Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Computer Sciences

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 60001 - 60030 of 63085

Full-Text Articles in Entire DC Network

Cell Tracking Using A Distributed Algorithm For 3d Image Segmentation, Vikas Awasthi, Keith W. Doolittle, Guru Parulkar, James G. Mcnally Jan 1994

Cell Tracking Using A Distributed Algorithm For 3d Image Segmentation, Vikas Awasthi, Keith W. Doolittle, Guru Parulkar, James G. Mcnally

All Computer Science and Engineering Research

We have developed and tested an automated method for simultaneous 3D tracking of numerous, flourescently-tagged cells. The procedure uses multiple thresholding to segment individual cells at a starting timepoint, and then iteratively applies a template-matching algorithm to locate a particular cell's position at subsequent time points. To speed up the method, we have developed a distributed implementation in which template matching is carried out in parallel on several different server machines. The distributed implementation showed a monotonic decrease in response time with increasing number of servers (up to 15 tested), demonstrating that the tracking algorithm is well suited to parallelization, …

Go to article

Efficient Quality Of Service Support In Multimedia Computer Operating Systems, Raman Gopalakrishna, Guru M. Parulkar Jan 1994

Efficient Quality Of Service Support In Multimedia Computer Operating Systems, Raman Gopalakrishna, Guru M. Parulkar

All Computer Science and Engineering Research

This report describes our approach towards providing quality of service (QoS) guarantees for network communication within the endsystems to support multimedia applications. We first address the problem of QoS specification by identifying a set of application classes and their QoS parameters that cover the communication requirements of most applications. We then describe the QoS mapping problem, and show how requirements for resources (such as the CPU, the network interface adaptor and network connections) can be automatically derived from the application QoS parameters. We then deal with the QoS enforcement issue in which we describe techniques for scheduling protocol processing threads …

Go to article

Morphing Binary Trees, John Hershberger, Subhash Suri Jan 1994

Morphing Binary Trees, John Hershberger, Subhash Suri

All Computer Science and Engineering Research

We investigate the problem of transforming one binary tree into another by rotatoins, subject to certain weight ocnstraints on the nodes of the trees. These constraints arise in the problem of "morphing" one simple polygon to another simple polygon by continuous deformatinos (translations and scalings) that preserve the turn angles and the simplicity of the polygon; the two polygons must have the same sequence of turn angles. Our main theorem is that two arbitrary n-leaf binary trees satisfying our weight constraint can be morphed into each other with O(n log n) rotations. Furthermore, we also present an O(n log n) …

Go to article

Distributed Data Layout, Scheduling And Playout Control In A Large Scale Multimedia Storage Server, Milind M. Buddhikot, Guru Parulkar Jan 1994

Distributed Data Layout, Scheduling And Playout Control In A Large Scale Multimedia Storage Server, Milind M. Buddhikot, Guru Parulkar

All Computer Science and Engineering Research

No abstract provided.

Go to article

Boxgraph: A Two-Dimensional Visual Computation Model, Takayuki Dan Kimura, Timothy B. Brown Jan 1994

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 …

Go to article

Learning And Teaching Of Boolean And Geometric Classes, H. David Mathias Jan 1994

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 …

Go to article

Proposal For Research Distribution Of Gigabit Network Technology, Jonathan Turner Jan 1994

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.

Go to article

Design Of An Application Development Toolkit For Hpf/Fortran 90d, Manish Parashar, Salim Hariri, Tomasz Haupt, Geoffrey C. Fox Jan 1994

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 …

Go to article

Interpreting The Performance Of Hpf/Fortran 90d, Manish Parashar, Salim Hariri, Tomasz Haupt, Geoffrey C. Fox Jan 1994

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, …

Go to article

Run-Time And Compile-Time Support For Adaptive Irregular Problems, Shamik D. Sharma, Ravi Ponnusamy, Bongki Moon, Yuan-Shin Hwang Jan 1994

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 …

Go to article

Compiling Fortran 90d/Hpf For Distributed Memory Mimd Computers, Zeki Bozkus, Alok Choudhary, Geoffrey C. Fox, Tomasz Haupt Jan 1994

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 …

Go to article

Mapping Algorithms And Software Environment For Data Parallel, Nikos Chrisochoides, Elias Houstis, John Rice Jan 1994

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 …

Go to article

Runtime Array Redistribution In Hpf Programs, Rajeev Thakur, Alok Choudhary, Geoffrey C. Fox Jan 1994

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.

