Digital Commons Network^™

1.0, Yolanda Jones

E-lert

No abstract provided.

Characterizing Parallel File-Access Patterns On A Large-Scale Multiprocessor, Apratim Purakayastha, Carla Schlatter Ellis, David Kotz, Nils Nieuwejaar, Michael Best

Dartmouth Scholarship

Rapid increases in the computational speeds of multiprocessors have not been matched by corresponding performance enhancements in the I/O subsystem. To satisfy the large and growing I/O requirements of some parallel scientific applications, we need parallel file systems that can provide high-bandwidth and high-volume data transfer between the I/O subsystem and thousands of processors. \par Design of such high-performance parallel file systems depends on a thorough grasp of the expected workload. So far there have been no comprehensive usage studies of multiprocessor file systems. Our CHARISMA project intends to fill this void. The first results from our study involve an …

Logging Subsystem Performance: Model And Evaluation, Thomas K. Clark

Dissertations and Theses

Transaction logging is an integral part of ensuring proper transformation of data from one state to another in modern data management. Because of this, the throughput of the logging subsystem can be critical to the throughput of an application. The purpose of this research is to break the log bottleneck at minimum cost.

We first present a model for evaluating a logging subsystem, where a logging subsystem is made up of a log device, a log backup device, and the interconnect algorithm between the two, which we term the log backup method. Included in the logging model is a set …

A Vlsi Implementation Of A Parallel, Self-Organizing Learning Model, Tony R. Martinez, George L. Rudolph, Linton G. Salmon, Matthew G. Stout

Faculty Publications

This paper presents a VLSI implementation of the Priority Adaptive Self-organizing Concurrent System (PASOCS) learning model that is built using a multi-chip module (MCM) substrate. Many current hardware implementations of neural network learning models are direct implementations of classical neural network structures - a large number of sample computing nodes connected by a dense number of weighted links. PASOCS is one of a class of ASOCS (Adaptive Self-Organizing Concurrent System) connectionist models whose overall goal is the same as classical neural networks models, but whose functional mechanisms differ significantly. This model has potential application in areas such as pattern recognition, …

Cognitive Engineering For Intelligent Man-Machine Systems, Erika Rogers

Computer Science and Software Engineering

This paper discusses a methodology for cognitive engineering which provides a framework for the cognitive studies→intelligent system development→cognitive studies cycle. The methodology has been developed to address the problem of providing knowledge-based cooperative assistance in visual reasoning tasks, and is discussed in terms of its impact on three different application domains: diagnostic radiology, geographical information systems, and tele-assisted robot supervision.

The "Infoharness" Information Integration Platform, Leon Shklar, Satish Thatte, Howard Marcus, Amit P. Sheth

Kno.e.sis Publications

The "InfoHarness" information integration platform, tools, and services being developed at Bellcore are aimed at providing integrated and rapid access to huge amounts of heterogeneous information independent of the type, representation, and location of information. InfoHarness provides advanced search and browsing capabilities without imposing the burden of restructuring, reformatting or relocating information on information suppliers or creators. This is achieved through object-oriented encapsulation of information and the associated meta-information (e.g., type, location, access rights, owner, creation date, etc.). The meta-information extraction methods ensure rapid and largely automatic creation of information repositories. A gateway that supports access to InfoHarness repositories from …

Hypergraph Partitioning Algorithms, Tom Leighton, Fillia Makedon, Spyros Tragoudas

Computer Science Technical Reports

We present the first polynomial time approximation algorithms for the balanced hypergraph partitioning problem. The approximations are within polylogarithmic factors of the optimal solutions. The choice of algorithm involves a time complexity/approximation bound tradeoff. We employ a two step methodology. First we approximate the flux of the input hypergraph. This involves an approximate solution to a concurrent flow problem on the hypergraph. In the second step we use the approximate flux to obtain approximations for the balanced bipartitioning problem. Our results extend the approximation algorithms by Leighton-Rao on graphs to hypergraphs. We also give the first polylogarithmic times optimal approximation …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 10, Number 8, October 1994, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

An eight page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Spiders: A New User Interface For Rotation And Visualization Of N-Dimensional Point Sets, William A. Barrett, Kirk L. Duffin

Faculty Publications

We present a new method for creating n-dimensional rotation matrices from manipulating the projections of n-dimensional data coordinate axes onto a viewing plane. A user interface for n-dimensional rotation is implemented. The interface is shown to have no rotational hysteresis.

