Digital Commons Network^™

The Computation Of Supersonic Combustor Flows Using Multi-Computers, Bruce M. Mcmillin, Eric Jui-Lin Lu, Larry Reeves

Computer Science Technical Reports

An explicit computational fluid dynamics (CFD) computer code with parallel processing capability has been developed for the purpose of simulating internal high-speed reacting flows. The code solves the three-dimensional Navier-Stokes equations for compressible flows. The CFD code can be executed on either sequential (single processor) computers or multi-computers (multiple processor machines with distributed memory and message passing between processors). The parallel implementation involves homogeneous domain decomposition between processors with message passing needed only between neighbor processors. The code is validated for a compression ramp, an expansion ramp, a viscous flat plate, and a viscous flat plate with wall injection. These …

Emergent Control And Planning In An Autonomous Vehicle, Lisa Meeden, Gary Mcgraw, Doug Blank

Computer Science Faculty Research and Scholarship

No abstract provided.

A Probabilistic Analysis Of A Locality Maintaining Load Balancing Algorithm, Kishan Mehrotra, Sanjay Ranka, Jhy-Chun Wang

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

This paper presents a simple load balancing algorithm and its probabilistic analysis. Unlike most of the previous load balancing algorithms, this algorithm maintains locality. We show that the cost of this load balancing algorithm is small for practical situations and discuss some interesting applications for data remapping.

Static And Runtime Scheduling Of Unstructured Communication, Sanjay Ranka, Jyu-Chun Wang

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

With the advent of new routing methods, the distance to which a message is sent is becoming relatively less and less important. Thus assuming no link contention, permutation seems to be an efficient collective communication primitive. All-to-many communication is required for solving a large class of irregular and loosely synchronous problems on distributed memory MIMD machines. In this paper we present several algorithms for decomposing all-to-many personalized communication into a set of disjoint partial permutations. These partial permutations avoid node contention and/or link contention. We discuss several algorithms and study their effectiveness both from the view of static scheduling as …

Solving The Region Growing Problem On The Connection Machine, Nawal Copty, Sanjay Ranka, Geoffrey C. Fox, Ravi Shankar

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

This paper presents a parallel algorithm for solving the region growing problem based on the split and merge approach. The algorithm was implemented on the CM-2 and the CM-5 in the data parallel and message passing models. The performance of these implementations is examined and compared.

Architectural Support For High-Performance Distributed Computing, Jongbaek Park, Salim Hariri

Electrical Engineering and Computer Science - All Scholarship

The emergence of high speed networks and the proliferation of high performance workstations have attracted a lot of interest in workstation-based distributed computing. Current trend in local area networks is toward higher communication bandwidth as we progress from Ethernet networks that operate at 10 Mbit/sec to higher speed networks that can operate in Gbit/sec range. Also, current workstations are capable of delivering tens and hundreds of Megaflops of computing power. By using a cluster of such high-performance workstations and the high-speed networks, a high-performance distributed computing environment could be built in cost-effective manner as an alternative of supercomputing platform. However, …

Runtime Compilation Techniques For Data Partitioning And Communication Schedule Reuse, Ravi Ponnusamy, Joel Saltz, Alok Choudhary

Northeast Parallel Architecture Center

In this paper, we describe two new ideas by which HPF compiler can deal with irregular computations effectively. The first mechanism invokes a user specified mapping procedure via a set of compiler directives. The directives allow the user to use program arrays to describe graph connectivity, spatial location of army elements and computational load. The second is a simple conservative method that in many cases enables a compiler to recognize that it is possible to reuse previously computed results from inspectors (e.g. communication schedules, loop iteration partitions, information that associates off-processor data copies with on-processor buffer locations). We present performance …

Fast Mapping And Remapping Algorithms For Irregular And Adaptive Problems, Chao Wei Ou, Sanjay Ranka, Geoffrey C. Fox

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

This paper describes the performance of locality-based mapping and remapping partitioners for unstructured grids. We show that the algorithm produces good mappings at a relatively low cost and can be easily parallelized. Further, the algorithm can provide remapping for incremental problems at a fraction of the total cost.

