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Articles 175831 - 175860 of 197997

Full-Text Articles in Engineering

A New Neural Architecture For Homing Missile Guidance, S. N. Balakrishnan, Victor Biega Jan 1995

A New Neural Architecture For Homing Missile Guidance, S. N. Balakrishnan, Victor Biega

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We present a new neural architecture which imbeds dynamic programming solutions to solve optimal target-intercept problems. They provide feedback guidance solutions, which are optimal with any initial conditions and time-to-go, for a 2D scenario. The method discussed in this study determines an optimal control law for a system by successively adapting two networks - an action and a critic network. This method determines the control law for an entire range of initial conditions; it simultaneously determines and adapts the neural networks to the optimal control policy for both linear and nonlinear systems. In addition, it is important to know that …

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High Temperature Interfacial Phenomena In Processing Cofired Ceramics For Electronic Packaging Of Semiconductor Devices, P. D. Ownby, D. A. Weirauch Jr., J. E. Lazaroff Jan 1995

High Temperature Interfacial Phenomena In Processing Cofired Ceramics For Electronic Packaging Of Semiconductor Devices, P. D. Ownby, D. A. Weirauch Jr., J. E. Lazaroff

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

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Anomalous-Diffusion Model Of Ionic Transport In Oxide Glasses, David L. Sidebottom, Peter F. Green, Richard K. Brow Jan 1995

Anomalous-Diffusion Model Of Ionic Transport In Oxide Glasses, David L. Sidebottom, Peter F. Green, Richard K. Brow

Materials Science and Engineering Faculty Research & Creative Works

The power-law frequency dependence of both the conductivity, (), and permittivity, (), of ion-conducting materials suggests that self-similar or scale-invariant behavior influences the transport of ions at high frequencies. Using an anomalous-diffusion model, we derive relevant power-law expressions for () and () and compare these with measurements performed on LiPO3 glass. Superior fits to the measured data are obtained compared to the commonly used Kohlrausch-Williams-Watts (KWW) description of the electrical modulus, most particularly in the notorious high-frequency regime. Evaluation of our results in terms of an anomalous-diffusion model suggests the dominance of interaction-based constraints to diffusion. © 1995 The American …

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Two Contributions To The Ac Conductivity Of Alkali Oxide Glasses, David L. Sidebottom, Peter F. Green, Richard K. Brow Jan 1995

Two Contributions To The Ac Conductivity Of Alkali Oxide Glasses, David L. Sidebottom, Peter F. Green, Richard K. Brow

Materials Science and Engineering Faculty Research & Creative Works

Although the frequency dependent conductivity of ion-containing glasses often displays scale invariant power law dispersion at high temperatures, the exponent increases to unity at lower temperatures. We report measurements of the conductivity of a series of alkali metaphosphate glasses including a mixed alkali composition and demonstrate that this temperature dependence results from the superposition of two power law dispersions originating from separate mechanism, and does not indicate any intrinsic change in scaling of the process which dominates at high temperatures. © 1995 The American Physical Society.

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Method Of Forming A Plasma Sprayed Interconnection Layer On An Electrode Of An Electrochemical Cell, Charles J. Spengler, George R. Folser, Shailesh D. Vora, Lewis Kuo, Von Richards Jan 1995

Method Of Forming A Plasma Sprayed Interconnection Layer On An Electrode Of An Electrochemical Cell, Charles J. Spengler, George R. Folser, Shailesh D. Vora, Lewis Kuo, Von Richards

Materials Science and Engineering Faculty Research & Creative Works

A dense, substantially gas-tight, electrically conductive interconnection layer is formed on an air electrode structure of an electrochemical cell by (A) providing an electrode surface; (B) forming on a selected portion of the electrode surface, a layer of doped LaCrO.sub.3 particles doped with an element selected from Ca, Sr, Ba, Mg, Co, Ni, Al and mixtures thereof by plasma spraying doped LaCrO.sub.3 powder, preferably compensated with chromium as Cr.sub.2 O.sub.3 and/or dopant element, preferably by plasma arc spraying; and, (C) heating the doped and compensated LaCrO.sub.3 layer to about 1100 to provide a dense, substantially gas-tight, substantially hydration-free, electrically conductive …

