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Dementia In Stroke Survivors In The Stroke Data Bank Cohort: Prevalence, Incidence, Risk Factors, And Computed Tomographic Findings, Thomas K. Tatemichi, Mary A. Foulkes, J. P. Mohr, Jeffrey R. Hewitt, Daniel B. Hier, Thomas R. Price, Philip A. Wolf Jan 1990

Dementia In Stroke Survivors In The Stroke Data Bank Cohort: Prevalence, Incidence, Risk Factors, And Computed Tomographic Findings, Thomas K. Tatemichi, Mary A. Foulkes, J. P. Mohr, Jeffrey R. Hewitt, Daniel B. Hier, Thomas R. Price, Philip A. Wolf

Chemistry Faculty Research & Creative Works

We Determined the Prevalence of Dementia in 927 Patients with Acute Ischemic Stroke Aged ≥60 Years in the Stroke Data Bank Cohort based on the Examining Neurologist's Best Judgment Diagnostic Agreement among Examiners Was 68% (K=0.34). of 726 Testable Patients, 116 (16%) Were Demented. Prevalence of Dementia Was Related to Age But Not to Sex, Race, Handedness, Educational Level, or Employment Status Before the Stroke. Previous Stroke and Previous Myocardial Infarction Were Related to Prevalence of Dementia Although Hypertension, Diabetes Mellitus, Atrial Fibrillation, and Previous Use of Antithrombotic Drugs Were Not Prevalence of Dementia Was Most Frequent in Patients with …

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Knowledge-Based Prototype For Improving Scheduling Productivity, Colin Othniel Benjamin, Daniel L. Babcock, N. B. Yunus, John B. Kincaid Jan 1990

Knowledge-Based Prototype For Improving Scheduling Productivity, Colin Othniel Benjamin, Daniel L. Babcock, N. B. Yunus, John B. Kincaid

Engineering Management and Systems Engineering Faculty Research & Creative Works

The development of efficient construction plans and schedules presents continuing challenges to construction schedulers. Knowledge-based systems offer considerable potential as computer-based planning tools to aid the development of realistic project plans and schedules. This paper outlines the development of a knowledge-based prototype system for construction planning and scheduling and evaluates its effectiveness as a tool for improving the productivity of inexperienced construction project schedulers. The prototype, developed using the M.1 knowledge engineering shell, incorporates data bases, algorithm, and heuristics that mimic the decision process of expert construction project schedulers and identifies a work breakdown structure and precedence relationships. Inexperienced schedulers …

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A Parallel Architecture For Stock Cutting Problem, Cihan H. Dagli, Alireza Hajakbari Jan 1990

A Parallel Architecture For Stock Cutting Problem, Cihan H. Dagli, Alireza Hajakbari

Engineering Management and Systems Engineering Faculty Research & Creative Works

The problem of allocating irregular patterns arises frequently in applications where it has to be determined how a set of two-dimensional shapes will fit onto a stock sheet of finite dimensions with minimum waste. The use of the simulated annealing approach for the solution of this problem is described

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Cost Justification Of An Expert System, Alice E. Smith, Cihan H. Dagli Jan 1990

Cost Justification Of An Expert System, Alice E. Smith, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

It is pointed out that, like other projects which spend corporate dollars, an expert system must be analyzed for its economic and strategic worth to the organization. Both traditional engineering economy project analysis and multivariate holistic methods can be applicable. The fundamental strategy of the analyst is to decide upon the evaluation methodologies, gather cost and benefit data, study the project from various perspectives, and present the results and recommendations.

