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1993

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Articles 31 - 60 of 428

Full-Text Articles in Computer Sciences

Multiple Model Adaptive Estimation Applied To The Lambda Urv For Failure Detection And Identification, David W. Lane Dec 1993

Multiple Model Adaptive Estimation Applied To The Lambda Urv For Failure Detection And Identification, David W. Lane

Theses and Dissertations

Multiple Model Adaptive Estimation (MMAE) is a method of estimating unknown system parameters by modeling all possible parameter configurations in several models. The parameters for this research are failure status conditions associated with flight control actuators and sensors on the LAMBDA Unmanned Research Vehicle, an experimental aircraft operated by Wright Laboratory Flight Controls Division at Wright-Patterson Air Force Base, Ohio. Six actuator failures and eight sensor failures are modeled, along with the fully functional aircraft, in fifteen elemental Kalman filters. These filters propagate and update their own aircraft state estimates in real time. A probability computation representing the likelihood of …

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Failure Mechanisms Of High Temperature Semiconductor Lasers, David H. Leicester Dec 1993

Failure Mechanisms Of High Temperature Semiconductor Lasers, David H. Leicester

Theses and Dissertations

The primary intent of this research was to determine the influence of three common degradation mechanisms, dark area defects, facet degradation, and contact degradation, on the operational lifetime of GaAs edge-emitting semiconductor lasers driven by continuous current at 100 deg C. Inherent to this work was the quantified characterization of the lasers during their operation. This characterization arose as the power output as a function of driving current at room temperature before and after laser exposure to 100 deg C ambient temperature. These power vs. current characterizations were conducted at room temperature on each laser before and after exposure to …

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Evaluation Of An Acoustic Charge Transport (Act) Device For Adaptive Interference Suppression In Spread Spectrum Communications Systems, Michael S. Mills Dec 1993

Evaluation Of An Acoustic Charge Transport (Act) Device For Adaptive Interference Suppression In Spread Spectrum Communications Systems, Michael S. Mills

Theses and Dissertations

Analytical results have shown that adaptive filtering can be a powerful tool for the rejection of narrowband interference in a direct sequence spread spectrum receiver. However, the complexity of adaptive filtering hardware has hindered the experimental validation of these results. This thesis describes a unique adaptive filter architecture for implementing the Widrow-Hoff Least- Mean-Square (LMS) algorithm using two state-of-the-art Acoustic Charge Transport (ACT) Programmable Transversal Filters (PTFs). Signal-to-noise ratio improvement measurements demonstrate the effectiveness of the adaptive filter for suppressing single- and dual-tone jammers at jammer-to-signal ratios (JSRs) of up to 30 dB. It is shown that the ACT adaptive …

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Failure Detection, Isolation, And Recovery In An Integrated Navigation System, William B. Mosle Iii Dec 1993

Failure Detection, Isolation, And Recovery In An Integrated Navigation System, William B. Mosle Iii

Theses and Dissertations

An Inertial Navigation System (INS), the Global Positioning System (GPS), and a ground based transponder system (RRS) can all be used to provide the user with a navigation solution. Yet by integrating these three navigation systems with an extended Kalman filter (EKF), a navigation solution is attained that benefits from the information of all three subsystems. This research develops a multiple model EKF failure detection, isolation, and recovery (FDIR) algorithm using a Chi-Square failure test to provide robust navigation solution to measurement failures. The algorithm specifically counters failures in the GPS and RRS range measurements. Analysis is conducted using a …

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The Afit Multielectrode Array For Neural Recording And Simulation: Design, Testing, And Encapsulation, James R. Reid Jr Dec 1993

The Afit Multielectrode Array For Neural Recording And Simulation: Design, Testing, And Encapsulation, James R. Reid Jr

Theses and Dissertations

A two-dimensional, X-Y addressable, multiplexed array of 256 electrodes (16 x 16) has been fabricated using conventional semiconductor processing techniques. The individual electrodes are 16O microns x 160 microns, approximating the size of the cortical columns; the overall array size is 3910 microns x 3910 microns. The array has been fitted to a chronically implantable package and tested for several days in a simulated neural environment. EEG-like data were collected successfully from individual electrodes in the array. This array improves on a previous design of a 16 electrode (4 x 4) array that was chronically implanted on the cortex of …

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Development Of Computer Software To Aid Environmental Decision Makers In The Education And Training Of Air Force Remedial Project Managers, Roger R. Ouellette, Bruce K. Lyman Dec 1993

Development Of Computer Software To Aid Environmental Decision Makers In The Education And Training Of Air Force Remedial Project Managers, Roger R. Ouellette, Bruce K. Lyman

Theses and Dissertations

By the end of Fiscal Year 1991, the Air Force had identified 4,354 contaminated sites. Much like the 177 toxic sites at McClellan AFB, bases across the country and throughput the world are filled with chrome, lead, paint solvents and many other toxics that are rendering water supplies unusable and endangering the health of millions of people living in and around these bases. Air Force officials continue to identify contaminated sites with no end in sight. Since the cleanup of these toxic materials involves diverse, complex activities, the Air Force created the duty position of Remedial Project Manager to manage …

