Digital Commons Network^™

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 …

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.

The Internet Instructional Aid, Dohyon Donte Kim

Theses Digitization Project

The development and use of this instructional software tool for the Internet contributes broadly to the increasing sophistication and practical nature of Internet interactive development and programming and specifically to the burgeoning of interactive instructional distance technologies made available by the unique nature of the Internet.

Internet Instructional Aid (IIA) is a software package that utilizes the WEB to teach educational courses online. The purpose of this software-package is to provide an environment in which students can have additional group and individual contact with the instructor and convenient access to prior class lectures and instructional materials. Utilizing Java, the newly …

The Deconstruction Of Mathematics, David J. Stucki

ACMS Journal 2004

Mathematics, as an academic discipline, has stood for many years as the last bastion against a growing tide of intellectual relativism that has become all but ubiquitous. More recently, however, efforts have been made to "humanize" mathematics by advocating a social-constructivist approach to the philosophy of mathematics, both in practice and education. This paper is intended to serve as a critical response to one advocate of this approach, Reuben Hersh (What Is Mathematics, Really?, 1997), and in the process a defense of Platonism.

Cooperative Text And Line Art Extraction From A Topographic Map, Luyang Li, George Nagy, Ashok Samal, Sharad C. Seth, Yihong Xu

School of Computing: Conference and Workshop Papers

The black layer is digitized from a USGS topographic map digitized at 1000 dpi. The connected components of this layer are analyzed and separated into line art, text, and icons in two passes. The paired street casings are converted to polylines by vectorization and associated with street labels from the character recognition phase. The accuracy of character recognition is shown to improve by taking account of the frequently occurring overlap of line art with street labels. The experiments show that complete vectorization of the black line-layer bitmap is the major remaining problem.

Truce: Agent Coordination Through Concurrent Interpretation Of Role-Based Protocols, Wilfred C. Jamison, Douglas Lea

Electrical Engineering and Computer Science - All Scholarship

Established protocols for coordination are essential for implementing joint-action activities among collaborating software agent. Most existing agents, however, are designed only to support static protocols, which limit their interaction domain to specific sets of agents. We develop an agent collaboration framework for open systems that enables an agent to expand its acquaintance set and to adapt to various coordination protocols dynamically. This is achieved through writing coordination scripts that are interpreted at collaboration time. We developed a role-based coordination language for writing these scripts, where the coordination mechanism used is the concurrent interpretation of a single script by the participants …

A Unifying Framework Supporting The Analysis And Development Of Safe Regression Test Selection Techniques, John Bible, Gregg Rothermel

School of Computing: Technical Reports

Safe regression test selection (RTS) techniques let software testers reduce the number of test cases that need to be rerun to revalidate new versions of software, while ensuring that no fault-revealing test case (in the existing test suite) is excluded. Most previous work on safe regression test selection has focused on specific safe RTS algorithms, rather than addressing the theoretical foundations of safe RTS techniques in general. In this paper, we present a unifying framework for safe RTS that supports the analysis and development of safe RTS techniques. We show that every safe RTS technique is founded on a regression …

Multivalued Mappings, Fixed-Point Theorems And Disjunctive Databases, Pascal Hitzler, Anthony K. Seda

Computer Science and Engineering Faculty Publications

In this paper, we discuss the semantics of disjunctive programs and databases and show how multivalued mappings and their fixed points arise naturally within this context. A number of fixed-point theorems for multivalued mappings are considered, some of which are already known and some of which are new. The notion of a normal derivative of a disjunctive program is introduced. Normal derivatives are normal logic programs which are determined by the disjunctive program. Thus, the well-known single-step operator associated with a normal derivative is single-valued, and its fixed points can be found by well-established means. It is shown how fixed …

Benchmarks And Standards For The Evaluation Of Parallel Job Schedulers, Steve J. Chapin, Walfredo Cirne, Dror G. Feitelson, James Patton Jones

Electrical Engineering and Computer Science - All Scholarship

The evaluation of parallel job schedulers hinges on the workloads used. It is suggested that this be standardized, in terms of both format and content, so as to ease the evaluation and comparison of different systems. The question remains whether this can encompass both traditional parallel systems and metacomputing systems. This paper is based on a panel on this subject that was held at the workshop, and the ensuing discussion; its authors are both the panel members and participants from the audience. Naturally, not all of us agree with all the opinions expressed here...

