Science.gov

Sample records for informal communication networks

  1. Information communication on complex networks

    NASA Astrophysics Data System (ADS)

    Igarashi, Akito; Kawamoto, Hiroki; Maruyama, Takahiro; Morioka, Atsushi; Naganuma, Yuki

    2013-02-01

    Since communication networks such as the Internet, which is regarded as a complex network, have recently become a huge scale and a lot of data pass through them, the improvement of packet routing strategies for transport is one of the most significant themes in the study of computer networks. It is especially important to find routing strategies which can bear as many traffic as possible without congestion in complex networks. First, using neural networks, we introduce a strategy for packet routing on complex networks, where path lengths and queue lengths in nodes are taken into account within a framework of statistical physics. Secondly, instead of using shortest paths, we propose efficient paths which avoid hubs, nodes with a great many degrees, on scale-free networks with a weight of each node. We improve the heuristic algorithm proposed by Danila et. al. which optimizes step by step routing properties on congestion by using the information of betweenness, the probability of paths passing through a node in all optimal paths which are defined according to a rule, and mitigates the congestion. We confirm the new heuristic algorithm which balances traffic on networks by achieving minimization of the maximum betweenness in much smaller number of iteration steps. Finally, We model virus spreading and data transfer on peer-to-peer (P2P) networks. Using mean-field approximation, we obtain an analytical formulation and emulate virus spreading on the network and compare the results with those of simulation. Moreover, we investigate the mitigation of information traffic congestion in the P2P networks.

  2. Networking Paradigms: Information Technology and Communication Studies.

    ERIC Educational Resources Information Center

    Howley, Kevin

    Communications media have long been acknowledged as the site of intense political struggle over issues of access to, control over, and representations in these media. That communications research is likewise the site of struggle between the various paradigms of the discipline is, however, troubling to the neophyte communication scholar. For well…

  3. Gender, Information and Communication Networks: Implications for Extension.

    ERIC Educational Resources Information Center

    Subedi, A.; Garforth, Chr.

    1996-01-01

    In Nepal a study of 243 female and 179 male farmers showed that males demonstrated horizontal communication patterns among themselves; females actively sought information in both horizontal and heterogeneous patterns. Extension strategies that take advantage of gender-based networks were suggested to increase the flow of information. (SK)

  4. Basic limits on protocol information in data communications networks

    NASA Technical Reports Server (NTRS)

    Gallager, R. G.

    1976-01-01

    The paper considers basic limitations on the amount of protocol information that must be transmitted in a data communication network to keep track of source and receiver addresses and of the starting and stopping of messages. Assuming Poisson message arrivals between each communicating source-receiver pair, a lower bound is found on the required protocol information for message. This lower bound is the sum of two terms, one for the message-length information, which depends only on the distribution of message lengths, and the other for the message-start information, which depends only on the product of the source-receiver pair arrival rate and the expected delay for transmitting the message. Two strategies are developed which, in the limit of large numbers of sources and receivers, almost meet the lower bound on protocol information.

  5. Directedness of Information Flow in Mobile Phone Communication Networks

    PubMed Central

    Peruani, Fernando; Tabourier, Lionel

    2011-01-01

    Without having direct access to the information that is being exchanged, traces of information flow can be obtained by looking at temporal sequences of user interactions. These sequences can be represented as causality trees whose statistics result from a complex interplay between the topology of the underlying (social) network and the time correlations among the communications. Here, we study causality trees in mobile-phone data, which can be represented as a dynamical directed network. This representation of the data reveals the existence of super-spreaders and super-receivers. We show that the tree statistics, respectively the information spreading process, are extremely sensitive to the in-out degree correlation exhibited by the users. We also learn that a given information, e.g., a rumor, would require users to retransmit it for more than 30 hours in order to cover a macroscopic fraction of the system. Our analysis indicates that topological node-node correlations of the underlying social network, while allowing the existence of information loops, they also promote information spreading. Temporal correlations, and therefore causality effects, are only visible as local phenomena and during short time scales. Consequently, the very idea that there is (intentional) information spreading beyond a small vecinity is called into question. These results are obtained through a combination of theory and data analysis techniques. PMID:22216128

  6. Intelligent communication systems sensor scheduling based on network information

    NASA Astrophysics Data System (ADS)

    Blasch, Erik P.; Hoff, Andrew

    2004-04-01

    Increased reliance on data communications has driven the need for a higher capacity solution to transmit data. Many decision making problems include various types of data (i.e. video, text), which require an intelligent way to transfer the data across a communication system. Data fusion can be performed at the transmitting end to reduce the dimensionality of the data transferred; however if there are errors, the receiving end would have no way to search through the pedigree of information to correct the problem. Thus, a desired analysis is to be able to transfer all the data types, while achieving the "Quality of Service" metrics of throughput, delay, delay variation, probability of error, and cost. One way to solve this problem is by using the Asynchronous Transfer Mode network data scheduling. An ATM network allows multiple types of data to be sent over the same system with dynamic bandwidth allocation. The following paper provides a description of an intelligent scheduling model to enhance the capability to transmit data for fusion analysis.

  7. Advanced information processing system: Authentication protocols for network communication

    NASA Technical Reports Server (NTRS)

    Harper, Richard E.; Adams, Stuart J.; Babikyan, Carol A.; Butler, Bryan P.; Clark, Anne L.; Lala, Jaynarayan H.

    1994-01-01

    In safety critical I/O and intercomputer communication networks, reliable message transmission is an important concern. Difficulties of communication and fault identification in networks arise primarily because the sender of a transmission cannot be identified with certainty, an intermediate node can corrupt a message without certainty of detection, and a babbling node cannot be identified and silenced without lengthy diagnosis and reconfiguration . Authentication protocols use digital signature techniques to verify the authenticity of messages with high probability. Such protocols appear to provide an efficient solution to many of these problems. The objective of this program is to develop, demonstrate, and evaluate intercomputer communication architectures which employ authentication. As a context for the evaluation, the authentication protocol-based communication concept was demonstrated under this program by hosting a real-time flight critical guidance, navigation and control algorithm on a distributed, heterogeneous, mixed redundancy system of workstations and embedded fault-tolerant computers.

  8. Grower Communication Networks: Information Sources for Organic Farmers

    ERIC Educational Resources Information Center

    Crawford, Chelsi; Grossman, Julie; Warren, Sarah T.; Cubbage, Fred

    2015-01-01

    This article reports on a study to determine which information sources organic growers use to inform farming practices by conducting in-depth semi-structured interviews with 23 organic farmers across 17 North Carolina counties. Effective information sources included: networking, agricultural organizations, universities, conferences, Extension, Web…

  9. David Meets Goliath on the Information Superhighway: Venezuela in the Context of the Electronic Communication Networks.

    ERIC Educational Resources Information Center

    Sanchez-Vegas, Saadia

    1995-01-01

    Discusses Venezuela's information and communications technology infrastructure and usage patterns; examines future networking plans; and addresses political and economic considerations linked to the information and technology problems in Venezuela and in Latin America in general. (LRW)

  10. In-House Communication Support System Based on the Information Propagation Model Utilizes Social Network

    NASA Astrophysics Data System (ADS)

    Takeuchi, Susumu; Teranishi, Yuuichi; Harumoto, Kaname; Shimojo, Shinji

    Almost all companies are now utilizing computer networks to support speedier and more effective in-house information-sharing and communication. However, existing systems are designed to support communications only within the same department. Therefore, in our research, we propose an in-house communication support system which is based on the “Information Propagation Model (IPM).” The IPM is proposed to realize word-of-mouth communication in a social network, and to support information-sharing on the network. By applying the system in a real company, we found that information could be exchanged between different and unrelated departments, and such exchanges of information could help to build new relationships between the users who are apart on the social network.

  11. Health care communication networks: disseminating employee information for hospital security.

    PubMed

    Sumner, Jennifer; Liberman, Aaron; Rotarius, Timothy; Wan, Thomas T H; Eaglin, Ronald

    2009-01-01

    Health care in the United States is a system that, organizationally speaking, is fragmented. Each hospital facility is independently operated and is responsible for the hiring of its own employees. Corrupt individuals can take advantage of this fragmentation and move from hospital to hospital, gaining employment while hiding previous employment history. However, the need to exchange pertinent information regarding employees will become necessary as hospitals seek to fill positions throughout their organizations. One way to promote this information exchange is to develop trusted information sharing networks among hospital units. This study examined the problems surrounding organizational information sharing and the cultural factors necessary to enhance the exchange of employee information. Surveys were disseminated to 2,603 hospital chief executive officers and chief information officers throughout the nation. A sample of 154 respondents provided data into their current hiring practices and on their willingness to engage in the sharing of employee information. Findings indicated that, although fear of defamation and privacy violations do hinder the exchange of information between hospitals during the hiring process, by increasing external trust, linking the sharing process with the organizational goals of the hospital, and developing a "sharing culture" among hospitals, the exchange of employee information could be enhanced. PMID:19910705

  12. Communication networks

    NASA Astrophysics Data System (ADS)

    Kennedy, R. S.; Wagner, S. S.; Sia, E. B.

    1984-01-01

    A research program to determine and demonstrate the principles to be followed in the design of local communication networks as typified by local area networks, private branch exchanges and internetted collections of such structures is planned. Two fundamental assumptions distinguish the research from much of the ongoing work: (1) a single integrated system is to provide a set of highly diverse communication services such as interactive terminal service, data base access, file transfers, graphics, and voice and video; and (2) a single mode optical fiber links with very wide bandwidths is economical. These assumptions are not satisfied by the networks now being designed, but based upon the perceived trend toward such integrated diverse services and the declining cost of single mode fiber technology. It is planned for the research to involve theoretical, experimental, and design activities.

  13. Communications Network

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The Multi-Compatible Network Interface Unit (MCNIU) is intended to connect the space station's communications and tracking, guidance and navigation, life support, electric power, payload data, hand controls, display consoles and other systems, and also communicate with diverse processors. Honeywell is now marketing MCNIU commercially. It has applicability in certain military operations or civil control centers. It has nongovernment utility among large companies, universities and research organizations that transfer large amounts of data among workstations and computers. *This product is no longer commercially available.

  14. NASA Communications Augmentation network

    NASA Astrophysics Data System (ADS)

    Omidyar, Guy C.; Butler, Thomas E.; Laios, Straton C.

    1990-09-01

    The NASA Communications (Nascom) Division of the Mission Operations and Data Systems Directorate (MO&DSD) is to undertake a major initiative to develop the Nascom Augmentation (NAUG) network to achieve its long-range service objectives for operational data transport to support the Space Station Freedom Program, the Earth Observing System (EOS), and other projects. The NAUG is the Nascom ground communications network being developed to accommodate the operational traffic of the mid-1990s and beyond. The NAUG network development will be based on the Open Systems Interconnection Reference Model (OSI-RM). This paper describes the NAUG network architecture, subsystems, topology, and services; addresses issues of internetworking the Nascom network with other elements of the Space Station Information System (SSIS); discusses the operations environment. This paper also notes the areas of related research and presents the current conception of how the network will provide broadband services in 1998.

  15. NASA Communications Augmentation network

    NASA Technical Reports Server (NTRS)

    Omidyar, Guy C.; Butler, Thomas E.; Laios, Straton C.

    1990-01-01

    The NASA Communications (Nascom) Division of the Mission Operations and Data Systems Directorate (MO&DSD) is to undertake a major initiative to develop the Nascom Augmentation (NAUG) network to achieve its long-range service objectives for operational data transport to support the Space Station Freedom Program, the Earth Observing System (EOS), and other projects. The NAUG is the Nascom ground communications network being developed to accommodate the operational traffic of the mid-1990s and beyond. The NAUG network development will be based on the Open Systems Interconnection Reference Model (OSI-RM). This paper describes the NAUG network architecture, subsystems, topology, and services; addresses issues of internetworking the Nascom network with other elements of the Space Station Information System (SSIS); discusses the operations environment. This paper also notes the areas of related research and presents the current conception of how the network will provide broadband services in 1998.

  16. Regional-technical information network system by PC-based communication 'Kougi Net Niigata'

    NASA Astrophysics Data System (ADS)

    Tanaka, Koichi; Kitagawa, Yoichi; Hoshino, Kimiaki

    'Regional-technical information' database was constructed by Industrial research institute of Niigata prefecture. This is available for industries in our prefecture with our PC-based communication network system. And also, it provides communication measures called BBS and electronic mail service with which they can communicate each other. This system is considered to give three effects. First of all, they can get technical information required in regional industries that is not provided by commercial database at their office or factory speedy and correctly. Secondly, they can easily survey technical background of local industries they want to take into partnership in their extension of work. Thirdly, since it provides a place where they can exchange information each other, it promotes their development of new commercial products and partnership.

  17. Informing the network: Improving communication with interface communities during wildland fire

    USGS Publications Warehouse

    Taylor, J.G.; Gillette, S.C.; Hodgson, R.W.; Downing, J.L.; Burns, M.R.; Chavez, D.J.; Hogan, J.T.

    2007-01-01

    An interagency research team studied fire communications that took place during different stages of two wildfires in southern California: one small fire of short duration and one large fire of long duration. This "quick- response" research showed that pre-fire communication planning was particularly effective for smaller fire events and parts of that planning proved invaluable for the large fire event as well. Information seeking by the affected public relied on locally convenient sources during the small fire. During the large fire, widespread evacuations disrupted many of the local informal communication networks. Residents' needs were for "real-time, " place-specific information: precise location, severity, size, and direction of spread of the fires. Fire management agencies must contribute real-time, place-specific fire information when it is most needed by the affected public, as they try to make sense out of the chaos of a wildland fire. Disseminating fire information as broadly as possible through multiple pathways will maximize the probability of the public finding the information they need. ?? Society for Human Ecology.

  18. Computer Communication Networks and Their Use for Information Retrieval and Dissemination: Basic Tutorial and Current Scenario of Networks in India.

    ERIC Educational Resources Information Center

    Arora, Jagdish; And Others

    1992-01-01

    Offers a tutorial on telecommunications that covers the basic concepts, types, techniques, and protocols of data communications. Current scenarios for computer communications networks, their connectivity to global telecommunication environments, and global online retrieval services are discussed. Ten data communication networks and seven online…

  19. Communicability across evolving networks

    NASA Astrophysics Data System (ADS)

    Grindrod, Peter; Parsons, Mark C.; Higham, Desmond J.; Estrada, Ernesto

    2011-04-01

    Many natural and technological applications generate time-ordered sequences of networks, defined over a fixed set of nodes; for example, time-stamped information about “who phoned who” or “who came into contact with who” arise naturally in studies of communication and the spread of disease. Concepts and algorithms for static networks do not immediately carry through to this dynamic setting. For example, suppose A and B interact in the morning, and then B and C interact in the afternoon. Information, or disease, may then pass from A to C, but not vice versa. This subtlety is lost if we simply summarize using the daily aggregate network given by the chain A-B-C. However, using a natural definition of a walk on an evolving network, we show that classic centrality measures from the static setting can be extended in a computationally convenient manner. In particular, communicability indices can be computed to summarize the ability of each node to broadcast and receive information. The computations involve basic operations in linear algebra, and the asymmetry caused by time’s arrow is captured naturally through the noncommutativity of matrix-matrix multiplication. Illustrative examples are given for both synthetic and real-world communication data sets. We also discuss the use of the new centrality measures for real-time monitoring and prediction.

  20. Experiences with using information and communication technology to build a multi-municipal support network for informal carers.

    PubMed

    Torp, Steffen; Bing-Jonsson, Pia C; Hanson, Elizabeth

    2013-09-01

    This multi-municipal intervention study explored whether informal carers of frail older people and disabled children living at home made use of information and communication technology (ICT) to gain knowledge about caring and to form informal support networks, thereby improving their health. Seventy-nine informal carers accessed web-based information about caring and an e-based discussion forum via their personal computers. They were able to maintain contact with each other using a web camera and via normal group meetings. After the first 12 months, 17 informal carers participated in focus group interviews and completed a short questionnaire. Four staff members were also interviewed. Participant carers who had prior experiences with a similar ICT-based support network reported greater satisfaction and more extensive use of the network than did participants with no such prior experience. It seems that infrequent usage of the service may be explained by too few other carers to identify with and inappropriate recruitment procedures. Nevertheless, carers of disabled children reported that the intervention had resulted in improved services across the participant municipalities. To achieve optimal effects of an ICT-based support network due attention must be given to recruitment processes and social environment building for which care practitioners require training and support. PMID:23245624

  1. A universal quantum information processor for scalable quantum communication and networks.

    PubMed

    Yang, Xihua; Xue, Bolin; Zhang, Junxiang; Zhu, Shiyao

    2014-01-01

    Entanglement provides an essential resource for quantum computation, quantum communication, and quantum networks. How to conveniently and efficiently realize the generation, distribution, storage, retrieval, and control of multipartite entanglement is the basic requirement for realistic quantum information processing. Here, we present a theoretical proposal to efficiently and conveniently achieve a universal quantum information processor (QIP) via atomic coherence in an atomic ensemble. The atomic coherence, produced through electromagnetically induced transparency (EIT) in the Λ-type configuration, acts as the QIP and has full functions of quantum beam splitter, quantum frequency converter, quantum entangler, and quantum repeater. By employing EIT-based nondegenerate four-wave mixing processes, the generation, exchange, distribution, and manipulation of light-light, atom-light, and atom-atom multipartite entanglement can be efficiently and flexibly achieved in a deterministic way with only coherent light fields. This method greatly facilitates the operations in quantum information processing, and holds promising applications in realistic scalable quantum communication and quantum networks. PMID:25316514

  2. General practice and the Internet revolution. Use of an Internet social network to communicate information on prevention in France.

    PubMed

    Veuillotte, Isabelle; Morel, Gilles; Pitois, Stephane; Haler, Renaud; Mercier, Patricia; Aubry, Catherine; Cannet, Didier

    2015-03-01

    The popularity of social networks and the huge number of exchanges have made them immensely important for the communication of information. This French study explored prevention in hereditary breast cancer using a social Internet network to communicate information. The principal objective was to inform French women aged from 20 to 50 years, using the social network Facebook, about the warning signs of breast cancer in cases of a predisposition to the disease due to a genetic mutation. The secondary objectives were to inform people about screening. An information page entitled "hereditary breast cancer: and if I was concerned?" was distributed in 3 different ways: from friend to friend, via groups of persons, and by targeted advertising. Four articles and 11 messages were distributed over 27 days. The total number of visits for this period amounted to 1019. A total of 81 percent of the Internauts were women and 55 percent of the visitors were aged between 25 and 44 years. Other information campaigns concerning public health issues could be conducted using this tool. A legal framework is necessary to preserve the quality of the medical information provided. This new means of communication, used for prevention purposes, will add to other frequently used methods of communication. PMID:25784641

  3. Digital information and communication networks and scientific research substance: An investigation of meteorology

    NASA Astrophysics Data System (ADS)

    Shen, Yi

    This study investigated research meteorologists' current usage and evaluation of information and communication technologies (ICT) in performing research tasks and the current relationship between meteorologists' ICT use and content characteristics of their research outputs. It surveyed research meteorologists working in three NOAA funded research institutes based at universities. Follow-up interviews with two selective samples of the survey participants were conducted to provide additional evidence to survey results and make suggestions for future measurement development work. Multiple regression analysis was performed to test the hypothesized relationships between meteorologists' ICT use and two substantive characteristics of their research---data integration and intra-/interdisciplinarity. Descriptive statistics were calculated to discern inferences of the scientists' current state of use and their degree of satisfaction with ICT tools. Follow-up interviews were transcribed and analyzed qualitatively with open coding and axial coding. The study findings contradicted the two assumptions of ICT effects on meteorological research by showing that the greater frequency of networked ICT use is not significantly associated with either greater data integration in research analysis, or greater intra- or interdisciplinary research. The major ICT barrier is the lack of a data and information infrastructure and support system for integrated, standardized, specialized, and easily accessible data and information from distributed servers. Suggestions were provided on the improvements of technical, social, political, and educational settings to promote large-scale date integration and intra-/interdisciplinary research. By moving further from theoretical assumptions to practical examinations, the research findings provide empirical evidence of Bowker's theories on the social shaping and social impact of infrastructure in sciences and affirmed some of Bowker's arguments regarding

  4. Data communication network optimization

    SciTech Connect

    Hessel, S.R.

    1987-01-01

    Research that will ultimately improve the quality of the decisions made in the design of packet-data communication networks is described. Three topics are specifically addressed: an unusually general method of optimizing networks is developed; a network model is developed that facilitates the optimization and it itself valuable; and the statistical nature of the data-communication traffic on networks is examined to support the model. The model permits the analysis of delays in heterogeneous networks of complex topology. The focus of this dissertation is on the optimization of networks. The optimization is built upon the model. The algorithm varies capacity and routing to minimize network cost. The capacity-assignment algorithm developed is an iterative algorithm that allows arbitrarily complex queuing models to be used. It is because of this algorithm that the optimization can be applied to a wide range of heterogeneous network. The routing algorithms is basically the flow deviation algorithm of Gerla.

  5. Communication Network Analysis Methods.

    ERIC Educational Resources Information Center

    Farace, Richard V.; Mabee, Timothy

    This paper reviews a variety of analytic procedures that can be applied to network data, discussing the assumptions and usefulness of each procedure when applied to the complexity of human communication. Special attention is paid to the network properties measured or implied by each procedure. Factor analysis and multidimensional scaling are among…

  6. Secure Communication with Network Coding

    NASA Astrophysics Data System (ADS)

    Cao, Zhanghua; Tang, Yuansheng; Luo, Jinquan

    In this paper, we consider the problem of secure communication over wiretap multicast networks. Noticing that network coding renders the intermediate nodes to mix information from different data flows, we propose a secure communication scheme based on cryptographic means and network coding. Specifically, we employ a confidential cryptosystem to encrypt the source message packets, then treat the secret key as a message packet and mix the key with the obtained cryptograms. Furthermore, we can prove that, under suitable conditions, the wiretapper is unable to gain the secret key. Meanwhile, the confidential cryptosystem prohibits the wiretapper from extracting meaningful information from the obtained cryptograms. Our scheme doesn't need a private channel to transmit the secret key and enables the utilization of network capacity to reach 1 n n.

  7. An Information Processing Model of Organizations: A Focus on Environmental Uncertainty and Communication Network Structuring.

    ERIC Educational Resources Information Center

    Danowski, James A.

    In this paper, an information processing model of social systems is developed with particular concern for large complex organizations. In explicating the sixteen assumptions and propositions of the model, the literature on environmental uncertainty, interorganizational communication, technology, and their effects on internal organizational…

  8. Hyperswitch Communication Network Computer

    NASA Technical Reports Server (NTRS)

    Peterson, John C.; Chow, Edward T.; Priel, Moshe; Upchurch, Edwin T.

    1993-01-01

    Hyperswitch Communications Network (HCN) computer is prototype multiple-processor computer being developed. Incorporates improved version of hyperswitch communication network described in "Hyperswitch Network For Hypercube Computer" (NPO-16905). Designed to support high-level software and expansion of itself. HCN computer is message-passing, multiple-instruction/multiple-data computer offering significant advantages over older single-processor and bus-based multiple-processor computers, with respect to price/performance ratio, reliability, availability, and manufacturing. Design of HCN operating-system software provides flexible computing environment accommodating both parallel and distributed processing. Also achieves balance among following competing factors; performance in processing and communications, ease of use, and tolerance of (and recovery from) faults.

  9. Timely redistribution of information for epidemiological surveillance and alert: the experience from the French communicable diseases network.

    PubMed Central

    Valleron, Alain-Jacques; Vidal, Jaques J.

    2002-01-01

    Since 1984 the French Communicable Disease Network (FCDN) collects and analyses epidemiological information obtained online from a team of "Sentinel General Practitioners" (SGPs). It redistributes this information in the form of standardised weekly incidence estimates. These weekly estimates now appear on the Internet and are the basis for issuing alerts of influenza epidemics. We postulate that day to day estimations would be highly desirable to achieve timely detection of the actual onset of the epidemic, a need dramatically underscored by the emergence of bioterrorism. The present paper suggests the feasibility of reconstructing daily epidemiological information using local smoothing with a suitable spline function to obtain short latency alert messages. PMID:12463941

  10. Multiuser quantum communication networks

    SciTech Connect

    Wojcik, Antoni; Kurzynski, Pawel; Grudka, Andrzej; Luczak, Tomasz; Gdala, Tomasz; Bednarska, Malgorzata

    2007-02-15

    We study a quantum state transfer between spins interacting with an arbitrary network of spins coupled by uniform XX interactions. It is shown that in such a system under fairly general conditions, we can expect a nearly perfect transfer of states. Then we analyze a generalization of this model to the case of many network users, where the sender can choose which party he wants to communicate with by appropriately tuning his local magnetic field. We also remark that a similar idea can be used to create an entanglement between several spins coupled to the network.

  11. Terminal-oriented computer-communication networks.

    NASA Technical Reports Server (NTRS)

    Schwartz, M.; Boorstyn, R. R.; Pickholtz, R. L.

    1972-01-01

    Four examples of currently operating computer-communication networks are described in this tutorial paper. They include the TYMNET network, the GE Information Services network, the NASDAQ over-the-counter stock-quotation system, and the Computer Sciences Infonet. These networks all use programmable concentrators for combining a multiplicity of terminals. Included in the discussion for each network is a description of the overall network structure, the handling and transmission of messages, communication requirements, routing and reliability consideration where applicable, operating data and design specifications where available, and unique design features in the area of computer communications.

  12. Simulator of Space Communication Networks

    NASA Technical Reports Server (NTRS)

    Clare, Loren; Jennings, Esther; Gao, Jay; Segui, John; Kwong, Winston

    2005-01-01

    Multimission Advanced Communications Hybrid Environment for Test and Evaluation (MACHETE) is a suite of software tools that simulates the behaviors of communication networks to be used in space exploration, and predict the performance of established and emerging space communication protocols and services. MACHETE consists of four general software systems: (1) a system for kinematic modeling of planetary and spacecraft motions; (2) a system for characterizing the engineering impact on the bandwidth and reliability of deep-space and in-situ communication links; (3) a system for generating traffic loads and modeling of protocol behaviors and state machines; and (4) a system of user-interface for performance metric visualizations. The kinematic-modeling system makes it possible to characterize space link connectivity effects, including occultations and signal losses arising from dynamic slant-range changes and antenna radiation patterns. The link-engineering system also accounts for antenna radiation patterns and other phenomena, including modulations, data rates, coding, noise, and multipath fading. The protocol system utilizes information from the kinematic-modeling and link-engineering systems to simulate operational scenarios of space missions and evaluate overall network performance. In addition, a Communications Effect Server (CES) interface for MACHETE has been developed to facilitate hybrid simulation of space communication networks with actual flight/ground software/hardware embedded in the overall system.

  13. Communication Structure of Cortical Networks

    PubMed Central

    da Fontoura Costa, Luciano; Batista, João Luiz B.; Ascoli, Giorgio A.

    2011-01-01

    Large-scale cortical networks exhibit characteristic topological properties that shape communication between brain regions and global cortical dynamics. Analysis of complex networks allows the description of connectedness, distance, clustering, and centrality that reveal different aspects of how the network's nodes communicate. Here, we focus on a novel analysis of complex walks in a series of mammalian cortical networks that model potential dynamics of information flow between individual brain regions. We introduce two new measures called absorption and driftness. Absorption is the average length of random walks between any two nodes, and takes into account all paths that may diffuse activity throughout the network. Driftness is the ratio between absorption and the corresponding shortest path length. For a given node of the network, we also define four related measurements, namely in- and out-absorption as well as in- and out-driftness, as the averages of the corresponding measures from all nodes to that node, and from that node to all nodes, respectively. We find that the cat thalamo-cortical system incorporates features of two classic network topologies, Erdös–Rényi graphs with respect to in-absorption and in-driftness, and configuration models with respect to out-absorption and out-driftness. Moreover, taken together these four measures separate the network nodes based on broad functional roles (visual, auditory, somatomotor, and frontolimbic). PMID:21427794

  14. The social network and the geo-hydrological information: the CNR IRPI Facebook page as example of communication.

    NASA Astrophysics Data System (ADS)

    Fiorucci, Federica; Bianchi, Cinzia; Marchesini, Ivan; Salvati, Paola; Fugnoli, Federico; Guzzetti, Fausto

    2014-05-01

    Good communication is a fundamental step for the spread of news and knowledge. The effectiveness and persuasiveness of a message is a function of the interaction of characteristics of the audience, the source of the message, and content of the message. Italian Research Institute for the Hydrogeological Protection (CNR-IRPI) has been publishing information on geo-hydrological events using the Internet (http://sici.irpi.cnr.it/, http://webmap.irpi.cnr.it/, http://geomorphology.irpi.cnr.it/, http://polaris.irpi.cnr.it/, http://giida.irpi.cnr.it/, http://events.irpi.cnr.it/ ). Our websites are mainly visited by experts and the information are used for technical purposes. The contents and the interface of the websites are designed for this type of users. Our intention is to increase the type of users, and we are testing the use of social network to catch the wide public's attention. Social networks have emerged as critical factor in information dissemination, search, marketing expertise and influence discovery, and are an important channel for people to share information. Social scientist have long recognized the importance of social networks in the spread of information. Facebook and Twitter are the most widely used social networking services. They make it simpler to communicate with multiple people at one time. Social media may also make it easier for users to monitor activities of people (friends or followers). An official Facebook page of the Italian Research Institute for the Hydrogeological Protection (CNR-IRPI, https://www.facebook.com/CNR.IRPI ), was created and linked to a Twitter account. The purpose of this page is to disseminate information on flood and landslide events and on our research activities, in order to raise awareness of geo-hydrological matters among users. This page publishes news on current or historical landslide and flood events involving the Italian territory, or news from around the world collected on the network. The news are published as

  15. Communications networks in stressed environments

    NASA Astrophysics Data System (ADS)

    Rappaport, Stephen S.; Robertazzi, T. G.

    1993-12-01

    Communications techniques and performance models are devised for communications networks in which mobile platforms, volatile traffic patterns, and interference are significant features. The main focus is on network organization and control configurations that support communications among semi-autonomous mobile platforms. Example platforms can support data gathering sensors and communications equipment aboard guided or maneuverable space vehicles satellites, aircraft, ships, or grounded vehicles or persons. Network configurations with limited and/or shared communications resources are considered. Analytical models are devised to characterize major performance issues. Matters of concern include maintaining network connectivity with mobile platforms that have active communications links, methods for allocating communications resources to gateways, dynamic assignment of resources, and access rights. Topics investigated have included: acquisition of spread spectrum signals, low-delay channel access protocols, call hand-off schemes, telecommunications traffic performance of mobile networks, computation vs. communication considerations, high speed packet switching, and aspects of self-organizing communications networks.

  16. Spread spectrum communication networks

    NASA Astrophysics Data System (ADS)

    Pursley, Michael B.; Sarwate, Dilip V.

    1991-02-01

    One of the difficulties that arises in the analysis of codeword and packet error probabilities in asynchronous frequency-hop (FH) multiple-access communication systems and networks is the statistical dependence between symbol errors within a codeword or packet in FH communications with multiple symbols per dwell interval. The basic problem is that the hits by other transmissions are statistically dependent. In one paper, we developed improved bounds on the codeword error probability for such FH multiple-access systems and networks. This was accomplished by investigating models in which hits are conditionally independent given the number of interfering packets and choosing the conditional probability of a hit in such a way that a bound on the performance of the actual system can be obtained. We showed that if the ratio of the number of interfering packets to the number of frequency slots is held constant, hits the asynchronous FH networks are asymptotically independent in the limits as the number of frequency slots increases. Thus, when the number of frequency slots is large, the error probabilities can be closely approximated by using the simplified model with independent hits. We published a related paper which shows that, contrary to a paper published by another author, the sequence of hits in an asynchronous FH multiple-access communication system does not form a Markov process.

  17. NASA technology transfer network communications and information system: TUNS user survey

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Applied Expertise surveyed the users of the deployed Technology Utilization Network System (TUNS) and surveyed prospective new users in order to gather background information for developing the Concept Document of the system that will upgrade and replace TUNS. Survey participants broadly agree that automated mechanisms for acquiring, managing, and disseminating new technology and spinoff benefits information can and should play an important role in meeting NASA technology utilization goals. However, TUNS does not meet this need for most users. The survey describes a number of systematic improvements that will make it easier to use the technology transfer mechanism, and thus expedite the collection and dissemination of technology information. The survey identified 26 suggestions for enhancing the technology transfer system and related processes.

  18. The National Institutes of Health Clinical Center Digital Imaging Network, Picture Archival and Communication System, and Radiology Information System.

    PubMed

    Goldszal, A F; Brown, G K; McDonald, H J; Vucich, J J; Staab, E V

    2001-06-01

    In this work, we describe the digital imaging network (DIN), picture archival and communication system (PACS), and radiology information system (RIS) currently being implemented at the Clinical Center, National Institutes of Health (NIH). These systems are presently in clinical operation. The DIN is a redundant meshed network designed to address gigabit density and expected high bandwidth requirements for image transfer and server aggregation. The PACS projected workload is 5.0 TB of new imaging data per year. Its architecture consists of a central, high-throughput Digital Imaging and Communications in Medicine (DICOM) data repository and distributed redundant array of inexpensive disks (RAID) servers employing fiber-channel technology for immediate delivery of imaging data. On demand distribution of images and reports to clinicians and researchers is accomplished via a clustered web server. The RIS follows a client-server model and provides tools to order exams, schedule resources, retrieve and review results, and generate management reports. The RIS-hospital information system (HIS) interfaces include admissions, discharges, and transfers (ATDs)/demographics, orders, appointment notifications, doctors update, and results. PMID:11442088

  19. Hyperswitch communication network

    NASA Technical Reports Server (NTRS)

    Peterson, J.; Pniel, M.; Upchurch, E.

    1991-01-01

    The Hyperswitch Communication Network (HCN) is a large scale parallel computer prototype being developed at JPL. Commercial versions of the HCN computer are planned. The HCN computer being designed is a message passing multiple instruction multiple data (MIMD) computer, and offers many advantages in price-performance ratio, reliability and availability, and manufacturing over traditional uniprocessors and bus based multiprocessors. The design of the HCN operating system is a uniquely flexible environment that combines both parallel processing and distributed processing. This programming paradigm can achieve a balance among the following competing factors: performance in processing and communications, user friendliness, and fault tolerance. The prototype is being designed to accommodate a maximum of 64 state of the art microprocessors. The HCN is classified as a distributed supercomputer. The HCN system is described, and the performance/cost analysis and other competing factors within the system design are reviewed.

  20. The physics of communicability in complex networks

    NASA Astrophysics Data System (ADS)

    Estrada, Ernesto; Hatano, Naomichi; Benzi, Michele

    2012-05-01

    A fundamental problem in the study of complex networks is to provide quantitative measures of correlation and information flow between different parts of a system. To this end, several notions of communicability have been introduced and applied to a wide variety of real-world networks in recent years. Several such communicability functions are reviewed in this paper. It is emphasized that communication and correlation in networks can take place through many more routes than the shortest paths, a fact that may not have been sufficiently appreciated in previously proposed correlation measures. In contrast to these, the communicability measures reviewed in this paper are defined by taking into account all possible routes between two nodes, assigning smaller weights to longer ones. This point of view naturally leads to the definition of communicability in terms of matrix functions, such as the exponential, resolvent, and hyperbolic functions, in which the matrix argument is either the adjacency matrix or the graph Laplacian associated with the network. Considerable insight on communicability can be gained by modeling a network as a system of oscillators and deriving physical interpretations, both classical and quantum-mechanical, of various communicability functions. Applications of communicability measures to the analysis of complex systems are illustrated on a variety of biological, physical and social networks. The last part of the paper is devoted to a review of the notion of locality in complex networks and to computational aspects that by exploiting sparsity can greatly reduce the computational efforts for the calculation of communicability functions for large networks.

  1. Information Computer Communications Policy, 2: The Usage of International Data Networks in Europe.

    ERIC Educational Resources Information Center

    Organisation for Economic Cooperation and Development, Paris (France).

    This study of the development of international data networks, a phenomena of the 1970's, and policy issues arising from their use is an in depth investigation of 24 private and six public European networks commissioned from Logica Limited and sponsored by the governments of France, Germany, the Netherlands, Norway, Spain, and Sweden. The report…

  2. Mapping Efficient Communication Networks in Higher Education.

    ERIC Educational Resources Information Center

    Lubinescu, E. S.; Prabhu, R. P.; Terheggen, S. L.

    Some perspectives are presented that help explain communication networks in institutions of higher education and the factors that impede or facilitate their efficient functioning. The first theory that informs this exploration is that of K. Wieck (1969), which states that communication can be viewed through the lens of "sensemaking." The…

  3. Social Network Analysis and Mining to Monitor and Identify Problems with Large-Scale Information and Communication Technology Interventions

    PubMed Central

    da Silva, Aleksandra do Socorro; de Brito, Silvana Rossy; Vijaykumar, Nandamudi Lankalapalli; da Rocha, Cláudio Alex Jorge; Monteiro, Maurílio de Abreu; Costa, João Crisóstomo Weyl Albuquerque; Francês, Carlos Renato Lisboa

    2016-01-01

    The published literature reveals several arguments concerning the strategic importance of information and communication technology (ICT) interventions for developing countries where the digital divide is a challenge. Large-scale ICT interventions can be an option for countries whose regions, both urban and rural, present a high number of digitally excluded people. Our goal was to monitor and identify problems in interventions aimed at certification for a large number of participants in different geographical regions. Our case study is the training at the Telecentros.BR, a program created in Brazil to install telecenters and certify individuals to use ICT resources. We propose an approach that applies social network analysis and mining techniques to data collected from Telecentros.BR dataset and from the socioeconomics and telecommunications infrastructure indicators of the participants’ municipalities. We found that (i) the analysis of interactions in different time periods reflects the objectives of each phase of training, highlighting the increased density in the phase in which participants develop and disseminate their projects; (ii) analysis according to the roles of participants (i.e., tutors or community members) reveals that the interactions were influenced by the center (or region) to which the participant belongs (that is, a community contained mainly members of the same region and always with the presence of tutors, contradicting expectations of the training project, which aimed for intense collaboration of the participants, regardless of the geographic region); (iii) the social network of participants influences the success of the training: that is, given evidence that the degree of the community member is in the highest range, the probability of this individual concluding the training is 0.689; (iv) the North region presented the lowest probability of participant certification, whereas the Northeast, which served municipalities with similar

  4. Social Network Analysis and Mining to Monitor and Identify Problems with Large-Scale Information and Communication Technology Interventions.

    PubMed

    da Silva, Aleksandra do Socorro; de Brito, Silvana Rossy; Vijaykumar, Nandamudi Lankalapalli; da Rocha, Cláudio Alex Jorge; Monteiro, Maurílio de Abreu; Costa, João Crisóstomo Weyl Albuquerque; Francês, Carlos Renato Lisboa

    2016-01-01

    The published literature reveals several arguments concerning the strategic importance of information and communication technology (ICT) interventions for developing countries where the digital divide is a challenge. Large-scale ICT interventions can be an option for countries whose regions, both urban and rural, present a high number of digitally excluded people. Our goal was to monitor and identify problems in interventions aimed at certification for a large number of participants in different geographical regions. Our case study is the training at the Telecentros.BR, a program created in Brazil to install telecenters and certify individuals to use ICT resources. We propose an approach that applies social network analysis and mining techniques to data collected from Telecentros.BR dataset and from the socioeconomics and telecommunications infrastructure indicators of the participants' municipalities. We found that (i) the analysis of interactions in different time periods reflects the objectives of each phase of training, highlighting the increased density in the phase in which participants develop and disseminate their projects; (ii) analysis according to the roles of participants (i.e., tutors or community members) reveals that the interactions were influenced by the center (or region) to which the participant belongs (that is, a community contained mainly members of the same region and always with the presence of tutors, contradicting expectations of the training project, which aimed for intense collaboration of the participants, regardless of the geographic region); (iii) the social network of participants influences the success of the training: that is, given evidence that the degree of the community member is in the highest range, the probability of this individual concluding the training is 0.689; (iv) the North region presented the lowest probability of participant certification, whereas the Northeast, which served municipalities with similar

  5. Switch for serial or parallel communication networks

    DOEpatents

    Crosette, D.B.

    1994-07-19

    A communication switch apparatus and a method for use in a geographically extensive serial, parallel or hybrid communication network linking a multi-processor or parallel processing system has a very low software processing overhead in order to accommodate random burst of high density data. Associated with each processor is a communication switch. A data source and a data destination, a sensor suite or robot for example, may also be associated with a switch. The configuration of the switches in the network are coordinated through a master processor node and depends on the operational phase of the multi-processor network: data acquisition, data processing, and data exchange. The master processor node passes information on the state to be assumed by each switch to the processor node associated with the switch. The processor node then operates a series of multi-state switches internal to each communication switch. The communication switch does not parse and interpret communication protocol and message routing information. During a data acquisition phase, the communication switch couples sensors producing data to the processor node associated with the switch, to a downlink destination on the communications network, or to both. It also may couple an uplink data source to its processor node. During the data exchange phase, the switch couples its processor node or an uplink data source to a downlink destination (which may include a processor node or a robot), or couples an uplink source to its processor node and its processor node to a downlink destination. 9 figs.

  6. Switch for serial or parallel communication networks

    DOEpatents

    Crosette, Dario B.

    1994-01-01

    A communication switch apparatus and a method for use in a geographically extensive serial, parallel or hybrid communication network linking a multi-processor or parallel processing system has a very low software processing overhead in order to accommodate random burst of high density data. Associated with each processor is a communication switch. A data source and a data destination, a sensor suite or robot for example, may also be associated with a switch. The configuration of the switches in the network are coordinated through a master processor node and depends on the operational phase of the multi-processor network: data acquisition, data processing, and data exchange. The master processor node passes information on the state to be assumed by each switch to the processor node associated with the switch. The processor node then operates a series of multi-state switches internal to each communication switch. The communication switch does not parse and interpret communication protocol and message routing information. During a data acquisition phase, the communication switch couples sensors producing data to the processor node associated with the switch, to a downlink destination on the communications network, or to both. It also may couple an uplink data source to its processor node. During the data exchange phase, the switch couples its processor node or an uplink data source to a downlink destination (which may include a processor node or a robot), or couples an uplink source to its processor node and its processor node to a downlink destination.

  7. Informal Communication Among Scientists in Sleep Research

    ERIC Educational Resources Information Center

    Crawford, Susan

    1971-01-01

    Using sociometric techniques, an informal communication network is identified which includes 73 percent of the scientists. Information transferred to these scientists is so situated that it could be transmitted to 95 percent of the network scientists through one intermediary scientist or less. (23 references) (Author)

  8. Space Communications Networks Support MMS

    NASA Video Gallery

    All three of NASA’s Space Communications Networks are excited to support the Magnetospheric Multiscale (MMS) Mission in its journey to study the microphysics of magnetic reconnection. The Near Eart...

  9. Information Horizons in Complex Networks

    NASA Astrophysics Data System (ADS)

    Sneppen, Kim

    2005-03-01

    We investigate how the structure constrain specific communication in social-, man-made and biological networks. We find that human networks of governance and collaboration are predictable on teat-a-teat level, reflecting well defined pathways, but globally inefficient (1). In contrast, the Internet tends to have better overall communication abilities, more alternative pathways, and is therefore more robust. Between these extremes are the molecular network of living organisms. Further, for most real world networks we find that communication ability is favored by topology on small distances, but disfavored at larger distances (2,3,4). We discuss the topological implications in terms of modularity and the positioning of hubs in the networks (5,6). Finally we introduce some simple models which demonstarte how communication may shape the structure of in particular man made networks (7,8). 1) K. Sneppen, A. Trusina, M. Rosvall (2004). Hide and seek on complex networks [cond-mat/0407055] 2) M. Rosvall, A. Trusina, P. Minnhagen and K. Sneppen (2004). Networks and Cities: An Information Perspective [cond-mat/0407054]. In PRL. 3) A. Trusina, M. Rosvall, K. Sneppen (2004). Information Horizons in Networks. [cond-mat/0412064] 4) M. Rosvall, P. Minnhagen, K. Sneppen (2004). Navigating Networks with Limited Information. [cond-mat/0412051] 5) S. Maslov and K. Sneppen (2002). Specificity and stability in topology of protein networks Science 296, 910-913 [cond-mat/0205380]. 6) A. Trusina, S. Maslov, P. Minnhagen, K. Sneppen Hierarchy Measures in Complex Networks. Phys. Rev. Lett. 92, 178702 [cond-mat/0308339]. 7) M. Rosvall and K. Sneppen (2003). Modeling Dynamics of Information Networks. Phys. Rev. Lett. 91, 178701 [cond-mat/0308399]. 8) B-J. Kim, A. Trusina, P. Minnhagen, K. Sneppen (2003). Self Organized Scale-Free Networks from Merging and Regeneration. nlin.AO/0403006. In European Journal of Physics.

  10. Measurement of Computer Communication Networks.

    ERIC Educational Resources Information Center

    Abrams, Marshall D.; And Others

    Measures, tools, and techniques applicable to the performance measurement of computer communication networks are described for technicians who procure computer services from a remote access network. Cost considerations are discussed as a major component of evaluation, and measurement and evaluation methodologies are surveyed. External measurement…

  11. Information and communication technology

    NASA Technical Reports Server (NTRS)

    Edelson, Burton I.; Pelton, Joseph N.; Bostian, Charles W.; Brandon, William T.; Chan, Vincent W. S.; Hager, E. Paul; Helm, Neil R.; Jennings, Raymond D.; Kwan, Robert K.; Mahle, Christoph E.

    1994-01-01

    NASA and the National Science Foundation (NSF) commissioned a panel of U.S. experts to study the international status of satellite communications systems and technology. The study covers emerging systems concepts, applications, services, and the attendant technologies. The panel members traveled to Europe, Japan, and Russia to gather information firsthand. They visited 17 sites in Europe, 20 in Japan, and 4 in Russia. These included major manufacturers, government organizations, service providers, and associated research and development facilities. The panel's report was reviewed by the sites visited, by the panel, and by representatives of U.S. industry. The report details the information collected and compares it to U.S. activities.

  12. A Communications Network Architecture for Future Mars Missions

    NASA Astrophysics Data System (ADS)

    Gilstrap, R.; Alena, R.; Stone, T.

    2012-06-01

    We propose a Mars communications network architecture incorporating the Internet Protocol, small communications relay satellites, laser communications, delay tolerant networking, mobile ad hoc networking, and wireless sensor networks.

  13. Communication Dynamics in Finite Capacity Social Networks

    NASA Astrophysics Data System (ADS)

    Haerter, Jan O.; Jamtveit, Bjørn; Mathiesen, Joachim

    2012-10-01

    In communication networks, structure and dynamics are tightly coupled. The structure controls the flow of information and is itself shaped by the dynamical process of information exchanged between nodes. In order to reconcile structure and dynamics, a generic model, based on the local interaction between nodes, is considered for the communication in large social networks. In agreement with data from a large human organization, we show that the flow is non-Markovian and controlled by the temporal limitations of individuals. We confirm the versatility of our model by predicting simultaneously the degree-dependent node activity, the balance between information input and output of nodes, and the degree distribution. Finally, we quantify the limitations to network analysis when it is based on data sampled over a finite period of time.

  14. NASA Integrated Space Communications Network

    NASA Technical Reports Server (NTRS)

    Tai, Wallace; Wright, Nate; Prior, Mike; Bhasin, Kul

    2012-01-01

    The NASA Integrated Network for Space Communications and Navigation (SCaN) has been in the definition phase since 2010. It is intended to integrate NASA s three existing network elements, i.e., the Space Network, Near Earth Network, and Deep Space Network, into a single network. In addition to the technical merits, the primary purpose of the Integrated Network is to achieve a level of operating cost efficiency significantly higher than it is today. Salient features of the Integrated Network include (a) a central system element that performs service management functions and user mission interfaces for service requests; (b) a set of common service execution equipment deployed at the all stations that provides return, forward, and radiometric data processing and delivery capabilities; (c) the network monitor and control operations for the entire integrated network are conducted remotely and centrally at a prime-shift site and rotating among three sites globally (a follow-the-sun approach); (d) the common network monitor and control software deployed at all three network elements that supports the follow-the-sun operations.