A Model For Syntactic Control Of Interference, Peter W. O'Hearn

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

Two imperative programming language phrases interfere when one writes to a storage variable that the other reads from or writes to. Reynolds has described an elegant linguistic approach to controlling interference in which a refinement of typed λ-calculus is used to limit sharing of storage variables; in particular, different identifiers are required never to interfere. This paper examines semantic foundations of the approach. We describe a category that has (an abstraction of) interference information built into all objects and maps. This information is used to define a “tensor” product whose components are required never to interfere. Environments are defined using …

Distributed Scheduling Of Unstructured Collective Communication On The Cm-5 (1993), Jyu-Chun Wang, Tseng-Hui Lin, Sanjay Ranka

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

Parallelization of many irregular applications results in unstructured collective communication. In this paper we present a distributed algorithm for scheduling such communication on parallel machines. We describe the performance of this algorithm on the CM-5 and show that the scheduling algorithm has very small overhead and gives a significant improvement over naive methods.

Ccis Networking - January 1993, Nova University

CCIS Networking / SCIS Networking magazines

No abstract provided.

Georg Cantor And The Battle For Transfinite Set Theory, Joseph Dauben

ACMS Journal 2004

Georg Cantor is well known as the founder of transfinite set theory. Equally celebrated, however, are the obstacles he faced in trying to win acceptance for his seemingly unorthodox views, his acrimonious differences with Leopold Kronecker and his unfortunate but progressively debilitating nervous breakdowns that some authors have linked directly to his many problems with set theory. Above all, Cantor's justification of set theory was all the more urgent because of Kronecker's critical denunciation of Cantor's mathematics. In tracing the evolution of Cantorian set theory, it is necessary to examine the opposition it met, and evaluate the technical, philosophical, psychological, …

Software And Hardware Support For Workstation-Based, Salim Hariri, Manish Parashar, Jongbaek Park

Electrical Engineering and Computer Science - All Scholarship

The proliferation of high performance workstations and the emergence of high speed networks have attracted a lot of interest in workstation-based supercomputing. We project that workstation-based environments with supercomputing capabilities will be available in the not-so-distant future. However a number of hardware and software issues have to be resolved before the full potential of these workstation-based supercomputing environments can be exploited. The presented research has two main objectives: (1) to investigate the limitations of communications techniques used in current workstation-based systems and to identify a set of requirements that must be satisfied to achieve workstation-based supercomputing; (2) to use these …

On The Edge Arboricity Of A Random Graph, P. A. Catlin, Zhi-Hong Chen, E. M. Palmer

Scholarship and Professional Work - LAS

No abstract provided.

Integrated Computer Controlled Sensor Monitor, Tariq Hafeez Malik

Theses : Honours

This research has developed an Integrated Computer Controlled Sensor Monitor (ICCSM) environment, to monitor and analyse alarm events associated with sensors, including an interface between a PC and a number of detectors. Such an environment will help the security industry analyse the factors causing false alarms at particular locations. The ICCSM environment monitors, and records, alarm data. Knowing exactly which sensor has been activated, and its location, is of paramount importance to the effective deployment of response forces and making the identification of causes of spurious alarms easier. The lCCSM environment is a combination of software and general purpose hardware, …

Clock Partitioning For Testability, Kent L. Einspahr, Sharad C. Seth, Vishwani D. Agrawal

School of Computing: Conference and Workshop Papers

An implementation of a design for testability model for sequential circuits is presented. The flip-flops in a sequential circuit are partitioned to reduce the number of cycles and the path lengths in each partition, thereby reducing the complexity of test generation. The implementation includes a Podem-based test generator. Preliminary results using the Contest sequential test generator are presented.

A-Hohfeld: A Language For Robust Structural Representation Of Knowledge In The Legal Domain To Build Interpretation-Assistance Expert Systems, Layman E. Allen, Charles S. Saxon

Book Chapters

The A-Hohfeld language is presented as a set of definitions; it can be used to precisely express legal norms. The usefulness of the AHohfeld language is illustrated in articulating 2560 alternative structural interpretations of the four-sentence 1982 Library Regulations of Imperial College and constructing an interpretation-assistance legal expert system for these regulations by means of the general-purpose Interpretation-Assistance legal expert system builder called MINT. The logical basis for A-Hohfeld is included as an appendix.

