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Introduction: Data Communication And Topology Algorithms For Sensor Networks, Stephan Olariu, David Simplot-Ryl, Ivan Stojmenovic Jan 2005

Introduction: Data Communication And Topology Algorithms For Sensor Networks, Stephan Olariu, David Simplot-Ryl, Ivan Stojmenovic

Computer Science Faculty Publications

(First paragraph) We are very proud and honored to have been entrusted to be Guest Editors for this special issue. Papers were sought to comprehensively cover the algorithmic issues in the “hot” area of sensor networking. The concentration was on network layer problems, which can be divided into two groups: data communication problems and topology control problems. We wish to briefly introduce the five papers appearing in this special issue. They cover specific problems such as time division for reduced collision, fault tolerant clustering, self-stabilizing graph optimization algorithms, key pre-distribution for secure communication, and distributed storage based on spanning trees …


Metadata And Buckets In The Smart Object, Dumb Archive (Soda) Model, Michael L. Nelson, Kurt Maly, Delwin R. Croom Jr., Steven W. Robbins Jan 2004

Metadata And Buckets In The Smart Object, Dumb Archive (Soda) Model, Michael L. Nelson, Kurt Maly, Delwin R. Croom Jr., Steven W. Robbins

Computer Science Faculty Publications

We present the Smart Object, Dumb Archive (SODA) model for digital libraries (DLs), and discuss the role of metadata in SODA. The premise of the SODA model is to "push down" many of the functionalities generally associated with archives into the data objects themselves. Thus the data objects become "smarter", and the archives "dumber". In the SODA model, archives become primarily set managers, and the objects themselves negotiate and handle presentation, enforce terms and conditions, and perform data content management. Buckets are our implementation of smart objects, and da is our reference implementation for dumb archives. We also present our …


Resource Harvesting Within The Oai-Pmh Framework, Herbert Van De Sompel, Michael L. Nelson, Carl Lagoze, Simeon Warner Jan 2004

Resource Harvesting Within The Oai-Pmh Framework, Herbert Van De Sompel, Michael L. Nelson, Carl Lagoze, Simeon Warner

Computer Science Faculty Publications

Motivated by preservation and resource discovery, we examine how digital resources, and not just metadata about resources, can be harvested using the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH). We review and critique existing techniques for identifying and gathering digital resources using metadata harvested through the OAI-PMH. We introduce an alternative solution that builds on the introduction of complex object formats that provide a more accurate way to describe digital resources. We argue that the use of complex object formats as OAI-PMH metadata formats results in a reliable and attractive approach for incremental harvesting of resources using the OAI-PMH.


Report On The Third Acm/Ieee Joint Conference On Digital Libraries (Jcdl), Michael L. Nelson Jan 2003

Report On The Third Acm/Ieee Joint Conference On Digital Libraries (Jcdl), Michael L. Nelson

Computer Science Faculty Publications

The Third ACM/IEEE Joint Conference on Digital Libraries (JCDL 2003) was held on the campus of Rice University in Houston, Texas, May 27 - 31. Regarding the merging of the ACM and IEEE conference series, in the JCDL 2002 conference report published last year in D-Lib Magazine Edie Rasmussen noted, "Perhaps by next year...no one will remember that it wasn't always so" [1]. Judging by the number of participants I met who did not know that the ACM and IEEE used to hold separate digital library conferences, Rasmussen's prediction has come to pass.


Object Persistence And Availability In Digital Libraries, Michael L. Nelson, B. Danette Allen Jan 2002

Object Persistence And Availability In Digital Libraries, Michael L. Nelson, B. Danette Allen

Computer Science Faculty Publications

We have studied object persistence and availability of 1,000 digital library (DL) objects. Twenty World Wide Web accessible DLs were chosen and from each DL, 50 objects were chosen at random. A script checked the availability of each object three times a week for just over 1 year for a total of 161 data samples. During this time span, we found 31 objects (3% of the total) that appear to no longer be available: 24 from PubMed Central, 5 from IDEAS, 1 from CogPrints, and 1 from ETD.


