Digital Commons Network^™

Resource Scheduling In A High-Performance Multimedia Server, Hwee Hwa Pang, Bobby Jose, M. S. Krishnan

Research Collection School Of Computing and Information Systems

Supporting continuous media data-such as video and audio-imposes stringent demands on the retrieval performance of a multimedia server. In this paper, we propose and evaluate a set of data placement and retrieval algorithms to exploit the full capacity of the disks in a multimedia server. The data placement algorithm declusters every object over all of the disks in the server-using a time-based declustering unit-with the aim of balancing the disk load. As for runtime retrieval, the quintessence of the algorithm is to give each disk advance notification of the blocks that have to be fetched in the impending time periods, …

The Window Distribution Of Idealized Tcp Congestion Avoidance With Variable Packet Loss, Archan Misra, Teunis J. Ott

Research Collection School Of Computing and Information Systems

This paper analyzes the stationary behavior of the TCP congestion window performing ideal congestion avoidance when the packet loss probability is not constant, but varies as a function of the window size. By neglecting the detailed window behavior during fast recovery, we are able to derive a Markov process that is then approximated by a continuous-time, continuous state space process. The stationary distribution of this process is analyzed and derived numerically and then extrapolated to obtain the stationary distribution of the TCP window. This numerical analysis enables us to predict the behavior of the TCP congestion window when interacting with …

Research And Implementation Of Integrated Concurrent Software Development Environment Based On Object-Oriented Petri Nets, Jinzhong Niu

Publications and Research

While network technologies and environments get more and more popular, the demand for concurrent systems becomes stronger and stronger. But the characteristics of concurrency make it difficult to develop them.

This dissertation combines Object-Oriented technology and Petri Nets theory, and put forth OOPN (OO Petri Nets) model to describe concurrent systems. Based on the research of conventional development methods of concurrent software, this article advances a new one, which integrates specification, validation and auto-generating codes. Accordingly, an integrated development environment for concurrent software, i.e., OOPN-IDE, comes into being, which mainly includes the following four tools: the concurrent system modeling tool …

Continuation-Passing Style Versus Direct Style: Choosing An Intermediate Representation For Higher-Order Applicative Languages, Paul Andrew Seale

Dissertations and Theses

This study analyzes the use of a continuation-passing style (CPS) intermediate representation versus a direct style intermediate representation in the compilation of a higher-order applicative language. The translator used accepts a program written in an ML-like language as input, and outputs a C program acceptable to a standard C compiler. The effects of the translator's simplification and higher-order function removal transformations on the intermediate language are the primary focus of the analysis. The machine code programs generated from both representations are also analyzed.

Initially, the programs under the direct style representation performed better than those that underwent the CPS transformation. …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 2, February 1999, 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.

Structure-Function Relationships In The Pulmonary Arterial Tree, Christopher A. Dawson, Gary S. Krenz, Kelly Lynn Karau, Steven Thomas Haworth, Christopher C. Hanger, John H. Linehan

Mathematics, Statistics and Computer Science Faculty Research and Publications

Knowledge of the relationship between structure and function of the normal pulmonary arterial tree is necessary for understanding normal pulmonary hemodynamics and the functional consequences of the vascular remodeling that accompanies pulmonary vascular diseases. In an effort to provide a means for relating the measurable vascular geometry and vessel mechanics data to the mean pressure-flow relationship and longitudinal pressure profile, we present a mathematical model of the pulmonary arterial tree. The model is based on the observation that the normal pulmonary arterial tree is a bifurcating tree in which the parent-to-daughter diameter ratios at a bifurcation and vessel distensibility are …

Tight Linear Bounds On The Distance Between A Spline And Its B-Spline Control Polygon, David Lutterkort, Jörg Peters

Department of Computer Science Technical Reports

No abstract provided.

Record Matching To Improve Data Quality, Vassilios S. Verykios, Ahmed K. Elmagarmid, Elias N. Houstis

Department of Computer Science Technical Reports

No abstract provided.

