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1999

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Articles 1261 - 1290 of 1307

Full-Text Articles in Engineering

Improvements In Modeling Dissolved Oxygen In Activated Sludge Systems, Jacek Makinia, Scott A. Wells Jan 1999

Improvements In Modeling Dissolved Oxygen In Activated Sludge Systems, Jacek Makinia, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

The aim of this research was to show the impact of the flow conditions and variations in the aeration intensity on changes in the predicted dissolved oxygen (DO) concentrations in a full-scale activated sludge reactor. The Activated Sludge Model No. 1 was used to describe the biochemical processes. The studies were performed at the Rock Creek wastewater treatment plant in Hillsboro, OR (USA). The simulation results were compared with data originating from two 24-hour experiments. The model that best reflected the spatial and diurnal distributions of the DO concentrations was the one-dimensional advection-dispersion equation with a variable overall oxygen mass …


Environmental Performance Analysis Of Solid Freedom Fabrication Processes, Yanchun Luo, Zhiming Ji, Ming-Chuan Leu, R. J. Caudill Jan 1999

Environmental Performance Analysis Of Solid Freedom Fabrication Processes, Yanchun Luo, Zhiming Ji, Ming-Chuan Leu, R. J. Caudill

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper presents a method for analyzing the environmental performance of solid freeform fabrication (SFF) processes. In this method, each process is divided into life phases. Environmental effects of every process phase are then analyzed and evaluated based on the environmental and resource management data. These effects are combined to obtain the environmental performance of the process. The analysis of the environmental performance of SFF processes considers the characteristics of SFF technology, includes material, energy consumption, processes wastes, and disposal. Case studies for three typical SFF processes: stereolithography (SL); selective laser sintering (SLS); and fused deposition modeling (FDM) are presented …


Multiple Stochastic Learning Automata For Vehicle Path Control In An Automated Highway System, Cem Unsal, Pushkin Kachroo, John S. Bay Jan 1999

Multiple Stochastic Learning Automata For Vehicle Path Control In An Automated Highway System, Cem Unsal, Pushkin Kachroo, John S. Bay

Electrical & Computer Engineering Faculty Research

This paper suggests an intelligent controller for an automated vehicle planning its own trajectory based on sensor and communication data. The intelligent controller is designed using the learning stochastic automata theory. Using the data received from on-board sensors, two automata (one for lateral actions, one for longitudinal actions) can learn the best possible action to avoid collisions. The system has the advantage of being able to work in unmodeled stochastic environments, unlike adaptive control methods or expert systems. Simulations for simultaneous lateral and longitudinal control of a vehicle provide encouraging results


Incident Management In Intelligent Transportation Systems, Kaan Ozbay, Pushkin Kachroo Jan 1999

Incident Management In Intelligent Transportation Systems, Kaan Ozbay, Pushkin Kachroo

Electrical & Computer Engineering Faculty Research

Since the conception of Intelligent Transportation Systems (ITS) in the 1980s, many transportation researchers have also worked on the development of incident management models and integrated systems for real-time operations. ITS created the required infrastructure for collecting, processing, and managing real-time traffic data that can be used to develop on-line incident management strategies. This book provides the reader with a broad picture of the overall incident management process in the context of ITS along with a quick review of the models and systems developed by numerous researchers worldwide. This book is a direct result of the long-term incident management research …


Potential For Aquifer Storage And Recovery In Box Elder And Cache Counties, Mariush Kemblowski, Tom Lachmar, Richard Peralta Jan 1999

Potential For Aquifer Storage And Recovery In Box Elder And Cache Counties, Mariush Kemblowski, Tom Lachmar, Richard Peralta

Civil and Environmental Engineering Faculty Publications

Groundwater artificial storage and recovery (ASR) has become a favorable means in the arid west to store water produced in excess of need during winter months for use in drier times of the year. ASR may be accomplished by injection of suitable water into the groundwater system via wells to be pumped out later, or by recovery of seepage via wells from surface water impoundments or infiltration networks. This report will present pertinent hydrogeologic information for the location of an artificial groundwater storage and recovery project in Utah's northeastern Box Elder County.


