Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Faculty Publications

Discipline
Institution
Keyword
Publication Year
File Type

Articles 11581 - 11610 of 12156

Full-Text Articles in Entire DC Network

Low Cost Schottky Barrier Solar Cells Fabricated On Cdse And Sb2S3 Films Chemically Deposited With Silicotungstic Acid, O. Savadogo, K. C. Mandal Oct 1994

Low Cost Schottky Barrier Solar Cells Fabricated On Cdse And Sb2S3 Films Chemically Deposited With Silicotungstic Acid, O. Savadogo, K. C. Mandal

Faculty Publications

No abstract provided.

Go to article

Automating Workflows For Service Provisioning: Integrating Ai And Database Technologies, Munindar P. Singh, Michael N. Huhns Oct 1994

Automating Workflows For Service Provisioning: Integrating Ai And Database Technologies, Munindar P. Singh, Michael N. Huhns

Faculty Publications

Workflows are the structured activities that take place in information systems in typical business environments. These activities frequently involve several database systems, user interfaces, and application programs. Traditional database systems do not support workflows to any reasonable extent: usually human beings must intervene to ensure their proper execution. We have developed an architecture based on AI technology that automatically manages workflows. This architecture, which executes on top of a distributed computing environment, has been applied to automating service provisioning workflows; an implementation that operates on one such workflow has been developed. This work advances the Carnot Project’s goal of developing …

Go to article

Thomas Hobbes's "A Discourse Of Laws", Noel B. Reynolds Sep 1994

Thomas Hobbes's "A Discourse Of Laws", Noel B. Reynolds

Faculty Publications

The recent discovery that an anonymously published 1620 essay was an early writing of Thomas Hobbes invites investigation of his early thinking. Hobbes relied on mostly classical sources to advance a basically conventionalist theory of law and to anticipate twentieth century analyses of the principles of rule of law such as that made famous by F. A. Hayek.

Go to article

Performance Analysis Of Antennas For Hand-Held Transceivers Using Fdtd, Michael A. Jensen, Yahya Rahmat-Samii Aug 1994

Performance Analysis Of Antennas For Hand-Held Transceivers Using Fdtd, Michael A. Jensen, Yahya Rahmat-Samii

Faculty Publications

The design of antennas for hand-held communications devices depends on the implementation of simulation tools that can accurately model general topologies. The paper presents the analysis of small antennas mounted on hand-held transceivers using the finite-difference time-domain (FDTD) method. The key features of the FDTD implementation are discussed, with particular emphasis placed upon modeling of the source region. The technique is used to predict the gain patterns and broadband input impedance behavior of monopole, planar inverted F, and loop antenna elements mounted on the handset. Effects of the conducting handset chassis, the plastic casing around the device, and lumped elements …

Go to article

Characterization Of The Near-Interface Region Of Chemical Vapor Deposited Diamond Films On Silicon By Backscatter Kikuchi Diffraction, Brent L. Adams, K. Kunze, S. Geier, R. Hessmer, B. Rauschembach, M. Schreck, B. Stritzker Jul 1994

Characterization Of The Near-Interface Region Of Chemical Vapor Deposited Diamond Films On Silicon By Backscatter Kikuchi Diffraction, Brent L. Adams, K. Kunze, S. Geier, R. Hessmer, B. Rauschembach, M. Schreck, B. Stritzker

Faculty Publications

B.L.A. and K.K. gratefully acknowledge support under a Materials Research Group Award by the National Science Foundation No. DMR-9001278. Also the software support by Th. Bollmeier is greatly appreciated. The lattice orientations near the interface of chemical vapor deposited diamond films on Si(001) have been studied by orientation imaging microscopy. This technique is based on the automated analysis of electron backscatter Kikuchi diffraction patterns. The electron beamhas been scanned in discrete steps over the reverse side of the diamond film after having removed the substrate. The obtained data have allowed us to determine the texture and to visualize quantitatively the …

Go to article

The Asymptotic Structure Of Transient Elastodynamic Fields At The Tip Of A Stationary Crack, Xiaomin Deng Jul 1994

The Asymptotic Structure Of Transient Elastodynamic Fields At The Tip Of A Stationary Crack, Xiaomin Deng

Faculty Publications

The asymptotic structure of the transient elastodynamic near-tip fields around a stationary crack is investigated for all three fracture modes. The transient fields are obtained as the sum of their quasi-static counterparts and corresponding transient correction terms, in terms of variable-separable expansions. By allowing the coefficients of terms in the quasi-static expansion to deviate from their quasi-static restrictions, the correction terms are shown to be the particular solutions of a set of first order (for mixed mode I and II) or second order (for mode III) ordinary differential equations with constant coefficients and non-homogeneous terms involving only sine and cosine …

