Engineering Commons^™

Router Plugins: A Modular And Extensible Software Framework For Modern High Performance Integrated Services Routers, Dan Decasper, Zubin Dittia, Guru Parulkar, Bernhard Plattner

All Computer Science and Engineering Research

Present day routers typically employ monolithic operating systems which are not easily upgraded and extensible. WIth the rapid rate of protocol development it is becoming increasingly important to dynamically upgrade router software in an incremental fashion. We have designed and implemented a high performance, modular, extended integrated services router software architecture in the NetBSD operating system kernel. This architecture allows code modules, called plugins, to be dynamically added and configured at run time. One of the novel features of our design is the ability to bind different plugins to individual flows; this allows for distinct plugin implementations to seamlessly coexist …

Terabit Burst Switching Progress Report (12/97-2/98), Jonathan S. Turner

All Computer Science and Engineering Research

This report summarizes progress on the Terabit Burst Switching Project at Washington University for the period from December 15, 1997 through March 15, 1998. Efforts during this period have concentrated on working out details of the burst switch architecture, evaluating a variety of implementation alternatives and developing the physical design of the 160 Gb/s ATM switch to allow demonstration of the burst switch within a realistic network context.

Integrating A Constraint Mechanism With The Javabeans Model, William M. Shapiro

All Computer Science and Engineering Research

The JavaBeans component model allows users to plug together software components to create Java applications by specifying simple relationships between component events and properties. This paper describes work on augmenting the simple JavaBeans model with a multi-way constraint mechanism that allows users to graphically specify more complex multi-way contraints, resolve cyclical constraints between bean properties and graphically layout bean components. We also discuss weaknesses in the JavaBeans model and Java Abstract Windowing Toolkit (AWT) that were discovered while integrating a constraint mechanism with JavaBeans.

Lime: Linda Meets Mobility, Gian Pietro Picco, Amy L. Murphy, Gruia-Catalin Roman

All Computer Science and Engineering Research

LIME is a system designed to assist in the rapid development of dependable mobile applications over both wired and ad hoc networks. Mobile agents reside on mobile hosts and all communication takes place via transiently shared tuple spaces distributed across the mobile hosts. The decoupled style of computing characterizing the Linda model is extended to the mobile environment. At the application level, both agents and hosts perceive movement as a sudden change of context. The set of tuples accessible by a particular agent residing on a given host is altered transparently in response to changes in the connectivity pattern among …

Tcp Dynamic Acknowledgment Delay: Theory And Practice, Daniel R. Dooly, Sally A. Goldman, Stephen D. Scott

All Computer Science and Engineering Research

We study an on-line problem that is motivated by the networking problem of dynamically adjusting delays of acknowledgments in the Transmission Control Protocol (TCP). The theoretical problem we study is the following. There is a sequence of n packet arrival times A = and a look-ahead coefficient L. The goal is to partition A into k subsequences sigma1, sigma2, ...,sigmak (where a subsequence end is defined by an acknowledgment) that minimizes a linear combination of the cost for the number of acknowledgments sent and the cost for the additional latency introduced by delaying acknowledgments. At each arrival, an oracle provides …

The Playground Mediator: Visual Tool For Configuring And Debugging Distributed Applications, T. Paul Mccartney

All Computer Science and Engineering Research

The Mediator is a visual configuration tool for use with The Programmers' Playground distributed programming environment. With the Mediator, one can interactively launch distributed application modules, configured communication among the modules, observe communication patterns, interactively control module communication, kill running modules, and receive imported applications from a separate World Wide Web interface. This manual describes how to use the Mediator both as a stand-alone configuration tool and as a visual interface to the Playground Application Management System.

An Mdo-Compatible Method For Robust Design Of Vehicles, Systems, And Components, Leslie D. Liaw, Richard I. Devries, Donald L. Cronin

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A CAE simulation process was developed to quantify the variability of vehicle attributes such as safety, durability, vehicle dynamics, NVH and weight. The process was integrated with the Ford multi-function optimization (MFO) tool — MOVE (Multi-Function Optimization Visualization Environments) in order to facilitate the robust design of vehicles, systems and components. The statistics of vehicle attribute responses are computed given the statistics of the design parameters. The response surface approximation was used to simplify the input and output relationships. A variety of statistical distributions can be selected to match the statistics of the design parameters which are continuous or discrete. …

Belted Work Machine, J. J. Burckhartzmeyer, E. R. Crabb, T. F. Lehnhoff, A. L. Watson Jr.