Does Pedagogy Make A Difference?: An Experimental Study Of Unethical Behavior In Information Systems, Deepak Khazanchi

Information Systems and Quantitative Analysis Faculty Publications

Jn the past few years ethics education has received increasing attention from the business and academic communities. Many have instituted pedagogical programs for increasing awareness of ethical issues, ethical norms and codes of conduct in different professions. It appears that both researchers and practitioners are in agreement about the need for providing adequate ethics education to managers (13, 20, 9). This has become especially important in the context of the information systems (IS) discipline. Proliferation of information and communication technologies has raised many questions on what constitutes ethical managerial behavior. Researchers have reported that the existence of a computer-based information …

Improved Algorithms For Bipartite Network Flow, Ravindra K. Ahuja, James B. B. Orlin, Clifford Stein, Robert E. Tarjan

Dartmouth Scholarship

In this paper, network flow algorithms for bipartite networks are studied. A network G = (V,E) is called bipartite if its vertex set V can be partitioned into two subsets V_1 and V_2 such that all edges have one endpoint in V_1 and the other in $V_2 $. Let $n = |V|, n_1 = |V_1 | , n_2 = |V_2 |, m = |E| and assume without loss of generality that n_1 \leqslant n_2. A bipartite network is called unbalanced if n_1 \ll n_2 $ and balanced otherwise. (This notion is necessarily imprecise.) It is shown that several maximum flow …

On Editability Of Feature-Based Design, Xiangping Chen, Christoph M. Hoffmann

Department of Computer Science Technical Reports

No abstract provided.

Asymptotically Optimal Heuristics For Bottleneck And Capacity Optimization Problems, Wojciech Szpankowski

Department of Computer Science Technical Reports

No abstract provided.

Bit-Sequences: A Cache Invalidation Algorithm In Mobile Environments, Jin Jing, Omran Bukhres, Ahmed K. Elmagarmid, Rafael Alonso

Department of Computer Science Technical Reports

No abstract provided.

Geometric Contraints For Cagd, Christoph M. Hoffmann, Jörg Peters

Department of Computer Science Technical Reports

No abstract provided.

A Graphics Package For Structural Biology, Ioana Maria Martin, Dan C. Marinescu

Department of Computer Science Technical Reports

No abstract provided.

Distributed Lock Management For Mobile Transactions, Jin Jing, Omran Bukhres, Ahmed K. Elmagarmid

Department of Computer Science Technical Reports

No abstract provided.

A Pattern Matching Model For Misuse Intrusion Detection, Sandeep Kumar, Eugene H. Spafford

Department of Computer Science Technical Reports

No abstract provided.

A Suboptimal Lossy Data Compression Based On Approximate Pattern Matching, Tomasz Luczak, Wojciech Szpankowski

Department of Computer Science Technical Reports

No abstract provided.

Viewing A Graph In A Virtual Reality Display Is Three Times As Good As A 2d Diagram, Colin Ware, Glenn Franck

Center for Coastal and Ocean Mapping

An experiment is reported which tests whether network information is more effectively displayed in a three dimensional space than in a two dimensional space. The experimental task is to trace a path in a network and the experiment is carried out in 2D, in a 3D stereo view, in a 2D view with head coupled perspective, and in a 3D stereo view with head coupled perspective; this last condition creates a localized virtual reality display. The results show that the motion parallax obtained from the head coupling of perspective is more important than stereopsis in revealing structural information. Overall the …

Representing Nodes And Arcs In 3d Networks, Glenn Franck, Colin Ware

Center for Coastal and Ocean Mapping

This paper introduces six graphical principles for 30 network displays. These are justified with examples from GraphVisualizer3D, a system developed by the authors to investigate the problems of 30 visualization of information networks. GraphVisualizer3D enables the exploration of sulface color, surface texture, object shape, arc shape and labeling conventions.

Biofeedback Gait Training Auditory Vs. Visual Techniques, Timothy D. Hiemenz

Electrical & Computer Engineering Theses & Dissertations

Training lower extremity amputees to walk normally is quite a difficult task. Amputees must wear a prosthesis so they can walk at all. This allows them some mobility, but their walking pattern may be unnatural. If their gait is temporally asymmetric, they need to exert more energy to move about. This research was initiated to help lower extremity amputees to walk more efficiently using biofeedback gait training. Two types of feedback were developed and tested to determine which method gave the most understandable feedback, validating its use in a clinical setting.