Go to article

A Functional Architecture For Automated Highway Traffic Planning, H.-S. Jacob Tsao Jul 1994

A Functional Architecture For Automated Highway Traffic Planning, H.-S. Jacob Tsao

Faculty Publications

In a fully automated Automated Highway System (AHS), the roadside control system and the vehicles themselves are responsible for moving the large number of vehicles safely and efficiently. Therefore, the task of operating an AHS is drastically different from and much more complex than its conventional counterpart. Resulting from a large number of design options, there exist many possible ways to operate an AHS. Each of these possible operating scenarios will support a different set of functions. A crucial task in AHS R&D is to evaluate and compare these potentially large number of different AHS operating scenarios with respect to …

Go to article

Caid Currents: The State Of Caid Art, Del Coates Jul 1994

Caid Currents: The State Of Caid Art, Del Coates

Faculty Publications

No abstract provided.

Go to article

Defense Industrial Base Policy: Revisited, Michael E. Heberling Jul 1994

Defense Industrial Base Policy: Revisited, Michael E. Heberling

Faculty Publications

In an era of decreasing defense budgets and enemy threats, problems associated with maintaining a healthy defense industrial base have become pronounced. This article discussed defense industrial policy goals and argues that these goals may be collectively unobtainable.

Go to article

Technology Comes To The Courtroom, And . . ., Fredric I. Lederer Jul 1994

Technology Comes To The Courtroom, And . . ., Fredric I. Lederer

Faculty Publications

No abstract provided.

Go to article

The Proper Legal Regime For 'Cyberspace', I. Trotter Hardy Jul 1994

The Proper Legal Regime For 'Cyberspace', I. Trotter Hardy

Faculty Publications

No abstract provided.

Go to article

Inversion Of Light Scattering Measurements For Particle Size And Optical Constants: Theoretical Study, Matthew R. Jones, Bill P. Curry, M. Quinn Brewster, Keng H. Leong Jun 1994

Inversion Of Light Scattering Measurements For Particle Size And Optical Constants: Theoretical Study, Matthew R. Jones, Bill P. Curry, M. Quinn Brewster, Keng H. Leong

Faculty Publications

We invert the Fredholm equation representing the light scattered by a single spherical particle or a distribution of spherical particles to obtain the particle size distribution function and refractive index. We obtain the solution by expanding the distribution function as a linear combination of a set of orthonormal basis functions. The set of orthonormal basis functions is composed of Schmidt-Hilbert eigenfunctions and a set of supplemental basis functions, which have been orthogonalized with respect to the Schmidt-Hilbert eigenfunctions by using the Gram-Schmidt orthogonalization procedure. We use the orthogonality properties of the basis functions and of the eigenvectors of the kernel …

Go to article

Inversion Of Light Scattering Measurements For Particle Size And Optical Constants: Experimental Study, Matthew R. Jones, Keng H. Leong, M. Quinn Brewster, Bill P. Curry Jun 1994

Inversion Of Light Scattering Measurements For Particle Size And Optical Constants: Experimental Study, Matthew R. Jones, Keng H. Leong, M. Quinn Brewster, Bill P. Curry

Faculty Publications

Measurements of the light scattered by a sample contain information regarding the physical properties of the sample. Laser light-scattering measurements can be made unobtrusively in environments that are inaccessible to other types of measurements, so laser light-scattering techniques have become an important tool in aerosol research. The primary difficulty associated with using light-scattering techniques to determine aerosol particle properties is inverting the measurements or extracting the desired information from the measurements. In this study we use a 15-channel polar nephelometer to measure the light-scattering patterns of monodisperse polystyrene spheres. The light-scattering measurements are inverted, and the particle size distribution function …

Go to article

Demonstration Of A Novel 3-D Autostereoscopic Display, M. W. Jones, Gregory P. Nordin, S. T. Kowel, J. H. Kulick, R. G. Lindquist, P. J. Nasiatka Jun 1994

Demonstration Of A Novel 3-D Autostereoscopic Display, M. W. Jones, Gregory P. Nordin, S. T. Kowel, J. H. Kulick, R. G. Lindquist, P. J. Nasiatka

Faculty Publications

We report what we believe is the first static implementation of the partial-pixel architecture, which provides a conceptual framework for the construction of real-time three-dimensional displays that are functionally equivalent to holographic stereograms (i.e., the simultaneous display of a series of stereoscopic images). The device is physically realized as a set of amplitude diffraction gratings on a chrome mask that was fabricated by standard photolithographic techniques. The intended three-dimensional object encoded in the display was strikingly visible on readout with an incoherent illumination source.