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A heavy duty belt laying work machine includes a frame, a driver wheel mounted in supporting relation to the frame on each lateral side thereof, an idler wheel assembly disposed on each lateral side of the frame. The idler wheel assembly includes an idler wheel and a carry-roller, each of which is rotatably connected to an idler support arm that is pivotally mounted in supporting relation to the frame. A mid-roller is disposed on each lateral side of the frame between the driver wheel and the idler wheel assembly and rotatably connected to a mid-roller support arm mounted in supporting …

Integrating Security Into The Curriculum, Cynthia E. Irvine, Shiu-Kai Chin, Deborah Frincke

Electrical Engineering and Computer Science - All Scholarship

The number of skilled practitioners of computer security who are able to address the complexities of modern technology and are familiar with successful approaches to system security is very small. People want security but are faced with two difficulties. First, they do not know how to achieve it in the context of their enterprises. They may not even know of a way to translate organizational procedures into policies, much less implement a set of mechanisms to enforce those policies. Second, they have no way of knowing whether their chosen mechanisms are effective. The recent US Presidential Commission on Critical Infrastructure …

Metal-Organic Chemical Vapor Deposition Of Sr-Co-Fe-O Films On Porous Substrates, C.-F. Xia, P. Atanasova, Robert W. Schwartz, T. L. Ward

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Aerosol-assisted chemical vapor deposition using the b-diketonate precursors Sr(tmhd)2•2H2O, Fe(tmhd)3 and Co(tmhd)3 was investigated for depositing thin films of the mixed-conducting ceramic SrCoyFe1-yO3-d onto porous a-Al2O3 substrates. Single-phase SrCoyFe1-yO3-d perovskite films were obtained at a deposition temperature of 550°C and pressure of 15 mm Hg, whereas deposition at atmospheric pressure produced mixed-phase films. The Co/Fe elemental ratios in the films reflected those in the precursor solution, but the films were depleted in Sr. Reduced-pressure deposition provided a more uniform film morphology than atmospheric-pressure, and led to a supported film which was leak-tight to N2 flow.

Robustness Analysis Of Hopfield And Modified Hopfield Neural Networks In Time Domain, Jie Shen, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A variant of the Hopfield network, called the modified Hopfield network is formulated. This network which consists of two mutually recurrent networks has more free parameters than the well-known Hopfield network. Stability analysis of this network is presented. The analysis is carried out in the time domain with an application of the Lyapunov method and robust control Lyapunov function. The current flow in the network is treated as a "control". This "controller" is shown to guarantee "a practically stabilizing control". Analysis of the Hopfield network is also included for completion.

University Of Texas At Tyler Freshman Catalog, 1998-1999, University Of Texas At Tyler

Catalogs

Archives Space instance: https://archivesspace.uttyler.edu/repositories/2/archival_objects/22363

Test 1747: John Deere 8400t Diesel 16-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF THE TEST PROCEDURE

General

Tractors are tested at the University of Nebraska according to the Agricultural Tractor Test Code approved by the American Society of Agricultural Engineers and the Society of Automotive Engineers or official Nebraska test procedure.

The manufacturer selects the tractor to be tested and certifies that it is a stock model. Each tractor is equipped with the common power consuming accessories such as power steering, power lift pump, generator, etc., if available. Power consuming accessories may be disconnected only when the means for disconnecting can be reached from the operating station. An official representative of …

Test 1748: Caterpiller Challenger 65e Diesel 10-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF THE TEST PROCEDURE

General

Tractors are tested at the University of Nebraska according to the Agricultural Tractor Test Code approved by the American Society of Agricultural Engineers and the Society of Automotive Engineers or official Nebraska test procedure.

The manufacturer selects the tractor to be tested and certifies that it is a stock model. Each tractor is equipped with the common power consuming accessories such as power steering, power lift pump, generator, etc., if available. Power consuming accessories may be disconnected only when the means for disconnecting can be reached from the operating station. An official representative of …

Test 1752: Agco Allis 9745 Diesel 18-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF THE TEST PROCEDURE

General

Tractors are tested at the University of Nebraska according to the Agricultural Tractor Test Code approved by the American Society of Agricultural Engineers and the Society of Automotive Engineers or official Nebraska test procedure.

The manufacturer selects the tractor to be tested and certifies that it is a stock model. Each tractor is equipped with the common power consuming accessories such as power steering, power lift pump, generator, etc., if available. Power consuming accessories may be disconnected only when the means for disconnecting can be reached from the operating station. An official representative of …

Test 1754: John Deere 5210 Diesel 9-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF THE TEST PROCEDURE General Tractors are tested at the University of Nebraska according to the Agricultural Tractor Test Code approved by the American Society of Agricultural Engineers and the Society of Automotive Engineers or official Nebraska test procedure. The manufacturer selects the tractor to be tested and certifies that it is a stock model. Each tractor is equipped with the common power consuming accessories such as power steering, power lift pump, generator, etc., if available. Power consuming accessories may be disconnected only when the means for disconnecting can be reached from the operating station. An official representative of …