So Far (Schematically) Yet So Near (Semantically), Amit P. Sheth, Vipul Kashyap

Kno.e.sis Publications

In a multidatabase system, schematic conflicts between two objects are usually of interest only when the objects have some semantic affinity. In this paper we try to reconcile the two perspectives. We first define the concept of semantic proximity and provide a semantic taxonomy. We then enumerate and classify the schematic and data conflicts. We discuss possible semantic similarities between two objects that have various types of schematic and data conflicts. Issues of uncertain information and inconsistent information are also addressed.

On Matching Ann Structure To Problem Domain Structure, George G. Lendaris, Martin Zwick, Karl Mathia

Complex Systems Faculty Publications and Presentations

To achieve reduced training time and improved generalization with artificial neural networks (ANN, or NN), it is important to use a reduced complexity NN structure. A "problem" is defined by constraints among the variables describing it. If knowledge about these constraints could be obtained a priori, this could be used to reduce the complexity of the ANN before training it. Systems theory literature contains methods for determining and representing structural aspects of constrained data (these methods are herein called GSM, general systems method). The suggestion here is to use the GSM model of the given data as a pattern for …

Asymptotically Tight Bounds For Performing Bmmc Permutations On Parallel Disk Systems, Thomas H. Cormen, Leonard F. Wisniewski

Computer Science Technical Reports

No abstract provided.

Development Of A Hypermedia Database For The Elementary Classroom, Jane Pattison Brown

All Graduate Projects

A hypermedia database including selected flora and fauna in Kittitas County, Washington, was developed using HyperCard software for researching information about 400+ species. students had the opportunity to use the database in school libraries and in the author's fifth-grade classroom. The database cards accessed videodisc images where available. On the basis of limited study to date, it appears that when studying the environment, student learning was enhanced by the use of database material created by the author.

Ensuring The Satisfaction Of A Temporal Specification At Run-Time, Grace Tsai, Matt Insall, Bruce M. Mcmillin

Computer Science Technical Reports

This paper presents an approach to operationally evaluate a temporal specification in a distributed computing environment. First, an algorithm Compute History is proposed to allow every distributed processor to collect events executed by itself and by other processors, and to order the collected events by causality. This algorithm employs neither monitors nor a global clock to order collected events of a processor. These collected events of a processor form an execution history of a distributed computation, and they represent behaviors of all the processors during execution. Next, the semantics of operational evaluation of a temporal assertion is presented. The evaluation …

The N-Body Problem: Distributed System Load Balancing And Performance Evaluation, Vasudha Govindan, Mark A. Franklin

All Computer Science and Engineering Research

In this paper, the N-body simulation problem is considered, its parallel implementation described, its execution time performance is modeled and compared with measured results, and two alternative load balancing algorithms for enhancing performance investigated. Parallel N-body techniques are widely applied in various fields and possess characteristics that challenge the computation and communication capabilities of parallel computing systems and are therefore good candidates for use as parallel benchmarks. Performance models may be used to estimate the performance of an algorithm on a given system, identify performance bottlenecks and study the performance implications of several algorithm are system enhancements. In this paper, …

Approximation Algorithms For Configuring Hierarchical Nonblocking Communication Networks, J. Andrew Fingerhut

All Computer Science and Engineering Research

A framework is given for specifying nonblocking traffic limits in a connection-oriented communications network. In this framework, connections may be point-to-point or mutlipoint, and the data rates may vary from one connection to another. The traffic limits may be "flat", or they may also be hierarchical, representing communities of interest within the network that have higher traffic among themselves than with the rest of the network. The communication networks are constructed from switches (or nodes) and trunks, which connect pairs of switches. This framework is intended to model Asynchronous Transfer Mode (ATM) networks and traffic. We present a way of …