Webhla - An Interactive Multiplayer Environment For High Performance Distributed Modeling And Simulation, Geoffrey C. Fox, Wojtek Furmanski, Subhash Nair, Hasan T. Ozdemir, Zeynep Odcikin-Ozdemir, Tom A. Pulikal

Northeast Parallel Architecture Center

The process of integrating DoD Modeling and Simulation paradigms around the new HLA/RTI standards proceeds in parallel with the onset of new Object Web standards for distributed objects and componentware, emergent at the crossroads of CORBA, DCOM, Java, and XML based distributed object technologies. We describe here our WebHLA approach which integrates both trends by offering Object Web based implementation of the HLA framework. WebHLA follows a three-tier architecture including: a) Web / Commodity based interactive simulation authoring and runtime front-ends given by Java applets or DirectX multiplayers; b) software bus in the middleware, given by Object Web RTI i.e. …

Comparison Of Scalable Key Distribution Schemes For Secure Group Communication, Lakshminath R. Dondeti, Sarit Mukherjee, Ashok Samal

School of Computing: Conference and Workshop Papers

Scalable secure key distribution is the most important feature of a scalable secure group communication protocol. Most of the existing scalable secure group communication protocols are based on a hierarchical key distribution tree. These schemes can be classified as hierarchical node based schemes and hierarchical key based schemes. In this paper; we compare recently proposed hierarchical key distribution schemes through simulation using real-life multicast group membership traces. Our simulations show that hierarchical node based approaches better distribute encryption cost among the entities of a multicast group. However hierarchical node based schemes “trust” internal nodes of a key distribution tree. We …

Transparent Vs. Opaque Vs. Translucent Wavelength-Routed Optical Networks, Byrav Ramamurthy, Helena Feng, Debasish Datta, Jonathan P. Heritage, Biswanath Mukherjee

School of Computing: Conference and Workshop Papers

A wavelength-routed optical network consists of multi-wavelength crossconnect switches (XCSs) which are interconnected by optical fibers. Some (or all) crossconnects, referred to as nodes in this paper, are also attached to access stations where data from several end-users could be multiplexed onto a single wavelength division multiplexed (WDM) channel. An access station provides optical-to-electronic (O/E) conversion and wice wersa to interface the optical network with conventional electronic equipment. The access station, at an intermediate node, may also be used (as in this study) for signal regenerution on a lightpath. A new call is admitted into the network if a lightpath …

Maintaining Transitive Closure Of Graphs In Sql, Guozhu Dong, Leonid Libkin, Jianwen Su, Limsoon Wong

Kno.e.sis Publications

It is common knowledge that relational calculus and even SQL are not expressive enough to express recursive queries such as the transitive closure. In a real database system, one can overcome this problem by storing a graph together with its transitive closure and maintaining the latter whenever updates to the former occur. This leads to the concept of an incremental evaluation system, or IES.

Much is already known about the theory of IES but very little has been translated into practice. The purpose of this paper is to fill in this gap by providing a gentle introduction to and …

The Design And Performance Of A Pluggable Protocols Framework For Object Request Broker Middleware, Fred Kuhns, Carlos O'Ryan, Douglas C. Schmidt, Jeff Parsons

All Computer Science and Engineering Research

To be an effective platform for performance-sensitive real-time and embedded applications, off-the-shelf OO middleware like CORBA, DCOM, and Java RMI must preserve communication-layer quality of service (QoS) properties to applications end-to-end. However, conventional OO middleware interoperability protocols, such as CORBA's GIOP/IIOP or DCOM's MS-RPC, are not well suited for applications that cannot tolerate the message footprint size, latency, and jitter associated with general-purpose messaging and transport protocols. It is essential, therefore, to develop standard plugable protocols frameworks that allow custom messaging and transport protocols to be configured flexibly and used transparently by applications. This paper provides three contributions to research …

