Digital Commons Network^™

Efficient Implementation Of Thread Migration On Distributed-Memory Multi-Processors, Janche Sang, Vernon J. Rego

Department of Computer Science Technical Reports

No abstract provided.

Visualizing Object Oriented Software In Three Dimensions, Colin Ware, David Hui, Glenn Franck

Center for Coastal and Ocean Mapping

There is increasing evidence that it is possible to perceive and understand increasingly comple x information systems if they are displayed a s graphical objects in a three dimensional space . Object-oriented software provides an interestin g test case - there is a natural mapping fro m software objects to visual objects . In this paper we explore two areas. 1) Information perception : we are running controlled experiments to determine empirically if our initial premise is valid; how much more (or less) can be understoo d in 3D than in 2D? 2) Layout: our strategy is to combine partially …

Cyclo-Static Scheduling Of Large Grain Dataflow Algorithms On A Local Area Atamm Multicomputing Testbed, Sudeepto Roy

Electrical & Computer Engineering Theses & Dissertations

A strategy for cyclo-statically scheduling deterministic large grain dataflow (LGDF) algorithms for distributed execution on loosely coupled multicomputer architectures is presented in this research. The computational paradigm used is the ODU/NASA developed Algorithm To Architecture Mapping Model (ATAMM), which consists of marked graphs and Gantt chart representations that model the iterative execution of deterministic LGDF algorithms for different values of throughput and computation time. It is postulated that the behavior of these algorithms could be represented by the aggregate execution of an ensemble of cyclically shifted threads of a specific node sequence. Assuming the existence of one or more such …

Comparative Study Of Louville And Symplectic Integrators, Daniel I. Okunbor

Computer Science Technical Reports

In this paper, we construct an integrator that conserves volume in phase space. We compare the results obtained using this method and a symplectic integrator. The results of our experiments do not reveal any superiority of the symplectic over strictly volume-preserving integrators. We also investigate the effect of numerically conserving energy in a numerical process by rescaling velocities to keep energy constant at every step. Our results for Henon-Heiles problem show that keeping energy constant in this way destroys ergodicity and forces the solution onto a periodic orbit.

Constructing An Interval Temporal Logic For Real-Time Systems, Grace Tsai, Matt Insall, Bruce M. Mcmillin

Computer Science Technical Reports

A real-time system is one that involves control of one or more physical devices with essential timing requirements. Examples of these systems are command and control systems, process control systems, flight control systems, and the space shuttle avionics systems. The characteristics of these systems are that severe consequences will occur if the logical and physical timing specifications of the systems are not met.

Formal specification and verification are among the techniques to achieve reliable software for real-time systems, in which testing may be impossible or too dangerous to perform. This paper presents a modal logic, Interval Temporal , built upon …

Structured And Object-Oriented Methodologies: A Comparative Analysis Based On A Case Study, Gary Brian Warren

Honors Capstone Projects and Theses

No abstract provided.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 9, Number 7, September 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.

Rsvp: A New Resource Reservation Protocol, Daniel Zappala, Stephen Deering, Deborah Estrin, Scott Shenker, Lixia Zhang

Faculty Publications

The current Internet architecture, embodied in the Internet Protocol (IP) network protocol, offers a very simple service model: point-to-point best-effort service. In recent years, several new classes of distributed applications have been developed, such as remote video, multimedia conferencing, data fusion, visualization, and virtual reality. It is becoming increasingly clear that the Internet’s primitive service model is inadequate for these new applications. This inadequacy stems from the failure of the point-to-point best-effort service model to address two application requirements. First, many of these applications are very sensitive to the quality of service their packets receive. For a network to deliver …

Entity Identification In Database Integration: An Evidential Reasoning Approach, Ee Peng Lim, Jaideep Srivastava

Research Collection School Of Computing and Information Systems

Entity identification is the problem of matching object instances from different databases which correspond to the same real-world entity. In this paper, we present a 2-step entity identification process in which attributes for matching tuples may be missing in certain tuples, and thus need to be derived prior to the matching. To match tuples, we require identity rules which specify the conditions to be satisfied by a pair of tuples, from different databases, before they can be considered as modeling the same real-world entity. We also introduce ILFD's (instance-level functional dependencies) as a form of inference rules which derive the …

On The Automation Of Object-Oriented Requirements Analysis, Nancy L. Crowley

Theses and Dissertations

The research investigated the possibility that an object-oriented requirements analysis (OORA) specification model can be represented in a computer system and used as a basis for the elicitation of the information necessary for the development of an object-oriented specification for a particular problem. The proof-of-concept system developed is called the OORA automated Knowledge System (OAKS). OAKS contains a generic domain model that is modified to satisfy a particular problem in the domain. The core of OAKS is a reusable domain model, which represents a domain of interest. The domain model is used as a basis for user changes that are …

Modeling Flexibility In Distributed Transactions, Ahmed Elmagarmid, Aidong Zhang

Department of Computer Science Technical Reports

No abstract provided.