Go to article

Analysis Of Random Number Generators Using Monte Carlo Simulation, Paul D. Coddington Jan 1994

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 …

Go to article

Supporting Irregular Distributions In Fortran 90d/Hpf Compilers, Ravi Ponnusamy, Yuan-Shin Hwang, Raja Das, Joel Saltz Jan 1994

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 …

Go to article

The Design And Evolution Of Zipcode, Anthony Skjellum, Steven G. Smith, Nathan E. Doss, Alvin Leung Jan 1994

The Design And Evolution Of Zipcode, Anthony Skjellum, Steven G. Smith, Nathan E. Doss, Alvin Leung

Northeast Parallel Architecture Center

Zipcode is a message-passing and process-management system that was designed for multicomputers and homogeneous networks of computers in order to support libraries and large-scale multicomputer software. The system has evolved significantly over the last five years, based on our experiences and identified needs. Features of Zipcode that were originally unique to it, were its simultaneous support of static process groups, communication contexts, and virtual topologies, forming the "mailer" data structure. Point-to-point and collective operations reference the underlying group, and use contexts to avoid mixing up messages. Recently, we have added "gather-send" and "receive-scatter" semantics, based on persistent Zipcode "invoices," both …

Go to article

A Communication System For High-Performance Distributed Computing, Salim Hariri, Jongbaek Park, Manish Parashar, Geoffrey C. Fox Jan 1994

A Communication System For High-Performance Distributed Computing, Salim Hariri, Jongbaek Park, Manish Parashar, Geoffrey C. Fox

Northeast Parallel Architecture Center

With the current advances in computer and networking technology coupled with the availability of software tools for parallel and distributed computing, there has been increased interests in high-performance distributed computing (HPDC). We envision that HPDC environments with supercomputing capabilities will be available in the near future. However, a number of issues have to be resolved before future network-based applications can exploit fully the potential of HPDC environment. In this paper, we present an architecture of a high-speed local area network and a communication system that provides HPDC applications with high bandwidth and low latency. We also characterize the message-passing primitives …

Go to article

Developing Interactive Pvm-Based Parallel Programs On Distributed Computing Systems Within Avs Framework, Gang Cheng, Geoffrey C. Fox, Kim Mills, Marek Podgorny Jan 1994

Developing Interactive Pvm-Based Parallel Programs On Distributed Computing Systems Within Avs Framework, Gang Cheng, Geoffrey C. Fox, Kim Mills, Marek Podgorny

Northeast Parallel Architecture Center

We discuss techniques in developing interactive Parallel Virtual Machine (PVM) concurrent programs on distributed systems under AVS framework. Using a stock option price modeling application as a case study, we demonstrate a simple, effective and modular approach to coupling network-based concurrent modules into an interactive remote visualization environment. A prototype simulation on-demand system is developed, in which parallel option pricing models locally implemented on two distributed systems, an Ethernet-connected IBM SP1 and a FDDI-based GIGswitch-connected DEC Alpha farm, are coupled with an interactive graphical user interface over a ATM-based wide area network. This integrated networking/visualization framework allows one to use …

Go to article

Involvement Of Industry In The National High Performance Computing And Communication Enterprise, Geoffrey C. Fox Jan 1994

Involvement Of Industry In The National High Performance Computing And Communication Enterprise, Geoffrey C. Fox

Northeast Parallel Architecture Center

We discuss aspects of a national computer science agenda for High Performance Computing and Communications (HPCC). We agree with the general direction and emphasis of the current program. In particular, the strong experimental component and linkage of applications with computer science should be continued. We recommend accelerating the emphasis on "national challenges " with more applications and technologies from the information, as compared to simulation areas. We suggest modifying the grand challenge concept to complement the current teaming of particular computer science and applications researchers. We would emphasize better linking of each application group to the entire (inter) national computer …

