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1

Towards secure dataflow processing in open distributed systems  

Microsoft Academic Search

Open distributed systems such as service oriented architecture and cloud computing have emerged as promising platforms to deliver software as a service to users. However, for many security sen- sitive applications such as critical data processing, trus t manage- ment poses significant challenges for migrating those criti cal ap- plications into open distributed systems. In this paper, we present the

Juan Du; Wei Wei; Xiaohui Gu; Ting Yu

2009-01-01

2

Supporting Continuous Media in Open Distributed Systems Architectures  

Microsoft Academic Search

Recent developments in high-speed networks and high- performance workstations have led to the emergence of a new class of applications termed distributed multimedia applications. However, the range of distributed systems architectures currently being proposed to support open systems integration were largely conceived prior to these developments. Initial work directed towards the introduction of multimedia in environments compatible with ISO's Open

Phil Adcock; Nigel Davies; Gordon S. Blair

1993-01-01

3

Specifications for a voice/open data cable distribution system.  

National Technical Information Service (NTIS)

This report describes standard design criteria for and intrabuilding and interbuilding telecommunications wiring system to provide voice and open data services to facilities at Sandia National Laboratories, Albuquerque.

T. L. Bisbee

1990-01-01

4

Object-Oriented Design Pattern Approach for Modeling and Simulating Open Distributed Control System  

Microsoft Academic Search

An open distributed control system (DCS), which consists of a large number of devices and a single open network interconnecting those devices, is now used in many automation areas. One critical problem of the DCS, however, is that because there is massive traffic on the network, the system integrator must carefully tune the network traffic after the construction of the

Toyoaki Tomura; Satoshi Kanai; Kiyoshi Uehiro; Susumu Yamamoto

2001-01-01

5

FDTS for Open Distributed Systems, a Retrospective and a Prospective View.  

National Technical Information Service (NTIS)

Personal views on the development of Formal Description Techniques (FDTs) in the last ten years and some perspectives for the next ten years are presented. The statements made apply in particular for FDTs for open distributed systems. An historical overvi...

C. A. Vissers

1990-01-01

6

Developing Simulation Models of Open Distributed Control System by Using Object-Oriented Structural and Behavioral Patterns  

Microsoft Academic Search

An open distributed control system (DCS), which consists of many devices and an open network interconnecting them, is now used in many automation areas. For assuring the control performance under the heavy traffic on the network, the simulation of a DCS is strongly needed. For this purpose, we propose an object- oriented design pattern approach as a uniform, efficient and

Toyoaki Tomura; Satoshi Kanai; S. Yamamoto

2001-01-01

7

A distributed database system for sharing geological information using free and open source software  

NASA Astrophysics Data System (ADS)

Recently, geological information, such as borehole data and geological maps, and seismic, volcanic or landslide hazard maps are published on the Internet by the national government, local governments, and research institutes in Japan. Most web systems that deliver such geological information consist of a centralized database, which are located and maintained in one location. It is easier to manage the centralized database system because all data resides in a single location. However, if the database breaks, the web service will not be available. In the present study, a distributed database system has been developed to continue delivering geological information even if a database breaks. The distributed database system has an advantage that the system remains available although an individual database is down. All the software used to construct the system is free and open source software. PostgreSQL and pgpool-II are utilized to construct a distributed database. PostgreSQL is a powerful relational database management system. Pgpool-II has a function for management of multiple PostgreSQL servers. OpenLayers is used for the web map clients. Replication and Parallel query modes with pgpool-II are utilized for distribution of a database. It is possible to create a real-time backup on 2 or more PostgreSQL clusters by replication mode. If a database breaks, the backup database will works to continue delivering geological information. Data can be split among multiple servers by using parallel query mode. The rules to send partitioned data to an appropriate cluster are contained in the System Database. If large-scale data is searched, the overall execution time will be reduced. The prototype for sharing 1500 borehole data has been successfully implemented by combination of PostgreSQL and pgpool-II on Linux server. Further development and improvement of the system are necessary to manage and analyze various spatial data in addition to borehole data. This study was supported by KAKENHI (24700096, 25330134; Grant-in-Aid for Scientific Research by Japan Society for Promotion of Science).

Nemoto, T.; Masumoto, S.; Nonogaki, S.; Raghavan, V.

2013-12-01

8

The Earth System Grid Federation: An Open Infrastructure for Access to Distributed Geo-Spatial Data  

SciTech Connect

The Earth System Grid Federation (ESGF) is a multi-agency, international collaboration that aims at developing the software infrastructure needed to facilitate and empower the study of climate change on a global scale. The ESGF s architecture employs a system of geographically distributed peer nodes, which are independently administered yet united by the adoption of common federation protocols and application programming interfaces (APIs). The cornerstones of its interoperability are the peer-to-peer messaging that is continuously exchanged among all nodes in the federation; a shared architecture and API for search and discovery; and a security infrastructure based on industry standards (OpenID, SSL, GSI and SAML). The ESGF software is developed collaboratively across institutional boundaries and made available to the community as open source. It has now been adopted by multiple Earth science projects and allows access to petabytes of geophysical data, including the entire model output used for the next international assessment report on climate change (IPCC-AR5) and a suite of satellite observations (obs4MIPs) and reanalysis data sets (ANA4MIPs).

Cinquini, Luca [Jet Propulsion Laboratory, Pasadena, CA; Crichton, Daniel [Jet Propulsion Laboratory, Pasadena, CA; Miller, Neill [Argonne National Laboratory (ANL); Mattmann, Chris [Jet Propulsion Laboratory, Pasadena, CA; Harney, John F [ORNL; Shipman, Galen M [ORNL; Wang, Feiyi [ORNL; Bell, Gavin [Lawrence Livermore National Laboratory (LLNL); Drach, Bob [Lawrence Livermore National Laboratory (LLNL); Ananthakrishnan, Rachana [Argonne National Laboratory (ANL); Pascoe, Stephen [STFC Rutherford Appleton Laboratory, NCAS/BADC; Kershaw, Philip [STFC Rutherford Appleton Laboratory, NCAS/BADC; Gonzalez, Estanislao [German Climate Computing Center; Fiore, Sandro [Euro-Mediterranean Center on Climate Change; Schweitzer, Roland [Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration; Danvil, Sebastian [Institut Pierre Simon Laplace (IPSL), Des Sciences de L'Environnement; Morgan, Mark [Institut Pierre Simon Laplace (IPSL), Des Sciences de L'Environnement

2012-01-01

9

The Earth System Grid Federation: An Open Infrastructure for Access to Distributed Geospatial Data  

SciTech Connect

The Earth System Grid Federation (ESGF) is a multi-agency, international collaboration that aims at developing the software infrastructure needed to facilitate and empower the study of climate change on a global scale. The ESGF s architecture employs a system of geographically distributed peer nodes, which are independently administered yet united by the adoption of common federation protocols and application programming interfaces (APIs). The cornerstones of its interoperability are the peer-to-peer messaging that is continuously exchanged among all nodes in the federation; a shared architecture and API for search and discovery; and a security infrastructure based on industry standards (OpenID, SSL, GSI and SAML). The ESGF software is developed collaboratively across institutional boundaries and made available to the community as open source. It has now been adopted by multiple Earth science projects and allows access to petabytes of geophysical data, including the entire model output used for the next international assessment report on climate change (IPCC-AR5) and a suite of satellite observations (obs4MIPs) and reanalysis data sets (ANA4MIPs).

Ananthakrishnan, Rachana [Argonne National Laboratory (ANL); Bell, Gavin [Lawrence Livermore National Laboratory (LLNL); Cinquini, Luca [Jet Propulsion Laboratory, Pasadena, CA; Crichton, Daniel [Jet Propulsion Laboratory, Pasadena, CA; Danvil, Sebastian [Institut Pierre Simon Laplace (IPSL), Des Sciences de L'Environnement; Drach, Bob [Lawrence Livermore National Laboratory (LLNL); Fiore, Sandro [Euro-Mediterranean Center on Climate Change; Gonzalez, Estanislao [German Climate Computing Center; Harney, John F [ORNL; Mattmann, Chris [Jet Propulsion Laboratory, Pasadena, CA; Kershaw, Philip [STFC Rutherford Appleton Laboratory, NCAS/BADC; Miller, Neill [Argonne National Laboratory (ANL); Morgan, Mark [Institut Pierre Simon Laplace (IPSL), Des Sciences de L'Environnement; Pascoe, Stephen [STFC Rutherford Appleton Laboratory, NCAS/BADC; Schweitzer, Roland [Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration; Shipman, Galen M [ORNL; Wang, Feiyi [ORNL

2013-01-01

10

Selected papers from Middleware'98: The IFIP International Conference on Distributed Systems Platforms and Open Distributed Processing  

NASA Astrophysics Data System (ADS)

In recent years the distributed systems community has witnessed a growth in the number of conferences, leading to difficulties in tracking the literature and a consequent loss of awareness of work done by others in this important research domain. In an attempt to synthesize many of the smaller workshops and conferences in the field, and to bring together research communities which were becoming fragmented, IFIP staged Middleware'98: The IFIP International Conference on Distributed Systems Platforms and Open Distributed Processing. The conference was widely publicized and attracted over 150 technical submissions including 135 full paper submissions. The final programme consisted of 28 papers, giving an acceptance ratio of a little over one in five. More crucially, the programme accurately reflected the state of the art in middleware research, addressing issues such as ORB architectures, engineering of large-scale systems and multimedia. The traditional role of middleware as a point of integration and service provision was clearly intact, but the programme stressed the importance of emerging `must-have' features such as support for extensibility, mobility and quality of service. The Middleware'98 conference was held in the Lake District, UK in September 1998. Over 160 delegates made the journey to one of the UK's most beautiful regions and contributed to a lively series of presentations and debates. A permanent record of the conference, including transcripts of the panel discussions which took place, is available at: http://www.comp.lancs.ac.uk/computing/middleware98/ Based on their original reviews and the reactions of delegates to the ensuing presentations we have selected six papers from the conference for publication in this special issue of Distributed Systems Engineering. The first paper, entitled `Jonathan: an open distributed processing environment in Java', by Dumant et al describes a minimal, modular ORB framework which can be used for supporting real-time and multimedia applications. The framework provides mechanisms by which services such as CORBA ORBs can be constructed as personalities which exploit the services provided by the underlying minimal kernel. The issue of engineering ORBs is taken further in the second paper, `The implementation of a high-performance ORB over multiple network transports' by Lo and Pope. This paper is of particular interest since it presents the concrete results of running a modern ORB, i.e. omniORB2, over a range of transport mechanisms, including TCP/IP, shared memory and ATM AAL5. However, in order for middleware to progress, future platforms must tackle the issue of scalability as well as that of performance. For this reason we have included two papers, `Systems support for scalable and fault tolerant Internet services' by Chawathe and Brewer and `A scalable middleware solution for advanced wide-area Web services' by van Steen et al, which address the problems inherent in developing scalable middleware. Although the two papers focus on different problems in this area, they are both motivated by the explosion of services and information made available through the World Wide Web. Indeed, the role of the World Wide Web as a component in middleware platforms featured prominently in the conference and this is reflected in our choice of the paper by Cao et al entitled `Active Cache: caching dynamic contents on the Web'. Motivated once again by the problems of scalability, Cao et al propose a system to support the caching of dynamic documents. This is achieved by enabling small applets to be cached along with pages and run by the cache servers. The issues of security, trust and resource utilization raised by such a system are explored in detail by the authors. Finally, `Mobile Java objects' by Hayton et al considers these issues still further as part of the authors' work on adding object mobility to Java. Together, the six papers contained within this issue of Distributed Systems Engineering capture the essence of Middleware'98 and demonstrate the progress that has been made in the fi

Davies, Nigel; Raymond, Kerry; Blair, Gordon

1999-03-01

11

Distributed Information Systems  

Microsoft Academic Search

The Information Systems of the future will be distributed, heterogeneous and open. They will require the integration of five key technologies — databases, multimedia, object orientation, artificial intelligence and telecommunications. This paper explains the contribution of these technologies to the vision of the future and how they can be integrated. Key technical challenges and open research issues will be discussed.

Jane Grimson

1995-01-01

12

Open Systems (Architecture) Engineering.  

National Technical Information Service (NTIS)

Overview of this document: discussion of key open system concepts and definitions, conformance and compatibility management, open system engineering approach, open system policy, today's transition environment and open system transition process.

N. W. Kowalski

1996-01-01

13

Wigner distribution function and entropy of the damped harmonic oscillator within the theory of the open quantum systems  

NASA Technical Reports Server (NTRS)

The harmonic oscillator with dissipation is studied within the framework of the Lindblad theory for open quantum systems. By using the Wang-Uhlenbeck method, the Fokker-Planck equation, obtained from the master equation for the density operator, is solved for the Wigner distribution function, subject to either the Gaussian type or the delta-function type of initial conditions. The obtained Wigner functions are two-dimensional Gaussians with different widths. Then a closed expression for the density operator is extracted. The entropy of the system is subsequently calculated and its temporal behavior shows that this quantity relaxes to its equilibrium value.

Isar, Aurelian

1995-01-01

14

Developing Simulation Models of Open Distributed Control System - Design Concepts Based on Foundation Fieldbus  

Microsoft Academic Search

Field communication capabilities has became one of the main elements of an enterprise information system. The information generated in field devices has been mainly used for control and maintenance management. Due to the characteristic feature of distributed data transfer, which enables single field devices to execute automation tasks, and not just to generate information, they are now not 'only' sensors

L. Nagy-Kulcsar; P. Dobra; D. Moga; M. Dumitrean; N. Stroia

2006-01-01

15

CYCLADES: A Distributed System for Virtual Community Support Based on Open Archives  

Microsoft Academic Search

This paper is about support for the exchange of information and knowledge among researchers. We introduce the concepts of open archives and grey literature, which provide valuable sources for researchers who work alone. We analyse how users exchange information and knowledge and introduce communities to more adequately reflect the nature of human information and knowledge exchange. Finally, we present the

Tom Gross; Schloss Birlinghoven

2003-01-01

16

Integration of control and information systems by open autonomous decentralized system architecture and its application for distributed manufacturing system  

Microsoft Academic Search

Under severe economic situations, the computer systems of companies have to produce new products or supply new services flexibly in order to meet changing customers' demands. To realize a flexible computer system, the system should be able to expand and modify its software as well as its hardware rapidly. Moreover, companies have recently been tackling business process re-engineering (BPR) to

Hiroshi Wataya; Keijirou Hayashi; Junichi Toyouchi; Takeiki Aizono; T. Ilzuka; Satoru Shibao; Masaru Omura; Masaharu Oku

1997-01-01

17

Mapping of methane spatial distribution around biogas plant with an open-path tunable diode absorption spectroscopy scanning system  

NASA Astrophysics Data System (ADS)

An open-path tunable diode laser absorption spectroscopy (OP-TDLAS) detector was applied to detect the methane emission from a biogas plant in a dairy farm. Two OP-TDLAS scanning systems were built according to maximum likelihood with expectation minimization (MLEM) and smooth basis function minimization (SBFM) algorithms to reconstruct the two-dimensional (2-D) distribution maps. Six reconstruction maps with the resolution of 30×80 were obtained by the MLEM algorithm with "grid translation method" and three reconstruction maps were obtained by the SBFM algorithm with 2-D Gaussian model. The maximum mixing ratio in the first result was between 0.85 and 1.30 ppm, while it was between 1.14 and 1.30 ppm in the second result. The average mixing ratio in the first result was between 0.54 and 0.49 ppm, and between 0.56 and 0.65 ppm in the second result. The reconstruction results validated that the two algorithms could effectively reflect the methane mixing ratio distribution within the target area. However, with the more simple optical rays and less equipment requirements, the OP-TDLAS scanning system based on SBFM algorithm provides a useful monitoring tool of methane emissions in agricultural production.

Zhang, Shirui; Wang, Jihua; Dong, Daming; Zheng, Wengang; Zhao, Xiande

2013-02-01

18

Open-Pit Metal Mining Grounding Systems.  

National Technical Information Service (NTIS)

The performance of electrical grounding systems in open pit metal mines is evaluated using techniques that are described thoroughly. The normal electrical distribution and grounding practices used in metallic open pit mines are reviewed and compared with ...

L. A. Morley A. M. Christman

1976-01-01

19

ClosestNode.com: an open access, scalable, shared geocast service for distributed systems  

Microsoft Academic Search

ClosestNode.com is an accurate, scalable, and backwards-compatible service for mapping clients to a nearby server. It provides a DNS interface by which unmodied clients can look up a service name, and get the IP address of the closest server. A shared system for performing such a mapping amortizes the administration and im- plementation costs of proximity-based server selection. It is

Bernard Wong; Emin Gün Sirer

2006-01-01

20

[The future of telepathology. An Internet "distributed system" with "open standards"].  

PubMed

With the availability of Internet, the interest in the possibilities of telepathology has increased considerably. In the foreground is thereby the need of the non-expert to bring in the opinions of experts on morphological findings by means of a fast and simple procedure. The new telepathology system iPath is in compliance with these needs. The system is based on small, but when possible independently working modules. This concept allows a simple adaptation of the system to the individual environment of the user (e.g. for different cameras, frame-grabbers, microscope steering tables etc.) and for individual needs. iPath has been in use for 6 months with various working groups. In telepathology a distinction is made between "passive" and "active" consultations but for both forms a non-expert brings in the opinion of an expert. In an active consultation both are in direct connection with each other (orally or via a chat-function), this is however not the case with a passive consultation. An active consultation can include the interactive discussion of the expert with the non-expert on images in an image database or the direct interpretation of images from a microscope by the expert. Four software modules are available for a free and as fast as possible application: (1) the module "Microscope control", (2) the module "Connector" (insertion of images directly from the microscope without a motorized microscope), (3) the module "Client-application" via the web-browser and (4) the module "Server" with a database. The server is placed in the internet and not behind a firewall. The server permanently receives information from the periphery and returns the information to the periphery on request. The only thing which the expert, the non-expert and the microscope have to know is how contact can made with the server. PMID:12089787

Brauchli, K; Helfrich, M; Christen, H; Jundt, G; Haroske, G; Mihatsch, M; Oberli, H; Oberholzer, M

2002-05-01

21

The Open Systems University.  

ERIC Educational Resources Information Center

The purpose of this paper is focused toward a systems understanding of the contemporary university, the American University being the data base. A general systems conceptualization called the open systems university is presented. Comprehensive and generic in character, it is hoped that the theory of the open university will be viable enough to…

Counelis, James Steve

22

75 FR 56920 - Express Mail Open and Distribute and Priority Mail Open and Distribute  

Federal Register 2010, 2011, 2012, 2013

...POSTAL SERVICE 39 CFR Part 111 Express Mail Open and Distribute and Priority...257, Tag 267, or Label 257S, on all Express Mail[supreg] Open and Distribute containers...proposes to revise the service commitment for Express Mail Open and Distribute as a...

2010-09-17

23

75 FR 72686 - Express Mail Open and Distribute and Priority Mail Open and Distribute  

Federal Register 2010, 2011, 2012, 2013

...POSTAL SERVICE 39 CFR Part 111 Express Mail Open and Distribute and Priority...257, Tag 267, or Label 257S, on all Express Mail[supreg] Open and Distribute containers...also revising the service commitment for Express Mail Open and Distribute as a...

2010-11-26

24

Open Clients for Distributed Databases  

NASA Astrophysics Data System (ADS)

We are actively developing a collection of open source example clients that demonstrate use of our "back end" data management infrastructure. The data management system is reported elsewhere at this meeting (Arko and Chayes: A Scaleable Database Infrastructure). In addition to their primary goal of being examples for others to build upon, some of these clients may have limited utility in them selves. More information about the clients and the data infrastructure is available on line at http://data.ldeo.columbia.edu. The available examples to be demonstrated include several web-based clients including those developed for the Community Review System of the Digital Library for Earth System Education, a real-time watch standers log book, an offline interface to use log book entries, a simple client to search on multibeam metadata and others are Internet enabled and generally web-based front ends that support searches against one or more relational databases using industry standard SQL queries. In addition to the web based clients, simple SQL searches from within Excel and similar applications will be demonstrated. By defining, documenting and publishing a clear interface to the fully searchable databases, it becomes relatively easy to construct client interfaces that are optimized for specific applications in comparison to building a monolithic data and user interface system.

Chayes, D. N.; Arko, R. A.

2001-12-01

25

The V distributed system  

Microsoft Academic Search

The V distributed System was developed at Stanford University as part of a research project to explore issues in distributed systems. Aspects of the design suggest important directions for the design of future operating systems and communication systems.

David R. Cheriton

1988-01-01

26

SHOMAR: An Open Architecture for Distributed Intrusion Detection Services  

Microsoft Academic Search

Distributed Intrusion Detection Systems (DIDS) offer an alternative to centralized intrusion de- tection. Current research indicates that a distributed intrusion detection paradigm may afford greater coverage, consequently providing an increase in security. In some cases, DIDS offer an alternative to centralized analysis, consequently improving scalabity. SHOMAR, the distributed architecture presented in this paper, provides an open framework that enables secure

Jeffrey Undercoffer; Filip Perich; Charles Nicholas

27

Income distribution, factor endowments, and trade openness  

Microsoft Academic Search

This paper studies the empirical links among factor endowments, trade and personal income distribution. By using panel data, we show that land and capital intensive countries have a less equal income distribution while skill intensive countries have a more equal income distribution. We also show that the effects of trade openness on inequality depend on factor endowments in a way

Antonio Spilimbergo; Juan Luis Londoño; Miguel Székely

1999-01-01

28

Authentification for Distributed Systems  

Microsoft Academic Search

A fundamental concern in building a secure distributed system is authentication of local and remote en- tities in the system. We survey authentication issues in distributed system design. Two basic paradigms underlying the design of authentication protocols are presented. We then propose an authentication framework that can be used for designing secure distributed systems, including specific protocols for secure bootstrapping,

Thomas Y. C. Woo; Simon S. Lam

1992-01-01

29

Distributed operating systems  

Microsoft Academic Search

Distributed operating systems have many aspects in common with centralized ones, but they also differ in certain ways. This paper is intended as an introduction to distributed operating systems, and especially to current university research about them. After a discussion of what constitutes a distributed operating system and how it is distinguished from a computer network, various key design issues

Andrew S. Tanenbaum; Robbert Van Renesse

1985-01-01

30

FRIB cryogenic distribution system  

SciTech Connect

The Michigan State University Facility for Rare Isotope Beams (MSU-FRIB) helium distribution system has been revised to include bayonet/warm valve type disconnects between each cryomodule and the transfer line distribution system, similar to the Thomas Jefferson National Accelerator Facility (JLab) and the Spallation Neutron Source (SNS) cryogenic distribution systems. The heat loads at various temperature levels and some of the features in the design of the distribution system are outlined. The present status, the plans for fabrication, and the procurement approach for the helium distribution system are also included.

Ganni, Venkatarao [JLAB; Dixon, Kelly D. [JLAB; Laverdure, Nathaniel A. [JLAB; Knudsen, Peter N. [JLAB; Arenius, Dana M. [JLAB; Barrios, Matthew N. [Michigan State; Jones, S. [Michigan State; Johnson, M. [Michigan State; Casagrande, Fabio [Michigan State

2014-01-01

31

Distributed System Control.  

National Technical Information Service (NTIS)

Global control in distributed systems had not been well researched. Control had only been addressed in a limited manner, such as for data-update consistency in distributed, redundant databases or for confidentiality controls (access control authentication...

J. A. Berea B. Bhangava T. Geigel K. Kim J. Kim

1997-01-01

32

Open system environment procurement  

NASA Technical Reports Server (NTRS)

Relationships between the request for procurement (RFP) process and open system environment (OSE) standards are described. A guide was prepared to help Federal agency personnel overcome problems in writing an adequate statement of work and developing realistic evaluation criteria when transitioning to an OSE. The guide contains appropriate decision points and transition strategies for developing applications that are affordable, scalable and interoperable across a broad range of computing environments. While useful, the guide does not eliminate the requirement that agencies posses in-depth expertise in software development, communications, and database technology in order to evaluate open systems.

Fisher, Gary

1994-01-01

33

Designing Distributed Learning Systems.  

ERIC Educational Resources Information Center

Increasingly, higher education institutions and businesses are developing distributed learning systems to provide continuing job-related and professional education. Principles and examples of distributed learning and support systems that promote individual development are outlined, considering issues of motivation, speed of program development,…

Campbell, J. Olin; Bourne, John

1997-01-01

34

Hadoop distributed file system for the Grid  

Microsoft Academic Search

Data distribution, storage and access are essential to CPU-intensive and data-intensive high performance Grid computing. A newly emerged file system, Hadoop distributed file system (HDFS), is deployed and tested within the Open Science Grid (OSG) middleware stack. Efforts have been taken to integrate HDFS with other Grid tools to build a complete service framework for the Storage Element (SE). Scalability

G. Attebury; A. Baranovski; K. Bloom; B. Bockelman; D. Kcira; J. Letts; T. Levshina; C. Lundestedt; T. Martin; W. Maier; Haifeng Pi; A. Rana; I. Sfiligoi; A. Sim; M. Thomas; F. Wuerthwein

2009-01-01

35

Cooling water distribution system  

DOEpatents

A passive containment cooling system for a nuclear reactor containment vessel. Disclosed is a cooling water distribution system for introducing cooling water by gravity uniformly over the outer surface of a steel containment vessel using an interconnected series of radial guide elements, a plurality of circumferential collector elements and collector boxes to collect and feed the cooling water into distribution channels extending along the curved surface of the steel containment vessel. The cooling water is uniformly distributed over the curved surface by a plurality of weirs in the distribution channels.

Orr, Richard (Pittsburgh, PA)

1994-01-01

36

Autoconfigurable distributed control systems  

Microsoft Academic Search

This paper discusses ongoing research on automatically configurable distributed control systems. We are investigating the use of networks of relatively small controllers that contain intelligence and communication capabilities to perform factory automation. These systems are expected to be more robust, adaptable and flexible than conventional designs. To achieve these benefits, fundamental changes in the underlying control system architecture are needed.

J. Agre; L. Clare; J. Lee; B. Brandin; J. Hoskins; M. Perrone

1995-01-01

37

Distribution system simulator  

NASA Technical Reports Server (NTRS)

In a series of tests performed under the Department of Energy auspices, power line carrier propagation was observed to be anomalous under certain circumstances. To investigate the cause, a distribution system simulator was constructed. The simulator was a physical simulator that accurately represented the distribution system from below power frequency to above 50 kHz. Effects such as phase-to-phase coupling and skin effect were modeled. Construction details of the simulator, and experimental results from its use are presented.

Bahrami, K. A.; Kirkham, H.; Rahman, S.

1986-01-01

38

Open high speed bus for microcomputer system  

US Patent & Trademark Office Database

An open high-speed local system bus for a microcomputer system which is decoupled from I/O and provides a consistent interface to the CPU subsystem, memory subsystem, graphics subsystem and peripheral subsystem. The local system bus supports discrete and burst transactions, pipelining in both the transactions, multiple microprocessor and distributed interrupts.

1996-05-14

39

DIstributed VIRtual System (DIVIRS) project  

NASA Technical Reports Server (NTRS)

As outlined in our continuation proposal 92-ISI-. OR (revised) on NASA cooperative agreement NCC2-539, we are (1) developing software, including a system manager and a job manager, that will manage available resources and that will enable programmers to develop and execute parallel applications in terms of a virtual configuration of processors, hiding the mapping to physical nodes; (2) developing communications routines that support the abstractions implemented in item one; (3) continuing the development of file and information systems based on the Virtual System Model; and (4) incorporating appropriate security measures to allow the mechanisms developed in items 1 through 3 to be used on an open network. The goal throughout our work is to provide a uniform model that can be applied to both parallel and distributed systems. We believe that multiprocessor systems should exist in the context of distributed systems, allowing them to be more easily shared by those that need them. Our work provides the mechanisms through which nodes on multiprocessors are allocated to jobs running within the distributed system and the mechanisms through which files needed by those jobs can be located and accessed.

Schorr, Herbert; Neuman, B. Clifford

1994-01-01

40

DIstributed VIRtual System (DIVIRS) project  

NASA Technical Reports Server (NTRS)

As outlined in our continuation proposal 92-ISI-50R (revised) on NASA cooperative agreement NCC2-539, we are (1) developing software, including a system manager and a job manager, that will manage available resources and that will enable programmers to develop and execute parallel applications in terms of a virtual configuration of processors, hiding the mapping to physical nodes; (2) developing communications routines that support the abstractions implemented in item one; (3) continuing the development of file and information systems based on the Virtual System Model; and (4) incorporating appropriate security measures to allow the mechanisms developed in items 1 through 3 to be used on an open network. The goal throughout our work is to provide a uniform model that can be applied to both parallel and distributed systems. We believe that multiprocessor systems should exist in the context of distributed systems, allowing them to be more easily shared by those that need them. Our work provides the mechanisms through which nodes on multiprocessors are allocated to jobs running within the distributed system and the mechanisms through which files needed by those jobs can be located and accessed.

Schorr, Herbert; Neuman, Clifford B.

1995-01-01

41

Distributed Virtual System (DIVIRS) project  

NASA Technical Reports Server (NTRS)

As outlined in the continuation proposal 92-ISI-50R (revised) on NASA cooperative agreement NCC 2-539, the investigators are developing software, including a system manager and a job manager, that will manage available resources and that will enable programmers to develop and execute parallel applications in terms of a virtual configuration of processors, hiding the mapping to physical nodes; developing communications routines that support the abstractions implemented; continuing the development of file and information systems based on the Virtual System Model; and incorporating appropriate security measures to allow the mechanisms developed to be used on an open network. The goal throughout the work is to provide a uniform model that can be applied to both parallel and distributed systems. The authors believe that multiprocessor systems should exist in the context of distributed systems, allowing them to be more easily shared by those that need them. The work provides the mechanisms through which nodes on multiprocessors are allocated to jobs running within the distributed system and the mechanisms through which files needed by those jobs can be located and accessed.

Schorr, Herbert; Neuman, B. Clifford

1993-01-01

42

Distributed Virtual System (DIVIRS) Project  

NASA Technical Reports Server (NTRS)

As outlined in our continuation proposal 92-ISI-50R (revised) on contract NCC 2-539, we are (1) developing software, including a system manager and a job manager, that will manage available resources and that will enable programmers to program parallel applications in terms of a virtual configuration of processors, hiding the mapping to physical nodes; (2) developing communications routines that support the abstractions implemented in item one; (3) continuing the development of file and information systems based on the virtual system model; and (4) incorporating appropriate security measures to allow the mechanisms developed in items 1 through 3 to be used on an open network. The goal throughout our work is to provide a uniform model that can be applied to both parallel and distributed systems. We believe that multiprocessor systems should exist in the context of distributed systems, allowing them to be more easily shared by those that need them. Our work provides the mechanisms through which nodes on multiprocessors are allocated to jobs running within the distributed system and the mechanisms through which files needed by those jobs can be located and accessed.

Schorr, Herbert; Neuman, B. Clifford

1993-01-01

43

Secure software distribution system  

SciTech Connect

Authenticating and upgrading system software plays a critical role in information security, yet practical tools for assessing and installing software are lacking in today`s marketplace. The Secure Software Distribution System (SSDS) will provide automated analysis, notification, distribution, and installation of security patches and related software to network-based computer systems in a vendor-independent fashion. SSDS will assist with the authentication of software by comparing the system`s objects with the patch`s objects. SSDS will monitor vendor`s patch sites to determine when new patches are released and will upgrade system software on target systems automatically. This paper describes the design of SSDS. Motivations behind the project, the advantages of SSDS over existing tools as well as the current status of the project are also discussed. 2 figs.

Bartoletti, T.; Dobbs, L.A.; Kelley, M.

1997-02-01

44

Minimum Loss Configuration of Power Distribution System  

Microsoft Academic Search

This paper presents a new method for minimum loss reconfiguration for radial power distribution system, in which the choice of the switches to be opened \\/ closed is based on the calculation of voltage at the buses, real and reactive power flowing through lines, real power losses and voltage deviation, using distribution load flow (DLF) program. In the process of

Jaswanti; T. Thakur

2006-01-01

45

Investigation of physicochemical characteristics and heavy metal distribution profile in groundwater system around the open dump site  

NASA Astrophysics Data System (ADS)

In this study, the characterization of solid waste and the effect of the leachate from an open dumping site in Ariyamangalam, Tiruchirappalli District, Tamil Nadu, on groundwater is investigated. A total of 14 groundwater samples and 20 leachate samples were collected for monitoring purpose. All the samples were analyzed for various physical and chemical parameters according to standard methods: this includes pH, electrical conductivity, total dissolved solids (TDS), total hardness, and total alkalinity, major cations such as Ca2+, Mg2+, and Fe2+, major anions such as NO3 -, Cl-, and SO4 2- and heavy metals such as Cd, Cu, Mn, Pb, and Zn. The results indicated that, very few parameters such as pH, sulfates and nitrates concentration in the groundwater samples are within the recommended maximum admissible limits approved by WHO (World Health Organization 940-949, 2002) and Bureau of Indian standards (IS 10500:1991). The TDS (range between 740 and 14,200 mg/L) in groundwater reveal the saline behavior of water and was found to be very high according to standards. The range of chlorides in all the locations under investigation is 215.15-4,098.73 mg/L. The contour plots also indicated that the groundwater was rigorously contaminated with various heavy metals. The presence of high concentration of Pb (0.59 mg/L) in groundwater samples nearby dumping site implies that groundwater samples were contaminated by leachate migration from an open dumping site.

Kanmani, S.; Gandhimathi, R.

2013-06-01

46

Open Systems Approach to Supportability.  

National Technical Information Service (NTIS)

The open systems approach is both a technical approach to weapons systems engineering and a preferred business strategy that is becoming widely applied by manufacturers of large complex systems. Today, legacy systems continue to be developed with their ow...

A. G. Larson C. K. Banning J. F. Leonard

2002-01-01

47

75 FR 4741 - Express Mail Open and Distribute and Priority Mail Open and Distribute Changes and Updates  

Federal Register 2010, 2011, 2012, 2013

...POSTAL SERVICE 39 CFR Part 111 Express Mail Open and Distribute and Priority...standards to reflect changes and updates for Express Mail[supreg] Open and Distribute and...INFORMATION: The Open and Distribute feature of Express Mail and Priority Mail service...

2010-01-29

48

75 FR 14076 - Express Mail Open and Distribute and Priority Mail Open and Distribute Changes and Updates  

Federal Register 2010, 2011, 2012, 2013

...POSTAL SERVICE 39 CFR Part 111 Express Mail Open and Distribute and Priority...16 to reflect changes and updates for Express Mail[supreg] Open and Distribute and...a revision to change the standards for Express Mail Open and Distribute and...

2010-03-24

49

Factors Affecting Distributed System Security.  

National Technical Information Service (NTIS)

Recent work examining distributed system security requirements is critiqued. A notion of trust based on distributed system topology and distributed system node evaluation levels proposed in that work is shown to be deficient. The notion fails to make allo...

D. M. Nessett

1985-01-01

50

Symmetry in distributed systems  

SciTech Connect

A distributed computing system can be considered to be symmetric because of its topology or because of its behavior. Unfortunately, these different definitions can categorize the same system differently. The choice of definition becomes important when one is trying to prove that certain problems, such as the Dining Philosophers problem, cannot be solved on symmetric distributed computing systems. Since the behavioral definitions are based on the possible patterns of computation, it is much easier to use them for these proofs. However, behavioral definitions frequently are undecidable; topological definitions admit straightforward decision procedures. This thesis presents a new definition for symmetry, called similarity, that, while based on behavior of processes, is decidable given the initial configuration of the system. The decision procedure for similarity depends partly on the model of computation being used, but a way to discover these decision procedures is given and is used to find decision procedures for a wide range of models of distributed computation. Distributed versions of these decision procedures form the basis of solutions to the problem of selecting a process as the leader. The thesis also shows how to use similarity to compare the relative power of different models of computation.

Johnson, R.E.

1987-01-01

51

Planning for Distributed Systems.  

ERIC Educational Resources Information Center

Reasons for distributed systems (DS) of planning and design for information services for colleges are discussed. The methodologies and approaches from industry and academe are contrasted to show how the process of DS can be effectively managed to meet a variety of institutional needs. DS represent a natural evolution of the historic development of…

Chew, Robert L.

52

Distributed Transaction Processing in the TUXEDO System  

Microsoft Academic Search

The TUXEDO system, a commercially proven transaction monitor, built on open industry standards, is described. It ensures data integrity in a distributed, heterogeneous environment with an optimized two-phase commit protocol. It offers an advanced client\\/server programming paradigm, increased throughput, network connectivity, and runtime system monitoring and management

Edward P. Felt

1993-01-01

53

Pade spectrum decompositions of quantum distribution functions and optimal hierarchical equations of motion construction for quantum open systems  

SciTech Connect

Pade spectrum decomposition is an optimal sum-over-poles expansion scheme of Fermi function and Bose function [J. Hu, R. X. Xu, and Y. J. Yan, J. Chem. Phys. 133, 101106 (2010)]. In this work, we report two additional members to this family, from which the best among all sum-over-poles methods could be chosen for different cases of application. Methods are developed for determining these three Pade spectrum decomposition expansions at machine precision via simple algorithms. We exemplify the applications of present development with optimal construction of hierarchical equations-of-motion formulations for nonperturbative quantum dissipation and quantum transport dynamics. Numerical demonstrations are given for two systems. One is the transient transport current to an interacting quantum-dots system, together with the involved high-order co-tunneling dynamics. Another is the non-Markovian dynamics of a spin-boson system.