A normal gait cycle uses the lower limbs to …

Defining Locally Shared Memory Constructs For Special Purpose Parallel Architectures, David J. Nielsen

Electrical & Computer Engineering Theses & Dissertations

Locally shared memory systems offer significant advantages over other parallel processing systems for specific classes of problems. Locally shared memory systems tend to be easier to program because explicit passing of messages is not necessary. The goal in defining a locally shared memory system is to allow only a small number of processors access to any single memory. If this goal is met, locally shared memory systems provide an architecture which is relatively simple to implement.

To make shared memory architectures attractive to designers of special purpose parallel architectures, the architectures must be scalable. To be scalable, the number of …

A Multiprocessor Extension To The Conventional File System Interface, Nils Nieuwejaar, David Kotz

Computer Science Technical Reports

As the I/O needs of parallel scientific applications increase, file systems for multiprocessors are being designed to provide applications with parallel access to multiple disks. Many parallel file systems present applications with a conventional Unix-like interface that allows the application to access multiple disks transparently. By tracing all the activity of a parallel file system in a production, scientific computing environment, we show that many applications exhibit highly regular, but non-consecutive I/O access patterns. Since the conventional interface does not provide an efficient method of describing these patterns, we present an extension which supports strided and nested-strided I/O requests.

Fluted Formulas And The Limits Of Decidability, William C. Purdy

Electrical Engineering and Computer Science - Technical Reports

In the predicate calculus, variables provide a flexible indexing service that selects the actual arguments to a predicate letter from among possible arguments that precede the predicate letter (in the parse of the formula). In the process of selection, the possible arguments can be permuted, repeated (used more than once), and skipped. If this service is withheld, so that arguments must be the immediately preceding ones, taken in the order in which they occur, the formula is said to be fluted. Quine showed that if a fluted formula contains only homogeneous conjunction (conjoins only subformulas of equal arity), then the …

A Domain-Specific Parallel Programming System I: Design And Application To Ecological Modelling, Elaine Wenderholm, Micah Beck

Electrical Engineering and Computer Science - Technical Reports

The goal of the εm project is to make parallel programming easily accessible to a broad community of scientists. Previous approaches such as the use of general parallel programming languages and parallelizing compilers for sequential languages have fallen short in this respect. The approach is to design a special purpose programming language which is oriented towards a specific area of application. The result is a specialized and effective scientific tool. εm is a high-level programming system which puts parallelism into the hands of scientists who are not sophisticated programmers. By restricting and simplifying the programming interface, εm eases both the …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 10, Number 7, September 1994, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

An eight page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

An Empirical Study On End Users' Update Performance For Different Abstraction Levels, Hock Chuan Chan, Kwok Kee Wei, Keng Siau

Research Collection School Of Computing and Information Systems

Recent laboratory experiments have shown a strong tendency that database users can perform better at the conceptual level than at the logical level. The experiments measured users’ performance for the tasks of database design and database retrieval. Besides database design and retrieval, the third major database task is update. User performance for updates has not been measured. With the widespread availability of databases, updates will be done frequently by end-users. This task is gaining in importance as a measure of the usability of a database system. An experiment was conducted to measure the effect of different abstraction levels on user …

Eighth-Order Explicit Symplecticrunge-Kutta-Nyström Integrators, Daniel I. Okunbor, Eric J. Lu

Computer Science Technical Reports

We consider the solution of Hamiltonian dynamical systems by constructing eighth-order explicit symplectic Runge-Kutta-Nyström integrators. The application of highorder integrators may be important in areas such as in astronomy. They require large number of function evaluations, which make them computationally expensive and easily susceptible to errors. The integrators developed in this paper require 17 function evaluations as opposed to the 26-stage (effectively 24) eighth-order explicit symplectic Runge-Kutta-Nyström method derived by Calvo and Sanz-Serna. Numerical tests using the 2-Body and the sine-Gordon problems indicate that our methods are comparable to that of Calvo and Sanz-Serna and Yoshida.

Objects To The Rescue! Or Httpd: The Next Generation Operating System, Andrew P. Black, Jonathan Walpole

Computer Science Faculty Publications and Presentations

This position paper suggests that object-oriented operating systems may provide the means to meet the ever-growing demands of applications. As an example of a successful OOOS, we cite the http daemon. To support the contention that httpd is in fact an operating system, we observe that it implements uniform naming, persistent objects and an invocation meta-protocol, specifies and implements some useful objects, and provides a framework for extensibility.We also believe that the modularity that is characteristic of OO systems should provide a performance benefit rather than a penalty. Our ongoing work in the Synthetix project at OGI is exploring the …