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Simulated Annealing Approach For Solving Stock Cutting Problem, Cihan H. Dagli, Alireza Hajakbari Jan 1990

Simulated Annealing Approach For Solving Stock Cutting Problem, Cihan H. Dagli, Alireza Hajakbari

Engineering Management and Systems Engineering Faculty Research & Creative Works

The simulated annealing approach is applied to stock cutting. The conceptual approach proposed uses an energy function that measures the area of the rectangular enclosure of all the patterns to be nested, the level of similarity between pattern pairs, and the amount of overlap among patterns in evaluating various pattern configurations to be generated by the simulated annealing algorithm. Three methods for pattern configuration generation are considered. The first method uses heuristics to generate the initial configuration. The second and third methods use random selection and random placement of patterns

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Enhanced Radiative Auger Emission From Lithiumlike S13+16, E. M. Bernstein, M. W. Clark, C. S. Oglesby, J. A. Tanis, W. G. Graham, Robert H. Mcfarland, T. J. Morgan, B. M. Johnson, K. W. Jones Jan 1990

Enhanced Radiative Auger Emission From Lithiumlike S13+16, E. M. Bernstein, M. W. Clark, C. S. Oglesby, J. A. Tanis, W. G. Graham, Robert H. Mcfarland, T. J. Morgan, B. M. Johnson, K. W. Jones

Physics Faculty Research & Creative Works

The radiative Auger emission (RAE) from 0.946.25-MeV/u 16S13+ (lithiumlike) projectiles excited in collisions with He target atoms has been measured. For these highly stripped ions the intensity of RAE photons relative to K x-ray emission is enhanced by about a factor of five compared with theoretical calculations and an earlier experimental measurement for S ions with few electron vacancies. The enhancement of RAE for S13+ is qualitatively similar to results reported previously for lithiumlike 23V20+; however, some differences between S and V are evident. © 1990 The American Physical Society.

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Subshell Electron Capture In Collisions Of Fully Stripped Ions With He And H2 At Intermediate Energies, L. Meng, C. O. Reinhold, Ronald E. Olson Jan 1990

Subshell Electron Capture In Collisions Of Fully Stripped Ions With He And H2 At Intermediate Energies, L. Meng, C. O. Reinhold, Ronald E. Olson

Physics Faculty Research & Creative Works

Classical phase-space models of the hydrogen molecule and helium are utilized to study shell and subshell electron-capture processes in collisions of fully stripped ions on charge states from 1 to 15 with H2 and He at intermediate impact energies (20200 keV/amu). Autoionization after double electron capture is approximated and is found to be an important channel for high projectile charges. The resulting (n,l) distributions for proton impact of He and H2 as well as total capture cross sections are found to be in very good agreement with experimental data. l distributions for high projectile charges are also analyzed for …

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A Review Of Recent Advances In Economic Dispatch, Badrul H. Chowdhury, S. Rahman Jan 1990

A Review Of Recent Advances In Economic Dispatch, Badrul H. Chowdhury, S. Rahman

Electrical and Computer Engineering Faculty Research & Creative Works

A survey is presented of papers and reports that address various aspects of economic dispatch. The time period considered is 1977-88. Four related areas of economic dispatch are identified and papers published in the general areas of economic dispatch are classified into these. These areas are: optimal power flow, economic dispatch in relation to AGC, dynamic dispatch, and economic dispatch with nonconventional generation sources.

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Increased Separation By Variable-Temperature Stepwise Desorption In Multicomponent Adsorption Processes, Suvit Kulvaranon, Marshall E. Findley, Athanasios I. Liapis Jan 1990

Increased Separation By Variable-Temperature Stepwise Desorption In Multicomponent Adsorption Processes, Suvit Kulvaranon, Marshall E. Findley, Athanasios I. Liapis

Chemical and Biochemical Engineering Faculty Research & Creative Works

When more components than desired are adsorbed, adsorption-desorption separation processes may not be satisfactory. However, in the cases of ethanol and water adsorption on activated carbon, propane and propylene adsorption on molecular sieves, and hydrogen sulfide, carbon dioxide, and propane adsorption on molecular sieves, it has been found that a variable-temperature stepwise desorption (VTSD) procedure following the adsorption stage can significantly increase the degree of separation achieved compared to a complete desorption of all adsorbed components. Studies indicate that these increased separations are in part due to nonequilibrium effects. An estimation of economic factors in separating low concentration propylene in …

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Robust Nonlinear Control Of Brushless Dc Motors For Direct-Drive Robotic Applications, N. Hemati, J. S. Thorp, Ming-Chuan Leu Jan 1990