Dynamic Reconfiguration With I/O Abstraction, Bala Swaminathan, Kenneth J. Goldman

All Computer Science and Engineering Research

Dynamic reconfiguration is explored in the context of I/O abstraction, a new programming model that defines the communication structure of a system in terms of connections among well-defined data interfaces for the modules in the system. The properties of I/O abstraction, particularly the clear separation of computation from communication and the availability of a module's state information, help simplify the reconfiguration strategy. Both logical and physical reconfiguration are discussed, with an emphasis on a new module migration mechanism that (1) takes advantage of the underlying I/O abstraction model, (2) avoids the expense and complication of state extraction techniques, (3) minimizes …

The Dim System: Turn-Taking In Dyadic Telephone Dialogues, Umesh Berry, Anne Johnstone

All Computer Science and Engineering Research

The analysis of human conversations has revealed that the design of interfaces using spoken dialogue must differ radically from those using written communication. Such characteristics as prosody, confirmations, echoes, and other speech phenomena must be considered. This work is a step in that direction. Prosodic, syntactic and semantic information from actual human dialogues has been used to build a turn-taking model empirically for dydadic telephone dialogues. The ability to predict completion of turns has been the biggest motivating factor in the development of this model. The design and evaluation of the model are presented in this report.

The Dim System: Woz Simulation Results - Phase Ii, Anne Johnstone, Umesh Berry, Tina Nguyen

All Computer Science and Engineering Research

We report an experiment designed to compare human-human spoken dialogues with human-computer spoken dialogue. Our primary purpose was to collect data on the kinds of protocols that were used to control the interaction. Three groups of 12 subjects each were asked to complete tasks over the phone. These tasks involved the use of custom-calling features such as call-forwarding and speed-dialing. The experimental procedure was a new variation on the Wizard of Oz (WOZ) technique that allowed much clearer comparisons to be made between human-human and human-computer interactions. Subjects in the Operator Group were told they were talking to a human …

An Object Oriented Preemptive Multitasking Kernel, Lee Gene Shipman

Masters Theses

“This paper describes a preemptive multitasking kernel designed and coded using C++ using an object oriented paradigm. The kernel design, while implemented on an Intel 80386 based IBM PC running MS-DOS 4.01, can be ported to any platform, rewriting only the low level, hardware specific code.

The kernel, in application framework form, enables the applications developer to create real-time multitasking applications. This can be done in a systematic way by capitalizing on the power of object oriented program development.

A simulation was created to verify the correctness of the kernel against a traditional non-multitasking approach. This simulation provides the proof …

The Programmers' Playground: I/O Abstraction For Heterogeneous Distributed Systems, Kenneth J. Goldman, Michael D. Anderson, Bala Swaminathan

All Computer Science and Engineering Research

I/O abstraction is offered as a new high-level approach to interprocess communication. Functional components of a concurrent system are written as encapsulated modules that act upon local data structures, some of which may be published for external use. Relationships among modules are specified by logical connections among their published data structures. Whenever a module updates published data, I/O takes place implicitly according to the configuration of logical connections. The Programmer's Playground, a software library and run-time system supporting I/O abstraction, is described. Design goals include high-level communication among programs written in multiple programming languages and the uniform treatment of discrete …

A Methodology For Developing High Performance Computing Models: Storm-Scale Weather Prediction, Nikos Chrisochoides, Kelvin Droegemeier, Geoffrey C. Fox, Kim Mills, Ming Xue

Northeast Parallel Architecture Center

A methodology for developing future generations of a storm-scale weather prediction model for Massively Parallel Processing is described. The forecast model is the Advanced Regional Prediction System (ARPS), a three-dimensional, fully compressible, non-hydrostatic predictive model. In the short term, the computational goals include developing a portable, scalable model for distributed memory SIMD and MIMD architectures, while preserving a high degree of modularity to support rapid design and validation, maintainability, educational goals and operational testing. Longer term computational goals include a parallel adaptive mesh refinement scheme. A FortranD/High Performance Fortran version of the ARPS provides portability in the current version of …