Softlab - A Virtual Laboratory For Computational Science, Christoph M. Hoffmann, Elias N. Houstis, John R. Rice, Ann Christine Catlin, Margaret Gaitatzes, N-H. Linda Wang, Christos G. Takoudis, David G. Taylor

Department of Computer Science Technical Reports

No abstract provided.

Some Applications Of Constructive Real Algebraic Geometry, Chandrajit L. Bajaj

Department of Computer Science Technical Reports

No abstract provided.

Semantic Problems Of Generative, Constraint Based Design, Christoph M. Hoffmann

Department of Computer Science Technical Reports

No abstract provided.

A Distributed Memory Algorithm For 3-D Fft, Calin R. Costian, Dan C. Marinescu

Department of Computer Science Technical Reports

No abstract provided.

Gencray Language Reference Manual, Version 2, Sanjiva Weerawarana, Ann C. Catlin, Elias N. Houstis, John R. Rice

Department of Computer Science Technical Reports

No abstract provided.

Wavelet Localization Of The Radon Transform, Tim Olson, Joe Destefano

Computer Science Technical Reports

In this paper we develop an algorithm which significantly reduces radiation exposure in x-ray tomography, when a local region of the body is to be imaged. The algorithm uses the properties of wavelets to essentially localize the Radon transform. The algorithm differs from previous algorithms for doing local tomography because it recovers an approximation to the original image, not the image modulo the nullspace of the local tomography operator, or the Lambda transform of the image. This is possible because we do not truly invert the interior Radon transform, but rather sample the Radon transform sparsely away from the local …

Computerized Vehicle Routing Programs And Their Effect On Vehicle Utilization In The Air Force, Rex E. Adee, William G. Howard

Theses and Dissertations

The purpose of this study is to determine if a commercial computerized vehicle routing program improves vehicle utilization for an Air Force base transportation organization. First, the researchers investigate current routing procedures of Air Force base transportation organizations. Second, researchers identify a commercial computerized vehicle routing program that enables the authors to conduct a comparison of vehicle utilization rates between an Air Force base transportation organization and commercial computerized vehicle routing programs. The study reveals that implementing a computerized vehicle routing program in place of a manual routing procedure does not improve vehicle utilization. However, the study reveals some limitations …

Hybrid Arq Schemes For Point-To-Multipoint Communications Over Nonstationary Broadcast Channels, Robert H. Deng

Research Collection School Of Computing and Information Systems

Hybrid automatic-repeat-request (ARQ) error control schemes make use of both error detection and error correction in order to achieve high throughput and low undetected error probabilities on two way channels. Two hybrid ARQ schemes, termed hybrid go-back-N (HGB- N) and hybrid selective-repeat (HSR), are proposed for point-to-multipoint communications over broadcast channels. Both schemes incorporate a concatenated code for error correction and error detection. The performance study of the hybrid schemes is based on a two-state Markov model of a burst noise channel. An analytic solution is derived for the throughput efficiency of the HSR scheme, while approximations and computer simulation …

Data Dependence In Programs Involving Indexed Variables, Borislav Nikolik

Dissertations and Theses

Symbolic execution is a powerful technique used to perform various activities such as program testing, formal verification of programs, etc. However, symbolic execution does not deal with indexed variables in an adequate manner. Integration of indexed variables such as arrays into symbolic execution would increase the generality of this technique. We present an original substitution technique that produces array-term-free constraints as a counterargument to the commonly accepted belief that symbolic execution cannot handle arrays. The substitution technique deals with constraints involving array terms with a single aggregate name, array terms with multiple aggregate names, and nested array terms. Our approach …

Implicit Methods On Parallel Processors, Larry Reeves

Computer Science Technical Reports

Since most partial differential equations (PDEs) do not have exact solutions, they are usually solved by some type of numerical method. Since a numerical method is commonly built from finite difference approximations derived from Taylor series expansions, such a development is derived. Stability and convergence of these methods is defined and the rate of convergence is defined and shown for a few simple methods. Of particular importance is the difference between implicit and explicit methods. Finally, the current applications and adaptations of implicit methods on parallel processors are examined and their strengths and weaknesses discussed.

Evaluating The Effectiveness Of Certain Metrics In Measuring The Quality Of End User Documentation, Ronald Morrison

Dissertations and Theses

Traditional methods of evaluating quality in computer end user documentation have been subjective in nature, and have not been widely used in practice. Attempts to quantify quality and more narrowly define the essential features of quality have been limited -- leaving the issue of quality largely up to the writer of the user manual.

