WorldWideScience

Sample records for strong communication network

  1. Promoting Strong Written Communication Skills

    Science.gov (United States)

    Narayanan, M.

    2015-12-01

    The reason that an improvement in the quality of technical writing is still needed in the classroom is due to the fact that universities are facing challenging problems not only on the technological front but also on the socio-economic front. The universities are actively responding to the changes that are taking place in the global consumer marketplace. Obviously, there are numerous benefits of promoting strong written communication skills. They can be summarized into the following six categories. First, and perhaps the most important: The University achieves learner satisfaction. The learner has documented verbally, that the necessary knowledge has been successfully acquired. This results in learner loyalty that in turn will attract more qualified learners.Second, quality communication lowers the cost per pupil, consequently resulting in increased productivity backed by a stronger economic structure and forecast. Third, quality communications help to improve the cash flow and cash reserves of the university. Fourth, having high quality communication enables the university to justify the need for high costs of tuition and fees. Fifth, better quality in written communication skills result in attracting top-quality learners. This will lead to happier and satisfied learners, not to mention greater prosperity for the university as a whole. Sixth, quality written communication skills result in reduced complaints, thus meaning fewer hours spent on answering or correcting the situation. The University faculty and staff are thus able to devote more time on scholarly activities, meaningful research and productive community service. References Boyer, Ernest L. (1990). Scholarship reconsidered: Priorities of the Professorate.Princeton, NJ: Carnegie Foundation for the Advancement of Teaching. Hawkins, P., & Winter, J. (1997). Mastering change: Learning the lessons of the enterprise.London: Department for Education and Employment. Buzzel, Robert D., and Bradley T. Gale. (1987

  2. Field Bus Communications Network

    International Nuclear Information System (INIS)

    Kwon, Uk Hyeon; Kim, Hyeong Seok; Kim, Dong Seong

    2004-10-01

    This book is about field bus communications network, introducing data communications network, field bus for industry and standardization of communication protocol, basic of data communication about structure, local area network, introduction of field bus for industry like utility of field bus, profibus, foundation field bus, worldFIP, device net, inter bus, control net, P-net and SERCOS, evaluation of field bus performance including computer simulation tool, and network modeling, and field bus practice.

  3. Communication network exchange

    International Nuclear Information System (INIS)

    Woo, Seung Sul

    1988-05-01

    This book has two parts. The first parts is comprised of five chapters, which deals with communication network constitution with design of network and types, telephone network about outline and management of network, telephone network · data network · private network, international data telephone network about service and international data network and technical standards of quality of service, communication and data. The second parts handles exchange, which is about institution of switching, a manual exchange and step-by step exchange, a crossbar exchange, electronic exchange, international switching system, design of equipment of test and measurement.

  4. Knowledge in Communication Networks

    OpenAIRE

    Naumov, Pavel; Tao, Jia

    2015-01-01

    The paper investigates epistemic properties of information flow under communication protocols with a given topological structure of the communication network. The main result is a sound and complete logical system that describes all such properties. The system consists of a variation of the multi-agent epistemic logic S5 extended by a new network-specific Gateway axiom.

  5. Computer-communication networks

    CERN Document Server

    Meditch, James S

    1983-01-01

    Computer- Communication Networks presents a collection of articles the focus of which is on the field of modeling, analysis, design, and performance optimization. It discusses the problem of modeling the performance of local area networks under file transfer. It addresses the design of multi-hop, mobile-user radio networks. Some of the topics covered in the book are the distributed packet switching queuing network design, some investigations on communication switching techniques in computer networks and the minimum hop flow assignment and routing subject to an average message delay constraint

  6. Designing for Networked Communications

    DEFF Research Database (Denmark)

    Designing for Networked Communications: Strategies and Development explains how to plan, use, and understand the products and the dynamic social processes and tasks some of the most vital innovations in the knowledge society depend upon– social as well as technological. Focusing on various forms...... and important research in a variety of forms for networked communications. A constructive and critical view of the interplay between the new electronic and the more conventional modes of communication are utilized, while studies of organizational work practices demonstrate that the use of new technologies...... of design, implementation and integration of computer mediated communication, this book bridges the academic fields of computer science and communication studies. Designing for Networked Communications: Strategies and Development uses an interdisciplinary approach, and presents results from recent...

  7. Designing for Networked Communications

    DEFF Research Database (Denmark)

    Designing for Networked Communications: Strategies and Development explains how to plan, use, and understand the products and the dynamic social processes and tasks some of the most vital innovations in the knowledge society depend upon– social as well as technological. Focusing on various forms...... of design, implementation and integration of computer mediated communication, this book bridges the academic fields of computer science and communication studies. Designing for Networked Communications: Strategies and Development uses an interdisciplinary approach, and presents results from recent...... and important research in a variety of forms for networked communications. A constructive and critical view of the interplay between the new electronic and the more conventional modes of communication are utilized, while studies of organizational work practices demonstrate that the use of new technologies...

  8. NASA Communications Augmentation network

    Science.gov (United States)

    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.

  9. NASA Communications Augmentation network

    Science.gov (United States)

    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.

  10. Decomposition of Network Communication Games

    NARCIS (Netherlands)

    Dietzenbacher, Bas; Borm, Peter; Hendrickx, Ruud

    2015-01-01

    Using network control structures this paper introduces network communication games as a generalization of vertex games and edge games corresponding to communication situations and studies their decomposition into unanimity games. We obtain a relation between the dividends of the network

  11. RELATIONSHIPS AND COMMUNICATION NETWORKS

    OpenAIRE

    Stefan VLADUTESCU

    2012-01-01

    The main feature of the present situation regarding communication is the impregnation of the social with technology. Computer-mediated communication systems has led to the crystallization of a strong specific interactions. This article describes how human relationships constitues the ontological pillar of society and social relations form the axis irradiance of sociology. Overall, as social agents in social space, people come in a variety of social relationships. Thus, a distinct note of the ...

  12. European environmental communication networks

    International Nuclear Information System (INIS)

    Plesnikova, T.

    2005-01-01

    The goal of this presentation is apprise of special community - representatives of state and public administration, self-administration, workers of scientific institutes, schools, private companies and next privies subjects of areas of the environment with possibilities of access to actual environmental information by the Internet. Web-sites of environmental communication networks with data about the environment are presented

  13. The lung communication network.

    Science.gov (United States)

    Losa, Davide; Chanson, Marc

    2015-08-01

    The different types of cells in the lung, from the conducting airway epithelium to the alveolar epithelium and the pulmonary vasculature, are interconnected by gap junctions. The specific profile of gap junction proteins, the connexins, expressed in these different cell types forms compartments of intercellular communication that can be further shaped by the release of extracellular nucleotides via pannexin1 channels. In this review, we focus on the physiology of connexins and pannexins and describe how this lung communication network modulates lung function and host defenses in conductive and respiratory airways.

  14. Decomposition of network communication games

    NARCIS (Netherlands)

    Dietzenbacher, Bas; Borm, Peter; Hendrickx, Ruud

    Using network control structures, this paper introduces a general class of network communication games and studies their decomposition into unanimity games. We obtain a relation between the dividends in any network communication game and its underlying transferable utility game, which depends on the

  15. Communication in Animal Social Networks

    NARCIS (Netherlands)

    Snijders, Lysanne; Naguib, Marc

    2017-01-01

    Animal social networks and animal communication networks are key disciplines for understanding animal social behavior, yet these disciplines remain poorly integrated. In this review, we show how communication and social networks are inherently linked, with social signals reflecting and affecting

  16. SOCIAL NETWORKS AND INTERPERSONAL COMMUNICATION

    Directory of Open Access Journals (Sweden)

    Veronica GHEORGHIȚĂ

    2014-11-01

    Full Text Available Social networks visible influence people's ability to interact and communicate. Extending social circles by establishing virtual links involves a number of positive aspects such as: instant access to options for interaction, sharing of information to large communities of people, intensification of acts of communication, high levels of feedback and trust with people with whom we communicate. On the other hand, social networks adversely affects communication by decreasing the interaction face to face, by imposing superficial communications experiences, grammatical and spelling erosion of the language. Therefore, the study aims to capture the spread of social networks, their use and impact on interpersonal communication. More specifically, they look for the answer to the question: what is the nature of interpersonal communication that is found on social networking sites: personal, emotional, private or shared, informal, and public?

  17. Complex Dynamics in Communication Networks

    CERN Document Server

    Kocarev, Ljupco

    2005-01-01

    Computer and communication networks are among society's most important infrastructures. The internet, in particular, is a giant global network of networks without central control or administration. It is a paradigm of a complex system, where complexity may arise from different sources: topological structure, network evolution, connection and node diversity, or dynamical evolution. The present volume is the first book entirely devoted to the new and emerging field of nonlinear dynamics of TCP/IP networks. It addresses both scientists and engineers working in the general field of communication networks.

  18. Topological Rankings in Communication Networks

    DEFF Research Database (Denmark)

    Aabrandt, Andreas; Hansen, Vagn Lundsgaard; Træholt, Chresten

    2015-01-01

    In the theory of communication the central problem is to study how agents exchange information. This problem may be studied using the theory of connected spaces in topology, since a communication network can be modelled as a topological space such that agents can communicate if and only...... if they belong to the same path connected component of that space. In order to study combinatorial properties of such a communication network, notions from algebraic topology are applied. This makes it possible to determine the shape of a network by concrete invariants, e.g. the number of connected components...

  19. Towards Integrated Marmara Strong Motion Network

    Science.gov (United States)

    Durukal, E.; Erdik, M.; Safak, E.; Ansal, A.; Ozel, O.; Alcik, H.; Mert, A.; Kafadar, N.; Korkmaz, A.; Kurtulus, A.

    2009-04-01

    Istanbul has a 65% chance of having a magnitude 7 or above earthquake within the next 30 years. As part of the preparations for the future earthquake, strong motion networks have been installed in and around Istanbul. The Marmara Strong Motion Network, operated by the Department of Earthquake Engineering of Kandilli Observatory and Earthquake Research Institute, encompasses permanent systems outlined below. It is envisaged that the networks will be run by a single entity responsible for technical management and maintanence, as well as for data management, archiving and dissemination through dedicated web-based interfaces. • Istanbul Earthquake Rapid Response and Early Warning System - IERREWS (one hundred 18-bit accelerometers for rapid response; ten 24-bit accelerometers for early warning) • IGDAŞ Gas Shutoff Network (100 accelerometers to be installed in 2010 and integrated with IERREWS) • Structural Monitoring Arrays - Fatih Sultan Mehmet Suspension Bridge (1200m-long suspension bridge across the Bosphorus, five 3-component accelerometers + GPS sensors) - Hagia Sophia Array (1500-year-old historical edifice, 9 accelerometers) - Süleymaniye Mosque Array (450-year-old historical edifice,9 accelerometers) - Fatih Mosque Array (237-year-old historical edifice, 9 accelerometers) - Kanyon Building Array (high-rise office building, 5 accelerometers) - Isbank Tower Array (high-rise office building, 5 accelerometers) - ENRON Array (power generation facility, 4 acelerometers) - Mihrimah Sultan Mosque Array (450-year-old historical edifice,9 accelerometers + tiltmeters, to be installed in 2009) - Sultanahmet Mosque Array, (390-year-old historical edifice, 9 accelerometers + tiltmeters, to be installed in 2009) • Special Arrays - Atakoy Vertical Array (four 3-component accelerometers at 25, 50, 75, and 150 m depths) - Marmara Tube Tunnel (1400 m long submerged tunnel, 128 ch. accelerometric data, 24 ch. strain data, to be installed in 2010) - Air-Force Academy

  20. MIMO Communication for Cellular Networks

    CERN Document Server

    Huang, Howard; Venkatesan, Sivarama

    2012-01-01

    As the theoretical foundations of multiple-antenna techniques evolve and as these multiple-input multiple-output (MIMO) techniques become essential for providing high data rates in wireless systems, there is a growing need to understand the performance limits of MIMO in practical networks. To address this need, MIMO Communication for Cellular Networks presents a systematic description of MIMO technology classes and a framework for MIMO system design that takes into account the essential physical-layer features of practical cellular networks. In contrast to works that focus on the theoretical performance of abstract MIMO channels, MIMO Communication for Cellular Networks emphasizes the practical performance of realistic MIMO systems. A unified set of system simulation results highlights relative performance gains of different MIMO techniques and provides insights into how best to use multiple antennas in cellular networks under various conditions. MIMO Communication for Cellular Networks describes single-user,...

  1. Percolation properties of complex networks with weak and strong clustering

    Science.gov (United States)

    Serrano, M. Angeles

    2007-03-01

    A diversity of systems in the real world can be analyzed as complex networks. This makes any theoretical development in the field potentially applicable to many different areas. As a germane example, percolation has helped us to understand, for instance, the high resilience of scale-free networks in front of the random removal of a fraction of their constituents, with important implications for communication or biological systems among others. In addition to its high theoretical interest, it serves as a conceptual approach to treat more factual problems on networks, such as the dynamics of epidemic spreading. On the other hand, when large systems of interactions are mapped into comprehensible graphs, just vertices and edges are usually recognized as the primary building blocks. However, transitive relations, represented by triangles and referred to as clustering, should also be taken into account as a basic structure whose presence and self-organization can drastically impact network structure and properties. In this framework, the introduction of clustering in the percolation analysis of complex networks represents a theoretical challenge. Previous approaches were based on the idea of branching process, which works well when the network is locally treelike and thus the clustering coefficient is very small. Real networks, however, are shown to have a significant level of clustering. They can be classified in networks with weak transitivity, in which triangles are disjoint, and networks with strong transitivity, where edges are forced to share many triangles. The class a network belongs to changes its percolation properties. For networks with weak clustering, we find analytically the critical point for the onset of the giant component and its size. By means of numerical simulations, we also prove that, when comparing with the unclustered counterpart, weak clustering hinders the onset of the giant connected component whereas it is favored by strong clustering. This

  2. Emerging trends in communication networks

    CERN Document Server

    Hasan, Syed Faraz

    2014-01-01

    This book covers the state of the art in communication networks with the help of illustrative diagrams and recent references published in reputed journals and magazines. The book gives readers a glimpse into the next generation of communication networks. It explores topics that are currently in the research phase and/or are expected to be deployed in recent future such as LTE networks and IPv6 networks. This book is written for students/researchers who wish to come up to date with the recent trends in telecommunications.

  3. EPA Library Network Communication Strategies

    Science.gov (United States)

    To establish Agency-wide procedures for the EPA National Library Network libraries to communicate, using a range of established mechanisms, with other EPA libraries, EPA staff, organizations and the public.

  4. Networked Constellation Communications Technologies

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop communications architectures and enabling technologies for mission concepts relying on multiple spatially distributed spacecraft to perform coordinated...

  5. Bodrum Strong Motion Network, Mugla, Turkey

    Science.gov (United States)

    Alcik, H. A.; Tanircan, G.; Korkmaz, A.

    2015-12-01

    The Gulf of Gökova is located in southwestern Turkey near the Aegean Sea and surrounded by Datça Peninsula to the south, the island of Kos to the west and Bodrum Peninsula to the north. The Bodrum peninsula with a population of one million in summer season is one of the most populated touristic centers of Turkey. This region is also surrounded by numerous active seismic entities such as Ula-Ören Fault Zone, Gökova Graben etc.. and demonstrates high seismic hazard. In the past, many destructive earthquakes have occurred in southwestern Turkey. One of the destructive historical earthquakes is 1493 Kos event (Mw=6.9) caused heavy damage in Bodrum. In the instrumental period seismic activity in the Gökova region includes the Ms>6.0 earthquakes of 23 April 1933 (Ms=6.4), 23 May 1941 (Ms=6.0), 13 December 1941 (Ms=6.5) events. Intense earthquake activity (Mw5+) occurred in Gulf of Gökova in August 2004 and January 2005. Considering the high seismicity and population of this region, a strong ground motion monitoring system stationed in dense settlements in the Bodrum Peninsula: Bodrum, Turgutreis, Yalıkavak, Çiftlik and Ortakent was deployed on June 2015. The network consists of 5 strong motion recorders, has been set up with the aim of monitoring of regional earthquakes, collecting accurate and reliable data for engineering and scientific research purposes, in particular to provide input for future earthquake rapid reporting and early warning implementation projects on urban environments in the Bodrum peninsula and the surrounding areas. In this poster presentation, we briefly introduce the Bodrum Network and discuss our future plans for further developments.

  6. BRAND COMMUNICATION ON SOCIAL NETWORKS

    Directory of Open Access Journals (Sweden)

    Otilia-Elena PLATON

    2015-07-01

    Full Text Available The communication represents a basic element for the marketing activity that helps companies to achieve their objectives. Building long-term relationships between brands and consumers is one of the most important objectives pursued by marketers. This involves brand communication and creating multiple connections with consumers, even in the online environment. From this point of view, social networks proved to be an effective way of linking brands and consumers online. This paper aims to present some aspects involved by the usage of social networks in brand communication by analyzing several examples of online marketing campaigns implemented on Facebook on the occasion of Valentine's Day by six different brands.

  7. Fourth international conference on Networks & Communications

    CERN Document Server

    Meghanathan, Natarajan; Nagamalai, Dhinaharan; Computer Networks & Communications (NetCom)

    2013-01-01

    Computer Networks & Communications (NetCom) is the proceedings from the Fourth International Conference on Networks & Communications. This book covers theory, methodology and applications of computer networks, network protocols and wireless networks, data communication technologies, and network security. The proceedings will feature peer-reviewed papers that illustrate research results, projects, surveys and industrial experiences that describe significant advances in the diverse areas of computer networks & communications.

  8. Communicating embedded systems networks applications

    CERN Document Server

    Krief, Francine

    2013-01-01

    Embedded systems become more and more complex and require having some knowledge in various disciplines such as electronics, data processing, telecommunications and networks. Without detailing all the aspects related to the design of embedded systems, this book, which was written by specialists in electronics, data processing and telecommunications and networks, gives an interesting point of view of communication techniques and problems in embedded systems. This choice is easily justified by the fact that embedded systems are today massively communicating and that telecommunications and network

  9. BRAND COMMUNICATION ON SOCIAL NETWORKS

    OpenAIRE

    Otilia-Elena PLATON

    2015-01-01

    The communication represents a basic element for the marketing activity that helps companies to achieve their objectives. Building long-term relationships between brands and consumers is one of the most important objectives pursued by marketers. This involves brand communication and creating multiple connections with consumers, even in the online environment. From this point of view, social networks proved to be an effective way of linking brands and consumers online. This paper aims to prese...

  10. Underwater optical wireless communication network

    Science.gov (United States)

    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.

  11. Fifth International Conference on Networks & Communications

    CERN Document Server

    Nagamalai, Dhinaharan; Rajasekaran, Sanguthevar

    2014-01-01

    This book covers theory, methodology and applications of computer networks, network protocols and wireless networks, data communication technologies, and network security. The book is based on the proceedings from the Fifth International Conference on Networks & Communications (NetCom). The proceedings will feature peer-reviewed papers that illustrate research results, projects, surveys and industrial experiences that describe significant advances in the diverse areas of computer networks & communications.

  12. Communication Policies in Knowledge Networks

    Science.gov (United States)

    Ioannidis, Evangelos; Varsakelis, Nikos; Antoniou, Ioannis

    2018-02-01

    Faster knowledge attainment within organizations leads to improved innovation, and therefore competitive advantage. Interventions on the organizational network may be risky or costly or time-demanding. We investigate several communication policies in knowledge networks, which reduce the knowledge attainment time without interventions. We examine the resulting knowledge dynamics for real organizational networks, as well as for artificial networks. More specifically, we investigate the dependence of knowledge dynamics on: (1) the Selection Rule of agents for knowledge acquisition, and (2) the Order of implementation of "Selection" and "Filtering". Significant decrease of the knowledge attainment time (up to -74%) can be achieved by: (1) selecting agents of both high knowledge level and high knowledge transfer efficiency, and (2) implementing "Selection" after "Filtering" in contrast to the converse, implicitly assumed, conventional prioritization. The Non-Commutativity of "Selection" and "Filtering", reveals a Non-Boolean Logic of the Network Operations. The results demonstrate that significant improvement of knowledge dynamics can be achieved by implementing "fruitful" communication policies, by raising the awareness of agents, without any intervention on the network structure.

  13. Using networking and communications software in business

    CERN Document Server

    McBride, PK

    2014-01-01

    Using Networking and Communications Software in Business covers the importance of networks in a business firm, the benefits of computer communications within a firm, and the cost-benefit in putting up networks in businesses. The book is divided into six parts. Part I looks into the nature and varieties of networks, networking standards, and network software. Part II discusses the planning of a networked system, which includes analyzing the requirements for the network system, the hardware for the network, and network management. The installation of the network system and the network managemen

  14. Communications in interference limited networks

    CERN Document Server

    2016-01-01

    This book offers means to handle interference as a central problem of operating wireless networks. It investigates centralized and decentralized methods to avoid and handle interference as well as approaches that resolve interference constructively. The latter type of approach tries to solve the joint detection and estimation problem of several data streams that share a common medium. In fact, an exciting insight into the operation of networks is that it may be beneficial, in terms of an overall throughput, to actively create and manage interference. Thus, when handled properly, "mixing" of data in networks becomes a useful tool of operation rather than the nuisance as which it has been treated traditionally. With the development of mobile, robust, ubiquitous, reliable and instantaneous communication being a driving and enabling factor of an information centric economy, the understanding, mitigation and exploitation of interference in networks must be seen as a centrally important task.

  15. Information communication on complex networks

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  17. A Novel Frequency Communication Technology in Power Distribution Communication Network

    Directory of Open Access Journals (Sweden)

    Li Ying-Jun

    2017-01-01

    Full Text Available With the expansion of the power terminal access network scale, the main road corridor resources, branch line cable Laying difficulties has become an important factor restricting the construction of the network. In this paper, we focus on the frequency communication technology in power distribution communication network, and design a novel technology in communication mode, error correcting coding and data transfer frame format. We also discuss the influence of voltage phase difference on power frequency communication. Meanwhile, we present the application scenario Electricity information collection, electricity remote control and other power business in smart grid with the novel frequency communication technology.

  18. The Structure of Online Consumer Communication Networks

    NARCIS (Netherlands)

    B.G.C. Dellaert (Benedict); M.J.W. Harmsen-van Hout (Marjolein); P.J.J. Herings (Jean-Jacques)

    2006-01-01

    textabstractIn this paper we study the structure of the bilateral communication links within Online Consumer Communication Networks (OCCNs), such as virtual communities. Compared to the offline world, consumers in online networks are highly flexible to choose their communication partners and little

  19. Agricultural informational flow in informal communication networks ...

    African Journals Online (AJOL)

    Despite the rapid growth in the use of modern communication media to improve access to agricultural information, local information networks remain an important means of communication among rural folk. This study examined informal communication networks of rural farmers in the Ahafo Ano south district of Ghana to ...

  20. Critical size of ego communication networks

    Science.gov (United States)

    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).

  1. Ad-hoc networking towards seamless communications

    CERN Document Server

    Gavrilovska, Liljana

    2006-01-01

    Ad-Hoc Networking Towards Seamless Communications is dedicated to an area that attracts growing interest in academia and industry and concentrates on wireless ad hoc networking paradigm. The persistent efforts to acquire the ability to establish dynamic wireless connections from anywhere to anyone with any device without prerequisite imbedded infrastructure move the communications boundaries towards ad-hoc networks. Recently, ad hoc networking has attracted growing interest due to advances in wireless communications, and developed framework for running IP based protocols. The expected degree of penetration of these networks will depend on the successful resolution of the key features. Ad-hoc networks pose many complex and open problems for researchers. Ad-Hoc Networking Towards Seamless Communications reveals the state-of-the-art in wireless ad-hoc networking and discusses some of the key research topics that are expected to promote and accelerate the commercial applications of these networks (e.g., MAC, rout...

  2. Wireless communications networks for the smart grid

    CERN Document Server

    Ho, Quang-Dung; Rajalingham, Gowdemy; Le-Ngoc, Tho

    2014-01-01

    This brief presents a comprehensive review of the network architecture and communication technologies of the smart grid communication network (SGCN). It then studies the strengths, weaknesses and applications of two promising wireless mesh routing protocols that could be used to implement the SGCN. Packet transmission reliability, latency and robustness of these two protocols are evaluated and compared by simulations in various practical SGCN scenarios. Finally, technical challenges and open research opportunities of the SGCN are addressed. Wireless Communications Networks for Smart Grid provi

  3. Maritime wideband communication networks video transmission scheduling

    CERN Document Server

    Yang, Tingting

    2014-01-01

    This Springer Brief covers emerging maritime wideband communication networks and how they facilitate applications such as maritime distress, urgency, safety and general communications. It provides valuable insight on the data transmission scheduling and protocol design for the maritime wideband network. This brief begins with an introduction to maritime wideband communication networks including the architecture, framework, operations and a comprehensive survey on current developments. The second part of the brief presents the resource allocation and scheduling for video packet transmission wit

  4. societal impact of electronic communication networks

    OpenAIRE

    Gremont, Boris

    2012-01-01

    The talk provides an overview of the present and future of electronic communication networks. Starting from the creation of the computer, key concepts pertaining to the scientific and technological development of electronic communication networks will be introduced and discussed in terms of their positive and sustained impact for society. Current trends and shortcomings will also be discussed. With the increasing reliance of future societies on communication networks, the need for improved sy...

  5. Social networks: communication and change

    Directory of Open Access Journals (Sweden)

    Gustavo Cardoso

    2011-01-01

    Full Text Available Virtual social networks have brought about the possibility for open and plural debate, where all those with the necessary literacy skills and means are able to participate in the creation and dissemination of information. By pressing political agents and determining the “agenda” of a lot of the media, users demonstrate that we stand at an ideal platform for creating both real social movements and more or less fleeting events, as manifestos or virtual campaigns. Nonetheless, in order to understand the role of virtual social networks in today’s world, we need to answer some prior questions. Are we facing a new communication model, whereby the product of “disinterested” interactivity creates an aura of confidence in disseminated information, often quite higher that that seen in the “old media”? Will that interactivity be a chance to fight-off citizens’ growing detachment with regard to the “res publica”? Will we find in citizen-made journalism, transmitted through virtual social networks, the consecration of a true fourth power? On the other hand, can we call the distinct collective movements we have seen emerging true “social movements”?The present article aims to examine this and other issues that come to the fore in the intricate social world of cyberspace.

  6. Social network analysis and dual rover communications

    Science.gov (United States)

    Litaker, Harry L.; Howard, Robert L.

    2013-10-01

    Social network analysis (SNA) refers to the collection of techniques, tools, and methods used in sociometry aiming at the analysis of social networks to investigate decision making, group communication, and the distribution of information. Human factors engineers at the National Aeronautics and Space Administration (NASA) conducted a social network analysis on communication data collected during a 14-day field study operating a dual rover exploration mission to better understand the relationships between certain network groups such as ground control, flight teams, and planetary science. The analysis identified two communication network structures for the continuous communication and Twice-a-Day Communication scenarios as a split network and negotiated network respectfully. The major nodes or groups for the networks' architecture, transmittal status, and information were identified using graphical network mapping, quantitative analysis of subjective impressions, and quantified statistical analysis using Sociometric Statue and Centrality. Post-questionnaire analysis along with interviews revealed advantages and disadvantages of each network structure with team members identifying the need for a more stable continuous communication network, improved robustness of voice loops, and better systems training/capabilities for scientific imagery data and operational data during Twice-a-Day Communications.

  7. Communication and control for networked complex systems

    CERN Document Server

    Peng, Chen; Han, Qing-Long

    2015-01-01

    This book reports on the latest advances in the study of Networked Control Systems (NCSs). It highlights novel research concepts on NCSs; the analysis and synthesis of NCSs with special attention to their networked character; self- and event-triggered communication schemes for conserving limited network resources; and communication and control co-design for improving the efficiency of NCSs. The book will be of interest to university researchers, control and network engineers, and graduate students in the control engineering, communication and network sciences interested in learning the core principles, methods, algorithms and applications of NCSs.

  8. The physics of communicability in complex networks

    International Nuclear Information System (INIS)

    Estrada, Ernesto; Hatano, Naomichi; Benzi, Michele

    2012-01-01

    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.

  9. Distributed wireless quantum communication networks

    International Nuclear Information System (INIS)

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

    2013-01-01

    The distributed wireless quantum communication network (DWQCN) has a distributed network topology and transmits information by quantum states. In this paper, we present the concept of the DWQCN and propose a system scheme to transfer quantum states in the DWQCN. The system scheme for transmitting information between any two nodes in the DWQCN includes a routing protocol and a scheme for transferring quantum states. The routing protocol is on-demand and the routing metric is selected based on the number of entangled particle pairs. After setting up a route, quantum teleportation and entanglement swapping are used for transferring quantum states. Entanglement swapping is achieved along with the process of routing set up and the acknowledgment packet transmission. The measurement results of each entanglement swapping are piggybacked with route reply packets or acknowledgment packets. After entanglement swapping, a direct quantum link between source and destination is set up and quantum states are transferred by quantum teleportation. Adopting this scheme, the measurement results of entanglement swapping do not need to be transmitted specially, which decreases the wireless transmission cost and transmission delay. (general)

  10. Intercultural Communication in Online Social Networking Discourse

    Science.gov (United States)

    Chen, Hsin-I

    2017-01-01

    This article presents a case study that examines how an online social networking community is constituted through intercultural discourse on the part of one learner sojourning in the US. Using Byram's model of intercultural communicative competence, this study examines the learner's naturalistic communication in a social networking site (SNS). The…

  11. Collaborative communication protocols for wireless sensor networks

    NARCIS (Netherlands)

    Dulman, S.O.; van Hoesel, L.F.W.; Nieberg, T.; Havinga, Paul J.M.

    In this document, the design of communication within a wireless sensor network is discussed. The resource limitations of such a network, especially in terms of energy, require an integrated approach for all (traditional) layers of communication. We present such an integrated, collaborative approach

  12. Real-Time Communication Networks Onboard Ships

    DEFF Research Database (Denmark)

    Nielsen, Jens Frederik Dalsgaard; Nielsen, Kirsten Mølgaard; Jørgensen, N.

    1995-01-01

    This paper describes the ATOMOS communication network project carried out within the EU project ATOMOS, to be used for ISC purposes.......This paper describes the ATOMOS communication network project carried out within the EU project ATOMOS, to be used for ISC purposes....

  13. Network Communication for Low Level RF Control

    International Nuclear Information System (INIS)

    Liu Weiqing; Yin Chengke; Zhang Tongxuan; Fu Zechuan; Liu Jianfei

    2009-01-01

    Low Level RF (LLRF) control system for storage ring of Shanghai Synchrotron Radiation Facility (SSRF) has been built by digital technology. The settings of parameters and the feedback loop status are carried out through the network communication interface, and the local oscillation and clock, which is the important component of the digital LLRF control system, are also configured through network communication. NIOS II processor was employed as a core to build the embedded system with a real-time operating system MicroC/OS-II, finally Lightweight TCP/IP (LwIP) was used to achieve the communication interface. The communication network is stable after a long-term operation. (authors)

  14. Effective Protocols for Mobile Communications and Networking

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. Communication and Networking in Smart Grids

    CERN Document Server

    Xiao, Yang

    2012-01-01

    Appropriate for researchers, practitioners, and students alike, Communication and Networking in Smart Grids presents state-of-the-art approaches and novel technologies for communication networks in smart grids. It explains how contemporary grid networks are developed and deployed and presents a collection of cutting-edge advances to help improve current practice. Prominent researchers working on smart grids and in related fields around the world explain the fundamental aspects and applications of smart grids. Describing the role that communication and networking will play in future smart grids

  16. Corporate Communication in the Network Economy

    DEFF Research Database (Denmark)

    Foss, Nicolai Juul; Kristensen, Tore; Wilke, Ricky

    This paper draws on ideas in economics and game theory to develop a new theory of marketing and corporate communication in the emerging network economy. We argue that in a network economy, firms and consumers will confront `coordination problems.' With the emerging network economy all this become...... a simple game theoretic model to explain this, and discuss marketing applications and possible strategies.Key wordsCoordination problems, common knowledge, corporate communication...

  17. French network and acquired experience on record strong ground motion

    International Nuclear Information System (INIS)

    Ferrieux, H.; Mohammadioun, G.

    1988-03-01

    The network intended to record strong ground motion in continental France is composed for the most part of instrument packages incorporated into nuclear installations, which are supplemented by a certain number of accelerometers placed in the most highly seismic areas. In a country where the level of seismicity is relatively modest, such a network is not conductive to the acquisition of new data, which, instead, is obtained through spot studies of limited duration using more sensitive instruments or through the recording of strong ground motion in neighbouring countries [fr

  18. Communication on the structure of biological networks

    Indian Academy of Sciences (India)

    Networks are widely used to represent interaction pattern among the components in complex systems. Structures of real networks from different domains may vary quite significantly. As there is an interplay between network architecture and dynamics, structure plays an important role in communication and spreading of ...