Robust Nonlinear Control Of Brushless Dc Motors For Direct-Drive Robotic Applications, N. Hemati, J. S. Thorp, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The control problem associated with brushless DC motors (BLDCMs) for direct-drive robotic applications is considered. In order to guarantee the high-performance operation of BLDCMs in such applications, the effects of reluctance variations and magnetic saturation are accounted for in the model. Such a BLDCM model constitutes a highly coupled and nonlinear dynamic system. Using the transformation theory of nonlinear systems, a feedback control law, which is shown to compensate for the system nonlinearities, is derived. Conditions under which such a control law is possible are presented. The need for the derivation of explicit commutation strategies is eliminated, resulting in reduction …

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A Differential Equation Approach To Swept Volumes, Ming-Chuan Leu, Denis Blackmore Jan 1990

A Differential Equation Approach To Swept Volumes, Ming-Chuan Leu, Denis Blackmore

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An approach to the analysis of swept volumes is introduced. It is shown that every smooth Euclidean motion or sweep, can be identified with a first-order, linear, ordinary differential equation. This sweep differential equation provides useful insights into the topological and geometrical nature of the swept volume of an object. A certain class, autonomous sweeps, is identified by the form of the associated differential equation, and several properties of the swept volumes of the members of this class are analyzed. The results are applied to generate swept volumes for a number of objects. Implementation of the sweep differential equation approach …

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Planning Optimal Robot Trajectories By Cell Mapping, W. H. Zhu, Ming-Chuan Leu Jan 1990

Planning Optimal Robot Trajectories By Cell Mapping, W. H. Zhu, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A cell-mapping method is introduced for planning global trajectories of robotic manipulators in cases where the cell space is composed of combination pairs of plane cells. With the proposed method, optimal trajectory problems in the free field and in the obstacle-constrained field are studied. Two numerical examples are given to show the obtained optimal trajectories and controls.

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A Two-Dimensional Analog Vlsi Circuit For Detecting Discontinuities In Early Vision, John G. Harris, Christof Koch, Jin Luo Jan 1990

A Two-Dimensional Analog Vlsi Circuit For Detecting Discontinuities In Early Vision, John G. Harris, Christof Koch, Jin Luo

Electrical and Computer Engineering Faculty Research & Creative Works

A large number of computer vision algorithms for finding intensity edges, computing motion, depth, and color, and recovering the three-dimensional shape of objects have been developed within the framework of minimizing an associated "energy" or "cost" functional. Particularly successful has been the introduction of binary variables coding for discontinuities in intensity, optical flow field, depth, and other variables, allowing image segmentation to occur in these modalities. The associated nonconvex variational functionals can be mapped onto analog, resistive networks, such that the stationary voltage distribution in the network corresponds to a minimum of the functional. The performance of an experimental analog …

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Thermoelastic Problem Of A Thick Orthotopic Beam On Twodirectiooal Elastic Foundation, Victor Birman Jan 1990

Thermoelastic Problem Of A Thick Orthotopic Beam On Twodirectiooal Elastic Foundation, Victor Birman

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The thermoelastic problem of an orthotropic beam supported by an elastic foundation which resists lateral deformations as well as displacements parallel to the beam axis is considered. The solution for a relatively thick beam is obtained based on the first-order shear deformation theory. The problem is reduced to- the solution of an ordinary seventh-order differential equation which can be obtained in the closed form. The case of a slender beam is treated as a particular case of a more general solution for a shear deformable beam. © 1990 ASME.

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Boundary Element-Image Method Approach To Seismic Modeling, Richard E. Dubroff Jan 1990

Boundary Element-Image Method Approach To Seismic Modeling, Richard E. Dubroff

Electrical and Computer Engineering Faculty Research & Creative Works

The Boundary Element-Image Method is Proposed as a Method for Generating Synthetic Seismograms in a System of Piecewise Homogeneous Layers. the Present Approach Uses the Boundary Conditions Explicitly in Order to Develop a System of Integral Equations. Although This Method Can Be Formulated in a General Way, Specific Computational Advantages Occur When the Basis and Testing Functions Are Chosen as Harmonically Related Complex Sinusoids. -From Authors

