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Efficient Sequential And Parallel Algorithms For The Negative Cycle Problem, Dimitris Kavvadias, Grammati E. Pantziou, Paul G. Spirakis, Christos D. Zaroliagis Mar 1994

Efficient Sequential And Parallel Algorithms For The Negative Cycle Problem, Dimitris Kavvadias, Grammati E. Pantziou, Paul G. Spirakis, Christos D. Zaroliagis

Computer Science Technical Reports

We present here an algorithm for detecting (and outputting, if exists) a negative cycle in an $n$-vertex planar digraph $G$ with real edge weights. Its running time ranges from $O(n)$ up to $O(n^{1.5}\log n)$ as a certain topological measure of $G$ varies from $1$ up to $\Theta(n)$. Moreover, an efficient CREW PRAM implementation is given. Our algorithm applies also to digraphs whose genus $\gamma$ is $o(n)$.

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Videoscheme: A Research, Authoring, And Teaching Tool For Multimedia, J Matthews, F Makedon, P Gloor Mar 1994

Videoscheme: A Research, Authoring, And Teaching Tool For Multimedia, J Matthews, F Makedon, P Gloor

Computer Science Technical Reports

The availability of digital multimedia technology poses new challenges to researchers, authors, and educators, even as it creates new opportunities for rich communication. This paper suggests interactive computer programming as a fruitful approach to these challenges. VideoScheme, a prototype video programming environment, is described along with promising applications.

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Conference On A Disk: A Successful Experiment In Hypermedia Publishing (Extended Abstract), M Cheyney, P Gloor, D B. Johnson, F Makedon, J Matthews, P Metaxas Mar 1994

Conference On A Disk: A Successful Experiment In Hypermedia Publishing (Extended Abstract), M Cheyney, P Gloor, D B. Johnson, F Makedon, J Matthews, P Metaxas

Computer Science Technical Reports

Academic conferences are a long-standing and effective form of multimedia communication. Conference participants can transmit and recieve information through sight, speech, gesture, text, and touch. This same-time, same-place communication is sufficiently valuable to justify large investments in time and travel funds. Printed conference proceedings are attempts to recapture the value of a life conference, but they are limited by a fragmented and inefficient approach to the problem. We addressed this problem in the multimedia proceedings of the DAGS'92 conference. The recently published CD-ROM delibers text, graphic, audio, and video information as an integrated whole, with extensive provisions for random access …

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Decoding Linear Block Codes Using A Priority-First Search: Performance Analysis And Suboptimal Version, Yunghsiang S. Han, Carlos R.P. Hartmann, Kishan Mehrotra Mar 1994

Decoding Linear Block Codes Using A Priority-First Search: Performance Analysis And Suboptimal Version, Yunghsiang S. Han, Carlos R.P. Hartmann, Kishan Mehrotra

Electrical Engineering and Computer Science - Technical Reports

An efficient maximum-likelihood soft-decision decoding algorithm for linear block codes using a generalized Dijkstra's Algorithm was proposed by Han, Hartmann, and Chen. In this report we prove that this algorithm is efficient for most practical communication systems where the probability of error is less than 10-3 by finding an upper bound of the computation performance of the algorithm. A suboptimal decoding algorithm is also proposed. The performance of this suboptimal decoding algorithm is within 0.25 dB and 0.5 dB of the performance of an optimal decoding algorithm for the (104, 52) binary extended quadratic residue code and the (128, 64) …

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Dyadic Wavelet Features For Isolated Word Speaker Dependent Speech Recognition, Stephen Ainge Mar 1994

Dyadic Wavelet Features For Isolated Word Speaker Dependent Speech Recognition, Stephen Ainge

Theses and Dissertations

This research examines the use of dyadic wavelet features for the recognition of speaker dependent isolated word speech. The features were generated using three different wavelet filters-Daubechies 4 coefficient (Db4), Daubechies 20 coefficient (Db20) and a 31 coefficient cubic spline and three different window lengths-15ms, 8ms and 4ms. The accuracy of the standard and over-sampled dyadic wavelet methods were compared. The over-sampled dyadic wavelet method using the Db4 scaling function, with a maximum accuracy of 65.5, was found to be the most accurate of the wavelet methods tested. The accuracy of this over-sampled dyadic Db4 wavelet method was compared to …

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Effective Parallel Algorithm Animation, Paul W. Chase Mar 1994