  19. Corporate Communication in the Network Economy

    DEFF Research Database (Denmark)

    Foss, Nicolai Juul; Kristensen, Tore; Wilke, Ricky

    This paper draws on ideas in economics and game theory to develop a new theory of marketing and corporate communication in the emerging network economy. We argue that in a network economy, firms and consumers will confront `coordination problems.' With the emerging network economy all this become...... a simple game theoretic model to explain this, and discuss marketing applications and possible strategies.Key wordsCoordination problems, common knowledge, corporate communication......This paper draws on ideas in economics and game theory to develop a new theory of marketing and corporate communication in the emerging network economy. We argue that in a network economy, firms and consumers will confront `coordination problems.' With the emerging network economy all this become...

  20. The handbook of optical communication networks

    CERN Document Server

    Ilyas, Mohammad

    2003-01-01

    The Handbook of Optical Communication Networks presents comprehensive, up-to-date technical information on integrated, state-of-the-art optical networks. Beginning with an in-depth intoduction to the field, top international authorities explore every major aspect of optical networks, from basic concepts to research grade material. Their discussions cover all of the essential topics, including protocols, resource management, routing and wavelength assignment in WDM networks, connection management, survivability, enabling technologies, and future trends.

  1. Location of terminals in a communications network

    DEFF Research Database (Denmark)

    2015-01-01

    A method (400, 500) of identifying nodes in a communications network is disclosed, the nodes being for use in locating wireless terminals within the network based upon reports from the wireless terminals of transmissions received from the nodes. The method (400, 500) comprises prioritising......, a reference node. Also disclosed is a method (100, 200) for locating a plurality of wireless terminals in a communications network, the network comprising a plurality of network nodes at known locations, wherein the nodes emit wireless transmissions in an unsynchronised manner, such that a time difference...... exists between the emission time of corresponding transmissions from different nodes. The method comprises receiving reports from a plurality of wireless terminals of transmissions received from the network nodes (110, 210), selecting a subset of network nodes (120, 220) and identifying a plurality...

  2. Future networks and technologies supporting innovative communications

    DEFF Research Database (Denmark)

    Prasad, Ramjee

    2012-01-01

    and applications. This paper focuses on the technological aspects of ubiquitous networking and communication technologies, including challenges related to green communications, and security, privacy and trust. The paper proposes a novel concept for a Wireless Innovative System for Dynamically Operating Mega...

  3. Communications and Cooperation in Public Network Situations

    NARCIS (Netherlands)

    Suijs, J.P.M.; Borm, P.E.M.; Hamers, H.J.M.; Koster, M.A.L.; Quant, M.

    2001-01-01

    This paper focuses on sharing the costs and revenues of maintaining a public network communication structure.Revenues are assumed to be bilateral and communication links are publicly available but costly.It is assumed that agents are located at the vertices of an undirected graph in which the edges

  4. Communication on the structure of biological networks

    Indian Academy of Sciences (India)

    As there is an interplay between network architecture and dynamics, structure plays an important role in communication and spreading of information in a network. ... Department of Mathematics and Statistics, Indian Institute of Science Education and Research Kolkata, Mohanpur 741 246, India; Department of Biological ...

  5. Communicating and Networking by Astronomy Librarians

    Science.gov (United States)

    Cummins, Marlene; Grothkopf, Uta

    Librarians in other disciplines have often marveled at the effective networking that takes place among astronomy librarians. How do we do it? In January 2001, an international survey was undertaken to assess problems, successes and trends around the world. We summarize the results as described in our publication ``Communicating and Networking in Astronomy Libraries'' (Grothkopf & Cummins 2001).

  6. Information and Communication Network Among Natural Scientists ...

    African Journals Online (AJOL)

    This study tries to find out the extent of information and communication networks among natural scientists in Ahmadu Bello University, Zaria. Their ways of information sharing, and the extent of their participation in information networking were investigated. Using two (2) research questions, data was collected from 299 pure ...

  7. 2007 Information and Communication Network Among Natural ...

    African Journals Online (AJOL)

    ezra

    This study tries to find out the extent of information and communication networks among natural scientists in. Ahmadu Bello University, Zaria. Their ways of information sharing, and the extent of their participation in information networking were investigated. Using two (2) research questions, data was collected from 299 pure.

  8. Communication, knowledge, social network and family planning ...

    African Journals Online (AJOL)

    Communication, knowledge, social network and family planning utilization among couples in Mwanza, Tanzania. IH Mosha, R Ruben. Abstract. Family planning utilization in Tanzania is low. This study was cross sectional. It examined family planning use and socio demographic variables, social networks, knowledge and ...

  9. Stress Testing of Data-Communication Networks

    Science.gov (United States)

    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

  10. Computer networks and advanced communications

    International Nuclear Information System (INIS)

    Koederitz, W.L.; Macon, B.S.

    1992-01-01

    One of the major methods for getting the most productivity and benefits from computer usage is networking. However, for those who are contemplating a change from stand-alone computers to a network system, the investigation of actual networks in use presents a paradox: network systems can be highly productive and beneficial; at the same time, these networks can create many complex, frustrating problems. The issue becomes a question of whether the benefits of networking are worth the extra effort and cost. In response to this issue, the authors review in this paper the implementation and management of an actual network in the LSU Petroleum Engineering Department. The network, which has been in operation for four years, is large and diverse (50 computers, 2 sites, PC's, UNIX RISC workstations, etc.). The benefits, costs, and method of operation of this network will be described, and an effort will be made to objectively weigh these elements from the point of view of the average computer user

  11. Evolutionary dynamics of complex communications networks

    CERN Document Server

    Karyotis, Vasileios; Papavassiliou, Symeon

    2013-01-01

    Until recently, most network design techniques employed a bottom-up approach with lower protocol layer mechanisms affecting the development of higher ones. This approach, however, has not yielded fascinating results in the case of wireless distributed networks. Addressing the emerging aspects of modern network analysis and design, Evolutionary Dynamics of Complex Communications Networks introduces and develops a top-bottom approach where elements of the higher layer can be exploited in modifying the lowest physical topology-closing the network design loop in an evolutionary fashion similar to

  12. A Quantum Cryptography Communication Network Based on Software Defined Network

    Directory of Open Access Journals (Sweden)

    Zhang Hongliang

    2018-01-01

    Full Text Available With the development of the Internet, information security has attracted great attention in today’s society, and quantum cryptography communication network based on quantum key distribution (QKD is a very important part of this field, since the quantum key distribution combined with one-time-pad encryption scheme can guarantee the unconditional security of the information. The secret key generated by quantum key distribution protocols is a very valuable resource, so making full use of key resources is particularly important. Software definition network (SDN is a new type of network architecture, and it separates the control plane and the data plane of network devices through OpenFlow technology, thus it realizes the flexible control of the network resources. In this paper, a quantum cryptography communication network model based on SDN is proposed to realize the flexible control of quantum key resources in the whole cryptography communication network. Moreover, we propose a routing algorithm which takes into account both the hops and the end-to-end availible keys, so that the secret key generated by QKD can be used effectively. We also simulate this quantum cryptography communication network, and the result shows that based on SDN and the proposed routing algorithm the performance of this network is improved since the effective use of the quantum key resources.

  13. Scalable Optical-Fiber Communication Networks

    Science.gov (United States)

    Chow, Edward T.; Peterson, John C.

    1993-01-01

    Scalable arbitrary fiber extension network (SAFEnet) is conceptual fiber-optic communication network passing digital signals among variety of computers and input/output devices at rates from 200 Mb/s to more than 100 Gb/s. Intended for use with very-high-speed computers and other data-processing and communication systems in which message-passing delays must be kept short. Inherent flexibility makes it possible to match performance of network to computers by optimizing configuration of interconnections. In addition, interconnections made redundant to provide tolerance to faults.

  14. Challenges of Integrating NASA's Space Communications Networks

    Science.gov (United States)

    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

  15. Challenges of Integrating NASAs Space Communication Networks

    Science.gov (United States)

    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

  16. Integration of strong motion networks and accelerometric data in Europe

    Science.gov (United States)

    Luzi, L.; Clinton, J. F.; Akkar, S.; Sleeman, R.; Van Eck, T.

    2014-12-01

    Efforts for an organized collection of strong motion data in Europe started during the Fourth Framework Program granted by the European Union, with the first release of the European Strong Motion database. Subsequently other attempts were made, but the initiatives were carried out within a project by a single or few institutions, often isolated from data providers. During the Seventh Framework Program, in the context of the project NERA, parallel to the establishment of infrastructures, major efforts were devoted on the improvement of networking among strong-motion data providers in the broader European countries. Two major infrastructures for storing and disseminating accelerometric data and metadata were built: a. The Rapid-Raw Strong Motion (RRSM) database that automatically delivers strong motion products in near-real time. The system collects and uses all relevant, unrestricted waveform data from the European Integrated waveform Data Archive (EIDA) within minutes after an earthquake (M>=3.5) in the European- Mediterranean region. The RRSM web interface is available at http://orfeusdev.knmi.nl:8080/opencms/rrsm b. A prototype of strong-motion database (Engineering Strong Motion database, ESM) that contains an initial core formed by the accelerograms recorded by Italian and Turkish strong-motion data providers. ESM is structured to contain not only the data available in EIDA but also off-line data; earthquake and strong-motion metadata contain more detailed information than the corresponding metadata in RRSM. A Working Group (WG5 - acceleration and strong motion data), operating under ORFEUS, has been created to build the basis for the sustainable integrated pan-European accelerometric data distribution. The responsibilities and duties of the WG5 are envisaged as follows: 1. Setting rules for data dissemination; 2. Establishing MoU's with data providers; 3. Collaborating with the European project EPOS for the preparation of projects; 4. Contacting similar

  17. BAKNET - Communication network for radiation monitoring devices

    International Nuclear Information System (INIS)

    Cohen, Y.; Wengrowicz, U.; Tirosh, D.; Barak, D.

    1997-01-01

    A system, based on a new concept of controlling and monitoring distributed radiation monitors, has been developed and approved at the NRCN. The system, named B AKNET Network , consists of a series of communication adapters connected to a main PC via an RS-485 communication network (see Fig. 1). The network's maximal length is 1200 meters and it enables connection of up to 128 adapters. The BAKNET adapters are designed to interface output signals of different types of stationary radiation monitors to a main PC. The BAKNET adapters' interface type includes: digital, analog, RS-232, and mixed output signals. This allows versatile interfacing of different stationary radiation monitors to the main computer. The connection to the main computer is via an RS-485 network, utilizing an identical communication protocol. The PC software, written in C ++ under MS-Windows, consists of two main programs. The first is the data collection program and the second is the Human Machine Interface (HMI). (authors)

  18. Ising models of strongly coupled biological networks with multivariate interactions

    Science.gov (United States)

    Merchan, Lina; Nemenman, Ilya

    2013-03-01

    Biological networks consist of a large number of variables that can be coupled by complex multivariate interactions. However, several neuroscience and cell biology experiments have reported that observed statistics of network states can be approximated surprisingly well by maximum entropy models that constrain correlations only within pairs of variables. We would like to verify if this reduction in complexity results from intricacies of biological organization, or if it is a more general attribute of these networks. We generate random networks with p-spin (p > 2) interactions, with N spins and M interaction terms. The probability distribution of the network states is then calculated and approximated with a maximum entropy model based on constraining pairwise spin correlations. Depending on the M/N ratio and the strength of the interaction terms, we observe a transition where the pairwise approximation is very good to a region where it fails. This resembles the sat-unsat transition in constraint satisfaction problems. We argue that the pairwise model works when the number of highly probable states is small. We argue that many biological systems must operate in a strongly constrained regime, and hence we expect the pairwise approximation to be accurate for a wide class of problems. This research has been partially supported by the James S McDonnell Foundation grant No.220020321.

  19. <strong>Polyrhythmic communicational devices appear as languagein the brains of musiciansstrong>

    DEFF Research Database (Denmark)

    Vuust, Peter; Østergaard, Leif; Roepstorff, Andreas

    2006-01-01

    a unique setting to evaluate communicational aspectsof music practices that rarely enters the present discourseon the subject. We employ Miles Davis' quintet of the1960es and its use of polyrhythmic structures as a generalexample of a jazz group focusing on communication. First,we consider jazz......The relationship between music and language has been oneof the most fiercely debated subjects in the modern literatureof neuroscience and music. In this paper we argue thata musicological study of the online communication betweenjazz musicians in combination with brain imaging studiesoffers...

  20. Communication cliques in mobile phone calling networks

    Science.gov (United States)

    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.

  1. Case studies of attacks on communication networks

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Sin Bok; Han, Eon Suk [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1996-06-15

    Recently, as the computer hardware and communications are developed, the data exchange through inter-networking has been highlighted and the data is being recognized as a great asset. Most of the organizations, businesses and enterprises are open to the external world-computer communication networks, attention must be focused on the securities of the information infrastructure. A government organization has been developing 'Circuits Analyzers', and 'Hacker-Tracking Program' and is struggling to track down sneakers. In this report, we analyze the contents of the cases where the communication network has been invaded, from the past up until now in Korea. This report also contains the result of a study on E-mail security, for the protection of KAERI Integrated Management Information System under which utilizes the CALS concepts and web services. (Author)

  2. The NASA Space Communications Data Networking Architecture

    Science.gov (United States)

    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.

  3. Deep convolutional neural networks as strong gravitational lens detectors

    Science.gov (United States)

    Schaefer, C.; Geiger, M.; Kuntzer, T.; Kneib, J.-P.

    2018-03-01

    Context. Future large-scale surveys with high-resolution imaging will provide us with approximately 105 new strong galaxy-scale lenses. These strong-lensing systems will be contained in large data amounts, however, which are beyond the capacity of human experts to visually classify in an unbiased way. Aim. We present a new strong gravitational lens finder based on convolutional neural networks (CNNs). The method was applied to the strong-lensing challenge organized by the Bologna Lens Factory. It achieved first and third place, respectively, on the space-based data set and the ground-based data set. The goal was to find a fully automated lens finder for ground-based and space-based surveys that minimizes human inspection. Methods: We compared the results of our CNN architecture and three new variations ("invariant" "views" and "residual") on the simulated data of the challenge. Each method was trained separately five times on 17 000 simulated images, cross-validated using 3000 images, and then applied to a test set with 100 000 images. We used two different metrics for evaluation, the area under the receiver operating characteristic curve (AUC) score, and the recall with no false positive (Recall0FP). Results: For ground-based data, our best method achieved an AUC score of 0.977 and a Recall0FP of 0.50. For space-based data, our best method achieved an AUC score of 0.940 and a Recall0FP of 0.32. Adding dihedral invariance to the CNN architecture diminished the overall score on space-based data, but achieved a higher no-contamination recall. We found that using committees of five CNNs produced the best recall at zero contamination and consistently scored better AUC than a single CNN. Conclusions: We found that for every variation of our CNN lensfinder, we achieved AUC scores close to 1 within 6%. A deeper network did not outperform simpler CNN models either. This indicates that more complex networks are not needed to model the simulated lenses. To verify this, more

  4. Green networking and communications ICT for sustainability

    CERN Document Server

    Khan, Shafiullah

    2013-01-01

    Although the information and communication technology (ICT) industry accounted for only 2 percent of global greenhouse gas emissions in 2007, the explosive increase in data traffic brought about by a rapidly growing user base of more than a billion wireless subscribers is expected to nearly double that number by 2020. It is clear that now is the time to rethink how we design and build our networks.Green Networking and Communications: ICT for Sustainability brings together leading academic and industrial researchers from around the world to discuss emerging developments in energy-efficient netw

  5. An underwater optical wireless communication network

    Science.gov (United States)

    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.

  6. Content Delivery in Future Mobile Communication Networks

    Science.gov (United States)

    Jonas, Karl; Raber, Sergey

    2003-07-01

    With the fast progress in the deployment of wireless networks during the last few years, the global communication market requires the development of new methods for content delivery towards mobile users. It is currently characterised by the introduction of the 3rd generation of terrestrial mobile networks based on 3GPP's UMTS standard. It is expected that this will eventually lead to integrated all-IP-based infrastructures supporting a variety of radio access technologies (so-called beyond-3G-networks or 4th Generation networks). The integration of mobility support, security and accounting and provisioning of differentiated qualities of service are among the issues which are currently researched in the 4G framework.Since it is not possible to change network protocols and infrastructure at once in order to optimize them for mobile services, it is very important to find an appropriate way for the migration from the current infrastructure towards an integrated architecture, where fixed and mobile networks coexist and interoperate in the most effective and flexible way.The integration of satellite communication networks into the terrestrial mobile communication environment is the focus of R&D activities at the Competence Centre for Advanced Satellite Communication of the FhG FOKUS institute. These activities are presented in this article, with a focus on the CoDeSat Content Delivery over Satellite project.In the remainder of this article we first summarize services and service requirements as they are considered in our work. We then discuss the challenges derived from these requirements with respect to current network and protocol architectures. Finally, we describe our approach, and the current status of our prototype implementation.

  7. Interoperable Communications for Hierarchical Heterogeneous Wireless Networks

    Science.gov (United States)

    2016-04-01

    jammers in multihop cognitive radio networks, 2013 International Conference on Computing , Networking and Communications (ICNC). 27-JAN-13, San...ACCOMPLISHMENTS BY PI: LIJUN QIAN Department of Electrical and Computer Engineering Roy G. Perry College of Engineering Prairie View A&M University... lambda implies stronger noise reduction but at the cost of deblurring accuracy [30]. The first round of TV inpainting is applied spatially on each

  8. Entangled network and quantum communication

    Energy Technology Data Exchange (ETDEWEB)

    Metwally, Nasser, E-mail: Nmetwally@gmail.com [Math. Dept., Faculty of Science, South Valley University, Aswan (Egypt); Math. Dept., College of Science, University of Bahrain, P.O. Box 32038 (Bahrain)

    2011-11-21

    A theoretical scheme is introduced to generate entangled network via Dzyaloshinskii–Moriya (DM) interaction. The dynamics of entanglement between different nodes, which is generated by direct or indirect interaction, is investigated. It is shown that, the direction of (DM) interaction and the locations of the nodes have a sensational effect on the degree of entanglement. The minimum entanglement generated between all the nodes is quantified. The upper and lower bounds of the entanglement depend on the direction of DM interaction, and the repetition of the behavior depends on the strength of DM. The generated entangled nodes are used as quantum channel to perform quantum teleportation, where it is shown that the fidelity of teleporting unknown information between the network members depends on the locations of the members.

  9. Development of IT-based data communication network technology

    International Nuclear Information System (INIS)

    Hong, Seok Boong; Jeong, K. I.; Yoo, Y. R.

    2010-10-01

    - Developing broadband high-reliability real-time communications technology for NPP - Developing reliability and performance validation technology for communications network - Developing security technology for NPP communications network - Developing field communications network for harsh environment of NPP - International standard registration(Oct. 28, 2009, IEC 61500

  10. Green Communications and Networks : Proceedings of the International Conference on Green Communications and Networks

    CERN Document Server

    Ma, Maode

    2012-01-01

    Green Communications and Networks presents 95 papers chosen for publication from among 190 reviewed papers accepted for presentation to the International Conference on Green Communications and Networks (GCN 2011), held in Chongqing, China, July 15-17, 2011. GCN 2011 provided a venue for leading academic and industrial researchers to exchange their views, ideas and research results on innovative technologies and sustainable solutions leading to greener communications and networks. In addition to paper presentations, the conference featured keynote speakers and a panel discussion. Reflecting the broad scope of the conference, the contents are organized in these topical categories: Communication Systems Data Management and Database System Digital Image Processing Education and Informatics Enabling Technologies Forensics, Recognition Technologies and Applications Fuzzy System and Control Graphics and Visualizing Green Computing Internet Growth Modelling and Virtualized Networks Network Components and Application ...

  11. The tactical network operations communication coordinator in mobile UAV networks

    OpenAIRE

    Jeoun, Kristina S.

    2004-01-01

    Approved for public release, distribution is unlimited Warfare planners and tacticians are seeking ways to leverage information technology to gain advantage on the battlefield. With the advent of Internet technologies, complex systems are becoming more networked, and access to information is more critical than ever. The increasing utilization of special operations forces in ad hoc, dynamic operations poses a need for adaptable communications to support the unit. Effective communication wit...

  12. Data communication network at the ASRM facility

    Science.gov (United States)

    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.

  13. Message transfer in a communication network

    Indian Academy of Sciences (India)

    2015-11-27

    Nov 27, 2015 ... We study message transfer in a 2-d communication network of regular nodes and randomly distributed hubs. We study both single message transfer and multiple message transfer on the lattice. The average travel time for single messages travelling between source and target pairs of fixed separations ...

  14. Agricultural information systems and communication networks: the ...

    African Journals Online (AJOL)

    The study examined the Agricultural Information and communication networks among poultry farmers in three (3) area councils of the Federal Capital Territory Abuja, Nigeria. Snow-ball sampling technique was adopted for the study, a total of One hundred and twenty-two (122) respondents were sampled for the study.

  15. Communication network for telemedicine | Debretsion | Zede Journal

    African Journals Online (AJOL)

    Telemedicine is the most promising one for improving the access to specialized health services to all remote, rural areas in all developing countries. Exploiting the technological advancements in the field of electronics, signal processing and software a communication network for telemedicine is proposedfor the existing ...

  16. Protocol for Communication Networking for Formation Flying

    Science.gov (United States)

    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

  17. Strong Horses-Systems Thinking-Strategic Communication

    Science.gov (United States)

    2009-04-30

    need to encounter it in several contexts: Keller and Segel saw emergence in the slime mold assemblages; Jane Jacobs saw it in city neighborhoods...disinformation, to deliver threats 78 Ibid., 16 79 Ibid., 29 30 intended to instill fear ...Blaisdell, 1970), 165. 53 still feared without a strong naval presence in the Pacific the U.S. would not be able to maintain its sphere of

  18. New strong motion network in Georgia: basis for specifying seismic hazard

    Science.gov (United States)

    Kvavadze, N.; Tsereteli, N. S.

    2017-12-01

    Risk created by hazardous natural events is closely related to sustainable development of the society. Global observations have confirmed tendency of growing losses resulting from natural disasters, one of the most dangerous and destructive if which are earthquakes. Georgia is located in seismically active region. So, it is imperative to evaluate probabilistic seismic hazard and seismic risk with proper accuracy. National network of Georgia includes 35 station all of which are seismometers. There are significant gaps in strong motion recordings, which essential for seismic hazard assessment. To gather more accelerometer recordings, we have built a strong motion network distributed on the territory of Georgia. The network includes 6 stations for now, with Basalt 4x datalogger and strong motion sensor Episensor ES-T. For each site, Vs30 and soil resonance frequencies have been measured. Since all but one station (Tabakhmelam near Tbilisi), are located far from power and internet lines special system was created for instrument operation. Solar power is used to supply the system with electricity and GSM/LTE modems for internet access. VPN tunnel was set up using Raspberry pi, for two-way communication with stations. Tabakhmela station is located on grounds of Ionosphere Observatory, TSU and is used as a hub for the network. This location also includes a broadband seismometer and VLF electromagnetic waves observation antenna, for possible earthquake precursor studies. On server, located in Tabakhmela, the continues data is collected from all the stations, for later use. The recordings later will be used in different seismological and engineering problems, namely selecting and creating GMPE model for Caucasus, for probabilistic seismic hazard and seismic risk evaluation. These stations are a start and in the future expansion of strong motion network is planned. Along with this, electromagnetic wave observations will continue and additional antennas will be implemented

  19. Secure Network-Centric Aviation Communication (SNAC)

    Science.gov (United States)

    Nelson, Paul H.; Muha, Mark A.; Sheehe, Charles J.

    2017-01-01

    The existing National Airspace System (NAS) communications capabilities are largely unsecured, are not designed for efficient use of spectrum and collectively are not capable of servicing the future needs of the NAS with the inclusion of new operators in Unmanned Aviation Systems (UAS) or On Demand Mobility (ODM). SNAC will provide a ubiquitous secure, network-based communications architecture that will provide new service capabilities and allow for the migration of current communications to SNAC over time. The necessary change in communication technologies to digital domains will allow for the adoption of security mechanisms, sharing of link technologies, large increase in spectrum utilization, new forms of resilience and redundancy and the possibly of spectrum reuse. SNAC consists of a long term open architectural approach with increasingly capable designs used to steer research and development and enable operating capabilities that run in parallel with current NAS systems.

  20. Data communication network at the ASRM facility

    Science.gov (United States)

    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.

  1. Energy, Entropy and Exergy in Communication Networks

    Directory of Open Access Journals (Sweden)

    Slavisa Aleksic

    2013-10-01

    Full Text Available The information and communication technology (ICT sector is continuously growing, mainly due to the fast penetration of ICT into many areas of business and society. Growth is particularly high in the area of technologies and applications for communication networks, which can be used, among others, to optimize systems and processes. The ubiquitous application of ICT opens new perspectives and emphasizes the importance of understanding the complex interactions between ICT and other sectors. Complex and interacting heterogeneous systems can only properly be addressed by a holistic framework. Thermodynamic theory, and, in particular, the second law of thermodynamics, is a universally applicable tool to analyze flows of energy. Communication systems and their processes can be seen, similar to many other natural processes and systems, as dissipative transformations that level differences in energy density between participating subsystems and their surroundings. This paper shows how to apply thermodynamics to analyze energy flows through communication networks. Application of the second law of thermodynamics in the context of the Carnot heat engine is emphasized. The use of exergy-based lifecycle analysis to assess the sustainability of ICT systems is shown on an example of a radio access network.

  2. Anonymous communication networks protecting privacy on the web

    CERN Document Server

    Peng, Kun

    2014-01-01

    In today's interactive network environment, where various types of organizations are eager to monitor and track Internet use, anonymity is one of the most powerful resources available to counterbalance the threat of unknown spectators and to ensure Internet privacy.Addressing the demand for authoritative information on anonymous Internet usage, Anonymous Communication Networks: Protecting Privacy on the Web examines anonymous communication networks as a solution to Internet privacy concerns. It explains how anonymous communication networks make it possible for participants to communicate with

  3. Local-area communication networks - An overview

    International Nuclear Information System (INIS)

    Kuemmerle, K.

    1982-01-01

    Local-area communication networks represent a new field of activity. In this paper we first describe three scenarios for the use of these networks, and then discuss various technical approaches. Particular emphasis is put on bus and ring systems with various media access control mechanisms. Specifically, we compare the delay-throughput characteristic of two access methods, carrier-sense multiple access with collision detection and token passing, and discuss some significant differences of bus and ring systems concerning wiring, media, transmission, and reliability. (orig.)

  4. Position estimation of transceivers in communication networks

    Science.gov (United States)

    Kent, Claudia A [Pleasanton, CA; Dowla, Farid [Castro Valley, CA

    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.

  5. Capacity analysis of vehicular communication networks

    CERN Document Server

    Lu, Ning

    2013-01-01

    This SpringerBrief focuses on the network capacity analysis of VANETs, a key topic as fundamental guidance on design and deployment of VANETs is very limited. Moreover, unique characteristics of VANETs impose distinguished challenges on such an investigation. This SpringerBrief first introduces capacity scaling laws for wireless networks and briefly reviews the prior arts in deriving the capacity of VANETs. It then studies the unicast capacity considering the socialized mobility model of VANETs. With vehicles communicating based on a two-hop relaying scheme, the unicast capacity bound is deriv

  6. Satellite communications network design and analysis

    CERN Document Server

    Jo, Kenneth Y

    2011-01-01

    This authoritative book provides a thorough understanding of the fundamental concepts of satellite communications (SATCOM) network design and performance assessments. You find discussions on a wide class of SATCOM networks using satellites as core components, as well as coverage key applications in the field. This in-depth resource presents a broad range of critical topics, from geosynchronous Earth orbiting (GEO) satellites and direct broadcast satellite systems, to low Earth orbiting (LEO) satellites, radio standards and protocols.This invaluable reference explains the many specific uses of

  7. Discovery Monday - Behind the plug: communication networks

    CERN Multimedia

    2004-01-01

    Ever wondered what happens to your email when you click "send"? And when you make a phone call, how does your voice travel down the wire? Find out more about communication networks and their applications. Do not miss the next Discovery Monday in Microcosm on 1st March (see Bulletin 9/2004)! Monday 1st March from 7.30pm to 9.00pm, in Microcosm. Entrance Free.

  8. NOVANET: communications network for a control system

    International Nuclear Information System (INIS)

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

    1983-01-01

    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

  9. Correlated Fluctuations in Strongly Coupled Binary Networks Beyond Equilibrium

    Directory of Open Access Journals (Sweden)

    David Dahmen

    2016-08-01

    Full Text Available Randomly coupled Ising spins constitute the classical model of collective phenomena in disordered systems, with applications covering glassy magnetism and frustration, combinatorial optimization, protein folding, stock market dynamics, and social dynamics. The phase diagram of these systems is obtained in the thermodynamic limit by averaging over the quenched randomness of the couplings. However, many applications require the statistics of activity for a single realization of the possibly asymmetric couplings in finite-sized networks. Examples include reconstruction of couplings from the observed dynamics, representation of probability distributions for sampling-based inference, and learning in the central nervous system based on the dynamic and correlation-dependent modification of synaptic connections. The systematic cumulant expansion for kinetic binary (Ising threshold units with strong, random, and asymmetric couplings presented here goes beyond mean-field theory and is applicable outside thermodynamic equilibrium; a system of approximate nonlinear equations predicts average activities and pairwise covariances in quantitative agreement with full simulations down to hundreds of units. The linearized theory yields an expansion of the correlation and response functions in collective eigenmodes, leads to an efficient algorithm solving the inverse problem, and shows that correlations are invariant under scaling of the interaction strengths.

  10. Community detection based on network communicability

    Science.gov (United States)

    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.

  11. Collaboration and communication in a networked economy

    Directory of Open Access Journals (Sweden)

    Hans-Christian Pfohl

    2015-06-01

    Full Text Available Background: The networked economy is a result of the increasing specialization and productivity. The blurring of company boundaries enables potential for new competitive advantages. However, along with the growing networked economy, the complexity also increases. Methods: With their current study the German logistics association sheds a light on the most important trends of the networked and complex economy and the strategies of logistics and supply chain management (SCM coping with them. Results and conclusions: This paper focuses on the collaboration of actors in logistics and supply chain management and the communication required for being successful. Furthermore, going beyond the study, the role of collaboration for innovation in logistics and SCM is considered, that has been neglected in literature so far. Finally, the paper concludes with a discussion reflecting the current state of collaboration in the context of its potential.

  12. COMMUNICATION MANAGEMENT CRISIS IN SOCIAL NETWORKS

    Directory of Open Access Journals (Sweden)

    Ana Mª Enrique Jiménez

    2013-04-01

    Full Text Available It is often in the social networks where you detect the first signs of a potential crisis situation. Today, many companies decide to be present in social networks to communicate, listen and respond to their audiences openly with immediacy. A simple complaint is visible and propagates through the network in seconds, being capable of generating a negative impact on the corporate image of the organization. The same can happen to the contrary, ie, to praise the performance of a company, which may affect the creation or strengthening of the good reputation of the company. However, we know that this does not happen with the same intensity. In this paper we analyze the decisions and actions of two opposing companies, Nestlé and Panrico, in front of a possible crisis situation.

  13. Testing dimension and nonclassicality in communication networks

    Science.gov (United States)

    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.

  14. On cost-effective communication network designing

    Science.gov (United States)

    Zhang, Guo-Qiang

    2010-02-01

    How to efficiently design a communication network is a paramount task for network designing and engineering. It is, however, not a single objective optimization process as perceived by most previous researches, i.e., to maximize its transmission capacity, but a multi-objective optimization process, with lowering its cost to be another important objective. These two objectives are often contradictive in that optimizing one objective may deteriorate the other. After a deep investigation of the impact that network topology, node capability scheme and routing algorithm as well as their interplays have on the two objectives, this letter presents a systematic approach to achieve a cost-effective design by carefully choosing the three designing aspects. Only when routing algorithm and node capability scheme are elegantly chosen can BA-like scale-free networks have the potential of achieving good tradeoff between the two objectives. Random networks, on the other hand, have the built-in character for a cost-effective design, especially when other aspects cannot be determined beforehand.