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A Study Of The Hydration Properties Of Selected Laser Dye Aerosols Including Continuous-Flow Parallel Plate And Alternating-Gradient Thermal Diffusion Cloud Chamber Measurements In The High Supersaturation Regime, Donald E. Hagen, Max B. Trueblood, Darryl J. Alofs Jan 1990

A Study Of The Hydration Properties Of Selected Laser Dye Aerosols Including Continuous-Flow Parallel Plate And Alternating-Gradient Thermal Diffusion Cloud Chamber Measurements In The High Supersaturation Regime, Donald E. Hagen, Max B. Trueblood, Darryl J. Alofs

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The Hydration Behavior of Aerosols made Up of Various Fluorescent Dyes when Exposed to Water Saturation or Supersaturated Conditions Has Been Studied. Critical Supersaturation Spectra Are Reported. the Dyes Are Found to Behave as High Molecular Weight Ionic Compounds that Obey Kohler Theory. their Relevant Kohler Parameters Are Measured. This Study Makes Use of and Compares Results from the Isothermal Hazecontinuous-Flowand Alternating-Gradient Thermal Diffusion Cloud Chambers. the Ability of the Continuous-Flow Thermal Diffusion Chamber to Operate Correctly at High Supersaturations is Shown. © 1990 Elsevier Science Publishing Co., Inc.

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Oxidation-Reduction Behavior Of Undoped And Sr-Doped Lamno3: Defect Structure, Electrical Conductivity, And Thermoelectric Power, J. H. Kuo, Harlan U. Anderson, Don M. Sparlin Jan 1990

Oxidation-Reduction Behavior Of Undoped And Sr-Doped Lamno3: Defect Structure, Electrical Conductivity, And Thermoelectric Power, J. H. Kuo, Harlan U. Anderson, Don M. Sparlin

Materials Science and Engineering Faculty Research & Creative Works

Seebeck coefficient and electrical conductivity measurements were performed for undoped and Sr-doped LaMnO3 as a function of temperature and oxygen partial pressure. The results of electrical conductivity showed typical p-type behavior. As reduction proceeded, the electrical conductivity of these LaMnO3-based perovskites decreased with P 1 4O2. The analysis of the electrical conductivity data was performed by extending the defect model from a previous thermogravimetric (TG) study. The measured Seebeck coefficients were found to be positive except for the most reducing conditions when the decomposition into multiple phases occurred. The Heikes formula was adopted to interpret …

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State-Selective Capture In Collisions Between Ions And Ground- And Excited-State Alkali-Metal Atoms, J. Pascale, Ronald E. Olson, C. O. Reinhold Jan 1990

State-Selective Capture In Collisions Between Ions And Ground- And Excited-State Alkali-Metal Atoms, J. Pascale, Ronald E. Olson, C. O. Reinhold

Physics Faculty Research & Creative Works

Total cross sections for state-selective electron capture in collisions between ions and alkali-metal atoms have been calculated by means of a three-body classical-trajectory Monte Carlo (CTMC) method using model potentials to describe the electron ionic-core interactions. Calculations have been performed for Na+-Na(28d) collisions and for N5+ and Ar8+-Cs(6s) collisions. The collision velocity range corresponds to 0.5vp/ve2, where vp is the projectile velocity in the laboratory frame and ve is the initial orbital velocity of the electron bound to the alkali-metal core. In the case of Na++Na(28d) collisions, calculations of the final n,l,m distributions …

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Experimental And Theoretical Study Of The Electron Spectra In 66.7350-Kev/U C++He Collisions, L. H. Toburen, R. (Robert) D. Dubois, C. O. Reinhold, D. R. Schultz, Ronald E. Olson Jan 1990

Experimental And Theoretical Study Of The Electron Spectra In 66.7350-Kev/U C++He Collisions, L. H. Toburen, R. (Robert) D. Dubois, C. O. Reinhold, D. R. Schultz, Ronald E. Olson

Physics Faculty Research & Creative Works

Measurements of the differential and total cross sections for production of free electrons are reported for collisions of 66.7350-keV/u C+ ions with He. The experimental data are compared with theoretical calculations that include electron emission from both target and projectile using the classical-trajectory Monte Carlo method and the independent-electron approximation. Good agreement is observed between theory and experiment, and structures appearing in the electron spectra can be explained in terms of either, or both, target and projectile ionization. © 1990 The American Physical Society.