Hu Jie; Luo Meng; Jiang Feng [Department of Chemistry, Hong Kong University of Science and Technology, Kowloon (Hong Kong); Xu Ruixue [Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Yan Yijing [Department of Chemistry, Hong Kong University of Science and Technology, Kowloon (Hong Kong); Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2011-06-28

54

Pade? spectrum decompositions of quantum distribution functions and optimal hierarchical equations of motion construction for quantum open systems.  

PubMed

Pade? spectrum decomposition is an optimal sum-over-poles expansion scheme of Fermi function and Bose function [J. Hu, R. X. Xu, and Y. J. Yan, J. Chem. Phys. 133, 101106 (2010)]. In this work, we report two additional members to this family, from which the best among all sum-over-poles methods could be chosen for different cases of application. Methods are developed for determining these three Pade? spectrum decomposition expansions at machine precision via simple algorithms. We exemplify the applications of present development with optimal construction of hierarchical equations-of-motion formulations for nonperturbative quantum dissipation and quantum transport dynamics. Numerical demonstrations are given for two systems. One is the transient transport current to an interacting quantum-dots system, together with the involved high-order co-tunneling dynamics. Another is the non-Markovian dynamics of a spin-boson system. PMID:21721611

Hu, Jie; Luo, Meng; Jiang, Feng; Xu, Rui-Xue; Yan, Yijing

2011-06-28

55

Consumer products distribution system  

US Patent & Trademark Office Database

A real-time transaction processing Consumer Products Distribution System (PDMS) reduces distribution costs, facilitates the distribution of products to consumers and makes online shopping practical. The PDMS integrates Collaborative Inventory Sharing, Order Aggregation, Consumer Predictive Purchasing, Product Transport Support Service, Display Shops, Uniform Consumer Preference Codes, Integrated Virtual Technical Support Centers, and other convenient features. Consumers purchase products through web sites of local and remotely located retailers preferably using Predictive Purchasing. The items purchased from multiple retailers are aggregated at a consumer selected Order Aggregation Site (OAS) based upon a consumer specified schedule. The consumer can pick up the aggregated orders at the selected OAS or have the aggregated orders delivered to a residence. Commercial carriers process consumer parcels at OASs where they are combined with Aggregated Orders for pickup or delivery. Consumers are given incentive discounts to promote the use of Predictive Purchasing, which significantly improves supply chain productivity.

2007-08-14

56

Distributed spot pricing in radial distribution systems  

Microsoft Academic Search

Spot pricing is a method for pricing electricity that maximizes the economic efficiency of the power system. The authors derive an expression for the spot prices in a radial distribution system, in terms of system quantities such as power line flows. The system's radial structure leads to simplified spot price expressions. They do not assume that all the problem data

L. Murphy; R. J. Kaye; F. F. Wu

1994-01-01

57

Distributed Deliberative Recommender Systems  

NASA Astrophysics Data System (ADS)

Case-Based Reasoning (CBR) is one of most successful applied AI technologies of recent years. Although many CBR systems reason locally on a previous experience base to solve new problems, in this paper we focus on distributed retrieval processes working on a network of collaborating CBR systems. In such systems, each node in a network of CBR agents collaborates, arguments and counterarguments its local results with other nodes to improve the performance of the system's global response. We describe D2ISCO: a framework to design and implement deliberative and collaborative CBR systems that is integrated as a part of jcolibritwo an established framework in the CBR community. We apply D2ISCO to one particular simplified type of CBR systems: recommender systems. We perform a first case study for a collaborative music recommender system and present the results of an experiment of the accuracy of the system results using a fuzzy version of the argumentation system AMAL and a network topology based on a social network. Besides individual recommendation we also discuss how D2ISCO can be used to improve recommendations to groups and we present a second case of study based on the movie recommendation domain with heterogeneous groups according to the group personality composition and a group topology based on a social network.

Recio-García, Juan A.; Díaz-Agudo, Belén; González-Sanz, Sergio; Sanchez, Lara Quijano

58

Distribution system reliability indices  

SciTech Connect

Distribution system reliability assessment can be divided into two basic segments of measuring past performance and predicting future performance. This paper compares the results obtained from tow surveys dealing with United States and Canadian utility activities in regard to service continuity data collection and utilization. The paper also presents a summary of service continuity statistics for those Canadian utilities that participate in the Canadian Electrical Association annual service continuity reports.

Billinton, R.; Billinton, J.E.

1989-01-01

59

The Distributed Annotation System  

Microsoft Academic Search

BackgroundCurrently, most genome annotation is curated by centralized groups with limitedresources. Efforts to share annotations transparently among multiple groups have not yet beensatisfactory.ResultsHere we introduce a concept called the Distributed Annotation System (DAS). DASallows sequence annotations to be decentralized among multiple third-party annotators andintegrated on an as-needed basis by client-side software. The communication between clientand servers in DAS is...

Robin D. Dowell; Rodney M. Jokerst; Allen Day; Sean R. Eddy; Lincoln Stein

2001-01-01

60

Federal Open Agent System Platform  

Microsoft Academic Search

Open Agent System platform based on High Level Architecture is firstly proposed to support the application involving heterogeneous agents. The basic idea is to develop different wrappers for different agent systems, which are wrapped as federates to join a federation. The platform is based on High Level Architecture and the advantages for this open standard are naturally inherited, such as

Hong-Bing Wang; Zhi-Hua Fan; Chun-Dong She

2006-01-01

61

Share Scheduling in Distributed Systems.  

National Technical Information Service (NTIS)

A distributed system is a collection of cooperating computers. In the past two decades, the use of distributed systems has increased dramatically. Such systems have several advantages over uniprocessors, such as improved performance and increased fault to...

J. F. C. M. DeJongh

2002-01-01

62

Emerging Trends in the Food Distribution System  

Microsoft Academic Search

Two trends, the drive for differentiation and the clamor for collaboration, are emerging from intermediaries in the food distribution system. Differentiation by large manufacturers and retailers will encourage more direct marketing by farmers. Although differentiation by manufacturers creates entry barriers for small firms, differentiation by retailers may open opportunities. Some collaboration initiatives will increase the supply chain efficiency up to

Ronald B. Larson

2003-01-01

63

Quality monitored distributed voting system  

DOEpatents

A quality monitoring system can detect certain system faults and fraud attempts in a distributed voting system. The system uses decoy voters to cast predetermined check ballots. Absent check ballots can indicate system faults. Altered check ballots can indicate attempts at counterfeiting votes. The system can also cast check ballots at predetermined times to provide another check on the distributed voting system.

Skogmo, David (Albuquerque, NM)

1997-01-01

64

Quality monitored distributed voting system  

DOEpatents

A quality monitoring system can detect certain system faults and fraud attempts in a distributed voting system. The system uses decoy voters to cast predetermined check ballots. Absent check ballots can indicate system faults. Altered check ballots can indicate attempts at counterfeiting votes. The system can also cast check ballots at predetermined times to provide another check on the distributed voting system. 6 figs.

Skogmo, D.

1997-03-18

65

The Distributed Annotation System  

PubMed Central

Background Currently, most genome annotation is curated by centralized groups with limited resources. Efforts to share annotations transparently among multiple groups have not yet been satisfactory. Results Here we introduce a concept called the Distributed Annotation System (DAS). DAS allows sequence annotations to be decentralized among multiple third-party annotators and integrated on an as-needed basis by client-side software. The communication between client and servers in DAS is defined by the DAS XML specification. Annotations are displayed in layers, one per server. Any client or server adhering to the DAS XML specification can participate in the system; we describe a simple prototype client and server example. Conclusions The DAS specification is being used experimentally by Ensembl, WormBase, and the Berkeley Drosophila Genome Project. Continued success will depend on the readiness of the research community to adopt DAS and provide annotations. All components are freely available from the project website .

Dowell, Robin D; Jokerst, Rodney M; Day, Allen; Eddy, Sean R; Stein, Lincoln

2001-01-01

66

Open source portal to distributed image repositories  

NASA Astrophysics Data System (ADS)

In large institution PACS, patient data may often reside in multiple separate systems. While most systems tend to be DICOM compliant, none of them offer the flexibility of seamless integration of multiple DICOM sources through a single access point. We developed a generic portal system with a web-based interactive front-end as well as an application programming interface (API) that allows both web users and client applications to query and retrieve image data from multiple DICOM sources. A set of software tools was developed to allow accessing several DICOM archives through a single point of access. An interactive web-based front-end allows user to search image data seamlessly from the different archives and display the results or route the image data to another DICOM compliant destination. An XML-based API allows other software programs to easily benefit from this portal to query and retrieve image data as well. Various techniques are employed to minimize the performance overhead inherent in the DICOM. The system is integrated with a hospital-wide HIPAA-compliant authentication and auditing service that provides centralized management of access to patient medical records. The system is provided under open source free licensing and developed using open-source components (Apache Tomcat for web server, MySQL for database, OJB for object/relational data mapping etc.). The portal paradigm offers a convenient and effective solution for accessing multiple image data sources in a given healthcare enterprise and can easily be extended to multi-institution through appropriate security and encryption mechanisms.

Tao, Wenchao; Ratib, Osman M.; Kho, Hwa; Hsu, Yung-Chao; Wang, Cun; Lee, Cason; McCoy, J. M.

2004-04-01

67

Technology Assessment of Distributed Systems.  

National Technical Information Service (NTIS)

There are multiple advantages to configuring the available resources as distributed system as opposed to a simple network. Performance is improved with a distributed system since the storage space, processors, and communications devices are equally loaded...

1989-01-01

68

Process evaluation distributed system  

NASA Technical Reports Server (NTRS)

The distributed system includes a database server, an administration module, a process evaluation module, and a data display module. The administration module is in communication with the database server for providing observation criteria information to the database server. The process evaluation module is in communication with the database server for obtaining the observation criteria information from the database server and collecting process data based on the observation criteria information. The process evaluation module utilizes a personal digital assistant (PDA). A data display module in communication with the database server, including a website for viewing collected process data in a desired metrics form, the data display module also for providing desired editing and modification of the collected process data. The connectivity established by the database server to the administration module, the process evaluation module, and the data display module, minimizes the requirement for manual input of the collected process data.

Moffatt, Christopher L. (Inventor)

2006-01-01

69

Systems architecture for distributed applications  

NASA Technical Reports Server (NTRS)

This paper describes the kernel of a distributed operating system called ADAPT. The system runs on top of existing single host operating systems that are networked together. It's purpose is to transform this network of individual systems into a single system that will be easier for application programmers to use. This single system need not be monolithic; ADAPT facilitates the construction of both integrated and modular distributed systems.

Peebles, R.

1980-01-01

70

Dynamics of explosive paroxysms at open andesitic systems: high-resolution mass distribution analyses of 2006 tephra from Tungurahua volcano (Ecuador)  

NASA Astrophysics Data System (ADS)

Many andesitic volcanoes at subduction plate margins can experience in the course of their evolution periods of sub-continuous eruption during years, decades, or centuries. Such long-lived periods may embrace more or less intense outgassing events, extrusion of viscous lava flows and domes (e.g. Colima in Mexico, Merapi in Indonesia, Arenal in Costa Rica), and explosive activity of uneven intensity (e.g. Semeru in Indonesia, Sakurajima in Japan, Sangay in Ecuador). In addition, strong explosive events of short duration may occur, with potential generation of pyroclastic flows on the flanks and beyond, which can pose significant hazards in populated regions. The origin and dynamics of such violent eruptions remain poorly known and may involve a combination of different factors. Tungurahua volcano, Ecuador, reawaken in 1999 and is an example of such open-system behaviour that experienced a strong and deadly andesitic pyroclastic flow-forming event in August 2006. Inspection of the deposits suggested that the event could have been triggered by magma mixing (silicic pumices in the tephra), magma-water interaction (presence of xenolithic clasts) or deep andesitic magma reinjection (based on mineral chemistry). Here we investigate these options by performing a high-resolution mass budget analysis of the scoria fall deposit. This is achieved by analysing componentry compositions and their mass distribution pattern in the layer, which allow us to document and integrate exponential and power laws mass decay rates over wide areas. The results yield a total mass for the tephra layer of ~2 x 1010kg. The pumice mass fraction is far too small (< 0.4 %) to account for the high explosivity of the 2006 event. Similarly, the xenoclastic mass fraction is small (0.2%) and suggests limited magma-water interaction. Instead, we interpret these xenoclasts as a result of upper conduit erosion at a rate of ~30 cm/hour during the paroxysm. Altogether our results support an explosive event fed by a deep gas-rich andesitic reinjection, which would have incorporated a pocket of older differentiated magma and eroded the upper conduit during the sub-plinian event. The high-resolution mass-based approach reveals useful to decipher the origin of the violent 2006 paroxysm and has potential to improve magnitude determinations of ancient eruption by considering componentry mass instead of volume. It is also applicable for monitoring purposes in the context of on-going crises at andesitic volcanoes worldwide.

Le Pennec, J.; Eychenne, J.; Ramon, P.; Yepes, H.

2012-12-01

71

Ultra Stable Frequency Distribution System.  

National Technical Information Service (NTIS)

The frequency distribution system of the present invention can be utilized for distributing a frequency standard to remotely located land based or satellite stations. A signal is synchronized at a remotely located slave station with the phase and frequenc...

R. L. Sydnor J. W. Macconnell

1976-01-01

72

DISTRIBUTION SYSTEM CONSIDERATIONS FOR TREATMENT  

EPA Science Inventory

EPA and other research has shown that drinking water distribution systems are active reactors, which can accumulate, release, or transform contaminants during passage from the treatment plant to the consumers’ taps. This presentation discusses the nature of distribution sys...

73

Integrated High Performance Distributed System.  

National Technical Information Service (NTIS)

The objective of the Integrated High Performance Distributed System (IHPDS) project is to design, implement, and demonstrate a distributed programming environment that will integrate and support very high bandwidth networks with heterogeneous computer arc...

E. F. Walker C. Barber B. Owen J. Zinky C. Howe

1994-01-01

74

Distributed simulation systems  

Microsoft Academic Search

An overview of technologies concerned with distributing the execution of simulation programs across multiple processors is presented. Here, particular emphasis is placed on discrete event simulations. The High Level Architecture (HLA) developed by the Department of Defense in the United States is first described to provide a concrete example of a contemporary approach to distributed simulation. The remainder of this

Richard M. Fujimoto

2003-01-01

75

Open Systems and Citizenship: Designing a Departmental Web Site as an Open System.  

ERIC Educational Resources Information Center

Describes how members of the English Department at Texas Tech University redesigned their site as an open system in which control is distributed among department members. Describes the conversational approach they used to redesign the site, applies it to a critique of the original web site, then describes changes they implemented to remake the…

Spinuzzi, Clay; Bowie, Jennifer L.; Rodgers, Ida; Li, Xiangyi

2003-01-01

76

Wireless distributed functional electrical stimulation system  

PubMed Central

Background The control of movement in humans is hierarchical and distributed and uses feedback. An assistive system could be best integrated into the therapy of a human with a central nervous system lesion if the system is controlled in a similar manner. Here, we present a novel wireless architecture and routing protocol for a distributed functional electrical stimulation system that enables control of movement. Methods The new system comprises a set of miniature battery-powered devices with stimulating and sensing functionality mounted on the body of the subject. The devices communicate wirelessly with one coordinator device, which is connected to a host computer. The control algorithm runs on the computer in open- or closed-loop form. A prototype of the system was designed using commercial, off-the-shelf components. The propagation characteristics of electromagnetic waves and the distributed nature of the system were considered during the development of a two-hop routing protocol, which was implemented in the prototype’s software. Results The outcomes of this research include a novel system architecture and routing protocol and a functional prototype based on commercial, off-the-shelf components. A proof-of-concept study was performed on a hemiplegic subject with paresis of the right arm. The subject was tasked with generating a fully functional palmar grasp (closing of the fingers). One node was used to provide this movement, while a second node controlled the activation of extensor muscles to eliminate undesired wrist flexion. The system was tested with the open- and closed-loop control algorithms. Conclusions The system fulfilled technical and application requirements. The novel communication protocol enabled reliable real-time use of the system in both closed- and open-loop forms. The testing on a patient showed that the multi-node system could operate effectively to generate functional movement.

2012-01-01

77

Concentration distribution of sediment mixtures in open-channel flow  

Microsoft Academic Search

Rouse's equation and some of the recently developed equations for concentration distribution in the case of flow in an open channel have been checked for their accuracy with the help of data ofsuspended-sediment concentration-distribution of the individual fractions in a mixture. The agreement between predictions and measurements is not found to be satisfactory. It is found that the sediment distribution

B. R. Samaga; K. G. Ranga Raju; R. J. Garde

1985-01-01

78

DNA Computing: Distributed Splicing Systems  

Microsoft Academic Search

Because splicing systems with a finite set of rules generate only regular languages, it is necessary to supplement such a system with a control mechanism on the use of rules. One fruitful idea is to use distributed architectures suggested by the grammar systems area. Three distributed computability (language generating) devices based on splicing are discussed here. First, we improve a

Gheorghe Paun

1997-01-01

79

ANN - based distribution system reconfiguration  

SciTech Connect

This paper describes an Artificial Neural Network (ANN) - based distribution system reconfiguration scheme to reduce system loss. The ANN is trained for different load levels and different network topologies. The proposed scheme has been tested using a 38 - bus distribution system. The results are very promising.

Momoh, J.A.; Wang, Yanchun [Howard Univ., Washington, DC (United States). Electrical Engineering Dept.; Rizy, D.T. [Oak Ridge National Lab., TN (United States)

1997-08-01

80

Distributed operating system for PASM  

Microsoft Academic Search

The structure of PASMOS, a distributed operating system for the PASM parallel processing system, is overviewed. PASM is a large-scale dynamically reconfigurable multi-microcomputer system which is being designed at Purdue University for image processing and pattern recognition applications. This special purpose nature of PASM has been exploited in the design of PASMOS. PASMOS has a hierarchical structure and is distributed

D. L. Tuomenoksa; H. J. Siegel

1984-01-01

81

Load Balancing in Distributed Systems  

Microsoft Academic Search

In a distributed computing system made up of different types of processors each processor in the system may have different performance and reliability characteristics. In order to take advantage of this diversity of processing power, a modular distributed program should have its modules assigned in such a way that the applicable system performance index, such as execution time or cost,

Timothy C. K. Chou; Jacob A. Abraham

1982-01-01

82

Constructing Distributed Systems in Conic  

Microsoft Academic Search

Existing distributed systems vary from those which merely provide interconnection of autonomous systems to those which provide a complete language environment for writing distributed programs. The former tend to support flexibility and provide ready access to system facilities, but suffer by being complex to use. Language environments are simpler to use and can provide safer environments by performing checks, but

Jeff Magee; Jeff Kramer; Morris Sloman

1989-01-01

83

Distributed systems status and control  

NASA Technical Reports Server (NTRS)

Concepts are investigated for an automated status and control system for a distributed processing environment. System characteristics, data requirements for health assessment, data acquisition methods, system diagnosis methods and control methods were investigated in an attempt to determine the high-level requirements for a system which can be used to assess the health of a distributed processing system and implement control procedures to maintain an accepted level of health for the system. A potential concept for automated status and control includes the use of expert system techniques to assess the health of the system, detect and diagnose faults, and initiate or recommend actions to correct the faults. Therefore, this research included the investigation of methods by which expert systems were developed for real-time environments and distributed systems. The focus is on the features required by real-time expert systems and the tools available to develop real-time expert systems.

Kreidler, David; Vickers, David

1990-01-01

84

Open Systems Deployment Plan.  

National Technical Information Service (NTIS)

Historically, many weapon systems have been developed in closed environments that do not encourage use of many Commercial Off-The-Shelf (COTS) products and/or Non-Oevelopmental Items (NDI) The use of proprietary hardware and software by systems developers...

1996-01-01

85

Standard Data Exchanges for Distribution System Management  

SciTech Connect

Databases and software tools for electric power distribution systems have not been integrated, and this leads to extra costs and restrictions imposed on utilities and other stakeholders. For example, distributed resource integration studies and modern grid technology assessments are more difficult and costly. New vendors face high market entry barriers, because it’s necessary to interface with large and customized data systems at each potential utility customer. This project promotes data and software tool integration, through a set of data translators based on a common object model. The data translators are delivered as open-source software, using appropriate Web software technologies. The parties who benefit include electric utilities (and their ratepayers), researchers at government laboratories and universities, small software companies wishing to enter the electric utility market, and parties wishing to interconnect distributed generation to a utility system.

Thomas E. McDermott

2007-10-05

86

A prototype Distributed Audit System  

SciTech Connect

Security auditing systems are used to detect and assess unauthorized or abusive system usage. Historically, security audits were confined to a single computer system. Recent work examines ways of extending auditing to include heterogeneous groups of computers (distributed system). This paper describes the design and prototype development of a Distributed Audit System (DAS) which was developed with funding received from Lawrence Livermore Laboratory and through the Master`s thesis effort performed by the author at California State University, Long Beach. The DAS is intended to provide collection, transfer, and control of audit data on distributed, heterogeneous hosts.

Banning, D.L. [Sparta, Inc., El Segundo, CA (United States)

1993-08-01

87

The DURESS project: Extending databases into an open systems architecture  

Microsoft Academic Search

The DURESS (Distributed University Research and Education and Support System) project is a joint effort of the Database and Information Systems Group at the Johann Wolfgang Goethe-University, Frankfurt, and the IBM European Networking Center, Heidelberg, West-Germany. In the DURESS project, the applicability of an integrated database and programming language is extended into an open distributed environment. The extended a chitecture

W. Johannsen; W. Lamersdorf; K. Reinhardt; J. Schmidt

88

Automated Power-Distribution System  

NASA Technical Reports Server (NTRS)

Automated power-distribution system monitors and controls electrical power to modules in network. Handles both 208-V, 20-kHz single-phase alternating current and 120- to 150-V direct current. Power distributed to load modules from power-distribution control units (PDCU's) via subsystem distributors. Ring busses carry power to PDCU's from power source. Needs minimal attention. Detects faults and also protects against them. Potential applications include autonomous land vehicles and automated industrial process systems.

Thomason, Cindy; Anderson, Paul M.; Martin, James A.

1990-01-01

89

Fieldbus based distributed control system  

Microsoft Academic Search

This paper gives a detailed description of a new design of fieldbus based distributed computer control system. The main features of the control system are the thoroughly distributed architecture, the intelligent field mounted control modules, and the two level data communication networks. The field control models composed of an embedded controller can be programmed through network using the standard IEC61131

Xing Jianchun; Wang Ping; Cheng Baoyi; Wang Shuangqing; Yang Qiliang

2004-01-01

90

Code Generation for Distributed Systems  

Microsoft Academic Search

Due to the complexity of distributed code as opposed to the easy way the corresponding designs can be described graphically, interest in code generators which create applications based on abstract system descriptions, is high. An indicator for this are the many commercial products. This paper aims at exploring the theoretical foundations of code generation for distributed systems with regard to

Markus Aleksy; Ralf Gitzel

2003-01-01

91

The LOCUS Distributed Operating System  

Microsoft Academic Search

LOCUS Is a distributed operating system which supports transparent access to data through a network wide fllesystem, permits automatic replication of storaget supports transparent distributed process execution, supplies a number of high reliability functions such as nested transactions, and is upward compatible with Unix. Partitioned operation of subnetl and their dynamic merge is also supported. The system has been operational

Bruce J. Walker; Gerald J. Popek; Robert English; Charles S. Kline; Greg Thiel

1983-01-01

92

PARALLEL AND DISTRIBUTED SIMULATION SYSTEMS  

Microsoft Academic Search

Originating from basic research conducted in the 1970's and 1980's, the parallel and distributed simulation field has ma- tured over the last few decades. Today, operational systems have been fielded for applications such as military training, analysis of communication networks, and air traffic control systems, to mention a few. This tutorial gives an overview of technologies to distribute the execution

Richard M. Fujimoto

1999-01-01

93

Optimistic recovery in distributed systems  

Microsoft Academic Search

Optimistic Recovery is a new technique supporting application-independent transparent recovery from processor failures in distributed systems. In optimistic recovery communication, computation and checkpointing proceed asynchronously. Synchronization is replaced by causal dependency tracking, which enables a posteriori reconstruction of a consistent distributed system state following a failure using process rollback and message replay.Because there is no synchronization among computation, communication, and

Robert E. Strom; Shaula Yemini

1985-01-01

94

Open System Architecture for Drives  

Microsoft Academic Search

To meet the increasing demands of drive control in machine tools it is necessary to develop new and future-oriented drive control devices. In this paper we present a new platform for an Open System Architecture for Drives. This includes the specification of necessary hard- and software interfaces for the integration of new process & drive control, monitoring, diagnosis, and service

G. Pritschow; C. Kramer

2005-01-01

95

Exploiting replication in distributed systems  

NASA Technical Reports Server (NTRS)

Techniques are examined for replicating data and execution in directly distributed systems: systems in which multiple processes interact directly with one another while continuously respecting constraints on their joint behavior. Directly distributed systems are often required to solve difficult problems, ranging from management of replicated data to dynamic reconfiguration in response to failures. It is shown that these problems reduce to more primitive, order-based consistency problems, which can be solved using primitives such as the reliable broadcast protocols. Moreover, given a system that implements reliable broadcast primitives, a flexible set of high-level tools can be provided for building a wide variety of directly distributed application programs.

Birman, Kenneth P.; Joseph, T. A.

1989-01-01

96

An Open Source Simulation System  

NASA Technical Reports Server (NTRS)

An investigation into the current state of the art of open source real time programming practices. This document includes what technologies are available, how easy is it to obtain, configure, and use them, and some performance measures done on the different systems. A matrix of vendors and their products is included as part of this investigation, but this is not an exhaustive list, and represents only a snapshot of time in a field that is changing rapidly. Specifically, there are three approaches investigated: 1. Completely open source on generic hardware, downloaded from the net. 2. Open source packaged by a vender and provided as free evaluation copy. 3. Proprietary hardware with pre-loaded proprietary source available software provided by the vender as for our evaluation.

Slack, Thomas

2005-01-01

97

Arachne Distributed Operating System.  

National Technical Information Service (NTIS)

Arachne is multicomputer operating system implemented at the University of Wisconsin that allows a network of microcomputers to cooperate to provide a general-purpose computing facility. After presenting an overview of the structure of Arachne, this paper...

R. A. Finkel M. H. Solomon

1981-01-01

98

Nonequilibrium thermodynamics for open systems  

NASA Astrophysics Data System (ADS)

We develop the general equation for the nonequilibrium reversible-irreversible coupling (GENERIC) framework of nonequilibrium thermodynamics for open systems. A clear distinction between bulk and boundary contributions to the Poisson and dissipative brackets employed to generate reversible and irreversible contributions to time evolution from energy and entropy allows us to formulate the bulk equations as well as the exchange and interaction with the environment directly. The full brackets keep all the structure and hence the predictive power of the original GENERIC for isolated systems. The straightforward procedure is illustrated for hydrodynamics of open systems. Boltzmann’s kinetic equation is discussed as a further example. In the Appendix, the thermodynamic treatment of surface excess variables at walls and their role in boundary conditions for the bulk variables is exemplified for a diffusion cell.

Öttinger, Hans Christian

2006-03-01

99

The Hadoop Distributed File System  

Microsoft Academic Search

The Hadoop Distributed File System (HDFS) is designed to store very large data sets reliably, and to stream those data sets at high bandwidth to user applications. In a large cluster, thousands of servers both host directly attached storage and execute user application tasks. By distributing storage and computation across many servers, the resource can grow with demand while remaining

Konstantin Shvachko; Hairong Kuang; Sanjay Radia; Robert Chansler

2010-01-01

100

Main Injector power distribution system  

SciTech Connect

The paper describes a new power distribution system for Fermilab's Main Injector. The system provides 13.8 kV power to Main Injector accelerator (accelerator and conventional loads) and is capable of providing power to the rest of the laboratory (backfeed system). Design criteria, and features including simulation results are given.

Cezary Jach and Daniel Wolff

2002-06-03

101

Joint Surveillance System Distributed Tracker.  

National Technical Information Service (NTIS)

The Joint Surveillance System Distributed Tracker (JDT) was designed by Hughes Aircraft Company for use in a laboratory environment in conjunction with Command and Control experiments in support of the air defense initiative. The tracker provides a live a...

R. Leckie T. P. Humiston

1990-01-01

102

Hydrogen storage and distribution systems  

Microsoft Academic Search

Hydrogen storage and transportation or distribution is closely linked together. Hydrogen can be distributed continuously in\\u000a pipelines or batch wise by ships, trucks, railway or airplanes. All batch transportation requires a storage system but also\\u000a pipelines can be used as pressure storage system. Hydrogen exhibits the highest heating value per weight of all chemical fuels.\\u000a Furthermore, hydrogen is regenerative and

Andreas Züttel

2007-01-01

103

The Raid distributed database system  

NASA Technical Reports Server (NTRS)

Raid, a robust and adaptable distributed database system for transaction processing (TP), is described. Raid is a message-passing system, with server processes on each site to manage concurrent processing, consistent replicated copies during site failures, and atomic distributed commitment. A high-level layered communications package provides a clean location-independent interface between servers. The latest design of the package delivers messages via shared memory in a configuration with several servers linked into a single process. Raid provides the infrastructure to investigate various methods for supporting reliable distributed TP. Measurements on TP and server CPU time are presented, along with data from experiments on communications software, consistent replicated copy control during site failures, and concurrent distributed checkpointing. A software tool for evaluating the implementation of TP algorithms in an operating-system kernel is proposed.

Bhargava, Bharat; Riedl, John

1989-01-01

104

Open solutions to distributed control in ground tracking stations  

NASA Technical Reports Server (NTRS)

The advent of high speed local area networks has made it possible to interconnect small, powerful computers to function together as a single large computer. Today, distributed computer systems are the new paradigm for large scale computing systems. However, the communications provided by the local area network is only one part of the solution. The services and protocols used by the application programs to communicate across the network are as indispensable as the local area network. And the selection of services and protocols that do not match the system requirements will limit the capabilities, performance, and expansion of the system. Proprietary solutions are available but are usually limited to a select set of equipment. However, there are two solutions based on 'open' standards. The question that must be answered is 'which one is the best one for my job?' This paper examines a model for tracking stations and their requirements for interprocessor communications in the next century. The model and requirements are matched with the model and services provided by the five different software architectures and supporting protocol solutions. Several key services are examined in detail to determine which services and protocols most closely match the requirements for the tracking station environment. The study reveals that the protocols are tailored to the problem domains for which they were originally designed. Further, the study reveals that the process control model is the closest match to the tracking station model.

Heuser, William Randy

1994-01-01

105

Technical architecture for RF open system realization  

Microsoft Academic Search

RF functions can be effectively realized as open systems. Application of open system architecture (OSA) principles must be done at the function level, encompassing both software and hardware. Building upon the generic open architecture foundation, the additional layers necessary for RF function realization have been defined. The RF technical architecture is described with reference model that identifies the functional partitioning

C. E. Milton; C. D. Russell; J. Schroeder

1999-01-01

106

Automated Power-Distribution System  

NASA Technical Reports Server (NTRS)

Autonomous power-distribution system includes power-control equipment and automation equipment. System automatically schedules connection of power to loads and reconfigures itself when it detects fault. Potential terrestrial applications include optimization of consumption of power in homes, power supplies for autonomous land vehicles and vessels, and power supplies for automated industrial processes.

Ashworth, Barry; Riedesel, Joel; Myers, Chris; Miller, William; Jones, Ellen F.; Freeman, Kenneth; Walsh, Richard; Walls, Bryan K.; Weeks, David J.; Bechtel, Robert T.

1992-01-01

107

How robust are distributed systems  

NASA Technical Reports Server (NTRS)

A distributed system is made up of large numbers of components operating asynchronously from one another and hence with imcomplete and inaccurate views of one another's state. Load fluctuations are common as new tasks arrive and active tasks terminate. Jointly, these aspects make it nearly impossible to arrive at detailed predictions for a system's behavior. It is important to the successful use of distributed systems in situations in which humans cannot provide the sorts of predictable realtime responsiveness of a computer, that the system be robust. The technology of today can too easily be affected by worn programs or by seemingly trivial mechanisms that, for example, can trigger stock market disasters. Inventors of a technology have an obligation to overcome flaws that can exact a human cost. A set of principles for guiding solutions to distributed computing problems is presented.

Birman, Kenneth P.

1989-01-01

108

Interoperability in Complex Distributed Systems  

Microsoft Academic Search

\\u000a Distributed systems are becoming more complex in terms of both the level of heterogeneity encountered coupled with a high\\u000a level of dynamism of such systems. Taken together, this makes it very difficult to achieve the crucial property of interoperability\\u000a that is enabling two arbitrary systems to work together relying only on their declared service specification. This chapter\\u000a examines this issue

Gordon S. Blair; Massimo Paolucci; Paul Grace; Nikolaos Georgantas

109

Maintaining consistency in distributed systems  

NASA Technical Reports Server (NTRS)

In systems designed as assemblies of independently developed components, concurrent access to data or data structures normally arises within individual programs, and is controlled using mutual exclusion constructs, such as semaphores and monitors. Where data is persistent and/or sets of operation are related to one another, transactions or linearizability may be more appropriate. Systems that incorporate cooperative styles of distributed execution often replicate or distribute data within groups of components. In these cases, group oriented consistency properties must be maintained, and tools based on the virtual synchrony execution model greatly simplify the task confronting an application developer. All three styles of distributed computing are likely to be seen in future systems - often, within the same application. This leads us to propose an integrated approach that permits applications that use virtual synchrony with concurrent objects that respect a linearizability constraint, and vice versa. Transactional subsystems are treated as a special case of linearizability.

Birman, Kenneth P.

1991-01-01

110

Stability of distributed parameter systems.  

NASA Technical Reports Server (NTRS)

A theorem is derived for the stability of solutions of general linear partial differential equations. A norm of the state space in the form of multiple integrals over the spatial domain is used for the Liapunov functional. Theorems and lemmas are also given for linear time-invariant constant coefficient distributed parameter systems, a class of nonlinear distributed parameter systems and for others with a Lure-type nonlinearity. The theorem conditions are similar to those known for corresponding ordinary differential equations but with operators replacing matrices.

Park, K. E.; Kinnen, E.

1972-01-01

111

Mobile Wave Technology for Distributed Knowledge Processing in Open Networks  

Microsoft Academic Search

A novel technology for dynamic creation and processing of arbitrary network topologies in open environments will be presented. Based on the control code mobility, the technology may provide parallel processing and inference on the deepest levels of distributed knowledge representations and may be efficiently integrated with the modern visualization techniques for direct communications with multiple users. 1 WAVE ideology of

Peter S. Sapaty

1995-01-01

112

Towards Network and Distributed System Performance Management.  

National Technical Information Service (NTIS)

Traditional performance management techniques are inadequate when applied to distributed computer systems because of essential differences between traditional and distributed systems. For example, distributed systems are connected by networks that do not ...

S. Wilbur M. Merabti

1987-01-01

113

Hydronic distribution system computer model  

SciTech Connect

A computer model of a hot-water boiler and its associated hydronic thermal distribution loop has been developed at Brookhaven National Laboratory (BNL). It is intended to be incorporated as a submodel in a comprehensive model of residential-scale thermal distribution systems developed at Lawrence Berkeley. This will give the combined model the capability of modeling forced-air and hydronic distribution systems in the same house using the same supporting software. This report describes the development of the BNL hydronics model, initial results and internal consistency checks, and its intended relationship to the LBL model. A method of interacting with the LBL model that does not require physical integration of the two codes is described. This will provide capability now, with reduced up-front cost, as long as the number of runs required is not large.

Andrews, J.W.; Strasser, J.J.

1994-10-01

114

Enhanced distributed energy resource system  

DOEpatents

A power transmission system including a direct current power source electrically connected to a conversion device for converting direct current into alternating current, a conversion device connected to a power distribution system through a junction, an energy storage device capable of producing direct current connected to a converter, where the converter, such as an insulated gate bipolar transistor, converts direct current from an energy storage device into alternating current and supplies the current to the junction and subsequently to the power distribution system. A microprocessor controller, connected to a sampling and feedback module and the converter, determines when the current load is higher than a set threshold value, requiring triggering of the converter to supply supplemental current to the power transmission system.

Atcitty, Stanley (Albuquerque, NM); Clark, Nancy H. (Corrales, NM); Boyes, John D. (Albuquerque, NM); Ranade, Satishkumar J. (Las Cruces, NM)

2007-07-03

115

Properly Understanding the Impacts of Distributed Resources on Distribution Systems  

SciTech Connect

The subject paper discusses important impacts of distributed resources on distribution networks and feeders. These include capacity, line losses, voltage regulation, and central system support (such as volt/var via central generators and substation) as the number, placement and penetration levels of distributed resources are varied. Typically, the impacts of distributed resources on the distribution system are studied by using steady-state rather than dynamic analysis tools. However, the response time and transient impacts of both system equipment (such as substation/feeder capacitors) and distributed resources needs to be taken into account and only dynamic analysis will provide the full impact results. ORNL is wrapping up a study of distributed resources interconnected to a large distribution system considering the above variables. A report of the study and its results will be condensed into a paper for this panel session. The impact of distributed resources will vary as the penetration level reaches the capacity of the distribution feeder/system. The question is how high of a penetration of distributed resource can be accommodated on the distribution feeder/system without any major changes to system operation, design and protection. The impacts most surely will vary depending upon load composition, distribution and level. Also, it is expected that various placement of distributed resources will impact the distribution system differently.