  15. Underwater optical wireless communication network

    NASA Astrophysics Data System (ADS)

    Arnon, Shlomi

    2010-01-01

    The growing need for underwater observation and subsea monitoring systems has stimulated considerable interest in advancing the enabling technologies of underwater wireless communication and underwater sensor networks. This communication technology is expected to play an important role in investigating climate change, in monitoring biological, biogeochemical, evolutionary, and ecological changes in the sea, ocean, and lake environments, and in helping to control and maintain oil production facilities and harbors using unmanned underwater vehicles (UUVs), submarines, ships, buoys, and divers. However, the present technology of underwater acoustic communication cannot provide the high data rate required to investigate and monitor these environments and facilities. Optical wireless communication has been proposed as the best alternative to meet this challenge. Models are presented for three kinds of optical wireless communication links: (a) a line-of-sight link, (b) a modulating retroreflector link, and (c) a reflective link, all of which can provide the required data rate. We analyze the link performance based on these models. From the analysis, it is clear that as the water absorption increases, the communication performance decreases dramatically for the three link types. However, by using the scattered light it was possible to mitigate this decrease in some cases. It is concluded from the analysis that a high-data-rate underwater optical wireless network is a feasible solution for emerging applications such as UUV-to-UUV links and networks of sensors, and extended ranges in these applications could be achieved by applying a multi-hop concept.

  16. Congenital Heart Information Network

    MedlinePlus

    ... heart defects. Important Notice The Congenital Heart Information Network website is temporarily out of service. Please join ... and Uwe Baemayr for The Congenital Heart Information Network Exempt organization under Section 501(c)3. Copyright © ...

  17. Multiple-Ring Digital Communication Network

    NASA Technical Reports Server (NTRS)

    Kirkham, Harold

    1992-01-01

    Optical-fiber digital communication network to support data-acquisition and control functions of electric-power-distribution networks. Optical-fiber links of communication network follow power-distribution routes. Since fiber crosses open power switches, communication network includes multiple interconnected loops with occasional spurs. At each intersection node is needed. Nodes of communication network include power-distribution substations and power-controlling units. In addition to serving data acquisition and control functions, each node acts as repeater, passing on messages to next node(s). Multiple-ring communication network operates on new AbNET protocol and features fiber-optic communication.

  18. Data communication network at the ASRM facility

    NASA Technical Reports Server (NTRS)

    Moorhead, Robert J., II; Smith, Wayne D.

    1993-01-01

    This report describes the simulation of the overall communication network structure for the Advanced Solid Rocket Motor (ASRM) facility being built at Yellow Creek near Iuka, Mississippi as of today. The report is compiled using information received from NASA/MSFC, LMSC, AAD, and RUST Inc. As per the information gathered, the overall network structure will have one logical FDDI ring acting as a backbone for the whole complex. The buildings will be grouped into two categories viz. manufacturing intensive and manufacturing non-intensive. The manufacturing intensive buildings will be connected via FDDI to the Operational Information System (OIS) in the main computing center in B_1000. The manufacturing non-intensive buildings will be connected by 10BASE-FL to the OIS through the Business Information System (BIS) hub in the main computing center. All the devices inside B_1000 will communicate with the BIS. The workcells will be connected to the Area Supervisory Computers (ASCs) through the nearest manufacturing intensive hub and one of the OIS hubs. Comdisco's Block Oriented Network Simulator (BONeS) has been used to simulate the performance of the network. BONeS models a network topology, traffic, data structures, and protocol functions using a graphical interface. The main aim of the simulations was to evaluate the loading of the OIS, the BIS, and the ASCs, and the network links by the traffic generated by the workstations and workcells throughout the site.

  19. Network-Centric Quantum Communications

    NASA Astrophysics Data System (ADS)

    Hughes, Richard

    2014-03-01

    Single-photon quantum communications (QC) offers ``future-proof'' cryptographic security rooted in the laws of physics. Today's quantum-secured communications cannot be compromised by unanticipated future technological advances. But to date, QC has only existed in point-to-point instantiations that have limited ability to address the cyber security challenges of our increasingly networked world. In my talk I will describe a fundamentally new paradigm of network-centric quantum communications (NQC) that leverages the network to bring scalable, QC-based security to user groups that may have no direct user-to-user QC connectivity. With QC links only between each of N users and a trusted network node, NQC brings quantum security to N2 user pairs, and to multi-user groups. I will describe a novel integrated photonics quantum smartcard (``QKarD'') and its operation in a multi-node NQC test bed. The QKarDs are used to implement the quantum cryptographic protocols of quantum identification, quantum key distribution and quantum secret splitting. I will explain how these cryptographic primitives are used to provide key management for encryption, authentication, and non-repudiation for user-to-user communications. My talk will conclude with a description of a recent demonstration that QC can meet both the security and quality-of-service (latency) requirements for electric grid control commands and data. These requirements cannot be met simultaneously with present-day cryptography.

  20. Research Networks and Libraries. Applications and Issues for a Global Information Network. UDT Series on Data Communication Technologies and Standards for Libraries, Report #1.

    ERIC Educational Resources Information Center

    Cleveland, Gary

    This paper is intended to provide interested librarians with a basic knowledge of research networks (as opposed to library networks), focusing specifically on the manner in which they can be used by the international library community to support library functions and improve access to bibliographic information, as well as the technical and policy…

  1. Dynamic information routing in complex networks

    PubMed Central

    Kirst, Christoph; Timme, Marc; Battaglia, Demian

    2016-01-01

    Flexible information routing fundamentally underlies the function of many biological and artificial networks. Yet, how such systems may specifically communicate and dynamically route information is not well understood. Here we identify a generic mechanism to route information on top of collective dynamical reference states in complex networks. Switching between collective dynamics induces flexible reorganization of information sharing and routing patterns, as quantified by delayed mutual information and transfer entropy measures between activities of a network's units. We demonstrate the power of this mechanism specifically for oscillatory dynamics and analyse how individual unit properties, the network topology and external inputs co-act to systematically organize information routing. For multi-scale, modular architectures, we resolve routing patterns at all levels. Interestingly, local interventions within one sub-network may remotely determine nonlocal network-wide communication. These results help understanding and designing information routing patterns across systems where collective dynamics co-occurs with a communication function. PMID:27067257

  2. Dynamic information routing in complex networks.

    PubMed

    Kirst, Christoph; Timme, Marc; Battaglia, Demian

    2016-01-01

    Flexible information routing fundamentally underlies the function of many biological and artificial networks. Yet, how such systems may specifically communicate and dynamically route information is not well understood. Here we identify a generic mechanism to route information on top of collective dynamical reference states in complex networks. Switching between collective dynamics induces flexible reorganization of information sharing and routing patterns, as quantified by delayed mutual information and transfer entropy measures between activities of a network's units. We demonstrate the power of this mechanism specifically for oscillatory dynamics and analyse how individual unit properties, the network topology and external inputs co-act to systematically organize information routing. For multi-scale, modular architectures, we resolve routing patterns at all levels. Interestingly, local interventions within one sub-network may remotely determine nonlocal network-wide communication. These results help understanding and designing information routing patterns across systems where collective dynamics co-occurs with a communication function. PMID:27067257

  3. Dynamic information routing in complex networks

    NASA Astrophysics Data System (ADS)

    Kirst, Christoph; Timme, Marc; Battaglia, Demian

    2016-04-01

    Flexible information routing fundamentally underlies the function of many biological and artificial networks. Yet, how such systems may specifically communicate and dynamically route information is not well understood. Here we identify a generic mechanism to route information on top of collective dynamical reference states in complex networks. Switching between collective dynamics induces flexible reorganization of information sharing and routing patterns, as quantified by delayed mutual information and transfer entropy measures between activities of a network's units. We demonstrate the power of this mechanism specifically for oscillatory dynamics and analyse how individual unit properties, the network topology and external inputs co-act to systematically organize information routing. For multi-scale, modular architectures, we resolve routing patterns at all levels. Interestingly, local interventions within one sub-network may remotely determine nonlocal network-wide communication. These results help understanding and designing information routing patterns across systems where collective dynamics co-occurs with a communication function.

  4. Communications for unattended sensor networks

    NASA Astrophysics Data System (ADS)

    Nemeroff, Jay L.; Angelini, Paul; Orpilla, Mont; Garcia, Luis; DiPierro, Stefano

    2004-07-01

    The future model of the US Army's Future Combat Systems (FCS) and the Future Force reflects a combat force that utilizes lighter armor protection than the current standard. Survival on the future battlefield will be increased by the use of advanced situational awareness provided by unattended tactical and urban sensors that detect, identify, and track enemy targets and threats. Successful implementation of these critical sensor fields requires the development of advanced sensors, sensor and data-fusion processors, and a specialized communications network. To ensure warfighter and asset survivability, the communications must be capable of near real-time dissemination of the sensor data using robust, secure, stealthy, and jam resistant links so that the proper and decisive action can be taken. Communications will be provided to a wide-array of mission-specific sensors that are capable of processing data from acoustic, magnetic, seismic, and/or Chemical, Biological, Radiological, and Nuclear (CBRN) sensors. Other, more powerful, sensor node configurations will be capable of fusing sensor data and intelligently collect and process data images from infrared or visual imaging cameras. The radio waveform and networking protocols being developed under the Soldier Level Integrated Communications Environment (SLICE) Soldier Radio Waveform (SRW) and the Networked Sensors for the Future Force Advanced Technology Demonstration are part of an effort to develop a common waveform family which will operate across multiple tactical domains including dismounted soldiers, ground sensor, munitions, missiles and robotics. These waveform technologies will ultimately be transitioned to the JTRS library, specifically the Cluster 5 requirement.

  5. [Sensitization: information, education and communication].

    PubMed

    1993-01-01

    IEC programs increase the knowledge and motivation of decision makers with power over determinants of population growth and socioeconomic development. Information may improve the awareness of public and private officials of population questions and of the form in which they are treated. Information activities involve demographic growth and spatial distribution of the population, the demographic and health benefits of family planning, and the danger of sexually transmitted diseases and AIDS. The mass media are the main source of information, but in developing countries various forms of folk media enjoyed by the public may also be used. Technical journals and other information networks are available for the professional audience. Population communication promotes acceptance and use of family planning. Radio and television series that incorporate family planning themes, popular music that mentions population problems, and broadcasts of telephone question and answer programs have been influential in some countries. Such informational programs may be very important in regions with low levels of literacy. Programs targeted to adolescents may help resolve problems of early pregnancy. More than 80 countries include population education in their school curriculum. The objectives vary, but they generally include making students aware of population problems and of their own responsibilities. Population questions are also included in many professional training programs. PMID:12289051

  6. An implementation of Software Defined Radios for federated aerospace networks: Informing satellite implementations using an inter-balloon communications experiment

    NASA Astrophysics Data System (ADS)

    Akhtyamov, Rustam; Cruz, Ignasi Lluch i.; Matevosyan, Hripsime; Knoll, Dominik; Pica, Udrivolf; Lisi, Marco; Golkar, Alessandro

    2016-06-01

    Novel space mission concepts such as Federated Satellite Systems promise to enhance sustainability, robustness, and reliability of current missions by means of in-orbit sharing of space assets. This new paradigm requires the utilization of several technologies in order to confer flexibility and re-configurability to communications systems among heterogeneous spacecrafts. This paper illustrates the results of the experimental demonstration of the value proposition of federated satellites through two stratospheric balloons interoperating with a tracking ground station through Commercial Off-The-Shelf Software Defined Radios (SDRs). The paper reports telemetry analysis and characterizes the communications network that was realized in-flight. Furthermore, it provides details on an in-flight anomaly experienced by one of the balloons, which was recovered through the use of the federated technology that has been developed. The anomaly experienced led to the early loss of the directional link from the ground station to the affected stratospheric balloon node after 15 min in flight. Nevertheless, thanks to the federated approach among the systems, the ground station was still able to retrieve the balloon's data in real time through the network system, for which the other balloon operated as a federated relay for 45 min in flight, uninterrupted. In other words, the federated approach to the system allowed triplicating the useful lifetime of the defective system, which would have not been possible to realize otherwise. Such anomaly coincidentally demonstrated the value of the federated approach to space systems design. The paper paves the way for future tests on space assets.

  7. Communication devices for network-hopping communications and methods of network-hopping communications

    DOEpatents

    Buttles, John W.

    2011-12-20

    Wireless communication devices include a software-defined radio coupled to processing circuitry. The processing circuitry is configured to execute computer programming code. Storage media is coupled to the processing circuitry and includes computer programming code configured to cause the processing circuitry to configure and reconfigure the software-defined radio to operate on each of a plurality of communication networks according to a selected sequence. Methods for communicating with a wireless device and methods of wireless network-hopping are also disclosed.

  8. Communication devices for network-hopping communications and methods of network-hopping communications

    DOEpatents

    Buttles, John W

    2013-04-23

    Wireless communication devices include a software-defined radio coupled to processing circuitry. The system controller is configured to execute computer programming code. Storage media is coupled to the system controller and includes computer programming code configured to cause the system controller to configure and reconfigure the software-defined radio to operate on each of a plurality of communication networks according to a selected sequence. Methods for communicating with a wireless device and methods of wireless network-hopping are also disclosed.

  9. Data communication network at the ASRM facility

    NASA Technical Reports Server (NTRS)

    Moorhead, Robert J., III; Smith, Wayne D.; Nirgudkar, Ravi; Dement, James

    1994-01-01

    This three-year project (February 1991 to February 1994) has involved analyzing and helping to design the communication network for the Advanced Solid Rocket Motor (ASRM) facility at Yellow Creek, near Iuka, MS. The principal concerns in the analysis were the bandwidth (both on average and in the worst case) and the expandability of the network. As the communication network was designed and modified, a careful evaluation of the bandwidth of the network, the capabilities of the protocol, and the requirements of the controllers and computers on the network was required. The overall network, which was heterogeneous in protocol and bandwidth, needed to be modeled, analyzed, and simulated to obtain some degree of confidence in its performance capabilities and in its performance under nominal and heavy loads. The results of our analysis did have an impact on the design and operation of the ASRM facility. During 1993 we analyzed many configurations of this basic network structure. The analyses are described in detail in Section 2 and 3 herein. Section 2 reports on an analysis of the whole network. The preliminary results of that research indicated that the most likely bottleneck as the network traffic increased would be the hubs. Thus a study of Cabletron hubs was initiated. The results of that study are in Section 3. Section 4 herein reports on the final network configuration analyzed. When the ASRM facility was mothballed in December of 1993, this was basically the planned and partially installed network. A briefing was held at NASA/MSFC on December 7, 1993, at which time our final analysis and conclusions were disseminated. This report contains a written record of most of the information disseminated at that briefing.

  10. Data communication network at the ASRM facility

    NASA Technical Reports Server (NTRS)

    Moorhead, Robert J., II; Smith, Wayne D.; Nirgudkar, Ravi; Zhu, Zhifan; Robinson, Walter

    1993-01-01

    The main objective of the report is to present the overall communication network structure for the Advanced Solid Rocket Motor (ASRM) facility being built at Yellow Creek near Iuka, Mississippi. This report is compiled using information received from NASA/MSFC, LMSC, AAD, and RUST Inc. As per the information gathered, the overall network structure will have one logical FDDI ring acting as a backbone for the whole complex. The buildings will be grouped into two categories viz. manufacturing critical and manufacturing non-critical. The manufacturing critical buildings will be connected via FDDI to the Operational Information System (OIS) in the main computing center in B 1000. The manufacturing non-critical buildings will be connected by 10BASE-FL to the Business Information System (BIS) in the main computing center. The workcells will be connected to the Area Supervisory Computers (ASCs) through the nearest manufacturing critical hub and one of the OIS hubs. The network structure described in this report will be the basis for simulations to be carried out next year. The Comdisco's Block Oriented Network Simulator (BONeS) will be used for the network simulation. The main aim of the simulations will be to evaluate the loading of the OIS, the BIS, the ASCs, and the network links by the traffic generated by the workstations and workcells throughout the site.

  11. Communication security in open health care networks.

    PubMed

    Blobel, B; Pharow, P; Engel, K; Spiegel, V; Krohn, R

    1999-01-01

    Fulfilling the shared care paradigm, health care networks providing open systems' interoperability in health care are needed. Such communicating and co-operating health information systems, dealing with sensitive personal medical information across organisational, regional, national or even international boundaries, require appropriate security solutions. Based on the generic security model, within the European MEDSEC project an open approach for secure EDI like HL7, EDIFACT, XDT or XML has been developed. The consideration includes both securing the message in an unsecure network and the transport of the unprotected information via secure channels (SSL, TLS etc.). Regarding EDI, an open and widely usable security solution has been specified and practically implemented for the examples of secure mailing and secure file transfer (FTP) via wrapping the sensitive information expressed by the corresponding protocols. The results are currently prepared for standardisation. PMID:10724890

  12. Communication complexity and information complexity

    NASA Astrophysics Data System (ADS)

    Pankratov, Denis

    Information complexity enables the use of information-theoretic tools in communication complexity theory. Prior to the results presented in this thesis, information complexity was mainly used for proving lower bounds and direct-sum theorems in the setting of communication complexity. We present three results that demonstrate new connections between information complexity and communication complexity. In the first contribution we thoroughly study the information complexity of the smallest nontrivial two-party function: the AND function. While computing the communication complexity of AND is trivial, computing its exact information complexity presents a major technical challenge. In overcoming this challenge, we reveal that information complexity gives rise to rich geometrical structures. Our analysis of information complexity relies on new analytic techniques and new characterizations of communication protocols. We also uncover a connection of information complexity to the theory of elliptic partial differential equations. Once we compute the exact information complexity of AND, we can compute exact communication complexity of several related functions on n-bit inputs with some additional technical work. Previous combinatorial and algebraic techniques could only prove bounds of the form theta( n). Interestingly, this level of precision is typical in the area of information theory, so our result demonstrates that this meta-property of precise bounds carries over to information complexity and in certain cases even to communication complexity. Our result does not only strengthen the lower bound on communication complexity of disjointness by making it more exact, but it also shows that information complexity provides the exact upper bound on communication complexity. In fact, this result is more general and applies to a whole class of communication problems. In the second contribution, we use self-reduction methods to prove strong lower bounds on the information

  13. Communication through resonance in spiking neuronal networks.

    PubMed

    Hahn, Gerald; Bujan, Alejandro F; Frégnac, Yves; Aertsen, Ad; Kumar, Arvind

    2014-08-01

    The cortex processes stimuli through a distributed network of specialized brain areas. This processing requires mechanisms that can route neuronal activity across weakly connected cortical regions. Routing models proposed thus far are either limited to propagation of spiking activity across strongly connected networks or require distinct mechanisms that create local oscillations and establish their coherence between distant cortical areas. Here, we propose a novel mechanism which explains how synchronous spiking activity propagates across weakly connected brain areas supported by oscillations. In our model, oscillatory activity unleashes network resonance that amplifies feeble synchronous signals and promotes their propagation along weak connections ("communication through resonance"). The emergence of coherent oscillations is a natural consequence of synchronous activity propagation and therefore the assumption of different mechanisms that create oscillations and provide coherence is not necessary. Moreover, the phase-locking of oscillations is a side effect of communication rather than its requirement. Finally, we show how the state of ongoing activity could affect the communication through resonance and propose that modulations of the ongoing activity state could influence information processing in distributed cortical networks. PMID:25165853

  14. Reinforced communication and social navigation generate groups in model networks.

    PubMed

    Rosvall, M; Sneppen, K

    2009-02-01

    To investigate the role of information flow in group formation, we introduce a model of communication and social navigation. We let agents gather information in an idealized network society and demonstrate that heterogeneous groups can evolve without presuming that individuals have different interests. In our scenario, individuals' access to global information is constrained by local communication with the nearest neighbors on a dynamic network. The result is reinforced interests among like-minded agents in modular networks; the flow of information works as a glue that keeps individuals together. The model explains group formation in terms of limited information access and highlights global broadcasting of information as a way to counterbalance this fragmentation. To illustrate how the information constraints imposed by the communication structure affects future development of real-world systems, we extrapolate dynamics from the topology of four social networks. PMID:19391810

  15. Information efficiency in visual communication

    NASA Technical Reports Server (NTRS)

    Alter-Gartenberg, Rachel; Rahman, Zia-Ur

    1993-01-01

    This paper evaluates the quantization process in the context of the end-to-end performance of the visual-communication channel. Results show that the trade-off between data transmission and visual quality revolves around the information in the acquired signal, not around its energy. Improved information efficiency is gained by frequency dependent quantization that maintains the information capacity of the channel and reduces the entropy of the encoded signal. Restorations with energy bit-allocation lose both in sharpness and clarity relative to restorations with information bit-allocation. Thus, quantization with information bit-allocation is preferred for high information efficiency and visual quality in optimized visual communication.

  16. PIPELINES AS COMMUNICATION NETWORK LINKS

    SciTech Connect

    Kelvin T. Erickson; Ann Miller; E. Keith Stanek; C.H. Wu; Shari Dunn-Norman

    2005-03-14

    This report presents the results of an investigation into two methods of using the natural gas pipeline as a communication medium. The work addressed the need to develop secure system monitoring and control techniques between the field and control centers and to robotic devices in the pipeline. In the first method, the pipeline was treated as a microwave waveguide. In the second method, the pipe was treated as a leaky feeder or a multi-ground neutral and the signal was directly injected onto the metal pipe. These methods were tested on existing pipeline loops at UMR and Batelle. The results reported in this report indicate the feasibility of both methods. In addition, a few suitable communication link protocols for this network were analyzed.

  17. Rural Information Network.

    ERIC Educational Resources Information Center

    National Public Telecomputing Network, Cleveland, OH.

    This report describes the National Public Telecomputing Network's (NPTN) development of free, public-access, community computer systems throughout the United States. It also provides information on how to initiate a "Free-Net" through the Rural Information Network. Free-Nets are multi-user systems with some of the power and sophistication of…

  18. PESTICIDE INFORMATION NETWORK

    EPA Science Inventory

    The Pesticide Information Network (PIN) is an interactive database containing information about pesticides. PIN is a free service offered by the USEPAs Office of Pesticide Programs which provides contacts on pesticide issues, has a bulletin board network for public and private us...

  19. A vision of network-centric military communications

    NASA Astrophysics Data System (ADS)

    Conklin, Ross, Jr.; Burbank, Jack; Nichols, Robert, Jr.

    2005-05-01

    This paper presents a vision for a future capability-based military communications system that considers user requirements. Historically, the military has developed and fielded many specialized communications systems. While these systems solved immediate communications problems, they were not designed to operate with other systems. As information has become more important to the execution of war, the "stove-pipe" nature of the communications systems deployed by the military is no longer acceptable. Realizing this, the military has begun the transformation of communications to a network-centric communications paradigm. However, the specialized communications systems were developed in response to the widely varying environments related to military communications. These environments, and the necessity for effective communications within these environments, do not disappear under the network-centric paradigm. In fact, network-centric communications allows for one message to cross many of these environments by transiting multiple networks. The military would also like one communications approach that is capable of working well in multiple environments. This paper presents preliminary work on the creation of a framework that allows for a reconfigurable device that is capable of adapting to the physical and network environments. The framework returns to the Open Systems Interconnect (OSI) architecture with the addition of a standardized intra-layer control interface for control information exchange, a standardized data interface and a proposed device architecture based on the software radio.

  20. Computing, Information and Communications Technology (CICT) Website

    NASA Technical Reports Server (NTRS)

    Hardman, John; Tu, Eugene (Technical Monitor)

    2002-01-01

    The Computing, Information and Communications Technology Program (CICT) was established in 2001 to ensure NASA's Continuing leadership in emerging technologies. It is a coordinated, Agency-wide effort to develop and deploy key enabling technologies for a broad range of mission-critical tasks. The NASA CICT program is designed to address Agency-specific computing, information, and communications technology requirements beyond the projected capabilities of commercially available solutions. The areas of technical focus have been chosen for their impact on NASA's missions, their national importance, and the technical challenge they provide to the Program. In order to meet its objectives, the CICT Program is organized into the following four technology focused projects: 1) Computing, Networking and Information Systems (CNIS); 2) Intelligent Systems (IS); 3) Space Communications (SC); 4) Information Technology Strategic Research (ITSR).

  1. Information Gap in Communicative Classrooms.

    ERIC Educational Resources Information Center

    Liao, Xiaoqing

    In traditional, grammar-oriented second language classrooms, the most common classroom procedure is for the teacher to ask the student a question for which the answer is already known to both. Because no real information is exchanged, this is not a communicative practice. It is alien to the real communicative needs of students, involves no…

  2. Modeling information flow in biological networks

    NASA Astrophysics Data System (ADS)

    Kim, Yoo-Ah; Przytycki, Jozef H.; Wuchty, Stefan; Przytycka, Teresa M.

    2011-06-01

    Large-scale molecular interaction networks are being increasingly used to provide a system level view of cellular processes. Modeling communications between nodes in such huge networks as information flows is useful for dissecting dynamical dependences between individual network components. In the information flow model, individual nodes are assumed to communicate with each other by propagating the signals through intermediate nodes in the network. In this paper, we first provide an overview of the state of the art of research in the network analysis based on information flow models. In the second part, we describe our computational method underlying our recent work on discovering dysregulated pathways in glioma. Motivated by applications to inferring information flow from genotype to phenotype in a very large human interaction network, we generalized previous approaches to compute information flows for a large number of instances and also provided a formal proof for the method.

  3. Critical size of ego communication networks

    NASA Astrophysics Data System (ADS)

    Wang, Qing; Gao, Jian; Zhou, Tao; Hu, Zheng; Tian, Hui

    2016-06-01

    With the help of information and communication technologies, studies on the overall social networks have been extensively reported recently. However, investigations on the directed Ego Communication Networks (ECNs) remain insufficient, where an ECN stands for a sub network composed of a centralized individual and his/her direct contacts. In this paper, the directed ECNs are built on the Call Detail Records (CDRs), which cover more than 7 million people of a provincial capital city in China for half a year. Results show that there is a critical size for ECN at about 150, above which the average emotional closeness between ego and alters drops, the balanced relationship between ego and network collapses, and the proportion of strong ties decreases. This paper not only demonstrate the significance of ECN size in affecting its properties, but also shows accordance with the “Dunbar's Number”. These results can be viewed as a cross-culture supportive evidence to the well-known Social Brain Hypothesis (SBH).

  4. Communicability reveals a transition to coordinated behavior in multiplex networks

    NASA Astrophysics Data System (ADS)

    Estrada, Ernesto; Gómez-Gardeñes, Jesús

    2014-04-01

    We analyze the flow of information in multiplex networks by means of the communicability function. First, we generalize this measure from its definition from simple graphs to multiplex networks. Then, we study its relevance for the analysis of real-world systems by studying a social multiplex where information flows using formal-informal channels and an air transportation system where the layers represent different air companies. Accordingly, the communicability, which is essential for the good performance of these complex systems, emerges at a systemic operation point in the multiplex where the performance of the layers operates in a coordinated way very differently from the state represented by a collection of unconnected networks.

  5. Communicating risk information and warnings

    USGS Publications Warehouse

    Mileti, D. S.

    1990-01-01

    Major advances have occurred over the last 20 years about how to effectively communicate risk information and warnings to the public. These lessons have been hard won. Knowledge has mounted on the finding from social scientific studies of risk communication failures, successes and those which fell somewhere in between. Moreover, the last 2 decades have borne witness to the brith, cultivation, and blossoming of information sharing between those physical scientists who discover new information about risk and those communcation scientists who trace its diffusion and then measure pbulic reaction. 

  6. Analyzing Human Communication Networks in Organizations: Applications to Management Problems.

    ERIC Educational Resources Information Center

    Farace, Richard V.; Danowski, James A.

    Investigating the networks of communication in organizations leads to an understanding of efficient and inefficient information dissemination as practiced in large systems. Most important in organizational communication is the role of the "liaison person"--the coordinator of intercommunication. When functioning efficiently, coordinators maintain…

  7. The Sociotechnical Networks of Scholarly Communication.

    ERIC Educational Resources Information Center

    Beagle, Donald

    2001-01-01

    Discusses the state of flux in scholarly communications and publishing, explains the Actor-Network Theory that offers an interdisciplinary approach to understanding the impact on libraries, provides an overview of the evolution of scholarly communications sociotechnical networks, and analyzes the strategy of the Scholarly Publishing and Academic…

  8. Research Priorities in Networking and Communications.

    ERIC Educational Resources Information Center

    National Science Foundation, Washington, DC.

    A workshop focused on major research issues in networking and communications. This report defines the context for research priorities and initiatives and deals with issues in networking and communications. Fifteen major research priorities and four research specific initiatives were identified by participants as areas that should be pursued over…

  9. Structure and tie strengths in mobile communication networks.

    PubMed

    Onnela, J-P; Saramäki, J; Hyvönen, J; Szabó, G; Lazer, D; Kaski, K; Kertész, J; Barabási, A-L

    2007-05-01

    Electronic databases, from phone to e-mails logs, currently provide detailed records of human communication patterns, offering novel avenues to map and explore the structure of social and communication networks. Here we examine the communication patterns of millions of mobile phone users, allowing us to simultaneously study the local and the global structure of a society-wide communication network. We observe a coupling between interaction strengths and the network's local structure, with the counterintuitive consequence that social networks are robust to the removal of the strong ties but fall apart after a phase transition if the weak ties are removed. We show that this coupling significantly slows the diffusion process, resulting in dynamic trapping of information in communities and find that, when it comes to information diffusion, weak and strong ties are both simultaneously ineffective. PMID:17456605

  10. Effective Protocols for Mobile Communications and Networking

    SciTech Connect

    Espinoza, J.; Sholander, P.; Van Leeuwen, B,

    1998-12-01

    This report examines methods of mobile communications with an emphasis on mobile computing and wireless communications. Many of the advances in communications involve the use of Internet Protocol (IP), Asynchronous Transfer Mode (ATM), and ad hoc network protocols. However, many of the advances in these protocols have been focused on wired communications. Recently much focus has been directed at advancing communication technology in the area of mobile wireless networks. This report discusses various protocols used in mobile communications and proposes a number of extensions to existing protocols. A detailed discussion is also included on desirable protocol characteristics and evaluation criteria. In addition, the report includes a discussion on several network simulation tools that maybe used to evaluate network protocols.

  11. State energy information networks

    SciTech Connect

    Tatar, J.; Ettinger, G.; Wrabel, M.

    1984-06-01

    In November 1983, Argonne National Laboratory (ANL) initiated a study under the sponsorship of the US Department of Energy (DOE) State Programs Branch to examine state energy information networks. Goal was to help DOE decide how best to allocate resources to assist states in acquiring information related to state energy programs and policies.

  12. Weather Information Communications (WINCOMM) Overview and Status

    NASA Technical Reports Server (NTRS)

    Martzaklis, K.

    2003-01-01

    The second annual project review of Weather Information Communications (WINCOMM) is presented. The topics of discussion include: 1) In-Flight Weather Information; 2) System Elements; 3) Technology Investment Areas; 4) NAS Information Exchange; 5) FIS Datalink Architecture Analyses; 6) Hybrid FIS Datalink Architecture; 7) FIS Datalink Architecture Analyses; 8) Air Transport: Ground and Satellite-based Datalinks; 9) General Aviation: Ground and Satellite-based Datalinks; 10) Low Altitude AutoMET Reporting; 11) AutoMET: Airborne-based Datalinks; 12) Network Protocols Development; and 13) FAA/NASA Collaboration. A summary of WINCOMM is also included. This paper is in viewgraph form.

  13. Coding for spread-spectrum communications networks

    NASA Astrophysics Data System (ADS)

    Kim, Bal G.

    1987-03-01

    The multiple-access capability of a frequency-hopp packet radio network is investigated from a coding point of view. The achievable region of code rate and channel traffic and the normalized throughput are considered as performance measures. We model the communication system from the modulator input to the demodulator output as an I-user interference channel, and evaluate the asymptotic performance of various coding schemes for channels with perfect side information, no side information, and imperfect side information. The coding schemes being considered are Reed-Solomon codes, concatenated codes, and parallel decoding schemes. We derive the optimal code rate and the optimal channel traffic at which the normalized throughput is maximized, and from these optimum values the asymptotic maximum normalized throughput is derived. The results are then compared with channel capacities.

  14. Extracting association patterns in network communications.

    PubMed

    Portela, Javier; Villalba, Luis Javier García; Trujillo, Alejandra Guadalupe Silva; Orozco, Ana Lucila Sandoval; Kim, Tai-hoon

    2015-01-01

    In network communications, mixes provide protection against observers hiding the appearance of messages, patterns, length and links between senders and receivers. Statistical disclosure attacks aim to reveal the identity of senders and receivers in a communication network setting when it is protected by standard techniques based on mixes. This work aims to develop a global statistical disclosure attack to detect relationships between users. The only information used by the attacker is the number of messages sent and received by each user for each round, the batch of messages grouped by the anonymity system. A new modeling framework based on contingency tables is used. The assumptions are more flexible than those used in the literature, allowing to apply the method to multiple situations automatically, such as email data or social networks data. A classification scheme based on combinatoric solutions of the space of rounds retrieved is developed. Solutions about relationships between users are provided for all pairs of users simultaneously, since the dependence of the data retrieved needs to be addressed in a global sense. PMID:25679311

  15. Extracting Association Patterns in Network Communications

    PubMed Central

    Portela, Javier; Villalba, Luis Javier García; Trujillo, Alejandra Guadalupe Silva; Orozco, Ana Lucila Sandoval; Kim, Tai-hoon

    2015-01-01

    In network communications, mixes provide protection against observers hiding the appearance of messages, patterns, length and links between senders and receivers. Statistical disclosure attacks aim to reveal the identity of senders and receivers in a communication network setting when it is protected by standard techniques based on mixes. This work aims to develop a global statistical disclosure attack to detect relationships between users. The only information used by the attacker is the number of messages sent and received by each user for each round, the batch of messages grouped by the anonymity system. A new modeling framework based on contingency tables is used. The assumptions are more flexible than those used in the literature, allowing to apply the method to multiple situations automatically, such as email data or social networks data. A classification scheme based on combinatoric solutions of the space of rounds retrieved is developed. Solutions about relationships between users are provided for all pairs of users simultaneously, since the dependence of the data retrieved needs to be addressed in a global sense. PMID:25679311

  16. Comparative Analysis of Human Communication Networks in Selected Formal Organizations.

    ERIC Educational Resources Information Center

    Farace, Richard V.; Johnson, Jerome David

    This paper briefly describes the organization of a "data bank" containing research on communication networks, specifies the kinds of information compiled about various network properties, discusses some specific results of the work done to date, and presents some general conclusions about the overall project and its potential advantages to…

  17. Communications network design and costing model users manual

    NASA Technical Reports Server (NTRS)

    Logan, K. P.; Somes, S. S.; Clark, C. A.

    1983-01-01

    The information and procedures needed to exercise the communications network design and costing model for performing network analysis are presented. Specific procedures are included for executing the model on the NASA Lewis Research Center IBM 3033 computer. The concepts, functions, and data bases relating to the model are described. Model parameters and their format specifications for running the model are detailed.

  18. Wireless Network Communications Overview for Space Mission Operations

    NASA Technical Reports Server (NTRS)

    Fink, Patrick W.

    2009-01-01

    The mission of the On-Board Wireless Working Group (WWG) is to serve as a general CCSDS focus group for intra-vehicle wireless technologies. The WWG investigates and makes recommendations pursuant to standardization of applicable wireless network protocols, ensuring the interoperability of independently developed wireless communication assets. This document presents technical background information concerning uses and applicability of wireless networking technologies for space missions. Agency-relevant driving scenarios, for which wireless network communications will provide a significant return-on-investment benefiting the participating international agencies, are used to focus the scope of the enclosed technical information.

  19. Modeling data throughput on communication networks

    SciTech Connect

    Eldridge, J.M.

    1993-11-01

    New challenges in high performance computing and communications are driving the need for fast, geographically distributed networks. Applications such as modeling physical phenomena, interactive visualization, large data set transfers, and distributed supercomputing require high performance networking [St89][Ra92][Ca92]. One measure of a communication network`s performance is the time it takes to complete a task -- such as transferring a data file or displaying a graphics image on a remote monitor. Throughput, defined as the ratio of the number of useful data bits transmitted per the time required to transmit those bits, is a useful gauge of how well a communication system meets this performance measure. This paper develops and describes an analytical model of throughput. The model is a tool network designers can use to predict network throughput. It also provides insight into those parts of the network that act as a performance bottleneck.

  20. The Operation of a Specialized Scientific Information and Data Analysis Center With Computer Base and Associated Communications Network.

    ERIC Educational Resources Information Center

    Cottrell, William B.; And Others

    The Nuclear Safety Information Center (NSIC) is a highly sophisticated scientific information center operated at Oak Ridge National Laboratory (ORNL) for the U.S. Atomic Energy Commission. Its information file, which consists of both data and bibliographic information, is computer stored and numerous programs have been developed to facilitate the…

  1. Applications of Coding in Network Communications

    ERIC Educational Resources Information Center

    Chang, Christopher SungWook

    2012-01-01

    This thesis uses the tool of network coding to investigate fast peer-to-peer file distribution, anonymous communication, robust network construction under uncertainty, and prioritized transmission. In a peer-to-peer file distribution system, we use a linear optimization approach to show that the network coding framework significantly simplifies…

  2. A security architecture for health information networks.

    PubMed

    Kailar, Rajashekar; Muralidhar, Vinod

    2007-01-01

    Health information network security needs to balance exacting security controls with practicality, and ease of implementation in today's healthcare enterprise. Recent work on 'nationwide health information network' architectures has sought to share highly confidential data over insecure networks such as the Internet. Using basic patterns of health network data flow and trust models to support secure communication between network nodes, we abstract network security requirements to a core set to enable secure inter-network data sharing. We propose a minimum set of security controls that can be implemented without needing major new technologies, but yet realize network security and privacy goals of confidentiality, integrity and availability. This framework combines a set of technology mechanisms with environmental controls, and is shown to be sufficient to counter commonly encountered network security threats adequately. PMID:18693862

  3. Information, Education, Communication in Population.

    ERIC Educational Resources Information Center

    Hawaii Univ., Honolulu. East-West Center.

    Programs and services of the Swedish International Development Authority (SIDA) are reviewed in this report on resources available for the support of population information, education, and communication activities. Four major sections describe in concise, outline form: (1) the agency and its programs, (2) the specific program in population/family…

  4. Communicating Psychological Information in Writing.

    ERIC Educational Resources Information Center

    Iowa State Dept. of Public Instruction, Des Moines. Div. of Pupil Personnel Services.

    The guide describes approaches and considerations involved in school psychologists' communication of information in reports. Following an initial tongue in cheek discussion ("On Skinning Cats, Choking Dogs, and Leaving Lovers") of principles of report writing (such as avoiding using the language of logic and not contaminating interpretations with…

  5. Space Station Information System integrated communications concept

    NASA Technical Reports Server (NTRS)

    Muratore, J.; Bigham, J.; Whitelaw, V.; Marker, W.

    1987-01-01

    This paper presents a model for integrated communications within the Space Station Information System (SSIS). The SSIS is generally defined as the integrated set of space and ground information systems and networks which will provide required data services to the Space Station flight crew, ground operations personnel, and customer communities. This model is based on the International Standards Organization (ISO) layered model for Open Systems Interconnection (OSI). The requirements used to develop the model are presented, and the various elements of the model described.

  6. WATERSHED INFORMATION NETWORK

    EPA Science Inventory

    Resource Purpose:The Watershed Information Network is a set of about 30 web pages that are organized by topic. These pages access existing databases like the American Heritage Rivers Services database and Surf Your Watershed. WIN in itself has no data or data sets.
    L...

  7. The National Biomedical Communications Network as a Developing Structure *

    PubMed Central

    Davis, Ruth M.

    1971-01-01

    The National Biomedical Communications Network has evolved both from a set of conceptual recommendations over the last twelve years and an accumulation of needs manifesting themselves in the requests of members of the medical community. With a short history of three years this network and its developing structure have exhibited most of the stresses of technology interfacing with customer groups, and of a structure attempting to build itself upon many existing fragmentary unconnected segments of a potentially viable resourcesharing capability. In addition to addressing these topics, the paper treats a design appropriate to any network devoted to information transfer in a special interest user community. It discusses fundamentals of network design, highlighting that network structure most appropriate to a national information network. Examples are given of cost analyses of information services and certain conjectures are offered concerning the roles of national networks. PMID:5542912

  8. 75 FR 26180 - Effects on Broadband Communications Networks of Damage To or Failure of Network Equipment or...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-11

    ... Equipment or Severe Overload AGENCY: Federal Communications Commission. ACTION: Proposed rule. SUMMARY... failures in network equipment or severe overload conditions, such as would occur in natural disasters.... FOR FURTHER INFORMATION CONTACT: John Healy, Communications Systems Analysis Division, Public...

  9. Information cascade on networks

    NASA Astrophysics Data System (ADS)

    Hisakado, Masato; Mori, Shintaro

    2016-05-01

    In this paper, we discuss a voting model by considering three different kinds of networks: a random graph, the Barabási-Albert (BA) model, and a fitness model. A voting model represents the way in which public perceptions are conveyed to voters. Our voting model is constructed by using two types of voters-herders and independents-and two candidates. Independents conduct voting based on their fundamental values; on the other hand, herders base their voting on the number of previous votes. Hence, herders vote for the majority candidates and obtain information relating to previous votes from their networks. We discuss the difference between the phases on which the networks depend. Two kinds of phase transitions, an information cascade transition and a super-normal transition, were identified. The first of these is a transition between a state in which most voters make the correct choices and a state in which most of them are wrong. The second is a transition of convergence speed. The information cascade transition prevails when herder effects are stronger than the super-normal transition. In the BA and fitness models, the critical point of the information cascade transition is the same as that of the random network model. However, the critical point of the super-normal transition disappears when these two models are used. In conclusion, the influence of networks is shown to only affect the convergence speed and not the information cascade transition. We are therefore able to conclude that the influence of hubs on voters' perceptions is limited.

  10. Informal Social Networks of People with Profound Intellectual and Multiple Disabilities: Relationship with Age, Communicative Abilities and Current Living Arrangements

    ERIC Educational Resources Information Center

    Kamstra, A.; van der Putten, A. A. J.; Post, W. J.; Vlaskamp, C.

    2015-01-01

    Background: People with profound intellectual and multiple disabilities (PIMD) have limited informal social contacts. Research to determine the factors which can positively influence establishing sound informal social contacts is required. Materials and Methods: Regression analysis for 200 people with PIMD was used to analyse how age,…

  11. Computer and information networks.

    PubMed

    Greenberger, M; Aronofsky, J; McKenney, J L; Massy, W F

    1973-10-01

    The most basic conclusion coming out of the EDUCOM seminars is that computer networking must be acknowledged as an important new mode for obtaining information and computation (15). It is a real alternative that needs to be given serious attention in current planning and decision-making. Yet the fact is that many institutions are not taking account of networks when they confer on whether or how to replace their main computer. Articulation of the possibilities of computer networks goes back to the early 1960's and before, and working networks have been in evidence for several years now, both commercially and in universities. What is new, however, is the unmistakable recognition-bordering on a sense of the inevitable-that networks are finally practical and here to stay. The visionary and promotional phases of computer networks are over. It is time for hard-nosed comparative analysis (16). Another conclusion of the seminars has to do with the factors that hinder the fuller development of networking. The major problems to be overcome in applying networks to research and education are political, organizational, and economic in nature rather than technological. This is not to say that the hardware and software problems of linking computers and information systems are completely solved, but they are not the big bottlenecks at present. Research and educational institutions must find ways to organize themselves as well as their computers to work together for greater resource sharing. The coming of age of networks takes on special significance as a result of widespread dissatisfactions expressed with the present computing situation. There is a feeling that the current mode of autonomous, self-sufficient operation in the provision of computing and information services is frequently wasteful, deficient, and unresponsive to users' needs because of duplication of effort from one installation to another, incompatibilities, and inadequate documentation, program support, and user

  12. Information theoretic description of networks

    NASA Astrophysics Data System (ADS)

    Wilhelm, Thomas; Hollunder, Jens

    2007-11-01

    We present a new information theoretic approach for network characterizations. It is developed to describe the general type of networks with n nodes and L directed and weighted links, i.e., it also works for the simpler undirected and unweighted networks. The new information theoretic measures for network characterizations are based on a transmitter-receiver analogy of effluxes and influxes. Based on these measures, we classify networks as either complex or non-complex and as either democracy or dictatorship networks. Directed networks, in particular, are furthermore classified as either information spreading and information collecting networks. The complexity classification is based on the information theoretic network complexity measure medium articulation (MA). It is proven that special networks with a medium number of links ( L∼n1.5) show the theoretical maximum complexity MA=(log n)2/2. A network is complex if its MA is larger than the average MA of appropriately randomized networks: MA>MAr. A network is of the democracy type if its redundancy Rnetwork. In democracy networks all nodes are, on average, of similar importance, whereas in dictatorship networks some nodes play distinguished roles in network functioning. In other words, democracy networks are characterized by cycling of information (or mass, or energy), while in dictatorship networks there is a straight through-flow from sources to sinks. The classification of directed networks into information spreading and information collecting networks is based on the conditional entropies of the considered networks ( H(A/B)=uncertainty of sender node if receiver node is known, H(B/A)=uncertainty of receiver node if sender node is known): if H(A/B)>H(B/A), it is an information collecting network, otherwise an information spreading network. Finally, different real networks (directed and undirected, weighted and unweighted) are classified according to our general scheme.

  13. Child Rights Information Network Newsletter, 1996.

    ERIC Educational Resources Information Center

    Purbrick, Becky, Ed.

    1996-01-01

    These two newsletter issues communicate activities of the newly formed Child Rights Information Network (CRIN) and report on emerging information resources and activities concerning children and child rights. The January 1996 issue describes the history of CRIN, provides updates on the activities of projects linked to CRIN, and summarizes…

  14. A Novel Routing Strategy on Space Communication Network

    NASA Astrophysics Data System (ADS)

    LI, Yujian; WANG, Xu-Liang; Zhen-dong, XI; Bing-hong, WANG

    2016-02-01

    In this paper, we propose an effective routing strategy on the basis of the so-called nearest neighbor search strategy by introducing a preferential time delay exponent β. Traffic dynamics both near and far away from the critical generating rate Rc are discussed. Simulation results demonstrate that the optimal performance of the system corresponds to β =-0.5. Due to the low cost of acquiring nearest-neighbor information and the strongly improved network capacity, our strategy may be useful and reasonable for the protocol designing of modern communication networks and space communication networks.

  15. The geospatial characteristics of a social movement communication network.

    PubMed

    Conover, Michael D; Davis, Clayton; Ferrara, Emilio; McKelvey, Karissa; Menczer, Filippo; Flammini, Alessandro

    2013-01-01

    Social movements rely in large measure on networked communication technologies to organize and disseminate information relating to the movements' objectives. In this work we seek to understand how the goals and needs of a protest movement are reflected in the geographic patterns of its communication network, and how these patterns differ from those of stable political communication. To this end, we examine an online communication network reconstructed from over 600,000 tweets from a thirty-six week period covering the birth and maturation of the American anticapitalist movement, Occupy Wall Street. We find that, compared to a network of stable domestic political communication, the Occupy Wall Street network exhibits higher levels of locality and a hub and spoke structure, in which the majority of non-local attention is allocated to high-profile locations such as New York, California, and Washington D.C. Moreover, we observe that information flows across state boundaries are more likely to contain framing language and references to the media, while communication among individuals in the same state is more likely to reference protest action and specific places and times. Tying these results to social movement theory, we propose that these features reflect the movement's efforts to mobilize resources at the local level and to develop narrative frames that reinforce collective purpose at the national level. PMID:23483885

  16. Scalable Hierarchical Network Management System for Displaying Network Information in Three Dimensions

    NASA Technical Reports Server (NTRS)

    George, Jude (Inventor); Schlecht, Leslie (Inventor); McCabe, James D. (Inventor); LeKashman, John Jr. (Inventor)

    1998-01-01

    A network management system has SNMP agents distributed at one or more sites, an input output module at each site, and a server module located at a selected site for communicating with input output modules, each of which is configured for both SNMP and HNMP communications. The server module is configured exclusively for HNMP communications, and it communicates with each input output module according to the HNMP. Non-iconified, informationally complete views are provided of network elements to aid in network management.

  17. Network management of highly adaptive communication networks

    NASA Astrophysics Data System (ADS)

    Kennington, Jeffrey L.; Helgason, Richard V.; Colombi, John M.

    1988-02-01

    This report documents networking models, network solutions, programming techniques for parallel processing, and parallelled algorithm comparisons. Several papers are contained in the report. An operational research model and associated mathematics are presented for a three node network. A multi-media nodal simulation is developed to optimally assign trunks. A new mathematical approach is shown for solving equal flow problems. This technique makes greater use of the side constraints structure with computational solutions given. Also developed are the mathematical theory and justification of using the quadrant interlocking factorization for solving the simplex algorithm on a parallel processor. Lastly, computational results of solving minimal spanning tree problems, on a parallel processor are presented.