Go to article

A Study Of Software Development For High Performance Computing, Manish Parashar, Salim Hariri, Tomasz Haupt, Geoffrey C. Fox Jan 1994

A Study Of Software Development For High Performance Computing, Manish Parashar, Salim Hariri, Tomasz Haupt, Geoffrey C. Fox

Northeast Parallel Architecture Center

Software development in a High Performance Computing (HPC) environment is non-trivial and requires a thorough understanding of the application and the architecture. The objective of this paper is to study the software development process in a high performance computing environment and to outline the stages typically encountered in this process. Support required at each stage is also highlighted. The modeling of stock option pricing is used as a running example in the study.

Go to article

Developing Modular Application Builders To Exploit Mimd Parallel Resources, C. Thornborrow, C. Faigle Jan 1994

Developing Modular Application Builders To Exploit Mimd Parallel Resources, C. Thornborrow, C. Faigle

Northeast Parallel Architecture Center

Modular application builders (MABs), such as AVS and Iris Explorer[6, 7] are increasingly being used in the visualisation community. Such systems can already place compute intensive modules on supercomputers in order to utilise their power. This paper details two major projects at EPCC which attempted to fully integrate the MAB concept with a distributed memory MIMD (DM-MIMD) environment. The work presented was driven by two goals, efficient use of the resource and ease of use by programmer and end user. We present a model of MABs and describe the major problems faced, giving solutions to them through two case studies.

Go to article

Applications And Enabling Technology For Nynet Upstate Corridor, Salim Hariri, Geoffrey C. Fox Jan 1994

Applications And Enabling Technology For Nynet Upstate Corridor, Salim Hariri, Geoffrey C. Fox

Northeast Parallel Architecture Center

Current advances in telecommunication and computing will have significant impact on the proliferation of high performance computing and communication (HPCC) applications. With these emerging technologies, it is feasible to run parallel and distributed applications across a high speed wide area network which was not possible a few years ago; the high latency and low bandwidth were the main bottlenecks for the wide area network-based computing. This has lead to the deployment of several high speed networks across the country (eg. NYNET). In this report, we describe some of the HPCC applications and our experiences and lessons learned from running them …

Go to article

The Virtual Computing Environment, Philip Rousselle, Paul Tymann, Salim Hariri, Geoffrey C. Fox Jan 1994

The Virtual Computing Environment, Philip Rousselle, Paul Tymann, Salim Hariri, Geoffrey C. Fox

Northeast Parallel Architecture Center

A network of supercomputers and high-performance workstations appears to be the only reasonable way to provide adequate computing resources for the Grand Challenge problems of the next century. Such a collection of computers and supporting software environments is called a virtual computing environment (VCE). This paper describes the motivation and goals of the VCE project, followed by a description of the system. The paper concentrates on the runtime aspects of the VCE, and concludes with a discussion of a small prototype system that has been built using the Isis distributed toolkit.

Go to article

Data Access Reorganizations In Compiling Out-Of-Core Data Parallel Programs On Distributed Memory Machines, Rajesh Bordawekar, Alok Choudhary, Rajeev Thakur Jan 1994

Data Access Reorganizations In Compiling Out-Of-Core Data Parallel Programs On Distributed Memory Machines, Rajesh Bordawekar, Alok Choudhary, Rajeev Thakur

Electrical Engineering and Computer Science - All Scholarship

This paper describes techniques for translating out-of-core programs written in a data parallel language like HPF to message passing node programs with explicit parallel I/O. We describe the basic compilation model and various steps involved in the compilation. The compilation process is explained with the help of an out-of-core matrix multiplication program. We first discuss how an out-of-core program can be translated by extending the method used for translating in-core programs. We demonstrate that straightforward extension of in-core compiler does not work for out-of-core programs. We then describe how the compiler can optimize the code by (1) estimating the I/O …

Go to article

Passion: Parallel And Scalable Software For Input-Output, Alok Choudhary, Rajesh Bordawekar, Michael Harry, Rakesh Krishnaiyer Jan 1994

Passion: Parallel And Scalable Software For Input-Output, Alok Choudhary, Rajesh Bordawekar, Michael Harry, Rakesh Krishnaiyer

