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Optimizing the NASA technical report server

INTERNET research-ELECTRONIC NETWORKING APPLICATIONS AND POLICY 1996年第1期6卷 64-&页

作者： Nelson, ML Maa, MH Michael L. Nelson is the “webmaster” for NASA Langley Research Center Computer Systems Branch Mail Stop 157A 15 Langley Boulevard Hampton VA 23681‐0001 USA. Tel: 804 8648511 Fax: 804 8648342 E‐mail: <m.l.nelson@larc.nasa.gov> . He has also worked with others to implement report servers software servers technology transfer databases and other World Wide Web services and is also the technical lead for NASA Langley Research Center’s workstation clustering activities. Ming‐Hokng Maa is a NASA Langley Research Center Cooperative Education Student e‐mail: <m.h.maa@larc.nasa.gov> pursuing his BS in computer engineering/computer science at the Massachusetts Institute of Technology. He has previously held research positions at nView Corp. and the Inter‐National Research Institute Inc Ming‐Hokng Maa is a NASA Langley Research Center Cooperative Education Student e‐mail: <m.h.maa@larc.nasa.gov> pursuing his BS in computer engineering/computer science at the Massachusetts Institute of Technology. He has previously held research positions at nView Corp. and the Inter‐National Research Institute Inc

Explains how the NASA Technical Report Server, a World Wide web report distribution NASA technical publications service, has been modified for performance enhancement, greater protocol support and human interface optimization. Results include: parallel database queries, significantly decreasing user access times by an average factor of 2.3;access from clients behind firewalls and/or proxies which truncate excessively long Uniform Resource Locators;access to non-Wide Area Information Server (WAIS) databases and compatibility with the Z39-50.3 protocol;and a streamlined user interface.

关键词： distribution information retrieval information services Internet

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Components on the Internet (panel) 96

Components on the Internet (panel)

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Proceedings of the 11th ACM SIGPLAN conference on Object-oriented programming, systems, languages, and applications

作者： Jeffrey Bonar Nancy Lehrer Kelly Looney Randy Schnier James Russel Ted Selker Stewart Nickolas IBM's Object Technology Austin Texas Senior Scientist ISX Corporation VisualWave Product Line ParcPlace-digitaik's Smalltalk-for-the-Internet development Environment Software engineer IBMss lab in Rochester Minnesota IBM's T.J. Watson Research Center User System Ergonomics Research (USER) IBM Almaden Research Center IBM

ISBN: (纸本)9780897917889

The explosive emergence of the Internet forces us to rethink the traditional roles for client, server, and objects. Component technology has emerged as the way objects and frameworks are packaged for flexible object integration. In particular, components allow users who are not programmers to do their own integration. Up until now, components have mainly focused on object integration on end-users desktops and on a client: compound documents, application assembly, *** component models like OpenDoc and Microsoft's OLE/OCX/COM provide function for compound documents, persistence, scripting, inking, and code management (registration). A series of Internet scenarios are emerging that demand new kinds of components. These scenarios are thin clients (Internet terminals), virtual reality/rich multimedia clients, collaboration, and business data access. Each panelist will explore one of these scenarios for it's requirements on an Internet component model.

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Molecular Dynamics Simulation for the Formation of Magic-Number Clusters with a Lennard-Jones Potential

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Physical Review Letters 1996年第11期76卷 1792-1792页

作者： Tamio Ikeshoji Bjørn Hafskjold Yuichi Hashi Yoshiyuki Kawazoe National Institute for Advanced Interdisciplinary Research 1-1-4 Higashi Tsukuba Ibaraki 305 Japan Department of Physical Chemistry University of Trondheim-Norwegian Institute of Technology N-7034 Trondheim-NTH Norway Research and Development Center Hitachi Tohoku Software Ltd. 2-16-10 Honcho Aoba-ku Sendai 980 Japan Institute for Materials Research Tohoku University Sendai 980-77 Japan

The formation of clusters from a gas state of particles interacting with a Lennard-Jones potential was simulated by a large-scale molecular dynamics calculation with a new temperature-control scheme. Decreasing the translational temperature of atoms and clusters followed by a long-term evaporation produced several peaks in a cluster-size distribution. The peak positions obtained correspond to sizes 13, 19, 23, and 26, which are the magic numbers expected from polyicosahedra.