Rizy, D Tom [ORNL; Li, Fangxing [ORNL; Li, Huijuan [University of Tennessee, Knoxville (UTK); Adhikari, Sarina [ORNL; Kueck, John D [ORNL

2010-01-01

116

A Distributed Internet Caching System  

Microsoft Academic Search

This paper describes a distributed Web caching system for the Internet. In the proposed structure, every client computer in the network takes on the additional role of a cache server, serving the objects it had previously requested and received to other client computers that also request the object. A comprehensive set of protocol for the access, storage and serving function

T. T. Tay; Y. Feng; M. N. Wijeysundera

2000-01-01

117

Broadcast Protocols for Distributed Systems  

Microsoft Academic Search

An innovative approach is presented to the design of fault-tolerant distributed systems that avoids the several rounds of message exchange required by current protocols for consensus agreement. The approach is based on broadcast communication over a local area network, such as an Ethernet or a token ring, and on two novel protocols, the Transprotocol, which provides efficient reliable broadcast communication,

P. M. Melliar-smith; Louise E. Moser; Vivek Agrawala

1990-01-01

118

Fundamentals of Distributed System Observation  

Microsoft Academic Search

Merely observing activity in distributed systems is challenging: even an observer's location influences its interpretation of messages notifying it of significant events in the network. Various event timestamping mecha- nisms have been proposed to help overcome this eect. This tutorial firstly identifies those problems that may arise when relying on the arrival or- der of notifications. It then critically examines

Colin J. Fidge

1996-01-01

119

Access Control in Distributed Systems  

NSDL National Science Digital Library

Treatments of access control and authorization typically focus on individual mechanisms (access control lists, capabilities) or types of policies. This module seeks to isolate the basic concepts underlying many types of authorization in distributed systems, and then to show how this perspective can lead to more flexible and sound access-control implementations.

Reiter, Mike

2009-02-22

120

The NATO III 5 MHz distribution system  

NASA Astrophysics Data System (ADS)

A high performance 5 MHz distribution system is presented, which has extremely low phase noise and jitter characteristics to provide multiple buffered outputs. The system provides basic reference frequencies for both a transportable and fixed satellite ground station, and faults can be isolated to a modular level by observing from panel status indicators. Unique circuit design and packaging concepts are used to insure that isolation between outputs is sufficient to guarantee a phase perturbation of less than 0.0016 deg when other outputs are open circuits, short circuited or terminated in 50 ohms. Circuit design techniques include high isolation cascade amplifiers, and the use of negative feedback to stabilize system gain and minimize circuit phase noise contributions.

Vulcan, A.; Bloch, M.

121

The ATLAS distributed analysis system  

NASA Astrophysics Data System (ADS)

In the LHC operations era, analysis of the multi-petabyte ATLAS data sample by globally distributed physicists is a challenging task. To attain the required scale the ATLAS Computing Model was designed around the concept of Grid computing, realized in the Worldwide LHC Computing Grid (WLCG), the largest distributed computational resource existing in the sciences. The ATLAS experiment currently stores over 140 PB of data and runs about 140,000 concurrent jobs continuously at WLCG sites. During the first run of the LHC, the ATLAS Distributed Analysis (DA) service has operated stably and scaled as planned. More than 1600 users submitted jobs in 2012, with 2 million or more analysis jobs per week, peaking at about a million jobs per day. The system dynamically distributes popular data to expedite processing and maximally utilize resources. The reliability of the DA service is high and steadily improving; Grid sites are continually validated against a set of standard tests, and a dedicated team of expert shifters provides user support and communicates user problems to the sites. Both the user support techniques and the direct feedback of users have been effective in improving the success rate and user experience when utilizing the distributed computing environment. In this contribution a description of the main components, activities and achievements of ATLAS distributed analysis is given. Several future improvements being undertaken will be described.

Legger, F.; Atlas Collaboration

2014-06-01

122

On vertical distribution of tintinnines (Ciliata, Oligotrichida, Tintinnina) in the open waters of the South Adriatic  

Microsoft Academic Search

The vertical distribution of tintinnines was studied in the open sea of the South Adriatic at a station near the city of Dubrovnik (Station 12) in the period from 1979–1980 as well as at 11 stations during a cruise in January 1980. Samples were taken with the 53-µm Nansen type net equipped with a closing system. The hauls were taken

F. Kršini?

1982-01-01

123

Modeling Indirect Interaction in Open Computational Systems  

Microsoft Academic Search

Open systems are part of a paradigm shift from algorithmic to interactive computation. Multiagent systems in nature that exhibit emergent behavior and stigmergy offer inspiration for research in open systems and enabling technologies for collaboration. This contribution distinguishes two types of interaction, directly via messages, and indirectly via persistent observable state changes. Models of collaboration are incomplete if they fail

David Keil; Dina Q. Goldin

2003-01-01

124

Java-based Open Platform for distributed health telematics applications.  

PubMed

Within the European HARP project, a Java-based Open Platform has been specified and implemented to support trustworthy distributed applications for health. Emphasis was put on security services for enabling both communication and application security. The Open Platform is Web-based and comprises the Client environment, Web/Application server, as well as Database and Archive servers. Servlets composed and executed according to the user's authorisation create signed XML messages. From those messages, user-role-related applets are generated. The technical details of the realisation are presented. Possible future enhancements for user-centric, adaptable services based on next-generation mobile service environments are outlined. PMID:15061527

Hoepner, Petra; Eckert, Klaus-Peter

2003-01-01

125

An Open Architecture for Distributed Malware Collection and Analysis  

NASA Astrophysics Data System (ADS)

Honeynets have become an important tool for researchers and network operators. However, the lack of a unified honeynet data model has impeded their effectiveness, resulting in multiple unrelated data sources, each with its own proprietary access method and format. Moreover, the deployment and management of a honeynet is a time-consuming activity and the interpretation of collected data is far from trivial. HIVE (Honeynet Infrastructure in Virtualized Environment) is a novel highly scalable automated data collection and analysis architecture we designed. Our infrastructure is based on top of proven FLOSS (Free, Libre and Open Source) solutions, which have been extended and integrated with new tools we developed. We use virtualization to ease honeypot management and deployment, combining both high-interaction and low-interaction sensors in a common infrastructure. We also address the need for rapid comprehension and detailed data analysis by harnessing the power of a relational database system, which provides centralized storage and access to the collected data while ensuring its constant integrity. This chapter presents our malware data collection architecture, offering some insight in the structure and benefits of a distributed virtualized honeynet and its development. Finally, we present some techniques for the active monitoring of centralized botnets we integrated in HIVE, which allow us to track the menaces evolution and timely deploy effective countermeasures.

Cavalca, Davide; Goldoni, Emanuele

126

Optimal Sizing of Distributed Generation Placed on Radial Distribution Systems  

Microsoft Academic Search

Distribution network planning identifies the least cost network investment that satisfies load growth requirements without violating any system and operational constraints. Power injections from distributed generation change network power flows, modifying energy losses. Determining appropriate location and optimal size of distributed generation with respect to network configuration and load distribution in the feeder is main challenge in the changing regulatory

T. N. Shukla; S. P. Singh; V. Srinivasarao; K. B. Naik

2010-01-01

127

Distributed Computer Systems and Logistics Systems: What Do They Have in Common Besides Distribution.  

National Technical Information Service (NTIS)

Two types of systems with a distributed nature are studied: distributed computer systems and logistics systems. After discussing the nature of these types of systems the question of what makes these systems distributed is answered: various reasons for the...

L. J. N. Franken B. R. Haverkort

1993-01-01

128

From Static Distributed Systems to Dynamic Systems  

Microsoft Academic Search

Abstract A noteworthy advance in distributed computing,is due to the recent development,of peer-to-peer systems. These sys- tems are essentially dynamic,in the sense that no process can get a global knowledge,on the system structure. They mainly allow processes to look up for data that can be dy- namically added\\/suppressed in a permanently,evolving set of nodes. Although protocols have been developed for

Achour Mostéfaoui; Michel Raynal; Corentin Travers; Stacy Patterson; Divyakant Agrawal; Amr El Abbadi

2005-01-01

129

The data distribution satellite system  

NASA Technical Reports Server (NTRS)

The Data Distributed Satellite (DDS) will be capable of providing the space research community with inexpensive and easy access to space payloads and space data. Furthermore, the DDS is shown to be a natural outgrowth of advances and evolution in both NASA's Space Network and commercial satellite communications. The roadmap and timescale for this evolution is described along with key demonstrations, proof-of-concept models, and required technology development that will support the projected system evolution toward the DDS.

Bruno, Ronald C.; Weinberg, Aaron

1991-01-01

130

Distribution System Efficiency Improvement Guidebook.  

SciTech Connect

This report presents a simplified procedure for looking at a portion of a distribution system to determine the cost-effectiveness of making an investment to reduce losses. The exact calculation of losses is best done on a computer; however, many approximations have been made to simplify the calculations. The report is divided into sections dealing with conductors, transformers, modifications, reconductor, add phases, reinsulate, capacitors, economics, and examples.

United States. Bonneville Power Administration; CH2M Hill, Inc.

1981-12-01

131

Planetary Data System Distributed Inventory System.  

National Technical Information Service (NTIS)

The advent of the World Wide Web (Web) and the ability to easily put data repositories on-line has resulted in a proliferation of digital libraries. The heterogeneity of the underlying systems, the autonomy of the individual sites, and distributed nature ...

J. S. Hughes S. K. McMahon

1996-01-01

132

Two issues in the municipal ownership of electric power distribution systems. [Statistical\\/econometric scrutiny  

Microsoft Academic Search

Though municipal ownership of electric power distribution systems has been a growing public issue since the late 1960s, serious empirical econometric investigation of distribution has barely begun. The author opens with a critique of two recent works on distribution costs: one on distribution return to scale and one on comparative public\\/private efficiency. A new conceptualization of the factors influencing distribution

Neuberg

2009-01-01

133

Perturbative approach to Markovian open quantum systems.  

PubMed

The exact treatment of Markovian open quantum systems, when based on numerical diagonalization of the Liouville super-operator or averaging over quantum trajectories, is severely limited by Hilbert space size. Perturbation theory, standard in the investigation of closed quantum systems, has remained much less developed for open quantum systems where a direct application to the Lindblad master equation is desirable. We present such a perturbative treatment which will be useful for an analytical understanding of open quantum systems and for numerical calculation of system observables which would otherwise be impractical. PMID:24811607

Li, Andy C Y; Petruccione, F; Koch, Jens

2014-01-01

134

Perturbative approach to Markovian open quantum systems  

NASA Astrophysics Data System (ADS)

The exact treatment of Markovian open quantum systems, when based on numerical diagonalization of the Liouville super-operator or averaging over quantum trajectories, is severely limited by Hilbert space size. Perturbation theory, standard in the investigation of closed quantum systems, has remained much less developed for open quantum systems where a direct application to the Lindblad master equation is desirable. We present such a perturbative treatment which will be useful for an analytical understanding of open quantum systems and for numerical calculation of system observables which would otherwise be impractical.

Li, Andy C. Y.; Petruccione, F.; Koch, Jens

2014-05-01

135

Perturbative approach to Markovian open quantum systems  

PubMed Central

The exact treatment of Markovian open quantum systems, when based on numerical diagonalization of the Liouville super-operator or averaging over quantum trajectories, is severely limited by Hilbert space size. Perturbation theory, standard in the investigation of closed quantum systems, has remained much less developed for open quantum systems where a direct application to the Lindblad master equation is desirable. We present such a perturbative treatment which will be useful for an analytical understanding of open quantum systems and for numerical calculation of system observables which would otherwise be impractical.

Li, Andy C. Y.; Petruccione, F.; Koch, Jens

2014-01-01

136

Small Aircraft Data Distribution System  

NASA Technical Reports Server (NTRS)

The CARVE Small Aircraft Data Distribution System acquires the aircraft location and attitude data that is required by the various programs running on a distributed network. This system distributes the data it acquires to the data acquisition programs for inclusion in their data files. It uses UDP (User Datagram Protocol) to broadcast data over a LAN (Local Area Network) to any programs that might have a use for the data. The program is easily adaptable to acquire additional data and log that data to disk. The current version also drives displays using precision pitch and roll information to aid the pilot in maintaining a level-level attitude for radar/radiometer mapping beyond the degree available by flying visually or using a standard gyro-driven attitude indicator. The software is designed to acquire an array of data to help the mission manager make real-time decisions as to the effectiveness of the flight. This data is displayed for the mission manager and broadcast to the other experiments on the aircraft for inclusion in their data files. The program also drives real-time precision pitch and roll displays for the pilot and copilot to aid them in maintaining the desired attitude, when required, during data acquisition on mapping lines.

Chazanoff, Seth L.; Dinardo, Steven J.

2012-01-01

137

Unconventional and Innovative: The Open Croquet Project. The Systems Librarian  

ERIC Educational Resources Information Center

This brief article gives a description of the Open Croquet Project and its applications. The project's Web site describes Croquet as a "combination of computer software and network architecture that supports deep collaboration and resource sharing among large numbers of users within the context of a large-scale distributed information system." One…

Breeding, Marshall

2005-01-01

138

Application of the Open Software Foundation (OSF)distributed computing environment to global PACS  

NASA Astrophysics Data System (ADS)

In this paper, we present our approach to developing Global Picture Archiving and Communication System (GPACS) applications using the Open Software Foundation (OSF) Distributed Computing Environment (DCE) services and toolkits. The OSF DCE services include remote procedure calls, naming service, threads service, time service, file management services, and security service. Several OSF DCE toolkits are currently available from computer and software vendors. Designing distributed Global PACS applications using the OSF DCE approach will feature an open architecture, heterogeneity, and technology independence for GPACS remote consultation and diagnosis applications, including synchronized image annotation, and system privacy and security. The applications can communicate through various transport services and communications networks in a Global PACS environment. The use of OSF DCE services for Global PACS will enable us to develop a robust distributed structure and new user services which feature reliability and scalability for Global PACS environments.

Martinez, Ralph; Alsafadi, Yasser H.; Kim, Jinman

1994-05-01

139

Television Distribution System for Primary Schools.  

ERIC Educational Resources Information Center

This report covers a 12-month study and actual trial of a video distribution system for a primary school. It consisted of a main aerial distribution into a distribution junction box which also took video cassette recorders. The whole system was designed to distribute both in RF and video frequencies. Some ways of using the system have also been…

South Australia Education Dept., Adelaide.

140

Distributed snapshots: determining global states of distributed systems  

Microsoft Academic Search

This paper presents an algorithm by which a process in a distributed system determines a global state of the system during a computation. Many problems in distributed systems can be cast in terms of the problem of detecting global states. For instance, the global state detection algorithm helps to solve an important class of problems: stable property detection. A stable

Leslie Lamport

1985-01-01

141

Open System Architecture design for planet surface systems  

NASA Technical Reports Server (NTRS)

The Open System Architecture is an approach to meeting the needs for flexibility and evolution of the U.S. Space Exploration Initiative program of the manned exploration of the solar system and its permanent settlement. This paper investigates the issues that future activities of the planet exploration program must confront, defines the basic concepts that provide the basis for establishing an Open System Architecture, identifies the appropriate features of such an architecture, and discusses examples of Open System Architectures.

Petri, D. A.; Pieniazek, L. A.; Toups, L. D.

1992-01-01

142

Optimal reconfiguration of radial distribution systems to maximize loadability  

Microsoft Academic Search

This paper presents a new method for optimal reconfiguration of radial distribution systems (RDS). Optimal reconfiguration involves selection of the best set of branches to be opened, one each from each loop, such that the resulting RDS has the desired performance. Amongst the several performance criteria considered for optimal network reconfiguration, maximizing loadability is an important one. Owing to the

B. Venkatesh; Rakesh Ranjan; H. B. Gooi

2004-01-01

143

Video distribution system cost model  

NASA Technical Reports Server (NTRS)

A cost model that can be used to systematically identify the costs of procuring and operating satellite linked communications systems is described. The user defines a network configuration by specifying the location of each participating site, the interconnection requirements, and the transmission paths available for the uplink (studio to satellite), downlink (satellite to audience), and voice talkback (between audience and studio) segments of the network. The model uses this information to calculate the least expensive signal distribution path for each participating site. Cost estimates are broken downy by capital, installation, lease, operations and maintenance. The design of the model permits flexibility in specifying network and cost structure.

Gershkoff, I.; Haspert, J. K.; Morgenstern, B.

1980-01-01

144

On the controllability of distributed systems.  

PubMed

To "control" a system is to make it behave (hopefully) according to our "wishes," in a way compatible with safety and ethics, at the least possible cost. The systems considered here are distributed-i.e., governed (modeled) by partial differential equations (PDEs) of evolution. Our "wish" is to drive the system in a given time, by an adequate choice of the controls, from a given initial state to a final given state, which is the target. If this can be achieved (respectively, if we can reach any "neighborhood" of the target) the system, with the controls at our disposal, is exactly (respectively, approximately) controllable. A very general (and fuzzy) idea is that the more a system is "unstable" (chaotic, turbulent) the "simplest," or the "cheapest," it is to achieve exact or approximate controllability. When the PDEs are the Navier-Stokes equations, it leads to conjectures, which are presented and explained. Recent results, reported in this expository paper, essentially prove the conjectures in two space dimensions. In three space dimensions, a large number of new questions arise, some new results support (without proving) the conjectures, such as generic controllability and cases of decrease of cost of control when the instability increases. Short comments are made on models arising in climatology, thermoelasticity, non-Newtonian fluids, and molecular chemistry. The Introduction of the paper and the first part of all sections are not technical. Many open questions are mentioned in the text. PMID:11038539

Lions, J L

1997-05-13

145

Challenges of Using CSCL in Open Distributed Learning.  

ERIC Educational Resources Information Center

As a compulsory part of the study in Pedagogical Information Science at the University of Bergen and Stord/Haugesund College (Norway) during the spring term of 1999, students participated in a distributed group activity that provided experience on distributed collaboration and use of online groupware systems. The group collaboration process was…

Nilsen, Anders Grov; Instefjord, Elen J.

146

Open Loop Gust Alleviation System: Olga.  

National Technical Information Service (NTIS)

The application of a gust alleviation system on low wing loading aircraft, the open loop gust alleviation (OLGA) was examined. In the open loop principle the gust angle is calculated from the sensor signals and fed to the actuators which control the symme...

H. Boehret U. Nortmann M. Vonsarnowski W. Wagner H. Wuennenberg

1982-01-01

147

Building a generalized distributed system model  

NASA Technical Reports Server (NTRS)

A number of topics related to building a generalized distributed system model are discussed. The effects of distributed database modeling on evaluation of transaction rollbacks, the measurement of effects of distributed database models on transaction availability measures, and a performance analysis of static locking in replicated distributed database systems are covered.

Mukkamala, Ravi

1991-01-01

148

Developing an Open System for the Assessment of Technology in Education: The Data Gathering Agent.  

ERIC Educational Resources Information Center

Outlines design of an open computer system that relies on distributed computing for collection and storage of data from very large samples. Purpose of the system is to provide a base of reliable data for assessing impact of technology on delivery of educational materials. The system consists of an open instrument that generates student forms, an…

Oliva, Maurizio

1999-01-01

149

Planning of distribution systems with predominantly distributed generation  

Microsoft Academic Search

This paper presents a study of distribution system planning assuming a high penetration of distributed generation. Based on a power supply system with typical consumer structures, three scenarios with different levels of decentralization are defined. For these scenarios feasible networks are developed and discussed by a technical analysis. It is shown that the decentralized generation makes it possible to simplify

P. Asmuth; J. F. Verstege

2005-01-01

150

Optimal distribution substation locating in large distribution systems  

Microsoft Academic Search

The problem of distribution system planning is a large-scale, very complex and difficult to define problem. This paper presents the application of an efficient genetic algorithm (GA) for the optimal design of large distribution system, solving the optimal sizing and locating of substation using their corresponding fixed and variable cost as well as any operating and optimization constraints. As a

S. Najafi; A. Vahidnia; H. Hatami; S. Abachizadeh

2009-01-01

151

Voltage control availability of distributed generators in power distribution system  

Microsoft Academic Search

In spite of many profitable or advantageous natures of distributed generators (DGs), for power systems, such badly behaved natures of DGs as (1) unstable power output, (2) voltage problem, (3)harmonics, (4)reverse power flow, etc. also exist. Therefore, it has been always emphasized that the unfavorable effects should not exist when distributed generators are connected to the power system. However, in

K. Nara; S. Ishizu; Y. Mishima

2005-01-01

152

Optimal operation of distribution power system including distributed generator  

Microsoft Academic Search

A new model for distribution system reconfiguration (DSR) integrated with optimal power flow (OPF) and optimal capacitor switching (OCS) based on a hybrid approach is proposed in this paper. The objective is to minimize the generation cost of the whole distribution power system, and is subject to constraints such as capacity limit of branches, minimum and maximum power limits of

J. Shu; S. S. Quan; L. Z. Zhang

2010-01-01

153

The Planetary Data System Distributed Inventory System  

NASA Technical Reports Server (NTRS)

The advent of the World Wide Web (Web) and the ability to easily put data repositories on-line has resulted in a proliferation of digital libraries. The heterogeneity of the underlying systems, the autonomy of the individual sites, and distributed nature of the technology has made both interoperability across the sites and the search for resources within a site major research topics. This article will describe a system that addresses both issues using standard Web protocols and meta-data labels to implement an inventory of on-line resources across a group of sites. The success of this system is strongly dependent on the existence of and adherence to a standards architecture that guides the management of meta-data within participating sites.

Hughes, J. Steven; McMahon, Susan K.

1996-01-01

154

Security Criteria for Distributed Systems: Functional Requirements.  

National Technical Information Service (NTIS)

The focus of the security requirements presented in this report is on the design, implementation, and operation of trusted distributed operating systems. The view represented in this report is that any trusted distributed system consists of a set of Trust...

J. A. Cugini J. M. Boone R. W. Dobry T. Mayfield V. D. Gligor

1995-01-01

155

Open Source, Open Standards, and Health Care Information Systems  

PubMed Central

Recognition of the improvements in patient safety, quality of patient care, and efficiency that health care information systems have the potential to bring has led to significant investment. Globally the sale of health care information systems now represents a multibillion dollar industry. As policy makers, health care professionals, and patients, we have a responsibility to maximize the return on this investment. To this end we analyze alternative licensing and software development models, as well as the role of standards. We describe how licensing affects development. We argue for the superiority of open source licensing to promote safer, more effective health care information systems. We claim that open source licensing in health care information systems is essential to rational procurement strategy.

2011-01-01

156

Control of Distributed Uninterruptible Power Supply Systems  

Microsoft Academic Search

In the last years, the use of distributed uninterruptible power supply (UPS) systems has been growing into the market, becoming an alternative to large conventional UPS systems. In addition, with the increasing interest in renewable energy integration and distributed generation, distributed UPS systems can be a suitable solution for storage energy in micro grids. This paper depicts the most important

Josep M. Guerrero; Lijun Hang; Javier Uceda

2008-01-01

157

Utility distribution systems in Iceland. Special report  

Microsoft Academic Search

The study reports on new developments and special problems or solutions in water distribution systems, sewage collection systems, heat distribution and electric transmission systems in Iceland. Cold weather considerations are highlighted. For water and sewage transport, the use of ductile iron, concrete and plastic materials is reported. Utility lines are generally placed individually. Heat distribution with hot water from geothermal

Aamot; H. W. C

1976-01-01

158

Is data distribution necessary in OpenMP?  

Microsoft Academic Search

This paper investigates the performance implications of data placement in OpenMP programs running on modern ccNUMA multiprocessors. Data locality and minimization of the rate of remote memory accesses are critical for sustaining high performance on these systems. We show that due to the low remote-to-local memory access latency ratio of state-of-the-art ccNUMA architectures, reasonably balanced page placement schemes-such as round-robin

Dimitrios S. Nikolopoulos; Theodore S. Papatheodorou; Constantine D. Polychronopoulos; Jesus Labarta; Eduard Ayguadé

2000-01-01

159

A distributed program composition system  

NASA Technical Reports Server (NTRS)

A graphical technique for creating distributed computer programs is investigated and a prototype implementation is described which serves as a testbed for the concepts. The type of programs under examination is restricted to those comprising relatively heavyweight parts that intercommunicate by passing messages of typed objects. Such programs are often presented visually as a directed graph with computer program parts as the nodes and communication channels as the edges. This class of programs, called parts-based programs, is not well supported by existing computer systems; much manual work is required to describe the program to the system, establish the communication paths, accommodate the heterogeneity of data types, and to locate the parts of the program on the various systems involved. The work described solves most of these problems by providing an interface for describing parts-based programs in this class in a way that closely models the way programmers think about them: using sketches of diagraphs. Program parts, the computational modes of the larger program system are categorized in libraries and are accessed with browsers. The process of programming has the programmer draw the program graph interactively. Heterogeneity is automatically accommodated by the insertion of type translators where necessary between the parts. Many decisions are necessary in the creation of a comprehensive tool for interactive creation of programs in this class. Possibilities are explored and the issues behind such decisions are presented. An approach to program composition is described, not a carefully implemented programming environment. However, a prototype implementation is described that can demonstrate the ideas presented.

Brown, Robert L.

1989-01-01

160

Stability of distributed systems with feedback via Michailov's criterion.  

NASA Technical Reports Server (NTRS)

Development of a stability criterion of the Nyquist type from Michailov's criterion for a large class of distributed parameter systems, in particular, for a large class of transmission line systems with feedback. Following a generalization of Michailov's criterion, simplifying assumptions, usually valid in practice, are shown to yield a simplified test for determining whether 'encirclement-counting' constitutes a valid stability test. The results are reformulated for an open-loop analysis. Three examples show various aspects of the theoretical analysis.

Reis, G. C.

1972-01-01

161

Geometric phases in open tripod systems  

SciTech Connect

We first consider stimulated Raman adiabatic passages in a closed four-level tripod system. In this case, the adiabatic eigenstates of the system acquire real geometric phases. When the system is open and subject to decoherence they acquire complex geometric phases that we determine by a Monte Carlo wave function approach. We calculate the geometric phases and the state evolution in the closed as well as in the open system cases and describe the deviation between these in terms of the phases acquired. When the system is closed, the adiabatic evolution implements a Hadamard gate. The open system implements an imperfect gate and hence has a fidelity below unity. We express this fidelity in terms of the acquired geometric phases.

Moeller, Ditte; Madsen, Lars Bojer; Moelmer, Klaus [Lundbeck Foundation Theoretical Center for Quantum System Research, Department of Physics and Astronomy, University of Aarhus, DK-8000 (Denmark)

2008-02-15

162

Geometric phases in open tripod systems  

NASA Astrophysics Data System (ADS)

We first consider stimulated Raman adiabatic passages in a closed four-level tripod system. In this case, the adiabatic eigenstates of the system acquire real geometric phases. When the system is open and subject to decoherence they acquire complex geometric phases that we determine by a Monte Carlo wave function approach. We calculate the geometric phases and the state evolution in the closed as well as in the open system cases and describe the deviation between these in terms of the phases acquired. When the system is closed, the adiabatic evolution implements a Hadamard gate. The open system implements an imperfect gate and hence has a fidelity below unity. We express this fidelity in terms of the acquired geometric phases.

Møller, Ditte; Madsen, Lars Bojer; Mølmer, Klaus

2008-02-01

163

Plasma confinement studies in open systems  

NASA Astrophysics Data System (ADS)

Studies in open systems in the world are reviewed from viewpoints of the potential confinement and magnetohydrodynamic (MHD) stability. The tandem mirror GAMMA 10 has shown the potential confinement of a high-ion-temperature plasma from an analysis of the time evolution of end-loss ion current and end-loss ion energy distributions. The central cell density was increased by 50% by the potential confinement. In the HIEI tandem mirror H-mode-like phenomena were observed with an increase in density and diamagnetic signal in a limiter biasing experiment. Potential formation phenomena in plasmas are studied by 0741-3335/41/3A/024/img1-like Upgrade under different magnetic field configurations and plasma conditions. The fully axisymmetric tandem mirror AMBAL-M is under construction and its end mirror system has been assembled. Heating experiments of a plasma gun produced plasma by neutral beam injection and ICRF heating are in progress. The gas dynamic trap (GDT) experiment has successfully produced an MHD-stable high-temperature, high-density plasma. In GOL-3-II, a high-density plasma with several 100 eV temperature is created by powerful relativistic electron beam injection. Construction of HANBIT has been completed and experiments on plasma production and ICRF heating have begun.

Yatsu, Kiyoshi

1999-03-01

164

Distributed Power Balancing for the FREEDM System  

Microsoft Academic Search

The FREEDM microgrid is a test bed for a smart grid integrated with Distributed Grid Intelligence (DGI) to efficiently manage the distribution and storage of renewable energy. Within the FREEDM system, DGI applies distributed algorithms in a unique way to achieve economically feasible utilization and storage of alternative energy sources in a distributed fashion. The FREEDM microgrid consists of residential

Ravi Akella; Fanjun Meng; Derek Ditch; Bruce McMillin; Mariesa Crow

2010-01-01

165

VAXcluster: a closely-coupled distributed system  

Microsoft Academic Search

A VAXcluster is a highly available and extensible configuration of VAX computers that operate as a single system. To achieve performance in a multicomputer environment, a new communications architecture, communications hardware, and distributed software were jointly designed. The software is a distributed version of the VAX\\/VMS operating system that uses a distributed lock manager to synchronize access to shared resources.

Nancy P. Kronenberg; Henry M. Levy; William D. Strecker

1986-01-01

166

Low jitter RF distribution system  

DOEpatents

A timing signal distribution system includes an optical frequency stabilized laser signal amplitude modulated at an rf frequency. A transmitter box transmits a first portion of the laser signal and receive a modified optical signal, and outputs a second portion of the laser signal and a portion of the modified optical signal. A first optical fiber carries the first laser signal portion and the modified optical signal, and a second optical fiber carries the second portion of the laser signal and the returned modified optical signal. A receiver box receives the first laser signal portion, shifts the frequency of the first laser signal portion outputs the modified optical signal, and outputs an electrical signal on the basis of the laser signal. A detector at the end of the second optical fiber outputs a signal based on the modified optical signal. An optical delay sensing circuit outputs a data signal based on the detected modified optical signal. An rf phase detect and correct signal circuit outputs a signal corresponding to a phase stabilized rf signal based on the data signal and the frequency received from the receiver box.

Wilcox, Russell; Doolittle, Lawrence; Huang, Gang

2012-09-18

167

Generalized Model for Electric Distribution Systems.  

National Technical Information Service (NTIS)

A generalized mathematical model is constructed of single-phase induction machines employed within a three-phase distribution system. It is shown that this composite model retains single-phase distribution detail and describes the intrinsic characteristic...

H. J. Robinson T. W. Reddoch J. W. Klein

1981-01-01

168

Multicommodity Distribution System Design by Benders Decomposition.  

National Technical Information Service (NTIS)

A commonly occurring problem in distribution system design is the optimal location of intermediate distribution facilities between plants and customers. A multi-commodity capacitated single-period version of this problem is formulated as a mixed integer l...

A. Geoffrion G. W. Graves

1973-01-01

169

Livermore Distributed Storage System: Requirements and overview.  

National Technical Information Service (NTIS)

This paper outlines the requirements for a large-scale, distributed storage system, and describes how a system being developed at the Lawrence Livermore National Laboratory, called the LINCS Storage System (LSS), meets those requirements. The LSS provides...

C. Hogan L. Cassell J. Foglesong J. Kordas M. Nemanic

1990-01-01

170

Proton momentum distribution in water: an open path integral molecular dynamics study.  

PubMed

Recent neutron Compton scattering experiments have detected the proton momentum distribution in water. The theoretical calculation of this property can be carried out via "open" path integral expressions. In this work, present an extension of the staging path integral molecular dynamics method, which is then employed to calculate the proton momentum distributions of water in the solid, liquid, and supercritical phases. We utilize a flexible, single point charge empirical force field to model the system's interactions. The calculated momentum distributions depict both agreement and discrepancies with experiment. The differences may be explained by the deviation of the force field from the true interactions. These distributions provide an abundance of information about the environment and interactions surrounding the proton. PMID:17600422

Morrone, Joseph A; Srinivasan, Varadharajan; Sebastiani, Daniel; Car, Roberto

2007-06-21

171

Proton momentum distribution in water: an open path integral molecular dynamics study  

NASA Astrophysics Data System (ADS)

Recent neutron Compton scattering experiments have detected the proton momentum distribution in water. The theoretical calculation of this property can be carried out via ``open'' path integral expressions. In this work, present an extension of the staging path integral molecular dynamics method, which is then employed to calculate the proton momentum distributions of water in the solid, liquid, and supercritical phases. We utilize a flexible, single point charge empirical force field to model the system's interactions. The calculated momentum distributions depict both agreement and discrepancies with experiment. The differences may be explained by the deviation of the force field from the true interactions. These distributions provide an abundance of information about the environment and interactions surrounding the proton.

Morrone, Joseph A.; Srinivasan, Varadharajan; Sebastiani, Daniel; Car, Roberto

2007-06-01

172

Research in Distributed Real-Time Systems  

NASA Technical Reports Server (NTRS)

This document summarizes the progress we have made on our study of issues concerning the schedulability of real-time systems. Our study has produced several results in the scalability issues of distributed real-time systems. In particular, we have used our techniques to resolve schedulability issues in distributed systems with end-to-end requirements. During the next year (1997-98), we propose to extend the current work to address the modeling and workload characterization issues in distributed real-time systems. In particular, we propose to investigate the effect of different workload models and component models on the design and the subsequent performance of distributed real-time systems.

Mukkamala, R.

1997-01-01

173

Open systems architecture for integrated RF electronics  

Microsoft Academic Search

The Integrated Sensor System (ISS) program is defining an Open System Architecture (OSA) for Radio Frequency (RF) electronics, which represent the largest portion of an advanced aircraft's avionics flyaway cost. An integrated architecture is used to reduce costs in a number of ways, including time-sharing, centralization of resources, and reduction of the number of unique module types. The OSA approach

D. C. Hooks; B. A. Rich

1999-01-01

174

Open systems architecture for integrated RF electronics  

Microsoft Academic Search

The Integrated Sensor System (ISS) program is defining an Open System Architecture (OSA) for Radio Frequency (RF) electronics, which represent the largest portion of an advanced aircraft's avionics fly away cost. An integrated architecture is used to reduce costs in a number of ways, including time-sharing, centralization of resources, and reduction of the number of unique module types. The OSA

D. C. Hooks; B. A. Rich

1997-01-01

175

Open systems benefit energy control center  

Microsoft Academic Search

The ability to migrate applications among computers of different vendors and different sizes (from PCs to supercomputers), as operating needs change and grow, is described. Utility users want a basis for defining a strategy to update their energy management system (EMS) to be open and for continuous migration of their EMS to meet changing and expanding system operational needs. The

T. A. Green; A. Bose

1992-01-01

176

Distributed file systems: concepts and examples  

Microsoft Academic Search

The purpose of a distributed file system (DFS) is to allow users of physically distributed computers to share data and storage resources by using a common file system. A typical configuration for a DFS is a collection of workstations and mainframes connected by a local area network (LAN). A DFS is implemented as part of the operating system of each

Eliezer Levy; Abraham Silberschatz

1990-01-01

177

Heterogeneous distributed database systems for production use  

Microsoft Academic Search

It is increasingly important for organizations to achieve additional coordination of diverse computerized operations. To do so, it is necessary to have database systems that can operate over a distributed network and can encompass a heterogeneous mix of computers, operating systems, communications links, and local database management systems. This paper outlines approaches to various aspects of heterogeneous distributed data management

Gomer Thomas; Glenn R. Thompson; Chin-Wan Chung; Edward Barkmeyer; Fred Carter; Marjorie Templeton; Stephen Fox; Berl Hartman

1990-01-01

178

Load balancing in homogeneous broadcast distributed systems  

Microsoft Academic Search

Three different load balancing algorithms for distributed systems that consist of a number of identical processors and a CSMA communication system are presented in this paper. Some of the properties of a multi-resource system and the balancing process are demonstrated by an analytic model. Simulation is used as a mean for studying the interdependency between the parameters of the distributed

Miron Livnyand; Myron Melman

1982-01-01

179

Performance related issues in distributed database systems  

NASA Technical Reports Server (NTRS)

The key elements of research performed during the year long effort of this project are: Investigate the effects of heterogeneity in distributed real time systems; Study the requirements to TRAC towards building a heterogeneous database system; Study the effects of performance modeling on distributed database performance; and Experiment with an ORACLE based heterogeneous system.

Mukkamala, Ravi

1991-01-01

180

Building a generalized distributed system model  

NASA Technical Reports Server (NTRS)

A modeling tool for both analysis and design of distributed systems is discussed. Since many research institutions have access to networks of workstations, the researchers decided to build a tool running on top of the workstations to function as a prototype as well as a distributed simulator for a computing system. The effects of system modeling on performance prediction in distributed systems and the effect of static locking and deadlocks on the performance predictions of distributed transactions are also discussed. While the probability of deadlock is considerably small, its effects on performance could be significant.

Mukkamala, Ravi; Foudriat, E. C.

1991-01-01

181

NGSCB: A Trusted Open System  

Microsoft Academic Search

We describe Microsoft's Next Generation Secure Computing Base (NGSCB). The system provides high assurance computing in a manner consistent with the commercial requirements of mass market systems. This poses a number of challenges and we describe the system architecture we have used to overcome them. We pay particular attention to reducing the trusted computing base to a small and manageable

Marcus Peinado; Yuqun Chen; Paul England; John Manferdelli

2004-01-01

182

Empirical Tests of Zipf's Law Mechanism in Open Source Linux Distribution  

NASA Astrophysics Data System (ADS)

Zipf’s power law is a ubiquitous empirical regularity found in many systems, thought to result from proportional growth. Here, we establish empirically the usually assumed ingredients of stochastic growth models that have been previously conjectured to be at the origin of Zipf’s law. We use exceptionally detailed data on the evolution of open source software projects in Linux distributions, which offer a remarkable example of a growing complex self-organizing adaptive system, exhibiting Zipf’s law over four full decades.

