Digital Commons Network^™

Reasoning About Places, Times, And Actions In The Presence Of Mobility, C. Donald Wilcox, Gruia-Catalin Roman

All Computer Science and Engineering Research

The current trend toward portable computing systems (e.g., cellular phones, laptop computers) brings with it the need for a new paradigm for thinking about designing distributed applications. We introduce the term mobile to refer to distributed systems that include moving, autonomous agents which loosely cooperate to accomplish a tastk. The fluid nature of hte interconnections between components in a mobile system provides new challenges and new opportunities for the research community. While we do not propsoe to have fully grasped the consequences of these systems, we believe that the notions of place, time, and action will be central in any …

Boxgraph: A Two-Dimensional Visual Computation Model, Takayuki Dan Kimura, Timothy B. Brown

All Computer Science and Engineering Research

Traditional computation models such as Turing machines, lambda-calculus, Markov's normal algorithms, are not suitable models for visual programming languages because they are all based on one-dimensional text strings and visual programming uses two-dimensional graphic diagrams. We propose a two-dimensional computation model, called Boxgraph, that requires no text. The syntax of the model consists of nested boxes connected by arrows, and the semantics consists of dataflow and the concept of consistency. The expressive power of the model is demonstrated by constructing representations of a binary full adder, the Fibonacci function, and the GCD function. The model, with a small extension to …

Production Quality Video Over Broadband Networks: A Description Of The System And Two Interactive Applications, William D. Richard, Jerome R. Cox Jr., A. Maynard Engebretson, Jason Fritts And Brian L. Gottlieb And Craig Horn

All Computer Science and Engineering Research

The Washington University MultiMedia eXplorer (MMX) is a complete, host-independent multimedia system capable of transmitting and receiving JPEG-compressed video, CD-quality audio, and high-resolution radiographic images over the Washington University broadband ATM network. If the host is equipped with an ATM interface card, normal network traffic can be supported via an ATM extension port on the MMX. The major components of the MMX are an ATMizer and three multimedia channels. The ATMizer implements the host interface, the interface to the ATM network, and hte interface to the three multimdeia channels. This paper describes the architecture of the MMX, the software used …

Visual Presentation Of Software Specifications And Designs, Gruia-Catalin Roman, Delbert Hart, Charles Calkins

All Computer Science and Engineering Research

Formal methods hold the promise for high dependability in the design of critical software. However, software engineers who employ formal methods need to communicate their design decisions to users, customers, managers, and collegues who may not be in a position to acquire a full understanding of the formal notation being used. Visualizations derived from formal specifications and designs must be able to convey the required information precisely and reliably without the use of formal notation. This paper discusses a design methodology which attempts to integrate a design methodology based upon specification and program refinement with a state-of-the-art approach to rapid …

Performance Comparison Of Asynchronous Adders, Mark A. Franklin, Tienyo Pan

All Computer Science and Engineering Research

In asynchronous systems, average function delays principally govern overall throughput. This paper compares the performance of six adder designs with respect to their average delays. Our results show that asynchronous addres (32 or 64-bits) with a hybrid structure (e.g., carry-select addres) run 20-40% faster than simple ripple-carry addres. Hybrid adders also outperform high-cost, strictly synchronous conditional-sum adders.

An Application-Oriented Error Control Scheme For High Speed Networks, Fengmin Gong, Gurudatta Parulkar

All Computer Science and Engineering Research

Many new network applications demand interprocess communication (IPC) services that are not supported by existing transport protocol mechanisms. Large bandwidth-delay products of high-speed networks also render the existing control mechanisms such as flow and error control less efficient. In particular, new error control schemes that can provide variable degrees of error recovery according to the applications requirements are needed. This paper presents the design, evaluation, and implementation of an application-oriented error control scheme that is aimed at supporting efficient IPC in high-speed networking environments. Our results show that the proposed error control scheme allows effective control of trade-off between the …

Practical Methods For Approximating Shortest Paths On A Convex Polytope In R3, John Hershberger, Subhash Suri

All Computer Science and Engineering Research

We propose a n extremely simple approximation scheme for computing shortest paths on the surface of a convex polytope in three dimensions. Given a convex polytope P with n vertices and two points p,q on its surface, let dp (p,q) denote the shortest path distance between p and q on the surface of P. Our algorithm produces a path of length at most 2 × dp(p,q) in time O(n). Extending this results, we can also compute ana pproximation of the shortest path tree rooted at an arbitrary point χ Є P in time O(n log n). In the approximate tree, …

Speculative Computation: Overcoming Communication Delays In Parallel Algorithms, Vasudha Govindan, Mark A. Franklin