A Scalable Architecture For Harvest-Based Digital Libraries, Xiaoming Liu, Tim Brody, Stevan Harnard, Les Carr, Kurt Maly, Mohammad Zubair, Michael L. Nelson Jan 2002

A Scalable Architecture For Harvest-Based Digital Libraries, Xiaoming Liu, Tim Brody, Stevan Harnard, Les Carr, Kurt Maly, Mohammad Zubair, Michael L. Nelson

Computer Science Faculty Publications

This article discusses the requirements of current and emerging applications based on the Open Archives Initiative (OAI) and emphasizes the need for a common infrastructure to support them. Inspired by HTTP proxy, cache, gateway and web service concepts, a design for a scalable and reliable infrastructure that aims at satisfying these requirements is presented. Moreover, it is shown how various applications can exploit the services included in the proposed infrastructure. The article concludes by discussing the current status of several prototype implementations.


Federated Searching Interface Techniques For Heterogeneous Oai Repositories, Xiaoming Liu, Kurt Maly, Mohammad Zubair, Qiaoling Hong, Michael L. Nelson, Frances Knudson, Irma Holtkamp Jan 2002

Federated Searching Interface Techniques For Heterogeneous Oai Repositories, Xiaoming Liu, Kurt Maly, Mohammad Zubair, Qiaoling Hong, Michael L. Nelson, Frances Knudson, Irma Holtkamp

Computer Science Faculty Publications

Federating repositories by harvesting heterogeneous collections with varying degrees of metadata richness poses a number of challenging issues: (1) how to address the lack of uniform control for various metadata fields in terms of building a rich unified search interface, and (2) how easily new collections and freshly harvested data in existing repositories can be incorporated into the federation supporting a unified interface? This paper focuses on the approaches taken to address these issues in Arc, an Open Archives Initiative compliant federated digital library. At present Arc contains over 1M metadata records from 75 data providers from various subject domains. …


Arc - An Oai Service Provider For Digital Library Federation, Xiaoming Liu, Kurt Maly, Mohammad Zubair, Michael L. Nelson Jan 2001

Arc - An Oai Service Provider For Digital Library Federation, Xiaoming Liu, Kurt Maly, Mohammad Zubair, Michael L. Nelson

Computer Science Faculty Publications

The usefulness of the many on-line journals and scientific digital libraries that exist today is limited by the inability to federate these resources through a unified interface. The Open Archive Initiative (OAI) is one major effort to address technical interoperability among distributed archives. The objective of OAI is to develop a framework to facilitate the discovery of content in distributed archives. In this paper, we describe our experience and lessons learned in building Arc, the first federated searching service based on the OAI protocol. Arc harvests metadata from several OAI compliant archives, normalizes them, and stores them in a search …


Buckets: Smart Objects For Digital Libraries, Michael L. Nelson Jan 2001

Buckets: Smart Objects For Digital Libraries, Michael L. Nelson

Computer Science Faculty Publications

Current discussion of digital libraries (DLs) is often dominated by the merits of the respective storage, search and retrieval functionality of archives, repositories, search engines, search interfaces and database systems. While these technologies are necessary for information management, the information content is more important than the systems used for its storage and retrieval. Digital information should have the same long-term survivability prospects as traditional hardcopy information and should be protected to the extent possible from evolving search engine technologies and vendor vagaries in database management systems. Information content and information retrieval systems should progress on independent paths and make limited …


Smart Objects And Open Archives, Michael L. Nelson, Kurt Maly Jan 2001

Smart Objects And Open Archives, Michael L. Nelson, Kurt Maly

Computer Science Faculty Publications

Within the context of digital libraries (DLs), we are making information objects "first-class citizens". We decouple information objects from the systems used for their storage and retrieval, allowing the technology for both DLs and information content to progress independently. We believe dismantling the stovepipe of "DL-archive-content" is the first step in building richer DL experiences for users and insuring the long-term survivability of digital information. To demonstrate this partitioning between DLs, archives and information content, we introduce "buckets": aggregative, intelligent, object-oriented constructs for publishing in digital libraries. Buckets exist within the "Smart Object, Dumb Archive" (SODA) DL model, which promotes …