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A Positron Annihilation Study Of Rotating Beam Fatigue Damage In The Superalloy Haynes 188, D. Hoeckelman, Hollis P. Leighly Jan 1995

A Positron Annihilation Study Of Rotating Beam Fatigue Damage In The Superalloy Haynes 188, D. Hoeckelman, Hollis P. Leighly

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

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Electrical Characterization Of The (La,Ca) (Cr,Co)O3 System, S. R. Sehlin, Harlan U. Anderson, Don M. Sparlin Jan 1995

Electrical Characterization Of The (La,Ca) (Cr,Co)O3 System, S. R. Sehlin, Harlan U. Anderson, Don M. Sparlin

Materials Science and Engineering Faculty Research & Creative Works

The results of electrical conductivity and thermopower measurements are presented for selected (La,Ca)(Cr,Co)O3 compositions. The La1 - xCaxCrO3 compounds are typical p-type small polaron conductors. The La1 - xCaxCrO3 compounds are found to be small polaron conductors at room temperature for x ≤ 0.20 with a higher electrical conductivity than the corresponding chromite's. The electrical conductivity at room temperature is lower for Co-rich compositions than for Cr-rich compositions for compositions containing 10 mol% and 20 mol% Ca. This fact is attributed to the trapping of p-type small polarons at energetically lower Cr sites, resulting in a broad room temperature conductivity …

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Cossap Simulation Model Of Ds-Cdma Indoor Microwave Atm Lan, Keng T. Tan Jan 1995

Cossap Simulation Model Of Ds-Cdma Indoor Microwave Atm Lan, Keng T. Tan

Theses : Honours

This thesis presents an original work in the area of designing and implementing a simulation testbed for modelling a high speed spread spectrum Asynchronous Transfer Mode (ATM) Local Area Network (LAN). The spread spectrum technique used in this LAN model is Direct Sequence Code Division Multiple Access (DS-CDMA). The simulation model includes at least a physical layer of such a LAN, embedded into the COSSAP1 simulation environment, and has been fully tested. All the newly developed building blocks are comprised of standard blocks from the COSSAP libraries or compatible user-built primitive blocks (only where it is absolutely necessary), and …

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Efficient Axis And Circle Detection Through Hough Transformation, Karissa E. Hobert Jan 1995

Efficient Axis And Circle Detection Through Hough Transformation, Karissa E. Hobert

Presidential Scholars Theses (1990 – 2006)

Computer vision and human vision are quite different. While a person can look at an object and easily recognize it, a computer is does not understand the the objects it is seeing. Finding axes and circles in an image is an intermediate step in designing a machine with the ability to recognize shapes and objects. Through the utilization of contour and smoothed local symmetry information, the main axes of an image are determined and may be used to facilitate shape and object analysis. A Hough transform algorithm detects the most popular lines from a set of candidate axis points. This …

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Evolution Of Emergent Computation, James P. Crutchfield, Melanie Mitchell Jan 1995

Evolution Of Emergent Computation, James P. Crutchfield, Melanie Mitchell

Computer Science Faculty Publications and Presentations

A simple evolutionary process can discover sophisticated methods for emergent information processing in decentralized spatially-extended systems. The mechanisms underlying the resulting emergent computation are explicated by a novel technique for analyzing particle-based logic embedded in pattern-forming systems. Understanding how globally-coordinated computation can emerge in evolution is relevant both for the scientific understanding of natural information processing and for engineering new forms of parallel computing systems.