  15. Marketing communications model for innovation networks

    Directory of Open Access Journals (Sweden)

    Tiago João Freitas Correia

    2015-10-01

    Full Text Available Innovation is an increasingly relevant concept for the success of any organization, but it also represents a set of internal and external considerations, barriers and challenges to overcome. Along the concept of innovation, new paradigms emerge such as open innovation and co-creation that are simultaneously innovation modifiers and intensifiers in organizations, promoting organizational openness and stakeholder integration within the value creation process. Innovation networks composed by a multiplicity of agents in co-creative work perform as innovation mechanisms to face the increasingly complexity of products, services and markets. Technology, especially the Internet, is an enabler of all process among organizations supported by co-creative platforms for innovation. The definition of marketing communication strategies that promote motivation and involvement of all stakeholders in synergic creation and external promotion is the central aspect of this research. The implementation of the projects is performed by participative workshops with stakeholders from Madan Parque through IDEAS(REVOLUTION methodology and the operational model LinkUp parameterized for the project. The project is divided into the first part, the theoretical framework, and the second part where a model is developed for the marketing communication strategies that appeal to the Madan Parque case study. Keywords: Marketing Communication; Open Innovation, Technology; Innovation Networks; Incubator; Co-Creation.

  16. Extracting Association Patterns in Network Communications

    Directory of Open Access Journals (Sweden)

    Javier Portela

    2015-02-01

    Full Text Available 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.

  17. Supply Networks and Value Creation in High Innovation and Strong Network Externalities Industry

    Directory of Open Access Journals (Sweden)

    Fernando Claro Tomaselli

    2013-12-01

    Full Text Available The rapid developing product and service markets and developments in information technologies have accelerated growth in outsourcing of peripheral activities and critical business as well, enhancing the importance of network supply chain management. This paper analyzes the dynamics of supply chain management and the creation of value in an industry with strong network effects and constantly introduction of disruptive technologies, the videogame industry. This industry evolves at a high velocity, with a lifecycle of five to six years for consoles, which features a new generation of consoles, where new companies and technologies appear and disappear at each generation.

  18. Opportunistic spectrum utilization in vehicular communication networks

    CERN Document Server

    Cheng, Nan

    2016-01-01

    This brief examines current research on improving Vehicular Networks (VANETs), examining spectrum scarcity due to the dramatic growth of mobile data traffic and the limited bandwidth of dedicated vehicular communication bands and the use of opportunistic spectrum bands to mitigate congestion. It reviews existing literature on the use of opportunistic spectrum bands for VANETs, including licensed and unlicensed spectrum bands and a variety of related technologies, such as cognitive radio, WiFi and device-to-device communications. Focused on analyzing spectrum characteristics, designing efficient spectrum exploitation schemes, and evaluating the date delivery performance when utilizing different opportunistic spectrum bands, the results presented in this brief provide valuable insights on improving the design and deployment of future VANETs.

  19. Method of optimization onboard communication network

    Science.gov (United States)

    Platoshin, G. A.; Selvesuk, N. I.; Semenov, M. E.; Novikov, V. M.

    2018-02-01

    In this article the optimization levels of onboard communication network (OCN) are proposed. We defined the basic parameters, which are necessary for the evaluation and comparison of modern OCN, we identified also a set of initial data for possible modeling of the OCN. We also proposed a mathematical technique for implementing the OCN optimization procedure. This technique is based on the principles and ideas of binary programming. It is shown that the binary programming technique allows to obtain an inherently optimal solution for the avionics tasks. An example of the proposed approach implementation to the problem of devices assignment in OCN is considered.

  20. GAS MAIN SENSOR AND COMMUNICATIONS NETWORK SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. Trends in Area of Safety Communications within Industrial Networks

    Directory of Open Access Journals (Sweden)

    Maria Franekova

    2005-01-01

    Full Text Available The paper deals with the problems of safety communication in industrial networks for purpose of assurance of functional safety. It is intents on analysis of treats on industry networks and there is described recommended safety protections and their location into layer communication protocol applicable in fieldbus network, which they are used within safety critical processes control.

  2. Exact tensor network ansatz for strongly interacting systems

    Science.gov (United States)

    Zaletel, Michael P.

    It appears that the tensor network ansatz, while not quite complete, is an efficient coordinate system for the tiny subset of a many-body Hilbert space which can be realized as a low energy state of a local Hamiltonian. However, we don't fully understand precisely which phases are captured by the tensor network ansatz, how to compute their physical observables (even numerically), or how to compute a tensor network representation for a ground state given a microscopic Hamiltonian. These questions are algorithmic in nature, but their resolution is intimately related to understanding the nature of quantum entanglement in many-body systems. For this reason it is useful to compute the tensor network representation of various `model' wavefunctions representative of different phases of matter; this allows us to understand how the entanglement properties of each phase are expressed in the tensor network ansatz, and can serve as test cases for algorithm development. Condensed matter physics has many illuminating model wavefunctions, such as Laughlin's celebrated wave function for the fractional quantum Hall effect, the Bardeen-Cooper-Schrieffer wave function for superconductivity, and Anderson's resonating valence bond ansatz for spin liquids. This thesis presents some results on exact tensor network representations of these model wavefunctions. In addition, a tensor network representation is given for the time evolution operator of a long-range one-dimensional Hamiltonian, which allows one to numerically simulate the time evolution of power-law interacting spin chains as well as two-dimensional strips and cylinders.

  3. The Connect Effect Building Strong Personal, Professional, and Virtual Networks

    CERN Document Server

    Dulworth, Michael

    2008-01-01

    Entrepreneur and executive development expert Mike Dulworth's THE CONNECT EFFECT provides readers with a simple framework and practical tools for developing that crucial competitive advantage: a high-quality personal, professional/organizational and virtual network.

  4. Gas Main Sensor and Communications Network System

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Game theory in communication networks cooperative resolution of interactive networking scenarios

    CERN Document Server

    Antoniou, Josephina

    2012-01-01

    A mathematical tool for scientists and researchers who work with computer and communication networks, Game Theory in Communication Networks: Cooperative Resolution of Interactive Networking Scenarios addresses the question of how to promote cooperative behavior in interactive situations between heterogeneous entities in communication networking scenarios. It explores network design and management from a theoretical perspective, using game theory and graph theory to analyze strategic situations and demonstrate profitable behaviors of the cooperative entities. The book promotes the use of Game T

  6. Discovery Monday - Behind the plug: communication networks

    CERN Multimedia

    2004-01-01

    Ever wondered what happens to your email when you click "send"? And when you make a phone call, how does your voice travel down the wire? Find out more about communication networks and their applications at the next Discovery Monday in Microcosm on 1 March. At CERN, networks are used for a multitude of reasons. Mobile phones, for example, are used in the laboratory's underground areas. Optical fibre cabling ensures that CERN's computers are connected to the rest of the world. But how do optical fibres work and what does the future have in store? CERN's experiments also need networks. Particle detectors are made of many layers, each relays complex information to a computer analysis centre which reconstitutes the passage of the particles resulting from collisions. Many billions of bytes are transmitted every second from a multitude of sources, to many computers.  No single computer can handle such a huge flow of information. The next Discovery Monday is your chance to find out how this works.  Participate i...

  7. HoloNetwork: communicating science through holography

    Science.gov (United States)

    Pombo, Pedro; Santos, Emanuel; Magalhães, Carolina

    2017-03-01

    Since 1997 a program dedicated to holography has been developed and implemented in Portugal. This program started with focus on schools and science education. The HoloNetwork was created and it has been spread at a National level, involving a group of thirty schools and hundreds of students and teachers. In 2009 this network started to work to achieve a new target, the general public. With this goal, a larger program was developed with focus on science and society and on science communication through holography. For the implementation of this new program, special holography outreach activities were built, dedicated to informal learning and seven Science Centers around Portugal were add into the HoloNetwork. During last years, we have been working on holography, based on two main branches, one dedicated to schools and with the aimed to promote physics teaching and to teach how to make holograms, and another dedicated to society and with the aimed to promote holography and to increase scientific literacy. This paper would analyze the educational program, all holography outreach activities, exhibitions or events, all equipments, materials and setups used and it would present the holographic techniques explored with students or with the public. Finally, the results obtained in this work would be present and explored, with focus on students impact and outcomes, taking into account the public engagement on holography and its effect into scientific culture and analyzing the quality of holograms made by students and by the general public. subject.

  8. Network Analysis as a Communication Audit Instrument: Uncovering Communicative Strengths and Weaknesses Within Organizations

    NARCIS (Netherlands)

    Koning, K.H.; de Jong, Menno D.T.

    2015-01-01

    Network analysis is one of the instruments in the communication audit toolbox to diagnose communication problems within organizations. To explore its contribution to a communication audit, the authors conducted a network analysis within three secondary schools, comparing its results with those of

  9. Exploring the morphospace of communication efficiency in complex networks.

    Directory of Open Access Journals (Sweden)

    Joaquín Goñi

    Full Text Available 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.

  10. Detection of strong attractors in social media networks.

    Science.gov (United States)

    Qasem, Ziyaad; Jansen, Marc; Hecking, Tobias; Hoppe, H Ulrich

    2016-01-01

    Detection of influential actors in social media such as Twitter or Facebook plays an important role for improving the quality and efficiency of work and services in many fields such as education and marketing. The work described here aims to introduce a new approach that characterizes the influence of actors by the strength of attracting new active members into a networked community. We present a model of influence of an actor that is based on the attractiveness of the actor in terms of the number of other new actors with which he or she has established relations over time. We have used this concept and measure of influence to determine optimal seeds in a simulation of influence maximization using two empirically collected social networks for the underlying graphs. Our empirical results on the datasets demonstrate that our measure stands out as a useful measure to define the attractors comparing to the other influence measures.

  11. Research on key technology of space laser communication network

    Science.gov (United States)

    Chang, Chengwu; Huang, Huiming; Liu, Hongyang; Gao, Shenghua; Cheng, Liyu

    2016-10-01

    Since the 21st century, Spatial laser communication has made a breakthrough development. Europe, the United States, Japan and other space powers have carried out the test of spatial laser communication technology on-orbit, and put forward a series of plans. In 2011, China made the first technology demonstration of satellite-ground laser communication carried by HY-2 satellite. Nowadays, in order to improve the transmission rate of spatial network, the topic of spatial laser communication network is becoming a research hotspot at home and abroad. This thesis, from the basic problem of spatial laser communication network to solve, analyzes the main difference between spatial network and ground network, which draws forth the key technology of spatial laser communication backbone network, and systematically introduces our research on aggregation, addressing, architecture of spatial network. From the perspective of technology development status and trends, the thesis proposes the development route of spatial laser communication network in stages. So as to provide reference about the development of spatial laser communication network in China.

  12. Educational network comparative analysis of small groups: Short- and long-term communications

    Science.gov (United States)

    Berg, D. B.; Zvereva, O. M.; Nazarova, Yu. Yu.; Chepurov, E. G.; Kokovin, A. V.; Ranyuk, S. V.

    2017-11-01

    The present study is devoted to the discussion of small group communication network structures. These communications were observed in student groups, where actors were united with a regular educational activity. The comparative analysis was carried out for networks of short-term (1 hour) and long-term (4 weeks) communications, it was based on seven structural parameters, and consisted of two stages. At the first stage, differences between the network graphs were examined, and the random corresponding Bernoulli graphs were built. At the second stage, revealed differences were compared. Calculations were performed using UCINET software framework. It was found out that networks of long-term and short-term communications are quite different: the structure of a short-term communication network is close to a random one, whereas the most of long-term communication network parameters differ from the corresponding random ones by more than 30%. This difference can be explained by strong "noisiness" of a short-term communication network, and the lack of social in it.

  13. Control and estimation methods over communication networks

    CERN Document Server

    Mahmoud, Magdi S

    2014-01-01

    This book provides a rigorous framework in which to study problems in the analysis, stability and design of networked control systems. Four dominant sources of difficulty are considered: packet dropouts, communication bandwidth constraints, parametric uncertainty, and time delays. Past methods and results are reviewed from a contemporary perspective, present trends are examined, and future possibilities proposed. Emphasis is placed on robust and reliable design methods. New control strategies for improving the efficiency of sensor data processing and reducing associated time delay are presented. The coverage provided features: ·        an overall assessment of recent and current fault-tolerant control algorithms; ·        treatment of several issues arising at the junction of control and communications; ·        key concepts followed by their proofs and efficient computational methods for their implementation; and ·        simulation examples (including TrueTime simulations) to...

  14. Novel Concepts for Device to Device Communication using Network Coding

    DEFF Research Database (Denmark)

    Pahlevani, Peyman; Hundebøll, Martin; Pedersen, Morten Videbæk

    2014-01-01

    Device-to-device communication is currently a hot research topic within 3GPP. Even though D2D communication has been part of previous ad hoc, meshed and sensor networks proposals, the main contribution by 3GPP is that the direct communication among two devices is carried out over a dynamically...... assigned, licensed spectrum; thus, it is under full control of the cellular network. D2D communication creates a market potential for new services, new approaches to efficient spectrum use, and security concepts. This is especially true if D2D communication is extended to larger communication groups...... organized in meshed clusters. In this article, we discuss the potential and shortcomings of D2D communication as proposed today, advocating for the use of network coding as an enabling technology for enhanced security and communication efficiency using the PlayNCool and CORE protocols as key examples...

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

    Science.gov (United States)

    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.

  16. Modern communication and social networks on the labor market

    OpenAIRE

    Kravchenko, Natalia

    2011-01-01

    Evaluation of social and communication networks as a mean of career controlling in modern conditions in Russia. Traits of virtual social relations, importance of social and communication resources for career development and job searching. Analysis of these networks effectiveness in professional life.

  17. Collaborative Algorithms for Communication in Wireless Sensor Networks

    NARCIS (Netherlands)

    Nieberg, T.; Dulman, S.O.; Havinga, Paul J.M.; van Hoesel, L.F.W.; Wu Jian, W.J.; Basten, Twan; Geilen, Marc; de Groot, Harmke

    2003-01-01

    In this paper, we present the design of the communication in a wireless sensor network. The resource limitations of a wireless sensor network, especially in terms of energy, require an integrated, and collaborative approach for the different layers of communication. In particular, energy-efficient

  18. Collaborative Algortihms for Communication in Wireless Sensor Networks

    NARCIS (Netherlands)

    Nieberg, T.; Dulman, S.O.; Havinga, Paul J.M.; van Hoesel, L.F.W.; Wu Jian, W.J.

    In this paper, we present the design of the communication in a wireless sensor network. The resource limitations of a wireless sensor network, especially in terms of energy, require an integrated, and collaborative approach for the different layers of communication. In particular, energy-efficient

  19. A reappraisal of the concept of the strong/weak force networks for granular materials

    NARCIS (Netherlands)

    Kruyt, Nicolaas P.

    2015-01-01

    The concept of the strong/weak force networks for granular materials has been proposed by Radjai et al [2]. The weak (strong) contact network consists of the contacts where the normal force is smaller (larger) than the average normal force. Based on results of particle simulations, Radjai et al [2

  20. What Factors Predict Who Will Have a Strong Social Network Following a Stroke?

    Science.gov (United States)

    Northcott, Sarah; Marshall, Jane; Hilari, Katerina

    2016-01-01

    Purpose: Measures of social networks assess the number and nature of a person's social contacts, and strongly predict health outcomes. We explored how social networks change following a stroke and analyzed concurrent and baseline predictors of social networks 6 months poststroke. Method: We conducted a prospective longitudinal observational study.…

  1. ON SECURE FULL DUPLEX COMMUNICATION IN MOBILE AD HOC NETWORK

    OpenAIRE

    S. C. Dutta; Sudha Singh; D. K. Singh

    2013-01-01

    This paper is to establish Ad Hoc network in mobile phones and start fully secured full duplex communication in any situation. This type of communication will be cost effective and it will be fastest way of communication in case of any server failure or server error.

  2. Distributed Optimization of Multi Beam Directional Communication Networks

    Science.gov (United States)

    2017-06-30

    Distributed Optimization of Multi-Beam Directional Communication Networks Theodoros Tsiligkaridis MIT Lincoln Laboratory Lexington, MA 02141, USA...based routing. I. INTRODUCTION Missions where multiple communication goals are of in- terest are becoming more prevalent in military applications...Multilayer communications may occur within a coalition; for example, a team consisting of ground vehicles and an airborne set of assets may desire to

  3. ON SECURE FULL DUPLEX COMMUNICATION IN MOBILE AD HOC NETWORK

    Directory of Open Access Journals (Sweden)

    S. C. Dutta

    2013-06-01

    Full Text Available This paper is to establish Ad Hoc network in mobile phones and start fully secured full duplex communication in any situation. This type of communication will be cost effective and it will be fastest way of communication in case of any server failure or server error.

  4. A fusion networking model for smart grid power distribution backbone communication network based on PTN

    Directory of Open Access Journals (Sweden)

    Wang Hao

    2016-01-01

    Full Text Available In current communication network for distribution in Chinese power grid systems, the fiber communication backbone network for distribution and TD-LTE power private wireless backhaul network of power grid are both bearing by the SDH optical transmission network, which also carries the communication network of transformer substation and main electric. As the data traffic of the distribution communication and TD-LTE power private wireless network grow rapidly in recent years, it will have a big impact with the SDH network’s bearing capacity which is mainly used for main electric communication in high security level. This paper presents a fusion networking model which use a multiple-layer PTN network as the unified bearing of the TD-LTE power private wireless backhaul network and fiber communication backbone network for distribution. Network dataflow analysis shows that this model can greatly reduce the capacity pressure of the traditional SDH network as well as ensure the reliability of the transmission of the communication network for distribution and TD-LTE power private wireless network.

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

    Science.gov (United States)

    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…

  6. Large deviations for Gaussian queues modelling communication networks

    CERN Document Server

    Mandjes, Michel

    2007-01-01

    Michel Mandjes, Centre for Mathematics and Computer Science (CWI) Amsterdam, The Netherlands, and Professor, Faculty of Engineering, University of Twente. At CWI Mandjes is a senior researcher and Director of the Advanced Communications Network group.  He has published for 60 papers on queuing theory, networks, scheduling, and pricing of networks.

  7. Consensus in the network with uniform constant communication delay

    NARCIS (Netherlands)

    Wang, Xu; Saberi, Ali; Stoorvogel, Antonie Arij; Grip, H°avard Fjær; Yang, Tao

    2013-01-01

    This paper studies consensus among identical agents that are at most critically unstable and coupled through networks with uniform constant communication delay. An upper bound for delay tolerance is obtained which explicitly depends on agent dynamics and network topology. The dependence on network

  8. Low power radio communication platform for wireless sensor network

    NARCIS (Netherlands)

    Dutta, R.; Bentum, Marinus Jan; van der Zee, Ronan A.R.; Kokkeler, Andre B.J.

    2009-01-01

    Wireless sensor networks are predicted to be the most versatile, popular and useful technology in the near future. A large number of applications are targeted which will hugely benefit from a network of tiny computers with few sensors, radio communication platform, intelligent networking and

  9. E-SAP: Efficient-Strong Authentication Protocol for Healthcare Applications Using Wireless Medical Sensor Networks

    Directory of Open Access Journals (Sweden)

    Hoon-Jae Lee

    2012-02-01

    Full Text Available A wireless medical sensor network (WMSN can sense humans’ physiological signs without sacrificing patient comfort and transmit patient vital signs to health professionals’ hand-held devices. The patient physiological data are highly sensitive and WMSNs are extremely vulnerable to many attacks. Therefore, it must be ensured that patients’ medical signs are not exposed to unauthorized users. Consequently, strong user authentication is the main concern for the success and large scale deployment of WMSNs. In this regard, this paper presents an efficient, strong authentication protocol, named E-SAP, for healthcare application using WMSNs. The proposed E-SAP includes: (1 a two-factor (i.e., password and smartcard professional authentication; (2 mutual authentication between the professional and the medical sensor; (3 symmetric encryption/decryption for providing message confidentiality; (4 establishment of a secure session key at the end of authentication; and (5 professionals can change their password. Further, the proposed protocol requires three message exchanges between the professional, medical sensor node and gateway node, and achieves efficiency (i.e., low computation and communication cost. Through the formal analysis, security analysis and performance analysis, we demonstrate that E-SAP is more secure against many practical attacks, and allows a tradeoff between the security and the performance cost for healthcare application using WMSNs.

  10. Adaptive Network Coding in Wireless Communications

    DEFF Research Database (Denmark)

    2017-01-01

    A first network node (eNB) is configured to receive (404), from a second network node (UE), channel performance indicator values regarding a serving cell, and estimate (404) a number of network-coded packets based on the received channel performance indicator values, such that the estimated number...... of network-coded packets defines a number of network-coded packets required by the second network node for successful detection of payload data. The second network node is configured to generate (402) the value of a channel performance indicator regarding the serving cell, and cause (403) transmission...... of the generated value of the channel performance indicator to the first network node, wherein the generated value of the channel performance indicator directly or indirectly indicates the number of network-coded packets required by the second network node for successful reception of payload data that is an input...

  11. Do learning collaboratives strengthen communication? A comparison of organizational team communication networks over time.

    Science.gov (United States)

    Bunger, Alicia C; Lengnick-Hall, Rebecca

    Collaborative learning models were designed to support quality improvements, such as innovation implementation by promoting communication within organizational teams. Yet the effect of collaborative learning approaches on organizational team communication during implementation is untested. The aim of this study was to explore change in communication patterns within teams from children's mental health organizations during a year-long learning collaborative focused on implementing a new treatment. We adopt a social network perspective to examine intraorganizational communication within each team and assess change in (a) the frequency of communication among team members, (b) communication across organizational hierarchies, and (c) the overall structure of team communication networks. A pretest-posttest design compared communication among 135 participants from 21 organizational teams at the start and end of a learning collaborative. At both time points, participants were asked to list the members of their team and rate the frequency of communication with each along a 7-point Likert scale. Several individual, pair-wise, and team level communication network metrics were calculated and compared over time. At the individual level, participants reported communicating with more team members by the end of the learning collaborative. Cross-hierarchical communication did not change. At the team level, these changes manifested differently depending on team size. In large teams, communication frequency increased, and networks grew denser and slightly less centralized. In small teams, communication frequency declined, growing more sparse and centralized. Results suggest that team communication patterns change minimally but evolve differently depending on size. Learning collaboratives may be more helpful for enhancing communication among larger teams; thus, managers might consider selecting and sending larger staff teams to learning collaboratives. This study highlights key future

  12. Communication Network Architectures Based on Ethernet Passive Optical Network for Offshore Wind Power Farms

    Directory of Open Access Journals (Sweden)

    Mohamed A. Ahmed

    2016-03-01

    Full Text Available Nowadays, with large-scale offshore wind power farms (WPFs becoming a reality, more efforts are needed to maintain a reliable communication network for WPF monitoring. Deployment topologies, redundancy, and network availability are the main items to enhance the communication reliability between wind turbines (WTs and control centers. Traditional communication networks for monitoring and control (i.e., supervisory control and data acquisition (SCADA systems using switched gigabit Ethernet will not be sufficient for the huge amount of data passing through the network. In this paper, the optical power budget, optical path loss, reliability, and network cost of the proposed Ethernet Passive Optical Network (EPON-based communication network for small-size offshore WPFs have been evaluated for five different network architectures. The proposed network model consists of an optical network unit device (ONU deployed on the WT side for collecting data from different internal networks. All ONUs from different WTs are connected to a central optical line terminal (OLT, placed in the control center. There are no active electronic elements used between the ONUs and the OLT, which reduces the costs and complexity of maintenance and deployment. As fiber access networks without any protection are characterized by poor reliability, three different protection schemes have been configured, explained, and discussed. Considering the cost of network components, the total implementation expense of different architectures with, or without, protection have been calculated and compared. The proposed network model can significantly contribute to the communication network architecture for next generation WPFs.

  13. New Communication Network Protocol for a Data Acquisition System

    Science.gov (United States)

    Uchida, T.; Fujii, H.; Nagasaka, Y.; Tanaka, M.

    2006-02-01

    An event builder based on communication networks has been used in high-energy physics experiments, and various networks have been adopted, for example, IEEE 802.3 (Ethernet), asynchronous transfer mode (ATM), and so on. In particular, Ethernet is widely used because its infrastructure is very cost effective. Many systems adopt standard protocols that are designed for a general network. However, in the case of an event builder, the communication pattern between stations is different from that in a general network. The unique communication pattern causes congestion, and thus makes it difficulty to quantitatively design the network. To solve this problem, we have developed a simple network protocol for a data acquisition (DAQ) system. The protocol is designed to keep the sequence of senders so that no congestion occurs. We implemented the protocol on a small hardware component [a field programmable gate array (FPGA)] and measured the performance, so that it will be ready for a generic DAQ system

  14. 5th International Conference on Electronics, Communications and Networks

    CERN Document Server

    2016-01-01

    This book comprises peer-reviewed contributions presented at the 5th International Conference on Electronics, Communications and Networks (CECNet 2015), held in Shanghai, China, 12-15 December, 2015. It includes new multi-disciplinary topics spanning a unique depth and breadth of cutting-edge research areas in Electronic Engineering, Communications and Networks, and Computer Technology. More generally, it is of interest to academics, students and professionals involved in Consumer Electronics Technology, Communication Engineering and Technology, Wireless Communication Systems and Technology, and Computer Engineering and Technology.

  15. Synchronization and bidirectional communication without delay line using strong mutually coupled semiconductor lasers

    Science.gov (United States)

    Li, Guang-Hui; Wang, An-Bang; Feng, Ye; Wang, Yang

    2010-07-01

    This paper numerically demonstrates synchronization and bidirectional communication without delay line by using two semiconductor lasers with strong mutual injection in a face-to-face configuration. These results show that both of the two lasers' outputs synchronize with their input chaotic carriers. In addition, simulations demonstrate that this kind of synchronization can be used to realize bidirectional communications without delay line. Further studies indicate that within a small deviation in message amplitudes of two sides (±6%), the message can be extracted with signal-noise-ratio more than 10 dB; and the signal-noise-ratio is extremely sensitive to the message rates mismatch of two sides, which may be used as a key of bidirectional communication.

  16. Reducing Communication Overhead by Scheduling TCP Transfers on Mobile Devices using Wireless Network Performance Maps

    DEFF Research Database (Denmark)

    Højgaard-Hansen, Kim; Madsen, Tatiana Kozlova; Schwefel, Hans-Peter

    2012-01-01

    The performance of wireless communication networks has been shown to have a strong location dependence. Measuring the performance while having accurate location information available makes it possible to generate performance maps. In this paper we propose a framework for the generation and use of...

  17. Fiber-Optic Terahertz Data-Communication Networks

    Science.gov (United States)

    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.

  18. Cryptanalysis and improvement of quantum secure communication network protocol with entangled photons for mobile communications

    International Nuclear Information System (INIS)

    Gao, Gan

    2014-01-01

    Recently, a communication protocol called controlled bidirectional quantum secret direct communication for mobile networks was proposed by Chou et al (2014 Mobile Netw. Appl. 19 121). We study the security of the proposed communication protocol and find that it is not secure. The controller, Telecom Company, may eavesdrop secret messages from mobile devices without being detected. Finally, we give a possible improvement of the communication protocol. (paper)

  19. Wideband autonomous cognitive radios for networked satellites communications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — There is growing recognition that success in a variety of space mission types can be greatly enhanced by making current communication transceivers and networks...

  20. 2014 International Conference on Wireless Communications, Networking and Applications

    CERN Document Server

    2016-01-01

    This book is based on a series of conferences on Wireless Communications, Networking and Applications that have been held on December 27-28, 2014 in Shenzhen, China. The meetings themselves were a response to technological developments in the areas of wireless communications, networking and applications and facilitate researchers, engineers and students to share the latest research results and the advanced research methods of the field. The broad variety of disciplines involved in this research and the differences in approaching the basic problems are probably typical of a developing field of interdisciplinary research. However, some main areas of research and development in the emerging areas of wireless communication technology can now be identified. The contributions to this book are mainly selected from the papers of the conference on wireless communications, networking and applications and reflect the main areas of interest: Section 1 - Emerging Topics in Wireless and Mobile Computing and Communications...

  1. Advanced communication and network requirements in Europe

    DEFF Research Database (Denmark)

    Falch, Morten; Enemark, Rasmus

    The report address diffusion of new tele-application, focusing on potential use and potential tele-trafic genrated as a consequense. The applications investigated are: Teleworking, distance learning, research and university network, applications aimed at SMEs, health networks, a trans European pu...... public administation network, city information highway, road-trafic manegement, air traffic control and electronic quotation....

  2. Communication on the structure of biological networks

    Indian Academy of Sciences (India)

    An epidemic can also spread faster in neuronal networks than in the other biological networks studied here. Thus, the underlying undirected architecture of a neuronal network possesses certain conformation which is favourable for spreading different entities or information. Now, to explore the topological characteristics that ...

  3. Army Social Media: Harnessing the Power of Networked Communications

    Science.gov (United States)

    2011-09-01

    9/1/2011 Army Social Media : harnessing the power of networked communications Report Documentation Page Form ApprovedOMB No. 0704-0188 Public...4. TITLE AND SUBTITLE Army Social Media : harnessing the power of networked communications 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM...the Chief of Public Affairs,Online and Social Media Division,1500 Pentagon,Washington,DC,20301 8. PERFORMING ORGANIZATION REPORT NUMBER 9

  4. Utility communication networks and services specification, deployment and operation

    CERN Document Server

    2017-01-01

    This CIGRE green book begins by addressing the specification and provision of communication services in the context of operational applications for electrical power utilities, before subsequently providing guidelines on the deployment or transformation of networks to deliver these specific communication services. Lastly, it demonstrates how these networks and their services can be monitored, operated, and maintained to ensure that the requisite high level of service quality is consistently achieved.

  5. Mesh Network Architecture for Enabling Inter-Spacecraft Communication

    Science.gov (United States)

    Becker, Christopher; Merrill, Garrick

    2017-01-01

    To enable communication between spacecraft operating in a formation or small constellation, a mesh network architecture was developed and tested using a time division multiple access (TDMA) communication scheme. The network is designed to allow for the exchange of telemetry and other data between spacecraft to enable collaboration between small spacecraft. The system uses a peer-to-peer topology with no central router, so that it does not have a single point of failure. The mesh network is dynamically configurable to allow for addition and subtraction of new spacecraft into the communication network. Flight testing was performed using an unmanned aerial system (UAS) formation acting as a spacecraft analogue and providing a stressing environment to prove mesh network performance. The mesh network was primarily devised to provide low latency, high frequency communication but is flexible and can also be configured to provide higher bandwidth for applications desiring high data throughput. The network includes a relay functionality that extends the maximum range between spacecraft in the network by relaying data from node to node. The mesh network control is implemented completely in software making it hardware agnostic, thereby allowing it to function with a wide variety of existing radios and computing platforms..

  6. True Nature of Supply Network Communication Structure

    Directory of Open Access Journals (Sweden)

    Lokhman Hakim bin Osman

    2016-04-01

    Full Text Available Globalization of world economy has altered the definition of organizational structure. Global supply chain can no longer be viewed as an arm-length structure. It has become more complex. The complexity demands deeper research and understanding. This research analyzed a structure of supply network in an attempt to elucidate the true structure of the supply network. Using the quantitative Social Network Analysis methodology, findings of this study indicated that, the structure of the supply network differs depending on the types of network relations. An important implication of these findings would be a more focus resource management upon network relationship development that is based on firms’ positions in the different network structure. This research also contributes to the various strategies of effective and efficient supply chain management.

  7. Understanding Team Communication Characteristics using Social Network Analysis

    International Nuclear Information System (INIS)

    Kim, Ar Ryum; Lee, Seung Woo; Seong, Poong Hyun; Park, Jin Kyun

    2011-01-01

    An important aspect of human behavior in nuclear power plants (NPPs) is team interaction since operating NPPs involves the coordination of several team members among and within workplaces. Since operators in main control room (MCR) get a great deal of information through communication to perform a task, communication is one of the important characteristics for team characteristics. Many researchers have been studying how to understand the characteristics of communication. Social network analysis (SNA) which is considered as an objective and easily applicable method has been already applied in many fields to investigate characteristics of team communication. Henttonen (2010) has struggled to perform the research on the impact of social networks in a team and he found some team communication characteristics could be obtained using some properties of SNA. In this paper, SNA is used to understand communication characteristics within operators in NPPs

  8. Single-shot secure quantum network coding on butterfly network with free public communication

    Science.gov (United States)

    Owari, Masaki; Kato, Go; Hayashi, Masahito

    2018-01-01

    Quantum network coding on the butterfly network has been studied as a typical example of quantum multiple cast network. We propose a secure quantum network code for the butterfly network with free public classical communication in the multiple unicast setting under restricted eavesdropper’s power. This protocol certainly transmits quantum states when there is no attack. We also show the secrecy with shared randomness as additional resource when the eavesdropper wiretaps one of the channels in the butterfly network and also derives the information sending through public classical communication. Our protocol does not require verification process, which ensures single-shot security.