  18. Internetworking satellite and local exchange networks for personal communications applications

    NASA Technical Reports Server (NTRS)

    Wolff, Richard S.; Pinck, Deborah

    1993-01-01

    The demand for personal communications services has shown unprecedented growth, and the next decade and beyond promise an era in which the needs for ubiquitous, transparent and personalized access to information will continue to expand in both scale and scope. The exchange of personalized information is growing from two-way voice to include data communications, electronic messaging and information services, image transfer, video, and interactive multimedia. The emergence of new land-based and satellite-based wireless networks illustrates the expanding scale and trend toward globalization and the need to establish new local exchange and exchange access services to meet the communications needs of people on the move. An important issue is to identify the roles that satellite networking can play in meeting these new communications needs. The unique capabilities of satellites, in providing coverage to large geographic areas, reaching widely dispersed users, for position location determination, and in offering broadcast and multicast services, can complement and extend the capabilities of terrestrial networks. As an initial step in exploring the opportunities afforded by the merger of satellite-based and land-based networks, several experiments utilizing the NASA ACTS satellite and the public switched local exchange network were undertaken to demonstrate the use of satellites in the delivery of personal communications services.

  19. A Communication Network for Educational Researchers.

    ERIC Educational Resources Information Center

    Pierce, Jean; Cooley, William W.

    1985-01-01

    Discusses application of microcomputer technology to educational research and describes the possible uses of computer networking for communication with colleagues. Focuses on the organization and structure of the Education Research Forum on CompuServe. Considers advantages and costs of networking in general and for the American Educational…

  20. Iowa Communications Network Enhancing Education in Iowa.

    ERIC Educational Resources Information Center

    Ivanovic, Greta

    1995-01-01

    Describes the Iowa Communications Network, a statewide fiber optic network capable of transporting interactive, two-way audio, video, voice, and data signals. Topics include statewide cooperation among educational and state organizations; classroom design, including interactive classrooms; access to the Internet; and use by noneducational…

  1. Predicting Employee Turnover from Communication Networks.

    ERIC Educational Resources Information Center

    Feeley, Thomas H.; Barnett, George A.

    1997-01-01

    Investigates three social network models of employee turnover: a structural equivalence model, a social influence model, and an erosion model. Administers a communication network questionnaire to all 170 employees of an organization. Finds support for all three models of turnover, with the erosion model explaining more of the variance than do the…

  2. Stress Testing of Data-Communication Networks

    NASA Technical Reports Server (NTRS)

    Leucht, Kurt; Bedette, Guy

    2006-01-01

    NetStress is a computer program that stress-tests a data-communication network and components thereof. NetStress comprises two components running, respectively, in a transmitting system and a receiving system connected to a network under test

  3. Exploring Collective Dynamics in Communication Networks

    PubMed Central

    Yuan, Jian; Mills, Kevin

    2002-01-01

    A communication network, such as the Internet, comprises a complex system where cooperative phenomena may emerge from interactions among various traffic flows generated and forwarded by individual nodes. To identify and understand such phenomena, we model a network as a two-dimensional cellular automaton. We suspect such models can promote better understanding of the spatial-temporal evolution of network congestion, and other emergent phenomena in communication networks. To search the behavior space of the model, we study dynamic patterns arising from interactions among traffic flows routed across shared network nodes, as we employ various configurations of parameters and two different congestion-control algorithms. In this paper, we characterize correlation in congestion behavior within the model at different system sizes and time granularities. As expected, we find that long-range dependence (LRD) appears at some time granularities, and that for a given network size LRD decays as time granularity increases. As network size increases, we find that long-range dependence exists at larger time scales. To distinguish effects due to network size from effects due to collective phenomena, we compare congestion behavior within networks of selected sizes to congestion behavior within comparably sized sub-areas in a larger network. We find stronger long-range dependence for sub-areas within the larger network. This suggests the importance of modeling networks of sufficiently large size when studying the effects of collective dynamics.

  4. Environmental effects of information and communications technologies.

    PubMed

    Williams, Eric

    2011-11-17

    The digital revolution affects the environment on several levels. Most directly, information and communications technology (ICT) has environmental impacts through the manufacturing, operation and disposal of devices and network equipment, but it also provides ways to mitigate energy use, for example through smart buildings and teleworking. At a broader system level, ICTs influence economic growth and bring about technological and societal change. Managing the direct impacts of ICTs is more complex than just producing efficient devices, owing to the energetically expensive manufacturing process, and the increasing proliferation of devices needs to be taken into account. PMID:22094696

  5. Challenges of Integrating NASAs Space Communication Networks

    NASA Technical Reports Server (NTRS)

    Reinert, Jessica M.; Barnes, Patrick

    2013-01-01

    The transition to new technology, innovative ideas, and resistance to change is something that every industry experiences. Recent examples of this shift are changing to using robots in the assembly line construction of automobiles or the increasing use of robotics for medical procedures. Most often this is done with cost-reduction in mind, though ease of use for the customer is also a driver. All industries experience the push to increase efficiency of their systems; National Aeronautics and Space Administration (NASA) and the commercial space industry are no different. NASA space communication services are provided by three separately designed, developed, maintained, and operated communications networks known as the Deep Space Network (DSN), Near Earth Network (NEN) and Space Network (SN). The Space Communications and Navigation (SCaN) Program is pursuing integration of these networks and has performed a variety of architecture trade studies to determine what integration options would be the most effective in achieving a unified user mission support organization, and increase the use of common operational equipment and processes. The integration of multiple, legacy organizations and existing systems has challenges ranging from technical to cultural. The existing networks are the progeny of the very first communication and tracking capabilities implemented by NASA and the Jet Propulsion Laboratory (JPL) more than 50 years ago and have been customized to the needs of their respective user mission base. The technical challenges to integrating the networks are many, though not impossible to overcome. The three distinct networks provide the same types of services, with customizable data rates, bandwidth, frequencies, and so forth. The differences across the networks have occurred in effort to satisfy their user missions' needs. Each new requirement has made the networks more unique and harder to integrate. The cultural challenges, however, have proven to be a

  6. Challenges of Integrating NASA's Space Communications Networks

    NASA Technical Reports Server (NTRS)

    Reinert, Jessica; Barnes, Patrick

    2013-01-01

    The transition to new technology, innovative ideas, and resistance to change is something that every industry experiences. Recent examples of this shift are changing to using robots in the assembly line construction of automobiles or the increasing use of robotics for medical procedures. Most often this is done with cost-reduction in mind, though ease of use for the customer is also a driver. All industries experience the push to increase efficiency of their systems; National Aeronautics and Space Administration (NASA) and the commercial space industry are no different. NASA space communication services are provided by three separately designed, developed, maintained, and operated communications networks known as the Deep Space Network (DSN), Near Earth Network (NEN) and Space Network (SN). The Space Communications and Navigation (SCaN) Program is pursuing integration of these networks and has performed a variety of architecture trade studies to determine what integration options would be the most effective in achieving a unified user mission support organization, and increase the use of common operational equipment and processes. The integration of multiple, legacy organizations and existing systems has challenges ranging from technical to cultural. The existing networks are the progeny of the very first communication and tracking capabilities implemented by NASA and the Jet Propulsion Laboratory (JPL) more than 50 years ago and have been customized to the needs of their respective user mission base. The technical challenges to integrating the networks are many, though not impossible to overcome. The three distinct networks provide the same types of services, with customizable data rates, bandwidth, frequencies, and so forth. The differences across the networks have occurred in effort to satisfy their user missions' needs. Each new requirement has made the networks more unique and harder to integrate. The cultural challenges, however, have proven to be a

  7. Information transport in multiplex networks

    NASA Astrophysics Data System (ADS)

    Pu, Cunlai; Li, Siyuan; Yang, Xianxia; Yang, Jian; Wang, Kai

    2016-04-01

    In this paper, we study information transport in multiplex networks comprised of two coupled subnetworks. The upper subnetwork, called the logical layer, employs the shortest paths protocol to determine the logical paths for packets transmission, while the lower subnetwork acts as the physical layer, in which packets are delivered by the biased random walk mechanism characterized with a parameter α. Through simulation, we obtain the optimal α corresponding to the maximum network lifetime and the maximum number of the arrival packets. Assortative coupling is better than random coupling and disassortative coupling, since it achieves better transmission performance. Generally, the more homogeneous the lower subnetwork is, the better the transmission performance, which is the opposite for the upper subnetwork. Finally, we propose an attack centrality for nodes based on the topological information of both subnetworks, and investigate the transmission performance under targeted attacks. Our work aids in understanding the spread and robustness issues of multiplex networks and provides some clues about the design of more efficient and robust routing architectures in communication systems.

  8. System Design for Nano-Network Communications

    NASA Astrophysics Data System (ADS)

    ShahMohammadian, Hoda

    The potential applications of nanotechnology in a wide range of areas necessities nano-networking research. Nano-networking is a new type of networking which has emerged by applying nanotechnology to communication theory. Therefore, this dissertation presents a framework for physical layer communications in a nano-network and addresses some of the pressing unsolved challenges in designing a molecular communication system. The contribution of this dissertation is proposing well-justified models for signal propagation, noise sources, optimum receiver design and synchronization in molecular communication channels. The design of any communication system is primarily based on the signal propagation channel and noise models. Using the Brownian motion and advection molecular statistics, separate signal propagation and noise models are presented for diffusion-based and flow-based molecular communication channels. It is shown that the corrupting noise of molecular channels is uncorrelated and non-stationary with a signal dependent magnitude. The next key component of any communication system is the reception and detection process. This dissertation provides a detailed analysis of the effect of the ligand-receptor binding mechanism on the received signal, and develops the first optimal receiver design for molecular communications. The bit error rate performance of the proposed receiver is evaluated and the impact of medium motion on the receiver performance is investigated. Another important feature of any communication system is synchronization. In this dissertation, the first blind synchronization algorithm is presented for the molecular communication channels. The proposed algorithm uses a non-decision directed maximum likelihood criterion for estimating the channel delay. The Cramer-Rao lower bound is also derived and the performance of the proposed synchronization algorithm is evaluated by investigating its mean square error.

  9. Coupled map networks as communication schemes

    NASA Astrophysics Data System (ADS)

    García, P.; Parravano, A.; Cosenza, M. G.; Jiménez, J.; Marcano, A.

    2002-04-01

    Networks of chaotic coupled maps are considered as string and language generators. It is shown that such networks can be used as encrypting systems where the cipher text contains information about the evolution of the network and also about the way to select the plain text symbols from the string associated with the network evolution. The secret key provides the network parameters, such as the coupling strengths.

  10. Network design tool for EHF satellite communications networks

    NASA Astrophysics Data System (ADS)

    Norvell, S.; Brown, G. J.

    1983-06-01

    This document describes the design concept of the network design tool. The network design tool (NDT) is a collection of analytical techniques, algorithms and simulation methods that may be used to characterize the performance of a computer communication network. Much work has been done over the past several years in network performance analysis and many techniques have been developed or proposed. Each of these methods applies to a particular aspect of the network design and is based on a particular modeling point of view. We define the computer communication network and then describe the different ways the network may be modeled. Each network model is related to the particular design problem being addressed. The various analytical approaches are briefly described and their relationship to the network models discussed. Chapter 2 is a survey of the major approaches to specific network design problems while chapters 3 and 4 discuss two fairly well defined areas of network analysis: topological design/optimization and protocol validation. Chapter 5 is a survey of network design tools presently available locally or on the advanced research projects agency network (ARPANET). Finally, chapter 6 presents an outline of the NDT specification.

  11. [Modern network technologies for data communication in the hospital].

    PubMed

    Pelikan, E; Kotter, E; Jäger, D; Langer, M; Timmermann, U

    1999-04-01

    Modern network technologies provide the basic infrastructure for information and communication systems in the hospital today. The goal to build up a universal network infrastructure which meets the broadly varied requirements. Analysis of data communication in the hospital and the evaluation of established network technologies, as well as new developments, leads to the switching concept as the suitable solution. Two technologies play the major role in building enterprise networks: the Ethernet family, based on frame switching, and ATM, based on cell switching. Orientation on established standards is the key to free system choice and grants interoperability between systems from different manufacturers. However, the network design must meet the application and system architecture of the information technology in order to achieve successful mapping of the involved communication profiles. This means scaling of the bandwidth as needed, suitable segmenting of the network and resilient links. In a further step, policy-based networking takes advantages of prioritizing critical applications and therefore reduces interdependencies across the network. PMID:10337699

  12. Origin of cells and network information

    PubMed Central

    Tanabe, Shihori

    2015-01-01

    All cells are derived from one cell, and the origin of different cell types is a subject of curiosity. Cells construct life through appropriately timed networks at each stage of development. Communication among cells and intracellular signaling are essential for cell differentiation and for life processes. Cellular molecular networks establish cell diversity and life. The investigation of the regulation of each gene in the genome within the cellular network is therefore of interest. Stem cells produce various cells that are suitable for specific purposes. The dynamics of the information in the cellular network changes as the status of cells is altered. The components of each cell are subject to investigation. PMID:25914760

  13. Optimizing a Middle School's Network Capabilities for Accessing Information, Improving School Communications and Interacting with the Global Community through Network Training.

    ERIC Educational Resources Information Center

    Richardson, Laura A.

    The problem addressed in this practicum was that most teachers at the author's middle school were not fully using the school's network resources in their day-to-day classroom activities, in spite of district technology initiatives. The goal of the practicum was to empower a cadre of representative mentor teachers to fully utilize the school…

  14. Scholarly Information Network

    NASA Astrophysics Data System (ADS)

    Ginsparg, Paul

    I review the background and some recent trends of a particular scholarly information network, arXiv.org, and discuss some of its implications for new scholarly publication models. If we were to start from scratch today to design a quality-controlled archive and distribution system for scientific and technical information, it could take a very different form from what has evolved in the past decade from pre-existing print infrastructure. Near-term advances in automated classification systems, authoring tools, and document formats will facilitate efficient datamining and long-term archival stability, and I discuss how these could provide not only more efficient means of accessing and navigating the information, but also more cost-effective means of authentication and quality control. Finally, I illustrate the use of machine learning techniques to analyze, structure, maintain, and evolve a large online corpus of academic literature. An emerging field of research can be identified as part of an existing corpus, permitting the implementation of a more coherent community structure for its network of practitioners.

  15. Communication cliques in mobile phone calling networks

    NASA Astrophysics Data System (ADS)

    Li, Ming-Xia; Xie, Wen-Jie; Jiang, Zhi-Qiang; Zhou, Wei-Xing

    2015-11-01

    People in modern societies form different social networks through numerous means of communication. These communication networks reflect different aspects of human's societal structure. The billing records of calls among mobile phone users enable us to construct a directed calling network (DCN) and its Bonferroni network (SVDCN) in which the preferential communications are statistically validated. Here we perform a comparative investigation of the cliques of the original DCN and its SVDCN constructed from the calling records of more than nine million individuals in Shanghai over a period of 110 days. We find that the statistical properties of the cliques of the two calling networks are qualitatively similar and the clique members in the DCN and the SVDCN exhibit idiosyncratic behaviors quantitatively. Members in large cliques are found to be spatially close to each other. Based on the clique degree profile of each mobile phone user, the most active users in the two calling networks can be classified in to several groups. The users in different groups are found to have different calling behaviors. Our study unveils interesting communication behaviors among mobile phone users that are densely connected to each other.

  16. Multiple communication networks for a radiological PACS

    NASA Astrophysics Data System (ADS)

    Wong, Albert W. K.; Stewart, Brent K.; Lou, Shyhliang A.; Chan, Kelby K.; Huang, H. K.

    1991-07-01

    The authors have implemented a communication network connecting multiple buildings for their picture archiving and communication system (PACS) in the Radiology Department at UCLA. The network consists of three types of local area networks (LANs) and a 1.0-km fiber-optic link connecting the outpatient and inpatient facilities. Images from radiologic imaging devices (4 CT scanners, 5 MR scanners, 4 CR units and 5 film digitizers) are transmitted to the acquisition computers via the Ethernet LAN. The fiber distributed data interface (FDDI) LAN then provides data communication among the cluster controllers, the acquisition computers, and the database servers. A 1-gigabit UltraNet LAN is used to route images from the cluster controllers to remote display workstations. All inter-building connections are through fiber-optic cables. Among these multiple networks, Ethernet offers multi-access to the multimodal PACS in image acquisition, FDDI controls a fast data flow so that all acquired images have a shorter residence time on local disks, and UltraNet provides high-speed transfer of images from the cluster controllers to the display workstations. The three-tiered functionality of Ethernet, FDDI, and UltraNet eliminates network traffic bottlenecks and hence provides high performance in image communication. The delay time of a 2K X 2K X 8-bit CR image (4 MBytes) from acquisition to display is less than 5 minutes. In addition, the standard Ethernet serves as a backup to guarantee network connectivity of the entire PACS.

  17. Ad Hoc Networks: Headline 2000 Communications Analysis

    NASA Astrophysics Data System (ADS)

    Blair, W. D.; Reynolds, A. B.

    2002-06-01

    This report examines unit location data and terrain from Headline 2000 to investigate communications networks within the maneuver units. Within the Enhanced Combat Force timeframe, such units would be supported by a Tactical Data Distribution Sub-system (TDDS). This is envisaged as an ad hoc network changing its topology as units maneuver across the battlespace. The report describes approaches that can be applied to Headline 2000 and other data to characterize the nature of the network topology, both statically and as it changes over time, in order to explore the impact on the TDDS network capacity and hence to hence to assist in elucidating consequent requirements of a candidate TDDS.

  18. Data Communications and Networking. Curriculum Improvement Project. Region II.

    ERIC Educational Resources Information Center

    Easter, Diane

    This course curriculum is intended for use by community college instructors and administrators in implementing a data communications networking course. A student course syllabus provides this information: credit hours, catalog description, prerequisites, required text, instructional process, objectives, student evaluation, and class schedule. A…

  19. SpecialNet. A National Computer-Based Communications Network.

    ERIC Educational Resources Information Center

    Morin, Alfred J.

    1986-01-01

    "SpecialNet," a computer-based communications network for educators at all administrative levels, has been established and is managed by National Systems Management, Inc. Users can send and receive electronic mail, share information on electronic bulletin boards, participate in electronic conferences, and send reports and other documents to each…

  20. Communicability reveals a transition to coordinated behavior in multiplex networks.

    PubMed

    Estrada, Ernesto; Gómez-Gardeñes, Jesús

    2014-04-01

    We analyze the flow of information in multiplex networks by means of the communicability function. First, we generalize this measure from its definition from simple graphs to multiplex networks. Then, we study its relevance for the analysis of real-world systems by studying a social multiplex where information flows using formal-informal channels and an air transportation system where the layers represent different air companies. Accordingly, the communicability, which is essential for the good performance of these complex systems, emerges at a systemic operation point in the multiplex where the performance of the layers operates in a coordinated way very differently from the state represented by a collection of unconnected networks. PMID:24827305

  1. The NASA Space Communications Data Networking Architecture

    NASA Technical Reports Server (NTRS)

    Israel, David J.; Hooke, Adrian J.; Freeman, Kenneth; Rush, John J.

    2006-01-01

    The NASA Space Communications Architecture Working Group (SCAWG) has recently been developing an integrated agency-wide space communications architecture in order to provide the necessary communication and navigation capabilities to support NASA's new Exploration and Science Programs. A critical element of the space communications architecture is the end-to-end Data Networking Architecture, which must provide a wide range of services required for missions ranging from planetary rovers to human spaceflight, and from sub-orbital space to deep space. Requirements for a higher degree of user autonomy and interoperability between a variety of elements must be accommodated within an architecture that necessarily features minimum operational complexity. The architecture must also be scalable and evolvable to meet mission needs for the next 25 years. This paper will describe the recommended NASA Data Networking Architecture, present some of the rationale for the recommendations, and will illustrate an application of the architecture to example NASA missions.

  2. Network Information System

    Energy Science and Technology Software Center (ESTSC)

    1996-05-01

    The Network Information System (NWIS) was initially implemented in May 1996 as a system in which computing devices could be recorded so that unique names could be generated for each device. Since then the system has grown to be an enterprise wide information system which is integrated with other systems to provide the seamless flow of data through the enterprise. The system Iracks data for two main entities: people and computing devices. The following aremore » the type of functions performed by NWIS for these two entities: People Provides source information to the enterprise person data repository for select contractors and visitors Generates and tracks unique usernames and Unix user IDs for every individual granted cyber access Tracks accounts for centrally managed computing resources, and monitors and controls the reauthorization of the accounts in accordance with the DOE mandated interval Computing Devices Generates unique names for all computing devices registered in the system Tracks the following information for each computing device: manufacturer, make, model, Sandia property number, vendor serial number, operating system and operating system version, owner, device location, amount of memory, amount of disk space, and level of support provided for the machine Tracks the hardware address for network cards Tracks the P address registered to computing devices along with the canonical and alias names for each address Updates the Dynamic Domain Name Service (DDNS) for canonical and alias names Creates the configuration files for DHCP to control the DHCP ranges and allow access to only properly registered computers Tracks and monitors classified security plans for stand-alone computers Tracks the configuration requirements used to setup the machine Tracks the roles people have on machines (system administrator, administrative access, user, etc...) Allows systems administrators to track changes made on the machine (both hardware and software) Generates an

  3. Geoscience Information Network

    NASA Astrophysics Data System (ADS)

    Allison, M. L.; Gundersen, L. C.

    2007-12-01

    Geological surveys in the USA have an estimated 2,000-3,000 databases that represent one of the largest, long- term information resources on the geology of the United States and collectively constitute a national geoscience data "backbone" for research and applications. An NSF-supported workshop in February, 2007, among representatives of the Association of American State Geologists (AASG) and the USGS, recommended that "the nation's geological surveys develop a national geoscience information framework that is distributed, interoperable, uses open source standards and common protocols, respects and acknowledges data ownership, fosters communities of practice to grow, and develops new web services and clients." The AASG and USGS have formally endorsed the workshop recommendations and formed a joint Steering Committee to pursue design and implementation of the Geoscience Information Network (GIN). GIN is taking a modular approach in assembling the network: 1. Agreement on open-source standards and common protocols through the use of Open Geospatial Consortium (OGC) standards. 2. A data exchange model utilizing the geoscience mark-up language GeoSciML, an OGC GML-based application. 3. A prototype data discovery tool (National Digital Catalogue - NDC) developing under the National Geological and Geophysical Data Preservation Program run by the USGS. 4. Data integration tools developed or planned by a number of independent projects. A broader NSF-sponsored workshop in March 2007 examined what direction the geoinformatics community in the US should take towards developing a National Geoinformatics System. The final report stated that, "It was clear that developing such a system should involve a partnership between academia, government, and industry that should be closely connected to the efforts of the U. S. Geological Survey and the state geological surveys..." The GIN is collaborating with 1-G Europe, a coalition of 27 European geological surveys in the One

  4. Self-assembly of information in networks

    NASA Astrophysics Data System (ADS)

    Rosvall, M.; Sneppen, K.

    2006-06-01

    We model self-assembly of information in networks to investigate necessary conditions for building a global perception of a system by local communication. Our approach is to let agents chat in a model system to self-organize distant communication pathways. We demonstrate that simple local rules allow agents to build a perception of the system, that is robust to dynamical changes and mistakes. We find that messages are most effectively forwarded in the presence of hubs, while transmission in hub-free networks is more robust against misinformation and failures.

  5. Establishing communication networks for health promotion in industrial settings.

    PubMed

    Heirich, M A; Cameron, V; Erfurt, J C; Foote, A; Gregg, W

    1989-11-01

    Abstract Health educators, medical personnel, and managers interested in worksite efforts to change health behaviors often face problems in communicating effectively with rank and file members of the workforce. This article describes an effective strategy for getting health information flowing among an industrial workforce and changing health behaviors. Identifying effective communication routes at a worksite and creating new ones, establishing relationships with key information carriers, and making health information salient to potential communicators are keys to successful information flow. Wellness Committees can provide access to formal communication routes, which may or may not work for health information. One-to-one counseling and development of buddy systems, however, create short-link, health-oriented communication networks. If people whom large numbers of employees contact for plant business get recruited into these health networks, information spreads rapidly. Poster posting can generate interaction with people so that they read and talk about health messages. Unusual motion, sound, and messages can call attention to special events. Using these methods has increased participation in specific health activities from a handful to between fifty and one hundred people at a time. PMID:22204404

  6. An underwater optical wireless communication network

    NASA Astrophysics Data System (ADS)

    Arnon, Shlomi

    2009-08-01

    The growing need for underwater observation and sub-sea monitoring systems has stimulated considerable interest in advancing the enabling technologies of underwater wireless communication and underwater sensor networks. This communication technology is expected to play an important role in investigating climate change, in monitoring biological, bio-geochemical, evolutionary and ecological changes in the sea, ocean and lake environments and in helping to control and maintain oil production facilities and harbors using unmanned underwater vehicles (UUVs), submarines, ships, buoys, and divers. However, the present technology of underwater acoustic communication cannot provide the high data rate required to investigate and monitor these environments and facilities. Optical wireless communication has been proposed as the best alternative to meet this challenge. We present models of three kinds of optical wireless communication links a) a line-of-sight link, b) a modulating retro-reflector link and c) a reflective link, all of which can provide the required data rate. We analyze the link performance based on these models. From the analysis, it is clear that as the water absorption increases, the communication performance decreases dramatically for the three link types. However, by using the scattered lighted it was possible to mitigate this decrease in some cases. We conclude from the analysis that a high data rate underwater optical wireless network is a feasible solution for emerging applications such as UUV to UUV links and networks of sensors, and extended ranges in these applications could be achieved by applying a multi-hop concept.

  7. A Communications Network for Cislunar Operations

    NASA Technical Reports Server (NTRS)

    Burleigh, Scott

    2012-01-01

    Reliable and efficient communications will be critical to the success of commercial flight operations in cislunar space. The Internet is not well-suited to meeting this requirement. But the Delay-Tolerant Networking (DTN) architecture is. The DTN protocols are well-documented and implementations are mature. We think DTN will be ready to support low-cost, low-risk cislunar networking by the time the vehicles are in place.

  8. Hybrid Mobile Communication Networks for Planetary Exploration

    NASA Technical Reports Server (NTRS)

    Alena, Richard; Lee, Charles; Walker, Edward; Osenfort, John; Stone, Thom

    2007-01-01

    A paper discusses the continuing work of the Mobile Exploration System Project, which has been performing studies toward the design of hybrid communication networks for future exploratory missions to remote planets. A typical network could include stationary radio transceivers on a remote planet, mobile radio transceivers carried by humans and robots on the planet, terrestrial units connected via the Internet to an interplanetary communication system, and radio relay transceivers aboard spacecraft in orbit about the planet. Prior studies have included tests on prototypes of these networks deployed in Arctic and desert regions chosen to approximate environmental conditions on Mars. Starting from the findings of the prior studies, the paper discusses methods of analysis, design, and testing of the hybrid communication networks. It identifies key radio-frequency (RF) and network engineering issues. Notable among these issues is the study of wireless LAN throughput loss due to repeater use, RF signal strength, and network latency variations. Another major issue is that of using RF-link analysis to ensure adequate link margin in the face of statistical variations in signal strengths.

  9. Extracting information from multiplex networks.

    PubMed

    Iacovacci, Jacopo; Bianconi, Ginestra

    2016-06-01

    Multiplex networks are generalized network structures that are able to describe networks in which the same set of nodes are connected by links that have different connotations. Multiplex networks are ubiquitous since they describe social, financial, engineering, and biological networks as well. Extending our ability to analyze complex networks to multiplex network structures increases greatly the level of information that is possible to extract from big data. For these reasons, characterizing the centrality of nodes in multiplex networks and finding new ways to solve challenging inference problems defined on multiplex networks are fundamental questions of network science. In this paper, we discuss the relevance of the Multiplex PageRank algorithm for measuring the centrality of nodes in multilayer networks and we characterize the utility of the recently introduced indicator function Θ̃(S) for describing their mesoscale organization and community structure. As working examples for studying these measures, we consider three multiplex network datasets coming for social science. PMID:27368796

  10. Extracting information from multiplex networks

    NASA Astrophysics Data System (ADS)

    Iacovacci, Jacopo; Bianconi, Ginestra

    2016-06-01

    Multiplex networks are generalized network structures that are able to describe networks in which the same set of nodes are connected by links that have different connotations. Multiplex networks are ubiquitous since they describe social, financial, engineering, and biological networks as well. Extending our ability to analyze complex networks to multiplex network structures increases greatly the level of information that is possible to extract from big data. For these reasons, characterizing the centrality of nodes in multiplex networks and finding new ways to solve challenging inference problems defined on multiplex networks are fundamental questions of network science. In this paper, we discuss the relevance of the Multiplex PageRank algorithm for measuring the centrality of nodes in multilayer networks and we characterize the utility of the recently introduced indicator function Θ ˜ S for describing their mesoscale organization and community structure. As working examples for studying these measures, we consider three multiplex network datasets coming for social science.

  11. Environmental Uncertainty and Communication Network Complexity: A Cross-System, Cross-Cultural Test.

    ERIC Educational Resources Information Center

    Danowski, James

    An infographic model is proposed to account for the operation of systems within their information environments. Infographics is a communication paradigm used to indicate the clustering of information processing variables in communication systems. Four propositions concerning environmental uncertainty and internal communication network complexity,…

  12. Communication Networks in the Brain

    PubMed Central

    Lovinger, David M.

    2008-01-01

    Nerve cells (i.e., neurons) communicate via a combination of electrical and chemical signals. Within the neuron, electrical signals driven by charged particles allow rapid conduction from one end of the cell to the other. Communication between neurons occurs at tiny gaps called synapses, where specialized parts of the two cells (i.e., the presynaptic and postsynaptic neurons) come within nanometers of one another to allow for chemical transmission. The presynaptic neuron releases a chemical (i.e., a neurotransmitter) that is received by the postsynaptic neuron’s specialized proteins called neurotransmitter receptors. The neurotransmitter molecules bind to the receptor proteins and alter postsynaptic neuronal function. Two types of neurotransmitter receptors exist—ligand-gated ion channels, which permit rapid ion flow directly across the outer cell membrane, and G-protein–coupled receptors, which set into motion chemical signaling events within the cell. Hundreds of molecules are known to act as neurotransmitters in the brain. Neuronal development and function also are affected by peptides known as neurotrophins and by steroid hormones. This article reviews the chemical nature, neuronal actions, receptor subtypes, and therapeutic roles of several transmitters, neurotrophins, and hormones. It focuses on neurotransmitters with important roles in acute and chronic alcohol effects on the brain, such as those that contribute to intoxication, tolerance, dependence, and neurotoxicity, as well as maintained alcohol drinking and addiction. PMID:23584863

  13. Social Networking and Smart Technology: Viable Environmental Communication Tools…?

    NASA Astrophysics Data System (ADS)

    Montain, J.; Byrne, J. M.

    2010-12-01

    To what extent do popular social networking channels represent a viable means for disseminating information regarding environmental change to the general public? Are new forms of communication such as YouTube™, Facebook™, MySpace™ and Twitter™ and smart devices such as iPhone™ and BlackBerry™ useful and effective in terms motivating people into social action and behavioural modification; or do they simply pay ‘lip service’ to these pressing environmental issues? This project will explore the background connections between social networking and environmental communication and education; and outline why such tools might be an appropriate way to connect to a broad audience in an efficient and unconventional manner. Further, research will survey the current prevalence of reliable environmental change information on social networking Internet-based media; and finally, suggestions for improved strategies and new directions will be provided.

  14. Protocol for Communication Networking for Formation Flying

    NASA Technical Reports Server (NTRS)

    Jennings, Esther; Okino, Clayton; Gao, Jay; Clare, Loren

    2009-01-01

    An application-layer protocol and a network architecture have been proposed for data communications among multiple autonomous spacecraft that are required to fly in a precise formation in order to perform scientific observations. The protocol could also be applied to other autonomous vehicles operating in formation, including robotic aircraft, robotic land vehicles, and robotic underwater vehicles. A group of spacecraft or other vehicles to which the protocol applies could be characterized as a precision-formation- flying (PFF) network, and each vehicle could be characterized as a node in the PFF network. In order to support precise formation flying, it would be necessary to establish a corresponding communication network, through which the vehicles could exchange position and orientation data and formation-control commands. The communication network must enable communication during early phases of a mission, when little positional knowledge is available. Particularly during early mission phases, the distances among vehicles may be so large that communication could be achieved only by relaying across multiple links. The large distances and need for omnidirectional coverage would limit communication links to operation at low bandwidth during these mission phases. Once the vehicles were in formation and distances were shorter, the communication network would be required to provide high-bandwidth, low-jitter service to support tight formation-control loops. The proposed protocol and architecture, intended to satisfy the aforementioned and other requirements, are based on a standard layered-reference-model concept. The proposed application protocol would be used in conjunction with conventional network, data-link, and physical-layer protocols. The proposed protocol includes the ubiquitous Institute of Electrical and Electronics Engineers (IEEE) 802.11 medium access control (MAC) protocol to be used in the datalink layer. In addition to its widespread and proven use in

  15. Information Networking in Population Education.

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific, and Cultural Organization, Bangkok (Thailand). Regional Office for Education in Asia and the Pacific.

    The rapidly increasing body of knowledge in population education has created the need for systematic and effective information services. Information networking entails sharing resources so that the information needs of all network participants are met. The goals of this manual are to: (1) instill in population education specialists a more…

  16. Information Systems and Business Communication.

    ERIC Educational Resources Information Center

    Beswick, Raymond W., Ed.; Williams, Alfred B., Ed.

    Intended to provide orientation about the integration of business communication, business systems, and the researching and teaching of business communication, this books offers articles on a variety of topics concerning business communication. Titles of the articles and their authors are as follows: (1) "Office Technology: Voice Store-and-Forward"…

  17. Communication services for advanced network applications.

    SciTech Connect

    Bresnahan, J.; Foster, I.; Insley, J.; Toonen, B.; Tuecke, S.

    1999-06-10

    Advanced network applications such as remote instrument control, collaborative environments, and remote I/O are distinguished by traditional applications such as videoconferencing by their need to create multiple, heterogeneous flows with different characteristics. For example, a single application may require remote I/O for raw datasets, shared controls for a collaborative analysis system, streaming video for image rendering data, and audio for collaboration. Furthermore, each flow can have different requirements in terms of reliability, network quality of service, security, etc. They argue that new approaches to communication services, protocols, and network architecture are required both to provide high-level abstractions for common flow types and to support user-level management of flow creation and quality. They describe experiences with the development of such applications and communication services.

  18. Estimating computer communication network performance using network simulations

    SciTech Connect

    Garcia, A.B.

    1985-01-01

    A generalized queuing model simulation of store-and-forward computer communication networks is developed and implemented using Simulation Language for Alternative Modeling (SLAM). A baseline simulation model is validated by comparison with published analytic models. The baseline model is expanded to include an ACK/NAK data link protocol, four-level message precedence, finite queues, and a response traffic scenario. Network performance, as indicated by average message delay and message throughput, is estimated using the simulation model.

  19. The Deep Space Network. [tracking and communication functions and facilities

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The objectives, functions, and organization of the Deep Space Network are summarized. The Deep Space Instrumentation Facility, the Ground Communications Facility, and the Network Control System are described.

  20. Networked sensor communications for the objective force

    NASA Astrophysics Data System (ADS)

    Nemeroff, Jay L.; Garcia, Luis; Hampel, Daniel; DiPierro, Stefano

    2002-08-01

    The US Army's Future Combat Systems (FCS) and Objective Force will rely heavily on the use of unattended sensor networks to detect, locate and identify enemy targets in order to survive with less armor protection on the future battlefield. Successful implementation of these critical communication networks will require the collection of the sensor data, processing and collating it with available intelligence, then transporting it in a format conducive to make quick and accurate command decisions based on the latest tactical situational awareness. The networked communications must support both static deployed and mobile ground and air robotic sensors with secure, stealthy, and jam resistant links for sensor fusion and command and control. It is envisioned for broadest application that sensor networks can be deployed in a two-tiered architecture. The architecture includes a lower sensor sub- layer consisting of mixes of acoustic, magnetic and seismic detectors and an upper sub-layer consisting of infrared or visual imagers. The upper sub-layer can be cued by the lower sub-layer and provides a gateway link to the higher echelon tactical maneuver layer networks such as the Tactical Internet. The sensor deployments, networking constraints and reach back distances to Command and Control (C2) nodes will be mission scenario specific, however, the architecture will also apply to tactical unattended sensor, munition and robotic application. Technologies from the Army Research Laboratory, Defense Research Projects Agency (DARPA), and commercial will be leveraged for this effort.

  1. Networked sensor communications for the objective force

    NASA Astrophysics Data System (ADS)

    Nemeroff, Jay L.; Garcia, Luis; Hampel, Daniel; Di Pierro, Stefano

    2002-08-01

    The US Army's Future Combat Systems (FCS) and Objective Force will rely heavily on the use of unattended sensor networks to detect, locate and identify enemy targets in order to survive with less armor protection on the future battlefield. Successful implementation of these critical communication networks will require the collection of the sensor data, processing and collating it with available intelligence, then transporting it in a format conducive to make quick and accurate command decisions based on the latest tactical situational awareness. The networked communications must support both static deployed and mobile ground and air robotic sensors with secure, stealthy, and jam resistant links for sensor fusion and command and control. It is envisioned for broadest application that sensor networks can be deployed in a two-tiered architecture. The architecture includes a lower sensor sub-layer consisting of mixes of acoustic, magnetic and seismic detectors and an upper sub-layer consisting of infrared or visual imagers. The upper sub-layer can be cued by the lower sub-layer and provides a gateway link to the higher echelon tactical maneuver layer networks such as the Tactical Internet. The sensor deployments, networking constraints and reach back distances to Command and Control (C2) nodes will be mission scenario specific, however, the architecture will also apply to tactical unattended sensor, munition and robotic applications. Technologies from the Army Research Laboratory, Defense Advance Research Projects Agency (DARPA), and commercial will be leveraged for this effort.

  2. Experimental performance evaluation of software defined networking (SDN) based data communication networks for large scale flexi-grid optical networks.

    PubMed

    Zhao, Yongli; He, Ruiying; Chen, Haoran; Zhang, Jie; Ji, Yuefeng; Zheng, Haomian; Lin, Yi; Wang, Xinbo

    2014-04-21

    Software defined networking (SDN) has become the focus in the current information and communication technology area because of its flexibility and programmability. It has been introduced into various network scenarios, such as datacenter networks, carrier networks, and wireless networks. Optical transport network is also regarded as an important application scenario for SDN, which is adopted as the enabling technology of data communication networks (DCN) instead of general multi-protocol label switching (GMPLS). However, the practical performance of SDN based DCN for large scale optical networks, which is very important for the technology selection in the future optical network deployment, has not been evaluated up to now. In this paper we have built a large scale flexi-grid optical network testbed with 1000 virtual optical transport nodes to evaluate the performance of SDN based DCN, including network scalability, DCN bandwidth limitation, and restoration time. A series of network performance parameters including blocking probability, bandwidth utilization, average lightpath provisioning time, and failure restoration time have been demonstrated under various network environments, such as with different traffic loads and different DCN bandwidths. The demonstration in this work can be taken as a proof for the future network deployment. PMID:24787842

  3. Information and Communication: The New Convergence.

    ERIC Educational Resources Information Center

    Beniger, James R.

    1988-01-01

    Discusses the isolation of the field of communications from other disciplines and the inattention of communications to the increasing convergence on information and communication in other disciplines. Maps the convergence by surveying the authors commonly cited in the fields of cognitive science, humanities, and semiotics. (MS)

  4. Lewis Information Network (LINK): Background and overview

    NASA Technical Reports Server (NTRS)

    Schulte, Roger R.

    1987-01-01

    The NASA Lewis Research Center supports many research facilities with many isolated buildings, including wind tunnels, test cells, and research laboratories. These facilities are all located on a 350 acre campus adjacent to the Cleveland Hopkins Airport. The function of NASA-Lewis is to do basic and applied research in all areas of aeronautics, fluid mechanics, materials and structures, space propulsion, and energy systems. These functions require a great variety of remote high speed, high volume data communications for computing and interactive graphic capabilities. In addition, new requirements for local distribution of intercenter video teleconferencing and data communications via satellite have developed. To address these and future communications requirements for the next 15 yrs, a project team was organized to design and implement a new high speed communication system that would handle both data and video information in a common lab-wide Local Area Network. The project team selected cable television broadband coaxial cable technology as the communications medium and first installation of in-ground cable began in the summer of 1980. The Lewis Information Network (LINK) became operational in August 1982 and has become the backbone of all data communications and video.

  5. Topology design and performance analysis of an integrated communication network

    NASA Technical Reports Server (NTRS)

    Li, V. O. K.; Lam, Y. F.; Hou, T. C.; Yuen, J. H.

    1985-01-01

    A research study on the topology design and performance analysis for the Space Station Information System (SSIS) network is conducted. It is begun with a survey of existing research efforts in network topology design. Then a new approach for topology design is presented. It uses an efficient algorithm to generate candidate network designs (consisting of subsets of the set of all network components) in increasing order of their total costs, and checks each design to see if it forms an acceptable network. This technique gives the true cost-optimal network, and is particularly useful when the network has many constraints and not too many components. The algorithm for generating subsets is described in detail, and various aspects of the overall design procedure are discussed. Two more efficient versions of this algorithm (applicable in specific situations) are also given. Next, two important aspects of network performance analysis: network reliability and message delays are discussed. A new model is introduced to study the reliability of a network with dependent failures. For message delays, a collection of formulas from existing research results is given to compute or estimate the delays of messages in a communication network without making the independence assumption. The design algorithm coded in PASCAL is included as an appendix.

  6. Information Networking and Economic Development.

    ERIC Educational Resources Information Center

    McGinn, Howard

    1987-01-01

    Infrastructures and competitiveness are considered in the context of library networking, library service, and economic development in the state of North Carolina. The North Carolina Information Network, a network developed and maintained by the state library and responsive to the needs of the nonlibrary community, is described. (MES)

  7. Cell Multiprocessor Communication Network: Built for Speed

    SciTech Connect

    Kistler, Mike; Perrone, Michael; Petrini, Fabrizio

    2006-06-01

    The existence of major obstacles to the traditional path to processor performance improvement has led chip manufacturers to consider multi-core designs. These architectural solutions promise a variety of power/performance and area/performance benefits. But additional care must be taken to ensure that these benefits are not lost due to inadequate design of the on-chip communication network. This paper presents the design challenges of the on-chip network of the Cell Broadband Engine (Cell BE) processor, and describes in detail its architectural design and the network, communication and synchronization protocols. In the experimental evaluation, performed on an early prototype, we analyze the communication characteristics of the Cell BE processor, using a series of microbenchmarks involving various DMA traffic patterns and synchronization protocols. We find that the on-chip communication subsystem is well matched to the to computational capacity of the processor. A Synergistic Processing Element (SPE) can issue an internal direct memory access (DMA) operation in less than 4 nanoseconds, and a DMA of a single cache line can be executed in less the than 100 nanoseconds. SPEs can achieve the optimal bandwidth of 25.6 GB/second in point to point communication with surprisingly small messages ?only a few KB, using batches of non-blocking DMAs. The aggregate network behavior under heavy load is also remarkably efficient, reaching almost 200 GB/second with collective patterns and optimal contention resolution under hot-spot traffic. Additionally, we demonstrate the consistency of these hardware results with identical experiments carried out using the Mambo simulator software for Cell BE.

  8. A study on a simple communication network by microsats

    NASA Astrophysics Data System (ADS)

    Hashimoto, Yukio; Suzuki, Ryutaro; Miura, Ryu; Kondo, Kimio; Obuchi, Tomoki; Miyazaki, Kazuyoshi; Nakagawa, Osamu; Matsui, Masayasu; Muranaka, Noboru

    1992-03-01

    A concept for a communication network based on the use of microsatellites is advanced in which intersatellite links and onboard digital processing are featured. Voice and digital information are collected from and transferred to 9.6-kbps ground stations and a number of 1.2-kbps single-orbit LEO satellites. The orbits and constellations depend on the system objectives, but the subsystems for the microsatellite network are described in terms of the intersatellite radio link, the satellite bus system, transponder designs, and typical satellite configuration. The target performances for each system are listed including launcher options, stabilization technique, mission payloads, and antenna type. It is suggested that the microsatellite system can reduce time delay for package-message communication and confirm the validity of store and forward mail communication between ground stations and microsatellites.

  9. Performance analysis for gigabit Ethernet communication network under various data rates and switching structures

    NASA Astrophysics Data System (ADS)

    Tsao, Shyh-Lin; Wu, Jun-Yi

    2004-11-01

    This paper reports recent work on gigabit Ethernet interconnection communication traffic analysis. We proposed and demonstrated the system concept of gigabit Ethernet communication. 1.25Gbps, 10Gpbs and 40Gpbs gigabit Ethernet interconnection networks are considered for computer communications. Various switching structures, such as crossbar, double crossbar (Dcrossbar), Modified Dilated Benes (MDB), General MDB (GMDB), Benes, Dilated Benes (Dbenes), Tree architecture, Simplified tree (Stree), Extended baseline network (Ebaseline) are analyzed for searching the optimal performance of gigabit Ethernet communication. The numerical results for computation information transferring can be applied to search a best strategy for gigabit Ethernet communication networks interconnections.

  10. Apparatus and method for data communication in an energy distribution network

    DOEpatents

    Hussain, Mohsin; LaPorte, Brock; Uebel, Udo; Zia, Aftab

    2014-07-08

    A system for communicating information on an energy distribution network is disclosed. In one embodiment, the system includes a local supervisor on a communication network, wherein the local supervisor can collect data from one or more energy generation/monitoring devices. The system also includes a command center on the communication network, wherein the command center can generate one or more commands for controlling the one or more energy generation devices. The local supervisor can periodically transmit a data signal indicative of the data to the command center via a first channel of the communication network at a first interval. The local supervisor can also periodically transmit a request for a command to the command center via a second channel of the communication network at a second interval shorter than the first interval. This channel configuration provides effective data communication without a significant increase in the use of network resources.

  11. Position estimation of transceivers in communication networks

    DOEpatents

    Kent, Claudia A.; Dowla, Farid

    2008-06-03

    This invention provides a system and method using wireless communication interfaces coupled with statistical processing of time-of-flight data to locate by position estimation unknown wireless receivers. Such an invention can be applied in sensor network applications, such as environmental monitoring of water in the soil or chemicals in the air where the position of the network nodes is deemed critical. Moreover, the present invention can be arranged to operate in areas where a Global Positioning System (GPS) is not available, such as inside buildings, caves, and tunnels.

  12. NOVANET: communications network for a control system

    SciTech Connect

    Hill, J.R.; Severyn, J.R.; VanArsdall, P.J.

    1983-05-23

    NOVANET is a control system oriented fiber optic local area network that was designed to meet the unique and often conflicting requirements of the Nova laser control system which will begin operation in 1984. The computers and data acquisition devices that form the distributed control system for a large laser fusion research facility need reliable, high speed communications. Both control/status messages and experimental data must be handled. A subset of NOVANET is currently operating on the two beam Novette laser system.

  13. Generalized hypercube structures and hyperswitch communication network

    NASA Technical Reports Server (NTRS)

    Young, Steven D.

    1992-01-01

    This paper discusses an ongoing study that uses a recent development in communication control technology to implement hybrid hypercube structures. These architectures are similar to binary hypercubes, but they also provide added connectivity between the processors. This added connectivity increases communication reliability while decreasing the latency of interprocessor message passing. Because these factors directly determine the speed that can be obtained by multiprocessor systems, these architectures are attractive for applications such as remote exploration and experimentation, where high performance and ultrareliability are required. This paper describes and enumerates these architectures and discusses how they can be implemented with a modified version of the hyperswitch communication network (HCN). The HCN is analyzed because it has three attractive features that enable these architectures to be effective: speed, fault tolerance, and the ability to pass multiple messages simultaneously through the same hyperswitch controller.

  14. Graph analysis of cortical networks reveals complex anatomical communication substrate

    NASA Astrophysics Data System (ADS)

    Zamora-López, Gorka; Zhou, Changsong; Kurths, Jürgen

    2009-03-01

    Sensory information entering the nervous system follows independent paths of processing such that specific features are individually detected. However, sensory perception, awareness, and cognition emerge from the combination of information. Here we have analyzed the corticocortical network of the cat, looking for the anatomical substrate which permits the simultaneous segregation and integration of information in the brain. We find that cortical communications are mainly governed by three topological factors of the underlying network: (i) a large density of connections, (ii) segregation of cortical areas into clusters, and (iii) the presence of highly connected hubs aiding the multisensory processing and integration. Statistical analysis of the shortest paths reveals that, while information is highly accessible to all cortical areas, the complexity of cortical information processing may arise from the rich and intricate alternative paths in which areas can influence each other.