Effective Parallel Algorithm Animation, Paul W. Chase

Theses and Dissertations

The AFIT Algorithm Animation Research Facility AAARF was developed by the Air Force Institute of Technology AFIT as a teaching aid for data structures and algorithm design. In particular, an extensive set of performance animations has been developed for the Intel iPSC Hypercube parallel processing system. This research focuses in part on developing animation support for discrete event simulation, mission routing, and evolutionary algorithms based on abstract representations of parallel algorithm behavior. The effort also builds extensions to the AAARF system and examines direction for further research. An innovative adaptable application-specific animation construction environment has been designed and implemented. The …

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Clustering Techniques In Speaker Recognition, Douglas N. Prescott Mar 1994

Clustering Techniques In Speaker Recognition, Douglas N. Prescott

Theses and Dissertations

This thesis presents a comparison based on identification rate, of three clustering techniques applied to cepstral features for speaker identification. LBG vector quantization as developed by Linde, Buzo and Gray; is used to provide benchmark performance for comparison with Fuzzy clustering (based on the unsupervised fuzzy partition-optimal number of classes, UFP-ONC algorithm by Gath and Geva) and an Artificial Neural Network, the Multilayer Perceptron. Cepstral features from the TIMIT, King and AFIT93 corpus speaker databases are used to produce speaker-identification classifiers using each of the clustering algorithms. The experiment reported evaluates the speaker identification performance using the 20-dimensional cepstral features …

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Application Of Sequential Quadratic Programming To Large-Scale Structural Design Problems, Mark A. Abramson Mar 1994

Application Of Sequential Quadratic Programming To Large-Scale Structural Design Problems, Mark A. Abramson

Theses and Dissertations

Large-scale structural optimization problems are often difficult to solve with reasonable efficiency and accuracy. Such problems are often characterized by constraint functions which are not explicitly defined. Constraint and gradient functions are usually expensive to evaluate. An optimization approach which uses the NLPQL sequential quadratic programming algorithm of Schittkowski, integrated with the Automated Structural Optimization System ASTROS is tested. The traditional solution approach involves the formulation and solution of an explicitly defined approximate problem during each iteration. This approach is replaced by a simpler approach in which the approximate problem is eliminated. In the simpler approach, each finite element analysis …

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A Simulation Approach To Granite Sentry System Analysis, Marilyn J. Bauer Mar 1994

A Simulation Approach To Granite Sentry System Analysis, Marilyn J. Bauer

Theses and Dissertations

This study demonstrated the use of simulation modelling to analyze Granite Sentry system performance. The availability simulation model constructed provides a number of system performance measures as a function of component MTBFs and MTTRs. Analysis of failure data prior to model construction supported the generally accepted use of exponentially distributed failure rates and lognormally distributed repair times.

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A Fortran Based Learning System Using Multilayer Back-Propagation Neural Network Techniques, Gregory L. Reinhart Mar 1994

A Fortran Based Learning System Using Multilayer Back-Propagation Neural Network Techniques, Gregory L. Reinhart

Theses and Dissertations

An interactive computer system which allows the researcher to build an optimal neural network structure quickly, is developed and validated. This system assumes a single hidden layer perceptron structure and uses the back- propagation training technique. The software enables the researcher to quickly define a neural network structure, train the neural network, interrupt training at any point to analyze the status of the current network, re-start training at the interrupted point if desired, and analyze the final network using two- dimensional graphs, three-dimensional graphs, confusion matrices and saliency metrics. A technique for training, testing, and validating various network structures and …

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Assessing The Vulnerability Of Multi-Commodity Networks With Failing Components, Alan R. Robinson Mar 1994

Assessing The Vulnerability Of Multi-Commodity Networks With Failing Components, Alan R. Robinson

Theses and Dissertations

This research proposes an analytical approach for assessing flow disturbance, or compromise, based on limited sampling of arc flow information in multi-commodity, or multiple origin-destination O-D, networks with failing arcs. There were three objectives established for this research. The first objective was to bound the expected flow, given the arcs fail with certain probabilities, which was accomplished by reviewing current approaches for single-commodity networks and extending the results to the multi-commodity case. The second objective was to determine the best placement of flow monitors to obtain the most accurate estimates of O-D pair volumes. This was accomplished using a multi-criteria …

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The Effective Use Of Animation In Simulation Model Validation, Christopher L. Swider Mar 1994

The Effective Use Of Animation In Simulation Model Validation, Christopher L. Swider

Theses and Dissertations

This study examined two animation displays moving icons, bar graphs at two presentation speeds to determine how each of these factors affected the animations ability to communicate violations of model assumptions. Subjects viewed animation displays individually and in combination at each presentation speed. Eight problem scenarios were presented to evaluate each animations ability to communicate violations of different assumptions. Each animations communication ability was measured subjectively and objectively. Subjective measures in the form of pairwise comparisons were used to calculate normalized preference ratings for each animation. objective measures included problem identification accuracy and problem time. Subjective results indicated that moving …