  9. Does the upgrading of the radio communications network in health ...

    African Journals Online (AJOL)

    In an attempt to strengthen the obstetric referral system, the Safe Motherhood Project installed a repeater-based VHF radio communication system in three pilot districts. The overall goal of the new network was to enable the health centers to communicate directly to their district health offices (DHOs) for an ambulance when ...

  10. Rattlesnake: A Network for Real-Time Multimedia Communications

    NARCIS (Netherlands)

    Smit, Gerardus Johannes Maria; Havinga, Paul J.M.; Smit, M.J.P.; Smit, Michel J.P.

    In this extended abstract we describe the design of a local area network suitable for distributed multimedia communications. Multimedia applications require a communication infrastructure with capabilities beyond the current state of the art : real-time stream traffic, small end-to-end latency with

  11. Synchrophasor Sensor Networks for Grid Communication and Protection.

    Science.gov (United States)

    Gharavi, Hamid; Hu, Bin

    2017-07-01

    This paper focuses primarily on leveraging synchronized current/voltage amplitudes and phase angle measurements to foster new categories of applications, such as improving the effectiveness of grid protection and minimizing outage duration for distributed grid systems. The motivation for such an application arises from the fact that with the support of communication, synchronized measurements from multiple sites in a grid network can greatly enhance the accuracy and timeliness of identifying the source of instabilities. The paper first provides an overview of synchrophasor networks and then presents techniques for power quality assessment, including fault detection and protection. To achieve this we present a new synchrophasor data partitioning scheme that is based on the formation of a joint space and time observation vector. Since communication is an integral part of synchrophasor networks, the newly adopted wireless standard for machine-to-machine (M2M) communication, known as IEEE 802.11ah, has been investigated. The paper also presents a novel implementation of a hardware in the loop testbed for real-time performance evaluation. The purpose is to illustrate the use of both hardware and software tools to verify the performance of synchrophasor networks under more realistic environments. The testbed is a combination of grid network modeling, and an Emulab-based communication network. The combined grid and communication network is then used to assess power quality for fault detection and location using the IEEE 39-bus and 390-bus systems.

  12. Synchronization and a secure communication scheme using optical star network

    Science.gov (United States)

    Jeeva Sathya Theesar, S.; Ariffin, M. R. K.; Banerjee, Santo

    2013-12-01

    This work aims to show the effect of synchronization phenomena in multi-nodal star optical network topology as well as to develop an efficient symmetric cryptosystem utilizing available parameters. The optical network is based on chaotic semiconductor laser (SL) systems described by dimensionless modified Lang-Kobayashi's (L-K) delay differential equations. The network nodes are mutually connected with a central semiconductor laser hub with bidirectional linear optical feedback. It has been observed that the laser output can be modulated using a star network setup. The laser intensity increases with the number of nodes and its much more higher than the same for solitary laser, keeping all other inputs as constant. So the network topology is an effective way to optimize the output power. The process by each nodes into the network is illustrated graphically for three, five and seven SLs, respectively. Also the whole network can be implemented as an optical communication system for transmission of signals. Each SL can act as a transceiver during communication. The communication process is examined using a chaotic signal as a plaintext connected with the SL hub and successfully provided a symmetrically secure mechanism upon the communication protocol. The result shows the optimization of output power with the increment of the number of nodes. Also the communication scheme can successfully decode the encrypted signal from SL Hub, at each other nodes.

  13. A note on the consensus finding problem in communication networks with switching topologies

    KAUST Repository

    Haskovec, Jan

    2014-05-07

    In this note, we discuss the problem of consensus finding in communication networks of agents with dynamically switching topologies. In particular, we consider the case of directed networks with unbalanced matrices of communication rates. We formulate sufficient conditions for consensus finding in terms of strong connectivity of the underlying directed graphs and prove that, given these conditions, consensus is found asymptotically. Moreover, we show that this consensus is an emergent property of the system, being encoded in its dynamics and not just an invariant of its initial configuration. © 2014 © 2014 Taylor & Francis.

  14. Socioeconomic correlations and stratification in social-communication networks.

    Science.gov (United States)

    Leo, Yannick; Fleury, Eric; Alvarez-Hamelin, J Ignacio; Sarraute, Carlos; Karsai, Márton

    2016-12-01

    The uneven distribution of wealth and individual economic capacities are among the main forces, which shape modern societies and arguably bias the emerging social structures. However, the study of correlations between the social network and economic status of individuals is difficult due to the lack of large-scale multimodal data disclosing both the social ties and economic indicators of the same population. Here, we close this gap through the analysis of coupled datasets recording the mobile phone communications and bank transaction history of one million anonymized individuals living in a Latin American country. We show that wealth and debt are unevenly distributed among people in agreement with the Pareto principle; the observed social structure is strongly stratified, with people being better connected to others of their own socioeconomic class rather than to others of different classes; the social network appears to have assortative socioeconomic correlations and tightly connected 'rich clubs'; and that individuals from the same class live closer to each other but commute further if they are wealthier. These results are based on a representative, society-large population, and empirically demonstrate some long-lasting hypotheses on socioeconomic correlations, which potentially lay behind social segregation, and induce differences in human mobility. © 2016 The Author(s).

  15. Reliable Communication in Wireless Meshed Networks using Network Coding

    DEFF Research Database (Denmark)

    Pahlevani, Peyman; Paramanathan, Achuthan; Hundebøll, Martin

    2012-01-01

    The advantages of network coding have been extensively studied in the field of wireless networks. Integrating network coding with existing IEEE 802.11 MAC layer is a challenging problem. The IEEE 802.11 MAC does not provide any reliability mechanisms for overheard packets. This paper addresses...

  16. Communications network design and costing model users manual

    Science.gov (United States)

    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.

  17. Communications network design and costing model programmers manual

    Science.gov (United States)

    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.

  18. Cognitive Radio Networks for Tactical Wireless Communications

    Science.gov (United States)

    2014-12-01

    three layers of the OSI protocol stack, the physical layer (layer 1) through the network layer (layer 3). The basic waveform, or common base of...radio technologies. It is organized in a network of CR nodes comprised of USRP modules. These nodes may be connected via RF switch matrix that models ...radio network , new modelling , simulation and evaluation capabilities are required. A phased introduction of cognitive radio technologies is

  19. Designing communication and remote controlling of virtual instrument network system

    International Nuclear Information System (INIS)

    Lei Lin; Wang Houjun; Zhou Xue; Zhou Wenjian

    2005-01-01

    In this paper, a virtual instrument network through the LAN and finally remote control of virtual instruments is realized based on virtual instrument and LabWindows/CVI software platform. The virtual instrument network system is made up of three subsystems. There are server subsystem, telnet client subsystem and local instrument control subsystem. This paper introduced virtual instrument network structure in detail based on LabWindows. Application procedure design of virtual instrument network communication, the Client/the programming mode of the server, remote PC and server communication far realizing, the control power of the workstation is transmitted, server program and so on essential technical were introduced. And virtual instruments network may connect to entire Internet on. Above-mentioned technology, through measuring the application in the electronic measurement virtual instrument network that is already built up, has verified the actual using value of the technology. Experiment and application validate that this design is resultful

  20. Quantum communication network utilizing quadripartite entangled states of optical field

    International Nuclear Information System (INIS)

    Shen Heng; Su Xiaolong; Jia Xiaojun; Xie Changde

    2009-01-01

    We propose two types of quantum dense coding communication networks with optical continuous variables, in which a quadripartite entangled state of the optical field with totally three-party correlations of quadrature amplitudes is utilized. In the networks, the exchange of information between any two participants can be manipulated by one or two of the remaining participants. The channel capacities for a variety of communication protocols are numerically calculated. Due to the fact that the quadripartite entangled states applied in the communication systems have been successfully prepared already in the laboratory, the proposed schemes are experimentally accessible at present.

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

    Directory of Open Access Journals (Sweden)

    Michael D Conover

    Full Text Available 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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  4. Crossbar Switches For Optical Data-Communication Networks

    Science.gov (United States)

    Monacos, Steve P.

    1994-01-01

    Optoelectronic and electro-optical crossbar switches called "permutation engines" (PE's) developed to route packets of data through fiber-optic communication networks. Basic network concept described in "High-Speed Optical Wide-Area Data-Communication Network" (NPO-18983). Nonblocking operation achieved by decentralized switching and control scheme. Each packet routed up or down in each column of this 5-input/5-output permutation engine. Routing algorithm ensures each packet arrives at its designated output port without blocking any other packet that does not contend for same output port.

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

    Science.gov (United States)

    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.

  6. Message transfer in a communication network

    Indian Academy of Sciences (India)

    Examples of transport processes on networks include the traffic of informa- tion packets [1–4], transport processes on biological networks [5,6], and road traffic. ... for this system. In the case of single message transfer, we study the dependence of average travel times on the hub density, and find that travel times fall off as a.

  7. Communication on the structure of biological networks

    Indian Academy of Sciences (India)

    from five different classes (neuronal, food web, protein–protein interaction, metabolism and gene regulation) and ..... food webs show good expansion property (see table 1) unlike other biological networks. The distribution of distances ..... tion is very fast on a network having high degree nodes. Later on, it was shown that.

  8. 2nd International Conference on Green Communications and Networks 2012

    CERN Document Server

    Ma, Maode; GCN 2012

    2013-01-01

    The objective of the 2nd International Conference on Green Communications and Networks 2012 (GCN 2012) is to facilitate an exchange of information on best practices for the latest research advances in the area of communications, networks and intelligence applications. These mainly involve computer science and engineering, informatics, communications and control, electrical engineering, information computing, and business intelligence and management. Proceedings of the 2nd International Conference on Green Communications and Networks 2012 (GCN 2012) will focus on green information technology and applications, which will provide in-depth insights for engineers and scientists in academia, industry, and government. The book addresses the most innovative research developments including technical challenges, social and economic issues, and presents and discusses the authors’ ideas, experiences, findings, and current projects on all aspects of advanced green information technology and applications. Yuhang Yang is ...

  9. Emergence of communication in socio-biological networks

    CERN Document Server

    Berea, Anamaria

    2018-01-01

    This book integrates current advances in biology, economics of information and linguistics research through applications using agent-based modeling and social network analysis to develop scenarios of communication and language emergence in the social aspects of biological communications. The book presents a model of communication emergence that can be applied both to human and non-human living organism networks. The model is based on economic concepts and individual behavior fundamental for the study of trust and reputation networks in social science, particularly in economics; it is also based on the theory of the emergence of norms and historical path dependence that has been influential in institutional economics. Also included are mathematical models and code for agent-based models to explore various scenarios of language evolution, as well as a computer application that explores language and communication in biological versus social organisms, and the emergence of various meanings and grammars in human ...

  10. <strong>Benefits and Barriers of Information and Communication Technologies Adoption in Facilities Management Services Supply Chainstrong>

    DEFF Research Database (Denmark)

    Scupola, Ada

      This paper presents the results of a study of factors impacting information and communication technology (ICT) adoption in the supply chain of facilities management services. The research questions addressed in this study are: What are the key factors that influence adoption and assimilation of...

  11. Power, Avionics and Software Communication Network Architecture

    Science.gov (United States)

    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).

  12. Proceedings of International Conference on Communication and Networks

    CERN Document Server

    Verma, Pramode; Trivedi, Bhushan

    2017-01-01

    The volume contains 75 papers presented at International Conference on Communication and Networks (COMNET 2015) held during February 19–20, 2016 at Ahmedabad Management Association (AMA), Ahmedabad, India and organized by Computer Society of India (CSI), Ahmedabad Chapter, Division IV and Association of Computing Machinery (ACM), Ahmedabad Chapter. The book aims to provide a forum to researchers to propose theory and technology on the networks and services, share their experience in IT and telecommunications industries and to discuss future management solutions for communication systems, networks and services. It comprises of original contributions from researchers describing their original, unpublished, research contribution. The papers are mainly from 4 areas – Security, Management and Control, Protocol and Deployment, and Applications. The topics covered in the book are newly emerging algorithms, communication systems, network standards, services, and applications. .

  13. Training resonant communicators. From raining resonant communicators. From neural networks to network society

    Directory of Open Access Journals (Sweden)

    Gotzon Toral Madariaga

    2013-02-01

    Full Text Available 0 0 1 121 669 USAL 5 1 789 14.0 Normal 0 21 false false false ES JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:Calibri; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-ansi-language:ES; mso-fareast-language:EN-US;} Media control is no longer exclusively in the hands of professional broadcasters. New educational projects must empower users so that they can exercise their digital citizenship. As well as acquiring essential technical skills to move in an interconnected world, emotional literacy is also indispensable for people to desire to take part effectively in this augmented community. So, besides teaching audiovisual technology, this project seeks to re-program the relationship that students develop with a situation that is typically stressful. We propose an expanded practice that enables students to recognize and voluntarily activate their communication biology. This way, users can become actors in new communication networks, and global communication flow will be more plural and richer.

  14. Enhanced Communication Network Solution for Positive Train Control Implementation

    Science.gov (United States)

    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.

  15. Validation of network communicability metrics for the analysis of brain structural networks.

    Directory of Open Access Journals (Sweden)

    Jennifer Andreotti

    Full Text Available Computational network analysis provides new methods to analyze the brain's structural organization based on diffusion imaging tractography data. Networks are characterized by global and local metrics that have recently given promising insights into diagnosis and the further understanding of psychiatric and neurologic disorders. Most of these metrics are based on the idea that information in a network flows along the shortest paths. In contrast to this notion, communicability is a broader measure of connectivity which assumes that information could flow along all possible paths between two nodes. In our work, the features of network metrics related to communicability were explored for the first time in the healthy structural brain network. In addition, the sensitivity of such metrics was analysed using simulated lesions to specific nodes and network connections. Results showed advantages of communicability over conventional metrics in detecting densely connected nodes as well as subsets of nodes vulnerable to lesions. In addition, communicability centrality was shown to be widely affected by the lesions and the changes were negatively correlated with the distance from lesion site. In summary, our analysis suggests that communicability metrics that may provide an insight into the integrative properties of the structural brain network and that these metrics may be useful for the analysis of brain networks in the presence of lesions. Nevertheless, the interpretation of communicability is not straightforward; hence these metrics should be used as a supplement to the more standard connectivity network metrics.

  16. A Communication network for LHC detector readout

    International Nuclear Information System (INIS)

    Romero, L.

    1993-01-01

    This paper describe a network architecture for data taking in LHC environment. The network is composed of 64 rings of point to point links working at 100 Mbytes/s. The network connect the front end electronics, computer farms and two data switches. The efficiency of the system is discussed. Using extracted 1 Kbyte events for the 2nd level trigger and whole 1 Mbyte events for the 3rd level trigger, then the system can sustain working rates of 2 x 10''5 and 2 x 10''3 events/s going into the 2nd and 3rd level triggers. System resistance to errors is discussed. (Author) 3 refs

  17. A communication network for LHC detector readout

    International Nuclear Information System (INIS)

    Romero, L.

    1993-01-01

    This paper describe a network architecture for data taking in LHC environment. The network is composed of 64 rings of point to point links working at 100 Mbytes/s. The network connect the front end electronics, computer farms and two data switches. The efficiency of the system is discussed. Using extracted 1 kbyte events for the 2nd level trigger and whole 1 Mbyte events for the 3rd level trigger, then the system can sustain working rates of 2 x 10''5 and 2 x 10''3events/s going into the 2nd and 3rd level triggers. System resistance to errors is discussed. (Author)

  18. Operations of the reconfigured Ground Communications Facility Central Communications Terminal and the Network Operations Control Center

    Science.gov (United States)

    Santana, J. C.; Jennings, L. E.

    1982-01-01

    The ground communications facility (GCF) central communications terminal and network operations control center (NOCC) hardware was rearranged, supplemented, and modified, and software programs changed to provide an improved GCF and NOCC operational environment and capability. Control center operations section activities required to make the changeover from the old to the new GCF and NOCC configuration are addressed.

  19. 76 FR 23812 - Reliability and Continuity of Communications Networks, Including Broadband Technologies; Effects...

    Science.gov (United States)

    2011-04-28

    ...] Reliability and Continuity of Communications Networks, Including Broadband Technologies; Effects on Broadband...: Effects on Broadband Communications Networks of Damage or Failure of Network Equipment or Severe Overload... Docket 10-92 (Effects on Broadband Communications Networks of Damage or Failure of Network Equipment or...

  20. Network Coding Protocols for Smart Grid Communications

    DEFF Research Database (Denmark)

    Prior, Rui; Roetter, Daniel Enrique Lucani; Phulpin, Yannick

    2014-01-01

    but then switches to a denser coding structure towards the end. Our systematic mechanism maintains the sparse structure during the recombination of packets at the intermediate nodes. The performance of our protocol is compared by means of simulations of IEEE reference grids against standard master-slave protocols...... used in real systems. Our results show that network coding achieves 100% reliability, even for hostile network conditions, while gathering data 10 times faster than standard master-slave schemes....

  1. Ninth International Conference on Wireless Communication and Sensor Networks

    CERN Document Server

    Tiwari, Murlidhar; Arora, Anish

    2014-01-01

    Wireless communication and sensor networks would form the backbone to create pervasive and ubiquitous environments that would have profound influence on the society and thus are important to the society. The wireless communication technologies and wireless sensor networks would encompass a wide range of domains such as HW devices such as motes, sensors and associated instrumentation, actuators, transmitters, receivers, antennas, etc., sensor network aspects such as topologies, routing algorithms, integration of heterogeneous network elements and topologies, designing RF devices and systems for energy efficiency and reliability etc. These sensor networks would provide opportunity to continuously and in a distributed manner monitor the environment and generate the necessary warnings and actions. However most of the developments have been demonstrated only in controlled and laboratory environments. So we are yet to see those powerful, ubiquitous applications for the benefit of the society. The conference and con...

  2. Overlapping coalition formation games in wireless communication networks

    CERN Document Server

    Wang, Tianyu; Saad, Walid; Han, Zhu

    2017-01-01

    This brief introduces overlapping coalition formation games (OCF games), a novel mathematical framework from cooperative game theory that can be used to model, design and analyze cooperative scenarios in future wireless communication networks. The concepts of OCF games are explained, and several algorithmic aspects are studied. In addition, several major application scenarios are discussed. These applications are drawn from a variety of fields that include radio resource allocation in dense wireless networks, cooperative spectrum sensing for cognitive radio networks, and resource management for crowd sourcing. For each application, the use of OCF games is discussed in detail in order to show how this framework can be used to solve relevant wireless networking problems. Overlapping Coalition Formation Games in Wireless Communication Networks provides researchers, students and practitioners with a concise overview of existing works in this emerging area, exploring the relevant fundamental theories, key techniqu...

  3. Perception of Communication Network Fraud Dynamics by Network ...

    African Journals Online (AJOL)

    In considering the implications of the varied nature of the potential targets, the paper identifies the view to develop effective intelligence analysis methodologies for network fraud detection and prevention by network administrators and stakeholders. The paper further notes that organizations are fighting an increasingly ...

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

    Science.gov (United States)

    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.

  5. The Vital Network: An Algorithmic Milieu of Communication and Control

    Directory of Open Access Journals (Sweden)

    Sandra Robinson

    2016-09-01

    Full Text Available The biological turn in computing has influenced the development of algorithmic control and what I call the vital network: a dynamic, relational, and generative assemblage that is self-organizing in response to the heterogeneity of contemporary network processes, connections, and communication. I discuss this biological turn in computation and control for communication alongside historically significant developments in cybernetics that set out the foundation for the development of self-regulating computer systems. Control is shifting away from models that historically relied on the human-animal model of cognition to govern communication and control, as in early cybernetics and computer science, to a decentred, nonhuman model of control by algorithm for communication and networks. To illustrate the rise of contemporary algorithmic control, I outline a particular example, that of the biologically-inspired routing algorithm known as a ‘quorum sensing’ algorithm. The increasing expansion of algorithms as a sense-making apparatus is important in the context of social media, but also in the subsystems that coordinate networked flows of information. In that domain, algorithms are not inferring categories of identity, sociality, and practice associated with Internet consumers, rather, these algorithms are designed to act on information flows as they are transmitted along the network. The development of autonomous control realized through the power of the algorithm to monitor, sort, organize, determine, and transmit communication is the form of control emerging as a postscript to Gilles Deleuze’s ‘postscript on societies of control.’

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

    Science.gov (United States)

    Wolff, Richard S.; Pinck, Deborah

    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.

  7. Hierarchical Communication Network Architectures for Offshore Wind Power Farms

    Directory of Open Access Journals (Sweden)

    Mohamed A. Ahmed

    2014-05-01

    Full Text Available Nowadays, large-scale wind power farms (WPFs bring new challenges for both electric systems and communication networks. Communication networks are an essential part of WPFs because they provide real-time control and monitoring of wind turbines from a remote location (local control center. However, different wind turbine applications have different requirements in terms of data volume, latency, bandwidth, QoS, etc. This paper proposes a hierarchical communication network architecture that consist of a turbine area network (TAN, farm area network (FAN, and control area network (CAN for offshore WPFs. The two types of offshore WPFs studied are small-scale WPFs close to the grid and medium-scale WPFs far from the grid. The wind turbines are modelled based on the logical nodes (LN concepts of the IEC 61400-25 standard. To keep pace with current developments in wind turbine technology, the network design takes into account the extension of the LNs for both the wind turbine foundation and meteorological measurements. The proposed hierarchical communication network is based on Switched Ethernet. Servers at the control center are used to store and process the data received from the WPF. The network architecture is modelled and evaluated via OPNET. We investigated the end-to-end (ETE delay for different WPF applications. The results are validated by comparing the amount of generated sensing data with that of received traffic at servers. The network performance is evaluated, analyzed and discussed in view of end-to-end (ETE delay for different link bandwidths.

  8. The structural role of weak and strong links in a financial market network

    Science.gov (United States)

    Garas, A.; Argyrakis, P.; Havlin, S.

    2008-05-01

    We investigate the properties of correlation based networks originating from economic complex systems, such as the network of stocks traded at the New York Stock Exchange (NYSE). The weaker links (low correlation) of the system are found to contribute to the overall connectivity of the network significantly more than the strong links (high correlation). We find that nodes connected through strong links form well defined communities. These communities are clustered together in more complex ways compared to the widely used classification according to the economic activity. We find that some companies, such as General Electric (GE), Coca Cola (KO), and others, can be involved in different communities. The communities are found to be quite stable over time. Similar results were obtained by investigating markets completely different in size and properties, such as the Athens Stock Exchange (ASE). The present method may be also useful for other networks generated through correlations.

  9. Bidirectional Quantum Secure Direct Communication Network Protocol with Hyperentanglement

    International Nuclear Information System (INIS)

    Gu Bin; Chen Yulin; Huang Yugai; Fang Xia

    2011-01-01

    We propose a bidirectional quantum secure direct communication (QSDC) network protocol with the hyperentanglment in both the spatial-mode ad the polarization degrees of freedom of photon pairs which can in principle be produced with a beta barium borate crystal. The secret message can be encoded on the photon pairs with unitary operations in these two degrees of freedom independently. Compared with other QSDC network protocols, our QSDC network protocol has a higher capacity as each photon pair can carry 4 bits of information. Also, we discuss the security of our QSDC network protocol and its feasibility with current techniques. (general)

  10. VIRTUAL NETWORK COMMUNICATION AND ITS IMPACT ON INTERPERSONAL RELATIONS

    Directory of Open Access Journals (Sweden)

    Сергей Николаевич Хуторной

    2013-08-01

    Full Text Available The Internet was playing an increasing role in human life. Increasingly popular sites, where visitors can interact with other visitors through this site. Becoming popular communication "online", partially displacing the real-мире. There arises a problem of Internet addiction, or dependence on the Internet, which includes not only the dependence on virtual communication in social networks, but also addiction to gambling, online games, electronic purchases, and so on. Virtual reality acts not only as an intermediary virtual communication, but also significantly affect the nature, means and methods of communication, which ultimately has a significant effect on identity, often negatively, transforming it. The article dedicated to the analysis  of intercourse in virtual reality. The specification of net communication in comparing of real social communication is researching. The concept of Internet addicion is examined.DOI: http://dx.doi.org/10.12731/2218-7405-2013-6-9

  11. AIDS communications through social networks: catalyst for ...

    African Journals Online (AJOL)

    ... as well as the media. Mobilising basic social communications may be a necessary resource (as much as services and finance) to scale HIV prevention and treatment to the population level. Keywords: affective behaviour change, community, sexual behaviour, social capital, survey. African Journal of AIDS Research 2004, ...

  12. An exploration of the strategic implementation of marketing communication within social networking communication context

    OpenAIRE

    Cloete, Ewoudt

    2012-01-01

    Taking into consideration the dramatic changes ushered in by the exponential growth of social networking, marketers are left without a dependable framework on how to implement social networking strategically and in alignment with other modern as well as traditional marketing disciplines. In light of this, the study aims to explore the strategic implementation of social networking within the context of a dependable marketing theoretical model, known as the marketing communications mix. D...

  13. Resource Management in Broadband Communication Networks

    DEFF Research Database (Denmark)

    Hansen, Mads Stenhuus

    2003-01-01

    at developing a demonstration platform, where software agents handled virtually all aspects of controlling an ATM-based network. In the beginning of the part about simulated ants it is explained how scientists believe ants in nature find their way through the environment between their nest and food sources...... of them with improved characteristics, and others with worse characteristics (compared to the original model). The results from the investigation of the use of software agents in the context of networks is primarily qualitative, since it was not possible to make a lot of measurements that could in reality......, that reflects the situation in a competitive telecommunication market, with several service providers sharing the same physical network. The investigation of the simulated ants, on the other hand, gives a many promising results, suggesting that they can successfully be used to solve some problems...

  14. A Communication network for LHC detector readout

    Energy Technology Data Exchange (ETDEWEB)

    Romero, L.

    1993-07-01

    This paper describe a network architecture for data taking in LHC environment. The network is composed of 64 rings of point to point links working at 100 Mbytes/s. The network connect the front end electronics, computer farms and two data switches. The efficiency of the system is discussed. Using extracted 1 Kbyte events for the 2nd level trigger and whole 1 Mbyte events for the 3rd level trigger, then the system can sustain working rates of 2 x 10''5 and 2 x 10''3 events/s going into the 2nd and 3rd level triggers. System resistance to errors is discussed. (Author) 3 refs.

  15. Future cooperative communication systems driven by social mobile networks

    DEFF Research Database (Denmark)

    Blázovics, L.; Varga, C.; Bamford, W.

    2011-01-01

    In this work we are underlining the importance of social mobile networks for upcoming cooperative communication systems. The assumption of this work is that future mobile communication systems will incorporate user cooperation, i.e. a combination of cellular access in parallel with ongoing short...... range links to the neighboring devices. It has been shown that user cooperation enables higher data rates, better spectral efficiencies, and reduces the energy consumption of the mobile unit. In this work the social mobile networks are identified to be a fertile ground to facilitate the cooperative use...... cases. By the example of the Gedda-Headz gaming community, possible links between cooperative mobile communication and social mobile networks are shown....

  16. Performances of Free-Space Optical Communication System Over Strong Turbulence

    Directory of Open Access Journals (Sweden)

    Ucuk Darusalam

    2014-08-01

    Full Text Available We report an experimental of free-space optical communication (FSOC system that use tube propagation simulator (TPS as the turbulence medium. The FSOC system usewavelength of 1550 nm at the rate transmission of 1000 Mbps and amplified with EDFA at the output of +23 dBm. Index structure of 10-15–10-13 as the representation of atmosphere index turbulences are used for simulation of intensity distribution model or scintillation. The simulation use gammagamma and K model as well. The beam wave propagation models used in simulation are plane wave, spherical wave and Gaussian wave. Spherical wave achieves highest performance via gamma-gamma in strong turbulence. While Gaussian wave achieves highest performance also via K model. We also found, characteristical FSOC system performance is calculated more accurately with gamma-gamma method for strong turbulence than K model. The performances from gamma-gamma for strong turbulenceare at 22.55 dB, at 5.33×10-4, and at 9.41 ×10-6. 

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

    Science.gov (United States)

    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.

  18. Optimizing Communication in Air Ground Robot Networks using Decentralized Control

    Science.gov (United States)

    2010-05-08

    on a team of AscTec Hum- mingbird flying quadrotor robots providing network coverage for ground vehicles, using xBee -PRO modules for wireless...an ARM micro-processor and 2.4 GHz xBee mod- ules for wireless communication, and three ground vehicles. We conducted the experiments in a room... xBee -XSC wireless modules. The tests were conducted on four ground vehicles, and three aerial communication vehicles with control param- eters λ = 1

  19. Innovation and communicative action: health management networks and technologies

    OpenAIRE

    Rivera,Francisco Javier Uribe; Artmann,Elizabeth

    2016-01-01

    Abstract: This article discusses elements of a theory of innovation from the perspective of innovation networks and social construction of technology, based on Habermas' Theory of Communicative Action and authors from the Sociology of Innovation. Based on the theoretical framework of the communicative production of scientific facts, we focus on innovation management as a basic dimension that must meet some organizational and methodological requirements in order to power its results. We presen...

  20. A Secure Communication Suite for Underwater Acoustic Sensor Networks

    Directory of Open Access Journals (Sweden)

    Angelica Lo Duca

    2012-11-01

    Full Text Available 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.

  1. Communication-Free Distributed Coverage for Networked Systems

    KAUST Repository

    Yazicioglu, A. Yasin

    2016-01-15

    In this paper, we present a communication-free algorithm for distributed coverage of an arbitrary network by a group of mobile agents with local sensing capabilities. The network is represented as a graph, and the agents are arbitrarily deployed on some nodes of the graph. Any node of the graph is covered if it is within the sensing range of at least one agent. The agents are mobile devices that aim to explore the graph and to optimize their locations in a decentralized fashion by relying only on their sensory inputs. We formulate this problem in a game theoretic setting and propose a communication-free learning algorithm for maximizing the coverage.

  2. Innovation and communicative action: health management networks and technologies

    Directory of Open Access Journals (Sweden)

    Francisco Javier Uribe Rivera

    Full Text Available Abstract: This article discusses elements of a theory of innovation from the perspective of innovation networks and social construction of technology, based on Habermas' Theory of Communicative Action and authors from the Sociology of Innovation. Based on the theoretical framework of the communicative production of scientific facts, we focus on innovation management as a basic dimension that must meet some organizational and methodological requirements in order to power its results. We present and discuss instruments such as Situational Planning, Prospective Analysis, Strategic Portfolio Management, and Networks Management that can help deal with the challenge of innovation and exploration of the future. We conclude that network organizational formats centered on reflexivity of interdisciplinary groups and planning approaches that encourage innovation criteria in assessing the attractiveness of activities and that help anticipate forms of innovation through systematic prospective analysis can potentiate the process of generating innovation as a product of networks.

  3. Underwater Optical Wireless Communications, Networking, and Localization: A Survey

    KAUST Repository

    Saeed, Nasir

    2018-02-28

    Underwater wireless communications can be carried out through acoustic, radio frequency (RF), and optical waves. Compared to its bandwidth limited acoustic and RF counterparts, underwater optical wireless communications (UOWCs) can support higher data rates at low latency levels. However, severe aquatic channel conditions (e.g., absorption, scattering, turbulence, etc.) pose great challenges for UOWCs and significantly reduce the attainable communication ranges, which necessitates efficient networking and localization solutions. Therefore, we provide a comprehensive survey on the challenges, advances, and prospects of underwater optical wireless networks (UOWNs) from a layer by layer perspective which includes: 1) Potential network architectures; 2) Physical layer issues including propagation characteristics, channel modeling, and modulation techniques 3) Data link layer problems covering link configurations, link budgets, performance metrics, and multiple access schemes; 4) Network layer topics containing relaying techniques and potential routing algorithms; 5) Transport layer subjects such as connectivity, reliability, flow and congestion control; 6) Application layer goals and state-of-the-art UOWN applications, and 7) Localization and its impacts on UOWN layers. Finally, we outline the open research challenges and point out the future directions for underwater optical wireless communications, networking, and localization research.

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

    Science.gov (United States)

    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.

  5. Mechanical Cell-Cell Communication in Fibrous Networks: The Importance of Network Geometry.

    Science.gov (United States)

    Humphries, D L; Grogan, J A; Gaffney, E A

    2017-03-01

    Cells contracting in extracellular matrix (ECM) can transmit stress over long distances, communicating their position and orientation to cells many tens of micrometres away. Such phenomena are not observed when cells are seeded on substrates with linear elastic properties, such as polyacrylamide (PA) gel. The ability for fibrous substrates to support far reaching stress and strain fields has implications for many physiological processes, while the mechanical properties of ECM are central to several pathological processes, including tumour invasion and fibrosis. Theoretical models have investigated the properties of ECM in a variety of network geometries. However, the effects of network architecture on mechanical cell-cell communication have received little attention. This work investigates the effects of geometry on network mechanics, and thus the ability for cells to communicate mechanically through different networks. Cell-derived displacement fields are quantified for various network geometries while controlling for network topology, cross-link density and micromechanical properties. We find that the heterogeneity of response, fibre alignment, and substrate displacement fields are sensitive to network choice. Further, we show that certain geometries support mechanical communication over longer distances than others. As such, we predict that the choice of network geometry is important in fundamental modelling of cell-cell interactions in fibrous substrates, as well as in experimental settings, where mechanical signalling at the cellular scale plays an important role. This work thus informs the construction of theoretical models for substrate mechanics and experimental explorations of mechanical cell-cell communication.