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Improved Strategies For Deploying Vehicle-Actuated Control At Isolated Signalized Intersections, Michael J. Cassidy, Yu-Hao Chuang, Jeffrey Dunn Vitale Jan 1995

Improved Strategies For Deploying Vehicle-Actuated Control At Isolated Signalized Intersections, Michael J. Cassidy, Yu-Hao Chuang, Jeffrey Dunn Vitale

JTRP Technical Reports

This research has sought to demonstrate potential benefits from deploying enhanced vehicle actuation strategies at isolated signalized intersections. The work has exploited microscopic, stochastic simulation to evaluate impacts of enhanced vehicle-actuated (VA) control schemes for an array of operating conditions. Simulated outcomes (i.e. average vehicle delays) generated under the enhanced strategies were compared with outcomes resulting from more “conventional VA control policies. Findings from this work suggest that substantial delay reduction generally occurs by exploiting VA strategies which seek to 1) facilitate the use of the clearance interval by discharging vehicles, 2) shorten the duration of the required clearance interval …

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Development Of Annual Permit Procedure For Overweight Trucks On Indiana Highways, Robert K. Whitford, David P. Moffett Jan 1995

Development Of Annual Permit Procedure For Overweight Trucks On Indiana Highways, Robert K. Whitford, David P. Moffett

JTRP Technical Reports

Overweight truck permitting in Indiana is presently done on a per trip basis. This study evaluated alternatives to each trip having to make a call to the INDOT permit office to gain a permit. The study was originally requested by the Indiana State Legislature under P.L. 122-1993 section 7 in response to delays in getting permits. The report’s six chapters are 1. Introduction and Summary 2. Review of Other States’ Permitting Systems 3. Framework for Policy Evaluation 4. Permits for Michigan Truck-Trains 5. Overweight and Overweight/Oversized Trucks 6. Implementation Suggestions – PLUS -- 7. Appendices. A Michigan Truck-Train is a …

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Effects Of Salt And Trace Minerals For Bituminous Pavement Literature Review, Information Gathering, And Research Plan Development, Robert Allan Pittenger, Terry R. West Jan 1995

Effects Of Salt And Trace Minerals For Bituminous Pavement Literature Review, Information Gathering, And Research Plan Development, Robert Allan Pittenger, Terry R. West

JTRP Technical Reports

A review of current literature on the effects of deicing salt and trace minerals, such as sulfate, on aggregate deterioration was conducted. Such deterioration in both Portland cement concrete, and bituminous pavements was reviewed. For Portland cement concrete, it was determined that current research on the effects of moisture and deicing salt on aggregates concrete matrix durability, with little discussion on the effects on aggregates. The effects of trace minerals in deicing salt are also rarely discussed. Pore size distribution, insoluble residue, absorption, and susceptibility to alkali-silica reaction all appear to affect aggregate durability in the presence of moisture of …

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Fatigue Strength Of Girders With Tapered Covered Plates, Ahmed Farouk Hassan, Mark D. Bowman Jan 1995

Fatigue Strength Of Girders With Tapered Covered Plates, Ahmed Farouk Hassan, Mark D. Bowman

JTRP Technical Reports

This report represents results from a study to determine the fatigue strength of steel beams with welded partial-length cover plates. Results of an experimental investigation that examined the fatigue strength of various cracked cover plate end details that were subsequently repaired are presented. The repair methods investigated included a slip-critical bolted splice plate connection, air-hammer peening, and a combination of the previous two called a partial bolted splice connection. Also, an analytical model was developed to predict the fatigue behavior of a cover plate and detail that is repaired using one of the three repair methods investigated and which contains …

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New Treatment Combinations For Control Of Brush And Vegetation Management Along Indiana Roadsides, D. James Morré Jan 1995

New Treatment Combinations For Control Of Brush And Vegetation Management Along Indiana Roadsides, D. James Morré

JTRP Technical Reports

This report represents results from a project for research to develop and implement new treatment mixtures for control of problem brush, trees and other woody species and herbicide-resistant weeds along Indiana roadsides. An environmentally safe mixture of trichlopyr (Galon Herbicide) and ammonium nitrate for one application control of deciduous roadside vegetation was developed. Also discovered and developed was a new, environmentally safe and effective TR series of additives that enhance the action of the auxin herbicides (trichlopyr, 2,4-D, picloram) for inclusion in both the brush control mixtures and control of milkweed, Canada thistle, bindweed, ground cherry and other perennial, herbicide-resistant …