Electrical Engineering and Computer Science - All Scholarship

We are developing a software system called PASSION: Parallel And Scalable Software for Input-Output which provides software support for high performance parallel I/O. PASSION provides support at the language, compiler, runtime as well as file system level. PASSION provides runtime procedures for parallel access to files (read/write), as well as for out-of-core computations. These routines can either be used together with a compiler to translate out-of-core data parallel programs written in a language like HPF, or used directly by application programmers. A number of optimizations such as Two-Phase Access, Data Sieving, Data Prefetching and Data Reuse have been incorporated in …

Go to article

Relationship Between Information System Project Characteristics And Project Management Activities: An Empirical Investigation, Vijay V. Raghavan, Deepak Khazanchi, Joyce L. Webster Jan 1994

Relationship Between Information System Project Characteristics And Project Management Activities: An Empirical Investigation, Vijay V. Raghavan, Deepak Khazanchi, Joyce L. Webster

Information Systems and Quantitative Analysis Faculty Publications

The activities of a project manager in overseeing the development of a software system are many and varied. Not all such activities are performed in managing every project. If so, a natural ensuing question is whether project managers adapt their managerial functions to the projects being managed. Prior research suggests that they do adapt, and that project characteristics may be the factors determining this adaptation. This assertion is investigated by considering three characteristics of a project (size, type, and environment) and investigating their association with four traditionally recognized management functions (planning, organizing, controlling, and motivating). Results indicate that project managers …

Go to article

An ‘Events’ Model For Information Aggregation, Douglas Havelka, Deepak Khazanchi Jan 1994

An ‘Events’ Model For Information Aggregation, Douglas Havelka, Deepak Khazanchi

Information Systems and Quantitative Analysis Faculty Publications

Aggregation is one of the key characteristics of information delivered by "information systems." It is important because the ability to design effective support systems depends to a great extent upon the degree of flexibility with regards to information aggregation that can be incorporated in the system. This paper sets forth a conceptual model of information aggregation based on the events theory of accounting. The model suggests that aggregation should be considered as a two-dimensional concept, comprising a temporal and sectional dimension. The two axes are further delineated in the form of "levels of summation" based on specified "events" of aggregation. …

Go to article

Vic*: A Preprocessor For Virtual-Memory C*, Thomas H. Cormen, Alex Colvin Jan 1994

Vic*: A Preprocessor For Virtual-Memory C*, Thomas H. Cormen, Alex Colvin

Computer Science Technical Reports

This paper describes the functionality of ViC*, a compiler-like preprocessor for out-of-core C*. The input to ViC* is a C* program but with certain shapes declared \verb`outofcore`, which means that all parallel variables of these shapes reside on disk. The output is a standard C* program with the appropriate I/O and library calls added for efficient access to out-of-core parallel variables.

Go to article

Visualisation Of Inshore Marine Water Depth Data, Karen Powell Jan 1994

Visualisation Of Inshore Marine Water Depth Data, Karen Powell

Theses : Honours

The literature review performed as part of this Project concentrated on two objectives. The first objective was the identification of techniques applicable to the visualisation of the inshore marine water depth data obtained from the Department of Marine & Harbours (M&H). The second objective involved examining how colour is best used within data visualisation. The experimentation investigated a simple method for interpreting movement between depth surveys undertaken by M&H. Although it achieved the objective of creating a longer and smoother animation, it was concluded that the movement of the harbour floor was not accurately represented. The Project applied an optical …

Go to article

Visualizing Electrostatic Phenomena Using Mathematica, Eric Mayes Jan 1994

Visualizing Electrostatic Phenomena Using Mathematica, Eric Mayes

Journal of the Arkansas Academy of Science

A set of packages for visualizing electrostatic phenomena was developed using Mathematica as a programming language. These packages allow users to plot potential fields, equipotential lines, 2-D and 3-D vector fields in order to gain a visual understanding of electrostatic charges. They would be useful in accompanying undergraduate physics labs pertaining to electrostatics, as they would enable students to connect experiment with mathematics through open-ended visual exploration

Go to article

First Prev Next Last