  15. Information, Communication, and Educational Technologies in Rural Alaska

    ERIC Educational Resources Information Center

    Page, G. Andrew; Hill, Melissa

    2008-01-01

    Information, communication, and educational technologies hold promise to connect geographically isolated rural communities, offering adults greater access to educational, financial, and numerous other resources. The Internet and computer-based network technologies are often seen as remedies for communities in economic decline, but they also have…

  16. Organizational Alternatives for a Pacific Educational Computer-Communications Network.

    ERIC Educational Resources Information Center

    Ah Mai, Karen L.

    Organizational alternatives for a Pacific educational computer-communications network are studied through the examples provided by other networks. A survey of networks is provided with a discussion of the history and development of networks and the distinctions in network technology and applications. Nine specific networks are described. Libraries…

  17. Traffic analysis of a medical multimedia communication network

    NASA Astrophysics Data System (ADS)

    Zoupas, Vasilios; Kotsopoulos, Stavros A.; Lymberopoulos, Dimitris C.

    1993-09-01

    Within the framework of the integration of medical information environment (MIE), special groupware multimedia services (GMS) should be developed. The application of GMSs to specially designed medical communication networks (MCN) creates an integrated user collaboration scheme for supporting and handling special medical cases. The present paper deals with the study and analysis of the traffic performance of a private multimedia ISDN MCN with a dynamic bandwidth allocation.

  18. Community detection based on network communicability

    NASA Astrophysics Data System (ADS)

    Estrada, Ernesto

    2011-03-01

    We propose a new method for detecting communities based on the concept of communicability between nodes in a complex network. This method, designated as N-ComBa K-means, uses a normalized version of the adjacency matrix to build the communicability matrix and then applies K-means clustering to find the communities in a graph. We analyze how this method performs for some pathological cases found in the analysis of the detection limit of communities and propose some possible solutions on the basis of the analysis of the ratio of local to global densities in graphs. We use four different quality criteria for detecting the best clustering and compare the new approach with the Girvan-Newman algorithm for the analysis of two "classical" networks: karate club and bottlenose dolphins. Finally, we analyze the more challenging case of homogeneous networks with community structure, for which the Girvan-Newman completely fails in detecting any clustering. The N-ComBa K-means approach performs very well in these situations and we applied it to detect the community structure in an international trade network of miscellaneous manufactures of metal having these characteristics. Some final remarks about the general philosophy of community detection are also discussed.

  19. GAS MAIN SENSOR AND COMMUNICATIONS NETWORK SYSTEM

    SciTech Connect

    Hagen Schempf, Ph.D.

    2003-02-27

    Automatika, Inc. was contracted by the Department of Energy (DOE) and with co-funding from the New York Gas Group (NYGAS), to develop an in-pipe natural gas prototype measurement and wireless communications system for assessing and monitoring distribution networks. A prototype system was built for low-pressure cast-iron mains and tested in a spider- and serial-network configuration in a live network in Long Island with the support of Keyspan Energy, Inc. The prototype unit combined sensors capable of monitoring pressure, flow, humidity, temperature and vibration, which were sampled and combined in data-packages in an in-pipe master-slave architecture to collect data from a distributed spider-arrangement, and in a master-repeater-slave configuration in serial or ladder-network arrangements. It was found that the system was capable of performing all data-sampling and collection as expected, yielding interesting results as to flow-dynamics and vibration-detection. Wireless in-pipe communications were shown to be feasible and valuable data was collected in order to determine how to improve on range and data-quality in the future.

  20. Testing dimension and nonclassicality in communication networks

    NASA Astrophysics Data System (ADS)

    Bowles, Joseph; Brunner, Nicolas; Pawłowski, Marcin

    2015-08-01

    We consider networks featuring preparation, transformation, and measurement devices, in which devices exchange communication via mediating physical systems. We investigate the problem of testing the dimension of the mediating systems in the device-independent scenario, that is, based on observable data alone. A general framework for tackling this problem is presented, considering both classical and quantum systems. These methods can then also be used to certify the nonclassicality of the mediating systems, given an upper bound on their dimension. Several case studies are reported, which illustrate the relevance of the framework. These examples also show that, for fixed dimension, quantum systems largely outperform classical ones. Moreover, the use of a transformation device considerably improves noise tolerance when compared to simple prepare-and-measure networks. These results suggest that the classical simulation of quantum systems becomes costly in terms of dimension, even for simple networks.

  1. Position Estimation of Tranceivers in Communication Networks

    SciTech Connect

    Kent, C A; Dowla, F U

    2003-10-13

    With the rapid development in wireless sensor networks, there is an important need for transceiver position estimation independent of Global Positioning Systems (GPS) [1,3]. While GPS might be useful for outdoor sensor nodes, it is not for indoor node localization. In this case, position estimation is possible through network range estimates from time-of-flight (TOF) measurements, a technique well suited to large bandwidth physical links, such as in ultra-wideband (UWB) communications. For example, in our UWB systems, with pulse duration less than 200 pico-seconds, range can easily be resolved to less than a foot. Assuming an encoded UWB or spread spectrum physical layer, we developed algorithms and simulation tools to test transceiver position localization. Simulations were designed to lend insight into system characteristics such as position error sensitivities to network geometry, to range estimation errors, and to number of sensor nodes.

  2. Modeling self-organization of communication and topology in Social Networks

    NASA Astrophysics Data System (ADS)

    Sneppen, Kim

    2007-03-01

    We introduce a model of self-organization of communication and topology in social networks with a feedback between different communication habits and the topology. To study this feedback, we let agents communicate to build a perception of a network and use this information to create strategic links. We observe a narrow distribution of links when the communication is low and a system with a broad distribution of links when the communication is high. We also analyze the outcome of chatting, cheating, and lying, as strategies to get better access to information in the network. Chatting, although only adopted by a few agents, gives a global gain in the system. Contrary, in a system with too many liars a global loss is inevitable. References: M. Rosvall and K. Sneppen. ``Modeling self-organization of communication and topology in social networks.'' Phys. Rev. E 74:16108 (2006)

  3. Information transmission and recovery in neural communications channels

    NASA Astrophysics Data System (ADS)

    Eguia, M. C.; Rabinovich, M. I.; Abarbanel, H. D. I.

    2000-11-01

    behavior is strikingly different than the passive role communications channels usually play, and the ``data processing theorem'' of conventional communications theory is violated by these neural channels. Our calculations indicate that neurons can reinforce reliable transmission along a chain even when the synapses and the neurons are not completely reliable components. This phenomenon is generic in parameter space, robust in the presence of noise, and independent of the discretization process. Our results suggest a framework in which one might understand the apparent design complexity of neural information transduction networks. If networks with many dynamical neurons can recover information not apparent at various waystations in the communications channel, such networks may be more robust to noisy signals, may be more capable of communicating many types of encoded sensory neural information, and may be the appropriate design for components, neurons and synapses, which can be individually imprecise, inaccurate ``devices.''

  4. Architecting Communication Network of Networks for Space System of Systems

    NASA Technical Reports Server (NTRS)

    Bhasin, Kul B.; Hayden, Jeffrey L.

    2008-01-01

    The National Aeronautics and Space Administration (NASA) and the Department of Defense (DoD) are planning Space System of Systems (SoS) to address the new challenges of space exploration, defense, communications, navigation, Earth observation, and science. In addition, these complex systems must provide interoperability, enhanced reliability, common interfaces, dynamic operations, and autonomy in system management. Both NASA and the DoD have chosen to meet the new demands with high data rate communication systems and space Internet technologies that bring Internet Protocols (IP), routers, servers, software, and interfaces to space networks to enable as much autonomous operation of those networks as possible. These technologies reduce the cost of operations and, with higher bandwidths, support the expected voice, video, and data needed to coordinate activities at each stage of an exploration mission. In this paper, we discuss, in a generic fashion, how the architectural approaches and processes are being developed and used for defining a hypothetical communication and navigation networks infrastructure to support lunar exploration. Examples are given of the products generated by the architecture development process.

  5. Building a Unified Information Network.

    ERIC Educational Resources Information Center

    Avram, Henriette D.

    1988-01-01

    Discusses cooperative efforts between research organizations and libraries to create a national information network. Topics discussed include the Linked System Project (LSP); technical processing versus reference and research functions; Open Systems Interconnection (OSI) Reference Model; the National Science Foundation Network (NSFNET); and…

  6. World-Wide Information Networks.

    ERIC Educational Resources Information Center

    Samuelson, Kjell A. H. W.

    The future paths of research and development towards world-wide, automated information networks in full operation are examined. From international networked planning and projects under way it appears that exploratory as well as normative approaches have been taken. To some extent adequate technolgical facilities have already come into existence…

  7. Weight-Control Information Network

    MedlinePlus

    ... Research Training & Career Development Grant programs for students, postdocs, and faculty Research at NIDDK Labs, faculty, and ... full list of resources . Alternate Language URL Weight-control Information Network (WIN) Page Content The Weight-control ...

  8. Information Communication Technology (ICT) Shaping Student Affairs.

    ERIC Educational Resources Information Center

    Broughton, Elizabeth

    This paper opens with the following questions: "How prepared are you as a student affairs professional for information communication technology (ICT)? Do you understand such concepts as portals, e-business, Napster, computer use policies, and wireless communication? Will student affairs be shaped by ICT or will student affairs help shape ICT on…

  9. Organization of Communication in Information Systems.

    ERIC Educational Resources Information Center

    Datsenko, V. P.; Zaytsev, N. G.

    Organization of communication between the center of an automated system of information exchange and the subscribers to the system is described. The three requirements are: (1) those technical communication means must be chosen which will provide effective and convenient avenues for calls from the subscribers to the center, (2) the required…

  10. Information Communication Highways in the 1990s: An Analysis of Their Potential Impact on Library Automation.

    ERIC Educational Resources Information Center

    Kibirige, Harry M.

    1991-01-01

    Discussion of the potential effects of fiber optic-based communication technology on information networks and systems design highlights library automation. Topics discussed include computers and telecommunications systems, the importance of information in national economies, microcomputers, local area networks (LANs), national computer networks,…

  11. Reliable Communication Models in Interdependent Critical Infrastructure Networks

    SciTech Connect

    Lee, Sangkeun; Chinthavali, Supriya; Shankar, Mallikarjun

    2016-01-01

    Modern critical infrastructure networks are becoming increasingly interdependent where the failures in one network may cascade to other dependent networks, causing severe widespread national-scale failures. A number of previous efforts have been made to analyze the resiliency and robustness of interdependent networks based on different models. However, communication network, which plays an important role in today's infrastructures to detect and handle failures, has attracted little attention in the interdependency studies, and no previous models have captured enough practical features in the critical infrastructure networks. In this paper, we study the interdependencies between communication network and other kinds of critical infrastructure networks with an aim to identify vulnerable components and design resilient communication networks. We propose several interdependency models that systematically capture various features and dynamics of failures spreading in critical infrastructure networks. We also discuss several research challenges in building reliable communication solutions to handle failures in these models.

  12. Analyzing the Dynamics of Communication in Online Social Networks

    NASA Astrophysics Data System (ADS)

    de Choudhury, Munmun; Sundaram, Hari; John, Ajita; Seligmann, Doree Duncan

    This chapter deals with the analysis of interpersonal communication dynamics in online social networks and social media. Communication is central to the evolution of social systems. Today, the different online social sites feature variegated interactional affordances, ranging from blogging, micro-blogging, sharing media elements (i.e., image, video) as well as a rich set of social actions such as tagging, voting, commenting and so on. Consequently, these communication tools have begun to redefine the ways in which we exchange information or concepts, and how the media channels impact our online interactional behavior. Our central hypothesis is that such communication dynamics between individuals manifest themselves via two key aspects: the information or concept that is the content of communication, and the channel i.e., the media via which communication takes place. We present computational models and discuss large-scale quantitative observational studies for both these organizing ideas. First, we develop a computational framework to determine the "interestingness" property of conversations cented around rich media. Second, we present user models of diffusion of social actions and study the impact of homophily on the diffusion process. The outcome of this research is twofold. First, extensive empirical studies on datasets from YouTube have indicated that on rich media sites, the conversations that are deemed "interesting" appear to have consequential impact on the properties of the social network they are associated with: in terms of degree of participation of the individuals in future conversations, thematic diffusion as well as emergent cohesiveness in activity among the concerned participants in the network. Second, observational and computational studies on large social media datasets such as Twitter have indicated that diffusion of social actions in a network can be indicative of future information cascades. Besides, given a topic, these cascades are often a

  13. Self-organizing hierarchies in sensor and communication networks.

    PubMed

    Prokopenko, Mikhail; Wang, Peter; Valencia, Philip; Price, Don; Foreman, Mark; Farmer, Anthony

    2005-01-01

    We consider a hierarchical multicellular sensing and communication network, embedded in an ageless aerospace vehicle that is expected to detect and react to multiple impacts and damage over a wide range of impact energies. In particular, we investigate self-organization of impact boundaries enclosing critically damaged areas, and impact networks connecting remote cells that have detected noncritical impacts. Each level of the hierarchy is shown to have distinct higher-order emergent properties, desirable in self-monitoring and self-repairing vehicles. In addition, cells and communication messages are shown to need memory (hysteresis) in order to retain desirable emergent behavior within and between various hierarchical levels. Spatiotemporal robustness of self-organizing hierarchies is quantitatively measured with graph-theoretic and information-theoretic techniques, such as the Shannon entropy. This allows us to clearly identify phase transitions separating chaotic dynamics from ordered and robust patterns. PMID:16197671

  14. Network Information Management Subsystem

    NASA Technical Reports Server (NTRS)

    Chatburn, C. C.

    1985-01-01

    The Deep Space Network is implementing a distributed data base management system in which the data are shared among several applications and the host machines are not totally dedicated to a particular application. Since the data and resources are to be shared, the equipment must be operated carefully so that the resources are shared equitably. The current status of the project is discussed and policies, roles, and guidelines are recommended for the organizations involved in the project.

  15. Analysis and improvement of vehicle information sharing networks

    NASA Astrophysics Data System (ADS)

    Gong, Hang; He, Kun; Qu, Yingchun; Wang, Pu

    2016-06-01

    Based on large-scale mobile phone data, mobility demand was estimated and locations of vehicles were inferred in the Boston area. Using the spatial distribution of vehicles, we analyze the vehicle information sharing network generated by the vehicle-to-vehicle (V2V) communications. Although a giant vehicle cluster is observed, the coverage and the efficiency of the information sharing network remain limited. Consequently, we propose a method to extend the information sharing network's coverage by adding long-range connections between targeted vehicle clusters. Furthermore, we employ the optimal design strategy discovered in square lattice to improve the efficiency of the vehicle information sharing network.

  16. GAS MAIN SENSOR AND COMMUNICATIONS NETWORK SYSTEM

    SciTech Connect

    Hagen Schempf

    2004-09-30

    Automatika, Inc. was contracted by the Department of Energy (DOE) and with co-funding from the New York Gas Group (NYGAS), to develop an in-pipe natural gas prototype measurement and wireless communications system for assessing and monitoring distribution networks. In Phase II of this three-phase program, an improved prototype system was built for low-pressure cast-iron and high-pressure steel (including a no-blow installation system) mains and tested in a serial-network configuration in a live network in Long Island with the support of Keyspan Energy, Inc. The experiment was carried out in several open-hole excavations over a multi-day period. The prototype units (3 total) combined sensors capable of monitoring pressure, flow, humidity, temperature and vibration, which were sampled and combined in data-packages in an in-pipe master-repeater-slave configuration in serial or ladder-network arrangements. It was verified that the system was capable of performing all data-sampling, data-storage and collection as expected, yielding interesting results as to flow-dynamics and vibration-detection. Wireless in-pipe communications were shown to be feasible and the system was demonstrated to run off in-ground battery- and above-ground solar power. The remote datalogger access and storage-card features were demonstrated and used to log and post-process system data. Real-time data-display on an updated Phase-I GUI was used for in-field demonstration and troubleshooting.

  17. Essential elements of online information networks on invasive alien species

    USGS Publications Warehouse

    Simpson, A.; Sellers, E.; Grosse, A.; Xie, Y.

    2006-01-01

    In order to be effective, information must be placed in the proper context and organized in a manner that is logical and (preferably) standardized. Recently, invasive alien species (IAS) scientists have begun to create online networks to share their information concerning IAS prevention and control. At a special networking session at the Beijing International Symposium on Biological Invasions, an online Eastern Asia-North American IAS Information Network (EA-NA Network) was proposed. To prepare for the development of this network, and to provide models for other regional collaborations, we compare four examples of global, regional, and national online IAS information networks: the Global Invasive Species Information Network, the Invasives Information Network of the Inter-American Biodiversity Information Network, the Chinese Species Information System, and the Invasive Species Information Node of the US National Biological Information Infrastructure. We conclude that IAS networks require a common goal, dedicated leaders, effective communication, and broad endorsement, in order to obtain sustainable, long-term funding and long-term stability. They need to start small, use the experience of other networks, partner with others, and showcase benefits. Global integration and synergy among invasive species networks will succeed with contributions from both the top-down and the bottom-up. ?? 2006 Springer.

  18. Directory: Information Resources for Human Communication Disorders.

    ERIC Educational Resources Information Center

    National Inst. on Deafness and Other Communications Disorders, Bethesda, MD.

    This directory is designed to encourage networking among individuals and organizations that have an interest in deafness and communication disorders. The main body of the directory includes descriptions and publications of 122 organizations that are national in scope and that focus on health issues relating to hearing, balance, smell, taste,…

  19. Using information networks for competitive advantage.

    PubMed

    Rothenberg, R L

    1995-01-01

    Although the healthcare "information superhighway" has received considerable attention, the use of information technology to create a sustainable competitive advantage is not new to other industries. Economic survival in the new world of managed care may depend on a healthcare delivery system's ability to use network-based communications technologies to differentiate itself in the market, especially through cost savings and demonstration of desirable outcomes. The adaptability of these technologies can help position healthcare organizations to break the paradigms of the past and thrive in a market environment that stresses coordination, efficiency, and quality in various settings. PMID:10146130

  20. Based on asynchronous communication protocol of geographic space information service access mechanism research

    NASA Astrophysics Data System (ADS)

    Chen, G.; Zhao, J.; Gu, M.; Li, D.

    2014-04-01

    At present, the traditional way of accessing to classified network in geographic spatial information services is using network gatekeeper and firewall etc. to ensure public and classified network communications links. However, the physical isolation between classified network and public network is crossed, which is bound to cause classified network potential security hazard. In Yunnan province space Land dynamic monitoring integration project, it proposed the point to point text message communication protocol and asynchronous transmission mechanism. Using geo-spatial information encryption processing and data compression processing method, it reduced the risk of data sensitivity and monitored, namely to ensure data security, which realized geographic spatial information services data communication effectively between classified network and public network in the rigid field conditions.

  1. Workplace Learning in Informal Networks

    ERIC Educational Resources Information Center

    Milligan, Colin; Littlejohn, Allison; Margaryan, Anoush

    2014-01-01

    Learning does not stop when an individual leaves formal education, but becomes increasingly informal, and deeply embedded within other activities such as work. This article describes the challenges of informal learning in knowledge intensive industries, highlighting the important role of personal learning networks. The article argues that…

  2. Mechanisms of Communicating Health Information Through Facebook: Implications for Consumer Health Information Technology Design

    PubMed Central

    Menefee, Hannah K; Thompson, Morgan J; Guterbock, Thomas M; Williams, Ishan C

    2016-01-01

    Background Consumer health information technology (IT) solutions are designed to support patient health management and have the ability to facilitate patients’ health information communication with their social networks. However, there is a need for consumer health IT solutions to align with patients’ health management preferences for increased adoption of the technology. It may be possible to gain an understanding of patients’ needs for consumer health IT supporting their health information communication with social networks by explicating how they have adopted and adapted social networking sites, such as Facebook, for this purpose. Objective Our aim was to characterize patients’ use of all communication mechanisms within Facebook for health information communication to provide insight into how consumer health IT solutions may be better designed to meet patients’ communication needs and preferences. Methods This study analyzed data about Facebook communication mechanisms use from a larger, three-phase, sequential, mixed-methods study. We report here on the results of the study’s first phase: qualitative interviews (N=25). Participants were over 18, used Facebook, were residents or citizens of the United States, spoke English, and had a diagnosis consistent with type 2 diabetes. Participants were recruited through Facebook groups and pages. Participant interviews were conducted via Skype or telephone between July and September 2014. Data analysis was grounded in qualitative content analysis and the initial coding framework was informed by the findings of a previous study. Results Participants’ rationales for the use or disuse of a particular Facebook mechanism to communicate health information reflected six broad themes: (1) characteristics and circumstances of the person, (2) characteristics and circumstances of the relationship, (3) structure and composition of the social network, (4) content of the information, (5) communication purpose, and (6

  3. Gas Main Sensor and Communications Network System

    SciTech Connect

    Hagen Schempf

    2006-05-31

    Automatika, Inc. was contracted by the Department of Energy (DOE) and with co-funding from the Northeast Gas Association (NGA), to develop an in-pipe natural gas prototype measurement and wireless communications system for assessing and monitoring distribution networks. This projected was completed in April 2006, and culminated in the installation of more than 2 dozen GasNet nodes in both low- and high-pressure cast-iron and steel mains owned by multiple utilities in the northeastern US. Utilities are currently logging data (off-line) and monitoring data in real time from single and multiple networked sensors over cellular networks and collecting data using wireless bluetooth PDA systems. The system was designed to be modular, using in-pipe sensor-wands capable of measuring, flow, pressure, temperature, water-content and vibration. Internal antennae allowed for the use of the pipe-internals as a waveguide for setting up a sensor network to collect data from multiple nodes simultaneously. Sensor nodes were designed to be installed with low- and no-blow techniques and tools. Using a multi-drop bus technique with a custom protocol, all electronics were designed to be buriable and allow for on-board data-collection (SD-card), wireless relaying and cellular network forwarding. Installation options afforded by the design included direct-burial and external polemounted variants. Power was provided by one or more batteries, direct AC-power (Class I Div.2) and solar-array. The utilities are currently in a data-collection phase and intend to use the collected (and processed) data to make capital improvement decisions, compare it to Stoner model predictions and evaluate the use of such a system for future expansion, technology-improvement and commercialization starting later in 2006.

  4. The analysis of network transmission method for welding robot information

    NASA Astrophysics Data System (ADS)

    Cheng, Weide; Zhang, Hua; Liu, Donghua; Wang, Hongbo

    2012-01-01

    On the asis of User Datagram Protocol (UserDatagram Protocol, UDP), to do some improvement and design a welding robot network communication protocol (welding robot network communicate protocol: WRNCP), working on the fields of the transport layer and application layer of TCP / IP protocol. According to the characteristics of video data, to design the radio push-type (Broadcast Push Model, BPM) transmission method, improving the efficiency and stability of video transmission.and to designed the network information transmission system, used for real-time control of welding robot network.

  5. The analysis of network transmission method for welding robot information

    NASA Astrophysics Data System (ADS)

    Cheng, Weide; Zhang, Hua; Liu, Donghua; Wang, Hongbo

    2011-12-01

    On the asis of User Datagram Protocol (UserDatagram Protocol, UDP), to do some improvement and design a welding robot network communication protocol (welding robot network communicate protocol: WRNCP), working on the fields of the transport layer and application layer of TCP / IP protocol. According to the characteristics of video data, to design the radio push-type (Broadcast Push Model, BPM) transmission method, improving the efficiency and stability of video transmission.and to designed the network information transmission system, used for real-time control of welding robot network.

  6. Cooperative UAV-Based Communications Backbone for Sensor Networks

    SciTech Connect

    Roberts, R S

    2001-10-07

    The objective of this project is to investigate the use of unmanned air vehicles (UAVs) as mobile, adaptive communications backbones for ground-based sensor networks. In this type of network, the UAVs provide communication connectivity to sensors that cannot communicate with each other because of terrain, distance, or other geographical constraints. In these situations, UAVs provide a vertical communication path for the sensors, thereby mitigating geographic obstacles often imposed on networks. With the proper use of UAVs, connectivity to a widely disbursed sensor network in rugged terrain is readily achieved. Our investigation has focused on networks where multiple cooperating UAVs are used to form a network backbone. The advantage of using multiple UAVs to form the network backbone is parallelization of sensor connectivity. Many widely spaced or isolated sensors can be connected to the network at once using this approach. In these networks, the UAVs logically partition the sensor network into sub-networks (subnets), with one UAV assigned per subnet. Partitioning the network into subnets allows the UAVs to service sensors in parallel thereby decreasing the sensor-to-network connectivity. A UAV services sensors in its subnet by flying a route (path) through the subnet, uplinking data collected by the sensors, and forwarding the data to a ground station. An additional advantage of using multiple UAVs in the network is that they provide redundancy in the communications backbone, so that the failure of a single UAV does not necessarily imply the loss of the network.

  7. An Interdisciplinary Network Making Progress on Climate Change Communication

    NASA Astrophysics Data System (ADS)

    Spitzer, W.; Anderson, J. C.; Bales, S.; Fraser, J.; Yoder, J. A.

    2012-12-01

    , social scientists, Ph.D. students studying oceanography, and staff from more than 20 institutions that teach science to the public came together in these learning groups. Most participants were motivated to create new or revised training or public programs based on lessons learned together. The success of this program rests on a twofold approach that combines collaborative learning with a cognitive and social sciences research based approach to communications. The learning process facilitated trust and experimentation among co-learners to practice applications for communications that has continued beyond the study circle experience through the networks established during the process. Examples drawn from the study circle outputs suggest that this approach could have a transformative impact on informal science education on a broad scale. Ultimately, we envision informal science interpreters as "vectors" for effective science communication, ocean and climate scientists with enhanced communication skills, and increased public demand for explanation and dialogue about global issues.

  8. Exploring the Morphospace of Communication Efficiency in Complex Networks

    PubMed Central

    Goñi, Joaquín; Avena-Koenigsberger, Andrea; Velez de Mendizabal, Nieves; van den Heuvel, Martijn P.; Betzel, Richard F.; Sporns, Olaf

    2013-01-01

    Graph theoretical analysis has played a key role in characterizing global features of the topology of complex networks, describing diverse systems such as protein interactions, food webs, social relations and brain connectivity. How system elements communicate with each other depends not only on the structure of the network, but also on the nature of the system's dynamics which are constrained by the amount of knowledge and resources available for communication processes. Complementing widely used measures that capture efficiency under the assumption that communication preferentially follows shortest paths across the network (“routing”), we define analytic measures directed at characterizing network communication when signals flow in a random walk process (“diffusion”). The two dimensions of routing and diffusion efficiency define a morphospace for complex networks, with different network topologies characterized by different combinations of efficiency measures and thus occupying different regions of this space. We explore the relation of network topologies and efficiency measures by examining canonical network models, by evolving networks using a multi-objective optimization strategy, and by investigating real-world network data sets. Within the efficiency morphospace, specific aspects of network topology that differentially favor efficient communication for routing and diffusion processes are identified. Charting regions of the morphospace that are occupied by canonical, evolved or real networks allows inferences about the limits of communication efficiency imposed by connectivity and dynamics, as well as the underlying selection pressures that have shaped network topology. PMID:23505455

  9. Communication Network Patterns and Employee Performance with New Technology.

    ERIC Educational Resources Information Center

    Papa, Michael J.

    1990-01-01

    Investigates the relationship between employee performance, new technology, employee communication network variables (activity, size, diversity, and integrativeness), and productivity at two corporate offices. Reports significant positive relationships between three of the network variables and employee productivity with new technology. Discusses…

  10. Integrating Information & Communications Technologies into the Classroom

    ERIC Educational Resources Information Center

    Tomei, Lawrence, Ed.

    2007-01-01

    "Integrating Information & Communications Technologies Into the Classroom" examines topics critical to business, computer science, and information technology education, such as: school improvement and reform, standards-based technology education programs, data-driven decision making, and strategic technology education planning. This book also…

  11. Communication and cooperation in underwater acoustic networks

    NASA Astrophysics Data System (ADS)

    Yerramalli, Srinivas

    In this thesis, we present a study of several problems related to underwater point to point communications and network formation. We explore techniques to improve the achievable data rate on a point to point link using better physical layer techniques and then study sensor cooperation which improves the throughput and reliability in an underwater network. Robust point-to-point communications in underwater networks has become increasingly critical in several military and civilian applications related to underwater communications. We present several physical layer signaling and detection techniques tailored to the underwater channel model to improve the reliability of data detection. First, a simplified underwater channel model in which the time scale distortion on each path is assumed to be the same (single scale channel model in contrast to a more general multi scale model). A novel technique, which exploits the nature of OFDM signaling and the time scale distortion, called Partial FFT Demodulation is derived. It is observed that this new technique has some unique interference suppression properties and performs better than traditional equalizers in several scenarios of interest. Next, we consider the multi scale model for the underwater channel and assume that single scale processing is performed at the receiver. We then derive optimized front end pre-processing techniques to reduce the interference caused during single scale processing of signals transmitted on a multi-scale channel. We then propose an improvised channel estimation technique using dictionary optimization methods for compressive sensing and show that significant performance gains can be obtained using this technique. In the next part of this thesis, we consider the problem of sensor node cooperation among rational nodes whose objective is to improve their individual data rates. We first consider the problem of transmitter cooperation in a multiple access channel and investigate the stability of

  12. Quantum Information Theory for Quantum Communication

    NASA Astrophysics Data System (ADS)

    Koashi, Masato

    This chapter gives a concise description of the fundamental concepts of quantum information and quantum communication, which is pertinent to the discussions in the subsequent chapters. Beginning with the basic set of rules that dictate quantum mechanics, the chapter explains the most general ways to describe quantum states, measurements, and state transformations. Convenient mathematical tools are also presented to provide an intuitive picture of a qubit, which is the simplest unit of quantum information. The chapter then elaborates on the distinction between quantum communication and classical communication, with emphasis on the role of quantum entanglement as a communication resource. Quantum teleportation and dense coding are then explained in the context of optimal resource conversions among quantum channels, classical channels, and entanglement.

  13. Time concurrency/phase-time synchronization in digital communications networks

    NASA Technical Reports Server (NTRS)

    Kihara, Masami; Imaoka, Atsushi

    1990-01-01

    Digital communications networks have the intrinsic capability of time synchronization which makes it possible for networks to supply time signals to some applications and services. A practical estimation method for the time concurrency on terrestrial networks is presented. By using this method, time concurrency capability of the Nippon Telegraph and Telephone Corporation (NTT) digital communications network is estimated to be better than 300 ns rms at an advanced level, and 20 ns rms at final level.

  14. Whether information network supplements friendship network

    NASA Astrophysics Data System (ADS)

    Miao, Lili; Zhang, Qian-Ming; Nie, Da-Cheng; Cai, Shi-Min

    2015-02-01

    Homophily is a significant mechanism for link prediction in complex network, of which principle describes that people with similar profiles or experiences tend to tie with each other. In a multi-relationship network, friendship among people has been utilized to reinforce similarity of taste for recommendation system whose basic idea is similar to homophily, yet how the taste inversely affects friendship prediction is little discussed. This paper contributes to address the issue by analyzing two benchmark data sets both including user's behavioral information of taste and friendship based on the principle of homophily. It can be found that the creation of friendship tightly associates with personal taste. Especially, the behavioral information of taste involving with popular objects is much more effective to improve the performance of friendship prediction. However, this result seems to be contradictory to the finding in Zhang et al. (2013) that the behavior information of taste involving with popular objects is redundant in recommendation system. We thus discuss this inconformity to comprehensively understand the correlation between them.

  15. Chain-based communication in cylindrical underwater wireless sensor networks.

    PubMed

    Javaid, Nadeem; Jafri, Mohsin Raza; Khan, Zahoor Ali; Alrajeh, Nabil; Imran, Muhammad; Vasilakos, Athanasios

    2015-01-01

    Appropriate network design is very significant for Underwater Wireless Sensor Networks (UWSNs). Application-oriented UWSNs are planned to achieve certain objectives. Therefore, there is always a demand for efficient data routing schemes, which can fulfill certain requirements of application-oriented UWSNs. These networks can be of any shape, i.e., rectangular, cylindrical or square. In this paper, we propose chain-based routing schemes for application-oriented cylindrical networks and also formulate mathematical models to find a global optimum path for data transmission. In the first scheme, we devise four interconnected chains of sensor nodes to perform data communication. In the second scheme, we propose routing scheme in which two chains of sensor nodes are interconnected, whereas in third scheme single-chain based routing is done in cylindrical networks. After finding local optimum paths in separate chains, we find global optimum paths through their interconnection. Moreover, we develop a computational model for the analysis of end-to-end delay. We compare the performance of the above three proposed schemes with that of Power Efficient Gathering System in Sensor Information Systems (PEGASIS) and Congestion adjusted PEGASIS (C-PEGASIS). Simulation results show that our proposed 4-chain based scheme performs better than the other selected schemes in terms of network lifetime, end-to-end delay, path loss, transmission loss, and packet sending rate. PMID:25658394

  16. Chain-Based Communication in Cylindrical Underwater Wireless Sensor Networks

    PubMed Central

    Javaid, Nadeem; Jafri, Mohsin Raza; Khan, Zahoor Ali; Alrajeh, Nabil; Imran, Muhammad; Vasilakos, Athanasios

    2015-01-01

    Appropriate network design is very significant for Underwater Wireless Sensor Networks (UWSNs). Application-oriented UWSNs are planned to achieve certain objectives. Therefore, there is always a demand for efficient data routing schemes, which can fulfill certain requirements of application-oriented UWSNs. These networks can be of any shape, i.e., rectangular, cylindrical or square. In this paper, we propose chain-based routing schemes for application-oriented cylindrical networks and also formulate mathematical models to find a global optimum path for data transmission. In the first scheme, we devise four interconnected chains of sensor nodes to perform data communication. In the second scheme, we propose routing scheme in which two chains of sensor nodes are interconnected, whereas in third scheme single-chain based routing is done in cylindrical networks. After finding local optimum paths in separate chains, we find global optimum paths through their interconnection. Moreover, we develop a computational model for the analysis of end-to-end delay. We compare the performance of the above three proposed schemes with that of Power Efficient Gathering System in Sensor Information Systems (PEGASIS) and Congestion adjusted PEGASIS (C-PEGASIS). Simulation results show that our proposed 4-chain based scheme performs better than the other selected schemes in terms of network lifetime, end-to-end delay, path loss, transmission loss, and packet sending rate. PMID:25658394

  17. Cheap talk communication with dynamic information searching.

    PubMed

    Zhang, Yongjie; Liu, Yuechen; Feng, Xu

    2016-01-01

    We build an agent-based cheap talk communication model with dynamic information searching behavior. In this model, agent communicates with its neighbors freely to get true or false information. Moreover, the uninformed receivers has ability to break up one link of his neighbor who is considered as a dishonest sender and searches for a new neighbor in the market. We study the impacts of the accuracy of information, the number of neighbors and the percentage of relinking neighbors on the information identification of uninformed receivers. The results suggest that the effect of the accuracy of information and the number of neighbors on information identification is linear, but the effect of the percentage of relinking neighbors presents a first increasing and then decreasing trend. PMID:27375976

  18. Organizational structure and communication networks in a university environment.

    PubMed

    Mathiesen, Joachim; Jamtveit, Bjørn; Sneppen, Kim

    2010-07-01

    The "six degrees of separation" between any two individuals on Earth has become emblematic of the "small world" theme, even though the information conveyed via a chain of human encounters decays very rapidly with increasing chain length, and diffusion of information via this process may be very inefficient in large human organizations. The information flow on a communication network in a large organization, the University of Oslo, has been studied by analyzing email records. The records allow for quantification of communication intensity across organizational levels and between organizational units (referred to as "modules"). We find that the number of email messages within modules scales with module size to the power of 1.29±.06 , and the frequency of communication between individuals decays exponentially with the number of links required upward in the organizational hierarchy before they are connected. Our data also indicates that the number of messages sent by administrative units is proportional to the number of individuals at lower levels in the administrative hierarchy, and the "divergence of information" within modules is associated with this linear relationship. The observed scaling is consistent with a hierarchical system in which individuals far apart in the organization interact little with each other and receive a disproportionate number of messages from higher levels in the administrative hierarchy. PMID:20866686

  19. Modeling And Simulation Of Multimedia Communication Networks

    NASA Astrophysics Data System (ADS)

    Vallee, Richard; Orozco-Barbosa, Luis; Georganas, Nicolas D.

    1989-05-01

    In this paper, we present a simulation study of a browsing system involving radiological image servers. The proposed IEEE 802.6 DQDB MAN standard is designated as the computer network to transfer radiological images from file servers to medical workstations, and to simultaneously support real time voice communications. Storage and transmission of original raster scanned images and images compressed according to pyramid data structures are considered. Different types of browsing as well as various image sizes and bit rates in the DQDB MAN are also compared. The elapsed time, measured from the time an image request is issued until the image is displayed on the monitor, is the parameter considered to evaluate the system performance. Simulation results show that image browsing can be supported by the DQDB MAN.

  20. A Hybrid Satellite-Terrestrial Approach to Aeronautical Communication Networks

    NASA Technical Reports Server (NTRS)

    Kerczewski, Robert J.; Chomos, Gerald J.; Griner, James H.; Mainger, Steven W.; Martzaklis, Konstantinos S.; Kachmar, Brian A.

    2000-01-01

    Rapid growth in air travel has been projected to continue for the foreseeable future. To maintain a safe and efficient national and global aviation system, significant advances in communications systems supporting aviation are required. Satellites will increasingly play a critical role in the aeronautical communications network. At the same time, current ground-based communications links, primarily very high frequency (VHF), will continue to be employed due to cost advantages and legacy issues. Hence a hybrid satellite-terrestrial network, or group of networks, will emerge. The increased complexity of future aeronautical communications networks dictates that system-level modeling be employed to obtain an optimal system fulfilling a majority of user needs. The NASA Glenn Research Center is investigating the current and potential future state of aeronautical communications, and is developing a simulation and modeling program to research future communications architectures for national and global aeronautical needs. This paper describes the primary requirements, the current infrastructure, and emerging trends of aeronautical communications, including a growing role for satellite communications. The need for a hybrid communications system architecture approach including both satellite and ground-based communications links is explained. Future aeronautical communication network topologies and key issues in simulation and modeling of future aeronautical communications systems are described.

  1. Communication networks beyond the capacity crunch

    PubMed Central

    Ellis, A. D.; Suibhne, N. Mac; Saad, D.; Payne, D. N.

    2016-01-01

    This issue of Philosophical Transactions of the Royal Society, Part A represents a summary of the recent discussion meeting ‘Communication networks beyond the capacity crunch’. The purpose of the meeting was to establish the nature of the capacity crunch, estimate the time scales associated with it and to begin to find solutions to enable continued growth in a post-crunch era. The meeting confirmed that, in addition to a capacity shortage within a single optical fibre, many other ‘crunches’ are foreseen in the field of communications, both societal and technical. Technical crunches identified included the nonlinear Shannon limit, wireless spectrum, distribution of 5G signals (front haul and back haul), while societal influences included net neutrality, creative content generation and distribution and latency, and finally energy and cost. The meeting concluded with the observation that these many crunches are genuine and may influence our future use of technology, but encouragingly noted that research and business practice are already moving to alleviate many of the negative consequences. PMID:26809575

  2. Communication networks beyond the capacity crunch.

    PubMed

    Ellis, A D; Mac Suibhne, N; Saad, D; Payne, D N

    2016-03-01

    This issue of Philosophical Transactions of the Royal Society, Part A represents a summary of the recent discussion meeting 'Communication networks beyond the capacity crunch'. The purpose of the meeting was to establish the nature of the capacity crunch, estimate the time scales associated with it and to begin to find solutions to enable continued growth in a post-crunch era. The meeting confirmed that, in addition to a capacity shortage within a single optical fibre, many other 'crunches' are foreseen in the field of communications, both societal and technical. Technical crunches identified included the nonlinear Shannon limit, wireless spectrum, distribution of 5G signals (front haul and back haul), while societal influences included net neutrality, creative content generation and distribution and latency, and finally energy and cost. The meeting concluded with the observation that these many crunches are genuine and may influence our future use of technology, but encouragingly noted that research and business practice are already moving to alleviate many of the negative consequences. PMID:26809575

  3. Communicable Disease Case Entry Using PDAs and Public Wireless Networks

    PubMed Central

    Lober, WB; Bliss, D; Dockrey, MR; Davidson, AJ; Karras, BT

    2003-01-01

    Concerns about detecting and responding to attacks with biowarfare agents have resulted in the development of deployable case reporting systems, e.g. RSVP1. We implement a proof of concept web-based information system to be used securely from personal digital assistants over public wireless networks, by public health field workers for routine and emergent case reporting. The system collects data for a local health jurisdiction, provides content- and event-based notification, and forwards case reports to the Colorado State communicable disease reporting system (CEDRS). We believe this demonstrates a useful integration of portable and web-based technologies with public health practice. PMID:14728422

  4. Information and Communication Using Lasers

    NASA Astrophysics Data System (ADS)

    Alouini, Mehdi; Bretenaker, Fabien

    2015-10-01

    The applications of lasers in industry are numerous. It is of course beyond the scope of this book to give an overview of these applications. Rather than trying and failing in doing so, we have chosen in this chapter to illustrate the unique properties of lasers in four different fields. The two first applications described in this chapter, namely optical telecommunications (Section 3.1) and optical information storage (Section 3.2), highlight the contribution of the spatial coherence of the laser. The third one, namely the ring laser gyroscope (Section 3.3), illustrates the amazing spectral purity that can be provided by laser light. Finally, the fourth one, known under the generic acronym LIDAR (Section 3.4), can use different laser properties, depending on its implementation. It can be based on the laser spatial coherence, the laser temporal coherence, and/or on the laser ability to emit powerful short pulses.

  5. Personal communication in traditional cellular networks

    NASA Astrophysics Data System (ADS)

    Neuer, Ellwood I.

    1996-01-01

    The purpose of this paper is to describe the flow of calls through the mobile network as it applies to the operation of Basic and Enhanced Services. Included in the discussion is the overall network layout, the physical connections between the network entities, and the signaling protocols which allow the entities to be integrated. The specific functionality of the applications and services are not detailed as the specific implementation varies from vendor to vendor and from service provider to service provider. The Enhanced Services Platform is installed in a service providers network in order to offer mobile subscribers services and applications which would otherwise not be available. The service providers' objective is to increase revenue/subscriber, increase subscriber loyalty/decrease churn, and build competitive advantages through differentiation. The services provided on the Enhanced Services platform can be viewed as either Basic or Enhanced. For the purpose of this paper, Basic Services refers to Numeric Paging, Call Answering, and Voice Messaging while Enhanced Services refers to FAX Messaging, One Number Service, Voice Dialing and other Voice Recognition applications, Information Services including FAX on Demand, and Automated Call Routing.

  6. (CICT) Computing, Information, and Communications Technology Overview

    NASA Technical Reports Server (NTRS)

    VanDalsem, William R.

    2003-01-01

    The goal of the Computing, Information, and Communications Technology (CICT) program is to enable NASA's Scientific Research, Space Exploration, and Aerospace Technology Missions with greater mission assurance, for less cost, with increased science return through the development and use of advanced computing, information and communications technologies. This viewgraph presentation includes diagrams of how the political guidance behind CICT is structured. The presentation profiles each part of the NASA Mission in detail, and relates the Mission to the activities of CICT. CICT's Integrated Capability Goal is illustrated, and hypothetical missions which could be enabled by CICT are profiled. CICT technology development is profiled.

  7. The Dynamics of Initiative in Communication Networks

    PubMed Central

    Mollgaard, Anders; Mathiesen, Joachim

    2016-01-01

    Human social interaction is often intermittent. Two acquainted persons can have extended periods without social interaction punctuated by periods of repeated interaction. In this case, the repeated interaction can be characterized by a seed initiative by either of the persons and a number of follow-up interactions. The tendency to initiate social interaction plays an important role in the formation of social networks and is in general not symmetric between persons. In this paper, we study the dynamics of initiative by analysing and modeling a detailed call and text message network sampled from a group of 700 individuals. We show that in an average relationship between two individuals, one part is almost twice as likely to initiate communication compared to the other part. The asymmetry has social consequences and ultimately might lead to the discontinuation of a relationship. We explain the observed asymmetry by a positive feedback mechanism where individuals already taking initiative are more likely to take initiative in the future. In general, people with many initiatives receive attention from a broader spectrum of friends than people with few initiatives. Lastly, we compare the likelihood of taking initiative with the basic personality traits of the five factor model. PMID:27124493

  8. Consensus in networks of mobile communicating agents

    NASA Astrophysics Data System (ADS)

    Baronchelli, Andrea; Díaz-Guilera, Albert

    2012-01-01

    Populations of mobile and communicating agents describe a vast array of technological and natural systems, ranging from sensor networks to animal groups. Here, we investigate how a group-level agreement may emerge in the continuously evolving network defined by the local interactions of the moving individuals. We adopt a general scheme of motion in two dimensions and we let the individuals interact through the minimal naming game, a prototypical scheme to investigate social consensus. We distinguish different regimes of convergence determined by the emission range of the agents and by their mobility, and we identify the corresponding scaling behaviors of the consensus time. In the same way, we rationalize also the behavior of the maximum memory used during the convergence process, which determines the minimum cognitive/storage capacity needed by the individuals. Overall, we believe that the simple and general model presented in this paper can represent a helpful reference for a better understanding of the behavior of populations of mobile agents.

  9. The Dynamics of Initiative in Communication Networks.

    PubMed

    Mollgaard, Anders; Mathiesen, Joachim

    2016-01-01

    Human social interaction is often intermittent. Two acquainted persons can have extended periods without social interaction punctuated by periods of repeated interaction. In this case, the repeated interaction can be characterized by a seed initiative by either of the persons and a number of follow-up interactions. The tendency to initiate social interaction plays an important role in the formation of social networks and is in general not symmetric between persons. In this paper, we study the dynamics of initiative by analysing and modeling a detailed call and text message network sampled from a group of 700 individuals. We show that in an average relationship between two individuals, one part is almost twice as likely to initiate communication compared to the other part. The asymmetry has social consequences and ultimately might lead to the discontinuation of a relationship. We explain the observed asymmetry by a positive feedback mechanism where individuals already taking initiative are more likely to take initiative in the future. In general, people with many initiatives receive attention from a broader spectrum of friends than people with few initiatives. Lastly, we compare the likelihood of taking initiative with the basic personality traits of the five factor model. PMID:27124493

  10. Models, Entropy and Information of Temporal Social Networks

    NASA Astrophysics Data System (ADS)

    Zhao, Kun; Karsai, Márton; Bianconi, Ginestra

    Temporal social networks are characterized by heterogeneous duration of contacts, which can either follow a power-law distribution, such as in face-to-face interactions, or a Weibull distribution, such as in mobile-phone communication. Here we model the dynamics of face-to-face interaction and mobile phone communication by a reinforcement dynamics, which explains the data observed in these different types of social interactions. We quantify the information encoded in the dynamics of these networks by the entropy of temporal networks. Finally, we show evidence that human dynamics is able to modulate the information present in social network dynamics when it follows circadian rhythms and when it is interfacing with a new technology such as the mobile-phone communication technology.

  11. Weight-Control Information Network (WIN)

    MedlinePlus

    ... Feature: Reducing Childhood Obesity The Weight-control Information Network (WIN) Past Issues / Spring - Summer 2010 Table of ... here are tips from the Weight-control Information Network (WIN), an information service of the National Institute ...

  12. Organizational structure and communication networks in a university environment

    NASA Astrophysics Data System (ADS)

    Mathiesen, Joachim; Jamtveit, Bjørn; Sneppen, Kim

    2010-07-01

    The “six degrees of separation” between any two individuals on Earth has become emblematic of the “small world” theme, even though the information conveyed via a chain of human encounters decays very rapidly with increasing chain length, and diffusion of information via this process may be very inefficient in large human organizations. The information flow on a communication network in a large organization, the University of Oslo, has been studied by analyzing email records. The records allow for quantification of communication intensity across organizational levels and between organizational units (referred to as “modules”). We find that the number of email messages within modules scales with module size to the power of 1.29±.06 , and the frequency of communication between individuals decays exponentially with the number of links required upward in the organizational hierarchy before they are connected. Our data also indicates that the number of messages sent by administrative units is proportional to the number of individuals at lower levels in the administrative hierarchy, and the “divergence of information” within modules is associated with this linear relationship. The observed scaling is consistent with a hierarchical system in which individuals far apart in the organization interact little with each other and receive a disproportionate number of messages from higher levels in the administrative hierarchy.