Test 1755: John Deere 5310 Diesel 9-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF THE TEST PROCEDURE General Tractors are tested at the University of Nebraska according to the Agricultural Tractor Test Code approved by the American Society of Agricultural Engineers and the Society of Automotive Engineers or official Nebraska test procedure. The manufacturer selects the tractor to be tested and certifies that it is a stock model. Each tractor is equipped with the common power consuming accessories such as power steering, power lift pump, generator, etc., if available. Power consuming accessories may be disconnected only when the means for disconnecting can be reached from the operating station. An official representative of …

Test 1756: John Deere 5410 Diesel 9-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF THE TEST PROCEDURE General Tractors are tested at the University of Nebraska according to the Agricultural Tractor Test Code approved by the American Society of Agricultural Engineers and the Society of Automotive Engineers or official Nebraska test procedure. The manufacturer selects the tractor to be tested and certifies that it is a stock model. Each tractor is equipped with the common power consuming accessories such as power steering, power lift pump, generator, etc., if available. Power consuming accessories may be disconnected only when the means for disconnecting can be reached from the operating station. An official representative of …

Development And Saw Device Implementation Of A New Weighted Stepped Chirp Code Signal For Direct Sequence Spread Spectrum Communications Systems, Scott Edward Carter

Retrospective Theses and Dissertations

This work introduces the new weighted stepped chirp code signal for direct sequence spread spectrum (DS/SS) communications systems. This code signal uses the truncated cosine series functions as the chip functions. This code signal is the result of discretizing a continuous wave (CW) chirp which results in enhanced performance versus a pseudonoise (PN) code and equivalent performance and easier implementation than a CW chirp. This code signal will be shown to possess improved compression ratio (CR), peak sidelobe level (PSL), integrated sidelobe level (ISL), and bit error rate (BER) when compared to a PN code of identical code length and …

Building A Secure Intranet, Fred J. Berryman

Theses

This thesis will explain the vulnerabilities of computers in a networking environment and demonstrate proper procedures for building a secure Intranet.

The Internet is built around the concept of open communication. Data is shared around the globe just as easily as it is from one office or cubical to the next. Corporations are skeptical about putting company data on such a public transport mechanism as the Internet, but the tools used on the Internet are exciting and everyone wants to use them. Out of a desire for the best of both worlds, the Intranet was born.

An intranet that has …

Simulation Studies With A Continuously Online Trained Artificial Neural Network Controller For A Micro-Turbogenerator, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

This paper reports on the simulation studies carried out using MATLAB/SIMULINK and the practical implementation of a continuously online trained (COT) artificial neural network (ANN) controller to identify the continuous changing complex nonlinear dynamics of the power system, and another COT ANN to control a micro-turbogenerator which consists of a turbine simulator and a micro-alternator connected to an infinite bus through a short transmission line in a laboratory environment. This neural network controller augments/replaces the traditional automatic voltage regulator (AVR) and the turbine governor of the generator. Simulation and practical results are presented to show that this COT ANN identifier/controller …

Millimeter Wave Signals Detection By Means Of Monocrystal Hexagonal Ferrite Ellipsoid, Marina Koledintseva, Alexander A. Kitaytsev

Electrical and Computer Engineering Faculty Research & Creative Works

Stable nonlinear resonance effects (SNLREs) have been already studied in crystallographically "isotropic" ferrogarnet ferrite resonators (FR), employed as microwave detectors in the frequency range of 300 MHz to 30 GHz. Application of prospective hexagonal monocrystal ferrites with large field of crystallographic magnetic anisotropy leads to the possibility of a gyromagnetic converter (GC) design for mm waveband (from 30 to 200 GHz) without massive external magnets. This paper deals with the analysis of a more general case with taking into account both crystallographic and form anisotropy as well as the arbitrary orientation of the main crystallographic axis with respect to the …

Substroke Matching By Segmenting And Merging For Online Korean Cursive Character Recognition, Chang-Soo Kim, Kang Ryoung Park, Byung Hwan Jun, Jaihie Kim

Electrical and Computer Engineering Faculty Research & Creative Works

The Korean character is composed of several alphabets in two-dimensional formation and the total number of Korean characters exceeds eleven thousand. Therefore, the previous approaches to Korean cursive characters pay most of their attention to segmenting a character into alphabets accurately. However, it is difficult because the boundaries of alphabets are not apparent in most cases. We propose an alphabet-based method without assuming accurate alphabet segmentation. In the proposed method, a cursive character is segmented into substrokes by a set of segmenting conditions. Then it is matched with the reference substrokes generated from alphabet models and ligatures by segmenting and …