Feedback Control Theory For Dynamic Traffic Assignment, Pushkin Kachroo, Kaan Ozbay Jan 1999

Feedback Control Theory For Dynamic Traffic Assignment, Pushkin Kachroo, Kaan Ozbay

Electrical & Computer Engineering Faculty Research

Traditionally, traffic assignment and traffic control in general have mostly been performed using optimisation techniques which do not lend themselves to real-time control. This volume presents feedback control techniques for performing traffic assignment in real-time, where traffic diversion control variables are instantaneous functions of sensed traffic variables. The authors outline the whole theory behind Intelligent Transportation Systems (ITS) which allows traffic variables to be sensed in real time and microprocessors to use the sensed traffic variable input to perform the traffic actuation tasks. They show h ow to design feedback controllers to perform dynamic traffic routing and assignment, and present …


Sinmap 2.0 - A Stability Index Approach To Terrain Stability Hazard Mapping, User's Manual, Robert T. Pack, David G. Tarboton, C. N. Goodwin Jan 1999

Sinmap 2.0 - A Stability Index Approach To Terrain Stability Hazard Mapping, User's Manual, Robert T. Pack, David G. Tarboton, C. N. Goodwin

Civil and Environmental Engineering Faculty Publications

SINMAP 2.0 (Stability Index MAPping) is an ArcGIS 9.0 plug-in that implements the computation and mapping of a slope stability index based upon geographic information, primarily digital elevation data. This report describes the theoretical basis for the calculation of the stability index, describes the implementation, presents several case studies and describes use of the accompanying software. SINMAP has its theoretical basis in the infinite plane slope stability model with wetness (pore pressures) obtained from a topographically based steady state model of hydrology. Digital elevation model (DEM) methods are used to obtain the necessary input information (slope and specific catchment area). …


Potential For Aquifer Storage And Recovery In Box Elder And Cache Counties, Richard C. Peralta, Tom Lachmar, Mariush Kemblowski Jan 1999

Potential For Aquifer Storage And Recovery In Box Elder And Cache Counties, Richard C. Peralta, Tom Lachmar, Mariush Kemblowski

Civil and Environmental Engineering Faculty Publications

Groundwater artificial storage and recovery (ASR) has become a favorable means in the arid west to store water produced in excess of need during winter months for use in drier times of the year. ASR may be accomplished by injection of suitable water into the groundwater system via wells to be pumped out later, or by recovery of seepage via wells from surface water impoundments or infiltration networks. This report will present pertinent hydrogeologic information for the location of an artificial groundwater storage and recovery project in Utah's northeastern Box Elder County.


(Ω, Ξ)-Logic: On The Algebraic Extension Of Coalgebraic Specifications, Rolf Hennicker, Alexander Kurz Jan 1999

(Ω, Ξ)-Logic: On The Algebraic Extension Of Coalgebraic Specifications, Rolf Hennicker, Alexander Kurz

Engineering Faculty Articles and Research

We present an extension of standard coalgebraic specification techniques for statebased systems which allows us to integrate constants and n-ary operations in a smooth way and, moreover, leads to a simplification of the coalgebraic structure of the models of a specification. The framework of (Ω,Ξ)-logic can be considered as the result of a translation of concepts of observational logic (cf. [9]) into the coalgebraic world. As a particular outcome we obtain the notion of an (Ω, Ξ)- structure and a sound and complete proof system for (first-order) observational properties of specifications.