Quantifiable measures from the literature, especially Velotta (1992) and Brockman (1990), have been assembled into a set of uniformly weighted metrics for the measurement of document quality. This measure has been applied to the end user documentation of eighty-two personal computer packages. End user documentation is …

Formal Model And Specification Of Deadlock, Pei-Yu Li, Bruce M. Mcmillin

Computer Science Technical Reports

In this paper, we present a formal model of deadlock in a distributed system and develop the deadlock specification in terms of time-dependent predicates. Primitive activities of processes in the distributed system are specified by the predicates so that system behaviors can be described by logic operations. With the formal model, we have an insight into the definition of deadlock in local views. A rigorous proof to show the equivalence of local-time and global-time deadlock specifications is presented. The local-time deadlock specification, which defines the timing of dependence between deadlocked processes, will be useful in the correctness verification of distributed …

Specifying And Enforcing Intertask Dependencies, Paul Attie, Munindar Singh, Amit P. Sheth, Marek Rusinkiewicz

Kno.e.sis Publications

Extensions of the traditional atomic transaction model are needed to support the development of multi-system applications or workflows that access heterogeneous databases and legacy application systems. Most extended transaction models use conditions involving events or dependencies between transactions. Intertask dependencies can serve as a uniform framework for defining extended transaction models. In this paper we introduce event attributes needed to determine whether a dependency is enforceable and to properly schedule events in extended transaction models. Using these attributes and a formalization of a dependency into the temporal logic CTL, we can automatically synthesize an automaton that captures the computations that …

Measuring The Effects Of Thread Placement On The Kendall Square Ksr1, Amy Apon, T D. Wagner, E Smirni, M Madhukar, L W. Dowdy

Publications

This paper describes a measurement study of the effects of thread placement on memory access times on the Kendall Square multiprocessor, the KSRl. The KSRl uses a conventional shared memory programming model in a distributed memory architecture. The architecture is based on a ring of rings of 64-bit superscalar microprocessors. The KSRl has a Cache-Only Memory Architecture (COMA). Memory consists of the local cache memoria attached to each processor. Whenever an address is accessed, the data item is automatically copied to the local cache memory module, 80 that access times for subsequent references will be minimal. If a local cache …

Facial Image Retrieval, Identification, And Inference System, Jian Kang Wu, Yew Hock Ang, Chiam Prong Lam, S. K. Moorthy, Arcot Desai Narasimhalu

Research Collection School Of Computing and Information Systems

Recognition of a human face is very easy even to a child, but is extremely difficult for computers. Here we present a Computer Aided Facial Image Identification, Retrieval and Inference System (CAFIIRIS) for criminal identification. The system stores and manages facial images and criminal records, providing necessary image and text processing, and editing tools. Inference of facial images of different ages of a person is also possible. Access to facial images can be done via key words, fuzzy descriptions, and visual browsing.

A Survey Of Expert Systems In Singapore And The Integration Of Multimedia Technology And Expert Systems, Arcot Desai Narasimhalu

Research Collection School Of Computing and Information Systems

Expert systems technologies have been widely adopted by different industries form the early 1980s. There have been examples of expert systems embedded in applications developed for the financial and banking sector, manufacturing, services and government. In section 2 of this paper, we present a scan of expert systems used in different sectors. Section 3 will cover the expert system tools and applications developed in the decade of the 1980s. Section 4 will present some of the ongoing expert systems related activities. Section 5 will extrapolate the present work to forecast the future types of expert systems that might be developed …

Memory-Adaptive External Sorting, Hwee Hwa Pang, Michael J. Carey, Miron Livny

Research Collection School Of Computing and Information Systems

In real-time and goal-oriented database systems, the amount of memory assigned to queries that sort or join large relations may fluctuate due to contention from other higher priority transactions. This study focuses on techniques that enable external sorts both to reduce their buffer usage when they lose memory, and to effectively utilize any additional buffers that are given to them. We also show how these techniques can be extended to work with sort-merge joins. A series of experiments confirms that our proposed techniques are useful for sorting and joining large relations in the face of memory fluctuations.

Distributed And Collaborative Volume Visualization, Vinod Anupam, Chandrajit Bajaj, Daniel Schikore, Matthew Schikore

Department of Computer Science Technical Reports

No abstract provided.

Global Committability In Multidatabase Systems, O. Bukhres, Ahmed K. Elmagarmid, J. Jing, W. Kim, A. Zhang

Department of Computer Science Technical Reports

No abstract provided.