Maillart, T.; Sornette, D.; Spaeth, S.; von Krogh, G.

2008-11-01

183

Open Hardware for CERN's accelerator control systems  

NASA Astrophysics Data System (ADS)

The accelerator control systems at CERN will be upgraded and many electronics modules such as analog and digital I/O, level converters and repeaters, serial links and timing modules are being redesigned. The new developments are based on the FPGA Mezzanine Card, PCI Express and VME64x standards while the Wishbone specification is used as a system on a chip bus. To attract partners, the projects are developed in an `Open' fashion. Within this Open Hardware project new ways of working with industry are being evaluated and it has been proven that industry can be involved at all stages, from design to production and support.

van der Bij, E.; Serrano, J.; Wlostowski, T.; Cattin, M.; Gousiou, E.; Alvarez Sanchez, P.; Boccardi, A.; Voumard, N.; Penacoba, G.

2012-01-01

184

State Electricity Regulatory Policy and Distributed Resources: Distribution System Cost Methodologies for Distributed Generation  

SciTech Connect

Designing and implementing credit-based pilot programs for distributed resources distribution is a low-cost, low-risk opportunity to find out how these resources can help defer or avoid costly electric power system (utility grid) distribution upgrades. This report describes implementation options for deaveraged distribution credits and distributed resource development zones. Developing workable programs implementing these policies can dramatically increase the deployment of distributed resources in ways that benefit distributed resource vendors, users, and distribution utilities. This report is one in the State Electricity Regulatory Policy and Distributed Resources series developed under contract to NREL (see Annual Technical Status Report of the Regulatory Assistance Project: September 2000-September 2001, NREL/SR-560-32733). Other titles in this series are: (1) Accommodating Distributed Resources in Wholesale Markets, NREL/SR-560-32497; (2) Distributed Resources and Electric System Re liability, NREL/SR-560-32498; (3) Distribution System Cost Methodologies for Distributed Generation, NREL/SR-560-32500; (4) Distribution System Cost Methodologies for Distributed Generation Appendices, NREL/SR-560-32501.

Shirley, W.; Cowart, R.; Sedano, R.; Weston, F.; Harrington, C.; Moskovitz, D.

2002-10-01

185

State Electricity Regulatory Policy and Distributed Resources: Distribution System Cost Methodologies for Distributed Generation; Appendices  

SciTech Connect

Designing and implementing credit-based pilot programs for distributed resources distribution is a low-cost, low-risk opportunity to find out how these resources can help defer or avoid costly electric power system (utility grid) distribution upgrades. This report describes implementation options for deaveraged distribution credits and distributed resource development zones. Developing workable programs implementing these policies can dramatically increase the deployment of distributed resources in ways that benefit distributed resource vendors, users, and distribution utilities. This report is one in the State Electricity Regulatory Policy and Distributed Resources series developed under contract to NREL (see Annual Technical Status Report of the Regulatory Assistance Project: September 2000-September 2001, NREL/SR-560-32733). Other titles in this series are: (1) Accommodating Distributed Resources in Wholesale Markets, NREL/SR-560-32497; (2) Distributed Resources and Electric System Re liability, NREL/SR-560-32498; (3) Distribution System Cost Methodologies for Distributed Generation, NREL/SR-560-32500; (4) Distribution System Cost Methodologies for Distributed Generation Appendices, NREL/SR-560-32501.

Shirley, W.; Cowart, R.; Sedano, R.; Weston, F.; Harrington, C.; Moskovitz, D.

2002-10-01

186

Programming languages for distributed computing systems  

Microsoft Academic Search

When distributed systems first appeared, they were programmed in traditional sequential languages, usually with the addition of a few library procedures for sending and receiving messages. As distributed applications became more commonplace and more sophisticated, this ad hoc approach became less satisfactory. Researchers all over the world began designing new programming languages specifically for implementing distributed applications. These languages and

Henri E. Bal; Jennifer G. Steiner; Andrew S. Tanenbaum

1989-01-01

187

Repeated interactions in open quantum systems  

NASA Astrophysics Data System (ADS)

Analyzing the dynamics of open quantum systems has a long history in mathematics and physics. Depending on the system at hand, basic physical phenomena that one would like to explain are, for example, convergence to equilibrium, the dynamics of quantum coherences (decoherence) and quantum correlations (entanglement), or the emergence of heat and particle fluxes in non-equilibrium situations. From the mathematical physics perspective, one of the main challenges is to derive the irreversible dynamics of the open system, starting from a unitary dynamics of the system and its environment. The repeated interactions systems considered in these notes are models of non-equilibrium quantum statistical mechanics. They are relevant in quantum optics, and more generally, serve as a relatively well treatable approximation of a more difficult quantum dynamics. In particular, the repeated interaction models allow to determine the large time (stationary) asymptotics of quantum systems out of equilibrium.

Bruneau, Laurent; Joye, Alain; Merkli, Marco

2014-07-01

188

Virtual PACS, open systems, and the National Information Infrastructure  

NASA Astrophysics Data System (ADS)

Teleradiology and telemedicine move images and related patient data from one medical treatment facility to another. Higher speed communication systems are rapidly being deployed as the national information infrastructure evolves. Demonstration projects have shown that higher performance networks permit an expanded scope of capabilities beyond simple image transmission to full PACS services at a distance. A virtual PACS that ties together several local PACS services is considdred. The interchange of informtion such that each of the local PACS knows about activity around the system is required. The database that tracks the acquisition of new medical exams may be distributed or may be centralized. A distributed database is proposed. Ramifications of the distributed virtual PACS include the possibility of restricting some services to be local and other services to be global. The virtual PACS will enable such things as a virtual radiology department with radiology specialists located at different places through the system. Sharing of specialists will increase their utilization, improve patient outcomes and reduce overall costs by reducing the need for every subspecialty at every location. Virtual PACS may be seen as a set of applications and services within the broader telecommunications framework of the national information infrastructure (NII). As such virtual PACS must be `open systems.' As defined here, an open system in the narrow sense requires a software platform that is widely supported and hardware independent. An open system is based on standards that are widely accepted and for which software is readily available from multiple sources. In the broader sense an open system is a set of services with standard interfaces distributed on a network and sharing common communication facilities. The NII depends on global consensus on appropriate standards. It is vital that medical image and information service components of the NII be carefully defined. The DICOM standard has been shown to be a key component of a global medical communication strategy and capable of forming the basis for constructing a virtual PACS. It is one of several complimentary standards that will be required for global open systems. To be useful in supporting radiology groups the NII should provide economical 2 to 10 megabyte per second services, considerably beyond the data rates available on the Internet today. Communication rates as low as 200 kilobytes per second (1.6 megabits per second) will introduce delays in service, but may be acceptable. Rates below about 64 kilobits per second destroy the utility of a radiology group serving a large area.

Wilson, Dennis L.; Prior, Fred W.; Glicksman, Robert A.

1995-05-01

189

An Architecture for Open Learning Management Systems  

Microsoft Academic Search

There exists an urgent demand on defining architectures for Learning Management Systems, so that high-level frameworks for understanding these systems can be discovered, and quality attributes like portability, interoperability, reusability and modifiability can be achieved. In this paper we propose a prototype architecture aimed to engineer Open Learning Management Systems, that professes state-of-the-art software engineering techniques such as layered structure

Simos Retalis; Manolis Skordalakis

2003-01-01

190

An Architecture for Open Learning Management Systems  

Microsoft Academic Search

There exists an urgent demand on defining architectures for Learning Management Systems, so that high-level frameworks for\\u000a understanding these systems can be discovered, and quality attributes like portability, interoperability, reusability and\\u000a modifiability can be achieved. In this paper we propose a prototype architecture aimed to engineer Open Learning Management\\u000a Systems, that professes state-of-the-art software engineering techniques such as layered structure

Symeon Retalis; Manolis Skordalakis

2001-01-01

191

Cardea: Dynamic Access Control in Distributed Systems.  

National Technical Information Service (NTIS)

Modern authorization systems span domains of administration, rely on many different authentication sources, and manage complex attributes as part of the authorization process. This . paper presents Cardea, a distributed system that facilitates dynamic acc...

R. Lepro

2004-01-01

192

Petri Net Controllers for Distributed Robotic Systems.  

National Technical Information Service (NTIS)

Petri nets are a well established modelling technique for analyzing parallel systems. When coupled with an event-driven operating system, Petri nets can provide an effective means for integrating and controlling the functions of distributed robotic applic...

D. R. Lefebvre G. N. Saridis

1992-01-01

193

Energy optimization of water distribution system.  

National Technical Information Service (NTIS)

In order to analyze pump operating scenarios for the system with the computer model, information on existing pumping equipment and the distribution system was collected. The information includes the following: component description and design criteria for...

1993-01-01

194

The Center for Networking and Distributed Systems  

NSDL National Science Digital Library

The Center for Networking and Distributed Systems and John Hopkins University "focuses on the interplay between theory and practice in distributed systems and networks." There are many resources on the centerâÂÂs Web site, including numerous research papers and publications. One of the papers listed will appear in the IEEE International Conference on Distributed Computing Systems in July 2002. Many of the centerâÂÂs research projects are described, which are investigating areas such as distributed clustering and metacomputing. There is also specialized software that can be downloaded free of charge under certain conditions.

195

Lighting system with heat distribution face plate  

DOEpatents

Lighting systems having a light source and a thermal management system are provided. The thermal management system includes synthetic jet devices, a heat sink and a heat distribution face plate. The synthetic jet devices are arranged in parallel to one and other and are configured to actively cool the lighting system. The heat distribution face plate is configured to radially transfer heat from the light source into the ambient air.

Arik, Mehmet; Weaver, Stanton Earl; Stecher, Thomas Elliot; Kuenzler, Glenn Howard; Wolfe, Jr., Charles Franklin; Li, Ri

2013-09-10

196

The Digital Distributed System Security Architecture  

Microsoft Academic Search

The Digital Distributed System Security Architecture is a comprehensive specification for security in a distributed system that employs state-of-the-art concepts to address the needs of both commercial and government environments. The architecture covers user and system authentication, mandatory and discretionary security, secure initialization and loading, and delegation in a general-purpose computing environment of heterogeneous systems where there are no central

Andy Goldstein; Butler Lampson; Charlie Kaufman; Morrie Gasser

1989-01-01

197

EDMAS: A locally distributed mail system  

Microsoft Academic Search

The Eden Project is a five-year effort to design, build and test operating system structures for local area networks. A specific goal is to allow users to obtain the advantages of both physical distribution and logical integration. Since Eden is physically distributed, its users can take advantage of personal workstations. Since Eden is logically integrated, system resources can be named

Guy T. Almes; Andrew P. Black; Carl Bunje; Douglas Wiebe

1984-01-01

198

Silver disinfection in water distribution systems  

NASA Astrophysics Data System (ADS)

Silver was evaluated as disinfectant to maintain water quality in water distribution system. It was used to inhibit growth of two opportunistic bacteria in planktonik form and in biofilm formation in Robbins devices with stainless steel and PVC surfaces. The results of this work show that silver is a potential secondary disinfectant to be used in water distribution systems.

Silvestry Rodriguez, Nadia

199

BIOFILMS IN DRINKING WATER DISTRIBUTION SYSTEMS  

EPA Science Inventory

Virtually anywhere a surface comes into contact with the water in a distribution system, one can find biofilms. Biofilms are formed in distribution system pipelines when microbial cells attach to pipe surfaces and multiply to form a film or slime layer on the pipe. Probably withi...

200

Hybrid solar lighting distribution systems and components  

DOEpatents

A hybrid solar lighting distribution system and components having at least one hybrid solar concentrator, at least one fiber receiver, at least one hybrid luminaire, and a light distribution system operably connected to each hybrid solar concentrator and each hybrid luminaire. A controller operates all components.

Muhs, Jeffrey D. (Lenoir City, TN) [Lenoir City, TN; Earl, Dennis D. (Knoxville, TN) [Knoxville, TN; Beshears, David L. (Knoxville, TN) [Knoxville, TN; Maxey, Lonnie C. (Powell, TN) [Powell, TN; Jordan, John K. (Oak Ridge, TN) [Oak Ridge, TN; Lind, Randall F. (Lenoir City, TN) [Lenoir City, TN

2011-07-05

201

A scalable distributed information management system  

Microsoft Academic Search

We present a Scalable Distributed Information Management System (SDIMS) that information about large-scale networked systems and that can serve as a basic building block for a broad range of large-scale distributed applications by providing detailed views of nearby information and summary views of global information. To serve as a basic building block, a SDIMS should have four properties: scalability to

Praveen Yalagandula; Michael Dahlin

2004-01-01

202

Pip: Detecting the Unexpected in Distributed Systems  

Microsoft Academic Search

Bugs in distributed systems are often hard to find. Many bugs reflect discrepancies between a system's be- havior and the programmer's assumptions about that be- havior. We present Pip1, an infrastructure for comparing actual behavior and expected behavior to expose struc- tural errors and performance problems in distributed sys- tems. Pip allows programmers to express, in a declara- tive language,

Patrick Reynolds; Charles Edwin Killian; Janet L. Wiener; Jeffrey C. Mogul; Mehul A. Shah; Amin Vahdat

2006-01-01

203

Cooperative Validation in Distributed Control Systems Design  

Microsoft Academic Search

The team of engineers designing and implementing distributed control system software must communicate within a multidisciplinary environment. One of the main problems is the interaction between hardware and software solutions. Software project presumptions may not be based only on minimum hardware requirements and on technology rules. Modern distributed control systems embrace all aspects of a complex and widespread object. Hence,

Dariusz Choinski; Mieczyslaw Metzger; Witold Nocon; Grzegorz Polaków

2007-01-01

204

Critical issues in distribution system surge protection  

Microsoft Academic Search

The past ten years have produced some dramatic advances in overvoltage protection for electricity distribution systems. Research into the nature of lightning-flash characteristics, especially the characteristics of distribution arrester discharge currents, now permit a greater understanding of the magnitudes of impulse voltages that impact the system and its connected equipment. Zinc oxide use has emerged during this same time period

W. J. Ros

1988-01-01

205

THE LIQUID AND GASEOUS FUEL DISTRIBUTION SYSTEM  

EPA Science Inventory

The report describes the national liquid and gaseous fuel distribution system. he study leading to the report was performed as part of an effort to better understand emissions of volatile organic compounds from the fuel distribution system. he primary, secondary, and tertiary seg...

206

Determining the impact of distributed generation on power systems. I. Radial distribution systems  

Microsoft Academic Search

Distributed generation (DG) has much potential to improve distribution system performance and it should be encouraged. However, distribution system designs and operating practices are normally based on radial power flows and this creates a special challenge to the successful introduction of distributed generation. This paper has described a few of the issues that must be considered to insure that DG

Philip P. Barker; Robert W. de Mello

2000-01-01

207

Extracting Overlay Invariants of Distributed Systems for Autonomic System Management  

Microsoft Academic Search

Many large-scale distributed systems have been built with great complexity to run Internet services. Due to the heterogeneity and dynamics of complex systems, it is very difficult to characterize their behavior precisely for system management. While we collect large amount of monitoring data from distributed systems as system observables, it is hard for us to interpret the data without constructing

Hanhuai Shan; Guofei Jiang; Kenji Yoshihira

2010-01-01

208

A rule-based expert system for distribution system service restoration  

Microsoft Academic Search

This paper presents the application of a rule-based expert system to the service restoration of distribution networks. The principal objective of the developed restoration plan is to minimize the number of switching operations without violating loading constraints in all elements of the network while retaining its open loop structure. The obtained results are encouraging

H. E. A. Talaat; S. El-Safty; M. M. Mansour; S. El-Debeiky

1999-01-01

209

Compositional Modeling of Reactive Systems Using Open Nets  

Microsoft Academic Search

In order to model the behaviour of open concurrent systems by means of Petri nets, we introduce open Petri nets, a generalization of the ordinary model where some places, designated as open, represent an interface of the system towards the environment. Besides generalizing the token game to reflect this extension, we define a truly concurrent semantics for open nets by

Paolo Baldan; Andrea Corradini; Hartmut Ehrig; Reiko Heckel

2001-01-01

210

Force-chain distributions in granular systems  

NASA Astrophysics Data System (ADS)

We study experimentally the distributions of force chains in granular materials, which are slightly different in sheared systems compared to isotropically compressed systems, especially at the tails, reflecting the shear-induced anisotropy of the contact force network. Ignoring this anisotropy allows us to establish a relationship between the mean force-chain length Lm and the average contact number Z of particles for both systems, independent of the system size. We also demonstrate that force-chain distributions are not related to the exponential-like distributions of stresses.

Zhang, Ling; Wang, Yujie; Zhang, Jie

2014-01-01

211

Differences Between Distributed and Parallel Systems  

SciTech Connect

Distributed systems have been studied for twenty years and are now coming into wider use as fast networks and powerful workstations become more readily available. In many respects a massively parallel computer resembles a network of workstations and it is tempting to port a distributed operating system to such a machine. However, there are significant differences between these two environments and a parallel operating system is needed to get the best performance out of a massively parallel system. This report characterizes the differences between distributed systems, networks of workstations, and massively parallel systems and analyzes the impact of these differences on operating system design. In the second part of the report, we introduce Puma, an operating system specifically developed for massively parallel systems. We describe Puma portals, the basic building blocks for message passing paradigms implemented on top of Puma, and show how the differences observed in the first part of the report have influenced the design and implementation of Puma.

Brightwell, R.; Maccabe, A.B.; Rissen, R.

1998-10-01

212

Transitionless quantum driving in open quantum systems  

NASA Astrophysics Data System (ADS)

We extend the concept of superadiabatic dynamics, or transitionless quantum driving, to quantum open systems whose evolution is governed by a master equation in the Lindblad form. We provide the general framework needed to determine the control strategy required to achieve superadiabaticity. We apply our formalism to two examples consisting of a two-level system coupled to environments with time-dependent bath operators.

Vacanti, G.; Fazio, R.; Montangero, S.; Palma, G. M.; Paternostro, M.; Vedral, V.

2014-05-01

213

Heat pump thermal distribution systems  

Microsoft Academic Search

A large volume of information on conceptual heat pump systems, component costs and expected operating costs were generated for a wide variety of heat pump systems during this study. Detailed results of this work, too lengthy to be reported in a single volume, have been included in these appendices, which are designated as Volume II of this study. Schematics of

P. Sarkisian; B. Cohen; A. Popelka

1990-01-01

214

Open architecture test system: system architecture and design  

Microsoft Academic Search

The open architecture test system provides a method and framework under which software and instruments of different vendors can be developed and integrated into an ATE. In This work, we describe the overall architecture and design of the system. First we describe the architecture and the control mechanism for the overall system and for individual test-sites. Data and command communication

Rochit Rajsuman; M. Noriyuki

2004-01-01

215

Open Architecture Test System: System Architecture and Design  

Microsoft Academic Search

The Open Architecture Test System provides a method and framework under which software and instruments of different vendors can be developed and integrated into an ATE. In this paper, we describe the overall architecture and design of the system. First we describe the architecture and the control mechanism for the overall system and for individual test-sites. Data and command communication

Rochit Rajsuman; Masuda Noriyuki

2004-01-01

216

Human tracking using distributed vision systems  

Microsoft Academic Search

We present a wide area human tracking method using distributed computer vision systems. Each vision system consists of a camera and an image processor and they are all connected through a computer network. In this paper, we propose a method for human tracking and for coordination of all the vision systems. The human tracking method works on each vision system

Atsushi NAKAZAWA; Hirokazu KATO; Seiji INOKUCHI

1998-01-01

217

Hybrid control of the distributed refrigeration system  

Microsoft Academic Search

The supermarket refrigeration system typically has a distributed control structure, which neglects interactions between its subsystems. These interactions from time to time lead to a synchronization operation of the display-cases which causes an inferior control performance and increased energy consumption. The paper focuses on synchronization dynamics of the refrigeration system modeled as a piecewise-affine switched system. System behaviors are analyzed

Liang Chen; Rafael Wisniewski

2010-01-01

218

Distributed Secure Systems: Then and Now  

Microsoft Academic Search

The early 1980s saw the development of some rather sophisticated distributed systems. These were not merely networked file systems: rather, using remote procedure calls, hierarchical naming, and what would now be called middleware, they allowed a collection of systems to operate as a coherent whole. One such system in particular was developed at Newcastle that allowed pre-existing applications and (Unix)

Brian Randell

2007-01-01

219

Analysis of Short Circuits for Distribution Systems  

Microsoft Academic Search

This paper presents a discussion and analysis of short circuits for low-voltage distribution systems. Many distribution systems are supplied from transformers connected in delta on the low-voltage side with the mid-tap of one secondary winding, or with one corner of the delta, connected to ground. As a result, short circuits on these systems often involve failure to ground, and an

Charles F. Dalziel

1942-01-01

220

Measuring Advances in HVAC Distribution System Design  

SciTech Connect

Substantial commercial building energy savings have been achieved by improving the performance of the HV AC distribution system. The energy savings result from distribution system design improvements, advanced control capabilities, and use of variable-speed motors. Yet, much of the commercial building stock remains equipped with inefficient systems. Contributing to this is the absence of a definition for distribution system efficiency as well as the analysis methods for quantifying performance. This research investigates the application of performance indices to assess design advancements in commercial building thermal distribution systems. The index definitions are based on a first and second law of thermodynamics analysis of the system. The second law or availability analysis enables the determination of the true efficiency of the system. Availability analysis is a convenient way to make system efficiency comparisons since performance is evaluated relative to an ideal process. A TRNSYS simulation model is developed to analyze the performance of two distribution system types, a constant air volume system and a variable air volume system, that serve one floor of a large office building. Performance indices are calculated using the simulation results to compare the performance of the two systems types in several locations. Changes in index values are compared to changes in plant energy, costs, and carbon emissions to explore the ability of the indices to estimate these quantities.

Franconi, E.

1998-05-01

221

Resource Management for Distributed Parallel Systems  

NASA Technical Reports Server (NTRS)

Multiprocessor systems should exist in the the larger context of distributed systems, allowing multiprocessor resources to be shared by those that need them. Unfortunately, typical multiprocessor resource management techniques do not scale to large networks. The Prospero Resource Manager (PRM) is a scalable resource allocation system that supports the allocation of processing resources in large networks and multiprocessor systems. To manage resources in such distributed parallel systems, PRM employs three types of managers: system managers, job managers, and node managers. There exist multiple independent instances of each type of manager, reducing bottlenecks. The complexity of each manager is further reduced because each is designed to utilize information at an appropriate level of abstraction.

Neuman, B. Clifford; Rao, Santosh

1993-01-01

222

Open Source Real Time Operating Systems Overview  

SciTech Connect

Modern control systems applications are often built on top of a real time operating system (RTOS) which provides the necessary hardware abstraction as well as scheduling, networking and other services. Several open source RTOS solutions are publicly available, which is very attractive, both from an economic (no licensing fees) as well as from a technical (control over the source code) point of view. This contribution gives an overview of the RTLinux and RTEMS systems (architecture, development environment, API etc.). Both systems feature most popular CPUs, several APIs (including Posix), networking, portability and optional commercial support. Some performance figures are presented, focusing on interrupt latency and context switching delay.

Straumann, Till

2001-12-11

223

Quantum mechanics of open systems  

NASA Astrophysics Data System (ADS)

In quantum mechanics, there is a set of problems where the system of interest interacts with another system, usually called "environment". This interaction leads to the exchange of energy and information and makes the dynamics of the system of interest essentially non-unitary. Such problems often appeared in condensed matter physics and attracted much attention after recent advances in nanotechnology. As broadly posed as they are, these problems require a variety of different approaches. This thesis is an attempt to examine several of these approaches in applications to different condensed matter problems. The first problem concerns the so-called "Master equation" approach which is very popular in quantum optics. I show that analytic properties of environmental correlators lead to strong restrictions on the applicability of the approach to the strong-coupling regime of interest in condensed matter physics. In the second problem, I use path integrals to treat the localization of particles on attractive short-range potentials when the environment produces an effective viscous friction force. I find that friction changes drastically the localization properties and leads to much stronger localization in comparison to the non-dissipative case. This has implications for the motion of heavy particles in fermionic liquids and, as will be argued below, is also relevant to the problem of high-temperature superconductivity. Finally, the third problem deals with the interplay of geometric phases and energy dissipation which occurs in the motion of vortices in superconductors. It is shown that this interplay leads to interesting predictions for vortex tunneling in high-temperature superconductors which have been partially confirmed by experiments.

Melikidze, Akakii

224

An Open-Control Concept for a Holonic Multiagent System  

NASA Astrophysics Data System (ADS)

MAS are particularly adapted to deal with distributed and dynamic environment. The management of business workflow, or data flow, flexible manufacturing systems is typically a good application field for them. This kind of application requires centralization of the data control and flexibility to face with changes on the network. In the context of FMS, where products and resources entities can be seen as active, this paper presents the open-control concept and gives an example of its instantiation with holonic scheme. The open-control concept proposed in this paper exhibits the classic explicit control, as well as an innovative type of control called implicit control that allows system entities to be influenced via an Optimization Mechanism (OM). We illustrate our proposition by an implementation on a flexible assembly cell in our university.

Adam, Emmanuel; Berger, Thierry; Sallez, Yves; Trentesaux, Damien

225

Integrating photovoltaics into utility distribution systems  

SciTech Connect

Electric utility distribution system impacts associated with the integration of distributed photovoltaic (PV) energy sources vary from site to site and utility to utility. The objective of this paper is to examine several utility- and site-specific conditions which may affect economic viability of distributed PV applications to utility systems. Assessment methodology compatible with technical and economic assessment techniques employed by utility engineers and planners is employed to determine PV benefits for seven different utility systems. The seven case studies are performed using utility system characteristics and assumptions obtained from appropriate utility personnel. The resulting site-specific distributed PV benefits increase nonsite-specific generation system benefits available to central station PV plants as much as 46%, for one utility located in the Southwest.

Zaininger, H.W. [Zaininger Engineering Co., Inc., San Jose, CA (United States); Barnes, P.R. [Oak Ridge National Lab., TN (United States)

1995-03-01

226

Development of an Integrated Distribution Management System  

SciTech Connect

This final report details the components, functionality, costs, schedule and benefits of developing an Integrated Distribution Management System (IDMS) for power distribution system operation. The Distribution Automation (DA) and Supervisory Control and Data Acquisition (SCADA) systems used by electric power companies to manage the distribution of electric power to retail energy consumers are vital components of the Nation’s critical infrastructure. Providing electricity is an essential public service and a disruption in that service, if not quickly restored, could threaten the public safety and the Nation’s economic security. Our Nation’s economic prosperity and quality of life have long depended on the essential services that utilities provide; therefore, it is necessary to ensure that electric utilities are able to conduct their operations safely and efficiently. A fully integrated technology of applications is needed to link various remote sensing, communications and control devices with other information tools that help guide Power Distribution Operations personnel. A fully implemented IDMS will provide this, a seamlessly integrated set of applications to raise electric system operating intelligence. IDMS will enhance DA and SCADA through integration of applications such as Geographic Information Systems, Outage Management Systems, Switching Management and Analysis, Operator Training Simulator, and other Advanced Applications, including unbalanced load flow and fault isolation/service restoration. These apps are capable of utilizing and obtaining information from appropriately installed DER, and by integrating disparate systems, the Distribution Operators will benefit from advanced capabilities when analyzing, controlling and operating the electric system.

Schatz, Joe E.

2010-10-20

227

Grid Services for Distributed System Integration  

Microsoft Academic Search

abstractions and concepts that let applications access and share resources and services across dis-tributed, wide area networks, while providing com-mon security semantics, distributed resource management performance, coordinated fail-over, problem determination services, or other QoS met-rics that are of importance in a particular context. For some time, such problems have been of cen-tral concern to developers of distributed systems for large-scale

Ian T. Foster; Carl Kesselman; Jeffrey M. Nick; Steven Tuecke

2002-01-01

228

Man-systems distributed system for Space Station Freedom  

NASA Technical Reports Server (NTRS)

Viewgraphs on man-systems distributed system for Space Station Freedom are presented. Topics addressed include: description of man-systems (definition, requirements, scope, subsystems, and topologies); implementation (approach, tools); man-systems interfaces (system to element and system to system); prime/supporting development relationship; selected accomplishments; and technical challenges.

Lewis, J. L.

1990-01-01

229

Air Mobile Utility Distribution Systems.  

National Technical Information Service (NTIS)

Phase I involved: (1) a feasibility study of various plastic piping and insulation systems, (2) a state of the art survey to select candidate materials for testing and evaluation, (3) selection and development of a suitable testing program. Phase II consi...

M. A. White F. W. Spillers R. D. Duke

1975-01-01

230

Supervisory Control and Diagnostics System Distributed Operating System.  

National Technical Information Service (NTIS)

This paper contains a description of the Supervisory Control and Diagnostics System (SCDS) Distributed Operating System. The SCDS consists of nine 32-bit minicomputers with shared memory. The system's main purpose is to control a large Mirror Fusion Test ...

P. R. McGoldrick

1979-01-01

231

Shuttle: Reaction control system. Cryogenic liquid distribution system: Study  

NASA Technical Reports Server (NTRS)

A cryogenic liquid distribution system suitable for the reaction control system on space shuttles is described. The system thermodynamics, operation, performance and weight analysis are discussed along with the design, maintenance and integration concepts.

Akkerman, J. W.

1972-01-01

232

Distributed Administrative Management Information System (DAMIS).  

ERIC Educational Resources Information Center

Columbia University's major program to distribute its central administrative data processing to its various schools and departments is described. The Distributed Administrative Management Information System (DAMIS) will link every department and school within the university via micrcomputers, terminals, and/or minicomputers to the central…

Juckiewicz, Robert; Kroculick, Joseph

233

Distributing Executive Information Systems through Networks.  

ERIC Educational Resources Information Center

Many colleges and universities will soon adopt distributed systems for executive information and decision support. Distribution of shared information through computer networks will improve decision-making processes dramatically on campuses. Critical success factors include administrative support, favorable organizational climate, ease of use,…

Penrod, James I.; And Others

1993-01-01

234

BIOFILM IN DRINKING WATER DISTRIBUTION SYSTEMS  

EPA Science Inventory

Throughout the world there are millions of miles of water distribution pipe lines which provide potable water for use by individuals and industry. Some of these water distribution systems have been in service well over one hundred years. Treated water moving through a distributio...

235

Distributed Systems, OSF DCE, and Beyond  

Microsoft Academic Search

This introduction paper presents basic foundations of distributed systems and applications and then shows how OSF DCE addresses the requirements imposed by distributed environments. The DCE architecture is illustrated, the basic functionality of the DCE components is explained, and the DCE RPC as the major base for client\\/server applications is presented in closer detail.

Martin Bever; Kurt Geihs; Lutz Heuser; Max Mühlhäuser; Alexander Schill

1993-01-01

236

Distributed control system for turbine engines  

Microsoft Academic Search

A distributed control system (DCS) for a turbine engine has been demonstrated and tested, consisting of prototype electronic interface units (EIUs) connected to data and power busses. In the DCS, a central control computer communicated with smart sensors and smart actuators via a 2.5 megabit\\/sec digital data bus, using the Fieldbus protocol. Power was distributed to the smart devices as

P. L. Shaffer

1999-01-01

237

Coordinated action in reverse distribution systems  

Microsoft Academic Search

Purpose – The purpose of this paper is to address the prerequisites for achieving coordinated action in reverse distribution systems. It is an underlying assumption in distribution, logistics and supply chain management that a higher level of coordination between the actors is superior to a lower, and a higher levels of coordination will in turn lead to increased performance. Coordination

Bente M. Flygansvær; Lars-Erik Gadde; Sven A. Haugland

2008-01-01

238

A PILOT ENVIRONMENTAL DATA GRID DISTRIBUTION SYSTEM  

EPA Science Inventory

The primary objectives of this study are to implement, operate, and evaluate a workable, distributed data access, format neutral "data-on-demand" prototype, leveraging leading-edge technologies assembled in a unique operational prototype system and distributed over the U.S. EPA's...

239

Intelligent Supervisory Controller for Gas Distribution System  

Microsoft Academic Search

This paper describes the application of artificial intelligence techniques in the supervisory controller of a gas distribution network. The main idea was to use symbolic models of the distribution network in the knowledge-based system components. The symbolic models represented various quantitative and qualitative features of the process which made it possible to support the monitoring, diagnostic and intervention planning procedures

G. Karsai; W. Blokland; C. Biegl; J. Sztipanovits; K. Kawamura; N. Miyasaka; M. Inui

1987-01-01

240

Parallel and Distributed System Simulation  

NASA Technical Reports Server (NTRS)

This exploratory study initiated our research into the software infrastructure necessary to support the modeling and simulation techniques that are most appropriate for the Information Power Grid. Such computational power grids will use high-performance networking to connect hardware, software, instruments, databases, and people into a seamless web that supports a new generation of computation-rich problem solving environments for scientists and engineers. In this context we looked at evaluating the NetSolve software environment for network computing that leverages the potential of such systems while addressing their complexities. NetSolve's main purpose is to enable the creation of complex applications that harness the immense power of the grid, yet are simple to use and easy to deploy. NetSolve uses a modular, client-agent-server architecture to create a system that is very easy to use. Moreover, it is designed to be highly composable in that it readily permits new resources to be added by anyone willing to do so. In these respects NetSolve is to the Grid what the World Wide Web is to the Internet. But like the Web, the design that makes these wonderful features possible can also impose significant limitations on the performance and robustness of a NetSolve system. This project explored the design innovations that push the performance and robustness of the NetSolve paradigm as far as possible without sacrificing the Web-like ease of use and composability that make it so powerful.

Dongarra, Jack

1998-01-01

241

Distributed system for electrical power quality improvement  

Microsoft Academic Search

On the basis of the current trends for solving complex technical problems, a new concept of power quality improvement is proposed. It consists in creating a distributed system for supply conditions improvement in a given islanding power system, in e.g. geographical terms (with determined points of delivery), or as an internal installation system of an industrial consumer.

KLEMPKA Ryszard

2008-01-01

242

Communication synthesis for distributed embedded systems  

Microsoft Academic Search

Designers of distributed embedded systems face many challenges in determining the appropriate tradeoffs to make when defining a system architecture or retargeting an existing design. Communica- tion synthesis, the automatic generation of the necessary software and hardware needed for system components to exchange data, is required to more effectively explore the design space and automate what are very error-prone tasks.

Ross B. Ortega; Gaetano Borriello

1998-01-01

243

DCBITS: Distributed Case Base Intelligent Tutoring System  

Microsoft Academic Search

Online learning with Intelligent Tutoring System (ITS) is becoming very popular where the system models the student's learning behavior and presents to the student the learning material (content, questions-answers, assignments) accordingly. In today's distributed computing environment, the tutoring system can take advantage of networking to utilize the model for a student for students from other similar groups. In the present

O. P. Rishi; Rekha Govil

2008-01-01

244

Computer aided engineering of distributed control systems  

Microsoft Academic Search

For a large plant, engineering the distributed control system in the shortest possible time is extremely important. Increasingly, it is being realised that cutting down the project cycle time is the key to success in the international market place. Most companies have therefore developed computer aided tools for control systems engineering rule design. These systems are proprietary in nature. The

P. Purkayashta; Sonika Sood; K. Padmanabhan

1995-01-01

245

Network design consideration for distributed control systems  

Microsoft Academic Search

This paper discusses the impact of network architecture on control performance in a class of distributed control systems called networked control systems (NCSs) and provides design considerations related to control quality of performance as well as network quality of service. The integrated network-control system changes the characteristics of time delays between application devices. This study first identifies several key components

Feng-Li Lian; James Moyne; Dawn Tilbury

2002-01-01

246

Computer Systems for Distributed and Distance Learning.  

ERIC Educational Resources Information Center

Discussion of network-based learning focuses on a survey of computer systems for distributed and distance learning. Both Web-based systems and non-Web-based systems are reviewed in order to highlight some of the major trends of past projects and to suggest ways in which progress may be made in the future. (Contains 92 references.) (Author/LRW)

Anderson, M.; Jackson, David

2000-01-01

247

Differences Between Distributed and Parallel Systems.  

National Technical Information Service (NTIS)

Distributed systems have been studied for twenty years and are now coming into wider use as fast networks and powerful workstations become more readily available. In many respects a massively parallel computer resembles a network of workstations and it is...

R. Brightwell A. B. Maccabe R. Rissen

1998-01-01

248

Tactical Water Distribution System (TWDS) Conduit Test.  

National Technical Information Service (NTIS)

This report summarizes testing conducted by this command for potential conduits/couplings used in the Tactical Water Distribution System. Three conduit/coupling candidates were evaluated on the basis of their hydraulic properties: rigid pipe with groove a...

G. W. Rutherford

1982-01-01

249

Name Server Design for Distributed Systems.  

National Technical Information Service (NTIS)

Name servers are programs that provide a uniform method of naming resources and retrieving information about those resources in the context of a distributed system. This paper examines the main issues in name server design and considers some contemporary ...

J. Postel P. Kirton P. Mockapetris

1984-01-01

250

General Distributed Control System for Fusion Experiments.  

National Technical Information Service (NTIS)

A general control system using distributed LSI-11 microprocessors is being developed. Common software residues in each LSI-11 and is tailored to an application by control specifications downloaded from a host computer. The microprocessors, their control i...

P. L. Klingner S. J. Levings R. W. Wilkins

1986-01-01

251

Adaptive Distribution System Protection: Final Report.  