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Adaptive Execution Of Data Parallel Computations On Networks Of Heterogeneous Workstations, Robert Prouty, Steve Otto, Jonathan Walpole Mar 1994

Adaptive Execution Of Data Parallel Computations On Networks Of Heterogeneous Workstations, Robert Prouty, Steve Otto, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Parallel environments consisting of a network of heterogeneous workstations introduce an inherently dynamic environment that differs from multicomputers. Workstations are usually considered “shared” resources while multicomputers provide dedicated processing power. The number of workstations available for use is continually changing; the parallel machine presented by the network is in effect continually reconfiguring itself. Application programs must effectively adapt to the changing number of processing nodes while maintaining computational efficiency. This paper examines methods for adapting to this dynamic environment within the framework of explicit message passing under the data parallel programming model. We present four requirements which we feel a …

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A Topology-Aware Collision Resolution Algorithm, Lewis Barnett Iii Mar 1994

A Topology-Aware Collision Resolution Algorithm, Lewis Barnett Iii

Department of Math & Statistics Technical Report Series

A new collision resolution algorithm called the Space Division Multiple Access protocol (SDMA) is presented. SDMA gains a performance advantage over similar protocols by using information about the positions of stations on the network. The protocol can operate asynchrononsly on a broadcast bus, allowing variable sized packet traffic. Through simulation the protocol is demonstrated to have better performance than Ethernet and the Capetanakis Tree protocol, a similar collision resolution protocol, under some traffic conditions. In particular, under heavy loads, SDMA displays better average throughput and lower variance of delay than Ethernet. The protocol demonstrates a performance bias based on the …

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Edge Weight Reduction Problems In Directed Acyclic Graphs, Susanne E. Hambrusch, Hung-Yi Tu Mar 1994

Edge Weight Reduction Problems In Directed Acyclic Graphs, Susanne E. Hambrusch, Hung-Yi Tu

Department of Computer Science Technical Reports

No abstract provided.

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Average Profile And Limiting Distribution For A Phrase Size In The Lempel-Ziv Parsing Algorithm, Guy Louchard, Wojciech Szpankowski Mar 1994

Average Profile And Limiting Distribution For A Phrase Size In The Lempel-Ziv Parsing Algorithm, Guy Louchard, Wojciech Szpankowski

Department of Computer Science Technical Reports

No abstract provided.

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A Study Of Distributed Transaction Processing In Wide Area Network, Bharat Bhargava, Yongguang Zhang Mar 1994

A Study Of Distributed Transaction Processing In Wide Area Network, Bharat Bhargava, Yongguang Zhang

Department of Computer Science Technical Reports

No abstract provided.

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Writing, Supporting, And Evaluating Tripwire: A Publically Available Security Tool, Gene H. Kim, Eugene H. Spafford Mar 1994

Writing, Supporting, And Evaluating Tripwire: A Publically Available Security Tool, Gene H. Kim, Eugene H. Spafford

Department of Computer Science Technical Reports

No abstract provided.

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A Geometric Approach To Molecular Docking And Similarity, Chandrajit Bajaj, Fausto Bernardini, Kokichi Sugihara Mar 1994

A Geometric Approach To Molecular Docking And Similarity, Chandrajit Bajaj, Fausto Bernardini, Kokichi Sugihara

Department of Computer Science Technical Reports

No abstract provided.

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Thread Migration On Heterogeneous Systems Via Compile-Time Transformations, Janche Sang, Geoffrey W. Peters, Vernon J. Rego Mar 1994

Thread Migration On Heterogeneous Systems Via Compile-Time Transformations, Janche Sang, Geoffrey W. Peters, Vernon J. Rego

Department of Computer Science Technical Reports

No abstract provided.

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Recognition In Science And Engineering, John R. Rice Mar 1994

Recognition In Science And Engineering, John R. Rice

Department of Computer Science Technical Reports

No abstract provided.

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The Parallel Envelope, M.G. Rossmann, M. A. Cornea-Hasegan, D. C. Marinsecu, Z. Zhang, Robert E. Lynch, J. Muckelbauer, R. Mckenna, S. Munshi, J-B. Dai Mar 1994

The Parallel Envelope, M.G. Rossmann, M. A. Cornea-Hasegan, D. C. Marinsecu, Z. Zhang, Robert E. Lynch, J. Muckelbauer, R. Mckenna, S. Munshi, J-B. Dai

Department of Computer Science Technical Reports

No abstract provided.