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

    Science.gov (United States)

    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.

  7. Tight Network Topology Dependent Bounds on Rounds of Communication

    OpenAIRE

    Chattopadhyay, Arkadev; Langberg, Michael; Li, Shi; Rudra, Atri

    2016-01-01

    We prove tight network topology dependent bounds on the round complexity of computing well studied $k$-party functions such as set disjointness and element distinctness. Unlike the usual case in the CONGEST model in distributed computing, we fix the function and then vary the underlying network topology. This complements the recent such results on total communication that have received some attention. We also present some applications to distributed graph computation problems. Our main contri...

  8. Distributed fusion estimation for sensor networks with communication constraints

    CERN Document Server

    Zhang, Wen-An; Song, Haiyu; Yu, Li

    2016-01-01

    This book systematically presents energy-efficient robust fusion estimation methods to achieve thorough and comprehensive results in the context of network-based fusion estimation. It summarizes recent findings on fusion estimation with communication constraints; several novel energy-efficient and robust design methods for dealing with energy constraints and network-induced uncertainties are presented, such as delays, packet losses, and asynchronous information... All the results are presented as algorithms, which are convenient for practical applications.

  9. Seamless and secure communications over heterogeneous wireless networks

    CERN Document Server

    Cao, Jiannong

    2014-01-01

    This brief provides an overview of the requirements, challenges, design issues and major techniques for seamless and secure communications over heterogeneous wireless networks. It summarizes and provides detailed insights into the latest research on handoff management, mobility management, fast authentication and security management to support seamless and secure roaming for mobile clients. The reader will also learn about the challenges in developing relevant technologies and providing ubiquitous Internet access over heterogeneous wireless networks. The authors have extensive experience in im

  10. GPSS and Modeling of Computer Communication Networks.

    Science.gov (United States)

    1982-04-01

    Project Manager _A SACDIN - Stragetic Air Command Digital Network * SIGMA - Name of force level maneuver control system -’ SINSCRIPT - Generic name of...SEIZE "facility" in GPSS. The SEIZE block is then a model statement that can be readily understood by managers as weil as program- mers. The majority of...1 Director, BRL Information Exchange Building 328 US Army Logistics Management Center 1 Director, BRL ATTN: DRXNC-D ATTN: DRDAR-TSB-S (STINFO Br) Fort

  11. Dichotomous Dynamics in E-I Networks with Strongly and Weakly Intra-connected Inhibitory Neurons

    Directory of Open Access Journals (Sweden)

    Scott Rich

    2017-12-01

    Full Text Available The interconnectivity between excitatory and inhibitory neural networks informs mechanisms by which rhythmic bursts of excitatory activity can be produced in the brain. One such mechanism, Pyramidal Interneuron Network Gamma (PING, relies primarily upon reciprocal connectivity between the excitatory and inhibitory networks, while also including intra-connectivity of inhibitory cells. The causal relationship between excitatory activity and the subsequent burst of inhibitory activity is of paramount importance to the mechanism and has been well studied. However, the role of the intra-connectivity of the inhibitory network, while important for PING, has not been studied in detail, as most analyses of PING simply assume that inhibitory intra-connectivity is strong enough to suppress subsequent firing following the initial inhibitory burst. In this paper we investigate the role that the strength of inhibitory intra-connectivity plays in determining the dynamics of PING-style networks. We show that networks with weak inhibitory intra-connectivity exhibit variations in burst dynamics of both the excitatory and inhibitory cells that are not obtained with strong inhibitory intra-connectivity. Networks with weak inhibitory intra-connectivity exhibit excitatory rhythmic bursts with weak excitatory-to-inhibitory synapses for which classical PING networks would show no rhythmic activity. Additionally, variations in dynamics of these networks as the excitatory-to-inhibitory synaptic weight increases illustrates the important role that consistent pattern formation in the inhibitory cells serves in maintaining organized and periodic excitatory bursts. Finally, motivated by these results and the known diversity of interneurons, we show that a PING-style network with two inhibitory subnetworks, one strongly intra-connected and one weakly intra-connected, exhibits organized and periodic excitatory activity over a larger parameter regime than networks with a

  12. perception of communication network fraud dynamics by network ...

    African Journals Online (AJOL)

    ES Obe

    extremely costly incidents of vulnerabilities, there remains a remarkable level of compla- cency on the part of .... network fraud dynamics, fraud de- tection techniques in place, changing patterns of fraudsters, in the study area, ..... test is carried out, and it is a critical fac- tor in deciding whether to accept or reject a Hypothesis.

  13. Advances and Challenges in Convergent Communication Networks

    DEFF Research Database (Denmark)

    Toral-Cruz, Homero; Mihovska, Albena

    2017-01-01

    is composed by twenty nine high quality original papers covering theoretical and practical aspects on this emerging topic in order to provide novel ideas and directions for the relevant scientific industrial and academic community. We have selected a set of best papers from: a) 15th International Conference...... Knowledge in Telecommunication Technologies and Optics (KTTO 2015); b) 22th International Conference on Computer Networks (CN 2015); and c) the academic community around the globe (for researchers who could not participate in the above mentioned conferences). All conference papers have been extended...

  14. Social Networking Among Youth and Their Communication and Conflict Resolution Skills

    Directory of Open Access Journals (Sweden)

    Mistry DR

    2014-12-01

    Full Text Available Introduction: New digital media have dramatically altered the communication landscape, especially for youth. “Indian web users spend 26 minutes online each day”. This study is concerned with effect of social networking on youth regarding potential risk, safety, wellbeing & skill development because they are still maturing & forming the ability to attain & implement communication & conflict resolution skill on interpersonal level. Aim & objective: To explore the impact of social networking on communication & conflict resolution skills among first MBBS students. Material & Methods: A cross-sectional study was carried out on 122 first year MBBS students using semi structured questionnaire after taking their consent. Data collection was based on purposive sampling. Data entry and analysis was done using excel and SPSS v16. Result: Mean age of participants was 17.7 + 0.62 years, All the participants 122 (100% have their own cell phone & 112 (91.8% were using internet. Majority of participants have their profile on Facebook 100 (81.9% and What’s app 105 (86.1%. Twenty seven percent (33 participants strongly agreed that “people who rely on social networking are losing the ability to talk with others”, while 50 (41% strongly disagreed to it. More than forty seven percent (58 of participants were of strong belief that “people cannot effectively solve problem using social networking”. More than half (52.4% of participants said that “it’s easy to take things the wrong way during social networking”. Conclusion: The study shows that participants have replaced traditional methods of communication with social networking on which they spend a fair amount of time. Use of social networking sites helped half of the adolescents to open up to the world but these sites did not help much in conflict resolution as responded by nearly half of participants.

  15. Distributed Optimal Dispatch of Distributed Energy Resources Over Lossy Communication Networks

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Junfeng; Yang, Tao; Wu, Di; Kalsi, Karanjit; Johansson, Karl Henrik

    2017-11-01

    In this paper, we consider the economic dispatch problem (EDP), where a cost function that is assumed to be strictly convex is assigned to each of distributed energy resources (DERs), over packet dropping networks. The goal of a standard EDP is to minimize the total generation cost while meeting total demand and satisfying individual generator output limit. We propose a distributed algorithm for solving the EDP over networks. The proposed algorithm is resilient against packet drops over communication links. Under the assumption that the underlying communication network is strongly connected with a positive probability and the packet drops are independent and identically distributed (i.i.d.), we show that the proposed algorithm is able to solve the EDP. Numerical simulation results are used to validate and illustrate the main results of the paper.

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

    Science.gov (United States)

    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

  17. Communication for Influence : Building ICTD Networks in Central ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    It will do so by building regional ICT for development (ICTD) research and advocacy networks in Central, East and West Africa. ... Articles de revue. Rwanda's policy vacuum could mean trouble for broadband. Évaluations. Communication for influence : linking advocacy, dissemination and research by building ICTD ...

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

    Science.gov (United States)

    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. Localization and Communication for UWB-based Wireless Sensor Networks

    NARCIS (Netherlands)

    Wang, Y.

    2011-01-01

    The great demand for location-aware wireless sensor networks (WSNs) motivates the research in this thesis. The unique characteristics of WSNs impose numerous challenges on localization and communication. In this thesis, we handle some key challenges and provide affordable solutions. Impulse radio

  20. Role of Communication Networks in Behavioral Systems Analysis

    Science.gov (United States)

    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…

  1. Communication, Social Networks, and Influence in Citizen Participation.

    Science.gov (United States)

    Gaunt, Thomas P.

    1998-01-01

    Interviews and surveys of participants in five community projects investigated whether the communication process for citizen participation is a factor in increasing or decreasing citizen influence in decision making for a project. Findings demonstrate the importance of social-network analysis in assessing the effectiveness of participation…

  2. Smart Control of Energy Distribution Grids over Heterogeneous Communication Networks

    DEFF Research Database (Denmark)

    Schwefel, Hans-Peter; Silva, Nuno; Olsen, Rasmus Løvenstein

    2018-01-01

    behavior needs to be analyzed within the full system context. This paper considers two prominent families of wireless communication technologies: cellular 2G to 4G systems and IEEE 802.11 WiFi. Selected results on network performance and its impact on two distribution system control use-cases are presented...

  3. Communication for Influence : Building ICTD Networks in Central ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    This project seeks to help achieve universal affordable access to broadband information and communication technology (ICT) infrastructure in a number of countries on the East and West coasts of Africa. It will do so by building regional ICT for development (ICTD) research and advocacy networks in Central, East and West ...

  4. Test experience on an ultrareliable computer communication network

    Science.gov (United States)

    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.

  5. Optimal Planning of Communication System of CPS for Distribution Network

    Directory of Open Access Journals (Sweden)

    Ting Yang

    2017-01-01

    Full Text Available IoT is the technical basis to realize the CPS (Cyber Physical System for distribution networks, with which the complex system becomes more intelligent and controllable. Because of the multihop and self-organization characteristics, the large-scale heterogeneous CPS network becomes more difficult to plan. Using topological potential theory, one of typical big data analysis technologies, this paper proposed a novel optimal CPS planning model. Topological potential equalization is considered as the optimization objective function in heterogeneous CPS network with the constraints of communication requirements, physical infrastructures, and network reliability. An improved binary particle swarm optimization algorithm is proposed to solve this complex optimal problem. Two IEEE classic examples are adopted in the simulation, and the results show that, compared with benchmark algorithms, our proposed method can provide an effective topology optimization scheme to improve the network reliability and transmitting performance.

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

    Science.gov (United States)

    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.

  7. Persian Linguistic and Rhetorical Pathology in The Telegram Communication Network

    Directory of Open Access Journals (Sweden)

    M. Hedayat Mofidi

    2017-12-01

    Full Text Available Today, the mobile phone, with its wide range of features, is an inexpensive, easy to use, and most modern communication tool. One of the special applications of smart phones is providing spaces and facilities such as SMS services, virtual networks, and interactive groups that link people and groups from different linguistic and cultural background. In this paper, we tried to study the messages of the Farsi-speaking users of the Telegram communication network from the linguistics perspective. In this regard, the linguistics and rhetorical correspondence of short messages in Persian language was studied by the content-analysis method. The statistical population consisted of 150 messages which contained 327 sentences. These messages were randomly selected from 5 different groups. Persian language used in cyberspace differs from standard Persian language. The first step in correcting communication language errors in cyberspace is to inform the users about the type of errors.

  8. Accepting Hybrid Networks of Evolutionary Processors with Special Topologies and Small Communication

    OpenAIRE

    Jürgen Dassow; Florin Manea

    2010-01-01

    Starting from the fact that complete Accepting Hybrid Networks of Evolutionary Processors allow much communication between the nodes and are far from network structures used in practice, we propose in this paper three network topologies that restrict the communication: star networks, ring networks, and grid networks. We show that ring-AHNEPs can simulate 2-tag systems, thus we deduce the existence of a universal ring-AHNEP. For star networks or grid networks, we show a more general result; th...

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  12. Link and Network Layers Design for Ultra-High-Speed Terahertz-Band Communications Networks

    Science.gov (United States)

    2017-01-01

    has hampered the use of the THz band for any application beyond sensing. However, many recent advancements with dierent technologies is finally...addition, the University at Bualo is currently preparing a US Patent Application for this invention. • Graphene-based Plasmonic Nano -antenna Arrays (Sec...networks [29] or the Internet of Nano -Things [34]. In this context, the development of a new communication and networking technology to support networks with

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

    Science.gov (United States)

    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.

  14. Simulation of Routing Protocol with CoS/QoS Enhancements in Heterogeneous Communication Network

    National Research Council Canada - National Science Library

    Kubera, Emil; Sliwa, Joanna; Zubel, Krzysztof; Mroczko, Adrian

    2006-01-01

    The article describes the subject of QoS routing mechanism in tactical heterogeneous communication network consisting of network elements built in different technologies and connected following rules...

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

    Science.gov (United States)

    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.

  16. Utilization of Selected Data Mining Methods for Communication Network Analysis

    Directory of Open Access Journals (Sweden)

    V. Ondryhal

    2011-06-01

    Full Text Available The aim of the project was to analyze the behavior of military communication networks based on work with real data collected continuously since 2005. With regard to the nature and amount of the data, data mining methods were selected for the purpose of analyses and experiments. The quality of real data is often insufficient for an immediate analysis. The article presents the data cleaning operations which have been carried out with the aim to improve the input data sample to obtain reliable models. Gradually, by means of properly chosen SW, network models were developed to verify generally valid patterns of network behavior as a bulk service. Furthermore, unlike the commercially available communication networks simulators, the models designed allowed us to capture nonstandard models of network behavior under an increased load, verify the correct sizing of the network to the increased load, and thus test its reliability. Finally, based on previous experience, the models enabled us to predict emergency situations with a reasonable accuracy.

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

    Science.gov (United States)

    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.

  18. Weak and strong publics: drawing on Nancy Fraser to explore parental participation in neonatal networks

    Science.gov (United States)

    Gibson, Andrew J.; Lewando‐Hundt, Gillian; Blaxter, Loraine

    2014-01-01

    Abstract Aims  We draw on the work of Nancy Fraser, and in particular her concepts of weak and strong publics, to analyze the process of parental involvement in managed neonatal network boards. Background  Public involvement has moved beyond the individual level to include greater involvement of both patients and the public in governance. However, there is relatively little literature that explores the nature and outcomes of long‐term patient involvement initiatives or has attempted to theorize, particularly at the level of corporate decision making, the process of patient and public involvement. Methods  A repeated survey of all neonatal network managers in England was carried out in 2006–07 to capture developments and changes in parental representation over this time period. This elicited information about the current status of parent representation on neonatal network boards. Four networks were also selected as case studies. This involved interviews with key members of each network board, interviews with parent representatives, observation of meetings and access to board minutes. Results  Data collected show that a wide range of approaches to involving parents has been adopted. These range from decisions not to involve parents at this level to relatively well‐developed systems designed to link parent representatives on network boards to parents in neonatal units. Conclusion  Despite these variations, we suggest that parental participation within neonatal services remains an example of a weak public because the parent representatives had limited participation with little influence on decision making. PMID:22040481

  19. Image processing with a cellular nonlinear network [rapid communication

    Science.gov (United States)

    Morfu, S.

    2005-08-01

    A cellular nonlinear network (CNN) based on uncoupled nonlinear oscillators is proposed for image processing purposes. It is shown theoretically and numerically that the contrast of an image loaded at the nodes of the CNN is strongly enhanced, even if this one is initially weak. An image inversion can be also obtained without reconfiguration of the network whereas a gray levels extraction can be performed with an additional threshold filtering. Lastly, an electronic implementation of this CNN is presented.

  20. The Quake-Catcher Network: Improving Earthquake Strong Motion Observations Through Community Engagement

    Science.gov (United States)

    Cochran, E. S.; Lawrence, J. F.; Christensen, C. M.; Chung, A. I.; Neighbors, C.; Saltzman, J.

    2010-12-01

    The Quake-Catcher Network (QCN) involves the community in strong motion data collection by utilizing volunteer computing techniques and low-cost MEMS accelerometers. Volunteer computing provides a mechanism to expand strong-motion seismology with minimal infrastructure costs, while promoting community participation in science. Micro-Electro-Mechanical Systems (MEMS) triaxial accelerometers can be attached to a desktop computer via USB and are internal to many laptops. Preliminary shake table tests show the MEMS accelerometers can record high-quality seismic data with instrument response similar to research-grade strong-motion sensors. QCN began distributing sensors and software to K-12 schools and the general public in April 2008 and has grown to roughly 1500 stations worldwide. We also recently tested whether sensors could be quickly deployed as part of a Rapid Aftershock Mobilization Program (RAMP) following the 2010 M8.8 Maule, Chile earthquake. Volunteers are recruited through media reports, web-based sensor request forms, as well as social networking sites. Using data collected to date, we examine whether a distributed sensing network can provide valuable seismic data for earthquake detection and characterization while promoting community participation in earthquake science. We utilize client-side triggering algorithms to determine when significant ground shaking occurs and this metadata is sent to the main QCN server. On average, trigger metadata are received within 1-10 seconds from the observation of a trigger; the larger data latencies are correlated with greater server-station distances. When triggers are detected, we determine if the triggers correlate to others in the network using spatial and temporal clustering of incoming trigger information. If a minimum number of triggers are detected then a QCN-event is declared and an initial earthquake location and magnitude is estimated. Initial analysis suggests that the estimated locations and magnitudes are

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

    Science.gov (United States)

    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.

  2. Architecture for Cognitive Networking within NASAs Future Space Communications Infrastructure

    Science.gov (United States)

    Clark, Gilbert J., III; Eddy, Wesley M.; Johnson, Sandra K.; Barnes, James; Brooks, David

    2016-01-01

    Future space mission concepts and designs pose many networking challenges for command, telemetry, and science data applications with diverse end-to-end data delivery needs. For future end-to-end architecture designs, a key challenge is meeting expected application quality of service requirements for multiple simultaneous mission data flows with options to use diverse onboard local data buses, commercial ground networks, and multiple satellite relay constellations in LEO, MEO, GEO, or even deep space relay links. Effectively utilizing a complex network topology requires orchestration and direction that spans the many discrete, individually addressable computer systems, which cause them to act in concert to achieve the overall network goals. The system must be intelligent enough to not only function under nominal conditions, but also adapt to unexpected situations, and reorganize or adapt to perform roles not originally intended for the system or explicitly programmed. This paper describes architecture features of cognitive networking within the future NASA space communications infrastructure, and interacting with the legacy systems and infrastructure in the meantime. The paper begins by discussing the need for increased automation, including inter-system collaboration. This discussion motivates the features of an architecture including cognitive networking for future missions and relays, interoperating with both existing endpoint-based networking models and emerging information-centric models. From this basis, we discuss progress on a proof-of-concept implementation of this architecture as a cognitive networking on-orbit application on the SCaN Testbed attached to the International Space Station.

  3. Architecture for Cognitive Networking within NASA's Future Space Communications Infrastructure

    Science.gov (United States)

    Clark, Gilbert; Eddy, Wesley M.; Johnson, Sandra K.; Barnes, James; Brooks, David

    2016-01-01

    Future space mission concepts and designs pose many networking challenges for command, telemetry, and science data applications with diverse end-to-end data delivery needs. For future end-to-end architecture designs, a key challenge is meeting expected application quality of service requirements for multiple simultaneous mission data flows with options to use diverse onboard local data buses, commercial ground networks, and multiple satellite relay constellations in LEO, GEO, MEO, or even deep space relay links. Effectively utilizing a complex network topology requires orchestration and direction that spans the many discrete, individually addressable computer systems, which cause them to act in concert to achieve the overall network goals. The system must be intelligent enough to not only function under nominal conditions, but also adapt to unexpected situations, and reorganize or adapt to perform roles not originally intended for the system or explicitly programmed. This paper describes an architecture enabling the development and deployment of cognitive networking capabilities into the envisioned future NASA space communications infrastructure. We begin by discussing the need for increased automation, including inter-system discovery and collaboration. This discussion frames the requirements for an architecture supporting cognitive networking for future missions and relays, including both existing endpoint-based networking models and emerging information-centric models. From this basis, we discuss progress on a proof-of-concept implementation of this architecture, and results of implementation and initial testing of a cognitive networking on-orbit application on the SCaN Testbed attached to the International Space Station.

  4. Distributed wireless quantum communication networks with partially entangled pairs

    International Nuclear Information System (INIS)

    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. (general)

  5. Network Communication as a Service-Oriented Capability

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. Structural changes in data communication in wireless sensor networks

    Science.gov (United States)

    da Silva Cabral, Raquel; Aquino, Andre L. L.; Frery, Alejandro C.; Rosso, Osvaldo A.; Ramírez, Jaime A.

    2013-12-01

    Wireless sensor networks are an important technology for making distributed autonomous measures in hostile or inaccessible environments. Among the challenges they pose, the way data travel among them is a relevant issue since their structure is quite dynamic. The operational topology of such devices can often be described by complex networks. In this work, we assess the variation of measures commonly employed in the complex networks literature applied to wireless sensor networks. Four data communication strategies were considered: geometric, random, small-world, and scale-free models, along with the shortest path length measure. The sensitivity of this measure was analyzed with respect to the following perturbations: insertion and removal of nodes in the geometric strategy; and insertion, removal and rewiring of links in the other models. The assessment was performed using the normalized Kullback-Leibler divergence and Hellinger distance quantifiers, both deriving from the Information Theory framework. The results reveal that the shortest path length is sensitive to perturbations.

  7. Capacity of Wireless Ad Hoc Networks with Opportunistic Collaborative Communications

    Directory of Open Access Journals (Sweden)

    Simeone O

    2007-01-01

    Full Text Available Optimal multihop routing in ad hoc networks requires the exchange of control messages at the MAC and network layer in order to set up the (centralized optimization problem. Distributed opportunistic space-time collaboration (OST is a valid alternative that avoids this drawback by enabling opportunistic cooperation with the source at the physical layer. In this paper, the performance of OST is investigated. It is shown analytically that opportunistic collaboration outperforms (centralized optimal multihop in case spatial reuse (i.e., the simultaneous transmission of more than one data stream is not allowed by the transmission protocol. Conversely, in case spatial reuse is possible, the relative performance between the two protocols has to be studied case by case in terms of the corresponding capacity regions, given the topology and the physical parameters of network at hand. Simulation results confirm that opportunistic collaborative communication is a promising paradigm for wireless ad hoc networks that deserves further investigation.

  8. A reference model for the development of networked organizational communication: A communication perspective.

    NARCIS (Netherlands)

    de Vries, Sjoerd A.; Isaias, P.

    2002-01-01

    Organizational communication is increasingly based on electronic networks. The growth is seldom the result of a planned organizational development of these technologies, but mostly driven by 'rapid' technology developments and best user practices. To enable organizations to understand and to steer

  9. Dense wavelength multiplexing of 1550 nm QKD with strong classical channels in reconfigurable networking environments

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, Danna [Los Alamos National Laboratory; Peterson, Charles G [Los Alamos National Laboratory; Dallmann, Nicholas [Los Alamos National Laboratory; Hughes, Richard J [Los Alamos National Laboratory; Mccabe, Kevin P [Los Alamos National Laboratory; Nordholt, Jane E [Los Alamos National Laboratory; Tyagi, Hush T [Los Alamos National Laboratory; Peters, Nicholas A [TELCORDIA TECHNOLOGIES; Toliver, Paul [TELCORDIA TECHNOLOGIES; Chapman, Thomas E [TELCORDIA TECHNOLOGIES; Runser, Robert J [TELCORDIA TECHNOLOGIES; Mcnown, Scott R [TELCORDIA TECHNOLOGIES

    2008-01-01

    To move beyond dedicated links and networks, quantum communications signals must be integrated into networks carrying classical optical channels at power levels many orders of magnitude higher than the quantum signals themselves. We demonstrate transmission of a 1550-nm quantum channel with up to two simultaneous 200-GHz spaced classical telecom channels, using ROADM (reconfigurable optical <1dd drop multiplexer) technology for multiplexing and routing quantum and classical signals. The quantum channel is used to perform quantum key distribution (QKD) in the presence of noise generated as a by-product of the co-propagation of classical channels. We demonstrate that the dominant noise mechanism can arise from either four-wave mixing or spontaneous Raman scattering, depending on the optical path characteristics as well <1S the classical channel parameters. We quantity these impairments and discuss mitigation strategies.

  10. High-Throughput Network Communication with NetIO

    CERN Document Server

    Schumacher, J\\"orn; The ATLAS collaboration; Vandelli, Wainer

    2016-01-01

    HPC network technologies like Infiniband, TrueScale or OmniPath provide low-latency and high-throughput communication between hosts, which makes them attractive options for data-acquisition systems in large-scale high-energy physics experiments. Like HPC networks, DAQ networks are local and include a well specified number of systems. Unfortunately traditional network communication APIs for HPC clusters like MPI or PGAS target exclusively the HPC community and are not suited well for DAQ applications. It is possible to build distributed DAQ applications using low-level system APIs like Infiniband Verbs (and this has been done), but it requires a non negligible effort and expert knowledge. On the other hand, message services like 0MQ have gained popularity in the HEP community. Such APIs allow to build distributed applications with a high-level approach and provide good performance. Unfortunately their usage usually limits developers to TCP/IP-based networks. While it is possible to operate a TCP/IP stack on to...

  11. Methods for inferring health-related social networks among coworkers from online communication patterns.

    Science.gov (United States)

    Matthews, Luke J; DeWan, Peter; Rula, Elizabeth Y

    2013-01-01

    Studies of social networks, mapped using self-reported contacts, have demonstrated the strong influence of social connections on the propensity for individuals to adopt or maintain healthy behaviors and on their likelihood to adopt health risks such as obesity. Social network analysis may prove useful for businesses and organizations that wish to improve the health of their populations by identifying key network positions. Health traits have been shown to correlate across friendship ties, but evaluating network effects in large coworker populations presents the challenge of obtaining sufficiently comprehensive network data. The purpose of this study was to evaluate methods for using online communication data to generate comprehensive network maps that reproduce the health-associated properties of an offline social network. In this study, we examined three techniques for inferring social relationships from email traffic data in an employee population using thresholds based on: (1) the absolute number of emails exchanged, (2) logistic regression probability of an offline relationship, and (3) the highest ranked email exchange partners. As a model of the offline social network in the same population, a network map was created using social ties reported in a survey instrument. The email networks were evaluated based on the proportion of survey ties captured, comparisons of common network metrics, and autocorrelation of body mass index (BMI) across social ties. Results demonstrated that logistic regression predicted the greatest proportion of offline social ties, thresholding on number of emails exchanged produced the best match to offline network metrics, and ranked email partners demonstrated the strongest autocorrelation of BMI. Since each method had unique strengths, researchers should choose a method based on the aspects of offline behavior of interest. Ranked email partners may be particularly useful for purposes related to health traits in a social network.

  12. Practical issues in picture archiving and communication system and networking

    Directory of Open Access Journals (Sweden)

    Kalyanpur Arjun

    2010-01-01

    Full Text Available Picture Archiving and Communication System (PACS is a key workflow tool in the functioning of radiology departments worldwide, today, and its utilization is rapidly growing in India. The key challenges in PACS implementation are related to vendor and feature selection, integration with the existing HIS, user training, maintenance and scalability to meet increasing demands. Additionally, the networking requirements that PACS imposes on hospital networks are not insignificant. This article attempts to review these issues from the standpoint of what a prospective or new user needs to know.

  13. ECS: Efficient Communication Scheduling for Underwater Sensor Networks

    Directory of Open Access Journals (Sweden)

    Lu Hong

    2011-03-01

    Full Text Available TDMA protocols have attracted a lot of attention for underwater acoustic sensor networks (UWSNs, because of the unique characteristics of acoustic signal propagation such as great energy consumption in transmission, long propagation delay and long communication range. Previous TDMA protocols all allocated transmission time to nodes based on discrete time slots. This paper proposes an efficient continuous time scheduling TDMA protocol (ECS for UWSNs, including the continuous time based and sender oriented conflict analysis model, the transmission moment allocation algorithm and the distributed topology maintenance algorithm. Simulation results confirm that ECS improves network throughput by 20% on average, compared to existing MAC protocols.

  14. Radio propagation and adaptive antennas for wireless communication networks

    CERN Document Server

    Blaunstein, Nathan

    2014-01-01

    Explores novel wireless networks beyond 3G, and advanced 4G technologies, such as MIMO, via propagation phenomena and the fundamentals of adapted antenna usage.Explains how adaptive antennas can improve GoS and QoS for any wireless channel, with specific examples and applications in land, aircraft and satellite communications.Introduces new stochastic approach based on several multi-parametric models describing various terrestrial scenarios, which have been experimentally verified in different environmental conditionsNew chapters on fundamentals of wireless networks, cellular and non-cellular,

  15. Stochastic network optimization with application to communication and queueing systems

    CERN Document Server

    Neely, Michael

    2010-01-01

    This text presents a modern theory of analysis, control, and optimization for dynamic networks. Mathematical techniques of Lyapunov drift and Lyapunov optimization are developed and shown to enable constrained optimization of time averages in general stochastic systems. The focus is on communication and queueing systems, including wireless networks with time-varying channels, mobility, and randomly arriving traffic. A simple drift-plus-penalty framework is used to optimize time averages such as throughput, throughput-utility, power, and distortion. Explicit performance-delay tradeoffs are prov

  16. Network secure communications based on beam halo-chaos

    International Nuclear Information System (INIS)

    Liu Qiang; Fang Jinqing; Li Yong

    2010-01-01

    Based on beam halo-chaos synchronization in the beam transport network (line)with small-world effect, using three synchronization methods:the driver-response synchronization, small-world topology coupling synchronization and multi-local small-world topology coupling synchronization, three kinds of secure communication projects were designed respectively, and were studied numerically by the Simulink tool of the Matlab software. Numerical experimental results demonstrate that encryption and decryption of the original signal are realized successfully. It provides effective theoretical foundation and reference for the next engineering design and network experiment. (authors)

  17. Uncertainties in Parameters Estimated with Neural Networks: Application to Strong Gravitational Lensing

    Science.gov (United States)

    Perreault Levasseur, Laurence; Hezaveh, Yashar D.; Wechsler, Risa H.

    2017-11-01

    In Hezaveh et al. we showed that deep learning can be used for model parameter estimation and trained convolutional neural networks to determine the parameters of strong gravitational-lensing systems. Here we demonstrate a method for obtaining the uncertainties of these parameters. We review the framework of variational inference to obtain approximate posteriors of Bayesian neural networks and apply it to a network trained to estimate the parameters of the Singular Isothermal Ellipsoid plus external shear and total flux magnification. We show that the method can capture the uncertainties due to different levels of noise in the input data, as well as training and architecture-related errors made by the network. To evaluate the accuracy of the resulting uncertainties, we calculate the coverage probabilities of marginalized distributions for each lensing parameter. By tuning a single variational parameter, the dropout rate, we obtain coverage probabilities approximately equal to the confidence levels for which they were calculated, resulting in accurate and precise uncertainty estimates. Our results suggest that the application of approximate Bayesian neural networks to astrophysical modeling problems can be a fast alternative to Monte Carlo Markov Chains, allowing orders of magnitude improvement in speed.

  18. The construction of corporate social responsibility in network societies: A communication view

    NARCIS (Netherlands)

    Schultz, F.; Castello, I.; Morsing, M.

    2013-01-01

    The paper introduces the communication view on Corporate Social Responsibility (CSR), which regards CSR as communicatively constructed in dynamic interaction processes in today's networked societies. Building on the idea that communication constitutes organizations we discuss the potentially

  19. Gigabit Satellite Network for NASA's Advanced Communication Technology Satellite (ACTS)

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  1. Asymmetries in commitment in an avian communication network.

    Science.gov (United States)

    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.

  2. Modeling and Analysis of Mobility Management in Mobile Communication Networks

    Directory of Open Access Journals (Sweden)

    Woon Min Baek

    2014-01-01

    Full Text Available 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.

  3. Analysis of NASA communications (Nascom) II network protocols and performance

    Science.gov (United States)

    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.

  4. Asymmetries in commitment in an avian communication network

    Science.gov (United States)

    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.

  5. Successive lag synchronization on dynamical networks with communication delay

    Science.gov (United States)

    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.