Go to article

High Resolution Liquid Crystal Phase Grating Formed By Fringing Fields From Interdigitated Electrodes, Gregory P. Nordin, M. Friends, J. M. Jarem, S. T. Kowel, J. H. Kulick, T. Leslie, R. G. Lindquist May 1994

High Resolution Liquid Crystal Phase Grating Formed By Fringing Fields From Interdigitated Electrodes, Gregory P. Nordin, M. Friends, J. M. Jarem, S. T. Kowel, J. H. Kulick, T. Leslie, R. G. Lindquist

Faculty Publications

We report the formation of thin anisotropic phase gratings in a nematic liquid-crystalline film by use of lateral (fringing) electric fields induced by transparent interdigitated electrodes. These gratings yield high diffraction efficiency (>30%) with a strong dependence on the readout beam incidence angle. In addition, the formation of a defect wall is observed that has a significant effect on the diffraction properties of the phase grating.

Go to article

Preaching From The Book Of Genesis, Mark A. Throntveit Apr 1994

Preaching From The Book Of Genesis, Mark A. Throntveit

Faculty Publications

No abstract provided.

Go to article

Characterization Of Electromagnetically Coupled Superquadric Loop Antennas For Mobile Communications Applications, Michael A. Jensen, Yahya Rahmat-Samii Apr 1994

Characterization Of Electromagnetically Coupled Superquadric Loop Antennas For Mobile Communications Applications, Michael A. Jensen, Yahya Rahmat-Samii

Faculty Publications

Analysis of two mutually coupled loop antennas with arbitrary relative orientation and position and possibly different geometries is presented. The antennas are represented by generalised superquadric curves, which include circular, elliptical, and rectangular loop geometries, and they may be located either in a homogeneous region or next to an infinite ground plane. A Galerkin-type moment method with piecewise sinusoidal subsectional basis and weighting functions is used. Special consideration is given to implement the solution using curved wire segments instead of the commonly employed linear segments to improve computational efficiency. This very general computational tool is used to investigate the behaviour …

Go to article

A Multi-Chip Module Implementation Of A Neural Network, Tony R. Martinez, George L. Rudolph, Linton G. Salmon, Matthew G. Stout Mar 1994

A Multi-Chip Module Implementation Of A Neural Network, Tony R. Martinez, George L. Rudolph, Linton G. Salmon, Matthew G. Stout

Faculty Publications

The requirement for dense interconnect in artificial neural network systems has led researchers to seek high-density interconnect technologies. This paper reports an implementation using multi-chip modules (MCMs) as the interconnect medium. The specific system described is a self-organizing, parallel, and dynamic learning model which requires a dense interconnect technology for effective implementation; this requirement is fulfilled by exploiting MCM technology. The ideas presented in this paper regarding an MCM implementation of artificial neural networks are versatile and can be adapted to apply to other neural network and connectionist models.

Go to article

A Rationale For Coastal Wetland Restoration Through Spoil Bank Management In Louisiana, Usa, R. Eugene Turner, E. M. Swenson, J. M. Lee Mar 1994

A Rationale For Coastal Wetland Restoration Through Spoil Bank Management In Louisiana, Usa, R. Eugene Turner, E. M. Swenson, J. M. Lee

Faculty Publications

The rationale and outline of an implementation plan for restoring coastal wetlands in Louisiana is presented. The rationale for the plan is based on reversing the consequences of documented cause-and-effect relationships between wetland loss and hydrologic change. The main feature is to modify the extensive interlocking network of dredged spoil deposits, or spoil banks, by reestablishing a more natural water flow at moderate flow velocity (/sec). Guidelines for site selection from thousands of potential sites are proposed. Examples of suitable sites are given for intermediate marshes. These sites exhibit rapid deterioration following partial or complete hydrologic impoundment, implying a strong …

Go to article

Vegetation Studies Of The Amazon Basin Using Enhanced Resolution Seasat Scatterometer Data, David G. Long, Perry J. Hardin, Peter T. Whiting Mar 1994

Vegetation Studies Of The Amazon Basin Using Enhanced Resolution Seasat Scatterometer Data, David G. Long, Perry J. Hardin, Peter T. Whiting

