Digital Commons Network^™

Parametricity And Local Variables, Peter W. O'Hearn, R. D. Tennent

Electrical Engineering and Computer Science - Technical Reports

We propose that the phenomenon of local state may be understood in terms of Strachey's concept of parametric (i.e., uniform) polymorphism. The intuitive basis for our proposal is the following analogy: a non-local procedure is independent of locally-declared variables in the same way that a parametrically polymorphic function is independent of types to which it is instantiated. A connection between parametricity and representational abstraction was first suggested by J. C. Reynolds. Reynolds used logical relations to formalize this connection in languages with type variables and user-defined types. We use relational parametricity to construct a model for an Algol-like language in …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 9, Number 8, October 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.

Semantics-Based Information Brokering: A Step Towards Realizing The Infocosm, Vipul Kashyap, Amit P. Sheth

Kno.e.sis Publications

The rapid advances in computer and communication technologies, and their merger, is leading to a global information market place. It will consist of federations of very large number of information systems that will cooperate to varying extents to support the users' information needs. We propose an architecture which may facilitate meeting these needs. It consists of three main components: information providers, information brokers and information consumers. We also propose an approach to information brokering. We discuss two of it's tasks: information resource discovery, which identities relevant information sources for a given query, and query processing, which involves the generation of …

Mobile-Process Based Distributed Memory Simulations, Janche Sang, Edward Mascarenhas, Vernon J. Rego

Department of Computer Science Technical Reports

No abstract provided.

Scheduling With Compensation In Multi- Database Systems, Aidong Zhang, Bharat Bhargava

Department of Computer Science Technical Reports

No abstract provided.

A Characterization Of Connecting Maps As Nonlinear Roots Of The Identity, J. Peters

Department of Computer Science Technical Reports

No abstract provided.

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.

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 …

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 …

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.

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 …

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 …

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 …

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 …