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Predicting Traffic Impacts At Two-Lane Highway Work Zones, Michael J. Cassidy, Youngtae Son Jan 1995

Predicting Traffic Impacts At Two-Lane Highway Work Zones, Michael J. Cassidy, Youngtae Son

JTRP Technical Reports

Maintenance or reconstruction activity on a two-lane highway often requires a lane closure. The implementation of “one-way traffic control,” required to maintain traffic flow throughout the work zone, typically produces significant motorist delay. This report describes the adaptation and application of queuing models, originally derived for intersections controlled by vehicle-actuated traffic signals, to estimate delay at two-lane highway work zones. The models estimate expected delay as a function of directional traffic demand rates, work zone physical length and observed traffic measures. Validation efforts using simulation suggest that the models accurately predict the impacts of two-lane highway lane closures.

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Stay-In Place Deck Panels - Part 1, Ariel Goldman, Menashi D. Cohen, J. A. Ramirez Jan 1995

Stay-In Place Deck Panels - Part 1, Ariel Goldman, Menashi D. Cohen, J. A. Ramirez

JTRP Technical Reports

The objective of this study was the evaluation of frost resistance of concrete bridge decks with stay-in-place galvanized steel deck forms. The evaluation included specific aspects related to the potential for D-cracking in concrete bridge decks with these forms. The experimental program has been set up so that the real parameters of the bridge deck overlays and the environmental conditions could have been modeled. The program included freezing-and-thawing testing of large concrete slab specimens (22 ¼” x 17 ¼” x 5 ¼”) situated in a computer-controlled environmental chamber and of small specimens (3” x 4” x 12”) immersed in water …

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Time-Frequency Shift-Tolerance And Counterpropagation Network With Applications To Phoneme Recognition, Li-Minn Ang Jan 1995

Time-Frequency Shift-Tolerance And Counterpropagation Network With Applications To Phoneme Recognition, Li-Minn Ang

Theses : Honours

Human speech signals are inherently multi-component non-stationary signals. Recognition schemes for classification of non-stationary signals generally require some kind of temporal alignment to be performed. Examples of techniques used for temporal alignment include hidden Markov models and dynamic time warping. Attempts to incorporate temporal alignment into artificial neural networks have resulted in the construction of time-delay neural networks. The nonstationary nature of speech requires a signal representation that is dependent on time. Time-frequency signal analysis is an extension of conventional time-domain and frequency-domain analysis methods. Researchers have reported on the effectiveness of time-frequency representations to reveal the time-varying nature of …

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Video Coding For Bit Rates 64kbps And Below, Geoffrey N. Alagoda Jan 1995

Video Coding For Bit Rates 64kbps And Below, Geoffrey N. Alagoda

Theses : Honours

With digital motion video for either transmission or storage, there always exists a trade-off between the data transmission rate and the picture quality. The lower the transmission bit-rate is made, the more the quality of the image tends to degrade. With usual transform coding schemes the degradation usually occurs when low bit-rates, that is less than about 64Kbps, are used. The resultant image tends to suffer visually from a ''blocking" effect. This thesis therefore, is based on the development of a different implementation scheme, for motion video compression or encoding, so as to support both low bit-rates, around 64Kbps or …

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Robust Decentralised Variable Structure Control For Rigid Robotic Manipulators, Thasapalan Kuhan Jan 1995

Robust Decentralised Variable Structure Control For Rigid Robotic Manipulators, Thasapalan Kuhan

Theses : Honours

In this thesis, the problem of robust variable structure control for non-linear rigid robotic manipulators is investigated. Robustness and convergence results are presented for variable structure control systems of robotic manipulators with bounded unknown disturbances, nonlinearities, dynamical couplings and parameter uncertainties. The major outcomes of the work described in this thesis are summarised as given below. The basic variable structure theory is surveyed, and some basic ideas such as sliding mode designs, robustness analysis and control1er design methods for linear or non-linear systems are reviewed. Three recent variable structure control schemes for robotic manipulators are discussed and compared to highlight …