Faculty Publications

The Seasat-A scatterometer (SASS) was designed to measure the near-surface wind field over the ocean by inferring the wind from measurements of the surface radar backscatter. While backscatter measurements were also made over land, they have been primarily used for the calibration of the instrument. This has been due in part to the low resolution of the scatterometer measurements (nominally 50 km). In a separate paper the present authors introduced a new method for generating enhanced resolution radar measurements of the Earth's surface using spaceborne scatterometry. In the present paper, the method is used with SASS data to study vegetation …

Go to article

Proof Of Correctness For Asocs Aa3 Networks, J. Cory Barker, Tony R. Martinez Mar 1994

Proof Of Correctness For Asocs Aa3 Networks, J. Cory Barker, Tony R. Martinez

Faculty Publications

This paper analyzes adaptive algorithm 3 (AA3) of adaptive self-organizing concurrent systems (ASOCS) and proves that AA3 correctly fulfills the rules presented. Several different models for ASOCS have been developed. AA3 uses a distributed mechanism for implementing rules so correctness is not obvious. An ASOCS is an adaptive network composed of many simple computing elements operating in parallel. An ASOCS operates in one of two modes: learning and processing. In learning mode, rules are presented to the ASOCS and incorporated in a self-organizing fashion. In processing mode, the ASOCS acts as a parallel hardware circuit that performs the function defined …

Go to article

Capacity Of Automated Highway Systems: Effect Of Platooning And Barriers, H.-S. Jacob Tsao, Randolph Hall, Bruce Hongola Feb 1994

Capacity Of Automated Highway Systems: Effect Of Platooning And Barriers, H.-S. Jacob Tsao, Randolph Hall, Bruce Hongola

Faculty Publications

The concept of Automated Highway Systems (AHS) is based on the belief that an appropriate integration of control and communication technologies placed on the vehicle and on the highway can lead to a large improvement in capacity and safety without requiring a significant amount of additional highway right-of-way. Stemming from this belief are various conceptual scenarios for vehicle/highway automation.An AHS consists of two major components: vehicle/highway automation technology and highway operating strategy. In this paper, we study the capacity of key AHS operating scenarios.

Go to article

Epistemic Decision Theory Applied To Multiple-Target Tracking, Wynn C. Stirling, T. K. Moon, S. E. Budge, J. B. Thompson Feb 1994

Epistemic Decision Theory Applied To Multiple-Target Tracking, Wynn C. Stirling, T. K. Moon, S. E. Budge, J. B. Thompson

Faculty Publications

A decision philosophy that seeks the avoidance of error by trading off belief of truth and value of information is applied to the problem of recognizing tracks from multiple targets (MTT). A successful MTT methodology should be robust in that its performance degrades gracefully as the conditions of the collection become less favorable to optimal operation. By stressing the avoidance, rather than the explicit minimization, of error, the authors obtain a decision rule for trajectory-data association that does not require the resolution of all conflicting hypotheses when the database does not contain sufficient information to do so reliably. This rule, …

Go to article

Electromagnetic Characteristics Of Superquadric Wire Loop Antennas, Michael A. Jensen, Yahya Rahmat-Samii Feb 1994

Electromagnetic Characteristics Of Superquadric Wire Loop Antennas, Michael A. Jensen, Yahya Rahmat-Samii

Faculty Publications

The analysis of antenna configurations in the form of a generalized superquadric loop, which includes circular, elliptical and rectangular loop geometries, is presented in this paper. Use of a Galerkin form of the moment method with piecewise sinusoidal subsectional basis and testing functions provides rapid numerical convergence and accurate representation of the antenna current. A convenient parametric representation for the superquadric curve is developed to allow a subsectional formulation using curved wire segments, rather than the commonly employed piecewise linear segments, to construct the geometry. Both magnetic frill and delta gap source models are implemented to allow a detailed study …

Go to article

A Probabilistic Model For Avcs Longitudinal Collision/Safety Analysis, Jacob Tsao, Randolph Hall Jan 1994

A Probabilistic Model For Avcs Longitudinal Collision/Safety Analysis, Jacob Tsao, Randolph Hall

Faculty Publications

This paper develops a probabilistic model for analyzing longitudinal collision/safety between an abruptly decelerating vehicle and its immediate follower. The input parameters are the length of the gap between the two vehicles, their common speed prior to the failure, the reaction delay of the following vehicle and a bivariate distribution for the two deceleration rates. The output includes the probability of a collision and the probability distribution of the relative speed at collision time We use this model to compare the safety consequences associated with the platooning and “free-agent” longitudinal-separation rules. We also demonstrate that the free-agent rule implemented with …