A Rapid Development Of Dependable Applications In Ad Hoc Mobility, Amy L. Murphy

All Computer Science and Engineering Research

Advances in wireless communication and network computing technologies make possible new kinds of applications involving transient interactions among physical components that move across a wide range of spaces, from the confines of a room to the airspace across an ocean, and require no fixed networking infrastructure to communicate with one another. Such components may come together to form ad hoc networks for the purpose of exchanging information or in order to engage in cooperative task-oriented behaviors. Ad hoc networks are assembled, reshaped and taken apart as components move in and out of communication range; all interactions are transient; computations become …

Terabit Burst Switching Progress Report (12/98-6-99), Jonathan S. Turner

All Computer Science and Engineering Research

This report summarizes progress on Washington University's Terabit Burst Switching Project, supported by DARPA and Rome Air Force Laboratory. This project seeks to demonstrate the feasibility of Burst Switching, a new data communication service which can more effectively exploit the large bandwidths becoming available in WDM transmission systems, than conventional communication technologies like ATM and IP-based packet switching. Burst switching systems dynamically assign data bursts to channels in optical data links, using routing information carried in parallel control channels. The project will lead to the construction of a demonstration switch with throughput exceeding 200 Gb/s and scalable to over 10 …

Reliable Communication For Highly Mobile Agents, Amy L. Murphy, Gian Pietro Picco

All Computer Science and Engineering Research

The provision of a reliable communication infrastructure for mobile agents is still an open research issue. The challenge to reliability we address in this work does not come from the possibility of faults, but rather from the mere presence of mobility, which slightly complicates the problem of ensuring the delivery of information even in a fault-free network. For instance, the asynchronous nature of message passing and agent migration may cause situations where messages forever chase a mobile agent that moves frequently from one host to another. Current solutions rely on conventional technologies that either do not provide a solution for …

Multiway Range Trees: Scalable Ip Lookup With Fast Updates, Subhash Suri, George Varghese, Piryank Ramesh Warkhede

All Computer Science and Engineering Research

Internet routers forward packets based on the destination address of a packet. A packet's address is matched against the destination prefixes stored in the router's forwarding table, and the packet is sent to the output interface determined by the longest matching prefix. While some existing schemes work well for IPv4 addresses, we believe that none of the current schemes scales well to IPv6, especially when fast updates are required. As the Internet evolves into a global communication medium, requiring multiple addresses per user, the switch to longer addresses (e.g. IPv6) seems inevitable despite temporary measures such as network addres translation …

Design Issues For High Performance Active Routers, Tilman Wolf, Jonathan Turner

All Computer Science and Engineering Research

Active networking is a general approach to incorporating general-purpose computational capabilities within the communications infrastructure of data networks. This paper proposes a design of a scalable, high performance active router. This is used as a vehicle for studying the key design issues that must be resolved to allow active networking to become a mainstream technology.

Software Engineering For Mobility: A Roadmap, Gruia-Catalin Roman, Gian Pietro Picco, Amy L. Murphy

All Computer Science and Engineering Research

The term distributed computing conjures the image of a fixed network structure whose nodes support the execution of processes that communicate with each other via messages traveling along links. Peer-to-peer communication is feasible but client-server relationships dominate. More recently, servers have been augmented with brokerage capabilities to facilitate discovery of available services. Stability is the ideal mode of operation; changes are relatively slow; even in the case of failure, nodes and links are expected eventually to come back up. By contrast, mobility represents a total meltdown of all the stability assumptions (explicit or implicit) associated with distributed computing. The network …

Multiple Stochastic Learning Automata For Vehicle Path Control In An Automated Highway System, Cem Unsal, Pushkin Kachroo, John S. Bay

Electrical & Computer Engineering Faculty Research

This paper suggests an intelligent controller for an automated vehicle planning its own trajectory based on sensor and communication data. The intelligent controller is designed using the learning stochastic automata theory. Using the data received from on-board sensors, two automata (one for lateral actions, one for longitudinal actions) can learn the best possible action to avoid collisions. The system has the advantage of being able to work in unmodeled stochastic environments, unlike adaptive control methods or expert systems. Simulations for simultaneous lateral and longitudinal control of a vehicle provide encouraging results

The World Wide Web, H. Berghel, Doug Blank

Computer Science Faculty Research and Scholarship

No abstract provided.