  13. Child Rights Information Network Newsletter, 2000-2002.

    ERIC Educational Resources Information Center

    Khan, Andrea, Ed.; Greenwood, Laura, Ed.

    These five newsletter issues communicate activities of the Child Rights Information Network (CRIN) and report on information resources and world-wide activities concerning children and child rights. The March 2000 issue focuses on children's right to education, assessing the matter form a range of differing perspectives, at international and…

  14. Distributed communications and control network for robotic mining

    NASA Technical Reports Server (NTRS)

    Schiffbauer, William H.

    1989-01-01

    The application of robotics to coal mining machines is one approach pursued to increase productivity while providing enhanced safety for the coal miner. Toward that end, a network composed of microcontrollers, computers, expert systems, real time operating systems, and a variety of program languages are being integrated that will act as the backbone for intelligent machine operation. Actual mining machines, including a few customized ones, have been given telerobotic semiautonomous capabilities by applying the described network. Control devices, intelligent sensors and computers onboard these machines are showing promise of achieving improved mining productivity and safety benefits. Current research using these machines involves navigation, multiple machine interaction, machine diagnostics, mineral detection, and graphical machine representation. Guidance sensors and systems employed include: sonar, laser rangers, gyroscopes, magnetometers, clinometers, and accelerometers. Information on the network of hardware/software and its implementation on mining machines are presented. Anticipated coal production operations using the network are discussed. A parallelism is also drawn between the direction of present day underground coal mining research to how the lunar soil (regolith) may be mined. A conceptual lunar mining operation that employs a distributed communication and control network is detailed.

  15. Social networks and the communication of norms about prenatal care in rural Mexico.

    PubMed

    Lapinski, Maria Knight; Anderson, Jenn; Cruz, Shannon; Lapine, Peter

    2015-01-01

    Many normative beliefs are shared and learned through interpersonal communication, yet research on norms typically focuses on their effects rather than the communication that shapes them. This study focused on interpersonal communication during pregnancy to uncover (a) the nature of pregnancy-related communication and (b) normative information transmitted through such communication. Results from interviews with pregnant women living in rural Mexico revealed limited social networks; often, only a woman's mother or the baby's father were consulted about prenatal care decisions. However, women also indicated that communication with others during pregnancy provided important normative information regarding prenatal care. First, most referents believed that women should receive prenatal care (injunctive norm), which was conceptualized by participants as biomedical, nonmedical, or a blend of both. Second, family members often received prenatal care, whereas friends did not (descriptive norms). These findings highlight the key role of personal and social networks in shaping personal pregnancy-related beliefs and behaviors. PMID:25116348

  16. 75 FR 52508 - Proposed Information Collection; Comment Request; Information and Communication Technology Survey

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-26

    ... Census Bureau Proposed Information Collection; Comment Request; Information and Communication Technology... 2012 Information and Communication Technology Survey (ICTS). The annual survey collects data on two... of information and communication technology equipment and software (computers and...

  17. 78 FR 50374 - Proposed Information Collection; Comment Request; Information and Communication Technology Survey

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-19

    ... Census Bureau Proposed Information Collection; Comment Request; Information and Communication Technology... Bureau plans to conduct the 2013 through 2015 Information and Communication Technology Survey (ICTS). The... leases and rental payments) for four types of information and communication technology equipment...

  18. Using Cellular Communication Networks To Detect Air Pollution.

    PubMed

    David, Noam; Gao, H Oliver

    2016-09-01

    Accurate real time monitoring of atmospheric conditions at ground level is vital for hazard warning, meteorological forecasting, and various environmental applications required for public health and safety. However, conventional monitoring facilities are costly and often insufficient, for example, since they are not representative of the larger space and are not deployed densely enough in the field. There have been numerous scientific works showing the ability of commercial microwave links that comprise the data transmission infrastructure in cellular communication networks to monitor hydrometeors as a potential complementary solution. However, despite the large volume of research carried out in this emerging field during the past decade, no study has shown the ability of the system to provide critical information regarding air quality. Here we reveal the potential for identifying atmospheric conditions prone to air pollution by detecting temperature inversions that trap pollutants at ground level. The technique is based on utilizing standard signal measurements from an existing cellular network during routine operation. PMID:27490182

  19. Artificial neural network for location estimation in wireless communication systems.

    PubMed

    Chen, Chien-Sheng

    2012-01-01

    In a wireless communication system, wireless location is the technique used to estimate the location of a mobile station (MS). To enhance the accuracy of MS location prediction, we propose a novel algorithm that utilizes time of arrival (TOA) measurements and the angle of arrival (AOA) information to locate MS when three base stations (BSs) are available. Artificial neural networks (ANN) are widely used techniques in various areas to overcome the problem of exclusive and nonlinear relationships. When the MS is heard by only three BSs, the proposed algorithm utilizes the intersections of three TOA circles (and the AOA line), based on various neural networks, to estimate the MS location in non-line-of-sight (NLOS) environments. Simulations were conducted to evaluate the performance of the algorithm for different NLOS error distributions. The numerical analysis and simulation results show that the proposed algorithms can obtain more precise location estimation under different NLOS environments. PMID:22736978

  20. [Forensic evidence-based medicine in computer communication networks].

    PubMed

    Qiu, Yun-Liang; Peng, Ming-Qi

    2013-12-01

    As an important component of judicial expertise, forensic science is broad and highly specialized. With development of network technology, increasement of information resources, and improvement of people's legal consciousness, forensic scientists encounter many new problems, and have been required to meet higher evidentiary standards in litigation. In view of this, evidence-based concept should be established in forensic medicine. We should find the most suitable method in forensic science field and other related area to solve specific problems in the evidence-based mode. Evidence-based practice can solve the problems in legal medical field, and it will play a great role in promoting the progress and development of forensic science. This article reviews the basic theory of evidence-based medicine and its effect, way, method, and evaluation in the forensic medicine in order to discuss the application value of forensic evidence-based medicine in computer communication networks. PMID:24665620

  1. Effective Chemistry Communication in Informal Environments

    ERIC Educational Resources Information Center

    National Academies Press, 2016

    2016-01-01

    Chemistry plays a critical role in daily life, impacting areas such as medicine and health, consumer products, energy production, the ecosystem, and many other areas. Communicating about chemistry in informal environments has the potential to raise public interest and understanding of chemistry around the world. However, the chemistry community…

  2. School Leadership and Information Communication Technology

    ERIC Educational Resources Information Center

    Afshari, Mojgan; Bakar, Kamariah Abu; Luan, Wong Su; Samah, Bahaman Abu; Fooi, Foo Say

    2008-01-01

    Leadership is an important component in guiding the teaching-learning process. Principal as school leaders have a major responsibility for initiating and implementing school change through the use of Information and Communication Technology (ICT) and can facilitate complex decision to integrate it into learning, teaching and school administration.…

  3. Information Communication Technology Planning in Developing Countries

    ERIC Educational Resources Information Center

    Malapile, Sandy; Keengwe, Jared

    2014-01-01

    This article explores major issues related to Information Communication Technology (ICT) in education and technology planning. Using the diffusion of innovation theory, the authors examine technology planning opportunities and challenges in Developing countries (DCs), technology planning trends in schools, and existing technology planning models…

  4. Information, entropy and fidelity in visual communication

    NASA Technical Reports Server (NTRS)

    Huck, Friedrich O.; Fales, Carl L.; Alter-Gartenberg, Rachel; Rahman, Zia-Ur

    1992-01-01

    This paper presents an assessment of visual communication that integrates the critical limiting factors of image gathering and display with the digital processing that is used to code and restore images. The approach focuses on two mathematical criteria, information and fidelity, and on their relationships to the entropy of the encoded data and to the visual quality of the restored image.

  5. Information Network Model Query Processing

    NASA Astrophysics Data System (ADS)

    Song, Xiaopu

    Information Networking Model (INM) [31] is a novel database model for real world objects and relationships management. It naturally and directly supports various kinds of static and dynamic relationships between objects. In INM, objects are networked through various natural and complex relationships. INM Query Language (INM-QL) [30] is designed to explore such information network, retrieve information about schema, instance, their attributes, relationships, and context-dependent information, and process query results in the user specified form. INM database management system has been implemented using Berkeley DB, and it supports INM-QL. This thesis is mainly focused on the implementation of the subsystem that is able to effectively and efficiently process INM-QL. The subsystem provides a lexical and syntactical analyzer of INM-QL, and it is able to choose appropriate evaluation strategies and index mechanism to process queries in INM-QL without the user's intervention. It also uses intermediate result structure to hold intermediate query result and other helping structures to reduce complexity of query processing.

  6. A cross-domain communication resource scheduling method for grid-enabled communication networks

    NASA Astrophysics Data System (ADS)

    Zheng, Xiangquan; Wen, Xiang; Zhang, Yongding

    2011-10-01

    To support a wide range of different grid applications in environments where various heterogeneous communication networks coexist, it is important to enable advanced capabilities in on-demand and dynamical integration and efficient co-share with cross-domain heterogeneous communication resource, thus providing communication services which are impossible for single communication resource to afford. Based on plug-and-play co-share and soft integration with communication resource, Grid-enabled communication network is flexibly built up to provide on-demand communication services for gird applications with various requirements on quality of service. Based on the analysis of joint job and communication resource scheduling in grid-enabled communication networks (GECN), this paper presents a cross multi-domain communication resource cooperatively scheduling method and describes the main processes such as traffic requirement resolution for communication services, cross multi-domain negotiation on communication resource, on-demand communication resource scheduling, and so on. The presented method is to afford communication service capability to cross-domain traffic delivery in GECNs. Further research work towards validation and implement of the presented method is pointed out at last.

  7. Space Station Information System requirements for integrated communications

    NASA Technical Reports Server (NTRS)

    Marker, W.; Whitelaw, V.; Muratore, J.; Bigham, J., Jr.

    1987-01-01

    Space Station Information System (SSIS) requirements for integrated end-to-end communications are presented. The SSIS is defined as the integrated set of space and ground data and information systems and networks which will provide required data services to the Space Station flight crew, ground operations personnel, and customer communities. This model is based on the International Standards Organization (ISO) layered model for Open System Interconnection (OSI). These SSIS requirements include grades of service, priority classifications, systems management, flow control, bandwidth allocation, and standard SSIS data services.

  8. Robust Networking Architecture and Secure Communication Scheme for Heterogeneous Wireless Sensor Networks

    ERIC Educational Resources Information Center

    McNeal, McKenzie, III.

    2012-01-01

    Current networking architectures and communication protocols used for Wireless Sensor Networks (WSNs) have been designed to be energy efficient, low latency, and long network lifetime. One major issue that must be addressed is the security in data communication. Due to the limited capabilities of low cost and small sized sensor nodes, designing…

  9. 47 CFR 64.2005 - Use of customer proprietary network information without customer approval.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 3 2011-10-01 2011-10-01 false Use of customer proprietary network information without customer approval. 64.2005 Section 64.2005 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2005 Use of customer proprietary network information without...

  10. 47 CFR 64.2005 - Use of customer proprietary network information without customer approval.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Use of customer proprietary network information without customer approval. 64.2005 Section 64.2005 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2005 Use of customer proprietary network information without...

  11. 47 CFR 64.2011 - Notification of customer proprietary network information security breaches.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Notification of customer proprietary network information security breaches. 64.2011 Section 64.2011 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2011 Notification of customer proprietary network information...

  12. 47 CFR 64.2011 - Notification of customer proprietary network information security breaches.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 3 2011-10-01 2011-10-01 false Notification of customer proprietary network information security breaches. 64.2011 Section 64.2011 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2011 Notification of customer proprietary network information...

  13. 47 CFR 64.2011 - Notification of customer proprietary network information security breaches.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 3 2014-10-01 2014-10-01 false Notification of customer proprietary network information security breaches. 64.2011 Section 64.2011 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2011 Notification of customer proprietary network information...

  14. The Virtual Research and Extension Communication Network (VRECN): An Interactive Learning and Communication Network for Research and Extension Personnel. Concept Paper for the Food & Agriculture Organisation of the United Nations (FAO).

    ERIC Educational Resources Information Center

    Richardson, Don

    A Virtual Research and Extension Communication Network (VRECN) is a set of networked electronic tools facilitating improvement in communication processes and information sharing among stakeholders involved in agricultural development. In developing countries, research and extension personnel within a ministry of agriculture, in consultation and…

  15. Extensible query processing and data communication in geoscientific information systems

    NASA Astrophysics Data System (ADS)

    Shek, Eddie Chi-Ho

    Research interest in geoscientific data management, processing, and dissemination has significantly increased over the last few years. Geoscientific applications are characterized by the massive size and spatio-temporal nature of their datasets, as well as the complexity and variety of their operations. In this dissertation, we study issues concerning data modeling, query processing, and data communication in an extensible distributed information system designed to satisfy the requirements imposed by the characteristics of geoscientific applications. Data model and computation architecture form the basis of an information system. It is important that they fit the requirements imposed by the application to be supported. We define a conceptually simple yet expressive scientific data modeling framework, called the Field data model, that captures the structure of a wide variety of scientific and traditional data structures. In addition, it models a number of common higher-order scientific computation patterns hence allowing application-specific operations fitting these patterns to be naturally and seamless introduced. Parallel evaluation is one of the most effective approaches to deliver high query performance. At the same time, geoscientific information systems have to be extensible to accommodate user-defined application-specific operations. To support extensibility in parallel query optimization, we introduce a model that allows the implicit parallelism available in scientific operations to be declaratively captured. Query parallelism algorithms are developed to demonstrate how these information can be exploited to systematically generate efficient parallel query execution plans. The cost of data communication in a scientific information system can be expensive despite the advancement of networking technology, especially during the delivery of data to user over a wide-area network such as the Internet. We present a flexible object-oriented framework called FALCON to

  16. The network and transmission of based on the principle of laser multipoint communication

    NASA Astrophysics Data System (ADS)

    Fu, Qiang; Liu, Xianzhu; Jiang, Huilin; Hu, Yuan; Jiang, Lun

    2014-11-01

    Space laser communication is the perfectly choose to the earth integrated information backbone network in the future. This paper introduces the structure of the earth integrated information network that is a large capacity integrated high-speed broadband information network, a variety of communications platforms were densely interconnected together, such as the land, sea, air and deep air users or aircraft, the technologies of the intelligent high-speed processing, switching and routing were adopt. According to the principle of maximum effective comprehensive utilization of information resources, get accurately information, fast processing and efficient transmission through inter-satellite, satellite earth, sky and ground station and other links. Namely it will be a space-based, air-based and ground-based integrated information network. It will be started from the trends of laser communication. The current situation of laser multi-point communications were expounded, the transmission scheme of the dynamic multi-point between wireless laser communication n network has been carefully studied, a variety of laser communication network transmission schemes the corresponding characteristics and scope described in detail , described the optical multiplexer machine that based on the multiport form of communication is applied to relay backbone link; the optical multiplexer-based on the form of the segmentation receiver field of view is applied to small angle link, the optical multiplexer-based form of three concentric spheres structure is applied to short distances, motorized occasions, and the multi-point stitching structure based on the rotation paraboloid is applied to inter-satellite communications in detail. The multi-point laser communication terminal apparatus consist of the transmitting and receiving antenna, a relay optical system, the spectroscopic system, communication system and communication receiver transmitter system. The communication forms of optical

  17. Information Security and Privacy in Network Environments.

    ERIC Educational Resources Information Center

    Congress of the U.S., Washington, DC. Office of Technology Assessment.

    The use of information networks for business and government is expanding enormously. Government use of networks features prominently in plans to make government more efficient, effective, and responsive. But the transformation brought about by the networking also raises new concerns for the security and privacy of networked information. This…

  18. A novel approach to characterize information radiation in complex networks

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoyang; Wang, Ying; Zhu, Lin; Li, Chao

    2016-06-01

    The traditional research of information dissemination is mostly based on the virus spreading model that the information is being spread by probability, which does not match very well to the reality, because the information that we receive is always more or less than what was sent. In order to quantitatively describe variations in the amount of information during the spreading process, this article proposes a safety information radiation model on the basis of communication theory, combining with relevant theories of complex networks. This model comprehensively considers the various influence factors when safety information radiates in the network, and introduces some concepts from the communication theory perspective, such as the radiation gain function, receiving gain function, information retaining capacity and information second reception capacity, to describe the safety information radiation process between nodes and dynamically investigate the states of network nodes. On a micro level, this article analyzes the influence of various initial conditions and parameters on safety information radiation through the new model simulation. The simulation reveals that this novel approach can reflect the variation of safety information quantity of each node in the complex network, and the scale-free network has better "radiation explosive power", while the small-world network has better "radiation staying power". The results also show that it is efficient to improve the overall performance of network security by selecting nodes with high degrees as the information source, refining and simplifying the information, increasing the information second reception capacity and decreasing the noises. In a word, this article lays the foundation for further research on the interactions of information and energy between internal components within complex systems.

  19. Fast quantum communication in linear networks

    NASA Astrophysics Data System (ADS)

    Jacobs, Kurt; Wu, Rebing; Wang, Xiaoting; Ashhab, Sahel; Chen, Qi-Ming; Rabitz, Herschel

    2016-05-01

    Here we consider the speed at which quantum information can be transferred between the nodes of a linear network. Because such nodes are linear oscillators, this speed is also important in the cooling and state preparation of mechanical oscillators, as well as in frequency conversion. We show that if there is no restriction on the size of the linear coupling between two oscillators, then there exist control protocols that will swap their respective states with high fidelity within a time much shorter than a single oscillation period. Standard gradient search methods fail to find these fast protocols. We were able to do so by augmenting standard search methods with a path-tracing technique, demonstrating that this technique has remarkable power to solve time-optimal control problems, as well as confirming the highly challenging nature of these problems. As a further demonstration of the power of path tracing, first introduced by Moore Tibbets et al. (Phys. Rev. A, 86 (2012) 062309), we apply it to the generation of entanglement in a linear network.

  20. Statistically validated mobile communication networks: the evolution of motifs in European and Chinese data

    NASA Astrophysics Data System (ADS)

    Li, Ming-Xia; Palchykov, Vasyl; Jiang, Zhi-Qiang; Kaski, Kimmo; Kertész, János; Miccichè, Salvatore; Tumminello, Michele; Zhou, Wei-Xing; Mantegna, Rosario N.

    2014-08-01

    Big data open up unprecedented opportunities for investigating complex systems, including society. In particular, communication data serve as major sources for computational social sciences, but they have to be cleaned and filtered as they may contain spurious information due to recording errors as well as interactions, like commercial and marketing activities, not directly related to the social network. The network constructed from communication data can only be considered as a proxy for the network of social relationships. Here we apply a systematic method, based on multiple-hypothesis testing, to statistically validate the links and then construct the corresponding Bonferroni network, generalized to the directed case. We study two large datasets of mobile phone records, one from Europe and the other from China. For both datasets we compare the raw data networks with the corresponding Bonferroni networks and point out significant differences in the structures and in the basic network measures. We show evidence that the Bonferroni network provides a better proxy for the network of social interactions than the original one. Using the filtered networks, we investigated the statistics and temporal evolution of small directed 3-motifs and concluded that closed communication triads have a formation time scale, which is quite fast and typically intraday. We also find that open communication triads preferentially evolve into other open triads with a higher fraction of reciprocated calls. These stylized facts were observed for both datasets.

  1. Advanced Communication and Networking Technologies for Mars Exploration

    NASA Technical Reports Server (NTRS)

    Bhasin, Kul; Hayden, Jeff; Agre, Jonathan R.; Clare, Loren P.; Yan, Tsun-Yee

    2001-01-01

    Next-generation Mars communications networks will provide communications and navigation services to a wide variety of Mars science vehicles including: spacecraft that are arriving at Mars, spacecraft that are entering and descending in the Mars atmosphere, scientific orbiter spacecraft, spacecraft that return Mars samples to Earth, landers, rovers, aerobots, airplanes, and sensing pods. In the current architecture plans, the communication services will be provided using capabilities deployed on the science vehicles as well as dedicated communication satellites that will together make up the Mars network. This network will evolve as additional vehicles arrive, depart or end their useful missions. Cost savings and increased reliability will result from the ability to share communication services between missions. This paper discusses the basic architecture that is needed to support the Mars Communications Network part of NASA's Space Science Enterprise (SSE) communications architecture. The network may use various networking technologies such as those employed in the terrestrial Internet, as well as special purpose deep-space protocols to move data and commands autonomously between vehicles, at disparate Mars vicinity sites (on the surface or in near-Mars space) and between Mars vehicles and earthbound users. The architecture of the spacecraft on-board local communications is being reconsidered in light of these new networking requirements. The trend towards increasingly autonomous operation of the spacecraft is aimed at reducing the dependence on resource scheduling provided by Earth-based operators and increasing system fault tolerance. However, these benefits will result in increased communication and software development requirements. As a result, the envisioned Mars communications infrastructure requires both hardware and protocol technology advancements. This paper will describe a number of the critical technology needs and some of the ongoing research

  2. Information needs for risk management/communication

    SciTech Connect

    Bennett, D.A.

    1990-12-31

    The hazardous waste cleanup program under the Comprehensive Environmental Response, Compensation, and Liability Act (Superfund) is delegated to the ten Regions of the US Environmental Protection Agency (EPA) and has, to date, identified more than 33,000 sites for consideration. The size and complexity of the program places great demands on those who would provide information to achieve national consistency in application of risk assessment while meeting site-specific needs for risk management and risk communication.

  3. Design and analysis of the satellite laser communications network

    NASA Astrophysics Data System (ADS)

    Ren, Pei-an; Qian, Fengchen; Liu, Qiang; Jin, Linlin

    2015-02-01

    A satellite laser communications network structure with two layers and multiple domains has been proposed, which performance has been simulated by OPENT. To simulation, we design several OPNET models of the network's components based on a satellite constellation with two layers and multiple domains, as network model, node model, MAC layer protocol and optical antenna model. The network model consists of core layer and access layer. The core network consists of four geostationary orbit (GEO) satellites which are uniformly distributed in the geostationary orbit. The access network consists of 6 low Earth orbit (LEO) satellites which is the walker delta (walk-δ) constellation with three orbit planes. In access layer, each plane has two satellites, and the constellation is stably. The satellite constellation presented for space laser network can meet the demand of coverage in the middle and low latitude by a few satellites. Also several terminal device models such as the space laser transmitter, receiver, protocol layer module and optical antenna have been designed according to the inter-satellite links in different orbits t from GEO to LEO or GEO to ground. The influence to network of different transmitting throughput, receiving throughput, network protocol and average time delay are simulated. Simulation results of network coverage, connectivity and traffic load performance in different scenes show that the satellite laser network presented by the paper can be fit for high-speed satellite communications. Such analysis can provide effective reference for the research of satellite laser networking and communication protocol.

  4. Optimal Grouping and Matching for Network-Coded Cooperative Communications

    SciTech Connect

    Sharma, S; Shi, Y; Hou, Y T; Kompella, S; Midkiff, S F

    2011-11-01

    Network-coded cooperative communications (NC-CC) is a new advance in wireless networking that exploits network coding (NC) to improve the performance of cooperative communications (CC). However, there remains very limited understanding of this new hybrid technology, particularly at the link layer and above. This paper fills in this gap by studying a network optimization problem that requires joint optimization of session grouping, relay node grouping, and matching of session/relay groups. After showing that this problem is NP-hard, we present a polynomial time heuristic algorithm to this problem. Using simulation results, we show that our algorithm is highly competitive and can produce near-optimal results.

  5. Fiber-Optic Terahertz Data-Communication Networks

    NASA Technical Reports Server (NTRS)

    Chua, Peter L.; Lambert, James L.; Morookian, John M.; Bergman, Larry A.

    1994-01-01

    Network protocols implemented in optical domain. Fiber-optic data-communication networks utilize fully available bandwidth of single-mode optical fibers. Two key features of method: use of subpicosecond laser pulses as carrier signals and spectral phase modulation of pulses for optical implementation of code-division multiple access as multiplexing network protocol. Local-area network designed according to concept offers full crossbar functionality, security of data in transit through network, and capacity about 100 times that of typical fiber-optic local-area network in current use.

  6. Deep Space Network information system architecture study

    NASA Technical Reports Server (NTRS)

    Beswick, C. A.; Markley, R. W. (Editor); Atkinson, D. J.; Cooper, L. P.; Tausworthe, R. C.; Masline, R. C.; Jenkins, J. S.; Crowe, R. A.; Thomas, J. L.; Stoloff, M. J.

    1992-01-01

    The purpose of this article is to describe an architecture for the Deep Space Network (DSN) information system in the years 2000-2010 and to provide guidelines for its evolution during the 1990s. The study scope is defined to be from the front-end areas at the antennas to the end users (spacecraft teams, principal investigators, archival storage systems, and non-NASA partners). The architectural vision provides guidance for major DSN implementation efforts during the next decade. A strong motivation for the study is an expected dramatic improvement in information-systems technologies, such as the following: computer processing, automation technology (including knowledge-based systems), networking and data transport, software and hardware engineering, and human-interface technology. The proposed Ground Information System has the following major features: unified architecture from the front-end area to the end user; open-systems standards to achieve interoperability; DSN production of level 0 data; delivery of level 0 data from the Deep Space Communications Complex, if desired; dedicated telemetry processors for each receiver; security against unauthorized access and errors; and highly automated monitor and control.

  7. Promoting Communication Skills for Information Systems Students in Australian and Portuguese Higher Education: Action Research Study

    ERIC Educational Resources Information Center

    Isaias, Pedro; Issa, Tomayess

    2014-01-01

    This paper aims to examine the value of communication skills learning process through various assessments in Information Systems (IS) postgraduate units in Australia and Portugal. Currently, communication skills are indispensable to students in expanding their social networks and their knowledge at university and in the future workplace, since…

  8. Minimizing communication cost among distributed controllers in software defined networks

    NASA Astrophysics Data System (ADS)

    Arlimatti, Shivaleela; Elbreiki, Walid; Hassan, Suhaidi; Habbal, Adib; Elshaikh, Mohamed

    2016-08-01

    Software Defined Networking (SDN) is a new paradigm to increase the flexibility of today's network by promising for a programmable network. The fundamental idea behind this new architecture is to simplify network complexity by decoupling control plane and data plane of the network devices, and by making the control plane centralized. Recently controllers have distributed to solve the problem of single point of failure, and to increase scalability and flexibility during workload distribution. Even though, controllers are flexible and scalable to accommodate more number of network switches, yet the problem of intercommunication cost between distributed controllers is still challenging issue in the Software Defined Network environment. This paper, aims to fill the gap by proposing a new mechanism, which minimizes intercommunication cost with graph partitioning algorithm, an NP hard problem. The methodology proposed in this paper is, swapping of network elements between controller domains to minimize communication cost by calculating communication gain. The swapping of elements minimizes inter and intra communication cost among network domains. We validate our work with the OMNeT++ simulation environment tool. Simulation results show that the proposed mechanism minimizes the inter domain communication cost among controllers compared to traditional distributed controllers.

  9. Design of Hybrid Mobile Communication Networks for Planetary Exploration

    NASA Technical Reports Server (NTRS)

    Alena, Richard L.; Ossenfort, John; Lee, Charles; Walker, Edward; Stone, Thom

    2004-01-01

    The Mobile Exploration System Project (MEX) at NASA Ames Research Center has been conducting studies into hybrid communication networks for future planetary missions. These networks consist of space-based communication assets connected to ground-based Internets and planetary surface-based mobile wireless networks. These hybrid mobile networks have been deployed in rugged field locations in the American desert and the Canadian arctic for support of science and simulation activities on at least six occasions. This work has been conducted over the past five years resulting in evolving architectural complexity, improved component characteristics and better analysis and test methods. A rich set of data and techniques have resulted from the development and field testing of the communication network during field expeditions such as the Haughton Mars Project and NASA Mobile Agents Project.

  10. The Impact of Network Communication Technology on Science Teacher Education.

    ERIC Educational Resources Information Center

    Sunal, Dennis W.; Sunal, Cynthia Szymanski

    1992-01-01

    Considers the preservice science lesson-planning effects of utilizing local area network (LAN) communication technology across various administrative schemes. Concludes that ease of contact, favorable attitude toward use of technology in communication and teacher education, types of message content, persons contacted, and frequency of…

  11. Networks.

    ERIC Educational Resources Information Center

    Maughan, George R.; Petitto, Karen R.; McLaughlin, Don

    2001-01-01

    Describes the connectivity features and options of modern campus communication and information system networks, including signal transmission (wire-based and wireless), signal switching, convergence of networks, and network assessment variables, to enable campus leaders to make sound future-oriented decisions. (EV)

  12. Technology Developments Integrating a Space Network Communications Testbed

    NASA Technical Reports Server (NTRS)

    Kwong, Winston; Jennings, Esther; Clare, Loren; Leang, Dee

    2006-01-01

    As future manned and robotic space explorations missions involve more complex systems, it is essential to verify, validate, and optimize such systems through simulation and emulation in a low cost testbed environment. The goal of such a testbed is to perform detailed testing of advanced space and ground communications networks, technologies, and client applications that are essential for future space exploration missions. We describe the development of new technologies enhancing our Multi-mission Advanced Communications Hybrid Environment for Test and Evaluation (MACHETE) that enable its integration in a distributed space communications testbed. MACHETE combines orbital modeling, link analysis, and protocol and service modeling to quantify system performance based on comprehensive considerations of different aspects of space missions. It can simulate entire networks and can interface with external (testbed) systems. The key technology developments enabling the integration of MACHETE into a distributed testbed are the Monitor and Control module and the QualNet IP Network Emulator module. Specifically, the Monitor and Control module establishes a standard interface mechanism to centralize the management of each testbed component. The QualNet IP Network Emulator module allows externally generated network traffic to be passed through MACHETE to experience simulated network behaviors such as propagation delay, data loss, orbital effects and other communications characteristics, including entire network behaviors. We report a successful integration of MACHETE with a space communication testbed modeling a lunar exploration scenario. This document is the viewgraph slides of the presentation.

  13. Distributed user-centric scheduling for visible light communication networks.

    PubMed

    Chen, Lingjiao; Wang, Jiaheng; Zhou, Jiantao; Ng, Derrick Wing Kwan; Schober, Robert; Zhao, Chunming

    2016-07-11

    Visible light communication (VLC) networks, consisting of multiple light-emitting diodes (LEDs) acting as optical access points (APs), can provide low-cost high-rate data transmission to multiple users simultaneously in indoor environments. However, the performance of VLC networks is severely limited by the interference between different users. In this paper, we establish a distributed user-centric scheduling framework based on stable marriage theory, and propose a novel decentralized scheduling method to manage interference by forming flexible amorphous cells for all users. The proposed scheduling method has provable low computational complexity and requires only the exchange of a few 1-bit messages between the APs and the users but not the feedback of the channel state information of the entire network. We further show that the proposed method can achieve both user-wise and system-wise optimality as well as a certain level of fairness. Simulation results indicate that our decentralized user-centric scheduling method outperforms existing centralized approaches in terms of throughput, fairness, and computational complexity. PMID:27410830

  14. 47 CFR 64.2008 - Notice required for use of customer proprietary network information.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 3 2011-10-01 2011-10-01 false Notice required for use of customer proprietary network information. 64.2008 Section 64.2008 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2008 Notice required for use of customer proprietary network...

  15. 47 CFR 64.2008 - Notice required for use of customer proprietary network information.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Notice required for use of customer proprietary network information. 64.2008 Section 64.2008 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2008 Notice required for use of customer proprietary network...

  16. 47 CFR 64.2008 - Notice required for use of customer proprietary network information.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 3 2013-10-01 2013-10-01 false Notice required for use of customer proprietary network information. 64.2008 Section 64.2008 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2008 Notice required for use of customer proprietary network...

  17. 47 CFR 64.2008 - Notice required for use of customer proprietary network information.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 3 2012-10-01 2012-10-01 false Notice required for use of customer proprietary network information. 64.2008 Section 64.2008 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2008 Notice required for use of customer proprietary network...

  18. 47 CFR 64.2008 - Notice required for use of customer proprietary network information.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 3 2014-10-01 2014-10-01 false Notice required for use of customer proprietary network information. 64.2008 Section 64.2008 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2008 Notice required for use of customer proprietary network...

  19. Visual communication - Information and fidelity. [of images

    NASA Technical Reports Server (NTRS)

    Huck, Freidrich O.; Fales, Carl L.; Alter-Gartenberg, Rachel; Rahman, Zia-Ur; Reichenbach, Stephen E.

    1993-01-01

    This assessment of visual communication deals with image gathering, coding, and restoration as a whole rather than as separate and independent tasks. The approach focuses on two mathematical criteria, information and fidelity, and on their relationships to the entropy of the encoded data and to the visual quality of the restored image. Past applications of these criteria to the assessment of image coding and restoration have been limited to the link that connects the output of the image-gathering device to the input of the image-display device. By contrast, the approach presented in this paper explicitly includes the critical limiting factors that constrain image gathering and display. This extension leads to an end-to-end assessment theory of visual communication that combines optical design with digital processing.

  20. Network analysis of team communication in a busy emergency department

    PubMed Central

    2013-01-01

    Background The Emergency Department (ED) is consistently described as a high-risk environment for patients and clinicians that demands colleagues quickly work together as a cohesive group. Communication between nurses, physicians, and other ED clinicians is complex and difficult to track. A clear understanding of communications in the ED is lacking, which has a potentially negative impact on the design and effectiveness of interventions to improve communications. We sought to use Social Network Analysis (SNA) to characterize communication between clinicians in the ED. Methods Over three-months, we surveyed to solicit the communication relationships between clinicians at one urban academic ED across all shifts. We abstracted survey responses into matrices, calculated three standard SNA measures (network density, network centralization, and in-degree centrality), and presented findings stratified by night/day shift and over time. Results We received surveys from 82% of eligible participants and identified wide variation in the magnitude of communication cohesion (density) and concentration of communication between clinicians (centralization) by day/night shift and over time. We also identified variation in in-degree centrality (a measure of power/influence) by day/night shift and over time. Conclusions We show that SNA measurement techniques provide a comprehensive view of ED communication patterns. Our use of SNA revealed that frequency of communication as a measure of interdependencies between ED clinicians varies by day/night shift and over time. PMID:23521890

  1. Highly survivable communications: Complementary media packet switched networks

    NASA Astrophysics Data System (ADS)

    Yavuz, D.; Eken, F.; Karavassilis, N.

    1994-07-01

    The requirement for highly survivable communications (HSC) for essential command functions in military operations does not need any justification. The ability to communicate under extreme jamming levels and adverse propagation conditions, including high altitude nuclear events, is a very important requirement. There are also many natural disaster related requirements that also need such highly survivable communications. The prevalent and in a sense classical, approach to provide highly assured connectivity can be summarized as follows: Take a particular propagation medium and try to obtain the ultimate performance from it. There are many examples of this philosophy some successful, most not. Our approach, on the other hand, is to use complementary multi-media or mixed-media where communication links utilizing essentially commercial-off-the-shelf (COTS) equipment are integrated using packet radio (PR) techniques. There is also, in our view, an even more fundamental, recently discovered consideration why the expectation of continuous incremental refinement of a system using a given single media may be be achievable. This is derived from the theory of 'deterministic uncertainty' or more popularly known as 'theory of CHAOS', systems whose state space behavior has fractal characteristics. We will elaborate on this novel argument. Complementary multi-media approach has been the focus for all HSC communications activities at STC since 1982. The original STC studies and prototypes were in response to requirements of broadcasting (i.e., one-way transmission) information. A high frequency (HF)/meteorburst (MB) system was developed/prototyped/tested demonstrating the cost effectiveness of the approach. These results are reviewed. More recently, in 1992 STC has completed the development/test of an Open Systems Interconnection (OSI) HF packet radio protocol as no such open or non-proprietary protocol exists. This protocol has been fully tested, documented and made available to

  2. Examining the Evidence: Reflection and Notation in Network Communication.

    ERIC Educational Resources Information Center

    Livingston, Carol C.

    Reflection and notation in communications in the School Renewal Network, a national collegium of practitioners engaged in school reform activities, are examined in this paper. The network was designed to create an interactive knowledge base for school restructuring that would link educators in meaningful dialogue based on research and current…

  3. Toward a Communications Satellite Network for Humanitarian Relief

    NASA Technical Reports Server (NTRS)

    Burleigh, Scott C.; Birrane, Edward J.

    2011-01-01

    Since the introduction in 2008 of the "Ring Road" concept, proposing a communications satellite network designed to support disadvantaged populations, there have been a number of advances in the underlying technologies, CubeSat picosatellites and Delay-Tolerant Networking. We review the original Ring Road proposal, discuss relevant recent technological progress, and offer some tentative notes on projected cost and performance.

  4. An Investigation of the Composition of Interpersonal Communication Networks.

    ERIC Educational Resources Information Center

    Blake, Reed H.

    Drawing on research by the author, this paper analyzes the composition of the interpersonal communication networks (auxiliary channels) which are pervasive in human society. These networks tend to be 1) primary in nature, containing four members from primary relationships and one from a secondary relationship, and 2) reflective of neighborhood and…

  5. Preliminary Evaluation, Texas State Library Communication Network, 1968.

    ERIC Educational Resources Information Center

    Texas State Library, Austin. Field Services Div.

    In 1968 the Texas State Library established a library communications network under Title III of the Librar y Services and Construction Act. The objective of this study was to evaluate the network after six months of operation. Part I of the study consists of a general evaluation by Peat, Marwick, Mitchell and Co., based on operational data…

  6. A Semantic Network Analysis of the International Communication Association.

    ERIC Educational Resources Information Center

    Doerfel, Marya L.; Barnett, George A.

    1999-01-01

    Finds that a semantic network analysis of the International Communication Association (ICA) based on paper titles presented at its 1991 conference had a high degree of correspondence with the affiliation structure. Suggests validity of the procedures employed for determining semantic networks. Interprets results in regard to this journal's…

  7. Communications network design and costing model programmers manual

    NASA Technical Reports Server (NTRS)

    Logan, K. P.; Somes, S. S.; Clark, C. A.

    1983-01-01

    Otpimization algorithms and techniques used in the communications network design and costing model for least cost route and least cost network problems are examined from the programmer's point of view. All system program modules, the data structures within the model, and the files which make up the data base are described.

  8. Information and communication technologies for promoting and sustaining quality of life, health and self-sufficiency in ageing societies--outcomes of the Lower Saxony Research Network Design of Environments for Ageing (GAL).

    PubMed

    Haux, Reinhold; Hein, Andreas; Kolb, Gerald; Künemund, Harald; Eichelberg, Marco; Appell, Jens-E; Appelrath, H-Jürgen; Bartsch, Christian; Bauer, Jürgen M; Becker, Marcus; Bente, Petra; Bitzer, Jörg; Boll, Susanne; Büsching, Felix; Dasenbrock, Lena; Deparade, Riana; Depner, Dominic; Elbers, Katharina; Fachinger, Uwe; Felber, Juliane; Feldwieser, Florian; Forberg, Anne; Gietzelt, Matthias; Goetze, Stefan; Gövercin, Mehmet; Helmer, Axel; Herzke, Tobias; Hesselmann, Tobias; Heuten, Wilko; Huber, Rainer; Hülsken-Giesler, Manfred; Jacobs, Gerold; Kalbe, Elke; Kerling, Arno; Klingeberg, Timo; Költzsch, Yvonne; Lammel-Polchau, Christopher; Ludwig, Wolfram; Marschollek, Michael; Martens, Birger; Meis, Markus; Meyer, Eike Michael; Meyer, Jochen; Meyer Zu Schwabedissen, Hubertus; Moritz, Niko; Müller, Heiko; Nebel, Wolfgang; Neyer, Franz J; Okken, Petra-Karin; Rahe, Julia; Remmers, Hartmut; Rölker-Denker, Lars; Schilling, Meinhard; Schöpke, Birte; Schröder, Jens; Schulze, Gisela C; Schulze, Mareike; Siltmann, Sina; Song, Bianying; Spehr, Jens; Steen, Enno-Edzard; Steinhagen-Thiessen, Elisabeth; Tanschus, Nele-Marie; Tegtbur, Uwe; Thiel, Andreas; Thoben, Wilfried; van Hengel, Peter; Wabnik, Stefan; Wegel, Sandra; Wilken, Olaf; Winkelbach, Simon; Wist, Thorben; Wolf, Klaus-Hendrik; Wolf, Lars; Zokoll-van der Laan, Melanie

    2014-01-01

    Many societies across the world are confronted with demographic changes, usually related to increased life expectancy and, often, relatively low birth rates. Information and communication technologies (ICT) may contribute to adequately support senior citizens in aging societies with respect to quality of life and quality and efficiency of health care processes. For investigating and for providing answers on whether new information and communication technologies can contribute to keeping, or even improving quality of life, health and self-sufficiency in ageing societies through new ways of living and new forms of care, the Lower Saxony Research Network Design of Environments for Ageing (GAL) had been established as a five years research project, running from 2008 to 2013. Ambient-assisted living (AAL) technologies in personal and home environments were especially important. In this article we report on the GAL project, and present some of its major outcomes after five years of research. We report on major challenges and lessons learned in running and organizing such a large, inter- and multidisciplinary project and discuss GAL in the context of related research projects. With respect to research outcomes, we have, for example, learned new knowledge about multimodal and speech-based human-machine-interaction mechanisms for persons with functional restrictions, and identified new methods and developed new algorithms for identifying activities of daily life and detecting acute events, particularly falls. A total of 79 apartments of senior citizens had been equipped with specific "GAL technology", providing new insights into the use of sensor data for smart homes. Major challenges we had to face were to deal constructively with GAL's highly inter- and multidisciplinary aspects, with respect to research into GAL's application scenarios, shifting from theory and lab experimentation to field tests, and the complexity of organizing and, in our view, successfully managing

  9. Local Area Networks for Information Retrieval.

    ERIC Educational Resources Information Center

    Kibirige, Harry M.

    This examination of the use of local area networks (LANs) by libraries summarizes the findings of a nationwide survey of 600 libraries and information centers and 200 microcomputer networking system manufacturers and vendors, which was conducted to determine the relevance of currently available networking systems for library and information center…

  10. Computer-Based Information Networks: Selected Examples.

    ERIC Educational Resources Information Center

    Hardesty, Larry

    The history, purpose, and operation of six computer-based information networks are described in general and nontechnical terms. In the introduction the many definitions of an information network are explored. Ohio College Library Center's network (OCLC) is the first example. OCLC began in 1963, and since early 1973 has been extending its services…

  11. NASCOM network ground communications availability report

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A performance analysis of NASCOM Network circuits is presented. An objective of 99.80 percent availability has been established for all network circuits and an acceptable level of 99.50. A network narrative summary for the current month includes changes in network configurations, current month's totals for modes of service and trouble category losses, a discussion of trends, and significant losses that affected the performance indexes of individual or groups of circuits. A table and narrative summary of those circuits that failed to meet the objective of 99.80% availability for all network circuits and an acceptable level of 99.50. Lost time and interruption tables showing all circuits affected by outages, by trouble category, with their total time and events, scheduled operating hours, and individual availability indexes also are included. Selected circuits whose availabilities have or continue to affect the overall network availability are also analyzed.

  12. Computing, information, and communications: Technologies for the 21. Century

    SciTech Connect

    1998-11-01

    To meet the challenges of a radically new and technologically demanding century, the Federal Computing, Information, and Communications (CIC) programs are investing in long-term research and development (R and D) to advance computing, information, and communications in the United States. CIC R and D programs help Federal departments and agencies to fulfill their evolving missions, assure the long-term national security, better understand and manage the physical environment, improve health care, help improve the teaching of children, provide tools for lifelong training and distance learning to the workforce, and sustain critical US economic competitiveness. One of the nine committees of the National Science and Technology Council (NSTC), the Committee on Computing, Information, and Communications (CCIC)--through its CIC R and D Subcommittee--coordinates R and D programs conducted by twelve Federal departments and agencies in cooperation with US academia and industry. These R and D programs are organized into five Program Component Areas: (1) HECC--High End Computing and Computation; (2) LSN--Large Scale Networking, including the Next Generation Internet Initiative; (3) HCS--High Confidence Systems; (4) HuCS--Human Centered Systems; and (5) ETHR--Education, Training, and Human Resources. A brief synopsis of FY 1997 accomplishments and FY 1998 goals by PCA is presented. This report, which supplements the President`s Fiscal Year 1998 Budget, describes the interagency CIC programs.

  13. Hybrid evolving clique-networks and their communicability

    NASA Astrophysics Data System (ADS)

    Ding, Yimin; Zhou, Bin; Chen, Xiaosong

    2014-08-01

    Aiming to understand real-world hierarchical networks whose degree distributions are neither power law nor exponential, we construct a hybrid clique network that includes both homogeneous and inhomogeneous parts, and introduce an inhomogeneity parameter to tune the ratio between the homogeneous part and the inhomogeneous one. We perform Monte-Carlo simulations to study various properties of such a network, including the degree distribution, the average shortest-path-length, the clustering coefficient, the clustering spectrum, and the communicability.

  14. Space Mobile Network: A Near Earth Communication and Navigation Architecture

    NASA Technical Reports Server (NTRS)

    Israel, Dave J.; Heckler, Greg; Menrad, Robert J.

    2016-01-01

    This paper describes a Space Mobile Network architecture, the result of a recently completed NASA study exploring architectural concepts to produce a vision for the future Near Earth communications and navigation systems. The Space Mobile Network (SMN) incorporates technologies, such as Disruption Tolerant Networking (DTN) and optical communications, and new operations concepts, such as User Initiated Services, to provide user services analogous to a terrestrial smartphone user. The paper will describe the SMN Architecture, envisioned future operations concepts, opportunities for industry and international collaboration and interoperability, and technology development areas and goals.

  15. Novel technology for enhanced security and trust in communication networks

    NASA Astrophysics Data System (ADS)

    Milovanov, Alexander; Bukshpun, Leonid; Pradhan, Ranjit; Jannson, Tomasz

    2011-06-01

    A novel technology that significantly enhances security and trust in wireless and wired communication networks has been developed. It is based on integration of a novel encryption mechanism and novel data packet structure with enhanced security tools. This novel data packet structure results in an unprecedented level of security and trust, while at the same time reducing power consumption and computing/communication overhead in networks. As a result, networks are provided with protection against intrusion, exploitation, and cyber attacks and posses self-building, self-awareness, self-configuring, self-healing, and self-protecting intelligence.

  16. R&D on wireless broadband communication systems: new generation ubiquitous mobile network

    NASA Astrophysics Data System (ADS)

    Ogawa, Hiroyo

    2007-09-01

    R&D on new generation mobile network has attracted a growing interest over the world on the background of rapid market growth for 2nd and 3rd - generation cellular networks and wireless LANs/MANs. The National Institute of Information and Communications Technology (NICT) has been carried out the New Generation Mobile Network Project from April 2002 to March 2006, and has developed fundamental technologies to enable seamless and secure integration of various wireless access networks such as existing cellular networks, wireless LANs, home networks, intelligent transport systems (ITS), the Beyond-3G (B3G) cellular and other wireless access systems. From April 2006, Ubiquitous Mobile Network project focused on cognitive radio technology and integrated seamless networking technology was started. This paper overviews the achievement and the future plan of these projects.

  17. Modeling and Optimizing Space Networks for Improved Communication Capacity

    NASA Astrophysics Data System (ADS)

    Spangelo, Sara C.

    There are a growing number of individual and constellation small satellite missions seeking to download large quantities of science, observation, and surveillance data. The existing ground station infrastructure to support these missions constrains the potential data throughput because the stations are low-cost, are not always available because they are independently owned and operated, and their ability to collect data is often inefficient. The constraints of the small satellite form factor (e.g. mass, size, power) coupled with the ground network limitations lead to significant operational and communication scheduling challenges. Faced with these challenges, our goal is to maximize capacity, defined as the amount of data that is successfully downloaded from space to ground communication nodes. In this thesis, we develop models, tools, and optimization algorithms for spacecraft and ground network operations. First, we develop an analytical modeling framework and a high-fidelity simulation environment that capture the interaction of on-board satellite energy and data dynamics, ground stations, and the external space environment. Second, we perform capacity-based assessments to identify excess and deficient resources for comparison to mission-specific requirements. Third, we formulate and solve communication scheduling problems that maximize communication capacity for a satellite downloading to a network of globally and functionally heterogeneous ground stations. Numeric examples demonstrate the applicability of the models and tools to assess and optimize real-world existing and upcoming small satellite mission scenarios that communicate to global ground station networks as well as generic communication scheduling problem instances. We study properties of optimal satellite communication schedules and sensitivity of communication capacity to various deterministic and stochastic satellite vehicle and network parameters. The models, tools, and optimization techniques we

  18. Power, Avionics and Software Communication Network Architecture

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.; Sands, Obed S.; Bakula, Casey J.; Oldham, Daniel R.; Wright, Ted; Bradish, Martin A.; Klebau, Joseph M.