The Ups Prototype: An Experimental End-User Service Across E-Print Archives, Herbert Van De Sompel, Thomas Krichel, Michael L. Nelson, Patrick Hochstenbach, Victor Lyapunov, Kurt Maly, Mohammad Zubair, Mohamed Kholief, Xiaoming Liu, Heath O'Connell Jan 2000

The Ups Prototype: An Experimental End-User Service Across E-Print Archives, Herbert Van De Sompel, Thomas Krichel, Michael L. Nelson, Patrick Hochstenbach, Victor Lyapunov, Kurt Maly, Mohammad Zubair, Mohamed Kholief, Xiaoming Liu, Heath O'Connell

Computer Science Faculty Publications

A meeting was held in Santa Fe, New Mexico, October 21-22, 1999, to generate discussion and consensus about interoperability of publicly available scholarly information archives. The invitees represented several well known e-print and report archive initiatives, as well as organizations with interests in digital libraries and the transformation of scholarly communication. The central goal of the meeting was to agree on recommendations that would make the creation of end-user services -- such as scientific search engines and linking systems -- for data originating from distributed and dissimilar archives easier. The Universal Preprint Service (UPS) Prototype was developed in preparation for …


Smart Objects, Dumb Archives: A User-Centric, Layered Digital Library Framework, Kurt Maly, Michael L. Nelson, Mohammad Zubair Jan 1999

Smart Objects, Dumb Archives: A User-Centric, Layered Digital Library Framework, Kurt Maly, Michael L. Nelson, Mohammad Zubair

Computer Science Faculty Publications

Discusses digital libraries, interoperability, and interfaces to access them, and proposes one universal protocol for communication for simple archives based on the hypertext transfer protocol (http). Describes the creation of a special class of digital objects called buckets, archives based on a NASA collection, and a set of digital library services. (Author/LRW)


Compute As Fast As The Engineers Can Think! Utrafast Computing Team Final Report, Robert T. Biedron, P. Mehrotra, Michael L. Nelson, M. L. Preston, J. J. Rehder, J. L. Rogersm, D. H. Rudy, J. Sobieski, O. O. Storaasli Jan 1999

Compute As Fast As The Engineers Can Think! Utrafast Computing Team Final Report, Robert T. Biedron, P. Mehrotra, Michael L. Nelson, M. L. Preston, J. J. Rehder, J. L. Rogersm, D. H. Rudy, J. Sobieski, O. O. Storaasli

Computer Science Faculty Publications

This report documents findings and recommendations by the Ultrafast Computing Team (UCT). In the period 10-12/98, UCT reviewed design case scenarios for a supersonic transport and a reusable launch vehicle to derive computing requirements necessary for support of a design process with efficiency so radically improved that human thought rather than the computer paces the process. Assessment of the present computing capability against the above requirements indicated a need for further improvement in computing speed by several orders of magnitude to reduce time to solution from tens of hours to seconds in major applications. Evaluation of the trends in computer …


A Digital Library For The National Advisory Committee For Aeronautics, Michael L. Nelson Jan 1999

A Digital Library For The National Advisory Committee For Aeronautics, Michael L. Nelson

Computer Science Faculty Publications

We describe the digital library (DL) for the National Advisory Committee for Aeronautics (NACA), the NACA Technical Report Server (NACATRS). The predecessor organization for the National Aeronautics and Space Administration (NASA), NACA existed from 1915 until 1958. The primary manifestation of NACA's research was the NACA report series. We describe the process of converting this collection of reports to digital format and making it available on the World Wide Web (WWW) and is a node in the NASA Technical Report Server (NTRS). We describe the current state of the project, the resulting DL technology developed from the project, and the …


Creating A Canonical Scientific And Technical Information Classification System For Ncstrl+, Melissa E. Tiffany, Michael L. Nelson Jan 1998

Creating A Canonical Scientific And Technical Information Classification System For Ncstrl+, Melissa E. Tiffany, Michael L. Nelson