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Binary Nucleation Of Ethanol And Water, John L. Schmitt, J. Whitten, G. W. Adams, R. A. Zalabsky Jan 1990

Binary Nucleation Of Ethanol And Water, John L. Schmitt, J. Whitten, G. W. Adams, R. A. Zalabsky

Physics Faculty Research & Creative Works

The authors have used a fast expansion cloud chamber to measure binary homogeneous nucleation rates in several ethanol-water mixtures as a function of temperature, ethanol and water activities and nucleation rate. Data (ethanol and water activities) are presented for a range in nucleation rate from 10 3 to 105 drops/cm3 s from 263 to 293 K for mixtures having mole ratios (ethanol/water) of 10, 4, 0.1, 0.01, and 0.001. A comparison of the extensive data set to other data in the literature shows good agreement. We find current theory, as expected, is unable to accurately predict the data at low …

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A Balancing Method For Reduced Order Modelling Of Unstable Systems, Rajiva Prakash, Vittal S. Rao Jan 1990

A Balancing Method For Reduced Order Modelling Of Unstable Systems, Rajiva Prakash, Vittal S. Rao

Electrical and Computer Engineering Faculty Research & Creative Works

Moore's balancing method of model reduction has many attractive properties and is used widely in practice. However, this method suffers from the drawback that it is not applicable for unstable systems. This paper introduces a balancing method of model reduction to overcome this problem. The proposed technique obtains the reduced order model by balancing and truncating frequency domain controllability and observability Gramians. Analytical treatment is given for associated properties of the Gramians, and the balancing and truncation steps of model reduction. A numerical example is used to demonstrate the new approach. © 1990.

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Fixed Mode Elimination In Decentralized Control Systems Using Eigenvalue Sensitivities, Jorge R.B. Souza, Vittal S. Rao Jan 1990

Fixed Mode Elimination In Decentralized Control Systems Using Eigenvalue Sensitivities, Jorge R.B. Souza, Vittal S. Rao

Electrical and Computer Engineering Faculty Research & Creative Works

The knowledge of fixed modes plays an important role in the design of decentralized controllers for large scale systems. An approach based on a parametric sensitivity of eigenvalues is proposed to select the information to be exchanged between control stations in order to eliminate decentralized fixed modes. The procedure is illustrated with an example. © 1990.

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Growth Of Cdte And Cds/Cdte Heterojunctions On Metal Substrates By Spray Pyrolysis, Alok K. Berry, Jack L. Boone, Thomas P. Van Doren Jan 1990

Growth Of Cdte And Cds/Cdte Heterojunctions On Metal Substrates By Spray Pyrolysis, Alok K. Berry, Jack L. Boone, Thomas P. Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

Preliminary results of the spray pyrolysis of thin films of CdTe on metal substrates are reported. The films are hard and adhere well to the substrate. A n-CdS/p-CdTe rectifying junction is also grown completely by spray pyrolysis on the metallic substrate. The ability to produce p-n junctions using the inexpensive and simple procedure of spray pyrolysis may lead to a viable process for mass production of solar cells. © 1990.

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Bundled Cable Parameters And Their Impact On Emi Measurement Repeatability, Todd H. Hubing Jan 1990

Bundled Cable Parameters And Their Impact On Emi Measurement Repeatability, Todd H. Hubing

Electrical and Computer Engineering Faculty Research & Creative Works

EMI (electromagnetic interference) test procedures specify that long cables should be bundled at their center in some circumstances. The author investigates the effect of cable bundling using analytical models and measurements. He examines how cable bundle parameters such as length and "tightness'' can affect the repeatability of the measurement. Simple models of a bundled cable suggest that relatively small changes in the geometry of the bundle can significantly affect the common-mode cable current. Parameters such as length, tightness, location and the number of turns determine the impedance of the bundle. As the impedance of the cable bundle changes, the resonant …