Go to article

Block Qpsk Modulation Codes With Two Levels Of Error Protection, Robert H. Morelos-Zaragoza, Shu Lin Jan 1994

Block Qpsk Modulation Codes With Two Levels Of Error Protection, Robert H. Morelos-Zaragoza, Shu Lin

Faculty Publications

A class of block QPSK modulation codes for unequal error protection (UEP) is presented. These codes are particularly suitable either for broadcast channels or for communication systems where parts of the information messages are more important than others. An example of the latter is coded speech transmission. Not much is known on the application of block UEP codes in combined coding and modulation schemes. We exhibit a method to combine binary linear UEP (LUEP) block codes of even length, using a Gray mapping, with a QPSK signal set to construct efficient block QPSK modulation codes with nonuniform error protection capabilities …

Go to article

Constraints On Initial Ahs Deployment And The Concept Definition Of A Shuttle Service For Ahs Debut, Jacob Tsao Jan 1994

Constraints On Initial Ahs Deployment And The Concept Definition Of A Shuttle Service For Ahs Debut, Jacob Tsao

Faculty Publications

Highway automation and its evolution involve a multitude of systems issues. Particularly important and difficult in defining a deployment sequence is the very first step, i.e. the first user service involving fully automated freeway driving. However, this importance and the difficulty imply that many factors may severely constrain the initial deployment. After discussing the paramount importance of initial AHS deployment, this paper points out major high-level issues and constraints. Any realistic deployment strategy must take into consideration gradual technology maturation, introduction of new driver role and diminishing conventional driver role for automated driving, high cost of early-generation automation-equipped vehicles, gradual …

Go to article

On A Class Of Optimal Nonbinary Linear Unequal-Error-Protection Codes For Two Sets Of Messages, Robert H. Morelos-Zaragoza, Shu Lin Jan 1994

On A Class Of Optimal Nonbinary Linear Unequal-Error-Protection Codes For Two Sets Of Messages, Robert H. Morelos-Zaragoza, Shu Lin

Faculty Publications

Several authors have addressed the problem of designing good linear unequal error protection (LUEP) codes. However, very little is known about good nonbinary LUEP codes. We present a class of optimal nonbinary LUEP codes for two different sets of messages. By combining t-error-correcting ReedSolomon (RS) codes and shortened nonbinary Hamming codes, we obtain nonbinary LUEP codes that protect one set of messages against any t or fewer symbol errors and the remaining set of messages against any single symbol error. For t ≥ 2, we show that these codes are optimal in the sense of achieving the Hamming lower bound …

Go to article

Characterization Of An Old-Growth Bottomland Hardwood Wetland Forest In Northeast Texas: Harrison Bayou, Laurence C. Walker, Thomas Brantley, Virginia Burkett Jan 1994

Characterization Of An Old-Growth Bottomland Hardwood Wetland Forest In Northeast Texas: Harrison Bayou, Laurence C. Walker, Thomas Brantley, Virginia Burkett

Faculty Publications

Most wetland losses in the southern region over the past 200 years have occurred in bottomland hardwood forests. By 1980 the original extent of palustrine bottomland in Texas had been reduced by 63%, from roughly 16 to 6 million acres. Additional losses have occurred during more recent years as a result of conversion to agriculture and timber harvests; these factors and the need to supply new hardwood chip mills in the region pose a potential threat to the remaining hardwood resource. The Harrison Bayou watershed in northeast Texas contains one of the few relatively undisturbed bottomland hardwood wetland forests in …

Go to article

Basic Concepts In Computer Analysis Of Forestry Investments, Steven H. Bullard, Thomas J. Straka Jan 1994

Basic Concepts In Computer Analysis Of Forestry Investments, Steven H. Bullard, Thomas J. Straka

Faculty Publications

In the last 20 years alone, computer hardware and software developments have dramatically increased our ability to calculate financial criteria quickly and accurately. While these advances have dramatically increased our ability to calculate, they have not replaced the need to understand what is being calculated, or how the results should be interpreted and applied. Our objective in the present article is to provide background information for understandingthe "what" and "how" of computer applications for forestry investment analysis. We briefly discuss the most important financial criteria that are calculated by investment analysis computer programs; we also describe their recommended uses and …

Go to article

First Prev Next Last