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Filtering, Coding, And Compression With Malvar Wavelets, Stephen R. Hall Dec 1993

Filtering, Coding, And Compression With Malvar Wavelets, Stephen R. Hall

Theses and Dissertations

This thesis develops and evaluates a number of new concepts and tools for the analysis of signals using Malvar wavelets lapped orthogonal transforms . Windowing, often employed as a spectral estimation technique, can result in irreparable distortions in the transformed signal. By utilizing the Malvar wavelet, any signal distortion resulting from the transformation can be eliminated or cancelled during reconstruction. This is accomplished by placing conditions on the window and the basis function and then incorporating the window into the orthonormal representation. Paradigms for both a complex-valued and a real-valued Malvar wavelet are summarized. I-lie algorithms for the wavelets were …

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Solving The Ranking And Selection Indifference-Zone Formulation For Normal Distributions Using Computer Software, Catherine A. Poston Dec 1993

Solving The Ranking And Selection Indifference-Zone Formulation For Normal Distributions Using Computer Software, Catherine A. Poston

Theses and Dissertations

Ranking and selection procedures are statistical methods used to compare and choose the best among a group of similar statistically distributed populations. The two predominant approaches to solving ranking and selection problems are Guptas subset selection formulation and Bechhofers indifference- zone formulation. For the indifference-zone formulation where the populations have equal sample sizes, Barr and Rizvi developed an integral expression of the probability of correct selection PCS. Given appropriate parameters, the integral expression can be solved to determine the common sample size required to attain a desired PCS. Tables with selected solutions to the integral expression are available for a …

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An Analysis Of The Root Causes Of Delays And Deficiencies In The Development Of Embedded Software For Air Force Weapon Systems, Jay R. Hopkins, Curtis De Keyrel Dec 1993

An Analysis Of The Root Causes Of Delays And Deficiencies In The Development Of Embedded Software For Air Force Weapon Systems, Jay R. Hopkins, Curtis De Keyrel

Theses and Dissertations

The importance of embedded software, used in every subsystem of ah major weapon systems used by the United States Air Force, has increased drastically over the last decades. However, in spite of the regulations currently in existence, developing and acquiring software which meets the user requirements within the original cost and schedule estimates continues to be difficult. At the same time, the Air Force has pushed to improve the development process with the Total Quality Management TQM program. The primary method used to improve the process has been to create metrics, collect data on these metrics, and then perform a …

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Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 9, Number 10, December 1993, College Of Engineering And Computer Science, Wright State University Dec 1993

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 9, Number 10, December 1993, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A ten page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

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Parallel H-V Drawings Of Binary Trees, Panagiotis T. Metaxas, Grammati E. Pantziou, Antonis Symvonis Dec 1993

Parallel H-V Drawings Of Binary Trees, Panagiotis T. Metaxas, Grammati E. Pantziou, Antonis Symvonis

Computer Science Technical Reports

In this paper we present a method to obtain optimal h-v and inclusion drawings in parallel. Based on parallel tree contraction, our method computes optimal (with respect to a class of cost functions of the enclosing rectangle) drawings in $O(\log^2 n)$ parallel time by using a polynomial number of EREW processors. The number of processors reduces substantially when we study minimum area drawings. The method can be extended to compute optimal inclusion layouts in the case where each leaf $l$ of the tree is represented by rectangle $l_x \times l_y$ (the dimensions of which are part of the input). For …

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Probing Tcp Implementations, Douglas E. Comer, John C. Lin Dec 1993

Probing Tcp Implementations, Douglas E. Comer, John C. Lin

Department of Computer Science Technical Reports

No abstract provided.

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An Optimal O(Log Log N) Time Parallel Algorithm For Detecting All Squares In A String, Albert Apostolico, Dany Breslauer Dec 1993

An Optimal O(Log Log N) Time Parallel Algorithm For Detecting All Squares In A String, Albert Apostolico, Dany Breslauer

Department of Computer Science Technical Reports

No abstract provided.

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C3: A Parallel Model For Coarse-Grained Machines, Susanne E. Hambrusch, Ashfaq A. Khokhar Dec 1993

C3: A Parallel Model For Coarse-Grained Machines, Susanne E. Hambrusch, Ashfaq A. Khokhar

Department of Computer Science Technical Reports

No abstract provided.

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A Generalized Schwarz Splitting Method Based On Hermite Collocation For Elliptic Boundary Value Problems, Yu-Ling Lai, Apostolos Hadjidimos, Elias N. Houstis Dec 1993

A Generalized Schwarz Splitting Method Based On Hermite Collocation For Elliptic Boundary Value Problems, Yu-Ling Lai, Apostolos Hadjidimos, Elias N. Houstis

Department of Computer Science Technical Reports

No abstract provided.