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Pdelab: An Object-Oriented Framework For Building Problem Solving Environments For Pde Based Applications, Sanjiva Weerawarana, Elias N. Houstis, John. R. Rice, Ann Christine Catlin, Cheryl L. Crabill, Chi Ching Chui Mar 1994

Pdelab: An Object-Oriented Framework For Building Problem Solving Environments For Pde Based Applications, Sanjiva Weerawarana, Elias N. Houstis, John. R. Rice, Ann Christine Catlin, Cheryl L. Crabill, Chi Ching Chui

Department of Computer Science Technical Reports

No abstract provided.

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Re-Evaluating Indexing Schemes For Nested Objects, Yin-He Jiang, Xiangning Liu, Bharat Bhargava Mar 1994

Re-Evaluating Indexing Schemes For Nested Objects, Yin-He Jiang, Xiangning Liu, Bharat Bhargava

Department of Computer Science Technical Reports

No abstract provided.

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Quickest Paths: Faster Algorithms And Dynamization, Dimitrios Kagaris, Grammati E. Pantziou, Spyros Tragoudas, Christos D. Zaroliagis Mar 1994

Quickest Paths: Faster Algorithms And Dynamization, Dimitrios Kagaris, Grammati E. Pantziou, Spyros Tragoudas, Christos D. Zaroliagis

Computer Science Technical Reports

Given a network $N=(V,E,{c},{l})$, where $G=(V,E)$, $|V|=n$ and $|E|=m$, is a directed graph, ${c}(e) > 0$ is the capacity and ${l}(e) \ge 0$ is the lead time (or delay) for each edge $e\in E$, the quickest path problem is to find a path for a given source--destination pair such that the total lead time plus the inverse of the minimum edge capacity of the path is minimal. The problem has applications to fast data transmissions in communication networks. The best previous algorithm for the single--pair quickest path problem runs in time $O(r m+r n \log n)$, where $r$ is the number …

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A Format For Storing And Managing Multiple Level Of Detail Terrain For Simulated Environments, Keith L. Meissner Mar 1994

A Format For Storing And Managing Multiple Level Of Detail Terrain For Simulated Environments, Keith L. Meissner

Theses and Dissertations

This study investigated a method of storing, managing and rendering terrain data, while addressing conflicting goals of. rendering speed, display detail and memory usage. A data structure is presented to store terrain data, with an object oriented system to manage the data stored in the structure. The structure stores terrain data in a compact form which is converted into rendering structures in real time. The structure uses levels of detail to maintain display detail. The structure is compared against an existing format for storing terrain data, MultiGen Flight. The system managing the structure is shown to decrease memory usage and …

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Automating Output Size And Reuse Metrics In A Repository-Based Computer-Aided Software Engineering (Case) Environment, R. D. Banker, Robert J. Kauffman, C. Wright, D. Zweig Mar 1994

Automating Output Size And Reuse Metrics In A Repository-Based Computer-Aided Software Engineering (Case) Environment, R. D. Banker, Robert J. Kauffman, C. Wright, D. Zweig

Research Collection School Of Computing and Information Systems

Measurement of software development productivity is needed in order to control software costs, but it is discouragingly labor-intensive and expensive. Computer-aided software engineering (CASE) technologies-especially repository-based, integrated CASE-have the potential to support the automation of this measurement. We discuss the conceptual basis for the development of automated analyzers for function point and software reuse measurement for object-based CASE. Both analyzers take advantage of the existence of a representation of the application system that is stored within an object repository, and that contains the necessary information about the application system. We also discuss metrics for software reuse measurement, including reuse leverage, …

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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 …

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A Reduction Semantics For Array Expressions:The Psi Compiler, L. Mullin, S. Thibault Feb 1994

A Reduction Semantics For Array Expressions:The Psi Compiler, L. Mullin, S. Thibault

Computer Science Technical Reports

No abstract provided.

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Formal Verification Of Distributed Deadlock Detection Algorithm Using A Time-Dependent Proof Technique, Pei-Yu Li, Bruce Mcmillin Feb 1994

Formal Verification Of Distributed Deadlock Detection Algorithm Using A Time-Dependent Proof Technique, Pei-Yu Li, Bruce Mcmillin

Computer Science Technical Reports

A large number of published distributed deadlock detection/resolution algorithms are found to be incorrect because they have used informal approaches to prove the correctness of their algorithms. In this paper, we present a formal approach for the correctness proof and give an example of the proof. In this proposed approach, a formal model of distributed deadlock is presented with a local-time deadlock specification for correctness verification. With the formal model, we have an insight into the definition of deadlock in local views which is used to show the existence of a real deadlock. A rigorous proof to show the equivalence …

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