Improved Bracing, Joseph M. Schimmels Aug 2001

Multidirectional Compliance And Constraint For Improved Robotic Deburring. Part 2: Improved Bracing, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

This two-part paper presents a method for both improving the positioning capability and increasing the effective stiffness (bracing) of a robotic manipulator through multidirectional compliance and constraint. Improved positioning and improved bracing are attained through the effective use of multiple unilateral kinematic constraints in different directions. The companion paper identified how to specify the compliant characteristics of a manipulator so contact forces lead to deflections that eliminate positional misalignments and result in improved relative positioning through force guidance. In this part, we show that the characteristics beneficial to force guidance are the same characteristics that provide improved bracing when partially …


Spline Based Path Planning For Unmanned Air Vehicles, Kevin B. Judd, Timothy W. Mclain Aug 2001

Spline Based Path Planning For Unmanned Air Vehicles, Kevin B. Judd, Timothy W. Mclain

Faculty Publications

A trajectory planning scheme that generates feasible flight routes for an unmanned air vehicle (UAV) is developed. A preliminary path is generated from a Voronoi diagram based on threat locations. This path consists of a series of straight-line segments that cannot be followed exactly by the UAV. Using a series of cubic splines to connect these straight-line segments, this path is refined into an optimum path that is flyable by the UAV. Utilizing a decomposition strategy, both the full path (coarse detail) to the target and the proximate optimum path (fine detail) near the UAV can be quickly computed. The …


Learning To Move Amid Uncertainty, Robert A. Scheidt, Jonathan B. Dingwell, Ferdinando A. Mussa-Ivaldi Aug 2001

Learning To Move Amid Uncertainty, Robert A. Scheidt, Jonathan B. Dingwell, Ferdinando A. Mussa-Ivaldi

Biomedical Engineering Faculty Research and Publications

We studied how subjects learned to make movements against unpredictable perturbations. Twelve healthy human subjects made goal-directed reaching movements in the horizontal plane while holding the handle of a two-joint robotic manipulator. The robot generated viscous force fields that perturbed the limb perpendicular to the desired direction of movement. The amplitude (but not the direction) of the viscous field varied randomly from trial to trial. Systems identification techniques were employed to characterize how subjects adapted to these random perturbations. Subject performance was quantified primarily using the peak deviation from a straight-line hand path. Subjects adapted their arm movements to the …


Human Factors Survey Of Aviation Technical Manuals, Phase 1: Manual Development Procedures, Alex Chaparro, Loren S. Groff Aug 2001

Human Factors Survey Of Aviation Technical Manuals, Phase 1: Manual Development Procedures, Alex Chaparro, Loren S. Groff

Publications

This report contains the results from Phase 1 of a three-phase research effort. Phase 1 examines aviation industry procedures for developing maintenance technical data. Phase 2 will document user problems with maintenance technical data. Phase 3 will identify maintenance technical data development improvements by applying human factors principles. Five aircraft manufacturers were surveyed regarding company policy, communication, data tracking, user feedback, and error reduction efforts. The five industry participants represent both regional and large commercial transport manufacturers. Phase 1 survey results revealed three significant maintenance technical data issues: inconsistent development process guidelines, reactive rather than proactive response to user feedback, …


University Of Nevada, Las Vegas Advanced Accelerator Applications University Participation Program: Quarterly Report First Quarter (March-May 2001), Anthony Hechanova Jul 2001

University Of Nevada, Las Vegas Advanced Accelerator Applications University Participation Program: Quarterly Report First Quarter (March-May 2001), Anthony Hechanova

Transmutation Research Program Reports (TRP)

This Quarterly Report is a primary deliverable from the University of Nevada, Las Vegas (UNLV) Advanced Accelerator Applications (AAA) University Participation Program (UPP) director to the U.S. Department of Energy Office of Nuclear Energy, Science and Technology (DOE-NE) as defined in the UNLV AAA Proposal.

The foundation of the UNLV AAA University Participation Program started as a grassroots effort in the late 1990s among community members and local, state, and federal representatives to encourage research and development of technical alternatives to direct disposal of used nuclear fuel which had been targeted since the early 1980s for Yucca Mountain, Nevada. A …


Electromagnetics, David V. Arnold, Richard H. Selfridge, Karl F. Warnick Jul 2001

Electromagnetics, David V. Arnold, Richard H. Selfridge, Karl F. Warnick

Faculty Publications

Many applications of electrical engineering require a knowledge of the behavior of voltages and currents in electronic devices and within conductors. In many other situations it is not enough to understand the behavior the voltages and currents in just the conductors and other components, but also the influence of the voltage and current on surrounding materials.