Mössbauer Effect Determination Of Relative Recoilless Fractions For Iron Oxides, Sei J. Oh, Desmond C. Cook Jan 1999

Mössbauer Effect Determination Of Relative Recoilless Fractions For Iron Oxides, Sei J. Oh, Desmond C. Cook

Physics Faculty Publications

The relative recoilless fraction (F-value) of each of six iron oxides, defined as the ratio of the recoil-free fractions of two different materials, was experimentally determined relative to hematite at 300 K and 77 K by Mössbauer spectroscopy. Using the relative recoil-free fractions compared to that of hematite, the relative recoilless fractions between all pairs of the seven iron oxides were determined. The F-values can allow conversion of Mössbauer subspectral areas to the relative atomic, molecular, or weight fractions of each iron oxide present in a mixed oxide phase sample.


Displacement-Based Analysis And Design Of Rigid Retaining Walls During Earthquakes, Yingwei Wu Jan 1999

Displacement-Based Analysis And Design Of Rigid Retaining Walls During Earthquakes, Yingwei Wu

Doctoral Dissertations

"This research focused on the analysis and design of rigid retaining walls subjected to earthquakes and considered nonlinear foundation soil properties. The simultaneous sliding and rocking movements of retaining walls were considered. Seven field conditions, including moist, submerged, perched and saturated backfill with a sloping drain, were specified by design codes. A computer program capable of computing displacement using real time history records or equivalent sinusoidal motions was developed. Finally, a dynamic design procedure was proposed for practicing engineers.

The study revealed that maximum shear modulus in foundation soil, maximum ground acceleration, and soil nonlinearity had significant effect on the …


Machine Tool Accuracy Characterization, Error Modeling And Compensation Using Telescopic Ballbar And Laser Interferometer, Yalcin M. Ertekin Jan 1999

Machine Tool Accuracy Characterization, Error Modeling And Compensation Using Telescopic Ballbar And Laser Interferometer, Yalcin M. Ertekin

Doctoral Dissertations

"This dissertation presents the results of the research investigation on the machine tool accuracy characterization, error modeling and error compensation using telescopic ballbar and laser interferometer. Increasing demand for both higher machine tool accuracy and machining tolerances has resulted in a great need to measure and characterize the accuracy of NC machine tools and minimize machine tool induced errors on machined components before manufacturing parts, instead of inferring it from parts already machined. Using a telescopic magnetic ballbar, the results of the accuracy assessment of an old Bridgeport Series I CNC 2 1/2 axes vertical machining center are presented in …


Constructive Induction Machines For Data Mining, Marek Perkowski, Stanislaw Grygiel, Qihong Chen, Dave Mattson Jan 1999

Constructive Induction Machines For Data Mining, Marek Perkowski, Stanislaw Grygiel, Qihong Chen, Dave Mattson

Electrical and Computer Engineering Faculty Publications and Presentations

"Learning Hardware" approach involves creating a computational network based on feedback from the environment (for instance, positive and negative examples from the trainer), and realizing this network in an array of Field Programmable Gate Arrays (FPGAs). Computational networks can be built based on incremental supervised learning (Neural Net training) or global construction (Decision Tree design). Here we advocate the approach to Learning Hardware based on Constructive Induction methods of Machine Learning (ML) using multivalued functions. This is contrasted with the Evolvable Hardware (EHW) approach in which learning/evolution is based on the genetic algorithm only. Various approaches to supervised inductive learning …


Logic Synthesis For A Regular Layout, Marek Perkowski, Yang Xu, Malgorzata Chrzanowska-Jeske Jan 1999

Logic Synthesis For A Regular Layout, Marek Perkowski, Yang Xu, Malgorzata Chrzanowska-Jeske

Electrical and Computer Engineering Faculty Publications and Presentations

New algorithms for generating a regular two-dimensional layout representation for multi-output, incompletely specified Boolean functions, called, Pseudo-Symmetric Binary Decision Diagrams (PSBDDs), are presented. The regular structure of the function representation allows accurate prediction of post-layout areas and delays before the layout is physically generated. It simplifies power estimation on the gate level and allows for more accurate power optimization. The theoretical background of the new diagrams, which are based on ideas from contact networks, and the form of decision diagrams for symmetric functions is discussed. PSBDDs are especially well suited for deep sub-micron technologies where the delay of interconnections limits …