    2014-01-01

    This document describes the communication architecture for the Power, Avionics and Software (PAS) 2.0 subsystem for the Advanced Extravehicular Mobile Unit (AEMU). The following systems are described in detail: Caution Warn- ing and Control System, Informatics, Storage, Video, Audio, Communication, and Monitoring Test and Validation. This document also provides some background as well as the purpose and goals of the PAS project at Glenn Research Center (GRC).

  19. Enhanced Communication Network Solution for Positive Train Control Implementation

    NASA Technical Reports Server (NTRS)

    Fatehi, M. T.; Simon, J.; Chang, W.; Chow, E. T.; Burleigh, S. C.

    2011-01-01

    The commuter and freight railroad industry is required to implement Positive Train Control (PTC) by 2015 (2012 for Metrolink), a challenging network communications problem. This paper will discuss present technologies developed by the National Aeronautics and Space Administration (NASA) to overcome comparable communication challenges encountered in deep space mission operations. PTC will be based on a new cellular wireless packet Internet Protocol (IP) network. However, ensuring reliability in such a network is difficult due to the "dead zones" and transient disruptions we commonly experience when we lose calls in commercial cellular networks. These disruptions make it difficult to meet PTC s stringent reliability (99.999%) and safety requirements, deployment deadlines, and budget. This paper proposes innovative solutions based on space-proven technologies that would help meet these challenges: (1) Delay Tolerant Networking (DTN) technology, designed for use in resource-constrained, embedded systems and currently in use on the International Space Station, enables reliable communication over networks in which timely data acknowledgments might not be possible due to transient link outages. (2) Policy-Based Management (PBM) provides dynamic management capabilities, allowing vital data to be exchanged selectively (with priority) by utilizing alternative communication resources. The resulting network may help railroads implement PTC faster, cheaper, and more reliably.

  20. Pacific Islands Mass Communications; Selected Information Sources.

    ERIC Educational Resources Information Center

    Richstad, Jim; McMillan, Michael

    1977-01-01

    Presents a bibliography of materials on such area of mass communications in the Pacific Islands as broadcasting, radio and television, cinema, communication research, mass media in education, Honululu Media Council, newspapers and newspapermen, and printing and satellite communication. (JEG)

  1. Efficient data communication protocols for wireless networks

    NASA Astrophysics Data System (ADS)

    Zeydan, Engin

    In this dissertation, efficient decentralized algorithms are investigated for cost minimization problems in wireless networks. For wireless sensor networks, we investigate both the reduction in the energy consumption and throughput maximization problems separately using multi-hop data aggregation for correlated data in wireless sensor networks. The proposed algorithms exploit data redundancy using a game theoretic framework. For energy minimization, routes are chosen to minimize the total energy expended by the network using best response dynamics to local data. The cost function used in routing takes into account distance, interference and in-network data aggregation. The proposed energy-efficient correlation-aware routing algorithm significantly reduces the energy consumption in the network and converges in a finite number of steps iteratively. For throughput maximization, we consider both the interference distribution across the network and correlation between forwarded data when establishing routes. Nodes along each route are chosen to minimize the interference impact in their neighborhood and to maximize the in-network data aggregation. The resulting network topology maximizes the global network throughput and the algorithm is guaranteed to converge with a finite number of steps using best response dynamics. For multiple antenna wireless ad-hoc networks, we present distributed cooperative and regret-matching based learning schemes for joint transmit beanformer and power level selection problem for nodes operating in multi-user interference environment. Total network transmit power is minimized while ensuring a constant received signal-to-interference and noise ratio at each receiver. In cooperative and regret-matching based power minimization algorithms, transmit beanformers are selected from a predefined codebook to minimize the total power. By selecting transmit beamformers judiciously and performing power adaptation, the cooperative algorithm is shown to

  2. Dynamics of rumor-like information dissemination in complex networks

    NASA Astrophysics Data System (ADS)

    Nekovee, Maziar; Moreno, Yamir; Bianconi, Ginestra

    2005-03-01

    An important dynamic process that takes place in complex networks is the spreading of information via rumor-like mechanisms. In addition to their relevance to propagation of rumors and fads in human society, such mechanism are also the basis of an important class of collective communication protocols in complex computer networks, such as the Internet and the peer-to-peer systems. In this talk we present results of our analytical, numerical and large-scale Monte Carlo simulation studies of this process on several classes of complex networks, including random graphs, scale-free networks, and random and small-world topological graphs. Our studies point out to important differences between the dynamics of rumor spreading and that of virus spreading in such networks, and provide new insights into the complex interplay between the spreading phenomena and network topology.

  3. On effectiveness of routing algorithms for satellite communication networks

    NASA Astrophysics Data System (ADS)

    Yu, Wei; Wei, Sixiao; Xu, Guobin; Chen, Genshe; Pham, Khanh; Blasch, Erik P.; Lu, Chao

    2013-05-01

    For worldwide, a satellite communication network is an integral component of the global networking infrastructure. In this paper, we focus on developing effective routing techniques that consider both user preferences and network dynamic conditions. In particular, we develop a weighted-based route selection scheme for the core satellite communication network. Unlike the shortest path routing scheme, our scheme chooses the route from multiple matched entries based on the assigned weights that reflect the dynamic condition of networks. We also discuss how to derive the optimal weights for route assignment. To further meet user's preference, we implement the multiple path routing scheme to achieve the high rate of data transmission and the preemption based routing scheme to guarantee the data transmission for high priority users. Through extensive simulation studies, our data validates the effectiveness of our proposed routing schemes.

  4. Signaling communication events in a computer network

    DOEpatents

    Bender, Carl A.; DiNicola, Paul D.; Gildea, Kevin J.; Govindaraju, Rama K.; Kim, Chulho; Mirza, Jamshed H.; Shah, Gautam H.; Nieplocha, Jaroslaw

    2000-01-01

    A method, apparatus and program product for detecting a communication event in a distributed parallel data processing system in which a message is sent from an origin to a target. A low-level application programming interface (LAPI) is provided which has an operation for associating a counter with a communication event to be detected. The LAPI increments the counter upon the occurrence of the communication event. The number in the counter is monitored, and when the number increases, the event is detected. A completion counter in the origin is associated with the completion of a message being sent from the origin to the target. When the message is completed, LAPI increments the completion counter such that monitoring the completion counter detects the completion of the message. The completion counter may be used to insure that a first message has been sent from the origin to the target and completed before a second message is sent.

  5. NASCOM network: Ground communications reliability report

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A reliability performance analysis of the NASCOM Network circuits is reported. Network performance narrative summary is presented to include significant changes in circuit configurations, current figures, and trends in each trouble category with notable circuit totals specified. Lost time and interruption tables listing circuits which were affected by outages showing their totals category are submitted. A special analysis of circuits with low reliabilities is developed with tables depicting the performance and graphs for individual reliabilities.

  6. Incremental communication for multilayer neural networks: error analysis.

    PubMed

    Ghorbani, A A; Bhavsar, V C

    1998-01-01

    Artificial neural networks (ANNs) involve a large amount of internode communications. To reduce the communication cost as well as the time of learning process in ANNs, we earlier proposed (1995) an incremental internode communication method. In the incremental communication method, instead of communicating the full magnitude of the output value of a node, only the increment or decrement to its previous value is sent to a communication link. In this paper, the effects of the limited precision incremental communication method on the convergence behavior and performance of multilayer neural networks are investigated. The nonlinear aspects of representing the incremental values with reduced (limited) precision for the commonly used error backpropagation training algorithm are analyzed. It is shown that the nonlinear effect of small perturbations in the input(s)/output of a node does not cause instability. The analysis is supported by simulation studies of two problems. The simulation results demonstrate that the limited precision errors are bounded and do not seriously affect the convergence of multilayer neural networks. PMID:18252431

  7. Data communications service by VSAT network in the Philippines

    NASA Astrophysics Data System (ADS)

    Duque, Roberto L.

    Satellite communications is of particular importance to an archipelago like the Philippines. With over 7,100 islands, rugged forests, and mountainous terrain, satellite communications technology offers the opportunity to leapfrog over the existing difficulties associated with terrestrial-based microwave networks. If harnessed correctly, it has the potential to significantly contribute to the provisions of a wide array of services ranging from voice to facsimile and data to video. The continuous evolution of satellite and earth station technology, since its inception more than 30 years ago, has placed within reach technologies which are reliable as well as easily deployed, used, and maintained. The Philippine government's recognition of the vital role of wireless communications was never more evident than during and after the series of natural calamities that hit the country and disrupted existing microwave infrastructure. Aside from obvious technological advantages over conventional communications technologies, satellite communications provides cost-effective solutions and fortifies the country's unstable communications infrastructure.

  8. [Impact of the Internet on communication flow of scientific health information].

    PubMed

    Castro, Regina C Figueiredo

    2006-08-01

    Communication flow of scientific information has been restructured with the development of new technologies and the Internet and their impact on social relations worldwide. The production of scientific knowledge has also been influenced by these cultural, social and economic changes and has contributed to new patterns of scientific communication. The objective of the study was to present the traditional scientific communication model and its evolution to electronic scientific communication stimulated by the use of electronic media and Internet and networking. While the traditional model is based on printed publications, the new one focuses on electronic publishing and open unlimited access to published literature. The challenges faced are in using all the potential of electronic media for improving traditional communication flow of scientific information and defining policies to support the new model of scientific communication to ensure quality, preservation and dissemination of information as a common good. PMID:16924304

  9. A simulation system of grid-enabled communication network capable of joint scheduling of cross-domain communication resources

    NASA Astrophysics Data System (ADS)

    Wen, Xiang; Zheng, Xiangquan

    2011-10-01

    Joint scheduling of cross-domain communication resource based on grid-enabled networking is an efficient solution to better support grid application and provide communication service capability for on-demand cross-domain traffic delivery. This paper presents a grid-enabled communication network simulation system, and carries out study on joint scheduling of cross-domain communication resource in grid-enabled communication network from the point view of feasibility and effectiveness. The result of simulation shows that, by adopting the method of on-demand sharing and flexible composition of communication resource in grid-enable networking, grid application providing quality-guaranteed service could be better supported.

  10. Space-based Networking Technology Developments in the Interplanetary Network Directorate Information Technology Program

    NASA Technical Reports Server (NTRS)

    Clare, Loren; Clement, B.; Gao, J.; Hutcherson, J.; Jennings, E.

    2006-01-01

    Described recent development of communications protocols, services, and associated tools targeted to reduce risk, reduce cost and increase efficiency of IND infrastructure and supported mission operations. Space-based networking technologies developed were: a) Provide differentiated quality of service (QoS) that will give precedence to traffic that users have selected as having the greatest importance and/or time-criticality; b) Improve the total value of information to users through the use of QoS prioritization techniques; c) Increase operational flexibility and improve command-response turnaround; d) Enable new class of networked and collaborative science missions; e) Simplify applications interfaces to communications services; and f) Reduce risk and cost from a common object model and automated scheduling and communications protocols. Technologies are described in three general areas: communications scheduling, middleware, and protocols. Additionally developed simulation environment, which provides comprehensive, quantitative understanding of the technologies performance within overall, evolving architecture, as well as ability to refine & optimize specific components.

  11. Deep Space Network information system architecture study

    NASA Technical Reports Server (NTRS)

    Beswick, C. A.; Markley, R. W. (Editor); Atkinson, D. J.; Cooper, L. P.; Tausworthe, R. C.; Masline, R. C.; Jenkins, J. S.; Crowe, R. A.; Thomas, J. L.; Stoloff, M. J.

    1992-01-01

    The purpose of this article is to describe an architecture for the DSN information system in the years 2000-2010 and to provide guidelines for its evolution during the 1990's. The study scope is defined to be from the front-end areas at the antennas to the end users (spacecraft teams, principal investigators, archival storage systems, and non-NASA partners). The architectural vision provides guidance for major DSN implementation efforts during the next decade. A strong motivation for the study is an expected dramatic improvement in information-systems technologies--i.e., computer processing, automation technology (including knowledge-based systems), networking and data transport, software and hardware engineering, and human-interface technology. The proposed Ground Information System has the following major features: unified architecture from the front-end area to the end user; open-systems standards to achieve interoperability; DSN production of level 0 data; delivery of level 0 data from the Deep Space Communications Complex, if desired; dedicated telemetry processors for each receiver; security against unauthorized access and errors; and highly automated monitor and control.

  12. Network security system for health and medical information using smart IC card

    NASA Astrophysics Data System (ADS)

    Kanai, Yoichi; Yachida, Masuyoshi; Yoshikawa, Hiroharu; Yamaguchi, Masahiro; Ohyama, Nagaaki

    1998-07-01

    A new network security protocol that uses smart IC cards has been designed to assure the integrity and privacy of medical information in communication over a non-secure network. Secure communication software has been implemented as a library based on this protocol, which is called the Integrated Secure Communication Layer (ISCL), and has been incorporated into information systems of the National Cancer Center Hospitals and the Health Service Center of the Tokyo Institute of Technology. Both systems have succeeded in communicating digital medical information securely.

  13. An ultrafast network for communication of radiologic images.

    PubMed

    Stewart, B K; Lou, S L; Wong, W K; Huang, H K

    1991-04-01

    The three most difficult problems in making picture archiving and communication systems (PACS) a clinical reality in radiology are image archiving, very high-resolution display stations, and high-speed networking. This article considers high-speed image transmission through a high-capacity network. Our laboratory has tested several commercially available high-speed networks over the past year. Only one of these networks (UltraNet) has adequate throughput and capacity potential necessary for our PACS. The focus of this experiment is to determine the throughput and capacity characteristics of this star topology networking scheme as they relate to the operation of a PACS in the clinical environment. A large-scale test was done to gauge network performance for three networking configurations modeling those in a PACS: duplex, parallel, and relay. Ten computers used in our PACS (Sun 3 and 4 computers) were connected with UltraNet. For point-to-point throughput (half-duplex model), the network delivers up to 3.1 megabytes/sec for Sun 3 computers and 6.8 megabytes/sec for the Sun Sparcserver 490. As regards capacity considerations (parallel model), five parallel image transfer processes generated a maximum of 13.9 megabytes/sec through the network. Only a slight degradation in individual process throughput was observed (1.4%). With regard to shared access to high-contention resources on the PACS network (e.g., archive servers), this network demonstrated equal sharing of server networking capacity between the various client computers. With the encouraging results of this experiment, we believe that the UltraNet network will be sufficient for the image communication requirements of our PACS. We are proceeding with the implementation of UltraNet as the high-speed backbone of our extended PACS network. PMID:2003451

  14. Tsallis information dimension of complex networks

    NASA Astrophysics Data System (ADS)

    Zhang, Qi; Luo, Chuanhai; Li, Meizhu; Deng, Yong; Mahadevan, Sankaran

    2015-02-01

    The fractal and self-similarity properties are revealed in many complex networks. The information dimension is a useful method to describe the fractal and self-similarity properties of the complex networks. In order to show the influence of different parts in the complex networks to the information dimension, we have proposed a new information dimension based on the Tsallis entropy namely the Tsallis information dimension. The proposed information dimension is changed according to the scale which is described by the nonextensivity parameter q, and it is inverse with the nonextensivity parameter q. The existing information dimension is a special case of the Tsallis information dimension when q = 1. The Tsallis information dimension is a generalized information dimension of the complex networks.

  15. Exploring the Potential of Social Network Sites in Relation to Intercultural Communication

    ERIC Educational Resources Information Center

    Lang, Anouk

    2012-01-01

    This article reports on the results of a project which used a social network site to support students on a year abroad and foster informal learning, particularly in the area of intercultural communication. The project employed a peer-mentoring structure to solve the problem of role conflict, in which users of these sites may feel some tension as…

  16. Social Media and Networking Technologies: An Analysis of Collaborative Work and Team Communication

    ERIC Educational Resources Information Center

    Okoro, Ephraim A.; Hausman, Angela; Washington, Melvin C.

    2012-01-01

    Digital communication increases students' learning outcomes in higher education. Web 2.0 technologies encourages students' active engagement, collaboration, and participation in class activities, facilitates group work, and encourages information sharing among students. Familiarity with organizational use and sharing in social networks aids…

  17. Family Health History Communication Networks of Older Adults: Importance of Social Relationships and Disease Perceptions

    ERIC Educational Resources Information Center

    Ashida, Sato; Kaphingst, Kimberly A.; Goodman, Melody; Schafer, Ellen J.

    2013-01-01

    Older individuals play a critical role in disseminating family health history (FHH) information that can facilitate disease prevention among younger family members. This study evaluated the characteristics of older adults and their familial networks associated with two types of communication ("have shared" and "intend to share…

  18. Novel Quantum Virtual Private Network Scheme for PON via Quantum Secure Direct Communication

    NASA Astrophysics Data System (ADS)

    Gong, Li-Hua; Liu, Ye; Zhou, Nan-Run

    2013-09-01

    Two quantum secure direct communication (QSDC) protocols with quantum identification (QI) based on passive optical network (PON) architecture are proposed. One QSDC protocol can be implemented between two different optical network units just with simple configurations of PON by optical line terminal when they are in the same virtual private network after optical line terminal performing QI to the optical network units in the given PON architecture. The other QSDC protocol is also implemented between any two legitimated users in the virtual private network but with considerable reduction of workload of the optical line terminal. The security analysis shows that the proposed QSDC schemes with quantum identification are unconditionally secure and allow the legitimate users to exchange their secret information efficiently and to realize a quantum virtual private network in the PON networks ultimately.

  19. Software design of optical link for indoor wireless optical communication network used LEDs as source visible light communication

    NASA Astrophysics Data System (ADS)

    Liner, Andrej; Papes, Martin; Jaros, Jakub; Koudelka, Petr; Latal, Jan; Vitasek, Jan; Hajek, Lukas; Vasinek, Vladimir

    2015-01-01

    Nowadays, the conventional light sources are replaced progressively evolving LED (Light Emitting Diode) for their deficient properties. This technology recorded dynamic growth mainly due to effective research in increasing power density and choice the color shade on good color rendering CRI (Color Rendering Index). This extending the zone of used LEDs. Development of lighting technology by means of white power LEDs provided impulse to the idea of the development of optical wireless data networks based on optical radiation in the visible region of the spectrum VLC (Visible Light Communications). In the last years being recorded a turnover of research from transmission of information via optical fiber to the transmission of information through wireless networks. At the same time the concept of information transmission by indirect sight between transmitter and receiver NLOS (Non Line of Sight) is changing. Line of research focuses mainly on the direct line of sight LOS (Line of Sight). This is due to the development of the semiconductor lighting through the white power LED. This is connected with the idea of using them as a transmitter for communication purposes. This article deals with software design of optical link for indoor wireless optical network in LightTools software. Optimal optical source was designed for communication using LED as the first. For the proposed type of LEDs sources were used different shapes and distances distribution between LEDs in a single cell at the designed optical transmitter.

  20. Networked Operations of Hybrid Radio Optical Communications Satellites

    NASA Technical Reports Server (NTRS)

    Hylton, Alan; Raible, Daniel

    2014-01-01

    In order to address the increasing communications needs of modern equipment in space, and to address the increasing number of objects in space, NASA is demonstrating the potential capability of optical communications for both deep space and near-Earth applications. The Integrated Radio Optical Communications (iROC) is a hybrid communications system that capitalizes on the best of both the optical and RF domains while using each technology to compensate for the other's shortcomings. Specifically, the data rates of the optical links can be higher than their RF counterparts, whereas the RF links have greater link availability. The focus of this paper is twofold: to consider the operations of one or more iROC nodes from a networking point of view, and to suggest specific areas of research to further the field. We consider the utility of Disruption Tolerant Networking (DTN) and the Virtual Mission Operation Center (VMOC) model.

  1. The Integration of the Information and Communication Functions, and the Marketing of the Resulting Products.

    ERIC Educational Resources Information Center

    Harris, Susan C.

    1985-01-01

    Discusses the theoretical basis for integration of information functions and communication functions, the relevance of this integration in the scientific information cycle, and its positive effect on commodity research networks. The application of this theory is described using three commodity programs of the Centro Internacional de Agricultura…

  2. The deep space network, volume 18. [Deep Space Instrumentation Facility, Ground Communication Facility, and Network Control System

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The objectives, functions, and organization of the Deep Space Network are summarized. The Deep Space Instrumentation Facility, the Ground Communications Facility, and the Network Control System are described.

  3. Distance Preferences Small-World Communication Topology for Agent Network

    NASA Astrophysics Data System (ADS)

    Wu, Zhengping; Wang, Renming

    In multi-agent system (MAS), the communication topology of agent network plays a very important role in its collaboration. Small-world networks are the networks with high local clustering and small average path length, and the communication networks of MAS can be analyzed within the frame of small-world topology. Yet the real multiagent communication networks are abundant and the classical WS small-world model is not suitable for all cases. In this paper, two new small-world network models are presented. One is based on random graph substrate and local nodes preference reconnection and the other is based on regular graph substrate and long-range nodes preference reconnection. The characteristic of the network parameter such as the clustering coefficients, average path length, and eigenvalue λ2 and λn of the Laplacian matrix for these two models and WS model is studied. The consensus problem that based on these three models is also studied. An example is given and the conclusions are made in the end.

  4. Analysis of adaptive algorithms for an integrated communication network

    NASA Technical Reports Server (NTRS)

    Reed, Daniel A.; Barr, Matthew; Chong-Kwon, Kim

    1985-01-01

    Techniques were examined that trade communication bandwidth for decreased transmission delays. When the network is lightly used, these schemes attempt to use additional network resources to decrease communication delays. As the network utilization rises, the schemes degrade gracefully, still providing service but with minimal use of the network. Because the schemes use a combination of circuit and packet switching, they should respond to variations in the types and amounts of network traffic. Also, a combination of circuit and packet switching to support the widely varying traffic demands imposed on an integrated network was investigated. The packet switched component is best suited to bursty traffic where some delays in delivery are acceptable. The circuit switched component is reserved for traffic that must meet real time constraints. Selected packet routing algorithms that might be used in an integrated network were simulated. An integrated traffic places widely varying workload demands on a network. Adaptive algorithms were identified, ones that respond to both the transient and evolutionary changes that arise in integrated networks. A new algorithm was developed, hybrid weighted routing, that adapts to workload changes.

  5. Predicting Information Flows in Network Traffic.

    ERIC Educational Resources Information Center

    Hinich, Melvin J.; Molyneux, Robert E.

    2003-01-01

    Discusses information flow in networks and predicting network traffic and describes a study that uses time series analysis on a day's worth of Internet log data. Examines nonlinearity and traffic invariants, and suggests that prediction of network traffic may not be possible with current techniques. (Author/LRW)

  6. A 12-transistor PFM demodulator for analog neural networks communication.

    PubMed

    Mortara, A; Vittoz, E A

    1995-01-01

    Pulse frequency modulation (PFM) provides robust long-distance communication and event-driven access to the communication channel. A PFM demodulator small and simple enough to equip every cell of a large analog neural network is analyzed. The circuit can demodulate PFM signals with pulse rates as low as 1 kHz using the switched-capacitor technique. Measurement results from integrated demodulators are presented. PMID:18263418

  7. Network Communication as a Service-Oriented Capability

    SciTech Connect

    Johnston, William; Johnston, William; Metzger, Joe; Collins, Michael; Burrescia, Joseph; Dart, Eli; Gagliardi, Jim; Guok, Chin; Oberman, Kevin; O'Conner, Mike

    2008-01-08

    In widely distributed systems generally, and in science-oriented Grids in particular, software, CPU time, storage, etc., are treated as"services" -- they can be allocated and used with service guarantees that allows them to be integrated into systems that perform complex tasks. Network communication is currently not a service -- it is provided, in general, as a"best effort" capability with no guarantees and only statistical predictability. In order for Grids (and most types of systems with widely distributed components) to be successful in performing the sustained, complex tasks of large-scale science -- e.g., the multi-disciplinary simulation of next generation climate modeling and management and analysis of the petabytes of data that will come from the next generation of scientific instrument (which is very soon for the LHC at CERN) -- networks must provide communication capability that is service-oriented: That is it must be configurable, schedulable, predictable, and reliable. In order to accomplish this, the research and education network community is undertaking a strategy that involves changes in network architecture to support multiple classes of service; development and deployment of service-oriented communication services, and; monitoring and reporting in a form that is directly useful to the application-oriented system so that it may adapt to communications failures. In this paper we describe ESnet's approach to each of these -- an approach that is part of an international community effort to have intra-distributed system communication be based on a service-oriented capability.

  8. Reliability modeling and analysis of communication networks with dependent failures

    NASA Astrophysics Data System (ADS)

    Lam, Y. F.; Li, V. O. K.

    1986-01-01

    This paper presents a new model to study the reliability of communication networks in which link failures are statistically dependent. The approach tries to identify and model explicitly the events that cause communication link failures. No conditional probabilities are needed, and so two major difficulties inherent to them, namely, an exponential number of conditional probabilities to deal with and a consistency requirement to satisfy, are avoided. For reliability computations, some existing algorithms for finding network reliability can be used with minor modifications and no significant increase in computational complexity.

  9. A Secure Communication Suite for Underwater Acoustic Sensor Networks

    PubMed Central

    Dini, Gianluca; Duca, Angelica Lo

    2012-01-01

    In this paper we describe a security suite for Underwater Acoustic Sensor Networks comprising both fixed and mobile nodes. The security suite is composed of a secure routing protocol and a set of cryptographic primitives aimed at protecting the confidentiality and the integrity of underwater communication while taking into account the unique characteristics and constraints of the acoustic channel. By means of experiments and simulations based on real data, we show that the suite is suitable for an underwater networking environment as it introduces limited, and sometimes negligible, communication and power consumption overhead. PMID:23202204

  10. The Social Side of Information Networking.

    ERIC Educational Resources Information Center

    Katz, James E.

    1997-01-01

    Explores the social issues, including manners, security, crime (fraud), and social control associated with information networking, with emphasis on the Internet. Also addresses the influence of cellular phones, the Internet and other information technologies on society. (GR)

  11. Resting-brain functional connectivity predicted by analytic measures of network communication.

    PubMed

    Goñi, Joaquín; van den Heuvel, Martijn P; Avena-Koenigsberger, Andrea; Velez de Mendizabal, Nieves; Betzel, Richard F; Griffa, Alessandra; Hagmann, Patric; Corominas-Murtra, Bernat; Thiran, Jean-Philippe; Sporns, Olaf

    2014-01-14

    The complex relationship between structural and functional connectivity, as measured by noninvasive imaging of the human brain, poses many unresolved challenges and open questions. Here, we apply analytic measures of network communication to the structural connectivity of the human brain and explore the capacity of these measures to predict resting-state functional connectivity across three independently acquired datasets. We focus on the layout of shortest paths across the network and on two communication measures--search information and path transitivity--which account for how these paths are embedded in the rest of the network. Search information is an existing measure of information needed to access or trace shortest paths; we introduce path transitivity to measure the density of local detours along the shortest path. We find that both search information and path transitivity predict the strength of functional connectivity among both connected and unconnected node pairs. They do so at levels that match or significantly exceed path length measures, Euclidean distance, as well as computational models of neural dynamics. This capacity suggests that dynamic couplings due to interactions among neural elements in brain networks are substantially influenced by the broader network context adjacent to the shortest communication pathways. PMID:24379387

  12. RF switch positioner for communications satellite network

    NASA Technical Reports Server (NTRS)

    Storaasli, A. G.; Griesser, H. P.; Grant, R. W.

    1986-01-01

    The RF switch positioner is a simple, lightweight, redundant positioning mechanism used to reconfigure the antenna beam on the INTELSAT VI satellite. It simultaneously rotates approximately 100 squareax waveguide switches through a full 360 deg. The RF switch positioner has been space qualified and has performed to expectations in conjunction with the feed networks in range testing.

  13. Position Estimation of Transceivers in Communication Networks

    SciTech Connect

    Dowla, F; Kent, C

    2004-01-20

    With rapid developments in wireless sensor networks, there is a growing need for transceiver position estimation independent of GPS, which may not be available in indoor networks. Our approach is to use range estimates from time-of-flight (TOF) measurements, a technique well suited to large bandwidth physical links, such as in ultra-wideband (UWB) systems. In our UWB systems, pulse duration less than 200 psecs can easily be resolved to less than a foot. Assuming an encoded UWB physical layer, we first test positioning accuracy using simulations. We are interested in sensitivity to range errors and the required number of ranging nodes, and we show that in a high-precision environment, such as UWB, the optimal number of transmitters is four. Four transmitters with {+-}20ft. range error can locate a receiver to within one or two feet. We then implement these algorithms on an 802.11 wireless network and demonstrate the ability to locate a network access point to approximately 20 feet.

  14. Non-line-of-sight underwater optical wireless communication network.

    PubMed

    Arnon, Shlomi; Kedar, Debbie

    2009-03-01

    The growing need for ocean observation systems has stimulated considerable interest within the research community in advancing the enabling technologies of underwater wireless communication and underwater sensor networks. Sensors and ad hoc sensor networks are the emerging tools for performing extensive data-gathering operations on land, and solutions in the subsea setting are being sought. Efficient communication from the sensors and within the network is critical, but the underwater environment is extremely challenging. Addressing the special features of underwater wireless communication in sensor networks, we propose a novel non-line-of-sight network concept in which the link is implemented by means of back-reflection of the propagating optic signal at the ocean-air interface and derive a mathematical model of the channel. Point-to-multipoint links can be achieved in an energy efficient manner and broadcast broadband communications, such as video transmissions, can be executed. We show achievable bit error rates as a function of sensor node separation and demonstrate the feasibility of this concept using state-of-the-art silicon photomultiplier detectors. PMID:19252651

  15. Simulation of Lunar Surface Communications Network Exploration Scenarios

    NASA Technical Reports Server (NTRS)

    Linsky, Thomas W.; Bhasin, Kul B.; White, Alex; Palangala, Srihari

    2006-01-01

    Simulations and modeling of surface-based communications networks provides a rapid and cost effective means of requirement analysis, protocol assessments, and tradeoff studies. Robust testing in especially important for exploration systems, where the cost of deployment is high and systems cannot be easily replaced or repaired. However, simulation of the envisioned exploration networks cannot be achieved using commercial off the shelf network simulation software. Models for the nonstandard, non-COTS protocols used aboard space systems are not readily available. This paper will address the simulation of realistic scenarios representative of the activities which will take place on the surface of the Moon, including selection of candidate network architectures, and the development of an integrated simulation tool using OPNET modeler capable of faithfully modeling those communications scenarios in the variable delay, dynamic surface environments. Scenarios for exploration missions, OPNET development, limitations, and simulations results will be provided and discussed.

  16. Impact of imperfect information on network attack

    NASA Astrophysics Data System (ADS)

    Melchionna, Andrew; Caloca, Jesus; Squires, Shane; Antonsen, Thomas M.; Ott, Edward; Girvan, Michelle

    2015-03-01

    This paper explores the effectiveness of network attack when the attacker has imperfect information about the network. For Erdős-Rényi networks, we observe that dynamical importance and betweenness centrality-based attacks are surprisingly robust to the presence of a moderate amount of imperfect information and are more effective compared with simpler degree-based attacks even at moderate levels of network information error. In contrast, for scale-free networks the effectiveness of attack is much less degraded by a moderate level of information error. Furthermore, in the Erdős-Rényi case the effectiveness of network attack is much more degraded by missing links as compared with the same number of false links.

  17. Impact of imperfect information on network attack.

    PubMed

    Melchionna, Andrew; Caloca, Jesus; Squires, Shane; Antonsen, Thomas M; Ott, Edward; Girvan, Michelle

    2015-03-01

    This paper explores the effectiveness of network attack when the attacker has imperfect information about the network. For Erdős-Rényi networks, we observe that dynamical importance and betweenness centrality-based attacks are surprisingly robust to the presence of a moderate amount of imperfect information and are more effective compared with simpler degree-based attacks even at moderate levels of network information error. In contrast, for scale-free networks the effectiveness of attack is much less degraded by a moderate level of information error. Furthermore, in the Erdős-Rényi case the effectiveness of network attack is much more degraded by missing links as compared with the same number of false links. PMID:25871157

  18. Information Services in the International Network Marketplace.

    ERIC Educational Resources Information Center

    Hepworth, Mark E.

    1987-01-01

    Examines the internationalism of the network marketplace through case studies of the London Stock Exchange and I. P. Sharp Associates, a Canadian computer service bureau. Discussion focuses on the importance of transnational computer networks to the production of information services and marketplace expansion, and global information policy issues.…

  19. Informational Benefits via Knowledge Networks among Farmers

    ERIC Educational Resources Information Center

    Sligo, F. X.; Massey, Claire; Lewis, Kate

    2005-01-01

    Purpose: This research aimed to obtain insights into how farmers on small and medium-sized farms perceived the benefits of the information they receive from their interpersonal networks and other sources. Design/methodology/approach: Farmers' information environments were explored using socio-spatial knowledge networks, diaries and in-depth…

  20. High speed laser communication network for satellite systems

    NASA Astrophysics Data System (ADS)

    Panahi, Allen; Kazemi, Alex A.

    2011-06-01

    Using optical links in space and building high speed laser communications network has proven to be an extremely complicated task and many such schemes were tried without success in the past. However, in the last few years, there has been impressive progress made to bring the concept to fruition in civilian and government-non classified projects. In this paper we will focus on the requirements of the space-based lasers and optics used for beam forming, as well as receiver antenna gain and detectors used in free space communications. High data rate, small antenna size, narrow beam divergence, and a narrow field of view are characteristics of laser communications that offer a number of potential advantages for system design. Space-based optical communications using satellites in low earth orbit (LEO) and Geo-synchronous orbits (GEO) hold great promise for the proposed Internet in the Sky network of the future. Also discussed are the critical parameters in the transmitter, channel, receiver, and link budget that are employed in successful inter-satellite communications system. We cover that Laser Communications offer a viable alternative to established RF communications for inter-satellite links and other applications where high performance links are a necessity.

  1. Future large broadband switched satellite communications networks

    NASA Technical Reports Server (NTRS)

    Staelin, D. H.; Harvey, R. R.

    1979-01-01

    Critical technical, market, and policy issues relevant to future large broadband switched satellite networks are summarized. Our market projections for the period 1980 to 2000 are compared. Clusters of switched satellites, in lieu of large platforms, etc., are shown to have significant advantages. Analysis of an optimum terrestrial network architecture suggests the proper densities of ground stations and that link reliabilities 99.99% may entail less than a 10% cost premium for diversity protection at 20/30 GHz. These analyses suggest that system costs increase as the 0.6 power of traffic. Cost estimates for nominal 20/30 GHz satellite and ground facilities suggest optimum system configurations might employ satellites with 285 beams, multiple TDMA bands each carrying 256 Mbps, and 16 ft ground station antennas. A nominal development program is outlined.

  2. Enabling information management systems in tactical network environments

    NASA Astrophysics Data System (ADS)

    Carvalho, Marco; Uszok, Andrzej; Suri, Niranjan; Bradshaw, Jeffrey M.; Ceccio, Philip J.; Hanna, James P.; Sinclair, Asher

    2009-05-01

    Net-Centric Information Management (IM) and sharing in tactical environments promises to revolutionize forward command and control capabilities by providing ubiquitous shared situational awareness to the warfighter. This vision can be realized by leveraging the tactical and Mobile Ad hoc Networks (MANET) which provide the underlying communications infrastructure, but, significant technical challenges remain. Enabling information management in these highly dynamic environments will require multiple support services and protocols which are affected by, and highly dependent on, the underlying capabilities and dynamics of the tactical network infrastructure. In this paper we investigate, discuss, and evaluate the effects of realistic tactical and mobile communications network environments on mission-critical information management systems. We motivate our discussion by introducing the Advanced Information Management System (AIMS) which is targeted for deployment in tactical sensor systems. We present some operational requirements for AIMS and highlight how critical IM support services such as discovery, transport, federation, and Quality of Service (QoS) management are necessary to meet these requirements. Our goal is to provide a qualitative analysis of the impact of underlying assumptions of availability and performance of some of the critical services supporting tactical information management. We will also propose and describe a number of technologies and capabilities that have been developed to address these challenges, providing alternative approaches for transport, service discovery, and federation services for tactical networks.

  3. Information and Communication Technologies in Social Work

    PubMed Central

    Perron, Brian E.; Taylor, Harry O.; Glass, Joseph E.; Margerum-Leys, Jon

    2011-01-01

    Information and communication technologies (ICTs) are electronic tools used to convey, manipulate and store information. The exponential growth of Internet access and ICTs greatly influenced social, political, and economic processes in the United States, and worldwide. Regardless of the level of practice, ICTs will continue influencing the careers of social workers and the clients they serve. ICTs have received some attention in the social work literature and curriculum, but we argue that this level of attention is not adequate given their ubiquity, growth and influence, specifically as it relates to upholding social work ethics. Significant attention is needed to help ensure social workers are responsive to the technological changes in the health care system, including the health care infrastructure and use of technology among clients. Social workers also need ICT competencies in order to effectively lead different types of social change initiatives or collaborate with professionals of other disciplines who are using ICTs as part of existing strategies. This paper also identifies potential pitfalls and challenges with respect to the adoption of ICTs, with recommendations for advancing their use in practice, education, and research. PMID:21691444

  4. Information and Communication Technologies in Social Work.

    PubMed

    Perron, Brian E; Taylor, Harry O; Glass, Joseph E; Margerum-Leys, Jon

    2010-01-01

    Information and communication technologies (ICTs) are electronic tools used to convey, manipulate and store information. The exponential growth of Internet access and ICTs greatly influenced social, political, and economic processes in the United States, and worldwide. Regardless of the level of practice, ICTs will continue influencing the careers of social workers and the clients they serve. ICTs have received some attention in the social work literature and curriculum, but we argue that this level of attention is not adequate given their ubiquity, growth and influence, specifically as it relates to upholding social work ethics. Significant attention is needed to help ensure social workers are responsive to the technological changes in the health care system, including the health care infrastructure and use of technology among clients. Social workers also need ICT competencies in order to effectively lead different types of social change initiatives or collaborate with professionals of other disciplines who are using ICTs as part of existing strategies. This paper also identifies potential pitfalls and challenges with respect to the adoption of ICTs, with recommendations for advancing their use in practice, education, and research. PMID:21691444

  5. PREFACE: Quantum Information, Communication, Computation and Cryptography

    NASA Astrophysics Data System (ADS)

    Benatti, F.; Fannes, M.; Floreanini, R.; Petritis, D.

    2007-07-01

    The application of quantum mechanics to information related fields such as communication, computation and cryptography is a fast growing line of research that has been witnessing an outburst of theoretical and experimental results, with possible practical applications. On the one hand, quantum cryptography with its impact on secrecy of transmission is having its first important actual implementations; on the other hand, the recent advances in quantum optics, ion trapping, BEC manipulation, spin and quantum dot technologies allow us to put to direct test a great deal of theoretical ideas and results. These achievements have stimulated a reborn interest in various aspects of quantum mechanics, creating a unique interplay between physics, both theoretical and experimental, mathematics, information theory and computer science. In view of all these developments, it appeared timely to organize a meeting where graduate students and young researchers could be exposed to the fundamentals of the theory, while senior experts could exchange their latest results. The activity was structured as a school followed by a workshop, and took place at The Abdus Salam International Center for Theoretical Physics (ICTP) and The International School for Advanced Studies (SISSA) in Trieste, Italy, from 12-23 June 2006. The meeting was part of the activity of the Joint European Master Curriculum Development Programme in Quantum Information, Communication, Cryptography and Computation, involving the Universities of Cergy-Pontoise (France), Chania (Greece), Leuven (Belgium), Rennes1 (France) and Trieste (Italy). This special issue of Journal of Physics A: Mathematical and Theoretical collects 22 contributions from well known experts who took part in the workshop. They summarize the present day status of the research in the manifold aspects of quantum information. The issue is opened by two review articles, the first by G Adesso and F Illuminati discussing entanglement in continuous variable

  6. Ethics of Clear Health Communication: applying the CLean Look approach to Communicate Biobanking Information for Cancer research

    PubMed Central

    Koskan, Alexis; Arevalo, Mariana; Gwede, Clement K.; Quinn, Gwendolyn P.; Noel-Thomas, Shalewa A.; Luque, John S.; Wells, Kristen J.; Meade, Cathy D.

    2013-01-01

    Cancer innovations, such as biobanking technologies, are continuously evolving to improve our understanding and knowledge about cancer prevention and treatment modalities. However, the public receives little communication about biobanking and is often unaware about this innovation until asked to donate biospecimens. It is the researchers’ ethical duty to provide clear communications about biobanking and biospecimen research. Such information allows the public to understand biobanking processes and facilitates informed decision making about biospecimen donation. The aims of this paper are 1) to examine the importance of clear communication as an ethical imperative when conveying information about cancer innovations and 2) to illustrate the use of an organizing framework, the CLEAN (Culture, Literacy, Education, Assessment, and Networking) Look approach for creating educational priming materials about the topic of biobanking. PMID:23124500

  7. Mothers' use of information and communication technologies for information seeking.

    PubMed

    Jang, Juyoung; Dworkin, Jodi; Hessel, Heather

    2015-04-01

    Previous studies have revealed that information and communication technologies (ICTs) play a crucial role in parenting. Utilizing a national sample of mothers, the current study addresses mothers' information-seeking behaviors using ICTs utilizing the sense-making theoretical approach. Specifically, the study explored mothers' gap-bridging activities via online information venues including blogs, discussion boards/chatrooms, e-mailed newsletters, and online courses. Further, the associations were examined between mothers' demographic characteristics and their patterns of gap-bridging activities using online information venues. Latent class analysis revealed five latent classes: limited gap bridging, active gap bridging, problem identifiers, perspective explorers, and reassurance seekers. The "limited gap bridging" latent class was the most common class across online information venues. The other latent classes illustrate a more complex picture of mothers' gap-bridging activities depending on their needs. Mothers' demographic characteristics were associated with their patterns of gap-bridging activities. Implications of these findings for future research are discussed. PMID:25803204

  8. 10 CFR 75.12 - Communication of information to IAEA.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Communication of information to IAEA. 75.12 Section 75.12... AGREEMENT Facility and Location Information § 75.12 Communication of information to IAEA. (a) Except as... retained for 3 years after each change is made. (2) In considering such a request, it is the policy of...

  9. Communicating Cancer Risk Information: The Challenges of Uncertainty.

    ERIC Educational Resources Information Center

    Bottorff, Joan L.; Ratner, Pamela A.; Johnson, Joy L.; Lovato, Chris Y.; Joab, S. Amanda

    1998-01-01

    Accurate and sensitive communication of cancer-risk information is important. Based on a literature review of 75 research reports, expert opinion papers, and clinical protocols, a synthesis of what is known about the communication of cancer-risk information is presented. Relevance of information to those not tested is discussed. (Author/EMK)

  10. [Research on Zhejiang blood information network and management system].

    PubMed

    Yan, Li-Xing; Xu, Yan; Meng, Zhong-Hua; Kong, Chang-Hong; Wang, Jian-Min; Jin, Zhen-Liang; Wu, Shi-Ding; Chen, Chang-Shui; Luo, Ling-Fei

    2007-02-01

    This research was aimed to develop the first level blood information centralized database and real time communication network at a province area in China. Multiple technology like local area network database separate operation, real time data concentration and distribution mechanism, allopatric backup, and optical fiber virtual private network (VPN) were used. As a result, the blood information centralized database and management system were successfully constructed, which covers all the Zhejiang province, and the real time exchange of blood data was realised. In conclusion, its implementation promote volunteer blood donation and ensure the blood safety in Zhejiang, especially strengthen the quick response to public health emergency. This project lays the first stone of centralized test and allotment among blood banks in Zhejiang, and can serve as a reference of contemporary blood bank information systems in China. PMID:17490550

  11. Applying Model Based Systems Engineering to NASA's Space Communications Networks

    NASA Technical Reports Server (NTRS)

    Bhasin, Kul; Barnes, Patrick; Reinert, Jessica; Golden, Bert

    2013-01-01

    System engineering practices for complex systems and networks now require that requirement, architecture, and concept of operations product development teams, simultaneously harmonize their activities to provide timely, useful and cost-effective products. When dealing with complex systems of systems, traditional systems engineering methodology quickly falls short of achieving project objectives. This approach is encumbered by the use of a number of disparate hardware and software tools, spreadsheets and documents to grasp the concept of the network design and operation. In case of NASA's space communication networks, since the networks are geographically distributed, and so are its subject matter experts, the team is challenged to create a common language and tools to produce its products. Using Model Based Systems Engineering methods and tools allows for a unified representation of the system in a model that enables a highly related level of detail. To date, Program System Engineering (PSE) team has been able to model each network from their top-level operational activities and system functions down to the atomic level through relational modeling decomposition. These models allow for a better understanding of the relationships between NASA's stakeholders, internal organizations, and impacts to all related entities due to integration and sustainment of existing systems. Understanding the existing systems is essential to accurate and detailed study of integration options being considered. In this paper, we identify the challenges the PSE team faced in its quest to unify complex legacy space communications networks and their operational processes. We describe the initial approaches undertaken and the evolution toward model based system engineering applied to produce Space Communication and Navigation (SCaN) PSE products. We will demonstrate the practice of Model Based System Engineering applied to integrating space communication networks and the summary of its

  12. Optimal multicast communication in wormhole-routed torus networks

    SciTech Connect

    Robinson, D.F.; McKinley, P.K.; Cheng, B.H.C.

    1994-12-31

    This paper presents efficient algorithms that implement one-to-many, or multicast, communication in wormhole-routed torus networks. By exploiting the properties of the switching technology and the use of virtual channels, a minimum-time multicast algorithm is presented for n-dimensional torus networks that use deterministic, dimension-ordered routing of unicast messages. The algorithm can deliver a multicast message to m-1 destinations in [log{sub 2}m] message-passing steps, while avoiding contention among the constituent unicast messages. Performance results of a simulation study on torus networks are also given.

  13. Information theory perspective on network robustness

    NASA Astrophysics Data System (ADS)

    Schieber, Tiago A.; Carpi, Laura; Frery, Alejandro C.; Rosso, Osvaldo A.; Pardalos, Panos M.; Ravetti, Martín G.

    2016-01-01

    A crucial challenge in network theory is the study of the robustness of a network when facing a sequence of failures. In this work, we propose a dynamical definition of network robustness based on Information Theory, that considers measurements of the structural changes caused by failures of the network's components. Failures are defined here as a temporal process defined in a sequence. Robustness is then evaluated by measuring dissimilarities between topologies after each time step of the sequence, providing a dynamical information about the topological damage. We thoroughly analyze the efficiency of the method in capturing small perturbations by considering different probability distributions on networks. In particular, we find that distributions based on distances are more consistent in capturing network structural deviations, as better reflect the consequences of the failures. Theoretical examples and real networks are used to study the performance of this methodology.

  14. Noise enhances information transfer in hierarchical networks.

    PubMed

    Czaplicka, Agnieszka; Holyst, Janusz A; Sloot, Peter M A

    2013-01-01

    We study the influence of noise on information transmission in the form of packages shipped between nodes of hierarchical networks. Numerical simulations are performed for artificial tree networks, scale-free Ravasz-Barabási networks as well for a real network formed by email addresses of former Enron employees. Two types of noise are considered. One is related to packet dynamics and is responsible for a random part of packets paths. The second one originates from random changes in initial network topology. We find that the information transfer can be enhanced by the noise. The system possesses optimal performance when both kinds of noise are tuned to specific values, this corresponds to the Stochastic Resonance phenomenon. There is a non-trivial synergy present for both noisy components. We found also that hierarchical networks built of nodes of various degrees are more efficient in information transfer than trees with a fixed branching factor. PMID:23390574

  15. Noise enhances information transfer in hierarchical networks

    PubMed Central

    Czaplicka, Agnieszka; Holyst, Janusz A.; Sloot, Peter M. A.