National Technical Information Service (NTIS)

This report presents concepts, functions, and organizations of adaptive distribution system protection (ADSP) schemes. ADSP constantly monitors real time data, update relay characteristics and upper and lower bounds of control functions when required, and...

K. R. Shan

1987-01-01

252

Energy optimization of water distribution systems.  

National Technical Information Service (NTIS)

Energy costs associated with pumping treated water into the distribution system and boosting water pressures where necessary is one of the largest expenditures in the operating budget of a municipality. Due to the size and complexity of Detroit's water tr...

1994-01-01

253

Distributed Architectures for Event-Based Systems  

Microsoft Academic Search

\\u000a Event-driven distributed systems have two important characteristics, which differentiate them from other system types: the\\u000a existence of several software or hardware components that run simultaneously on different inter-networked nodes, and the use\\u000a of events as the main vehicle to organize component intercommunication. Clearly, both attributes influence event-driven distributed\\u000a architectures, which are discussed in this chapter. We start with presenting the

Valentin Cristea; Florin Pop; Ciprian Dobre; Alexandru Costan

254

Examination and characterization of distribution system biofilms.  

PubMed Central

Investigations concerning the role of distribution system biofilms on water quality were conducted at a drinking water utility in New Jersey. The utility experienced long-term bacteriological problems in the distribution system, while treatment plant effluents were uniformly negative for coliform bacteria. Results of a monitoring program showed increased coliform levels as the water moved from the treatment plant through the distribution system. Increased coliform densities could not be accounted for by growth of the cells in the water column alone. Identification of coliform bacteria showed that species diversity increased as water flowed through the study area. All materials in the distribution system had high densities of heterotrophic plate count bacteria, while high levels of coliforms were detected only in iron tubercles. Coliform bacteria with the same biochemical profile were found both in distribution system biofilms and in the water column. Assimilable organic carbon determinations showed that carbon levels declined as water flowed through the study area. Maintenance of a 1.0-mg/liter free chlorine residual was insufficient to control coliform occurrences. Flushing and pigging the study area was not an effective control for coliform occurrences in that section. Because coliform bacteria growing in distribution system biofilms may mask the presence of indicator organisms resulting from a true breakdown of treatment barriers, the report recommends that efforts continue to find methods to control growth of coliform bacteria in pipeline biofilms. Images

LeChevallier, M W; Babcock, T M; Lee, R G

1987-01-01

255

Ultra stable frequency distribution system  

NASA Technical Reports Server (NTRS)

A system is presented for synchronizing a signal at a remotely located slave station with the phase and frequency of a signal generated at a master station. The signal transmitted at the master station and received by the slave station provides compensation for the phase shift caused by the transmission path delays between the master and slave station. The slave station transmits a signal to the master station at a frequency that is different from the frequency of the signal being transmitted by the master station. The signal transmitted by the slave station is received by the master station while the master station transmitter is off. The signal transmitted by the master station is received by the slave station while the slave station transmitter is off.

Sydnor, R. L.; Macconnell, J. W. (inventors)

1977-01-01

256

DIstributed VIRtual System (DIVIRS) Project  

NASA Technical Reports Server (NTRS)

The development of Prospero moved from the University of Washington to ISI and several new versions of the software were released from ISI during the contract period. Changes in the first release from ISI included bug fixes and extensions to support the needs of specific users. Among these changes was a new option to directory queries that allows attributes to be returned for all files in a directory together with the directory listing. This change greatly improves the performance of their server and reduces the number of packets sent across their trans-pacific connection to the rest of the internet. Several new access method were added to the Prospero file method. The Prospero Data Access Protocol was designed, to support secure retrieval of data from systems running Prospero.

Schorr, Herbert; Neuman, B. Clifford; Gaines, Stockton R.; Mizell, David

1996-01-01

257

State and dynamical parameter estimation for open quantum systems  

NASA Astrophysics Data System (ADS)

Following evolution of an open quantum system one requires full knowledge of its dynamics. In this paper we consider open quantum systems for which the Hamiltonian is ``uncertain.'' In particular, we treat in detail a simple system similar to that considered by Mabuchi [Quant. Semiclass. Opt. 8, 1103 (1996)]: a radiatively damped atom driven by an unknown Rabi frequency ? (as would occur for an atom at an unknown point in a standing light wave). By measuring the environment of the system, knowledge about the system state, and about the uncertain dynamical parameter, can be acquired. We find that these two sorts of knowledge acquisition (quantified by the posterior distribution for ?, and the conditional purity of the system, respectively) are quite distinct processes, which are not strongly correlated. Also, the quality and quantity of knowledge gain depend strongly on the type of monitoring scheme. We compare five different detection schemes (direct, adaptive, homodyne of the x quadrature, homodyne of the y quadrature, and heterodyne) using four different measures of the knowledge gain (Shannon information about ?, variance in ?, long-time system purity, and short-time system purity).

Gambetta, Jay; Wiseman, H. M.

2001-10-01

258

An Open System for Intravascular Ultrasound Imaging  

PubMed Central

Visualization of the blood vessels can provide valuable morphological information for diagnosis and therapy strategies for cardiovascular disease. Intravascular ultrasound (IVUS) is able to delineate internal structures of vessel wall with fine spatial resolution. However, the developed IVUS is insufficient to identify the fibrous cap thickness and tissue composition of atherosclerotic lesions. Novel imaging strategies have been proposed, such as increasing the center frequency of ultrasound or using a modulated excitation technique to improve the accuracy of diagnosis. Dual-mode tomography combining IVUS with optical tomography has also been developed to determine tissue morphology and characteristics. The implementation of these new imaging methods requires an open system that allows users to customize the system for various studies. This paper presents the development of an IVUS system that has open structures to support various imaging strategies. The system design is based on electronic components and printed circuit board, and provides reconfigurable hardware implementation, programmable image processing algorithms, flexible imaging control, and raw RF data acquisition. In addition, the proposed IVUS system utilized a miniaturized ultrasound transducer constructed using PMN-PT single crystal for better piezoelectric constant and electromechanical coupling coefficient than traditional lead zirconate titanate (PZT) ceramics. Testing results showed that the IVUS system could offer a minimum detectable signal of 25 ?V, allowing a 51 dB dynamic range at 47 dB gain, with a frequency range from 20 to 80 MHz. Finally, phantom imaging, in vitro IVUS vessel imaging, and multimodality imaging with photoacoustics were conducted to demonstrate the performance of the open system.

Qiu, Weibao; Chen, Yan; Li, Xiang; Yu, Yanyan; Cheng, Wang Fai; Tsang, Fu Keung; Zhou, Qifa; Shung, K. Kirk; Dai, Jiyan; Sun, Lei

2013-01-01

259

Lightning protection of distribution systems. Final report  

SciTech Connect

Analyses are presented of experimental data obtained in the Tampa Bay area during 1978 and 1979 concerning the physical and phenomenological properties of lightning and the interaction of that lightning with the local distribution power systems. Specific results are given regarding: (1) the physical and phenomenology properties of lightning in the Tampa Bay area and its relation to lightning elsewhere; (2) measurement and theory concerning lightning-induced voltages on distribution lines; (3) distribution system operation in the presence of lightning and analytical modeling and prediction of that operation.

Uman, M.A.

1985-02-01

260

Studying distribution system reliability against lightning  

SciTech Connect

In this article, the authors present a general overview of the use of computers in different areas of a research project intended to study the adequate protection of distribution systems against lightning. First, the effects of lightning on electric power distribution will be presented; then, a discussion on the modeling of lightning phenomena and other areas that are needed to perform analytical studies to predict distribution system reliability against lightning will be given. Subsequently, a brief description will be given of field measurements of ground flash density and lightning location. Finally, we will enumerate areas that have been identified as requiring further research.

Romualdo, C.; Brito, F.; Perez, H.; De la Rosa, F.; Sarmiento, H.G.

1989-01-01

261

Heterogeneous distributed query processing: The DAVID system  

NASA Technical Reports Server (NTRS)

The objective of the Distributed Access View Integrated Database (DAVID) project is the development of an easy to use computer system with which NASA scientists, engineers and administrators can uniformly access distributed heterogeneous databases. Basically, DAVID will be a database management system that sits alongside already existing database and file management systems. Its function is to enable users to access the data in other languages and file systems without having to learn the data manipulation languages. Given here is an outline of a talk on the DAVID project and several charts.

Jacobs, Barry E.

1985-01-01

262

Test procedures and protocols: Their relevance to the figure of merit for thermal distribution systems. Volume 1: Informal report.  

National Technical Information Service (NTIS)

A conceptual framework is developed that categorizes measurement protocols for forced-air thermal distribution systems in small buildings. This framework is based on the distinction between two generic approaches. The (open quote)system-comparison(close q...

J. W. Andrews

1993-01-01

263

Test procedures and protocols: Their relevance to the figure of merit for thermal distribution systems. Volume 2: Appendices.  

National Technical Information Service (NTIS)

A conceptual framework is developed that categorizes measurement protocols for forced-air thermal distribution systems in small buildings. This framework is based on the distinction between two generic approaches. The (open quote)system-comparison(close q...

J. W. Andrews

1993-01-01

264

Support for User Interfaces for Distributed Systems  

NASA Technical Reports Server (NTRS)

An extensible Java(TradeMark) software framework supports the construction and operation of graphical user interfaces (GUIs) for distributed computing systems typified by ground control systems that send commands to, and receive telemetric data from, spacecraft. Heretofore, such GUIs have been custom built for each new system at considerable expense. In contrast, the present framework affords generic capabilities that can be shared by different distributed systems. Dynamic class loading, reflection, and other run-time capabilities of the Java language and JavaBeans component architecture enable the creation of a GUI for each new distributed computing system with a minimum of custom effort. By use of this framework, GUI components in control panels and menus can send commands to a particular distributed system with a minimum of system-specific code. The framework receives, decodes, processes, and displays telemetry data; custom telemetry data handling can be added for a particular system. The framework supports saving and later restoration of users configurations of control panels and telemetry displays with a minimum of effort in writing system-specific code. GUIs constructed within this framework can be deployed in any operating system with a Java run-time environment, without recompilation or code changes.

Eychaner, Glenn; Niessner, Albert

2005-01-01

265

Integrating CLIPS applications into heterogeneous distributed systems  

NASA Technical Reports Server (NTRS)

SOCIAL is an advanced, object-oriented development tool for integrating intelligent and conventional applications across heterogeneous hardware and software platforms. SOCIAL defines a family of 'wrapper' objects called agents, which incorporate predefined capabilities for distributed communication and control. Developers embed applications within agents and establish interactions between distributed agents via non-intrusive message-based interfaces. This paper describes a predefined SOCIAL agent that is specialized for integrating C Language Integrated Production System (CLIPS)-based applications. The agent's high-level Application Programming Interface supports bidirectional flow of data, knowledge, and commands to other agents, enabling CLIPS applications to initiate interactions autonomously, and respond to requests and results from heterogeneous remote systems. The design and operation of CLIPS agents are illustrated with two distributed applications that integrate CLIPS-based expert systems with other intelligent systems for isolating and mapping problems in the Space Shuttle Launch Processing System at the NASA Kennedy Space Center.

Adler, Richard M.

1991-01-01

266

Building a generalized distributed system model  

NASA Technical Reports Server (NTRS)

The key elements in the second year (1991-92) of our project are: (1) implementation of the distributed system prototype; (2) successful passing of the candidacy examination and a PhD proposal acceptance by the funded student; (3) design of storage efficient schemes for replicated distributed systems; and (4) modeling of gracefully degrading reliable computing systems. In the third year of the project (1992-93), we propose to: (1) complete the testing of the prototype; (2) enhance the functionality of the modules by enabling the experimentation with more complex protocols; (3) use the prototype to verify the theoretically predicted performance of locking protocols, etc.; and (4) work on issues related to real-time distributed systems. This should result in efficient protocols for these systems.

Mukkamala, R.

1992-01-01

267

Open quantum systems and Dicke superradiance  

NASA Astrophysics Data System (ADS)

We study generic features of open quantum systems embedded into a continuum of scattering wavefunctions and compare them with results discussed in optics. A dynamical phase transition may appear at high level density in a many-level system and also in a two-level system if the coupling W to the environment is complex and sufficiently large. Here nonlinearities occur. When W ij is imaginary, two singular (exceptional) points may exist. In the parameter range between these two points, width bifurcation occurs as function of a certain external parameter. A unitary representation of the S matrix allows to calculate the cross section for a two-level system, including at the exceptional point (double pole of the S matrix). The results obtained for the transition of level repulsion at small (real) W ij to width bifurcation at large (imaginary) W ij show qualitatively the same features that are observed experimentally in the transition from Autler-Townes splitting to electromagnetically induced transparency in optics. Fermi's golden rule holds only below the dynamical phase transition while it passes into an anti-golden rule beyond this transition. The results are generic and can be applied to the response of a complex open quantum system to the action of an external field (environment). They may be considered as a guideline for engineering and manipulating quantum systems in such a way that they can be used for applications with special requirements.

Eleuch, Hichem; Rotter, Ingrid

2014-03-01

268

Finite control in underdamped distributed parameter systems  

NASA Technical Reports Server (NTRS)

Specifically, a class of distributed parameter systems is defined using Hilbert space methods based on a partial differential equation model of a structure. In this space a simple, easy to check definition of underdamping is constructed based on the well known single degree of freedom concept of critical damping. It is then shown that if a given distributed parameter system satisfies this definition, each mode of the modal expansion of the solution is in fact an underdamped function of time. It is noted that a distributed parameter system which is underdamped is also uniformly exponentially stable. By appealing to the work of Gibson, a finite dimensional model of the system will yield satisfactory control laws. Furthermore, it is shown that the assumption of the underdamping also allows straightforward computation of rough bounds on the magnitude of the unmodeled or residual modes for a modal truncation scheme. Hence, underdamped systems are precisely that class of distributed parameter systems which are not likely to have spillover problems and which will yield convergence of finite dimensional control laws to control laws which are optimal for the full distributed parameter model of the system.

Inman, D. J.

1985-01-01

269

Aging, intergenerational distribution and public pension systems.  

PubMed

"This paper develops an intertemporal simulation model capable of addressing the macroeconomic and distributional effects of demographic shocks in a small open economy. Two sources of population aging are examined, viz. lower birth rates and prolonged expected lifetimes at retirement age. Due to strong expectational effects, both shocks are found to change average consumption in a downward direction, in the short run as well as in the long run. This effect is matched by a strong net acquisition of foreign assets. Furthermore, it turns out that the intergenerational distribution of the burden of adjusting to an aging population is strongly dependent on whether the benefit rate, the contribution rate, or the relative non-capital income of pensioners and workers is held fixed." PMID:12233622

Jensen, S E; Nielsen, S B

1993-01-01

270

Beam - plasma interaction and correlation phenomena in open Vlasov systems  

NASA Astrophysics Data System (ADS)

New results on collisionless beam - plasma dynamics in open systems with a non-equilibrium electron velocity distribution are reviewed and demonstrated via computer simulations based on the Vlasov - Poisson equations. It is shown that the known instability of the quasilinear theory (QLT) for sufficiently high wave amplitudes (in respect of the enhancement of wave - particle correlation and formation of space - time coherent structures) makes it invalid for describing plasma dynamics and turbulent transport in the majority of open plasma configurations. A typical example is the classical problem concerning a warm electron beam steadily injected into Maxwellian plasma half-space. Here, the real self-consistent relaxation picture is dramatically different from that predicted by QLT. The discovered fundamental deviations from QLT and their macroscopic consequences may be very important for a deep understanding of plasma transport processes, and are worthy of special laboratory testing. A short review of the present state of the problem and its background is given.

Sigov, Yurii S.; Levchenko, Vadim D.

1996-12-01

271

Distributed Access View Integrated Database (DAVID) system  

NASA Technical Reports Server (NTRS)

The Distributed Access View Integrated Database (DAVID) System, which was adopted by the Astrophysics Division for their Astrophysics Data System, is a solution to the system heterogeneity problem. The heterogeneous components of the Astrophysics problem is outlined. The Library and Library Consortium levels of the DAVID approach are described. The 'books' and 'kits' level is discussed. The Universal Object Typer Management System level is described. The relation of the DAVID project with the Small Business Innovative Research (SBIR) program is explained.

Jacobs, Barry E.

1991-01-01

272

REAL TIME SCHEDULING METHODS REQUIREMENTS IN DISTRIBUTED CONTROL SYSTEMS  

Microsoft Academic Search

Distributed control systems involve three main disciplines: control systems, real time systems, and communication systems. Control systems, due their stringent timing constraints, demand real time computing technology. Distributed control systems need communication systems when distributing sensors, actuators, the control procedures and data messaging. In general, demands of distributed control systems and properties of real time scheduling algorithms differ, for example,

Pau Martí; Ricard Villà; Josep M. Fuertes; Gerhard Fohler

2000-01-01

273

Operational Survivability in Gracefully Degrading Distributed Processing Systems.  

National Technical Information Service (NTIS)

A simulator was designed and developed which will model possible distributed system network topologies, distributed system application topologies and their effect on application system performance as the configuration of the distributed system network is ...

E. W. Martin

1980-01-01

274

Inverse engineering control in open quantum systems  

NASA Astrophysics Data System (ADS)

We propose a scheme for inverse engineering control in open quantum systems. Starting from an undetermined time evolution operator, a time-dependent Hamiltonian is derived in order to guide the system to attain an arbitrary target state at a predefined time. We calculate the fidelity of our inverse engineering control protocol in the presence of the noise with respect to the stochastic fluctuation of the linear parameters of the Hamiltonian during the time evolution. For a special family of Hamiltonians for two-level systems, we show that the control evolution of the system under noise can be categorized into two standard decohering processes: dephasing and depolarization, for both Markovian and non-Markovian conditions. In particular, we illustrate our formalism by analyzing the robustness of the engineered target state against errors. Moreover, we discuss the generalization of the inverse protocol for higher-dimensional systems.

Jing, Jun; Wu, Lian-Ao; Sarandy, Marcelo S.; Muga, J. Gonzalo

2013-11-01

275

Cooperative Autonomic Management in Dynamic Distributed Systems  

NASA Astrophysics Data System (ADS)

The centralized management of large distributed systems is often impractical, particularly when the both the topology and status of the system change dynamically. This paper proposes an approach to application-centric self-management in large distributed systems consisting of a collection of autonomic components that join and leave the system dynamically. Cooperative autonomic components self-organize into a dynamically created overlay network. Through local information sharing with neighbors, each component gains access to global information as needed for optimizing performance of applications. The approach has been validated and evaluated by developing a decentralized autonomic system consisting of multiple autonomic application managers previously developed for the In-VIGO grid-computing system. Using analytical results from complex random network and measurements done in a prototype system, we demonstrate the robustness, self-organization and adaptability of our approach, both theoretically and experimentally.

Xu, Jing; Zhao, Ming; Fortes, José A. B.

276

ON THE USE OF WEB SERVICES FOR BUILDING DISTRIBUTED AUTOMATION SYSTEMS  

Microsoft Academic Search

The paper discusses the applicability of Web services for building distributed automation systems and the benefits they bring. An adaptation of some of the well- proven enterprise architecture models and their applicability in distributed measurement is presented. The presented sample implementation is based on open and standardized approaches - high-level programming languages, object-oriented platforms, Internet technologies, and standardized communication interfaces.

MITKO SHOPOV; HRISTO MATEV; GRISHA SPASOV

2006-01-01

277

A New Approach to Load Flow Solutions for Radial Distribution System  

Microsoft Academic Search

This paper presents a new approach to load flow solutions for radial distribution system, in which the choice of the switches to be opened is based on the calculation of voltage at the buses, real and reactive power flowing through lines, real power losses and voltage deviation, using distribution load flow (DLF) program. In the process of load flow calculation,

T. Thakur; J. Dhiman

2006-01-01

278

Network Reconfiguration for Load Balancing in Radial Distribution Systems Using Genetic Algorithm  

Microsoft Academic Search

Network reconfiguration of a distribution system is an operation to alter the topological structure of distribution feeders by changing open \\/closed status of sectionalizing and tie switches. Network reconfiguration for time varying loads is very complex and extremely non-linear optimization, which can be effectively solved using genetic algorithm (GA). By transferring loads from the heavily loaded feeders to the lightly

P. V. Prasad; S. Sivanagaraju; N. Sreenivasulu

2007-01-01

279

Java-based automated test systems: management considerations for an open architecture for test  

Microsoft Academic Search

The advent of Sun's Java Platform is the culmination of years of research and evolution in multiple areas of software technology. This paper will propose an architecture with an open framework for ATS systems based on the emergence of Java as an open-systems, object-oriented computing environment. Java blends the features of a platform-independent runtime environment with object-oriented architecture and distributed

David E Tyler

1999-01-01

280

EDOS: Environment for the Development and Distribution of Open Source Software  

Microsoft Academic Search

The open-source software community is now comprised of a very large and growing number of contributors and users. The GNU\\/Linux operating system for instance has an estimated 18 million users worldwide and its contributing developers can be counted by thousands. The critical mass of contributors taking part in various open- source projects has helped to ensure high quality for open

Serge Abiteboul; Xavier Leroy; Boris Vrdoljak; Ciarán Bryce; Roberto Di Cosmo; Klaus R. Dittrich; Stéfane Fermigier; Tova Milo; Assaf Sagi; Yotam Shtossel; Stéphane Laurière; Frédéric Lepied; Radu Pop; Florent Villard; Eleonora Panto

281

Communication and Synchronization in Distributed Systems  

Microsoft Academic Search

Recent advances in technology have made the construction of general-purpose systems out of many small independent microprocessors feasible. One of the issue's concerning distributed systems is the question of appropriate language constructs for the handling of communication and synchronization. In his paper, \\

Abraham Silberschatz

1979-01-01

282

The advanced distributed ramp metering system (ARMS)  

Microsoft Academic Search

Ramp metering is an important technique to effectively utilize the freeway capacity by regulating the traffic flow of freeway entrance ramps. In this extended abstract, we discuss the outline of the free flow control algorithm of the Advanced distributed Ramp Metering System, ARMS, for the real-time control of freeway ramp metering systems. ARMS consists of three levels of control algorithms

Jyh-Charn Liu; Junguk Kim; Soojung Lee; T. Urbanik

1994-01-01

283

Cost and Performance of Distributed Photovoltaic Systems  

NASA Technical Reports Server (NTRS)

Lifetime Cost and Performance (LCP) model assists in design of Photovoltaic (PV) systems. LCP simulation of performance, cost and revenue streams associated with distributed PV power systems. Provides user with substantial flexibility in specifying technical and economic environment of PV application.

Borden, C. S.; Davisson, M. C.

1985-01-01

284

Distilled Water Distribution Systems. Laboratory Design Notes.  

ERIC Educational Resources Information Center

Factors concerning water distribution systems, including an evaluation of materials and a recommendation of materials best suited for service in typical facilities are discussed. Several installations are discussed in an effort to bring out typical features in selected applications. The following system types are included--(1) industrial…

Sell, J.C.

285

Data Integration in Computer Distributed Systems  

NASA Astrophysics Data System (ADS)

In this article the author analyze a problem of data integration in a computer distributed systems. Exchange of information between different levels in integrated pyramid of enterprise process is fundamental with regard to efficient enterprise work. Communication and data exchange between levels are not always the same cause of necessity of different network protocols usage, communication medium, system response time, etc.

Kwiecie?, B?a?ej

286

Real Time Distributed Control Systems Using RTAI  

Microsoft Academic Search

The paper outlines the design and implementation of the Real Time Application Interface (RTAI) for Linux, as used for high performance local\\/distributed control systems implemented on low cost off the shelf general purpose computers. Its native lean real time middleware layer is described along with its use in an advanced tool to easily manage and monitor complex networked control systems.

Lorenzo Dozio; Paolo Mantegazza

2003-01-01

287

Control technology development. [distributed parameter systems  

NASA Technical Reports Server (NTRS)

Static and dynamic control design approaches were developed for distributed parameter systems. A hardware flexible beam facility was constructed to demonstrate and verify the theoretical control concepts. Efforts were made in the area of model order estimation for control systems with uncertain or time varying parameters.

Rodriguez, G.

1981-01-01

288

Distribution control systems within the supply chain  

Microsoft Academic Search

Recommends a distribution control system which provides control of information and resource allocation throughout all stages of the supply chain, including delivery and sales order information, road traffic, vehicles, pallets and drivers. Describes how the system provides retrospective analysis and forward planning facilities and can be tailored to the specific needs of individual user companies.

Ian Wilson

1995-01-01

289

Neutral Particle Beam Distributed Data Acquisition System.  

National Technical Information Service (NTIS)

A distributed data acquisition system has been designed to support experiments at the Argonne Neutral Particle Beam Accelerator. The system uses a host VAXstation II/GPX computer acting as an experimenter's station linked via Ethernet with multiple MicroV...

R. T. Daly M. R. Kraimer A. H. Novick

1987-01-01

290

Design considerations for distributed microsensor systems  

Microsoft Academic Search

Wireless distributed microsensor systems will enable the reliable monitoring and control of a variety of applications that range from medical and home security to machine diagnosis, chemical\\/biological detection and other military applications. The sensors have to be designed in a highly integrated fashion, optimizing across all levels of system abstraction, with the goal of minimizing energy dissipation. This paper addresses

Anantha Chandrakasan; Rajeevain Amirtharajah; Seonghwan Cho; James Goodman; Gangadhar Konduri; Joanna Kulik; Wendi Rabiner; Alice Wang

1999-01-01

291

Experiences with the Amoeba distributed operating system  

Microsoft Academic Search

The Amoeba project is a research effort aimed at understanding how to connect multiple computers in a seamless way [16, 17, 26, 27, 31]. The basic idea is to provide the users with the illusion of a single powerful timesharing system, when, in fact, the system is implemented on a collection of machines, potentially distributed among several countries. This research

Andrew S. Tanenbaum; Robbert van Renesse; Hans van Staveren; Gregory J. Sharp; Sape J. Mullender; Jack Jansen; Rossum van Guido

1990-01-01

292

Policy Driven Management for Distributed Systems  

Microsoft Academic Search

Separating management policy from the automated managers which interpret the policy facilitates the dynamic change of behaviour of a distributed management system. This permits it to adapt to evolutionary changes in the system being managed and to new application requirements. Changing the behaviour of automated managers can be achieved by changing the policy without have to reimplement them - this

Morris Sloman

1994-01-01

293

An Evaluation of a Distributed Learning System.  

ERIC Educational Resources Information Center

A survey of 306 undergraduate and graduate students, focus groups, and lecturers' reports evaluated a Web-enabled distributed learning system. The system was popular with students, flexible, self-paced, and empowering; technical support difficulties generated frustration. There was less interaction than desired and a lack of instant feedback and…

Lawther, Peter M; Walker, Derek H. T.

2001-01-01

294

Detection of Mutual Inconsistency in Distributed Systems  

Microsoft Academic Search

Many distributed systems are now being developed to provide users with convenient access to data via some kind of communications network. In many cases it is desirable to keep the system functioning even when it is partitioned by network failures. A serious problem in this context is how one can support redundant copies of resources such as files (for the

Douglas Stott Parker Jr.; Gerald J. Popek; Gerard Rudisin; Allen Stoughton; Bruce J. Walker; Evelyn Walton; Johanna M. Chow; David A. Edwards; Stephen Kiser; Charles S. Kline

1983-01-01

295

Elections in a Distributed Computing System  

Microsoft Academic Search

Abstract-After afailure occurs inadistributed computing system, itisoften necessary toreorganize theactive nodes sothat they can continue toperform auseful task. Thefirst step insuch areorgani- zation orreconfiguration istoelect acoordinator nodetomanage the operation. Thispaper discusses suchelections andreorganizations. Twotypes ofreasonable failure environments arestudied. Foreach environment assertions which define themeaning ofanelection are presented. Anelection algorithm whichsatisfies theassertions is presented foreachenvironment. IndexTerms-Crash recovery, distributed computing systems,

Hector Garcia-molina

1982-01-01

296

Measurements of a Distributed File System  

Microsoft Academic Search

We analyzed the user-level file access patterns and caching behavior of the Sprite distributed file system. The first part of our analysis repeated a study done in 1985 of the: BSD UNIX file system. We found that file throughput has increased by a factor of 20 to an average of 8 Kbytes per second per active user over 10-minute intervals,

Mary G. Baker; John H. Hartman; Michael D. Kupfer; Ken W. Shirriff; John K. Ousterhout

1991-01-01

297

Design Considerations for Distributed Microsensor Systems  

Microsoft Academic Search

Wireless distributed microsensor systems will enable the reliable monitoring and control of a variety of applica- tions that range from medical and home security to machine diagnosis, chemical\\/biological detection and other military applications. The sensors have to be designed in a highly integrated fashion, optimizing across all levels of system abstraction, with the goal of minimiz- ing energy dissipation. This

Anantha Chandrakasan; Rajeevan Amirtharajah; SeongHwan Cho; James Goodman; Gangadhar Konduri; Joanna Kulik; Wendi Rabiner; Alice Wang

2000-01-01

298

Understanding fault-tolerant distributed systems  

Microsoft Academic Search

We propose a small number of basic concepts that can be used to explain thearchitecture of fault-tolerant distributed systems and we discuss a list of architecturalissues that we find useful to consider when designing or examining suchsystems. For each issue we present known solutions and design alternatives, wediscuss their relative merits and we give examples of systems which adopt oneapproach

Flavin Cristian

1991-01-01

299

Ontology-based distributed intrusion detection system  

Microsoft Academic Search

In this paper we discussed about utilizing methods and techniques of semantic web in the Intrusion Detection Systems. To extract semantic relations between computer attacks and intrusions in a Distributed Intrusion Detection System, we use ontology. Protege software is our selected software for building ontology. In addition, we utilized Jena framework to make interaction between MasterAgent and attacks ontology. Our

F. Abdoli; M. Kahani

2009-01-01

300

Performance Monitoring of Distributed Data Processing Systems  

NASA Technical Reports Server (NTRS)

Test and checkout systems are essential components in ensuring safety and reliability of aircraft and related systems for space missions. A variety of systems, developed over several years, are in use at the NASA/KSC. Many of these systems are configured as distributed data processing systems with the functionality spread over several multiprocessor nodes interconnected through networks. To be cost-effective, a system should take the least amount of resource and perform a given testing task in the least amount of time. There are two aspects of performance evaluation: monitoring and benchmarking. While monitoring is valuable to system administrators in operating and maintaining, benchmarking is important in designing and upgrading computer-based systems. These two aspects of performance evaluation are the foci of this project. This paper first discusses various issues related to software, hardware, and hybrid performance monitoring as applicable to distributed systems, and specifically to the TCMS (Test Control and Monitoring System). Next, a comparison of several probing instructions are made to show that the hybrid monitoring technique developed by the NIST (National Institutes for Standards and Technology) is the least intrusive and takes only one-fourth of the time taken by software monitoring probes. In the rest of the paper, issues related to benchmarking a distributed system have been discussed and finally a prescription for developing a micro-benchmark for the TCMS has been provided.

Ojha, Anand K.

2000-01-01

301

Adaptive, Distributed Control of Constrained Multi-Agent Systems.  

National Technical Information Service (NTIS)

Product Distribution (PO) theory was recently developed as a broad framework for analyzing and optimizing distributed systems. Here we demonstrate its use for adaptive distributed control of Multi-Agent Systems (MASS), i.e., for distributed stochastic opt...

S. Bieniawski

2004-01-01

302

Exploiting virtual synchrony in distributed systems  

NASA Technical Reports Server (NTRS)

Applications of a virtually synchronous environment are described for distributed programming, which underlies a collection of distributed programming tools in the ISIS2 system. A virtually synchronous environment allows processes to be structured into process groups, and makes events like broadcasts to the group as an entity, group membership changes, and even migration of an activity from one place to another appear to occur instantaneously, in other words, synchronously. A major advantage to this approach is that many aspects of a distributed application can be treated independently without compromising correctness. Moreover, user code that is designed as if the system were synchronous can often be executed concurrently. It is argued that this approach to building distributed and fault tolerant software is more straightforward, more flexible, and more likely to yield correct solutions than alternative approaches.

Birman, Kenneth P.; Joseph, Thomas A.

1987-01-01

303

Distributed algorithms for monitoring and control of electric power transmission and distribution systems  

Microsoft Academic Search

The benefits of distributed computing systems are massively increased computing power and improved reliability. Distributed computing systems are particularly attractive for monitoring and control of large-scale electric power transmission and distribution systems. In this dissertation two aspects of distributed computing have been investigated. First, a distributed software model for the implementation of network security functions in energy management systems is

Neyer

1989-01-01

304

Information distribution in distributed microprocessor based flight control systems  

NASA Technical Reports Server (NTRS)

This paper presents an optimal control theory that accounts for variable time intervals in the information distribution to control effectors in a distributed microprocessor based flight control system. The theory is developed using a linear process model for the aircraft dynamics and the information distribution process is modeled as a variable time increment process where, at the time that information is supplied to the control effectors, the control effectors know the time of the next information update only in a stochastic sense. An optimal control problem is formulated and solved that provides the control law that minimizes the expected value of a quadratic cost function. An example is presented where the theory is applied to the control of the longitudinal motions of the F8-DFBW aircraft. Theoretical and simulation results indicate that, for the example problem, the optimal cost obtained using a variable time increment Markov information update process where the control effectors know only the past information update intervals and the Markov transition mechanism is almost identical to that obtained using a known uniform information update interval.

Montgomery, R. C.; Lee, P. S.

1977-01-01

305

Neutral particle beam distributed data acquisition system  

SciTech Connect

A distributed data acquisition system has been designed to support experiments at the Argonne Neutral Particle Beam Accelerator. The system uses a host VAXstation II/GPX computer acting as an experimenter's station linked via Ethernet with multiple MicroVAX IIs and rtVAXs dedicated to acquiring data and controlling hardware at remote sites. This paper describes the hardware design of the system, the applications support software on the host and target computers, and the real-time performance.

Daly, R.T.; Kraimer, M.R.; Novick, A.H.

1987-08-01

306

Neutral particle beam distributed data acquisition system  

SciTech Connect

A distributed data acquisition system has been designed to support experiments at the Argonne Neutral Particle Beam Accelerator. The system uses a host VAXstation II/GPX computer acting as an experimenter's station linked via Ethernet with multiple MicroVAX IIs and rtVAXs dedicated to acquiring data and controlling hardware at remote sites. This paper describes the hardware design of the system, the applications support software on the host and target computers, and the real-time performance.

Daly, R.T.; Kraimer, M.R.; Novick, A.H.

1987-01-01

307

Neutral particle beam distributed data acquisition system  

Microsoft Academic Search

A distributed data acquisition system has been designed to support experiments at the Argonne Neutral Particle Beam Accelerator. The system uses a host VAXstation II\\/GPX computer acting as an experimenter's station linked via Ethernet with multiple MicroVAX IIs and rtVAXs dedicated to acquiring data and controlling hardware at remote sites. This paper describes the hardware design of the system, the

R. T. Daly; M. R. Kraimer; A. H. Novick

1987-01-01

308

Modeling risk in distributed healthcare information systems.  

PubMed

This paper presents a modeling approach for performing a risk analysis study of networked healthcare information systems. The proposed method is based on CRAMM for studying the assets, threats and vulnerabilities of the distributed information system, and models their interrelationships using Bayesian networks. The most critical events are identified and prioritized, based on "what - if" studies of system operation. The proposed risk analysis framework has been applied to a healthcare information network operating in the North Aegean Region in Greece. PMID:17945902

Maglogiannis, Ilias; Zafiropoulos, Elias

2006-01-01

309

Fault-tolerant Distributed Computer Systems  

NSDL National Science Digital Library

Distributed systems are difficult to build and understand, for all sorts of reasons. Failures are common in large systems, and we can't let them shut the application down; a well-engineered system will tolerate failures and repair any damage they caused. A single event, perceived at multiple locations, may not be totally ordered with respect to other, conflicting, events. Networks have annoying connectivity and bandwidth properties, that force the designer to confront challenging engineering trade-offs.

Birman, Ken

2009-02-17

310

Power System Information Delivering System Based on Distributed Object  

NASA Astrophysics Data System (ADS)

In recent years, improvement in computer performance and development of computer network technology or the distributed information processing technology has a remarkable thing. Moreover, the deregulation is starting and will be spreading in the electric power industry in Japan. Consequently, power suppliers are required to supply low cost power with high quality services to customers. Corresponding to these movements the authors have been proposed SCOPE (System Configuration Of PowEr control system) architecture for distributed EMS/SCADA (Energy Management Systems / Supervisory Control and Data Acquisition) system based on distributed object technology, which offers the flexibility and expandability adapting those movements. In this paper, the authors introduce a prototype of the power system information delivering system, which was developed based on SCOPE architecture. This paper describes the architecture and the evaluation results of this prototype system. The power system information delivering system supplies useful power systems information such as electric power failures to the customers using Internet and distributed object technology. This system is new type of SCADA system which monitors failure of power transmission system and power distribution system with geographic information integrated way.

Tanaka, Tatsuji; Tsuchiya, Takehiko; Tamura, Setsuo; Seki, Tomomichi; Kubota, Kenji

311

Cardea: Dynamic Access Control in Distributed Systems  

NASA Technical Reports Server (NTRS)

Modern authorization systems span domains of administration, rely on many different authentication sources, and manage complex attributes as part of the authorization process. This . paper presents Cardea, a distributed system that facilitates dynamic access control, as a valuable piece of an inter-operable authorization framework. First, the authorization model employed in Cardea and its functionality goals are examined. Next, critical features of the system architecture and its handling of the authorization process are then examined. Then the S A M L and XACML standards, as incorporated into the system, are analyzed. Finally, the future directions of this project are outlined and connection points with general components of an authorization system are highlighted.