Gas Turbine Engine Compressor- Combustor Dynamics Simulation Design, Sanford Fleeter, Elias N. Houstis, John R. Rice, Chem Zhou

Department of Computer Science Technical Reports

No abstract provided.

Domain Architecture A Design Framework For System Development And Integration, Vassilka D. Kirova

Dissertations

The ever growing complexity of software systems has revealed many short-comings in existing software engineering practices and has raised interest in architecture-driven software development. A system's architecture provides a model of the system that suppresses implementation detail, allowing the architects to concentrate on the analysis and decisions that are most critical to structuring the system to satisfy its requirements. Recently, interests of researchers and practi-tioners have shifted from individual system architectures to architectures for classes of software systems which provide more general, reusable solutions to the issues of overall system organization, interoperability, and allocation of services to system components. These …

Parallelization For Image Processing Algorithms Based Chain And Mid-Crack Codes, Wai-Tak Wong

Dissertations

Freeman chain code is a widely-used description for a contour image. Another mid-crack code algorithm was proposed as a more precise method for image representation. We have developed a coding algorithm which is suitable to generate either chain code description or mid-crack code description by switching between two different tables. Since there is a strong urge to use parallel processing in image related problems, a parallel coding algorithm is implemented. This algorithm is developed on a pyramid architecture and a N cube architecture. Using link-list data structure and neighbor identification, the algorithm gains efficiency because no sorting or neighborhood pairing …

A Methodology For Component-Based System Integration, Yongming Tang

Dissertations

Component-based software based on software architectures is emerging to be the next generation software development paradigm. The paradigm shifts the development focus from lines-of-codes to coarser-grained components and the interconnections among them. It consists of system architecture design, architecture description, component search and system integration from components to generate a software system.

However, one of the bottlenecks in this paradigm is the integration of the individual components into the overall system. In this dissertation a methodology for component-based system integration is proposed. It is based on an architectural aggregation view, a component model, flowgraphs and cyclomatic complexity. We introduce this …

A Comparative Study Of Sequence Analysis Tools In Computational Biology, Wei-Jen Chuang

Theses

A biomolecular object, such as a deoxyribonucleic acid (DNA), a ribonucleic acid (RNA) or a protein molecule, is made up of a long chain of subunits. A protein is represented as a sequence made from 20 different amino acids, each represented as a letter. There are a vast number of ways in which similar structural domains can be generated in proteins by different amino acid sequences. By contrast, the structure of DNA, made up of only four different nucleotide building blocks that occur in two pairs, is relatively simple, regular, and predictable.

Biomolecular sequence alignment/string search is the most important …

Iceberg Database System For The Graduate Advisors Of Computer And Information Science Department Of New Jersey Institute Of Technology, Tao Lin

Theses

Iceberg system is a departmental database system. It is built for the graduate advisors of the CIS department. It stores the graduate student's information, such as background, bridge requirement and transcript. The graduate advisors can process the student's records using the graphic user interface of Iceberg system.

Iceberg system is an example of the powerful Java language. We use the latest Java technologies to build a flexible system, which is easily extended. The system consists of Iceberg client, Iceberg server and Oracle data source. The Iceberg client is a web-based applet, which can be easily accessed using a browser. The …

Comparison Of Dcom And Corba Distributed Computing, Reginald J. Reynolds

Theses

The movement of distributed applications from 2-tier to n-tier architectures have enabled systems to be scaled to meet the demands of an ever increasing population of users. Two middleware architectures have come to the forefront: Microsoft's DCOM and the OMG's CORBA. These are not the only possible architectures for n-tier distributed applications, but they are currently the only two which offer a degree of platform independence and the flexibility of using different programming languages for development.