Grazing Reflection Of Gaussian Beams, Lee W. Casperson Jan 1999

Grazing Reflection Of Gaussian Beams, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

The reflectivities of most surfaces are higher for grazing or near-90-deg angles of incidence than for more perpendicular or near-zero-deg angles. Grazing-incidence configurations are especially important in the development of lasers and optical systems that operate in the far-ultraviolet and soft-x-ray regions of the spectrum, where transparent or highly reflecting media are almost unknown. Analytical solutions of the paraxial wave equation are obtained for the grazing reflection and complex interference effects that take place when a Gaussian beam interacts at shallow angles with a reflecting surface.


Head Movement And Vision In Underwater-Feeding Birds Of Stream, Lake, And Seashore, Lee W. Casperson Jan 1999

Head Movement And Vision In Underwater-Feeding Birds Of Stream, Lake, And Seashore, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

Studies head movement and vision in underwater-feeding birds. Review of relevant literature on the physiological and behavioral aspects of vision; Role of vertical head movement as an aid in the acquisition of visual information.


Conjunctive Use Of Surface Water And Groundwater For Sustainable Agricultural Production, Richard C. Peralta Jan 1999

Conjunctive Use Of Surface Water And Groundwater For Sustainable Agricultural Production, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

This report is a guide to aid conjunctive water use in stream-aquifer systems. Conjunctive use refers to coordinated use of groundwater and surface water resources. This document discusses principles useful for field engineers and agricultural experts. It presents hydrologic and hydraulic principles and quantitative and qualitative parameters relating to sustainable conjunctive use. It provides tools and software.


Developing Database Applications By Using Software Components, Nusret Conk Jan 1999

Developing Database Applications By Using Software Components, Nusret Conk

College of Graduate Studies: Theses & Dissertations (1964–2006)

Today, the software application development process is more assembly work than a "build from scratch" approach. By placing pre-existing software components together, it is possible to create a complete application. Such components provide interfaces so that programs use them for their intended purposes. The objective of this thesis is to illustrate how software components work together to make a complete application. To illustrate the ideas and the components, this project presents a three-tiered web database application. This application, as a whole, is made up of the client side web browser, a database and the actual application programs which are Java …


Implementation And Performance Study Of Image Data Hiding/Watermarking Schemes, Arkadiusz Edward Komenda Jan 1999

Implementation And Performance Study Of Image Data Hiding/Watermarking Schemes, Arkadiusz Edward Komenda

Theses

Two data hiding / watermarking techniques for grayscale and color images are presented. One of them is DCT based, another uses DFT to embed data. Both methods were implemented in software utilizing C/C++. The complete listings of these programs are included. A comprehensive reliability analysis was performed on both schemes, subjecting watermarked images to JPEG, SPIRT and MPEG-2 compressions. In addition, the pictures were examined by exposing them to common signal processing operations such as image resizing, rotation, histogram equalization and stretching, random, uniform and Gaussian noise addition, brightness and contrast variations, gamma correction, image sharpening and softening, edge enhancement, …


Time-Resolved Reflection High-Energy Electron Diffraction Study Of The Ge(111)-C(2×8)-(1×1) Phase Transition, Xinglin Zeng, Bo Lin, Ibrahim El-Kholy, Hani E. Elsayed-Ali Jan 1999

Time-Resolved Reflection High-Energy Electron Diffraction Study Of The Ge(111)-C(2×8)-(1×1) Phase Transition, Xinglin Zeng, Bo Lin, Ibrahim El-Kholy, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

The dynamics of the Ge(111)-c(2×8)-(1×1) phase transition is investigated by 100-ps time-resolved reflection high-energy electron diffraction. A laser pulse heats the surface while a synchronized electron pulse is used to obtain the surface diffraction pattern. Slow heating shows that the adatoms in Ge(111)-c(2×8) start to disorder at ∼510 K and are converted to a disordered adatom arrangement at 573 K. For heating with 100-ps laser pulses, the Ge(111)-c(2×8) reconstructed adatom arrangement starts to disorder at 584±16K, well above the onset temperature of ∼510 K for the disordering of Ge(111)-c(2×8) observed for slow …