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Correctness Proof Of A Geometric Constraint Solver, Ioannis Fudos, Christoph M. Hoffmann Dec 1993

Correctness Proof Of A Geometric Constraint Solver, Ioannis Fudos, Christoph M. Hoffmann

Department of Computer Science Technical Reports

No abstract provided.

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Combinatorial Optimization Problems For Which Almost Every Algorithm Is Asymptotically Optimal, Wojciech Szpankowski Dec 1993

Combinatorial Optimization Problems For Which Almost Every Algorithm Is Asymptotically Optimal, Wojciech Szpankowski

Department of Computer Science Technical Reports

No abstract provided.

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Constructing Distributed Schedulers Using The Messiahs Interface Language, Steve J. Chapin, Eugene H. Spafford Dec 1993

Constructing Distributed Schedulers Using The Messiahs Interface Language, Steve J. Chapin, Eugene H. Spafford

Department of Computer Science Technical Reports

No abstract provided.

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Parallel Numerical Methods For Partial Differential Equations (Ph.D. Thesis), Sang-Bae Kim Dec 1993

Parallel Numerical Methods For Partial Differential Equations (Ph.D. Thesis), Sang-Bae Kim

Department of Computer Science Technical Reports

No abstract provided.

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A Probabilistic Analysis Of A String Editing Problem And Its Variations, Guy Louchard, Wojciech Szpankowski Dec 1993

A Probabilistic Analysis Of A String Editing Problem And Its Variations, Guy Louchard, Wojciech Szpankowski

Department of Computer Science Technical Reports

No abstract provided.

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Data Structures And Algorithms For The String Statistics Problem, Alberto Apostolico, Franco P. Preparata Dec 1993

Data Structures And Algorithms For The String Statistics Problem, Alberto Apostolico, Franco P. Preparata

Department of Computer Science Technical Reports

No abstract provided.

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A Scheduling Policy With Maximal Stability Region For Rings Networks With Spatial Reuse, Leonidas Georgiadis, Wojciech Szpankowski, Leondros Tassiulas Dec 1993

A Scheduling Policy With Maximal Stability Region For Rings Networks With Spatial Reuse, Leonidas Georgiadis, Wojciech Szpankowski, Leondros Tassiulas

Department of Computer Science Technical Reports

No abstract provided.

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Parallel Dynamic Mesh Generation And Domain Decomposition, Poting Wu, Elias N. Houstis Dec 1993

Parallel Dynamic Mesh Generation And Domain Decomposition, Poting Wu, Elias N. Houstis

Department of Computer Science Technical Reports

No abstract provided.

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Extending Multidatabase Transaction Management Techniques To Software Development Environments, Aidong Zhang, Omran Bukhres Dec 1993

Extending Multidatabase Transaction Management Techniques To Software Development Environments, Aidong Zhang, Omran Bukhres

Department of Computer Science Technical Reports

No abstract provided.

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Collaborative Multimedia Game Environments, Vinod Anupam, Chandrajit L. Bajaj Dec 1993

Collaborative Multimedia Game Environments, Vinod Anupam, Chandrajit L. Bajaj

Department of Computer Science Technical Reports

No abstract provided.

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The Use Of Neural Networks To Support "Intelligent" Scientific Computing, Anupam Joshi, Csanjiva Weerawarana, Elias N. Houstis Dec 1993

The Use Of Neural Networks To Support "Intelligent" Scientific Computing, Anupam Joshi, Csanjiva Weerawarana, Elias N. Houstis

Department of Computer Science Technical Reports

No abstract provided.

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Object-Orientation In Multidatabase Systems, Evaggelia Pitoura, Omran Bukhres, Ahmed K. Elmagarmid Dec 1993

Object-Orientation In Multidatabase Systems, Evaggelia Pitoura, Omran Bukhres, Ahmed K. Elmagarmid

Department of Computer Science Technical Reports

No abstract provided.

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Scheduling Support Mechanisms For Autonomous, Heterogeneous, Distributed Systems (Ph.D. Thesis), Steve J. Chapin Dec 1993

Scheduling Support Mechanisms For Autonomous, Heterogeneous, Distributed Systems (Ph.D. Thesis), Steve J. Chapin

Department of Computer Science Technical Reports

No abstract provided.

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A View-Based Approach To Relaxing Global Serializability In Multidatabase Systems, Aidong Zhang, Evaggelia Pitoura, Bharat K. Bhargava Dec 1993

A View-Based Approach To Relaxing Global Serializability In Multidatabase Systems, Aidong Zhang, Evaggelia Pitoura, Bharat K. Bhargava

Department of Computer Science Technical Reports

No abstract provided.

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Asymptotic Behavior Of The Lempel-Ziv Parsing Scheme And Digital Search Trees, Philippe Jaquet, Wojciech Szpankowski Dec 1993

Asymptotic Behavior Of The Lempel-Ziv Parsing Scheme And Digital Search Trees, Philippe Jaquet, Wojciech Szpankowski

Department of Computer Science Technical Reports

No abstract provided.

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