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LAN fault management ensemble

LAN fault management ensemble

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IEEE Symposium on Network Operations and Management

作者： Y. Teshigawara N. Yoshie A. Komatsu T. Nakakawaji Department of Information Systems Science Engineering Soka University Tokyo Japan Information & Electronics Laboratories Sumitomo Electric Industries Limited Osaka Japan Computer Software Operation Unit Third Computer Software Division NEC Corporation Limited Tokyo Japan Information Technology Research and Development Center Mitsubishi Electric Corporation Limited Kamakura Kanagawa Japan

LAN systems are widely used in distributed environment and it becomes more indispensable to manage distributed LAN systems in an integrated manner as enterprise-level networks. This paper describes the LAN fault management ensemble which has been developed by the Ensemble Team of INTAP NM (Network Management) Technical Committee. Ensembles represent specific solutions to particular problems of the networks as a collection of managed resources, functions and scenarios. This ensemble provides a method of managing an enterprise-level private network in particular fault management areas. OSI management is adopted as a platform to manage LANs which are assumed to be managed by SNMP or OSI layer management protocols. This ensemble takes a state-oriented approach which is better suited, and provides more efficient integrated network management for large-scale enterprise networks containing many resources to be managed, because SNMP management is performed by polling based on the stateless approach. In addition, this ensemble adopts international standards or publicly available specifications regarding the necessary management information. Integrated management is executed by the OSI manager and proxy agents. Proxy agents act as OSI agents and convert information gathered by SNMP manager/agents or OSI layer management entities to OSI. Various network resources such as FDDI, Ethernet and MIB-II are defined on the basis of definition of the ISO/IEC, IEEE and NM Forum standards and additional necessary resources are uniquely defined for this ensemble requirements.

关键词： Local area networks Open systems Resource management Information management ISO standards IEC standards Environmental management Protocols Large scale integration FDDI

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Applications of feasible path analysis to program testing 94

Applications of feasible path analysis to program testing

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Proceedings of the 1994 International Symposium on software Testing and Analysis (ISSTA)

作者： Goldberg, Allen Wang, T.C. Zimmerman, David Kestrel Institute 3260 Hillview Avenue Palo Alto CA Software Technology Center Research and Development Division Lockheed Missiles and Space Company Palo Alto CA

ISBN: (纸本)9780897916837

For certain structural testing criteria a significant proportion of tests instances are infeasible in the sense the semantics of the program implies that test data cannot be constructed that meet the test requirement. This paper describes the design and prototype implementation of a structural testing system that uses a theorem prover to determine feasibility of testing requirements and to optimize the number of test cases required to achieve test coverage. Using this approach, we were able to accurately and efficiently determine path feasibility for moderately-sized program units of production code written in a subset of Ada. On these problems, the computer solutions were obtained much faster and with greater accuracy than manual analysis. The paper describes how we formalize test criteria as control flow graph path expressions; how the criteria are mapped to logic formulas; and how we control the complexity of the inference task. It describes the limitations of the system and proposals for its improvement as well as other applications of the analysis.

关键词： Semantics

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EFFECT OF BROADCAST AND PRECISE EPHEMERIDES ON ESTIMATES OF THE FREQUENCY STABILITY OF GPS NAVSTAR CLOCKS

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INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS 1994年第5期12卷 435-441页