Lepro, Rebekah

2004-01-01

312

Oblique color vision in an open-habitat bird: spectral sensitivity, photoreceptor distribution and behavioral implications.  

PubMed

Color vision is not uniform across the retina because of differences in photoreceptor density and distribution. Retinal areas with a high density of cone photoreceptors may overlap with those with a high density of ganglion cells, increasing hue discrimination. However, there are some exceptions to this cell distribution pattern, particularly in species with horizontal visual streaks (bands of high ganglion cell density across the retina) that live in open habitats. We studied the spectral sensitivity and distribution of cone photoreceptors involved in chromatic and achromatic vision in the Canada goose (Branta canadiensis), which possesses an oblique rather than horizontal visual streak at the ganglion cell layer. Using microspectrophotometry, we found that the Canada goose has a violet-sensitive visual system with four visual pigments with absorbance peaks at 409, 458, 509 and 580 nm. The density of most cones involved in chromatic and achromatic vision peaked along a band across the retina that matched the oblique orientation of the visual streak. With the information on visual sensitivity, we calculated chromatic and achromatic contrasts of different goose plumage regions. The regions with the highest visual saliency (cheek, crown, neck and upper tail coverts) were the ones involved in visual displays to maintain flock cohesion. The Canada goose oblique visual streak is the retinal center for chromatic and achromatic vision, allowing individuals to sample the sky and the ground simultaneously or the horizon depending on head position. Overall, our results show that the Canada goose visual system has features that make it rather different from that of other vertebrates living in open habitats. PMID:22956248

Moore, Bret A; Baumhardt, Patrice; Doppler, Megan; Randolet, Jacquelyn; Blackwell, Bradley F; DeVault, Travis L; Loew, Ellis R; Fernández-Juricic, Esteban

2012-10-01

313

Vision for an Open, Global Greenhouse Gas Information System (GHGIS)  

NASA Astrophysics Data System (ADS)

Over the next few years, an increasing number of entities ranging from international, national, and regional governments, to businesses and private land-owners, are likely to become more involved in efforts to limit atmospheric concentrations of greenhouse gases. In such a world, geospatially resolved information about the location, amount, and rate of greenhouse gas (GHG) emissions will be needed, as well as the stocks and flows of all forms of carbon through the earth system. The ability to implement policies that limit GHG concentrations would be enhanced by a global, open, and transparent greenhouse gas information system (GHGIS). An operational and scientifically robust GHGIS would combine ground-based and space-based observations, carbon-cycle modeling, GHG inventories, synthesis analysis, and an extensive data integration and distribution system, to provide information about anthropogenic and natural sources, sinks, and fluxes of greenhouse gases at temporal and spatial scales relevant to decision making. The GHGIS effort was initiated in 2008 as a grassroots inter-agency collaboration intended to identify the needs for such a system, assess the capabilities of current assets, and suggest priorities for future research and development. We will present a vision for an open, global GHGIS including latest analysis of system requirements, critical gaps, and relationship to related efforts at various agencies, the Group on Earth Observations, and the Intergovernmental Panel on Climate Change.

Duren, R. M.; Butler, J. H.; Rotman, D.; Ciais, P.; Greenhouse Gas Information System Team

2010-12-01

314

46 CFR 120.376 - Grounded distribution systems (Neutral grounded).  

Code of Federal Regulations, 2010 CFR

...ELECTRICAL INSTALLATION Power Sources and Distribution Systems § 120...If a grounded distribution system is provided...of the number of power sources. This...Each propulsion, power, lighting, or distribution system having...

2010-10-01

315

46 CFR 183.376 - Grounded distribution systems (neutral grounded).  

Code of Federal Regulations, 2010 CFR

...ELECTRICAL INSTALLATION Power Sources and Distribution Systems § 183...If a grounded distribution system is provided...of the number of power sources. This...Each propulsion, power, lighting, or distribution system having...

2009-10-01

316

46 CFR 120.376 - Grounded distribution systems (Neutral grounded).  

Code of Federal Regulations, 2010 CFR

...ELECTRICAL INSTALLATION Power Sources and Distribution Systems § 120...If a grounded distribution system is provided...of the number of power sources. This...Each propulsion, power, lighting, or distribution system having...

2009-10-01

317

46 CFR 183.376 - Grounded distribution systems (neutral grounded).  

Code of Federal Regulations, 2010 CFR

...ELECTRICAL INSTALLATION Power Sources and Distribution Systems § 183...If a grounded distribution system is provided...of the number of power sources. This...Each propulsion, power, lighting, or distribution system having...

2010-10-01

318

47 CFR 73.6023 - Distributed transmission systems.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Distributed transmission systems. 73.6023 Section...Stations § 73.6023 Distributed transmission systems. Station licensees...television channel in a distributed transmission system. [73 FR...

2010-10-01

319

47 CFR 73.6023 - Distributed transmission systems.  

Code of Federal Regulations, 2010 CFR

...2009-10-01 false Distributed transmission systems. 73.6023 Section...Stations § 73.6023 Distributed transmission systems. Station licensees...television channel in a distributed transmission system. [73 FR...

2009-10-01

320

47 CFR 73.6023 - Distributed transmission systems.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Distributed transmission systems. 73.6023 Section...Stations § 73.6023 Distributed transmission systems. Station licensees...television channel in a distributed transmission system. [73 FR...

2013-10-01

321

49 CFR 192.723 - Distribution systems: Leakage surveys.  

Code of Federal Regulations, 2013 CFR

...false Distribution systems: Leakage surveys. 192.723 Section 192.723 Transportation...723 Distribution systems: Leakage surveys. (a) Each operator of a distribution system shall conduct periodic leakage surveys in accordance with this...

2013-10-01

322

Open systems architecture solutions for military avionics testing  

Microsoft Academic Search

Raytheon makes extensive use of open systems architecture methods in developing special test equipment (STE) for testing military avionics equipment. Such use has resulted in significant cost and schedule savings in the development of production test equipment for radar and infrared systems. With open systems architectures, a test system can be assembled using COTS products. This brings economies of scale

Stephen Pizzica

2001-01-01

323

Open online transaction processing with the TUXEDO system  

Microsoft Academic Search

The authors present an overview of the TUXEDO Enterprise Transaction Processing System, which provides a UNIX system-based transaction processing monitor System\\/T, designed to enable the integration of many different components of online transaction processing (OLTP) in an open systems environment. They discuss the requirements driving open OLTP in today's market and review the TUXEDO products designed to meet those requirements

J. M. Andrade; M. T. Carges; M. R. MacBlane

1992-01-01

324

Switch placement to improve system reliability for radial distribution systems with distributed generation  

Microsoft Academic Search

To improve system reliability for radial distribution systems with distributed generation (DG) under fault conditions, switch placement schemes are proposed to form self-supported areas after fault isolation. Customer priority is also considered in this problem. The switch placement problem is formulated as a nondifferentiable, multiobjective optimization problem. Graph-based algorithms, which incorporate direct load control, are developed to locate switches. Their

Yiming Mao; Karen N. Miu

2003-01-01

325

A Web-Service-based Open-Systems Architecture for Achieving Heterogeneity in Synchronous Collaborative Editing Systems  

Microsoft Academic Search

Motivated by the need to support concurrent, collaborative access to shared documents, we have designed and validated an architecture that integrates existing and familiar systems for client editing software and document repositories. Through Web-services, we achieve an open system wherein numerous clients can use varied editing tools to fit their preferences and access documents distributed on a heterogeneous collection of

Jon A Preston; Sushil K Prasad

326

High temperature hot water distribution system study  

SciTech Connect

The existing High Temperature Hot Water (HTHW) Distribution System has been plagued with design and construction deficiencies since startup of the HTHW system, in October 1988. In October 1989, after one year of service, these deficiencies were outlined in a technical evaluation. The deficiencies included flooded manholes, sump pumps not hooked up, leaking valves, contaminated HTHW water, and no cathodic protection system. This feasibility study of the High Temperature Hot Water (HTHW) Distribution System was performed under Contract No. DACA0l-94-D-0033, Delivery Order 0013, Modification 1, issued to EMC Engineers, Inc. (EMC), by the Norfolk District Corps of Engineers, on 25 April 1996. The purpose of this study was to determine the existing conditions of the High Temperature Hot Water Distribution System, manholes, and areas of containment system degradation. The study focused on two areas of concern, as follows: * Determine existing conditions and areas of containment system degradation (leaks) in the underground carrier pipes and protective conduit. * Document the condition of underground steel and concrete manholes. To document the leaks, a site survey was performed, using state-of-the-art infrared leak detection equipment and tracer gas leak detection equipment. To document the condition of the manholes, color photographs were taken of the insides of 125 manholes, and notes were made on the condition of these manholes.

NONE

1996-12-01

327

MIMOSA: Conceptual modelling of medical image management in an open system architecture  

Microsoft Academic Search

Due to improvements in technology of information processing systems, more and more valuable information is generated each day, in biomedical institutions. Thus, providing a mutual understanding between all users is vital in health care information systems, either paper or computer based. This state of interoperability can be reached by designing an open environment for managing, exchanging and distributing biomedical images

F. AUBRyl; V. Chameroy; A. Giron; R. Di Paola; B. Gibaud; y. Bizais; D. Vital; R. Lienard; A. Todd-Pokropek; R. Kanz; F. Deconinck; O. Ratib

1992-01-01

328

Deceit: A flexible distributed file system  

NASA Technical Reports Server (NTRS)

Deceit, a distributed file system (DFS) being developed at Cornell, focuses on flexible file semantics in relation to efficiency, scalability, and reliability. Deceit servers are interchangeable and collectively provide the illusion of a single, large server machine to any clients of the Deceit service. Non-volatile replicas of each file are stored on a subset of the file servers. The user is able to set parameters on a file to achieve different levels of availability, performance, and one-copy serializability. Deceit also supports a file version control mechanism. In contrast with many recent DFS efforts, Deceit can behave like a plain Sun Network File System (NFS) server and can be used by any NFS client without modifying any client software. The current Deceit prototype uses the ISIS Distributed Programming Environment for all communication and process group management, an approach that reduces system complexity and increases system robustness.

Siegel, Alex; Birman, Kenneth; Marzullo, Keith

1989-01-01

329

Security Enhancements for Distributed Control Systems  

Microsoft Academic Search

Security enhancements for distributed control systems (DCSs) must be sensitive to operational issues, especially availability.\\u000a This paper presents three security enhancements for DCSs that satisfy this requirement: end-to-end security for DCS protocol\\u000a communications, role-based authorization to control access to devices and prevent unauthorized changes to operational parameters,\\u000a and reduced operating system kernels for enhanced device security. The security enhancements have

Jeffrey L. Hieb; James H. Graham; Sandip C. Patel

2007-01-01

330

Programming model for distributed intelligent systems  

NASA Technical Reports Server (NTRS)

A programming model and architecture which was developed for the design and implementation of complex, heterogeneous measurement and control systems is described. The Multigraph Architecture integrates artificial intelligence techniques with conventional software technologies, offers a unified framework for distributed and shared memory based parallel computational models and supports multiple programming paradigms. The system can be implemented on different hardware architectures and can be adapted to strongly different applications.

Sztipanovits, J.; Biegl, C.; Karsai, G.; Bogunovic, N.; Purves, B.; Williams, R.; Christiansen, T.

1988-01-01

331

Resilient Concurrency Control in Distributed Database Systems  

Microsoft Academic Search

This paper presents the resiliency features of the optimistic approach to concurrency control and demonstrates how it lends itself to a design of a reliable distributed database system. The validation of concurrency control, integrity control, and atomicity control has been integrated. This integration provides a high degree of concurrency and continuity of operations in spite of failures of transactions, processors,

Bharat Bhargava

1983-01-01

332

DISTRIBUTION SYSTEM: COST OF REPAIR AND REPLACEMENT  

EPA Science Inventory

The Safe Drinking Water Act of 1974 mandates that EPA be concerned with the supply of potable water to the consumer. Although most emphasis has been placed on water quality as it leaves the treatment plant interest is increasing in the role of the distribution system in causing w...

333

DISTRIBUTION SYSTEM RELIABILITY ANALYSIS USING A MICROCOMPUTER  

EPA Science Inventory

Distribution system reliability for most utilities is maintained by the knowledge of a few key personnel. Generally, these water maintenance personnel use a good memory, repair records, a large wall map and a hydraulic model of the larger transmission mains to help identify probl...

334

Composite fault location for Distribution Management Systems  

Microsoft Academic Search

The problem of fault location is an integral part of Distribution Management System (DMS) solutions. This paper presents a method of locating fault in unsymmetrical networks, including both radial and meshed parts of the network. The real-time information regarding the topological condition of the network and the status updates of the Fault Indicators are used as input to the fault

I. Dzafic; P. Mohapatra; H. T. Neisius

2010-01-01

335

Body-Worn Distributed MIMO System  

Microsoft Academic Search

In this paper, we analyze the performance of novel wearable multiple-input-multiple-output (MIMO) systems, which consist of multiple electrotextile wearable antennas distributed at different locations on human clothing. For wearable applications, a semidirectional radiation pattern of the wearable patch antenna is preferred over an omnidirectional radiation of conventional dipole antennas to avoid unnecessary radiation exposure to the human body and radiation

Yuehui Ouyang; David J. Love; William J. Chappell

2009-01-01

336

Process Partitioning for Distributed Embedded Systems  

Microsoft Academic Search

We present a new technique for partitioning processes in distributed embedded systems. Our heuristic algorithm minimizes both context switch and communication overhead under real-time deadline and process size constraints; it also tries to allocate functions to processors which are well-suited to that function. The algorithm analyzes the sensitivity of the latency of the task graph to changes in vertices hierarchical

Junwei Hou; Wayne Wolf

1996-01-01

337

Optimal capacitor placement on radial distribution systems  

Microsoft Academic Search

Capacitor placement problem on radial distribution systems is formulated and a solution algorithm is proposed. The location, type, and size of capacitors, voltage constraints, and load variations are considered in the problem. The objective of capacitor placement is peak power and energy loss reduction by raking into account the cost of capacitors. The problem is formulated as a mixed integer

M. E. Baran; F. F. Wu

1989-01-01

338

Network Coding for Distributed Storage Systems  

Microsoft Academic Search

Peer-to-peer distributed storage systems pro- vide reliable access to data through redundancy spread over nodes across the Internet. A key goal is to minimize the amount of bandwidth used to maintain that redundancy. Storing a file using an erasure code, in fragments spread across nodes, promises to require less redundancy and hence less maintenance bandwidth than simple replication to provide

Alexandros G. Dimakis; Brighten Godfrey; Martin J. Wainwright; Kannan Ramchandran

2007-01-01

339

Optimal power flow in radial distribution systems  

Microsoft Academic Search

Radial distribution systems (RDS) have lines with high R\\/X ratios and hence Newton based methods were not reliable to solve their set of bus power balance equations. Historically, a recursive solution method using a set of voltage equations and its variants are very popular to determine a voltage solution of a RDS. Consequently, use of classical optimization was not possible.

B. Venkatesh

2010-01-01

340

Distributed Control System for a Humanoid Robot  

Microsoft Academic Search

A humanoid robot generally has more than thirty DOFs to be controlled in real-time and needs to deal with information of multiple sensors such as encoders, force, gyro, acceleration and vision sensors. Therefore an effective control system is crucial for the humanoid robot. In this paper, we propose a distributed control architecture for humanoid robots based on the combination of

Zhangguo Yu; Qiang Huang; Jianxi Li; Qing Shi; Xuechao Chen; Kejie Li

2007-01-01

341

What future for the distributed systems annex?  

Microsoft Academic Search

In this paper, we report our experience as implementors and users of the Ada 95 Distributed Systems Annex (annex E of the Ada reference manual). We identify the principal strengths and weaknesses of the annex, and make some proposals to improve it either immediately or for the next revision of the language (Ada0X). Our goal is to get an annex

Laurent Pautet; Samuel Tardieu

1999-01-01

342

Reliability Modeling in Spatially Distributed Logistics Systems  

Microsoft Academic Search

This article proposes methods for modeling service reliability in a supply chain. The logistics system in a supply chain typically consists of thousands of retail stores along with multiple distribution centers (DC). Products are transported between DC & stores through multiple routes. The service reliability depends on DC location layouts, distances from DC to stores, time requirements for product replenishing

Ni Wang; Jye-Chyi Lu; Paul Kvam

2006-01-01

343

Frangipani: A Scalable Distributed File System  

Microsoft Academic Search

The ideal distributed file system would provide all its users with co- herent, shared access to the same set of files,yet would be arbitrarily scalable to provide more storage space and higher performance to a growing user community. It would be highly available in spite of component failures. It would require minimal human administra- tion, and administration would not become

Chandramohan A. Thekkath; Timothy Mann; Edward K. Lee

1997-01-01

344

FOR RELIABLE DISTRIBUTED COMPUTER CONTROLLED SYSTEMS  

Microsoft Academic Search

1. Abstract In Distributed Computer-Controlled Systems (DCCS), both real-time and dependability (reliability and availability) requirements are of major concern. Architectures for DCCS must be designed considering the integration of processing nodes and the underlying communication infrastructure. Such integration must be provided by appropriate software support services. In this paper, an arch itecture for DCCS is presented, its structure is outlined,

Luís Miguel Pinho; Francisco Vasques

345

METALS DISTRIBUTIONS IN ACTIVATED SLUDGE SYSTEMS  

EPA Science Inventory

This project developed models to predict the distribution of metals in activated sludge system process streams. The data used to develop the models were obtained through extended pilot studies from a previous project. The objectives of the study were to evaluate the effects of wa...

346

Analytical Models for Distributed Grounding Systems  

Microsoft Academic Search

Simple lumped-parameter circuit models for distributed grounding systems have been developed from the truncation of theoretical solutions. The simplest model utilizes two time constants; one for relatively short times and one for relatively long times. The variation of soil conductivity and permittivity with frequency is estimated and taken into account in the determination of the time constants. Estimating curves for

S. S. Devgan; E. R. Whitehead

1973-01-01

347

A remote monitoring system for Open Ocean Aquaculture  

Microsoft Academic Search

The purpose of this project was to determine the practicality and characteristics of a remote monitoring system for an open ocean aquaculture fish cage. The Open Ocean Aquaculture program at the University of New Hampshire currently uses two fish cages to develop the technology and methodology to raise finned fish in the open ocean. The cages are located about six

A. P. M. Michel; K. L. Croff; K. W. McLetchie; J. D. Irish

2002-01-01

348

System Issues in Implementing High Speed Distributed Parallel Storage Systems  

Microsoft Academic Search

In this paper we describe several aspects of implementing a high speed network-based distributed application. We describe the design and implementation of a distributed parallel storage system that uses high speed ATM networks as a key element of the architecture. The architecture provides what amounts to a collection of network-based disk block servers, and an associated name server that provides

Bill Johnston; Brian Tierney; Gary Hoo; Guojun Jin; Hanan Herzog; Jason Lee

1994-01-01

349

Systems Modelling and Identification in CAN based Distributed Control Systems  

Microsoft Academic Search

Distributed control systems performance can be affected by the occurrence of jitter in the messages that carry relevant data such as sample and actuation variables. This jitter comes from the influence of messages from other sources and thus depends on factors such as the distribution of controller tasks and the medium access control used in the network. When a CAN-

Alexandre Manuel Mot; Pedro Fonseca; José Alberto Fonseca

350

Design of intelligent distributed control systems: a dependability point of view  

Microsoft Academic Search

The use of fieldbuses and the emergence of intelligent sensors and actuators are opening up new possibilities for distributed control systems, but are also introducing additional constraints in terms of achieving dependability objectives. The type of production environment will greatly determine the predominant criterion for an automatic control system, i.e. reliability, availability, maintainability, safety, etc. On the other hand, the

Joseph Ciccotelli; Blaise Conrard; Mireille Bayart

2004-01-01

351

Data reprocessing on worldwide distributed systems  

SciTech Connect

The D0 experiment faces many challenges in terms of enabling access to large datasets for physicists on four continents. The strategy for solving these problems on worldwide distributed computing clusters is presented. Since the beginning of Run II of the Tevatron (March 2001) all Monte-Carlo simulations for the experiment have been produced at remote systems. For data analysis, a system of regional analysis centers (RACs) was established which supply the associated institutes with the data. This structure, which is similar to the tiered structure foreseen for the LHC was used in Fall 2003 to reprocess all D0 data with a much improved version of the reconstruction software. This makes D0 the first running experiment that has implemented and operated all important computing tasks of a high energy physics experiment on systems distributed worldwide.

Wicke, Daniel; /Fermilab

2004-12-01

352

PILOT: An intelligent distributed operations support system  

NASA Technical Reports Server (NTRS)

The Real-Time Data System (RTDS) project is exploring the application of advanced technologies to the real-time flight operations environment of the Mission Control Centers at NASA's Johnson Space Center. The system, based on a network of engineering workstations, provides services such as delivery of real time telemetry data to flight control applications. To automate the operation of this complex distributed environment, a facility called PILOT (Process Integrity Level and Operation Tracker) is being developed. PILOT comprises a set of distributed agents cooperating with a rule-based expert system; together they monitor process operation and data flows throughout the RTDS network. The goal of PILOT is to provide unattended management and automated operation under user control.

Rasmussen, Arthur N.

1993-01-01

353

Laser spark distribution and ignition system  

DOEpatents

A laser spark distribution and ignition system that reduces the high power optical requirements for use in a laser ignition and distribution system allowing for the use of optical fibers for delivering the low peak energy pumping pulses to a laser amplifier or laser oscillator. An optical distributor distributes and delivers optical pumping energy from an optical pumping source to multiple combustion chambers incorporating laser oscillators or laser amplifiers for inducing a laser spark within a combustion chamber. The optical distributor preferably includes a single rotating mirror or lens which deflects the optical pumping energy from the axis of rotation and into a plurality of distinct optical fibers each connected to a respective laser media or amplifier coupled to an associated combustion chamber. The laser spark generators preferably produce a high peak power laser spark, from a single low power pulse. The laser spark distribution and ignition system has application in natural gas fueled reciprocating engines, turbine combustors, explosives and laser induced breakdown spectroscopy diagnostic sensors.

Woodruff, Steven (Morgantown, WV); McIntyre, Dustin L. (Morgantown, WV)

2008-09-02

354

High-performance computing and distributed systems  

SciTech Connect

We present a scenario for a fully distributed computing environment in which computing, storage, and I/O elements are configured on demand into virtual systems'' that are optimal for the solution of a particular problem. We also describe present two pilot projects that illustrate some of the elements and issues of this scenario. The goal of this work is to make the most powerful computing systems those that are logically assembled from network based components, and to make those systems available independent of the geographic location of the constituent elements.

Loken, S.C.; Greiman, W.; Jacobson, V.L.; Johnston, W.E.; Robertson, D.W.; Tierney, B.L.

1992-09-01

355

High-performance computing and distributed systems  

SciTech Connect

We present a scenario for a fully distributed computing environment in which computing, storage, and I/O elements are configured on demand into ``virtual systems`` that are optimal for the solution of a particular problem. We also describe present two pilot projects that illustrate some of the elements and issues of this scenario. The goal of this work is to make the most powerful computing systems those that are logically assembled from network based components, and to make those systems available independent of the geographic location of the constituent elements.

Loken, S.C.; Greiman, W.; Jacobson, V.L.; Johnston, W.E.; Robertson, D.W.; Tierney, B.L.

1992-09-01

356

The message processing and distribution system development  

NASA Astrophysics Data System (ADS)

A historical approach is used in presenting the life cycle development of the Navy's message processing and distribution system beginning with the planning phase and ending with the integrated logistic support phase. Several maintenance problems which occurred after the system was accepted for fleet use were examined to determine if they resulted from errors in the acquisition process. The critical decision points of the acquisition process are examined and constructive recommendations are made for avoiding the problems which hindered the successful development of this system.

Whitten, K. L.

1981-06-01

357

Distributed parallel messaging for multiprocessor systems  

DOEpatents

A method and apparatus for distributed parallel messaging in a parallel computing system. The apparatus includes, at each node of a multiprocessor network, multiple injection messaging engine units and reception messaging engine units, each implementing a DMA engine and each supporting both multiple packet injection into and multiple reception from a network, in parallel. The reception side of the messaging unit (MU) includes a switch interface enabling writing of data of a packet received from the network to the memory system. The transmission side of the messaging unit, includes switch interface for reading from the memory system when injecting packets into the network.

Chen, Dong; Heidelberger, Philip; Salapura, Valentina; Senger, Robert M; Steinmacher-Burrow, Burhard; Sugawara, Yutaka

2013-06-04

358

Open Source Course Management Systems: A Case Study  

ERIC Educational Resources Information Center

In Fall 2003, Randolph-Macon Woman's College rolled out Claroline, an Open Source course management system for all the classes on campus. This document will cover some background on both Open Source in general and course management systems in specific, discuss technical challenges in the introduction and integration of the system and give some…

Remy, Eric

2005-01-01

359

Validation and verification in open systems architectures for RF electronics  

Microsoft Academic Search

The Integrated Sensor System (ISS) program is defining an Open Systems Architecture (OSA) for RF sensor electronics. Several previous studies have shown a significant cost-savings potential in open systems architectures based on their flexibility and ability to accommodate change. An OSA is generally considered to be a basic requirement for any new design being considered today. A number of factors

D. C. Hooks; J. Janzer

2000-01-01

360

A Cooperative Distributed Problem-Solving Management Framework for Office Automation Systems  

Microsoft Academic Search

The successful design of cost-effective development and executive environments for Office Automation (OA) depends chiefly on infor mation accessibility and flexible open system architecture A groupware management mechanism—Cooperative Distributed Problem-Solving Management Framework (CDPSMF) and its application to Office Automation System (OAS) design are given Recurrent group structure is used to characterize an enterprise or organization Management framework, using the Distributed

Feng-Chao Yang; Yu-Kuen Ho

1997-01-01

361

Splitting and paralleling research of the distribution system which contain distributed generation (DG) under the power system faults  

Microsoft Academic Search

With the using of the renewable sources increasingly, application of the distributed generation (DG) in the distribution system acquired more attention. After the power system faults, distribution system which contains many DGs would usually cut off the DGs from the distribution system at the joint where the DGs connected into the system term less. However, considering the enlarge scale and

Sun Ming; Wang Lei; Wang Zhi-Guo

2008-01-01

362

Scalable open architecture project (SOAP) avionics evolution from Federated to Open Systems  

Microsoft Academic Search

The Scalable Open Architecture Project (SOAP) of NAVAIR's Maritime Avionics Subsystems and Technologies (MAST) Program was established in 1996 to demonstrate how to evolve existing aircraft from federated to advanced scalable open systems through incremental system upgrades making maximum use of COTS technology. This project is a multiyear effort with a series of laboratory demonstrations that transform existing federated avionics

J. Ozols

1997-01-01

363

Part III: AFS - A Secure Distributed File System  

SciTech Connect

AFS is a secure distributed global file system providing location independence, scalability and transparent migration capabilities for data. AFS works across a multitude of Unix and non-Unix operating systems and is used at many large sites in production for many years. AFS still provides unique features that are not available with other distributed file systems even though AFS is almost 20 years old. This age might make it less appealing to some but with IBM making AFS available as open-source in 2000, new interest in use and development was sparked. When talking about AFS, people often mention other file systems as potential alternatives. Coda (http://www.coda.cs.cmu.edu/) with its disconnected mode will always be a research project and never have production quality. Intermezzo (http://www.inter-mezzo.org/) is now in the Linux kernel but not available for any other operating systems. NFSv4 (http://www.nfsv4.org/) which picked up many ideas from AFS and Coda is not mature enough yet to be used in serious production mode. This article presents the rich features of AFS and invites readers to play with it.

Wachsmann, A.; /SLAC

2005-06-29

364

System Engineering Strategy for Distributed Multi-Purpose Simulation Architectures  

NASA Technical Reports Server (NTRS)

This paper describes the system engineering approach used to develop distributed multi-purpose simulations. The multi-purpose simulation architecture focuses on user needs, operations, flexibility, cost and maintenance. This approach was used to develop an International Space Station (ISS) simulator, which is called the International Space Station Integrated Simulation (ISIS)1. The ISIS runs unmodified ISS flight software, system models, and the astronaut command and control interface in an open system design that allows for rapid integration of multiple ISS models. The initial intent of ISIS was to provide a distributed system that allows access to ISS flight software and models for the creation, test, and validation of crew and ground controller procedures. This capability reduces the cost and scheduling issues associated with utilizing standalone simulators in fixed locations, and facilitates discovering unknowns and errors earlier in the development lifecycle. Since its inception, the flexible architecture of the ISIS has allowed its purpose to evolve to include ground operator system and display training, flight software modification testing, and as a realistic test bed for Exploration automation technology research and development.

Bhula, Dlilpkumar; Kurt, Cindy Marie; Luty, Roger

2007-01-01

365

Open-system behavior during chondrule formation  

NASA Technical Reports Server (NTRS)

The question of whether chondrules behaved as open systems during formation is crucial to our understanding of both chondrule and chondrite formation. The very large range of chondrule types is best summarized by the compositional classification scheme, wherein the primitive chondrule groups (i.e., those not produced by metamorphic processes) are A1, A2, A5, and B1. In the Semarkona (LL3.0) chondrite, 10.5%, 25.0%, 5.0%, and 56.9% (by number) of the chondrules are groups A1, A2, A5, and B1, respectively. We argue that groups A1 and A2 were produced by reduction and evaporation during chondrule formation of material originally resembling group B1 chondrules.

Sears, D. W. G.; Shaoxiong, H.; Benoit, P. H.

1994-01-01

366

A system for distributed intrusion detection  

SciTech Connect

The study of providing security in computer networks is a rapidly growing area of interest because the network is the medium over which most attacks or intrusions on computer systems are launched. One approach to solving this problem is the intrusion-detection concept, whose basic premise is that not only abandoning the existing and huge infrastructure of possibly-insecure computer and network systems is impossible, but also replacing them by totally-secure systems may not be feasible or cost effective. Previous work on intrusion-detection systems were performed on stand-alone hosts and on a broadcast local area network (LAN) environment. The focus of our present research is to extend our network intrusion-detection concept from the LAN environment to arbitarily wider areas with the network topology being arbitrary as well. The generalized distributed environment is heterogeneous, i.e., the network nodes can be hosts or servers from different vendors, or some of them could be LAN managers, like our previous work, a network security monitor (NSM), as well. The proposed architecture for this distributed intrusion-detection system consists of the following components: a host manager in each host; a LAN manager for monitoring each LAN in the system; and a central manager which is placed at a single secure location and which receives reports from various host and LAN managers to process these reports, correlate them, and detect intrusions. 11 refs., 2 figs.

Snapp, S.R.; Brentano, J.; Dias, G.V.; Goan, T.L.; Heberlein, L.T.; Ho, Che-Lin; Levitt, K.N.; Mukherjee, B. (California Univ., Davis, CA (USA). Div. of Computer Science); Grance, T. (Air Force Cryptologic Support Center, San Antonio, TX (USA)); Mansur, D.L.; Pon, K.L. (Lawrence Livermore National Lab., CA (USA)); Smaha, S.E. (Haystack Labs., Inc., Austin, TX (USA))

1991-01-01

367

Battery Storage System sizing in distribution feeders with distributed photovoltaic systems  

Microsoft Academic Search

This paper presents a procedure for sizing a Battery Energy Storage System (BESS) for the purposed of shaving the peak demand of a residential distribution feeder. The BESS power and energy storage rating are determined from actual load demand data and desired level of peak reduction using the load following method. The impact of distributed photovoltaic (PV) power generation (to

Chandu Venu; Yann Riffonneau; Seddik Bacha; Yahia Baghzouz

2009-01-01

368

Implementation of Grid Tier 2 and Tier 3 facilities on a Distributed OpenStack Cloud  

NASA Astrophysics Data System (ADS)

The Australian Government is making a AUD 100 million investment in Compute and Storage for the academic community. The Compute facilities are provided in the form of 30,000 CPU cores located at 8 nodes around Australia in a distributed virtualized Infrastructure as a Service facility based on OpenStack. The storage will eventually consist of over 100 petabytes located at 6 nodes. All will be linked via a 100 Gb/s network. This proceeding describes the development of a fully connected WLCG Tier-2 grid site as well as a general purpose Tier-3 computing cluster based on this architecture. The facility employs an extension to Torque to enable dynamic allocations of virtual machine instances. A base Scientific Linux virtual machine (VM) image is deployed in the OpenStack cloud and automatically configured as required using Puppet. Custom scripts are used to launch multiple VMs, integrate them into the dynamic Torque cluster and to mount remote file systems. We report on our experience in developing this nation-wide ATLAS and Belle II Tier 2 and Tier 3 computing infrastructure using the national Research Cloud and storage facilities.

Limosani, Antonio; Boland, Lucien; Coddington, Paul; Crosby, Sean; Huang, Joanna; Sevior, Martin; Wilson, Ross; Zhang, Shunde

2014-06-01

369

Web services for distributed and interoperable hydro-information systems  

NASA Astrophysics Data System (ADS)

Web services support the integration and interoperability of Web-based applications and enable machine-to-machine interaction. The concepts of web services and open distributed architecture were applied to the development of T-DSS, the prototype customised for web based hydro-information systems. T-DSS provides mapping services, database related services and access to remote components, with special emphasis placed on the output flexibility (e.g. multilingualism), where SOAP web services are mainly used for communication. The remote components are represented above all by remote data and mapping services (e.g. meteorological predictions), modelling and analytical systems (currently HEC-HMS, MODFLOW and additional utilities), which support decision making in water management.

Horak, J.; Orlik, A.; Stromsky, J.

2008-03-01

370

Web services for distributed and interoperable hydro-information systems  

NASA Astrophysics Data System (ADS)

Web services support the integration and interoperability of Web-based applications and enable machine-to-machine interaction. The concepts of web services and open distributed architecture were applied to the development of T-DSS, the prototype customised for web based hydro-information systems. T-DSS provides mapping services, database related services and access to remote components, with special emphasis placed on output flexibility (e.g. multilingualism), where SOAP web services are mainly used for communication. The remote components are represented above all by distant data and mapping services (e.g. eteorological predictions), modelling and analytical systems (currently HEC-HMS, Modflow and additional utilities), which support decision making in water management.

Horak, J.; Orlik, A.; Stromsky, J.

2007-06-01

371

Derived virtual devices: a secure distributed file system mechanism  

NASA Technical Reports Server (NTRS)

This paper presents the design of derived virtual devices (DVDs). DVDs are the mechanism used by the Netstation Project to provide secure shared access to network-attached peripherals distributed in an untrusted network environment. DVDs improve Input/Output efficiency by allowing user processes to perform I/O operations directly from devices without intermediate transfer through the controlling operating system kernel. The security enforced at the device through the DVD mechanism includes resource boundary checking, user authentication, and restricted operations, e.g., read-only access. To illustrate the application of DVDs, we present the interactions between a network-attached disk and a file system designed to exploit the DVD abstraction. We further discuss third-party transfer as a mechanism intended to provide for efficient data transfer in a typical NAP environment. We show how DVDs facilitate third-party transfer, and provide the security required in a more open network environment.

VanMeter, Rodney; Hotz, Steve; Finn, Gregory

1996-01-01

372

Optimization in water distribution systems engineering  

Microsoft Academic Search

The structure and operation of water distribution systems is explained briefly, and the basic mathematical tools used to analyze\\u000a their physical behaviour are outlined. Methods for optimal planning, design and operation are presented and discussed. They\\u000a are grouped according to the engineering problem which they address and to the method of solution. This survey is given at\\u000a a level of

Uri Shamir

373

Odorant loss in natural gas distribution systems  

SciTech Connect

The loss of odorant compounds (odor fading) was studied using flow reactors which simulated the typical operating conditions of a gas distribution system. A unique method was developed to simulate rust on the inside surface of the pipeline. The study indicated that odorant loss can be impacted by the following operating parameters: Pressure; Temperature; Velocity; Iron oxide compounds; Thickness of iron oxide layer in pipe.

Moran, E.A.; Pai, P.G.; Carducci, M.I. (Lab. Services, Dept. of Engineering Activity, Michigan Consolidated Gas Co., MI (US))

1991-04-01

374

Electric power distribution and load transfer system  

SciTech Connect

This patent describes a power distribution system. It comprises at least two switch means for controlling the application of power from a power source to a power output; at least two current means for preventing reverse power flow through respective ones of switch means; and processing means for providing control signals to operate the switch means, effective to switch respective ones of the power sources between on and off states with respect to the power output.

Bradford, M.P.; Parkinson, G.W.; Grant, R.M.

1989-10-10

375

An Adaptive, Distributed Airborne Tracking System (\\  

Microsoft Academic Search

This paper describes a United States Air Force Advanced Technology Demonstration (ATD) that applied value-based scheduling to produce an adaptive, distributed tracking component appropriate for consideration by the Airborne Warning and Control System (AWACS) program. This tracker was designed to evaluate application-specific Quality of Service (QoS) metrics to quantify its ability to provide tracking services in a dynamic environment and

Raymond K. Clark; E. Douglas Jensen; Arkady Kanevsky; John A. Maurer; Paul J. Wallace; Thomas Wheeler; Yun Zhang; Douglas Wells; Tom Lawrence; Pat Hurley

1999-01-01

376

The application of Open System Architecture to planetary surface systems  

NASA Technical Reports Server (NTRS)

The issues that future planet surface activities must confront are explored, the basic concepts that provide the basis for establishing an Open System Architecture (OSA) are defined, the appropriate features of such an architecture are identified, and examples of OSAs are discussed. OSAs are designed to provide flexibility and evolutionary growth of planet surface systems to support the users needs. An OSA is based on two fundamental principles: precise definition of component functionality and the establishment of standards. An OAS must be functionally decomposed, top down, to identify all functions, subfunctions, subsubfunctions, etc., that are required to be performed by the system. There is an allocation of function, or process, to components. The functional packaging within a component becomes the user's primary perception of the system. The standards of an OSA enable the user to attain the full functional capabilities inherent in the system.