  6. Influence of wind speed on free space optical communication performance for Gaussian beam propagation through non Kolmogorov strong turbulence

    International Nuclear Information System (INIS)

    Deng Peng; Yuan Xiuhua; Zeng Yanan; Zhao Ming; Luo Hanjun

    2011-01-01

    In free-space optical communication links, atmospheric turbulence causes fluctuations in both the intensity and the phase of the received signal, affecting link performance. Most theoretical treatments have been described by Kolmogorov's power spectral density model through weak turbulence with constant wind speed. However, several experiments showed that Kolmogorov theory is sometimes incomplete to describe atmospheric turbulence properly, especially through the strong turbulence with variable wind speed, which is known to contribute significantly to the turbulence in the atmosphere. We present an optical turbulence model that incorporates into variable wind speed instead of constant value, a non-Kolmogorov power spectrum that uses a generalized exponent instead of constant standard exponent value 11/3, and a generalized amplitude factor instead of constant value 0.033. The free space optical communication performance for a Gaussian beam wave of scintillation index, mean signal-to-noise ratio , and mean bit error rate , have been derived by extended Rytov theory in non-Kolmogorov strong turbulence. And then the influence of wind speed variations on free space optical communication performance has been analyzed under different atmospheric turbulence intensities. The results suggest that the effects of wind speed variation through non-Kolmogorov turbulence on communication performance are more severe in many situations and need to be taken into account in free space optical communication. It is anticipated that this work is helpful to the investigations of free space optical communication performance considering wind speed under severe weather condition in the strong atmospheric turbulence.

  7. Analyzing the Dynamics of Communication in Online Social Networks

    Science.gov (United States)

    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

  8. Role of information and communication networks in malaria survival

    Directory of Open Access Journals (Sweden)

    Marathe Achla

    2007-10-01

    Full Text Available Abstract Background Quite often symptoms of malaria go unrecognized or untreated. According to the Multilateral Initiative on Malaria, 70% of the malaria cases that are treated at home are mismanaged. Up to 82% of all malaria episodes in sub-Saharan Africa are treated outside the formal health sector. Fast and appropriate diagnosis and treatment of malaria is extremely important in reducing morbidity and mortality. Method Data from 70 different countries is pooled together to construct a panel dataset of health and socio-economic variables for a time span of (1960–2004. The generalized two-stage least squares and panel data models are used to investigate the impact of information and communication network (ICN variables on malaria death probability. The intensity of ICN is represented by the number of telephone main lines per 1,000 people and the number of television sets per 1,000 people. Results The major finding is that the intensity of ICN is associated with reduced probability of deaths of people that are clinically identified as malaria infected. The results are robust for both indicators i.e. interpersonal and mass communication networks and for all model specifications examined. Conclusion The results suggest that information and communication networks can substantially scale up the effectiveness of the existing resources for malaria prevention. Resources spent in preventing malaria are far less than needed. Expanded information and communication networks will widen the avenues for community based "participatory development", that encourages the use of local information, knowledge and decision making. Timely information, immediate care and collective knowledge based treatment can be extremely important in reducing child mortality and achieving the millennium development goal.

  9. Politecast - a new communication primitive for wireless sensor networks

    OpenAIRE

    Lundén, Marcus

    2010-01-01

    Wireless sensor networks have the potential for becoming a huge market. Ericsson predicts 50 billion devices interconnected to the Internet by the year 2020. Before that, the devices must be made to be able to withstand years of usage without having to change power source as that would be too costly. These devices are typically small, inexpensive and severally resource constrained. Communication is mainly wireless, and the wireless transceiver on the node is typically the most power hungry co...

  10. Experience on the FMS Communication module Development for an Application to Safety- Critical Communication Network

    International Nuclear Information System (INIS)

    Son, Kwang Seop; Lee, Jang Soo; Kim, Jung Heon

    2009-01-01

    The field bus has been developed for a network system which supports the real-time communication of various controls and automation equipment. It is known for Profibus in the field of a production automation environment. The Profibus standard uses open communication based on the ISO/OSI model. The Probibus standard uses layer 1, layer 2, layer 7. Layer 7 of Probibus FMS(Fieldbus Message Specification) provides a information and the user of a station. The high-level communication of the safety-grade PLC (POSAFE-Q) developed through the KNICS(Korea Nuclear I and C System) project is the FMS This paper describes the design, the configuration, and the test method of the FMS communication module

  11. Analysis of a large-scale weighted network of one-to-one human communication

    Energy Technology Data Exchange (ETDEWEB)

    Onnela, Jukka-Pekka [Laboratory of Computational Engineering, Helsinki University of Technology (Finland); Saramaeki, Jari [Laboratory of Computational Engineering, Helsinki University of Technology (Finland); Hyvoenen, Joerkki [Laboratory of Computational Engineering, Helsinki University of Technology (Finland); Szabo, Gabor [Department of Physdics and Center for Complex Networks Research, University of Notre Dame, IN (United States); Menezes, M Argollo de [Department of Physdics and Center for Complex Networks Research, University of Notre Dame, IN (United States); Kaski, Kimmo [Laboratory of Computational Engineering, Helsinki University of Technology (Finland); Barabasi, Albert-Laszlo [Department of Physdics and Center for Complex Networks Research, University of Notre Dame, IN (United States); Kertesz, Janos [Laboratory of Computational Engineering, Helsinki University of Technology (Finland)

    2007-06-15

    We construct a connected network of 3.9 million nodes from mobile phone call records, which can be regarded as a proxy for the underlying human communication network at the societal level. We assign two weights on each edge to reflect the strength of social interaction, which are the aggregate call duration and the cumulative number of calls placed between the individuals over a period of 18 weeks. We present a detailed analysis of this weighted network by examining its degree, strength, and weight distributions, as well as its topological assortativity and weighted assortativity, clustering and weighted clustering, together with correlations between these quantities. We give an account of motif intensity and coherence distributions and compare them to a randomized reference system. We also use the concept of link overlap to measure the number of common neighbours any two adjacent nodes have, which serves as a useful local measure for identifying the interconnectedness of communities. We report a positive correlation between the overlap and weight of a link, thus providing strong quantitative evidence for the weak ties hypothesis, a central concept in social network analysis. The percolation properties of the network are found to depend on the type and order of removed links, and they can help understand how the local structure of the network manifests itself at the global level. We hope that our results will contribute to modelling weighted large-scale social networks, and believe that the systematic approach followed here can be adopted to study other weighted networks.

  12. Analysis of a large-scale weighted network of one-to-one human communication

    International Nuclear Information System (INIS)

    Onnela, Jukka-Pekka; Saramaeki, Jari; Hyvoenen, Joerkki; Szabo, Gabor; Menezes, M Argollo de; Kaski, Kimmo; Barabasi, Albert-Laszlo; Kertesz, Janos

    2007-01-01

    We construct a connected network of 3.9 million nodes from mobile phone call records, which can be regarded as a proxy for the underlying human communication network at the societal level. We assign two weights on each edge to reflect the strength of social interaction, which are the aggregate call duration and the cumulative number of calls placed between the individuals over a period of 18 weeks. We present a detailed analysis of this weighted network by examining its degree, strength, and weight distributions, as well as its topological assortativity and weighted assortativity, clustering and weighted clustering, together with correlations between these quantities. We give an account of motif intensity and coherence distributions and compare them to a randomized reference system. We also use the concept of link overlap to measure the number of common neighbours any two adjacent nodes have, which serves as a useful local measure for identifying the interconnectedness of communities. We report a positive correlation between the overlap and weight of a link, thus providing strong quantitative evidence for the weak ties hypothesis, a central concept in social network analysis. The percolation properties of the network are found to depend on the type and order of removed links, and they can help understand how the local structure of the network manifests itself at the global level. We hope that our results will contribute to modelling weighted large-scale social networks, and believe that the systematic approach followed here can be adopted to study other weighted networks

  13. How Networked Communication Has Changed the Ways We Tell Stories

    Directory of Open Access Journals (Sweden)

    Anna Notaro

    2014-12-01

    Full Text Available In the midst of the digital revolution, we are confronted with the task of defining how media will change our lives and how we communicate with each other in the years to come. Narrative, as one of the most ancient communication tools, has undergone substantial structural changes. This paper addresses how these changes impact the way we read and write. Does the same story conveyed through different media channels signify in the same manner? In other words, what are the differences between a printed story and a digitally presented one? Have electronic reader devices altered the way stories are told and created? And how is networked communication changing the ways we tell stories?

  14. Security Policy for a Generic Space Exploration Communication Network Architecture

    Science.gov (United States)

    Ivancic, William D.; Sheehe, Charles J.; Vaden, Karl R.

    2016-01-01

    This document is one of three. It describes various security mechanisms and a security policy profile for a generic space-based communication architecture. Two other documents accompany this document- an Operations Concept (OpsCon) and a communication architecture document. The OpsCon should be read first followed by the security policy profile described by this document 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.

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

    Science.gov (United States)

    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.

    Science.gov (United States)

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

    2015-02-04

    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.

  17. Reliable and Efficient Communications in Wireless Sensor Networks

    International Nuclear Information System (INIS)

    Abdelhakim, M.M.

    2014-01-01

    Wireless sensor network (WSN) is a key technology for a wide range of military and civilian applications. Limited by the energy resources and processing capabilities of the sensor nodes, reliable and efficient communications in wireless sensor networks are challenging, especially when the sensors are deployed in hostile environments. This research aims to improve the reliability and efficiency of time-critical communications in WSNs, under both benign and hostile environments. We start with wireless sensor network with mobile access points (SENMA), where the mobile access points traverse the network to collect information from individual sensors. Due to its routing simplicity and energy efficiency, SENMA has attracted lots of attention from the research community. Here, we study reliable distributed detection in SENMA under Byzantine attacks, where some authenticated sensors are compromised to report fictitious information. The q-out-of-m rule is considered. It is popular in distributed detection and can achieve a good trade-off between the miss detection probability and the false alarm rate. However, a major limitation with this rule is that the optimal scheme parameters can only be obtained through exhaustive search. By exploiting the linear relationship between the scheme parameters and the network size, we propose simple but effective sub-optimal linear approaches. Then, for better flexibility and scalability, we derive a near-optimal closed-form solution based on the central limit theorem. It is proved that the false alarm rate of the q-out-of-m scheme diminishes exponentially as the network size increases, even if the percentage of malicious nodes remains fixed. This implies that large-scale sensor networks are more reliable under malicious attacks. To further improve the performance under time varying attacks, we propose an effective malicious node detection scheme for adaptive data fusion; the proposed scheme is analyzed using the entropy-based trust model

  18. Current flow in random resistor networks: the role of percolation in weak and strong disorder.

    Science.gov (United States)

    Wu, Zhenhua; López, Eduardo; Buldyrev, Sergey V; Braunstein, Lidia A; Havlin, Shlomo; Stanley, H Eugene

    2005-04-01

    We study the current flow paths between two edges in a random resistor network on a L X L square lattice. Each resistor has resistance e(ax) , where x is a uniformly distributed random variable and a controls the broadness of the distribution. We find that: (a) The scaled variable u identical with u congruent to L/a(nu) , where nu is the percolation connectedness exponent, fully determines the distribution of the current path length l for all values of u . For u > 1, the behavior corresponds to the weak disorder limit and l scales as l approximately L, while for u < 1 , the behavior corresponds to the strong disorder limit with l approximately L(d(opt) ), where d(opt) =1.22+/-0.01 is the optimal path exponent. (b) In the weak disorder regime, there is a length scale xi approximately a(nu), below which strong disorder and critical percolation characterize the current path.

  19. Strong authentication of remote users over insecure networks by using fingerprint-biometric and smart cards

    Science.gov (United States)

    Khan, Muhammad K.; Zhang, Jiashu

    2006-04-01

    Recently, Lee et al. and Lin-Lai proposed fingerprint-based remote user authentication schemes using smart cards. We demonstrate that their schemes are vulnerable and susceptible to the attack and have practical pitfalls. Their schemes perform only unilateral authentication (only client authentication) and there is no mutual authentication between user and remote system, so their schemes suscept from the server spoofing attack. To overcome the flaw, we present a strong remote user authentication scheme by using fingerprint-biometric and smart cards. The proposed scheme is an extended and generalized form of ElGamal's signature scheme whose security is based on discrete logarithm problem, which is not yet forged. Proposed scheme not only overcome drawbacks and problems of previous schemes, but also provide a strong authentication of remote users over insecure network. In addition, computational costs and efficiency of the proposed scheme are better than other related schemes.

  20. Space Mobile Network: A Near Earth Communications and Navigation Architecture

    Science.gov (United States)

    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

  1. Social networks as a tool for science communication and public engagement: focus on Twitter.

    Science.gov (United States)

    López-Goñi, Ignacio; Sánchez-Angulo, Manuel

    2018-02-01

    Social networks have been used to teach and engage people about the importance of science. The integration of social networks in the daily routines of faculties and scientists is strongly recommended to increase their personal brand, improve their skills, enhance their visibility, share and communicate science to society, promote scientific culture, and even as a tool for teaching and learning. Here we review the use of Twitter in science and comment on our previous experience of using this social network as a platform for a Massive Online Open Course (MOOC) in Spain and Latin America. We propose to extend this strategy to a pan-European Microbiology MOOC in the near future. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Accepting Hybrid Networks of Evolutionary Processors with Special Topologies and Small Communication

    Directory of Open Access Journals (Sweden)

    Jürgen Dassow

    2010-08-01

    Full Text Available Starting from the fact that complete Accepting Hybrid Networks of Evolutionary Processors allow much communication between the nodes and are far from network structures used in practice, we propose in this paper three network topologies that restrict the communication: star networks, ring networks, and grid networks. We show that ring-AHNEPs can simulate 2-tag systems, thus we deduce the existence of a universal ring-AHNEP. For star networks or grid networks, we show a more general result; that is, each recursively enumerable language can be accepted efficiently by a star- or grid-AHNEP. We also present bounds for the size of these star and grid networks. As a consequence we get that each recursively enumerable can be accepted by networks with at most 13 communication channels and by networks where each node communicates with at most three other nodes.

  3. Full-Duplex Communications in Large-Scale Cellular Networks

    KAUST Repository

    AlAmmouri, Ahmad

    2016-04-01

    In-band full-duplex (FD) communications have been optimistically promoted to improve the spectrum utilization and efficiency. However, the penetration of FD communications to the cellular networks domain is challenging due to the imposed uplink/downlink interference. This thesis presents a tractable framework, based on stochastic geometry, to study FD communications in multi-tier cellular networks. Particularly, we assess the FD communications effect on the network performance and quantify the associated gains. The study proves the vulnerability of the uplink to the downlink interference and shows that the improved FD rate gains harvested in the downlink (up to 97%) comes at the expense of a significant degradation in the uplink rate (up to 94%). Therefore, we propose a novel fine-grained duplexing scheme, denoted as α-duplex scheme, which allows a partial overlap between the uplink and the downlink frequency bands. We derive the required conditions to harvest rate gains from the α-duplex scheme and show its superiority to both the FD and half-duplex (HD) schemes. In particular, we show that the α-duplex scheme provides a simultaneous improvement of 28% for the downlink rate and 56% for the uplink rate. We also show that the amount of the overlap can be optimized based on the network design objective. Moreover, backward compatibility is an essential ingredient for the success of new technologies. In the context of in-band FD communication, FD base stations (BSs) should support HD users\\' equipment (UEs) without sacrificing the foreseen FD gains. The results show that FD-UEs are not necessarily required to harvest rate gains from FD-BSs. In particular, the results show that adding FD-UEs to FD-BSs offers a maximum of 5% rate gain over FD-BSs and HD-UEs case, which is a marginal gain compared to the burden required to implement FD transceivers at the UEs\\' side. To this end, we shed light on practical scenarios where HD-UEs operation with FD-BSs outperforms the

  4. Strategies for Power Line Communications Smart Metering Network Deployment

    Directory of Open Access Journals (Sweden)

    Alberto Sendin

    2014-04-01

    Full Text Available Smart Grids are becoming a reality all over the world. Nowadays, the research efforts for the introduction and deployment of these grids are mainly focused on the development of the field of Smart Metering. This emerging application requires the use of technologies to access the significant number of points of supply (PoS existing in the grid, covering the Low Voltage (LV segment with the lowest possible costs. Power Line Communications (PLC have been extensively used in electricity grids for a variety of purposes and, of late, have been the focus of renewed interest. PLC are really well suited for quick and inexpensive pervasive deployments. However, no LV grid is the same in any electricity company (utility, and the particularities of each grid evolution, architecture, circumstances and materials, makes it a challenge to deploy Smart Metering networks with PLC technologies, with the Smart Grid as an ultimate goal. This paper covers the evolution of Smart Metering networks, together with the evolution of PLC technologies until both worlds have converged to project PLC-enabled Smart Metering networks towards Smart Grid. This paper develops guidelines over a set of strategic aspects of PLC Smart Metering network deployment based on the knowledge gathered on real field; and introduces the future challenges of these networks in their evolution towards the Smart Grid.

  5. Emulation Platform for Cyber Analysis of Wireless Communication Network Protocols

    Energy Technology Data Exchange (ETDEWEB)

    Van Leeuwen, Brian P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Eldridge, John M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-11-01

    Wireless networking and mobile communications is increasing around the world and in all sectors of our lives. With increasing use, the density and complexity of the systems increase with more base stations and advanced protocols to enable higher data throughputs. The security of data transported over wireless networks must also evolve with the advances in technologies enabling more capable wireless networks. However, means for analysis of the effectiveness of security approaches and implementations used on wireless networks are lacking. More specifically a capability to analyze the lower-layer protocols (i.e., Link and Physical layers) is a major challenge. An analysis approach that incorporates protocol implementations without the need for RF emissions is necessary. In this research paper several emulation tools and custom extensions that enable an analysis platform to perform cyber security analysis of lower layer wireless networks is presented. A use case of a published exploit in the 802.11 (i.e., WiFi) protocol family is provided to demonstrate the effectiveness of the described emulation platform.

  6. Network security with openSSL cryptography for secure communications

    CERN Document Server

    Viega, John; Chandra, Pravir

    2002-01-01

    Most applications these days are at least somewhat network aware, but how do you protect those applications against common network security threats? Many developers are turning to OpenSSL, an open source version of SSL/TLS, which is the most widely used protocol for secure network communications.The OpenSSL library is seeing widespread adoption for web sites that require cryptographic functions to protect a broad range of sensitive information, such as credit card numbers and other financial transactions. The library is the only free, full-featured SSL implementation for C and C++, and it can be used programmatically or from the command line to secure most TCP-based network protocols.Network Security with OpenSSL enables developers to use this protocol much more effectively. Traditionally, getting something simple done in OpenSSL could easily take weeks. This concise book gives you the guidance you need to avoid pitfalls, while allowing you to take advantage of the library?s advanced features. And, inst...

  7. Distributed communications and control network for robotic mining

    Science.gov (United States)

    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.

  8. Near-Field Coupling Communication Technology For Human-Area Networking

    Directory of Open Access Journals (Sweden)

    Ryoji Nagai

    2012-12-01

    Full Text Available We propose a human-area networking technology that uses the surface of the human body as a data transmission path and uses near-field coupling TRXs. This technology aims to achieve a "touch and connect" form of communication and a new concept of "touch the world" by using a quasi-electrostatic field signal that propagates along the surface of the human body. This paper explains the principles underlying near-field coupling communication. Special attention has been paid to common-mode noise since our communication system is strongly susceptible to this. We designed and made a common-mode choke coil and a transformer to act as common-mode noise filters to suppress common-mode noise. Moreover, we describe how we evaluated the quality of communication using a phantom model with the same electrical properties as the human body and present the experimental results for the packet error rate (PER as a function of the signal to noise ratio (SNR both with the common-mode choke coil or the transformer and without them. Finally, we found that our system achieved a PER of less than 10-2 in general office rooms using raised floors, which corresponded to the quality of communication demanded by communication services in ordinary office spaces.

  9. Distributed LMS estimation over networks with quantised communications

    Science.gov (United States)

    Xie, Shoulie; Li, Hongru

    2013-03-01

    This article investigates the problem of distributed least mean-square (D-LMS) estimation over a network with quantised communication. Each node in the network has a quantiser consisting of a first-order dynamical encoder-decoder and can only communicate with its neighbours. Then a new D-LMS estimator is proposed by employing a weighted sum of the internal state differences between each node's quantiser and those of its neighbours. Performance analysis of the proposed quantised D-LMS algorithm is studied in terms of mean-square transient and steady-state measurements. We show that for Gaussian data and sufficiently small step sizes, the proposed cooperative D-LMS with quantisation is mean-square stable in all quantisation levels including the 1-bit case, and its performance approaches the cooperative D-LMS without quantisation when the quantisation step size is fairly small. Furthermore, although in unquantised case (infinite precision), the cooperative D-LMS always outperforms the non-cooperative D-LMS scheme (without communications among the neighbours); however, we show that due to the existence of quantisation error, the cooperative D-LMS with quantisation does not always outperform the non-cooperative D-LMS scheme, especially when the quantisation step size is quite large. Finally, numerical simulations also demonstrate that our theoretical performance matches well with experimental performance.

  10. A Hybrid Networking Model for the Access Layer of the Communication Network for Distribution in Smart Grid

    Directory of Open Access Journals (Sweden)

    Wang Hao

    2016-01-01

    Full Text Available The access layer in the communication network for distribution is an important link in the automation of smart distribution power grid. In current access layer of communication network for distribution in Chinese power grid systems, several communication methods like optical fiber, mediumvoltage carrier communication, 1.8GHz TD-LTE power private wireless network, 230MHz TD-LTE power private wireless network, public wireless network are constructed concurrently and running simultaneously in an identical power supply area. This traditional networking model will cause repeated construction and operation and maintenance difficulties in the communication network of power grid. On the basis of giving a detailed analysis of the radio link budget of TD-LTE power private wireless network in two frequencies, this paper present a multi-communication methods hybrid networking model, which gives a clear boundary for different communication methods based on the isoline with equal signal strength of the TD-LTE power private wireless network and accomplish the optimization of communication resources for distribution.

  11. Wireless Communications and Networking Technologies for Smart Grid: Paradigms and Challenges

    OpenAIRE

    Fang, Xi; Yang, Dejun; Xue, Guoliang

    2011-01-01

    Smart grid, regarded as the next generation power grid, uses two-way flows of electricity and information to create a widely distributed automated energy delivery network. In this work we present our vision on smart grid from the perspective of wireless communications and networking technologies. We present wireless communication and networking paradigms for four typical scenarios in the future smart grid and also point out the research challenges of the wireless communication and networking ...

  12. COMMUNICATION BY MEANS OF THE NEW SOCIAL NETWORKS

    Directory of Open Access Journals (Sweden)

    Purice Suzana

    2012-12-01

    opinion, in this study paper we only partially achieved to highlight the increasingly strong relationship between communication, interactivity and electronic media and, therefore, we hope that this demarche will be continued in other research.

  13. Innovative Networking Concepts Tested on the Advanced Communications Technology Satellite

    Science.gov (United States)

    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.

  14. Networking Alone? Digital Communications and Collective Action in Vietnam

    Directory of Open Access Journals (Sweden)

    Sandra Kurfürst

    2015-01-01

    Full Text Available This article explores the potential for the formation of collective action in Vietnam. Referring to land and labour protests, bauxite mining, anti-China demonstrations, as well as the revision of the 1992 Constitution, the article examines the social movement repertoires diverse groups have adopted to reach their objectives. Drawing on social movement theory and communication power, this contribution shows that apart from access to the technology, citizens’ opportunities to participate in digital networks as well as access to the default communication network of the state are necessary prerequisites in order to attain public attention and possibly to achieve social change. Moreover, this article shows that existing power differentials in Vietnam are reproduced in digital space. It concludes that for different collective behaviours to result in a social movement, it is essential to “switch” and to connect the different networks. For the moment, the call to protect Vietnam’s sovereignty offers common ground for collective action.

  15. Clustering and Beamforming for Efficient Communication in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Francisco Porcel-Rodríguez

    2016-08-01

    Full Text Available 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.

  16. The Engineering Strong Ground Motion Network of the National Autonomous University of Mexico

    Science.gov (United States)

    Velasco Miranda, J. M.; Ramirez-Guzman, L.; Aguilar Calderon, L. A.; Almora Mata, D.; Ayala Hernandez, M.; Castro Parra, G.; Molina Avila, I.; Mora, A.; Torres Noguez, M.; Vazquez Larquet, R.

    2014-12-01

    The coverage, design, operation and monitoring capabilities of the strong ground motion program at the Institute of Engineering (IE) of the National Autonomous University of Mexico (UNAM) is presented. Started in 1952, the seismic instrumentation intended initially to bolster earthquake engineering projects in Mexico City has evolved into the largest strong ground motion monitoring system in the region. Today, it provides information not only to engineering projects, but also to the near real-time risk mitigation systems of the country, and enhances the general understanding of the effects and causes of earthquakes in Mexico. The IE network includes more than 100 free-field stations and several buildings, covering the largest urban centers and zones of significant seismicity in Central Mexico. Of those stations, approximately one-fourth send the observed acceleration to a processing center in Mexico City continuously, and the rest require either periodic visits for the manual recovery of the data or remote interrogation, for later processing and cataloging. In this research, we document the procedures and telecommunications systems used systematically to recover information. Additionally, we analyze the spatial distribution of the free-field accelerographs, the quality of the instrumentation, and the recorded ground motions. The evaluation criteria are based on the: 1) uncertainty in the generation of ground motion parameter maps due to the spatial distribution of the stations, 2) potential of the array to provide localization and magnitude estimates for earthquakes with magnitudes greater than Mw 5, and 3) adequacy of the network for the development of Ground Motion Prediction Equations due to intra-plate and intra-slab earthquakes. We conclude that the monitoring system requires a new redistribution, additional stations, and a substantial improvement in the instrumentation and telecommunications. Finally, we present an integral plan to improve the current network

  17. Propagation, cascades, and agreement dynamics in complex communication and social networks

    Science.gov (United States)

    Lu, Qiming

    -range communication links are added on top of the random geometric graph, resulting in a "small-world"-like network and yielding a significantly reduced time to reach global agreement. We construct a finite-size scaling analysis for the agreement times in this case. When applying the model of Naming Game on empirical social networks, this stylized agent-based model captures essential features of agreement dynamics in a network of autonomous agents, corresponding to the development of shared classification schemes in a network of artificial agents or opinion spreading and social dynamics in social networks. Our study focuses on the impact that communities in the underlying social graphs have on the outcome of the agreement process. We find that networks with strong community structure hinder the system from reaching global agreement; the evolution of the Naming Game in these networks maintains clusters of coexisting opinions indefinitely. Further, we investigate agent-based network strategies to facilitate convergence to global consensus.

  18. Inter–Vehicular Communications Using Wireless Ad–Hoc Networks

    Directory of Open Access Journals (Sweden)

    R. Aquino–Santos

    2008-10-01

    Full Text Available This paper proposes a new routing algorithm to facilitate communication in highly mobile wireless ad–hoc networks for motorway environments with no physical infrastructure which undergo frequent topological changes. This new reactive routing algorithm for inter–vehicular communication is based on location information in which the source node ascertains the position of its communication partner before it initiates communication. The advantage of this algorithm is that it does not require global knowledge to send information between transmitter–receiver pairs. Instead, this algorithm requires knowledge of the relative positions of its neighbor nodes and the position of the destination. This paper discusses simulations of 250 vehicles driving on a six–lane circular highway using Location Routing Algorithm with Cluster–Based Flooding (LORA–CBF. Highway vehicular mobility is simulated by a microscopic traffic model, developed in OPNET, to evaluate the performance of the LORA–CBF and Greedy Perimeter Stateless Routing (GPSR algorithms in terms of Route Discovery Time (RDT, End–to–End Delay (EED, Routing Overhead (RO, Routing Load (RL and Delivery Ratio (DR.

  19. Analysis, Synthesis and Experiments of Networked Platoons with Communication Constraints

    Directory of Open Access Journals (Sweden)

    Ligang Wu

    2017-02-01

    Full Text Available This paper investigates the analysis and synthesis of networked vehicle platoons with communication delays, packet dropouts and disorders. In order to deal with the effects of the communication constraints, we introduce a novel Smart Data Processor (SDP for each vehicle, by which the latest data packets from logic Data Packet Processor and the matched data packet from its Buffer can be obtained. Based on this mechanism, a leader-predecessor-follower control strategy is proposed. In order to guarantee the asymptotic and string stability, the platoon control problem is transformed into a multi-objective H∞-type synthesis problem with the multiple time-varying delays. A sufficient condition for designing the controller gain is derived by solving a set of linear matrix inequalities. Numerous simulations and experiments with laboratory scale Arduino cars show the efficiency of the proposed methods.

  20. Basic limits on protocol information in data communications networks

    Science.gov (United States)

    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.

  1. Secure and Authenticated Data Communication in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Omar Alfandi

    2015-08-01

    Full Text Available 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.

  2. Ultra-Reliable Communications in Failure-Prone Realistic Networks

    DEFF Research Database (Denmark)

    Gerardino, Guillermo Andrés Pocovi; Lauridsen, Mads; Alvarez, Beatriz Soret

    2016-01-01

    We investigate the potential of different diversity and interference management techniques to achieve the required downlink SINR outage probability for ultra-reliable communications. The evaluation is performed in a realistic network deployment based on site-specific data from a European capital....... Micro and macroscopic diversity techniques are proved to be important enablers of ultra-reliable communications. Particularly, it is shown how a 4x4 MIMO scheme with three orders of macroscopic diversity can achieve the required SINR outage performance. Smaller gains are obtained from interference...... cancellation, since this technique does not increase the diversity order of the desired signal. In addition, failures or malfunction of the cellular infrastructure are analysed. Among different types of failures evaluated, results show that failures spanning over large geographical areas can have a significant...

  3. The Complexity of Patients' Health Communication Social Networks: A Broadening of Physician Communication.

    Science.gov (United States)

    Nimmon, Laura; Regehr, Glenn

    2017-12-22

    Phenomenon: Patients have access to a wide variety of sources of information about their health in their day-to-day contexts. This can sometimes result in discordance between a physician's perception of a patient's health issue and a patient's perception of their health issue. Even after the physician has negotiated an understanding and treatment plan with a patient, subsequent interactions outside the physician-patient encounter may modify the patient's understanding of their health issue. A patient's reinterpretation of his or her health issue can then result in nonadherence of the treatment plan or even alternative treatment plans that the physician perceives as being unsatisfactory. Current models of physician-patient communication do not prepare physicians to manage this phenomenon. Using an ethnographic and a social network analysis research design, participants' patterns of social interaction around health information were investigated over a yearlong period (2012-2013) in a small rural community in Western Canada. Data included (a) individual interviews, (b) focus group interviews, and (c) field notes. Data were analyzed in a three-stage process: (a) item analysis, (b) pattern analysis, and (c) structural analysis. The findings highlight how physicians are only one nodal point in patients' broad, multilayered networks of communication. Interactions around health topics were not isolated events but rather occurred in various patterns of social interactions that were longitudinal and iterative. Meaning making around health topics was constructed, shared, elaborated, reconstructed, and interpreted in participants' social networks, as information was distributed through a complex temporal system of interpersonal ties. Insights: Issues concerning physician communication have been a long-standing conversation in the field of medical education. Many competency frameworks have attempted to encompass this core competency in their elaboration of the physician

  4. Site classification of Indian strong motion network using response spectra ratios

    Science.gov (United States)

    Chopra, Sumer; Kumar, Vikas; Choudhury, Pallabee; Yadav, R. B. S.

    2018-03-01

    In the present study, we tried to classify the Indian strong motion sites spread all over Himalaya and adjoining region, located on varied geological formations, based on response spectral ratio. A total of 90 sites were classified based on 395 strong motion records from 94 earthquakes recorded at these sites. The magnitude of these earthquakes are between 2.3 and 7.7 and the hypocentral distance for most of the cases is less than 50 km. The predominant period obtained from response spectral ratios is used to classify these sites. It was found that the shape and predominant peaks of the spectra at these sites match with those in Japan, Italy, Iran, and at some of the sites in Europe and the same classification scheme can be applied to Indian strong motion network. We found that the earlier schemes based on description of near-surface geology, geomorphology, and topography were not able to capture the effect of sediment thickness. The sites are classified into seven classes (CL-I to CL-VII) with varying predominant periods and ranges as proposed by Alessandro et al. (Bull Seismol Soc Am 102:680-695 2012). The effect of magnitudes and hypocentral distances on the shape and predominant peaks were also studied and found to be very small. The classification scheme is robust and cost-effective and can be used in region-specific attenuation relationships for accounting local site effect.