作者： MCCASKILL, TB REID, WG BUISSON, JA WARREN, HE U.S. Naval Research Laboratory Naval Centre for Space Technology Space Applications Branch Washington DC 20375–5320 USA. A physicist who has worked with the Space Applications Branch of the Naval Research Laboratory (NRL) since 1960. He works in the areas of precise time and frequency and satellite navigation. His satellite navigation work began in 1966 with the TIM-ATION program. He developed navigation algorithms that were used in the design of the NRL-proposed constellation for GPS. He has been a member of the GPS team for more than 20 years. His current work involves the frequency stability analysis of all GPS Navstar and monitor station clocks. An Electronics Engineer who has worked at the Naval Research Laboratory since 1971 and with the Space Applications Branch since 1983. He has been a member of the GPS team for more than a decade. His current work involves software development for the clock analysis program and analysis of the Navstar clock behaviour in the areas of anomaly detection correction of breaks in the data frequency stability and spectral analysis. SFA Inc. 1401 McCormick Drive Landover MD 20785 USA. A physicist who has been associated with the Naval Research Laboratory since 1960 and currently is an independent contractor. He has worked on the GPS project for more than 20 years. He was involved with the first experiment in the TIMATION program in 1964 and with the design of the NRL-proposed constellation for GPS. He was the Director of the Control Center for the Navigation Technology Segment (NTS) of GPS which verified key concepts that included precise time transfer navigation and the relativistic clock effect for GPS. An engineer who has been associated with the Space Applications Branch of the Naval Research Laboratory since 1959–first with Bendix Field Engineering until 1990 and currently with SFA Inc. His work includes GPS precise time and frequency measurements for NTS and GPS data communications and analysis of the Navstar clocks.

Frequency stability analysis of on-orbit Navstar clocks is performed by the Naval research Laboratory using both the broadcast and the precise post-processed ephemerides. The phase offset between the Navstar clock and the reference clock is computed from pseudorange measurements obtained by dual-frequency GPS receivers at the five GPS monitor sites and at the U.S. Naval Observatory precise-time site. The broadcast ephemerides are generated at the GPS master control station by a Kalman filter using data collected from the five GPS monitor stations. The precise post-processed ephemerides are generated by the Defense Mapping Agency (DMA) using data collected from the GPS monitor sites and from five additional DMA monitor sites. In this paper the frequency stability is estimated for two Navstar caesium clocks-a Block I caesium clock (Navstar 9) and a Block II caesium clock (Navstar 23)-using both the broadcast and the precise ephemerides. A significant improvement in the estimate of the frequency stability of the Block II clocks has been achieved using the precise ephemeris.

关键词： GPS NAVSTAR CLOCKS FREQUENCY STABILITY BROADCAST AND PRECISE EPHEMERIDES EPHEMERIS PREDICTION UNCERTAINTY

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ASYNCHRONOUS TRANSFER MODE (ATM) OPERATION VIA SATELLITE - ISSUES, CHALLENGES AND RESOLUTIONS

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INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS 1994年第3期12卷 211-222页

作者： CHITRE, DM GOKHALE, DS HENDERSON, T LUNSFORD, JL MATHEWS, N COMSAT Laboratories 22300 Comsat Drive Clarksburg MD 20871 USA. Received his B.Sc. from the University of Bombay India an M.A. in mathematics from the University of Cambridge U.K. and a Ph.D. in physics from the University of Maryland. He is currently an Associate Executive Director of the Network Technology Division at COMSAT Laboratories. He has been involved in research and development activities in ISDN VSAT networks data communications and network systems and architectures. Prior to his current positions Dr. Chitre was a Principal Scientist in the Network Technology Division at COMSAT Laboratories. Dr. Chitre joined COMSAT Laboratories in 1980. He has made major contributions to the analysis and architecture of data communication ISDN and BISDN via satellite. Dr. Chitre directs and participates in the international and national standards activities in ISDN BISDN and data communication as they apply to satellite communication. He was Chairman of the Working Group on Protocols and Network Timing Function of the CCIR/CCITT Joint Ad Hoc Group on ISDN-Satellite Matters during 1990–1992. Currently he is the Chairman of the Working Group on New Technologies in the ITU Intersector Coordinating Group (ICG) on Satellite Matters. Dr. Chitre was a programme manager during 1990 and 1991 on a contract from INTELSAT on systems studies on satellite communications systems architectures for ISDN and broadband ISDN systems. Currently he is the technical manager of the DoD Contract on ATM via satellite demonstration and the programme manager for the INTELSAT contract on analysis and top-level specification of INTELSAT ISDN subnetworks and SDH compatible transport network. Department manager for ISDN/Data Communications in the Network Technology Division of COMSAT Laboratories. His responsibilities include managing the implementation of next generation telecommunication systems for fixed and mobile satellite systems. Current projects include the development of a high data rate gateway switch that provides for the