All Computer Science and Engineering Research

Communication latencies and delays are a major source of performance degradation in parallel computing systems. It is importnat to "mask" these communication delays by overlapping them with useful computation in order to obtain good parallel performance. This paper proposes speculative computation as a technique to mask communication latencies. Speculative computation is discussed in the context of synchronous iterative algorithms. Processors speculate the contents of messages that are not hyet received and perform computation based on the speculated values. When the messages are received, they are compared with the speculated values and, if the error is unacceptable, the resulitng computation is …

An Incremental Distributed Algorithm For Computing Biconnected Components, Bala Swaminathan, Kenneth J. Goldman

All Computer Science and Engineering Research

This paper describes a distributed algorithm for computing the biconnected components of a dynamically changing graph. Our algorithm has a worst case communication complexity of O(b + c) messages for an edge insertion and O(b' + c) messages for an edge removal, and a worst case time complexity of O(c) for both operations, where c is the maximum number of biconnected components in any of the connected components during the operation, b is the number of nodes in the biconnected component containing the new edge, and bprime is the number of nodes in the biconnected component in which the update …

An Evaluation Of The Pavane Visualization System, Kenneth C. Cox, Gruia-Catalin Roman

All Computer Science and Engineering Research

The Pavane program visualization system is an implementation of the declarative paradigm of visualization. After a brief report on the status of the Pavane implementation, we present the results of an evaluation of the usability of Pavane. This evaluation is based on the use of Pavane by its developers to construct program visualizations, on its use in a classroom setting as a tool for examining executing programs, and on its application to some simple scientific visualizations.

Learning And Teaching Of Boolean And Geometric Classes, H. David Mathias

All Computer Science and Engineering Research

We consider the concept classes of DNF formulas and unions of discretized, axis-parallel d-dimensional boxes in discretized d-dimensional space with respect to several different learning models. In the model of learning with queries we present an algorithm to learn unions of boxes. We introduce a model of teaching that prevents illicit communication between the teacher and the leaner but that captures the intuitive aspect of teaching: a learner should perform at least as well with a cooperative teacher as with an adversarial teacher. We propose the study of teaching of DNF formulas and unions of boxes in this model. We …

Distributed Multimedia Systems Research Prospectus, Jonathan Turner

All Computer Science and Engineering Research

Distributed multimedia computing and communiation systems combine computer systems, networks and distributed software to facilitate applications that enable and enhance collaborative work, direct interpersonal communication, remote access to information and real-time presentation of information from a variety of sources. Over the next decade, we expect such systems to become central to the infrastructure of our increasingly information-driven society. This prospectus describes a program of research being pursued within the Computer and Communications Research Center of Washington University and the Departments of Computer Science and Electrical Engineering. This program seeks to promote the creation of effective distributed multimedia systems and develop …

Connection Management In Reconfigurable Distributed Systems, Bala Swaminathan

All Computer Science and Engineering Research

The Programmer's Playground takes a new approach to simplifying and supporting the construction of distributed applications. The approach, called I/O abstraction, separates the description of a system's communication structure from the descriptions of its computational components so that software modules written in existing programming languages cna be integrated flexibly and dynamically by both programmers and end-users. This separation is achieved by estabishing logical connectinos among the data interfaces of independent software modules. The logical connections provide a uniform high-level view of communication for both discrete and continuous data. The I/O abstraction approach inherits ideas from the I/O automaton model, a …

Proposal For Research Distribution Of Gigabit Network Technology, Jonathan Turner

All Computer Science and Engineering Research

In 1993, APRA funded a major program at Washingotn University to create gigabit networking technology and create a gigabit testbed based on this technology. This program is now nearing the end of its first year and is making excellent proress towards its research and technical objectives. This note a proposes a program that would lead to the export of this technology to research groups in networking and gigabit applications with an interest in using it to further their own research activities.

Scheduling In A Ring With Unit Capacity Links, Perry Fizzano, Clifford Stein

Computer Science Technical Reports

We consider the problem of scheduling unit-sized jobs on a ring of processors with the objective of minimizing the completion time of the last job. Unlike much previous work we place restrictions on the capacity of the network links connecting processors. We give a polynomial time centralized algorithm that produces optimal length schedules. We also give a simple distributed 2-approximation algorithm.

The Design And Development Of Interactive Multimedia Conference Proceedings, Samuel A. Rebelsky, James Ford, Kenneth Harker, Fillia Makedon, P Takis Metaxas, Charles Owen

Computer Science Technical Reports

Many conferences are now providing electronic proceedings. Often, these proceedings are little more than electronic collections of documents put together in a standard software package, such as SuperBook or Acrobat. This means that few of these proceedings incorporate the full range of materials that a conference generates. Furthermore, because these general interfaces are not designed for conference proceedings, they do not provide all the features a conference warrants.