  5. Mechanically strong dual responsive nanocomposite double network hydrogel for controlled drug release of asprin.

    Science.gov (United States)

    Chen, Yang; Song, Guocheng; Yu, Junrong; Wang, Yan; Zhu, Jing; Hu, Zuming

    2018-03-08

    Mechanically strong dual/multi-stimuli-responsive smart hydrogels have attracted extensive attention in recent years. A novel tough, mechanical strong and biocompatible dual pH- and temperature- responsive poly (N-isopropylacrylamide) /clay (laponite XLG)/carboxymethyl chitosan (CMCTs) /genipin nanocomposite double network hydrogel was synthesized through a facile, one-pot free radical polymerization initiated by the ultraviolet light, using clay and the natural molecular-genipin as the cross-linkers instead of toxic organic molecules. Crucial factors, the content of CMCTs, clay and genipin, for synthesizing the mechanical strong hydrogels were investigated. When the content of CMCTs, clay and genipin were 5 wt%, 33.3 wt% and 0.175 wt%, respectively (to the weight of N-isopropylacrylamide), these prepared hydrogels exhibited a high tensile strength of 137.9 kPa at the failure strain of 446.1%. Furthermore, the relationship between swelling and deswelling rate of the synthesized hydrogels and the above crucial factors were also studied. Besides, the synthesized hydrogels displayed a considerable controlled release property of asprin by tuning their inner crosslink density. Owing to this property, they may have great potential in the drug delivery systems. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Role of Strong versus Weak Networks in Small Business Growth in an Emerging Economy

    Directory of Open Access Journals (Sweden)

    M. Kamil Kozan

    2014-02-01

    Full Text Available The study tests whether strong rather than weak ties account for small business growth in Turkey. Data were collected by means of a questionnaire filled out by the owners of small firms operating in four cities. Growth is comprised of two main areas, production expansion and knowledge acquisition. Results show that strong ties are positively related to both types of growth. In contrast, loose ties have no effect on small business growth in either area. This finding is attributed to the influence of the collectivistic nature of the mainstream Turkish culture, where owners of small businesses are likely to rely on in-groups rather than out-groups for advice and for financial support. Implications of relative absence of weak ties for small business growth and innovation in emerging economies are discussed. The findings suggest that culture should be included as a contingency variable in future studies of network strength and growth relationship. The paper also discusses the possible moderating role of affective and cognition-based trust in the relation of strong and weak ties to small business growth.

  7. Integrating Space Communication Network Capabilities via Web Portal Technologies

    Science.gov (United States)

    Johnston, Mark D.; Lee, Carlyn-Ann; Lau, Chi-Wung; Cheung, Kar-Ming; Levesque, Michael; Carruth, Butch; Coffman, Adam; Wallace, Mike

    2014-01-01

    We have developed a service portal prototype as part of an investigation into the feasibility of using Java portlet technology as a means of providing integrated access to NASA communications network services. Portal servers provide an attractive platform for this role due to the various built-in collaboration applications they can provide, combined with the possibility to develop custom inter-operating portlets to extent their functionality while preserving common presentation and behavior. This paper describes various options for integration of network services related to planning and scheduling, and results based on use of a popular open-source portal framework. Plans are underway to develop an operational SCaN Service Portal, building on the experiences reported here.

  8. Artificial Neural Network for Location Estimation in Wireless Communication Systems

    Directory of Open Access Journals (Sweden)

    Chien-Sheng Chen

    2012-03-01

    Full Text Available 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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  11. ACTS TDMA network control. [Advanced Communication Technology Satellite

    Science.gov (United States)

    Inukai, T.; Campanella, S. J.

    1984-01-01

    This paper presents basic network control concepts for the Advanced Communications Technology Satellite (ACTS) System. Two experimental systems, called the low-burst-rate and high-burst-rate systems, along with ACTS ground system features, are described. The network control issues addressed include frame structures, acquisition and synchronization procedures, coordinated station burst-time plan and satellite-time plan changes, on-board clock control based on ground drift measurements, rain fade control by means of adaptive forward-error-correction (FEC) coding and transmit power augmentation, and reassignment of channel capacities on demand. The NASA ground system, which includes a primary station, diversity station, and master control station, is also described.

  12. Network coding multiuser scheme for indoor visible light communications

    Science.gov (United States)

    Zhang, Jiankun; Dang, Anhong

    2017-12-01

    Visible light communication (VLC) is a unique alternative for indoor data transfer and developing beyond point-to-point. However, for realizing high-capacity networks, VLC is facing challenges including the constrained bandwidth of the optical access point and random occlusion. A network coding scheme for VLC (NC-VLC) is proposed, with increased throughput and system robustness. Based on the Lambertian illumination model, theoretical decoding failure probability of the multiuser NC-VLC system is derived, and the impact of the system parameters on the performance is analyzed. Experiments demonstrate the proposed scheme successfully in the indoor multiuser scenario. These results indicate that the NC-VLC system shows a good performance under the link loss and random occlusion.

  13. SPECIFICITY OF COMMUNICATION DOCTOR – PATIENT, ONLINE, THROUGH SOCIAL NETWORKS

    Directory of Open Access Journals (Sweden)

    Florin-Alexandru LUCA

    2014-12-01

    Full Text Available A survey in 2013 of Division Market Research Group Rentrop Straton Romanian-German - "state services and private clinics. Comparative Analysis ", highlights the fact that into urban population in Romania, the internet is the most popular source of information on health services. According to the survey, 81.9% of respondents use the Internet to find out about the best doctors available to them. Preferences of respondents to the online environment as the main source of information translates into ease of access and the possibility of interaction, but also trust recommendations based on personal experiences, recommendations can be found through discussion forums, mostly or comments left on pages on social networking sites. In the present study we try to emphasize the specificity of communication physician - patient online through social networks.

  14. INTEGRITY ASSESSMENT OF INFORMATION EXCHANGE IN COMMUNICATION NETWORKS OF THE TYPICAL AIRPORTS

    Directory of Open Access Journals (Sweden)

    2016-01-01

    Full Text Available The article considers the evaluation method of information accuracy in communication networks such as radial and ring structure with a single center. The possibility of the assessment probability of communication networks no-failure operation among airport structural divisions with a parallel accounting network fragment resistance to destructive impacts with a probabilistic metrics is given.For probabilities qualimetry of communication network failures use of operative availability function along with recommendations to use theoretical distributions for physically various communication networks is suggested. For a logical chain of the analysis of survival capabilities a range of problems to be stated while making prior and posteriori estimatesis specified.

  15. Research of the self-healing technologies in the optical communication network of distribution automation

    Science.gov (United States)

    Wang, Hao; Zhong, Guoxin

    2018-03-01

    Optical communication network is the mainstream technique of the communication networks for distribution automation, and self-healing technologies can improve the in reliability of the optical communication networks significantly. This paper discussed the technical characteristics and application scenarios of several network self-healing technologies in the access layer, the backbone layer and the core layer of the optical communication networks for distribution automation. On the base of the contrastive analysis, this paper gives an application suggestion of these self-healing technologies.

  16. 10 CFR 73.54 - Protection of digital computer and communication systems and networks.

    Science.gov (United States)

    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 adequately...

  17. Communication: Strong laser alignment of solvent-solute aggregates in the gas-phase

    Science.gov (United States)

    Trippel, Sebastian; Wiese, Joss; Mullins, Terry; Küpper, Jochen

    2018-03-01

    Strong quasi-adiabatic laser alignment of the indole-water-dimer clusters, an amino-acid chromophore bound to a single water molecule through a hydrogen bond, was experimentally realized. The alignment was visualized through ion and electron imaging following strong-field ionization. Molecular-frame photoelectron angular distributions showed a clear suppression of the electron yield in the plane of the ionizing laser's polarization, which was analyzed as strong alignment of the molecular cluster with ⟨cos2 θ2D⟩ ≥ 0.9.

  18. A Novel Multi-network Convergence Communication Mechanism for Electricity Information Acquisition System Test Platform

    Directory of Open Access Journals (Sweden)

    Min XIANG

    2014-03-01

    Full Text Available Electricity Information Acquisition System (EIAS test platform is used to evaluate the communication performance of the different communication methods. For realizing the reliable and quick information interaction in the test terminal, a hierarchical structure multi-network convergence communication mechanism is designed. The convergence communication mechanism is divided into the communication interface convergence layer, the core convergence layer and the business convergence layer to realize the information interaction among the Ethernet communication, power line carrier communication, RS-485 communication and wireless communication. Combined with the tunnel transmission mechanism, the buffer pool mechanism, the communication check mechanism and the timeout control mechanism, the multi-network convergence communication mechanism can effectively improve the communication performance of the test terminal. The test results show that the mechanism can satisfy the real-time and reliability requirements for the electricity information acquisition system test platform.

  19. Communication Network Architectures for Smart-Wind Power Farms

    Directory of Open Access Journals (Sweden)

    Mohamed A. Ahmed

    2014-06-01

    Full Text Available Developments in the wind power industry have enabled a new generation of wind turbines with longer blades, taller towers, higher efficiency, and lower maintenance costs due to the maturity of related technologies. Nevertheless, wind turbines are still blind machines because the control center is responsible for managing and controlling individual wind turbines that are turned on or off according to demand for electricity. In this paper, we propose a communication network architecture for smart-wind power farms (Smart-WPFs. The proposed architecture is designed for wind turbines to communicate directly and share sensing data in order to maximize power generation, WPF availability, and turbine efficiency. We also designed a sensor data frame structure to carry sensing data from different wind turbine parts such as the rotor, transformer, nacelle, etc. The data frame includes a logical node ID (LNID, sensor node ID (SNID, sensor type (ST, and sensor data based on the International Electrotechnical Commission (IEC 61400-25 standard. We present an analytical model that describes upstream traffic between the wind turbines and the control center. Using a queueing theory approach, the upstream traffic is evaluated in view of bandwidth utilization and average queuing delay. The performance of the proposed network architectures are evaluated by using analytical and simulation models.

  20. Alternative Path Communication in Wide-Scale Cluster-Tree Wireless Sensor Networks Using Inactive Periods.

    Science.gov (United States)

    Leão, Erico; Montez, Carlos; Moraes, Ricardo; Portugal, Paulo; Vasques, Francisco

    2017-05-06

    The IEEE 802.15.4/ZigBee cluster-tree topology is a suitable technology to deploy wide-scale Wireless Sensor Networks (WSNs). These networks are usually designed to support convergecast traffic, where all communication paths go through the PAN (Personal Area Network) coordinator. Nevertheless, peer-to-peer communication relationships may be also required for different types of WSN applications. That is the typical case of sensor and actuator networks, where local control loops must be closed using a reduced number of communication hops. The use of communication schemes optimised just for the support of convergecast traffic may result in higher network congestion and in a potentially higher number of communication hops. Within this context, this paper proposes an Alternative-Route Definition (ARounD) communication scheme for WSNs. The underlying idea of ARounD is to setup alternative communication paths between specific source and destination nodes, avoiding congested cluster-tree paths. These alternative paths consider shorter inter-cluster paths, using a set of intermediate nodes to relay messages during their inactive periods in the cluster-tree network. Simulation results show that the ARounD communication scheme can significantly decrease the end-to-end communication delay, when compared to the use of standard cluster-tree communication schemes. Moreover, the ARounD communication scheme is able to reduce the network congestion around the PAN coordinator, enabling the reduction of the number of message drops due to queue overflows in the cluster-tree network.

  1. An Interdisciplinary Network Making Progress on Climate Change Communication

    Science.gov (United States)

    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.

  2. Near Earth Network (NEN) CubeSat Communications

    Science.gov (United States)

    Schaire, Scott

    2017-01-01

    The NASA Near Earth Network (NEN) consists of globally distributed tracking stations, including NASA, commercial, and partner ground stations, that are strategically located to maximize the coverage provided to a variety of orbital and suborbital missions, including those in LEO (Low Earth Orbit), GEO (Geosynchronous Earth Orbit), HEO (Highly Elliptical Orbit), lunar and L1-L2 orbits. The NEN's future mission set includes and will continue to include CubeSat missions. The first NEN-supported CubeSat mission will be the Cubesat Proximity Operations Demonstration (CPOD) launching into LEO in 2017. The majority of the CubeSat missions destined to fly on EM-1, launching in late 2018, many in a lunar orbit, will communicate with ground-based stations via X-band and will utilize the NASA Jet Propulsion Laboratory (JPL)-developed IRIS (Satellite Communication for Air Traffic Management) radio. The NEN recognizes the important role CubeSats are beginning to play in carrying out NASAs mission and is therefore investigating the modifications needed to provide IRIS radio compatibility. With modification, the NEN could potentially expand support to the EM-1 (Exploration Mission-1) lunar CubeSats. The NEN could begin providing significant coverage to lunar CubeSat missions utilizing three to four of the NEN's mid-latitude sites. This coverage would supplement coverage provided by the JPL Deep Space Network (DSN). The NEN, with smaller apertures than DSN, provides the benefit of a larger beamwidth that could be beneficial in the event of uncertain ephemeris data. In order to realize these benefits the NEN would need to upgrade stations targeted based on coverage ability and current configuration ease of upgrade, to ensure compatibility with the IRIS radio. In addition, the NEN is working with CubeSat radio developers to ensure NEN compatibility with alternative CubeSat radios for Lunar and L1-L2 CubeSats. The NEN has provided NEN compatibility requirements to several radio

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

    Science.gov (United States)

    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.

  4. The Quake-Catcher Network: A Community-Led, Strong-Motion Network with Implications for Earthquake Advanced Alert

    Science.gov (United States)

    Cochran, E. S.; Lawrence, J. F.; Christensen, C. M.; Jakka, R. S.; Chung, A. I.

    2009-12-01

    The goal of the Quake-Catcher Network (QCN) is to dramatically increase the number of strong-motion observations by exploiting recent advances in sensing technologies and cyberinfrastructure. Micro-Electro-Mechanical Systems (MEMS) triaxial accelerometers are very low cost (50-100), interface to any desktop computer via USB cable, and provide high-quality acceleration data. Preliminary shake table tests show the MEMS accelerometers can record high-fidelity seismic data and provide linear phase and amplitude response over a wide frequency range. Volunteer computing provides a mechanism to expand strong-motion seismology with minimal infrastructure costs, while promoting community participation in science. Volunteer computing also allows for rapid transfer of metadata, such as that used to rapidly determine the magnitude and location of an earthquake, from participating stations. QCN began distributing sensors and software to K-12 schools and the general public in April 2008 and has grown to roughly 1000 stations. Initial analysis shows metadata are received within 1-14 seconds from the observation of a trigger; the larger data latencies are correlated with greater server-station distances. Currently, we are testing a series of triggering algorithms to maximize the number of earthquakes captured while minimizing false triggers. We are also testing algorithms to automatically detect P- and S-wave arrivals in real time. Trigger times, wave amplitude, and station information are currently uploaded to the server for each trigger. Future work will identify additional metadata useful for quickly determining earthquake location and magnitude. The increased strong-motion observations made possible by QCN will greatly augment the capability of seismic networks to quickly estimate the location and magnitude of an earthquake for advanced alert to the public. In addition, the dense waveform observations will provide improved source imaging of a rupture in near-real-time. These

  5. A Mars Communication Constellation For Human Exploration and Network Science

    Science.gov (United States)

    Castellini, Francesco; Lavagna, Michèle; Simonetto, Andrea

    Mars is perhaps the primary target of all space exploration programs, and a massive robotic and human exploration will ask for a suitable communication link between Earth and the Red planet. The paper analyses the possibility of exploiting a small spacecrafts constellation around Mars to offer a complete and continuous coverage of possible elements on the planet, taking advantage of optical transmission techniques. Since the first human expedition will most likely not be launched in the next 15-20 years, the study foresees such a communications mission to be implemented after 2020, and in light of the future presence of explorers on the surface a high data rate requirement is imposed, in order to allow video transmissions. In addition, the set-up of a communication constellation around Mars would give the opportunity of exploiting this multi-platform infrastructure to perform network science, that would largely increase our knowledge of the planet. The paper covers all technical aspects of the feasibility study for the primary communications mission, and secondary scientific opportunities are suggested. The proposed communication architecture is quite complex and includes six 530kg spacecrafts on two different orbital planes, plus one redundant unit per plane, that ensure complete coverage of the planet's surface; communications between the satellites and Earth are achieved through optical links, that allow high data rates with lower mass and power consumption with respect to traditional radio-frequency technology (1) (2), while inter-satellite links and spacecrafts-to- Mars connections are ensured by radio transmissions. The worst-case optical link data rate varies from 10.2 Mbps in downlink to 13.7 Mbps in uplink. Inter-satellites data rate stays the 4.3-7.8 Mbps range on Ka-band, while spacecraft-Mars surface communications occur on the X band offering a 4.3 Mbps data rate. A complete trade-off analysis has been performed in terms of on board subsystems design

  6. Finding strong gravitational lenses in the Kilo Degree Survey with Convolutional Neural Networks

    Science.gov (United States)

    Petrillo, C. E.; Tortora, C.; Chatterjee, S.; Vernardos, G.; Koopmans, L. V. E.; Verdoes Kleijn, G.; Napolitano, N. R.; Covone, G.; Schneider, P.; Grado, A.; McFarland, J.

    2017-11-01

    The volume of data that will be produced by new-generation surveys requires automatic classification methods to select and analyse sources. Indeed, this is the case for the search for strong gravitational lenses, where the population of the detectable lensed sources is only a very small fraction of the full source population. We apply for the first time a morphological classification method based on a Convolutional Neural Network (CNN) for recognizing strong gravitational lenses in 255 deg2 of the Kilo Degree Survey (KiDS), one of the current-generation optical wide surveys. The CNN is currently optimized to recognize lenses with Einstein radii ≳1.4 arcsec, about twice the r-band seeing in KiDS. In a sample of 21 789 colour-magnitude selected luminous red galaxies (LRGs), of which three are known lenses, the CNN retrieves 761 strong-lens candidates and correctly classifies two out of three of the known lenses. The misclassified lens has an Einstein radius below the range on which the algorithm is trained. We down-select the most reliable 56 candidates by a joint visual inspection. This final sample is presented and discussed. A conservative estimate based on our results shows that with our proposed method it should be possible to find ∼100 massive LRG-galaxy lenses at z ≲ 0.4 in KiDS when completed. In the most optimistic scenario, this number can grow considerably (to maximally ∼2400 lenses), when widening the colour-magnitude selection and training the CNN to recognize smaller image-separation lens systems.

  7. Special Issue on 5G Communications and Experimental Trials with Heterogeneous and Agile Mobile networks

    OpenAIRE

    Sejun Song; KyungHi Chang; Chanho Yoon; Jong‐Moon Chung

    2018-01-01

    5th generation mobile networks, 5G, are the proposed next‐generation communication network standards. In addition to providing more than 1 Gb per second faster speeds, 5G will be a global game changer from technological, economic, societal, and environmental perspectives by integrating multiple networks in diverse sectors for various up to date applications such as the Internet of Things (IoT), device‐to‐device direct communication (D2D), vehicular communications (V2X), and disaster resilient...

  8. Directedness of information flow in mobile phone communication networks.

    Directory of Open Access Journals (Sweden)

    Fernando Peruani

    Full Text Available 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.

  9. Wireless Network Cocast: Cooperative Communications with Space-Time Network Coding

    Science.gov (United States)

    2011-04-21

    Multiple-Output ML Maximum Likelihood MMSE Minimum Mean Square Error OFDM Orthogonal Frequency-Division Multiplexing OFDMA Orthogonal Frequency-Division...contrast, is intended to improve the communication reliability. Lastly, while the traditional network coding is invariant in terms of node locations, the... MMSE ) detector, which is optimal among linear detectors. At high SNR, however, we expect that MMSE detector and our multiuser detector have comparable

  10. Communication: Thermodynamics of condensed matter with strong pressure-energy correlations

    DEFF Research Database (Denmark)

    Ingebrigtsen, Trond; Bøhling, Lasse; Schrøder, Thomas

    2012-01-01

    in the phase diagram of invariant structure and dynamics) are described by h(ρ)/T = Const., (2) the density-scaling exponent is a function of density only, and (3) a Grüneisen-type equation of state applies for the configurational degrees of freedom. For strongly correlating atomic systems one has h(ρ) = ∑n...

  11. The usage of Internet social networking as a tool of linguist students' intercultural communication competence growth

    Directory of Open Access Journals (Sweden)

    Сергей Владимирович Сороколетов

    2009-06-01

    Full Text Available In work concepts «the intercultural communicative competence», «a social network», possibilities of use social the Internet of network FaceBook in training of students-linguists are described.

  12. MmWave Vehicle-to-Infrastructure Communication :Analysis of Urban Microcellular Networks

    Science.gov (United States)

    2017-05-01

    Vehicle-to-infrastructure (V2I) communication may provide high data rates to vehicles via millimeterwave (mmWave) microcellular networks. This report uses stochastic geometry to analyze the coverage of urban mmWave microcellular networks. Prior work ...

  13. On Study of Construction of New Generation Intelligent Communication Network for Distribution System

    Science.gov (United States)

    Wu, Dan; Zhang, Xueyan

    2017-09-01

    many new technological means are integrated in the new network of smart electricity distribution including electric power technology, control technology and information technology, and in this area, people carry out profound research to the construction of communication network and power distribution network. This paper analyzes specific structures of the communication network for distribution system, discusses the development trend of it, explores its technical system in depth, and finally proposes some concrete constructive strategies, hoping to be a valuable reference for related research persons.

  14. High-throughput and low-latency network communication with NetIO

    OpenAIRE

    Schumacher, Jorn; Plessl, Christian; Vandelli, Wainer

    2017-01-01

    HPC network technologies like Infiniband, TrueScale or OmniPath provide low-latency and high-throughput communication between hosts, which makes them attractive options for data-acquisition systems in large-scale high-energy physics experiments. Like HPC networks, DAQ networks are local and include a well specified number of systems. Unfortunately traditional network communication APIs for HPC clusters like MPI or PGAS target exclusively the HPC community and are not suited well for DAQ appli...

  15. Signaling and Reciprocity: Robust Decentralized Information Flows in Social, Communication, and Computer Networks

    OpenAIRE

    Galuba, Wojciech

    2011-01-01

    Complex networks exist for a number of purposes. The neural, metabolic and food networks ensure our survival, while the social, economic, transportation and communication networks allow us to prosper. Independently of the purposes and particularities of the physical embodiment of the networks, one of their fundamental functions is the delivery of information from one part of the network to another. Gossip and diseases diffuse in the social networks, ...

  16. Network Coded Cooperative Communication in a Real-Time Wireless Hospital Sensor Network.

    Science.gov (United States)

    Prakash, R; Balaji Ganesh, A; Sivabalan, Somu

    2017-05-01

    The paper presents a network coded cooperative communication (NC-CC) enabled wireless hospital sensor network architecture for monitoring health as well as postural activities of a patient. A wearable device, referred as a smartband is interfaced with pulse rate, body temperature sensors and an accelerometer along with wireless protocol services, such as Bluetooth and Radio-Frequency transceiver and Wi-Fi. The energy efficiency of wearable device is improved by embedding a linear acceleration based transmission duty cycling algorithm (NC-DRDC). The real-time demonstration is carried-out in a hospital environment to evaluate the performance characteristics, such as power spectral density, energy consumption, signal to noise ratio, packet delivery ratio and transmission offset. The resource sharing and energy efficiency features of network coding technique are improved by proposing an algorithm referred as network coding based dynamic retransmit/rebroadcast decision control (LA-TDC). From the experimental results, it is observed that the proposed LA-TDC algorithm reduces network traffic and end-to-end delay by an average of 27.8% and 21.6%, respectively than traditional network coded wireless transmission. The wireless architecture is deployed in a hospital environment and results are then successfully validated.

  17. Blocking probabilities in mobile communications networks with time-varying rates ad redialing subscribers

    NARCIS (Netherlands)

    Abdalla, Nadra; Boucherie, Richardus J.

    Call-blocking probabilities are among the key performance measures in mobile communications networks. For their analysis, mobile networks can be modelled as networks of Erlang loss queues with common capacity restrictions dictated by the allocation of frequencies to the cells of the network.

  18. Innovation and communicative action: health management networks and technologies.

    Science.gov (United States)

    Rivera, Francisco Javier Uribe; Artmann, Elizabeth

    2016-11-03

    This article discusses elements of a theory of innovation from the perspective of innovation networks and social construction of technology, based on Habermas' Theory of Communicative Action and authors from the Sociology of Innovation. Based on the theoretical framework of the communicative production of scientific facts, we focus on innovation management as a basic dimension that must meet some organizational and methodological requirements in order to power its results. We present and discuss instruments such as Situational Planning, Prospective Analysis, Strategic Portfolio Management, and Networks Management that can help deal with the challenge of innovation and exploration of the future. We conclude that network organizational formats centered on reflexivity of interdisciplinary groups and planning approaches that encourage innovation criteria in assessing the attractiveness of activities and that help anticipate forms of innovation through systematic prospective analysis can potentiate the process of generating innovation as a product of networks. Resumo: No artigo são discutidos elementos de uma teoria da inovação numa perspectiva de redes de inovação e de construção social da tecnologia, a partir da Teoria do Agir Comunicativo de Habermas e de autores da Sociologia da Inovação. Com base no marco teórico da produção comunicativa de fatos científicos, focamos a gestão da inovação como uma dimensão fundamental que deve contemplar alguns requisitos, tanto de natureza organizacional quanto metodológica, para potencializar seus resultados. Apresentamos e discutimos instrumentos como o Planejamento Situacional, a Análise Prospectiva, a Gestão Estratégica de Portfólios e a Gestão de Redes que podem contribuir para o desafio da inovação e exploração do futuro. Conclui-se que formas organizativas em rede, centradas na reflexividade de grupos interdisciplinares, e enfoques de planejamento que estimulem o uso de critérios de inovação na

  19. Dramatic reduction of dimensionality in large biochemical networks owing to strong pair correlations

    Science.gov (United States)

    Dworkin, Michael; Mukherjee, Sayak; Jayaprakash, Ciriyam; Das, Jayajit

    2012-01-01

    Large multi-dimensionality of high-throughput datasets pertaining to cell signalling and gene regulation renders it difficult to extract mechanisms underlying the complex kinetics involving various biochemical compounds (e.g. proteins and lipids). Data-driven models often circumvent this difficulty by using pair correlations of the protein expression levels to produce a small number (fewer than 10) of principal components, each a linear combination of the concentrations, to successfully model how cells respond to different stimuli. However, it is not understood if this reduction is specific to a particular biological system or to nature of the stimuli used in these experiments. We study temporal changes in pair correlations, described by the covariance matrix, between concentrations of different molecular species that evolve following deterministic mass-action kinetics in large biologically relevant reaction networks and show that this dramatic reduction of dimensions (from hundreds to less than five) arises from the strong correlations between different species at any time and is insensitive to the form of the nonlinear interactions, network architecture, and to a wide range of values of rate constants and concentrations. We relate temporal changes in the eigenvalue spectrum of the covariance matrix to low-dimensional, local changes in directions of the system trajectory embedded in much larger dimensions using elementary differential geometry. We illustrate how to extract biologically relevant insights such as identifying significant timescales and groups of correlated chemical species from our analysis. Our work provides for the first time, to our knowledge, a theoretical underpinning for the successful experimental analysis and points to a way to extract mechanisms from large-scale high-throughput datasets. PMID:22378749

  20. Dramatic reduction of dimensionality in large biochemical networks owing to strong pair correlations.

    Science.gov (United States)

    Dworkin, Michael; Mukherjee, Sayak; Jayaprakash, Ciriyam; Das, Jayajit

    2012-08-07

    Large multi-dimensionality of high-throughput datasets pertaining to cell signalling and gene regulation renders it difficult to extract mechanisms underlying the complex kinetics involving various biochemical compounds (e.g. proteins and lipids). Data-driven models often circumvent this difficulty by using pair correlations of the protein expression levels to produce a small number (fewer than 10) of principal components, each a linear combination of the concentrations, to successfully model how cells respond to different stimuli. However, it is not understood if this reduction is specific to a particular biological system or to nature of the stimuli used in these experiments. We study temporal changes in pair correlations, described by the covariance matrix, between concentrations of different molecular species that evolve following deterministic mass-action kinetics in large biologically relevant reaction networks and show that this dramatic reduction of dimensions (from hundreds to less than five) arises from the strong correlations between different species at any time and is insensitive to the form of the nonlinear interactions, network architecture, and to a wide range of values of rate constants and concentrations. We relate temporal changes in the eigenvalue spectrum of the covariance matrix to low-dimensional, local changes in directions of the system trajectory embedded in much larger dimensions using elementary differential geometry. We illustrate how to extract biologically relevant insights such as identifying significant timescales and groups of correlated chemical species from our analysis. Our work provides for the first time, to our knowledge, a theoretical underpinning for the successful experimental analysis and points to a way to extract mechanisms from large-scale high-throughput datasets.

  1. Increasing capacity of baseband digital data communication networks

    Energy Technology Data Exchange (ETDEWEB)

    Frankel, R.S.; Herman, A.

    This invention provides broadbank network capabilities for baseband digital collision detection transceiver equipment for communication between a plurality of data stations by affording simultaneous transmission of multiple channels over a broadband pass transmission link such as a coaxial cable. Thus, a fundamental carrier wave is transmitted on said link, received at local data stations and used to detect signals on different baseband channels for reception. For transmission the carrier wave typically is used for segregating a plurality of at least two transmission channels into typically single sideband upper and lower pass bands of baseband bandwidth capability adequately separated with guard bands to permit simple separation for receiving by means of pass band filters, etc.

  2. Increasing capacity of baseband digital data communication networks

    Energy Technology Data Exchange (ETDEWEB)

    Frankel, Robert S. (Centereach, NY); Herman, Alexander (Hertzelia, IL)

    1985-01-01

    This invention provides broadband network capabilities for baseband digital collision detection transceiver equipment for communication between a plurality of data stations by affording simultaneous transmission of multiple channels over a broadband pass transmission link such as a coaxial cable. Thus, a fundamental carrier wave is transmitted on said link, received at local data stations and used to detect signals on different baseband channels for reception. For transmission the carrier wave typically is used for segregating a plurality of at least two transmission channels into typically single sideband upper and lower pass bands of baseband bandwidth capability adequately separated with guard bands to permit simple separation for receiving by means of pass band filters, etc.

  3. Increasing capacity of baseband digital data communication networks

    Energy Technology Data Exchange (ETDEWEB)

    Frankel, R. S.; Herman, A.

    1985-04-16

    This invention provides broadband network capabilities for baseband digital collision detection transceiver equipment for communication between a plurality of data stations by affording simultaneous transmission of multiple channels over a broadband pass transmission link such as a coaxial cable. Thus, a fundamental carrier wave is transmitted on said link, received at local data stations and used to detect signals on different baseband channels for reception. For transmission the carrier wave typically is used for segregating a plurality of at least two transmission channels into typically single sideband upper and lower pass bands of baseband bandwidth capability adequately separated with guard bands to permit simple separation for receiving by means of pass band filters, etc.

  4. A multi-radio, multi-hop ad-hoc radio communication network for Communications-Based Train Control (CBTC)

    DEFF Research Database (Denmark)

    Farooq, Jahanzeb; Bro, Lars; Karstensen, Rasmus Thystrup

    2018-01-01

    Communications-Based Train Control (CBTC) is a modern signalling system that uses radio communication to transfer train control information between train and wayside. The trackside networks in these systems are mostly based on conventional infrastructure Wi-Fi (IEEE 802.11). It means a train has ...

  5. Data communication requirements for the advanced NAS network

    Science.gov (United States)

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

    1986-01-01

    The goal of the 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 communications to researchers throughout the United States. The program plan is to continue acquiring the most powerful supercomputers as they become available. In the 1987/1988 time period it is anticipated that a computer with 4 times the processing speed of a Cray 2 will be obtained and by 1990 an additional supercomputer with 16 times the speed of the Cray 2. The implications of this 20-fold increase in processing power on the data communications requirements are described. The analysis was based on models of the projected workload and system architecture. The results are presented together with the estimates of their sensitivity to assumptions inherent in the models.

  6. Performance Analysis of Mobile Ad Hoc Unmanned Aerial Vehicle Communication Networks with Directional Antennas

    Directory of Open Access Journals (Sweden)

    Abdel Ilah Alshbatat

    2010-01-01

    Full Text Available Unmanned aerial vehicles (UAVs have the potential of creating an ad hoc communication network in the air. Most UAVs used in communication networks are equipped with wireless transceivers using omnidirectional antennas. In this paper, we consider a collection of UAVs that communicate through wireless links as a mobile ad-hoc network using directional antennas. The network design goal is to maximize the throughput and minimize the end-to-end delay. In this respect, we propose a new medium access control protocol for a network of UAVs with directional antennas. We analyze the communication channel between the UAVs and the effect of aircraft attitude on the network performance. Using the optimized network engineering tool (OPNET, we compare our protocol with the IEEE 802.11 protocol for omnidirectional antennas. The simulation results show performance improvement in end-to-end delay as well as throughput.