CORBA provides platform independence because it provides a middle layer between the client and the server and services client requests using its internal naming …

Green Manufacturing Of Ammunition Through Knowledge Management With Distributed Access, Ali H. Dogru, Murat M. Tanik, Franz J. Kurfess, Marcus Healey, Leon Jololian

Computer Science and Software Engineering

This paper describes a distributed software requirements gathering methodology dealing with knowledge management for environmentally safer production and lifecycle aspects of tank ammunition. A requirements elicitation methodology is adapted and implemented as a distributed access tool on the Internet. This tool is used for gathering the requirements related information for a specific ammunition production process. During product development, requirements negotiation is the process where the customer needs are identified. This process is regarded as one of the most important parts of building a system because during this stage it is decided precisely what will be built. The concept has been …

The Xrcl Project: The University Of Arkansas' Entry Into The Aaai 1999 Mobile Robot Competition, Doug S. Blank, Jared H. Hudson, Brian C. Mashburn, Eric A. Roberts

Computer Science Faculty Research and Scholarship

No abstract provided.

Java’S Insecure Parallelism, Per Brinch Hansen

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

The author examines the synchronization features of Java and finds that they are insecure variants of his earliest ideas in parallel programming published in 1972-73. The claim that Java supports monitors is shown to be false. The author concludes that Java ignores the last twenty-five years of research in parallel programming languages.

Formal Development Of Secure Email, Dan Zhou, Joncheng C. Kuo, Susan Older, Shiu-Kai Chin

Electrical Engineering and Computer Science - All Scholarship

Developing systems that are assured to be secure requires precise and accurate descriptions of specifications, designs, implementations, and security properties. Formal specification and verification have long been recognized as giving the highest degree of assurance. In this paper, we describe a software development process that integrates formal verification and synthesis. We demonstrate this process by developing assured sender and receiver C++ code for a secure electronic mail system, Privacy Enhanced Mail. We use higher-order logic for system-requirements specification, design specifications and design verification. We use a combination of higher-order logic and category theory and tools supporting these formalisms to refine …

Minitel Versus The Internet In France, Ruthie Kerr

Capstone Research Projects

No abstract provided.

The Gateway System: Uniform Web Based Access To Remote Resources, Geoffrey C. Fox, Tomasz Haupt, Erol Akarsu, Alexey Kalinichenko, Kang-Seok Kim

Northeast Parallel Architecture Center

Exploiting our experience developing the WebFlow system, we designed the Gateway system to provide seamless and secure access to computational resources at ASC MSRC. The Gateway follows our commodity components strategy, and it is implemented as a modern three-tier system. Tier 1 is a high-level front end for visual programming, steering, run-time data analysis and visualization that is built on top of the Web and OO commodity standards. Distributed object-based, scalable, and reusable Web server and Object broker middleware forms Tier 2. Back-end services comprise Tier 3. In particular, access to high-performance computational resources is provided by implementing the emerging …

Thoughts On The Structure Of An Mpj Reference Implementation, Mark Baker, Bryan Carpenter

Northeast Parallel Architecture Center

We sketch a proposed reference implementation for MPJ, the Java Grande Forum's MPI-like message-passing API [9, 3]. The proposal relies heavily on RMI and Jini for finding computational resources, creating slave processes, and handling failures. User-level communication is implemented efficiently directly on top of Java sockets.

Join Index Hierarchy: An Indexing Structure For Efficient Navigation In Object-Oriented Databases, Jiawei Han, Zhaohui Xie, Yongjian Fu

Computer Science Faculty Research & Creative Works

A novel indexing structure - join index hierarchy - is proposed to handle the 'gotos on disk' problem in object-oriented query processing. The method constructs a hierarchy of join indices and transforms a sequence of pointer chasing operations into a simple search in an appropriate join index file, and thus accelerates navigation in object-oriented databases. The method extends the join index structure studied in relational and spatial databases, supports both forward and backward navigations among objects and classes, and localizes update propagations in the hierarchy. Our performance study shows that partial join index hierarchy outperforms several other indexing mechanisms in …

A Model-Based Approach For Compression Of Fingerprint Images, Fikret Erçal, M. Gokmen, Ilker Ersoy