    2013-01-01

    We study the influence of noise on information transmission in the form of packages shipped between nodes of hierarchical networks. Numerical simulations are performed for artificial tree networks, scale-free Ravasz-Barabási networks as well for a real network formed by email addresses of former Enron employees. Two types of noise are considered. One is related to packet dynamics and is responsible for a random part of packets paths. The second one originates from random changes in initial network topology. We find that the information transfer can be enhanced by the noise. The system possesses optimal performance when both kinds of noise are tuned to specific values, this corresponds to the Stochastic Resonance phenomenon. There is a non-trivial synergy present for both noisy components. We found also that hierarchical networks built of nodes of various degrees are more efficient in information transfer than trees with a fixed branching factor. PMID:23390574

  16. Role of Communication Networks in Behavioral Systems Analysis

    ERIC Educational Resources Information Center

    Houmanfar, Ramona; Rodrigues, Nischal Joseph; Smith, Gregory S.

    2009-01-01

    This article provides an overview of communication networks and the role of verbal behavior in behavioral systems analysis. Our discussion highlights styles of leadership in the design and implementation of effective organizational contingencies that affect ways by which coordinated work practices are managed. We draw upon literature pertaining to…

  17. Communication Resource Use in a Networked Collaborative Design Environment.

    ERIC Educational Resources Information Center

    Gay, Geri; Lentini, Marc

    The purpose of this exploratory study was to examine student use of a prototype networked collaborative design environment to support or augment learning about engineering design. The theoretical framework is based primarily on Vygotsky's social construction of knowledge and the belief that collaboration and communication are critical components…

  18. Indian-Spanish Communication Networks: Continuity in the Greater Southwest.

    ERIC Educational Resources Information Center

    Riley, Carroll L.; Manson, Joni L.

    Trade and communication networks established by Indian groups in the 15th century A.D. linked the Southwest to Mesoamerica, the Plains and the Pacific littoral; these routes were later used by the Spanish and Americans, and today major highways follow ancient Indian routes. The main east-west route had major termini at Cibola (near Zuni) in the…

  19. Considerations on communications network protocols in deep space

    NASA Technical Reports Server (NTRS)

    Clare, L. P.; Agre, J. R.; Yan, T.

    2001-01-01

    Communications supporting deep space missions impose numerous unique constraints that impact the architectural choices made for cost-effectiveness. We are entering the era where networks that exist in deep space are needed to support planetary exploration. Cost-effective performance will require a balanced integration of applicable widely used standard protocols with new and innovative designs.

  20. Results of computer network experiment via the Japanese communication satellite CS - Performance evaluation of communication protocols

    NASA Astrophysics Data System (ADS)

    Ito, A.; Kakinuma, Y.; Uchida, K.; Matsumoto, K.; Takahashi, H.

    1984-03-01

    Computer network experiments have been performed by using the Japanese communication satellite CS. The network is of a centralized (star) type, consisting of one center station and many user stations. The protocols are determined taking into consideration the long round trip delay of a satellite channel. This paper treats the communication protocol aspects of the experiments. Performances of the burst level and the link protocols (which correspond nearly to data link layer of OSI 7 layer model) are evaluated. System performances of throughput, delay, link level overhead are measured by using the statistically generated traffic.

  1. Role of Communications Satellites in the National and Global Information Infrastructure

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Early in 1995, the Satellite Industry Task Force (SITF) was initiated by executives of the satellite industry to define the role for communication satellites in the National and Global Information Infrastructure (NII/GII). Satellites are essential to this information network because they offer ubiquitous coverage and less time to market. SITF, which was chaired by Dr. Thomas Brackey of the Hughes Space and Communication Division, grew out of a series of workshops held during the summer of 1994 by the communication industry, NASA, and the Defense Information Systems Agency (DISA). Experts were convened from 20 companies representing satellite and terrestrial network builders, operators, and users. For 8 months they worked to identify challenges for the satellite industry to play a pivotal role in the National and Global Information Infrastructure. NASA Lewis Research Center personnel helped out with technical and policy matters.

  2. Future DCS objectives in communication network timing and synchronization

    NASA Technical Reports Server (NTRS)

    Mensch, J. R.

    1973-01-01

    The Defense Communication System will be moving rapidly toward providing switched digital service to it's users within the next ten years. The principal driving force in the transition to a digital system is the requirement for high performance secure voice service. Additionally, the anticipated data requirements in this time frame can be handled most effectively by a digital network. The characteristics of a switched digital network which impose timing and synchronization requirements on the system design are presented. Several alternative approaches to implementing a timing subsystem suitable for a switched digital communications system have been considered. These include pulse stuffing, independent stable clocks, and clock correction techniques. The advantages and disadvantages of each approach are discussed relative to both the strategic and tactical communication system requirements.

  3. 47 CFR 64.2009 - Safeguards required for use of customer proprietary network information.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Safeguards required for use of customer proprietary network information. 64.2009 Section 64.2009 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2009 Safeguards required for use of customer proprietary...

  4. 47 CFR 64.2010 - Safeguards on the disclosure of customer proprietary network information.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 3 2011-10-01 2011-10-01 false Safeguards on the disclosure of customer proprietary network information. 64.2010 Section 64.2010 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2010 Safeguards on the disclosure of customer proprietary...

  5. 47 CFR 51.335 - Notice of network changes: Confidential or proprietary information.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 3 2011-10-01 2011-10-01 false Notice of network changes: Confidential or proprietary information. 51.335 Section 51.335 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED... Carriers § 51.335 Notice of network changes: Confidential or proprietary information. (a) If an...

  6. 47 CFR 64.2009 - Safeguards required for use of customer proprietary network information.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 3 2011-10-01 2011-10-01 false Safeguards required for use of customer proprietary network information. 64.2009 Section 64.2009 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2009 Safeguards required for use of customer proprietary...

  7. 47 CFR 64.2007 - Approval required for use of customer proprietary network information.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 3 2011-10-01 2011-10-01 false Approval required for use of customer proprietary network information. 64.2007 Section 64.2007 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2007 Approval required for use of customer proprietary...

  8. 47 CFR 64.2007 - Approval required for use of customer proprietary network information.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Approval required for use of customer proprietary network information. 64.2007 Section 64.2007 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2007 Approval required for use of customer proprietary...

  9. 47 CFR 51.335 - Notice of network changes: Confidential or proprietary information.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Notice of network changes: Confidential or proprietary information. 51.335 Section 51.335 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED... Carriers § 51.335 Notice of network changes: Confidential or proprietary information. (a) If an...

  10. 47 CFR 64.2010 - Safeguards on the disclosure of customer proprietary network information.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Safeguards on the disclosure of customer proprietary network information. 64.2010 Section 64.2010 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2010 Safeguards on the disclosure of customer proprietary...

  11. 47 CFR 64.2007 - Approval required for use of customer proprietary network information.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 3 2012-10-01 2012-10-01 false Approval required for use of customer proprietary network information. 64.2007 Section 64.2007 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2007 Approval required for use of customer proprietary...

  12. 47 CFR 64.2007 - Approval required for use of customer proprietary network information.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 3 2014-10-01 2014-10-01 false Approval required for use of customer proprietary network information. 64.2007 Section 64.2007 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2007 Approval required for use of customer proprietary...

  13. 47 CFR 51.335 - Notice of network changes: Confidential or proprietary information.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 3 2014-10-01 2014-10-01 false Notice of network changes: Confidential or proprietary information. 51.335 Section 51.335 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED... Carriers § 51.335 Notice of network changes: Confidential or proprietary information. (a) If an...

  14. 47 CFR 64.2009 - Safeguards required for use of customer proprietary network information.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 3 2012-10-01 2012-10-01 false Safeguards required for use of customer proprietary network information. 64.2009 Section 64.2009 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2009 Safeguards required for use of customer proprietary...

  15. 47 CFR 51.335 - Notice of network changes: Confidential or proprietary information.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 3 2012-10-01 2012-10-01 false Notice of network changes: Confidential or proprietary information. 51.335 Section 51.335 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED... Carriers § 51.335 Notice of network changes: Confidential or proprietary information. (a) If an...

  16. 47 CFR 51.335 - Notice of network changes: Confidential or proprietary information.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 3 2013-10-01 2013-10-01 false Notice of network changes: Confidential or proprietary information. 51.335 Section 51.335 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED... Carriers § 51.335 Notice of network changes: Confidential or proprietary information. (a) If an...

  17. 47 CFR 64.2009 - Safeguards required for use of customer proprietary network information.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 3 2013-10-01 2013-10-01 false Safeguards required for use of customer proprietary network information. 64.2009 Section 64.2009 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2009 Safeguards required for use of customer proprietary...

  18. 47 CFR 64.2007 - Approval required for use of customer proprietary network information.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 3 2013-10-01 2013-10-01 false Approval required for use of customer proprietary network information. 64.2007 Section 64.2007 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2007 Approval required for use of customer proprietary...

  19. 47 CFR 64.2009 - Safeguards required for use of customer proprietary network information.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 3 2014-10-01 2014-10-01 false Safeguards required for use of customer proprietary network information. 64.2009 Section 64.2009 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2009 Safeguards required for use of customer proprietary...

  20. 47 CFR 64.2010 - Safeguards on the disclosure of customer proprietary network information.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 3 2014-10-01 2014-10-01 false Safeguards on the disclosure of customer proprietary network information. 64.2010 Section 64.2010 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) MISCELLANEOUS RULES RELATING TO COMMON CARRIERS Customer Proprietary Network Information §...

  1. 47 CFR 64.2010 - Safeguards on the disclosure of customer proprietary network information.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 3 2012-10-01 2012-10-01 false Safeguards on the disclosure of customer proprietary network information. 64.2010 Section 64.2010 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2010 Safeguards on the disclosure of customer proprietary...

  2. 47 CFR 64.2010 - Safeguards on the disclosure of customer proprietary network information.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 3 2013-10-01 2013-10-01 false Safeguards on the disclosure of customer proprietary network information. 64.2010 Section 64.2010 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... Proprietary Network Information § 64.2010 Safeguards on the disclosure of customer proprietary...

  3. Informal and Formal Approaches to Communicative Language Teaching.

    ERIC Educational Resources Information Center

    Ellis, Rod

    1982-01-01

    Discusses the use of the term "communicative" in describing approaches to foreign- or second-language teaching. Suggests that a distinction should be drawn between informal communicative approaches which promote second-language acquisition and formal communicative approaches which promote conscious learning. Examines conditions for achieving both…

  4. The 30/20 GHz communications satellite trunking network study

    NASA Technical Reports Server (NTRS)

    Kolb, W.

    1981-01-01

    Alternative transmission media for a CONUS-wide trunking network in the years 1990 and 2000 are examined. The alternative technologies comprised fiber optic cable, conventional C- and Ku-band satellites, and 30/20 GHz satellites. Three levels of implementation were considered - a 10-city network, a 20-city network, and a 40-city network. The cities selected were the major metropolitan areas with the greatest communications demand. All intercity voice, data, and video traffic carried more than 40 miles was included in the analysis. In the optimized network, traffic transmitted less than 500 miles was found to be better served by fiber optic cable in 1990. By the year 2000, the crossover point would be down to 200 miles, assuming availability of 30/20 GHz satellites.

  5. Constructing Overlay Networks with Short Paths and Low Communication Cost

    NASA Astrophysics Data System (ADS)

    Makikawa, Fuminori; Tsuchiya, Tatsuhiro; Kikuno, Tohru

    A Peer-To-Peer (P2P) application uses an overlay network which is a virtual network constructed over the physical network. Traditional overlay construction methods do not take physical location of nodes into consideration, resulting in a large amount of redundant traffic. Some proximity-aware construction methods have been proposed to address this problem. These methods typically connect nearby nodes in the physical network. However, as the number of nodes increases, the path length of a route between two distant nodes rapidly increases. To alleviate this problem, we propose a technique which can be incorporated in existing overlay construction methods. The idea behind this technique is to employ long links to directly connect distant nodes. Through simulation experiments, we show that using our proposed technique, networks can achieve small path length and low communication cost while maintaining high resiliency to failures.

  6. Satellite communications for the next generation telecommunication services and networks

    NASA Technical Reports Server (NTRS)

    Chitre, D. M.

    1991-01-01

    Satellite communications can play an important role in provisioning the next-generation telecommunication services and networks, provided the protocols specifying these services and networks are satellite-compatible and the satellite subnetworks, consisting of earth stations interconnected by the processor and the switch on board the satellite, interwork effectively with the terrestrial networks. The specific parameters and procedures of frame relay and broadband integrated services digital network (B-ISDN) protocols which are impacted by a satellite delay. Congestion and resource management functions for frame relay and B-ISDN are discussed in detail, describing the division of these functions between earth stations and on board the satellite. Specific onboard and ground functions are identified as potential candidates for their implementation via neural network technology.

  7. Test experience on an ultrareliable computer communication network

    NASA Technical Reports Server (NTRS)

    Abbott, L. W.

    1984-01-01

    The dispersed sensor processing mesh (DSPM) is an experimental, ultrareliable, fault-tolerant computer communications network that exhibits an organic-like ability to regenerate itself after suffering damage. The regeneration is accomplished by two routines - grow and repair. This paper discusses the DSPM concept for achieving fault tolerance and provides a brief description of the mechanization of both the experiment and the six-node experimental network. The main topic of this paper is the system performance of the growth algorithm contained in the grow routine. The characteristics imbued to DSPM by the growth algorithm are also discussed. Data from an experimental DSPM network and software simulation of larger DSPM-type networks are used to examine the inherent limitation on growth time by the growth algorithm and the relationship of growth time to network size and topology.

  8. Test experience on an ultrareliable computer communication network

    NASA Technical Reports Server (NTRS)

    Abbott, L. W.

    1984-01-01

    The dispersed sensor processing mesh (DSPM) is an experimental, ultra-reliable, fault-tolerant computer communications network that exhibits an organic-like ability to regenerate itself after suffering damage. The regeneration is accomplished by two routines - grow and repair. This paper discusses the DSPM concept for achieving fault tolerance and provides a brief description of the mechanization of both the experiment and the six-node experimental network. The main topic of this paper is the system performance of the growth algorithm contained in the grow routine. The characteristics imbued to DSPM by the growth algorithm are also discussed. Data from an experimental DSPM network and software simulation of larger DSPM-type networks are used to examine the inherent limitation on growth time by the growth algorithm and the relationship of growth time to network size and topology.

  9. Tufts academic health information network: concept and scenario.

    PubMed

    Stearns, N S

    1986-04-01

    Tufts University School of Medicine's new health sciences education building, the Arthur M. Sackler Center for Health Communications, will house a modern medical library and computer center, classrooms, auditoria, and media facilities. The building will also serve as the center for an information and communication network linking the medical school and adjacent New England Medical Center, Tufts' primary teaching hospital, with Tufts Associated Teaching Hospitals throughout New England. Ultimately, the Tufts network will join other gateway networks, information resource facilities, health care institutions, and medical schools throughout the world. The center and the network are intended to facilitate and improve the education of health professionals, the delivery of health care to patients, the conduct of research, and the implementation of administrative management approaches that should provide more efficient utilization of resources and save dollars. A model and scenario show how health care delivery and health care education are integrated through better use of information transfer technologies by health information specialists, practitioners, and educators. PMID:3708191

  10. The Study on the Communication Network of Wide Area Measurement System in Electricity Grid

    NASA Astrophysics Data System (ADS)

    Xiaorong, Cheng; Ying, Wang; Yangdan, Ni

    Wide area measurement system(WAMS) is a fundamental part of security defense in Smart Grid, and the communication system of WAMS is an important part of Electric power communication network. For a large regional network is concerned, the real-time data which is transferred in the communication network of WAMS will affect the safe operation of the power grid directly. Therefore, WAMS raised higher requirements for real-time, reliability and security to its communication network. In this paper, the architecture of WASM communication network was studied according to the seven layers model of the open systems interconnection(OSI), and the network architecture was researched from all levels. We explored the media of WAMS communication network, the network communication protocol and network technology. Finally, the delay of the network were analyzed.

  11. Communications performance of an undersea acoustic large-area network

    NASA Astrophysics Data System (ADS)

    Kriewaldt, Hannah A.; Rice, Joseph A.

    2005-04-01

    The U.S. Navy is developing Seaweb acoustic networking capability for integrating undersea systems. Seaweb architectures generally involve a wide-area network of fixed nodes consistent with future distributed autonomous sensors on the seafloor. Mobile nodes including autonomous undersea vehicles (AUVs) and submarines operate in the context of the grid by using the fixed nodes as both navigation reference points and communication access points. In October and November 2004, Theater Anti-Submarine Warfare Exercise (TASWEX04) showcased Seaweb in its first fleet appearance. This paper evaluates the TASWEX04 Seaweb performance in support of networked communications between a submarine and a surface ship. Considerations include physical-layer dependencies on the 9-14 kHz acoustic channel, such as refraction, wind-induced ambient noise, and submarine aspect angle. [Work supported by SSC San Diego.

  12. NASA Near Earth Network (NEN), Deep Space Network (DSN) and Space Network (SN) Support of CubeSat Communications

    NASA Technical Reports Server (NTRS)

    Schaire, Scott H.; Altunc, Serhat; Bussey, George; Shaw, Harry; Horne, Bill; Schier, Jim

    2015-01-01

    There has been a historical trend to increase capability and drive down the Size, Weight and Power (SWAP) of satellites and that trend continues today. Small satellites, including systems conforming to the CubeSat specification, because of their low launch and development costs, are enabling new concepts and capabilities for science investigations across multiple fields of interest to NASA. NASA scientists and engineers across many of NASAs Mission Directorates and Centers are developing exciting CubeSat concepts and welcome potential partnerships for CubeSat endeavors. From a communications and tracking point of view, small satellites including CubeSats are a challenge to coordinate because of existing small spacecraft constraints, such as limited SWAP and attitude control, low power, and the potential for high numbers of operational spacecraft. The NASA Space Communications and Navigation (SCaN) Programs Near Earth Network (NEN), Deep Space Network (DSN) and the Space Network (SN) are customer driven organizations that provide comprehensive communications services for space assets including data transport between a missions orbiting satellite and its Mission Operations Center (MOC). The NASA NEN consists of multiple ground antennas. The SN consists of a constellation of geosynchronous (Earth orbiting) relay satellites, named the Tracking and Data Relay Satellite System (TDRSS). The DSN currently makes available 13 antennas at its three tracking stations located around the world for interplanetary communication. The presentation will analyze how well these space communication networks are positioned to support the emerging small satellite and CubeSat market. Recognizing the potential support, the presentation will review the basic capabilities of the NEN, DSN and SN in the context of small satellites and will present information about NEN, DSN and SN-compatible flight radios and antenna development activities at the Goddard Space Flight Center (GSFC) and across

  13. Progress on the Development of Future Airport Surface Wireless Communications Network

    NASA Technical Reports Server (NTRS)

    Kerczewski, Robert J.; Budinger, James M.; Brooks, David E.; Franklin, Morgan; DeHart, Steve; Dimond, Robert P.; Borden, Michael

    2009-01-01

    Continuing advances in airport surface management and improvements in airport surface safety are required to enable future growth in air traffic throughout the airspace, as airport arrival and departure delays create a major system bottleneck. These airport management and safety advances will be built upon improved communications, navigation, surveillance, and weather sensing, creating an information environment supporting system automation. The efficient movement of the digital data generated from these systems requires an underlying communications network infrastructure to connect data sources with the intended users with the required quality of service. Current airport surface communications consists primarily of buried copper or fiber cable. Safety related communications with mobile airport surface assets occurs over 25 kHz VHF voice and data channels. The available VHF spectrum, already congested in many areas, will be insufficient to support future data traffic requirements. Therefore, a broadband wireless airport surface communications network is considered a requirement for the future airport component of the air transportation system. Progress has been made on defining the technology and frequency spectrum for the airport surface wireless communications network. The development of a test and demonstration facility and the definition of required testing and standards development are now underway. This paper will review the progress and planned future work.

  14. Teaching Networking: An Interpersonal Communication Competence Perspective

    ERIC Educational Resources Information Center

    Kokkonen, Lotta; Almonkari, Merja

    2015-01-01

    Modern working life calls for competences that enable people to be creative, innovative and effective. Studies looking at contemporary enterprises and organisations such as businesses and schools have shown that many of the qualifications that graduating students would need, including informal learning (see Gielen, Hoeve & Nieuwenhuis 2003),…

  15. Communications, Navigation, and Network Reconfigurable Test-bed Flight Hardware Compatibility Test S

    NASA Technical Reports Server (NTRS)

    2010-01-01

    Communications, Navigation, and Network Reconfigurable Test-bed Flight Hardware Compatibility Test Sets and Networks Integration Management Office Testing for the Tracking and Data Relay Satellite System

  16. Operational Concepts for a Generic Space Exploration Communication Network Architecture

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.; Vaden, Karl R.; Jones, Robert E.; Roberts, Anthony M.

    2015-01-01

    This document is one of three. It describes the Operational Concept (OpsCon) for a generic space exploration communication architecture. The purpose of this particular document is to identify communication flows and data types. Two other documents accompany this document, a security policy profile and a communication architecture document. The operational concepts should be read first followed by the security policy profile and then the architecture document. The overall goal is to design a generic space exploration communication network architecture that is affordable, deployable, maintainable, securable, evolvable, reliable, and adaptable. The architecture should also require limited reconfiguration throughout system development and deployment. System deployment includes: subsystem development in a factory setting, system integration in a laboratory setting, launch preparation, launch, and deployment and operation in space.

  17. Partial synchronization in stochastic dynamical networks with switching communication channels

    NASA Astrophysics Data System (ADS)

    Huang, Chi; Ho, Daniel W. C.; Lu, Jianquan; Kurths, Jürgen

    2012-06-01

    In this paper, the partial synchronization problem of stochastic dynamical networks (SDNs) is investigated. Unlike the existing models, the SDN considered in this paper suffers from a class of communication constraint—only part of nodes' states can be transmitted. Thus, less nodes' states can be used to synchronize the SDN, which makes the analysis of the synchronization problem much harder. A set of channel matrices are introduced to reflect such kind of constraint. Furthermore, due to unpredictable environmental changes, the channel matrices can switch among some communication modes. The switching considered here is governed by a Markov process. To overcome the difficulty, a regrouping method is employed to derive our main results. The obtained conditions guarantee that partial synchronization can be achieved for SDNs under switching communication constraint. Finally, numerical examples are given to illustrate the effectiveness of the theoretical results and how the communication constraint influences synchronization result.

  18. The Deep Space Network information system in the year 2000

    NASA Technical Reports Server (NTRS)

    Markley, R. W.; Beswick, C. A.

    1992-01-01

    The Deep Space Network (DSN), the largest, most sensitive scientific communications and radio navigation network in the world, is considered. Focus is made on the telemetry processing, monitor and control, and ground data transport architectures of the DSN ground information system envisioned for the year 2000. The telemetry architecture will be unified from the front-end area to the end user. It will provide highly automated monitor and control of the DSN, automated configuration of support activities, and a vastly improved human interface. Automated decision support systems will be in place for DSN resource management, performance analysis, fault diagnosis, and contingency management.

  19. Hierarchical social networks and information flow

    NASA Astrophysics Data System (ADS)

    López, Luis; F. F. Mendes, Jose; Sanjuán, Miguel A. F.

    2002-12-01

    Using a simple model for the information flow on social networks, we show that the traditional hierarchical topologies frequently used by companies and organizations, are poorly designed in terms of efficiency. Moreover, we prove that this type of structures are the result of the individual aim of monopolizing as much information as possible within the network. As the information is an appropriate measurement of centrality, we conclude that this kind of topology is so attractive for leaders, because the global influence each actor has within the network is completely determined by the hierarchical level occupied.

  20. Protocol for a Delay-Tolerant Data-Communication Network

    NASA Technical Reports Server (NTRS)

    Torgerson, Jordan; Hooke, Adrian; Burleigh, Scott; Fall, Kevin

    2004-01-01

    As its name partly indicates, the Delay-Tolerant Networking (DTN) Bundle Protocol is a protocol for delay-tolerant transmission of data via communication networks. This protocol was conceived as a result of studies of how to adapt Internet protocols so that Internet-like services could be provided across interplanetary distances in support of deep-space exploration. The protocol, and software to implement the protocol, is being developed in collaboration among experts at NASA's Jet Propulsion Laboratory and other institutions. No current Internet protocols can accommodate long transmission delay times or intermittent link connectivity. The DTN Bundle Protocol represents a departure from the standard Internet assumption that a continuous path is available from a host computer to a client computer: It provides for routing of data through networks that may be disjointed and may be characterized by long transmission delays. In addition to networks that include deepspace communication links, examples of such networks include terrestrial ones within which branches are temporarily disconnected. The protocol is based partly on the definition of a message-based overlay above the transport layers of the networks on which it is hosted.

  1. Leveraging Information Technology. Track V: Communications.

    ERIC Educational Resources Information Center

    CAUSE, Boulder, CO.

    Seven papers from the 1987 CAUSE conference's Track V, Communications, are presented. They include: "University of Miami LAN: A Case Study" (Ruben Lopez and M. Lewis Temares); "Designing and Implementing an Integrated Communications Environment in a Small College" (Charles S. Garratt IV, Jack M. Lewis, and John L. Van Hemert); "Commonwealth of…

  2. Communication Channels and Information Flow among Ethnics.

    ERIC Educational Resources Information Center

    Jeffres, Leo W.; Hur, K. Kyoon

    The questionnaire responses of 768 people from a variety of ethnic groups were analyzed to determine what communication channels were used to link ethnics to their native countries and to provide news of the ethnic community. The relationships between channel preferences and demographics, ethnicity, and communication channel patterns were also…

  3. 76 FR 36154 - In the Matter of Certain Equipment for Communications Networks, Including Switches, Routers...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-21

    ... COMMISSION In the Matter of Certain Equipment for Communications Networks, Including Switches, Routers... United States after importation of certain equipment for communications networks, including switches... importation, or the sale within the United States after importation of certain equipment for...

  4. Information Spread of Emergency Events: Path Searching on Social Networks

    PubMed Central

    Hu, Hongzhi; Wu, Tunan

    2014-01-01

    Emergency has attracted global attentions of government and the public, and it will easily trigger a series of serious social problems if it is not supervised effectively in the dissemination process. In the Internet world, people communicate with each other and form various virtual communities based on social networks, which lead to a complex and fast information spread pattern of emergency events. This paper collects Internet data based on data acquisition and topic detection technology, analyzes the process of information spread on social networks, describes the diffusions and impacts of that information from the perspective of random graph, and finally seeks the key paths through an improved IBF algorithm. Application cases have shown that this algorithm can search the shortest spread paths efficiently, which may help us to guide and control the information dissemination of emergency events on early warning. PMID:24600323

  5. Networked sensors for the future force (NSFF) advanced technology demonstration (ATD) communications systems

    NASA Astrophysics Data System (ADS)

    Nemeroff, Jay; DiPierro, Stefano

    2005-05-01

    The U.S. Army"s Future Combat Systems (FCS) and Future Force Warrior (FFW) will rely on the use of unattended, tactical sensors to detect and identify enemy targets in order to avoid enemy fires and enable precise networked fire to survive on the future battlefield with less armor protection. Successful implementation of these critical sensor fields requires the development of a specialized communications network infrastructure needed to disseminate sensor data to provide relevant, timely and accurate situational awareness information to the tactical common operating picture. The sensor network communications must support both static deployed and mobile ground and air robotic sensor arrays with robust, secure, stealthy, and jam resistant links. It is envisioned that tactical sensor networks can be deployed in a two tiered communications architecture that includes a lower sensor sub-layer consisting of acoustic, magnetic, Chemical/Biological and seismic detectors and an upper sub-layer consisting of infrared or visual imaging cameras. The upper sub-layer can be cued by the lower sub-layer and provides a seamless gateway link to higher echelon backbone tactical networks. The NSFF Advanced Technology Demonstration (ATD) communications effort focuses on providing Future Force systems such as the FCS and the Future Force Warrior with critical situational awareness data needed for survivability. The communications systems supporting this functionality must be designed such that unattended ground sensor data can flow seamlessly from the lowest unattended tactical sensor echelons into the Army"s tactical backbone networks while also allowing the "fusing" of the data with other intelligence information for correlation within a tactical command and control node. NSFF is realizing this capability by using advanced communications technologies developed under the Soldier Level Integrated Communications Environment (SLICE) Soldier Radio Waveform (SRW) project. These technologies

  6. The Teen Health Information Network (THINK).

    ERIC Educational Resources Information Center

    Kuzel, Judith; Erickson, Su

    1995-01-01

    Discusses the Teen Health Information Network (THINK), a grant-funded partnership of Aurora, Illinois, public libraries, schools, and community agencies to provide materials, information, and programming on issues related to teen health. Seven appendixes provide detailed information on survey results, collection evaluation and development,…

  7. Good Communication: The Other Social Network for Successful IT Organizations

    ERIC Educational Resources Information Center

    Trubitt, Lisa; Overholtzer, Jeff

    2009-01-01

    Social networks of the electronic variety have become thoroughly embedded in contemporary culture. People have woven these networks into their daily routines, using Facebook, Twitter, LinkedIn, online gaming environments, and other tools to build and maintain complex webs of professional and personal relationships. Chief Information Officers…

  8. Distributed wireless quantum communication networks with partially entangled pairs

    NASA Astrophysics Data System (ADS)

    Yu, Xu-Tao; Zhang, Zai-Chen; Xu, Jin

    2014-01-01

    Wireless quantum communication networks transfer quantum state by teleportation. Existing research focuses on maximal entangled pairs. In this paper, we analyse the distributed wireless quantum communication networks with partially entangled pairs. A quantum routing scheme with multi-hop teleportation is proposed. With the proposed scheme, is not necessary for the quantum path to be consistent with the classical path. The quantum path and its associated classical path are established in a distributed way. Direct multi-hop teleportation is conducted on the selected path to transfer a quantum state from the source to the destination. Based on the feature of multi-hop teleportation using partially entangled pairs, if the node number of the quantum path is even, the destination node will add another teleportation at itself. We simulated the performance of distributed wireless quantum communication networks with a partially entangled state. The probability of transferring the quantum state successfully is statistically analyzed. Our work shows that multi-hop teleportation on distributed wireless quantum networks with partially entangled pairs is feasible.

  9. A supervisory control policy over an acoustic communication network

    NASA Astrophysics Data System (ADS)

    Farhadi, Alireza; Dumon, Jonathan; Canudas-de-Wit, Carlos

    2015-05-01

    This paper presents a supervisory multi-agent control policy over an acoustic communication network subject to imperfections (packet dropout and transmission delay) for localisation of an underwater flow source (e.g., source of chemical pollution, fresh water, etc.) with an unknown location at the bottom of the ocean. A two-loop control policy combined with a coding strategy for reliable communication is presented to perform the above task. A simulator is developed and used to evaluate the trade-offs between quality of communication, transmission delay and control for a fleet of autonomous underwater vehicles supervised over a noisy acoustic communication network by an autonomous surface vessel. It is illustrated that without compensation of the effects of severe random packet dropout, localisation of an unknown underwater flow source is not possible for the condition simulated just by implementing a two-loop control policy. But a two-loop control policy combined with a strategy for reliable communication locates the unknown location of flow source.

  10. Exploration of Oral/Informal Technical Communications Behavior. Final Report.

    ERIC Educational Resources Information Center

    Graham, Warren R.; And Others

    The report explores and defines the boundaries of informal scientific and technological communication, based on data from scientists and engineers. A major purpose of the report was to determine the kinds of management decisions needed to enhance research productivity by improving informal research communication. The report includes: (1) a survey…

  11. Computing, Information, and Communications Technology (CICT) Program Overview

    NASA Technical Reports Server (NTRS)

    VanDalsem, William R.

    2003-01-01

    The Computing, Information and Communications Technology (CICT) Program's goal is to enable NASA's Scientific Research, Space Exploration, and Aerospace Technology Missions with greater mission assurance, for less cost, with increased science return through the development and use of advanced computing, information and communication technologies

  12. 31 CFR 542.306 - Information and communications technology.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... technology. 542.306 Section 542.306 Money and Finance: Treasury Regulations Relating to Money and Finance... Definitions § 542.306 Information and communications technology. The term information and communications technology means any hardware, software, or other product or service primarily intended to fulfill or...

  13. In backyards, on front lawns: examining informal risk communication and communicators.

    PubMed

    Rickard, Laura N

    2011-09-01

    Risk communicators are often envisioned as government officials, public relations practitioners, or health workers. Yet much of the public's risk information comes from informal messages and unofficial carriers. Referred to in this study as "informal risk communicators" (IRCs), these individuals are often service workers who relay risk information to public audiences, though often outside of their formal job descriptions. Literatures in the health communication, science and technology studies, and risk communication fields have considered ideas relevant to explaining these individuals, and the risk communication work they perform. To further explore this category of individuals, this study examines the communicative practices of commercial pesticide applicators, using both in-depth interviews and surveys. Through their interactions with clients, these individuals offer care, as well as project expertise and identity; however, the extent to which this work is recognized and validated is less clear. Both applied and theoretical implications of this research are considered. PMID:22164704

  14. Aerial networking communication solutions using Micro Air Vehicle (MAV)

    NASA Astrophysics Data System (ADS)

    Balasubramanian, Shyam; de Graaf, Maurits; Hoekstra, Gerard; Corporaal, Henk; Wijtvliet, Mark; Cuadros Linde, Javier

    2014-10-01

    The application of a Micro Air Vehicle (MAV) for wireless networking is slowly gaining significance in the field of network robotics. Aerial transport of data requires efficient network protocols along with accurate positional adjustment of the MAV to minimize transaction times. In our proof of concept, we develop an Aerial networking protocol for data transfer using the technology of Disruption Tolerant Networks (DTN), a store-and-forward approach for environments that deals with disrupted connectivity. Our results show that close interaction between networking and flight behavior helps in efficient data exchange. Potential applications are in areas where network infrastructure is minimal or unavailable and distances may be large. For example, forwarding video recordings during search and rescue, agriculture, swarm communication, among several others. A practical implementation and validation, as described in this paper, presents the complex dynamics of wireless environments and poses new challenges that are not addressed in earlier work on this topic. Several tests are evaluated in a practical setup to display the networking MAV behavior during such an operation.

  15. A Network for Physics Information.

    ERIC Educational Resources Information Center

    Koch, H. William; Herschman, Arthur

    The American Institute of Physics is working toward the development of a national information system for physics, whose objective is the organization of the flow of physics information from the producers to the users. The complete physics information system has several constituent subsystems, among which are: one for the management of the flow of…

  16. BOULDER AREA SUSTAINABILITY INFORMATION NETWORK (BASIN)

    EPA Science Inventory

    The primary goal of the Boulder Area Sustainability Information Network (BASIN) is to help citizens make meaningful connections between environmental data and their day-to-day activities and facilitate involvement in public policy development. Objectives include:

      ...

    • Scaling of data communications for an advanced supercomputer network

      NASA Technical Reports Server (NTRS)

      Levin, E.; Eaton, C. K.; Young, Bruce

      1986-01-01

      The goal of NASA's Numerical Aerodynamic Simulation (NAS) Program is to provide a powerful computational environment for advanced research and development in aeronautics and related disciplines. The present NAS system consists of a Cray 2 supercomputer connected by a data network to a large mass storage system, to sophisticated local graphics workstations and by remote communication to researchers throughout the United States. The program plan is to continue acquiring the most powerful supercomputers as they become available. The implications of a projected 20-fold increase in processing power on the data communications requirements are described.

    • Radar network communication through sensing of frequency hopping

      DOEpatents

      Dowla, Farid; Nekoogar, Faranak

      2013-05-28

      In one embodiment, a radar communication system includes a plurality of radars having a communication range and being capable of operating at a sensing frequency and a reporting frequency, wherein the reporting frequency is different than the sensing frequency, each radar is adapted for operating at the sensing frequency until an event is detected, each radar in the plurality of radars has an identification/location frequency for reporting information different from the sensing frequency, a first radar of the radars which senses the event sends a reporting frequency corresponding to its identification/location frequency when the event is detected, and all other radars in the plurality of radars switch their reporting frequencies to match the reporting frequency of the first radar upon detecting the reporting frequency switch of a radar within the communication range. In another embodiment, a method is presented for communicating information in a radar system.

    • Electronic Communication in Africa--the Promotion of Animal Health Information Dissemination.

      ERIC Educational Resources Information Center

      van der Westhuizen, Erica E.; Miller, E. Stan

      1995-01-01

      Discusses how the Veterinary Science Library at the University of Pretoria (South Africa) promotes electronic communication through various Internet and other network links. Provides a sample of online information sources available to veterinary teams and animal health workers, and a list of electronic addresses for South African libraries and…

    • The Implications of Information and Communications Technologies for Distance Education: Looking toward the Future. Final Report

      ERIC Educational Resources Information Center

      Arafeh, Sousan

      2004-01-01

      One salient factor of increasing interest in distance education is advancement in information and communications technologies (ICTs). In particular, digital and networked technologies have had a wide range of effects on the educational materials, practices, and institutions involved in education, notably by improving time-and cost-efficient…

  1. A Professional Development Project for Improving the Use of Information and Communication Technologies in Science Teaching

    ERIC Educational Resources Information Center

    Lavonen, Jari; Juuti, Kalle; Aksela, Maija; Meisalo, Veijo

    2006-01-01

    This article describes a professional development project aiming to develop practical approaches for the integration of information and communication technologies (ICT) into science education. Altogether, 13 two-day face-to-face seminars and numerous computer network conferences were held during a three-year period. The goals for the project were…

  2. The Internet, Political Communications Research and the Search for a New Information Paradigm

    ERIC Educational Resources Information Center

    Chiu, William Franklin

    2013-01-01

    The Internet, as a digital record of human discourse, provides an opportunity to directly analyze political communicative behavior. The rapid emergence of social online networks augurs a transformation in the quality and quantity of information people have to evaluate their political system. Digital formats instantiate new categories of actors and…

  3. Modern Aspects of Communication in Education of Teachers Using New Information and Communication Technologies (ICT)

    ERIC Educational Resources Information Center

    Tatkovic, Nevenka; Sehanovic, Jusuf; Ruzic, Maja

    2005-01-01

    This work deals with the need of introducing modern aspects of communication on higher education of future teachers using information and communication technologies. The emphasis is put on the importance for future teachers to have basic information science knowledge and skills and their preparations for using ICT. A growth of the number of…

  4. Balancing Ties: Boundary Spanning and Influence in the Organization's Extended Network of Communication.

    ERIC Educational Resources Information Center

    Manev, Ivan M.; Stevenson, William B.

    2001-01-01

    Presents a study of the business communication connecting an organization with others in its environment. Links boundary spanning with network theory and proposes the concept of an extended network of communication. Studies the relationship between boundary-spanning communication and individual influence in a network with 108 organizational…

  5. Self-Organized Information Processing in Neuronal Networks: Replacing Layers in Deep Networks by Dynamics

    NASA Astrophysics Data System (ADS)

    Kirst, Christoph

    It is astonishing how the sub-parts of a brain co-act to produce coherent behavior. What are mechanism that coordinate information processing and communication and how can those be changed flexibly in order to cope with variable contexts? Here we show that when information is encoded in the deviations around a collective dynamical reference state of a recurrent network the propagation of these fluctuations is strongly dependent on precisely this underlying reference. Information here 'surfs' on top of the collective dynamics and switching between states enables fast and flexible rerouting of information. This in turn affects local processing and consequently changes in the global reference dynamics that re-regulate the distribution of information. This provides a generic mechanism for self-organized information processing as we demonstrate with an oscillatory Hopfield network that performs contextual pattern recognition. Deep neural networks have proven to be very successful recently. Here we show that generating information channels via collective reference dynamics can effectively compress a deep multi-layer architecture into a single layer making this mechanism a promising candidate for the organization of information processing in biological neuronal networks.

  6. 78 FR 17418 - Rural Health Information Technology Network Development Grant

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-21

    ... HUMAN SERVICES Health Resources and Services Administration Rural Health Information Technology Network... award under the Rural Health Information Technology Network Development Grant (RHITND) to Grace... relinquishing its fiduciary responsibilities for the Rural Health Information Technology Network...

  7. Technology forecasting for space communication. [analysis of systems for application to Spacecraft Data and Tracking Network

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A study was conducted to determine techniques for application to space communication. The subjects considered are as follows: (1) optical communication systems, (2) laser communications for data acquisition networks, (3) spacecraft data rate requirements, (4) telemetry, command, and data handling, (5) spacecraft tracking and data network antenna and preamplifier cost tradeoff study, and (6) spacecraft communication terminal evaluation.

  8. Multiply-agile encryption in high speed communication networks

    SciTech Connect

    Pierson, L.G.; Witzke, E.L.

    1997-05-01

    Different applications have different security requirements for data privacy, data integrity, and authentication. Encryption is one technique that addresses these requirements. Encryption hardware, designed for use in high-speed communications networks, can satisfy a wide variety of security requirements if that hardware is key-agile, robustness-agile and algorithm-agile. Hence, multiply-agile encryption provides enhanced solutions to the secrecy, interoperability and quality of service issues in high-speed networks. This paper defines these three types of agile encryption. Next, implementation issues are discussed. While single-algorithm, key-agile encryptors exist, robustness-agile and algorithm-agile encryptors are still research topics.

  9. “We definitely need an audience”: experiences of Twitter, Twitter networks and tweet content in adults with severe communication disabilities who use augmentative and alternative communication (AAC)

    PubMed Central

    Hemsley, Bronwyn; Dann, Stephen; Palmer, Stuart; Allan, Meredith; Balandin, Susan

    2015-01-01

    Abstract Purpose: The aim of this study was to investigate the Twitter experiences of adults with severe communication disabilities who use augmentative and alternative communication (AAC) to inform Twitter training and further research on the use of Twitter in populations with communication disabilities. Method: This mixed methods research included five adults with severe communication disabilities who use AAC. It combined (a) quantitative analysis of Twitter networks and (b) manual coding of tweets with (c) narrative interviews with participants on their Twitter experiences and results. Results: The five participants who used AAC and Twitter were diverse in their patterns and experiences of using Twitter. Twitter networks reflected interaction with a close-knit network of people rather than with the broader publics on Twitter. Conversational, Broadcast and Pass Along tweets featured most prominently, with limited use of News or Social Presence tweets. Tweets appeared mostly within each participant's micro- or meso-structural layers of Twitter. Conclusions: People who use AAC report positive experiences in using Twitter. Obtaining help in Twitter, and engaging in hashtag communities facilitated higher frequency of tweets and establishment of Twitter networks. Results reflected an inter-connection of participant Twitter networks that might form part of a larger as yet unexplored emergent community of people who use AAC in Twitter.Implications for RehabilitationTwitter can be used as an important vehicle for conversation and a forum for people with communication disabilities to exchange information and participate socially in online communities.It is important that information and resources relating to the effective use of Twitter for a range of purposes are made available to people with communication disabilities who wish to take up or maintain use of Twitter.People with communication disabilities might benefit from support in using Twitter to meet their goals

  10. Successive lag synchronization on dynamical networks with communication delay

    NASA Astrophysics Data System (ADS)

    Xin-Jian, Zhang; Ai-Ju, Wei; Ke-Zan, Li

    2016-03-01

    In this paper, successive lag synchronization (SLS) on a dynamical network with communication delay is investigated. In order to achieve SLS on the dynamical network with communication delay, we design linear feedback control and adaptive control, respectively. By using the Lyapunov function method, we obtain some sufficient conditions for global stability of SLS. To verify these results, some numerical examples are further presented. This work may find potential applications in consensus of multi-agent systems. Project supported by the National Natural Science Foundation of China (Grant No. 61004101), the Natural Science Foundation Program of Guangxi Province, China (Grant No. 2015GXNSFBB139002), the Graduate Innovation Project of Guilin University of Electronic Technology, China (Grant No. GDYCSZ201472), and the Guangxi Colleges and Universities Key Laboratory of Data Analysis and Computation, Guilin University of Electronic Technology, China.

  11. Asymmetries in commitment in an avian communication network

    NASA Astrophysics Data System (ADS)

    Randler, Christoph; Vollmer, Christian

    2013-02-01

    Mobbing of predators occurs within a conspecific and heterospecific context but has not been quantified within the framework of a communication network and analysed with respect to heterospecific reciprocity. Here, we used playbacks of mobbing calls to show that mobbing is unequally distributed within a community of deciduous forest birds. Five species (great tit Parus major, blue tit Cyanistes caeruleus, marsh tit Poecile palustris, nuthatch Sitta europaea and chaffinch Fringilla coelebs) responded to each other's playbacks of mobbing calls. Commitment to mob was measured by minimum distance, response latency and uttering of calls. Commitment was higher when conspecific calls were broadcast. Yet, responses to heterospecific calls were significantly different between the five species. Chaffinches had the lowest commitment, and blue tits tended to have the highest. The communication network is asymmetric. Some species invest more than they receive from other species. As mobbing might incur costs, these are unequally distributed across the community.

  12. Asymmetries in commitment in an avian communication network.

    PubMed

    Randler, Christoph; Vollmer, Christian

    2013-02-01

    Mobbing of predators occurs within a conspecific and heterospecific context but has not been quantified within the framework of a communication network and analysed with respect to heterospecific reciprocity. Here, we used playbacks of mobbing calls to show that mobbing is unequally distributed within a community of deciduous forest birds. Five species (great tit Parus major, blue tit Cyanistes caeruleus, marsh tit Poecile palustris, nuthatch Sitta europaea and chaffinch Fringilla coelebs) responded to each other's playbacks of mobbing calls. Commitment to mob was measured by minimum distance, response latency and uttering of calls. Commitment was higher when conspecific calls were broadcast. Yet, responses to heterospecific calls were significantly different between the five species. Chaffinches had the lowest commitment, and blue tits tended to have the highest. The communication network is asymmetric. Some species invest more than they receive from other species. As mobbing might incur costs, these are unequally distributed across the community. PMID:23325292

  13. Program Support Communications Network (PSCN) facsimile system directory

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This directory provides a system description, a station listing, and operating procedures for the Program Support Communications Network (PSCN) NASA Facsimile System. The NASA Facsimile System is a convenient and efficient means of spanning the distance, time, and cost of transmitting documents from one person to another. In the spectrum of communication techniques, facsimile bridges the gap between mail and data transmission. Facsimile can transmit in a matter of minutes or seconds what would take a day or more by mail delivery. The NASA Facsimile System is composed of several makes and models of facsimile machines. The system also supports the 3M FaxXchange network controllers located at Marshall Space Flight Center (MSFC).

  14. Analysis of NASA communications (Nascom) II network protocols and performance

    NASA Technical Reports Server (NTRS)

    Omidyar, Guy C.; Butler, Thomas E.

    1991-01-01

    The NASA Communications (Nascom) Division of the Mission Operations and Data Systems Directorate is to undertake a major initiative to develop the Nascom II (NII) network to achieve its long-range service objectives for operational data transport to support the Space Station Freedom Program, the Earth Observing System, and other projects. NII is the Nascom ground communications network being developed to accommodate the operational traffic of the mid-1990s and beyond. The authors describe various baseline protocol architectures based on current and evolving technologies. They address the internetworking issues suggested for reliable transfer of data over heterogeneous segments. They also describe the NII architecture, topology, system components, and services. A comparative evaluation of the current and evolving technologies was made, and suggestions for further study are described. It is shown that the direction of the NII configuration and the subsystem component design will clearly depend on the advances made in the area of broadband integrated services.

  15. Modeling and Analysis of Mobility Management in Mobile Communication Networks

    PubMed Central

    Yoon, Ji Hyun; Kim, Chesoong

    2014-01-01

    Many strategies have been proposed to reduce the mobility management cost in mobile communication networks. This paper studies the zone-based registration methods that have been adopted by most mobile communication networks. We focus on two special zone-based registration methods, called two-zone registration (2Z) and two-zone registration with implicit registration by outgoing calls (2Zi). We provide a new mathematical model to analyze the exact performance of 2Z and 2Zi. We also present various numerical results, to compare the performance of 2Zi with those of 2Z and one-zone registration (1Z), and show that 2Zi is superior to 2Z as well as 1Z in most cases. PMID:24883368

  16. Influence of a network structure on the network effect in the communication service market

    NASA Astrophysics Data System (ADS)

    Uchida, Makoto; Shirayama, Susumu

    2008-09-01

    In this study, we analyze the network effect in a model of a personal communication market, by using a multi-agent based simulation approach. We introduce into the simulation model complex network structures as the interaction patterns of agents. With complex network models, we investigate the dynamics of a market in which two providers are competing. We also examine the structure of networks that affect the complex behavior of the market. By a series of simulations, we show that the structural properties of complex networks, such as the clustering coefficient and degree correlation, have a major influence on the dynamics of the market. We find that the network effect is increased if the interaction pattern of agents is characterized by a high clustering coefficient, or a positive degree correlation. We also discuss a suitable model of the interaction pattern for reproducing market dynamics in the real world, by performing simulations using real data of a social network.