Deuterium Nmr Of Adsorbed Poly(Methyl Acrylate)-D₃, Frank D. Blum, Wuu-Yung Lin

Chemistry Faculty Research & Creative Works

The dynamics of polymers at interfaces are important in a variety of applications, especially where those applications depend on the mechanical or surface properties. Unfortunately, the surface properties of interfacial species like polymers used in composites are not easily measured macroscopically. Microscopic techniques, especially spectroscopic ones, have been successful. In our laboratory we have been successful in applying NMPR to determine the behavior of absorbed polymers. NMR has several advantages for this kind of study, the principal ones being that it can be used on opaque materials, different nuclei can be used as probes, and interfacial material can sometimes be …

A Maximum Torque Per Ampere Control Strategy For Induction Motor Drives, O. Wasynczuk, Keith Corzine, S. D. Sudhoff, Jerry L. Tichenor, P. C. Krause, I. G. Hansen, L. M. Taylor

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a new control strategy is proposed which is simple in structure and has the straightforward goal of minimizing the stator current amplitude for a given load torque. It is shown that the resulting induction motor efficiency is reasonably close to optimal and that the approach is insensitive to variations in rotor resistance. Although the torque response is not as fast as in field-oriented (FO) control strategies, the response is reasonably fast. In fact, if the mechanical time constant is large relative to the rotor time constant, which is frequently the case, the sacrifice in dynamic performance is …

An Automated State Model Generation Algorithm For Simulation/Analysis Of Power Systems With Power Electronic Components, Steven Pekarek, E. A. Walters, T. L. Skvarenina, O. Wasynczuk

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a recently developed algorithmic method of deriving the state equations of power systems containing power electronic components is described. Therein the system is described by the pertinent branch parameters and the circuit topology; however, unlike circuit-based algorithms, the difference equations are not implemented at the branch level. Instead, the composite system state equations are established. A demonstration of the computer implementation of this algorithm to model a variable-speed, constant-frequency aircraft generation system is described. Because of the large number of states and complexity of the system, particular attention is placed on the development of a model structure …

Simulation Of Madmel Power Systems Components, Timothy L. Skvarenina, Oleg Wasynczuk, Paul C. Krause, Steven Pekarek

Electrical and Computer Engineering Faculty Research & Creative Works

Detailed computer models of system components for More Electric Aircraft have been developed using the Advanced Control System Language (ACSL) and its graphical front-end, Graphic Modeller. Among the devices modeled are a wound-rotor synchronous generator with parallel bridge-rectifier outputs, a switched-reluctance generator, and various loads including a DC-DC converter, an inverter-driven induction motor, and an electro-hydrostatic actuator. Results from the simulations are presented together with corroborating experimental test results. Copyright © 1998 Society of Automotive Engineers, Inc.

Dc Link Stabilized Field Oriented Control Of Electric Propulsion Systems, Keith Corzine, S. D. Sudhoff, Steven F. Glover, H. J. Hegner, H. N. Robey

Electrical and Computer Engineering Faculty Research & Creative Works

Induction motor based electric propulsion systems can be used in a wide variety of applications including locomotives, hybrid electric vehicles, and ships. Field oriented control of these drives is attractive since it allows the torque to be tightly and nearly instantaneously controlled. However, such systems can be prone to negative impedance instability of the DC link. This paper examines this type of instability and sets forth a readily implemented albeit nonlinear control strategy to mitigate this potential problem.

A Practical Continually Online Trained Artificial Neural Network Controller For A Turbogenerator, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

This paper reports on the simulation and practical studies carried out on a single turbogenerator connected to an infinite bus through a short transmission line, with a continually online trained (COT) artificial neural network (ANN) controller to identify the turbogenerator, and another COT ANN to control the turbogenerator. This identifier/controller augments/replaces the automatic voltage regulator and the turbine governor. Results are presented to show that this COT ANN identifier/controller has the potential to allow turbogenerators to operate more closely to their steady-state stability limits and nevertheless “ride through” severe transient disturbances such as three phase faults. This allows greater usage …

Open Hemispherical Imaging Dielectric Resonator With Whispering Gallery Modes, Sergey Kharkovsky, Z. E. Eremenko, Yuri F. Filipov

Electrical and Computer Engineering Faculty Research & Creative Works

The imaging dielectric resonators with whispering gallery modes (WGMs) for the creation of a new class of millimeter wave solid-state oscillators, devices for the investigation of high temperature superconductors, were suggested. They contain a dielectric element as a semidisk or a cylinder or a hemisphere and a flat metal mirror. The latter is a necessary element for placing in the resonator field active elements or conductor samples of materials. There is an important question about the dependence of the resonant frequencies and Q-factor of these resonators on impedance of the resonator mirror. In the present paper new investigation results of …