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Electrochemical Determination Of The Diffusion Coefficient Of Hydrogen Through An Lani4.25Al0.75 Electrode In Alkaline Aqueous Solution, G. Zheng, Branko N. Popov, Ralph E. White Jan 1995

Electrochemical Determination Of The Diffusion Coefficient Of Hydrogen Through An Lani4.25Al0.75 Electrode In Alkaline Aqueous Solution, G. Zheng, Branko N. Popov, Ralph E. White

Faculty Publications

The constant potential and constant current discharge techniques were used to determine the hydrogen diffusion coefficients in an LaNi4.25Al0.75 electrode. The values obtained were 2.97 × 10–11 and 3.30 × 10–11 cm2/s, respectively. The advantages and disadvantages of these two techniques are discussed.

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A Parallel-Plate Electrochemical Reactor Model For The Destruction Of Nitrate And Nitrite In Alkaline Waste Solutions, D. H. Coleman, Ralph E. White, D. T. Hobbs Jan 1995

A Parallel-Plate Electrochemical Reactor Model For The Destruction Of Nitrate And Nitrite In Alkaline Waste Solutions, D. H. Coleman, Ralph E. White, D. T. Hobbs

Faculty Publications

A parallel-plate electrochemical reactor model with multiple reactions at both electrodes and anolyte and catholyte recirculation tanks was modeled for the electrochemical destruction of nitrate and nitrite species in an alkaline solution. The model can be used to predict electrochemical reaction current efficiencies and outlet concentrations of species from the reactor, given inlet feed conditions and cell operating conditions. Also, predictions are made for off-gas composition and liquid-phase composition in the recirculation tanks. The results of case studies at different applied potentials are shown here. At lower applied potentials, the model predictions show that the destruction process is more energy …

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Mathematical Modeling Of A Nickel-Cadmium Cell: Proton Diffusion In The Nickel Electrode, Pauline De Vidts, Ralph E. White Jan 1995

Mathematical Modeling Of A Nickel-Cadmium Cell: Proton Diffusion In The Nickel Electrode, Pauline De Vidts, Ralph E. White

Faculty Publications

In this paper we present a mathematical model of a sealed nickel-cadmium cell that includes proton diffusion and ohmic drop through the active material in the nickel electrode. The model is used to calculate sensitivity coefficients for various parameters in the model. These calculations show that the discharge voltage of the cell is affected mostly by the kinetics of the nickel reaction. Toward the end of discharge, proton diffusion also becomes important, because the proton diffusion process affects the active material utilization significantly. During charge, the cell voltage is mainly affected by the kinetics of the nickel reaction until the …

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Mathematical Modeling For The Discharge Of A Metal Hydride Electrode, Pauline De Vidts, Javier Delgado, Ralph E. White Jan 1995

Mathematical Modeling For The Discharge Of A Metal Hydride Electrode, Pauline De Vidts, Javier Delgado, Ralph E. White

Faculty Publications

No abstract provided.

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Hydrogen-Atom Direct-Entry Mechanism Into Metal Membranes, G. Zheng, Branko N. Popov, Ralph E. White Jan 1995

Hydrogen-Atom Direct-Entry Mechanism Into Metal Membranes, G. Zheng, Branko N. Popov, Ralph E. White

Faculty Publications

The hydrogen-atom direct-entry mechanism is used to explain why the steady-state hydrogen permeation current density through a metal membrane is directly proportional to the cathodic current density, ic, and is independent of the membrane thickness when ic is small.

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A Boundary-Layer Model Of A Parallel-Plate Electrochemical Reactor For The Destruction Of Nitrates And Nitrites In Alkaline Waste Solutions, Shailesh Prasad, John W. Weidner, Andrew E. Farell Jan 1995

A Boundary-Layer Model Of A Parallel-Plate Electrochemical Reactor For The Destruction Of Nitrates And Nitrites In Alkaline Waste Solutions, Shailesh Prasad, John W. Weidner, Andrew E. Farell