Computer Science Faculty Publications

The purpose of this paper is to describe the new subject classification system for the NCSTRL+ project. NCSTRL+ is a canonical digital library (DL) based on the Networked Computer Science Technical Report Library (NCSTRL). The current NCSTRL+ classification system uses the NASA Scientific and Technical (STI) subject classifications, which has a bias towards the aerospace, aeronautics, and engineering disciplines. Examination of other scientific and technical information classification systems showed similar discipline-centric weaknesses. Traditional, library-oriented classification systems represented all disciplines, but were too generalized to serve the needs of a scientific and technically oriented digital library. Lack of a suitable existing …


Buckets: Aggregative, Intelligent Agents For Publishing, Michael L. Nelson, Kurt Maly, Stewart N. T. Shen, Mohammad Zubair Jan 1998

Buckets: Aggregative, Intelligent Agents For Publishing, Michael L. Nelson, Kurt Maly, Stewart N. T. Shen, Mohammad Zubair

Computer Science Faculty Publications

Buckets are an aggregative, intelligent construct for publishing in digital libraries. The goal of research projects is to produce information. This information is often instantiated in several forms, differentiated by semantic types (report, software, video, datasets, etc.). A given semantic type can be further differentiated by syntactic representations as well (PostScript version, PDF version, Word version, etc.). Although the information was created together and subtle relationships can exist between them, different semantic instantiations are generally segregated along currently obsolete media boundaries. Reports are placed in report archives, software might go into a software archive, but most of the data and …


Lyceum: A Multi-Protocol Digital Library Gateway, Ming-Hokng Maa, Michael L. Nelson, Sandra L. Esler Jan 1997

Lyceum: A Multi-Protocol Digital Library Gateway, Ming-Hokng Maa, Michael L. Nelson, Sandra L. Esler

Computer Science Faculty Publications

Lyceum is a prototype scalable query gateway that provides a logically central interface to multi-protocol and physically distributed, digital libraries of scientific and technical information. Lyceum processes queries to multiple syntactically distinct search engines used by various distributed information servers from a single logically central interface without modification of the remote search engines. A working prototype (http://www.larc.nasa.gov/lyceum/) demonstrates the capabilities, potentials, and advantages of this type of meta-search engine by providing access to over 50 servers covering over 20 disciplines.


The World Wide Web And Technology Transfer At Nasa Langley Research Center, Michael L. Nelson, David J. Bianco Jan 1994

The World Wide Web And Technology Transfer At Nasa Langley Research Center, Michael L. Nelson, David J. Bianco

Computer Science Faculty Publications

NASA Langley Research Center (LaRC) began using the World Wide Web (WWW) in the summer of 1993, becoming the first NASA installation to provide a Center-wide home page. This coincided with a reorganization of LaRC to provide a more concentrated focus on technology transfer to both aerospace and non-aerospace industry. Use of the WWW and NCSA Mosaic not only provides automated information dissemination, but also allows for the implementation, evolution and integration of many technology transfer applications. This paper describes several of these innovative applications, including the on-line presentation of the entire Technology Opportunities Showcase (TOPS), an industrial partnering showcase …


Electronic Document Distribution: Design Of The Anonymous Ftp Langley Technical Report Server, Michael L. Nelson, Gretchen L. Gottlich Jan 1994

Electronic Document Distribution: Design Of The Anonymous Ftp Langley Technical Report Server, Michael L. Nelson, Gretchen L. Gottlich

Computer Science Faculty Publications

An experimental electronic dissemination project, the Langley Technical Report Server (LTRS), has been undertaken to determine the feasibility of delivering Langley technical reports directly to the desktops of researchers worldwide. During the first six months, over 4700 accesses occurred and over 2400 technical reports were distributed. This usage indicates the high level of interest that researchers have in performing literature searches and retrieving technical reports at their desktops. The initial system was developed with existing resources and technology. The reports are stored as files on an inexpensive UNIX workstation and are accessible over the Internet. This project will serve as …


World Wide Web Implementation Of The Langley Technical Report Server, Michael L. Nelson, Gretchen L. Gottlich, David J. Bianco Jan 1994