Key issues regarding the operation of the broadband integrated services digital network (BISDN) via satellite are presented herein. The specific issues, challenges, and their resolutions are detailed. In particular, the impact of error characteristics and propagation delay on the operation of BISDN via satellite is discussed. Solutions are presented for removing adverse effects and providing high-quality service to users of BISDN via satellite.

关键词： ATM BISDN

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THE CALLING(SM) NETWORK - A GLOBAL WIRELESS COMMUNICATION-SYSTEM

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INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS 1994年第1期12卷 45-61页

作者： TUCK, EF PATTERSON, DP STUART, JR LAWRENCE, MH Calling Communications Corporation. 1900 West Garvey Ave South. Suite 200 West Covina CA 91790 USA. Chairman of Calling Communications Corporation. He is also the Managing Director of Kinship Venture Management Inc. the general partner of Kinship Partners 11 and a General Partner of Boundary the general partner of The Boundary Fund. As a venture capitalist he has founded or participated in founding several telecommunications companies including Calling Communications Corporation Magellan Systems Corporation manufactures of Global Positioning System receivers Applied Digital Access manufacturer of DS-3 test access and network performance monitoring equipment Endgate Technology Corporation specialists in satellite phased array antennas and Poynting Systems Corporation. now a division of Reliance Corporation manufacturers of fibre optic transport equipment. He was a founder of Kebby Microwave Corporation where he invented the first solid-state. frequency-modulated commercial microwave link system. The company was acquired by ITT Corporation where he rose to the position of V.P. and Technical Director of ITT North America Telecommunications Inc. Subsequently he was V.P. of Marketing and Engineering at American Telecommunications Inc. (ATC). He was founding Director of American Telecom Inc. a joint venture between ATC and Fujitsu and has served on more than 20 boards of directors including those of three public companies. He has authored articles on microwave engineering and telephone signalling and was a contributor to Reference Data For Radio Engineers. He is a graduate of the University of Missouri at Rolla where he was later awarded an honorary Professional degree and serves on its Academy of Electrical Engineering. Mr Tuck is a Senior Member of the IEEE a Fellow of the Institution of Engineers (Australia) a Professional Member of the AIAA and a registered professional engineer in three states. More than 25 years of experience in the telecommunications industry where he has been responsibl

There is a very large demand for basic telephone service in developing nations, and remote parts of industrialized nations, which cannot be met by conventional wireline and cellular systems. This is the world's largest unserved market. We describe a system which uses recent advances in active phased arrays, fast-packet switching technology, adaptive routeing, and light spacecraft technology, in part based on the work of the Jet Propulsion Laboratory and on recently-declassified work done on the Strategic Defense Initiative, to make it possible to address this market with a global telephone network based on a large low-Earth-orbit constellation of identical satellites. A telephone utility can use such a network to provide the same modern basic and enhanced telephone services offered by telephone utilities in the urban centres of fully-industrialized nations. Economies of scale permit capital and operating costs per subscriber low enough to provide a service to all subscribers, regardless of location, at prices comparable to the same services in urban areas of industrialized nations, while generating operating profits great enough to attract the capital needed for its construction. The bandwidth needed to support the capacity needed to gain these economies of scale requires that the system use K(alpha)-band frequencies. This choice of frequencies places unusual constraints on the network design, and in particular forces the use of a large number of satellites. Global demand for basic and enhanced telephone service is great enough to support at least three networks of the size described herein. The volume of advanced components, and services such as launch services, required to construct and replace these networks is sufficient to propel certain industries to market leadership positions in the early 21st Century.