Radical Artificial Intelligence: A Postmodern Approach, Doug Blank

Computer Science Faculty Research and Scholarship

No abstract provided.

A Feature Library Approach To On-Line Image Querying And Retrieval For Topographic Applications, James Carswell

Conference papers

In this paper we address the problem of content-based image retrieval using queries on shape and topology. We focus on the particularities of image databases encountered in typical topographic applications, and present the development of a spatial data management system that enables such queries. The query uses as input user-provided sketches of the shape and spatial configuration of the object (or objects) which should appear in the images to be retrieved. The objective of the search is to retrieve images that contain a configuration of objects sufficiently similar to the one specified in the query. Our novel approach introduces the …

Multi-User Domain Object Oriented (Moo) As A High School Procedure For Foreign Language Acquisition, James A. Backer

CCAC Theses and Dissertations

Foreign language students experience added difficulty when they are isolated from native speakers and from the culture of the target language. It has been posited that MOOs (Multiuser domain Object Oriented) may help to overcome the geographical isolation of these students. MOOs are Internet-based virtual worlds in which people from all over the real world meet for synchronous textual conversations and can interact with asynchronous textual objects found there. Students who enjoy a MOO site may identify with its virtual target language community and find integrative motivation which the literature suggests is necessary for advanced language acquisition.

This study focused …

The Use Of Cooperative Groups In Learning How To Use New Software Programs, James R. Grunwald

CCAC Theses and Dissertations

Many teachers lament the fact that they often need to spend too much classroom time training students how to use a particular software program before their students can use it effectively as a tool to complete other course work. Also, after completing the training process, too many students still have not mastered the basics of how to use the program effectively. The purpose of this research was to increase understanding of how the use of cooperative groups during new software training affects both the mastery of the basics of program use, as well as the amount of time needed to …

International Usability, Design Guidelines And Effectiveness Of A World Wide Web-Based Instructional Program For High School Students In A Cross-Culture Learning Environment, Hajime Hayakawa

CCAC Theses and Dissertations

The recent growth of the Internet and the World Wide Web (WWW) has resulted in a vast array of on-line courseware and educational Web sites. Unfortunately, as a large percentage of this information is written in English, non-English speakers are unable to access it. Information written in other languages is likewise unavailable to many native English speakers. Therefore, in order to maximize the usefulness of educational material on the Web, it is necessary to design and implement cross-cultural, bilingual or multilingual Web sites and instructional programs.

This study was designed to contribute to the area of bilingual learning on the …

A Theoretical Model For A Prescription Drug Public Key Cryptographic System, Donald R. Lemma

CCAC Theses and Dissertations

A critical component of a physician's duties is prescribing medication to his or her patients. This process is handled by the physician writing a prescription for a medication and having the medication dispensed to the named patient. A review of federal law reveals no requirement that the prescription be issued on any type of specific written instrument such as safety paper, multi-part forms, or other standardized documents.

Because of the lack of adequate controls, there is a serious problem with false and altered prescriptions being issued within the United States. A 1994 study by the White House Office of National …

Linking Printed Books To Computerized Speech, Edward D. Crook

CCAC Theses and Dissertations

Adult students who experience difficulties in comprehending written (printed) language frequently are limited in their scholastic development and possible employment opportunities. These individuals, who represent a growing segment of the learning disabled population, include poor readers and dyslexics and they routinely seek help and remediation through various educational techniques. One remediation technique often used is "books on tape". Through books on tape, recorded spoken text is presented in a sequential manner to the remedial reader as he or she is reading the corresponding printed document. This dissertation reviewed the books on tape paradigm, and through the use of current computer …

Effects Of Parasitic Elements On Oscillation Frequency Of Ota-C Sinusoidal Oscillators, Ari̇f Nacaroğlu, Ergun Erçelebi̇

Turkish Journal of Electrical Engineering and Computer Sciences

An oscillator circuit which incorporates Operational Transconductance Amplifiers is presented. The circuit is designed using three OTAs and two grounded capacitors. The frequency of oscillation is tunable over a wide frequency range. The effects of the parasitic elements on the oscillation frequency and the oscillation condition are studied. The theoretical results are compared with the experimental results for a practical oscillator circuit.