Petri, D. A.; Pieniazek, L. A.; Toups, L. D.

1992-01-01

377

A Novel Method for Optimal Distributed Generator Placement in Radial Distribution Systems  

Microsoft Academic Search

Optimal placement of distributed generators is essential, as inappropriate placement may increase the system losses. This article proposes a novel methodology for finding the optimal size and location for installation of Distributed Generators (DGs) so as to minimize total power losses in radial distribution systems. Distribution load flow is used to find the power loss in the system. The Proposed

Sri K. Nagaraju; S. Sivanagaraju; T. Ramana; S. Satyanarayana; P. V. Prasad

2011-01-01

378

Implementation of a distributed control system for electric distribution circuit reconfiguration  

Microsoft Academic Search

ENMAX Power Corporation in Calgary, Alberta, Canada is embarking on a multi-year project to improve the reliability of their electric distribution system. To this end they are deploying a distributed control system on their least reliable electric distribution circuits to automatically isolate faults and restore power to unfaulted segments. The paper describes the distributed control system, how it was integrated

Dean Craig; Craig Befus

2005-01-01

379

Jonathan: an open distributed processing environment in Java  

Microsoft Academic Search

This article describes a minimal and modular ORB framework from which it is possible to build highly flexible ORBs supporting the introduction of arbitrary binding mechanisms between interacting objects. We show that such a framework consists essentially in extending the Java notion of object reference to make it distributed. Jonathan is a Java implementation of such a framework, featuring a

Bruno Dumant; François Horn; Fr$eacute$d$eacute$ric Dang Tran; Jean-Bernard Stefani

1999-01-01

380

Electric power distribution and load transfer system  

NASA Technical Reports Server (NTRS)

A power distribution system includes a plurality of power sources and load transfer units including transistors and diodes connected in series and leading to a common power output, each of the transistors being controller switchable subject to voltage levels of the respective input and output sides of said transistors, and the voltage and current level of said common power output. The system is part of an interconnection scheme in which all but one of the power sources is connected to a single load transfer unit, enabling the survival of at least a single power source with the failure of one of the load transfer units.

Bradford, Michael P. (Inventor); Parkinson, Gerald W. (Inventor); Grant, Ross M. (Inventor)

1987-01-01

381

Electric power distribution and load transfer system  

NASA Technical Reports Server (NTRS)

A power distribution system includes a plurality of power sources and load transfer units including transistors and diodes connected in series and leading to a common power output, each of the transistors being controller switchable subject to voltage levels of the respective input and output sides of said transistors, and the voltage and current level of said common power output. The system is part of an interconnection scheme in which all but one of the power sources is connected to a single load transfer unit, enabling the survival of at least a single power source with the failure of one of the load transfer units.

Bradford, Michael P. (Inventor); Parkinson, Gerald W. (Inventor); Grant, Ross M. (Inventor)

1989-01-01

382

Petri net controllers for distributed robotic systems  

NASA Technical Reports Server (NTRS)

Petri nets are a well established modelling technique for analyzing parallel systems. When coupled with an event-driven operating system, Petri nets can provide an effective means for integrating and controlling the functions of distributed robotic applications. Recent work has shown that Petri net graphs can also serve as remarkably intuitive operator interfaces. In this paper, the advantages of using Petri nets as high-level controllers to coordinate robotic functions are outlined, the considerations for designing Petri net controllers are discussed, and simple Petri net structures for implementing an interface for operator supervision are presented. A detailed example is presented which illustrates these concepts for a sensor-based assembly application.

Lefebvre, D. R.; Saridis, George N.

1992-01-01

383

QuTiP: An open-source Python framework for the dynamics of open quantum systems  

NASA Astrophysics Data System (ADS)

We present an object-oriented open-source framework for solving the dynamics of open quantum systems written in Python. Arbitrary Hamiltonians, including time-dependent systems, may be built up from operators and states defined by a quantum object class, and then passed on to a choice of master equation or Monte Carlo solvers. We give an overview of the basic structure for the framework before detailing the numerical simulation of open system dynamics. Several examples are given to illustrate the build up to a complete calculation. Finally, we measure the performance of our library against that of current implementations. The framework described here is particularly well suited to the fields of quantum optics, superconducting circuit devices, nanomechanics, and trapped ions, while also being ideal for use in classroom instruction. Program summaryProgram title: QuTiP: The Quantum Toolbox in Python Catalogue identifier: AEMB_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEMB_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public License, version 3 No. of lines in distributed program, including test data, etc.: 16 482 No. of bytes in distributed program, including test data, etc.: 213 438 Distribution format: tar.gz Programming language: Python Computer: i386, x86-64 Operating system: Linux, Mac OSX, Windows RAM: 2+ Gigabytes Classification: 7 External routines: NumPy (http://numpy.scipy.org/), SciPy (http://www.scipy.org/), Matplotlib (http://matplotlib.sourceforge.net/) Nature of problem: Dynamics of open quantum systems. Solution method: Numerical solutions to Lindblad master equation or Monte Carlo wave function method. Restrictions: Problems must meet the criteria for using the master equation in Lindblad form. Running time: A few seconds up to several tens of minutes, depending on size of underlying Hilbert space.

Johansson, J. R.; Nation, P. D.; Nori, Franco

2012-08-01

384

Approach Light System (ALS) Multiple Distribution System Redesign.  

National Technical Information Service (NTIS)

The effort is an attempt, without sacrificing reliability, to provide a lower cost Approach Lght System (ALS) distribution system by changing from the present series output circuits to a multiple type with constant voltage and using parallel step-down tra...

R. P. Marek

1974-01-01

385

System level concurrency control for distributed database systems  

Microsoft Academic Search

A distributed database system is one in which the database is spread among several sites and application programs “move” from site to site to access and update the data they need. The concurrency control is that portion of the system that responds to the read and write requests of the application programs. Its job is to maintain the global consistency

Daniel J. Rosenkrantz; Richard Edwin Stearns; Philip M. Lewis II

1978-01-01

386

Age Dependence of the Vertical Distribution of Young Open Clusters  

NASA Astrophysics Data System (ADS)

The ages of 203 open clusters from the list of Dambis (1999) are computed in terms of Cambridge evolutionary tracks with and without the allowance for convective overshooting (Pols et al. 1998). The vertical scaleheight of the cluster layer for 123 objects at Galactocentric distances R_g = R_0 ± 1 kpc is found to vary non-monotonically with age exhibiting a wavelike pattern similar to the one earlier found for the Cepheid population (Joeveer 1974). The period of these variations is equal to PZ = 74 ± 2 Myr and PZ = 92 ± 2 Myr if cluster ages are computed in terms of evolutionary models of Pols et al. (1998) without and with overshooting, respectively. If interpreted as a manifestation of vertical virial oscillations, the implications of the pattern found are threefold: (1) the period of vertical oscillations can be reconciled with the known local density of visible matter only if cluster ages are computed with no or mild overshooting (PZ = 74 ± 2 Myr), which implies a maximum local density of ? = 0.118 ± 0.006 Modot pc^{-3} compared to ? = 0.102 Modot pc^{-3} recently inferred from Hipparcos data (Holmberg & Flynn 2000), whereas the period derived from ages computed using models with overshooting (PZ = 92 ± 2 Myr) implies a maximum local density of only ? = 0.075 ± 0.003 Modot pc^{-3} and is thus totally incompatible with recent estimates; (2) there is not much room left for the dark matter (?_DM le 0.027 Modot pc^{-3}) in the Galactic disk near the solar Galactocentric distance, and (3) at the time of their formation open clusters have, on the average, excess kinetic energy (in the vertical direction) and as a population are not in virial equilibrium; moreover, the initial vertical coordinates of open clusters (at the time of their birth) are strongly and positively correlated with initial vertical velocities (the correlation coefficient is r(Z_0,V_{Z(0)}) = 0.81 ± 0.08), thus favoring a scenario where star formation in the disk is triggered by some massive objects falling to the Galactic plane.

Dambis, A. K.

387

Automating database management for distributed database systems  

NASA Astrophysics Data System (ADS)

The management of large databases can be a time consuming and tedious task without tools to automate the process. In order to facilitata the process, a database design philosophy which is consistent with application objectives must be adopted. The Planetary Plasma Interactions (PPI) Node of the Planetary Data System (PDS) provides users with a software application which allows for rapid retrieval (for examination or extraction) of datasets which are distributed and which may exist in more than one location simultaneously. In addition, the application software, which interacts with both a local and a centralized database management system (dbms) via a client-server architecture, also is distributed. The basic problem lies in keeping all of the information current in a dynamic data environment so that the application software, regardless of its location, can access any data in the system with the greatest possible throughput. In addressing this problem the PDS/PPI Node has adopted a standardized architecture [2] and has chosen to package data management information with the data themselves as a set of detached relational flatfiles. At the PDS/PPI Node automated dbms tools are being developed which update both local and central management systems by using the information provided along with the datasets. This information can be stored in any relational database system or it can be accessed and manipulated outside of a dbms. Science data are not maintained under direct dbms control.

Joy, Steven P.; King, Todd A.; Walker, Raymond J.

1993-08-01

388

RDA integration in an open system architecture for CIM  

Microsoft Academic Search

The goal of the CIMOSA project is to provide an open system reference architecture which covers all the information needs in a manufacturing enterprise. Among all the forthcoming open systems interconnection (OSI) standards, CIMOSA has chosen the RDA (remote database access) protocol as the access protocol for the information services. The motivation of this choice, the common concepts and an

S. Messina

1993-01-01

389

Architecture of an Open Object-Oriented Database Management System  

Microsoft Academic Search

The architecture of the open object-oriented database (OODB) management system, its requirements, and its computational model, which builds database functionality as an extensible collection of transparent extensions to existing programming languages, are described. The way in which open OODB's system architecture is decomposed into a kernal meta-architecture and a collection of modules implementing specific behavioral extensions is discussed. The potential

David L. Wells; José A. Blakeley; Craig W. Thompson

1992-01-01

390

Skeletal anchorage system for open-bite correction  

Microsoft Academic Search

A skeletal anchorage system was developed for tooth movements. It consists of a titanium miniplate that is temporarily implanted in the maxilla or the mandible as an immobile anchorage. In this article, we introduce the skeletal anchorage system to intrude the lower molars in open-bite malocclusion and evaluate the results of treatment in two severe open-bite cases that underwent orthodontic

Mikako Umemori; Junji Sugawara; Hideo Mitani; Hiroshi Nagasaka; Hiroshi Kawamura

1999-01-01

391

A distributed algorithm for detecting resource deadlocks in distributed systems  

Microsoft Academic Search

This paper presents a distributed algorithm to detect deadlocks in distributed data bases. Features of this paper are (1) a formal model of the problem is presented, (2) the correctness of the algorithm is proved, i.e. we show that all true deadlocks will be detected and deadlocks will not be reported falsely, (3) no assumptions are made other than that

K. Mani Chandy; Jayadev Misra

1982-01-01

392

Extended DCA paradigm for distributed licensed open spectrum coordination  

Microsoft Academic Search

The inappropriate or under-use of spectrum offers new perspective for a secondary usage of spectrum between heterogeneous radio access technologies. This spectrum sharing can be achieved at the expense of an appropriate management of the co-channel interference between the different radio access technologies. This paper proposes an extended dynamic channel allocation (eDCA) scheme for providing distributed and real non SIR

D. Grandblaisel; K. Moessner; G. Vivier; R. Tafazolli

2005-01-01

393

On Deadlock Detection in Distributed Systems  

Microsoft Academic Search

A hierarchically organized and a distributed protocol for deadlock detection in distributed databases are presented in [1]. In this paper we show that the distributed protocol is incorrect, and present possible remedies. However, the distributed protocol remains impractical because \\

Virgil D. Gligor; Susan H. Shattuck

1980-01-01

394

Test report light duty utility arm power distribution system (PDS)  

SciTech Connect

The Light Duty Utility Arm (LDUA) Power Distribution System has completed vendor and post-delivery acceptance testing. The Power Distribution System has been found to be acceptable and is now ready for integration with the overall LDUA system.

Clark, D.A.

1996-03-04

395

Open Giant Intelligent Information Systems and Its Multiagent-Oriented System Design  

Microsoft Academic Search

Open giant intelligent information system has been studied as a new field of complex intelligent information systems. In this paper, we mainly discuss about system design of this type of complex software systems. We first introduce system complexities, and then we discusse the applicability of multiagent-based approach for building open giant intelligent information system. A multiagent system computing model based

Longbing Cao; Chunsheng Li; Chengqi Zhang; Ruwei Dai

2003-01-01

396

An open-standard smart sensor architecture and system for industrial automation  

Microsoft Academic Search

An enabling sensor technology for prognostic and health management (PHM) is the open-standard smart sensor architecture. Historically, closed or proprietary sensor buses were used to collect distributed analog sensor data to a central point for digitization. Such a system would satisfy its initial constraints, but suffer when the need for future expansion or flexibility was required. Digital sensor buses addressed

Wayne G. Baer; Richard W. Lally

2000-01-01

397

A simple algorithm for unbalanced radial distribution system load flow  

Microsoft Academic Search

Many programs of real-time applications in the area of distribution automation, such as network optimization, Var planning, switching, state estimation, and so forth, require a robust and efficient load flow method for distribution systems. Such a load flow method must be able to model the special features of distribution systems in sufficient detail. Many approaches for unbalanced radial distribution system

Sivkumar Mishra

2008-01-01

398

Standard-Cell, Open-Architecture Power Conversion Systems.  

National Technical Information Service (NTIS)

This Final Report compiles all the work carried out at the Center for Power Electronics Systems (CPES), corresponding to the 'Standard-Cell, Open- Architecture Power Conversion Systems' project sponsored by the Office of Naval Research (ONR). This project...

D. Boroyevich F. Wang F. C. Lee S. Edwards W. G. Odendaal

2005-01-01

399

Expert system prototype of food aid distribution.  

PubMed

The aim of this study was to improve efficiency of the food aid distribution process of international food relief organizations. An overall objective of this study was to develop a prototype expert system for monitoring and evaluating food aid by international disaster relief organizations. The research identifies data related to monitoring and evaluation processes of various international food-aid organizations. It then applies an artificial intelligence-based expert system to develop a prototype for those processes. Existing data related to monitoring and evaluation program cycles were obtained. An expert system shell called CLIPS(c) (National Aeronautics Space Administration) was used to develop a prototype system named Food Aid Monitor, a rule-based expert system, which uses facts and heuristic rules to provide an adaptive feedback regarding monitoring and evaluating processes at various stages of food aid operation. The Food Aid Monitor was evaluated and validated by three expert panels checking the prototype system for completeness, relevancy, consistency, correctness, precision, and use-ability. Finally, the panels indicated a belief that the system could have an overall positive impact on the stages of monitoring and evaluating food aid processes of the food relief organizations. PMID:17392088

Singh, Neeta

2007-01-01

400

Next Generation Multimedia Distributed Data Base Systems  

NASA Technical Reports Server (NTRS)

The paradigm of client/server computing is changing. The model of a server running a monolithic application and supporting clients at the desktop is giving way to a different model that blurs the line between client and server. We are on the verge of plunging into the next generation of computing technology--distributed object-oriented computing. This is not only a change in requirements but a change in opportunities, and requires a new way of thinking for Information System (IS) developers. The information system demands caused by global competition are requiring even more access to decision making tools. Simply, object-oriented technology has been developed to supersede the current design process of information systems which is not capable of handling next generation multimedia.

Pendleton, Stuart E.

1997-01-01

401

Building a generalized distributed system model  

NASA Technical Reports Server (NTRS)

The key elements in the 1992-93 period of the project are the following: (1) extensive use of the simulator to implement and test - concurrency control algorithms, interactive user interface, and replica control algorithms; and (2) investigations into the applicability of data and process replication in real-time systems. In the 1993-94 period of the project, we intend to accomplish the following: (1) concentrate on efforts to investigate the effects of data and process replication on hard and soft real-time systems - especially we will concentrate on the impact of semantic-based consistency control schemes on a distributed real-time system in terms of improved reliability, improved availability, better resource utilization, and reduced missed task deadlines; and (2) use the prototype to verify the theoretically predicted performance of locking protocols, etc.

Mukkamala, R.

1993-01-01

402

System approach to distributed sensor management  

NASA Astrophysics Data System (ADS)

Since 2003, the US Army's RDECOM CERDEC Night Vision Electronic Sensor Directorate (NVESD) has been developing a distributed Sensor Management System (SMS) that utilizes a framework which demonstrates application layer, net-centric sensor management. The core principles of the design support distributed and dynamic discovery of sensing devices and processes through a multi-layered implementation. This results in a sensor management layer that acts as a System with defined interfaces for which the characteristics, parameters, and behaviors can be described. Within the framework, the definition of a protocol is required to establish the rules for how distributed sensors should operate. The protocol defines the behaviors, capabilities, and message structures needed to operate within the functional design boundaries. The protocol definition addresses the requirements for a device (sensors or processes) to dynamically join or leave a sensor network, dynamically describe device control and data capabilities, and allow dynamic addressing of publish and subscribe functionality. The message structure is a multi-tiered definition that identifies standard, extended, and payload representations that are specifically designed to accommodate the need for standard representations of common functions, while supporting the need for feature-based functions that are typically vendor specific. The dynamic qualities of the protocol enable a User GUI application the flexibility of mapping widget-level controls to each device based on reported capabilities in real-time. The SMS approach is designed to accommodate scalability and flexibility within a defined architecture. The distributed sensor management framework and its application to a tactical sensor network will be described in this paper.

Mayott, Gregory; Miller, Gordon; Harrell, John; Hepp, Jared; Self, Mid

2010-04-01

403

Galileo spacecraft power management and distribution system  

NASA Technical Reports Server (NTRS)

The Galileo PMAD (power management and distribution system) is described, and the design drivers that established the final as-built hardware are discussed. The spacecraft is powered by two general-purpose heat-source-radioisotope thermoelectric generators. Power bus regulation is provided by a shunt regulator. Galileo PMAD distributes a 570-W beginning of mission (BOM) power source to a user complement of some 137 load elements. Extensive use of pyrotechnics requires two pyro switching subassemblies. They initiate 148 squibs which operate the 47 pyro devices on the spacecraft. Detection and correction of faults in the Galileo PMAD is an autonomous feature dictated by requirements for long life and reliability in the absence of ground-based support. Volatile computer memories in the spacecraft command and data system and attitude control system require a continuous source of backup power during all anticipated power bus fault scenarios. Power for the Jupiter Probe is conditioned, isolated, and controlled by a Probe interface subassembly. Flight performance of the spacecraft and the PMAD has been successful to date, with no major anomalies.

Detwiler, R. C.; Smith, R. L.

1990-01-01

404

Web-based distributed image processing system  

NASA Astrophysics Data System (ADS)

This paper presents a framework for developing a Web-based distributed image processing application system that is flexible, convenient, and scalable. The system uses the existing Web-based technology and image processing methodologies to implement this capability in a distributed computing environment that may include powerful machines to process complex and large images. The system consists of browser, server, service registry and task scheduler, image data storage and management, and knowledge-based image processing services. A server-side application considers the user"s request from a client side. The server host identifies the request and the necessary resources and schedules the computing resources and image processing services. Based on the instructions of the developer"s side (the service provider) a proper knowledge-based on-line assistance is given to the client to select the right algorithm, set up proper parameter values in order to maximize the usage. Developers can modify and upgrade the services at their own site and publish the workable version, its interface, and required resources to the server. The server enables remote invocation of the algorithm by providing a seamless and efficient linkage mechanism. An application for segmentation operation using deformable contour methods for complex images is provided as an example.

Han, Chia Y.; Chen, Hong; He, Lei; Wee, William G.

2003-01-01

405

Power flow study and voltage stability analysis for distribution systems with distributed generation  

Microsoft Academic Search

The voltage instability phenomena may occur in distribution networks. The decline of voltage stability level will restrict the increase of load served by distribution companies. Distributed generation (DG) is increasingly drawing great attention of people. The development of DGs will bring new chances to traditional power systems. DGs connected to distribution networks are potential to improve the system voltage stability.

Haiyan Chen; Jinfu Chen; Dongyuan Shi; Xianzhong Duan

2006-01-01

406

Distributed, cooperating knowledge-based systems  

NASA Technical Reports Server (NTRS)

Some current research in the development and application of distributed, cooperating knowledge-based systems technology is addressed. The focus of the current research is the spacecraft ground operations environment. The underlying hypothesis is that, because of the increasing size, complexity, and cost of planned systems, conventional procedural approaches to the architecture of automated systems will give way to a more comprehensive knowledge-based approach. A hallmark of these future systems will be the integration of multiple knowledge-based agents which understand the operational goals of the system and cooperate with each other and the humans in the loop to attain the goals. The current work includes the development of a reference model for knowledge-base management, the development of a formal model of cooperating knowledge-based agents, the use of testbed for prototyping and evaluating various knowledge-based concepts, and beginning work on the establishment of an object-oriented model of an intelligent end-to-end (spacecraft to user) system. An introductory discussion of these activities is presented, the major concepts and principles being investigated are highlighted, and their potential use in other application domains is indicated.

Truszkowski, Walt

1991-01-01

407

Toward Data Confidentiality via Integrating Hybrid Encryption Schemes and Hadoop Distributed File System  

Microsoft Academic Search

With the increasing popularity of cloud computing, Hadoop has become a widely used open source cloud computing framework for large scale data processing. However, few studies have been done to enhance data confidentiality of Hadoop against storage servers. In this paper, we address the data confidentiality issue by integrating hybrid encryption schemes and the Hadoop distributed file system (HDFS). We

Hsiao-Ying Lin; Shiuan-Tzuo Shen; Wen-Guey Tzeng; Bao-Shuh P. Lin

2012-01-01

408

Modeling and Managing State in Distributed Systems: The Role of OGSI and WSRF  

Microsoft Academic Search

We often encounter in distributed systems the need to model, access, and manage state. This state may be, for example, data in a purchase order, service level agreements representing resource availability, or the current load on a computer. We introduce two closely related approaches to modeling and manipulating state within a Web services (WS) framework: the Open Grid Services Infrastructure

IAN FOSTER; KARL CZAJKOWSKI; DONALD F. FERGUSON; JEFFREY FREY; STEVE GRAHAM; TOM MAGUIRE; DAVID SNELLING; STEVEN TUECKE

2005-01-01

409

A fuzzy genetic approach for network reconfiguration to enhance voltage stability in radial distribution systems  

Microsoft Academic Search

This paper presents a fuzzy genetic approach for reconfiguration of radial distribution systems (RDS) so as to maximize the voltage stability of the network for a specific set of loads. The network reconfiguration involves a mechanism for selection of the best set of branches to be opened, one from each loop, such that the reconfigured RDS possesses desired performance characteristics.

N. C. Sahoo; K. Prasad

2006-01-01

410

A Cooperative Simulation Mechanism of Distributed Control Systems Based on Object-Oriented Design Pattern  

Microsoft Academic Search

Distributed control systems (DCSs) consisting of a plant, a controller composed of many devices, and an open network interconnecting devices, are now used in many automation areas. For assuring the control performance under the heavy traffic on the network, the simulation of DCS is strongly needed. In the case of DCSs for controlling a mechanical plant, the graphical and cooperative

Toyoaki Tomura; Satoshi Kanai; Takeshi Kishinami

2003-01-01

411

Two analytical approaches for optimal placement of distributed generation unit in power systems  

Microsoft Academic Search

With ever-increasing demand of electricity consumption and increasing open access particularly in restructured environment, transmission line congestion is quite frequent. For alleviating congestion, proper locations of DG are important. This paper focuses a comparative study between a novel bus reduction approach and modified load flow with optimization for determination of the optimal placement of single distributed generator in power systems.

Sudipta Ghosh; S. P. Ghoshal

2009-01-01

412

Hot Water Distribution System Model Enhancements  

SciTech Connect

This project involves enhancement of the HWSIM distribution system model to more accurately model pipe heat transfer. Recent laboratory testing efforts have indicated that the modeling of radiant heat transfer effects is needed to accurately characterize piping heat loss. An analytical methodology for integrating radiant heat transfer was implemented with HWSIM. Laboratory test data collected in another project was then used to validate the model for a variety of uninsulated and insulated pipe cases (copper, PEX, and CPVC). Results appear favorable, with typical deviations from lab results less than 8%.

Hoeschele, M.; Weitzel, E.

2012-11-01

413

Open-ended magnetic confinement systems for fusion  

SciTech Connect

Magnetic confinement systems that use externally generated magnetic fields can be divided topologically into two classes: ``closed`` and `open``. The tokamak, the stellarator, and the reversed-field-pinch approaches are representatives of the first category, while mirror-based systems and their variants are of the second category. While the recent thrust of magnetic fusion research, with its emphasis on the tokamak, has been concentrated on closed geometry, there are significant reasons for the continued pursuit of research into open-ended systems. The paper discusses these reasons, reviews the history and the present status of open-ended systems, and suggests some future directions for the research.

Post, R.F.; Ryutov, D.D.

1995-05-01

414

Comprehensive Large Array-data Stewardship System (CLASS)A Fully-distributed System  

NASA Astrophysics Data System (ADS)

The Comprehensive Large Array-data Stewardship System (CLASS) is moving from its dual site operation to a multi-node, distributed architecture. The next step in this process is to move to a three-node architecture in North Carolina, Colorado, and West Virginia. Subsequently, CLASS will transition to a fully-distributed system by migrating to a highly structured, layered (distributed) architecture. While so-called "service-oriented" architectures often describe numerous layers, CLASS refers to two primary layers: infrastructure and application. An infrastructure layer is needed to provide common capabilities for distributed application development and deployment. Applications interact with the infrastructure layer though stable, published interfaces. The infrastructure layer abstracts the complexities of distributed computing such that developers, system administrators, operators, and others can focus on CLASS application logic rather than the mechanisms which support it. The application layer will use artifacts to implement CLASS-specific capabilities or services. Ingest, dissemination, search, and order are a few among many examples. Application layer components utilize services from the infrastructure to provide distributed behavior, and to simplify and streamline application development, deployment, and operations processes. As CLASS evolves to become a fully-distributed system, each transitional phase supports the need for CLASS's architecture to provide a context of reliability, performance, and extensibility. Moreover, these important qualities must be achieved in a constantly and quickly changing environment, emphasizing the need for CLASS to be easily adaptable in its pursuit of these goals. Transitioning to a distributed, open, heterogeneous environment with a powerful and stable infrastructure and fine-grained, decoupled applications will make it possible for CLASS to achieve these objectives economically and rapidly.

Rank, R.; Reynolds, R. G.

2005-12-01

415

Refrigerant Leakage Detection and Diagnosis for a Distributed Refrigeration System  

Microsoft Academic Search

A new technique to detect and diagnose leakage in a distributed refrigeration system is proposed in this paper. Unlike a simple refrigeration system of an HVAC system, a distributed refrigeration system, such as the refrigeration system in a supermarket, consists of several racks of compressors and evaporators, large condenser systems on the roof, meters of refrigerant piping systems, and liquid

Kriengkrai Assawamartbunlue; Michael J. Brandemuehl

2006-01-01

416

Open cycle lithium chloride cooling system  

NASA Astrophysics Data System (ADS)

A lithium chloride open cycle absorption chiller has been designed, built and tested. Solution reconcentration takes place in a small counter current packed column supplied with solar heated air. Removal of noncondensable gases that enter the chiller dissolved in the strong solution and the make-up refrigerant streams is accomplished by a liquid-jet ejector and a small vacuum pump. Cooling capacities approaching 1.4 tons and COP levels of 0.58 have been achieved at non-optimum operating conditions. Test results from preliminary system operation suggest that mass transfer processes in both the packed column reconcentrator and the absorber are controlled by concentration gradients in the lithium chloride solution. Liquid phase controlled mass transfer dictates an operating strategy different from the previously assumed gas phase controlled process to obtain maximum rates of evaporation in the packed column. Determination of optimal operating conditions leading to decreased electrical power consumption and improved cooling capacity and coefficient of performance will require further analysis and testing.

Lenz, T. G.; Loef, G. O. G.; Iyer, R.; Wenger, J.

1983-05-01

417

Differential Distributions of Synechococcus Subgroups Across the California Current System  

PubMed Central

Synechococcus is an abundant marine cyanobacterial genus composed of different populations that vary physiologically. Synechococcus narB gene sequences (encoding for nitrate reductase in cyanobacteria) obtained previously from isolates and the environment (e.g., North Pacific Gyre Station ALOHA, Hawaii or Monterey Bay, CA, USA) were used to develop quantitative PCR (qPCR) assays. These qPCR assays were used to quantify populations from specific narB phylogenetic clades across the California Current System (CCS), a region composed of dynamic zones between a coastal-upwelling zone and the oligotrophic Pacific Ocean. Targeted populations (narB subgroups) had different biogeographic patterns across the CCS, which appear to be driven by environmental conditions. Subgroups C_C1, D_C1, and D_C2 were abundant in coastal-upwelling to coastal-transition zone waters with relatively high to intermediate ammonium, nitrate, and chl. a concentrations. Subgroups A_C1 and F_C1 were most abundant in coastal-transition zone waters with intermediate nutrient concentrations. E_O1 and G_O1 were most abundant at different depths of oligotrophic open-ocean waters (either in the upper mixed layer or just below). E_O1, A_C1, and F_C1 distributions differed from other narB subgroups and likely possess unique ecologies enabling them to be most abundant in waters between coastal and open-ocean waters. Different CCS zones possessed distinct Synechococcus communities. Core California current water possessed low numbers of narB subgroups relative to counted Synechococcus cells, and coastal-transition waters contained high abundances of Synechococcus cells and total number of narB subgroups. The presented biogeographic data provides insight on the distributions and ecologies of Synechococcus present in an eastern boundary current system.

Paerl, Ryan W.; Johnson, Kenneth S.; Welsh, Rory M.; Worden, Alexandra Z.; Chavez, Francisco P.; Zehr, Jonathan P.

2011-01-01

418

Photoelectron Angular Distributions of s Electrons in Open-Shell Atoms  

Microsoft Academic Search

It is shown that the photoelectron angular distribution of s electrons in an open-shell atom, having outer configuration ns2npq, is not described by the asymmetry parameter beta=2, as predicted by more approximate theories, but has dramatic variations with energy even within LS coupling. Calculations for the 3s subshell in Cl are presented as an example.

Anthony F. Starace; Robert H. Rast; Steven T. Manson

1977-01-01

419

Photoelectron angular distributions of s electrons in open-shell atoms  

Microsoft Academic Search

It is shown that the photoelectron angular distribution of s electrons in an open-shell atom, having outer configuration ns²np\\/sup q\\/, is not described by the asymmetry parameter ..beta.. = 2, as predicted by more approximate theories, but has dramatic variations with energy even within LS coupling. Calculations for the 3s subshell in Cl are presented as an example.

Anthony Starace; Robert Rast; Steven Manson

1977-01-01

420

Managing the Complexity of Large Free and Open Source Package-Based Software Distributions  

Microsoft Academic Search

The widespread adoption of Free and Open Source Soft- ware (FOSS) in many strategic contexts of the information technology society has drawn the attention on the issues re- garding how to handle the complexity of assembling and managing a huge number of (packaged) components in a consistent and effective way. FOSS distributions (and in particular GNU\\/Linux-based ones) have always provided

Fabio Mancinelli; Jaap Boender; Roberto Di Cosmo; Jerome Vouillon; Berke Durak; Xavier Leroy; Ralf Treinen

2006-01-01

421

The Production and Distribution of Knowledge through Open and Distance Learning  

Microsoft Academic Search

Open and distance learning (ODL) technology offers a new form of market mechanism for the distribution of knowledge which is increasingly presented as a commodity like any other. Information technology (IT) is also having an impact on the technical and social production of knowledge and higher learning in general. This paper will explore a range of issues arising from this

Stephen Fox

1989-01-01

422

Broadcasting Systems: An Advanced CATV System with Wireless Distribution  

NASA Astrophysics Data System (ADS)

CATV(Community Antenna TV) has been started as a measure intended to improve the poor reception area since 1955 at the spa of lkaho in Gunma prefecture. Recently CATV has come into the limelight as a multi program distributor and a new transmission media of the broadband Internet. The percentage of household CATV sets is 22% in 2000 in Japan. The wireless distributed CATV system is able to complement the wired system. It is serviceable in where the cable cannot lay, such as the area studded with houses or isolated island. In this paper, an advanced CATV system with wireless distribution is mentioned. The frequency band is the millimeter-wave band, because it has the characteristic of allowing broadband transmission and miniaturization of devices. The link budget of the test system using 60-GHz band is also described.

Tsuzuku, Aiichiro

2001-12-01

423

Distributed health care imaging information systems  

NASA Astrophysics Data System (ADS)

We have developed an ATM network-based system to collect and catalogue cardio-angiogram videos from the source at a Kaiser central facility and make them available for viewing by doctors at primary care Kaiser facilities. This an example of the general problem of diagnostic data being generated at tertiary facilities, while the images, or other large data objects they produce, need to be used from a variety of other locations such as doctor's offices or local hospitals. We describe the use of a highly distributed computing and storage architecture to provide all aspects of collecting, storing, analyzing, and accessing such large data-objects in a metropolitan area ATM network. Our large data-object management system provides network interface between the object sources, the data management system and the user of the data. As the data is being stored, a cataloguing system automatically creates and stores condensed versions of the data, textural metadata and pointers to the original data. The catalogue system provides a Web-based graphical interface to the data. The user is able the view the low-resolution data with a standard Internet connection and Web browser. If high-resolution is required, a high-speed connection and special application programs can be used to view the high-resolution original data.

Thompson, Mary R.; Johnston, William E.; Guojun, Jin; Lee, Jason; Tierney, Brian; Terdiman, Joseph F.

1997-05-01

424

Distributed intelligence for ground/space systems  

NASA Technical Reports Server (NTRS)

DI is short for Distributed Intelligence for Ground/Space Systems and the DI Study is one in a series of ESA projects concerned with the development of new concepts and architectures for future autonomous spacecraft systems. The kick-off of DI was in January 1994 and the planned duration is three years. The background of DI is the desire to design future ground/space systems with a higher degree of autonomy than seen in today's missions. The aim of introducing autonomy in spacecraft systems is to: (1) lift the role of the spacecraft operators from routine work and basic troubleshooting to supervision; (2) ease access to and increase availability of spacecraft resources; (3) carry out basic mission planning for users; (4) enable missions which have not yet been feasible due to eg. propagation delays, insufficient ground station coverage etc.; and (5) possibly reduce mission cost. The study serves to identify the feasibility of using state-of-the-art technologies in the area of planning, scheduling, fault detection using model-based diagnosis and knowledge processing to obtain a higher level of autonomy in ground/space systems.

Aarup, Mads; Munch, Klaus Heje; Fuchs, Joachim; Hartmann, Ralf; Baud, Tim

1994-01-01

425

Remote procedure execution software for distributed systems  

SciTech Connect

Remote Procedure Execution facilitates the construction of distributed software systems, spanning computers of various types. Programmers who use the RPX package specify subroutine calls which are to be executed on a remote computer. RPX is used to generate code for dummy routines which transmit input parameters and receive output parameters, as well as a main program which receives procedure call requests, calls the requested procedure, and returns the result. The package automatically performs datatype conversions and uses an appropriate connection oriented protocol. Supported operating systems/processors are VMS(VAX), UNIX(MIPS R2000, R3000) and Software Components Group's pSOS (680x0). Connection oriented protocols are supported over Ethernet (TCP/IP) and RS232 (a package of our own design). 2 refs., 2 figs.

Petravick, D.L.; Berman, E.F.; Sergey, G.P.

1989-05-01

426

Distributed fiber optic moisture intrusion sensing system  

DOEpatents

Method and system for monitoring and identifying moisture intrusion in soil such as is contained in landfills housing radioactive and/or hazardous waste. The invention utilizes the principle that moist or wet soil has a higher thermal conductance than dry soil. The invention employs optical time delay reflectometry in connection with a distributed temperature sensing system together with heating means in order to identify discrete areas within a volume of soil wherein temperature is lower. According to the invention an optical element and, optionally, a heating element may be included in a cable or other similar structure and arranged in a serpentine fashion within a volume of soil to achieve efficient temperature detection across a large area or three dimensional volume of soil. Remediation, moisture countermeasures, or other responsive action may then be coordinated based on the assumption that cooler regions within a soil volume may signal moisture intrusion where those regions are located.

Weiss, Jonathan D. (Albuquerque, NM)

2003-06-24

427

Distributed control system for turbine engines  

SciTech Connect

A distributed control system (DCS) for a turbine engine has been demonstrated and tested, consisting of prototype electronic interface units (EIUs) connected to data and power busses. In the DCS, a central control computer communicated with smart sensors and smart actuators via a 2.5 megabit/sec digital data bus, using the Fieldbus protocol. Power was distributed to the smart devices as 100 kHz 100V peak AC, allowing light, simple power converters at each smart device. All smart sensors, smart actuators, and cables were dual redundant. The smart actuators received position demand from the central control computer, exchanged data between channels to provide local redundancy management, closed the position loop locally, and reported actuator position to the central controller. Smart sensors converted sensed signals to digital values in engineering units, and performed local built-in tests. Testing of the DCS was done in a closed-loop simulation with an engine model. Frequency response of the DCS was almost identical with the conventional system.