An Algorithm For Optimal Winner Determination In Combinatorial Auctions, Tuomas Sandholm Jan 1999

An Algorithm For Optimal Winner Determination In Combinatorial Auctions, Tuomas Sandholm

All Computer Science and Engineering Research

Combinatorial auctions, i.e. auctions where bidders can bid on combinations of items, tend to lead to more efficient allocations than traditional auctions in multi-item auctions where the agents' valuations of the items are not additive. However, determining the winners so as to maximize revenue is NP-complete. First, existing approaches for tackling this problem are reviewed: exhaustive enumeration, dynamic programming, approximation algorithms, and restricting the alloable combinations. Then we present our search algorithm for optimal winner determination. Experiments are shown on several bid distributions. The algorithm allows combinatorial auctions to scale up to significantly larger numbers of items and bids than …


Auctions Without Common Knowledge, Sviatoslav B. Brainov, Tuomas W. Sandholm Jan 1999

Auctions Without Common Knowledge, Sviatoslav B. Brainov, Tuomas W. Sandholm

All Computer Science and Engineering Research

This paper proves that the revenue equivalence theorem ceases to hold for auctions without common knowledge about the agents' prior beliefs. That is, different auction forms yield different expected revenue. To prove this, an auction game is converted to a Bayesian decision problem with an infinite hierarchy of beliefs. A general solution for such Bayesian decision problems is proposed. The solution is a generalization of the standard Bayesian solution and coincides with it for finite belief trees and for trees representing common knowledge. It is shown how the solution generalizes the frequently used technique of backward induction for infinite belief …


Design Issues For High Performance Active Routers, Tilman Wolf, Jonathan Turner Jan 1999

Design Issues For High Performance Active Routers, Tilman Wolf, Jonathan Turner

All Computer Science and Engineering Research

Active networking is a general approach to incorporating general-purpose computational capabilities within the communications infrastructure of data networks. This paper proposes a design of a scalable, high performance active router. This is used as a vehicle for studying the key design issues that must be resolved to allow active networking to become a mainstream technology.


Algorithms For Optimizing Leveled Commitment Contracts, Thomas Sandholm, Sandeep Sikka, Samphel Norden Jan 1999

Algorithms For Optimizing Leveled Commitment Contracts, Thomas Sandholm, Sandeep Sikka, Samphel Norden

All Computer Science and Engineering Research

In automated negotiation systems consisting of self-interested agents, contracts have traditionally been binding. Leveled commitment contracts - i.e. contracts where each party can decommit by paying a predetermined penalty - were recently shown to improve Pareto efficiency even if agents rationally decommit in Nash equilibrium using inflated thresholds on how good their outside offers must be before they decommit. This paper operationalizes the four leveled commitment contracting protocols by presenting algorithms for using them. Algorithms are presented for computing the Nash equilibrium decomitting thresholds and decommitting probabilities given the contract price and the penalties. Existence and uniqueness of the equilibrium …


Tracking Mobile Units For Dependable Message Delivery, Amy L. Murphy, Gruia-Catalin Roman, George Varghese Jan 1999

Tracking Mobile Units For Dependable Message Delivery, Amy L. Murphy, Gruia-Catalin Roman, George Varghese

All Computer Science and Engineering Research

As computing components get smaller and people become accustomed to having computational power at their disposal at any time, mobile computing is developing as an important research area. One of the fundamental problems in mobility is maintaining connectivity through message passing as the user moves through the network. An approach to this is to have a single home node constantly track the current location of the mobile unit and forward messages to this location. One problem with this approach is that during the update to the home agent after movement, messages are often dropped, especially in the case of frequent …