  17. Wavelet neural network for detection of signals in communications

    NASA Astrophysics Data System (ADS)

    Gomez-Sanchez, Raquel; Andina, Diego

    1998-03-01

    Our objective is the design and simulation of an efficient system for detection of signals in communications in terms of speed and computational complexity. The proposed scheme takes advantage of two powerful frameworks in signal processing: wavelets and neural networks. The decision system will take a decision based on the computation of the a prior probabilities of the input signal. For the estimation of such probability density functions, a wavelet neural network has been chosen. The election has risen under the following considerations: (a) neural networks have been established as a general approximation tool for fitting nonlinear models from input/output data and (b) the increasing popularity of the wavelet decomposition as a powerful tool for approximation. The integration of the above factors leads to the wavelet neural network concept. This network preserves the universal approximation property of wavelet series, with the advantage of the speed and efficient computation of a neural network architecture. The topology and learning algorithm of the network will provide an efficient approximation to the required probability density functions.

  18. Gigabit Satellite Network for NASA's Advanced Communication Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    Hoder, Douglas; Bergamo, Marcos

    1996-01-01

    The advanced communication technology satellite (ACTS) gigabit satellite network provides long-haul point-to-point and point-to-multipoint full-duplex SONET services over NASA's ACTS. at rates up to 622 Mbit/s (SONET OC-12), with signal quality comparable to that obtained with terrestrial fiber networks. Data multiplexing over the satellite is accomplished using time-division multiple access (TDMA) techniques coordinated with the switching and beam hopping facilities provided by ACTS. Transmissions through the satellite are protected with Reed-Solomon encoding. providing virtually error-free transmission under most weather conditions. Unique to the system are a TDMA frame structure and satellite synchronization mechanism that allow: (a) very efficient utilization of the satellite capacity: (b) over-the-satellite dosed-loop synchronization of the network in configurations with up to 64 ground stations: and (c) ground station initial acquisition without collisions with existing signalling or data traffic. The user interfaces are compatible with SONET standards, performing the function of conventional SONET multiplexers and. as such. can be: readily integrated with standard SONET fiber-based terrestrial networks. Management of the network is based upon the simple network management protocol (SNMP). and includes an over-the-satellite signalling network and backup terrestrial internet (IP-based) connectivity. A description of the ground stations is also included.

  19. "I'll See You on IM, Text, or Call You": A Social Network Approach of Adolescents' Use of Communication Media

    ERIC Educational Resources Information Center

    Van Cleemput, Katrien

    2010-01-01

    This study explores some possibilities of social network analysis for studying adolescents' communication patterns. A full network analysis was conducted on third-grade high school students (15 year olds, 137 students) in Belgium. The results pointed out that face-to-face communication was still the most prominent way for information to flow…

  20. Performance analysis of Integrated Communication and Control System networks

    NASA Technical Reports Server (NTRS)

    Halevi, Y.; Ray, A.

    1990-01-01

    This paper presents statistical analysis of delays in Integrated Communication and Control System (ICCS) networks that are based on asynchronous time-division multiplexing. The models are obtained in closed form for analyzing control systems with randomly varying delays. The results of this research are applicable to ICCS design for complex dynamical processes like advanced aircraft and spacecraft, autonomous manufacturing plants, and chemical and processing plants.

  1. Technology developments integrating a space network communications testbed

    NASA Technical Reports Server (NTRS)

    Kwong, Winston; Jennings, Esther; Clare, Loren; Leang, Dee

    2006-01-01

    As future manned and robotic space explorations missions involve more complex systems, it is essential to verify, validate, and optimize such systems through simulation and emulation in a low cost testbed environment. The goal of such a testbed is to perform detailed testing of advanced space and ground communications networks, technologies, and client applications that are essential for future space exploration missions. We describe the development of new technologies enhancing our Multi-mission Advanced Communications Hybrid Environment for Test and Evaluation (MACHETE) that enables its integration in a distributed space communications testbed. MACHETE combines orbital modeling, link analysis, and protocol and service modeling to quantify system performance based on comprehensive considerations of different aspects of space missions.

  2. Intrusion-Tolerant Location Information Services in Intelligent Vehicular Networks

    NASA Astrophysics Data System (ADS)

    Yan, Gongjun; Yang, Weiming; Shaner, Earl F.; Rawat, Danda B.

    Intelligent Vehicular Networks, known as Vehicle-to-Vehicle and Vehicle-to-Roadside wireless communications (also called Vehicular Ad hoc Networks), are revolutionizing our daily driving with better safety and more infortainment. Most, if not all, applications will depend on accurate location information. Thus, it is of importance to provide intrusion-tolerant location information services. In this paper, we describe an adaptive algorithm that detects and filters the false location information injected by intruders. Given a noisy environment of mobile vehicles, the algorithm estimates the high resolution location of a vehicle by refining low resolution location input. We also investigate results of simulations and evaluate the quality of the intrusion-tolerant location service.

  3. Progress Toward Standards for the Seamless Interoperability of Broadband Satellite Communication Networks

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.; Glover, Daniel R.; vonDeak, Thomas C.; Bhasin, Kul B.

    1998-01-01

    The realization of the full potential of the National Information Infrastructure (NH) and Global Information Infrastructure (GII) requires seamless interoperability of emerging satellite networks with terrestrial networks. This requires a cooperative effort between industry, academia and government agencies to develop and advocate new, satellite-friendly communication protocols and modifications to existing communication protocol standards. These groups have recently come together to actively participating in a number of standards making bodies including: the Internet Engineering Task Force (IETF), the Asynchronous Transfer Mode (ATM) Forum, the International Telecommunication Union (ITU) and the Telecommunication Industry Association MA) to ensure that issues regarding efficient use of these protocols over satellite links are not overlooked. This paper will summarize the progress made toward standards development to achieve seamless integration and accelerate the deployment of multimedia applications.

  4. 76 FR 23812 - Reliability and Continuity of Communications Networks, Including Broadband Technologies; Effects...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-28

    ... Documents in Rulemaking Proceedings, 63 FR 24121 (1998). Electronic Filers: Comments may be filed... on Broadband Communications Networks of Damage or Failure of Network Equipment or Severe Overload...: Effects on Broadband Communications Networks of Damage or Failure of Network Equipment or Severe...

  5. Suppressing disease spreading by using information diffusion on multiplex networks

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Liu, Quan-Hui; Cai, Shi-Min; Tang, Ming; Braunstein, Lidia A.; Stanley, H. Eugene

    2016-07-01

    Although there is always an interplay between the dynamics of information diffusion and disease spreading, the empirical research on the systemic coevolution mechanisms connecting these two spreading dynamics is still lacking. Here we investigate the coevolution mechanisms and dynamics between information and disease spreading by utilizing real data and a proposed spreading model on multiplex network. Our empirical analysis finds asymmetrical interactions between the information and disease spreading dynamics. Our results obtained from both the theoretical framework and extensive stochastic numerical simulations suggest that an information outbreak can be triggered in a communication network by its own spreading dynamics or by a disease outbreak on a contact network, but that the disease threshold is not affected by information spreading. Our key finding is that there is an optimal information transmission rate that markedly suppresses the disease spreading. We find that the time evolution of the dynamics in the proposed model qualitatively agrees with the real-world spreading processes at the optimal information transmission rate.

  6. Suppressing disease spreading by using information diffusion on multiplex networks.

    PubMed

    Wang, Wei; Liu, Quan-Hui; Cai, Shi-Min; Tang, Ming; Braunstein, Lidia A; Stanley, H Eugene

    2016-01-01

    Although there is always an interplay between the dynamics of information diffusion and disease spreading, the empirical research on the systemic coevolution mechanisms connecting these two spreading dynamics is still lacking. Here we investigate the coevolution mechanisms and dynamics between information and disease spreading by utilizing real data and a proposed spreading model on multiplex network. Our empirical analysis finds asymmetrical interactions between the information and disease spreading dynamics. Our results obtained from both the theoretical framework and extensive stochastic numerical simulations suggest that an information outbreak can be triggered in a communication network by its own spreading dynamics or by a disease outbreak on a contact network, but that the disease threshold is not affected by information spreading. Our key finding is that there is an optimal information transmission rate that markedly suppresses the disease spreading. We find that the time evolution of the dynamics in the proposed model qualitatively agrees with the real-world spreading processes at the optimal information transmission rate. PMID:27380881

  7. Suppressing disease spreading by using information diffusion on multiplex networks

    PubMed Central

    Wang, Wei; Liu, Quan-Hui; Cai, Shi-Min; Tang, Ming; Braunstein, Lidia A.; Stanley, H. Eugene

    2016-01-01

    Although there is always an interplay between the dynamics of information diffusion and disease spreading, the empirical research on the systemic coevolution mechanisms connecting these two spreading dynamics is still lacking. Here we investigate the coevolution mechanisms and dynamics between information and disease spreading by utilizing real data and a proposed spreading model on multiplex network. Our empirical analysis finds asymmetrical interactions between the information and disease spreading dynamics. Our results obtained from both the theoretical framework and extensive stochastic numerical simulations suggest that an information outbreak can be triggered in a communication network by its own spreading dynamics or by a disease outbreak on a contact network, but that the disease threshold is not affected by information spreading. Our key finding is that there is an optimal information transmission rate that markedly suppresses the disease spreading. We find that the time evolution of the dynamics in the proposed model qualitatively agrees with the real-world spreading processes at the optimal information transmission rate. PMID:27380881

  8. Searching LOGIN, the Local Government Information Network.

    ERIC Educational Resources Information Center

    Jack, Robert F.

    1984-01-01

    Describes a computer-based information retrieval and electronic messaging system produced by Control Data Corporation now being used by government agencies and other organizations. Background of Local Government Information Network (LOGIN), database structure, types of LOGIN units, searching LOGIN (intersect, display, and list commands), and how…

  9. SCIENTIFIC AND TECHNICAL INFORMATION NETWORK (STN INTERNATIONAL)

    EPA Science Inventory

    STN International (the Scientific and Technical Information Network) offers both a fee based online search service that provides accurate, up-to-date, specific information from over 200 scientific, technical, business, and patent databases, and also fee based WWW access to select...

  10. Ohio Valley Community Health Information Network.

    ERIC Educational Resources Information Center

    Guard, Roger; And Others

    The Ohio Valley Community Health Information Network (OVCHIN) works to determine the efficacy of delivering health information to residents of rural southern Ohio and the urban and suburban Cincinnati area. OVCHIN is a community-based, consumer-defined demonstration grant program funded by the National Telecommunications and Information…

  11. Distributing Executive Information Systems through Networks.

    ERIC Educational Resources Information Center

    Penrod, James I.; And Others

    1993-01-01

    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,…

  12. Protecting Personal Information on Social Networking Sites

    ERIC Educational Resources Information Center

    Gallant, David T.

    2011-01-01

    Almost everyone uses social networking sites like Facebook, MySpace, and LinkedIn. Since Facebook is the most popular site in the history of the Internet, this article will focus on how one can protect his/her personal information and how that extends to protecting the private information of others.

  13. Impact of informal networks on opinion dynamics in hierarchically formal organization

    NASA Astrophysics Data System (ADS)

    Song, Xiao; Shi, Wen; Ma, Yaofei; Yang, Chen

    2015-10-01

    Traditional opinion dynamics model focused mainly on the conditions under which a group of agents would reach a consensus. Conclusion has been gained that continuous opinion dynamics are subject to the constraint that convergent opinion adjustment only proceeds when opinion difference is below a given tolerance. This conclusion is useful but neglected the fact that an organization often consists of overlapped networks including formally hierarchical network and small-world/scale-free informal networks. To study the impact of different types of informal networks on converging speed or the number of opinion clusters, four typical types of informal networks (small-world, scale-free, tree and fully connected) are modeled and proposed as complements to formal communications. Experiments to compare formal network and hybrid networks are then carried out. It is observed that opinion dynamics with supplemented communications of informal networks can benefit convergence speed and reduce opinion clusters. More importantly, it is revealed that three key factors of informal networks affect their impact on formal network. These factors of informal network in descending orders are: agents' tolerances, scale and number of links.

  14. Information transfer in community structured multiplex networks

    NASA Astrophysics Data System (ADS)

    Solé Ribalta, Albert; Granell, Clara; Gómez, Sergio; Arenas, Alex

    2015-08-01

    The study of complex networks that account for different types of interactions has become a subject of interest in the last few years, specially because its representational power in the description of users interactions in diverse online social platforms (Facebook, Twitter, Instagram, etc.). The mathematical description of these interacting networks has been coined under the name of multilayer networks, where each layer accounts for a type of interaction. It has been shown that diffusive processes on top of these networks present a phenomenology that cannot be explained by the naive superposition of single layer diffusive phenomena but require the whole structure of interconnected layers. Nevertheless, the description of diffusive phenomena on multilayer networks has obviated the fact that social networks have strong mesoscopic structure represented by different communities of individuals driven by common interests, or any other social aspect. In this work, we study the transfer of information in multilayer networks with community structure. The final goal is to understand and quantify, if the existence of well-defined community structure at the level of individual layers, together with the multilayer structure of the whole network, enhances or deteriorates the diffusion of packets of information.

  15. Pharmaceutical websites and the communication of risk information.

    PubMed

    Davis, Joel J; Cross, Emily; Crowley, John

    2007-01-01

    This study examines the pharmaceutical websites of 44 leading direct-to-consumer (DTC) advertised drugs to determine the extent to which risk information was completely communicated. Three operational definitions of "completeness" were used: communication of the single highest incidence side effect, communication of top three highest incidence side effects, and communication of side effects with incidence of >or= 10% (all measured in terms of absolute percentage). Results indicated that regardless of the measures used, pharmaceutical websites are unlikely to completely communicate risk information. About two thirds of all sites communicated the single highest incidence side effect or all top three side effects. For drugs with side effects at >or= 10% incidence, only about half of their websites fully reported all effects at this level of incidence. Implications for advertisers and regulatory agencies are presented. PMID:17365347

  16. An integrated multimedia medical information network system.

    PubMed

    Yamamoto, K; Makino, J; Sasagawa, N; Nagira, M

    1998-01-01

    An integrated multimedia medical information network system at Shimane Medical university has been developed to organize medical information generated from each section and provide information services useful for education, research and clinical practice. The report describes the outline of our system. It is designed to serve as a distributed database for electronic medical records and images. We are developing the MML engine that is to be linked to the world wide web (WWW) network system. To the users, this system will present an integrated multimedia representation of the patient records, providing access to both the image and text-based data required for an effective clinical decision making and medical education. PMID:10384445

  17. Clinical information systems for integrated healthcare networks.

    PubMed Central

    Teich, J. M.

    1998-01-01

    In the 1990's, a large number of hospitals and medical practices have merged to form integrated healthcare networks (IHN's). The nature of an IHN creates new demands for information management, and also imposes new constraints on information systems for the network. Important tradeoffs must be made between homogeneity and flexibility, central and distributed governance, and access and confidentiality. This paper describes key components of clinical information systems for IHN's, and examines important design decisions that affect the value of such systems. Images Figure 1 PMID:9929178

  18. A programmable analog VLSI neural network processor for communication receivers.

    PubMed

    Choi, J; Bang, S H; Sheu, B J

    1993-01-01

    An analog VLSI neural network processor was designed and fabricated for communication receiver applications. It does not require prior estimation of the channel characteristics. A powerful channel equalizer was implemented with this processor chip configured as a four-layered perceptron network. The compact synapse cell is realized with an enhanced wide-range Gilbert multiplier circuit. The output neuron consists of a linear current-to-voltage converter and a sigmoid function generator with a controllable voltage gain. Network training is performed by the modified Kalman neuro-filtering algorithm to speed up the convergence process for intersymbol interference and white Gaussian noise communication channels. The learning process is done in the companion DSP board which also keeps the synapse weight for later use of the chip. The VLSI neural network processor chip occupies a silicon area of 4.6 mmx6.8 mm and was fabricated in a 2-mum double-polysilicon CMOS technology. System analysis and experimental results are presented. PMID:18267752

  19. Online Communication and Information Technology Education

    ERIC Educational Resources Information Center

    Heinze, Aleksej; Procter, Chris

    2006-01-01

    Blended Learning, a learning facilitation that incorporates different modes of delivery, models of teaching, and learning styles, introduces multiple media to the dialog between the learner and the facilitator. This paper examines online communication as the link between established theory of learning and literature on e-learning in order to…

  20. Exploring challenges to telehealth communication by specialists in poison information.

    PubMed

    Rothwell, Erin; Ellington, Lee; Planalp, Sally; Crouch, Barbara

    2012-01-01

    The use of the telephone for providing health care is growing. A significant amount of social meaning is derived from visual information, and the absence of visual stimuli provides unique barriers to communication and increases the risks for misunderstandings and distractions. Understanding challenges to telephone communication can provide insight into training opportunities for overcoming these difficulties and improving patient care. The purpose of this research was to explore through focus groups the challenges of phone communication perceived by specialists in poison information. General types of challenges to effective phone communication included developing new communication skills to compensate for lack of visual information, difficulty assessing caller understanding, difficulty managing caller misunderstandings, maintaining distinctive assessments for routine calls, and managing the multifaceted aspects of job stress. The desire for training to enhance telehealth and cultural competency skills was also mentioned, and these findings might provide guidance for the development of training opportunities for telehealth professionals. PMID:21873282

  1. Information spreading on dynamic social networks

    NASA Astrophysics Data System (ADS)

    Liu, Chuang; Zhang, Zi-Ke

    2014-04-01

    Nowadays, information spreading on social networks has triggered an explosive attention in various disciplines. Most of previous works in this area mainly focus on discussing the effects of spreading probability or immunization strategy on static networks. However, in real systems, the peer-to-peer network structure changes constantly according to frequently social activities of users. In order to capture this dynamical property and study its impact on information spreading, in this paper, a link rewiring strategy based on the Fermi function is introduced. In the present model, the informed individuals tend to break old links and reconnect to their second-order friends with more uninformed neighbors. Simulation results on the susceptible-infected-recovered (SIR) model with fixed recovery time T=1 indicate that the information would spread more faster and broader with the proposed rewiring strategy. Extensive analyses of the information cascade size distribution show that the spreading process of the initial steps plays a very important role, that is to say, the information will spread out if it is still survival at the beginning time. The proposed model may shed some light on the in-depth understanding of information spreading on dynamical social networks.

  2. Weight-Control Information Network

    MedlinePlus

    ... Griffin Rodgers, Director of the NIDDK Clinical Trials Current research studies and how you can volunteer Community Outreach and Health Fairs Science-based information and tips for planning an outreach effort or community event For Health Care Professionals Patient and provider resources ...

  3. Fisheries Information Network in Indonesia.

    ERIC Educational Resources Information Center

    Balachandran, Sarojini

    During the early 1980s the Indonesian government made a policy decision to develop fisheries as an important sector of the national economy. In doing so, it recognized the need for the collection and dissemination of fisheries research information not only for the scientists themselves, but also for the ultimate transfer of technology through…

  4. Computerized and Networked Government Information.

    ERIC Educational Resources Information Center

    Stratford, Jean Slemmons; Stratford, Juri

    1998-01-01

    The United States has taken only piecemeal steps to ensure privacy of personal information. This article examines the U.S. relating to privacy and data protection. It defines privacy and discusses international agreements relating to privacy, federal data protection laws, and narrowly applicable laws. (AEF)

  5. Maximizing Information Diffusion in the Cyber-physical Integrated Network.

    PubMed

    Lu, Hongliang; Lv, Shaohe; Jiao, Xianlong; Wang, Xiaodong; Liu, Juan

    2015-01-01

    Nowadays, our living environment has been embedded with smart objects, such as smart sensors, smart watches and smart phones. They make cyberspace and physical space integrated by their abundant abilities of sensing, communication and computation, forming a cyber-physical integrated network. In order to maximize information diffusion in such a network, a group of objects are selected as the forwarding points. To optimize the selection, a minimum connected dominating set (CDS) strategy is adopted. However, existing approaches focus on minimizing the size of the CDS, neglecting an important factor: the weight of links. In this paper, we propose a distributed maximizing the probability of information diffusion (DMPID) algorithm in the cyber-physical integrated network. Unlike previous approaches that only consider the size of CDS selection, DMPID also considers the information spread probability that depends on the weight of links. To weaken the effects of excessively-weighted links, we also present an optimization strategy that can properly balance the two factors. The results of extensive simulation show that DMPID can nearly double the information diffusion probability, while keeping a reasonable size of selection with low overhead in different distributed networks. PMID:26569254

  6. Doctor-patient communication about cancer-related internet information.

    PubMed

    Bylund, Carma L; Gueguen, Jennifer A; D'Agostino, Thomas A; Li, Yuelin; Sonet, Ellen

    2010-01-01

    This article explores the effect of doctor-patient communication about cancer-related Internet information on self-reported outcomes. Two hundred and thirty cancer patients and caregivers completed an online survey regarding their experiences searching for and discussing with their doctors cancer-related Internet information. Participants who assertively introduced the Internet information in a consultation were more likely to have their doctor agree with the information. When doctors showed interest and involvement and took the information seriously, participants were less likely to report a desire to change the doctor's response. Taking the information seriously was also associated with greater satisfaction. This preliminary evidence that the doctor's response is associated with patient outcomes indicates the potential for improving patient-centered communication. In an effort to maximize patient-centered communication, doctors should be encouraged to take their patients and the information they present seriously, as well as show their patients that they are interested and involved. PMID:20391071

  7. Doctor–Patient Communication About Cancer-Related Internet Information

    PubMed Central

    BYLUND, CARMA L.; GUEGUEN, JENNIFER A.; D'AGOSTINO, THOMAS A.; LI, YUELIN; SONET, ELLEN

    2015-01-01

    This article explores the effect of doctor–patient communication about cancer-related Internet information on self-reported outcomes. Two hundred and thirty cancer patients and caregivers completed an online survey regarding their experiences searching for and discussing with their doctors cancer-related Internet information. Participants who assertively introduced the Internet information in a consultation were more likely to have their doctor agree with the information. When doctors showed interest and involvement and took the information seriously, participants were less likely to report a desire to change the doctor's response. Taking the information seriously was also associated with greater satisfaction. This preliminary evidence that the doctor's response is associated with patient outcomes indicates the potential for improving patient-centered communication. In an effort to maximize patient-centered communication, doctors should be encouraged to take their patients and the information they present seriously, as well as show their patients that they are interested and involved. PMID:20391071

  8. Informing Workers of Chemical Hazards: The OSHA Hazard Communication Standard.

    ERIC Educational Resources Information Center

    American Chemical Society, Washington, DC.

    Practical information on how to implement a chemical-related safety program is outlined in this publication. Highlights of the federal Occupational Safety and Health Administrations (OSHA) Hazard Communication Standard are presented and explained. These include: (1) hazard communication requirements (consisting of warning labels, material safety…

  9. Innovative Construction Training: Introducing Information Communication Technology into the Curriculum.

    ERIC Educational Resources Information Center

    Le Gallais, Tricia

    2001-01-01

    Research conducted to identify challenges associated with inclusion of information and communications technologies (ICT) in construction curriculum in a British college. ICT had the potential to provide cost effective and efficient training. However, human issues, including staff training, student access to equipment, and communication across the…

  10. A Common Public School Dilemma: When Information Proliferation Weakens Communication.

    ERIC Educational Resources Information Center

    Lalor, Francis R.

    1981-01-01

    Educators may find that thinking in ways that are self-reflective, strategic and tactical, imaginative, and social will tend to enhance their skill for engaging in the important process of human communication. It is doubtful that educators can communicatively organize themselves when an information overload exists. (CJ)

  11. Teaching Basic Communications Skills for an Information Society.

    ERIC Educational Resources Information Center

    LaConte, Ronald T.

    The flow of messages in the information age is no longer predominately down a chain of command but increasingly lateral. The modern communications process is also task specific, faster paced, more graphic and less verbal, and more technologically directed. These changes have rendered our definitions of communication skills and our school…

  12. Space Mobile Network: A Near Earth Communications and Navigation Architecture

    NASA Technical Reports Server (NTRS)

    Israel, David J.; Heckler, Gregory W.; Menrad, Robert J.

    2016-01-01

    This paper shares key findings of NASA's Earth Regime Network Evolution Study (ERNESt) team resulting from its 18-month effort to define a wholly new architecture-level paradigm for the exploitation of space by civil space and commercial sector organizations. Since the launch of Sputnik in October 1957 spaceflight missions have remained highly scripted activities from launch through disposal. The utilization of computer technology has enabled dramatic increases in mission complexity; but, the underlying premise that the diverse actions necessary to meet mission goals requires minute-by-minute scripting, defined weeks in advance of execution, for the life of the mission has remained. This archetype was appropriate for a "new frontier" but now risks overtly constraining the potential market-based opportunities for the innovation considered necessary to efficiently address the complexities associated with meeting communications and navigation requirements projected to be characteristics of the next era of space exploration: a growing number of missions in simultaneous execution, increased variance of mission types and growth in location/orbital regime diversity. The resulting ERNESt architectural cornerstone - the Space Mobile Network (SMN) - was envisioned as critical to creating an environment essential to meeting these future challenges in political, programmatic, technological and budgetary terms. The SMN incorporates technologies such as: Disruption Tolerant Networking (DTN) and optical communications, as well as new operations concepts such as User Initiated Services (UIS) to provide user services analogous to today's terrestrial mobile network user. Results developed in collaboration with NASA's Space Communications and Navigation (SCaN) Division and field centers are reported on. Findings have been validated via briefings to external focus groups and initial ground-based demonstrations. The SMN opens new niches for exploitation by the marketplace of mission

  13. Entropy measures for networks: toward an information theory of complex topologies.

    PubMed

    Anand, Kartik; Bianconi, Ginestra

    2009-10-01

    The quantification of the complexity of networks is, today, a fundamental problem in the physics of complex systems. A possible roadmap to solve the problem is via extending key concepts of information theory to networks. In this Rapid Communication we propose how to define the Shannon entropy of a network ensemble and how it relates to the Gibbs and von Neumann entropies of network ensembles. The quantities we introduce here will play a crucial role for the formulation of null models of networks through maximum-entropy arguments and will contribute to inference problems emerging in the field of complex networks. PMID:19905379

  14. The information age as a work in progress: Implications for technical communicators

    SciTech Connect

    Preecs, B.L.

    1992-07-01

    The commercial media system in the United States is in the midst of radical, even revolutionary changes. Cable television companies are vying with telephone companies to provide advanced communications and information services to both homes and businesses. Recent decisions by the Federal Communications Commission to allow television networks to buy cable television systems create the possibility of bypassing local television stations. Computer companies are planning joint ventures with entertainment companies. The publishing, broadcasting, advertising, communications, and information-services businesses are converging into one universal, digital, interactive industry with annual revenues exceeding $120 billion. The same technology-driven changes also affect government. State and local governments are experimenting with delivering some government services electronically. While early experiments focus on easily delivered services, such as auto licenses, more complex applications are underway, such as creating information networks for economic development or converting property and utility records into computerized maps. The Information Age has arrived, and the implications for Society for Technical Communication (STC) members can hardly be overstated. Technical communicators will face changes in the way they work and how their work is distributed.

  15. Community First Communication: Reversing Information Disparities to Achieve Environmental Justice

    PubMed Central

    Emmett, Edward A.; Desai, Chintan

    2011-01-01

    We address how information developed and effectively communicated through community based participatory research (CBPR) can reverse long-standing information disparities, empower a community, and be an agent for sustained change. Substantial information and power disparities existed between the polluted community and both the pollution industry and governmental regulators. An environmental justice partnership between a local community organization, physicians, and university performed CBPR and then developed a novel communication strategy to address a series of information disparities around a local water pollution issue. The community established a set of principles to govern the communication of results as soon as they were determined to be scientifically valid, including informing study participants and the community before other interested parties. CBPR results combined with a community-first communication strategy reversed the preexisting information disparities. The novel communication flow reversed the preferential information flow to industry and government associated with the usual scientific publication process. The community was empowered, and industry and government agencies responded positively to study recommendations. The CBPR results together with community first communication led to adoption of both community-wide and individual solutions and provided powerful motivation for behavioral change by industry and residents. PMID:21546988

  16. Implications of Information and Communication Technologies (ICT) for School-Home Communication

    ERIC Educational Resources Information Center

    Heath, Don; Maghrabi, Rozan; Carr, Nora

    2015-01-01

    Research demonstrates the positive impact of parental involvement on students, families and schools. Studies also indicate a close connection between effective school-home communication and increased parental involvement and engagement in learning. Effective selection and use of Information Communication Technologies (ICT) invites more effective…

  17. AC Electric Field Communication for Human-Area Networking

    NASA Astrophysics Data System (ADS)

    Kado, Yuichi; Shinagawa, Mitsuru

    We have proposed a human-area networking technology that uses the surface of the human body as a data transmission path and uses an AC electric field signal below the resonant frequency of the human body. This technology aims to achieve a “touch and connect” intuitive form of communication by using the electric field signal that propagates along the surface of the human body, while suppressing both the electric field radiating from the human body and mutual interference. To suppress the radiation field, the frequency of the AC signal that excites the transmitter electrode must be lowered, and the sensitivity of the receiver must be raised while reducing transmission power to its minimally required level. We describe how we are developing AC electric field communication technologies to promote the further evolution of a human-area network in support of ubiquitous services, focusing on three main characteristics, enabling-transceiver technique, application-scenario modeling, and communications quality evaluation. Special attention is paid to the relationship between electro-magnetic compatibility evaluation and regulations for extremely low-power radio stations based on Japan's Radio Law.

  18. Defining Information Needs of Computer Users: A Human Communication Problem.

    ERIC Educational Resources Information Center

    Kimbrough, Kenneth L.

    This exploratory investigation of the process of defining the information needs of computer users and the impact of that process on information retrieval focuses on communication problems. Six sites were visited that used computers to process data or to provide information, including the California Department of Transportation, the California…

  19. Assessing Information Literacy Instruction in the Basic Communication Course

    ERIC Educational Resources Information Center

    Meyer, Kevin R.; Hunt, Stephen K.; Hopper, K. Megan; Thakkar, Kashmira V.; Tsoubakopoulos, Vicky; Van Hoose, Kaylee J.

    2008-01-01

    Information literacy is becoming a key component of general education programs nationwide. As a critical part of most general education programs, the basic communication course is on the frontlines of the charge to teach information literacy skills to first-year students. Thus, the information literacy skills of basic course students should be…

  20. Geoscience communication in Namibia: YES Network Namibia spreading the message to young scientists

    NASA Astrophysics Data System (ADS)

    Mhopjeni, Kombada

    2015-04-01

    The Young Earth Scientists (YES) Network is an international association for early-career geoscientists under the age of 35 years that was formed as a result of the International Year of Planet Earth (IYPE) in 2007. YES Network aims to establish an interdisciplinary global network of early-career geoscientists to solve societal issues/challenges using geosciences, promote scientific research and interdisciplinary networking, and support professional development of early-career geoscientists. The Network has several National Chapters including one in Namibia. YES Network Namibia (YNN) was formed in 2009, at the closing ceremony of IYPE in Portugal and YNN was consolidated in 2013 with the current set-up. YNN supports the activities and goals of the main YES Network at national level providing a platform for young Namibian scientists with a passion to network, information on geoscience opportunities and promoting earth sciences. Currently most of the members are geoscientists from the Geological Survey of Namibia (GSN) and University of Namibia. In 2015, YNN plans to carry out two workshops on career guidance, establish a mentorship program involving alumni and experienced industry experts, and increase involvement in outreach activities, mainly targeting high school pupils. Network members will participate in a range of educational activities such as school career and science fairs communicating geoscience to the general public, learners and students. The community outreach programmes are carried out to increase awareness of the role geosciences play in society. In addition, YNN will continue to promote interactive collaboration between the University of Namibia, Geological Survey of Namibia (GSN) and Geological Society of Namibia. Despite the numerous potential opportunities YNN offers young scientists in Namibia and its presence on all major social media platforms, the Network faces several challenges. One notable challenge the Network faces is indifference among

  1. Information filtering in complex weighted networks

    NASA Astrophysics Data System (ADS)

    Radicchi, Filippo; Ramasco, José J.; Fortunato, Santo

    2011-04-01

    Many systems in nature, society, and technology can be described as networks, where the vertices are the system’s elements, and edges between vertices indicate the interactions between the corresponding elements. Edges may be weighted if the interaction strength is measurable. However, the full network information is often redundant because tools and techniques from network analysis do not work or become very inefficient if the network is too dense, and some weights may just reflect measurement errors and need to be be discarded. Moreover, since weight distributions in many complex weighted networks are broad, most of the weight is concentrated among a small fraction of all edges. It is then crucial to properly detect relevant edges. Simple thresholding would leave only the largest weights, disrupting the multiscale structure of the system, which is at the basis of the structure of complex networks and ought to be kept. In this paper we propose a weight-filtering technique based on a global null model [Global Statistical Significance (GloSS) filter], keeping both the weight distribution and the full topological structure of the network. The method correctly quantifies the statistical significance of weights assigned independently to the edges from a given distribution. Applications to real networks reveal that the GloSS filter is indeed able to identify relevant connections between vertices.

  2. Country-wide rainfall maps from cellular communication networks

    PubMed Central

    Overeem, Aart; Leijnse, Hidde; Uijlenhoet, Remko

    2013-01-01

    Accurate and timely surface precipitation measurements are crucial for water resources management, agriculture, weather prediction, climate research, as well as ground validation of satellite-based precipitation estimates. However, the majority of the land surface of the earth lacks such data, and in many parts of the world the density of surface precipitation gauging networks is even rapidly declining. This development can potentially be counteracted by using received signal level data from the enormous number of microwave links used worldwide in commercial cellular communication networks. Along such links, radio signals propagate from a transmitting antenna at one base station to a receiving antenna at another base station. Rain-induced attenuation and, subsequently, path-averaged rainfall intensity can be retrieved from the signal’s attenuation between transmitter and receiver. Here, we show how one such a network can be used to retrieve the space–time dynamics of rainfall for an entire country (The Netherlands, ∼35,500 km2), based on an unprecedented number of links (∼2,400) and a rainfall retrieval algorithm that can be applied in real time. This demonstrates the potential of such networks for real-time rainfall monitoring, in particular in those parts of the world where networks of dedicated ground-based rainfall sensors are often virtually absent. PMID:23382210

  3. Country-wide rainfall maps from cellular communication networks.

    PubMed

    Overeem, Aart; Leijnse, Hidde; Uijlenhoet, Remko

    2013-02-19

    Accurate and timely surface precipitation measurements are crucial for water resources management, agriculture, weather prediction, climate research, as well as ground validation of satellite-based precipitation estimates. However, the majority of the land surface of the earth lacks such data, and in many parts of the world the density of surface precipitation gauging networks is even rapidly declining. This development can potentially be counteracted by using received signal level data from the enormous number of microwave links used worldwide in commercial cellular communication networks. Along such links, radio signals propagate from a transmitting antenna at one base station to a receiving antenna at another base station. Rain-induced attenuation and, subsequently, path-averaged rainfall intensity can be retrieved from the signal's attenuation between transmitter and receiver. Here, we show how one such a network can be used to retrieve the space-time dynamics of rainfall for an entire country (The Netherlands, ∼35,500 km(2)), based on an unprecedented number of links (∼2,400) and a rainfall retrieval algorithm that can be applied in real time. This demonstrates the potential of such networks for real-time rainfall monitoring, in particular in those parts of the world where networks of dedicated ground-based rainfall sensors are often virtually absent. PMID:23382210

  4. Mixed Integer Programming and Heuristic Scheduling for Space Communication Networks

    NASA Technical Reports Server (NTRS)

    Cheung, Kar-Ming; Lee, Charles H.

    2012-01-01

    We developed framework and the mathematical formulation for optimizing communication network using mixed integer programming. The design yields a system that is much smaller, in search space size, when compared to the earlier approach. Our constrained network optimization takes into account the dynamics of link performance within the network along with mission and operation requirements. A unique penalty function is introduced to transform the mixed integer programming into the more manageable problem of searching in a continuous space. The constrained optimization problem was proposed to solve in two stages: first using the heuristic Particle Swarming Optimization algorithm to get a good initial starting point, and then feeding the result into the Sequential Quadratic Programming algorithm to achieve the final optimal schedule. We demonstrate the above planning and scheduling methodology with a scenario of 20 spacecraft and 3 ground stations of a Deep Space Network site. Our approach and framework have been simple and flexible so that problems with larger number of constraints and network can be easily adapted and solved.

  5. QoS management for the next mobile communication network

    NASA Astrophysics Data System (ADS)

    Wang, Hui; Lu, Jun; Yu, Jianwei; He, Feng

    2004-04-01

    With convergence of network technologies, future network infrastructure will be based on IP and traditional wireless/mobile networks will also evolve inevitably to a unified all-IP mobile internet which can support voice, data and video simultaneously. But, the pattern served by IP is best effort. So IP mobility and QoS management have been the main challenges of all-IP mobile networks. Based on Mobile IP, IP QoS protocol, etc, ... The paper brings forward an end-to-end QoS management solution for the next mobile communication network, introduces a terminology of QoS Agent Server (QAS), which acts as resource manage server and participate in dynamic Service Level Specification (SLS) negotiation with mobile hosts (MH) or other QAS. Taking advantage of the mechanisms, discussed the process of QoS manage to support mobile hosts' fast handoff between cells. Additionally, adopted and self-adaptive control algorithm for non-real time service on interior nodes. Finally, conclusions are given and possible future works are described.

  6. Clustering and Beamforming for Efficient Communication in Wireless Sensor Networks.

    PubMed

    Porcel-Rodríguez, Francisco; Valenzuela-Valdés, Juan; Padilla, Pablo; Luna-Valero, Francisco; Luque-Baena, Rafael; López-Gordo, Miguel Ángel

    2016-01-01

    Energy efficiency is a critical issue for wireless sensor networks (WSNs) as sensor nodes have limited power availability. In order to address this issue, this paper tries to maximize the power efficiency in WSNs by means of the evaluation of WSN node networks and their performance when both clustering and antenna beamforming techniques are applied. In this work, four different scenarios are defined, each one considering different numbers of sensors: 50, 20, 10, five, and two nodes per scenario, and each scenario is randomly generated thirty times in order to statistically validate the results. For each experiment, two different target directions for transmission are taken into consideration in the optimization process (φ = 0° and θ = 45°; φ = 45°, and θ = 45°). Each scenario is evaluated for two different types of antennas, an ideal isotropic antenna and a conventional dipole one. In this set of experiments two types of WSN are evaluated: in the first one, all of the sensors have the same amount of power for communications purposes; in the second one, each sensor has a different amount of power for its communications purposes. The analyzed cases in this document are focused on 2D surface and 3D space for the node location. To the authors' knowledge, this is the first time that beamforming and clustering are simultaneously applied to increase the network lifetime in WSNs. PMID:27556463

  7. Improving stochastic communication network performance: Reliability vs throughput

    NASA Astrophysics Data System (ADS)

    Jansen, Leonard J.

    1991-12-01

    This research investigated the measurement and improvement of two performance parameters, expected flow and reliability, for stochastic communication networks. There were three objectives of this research. The first was to measure the reliability of large stochastic networks. This was accomplished through an investigation into the current methodologies in the literature, with a subsequent selection and application of a factoring program developed by Page and Perry. The second objective was to develop a reliability improvement model given that a mathematical reliability expression did not exist. This was accomplished modeling a heuristic by Jain and Gopal, into a linear improvement model. Finally, the third objective was to examine the trade-off between maximizing expected flow and reliability. This was accomplished through generating bounds for the efficient frontier in a modified multicriteria optimization approach. Using the methodologies formulated in this research, the performance parameters of both expected flow and reliability can be measured and subsequent improvements made providing insight into the operational capabilities of stochastic communication networks.

  8. Innovative Networking Concepts Tested on the Advanced Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

    Friedman, Daniel; Gupta, Sonjai; Zhang, Chuanguo; Ephremides, Anthony

    1996-01-01

    This paper describes a program of experiments conducted over the advanced communications technology satellite (ACTS) and the associated TI-VSAT (very small aperture terminal). The experiments were motivated by the commercial potential of low-cost receive only satellite terminals that can operate in a hybrid network environment, and by the desire to demonstrate frame relay technology over satellite networks. The first experiment tested highly adaptive methods of satellite bandwidth allocation in an integrated voice-data service environment. The second involved comparison of forward error correction (FEC) and automatic repeat request (ARQ) methods of error control for satellite communication with emphasis on the advantage that a hybrid architecture provides, especially in the case of multicasts. Finally, the third experiment demonstrated hybrid access to databases and compared the performance of internetworking protocols for interconnecting local area networks (LANs) via satellite. A custom unit termed frame relay access switch (FRACS) was developed by COMSAT Laboratories for these experiments; the preparation and conduct of these experiments involved a total of 20 people from the University of Maryland, the University of Colorado and COMSAT Laboratories, from late 1992 until 1995.

  9. Minimum energy information fusion in sensor networks

    SciTech Connect

    Chapline, G

    1999-05-11

    In this paper we consider how to organize the sharing of information in a distributed network of sensors and data processors so as to provide explanations for sensor readings with minimal expenditure of energy. We point out that the Minimum Description Length principle provides an approach to information fusion that is more naturally suited to energy minimization than traditional Bayesian approaches. In addition we show that for networks consisting of a large number of identical sensors Kohonen self-organization provides an exact solution to the problem of combing the sensor outputs into minimal description length explanations.

  10. A Mathematical Model of the Effects of Internal Group Pressures, of Group Communication, and of Out-Group Communication on Attitude Change in Human Communication Networks.

    ERIC Educational Resources Information Center

    Johnson, J. David

    A mathematical model that describes attitude change in human communication networks is developed in this paper. The parameters of the model are drawn from a review of the literature related to network analysis, small group influence, mass communication, and attitude change. The literature review identifies key variables that influence attitude…

  11. Deep Space Network and Lunar Network Communication Coverage of the Moon

    NASA Technical Reports Server (NTRS)

    Lee, Charles H.; Cheung, Kar-Ming

    2006-01-01

    In this article, we describe the communication coverage analysis for the lunar network and the Earth ground stations. The first part of this article focuses on the direct communication coverage of the Moon from the Earth's ground stations. In particular, we assess the coverage performance of the Moon based on the existing Deep Space Network (DSN) antennas and the complimentary coverage of other potential stations at Hartebeesthoek, South Africa and at Santiago, Chile. We also address the coverage sensitivity based on different DSN antenna scenarios and their capability to provide single and redundant coverage of the Moon. The second part of this article focuses on the framework of the constrained optimization scheme to seek a stable constellation six relay satellites in two planes that not only can provide continuous communication coverage to any users on the Moon surface, but can also deliver data throughput in a highly efficient manner.

  12. Destination-directed, packet-switched architecture for a geostationary communications satellite network

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.; Shalkhauser, Mary JO; Bobinsky, Eric A.; Soni, Nitin J.; Quintana, Jorge A.; Kim, Heechul; Wager, Paul; Vanderaar, Mark

    1993-01-01

    A major goal of the Digital Systems Technology Branch at the NASA Lewis Research Center is to identify and develop critical digital components and technologies that either enable new commercial missions or significantly enhance the performance, cost efficiency, and/or reliability of existing and planned space communications systems. NASA envisions a need for low-data-rate, interactive, direct-to-the-user communications services for data, voice, facsimile, and video conferencing. The network would provide enhanced very-small-aperture terminal (VSAT) communications services and be capable of handling data rates of 64 kbps through 2.048 Mbps in 64-kbps increments. Efforts have concentrated heavily on the space segment; however, the ground segment has been considered concurrently to ensure cost efficiency and realistic operational constraints. The focus of current space segment developments is a flexible, high-throughput, fault-tolerant onboard information-switching processor (ISP) for a geostationary satellite communications network. The Digital Systems Technology Branch is investigating both circuit and packet architectures for the ISP. Destination-directed, packet-switched architectures for geostationary communications satellites are addressed.

  13. Secure and Authenticated Data Communication in Wireless Sensor Networks

    PubMed Central

    Alfandi, Omar; Bochem, Arne; Kellner, Ansgar; Göge, Christian; Hogrefe, Dieter

    2015-01-01

    Securing communications in wireless sensor networks is increasingly important as the diversity of applications increases. However, even today, it is equally important for the measures employed to be energy efficient. For this reason, this publication analyzes the suitability of various cryptographic primitives for use in WSNs according to various criteria and, finally, describes a modular, PKI-based framework for confidential, authenticated, secure communications in which most suitable primitives can be employed. Due to the limited capabilities of common WSN motes, criteria for the selection of primitives are security, power efficiency and memory requirements. The implementation of the framework and the singular components have been tested and benchmarked in our testbed of IRISmotes. PMID:26266413

  14. Secure Many-to-One Communications in Wireless Sensor Networks

    PubMed Central

    Viejo, Alexandre; Domingo-Ferrer, Josep; Sebé, Francesc; Castellà-Roca, Jordi

    2009-01-01

    Wireless Sensor Networks (WSN) are formed by nodes with limited computational and power resources. WSNs are finding an increasing number of applications, both civilian and military, most of which require security for the sensed data being collected by the base station from remote sensor nodes. In addition, when many sensor nodes transmit to the base station, the implosion problem arises. Providing security measures and implosion-resistance in a resource-limited environment is a real challenge. This article reviews the aggregation strategies proposed in the literature to handle the bandwidth and security problems related to many-to-one transmission in WSNs. Recent contributions to secure lossless many-to-one communication developed by the authors in the context of several Spanish-funded projects are surveyed. Ongoing work on the secure lossy many-to-one communication is also sketched. PMID:22346700

  15. 20/30 GHz satellite personal communications networks

    NASA Technical Reports Server (NTRS)

    Palmer, L. C.; Stern, A.; Sohn, P. Y.

    1992-01-01

    The feasibility of personal communications networks that can provide 4.8-kbps voice communications between portable terminals and a hub station via a Ka-band geosynchronous satellite has been investigated. Tradeoffs are examined so that the combined system of hub and gateway earth stations, the satellite, and the personal terminals can provide a competitive service in terms of cost, availability, and quality. A baseline system is described using a spacecraft with approximately 140 spot beams that cover CONUS with 5-watt power amplifiers in each beam. Satellite access in both the forward and return directions uses frequency division multiple access/code division multiple access with a chip rate of 2.5 Mchip/sec.

  16. A personal communications network using a Ka-band satellite

    NASA Technical Reports Server (NTRS)

    Palmer, Larry C.; Laborde, Enrique; Stern, Alan; Sohn, Philip Y.

    1992-01-01

    The feasibility of a personal communications network using portable terminals that can provide 4.8-kb/s voice communications to a hub station via a Ka-band geosynchronous satellite has been investigated. Tradeoffs are examined so that the combined system of hub and gateway earth stations, the satellite, and the personal terminals can provide a competitive service in terms of cost, availability, and quality. A baseline system that uses a spacecraft with approximately 140 spot beams to cover the contiguous US (CONUS) and 5-W power amplifiers in each beam is described. Satellite access in both the forward and return directions uses frequency-division multiple-access/code-division multiple-access (FDMA/CDMA) with a chip rate of 2.5 Mchip/s.

  17. Secure and Authenticated Data Communication in Wireless Sensor Networks.

    PubMed

    Alfandi, Omar; Bochem, Arne; Kellner, Ansgar; Göge, Christian; Hogrefe, Dieter

    2015-01-01

    Securing communications in wireless sensor networks is increasingly important as the diversity of applications increases. However, even today, it is equally important for the measures employed to be energy efficient. For this reason, this publication analyzes the suitability of various cryptographic primitives for use in WSNs according to various criteria and, finally, describes a modular, PKI-based framework for confidential, authenticated, secure communications in which most suitable primitives can be employed. Due to the limited capabilities of common WSN motes, criteria for the selection of primitives are security, power efficiency and memory requirements. The implementation of the framework and the singular components have been tested and benchmarked in our testbed of IRISmotes. PMID:26266413

  18. 10 CFR 73.54 - Protection of digital computer and communication systems and networks.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Protection of digital computer and communication systems... computer and communication systems and networks. By November 23, 2009 each licensee currently licensed to... provide high assurance that digital computer and communication systems and networks are...

  19. 10 CFR 73.54 - Protection of digital computer and communication systems and networks.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 2 2012-01-01 2012-01-01 false Protection of digital computer and communication systems... computer and communication systems and networks. By November 23, 2009 each licensee currently licensed to... provide high assurance that digital computer and communication systems and networks are...

  20. 10 CFR 73.54 - Protection of digital computer and communication systems and networks.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 2 2014-01-01 2014-01-01 false Protection of digital computer and communication systems... computer and communication systems and networks. By November 23, 2009 each licensee currently licensed to... provide high assurance that digital computer and communication systems and networks are...