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An Expert System To Convert Knowledge-Based Geological Engineering Systems Into Fortran, Ralph W. Wilkerson, Jill J. Cress Jan 1990

An Expert System To Convert Knowledge-Based Geological Engineering Systems Into Fortran, Ralph W. Wilkerson, Jill J. Cress

Computer Science Faculty Research & Creative Works

A knowledge-based geographic information system (KBGIS) for geological engineering map (GEM) production was developed in GoldWorks, an expert system development shell. Using this shell, the geological engineer is able to develop a rule base for a particular application that results in a valid GEM. However, this implementation failed as a practical production system due to the excessive execution time required to produce a GEM. To solve this problem, a conversion expert system was developed which accepted, as input, a KBGIS and produced, as output, the equivalent Fortran code. Two major objectives are accomplished as a result of this system: GEN …

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Experimentation With Large-Grained Parallelism Using Local Area Networks, Ralph W. Wilkerson, Douglas E. Meyer Jan 1990

Experimentation With Large-Grained Parallelism Using Local Area Networks, Ralph W. Wilkerson, Douglas E. Meyer

Computer Science Faculty Research & Creative Works

HIGHLAND, a distributed-memory parallel processing environment for heterogeneous local area networks, has been developed. Designed as both a teaching and a research tool, its purpose is to provide an effective mechanism by which a number of networked UNIX workstations, dissimilar in both vendor and performance, can be directly manipulated as a single, unified, multiprocessing system. Utilizing the MIT X-windows environment, HIGHLAND supports a highly interactive graphical interface through which a programmer can create, modify, and control complex systems of communicating processes

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Highland: A Graph-Based Parallel Processing Environment For Heterogeneous Local Area Networks, Ralph W. Wilkerson, Douglas E. Meyer Jan 1990

Highland: A Graph-Based Parallel Processing Environment For Heterogeneous Local Area Networks, Ralph W. Wilkerson, Douglas E. Meyer

Computer Science Faculty Research & Creative Works

No abstract provided.

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Role Of Term Symmetry In E-Completion Procedures, Ralph W. Wilkerson, Blayne E. Mayfield Jan 1990

Role Of Term Symmetry In E-Completion Procedures, Ralph W. Wilkerson, Blayne E. Mayfield

Computer Science Faculty Research & Creative Works

No abstract provided.

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Experimental Comparison Of Bidding And Drafting Load Sharing Protocols, Andrew Ross, Bruce M. Mcmillin Jan 1990

Experimental Comparison Of Bidding And Drafting Load Sharing Protocols, Andrew Ross, Bruce M. Mcmillin

Computer Science Faculty Research & Creative Works

In recent years, a dramatic rise in the number of personal workstations interconnected via local area networks has occurred in the workplace. These can be organized as distributed computing systems. The combined computing power of these systems are often greater than mainframes of a decade ago, and usually less expensive. There is a growing interest in harnessing this often-underutilized power. Researchers are focusing their attention on remote execution of processes as one solution. An additional topic of research is to balance a workload among a series of computers. Remote execution is made possible because the distributed operating system provides migration …

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Computational Intelligence In Cad/Cam Applications, Chaman Sabharwal, Thomas G. Melson, Martin D. Fraser Jan 1990

Computational Intelligence In Cad/Cam Applications, Chaman Sabharwal, Thomas G. Melson, Martin D. Fraser

Computer Science Faculty Research & Creative Works

This paper presents a fundamental, direct, and powerful approach to the surface/surface intersection problem in CAD/CAM applications. The algorithm is designed and implemented in three steps: a) Preprocessing- locate the potentially intersecting sections of the surfaces and decompose the surfaces into surface elements within specified flatness tolerance; b) Intersection- decompose the possibly intersecting pairs of surface elements into continuous surface triangulations to find the approximate intersections between the pairs of surface elements; c) Postprocessing-assemble the intersection primitives into curves of intersection, refine the accuracy of computed intersection points, and compact the intersection curves. This surface/surface intersection algorithm is applicable to …

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