The interactive multimedia proceedings for the DAGS'92 Institute on Parallel Computation used an interface designed specifically for presenting conference materials and provided both talks (audio, video, and slides) and papers (in hypertext …

Linear Codes And Error-Correction, Karen Brown

Presidential Scholars Theses (1990 – 2006)

The process of encoding information for transmission from one source to another is a vital process in many areas of science and technology. Whenever coded information is sent, there arises a certain possibility that an error will occur, either during transmission or in decoding. Therefore, it is imperative to develop methods to detect and correct errors in a code. The study of coding theory is a "new" area of mathematics which is relatively undeveloped.

This paper focuses on the properties of linear codes -and their corresponding methods of error-correction. To simplify the issue, only binary block codes are studied; hence …

A Study Of The Approaches And Attitudes Of Information Systems Executives To Measuring Information Systems Effectiveness, Falantina Tjakra

Theses: Doctorates and Masters

The purpose of the research is to examine the attitudes of IS executives to the current and future importance of some of the approaches to measuring IS efficiency and IS effectiveness in large Australian organisations. The study identified the nature of IS effectiveness approaches along the lines of whether they are business-oriented, IS internal/operational, financial, quantitative or qualitative measures. It also examined whether the structure of the IS management and industry sector had an effect on attitudes towards these measures.

Translation Of Semantic Aspects Of Oodini Graphical Representation To Onto Oodb Data Definition Language, Xiaoyong Wang

Theses

In this thesis we present a system to translate the semantic elements in the graphical schema language of OODINI from API of OODAL to the Type definition of ONTOS DB. To translate semantic constraints of the graphical language, we patch more information to existent class data structure in API of OODAL. After a brief review of OODINI, ONTOS DB and the existent translator without the ability to translate semantic constraints, we describe in detail the methods to translate the essential relationship. dependent relationship, multi-valued essential relationship and multi-valued dependent relationship. We employ an Inverse Reference to a "Set of" Type …

A Strategic Plan For Computing And Telecommunications At A University, Dennis J. Huff

CCAC Theses and Dissertations

Embry-Riddle Aeronautical University (ERAU), a multi-campus, four-year institution of higher education specializing in aeronautic and avionic engineering, has recently made a strong commitment to integration of technology into the University environment. Due to a present lack of vision and planning, ERAU secured the services of Technology Specialists, Inc. (TSI) to manage the technology center and develop a five year plan for technology integration. The author was instrumental in the planning and development of the plan. As research has confirmed, technology planning has traditionally been lacking in higher education institutions. The author followed a method for plan development as suggested by …

The Design Of An Effective, Economical Executive Information System For Cedarville College, David L. Rotman

CCAC Theses and Dissertations

The managers of a corporation have an obligation to make the best use of available organizational resources for daily operational activities of the corporation and for long-range development. This requirement for efficient management certainly obtains for higher education, as declining student populations and shrinking funding sources argue for an even greater need to manage well. One important aspect of efficient management is having sufficient information for decision making. This dissertation addresses the need for electronic tools to assist officers of a higher education institution in the management of the institution by improving access to information. College administrators need information about …

Managing Risks In Information Technology Projects, Boon Siong Neo, Kwong Sin Leong

Research Collection School Of Accountancy

The development and implementation of IT (Information Technology) projects are plagued with problems of cost and time overruns. technical inadequacy, inability to meet user requirements. lack of utilization. and failure to achieve anticipated benefits. These problems occur to some projects and not to others because I) IT projects have different profiles of risk. and 2) IT project risks have been managed more or less effectively. This paper synthesizes the literature into four classes of risks. and applies it to evaluate TradeNet. an EDLbased trading system implemented in Singapore in I989. Through a case study of TradeNet. we derived a typology …

Design Of An Application Development Toolkit For Hpf/Fortran 90d, Manish Parashar, Salim Hariri, Tomasz Haupt, Geoffrey C. Fox

Northeast Parallel Architecture Center

The development of efficient application software capable of exploiting available High Performance Computing (HPC) systems is non-trivial and is largely governed by the availability of sufficiently high-level languages, tools, and application development environments. In this paper we describe the design and operation of a toolkit for HPF/Fortran 90D application development. The toolkit incorporates the following systems: (1) ESP: An Interpretive Framework for HPF/Fortran 90D Performance Prediction; (2) ESP-i: A HPF/Fortran 90D Functional Interpreter; and (3) ESPial: An Integrated Environment for HPF/Fortran 90D Application Development & Execution. The toolkit has been implemented on the iPSC/860 hypercube system, and is supported by …

Interpreting The Performance Of Hpf/Fortran 90d, Manish Parashar, Salim Hariri, Tomasz Haupt, Geoffrey C. Fox