Faculty Publications

Electrochemical processes appear to be attractive for treating low level nuclear wastes. The development of a simple divided electrochemical-cell model operating in a batch mode, used for the reduction of nitrates and nitrites from nuclear wastes, is presented. This model, based on a boundary-layer approach, is simple and yet encompasses the key features of a previously developed distributed-parameter model that includes diffusion, migration, and convection as the flux components. Because it dramatically reduces computation time, this boundary-layer model is well suited for use in a complex interactive flowsheet model and for optimization studies. The boundary-layer model is used to predict …

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Electrowinning Of Non-Noble Metals With Simultaneous Hydrogen Evolution At Flow-Through Porous Electrodes Ii. Experimental, Mahmoud M. Saleh, John W. Weidner, Bahgat E. Ei-Anadouli, Badr G. Ateya Jan 1995

Electrowinning Of Non-Noble Metals With Simultaneous Hydrogen Evolution At Flow-Through Porous Electrodes Ii. Experimental, Mahmoud M. Saleh, John W. Weidner, Bahgat E. Ei-Anadouli, Badr G. Ateya

Faculty Publications

This paper presents an interpretation of the experimental results obtained on the electrowinning of zinc at a flow-through porous electrode in light of a mathematical model which was presented in Part I. The process is accompanied by simultaneous hydrogen evolution within the electrode, which increases the pore electrolyte resistivity and decreases the coulombic efficiency. We measured polarization curves, coulombic efficiencies, and current distributions under various conditions of zincate concentrations, flow rates, cell current, and electrode thickness. Reasonable agreement between the measured and predicted current distributions was obtained only under conditions of high electrolyte flow rates, low cell currents, and thinner …

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A Cultural Anthropological Overview Of The Niobara/Missouri National Scenic Riverways, Beth R. Ritter, Robert K. Hitchcock, Michelle L. Watson, Michele Voeltz, Thomas D. Thiessen, Oliver Froehling, Rebecca Hautzinger, Judith Campbell Miller, Michele Moray, Leonard R. Bruguier, Gloria Rial Jan 1995

A Cultural Anthropological Overview Of The Niobara/Missouri National Scenic Riverways, Beth R. Ritter, Robert K. Hitchcock, Michelle L. Watson, Michele Voeltz, Thomas D. Thiessen, Oliver Froehling, Rebecca Hautzinger, Judith Campbell Miller, Michele Moray, Leonard R. Bruguier, Gloria Rial

United States Army Corps of Engineers, Omaha District

This document is a cultural anthropological overview and assessment of the Niobrara/Missouri National Scenic Riverways (NIMI). It represents the first formal planning step taken by the National Park service (NPS) to identify the different ethnic and religious groups of people that have historical and/or contemporary ties to the NIMI region. It primarily focuses on American Indian groups that used the NIMI region for various purposes in past historical times. The discussion of American Indian peoples emphasizes the three Federally-recognized tribes that reside in the NIMI region today, the Poncas, Santee Sioux, and Yankton sioux. Other groups that used the NIMI …

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An Organizational Learning Approach To Domain Analysis, Scott Henninger, Kris Lappala, Anand Raghavendran Jan 1995

An Organizational Learning Approach To Domain Analysis, Scott Henninger, Kris Lappala, Anand Raghavendran

School of Computing: Conference and Workshop Papers

As the application of computer technology continues to proliferate and diversify, the identification and understanding of application domains is becoming increasingly important to software development methodologies. Domain analysis techniques have been developed to accumulate and formalize the knowledge necessary for successful software reuse. These techniques have been shown to be useful, but suffer from defining the domain too restrictively, burying important relationships deep in domain taxonomies, and prohibiting flexible identification of domains with common issues. Techniques are needed that dynamically detect recurring patterns of activities in development projects. This paper presents a method for developing and refining the knowledge and …

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Issues In Developing An Undergraduate Simulation Course, Paul Savory Jan 1995

Issues In Developing An Undergraduate Simulation Course, Paul Savory

Department of Industrial and Management Systems Engineering: Faculty Publications

Experience in developing an undergraduate simulation course is described. The course introduces the philosophies, principles, and methodologies for discrete-event simulation modeling. Strategy in choosing the course simulation software is discussed, plus important areas of teaching emphasis are highlighted.

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