Shaffer, P.L. [General Electric Aircraft Engines, Cincinnati, OH (United States)

1999-01-01

428

Adaptive load sharing in heterogeneous distributed systems  

NASA Astrophysics Data System (ADS)

In this paper, we study the performance characteristics of simple load sharing algorithms for heterogeneous distributed systems. We assume that nonnegligible delays are encountered in transferring jobs from one node to another. We analyze the effects of these delays on the performance of two threshold-based algorithms called Forward and Reverse. We formulate queuing theoretic models for each of the algorithms operating in heterogeneous systems under the assumption that the job arrival process at each node in Poisson and the service times and job transfer times are exponentially distributed. The models are solved using the Matrix-Geometric solution technique. These models are used to study the effects of different parameters and algorithm variations on the mean job response time: e.g., the effects of varying the thresholds, the impact of changing the probe limit, the impact of biasing the probing, and the optimal response times over a large range of loads and delays. Wherever relevant, the results of the models are compared with the M/M/ 1 model, representing no load balancing (hereafter referred to as NLB), and the M/M/K model, which is an achievable lower bound (hereafter referred to as LB).

Mirchandaney, Ravi; Towsley, Don; Stankovic, John A.

1990-08-01

429

Impact of Distributed Generators on Protective Devices in Radial Distribution Systems  

Microsoft Academic Search

Proper protection of distribution systems is essential to ensure high reliability and power quality. With the proposed migration to the inclusion of distributed generation in distribution systems, it is critical that the protection schemes be adapted to address these new and very different system characteristics. The authors of this paper have studied the impact of the integration of DGs in

Karen L. Butler-Purry; Matthew Marotti

2006-01-01

430

A New Power Flow Method in Radial Distribution Systems  

Microsoft Academic Search

In this paper, a new efficient method is proposed for power flow calculation in radial distribution systems. The distribution busines is changing the need to plan and respond to technical change, growth in distributed generation and deregulated power markets. Thus, it is important to improve fundamental analytical tools in distribution systems. This paper proposes a new method for the power

Wataru Ohyoshi; Hiroyuki Mori

2006-01-01

431

Competition and Cooperation of Distributed Generation and Power System  

Microsoft Academic Search

Advances in distributed generation technologies together with the deregulation of an electric power industry can lead to a massive introduction of distributed generation. Since most of distributed generation will be interconnected to a power system, coordination and competition between distributed generators and large-scale power sources would be a vital issue in realizing a more desirable energy system in the future.

Masatoshi Miyake; Toshiya Nanahara

2005-01-01

432

Distributed generation power system modeling in nonlinear Hamiltonian form  

Microsoft Academic Search

Distributed generation has dramatically changed the structure of modern power systems. In this structure, power electronic devices are extensively used providing the possibility of new control strategies in the distribution network. To implement these strategies, a complete dynamic analysis of the distributed generation system is needed. In this paper, exploiting a common feature of almost all the distributed generation components

Konstantinos F. Krommydas; George C. Konstantopoulos; Michael K. Bourdoulis; Antonio T. Alexandridis

2012-01-01

433

Open Source Library Management Systems: A Multidimensional Evaluation  

ERIC Educational Resources Information Center

Open source library management systems have improved steadily in the last five years. They now present a credible option for small to medium libraries and library networks. An approach to their evaluation is proposed that takes account of three additional dimensions that only open source can offer: the developer and support community, the source…

Balnaves, Edmund

2008-01-01

434

An Open Source Environment for Cell Broadband Engine System Software  

Microsoft Academic Search

The cell broadband engine provides the first implementation of a chip multiprocessor with a significant number of general-purpose programmable cores targeting a broad set of workloads. Open source software played a critical role in the development of the cell software stack. The system includes a power architecture processor and eight attached processor element. The cell team turned to open source

Michael Gschwind; David Erb; Sid Manning; Mark Nutter

2007-01-01

435

Wireless measurement system for extracting open loop micro coils paramters  

Microsoft Academic Search

We report for the first time wireless extraction of open ended micro coil inductance L, parasitic capacitance C and resistance R using an inductively coupled passive system which consists of an electrically small magnetic loop antenna as a sensor coil and an open ended test micro coil. Wireless analytical model is developed which includes the gimmick effects generated due to

Adnan Yousaf; Thomas Jeager; L. Reindl

2011-01-01

436

SOFC combined cycle systems for distributed generation  

SciTech Connect

The final phase of the tubular SOFC development program will focus on the development and demonstration of pressurized solid oxide fuel cell (PSOFC)/gas turbine (GT) combined cycle power systems for distributed power applications. The commercial PSOFC/GT product line will cover the power range 200 kWe to 50 MWe, and the electrical efficiency for these systems will range from 60 to 75% (net AC/LHV CH4), the highest of any known fossil fueled power generation technology. The first demonstration of a pressurized solid oxide fuel cell/gas turbine combined cycle will be a proof-of-concept 250 kWe PSOFC/MTG power system consisting of a single 200 kWe PSOFC module and a 50 kWe microturbine generator (MTG). The second demonstration of this combined cycle will be 1.3 MWe fully packaged, commercial prototype PSOFC/GT power system consisting of two 500 kWe PSOFC modules and a 300 kWe gas turbine.

Brown, R.A.

1997-05-01

437

Safety and Reliability Driven Task Allocation in Distributed Systems  

Microsoft Academic Search

Distributed computer systems are increasingly being employed for critical applications, such as aircraft control, industrial process control, and banking systems. Maximizing performance has been the conventional objective in the allocation of tasks for such systems. Inherently, distributed systems are more complex than centralized systems. The added complexity could increase the potential for system failures. Some work has been done in

S. Srinivasan; Niraj K. Jha

1999-01-01

438

Distributions of dissolved vitamin B 12 and Co in coastal and open-ocean environments  

NASA Astrophysics Data System (ADS)

Distributions of dissolved vitamin B 12 and total dissolved Co were measured to gain an understanding of the cycling of these interdependent micronutrients in six marine settings including; an upwelling location, a semi-enclosed bay, two urban coastal systems, and two open ocean locations. Along the coast of Baja California, Mexico, concentrations of B 12 and dissolved Co varied from 0.2 to 11 pM and 180 to 990 pM, respectively. At a nearby upwelling station, vitamin B 12 and Co concentrations ranged from 0.3 to 7.0 pM and 22 to 145 pM, and concentrations did not correlate with upwelling intensity. Concentrations of B 12 were highest within Todos Santos Bay, a semi-enclosed bay off the coast of Baja California, Mexico, during a dinoflagellate bloom, ranging from 2 to 61 pM, while Co concentrations varied between 61 and 194 pM. In the anthropogenically impacted Long Island Sound, NY, U.S.A., B 12 levels were between 0.1 and 23 pM and Co concentrations varied from 60 to 1900 pM. However, anthropogenic inputs were not evident in B 12 levels in the San Pedro Basin, located outside Los Angeles, Ca, U.S.A., where concentrations of B 12 were 0.2-1.8 pM, approximating observed open ocean B 12 concentrations. In the Southern Ocean and North Atlantic Ocean, B 12 levels were 0.4-4 pM and 0.2-2 pM, respectively. Total Co concentrations in the Southern Ocean and North Atlantic tended to be low; measuring 26-59 pM and 15-80 pM, respectively. These low Co concentrations may limit B 12 synthesis and its availability to B 12-requiring phytoplankton because the total dissolved Co pool is not necessarily entirely bioavailable.

Panzeca, Caterina; Beck, Aaron J.; Tovar-Sanchez, Antonio; Segovia-Zavala, Jose; Taylor, Gordon T.; Gobler, Christopher J.; Sañudo-Wilhelmy, Sergio A.

2009-11-01

439

Redundant Ring Structures for Shipboard Distributed Computer Systems.  

National Technical Information Service (NTIS)

The potential constraints on a ring structured distributed computing system imposed by the shipboard environment were discussed. The feasibility of increasing distributed ring system availability to meet the requirements were investigated. It was shown th...

P. B. Snyder

1976-01-01

440

Assessment of Distributed Photovoltaic Electric-Power Systems. Final Report.  

National Technical Information Service (NTIS)

The purpose of this study was to develop a methodology for assessing the potential impacts of distributed photovoltaic (PV) systems on electric utility systems, including subtransmission and distribution networks, and to apply that methodology to several ...

R. W. Neal P. F. DeDuck R. N. Marshall

1982-01-01

441

49 CFR 192.747 - Valve maintenance: Distribution systems.  

Code of Federal Regulations, 2013 CFR

... 2013-10-01 2013-10-01 false Valve maintenance: Distribution systems. 192...SAFETY STANDARDS Maintenance § 192.747 Valve maintenance: Distribution systems. (a) Each valve, the use of which may be necessary...

2013-10-01

442

46 CFR 28.855 - Electrical distribution systems.  

Code of Federal Regulations, 2013 CFR

...COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS REQUIREMENTS FOR COMMERCIAL FISHING INDUSTRY VESSELS Aleutian Trade Act Vessels § 28.855 Electrical distribution systems. (a) Each electrical distribution system which...

2013-10-01

443

Layering Central Authentication on Existing Distributed System Interactive Services.  

National Technical Information Service (NTIS)

Provision of interactive terminal service in a distributed system requires mechanisms to logon and logoff as well as to move textual data between the terminal host and remote host. Logon occurs in most distributed systems subsequent to the establishment o...

D. M. Nessett

1987-01-01

444

Open cycle ocean thermal energy conversion system  

DOEpatents

An improved open cycle ocean thermal energy conversion system including a flash evaporator for vaporizing relatively warm ocean surface water and an axial flow, elastic fluid turbine having a vertical shaft and axis of rotation. The warm ocean water is transmitted to the evaporator through a first prestressed concrete skirt-conduit structure circumferentially situated about the axis of rotation. The unflashed warm ocean water exits the evaporator through a second prestressed concrete skirt-conduit structure located circumferentially about and radially within the first skirt-conduit structure. The radially inner surface of the second skirt conduit structure constitutes a cylinder which functions as the turbine's outer casing and obviates the need for a conventional outer housing. The turbine includes a radially enlarged disc element attached to the shaft for supporting at least one axial row of radially directed blades through which the steam is expanded. A prestressed concrete inner casing structure of the turbine has upstream and downstream portions respectively situated upstream and downstream from the disc element. The radially outer surfaces of the inner casing portions and radially outer periphery of the axially interposed disc cooperatively form a downwardly radially inwardly tapered surface. An annular steam flowpath of increasing flow area in the downward axial direction is radially bounded by the inner and outer prestressed concrete casing structures. The inner casing portions each include a transversely situated prestressed concrete circular wall for rotatably supporting the turbine shaft and associated structure. The turbine blades are substantially radially coextensive with the steam flowpath and receive steam from the evaporator through an annular array of prestressed concrete stationary vanes which extend between the inner and outer casings to provide structural support therefor and impart a desired flow direction to the steam.

Wittig, J. Michael (West Goshen, PA)

1980-01-01

445

Multiple weapon system distributed sensor concept  

NASA Astrophysics Data System (ADS)

Distributed Sensor Concept-DISCO was proposed for multiplication of individual weapon capability through cooperative target engagement. DISCO creates practically distributed in space sensor network that performs sensing by exchanging of pre-track frame and GNC data. Concept of operations for DISCO is based on complete absence of any kind of host vehicle with its weight allocated for unique and costly propulsion, communication and avionics, and, in the same time DISCO preserves the original idea of multiplicity of lightweight effective weapon dispensed from an unitary payload Three major benefits of DISCO are: immediate PBO deployment; absence of any kind of carrier or "central" vehicle or bus; multiplicity of weapon. DISCO sensor network supports target handover without active ranging but by triangulating. Digital video-signal processing that supports DISCO is Recursive Adaptive Frame Integration of Limited data. Each sensor disseminates to and receives frame, calibration and GNC data from other sensors in the network. In this paper efficiency of DISCO weapon system is discussed for acquisition, accurate handover and track correlation.

Rafailov, Michael K.

2009-05-01

446

Clock distribution system for digital computers  

DOEpatents

Apparatus for eliminating, in each clock distribution amplifier of a clock distribution system, sequential pulse catch-up error due to one pulse "overtaking" a prior clock pulse. The apparatus includes timing means to produce a periodic electromagnetic signal with a fundamental frequency having a fundamental frequency component V'.sub.01 (t); an array of N signal characteristic detector means, with detector means No. 1 receiving the timing means signal and producing a change-of-state signal V.sub.1 (t) in response to receipt of a signal above a predetermined threshold; N substantially identical filter means, one filter means being operatively associated with each detector means, for receiving the change-of-state signal V.sub.n (t) and producing a modified change-of-state signal V'.sub.n (t) (n=1, . . . , N) having a fundamental frequency component that is substantially proportional to V'.sub.01 (t-.theta..sub.n (t) with a cumulative phase shift .theta..sub.n (t) having a time derivative that may be made uniformly and arbitrarily small; and with the detector means n+1 (1.ltoreq.n

Wyman, Robert H. (Brentwood, CA); Loomis, Jr., Herschel H. (Davis, CA)

1981-01-01

447

Dynamic Change Management by Distributed Graph Transformation: Towards Configurable Distributed Systems  

Microsoft Academic Search

\\u000a In this contribution we consider the application of distributed graph transformation to the problem of specifying dynamic\\u000a change in distributed systems. Change in distributed systems is related to at least two levels. One is the management of change\\u000a in a local node of the distributed system and how such a local change is then propagated to those nodes which need

Gabriele Taentzer; Michael Goedicke; Torsten Meyer

1998-01-01

448

The Unidata LDM Data Distribution System  

NASA Astrophysics Data System (ADS)

The Unidata LDM is a near real-time, event-driven system for transmitting frequently-generated data-products, 24/7, from a producer to multiple subscribers using the Internet. Once received, a data-product is processed according to user specifications. A data-product can be anything up to 4 gigabytes in size. Downstream LDM-s register a regular expression based selection predicate with upstream LDM-s. Network topologies include point-to-point, star, and tree. Based on ONC RPC, the LDM system is extremely robust and efficient. Since its initial release in 1994, a network of LDM-s called the Internet Data Distribution (IDD) system has been the primary means by which many if not most Earth Sciences departments in the US obtain and process meteorological data (up to 20 GB/hour and 250k products/hour) with latencies measured in seconds or less. Data-products include numerical model output, radar data, WMO bulletins, and lightning data. Users of the LDM also include the international atmospheric science university community, NOAA, NASA, USGS, the US military, ECMWF, and the meteorological agencies of China, Australia, Brazil, South Korea, and Vietnam. The LDM is the highest volume advanced application on Internet-2 (currently averaging 27 terabytes per week). The LDM history and architecture is presented together with an analysis of its strengths and weaknesses.

Emmerson, S.; Yoksas, T. C.; Weber, W. J.; Schmidt, M.

2010-12-01

449

Integrating biological data - the Distributed Annotation System  

PubMed Central

Background The Distributed Annotation System (DAS) is a widely adopted protocol for dynamically integrating a wide range of biological data from geographically diverse sources. DAS continues to expand its applicability and evolve in response to new challenges facing integrative bioinformatics. Results Here we describe the various infrastructure components of DAS and present a new extended version of the DAS specification. Version 1.53E incorporates several recent developments, including its extension to serve new data types and an ontology for protein features. Conclusion Our extensions to the DAS protocol have facilitated the integration of new data types, and our improvements to the existing DAS infrastructure have addressed recent challenges. The steadily increasing numbers of available data sources demonstrates further adoption of the DAS protocol.

Jenkinson, Andrew M; Albrecht, Mario; Birney, Ewan; Blankenburg, Hagen; Down, Thomas; Finn, Robert D; Hermjakob, Henning; Hubbard, Tim JP; Jimenez, Rafael C; Jones, Philip; Kahari, Andreas; Kulesha, Eugene; Macias, Jose R; Reeves, Gabrielle A; Prlic, Andreas

2008-01-01

450

A radial distribution function-based open boundary force model for multi-centered molecules  

NASA Astrophysics Data System (ADS)

We derive an expression for radial distribution function (RDF)-based open boundary forcing for molecules with multiple interaction sites. Due to the high-dimensionality of the molecule configuration space and missing rotational invariance, a computationally cheap, 1D approximation of the arising integral expressions as in the single-centered case is not possible anymore. We propose a simple, yet accurate model invoking standard molecule- and site-based RDFs to approximate the respective integral equation. The new open boundary force model is validated for ethane in different scenarios and shows very good agreement with data from periodic simulations.

Neumann, Philipp; Eckhardt, Wolfgang; Bungartz, Hans-Joachim

2014-12-01

451

Fractional System Identification: An Approach Using Continuous Order-Distributions  

NASA Technical Reports Server (NTRS)

This paper discusses the identification of fractional- and integer-order systems using the concept of continuous order-distribution. Based on the ability to define systems using continuous order-distributions, it is shown that frequency domain system identification can be performed using least squares techniques after discretizing the order-distribution.

Hartley, Tom T.; Lorenzo, Carl F.

1999-01-01

452

Distribution System Analysis to support the Smart Grid  

Microsoft Academic Search

The “Smart Grid” refers to various efforts to modernize the power grid through the application of intelligent devices. This paper describes current thinking by members of the Distribution System Analysis Subcommittee (DSA SC) on how distribution system analysis might evolve to support the Smart Grid. Various issues related to Smart Grid and distribution system analysis are identified. The essential characteristics

R. C. Dugan; R. F. Arritt; T. E. McDermott; S. M. Brahma; K. Schneider

2010-01-01

453

Predicting the Formation of DBPs by the Simulated Distribution System  

Microsoft Academic Search

A simulated distribution system (SDS) method has been developed to predict the amounts of disinfection by-products (DBPs) that would form in a distribution system. The parameters (chlorine dosage, incubation temperature, and incubation holding time) of the method are chosen to simulate the conditions of the treatment plant and the distribution system. A study was conducted on the Metropolitan Water District

Bart Koch; Stuart W. Krasner; Michael J. Sclimenti; Warren K. Schimpff

1991-01-01

454

Design and realization of GIS based urban logistics distribution system  

Microsoft Academic Search

On the basis of analyzing the logistics distribution principles systematically and the application of GIS in logistics industry, from the angle of the integration of urban GIS system and logistics distribution, the article adopts C#+SuperMap Objects components to conduct secondary development, working out the logistics distribution system based on GIS. The system integrates the analytic function of GIS spatial information

Liu Yajing; Chen Xun

2010-01-01

455

Power Flow Analysis for Balanced and Unbalanced Radial Distribution Systems  

Microsoft Academic Search

This paper reports on an efficient method of power flow analysis for solving balanced and unbalanced radial distribution systems. The radial distribution system is modelled as a series of interconnected single feeders. Using Kirchoff's laws, a set of iterative power flow equations was developed to conduct the power flow studies. Due to the voltage dependency of loads in distribution systems,

H. M. Mok; S. Elangovan; M. M. A. Salama; Cao Longjian

456

Distribution system load flow using object-oriented methodology  

Microsoft Academic Search

Distribution system has been analyzed in this paper using object-oriented approach. The important contribution of this paper is the development of software objects for various distribution system components in such a way that they can be reused in most of the distribution system analysis programs. The design, proposed in this paper, is used for developing load flow analysis program. Object-oriented

M. P. Selvan; K. S. Swarup

2004-01-01

457

Comparative analysis for penetration of distributed generation in power systems  

Microsoft Academic Search

This paper addresses comparative analysis for penetration of distributed generation (DG) from the perspective of a distribution company (disco). Penetration of distributed generator (Size and location) is obtained through different approaches: Cost minimization and System Energy loss minimization. The methodology adopted permits the planner to decide optimal location and size of DG with compromise between System cost and System energy

Deependra Singh; K. S. Verma

2008-01-01

458

Amoeba: A Distributed Operating System for the 1990s  

Microsoft Academic Search

Amoeba is the distributed system developed at the Free University (VU) and Centre for Mathematics and Computer Science (CWI), both in Amsterdam. Throughout the project's ten-year history, a major concern of the designers has been to combine the research themes of distributed systems, such as high availability, use of parallelism and scalability, with simplicity and high performance. Distributed systems are

Sape J. Mullender; Guido Van Rossum; Andrew S. Tanenbaum; Robbert Van Renesse; Hans Van Staveren

1990-01-01

459

RODIN (Rigorous Open Development Environment for Complex Systems).  

National Technical Information Service (NTIS)

The overall objective of RODIN is to create a methodology and supporting open tool platform for cost-effective, rigorous development of complex, dependable software systems and services. The project focuses on tackling complexity caused by the environment...

J. Coleman C. Jones I. Oliver A. Romanovsky E. Troubitsyna

2005-01-01

460

Conserved current in Markovian open-quantum systems  

SciTech Connect

We reexamine the Markovian approximation of local current in open quantum systems, discussed recently by Gebauer and Car. Our derivation is more transparent; the proof of the current conservation becomes explicit and easy.

Bodor, Andras; Diosi, Lajos [Department of the Physics of Complex Systems, Eoetvoes University, H-1117 Budapest (Hungary); Research Institute for Particle and Nuclear Physics, H-1525 Budapest 114, P.O. Box 49 (Hungary)

2006-06-15

461

Rule-based management of distributed operating systems  

Microsoft Academic Search

This paper presents a paradigm for managing distributed operating system using a rule-based architecture. Recent trends have led to the structuring of operating systems, particularly those for distributed systems, as a set of microkernels with much of the system functionality being provided by a set of servers operating in user space. The proliferation of client-server based systems can easily lead

Mark D. Wood

1992-01-01

462

Air distribution effectiveness and thermal stratification with stratified air distribution systems  

Microsoft Academic Search

Stratified air distribution systems such as Traditional Displacement Ventilation (TDV) and Under-Floor Air Distribution (UFAD) have been known to provide better indoor air quality. This thesis examined the influence of several key design parameters of TDV and UFAD in air distribution effectiveness and thermal stratification. ^ First, the literature concerning the ventilation performance of the TDV and UFAD systems was

Ki Sup Lee

2011-01-01

463

Optimal reactive power flow with distributed generating plants in electric power distribution systems  

Microsoft Academic Search

This paper presents the solution of reactive power flow optimization for electric power distribution systems integrating with distributed generating (Distributed Generator: DG) plants which can support daily load demand. To reduce the total energy losses of the entire system, transformer tap and reactive power injection from available reactive power source are required. The setting of variables based on a particular

U. Leeton; T. Ratniyomchai; T. Kulworawanichpong

2010-01-01

464

Characterizing and Improving Distributed Intrusion Detection Systems.  

SciTech Connect

Due to ever-increasing quantities of information traversing networks, network administrators are developing greater reliance upon statistically sampled packet information as the source for their intrusion detection systems (IDS). Our research is aimed at understanding IDS performance when statistical packet sampling is used. Using the Snort IDS and a variety of data sets, we compared IDS results when an entire data set is used to the results when a statistically sampled subset of the data set is used. Generally speaking, IDS performance with statistically sampled information was shown to drop considerably even under fairly high sampling rates (such as 1:5). Characterizing and Improving Distributed Intrusion Detection Systems4AcknowledgementsThe authors wish to extend our gratitude to Matt Bishop and Chen-Nee Chuah of UC Davis for their guidance and support on this work. Our thanks are also extended to Jianning Mai of UC Davis and Tao Ye of Sprint Advanced Technology Labs for their generous assistance.We would also like to acknowledge our dataset sources, CRAWDAD and CAIDA, without which this work would not have been possible. Support for OC48 data collection is provided by DARPA, NSF, DHS, Cisco and CAIDA members.

Hurd, Steven A.; Proebstel, Elliot P.

2007-11-01

465

State Electricity Regulatory Policy and Distributed Resources: Distributed Resources and Electric System Reliability  

SciTech Connect

Designing and implementing credit-based pilot programs for distributed resources distribution is a low-cost, low-risk opportunity to find out how these resources can help defer or avoid costly electric power system (utility grid) distribution upgrades. This report describes implementation options for deaveraged distribution credits and distributed resource development zones. Developing workable programs implementing these policies can dramatically increase the deployment of distributed resources in ways that benefit distributed resource vendors, users, and distribution utilities. This report is one in the State Electricity Regulatory Policy and Distributed Resources series developed under contract to NREL (see Annual Technical Status Report of the Regulatory Assistance Project: September 2000-September 2001, NREL/SR-560-32733). Other titles in this series are: (1) Accommodating Distributed Resources in Wholesale Markets, NREL/SR-560-32497; (2) Distributed Resources and Electric System Re liability, NREL/SR-560-32498; (3) Distribution System Cost Methodologies for Distributed Generation, NREL/SR-560-32500; (4) Distribution System Cost Methodologies for Distributed Generation Appendices, NREL/SR-560-32501.

Cowart, R.; Harrington, C.; Moskovitz, D.; Shirley, W.; Weston, F.; Sedano, R.

2002-10-01

466

A Disk-Based System for Producing and Distributing Science Products from MODIS  

NASA Technical Reports Server (NTRS)

Since beginning operations in 1999, the MODIS Adaptive Processing System (MODAPS) has evolved to take advantage of trends in information technology, such as the falling cost of computing cycles and disk storage and the availability of high quality open-source software (Linux, Apache and Perl), to achieve substantial gains in processing and distribution capacity and throughput while driving down the cost of system operations.

Masuoka, Edward; Wolfe, Robert; Sinno, Scott; Ye Gang; Teague, Michael

2007-01-01

467

DisTec: Towards a Distributed System for Telecom Computing  

NASA Astrophysics Data System (ADS)

The continued exponential growth in both the volume and the complexity of information, compared with the computing capacity of the silicon-based devices restricted by Moore's Law, is giving birth to a new challenge to the specific requirements of analysts, researchers and intelligence providers. With respect to this challenge, a new class of techniques and computing platforms, such as Map-Reduce model, which mainly focus on scalability and parallelism, has been emerging. In this paper, to move the scientific prototype forward to practice, we elaborate a prototype of our applied distributed system, DisTec, for knowledge discovery from social network perspective in the field of telecommunications. The major infrastructure is constructed on Hadoop, an open-source counterpart of Google's Map-Reduce. We carefully devised our system to undertake the mining tasks in terabytes call records. To illustrate its functionality, DisTec is applied to real-world large-scale telecom dataset. The experiments range from initial raw data preprocessing to final knowledge extraction. We demonstrate that our system has a good performance in such cloud-scale data computing.

Yang, Shengqi; Wang, Bai; Zhao, Haizhou; Gao, Yuan; Wu, Bin

468

Audit considerations in distributed processing systems  

Microsoft Academic Search

Applications of distributed processing networks are proliferating rapidly. It is expected that by the year 2000, distributed networks will be one of the most significant developments to evolve from the computer revolution.Distributed networks are unique in that they bring together concepts of communication, engineering, and computing. From an audit standpoint, the complexities involved in control design and testing are challenging.

James V. Hansen

1983-01-01

469

Systems analysis of the space shuttle. [communication systems, computer systems, and power distribution  

NASA Technical Reports Server (NTRS)

Developments in communications systems, computer systems, and power distribution systems for the space shuttle are described. The use of high speed delta modulation for bit rate compression in the transmission of television signals is discussed. Simultaneous Multiprocessor Organization, an approach to computer organization, is presented. Methods of computer simulation and automatic malfunction detection for the shuttle power distribution system are also described.

Schilling, D. L.; Oh, S. J.; Thau, F.

1975-01-01

470

ROLF--An Open Learning Delivery System.  

ERIC Educational Resources Information Center

Discusses the Resourced Open Learning Facility (ROLF), which was developed by the U.K. Skills Training Agency (STA) as a means of delivering off-the-job skill training for the unemployed. Employment training is discussed and an evaluation of ROLF is described, including management issues and types of trainees. (Author/LRW)

Twining, John; And Others

1989-01-01

471

Open Systems Ada Technology (OSAT) Program.  

National Technical Information Service (NTIS)

Project objectives were to: convert the mission computer of an AV-8B to a COTS, open standards-based platform, develop/demonstrate an HOL OFP, compare the observed CEP from this demonstration with the AV-8B Fleet OFP CEP , integrate the data fusion integr...

D. Winter

2002-01-01

472

LVDC distribution system protection — Solutions, implementation and measurements  

Microsoft Academic Search

An LVDC (low voltage DC) distribution system is a promising technology to be used in future smart distribution system having high level cost-efficiency and reliability. Protection of an LVDC distribution system differs from the traditional 20\\/0.4 kV AC distribution network; direct current and IT network complicates the customer-end protection. This paper describes practical protection solutions for the LVDC network and

Pasi Salonen; Pasi Nuutinen; Pasi Peltoniemi; Jarmo Partanen

2009-01-01

473

OpenDanubia - An integrated, modular simulation system to support regional water resource management  

NASA Astrophysics Data System (ADS)

The already completed, multi-disciplinary research project GLOWA-Danube has developed a regional scale, integrated modeling system, which was successfully applied on the 77,000 km2 Upper Danube basin to investigate the impact of Global Change on both the natural and anthropogenic water cycle. At the end of the last project phase, the integrated modeling system was transferred into the open source project OpenDanubia, which now provides both the core system as well as all major model components to the general public. First, this will enable decision makers from government, business and management to use OpenDanubia as a tool for proactive management of water resources in the context of global change. Secondly, the model framework to support integrated simulations and all simulation models developed for OpenDanubia in the scope of GLOWA-Danube are further available for future developments and research questions. OpenDanubia allows for the investigation of water-related scenarios considering different ecological and economic aspects to support both scientists and policy makers to design policies for sustainable environmental management. OpenDanubia is designed as a framework-based, distributed system. The model system couples spatially distributed physical and socio-economic process during run-time, taking into account their mutual influence. To simulate the potential future impacts of Global Change on agriculture, industrial production, water supply, households and tourism businesses, so-called deep actor models are implemented in OpenDanubia. All important water-related fluxes and storages in the natural environment are implemented in OpenDanubia as spatially explicit, process-based modules. This includes the land surface water and energy balance, dynamic plant water uptake, ground water recharge and flow as well as river routing and reservoirs. Although the complete system is relatively demanding on data requirements and hardware requirements, the modular structure and the generic core system (Core Framework, Actor Framework) allows the application in new regions and the selection of a reduced number of modules for simulation. As part of the Open Source Initiative in GLOWA-Danube (opendanubia.glowa-danube.de) a comprehensive documentation for the system installation was created and both the program code of the framework and of all major components is licensed under the GNU General Public License. In addition, some helpful programs and scripts necessary for the operation and processing of input and result data sets are provided.

Muerth, M.; Waldmann, D.; Heinzeller, C.; Hennicker, R.; Mauser, W.

2012-04-01

474

Distributed Decision Support Systems: A Federalist Model of Cooperation  

Microsoft Academic Search

Although the DSS community generally shows interest in distributed computing when building decision support systems, the use of distributed technologies often remains limited to extension services added to traditional, local DSS functionalities. In other words, distributed computing rarely change the intrinsic (and local) behavior of the DSS. In this paper, we propose new distributed decision support strategies impacting the very

Alexandre Gachet; Pius Haettenschwiler

2003-01-01

475

Smart grid power system control in distributed generation environment  

Microsoft Academic Search

This paper discusses the general aspects of smart grids and focuses on some distribution level smart grid features, such as interconnection of distributed generation and active distribution management, using automated meter reading (AMR) systems in network management and power quality monitoring, application of power electronics in electricity distribution, plug-in vehicles as part of smart grids, and frequency based load control

Pertti Järventausta; Sami Repo; Antti Rautiainen; Jarmo Partanen

2010-01-01

476

An Open Simulation System Model for scientific applications  

NASA Technical Reports Server (NTRS)

A model for a generic and open environment for running multi-code or multi-application simulations - called the open Simulation System Model (OSSM) - is proposed and defined. This model attempts to meet the requirements of complex systems like the Numerical Propulsion Simulator System (NPSS). OSSM places no restrictions on the types of applications that can be integrated at any state of its evolution. This includes applications of different disciplines, fidelities, etc. An implementation strategy is proposed that starts with a basic prototype, and evolves over time to accommodate an increasing number of applications. Potential (standard) software is also identified which may aid in the design and implementation of the system.

Williams, Anthony D.

1995-01-01

477

Study of distributed computing system based on web services  

NASA Astrophysics Data System (ADS)

For the security issues in distributed computing applications, combined with Web Services management system design and implementation, based on the research of Web Services and its security technology, this paper designs a distributed computing test system based on Web Services, in detail describes its key technologies, which further validates the advantages of Web Services technology for the distributed computing in loosely coupled network environment.

Wang, Lu-Feng

2013-03-01

478

The development of oil loading distributed control system  

Microsoft Academic Search

Adopting a small distributed control system (DCS) structure, an oil loading distributed control system is developed, which is composed of the process management level and process control level. The hardware configuration, software function and the method of realizing distributed communication are presented. The technical approaches of optimizing loading process management and enhancing process control reliability are used, which are PLC

Aishe Shui

2000-01-01

479

Verification of distributed control systems in intelligent manufacturing  

Microsoft Academic Search

This paper presents an application of formal methods for validation of flexible manufacturing systems controlled by distributed controllers. A software tool verification environment for distributed applications (VEDA) is developed for modeling and verification of distributed control systems. The tool provides an integrated environment for formal, model-based verification of the execution control of function blocks following the new international standard IEC61499.

Valeriy Vyatkin; Hans-Michael Hanisch

2003-01-01

480

AC versus DC distribution systems- Did we get it right?  

SciTech Connect

We presently enjoy a predominantly ac electrical distribution system, the engineering basis for which was designed over 100 years ago. While ac distribution systems have served us well, we should periodically pause to assess what opportunities we have accepted or been denied by the overwhelming predominance of ac electrical power distribution systems. What opportunities could be obtained by engineering dc distribution into at least portions of our present system? What advantages of the present ac distribution system should be recognized and protected? This paper will focus on distribution within premise and low-voltage distribution systems. Specifically, we will address the conversion efficiency costs of adopting various premise ac and dc distribution system topologies. According to a simple predictive model formulated in this paper, premise residential dc distribution will incur unfavorable total conversion efficiency compared with existing ac premise distribution. However, if a residence is supplied by a fuel cell or another dc generator, the total conversion efficiency within a residential dc distribution system could be similar to, or even better than, that for ac distribution.

Hammerstrom, Donald J.

2007-06-28

481

OPTIMAL SCHEDULING OF BOOSTER DISINFECTION IN WATER DISTRIBUTION SYSTEMS  

EPA Science Inventory

Booster disinfection is the addition of disinfectant at locations distributed throughout a water distribution system. Such a strategy can reduce the mass of disinfectant required to maintain a detectable residual at points of consumption in the distribution system, which may lea...

482

Application and development of distribution automation system in TEPCO  

Microsoft Academic Search

With distribution automation system (DAS), switches of the distribution network are remotely monitored and controlled by computers installed at the control center in sales offices. Tokyo Electric Power Co., Inc. (TEPCO) has completed the installation of DAS to all of its sale offices in order to operate the distribution network most effectively. However, the configuration of DAS computer system was

Satoru Koizumi; Mutsumu Okumura; Toru Yanase

2005-01-01

483

Summary of Distributed Resources Impact on Power Delivery Systems  

Microsoft Academic Search

Because traditional electric power distribution systems have been designed assuming the primary substation is the sole source of power and short-circuit capacity, DR interconnection results in operating situations that do not occur in a conventional system. This paper discusses several system issues which may be encountered as DR penetrates into distribution systems. The voltage issues covered are the DR impact

Robert Saint; Roger C. Dugan; Jim Burke; Ljubomir A. Kojovic

2008-01-01

484

Typical automation functions and their distribution in automation systems  

Microsoft Academic Search

The reutilization of proven automation solutions for automation systems is an essential approach to increase the profitability of engineering services. Additionally, distributed systems are increasingly important in automation systems. For this reason, this paper focuses on the aspect of distributed systems combined with the reutilization of automation tasks and solutions in the domains of process and production automation. To address

Karin Eckert; Timo Frank; Thomas Hadlich; Alexander Fay; Birgit Vogel-Heuser; Christian Diedrich

2011-01-01

485

Wolf: a rollback algorithm for optimistic distributed simulation systems  

Microsoft Academic Search

Discrete event dynamical systems are used to model a number of engineering applications ranging from communication networks, distributed computing systems to manufacturing systems. A new analytical model is proposed for the analysis of asynchronous, optimistic distributed simulation of discrete event dynamical systems. The performance of traditional timewarp algorithms and that of a new rollback algorithm, Wolf, are examined in this

Vijay Madisetti; Jean Walrand; David Messerschmitt

1988-01-01

486

Design and Optimization of Distributed Control System using UML Model  

Microsoft Academic Search

The article discusses with the utilization of the UML language for project, realization and optimization of distributed control systems. The work is oriented on the part of distributed control system with embedded systems interconnected by the industrial bus CAN. The article describes the project methodology, UML model and optimization of the system according to the target function. Also example of

Jirí Kotzian; Vilém Srovnal

2004-01-01

487

The Information Bus - An Architecture for Extensible Distributed Systems  

Microsoft Academic Search

Research can rarely be performed on large-scale, distributed systems at the level of thousands of workstations. In this paper, we describe the motivating constraints, design principles, and architecture for an extensible, distributed system operating in such an environment. The constraints include continuous operation, dynamic system evolution, and integration with extant systems. The , our solution, is a novel synthesis of

Brian M. Oki; Manfred Pfluegl; Alex Siegel; Dale Skeen

1993-01-01

488

The Information Bus: an architecture for extensible distributed systems  

Microsoft Academic Search

Research can rarely be performed on large-scale, distributed systems at the level of thousands of workstations. In this paper, we describe the motivating constraints, design principles, and architecture for an extensible, distributed system operating in such an environment. The constraints include continuous operation, dynamic system evolution, and integration with extant systems. The , our solution, is a novel synthesis of

Brian Oki; Manfred Pfluegl; Alex Siegel; Dale Skeen

1994-01-01