Northeast Parallel Architecture Center

In this paper we present a novel interpretive approach for accurate and cost-effective performance prediction in a high performance computing environment, and describe the design of a source-driven HPF/Fortran 90D performance prediction framework based on this approach. The performance prediction framework has been implemented as part of a HPF/Fortran 90D application development environment. A set of benchmarking kernels and application codes are used to validate the accuracy, utility, usability, and cost-effectiveness of the performance prediction framework. The use of the framework for selecting appropriate compiler directives and for application performance debugging is demonstrated. Keywords: Performance prediction, HPF/Fortran 90D application development, …

Run-Time And Compile-Time Support For Adaptive Irregular Problems, Shamik D. Sharma, Ravi Ponnusamy, Bongki Moon, Yuan-Shin Hwang

Northeast Parallel Architecture Center

In adaptive irregular problems the data arrays are accessed via indirection arrays, and data access patterns change during computation. Implementing such problems on distributed memory machines requires support for dynamic data partitioning, efficient preprocessing and fast data migration. This research presents efficient runtime primitives for such problems. This new set of primitives is part of the CHAOS library. It subsumes the previous PARTI library which targeted only static irregular problems. To demonstrate the efficacy of the runtime support, two real adaptive irregular applications have been parallelized using CHAOS primitives: a molecular dynamics code (CHARMM) and a particle-in-cell code (DSMC). The …

Compiling Fortran 90d/Hpf For Distributed Memory Mimd Computers, Zeki Bozkus, Alok Choudhary, Geoffrey C. Fox, Tomasz Haupt

Northeast Parallel Architecture Center

This paper describes the design of the Fortran90D/HPF compiler, a source-to-source parallel compiler for distributed memory systems being developed at Syracuse University. Fortran 90D/HPF is a data parallel language with special directives to specify data alignment and distributions. A systematic methodology to process distribution directives of Fortran 90D/HPF is presented. Furthermore, techniques for data and computation partitioning, communication detection and generation, and the run-time support for the compiler are discussed. Finally, initial performance results for the compiler are presented. We believe that the methodology to process data distribution, computation partitioning, communication system design and the overall compiler design can be …

Mapping Algorithms And Software Environment For Data Parallel, Nikos Chrisochoides, Elias Houstis, John Rice

Northeast Parallel Architecture Center

We consider computations associated with data parallel iterative solvers used for the numerical solution of Partial Differential Equations (PDEs). The mapping of such computations into load balanced tasks requiring minimum synchronization and communication is a difficult combinatorial optimization problem. Its optimal solution is essential for the efficient parallel processing of PDE computations. Determining data mappings that optimize a number of criteria, like workload balance, synchronization and local communication, often involves the solution of an NP-Complete problem. Although data mapping algorithms have been known for a few years there is lack of qualitative and quantitative comparisons based on the actual performance …

Runtime Array Redistribution In Hpf Programs, Rajeev Thakur, Alok Choudhary, Geoffrey C. Fox

Northeast Parallel Architecture Center

This paper describes efficient algorithms for runtime array redistribution in HPF programs. We consider block(m) to cyclic, cyclic to block(m) and the general cyclic(x) to cyclic(y) type redistributions. We initially describe algorithms for one-dimensional arrays and then extend the methodology to multidimensional arrays. The algorithms are practical enough to be easily implemented in the runtime library of an HPF compiler and can also be directly used in application programs requiring redistribution. Performance results on the Intel Paragon are discussed.

Analysis Of Random Number Generators Using Monte Carlo Simulation, Paul D. Coddington

Northeast Parallel Architecture Center

Monte Carlo simulation is one of the main applications involving the use of random number generators. It is also one of the best methods of testing the randomness properties of such generators, by comparing results of simulations using different generators with each other, or with analytic results. Here we compare the performance of some popular random number generators by high precision Monte Carlo simulation of the 2-d Ising model, for which exact results are known, using the Metropolis, Swendsen-Wang, and Wolff Monte Carlo algorithms. Many widely used generators that perform well in standard statistical tests are shown to fail these …

Supporting Irregular Distributions In Fortran 90d/Hpf Compilers, Ravi Ponnusamy, Yuan-Shin Hwang, Raja Das, Joel Saltz

Northeast Parallel Architecture Center

This paper presents methods that make it possible to efficiently support irregular problems using data parallel languages. The approach involves the use of a portable, compiler-independent, runtime support library called CHAOS. The CHAOS runtime support library contains procedures that (1) support static and dynamic distributed array partitioning, (2) partition loop iterations and indirection arrays, (3) remap arrays from one distribution to another, and (4) carry out index translation, buffer allocation and communication schedule generation. The CHAOS runtime procedures are used by a prototype Fortran 90D compiler as runtime support for irregular problems. This paper also presents performance results of compiler-generated …