World Wide Web Implementation Of The Langley Technical Report Server, Michael L. Nelson, Gretchen L. Gottlich, David J. Bianco

Computer Science Faculty Publications

On January 14, 1993, NASA Langley Research Center (LaRC) made approximately 130 formal, 'unclassified, unlimited' technical reports available via the anonymous FTP Langley Technical Report Server (LTRS). LaRC was the first organization to provide a significant number of aerospace technical reports for open electronic dissemination. LTRS has been successful in its first 18 months of operation, with over 11,000 reports distributed and has helped lay the foundation for electronic document distribution for NASA. The availability of World Wide Web (WWW) technology has revolutionized the Internet-based information community. This paper describes the transition of LTRS from a centralized FTP site to …


A Strategy For Electronic Dissemination Of Nasa Langley Technical Publications, Donna G. Roper, Mary K. Mccaskill, Scott D. Holland, Joanne L. Walsh, Michael L. Nelson, Susan L. Adkins, Manjula Y. Ambur, Bryan A. Campbell Jan 1994

A Strategy For Electronic Dissemination Of Nasa Langley Technical Publications, Donna G. Roper, Mary K. Mccaskill, Scott D. Holland, Joanne L. Walsh, Michael L. Nelson, Susan L. Adkins, Manjula Y. Ambur, Bryan A. Campbell

Computer Science Faculty Publications

To demonstrate NASA Langley Research Center's relevance and to transfer technology to external customers in a timely and efficient manner, Langley has formed a working group to study and recommend a course of action for the electronic dissemination of technical reports (EDTR). The working group identified electronic report requirements (e.g., accessibility, file format, search requirements) of customers in U.S. industry through numerous site visits and personal contacts. Internal surveys were also used to determine commonalities in document preparation methods. From these surveys, a set of requirements for an electronic dissemination system was developed. Two candidate systems were identified and evaluated …


Intel Nx To Pvm 3.2 Message Passing Conversion Library, Trey Arthur, Michael L. Nelson Jan 1993

Intel Nx To Pvm 3.2 Message Passing Conversion Library, Trey Arthur, Michael L. Nelson

Computer Science Faculty Publications

NASA Langley Research Center has developed a library that allows Intel NX message passing codes to be executed under the more popular and widely supported Parallel Virtual Machine (PVM) message passing library. PVM was developed at Oak Ridge National Labs and has become the defacto standard for message passing. This library will allow the many programs that were developed on the Intel iPSC/860 or Intel Paragon in a Single Program Multiple Data (SPMD) design to be ported to the numerous architectures that PVM (version 3.2) supports. Also, the library adds global operations capability to PVM. A familiarity with Intel NX …


A Comparison Of Queueing, Cluster And Distributed Computing Systems, Joseph A. Kaplan, Michael L. Nelson Jan 1993

A Comparison Of Queueing, Cluster And Distributed Computing Systems, Joseph A. Kaplan, Michael L. Nelson

Computer Science Faculty Publications

Using workstation clusters for distributed computing has become popular with the proliferation of inexpensive, powerful workstations. Workstation clusters offer both a cost effective alternative to batch processing and an easy entry into parallel computing. However, a number of workstations on a network does not constitute a cluster. Cluster management software is necessary to harness the collective computing power. A variety of cluster management and queuing systems are compared: Distributed Queueing Systems (DQS), Condor, Load Leveler, Load Balancer, Load Sharing Facility (LSF - formerly Utopia), Distributed Job Manager (DJM), Computing in Distributed Networked Environments (CODINE), and NQS/Exec. The systems differ in …


Pipelining Data Compression Algorithms, R. L. Bailey, R. Mukkamala Jan 1990

Pipelining Data Compression Algorithms, R. L. Bailey, R. Mukkamala

Computer Science Faculty Publications

Many different data compression techniques currently exist. Each has its own advantages and disadvantages. Combining (pipelining) multiple data compression techniques could achieve better compression rates than is possible with either technique individually. This paper proposes a pipelining technique and investigates the characteristics of two example pipelining algorithms. Their performance is compared with other well-known compression techniques.