Computer Science Faculty Research & Creative Works

We propose a new fingerprint image compression scheme based on the hybrid model of an image. Our scheme uses the essential steps of a typical automated fingerprint identification system (AFIS) such as enhancement, binarization and thinning to encode fingerprint images. The decoding process is based on reconstructing a hybrid surface by using the gray values on ridges and valleys. In this compression scheme, the ridge skeleton is coded efficiently by using differential chain codes. The valley skeleton is derived from the ridge skeleton and the gray values along the ridge and valley skeletons are encoded using the discrete cosine transform. …

The Gateway System: Uniform Web Based Access To Remote Resources, Tomasz Haupt, Erol Akarsu, Geoffrey C. Fox, Alexey Kalinichenko

Northeast Parallel Architecture Center

Exploiting our experience developing the WebFlow system, we designed the Gateway system to provide seamless and secure access to computational resources at ASC MSRC. The Gateway follows our commodity components strategy, and it is implemented as a modern three-tier system. Tier 1 is a high-level front-end for visual programming, steering, run-time data analysis and visualization, built on top of the Web and OO commodity standards. Distributed object-based, scalable, and reusable Web server and Object broker middleware forms Tier 2. Back-end services comprise Tier 3. In particular, access to high performance computational resources is provided by implementing the emerging standard for …

Websearch: A Configurable Parallel Multi-Search Web Browser, Jason Lin

Theses Digitization Project

No abstract provided.

Formal Analysis Of A Secure Communication Channel: Secure Core-Email Protocol, Dan Zhou, Shiu-Kai Chin

Electrical Engineering and Computer Science - All Scholarship

To construct a highly-assured implementation of secure communication channels we must have clear definitions of the security services, the channels, and under what assumptions these channels provide the desired services. We formally define secure channel services and develop a detailed example. The example is a core protocol common to a family of secure email systems. We identify the necessary properties of cryptographic algorithms to ensure that the email protocol is secure, and we verify that the email protocol provides secure services under these assumptions. We carry out the definitions and verifications in higher-order logic using the HOL theorem-prover. All our …

Performance Analysis Of Csma And Btma Protocols In Multihop Networks: Part Ii - Multiple Channel Case, Lin Wu, Pramod K. Varshney

Electrical Engineering and Computer Science - All Scholarship

Busy tone multiple access protocols have been used in multihop networks to reduce the effect of the hidden terminal problem. This paper demonstrates another approach to reduce the effect of the hidden terminal problem namely the use of multiple channel schemes. A protocol that uses both the busy tone and the multiple channel techniques achieves the best performance. Using a Markov chain model and an approximation, the throughput performance of the multiple channel nonpersistent CSMA protocol and the multiple channel conservative BTMA protocol in a large network is evaluated and compared. The results show that the multichannel CSMA and BTMA …

Pi-Web Join In A Web Warehouse, Sanjay Kumar Madria, Wee Keong Ng, Ee-Peng Lim, Sourav S. Bhowmick

Computer Science Faculty Research & Creative Works

With the enormous amount of data stored in the World Wide Web, it is increasingly important to design and develop powerful web warehousing tools. The key objective of our web warehousing project, called WHOWEDA (Warehouse of Web Data), is to design and implement a web warehouse that materializes and manages useful information from the web. We introduce the concept of Π-web join in the context of WHOWEDA. Pi-web join operator is a web information manipulation operator to combine relevant web information residing in two web tables. Informally, it is the combination of web join and web project operators which filter …

Customizable And Ontology-Enhanced Medical Information Retrieval Interfaces, Gondy Leroy, K.M. Tolle, Hsinchun Chen

CGU Faculty Publications and Research

This paper describes the development and testing of the Medical Concept Mapper as an aid to providing synonyms and semantically related concepts to improve searching. All terms are related to the userquery and fit into the query context. The system is unique because its five components combine humancreated and computer-generated elements. The Arizona Noun Phraser extracts phrases from natural language user queries. WordNet and the UMLS Metathesaurus provide synonyms. The Arizona Concept Space generates conceptually related terms. Semantic relationships between queries and concepts are established using the UMLS Semantic Net. Two user studies conducted to evaluate the system are described.