Floor Control Protocol For Alx Video Conference Application, Ruibiao Qiu Jan 1999

Floor Control Protocol For Alx Video Conference Application, Ruibiao Qiu

All Computer Science and Engineering Research

With wide deployment of high-speed networks such as vBNS today, video-conference applications over WANs have become increasingly feasible. MMX has proven to be a good desktop video-conference devide for local ATM networks. Now, ALX has been designed to extend MMX's video conferencing capability to IP-over-ATM WANs such as vBNS. In this report, we discuss a floor control protocol for ALX video-conference applications. We first show how an "ideal" protocol should behave to meet our requirements. Then we compare three protocols based on distributed algorithms, and a protocol based on a centralized algorithm. Based on the comparison and performance analysis, we …


Software Engineering For Mobility: A Roadmap, Gruia-Catalin Roman, Gian Pietro Picco, Amy L. Murphy Jan 1999

Software Engineering For Mobility: A Roadmap, Gruia-Catalin Roman, Gian Pietro Picco, Amy L. Murphy

All Computer Science and Engineering Research

The term distributed computing conjures the image of a fixed network structure whose nodes support the execution of processes that communicate with each other via messages traveling along links. Peer-to-peer communication is feasible but client-server relationships dominate. More recently, servers have been augmented with brokerage capabilities to facilitate discovery of available services. Stability is the ideal mode of operation; changes are relatively slow; even in the case of failure, nodes and links are expected eventually to come back up. By contrast, mobility represents a total meltdown of all the stability assumptions (explicit or implicit) associated with distributed computing. The network …


Bargaining With Deadlines, Tuomas Sandholm, Nir Vulkan Jan 1999

Bargaining With Deadlines, Tuomas Sandholm, Nir Vulkan

All Computer Science and Engineering Research

This paper analyzes automated distributive negotiation where agents have firm deadlines that are private information. The agents are allowed to make and accept offers in any order in continuous time. We show that the only sequential equilibrum outcome is the one where the agents wait until the first deadline, at which point that agent concedes everything to the other. This holds for pure and mixed strategies. So, interestingly, rational agents can never agree to a nontrivial split because offers signal enough weakness of bargaining power (early deadline) so that the recipient should never accept. Similarly, the offerer knows that it …


On The Global Stabilization Of Nonlinear Systems Via Switching Manifolds, Stephen P. Banks, Meti̇n U. Salamci, M. Kemal Özgören Jan 1999

On The Global Stabilization Of Nonlinear Systems Via Switching Manifolds, Stephen P. Banks, Meti̇n U. Salamci, M. Kemal Özgören

Turkish Journal of Electrical Engineering and Computer Sciences

The global stabilization of nonlinear systems is investigated by using switching surfaces. The nonlinear system is forced to a lower order switching manifold, which is designed to be stable by construction. Thus, the stability of the reduced-order system is guaranteed and parameter selection for the switching surface is avoided. The method is extended to a class of uncertain nonlinear systems and exemplified with some fictitious dynamic models.


A Simple Formula Obtained Using Tabu Search Algorithm For The Radiation Efficiency Of A Resonant Rectangular Microstrip Antenna, Dervi̇ş Karaboğa, Keri̇m Güney Jan 1999

A Simple Formula Obtained Using Tabu Search Algorithm For The Radiation Efficiency Of A Resonant Rectangular Microstrip Antenna, Dervi̇ş Karaboğa, Keri̇m Güney

Turkish Journal of Electrical Engineering and Computer Sciences

A new simple formula for the radiation efficiency of a resonant rectangular microstrip patch antenna is presented. The formula is obtained by using a tabu search algorithm, which is a quite new optimization technique based on the principles of intelligent problem solving. The formula is valid for substrates with relative permittivities between 1 and 12.8 and for the complete range of thicknesses normally used. The results obtained by using this new simple formula are in conformity with those reported elsewhere. The formula can also be used in the calculation of the radiation efficiency of dipoles.