关键词： LOW EARTH ORBIT SATELLITE COMMUNICATIONS FAST PACKET SWITCHING EARTH FIXED CELLS ADAPTIVE ROUTEING LIGHT SPACECRAFT K(A) BAND PHASED-ARRAY ANTENNAS

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Postprocessing algorithm based on the probabilistic and semantic method for Japanese OCR

Postprocessing algorithm based on the probabilistic and sema...

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International Conference on Document Analysis and Recognition

作者： A. Konno Y. Hongo Software and System Laboratory Fuji Electric Corporate Research and Development Limited Tokyo Japan Technology and Development Center Fuji EIectric Company Limited Tokyo Japan

A postprocessing algorithm for Japanese OCR based on the probabilistic and semantic method is described. It determines the reliability of each recognized character and word in OCR outputs with their recognition probability and appearance frequency in the text. Using these reliabilities, grammatical word paths are searched in each phrase. When it is necessary to select the most suitable word from a similar word set, an attempt is made to select a particular one by the semantic method with co-occurrence word dictionary. This method was applied to OCR outputs of current newspapers and technical documents including some unregistered words, and evaluated its performance. While error correction rate depends on the ratio of unregistered words in the texts, the error detection rate is almost 90%.< >

关键词： Optical character recognition software Character recognition Text recognition Frequency Error correction software algorithms Dictionaries Natural languages software systems Laboratories

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STATISTICAL PROCESS-CONTROL FOR software IN THE MAINTENANCE PHASE

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NAVAL ENGINEERS JOURNAL 1993年第3期105卷 192-200页

作者： LUKE, SR JACOBS, DA REED, BM Stephen R. Luke:is a registered professional engineer in the Commonwealth of Virginia. He received his B.S. in mechanical engineering from Virginia Polytechnic Institute in 1983 and is presently pursuing a master's degree in engineering management at Old Dominion University. Mr. Luke is experienced as a test engineer at the Norfolk Naval Shipyard (1978–1989) and as a reliability/quality engineer at the Naval Undersea Warfare Center Detachment Norfolk (1989-Present). Currently he is the group leader of the RMA/QA group for the AN/SQQ-89(V) Antisubmarine Warfare System at Naval Undersea Warfare Center Detachment Norfolk. Mr. Luke is a member of ASNE IEEE (Reliability Society) and ASQC and is an ASQC certified quality engineer and reliability engineer. Derya Alasya Jacobs:is an assistant professor in the Engineering Management Department at Old Dominion University (ODU). She has a B.S. in computer science and an M.S. and Ph.D in engineering management from the University of Missouri-Rolla. Prior to joining ODU Dr. Jacobs worked as a research engineer at the Center for Technology Transfer and Economic Development at the University of Missouri-Rolla. During the same period she served as a consultant in software development for Missouri Enterprise Rolla Missouri. Dr. Jacobs' research interests are in the areas of applied artificial intelligence decision support systems operations research and computer integrated manufacturing. Billie M. Reed:is an assistant professor in the Engineering Management Department at Old Dominion University. He received a B.S. degree in mechanical engineering from Auburn University in 1971. After completing undergraduate studies Dr. Reed was commissioned as an officer in the U.S. Navy where he served in the nuclear submarine force until 1982. Following his military career Dr. Reed worked for nine years as a systems engineer and human-machine interface designer of complex interactive computer based systems for use in aircraft space and ship systems. He received his M.S. and Ph

As technology advances and our dependency on software increases, the requirement to develop the correct means to improve quality in both the deveiopment phase and the maintenance phase of software life cycle support becomes increasingly significant. The focus of this paper is on the dilemma facing software engineering in maintaining quality within the constraints of the maintenance phase. The paper further proposes that the software maintenance process can also be analvzed and improved using statistical process control (SPC) techniques. The methods discussed in this paper have been proposed for use in the software Maintenance project at NUWC Detachment Norfolk. Upon successful testing at NUWC Detachment Norfolk, they will be forwarded to the AN/SQQ-89(V) (interagencv) software Quality Evaluation Committee for use by other agencies which are developing and maintaining AN/SQQ-89(V) software.

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