  7. Robust and Cost-Efficient Communication Based on SNMP in Mobile Networks

    Science.gov (United States)

    Ryu, Sang-Hoon; Baik, Doo-Kwon

    A main challenge in the design of this mobile network is the development of dynamic routing protocols that can efficiently find routes between two communicating nodes. Multimedia streaming services are receiving considerable interest in the mobile network business. An entire mobile network may change its point of attachment to the Internet. The mobile network is operated by a basic specification to support network mobility called Network Mobility (NEMO) Basic Support. However, NEMO basic Support mechanism has some problem in continuous communication. In this paper, we propose robust and cost-efficient algorithm. And we simulate proposed method and conclude some remarks.

  8. Optical Communication System for an Underwater Wireless Sensor Network

    Science.gov (United States)

    Gabriel, C.; Khalighi, A.; Bourennane, S.; Léon, P.; Rigaud, V.

    2012-04-01

    Seventy percent of the Earth is covered with water. Yet, we know so little about what lies below the sea surface. One new emerging technology that can help in oceans exploration is underwater wireless sensor network (UWSN). In such a network, a number of sensors are connected to a set of nodes that collect the data from them. Then, each node communicate its retrieved data to the other parts of the network through wireless links. So, an important step in the implementation of an UWSN is the design of an adequate transmitter/receiver system that is reliable, easy to implement, energy efficient and adapted to the underwater environment. Thanks to its cost-effectiveness and low-energy consumption property, optical underwater communication turns to be the most adequate solution for medium range node connections in an UWSN. To evaluate the optical underwater channel, we have studied its impulse response using a Monte Carlo simulator that takes into consideration all the transmitter, receiver and medium characteristics. We have demonstrated through these simulations that the channel delay dispersion is negligible in most practical cases. Therefore, we do not need to perform computationally complex signal processing such as channel equalization at the receiver. After studying the channel characteristics, we have turned our attention onto the transmitter/receiver system design. For this, we have simulated a system composed by a high-power monochromatic 532 nm LED transmitter and a Silicon PIN photodiode receiver with a collimating lens for capturing the scattered light. After photo-detection, the photo-current is converted to a voltage and low-pass filtered to limit the thermal noise variance which is the dominant noise in the receiver. Note that, in our case, background noise can be neglected because we are working in deep waters were the sunlight cannot penetrate. Then, using on-off-keying (OOK) modulation, we have proceeded to signal detection based on optimum

  9. The Effectiveness of Using Social Communications Networks in Mathematics Teachers' Professional Development

    Science.gov (United States)

    Hussein, Hisham Barakat

    2013-01-01

    The study aims to determine the effectiveness of using social communications networks in mathematics teachers' professional development. The main research questions was: what is the effectiveness of using social communications networks in mathematics teachers' professional development. The sub questions were: (1) what are the standards of…

  10. Quantum secure direct communication network with Einstein-Podolsky-Rosen pairs

    International Nuclear Information System (INIS)

    Deng Fuguo; Li Xihan; Li Chunyan; Zhou Ping; Zhou Hongyu

    2006-01-01

    We discuss the four requirements for a real point-to-point quantum secure direct communication (QSDC) first, and then present two efficient QSDC network schemes with an N ordered Einstein-Podolsky-Rosen pairs. Any one of the authorized users can communicate another one on the network securely and directly

  11. Teaching Students How to Integrate and Assess Social Networking Tools in Marketing Communications

    Science.gov (United States)

    Schlee, Regina Pefanis; Harich, Katrin R.

    2013-01-01

    This research is based on two studies that focus on teaching students how to integrate and assess social networking tools in marketing communications. Study 1 examines how students in marketing classes utilize social networking tools and explores their attitudes regarding the use of such tools for marketing communications. Study 2 focuses on an…

  12. Defense Science Board Task Force on Military Satellite Communication and Tactical Networking. Executive Summary

    Science.gov (United States)

    2017-03-01

    Board Task Force on Military Satellite Communication and Tactical Networking.” As a result, the Chairman of the Defense Science Board established a...Force on Military Satellite Communication and Tactical Networking Executive Summary This report is a...product of the Defense Science Board (DSB). The DSB is a Federal Advisory Committee established to provide independent advice to the Secretary of Defense

  13. NASA Near Earth Network (NEN) and Space Network (SN) Support of CubeSat Communications

    Science.gov (United States)

    Schaire, Scott H.; Shaw, Harry C.; Altunc, Serhat; Bussey, George; Celeste, Peter; Kegege, Obadiah; Wong, Yen; Zhang, Yuwen; Patel, Chitra; Raphael, David; hide

    2016-01-01

    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. 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 Telemetry, Tracking and Command (TTC) Systems and Flight Operations for Small Satellites 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, and the potential for high numbers of operational spacecraft. The NASA Space Communications and Navigation (SCaN) Programs Near Earth Network (NEN) and 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). This paper presents how well the SCaN networks, SN and NEN, are currently positioned to support the emerging small small satellite and CubeSat market as well as planned enhancements for future support.

  14. NASA Near Earth Network (NEN) and Space Network (SN) CubeSat Communications

    Science.gov (United States)

    Schaire, Scott H.; Shaw, Harry; Altunc, Serhat; Bussey, George; Celeste, Peter; Kegege, Obadiah; Wong, Yen; Zhang, Yuwen; Patel, Chitra; Raphael, David; hide

    2016-01-01

    There has been a recent trend to increase capability and drive down the Size, Weight and Power (SWAP) of satellites. NASA scientists and engineers across many of NASA's Mission Directorates and Centers are developing exciting CubeSat concepts and welcome potential partnerships for CubeSat endeavors. From a "Telemetry, Tracking and Command (TT&C) Systems and Flight Operations for Small Satellites" 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, and the potential for high numbers of operational spacecraft. The NASA Space Communications and Navigation (SCaN) Program's Near Earth Network (NEN) and Space Network (SN) are customer driven organizations that provide comprehensive communications services for space assets including data transport between a mission's orbiting satellite and its Mission Operations Center (MOC). This paper presents how well the SCaN networks, SN and NEN, are currently positioned to support the emerging small small satellite and CubeSat market as well as planned enhancements for future support.

  15. Intention processing in communication: a common brain network for language and gestures.

    Science.gov (United States)

    Enrici, Ivan; Adenzato, Mauro; Cappa, Stefano; Bara, Bruno G; Tettamanti, Marco

    2011-09-01

    Human communicative competence is based on the ability to process a specific class of mental states, namely, communicative intention. The present fMRI study aims to analyze whether intention processing in communication is affected by the expressive means through which a communicative intention is conveyed, that is, the linguistic or extralinguistic gestural means. Combined factorial and conjunction analyses were used to test two sets of predictions: first, that a common brain network is recruited for the comprehension of communicative intentions independently of the modality through which they are conveyed; second, that additional brain areas are specifically recruited depending on the communicative modality used, reflecting distinct sensorimotor gateways. Our results clearly showed that a common neural network is engaged in communicative intention processing independently of the modality used. This network includes the precuneus, the left and right posterior STS and TPJ, and the medial pFC. Additional brain areas outside those involved in intention processing are specifically engaged by the particular communicative modality, that is, a peri-sylvian language network for the linguistic modality and a sensorimotor network for the extralinguistic modality. Thus, common representation of communicative intention may be accessed by modality-specific gateways, which are distinct for linguistic versus extralinguistic expressive means. Taken together, our results indicate that the information acquired by different communicative modalities is equivalent from a mental processing standpoint, in particular, at the point at which the actor's communicative intention has to be reconstructed.

  16. In-Space Internet-Based Communications for Space Science Platforms Using Commercial Satellite Networks

    Science.gov (United States)

    Kerczewski, Robert J.; Bhasin, Kul B.; Fabian, Theodore P.; Griner, James H.; Kachmar, Brian A.; Richard, Alan M.

    1999-01-01

    The continuing technological advances in satellite communications and global networking have resulted in commercial systems that now can potentially provide capabilities for communications with space-based science platforms. This reduces the need for expensive government owned communications infrastructures to support space science missions while simultaneously making available better service to the end users. An interactive, high data rate Internet type connection through commercial space communications networks would enable authorized researchers anywhere to control space-based experiments in near real time and obtain experimental results immediately. A space based communications network architecture consisting of satellite constellations connecting orbiting space science platforms to ground users can be developed to provide this service. The unresolved technical issues presented by this scenario are the subject of research at NASA's Glenn Research Center in Cleveland, Ohio. Assessment of network architectures, identification of required new or improved technologies, and investigation of data communications protocols are being performed through testbed and satellite experiments and laboratory simulations.

  17. Decentralized Control of Unmanned Aerial Robots for Wireless Airborne Communication Networks

    Directory of Open Access Journals (Sweden)

    Deok-Jin Lee

    2010-09-01

    Full Text Available This paper presents a cooperative control strategy for a team of aerial robotic vehicles to establish wireless airborne communication networks between distributed heterogeneous vehicles. Each aerial robot serves as a flying mobile sensor performing a reconfigurable communication relay node which enabls communication networks with static or slow-moving nodes on gorund or ocean. For distributed optimal deployment of the aerial vehicles for communication networks, an adaptive hill-climbing type decentralized control algorithm is developed to seek out local extremum for optimal localization of the vehicles. The sensor networks estabilished by the decentralized cooperative control approach can adopt its configuraiton in response to signal strength as the function of the relative distance between the autonomous aerial robots and distributed sensor nodes in the sensed environment. Simulation studies are conducted to evaluate the effectiveness of the proposed decentralized cooperative control technique for robust communication networks.

  18. Network coding based joint signaling and dynamic bandwidth allocation scheme for inter optical network unit communication in passive optical networks

    Science.gov (United States)

    Wei, Pei; Gu, Rentao; Ji, Yuefeng

    2014-06-01

    As an innovative and promising technology, network coding has been introduced to passive optical networks (PON) in recent years to support inter optical network unit (ONU) communication, yet the signaling process and dynamic bandwidth allocation (DBA) in PON with network coding (NC-PON) still need further study. Thus, we propose a joint signaling and DBA scheme for efficiently supporting differentiated services of inter ONU communication in NC-PON. In the proposed joint scheme, the signaling process lays the foundation to fulfill network coding in PON, and it can not only avoid the potential threat to downstream security in previous schemes but also be suitable for the proposed hybrid dynamic bandwidth allocation (HDBA) scheme. In HDBA, a DBA cycle is divided into two sub-cycles for applying different coding, scheduling and bandwidth allocation strategies to differentiated classes of services. Besides, as network traffic load varies, the entire upstream transmission window for all REPORT messages slides accordingly, leaving the transmission time of one or two sub-cycles to overlap with the bandwidth allocation calculation time at the optical line terminal (the OLT), so that the upstream idle time can be efficiently eliminated. Performance evaluation results validate that compared with the existing two DBA algorithms deployed in NC-PON, HDBA demonstrates the best quality of service (QoS) support in terms of delay for all classes of services, especially guarantees the end-to-end delay bound of high class services. Specifically, HDBA can eliminate queuing delay and scheduling delay of high class services, reduce those of lower class services by at least 20%, and reduce the average end-to-end delay of all services over 50%. Moreover, HDBA also achieves the maximum delay fairness between coded and uncoded lower class services, and medium delay fairness for high class services.

  19. An Explication and Test of Communication Network Content and Multiplexity as Predictors of Organizational Identification.

    Science.gov (United States)

    Bullis, Connie; Bach, Betsy Wackernagel

    1991-01-01

    Examines the relationship between identification and communication using organizational identification (OI) as a theoretical framework for studying communication networks among incoming graduate students in three university departments of communication. Concludes that, irrespective of initial OI, stronger initial multiplexity predicts the growth…

  20. From Invisible College to Cyberspace College: Computer Conferencing and the Transformation of Informal Scholarly Communication Networks.

    Science.gov (United States)

    Gresham, John L., Jr.

    1994-01-01

    Describes the emergence of the cyberspace college, defined as the informal exchange of scholarly information communicated over informal electronic networks. A history and description of academic computer conferences, results of participant surveys, and the impact of this new communication medium on informal academic communication are discussed.…

  1. Unified Approach to Modeling and Simulation of Space Communication Networks and Systems

    Science.gov (United States)

    Barritt, Brian; Bhasin, Kul; Eddy, Wesley; Matthews, Seth

    2010-01-01

    Network simulator software tools are often used to model the behaviors and interactions of applications, protocols, packets, and data links in terrestrial communication networks. Other software tools that model the physics, orbital dynamics, and RF characteristics of space systems have matured to allow for rapid, detailed analysis of space communication links. However, the absence of a unified toolset that integrates the two modeling approaches has encumbered the systems engineers tasked with the design, architecture, and analysis of complex space communication networks and systems. This paper presents the unified approach and describes the motivation, challenges, and our solution - the customization of the network simulator to integrate with astronautical analysis software tools for high-fidelity end-to-end simulation. Keywords space; communication; systems; networking; simulation; modeling; QualNet; STK; integration; space networks

  2. Research on social communication network evolution based on topology potential distribution

    Science.gov (United States)

    Zhao, Dongjie; Jiang, Jian; Li, Deyi; Zhang, Haisu; Chen, Guisheng

    2011-12-01

    Aiming at the problem of social communication network evolution, first, topology potential is introduced to measure the local influence among nodes in networks. Second, from the perspective of topology potential distribution the method of network evolution description based on topology potential distribution is presented, which takes the artificial intelligence with uncertainty as basic theory and local influence among nodes as essentiality. Then, a social communication network is constructed by enron email dataset, the method presented is used to analyze the characteristic of the social communication network evolution and some useful conclusions are got, implying that the method is effective, which shows that topology potential distribution can effectively describe the characteristic of sociology and detect the local changes in social communication network.

  3. Automatic modulation format recognition for the next generation optical communication networks using artificial neural networks

    Science.gov (United States)

    Guesmi, Latifa; Hraghi, Abir; Menif, Mourad

    2015-03-01

    A new technique for Automatic Modulation Format Recognition (AMFR) in next generation optical communication networks is presented. This technique uses the Artificial Neural Network (ANN) in conjunction with the features of Linear Optical Sampling (LOS) of the detected signal at high bit rates using direct detection or coherent detection. The use of LOS method for this purpose mainly driven by the increase of bit rates which enables the measurement of eye diagrams. The efficiency of this technique is demonstrated under different transmission impairments such as chromatic dispersion (CD) in the range of -500 to 500 ps/nm, differential group delay (DGD) in the range of 0-15 ps and the optical signal tonoise ratio (OSNR) in the range of 10-30 dB. The results of numerical simulation for various modulation formats demonstrate successful recognition from a known bit rates with a higher estimation accuracy, which exceeds 99.8%.

  4. An Accurate Computational Tool for Performance Estimation of FSO Communication Links over Weak to Strong Atmospheric Turbulent Channels

    Directory of Open Access Journals (Sweden)

    Theodore D. Katsilieris

    2017-03-01

    Full Text Available The terrestrial optical wireless communication links have attracted significant research and commercial worldwide interest over the last few years due to the fact that they offer very high and secure data rate transmission with relatively low installation and operational costs, and without need of licensing. However, since the propagation path of the information signal, i.e., the laser beam, is the atmosphere, their effectivity affects the atmospheric conditions strongly in the specific area. Thus, system performance depends significantly on the rain, the fog, the hail, the atmospheric turbulence, etc. Due to the influence of these effects, it is necessary to study, theoretically and numerically, very carefully before the installation of such a communication system. In this work, we present exactly and accurately approximate mathematical expressions for the estimation of the average capacity and the outage probability performance metrics, as functions of the link’s parameters, the transmitted power, the attenuation due to the fog, the ambient noise and the atmospheric turbulence phenomenon. The latter causes the scintillation effect, which results in random and fast fluctuations of the irradiance at the receiver’s end. These fluctuations can be studied accurately with statistical methods. Thus, in this work, we use either the lognormal or the gamma–gamma distribution for weak or moderate to strong turbulence conditions, respectively. Moreover, using the derived mathematical expressions, we design, accomplish and present a computational tool for the estimation of these systems’ performances, while also taking into account the parameter of the link and the atmospheric conditions. Furthermore, in order to increase the accuracy of the presented tool, for the cases where the obtained analytical mathematical expressions are complex, the performance results are verified with the numerical estimation of the appropriate integrals. Finally, using

  5. A HYBRID HOPFIELD NEURAL NETWORK AND TABU SEARCH ALGORITHM TO SOLVE ROUTING PROBLEM IN COMMUNICATION NETWORK

    Directory of Open Access Journals (Sweden)

    MANAR Y. KASHMOLA

    2012-06-01

    Full Text Available The development of hybrid algorithms for solving complex optimization problems focuses on enhancing the strengths and compensating for the weakness of two or more complementary approaches. The goal is to intelligently combine the key elements of these approaches to find superior solutions to solve optimization problems. Optimal routing in communication network is considering a complex optimization problem. In this paper we propose a hybrid Hopfield Neural Network (HNN and Tabu Search (TS algorithm, this algorithm called hybrid HNN-TS algorithm. The paradigm of this hybridization is embedded. We embed the short-term memory and tabu restriction features from TS algorithm in the HNN model. The short-term memory and tabu restriction control the neuron selection process in the HNN model in order to get around the local minima problem and find an optimal solution using the HNN model to solve complex optimization problem. The proposed algorithm is intended to find the optimal path for packet transmission in the network which is fills in the field of routing problem. The optimal path that will be selected is depending on 4-tuples (delay, cost, reliability and capacity. Test results show that the propose algorithm can find path with optimal cost and a reasonable number of iterations. It also shows that the complexity of the network model won’t be a problem since the neuron selection is done heuristically.

  6. Networked Identities: Understanding Different Types of Social Organisation and Movements Between Strong and Weak Ties in Networked Environments

    OpenAIRE

    Ryberg, Thomas; Larsen, Malene Charlotte

    2006-01-01

    In this article we take up a critique of the concept of Communities of Practice voiced by several authors, who suggest that network may provide a better metaphor to understand social forms of organisation and learning. This critique we situate within a broader theoretical movement in socio-cultural learning theories. From this we identify some theoretical and analytical challenges to the network metaphor, which we explore and elaborate through an analysis of a Danish social networking site.

  7. Space Link Extension (SLE) Emulation for High-Throughput Network Communication

    Science.gov (United States)

    Murawski, Robert W.; Tchorowski, Nicole; Golden, Bert

    2014-01-01

    As the data rate requirements for space communications increases, significant stress is placed not only on the wireless satellite communication links, but also on the ground networks which forward data from end-users to remote ground stations. These wide area network (WAN) connections add delay and jitter to the end-to-end satellite communication link, effects which can have significant impacts on the wireless communication link. It is imperative that any ground communication protocol can react to these effects such that the ground network does not become a bottleneck in the communication path to the satellite. In this paper, we present our SCENIC Emulation Lab testbed which was developed to test the CCSDS SLE protocol implementations proposed for use on future NASA communication networks. Our results show that in the presence of realistic levels of network delay, high-throughput SLE communication links can experience significant data rate throttling. Based on our observations, we present some insight into why this data throttling happens, and trace the probable issue back to non-optimal blocking communication which is sup-ported by the CCSDS SLE API recommended practices. These issues were presented as well to the SLE implementation developers which, based on our reports, developed a new release for SLE which we show fixes the SLE blocking issue and greatly improves the protocol throughput. In this paper, we also discuss future developments for our end-to-end emulation lab and how these improvements can be used to develop and test future space communication technologies.

  8. Stochastic Characterization of Communication Network Latency for Wide Area Grid Control Applications.

    Energy Technology Data Exchange (ETDEWEB)

    Ameme, Dan Selorm Kwami [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Guttromson, Ross [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-10-01

    This report characterizes communications network latency under various network topologies and qualities of service (QoS). The characterizations are probabilistic in nature, allowing deeper analysis of stability for Internet Protocol (IP) based feedback control systems used in grid applications. The work involves the use of Raspberry Pi computers as a proxy for a controlled resource, and an ns-3 network simulator on a Linux server to create an experimental platform (testbed) that can be used to model wide-area grid control network communications in smart grid. Modbus protocol is used for information transport, and Routing Information Protocol is used for dynamic route selection within the simulated network.

  9. Scholarly communication in networked environment: problems and prospects

    OpenAIRE

    Vimal Kumar, V.

    2007-01-01

    This article gives an overview of how popularity of World Wide Web and open access concepts challenge the existence of traditional scholarly communication. New publishing outlets such as blogs, wiki and podcasting facilitate agile communication channels for scholarly communication. Open access concepts in scholarly communication enable free access of knowledge. Research community and information professionals hope that scholarly communication through Internet makes available wider access of k...

  10. Social Networking Sites as Communication, Interaction, and Learning Environments: Perceptions and Preferences of Distance Education Students

    Science.gov (United States)

    Bozkurt, Aras; Karadeniz, Abdulkadir; Kocdar, Serpil

    2017-01-01

    The advent of Web 2.0 technologies transformed online networks into interactive spaces in which user-generated content has become the core material. With the possibilities that emerged from Web 2.0, social networking sites became very popular. The capability of social networking sites promises opportunities for communication and interaction,…

  11. A social network approach to understanding science communication among fire professionals

    Science.gov (United States)

    Vita Wright

    2012-01-01

    Studies of science communication and use in the fire management community suggest manager's access research via informal information networks and that these networks vary by both agency and position. We used a phone survey followed by traditional statistical analyses to understand the informal social networks of fire professionals in two western regions of the...

  12. A social network approach to understanding science communication among fire professionals (Abstract)

    Science.gov (United States)

    Vita Wright; Andrea Thode; Anne Mottek-Lucas; Jacklynn Fallon; Megan Matonis

    2012-01-01

    Studies of science communication and use in the fire management community suggest manager's access research via informal information networks and that these networks vary by both agency and position. We used a phone survey followed by traditional statistical analyses to understand the informal social networks of fire professionals in two western regions of the...

  13. Joint Secrecy for D2D Communications Underlying Cellular Networks

    KAUST Repository

    Hyadi, Amal

    2018-01-15

    In this work, we investigate the ergodic secrecy rate region of a block-fading spectrum-sharing system, where a D2D communication is underlying a cellular channel. We consider that both the primary and the secondary transmissions require their respective transmitted messages to be kept secret from a common eavesdropper under a joint secrecy constraint. The presented results are for three different scenarios, each corresponding to a particular requirement of the cellular system. First, we consider the case of a fair cellular system, and we show that the impact of jointly securing the transmissions can be balanced between the primary and the secondary systems. The second scenario examines the case when the primary network is demanding and requires the secondary transmission to be at a rate that is decodable by the primary receiver, while the last scenario assumes a joint transmission of artificial noise by the primary and the secondary transmitters. For each scenario, we present an achievable ergodic secrecy rate region that can be used as an indicator for the cellular and the D2D systems to agree under which terms the spectrum will be shared.

  14. Development of Network Devices Supporting Communication Independence In NPP I and C Systems

    International Nuclear Information System (INIS)

    Jeong, K.-I.; Suh, Y.S.; Park, G.-O.; Park, J.-Y.

    2013-06-01

    As advanced digital I and C systems of nuclear power plants or research reactors are being introduced to replace analog systems, a data communication network is necessary for data exchanges between I and C systems of nuclear power plants or research reactors. Data communication network technology may have significant impact on I and C systems. As the safety I and C system is composed of redundant channels to enhance the performance of the safety functions and data communication system is used to transmit the data generated by the digital I and C systems, communication independence is required to mitigate the risk of safety I and C system failure. Therefore this paper mainly discusses the issues related to the communication independence and the current status of network devices we designed, developed, and validated to satisfy the requirements of function, performance, and communication independence. (authors)

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

    Science.gov (United States)

    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

  16. Using satellite communications for a mobile computer network

    Science.gov (United States)

    Wyman, Douglas J.

    1993-01-01

    The topics discussed include the following: patrol car automation, mobile computer network, network requirements, network design overview, MCN mobile network software, MCN hub operation, mobile satellite software, hub satellite software, the benefits of patrol car automation, the benefits of satellite mobile computing, and national law enforcement satellite.

  17. Digital Networked Information Society and Public Health: Problems and Promises of Networked Health Communication of Lay Publics.

    Science.gov (United States)

    Kim, Jeong-Nam

    2018-01-01

    This special issue of Health Communication compiles 10 articles to laud the promise and yet confront the problems in the digital networked information society related to public health. We present this anthology of symphony and cacophony of lay individuals' communicative actions in a digital networked information society. The collection of problems and promise of the new digital world may be a cornerstone joining two worlds-pre- and postdigital network society-and we hope this special issue will help better shape our future states of public health.

  18. Simulation technologies in networking and communications selecting the best tool for the test

    CERN Document Server

    Pathan, Al-Sakib Khan; Khan, Shafiullah

    2014-01-01

    Simulation is a widely used mechanism for validating the theoretical models of networking and communication systems. Although the claims made based on simulations are considered to be reliable, how reliable they really are is best determined with real-world implementation trials.Simulation Technologies in Networking and Communications: Selecting the Best Tool for the Test addresses the spectrum of issues regarding the different mechanisms related to simulation technologies in networking and communications fields. Focusing on the practice of simulation testing instead of the theory, it presents

  19. Cooperative device-to-device communication in cognitive radio cellular networks

    CERN Document Server

    Li, Peng

    2014-01-01

    This brief examines current research on cooperative device-to-device (D2D) communication as an enhanced offloading technology to improve the performance of cognitive radio cellular networks. By providing an extensive review of recent advances in D2D communication, the authors demonstrate that the quality of D2D links significantly affects offloading performance in cellular networks, which motivates the design of cooperative D2D communication. After presenting the architecture of cooperative D2D communication, the challenges of capacity maximization and energy efficiency are addressed by optimi

  20. High-Speed Optical Wide-Area Data-Communication Network

    Science.gov (United States)

    Monacos, Steve P.

    1994-01-01

    Proposed fiber-optic wide-area network (WAN) for digital communication balances input and output flows of data with its internal capacity by routing traffic via dynamically interconnected routing planes. Data transmitted optically through network by wavelength-division multiplexing in synchronous or asynchronous packets. WAN implemented with currently available technology. Network is multiple-ring cyclic shuffle exchange network ensuring traffic reaches its destination with minimum number of hops.

  1. [Principles and stakes of external communication of healthcare networks: the case of heathcare networks for health services accessibility].

    Science.gov (United States)

    Plu, Isabelle; Gignon, Maxime; Emery, Sophie; Purssell-François, Irène; Moutel, Grégoire; Hervé, Christian

    2009-01-01

    Healthcare networks which purpose is to manage patients through better coordination of the care, need to develop a communication strategy to be recognized by the public and by healthcare professionals and to be inserted in the healthcare landscape. We firstly will present legal requirements related to external communication of healthcare networks. Then, we will describe the different tools which can be used to communicate about healthcare networks in its area, with the example from a healthcare network for health services accessibility. In the French Public health code, the legal status and the ethical charter of the healthcare network have to be delivered to the healthcare professionals in its area and to the patients. Moreover, the example healthcare network informed collectively and individually the healthcare professionals of its area about its activities. It made it known to the public by the way of departmental prevention manifestations and health education sessions in community social associations. From these examples, we will conduct an ethical reflection on the modalities and stakes of the external communication of healthcare networks.

  2. A Novel Dual Separate Paths (DSP) Algorithm Providing Fault-Tolerant Communication for Wireless Sensor Networks.

    Science.gov (United States)

    Tien, Nguyen Xuan; Kim, Semog; Rhee, Jong Myung; Park, Sang Yoon

    2017-07-25

    Fault tolerance has long been a major concern for sensor communications in fault-tolerant cyber physical systems (CPSs). Network failure problems often occur in wireless sensor networks (WSNs) due to various factors such as the insufficient power of sensor nodes, the dislocation of sensor nodes, the unstable state of wireless links, and unpredictable environmental interference. Fault tolerance is thus one of the key requirements for data communications in WSN applications. This paper proposes a novel path redundancy-based algorithm, called dual separate paths (DSP), that provides fault-tolerant communication with the improvement of the network traffic performance for WSN applications, such as fault-tolerant CPSs. The proposed DSP algorithm establishes two separate paths between a source and a destination in a network based on the network topology information. These paths are node-disjoint paths and have optimal path distances. Unicast frames are delivered from the source to the destination in the network through the dual paths, providing fault-tolerant communication and reducing redundant unicast traffic for the network. The DSP algorithm can be applied to wired and wireless networks, such as WSNs, to provide seamless fault-tolerant communication for mission-critical and life-critical applications such as fault-tolerant CPSs. The analyzed and simulated results show that the DSP-based approach not only provides fault-tolerant communication, but also improves network traffic performance. For the case study in this paper, when the DSP algorithm was applied to high-availability seamless redundancy (HSR) networks, the proposed DSP-based approach reduced the network traffic by 80% to 88% compared with the standard HSR protocol, thus improving network traffic performance.

  3. Local empathy provides global minimization of congestion in communication networks

    Science.gov (United States)

    Meloni, Sandro; Gómez-Gardeñes, Jesús

    2010-11-01

    We present a mechanism to avoid congestion in complex networks based on a local knowledge of traffic conditions and the ability of routers to self-coordinate their dynamical behavior. In particular, routers make use of local information about traffic conditions to either reject or accept information packets from their neighbors. We show that when nodes are only aware of their own congestion state they self-organize into a hierarchical configuration that delays remarkably the onset of congestion although leading to a sharp first-order-like congestion transition. We also consider the case when nodes are aware of the congestion state of their neighbors. In this case, we show that empathy between nodes is strongly beneficial to the overall performance of the system and it is possible to achieve larger values for the critical load together with a smooth, second-order-like, transition. Finally, we show how local empathy minimize the impact of congestion as much as global minimization. Therefore, here we present an outstanding example of how local dynamical rules can optimize the system’s functioning up to the levels reached using global knowledge.

  4. Technical Note: Novel method for water vapour monitoring using wireless communication networks measurements

    Directory of Open Access Journals (Sweden)

    N. David

    2009-04-01

    Full Text Available We propose a new technique that overcomes the obstacles of the existing methods for monitoring near-surface water vapour, by estimating humidity from data collected through existing wireless communication networks.

    Weather conditions and atmospheric phenomena affect the electromagnetic channel, causing attenuations to the radio signals. Thus, wireless communication networks are in effect built-in environmental monitoring facilities. The wireless microwave links, used in these networks, are widely deployed by cellular providers for backhaul communication between base stations, a few tens of meters above ground level. As a result, if all available measurements are used, the proposed method can provide moisture observations with high spatial resolution and potentially high temporal resolution. Further, the implementation cost is minimal, since the data used are already collected and saved by the cellular operators. In addition – many of these links are installed in areas where access is difficult such as orographic terrain and complex topography. As such, our method enables measurements in places that have been hard to measure in the past, or have never been measured before. The technique is restricted to weather conditions which exclude rain, fog or clouds along the propagation path. Strong winds that may cause movement of the link transmitter or receiver (or both may also interfere with the ability to conduct accurate measurements.

    We present results from real-data measurements taken from two microwave links used in a backhaul cellular network that show convincing correlation to surface station humidity measurements. The measurements were taken daily in two sites, one in northern Israel (28 measurements, the other in central Israel (29 measurements. The correlation between the microwave link measurements and the humidity gauges were 0.9 and 0.82 for the north and central sites, respectively. The Root Mean Square Differences

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    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. (paper)

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

    Science.gov (United States)

    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.

  7. Second language social networks and communication-related acculturative stress: The role of interconnectedness

    Directory of Open Access Journals (Sweden)

    Marina M Doucerain

    2015-08-01

    Full Text Available Although a substantial amount of cross-cultural psychology research has investigated acculturative stress in general, little attention has been devoted specifically to communication-related acculturative stress. In line with the view that cross-cultural adaptation and second language (L2 learning are social and interpersonal phenomena, the present study examines the hypothesis that migrants' L2 social network size and interconnectedness predict communication-related acculturative stress. The main idea underlying this hypothesis is that L2 social networks play an important role in fostering social and cultural aspects of communicative competence. Specifically, higher interconnectedness may reflect greater access to unmodified natural cultural representations and L2 communication practices, thus fostering communicative competence through observational learning. As such, structural aspects of migrants' L2 social networks may be protective against acculturative stress arising from chronic communication difficulties. Results from a study of first generation migrant students (N=100 support this idea by showing that both inclusiveness and density of the participants' L2 network account for unique variance in communication-related acculturative stress but not in general acculturative stress. These results support the idea that research on cross-cultural adaptation would benefit from disentangling the various facets of acculturative stress and that the structure of migrants' L2 network matters for language related outcomes. Finally, this study contributes to an emerging body of work that attempts to integrate cultural/cross-cultural research on acculturation and research on intercultural communication and second language learning.

  8. Till stress do us part: On the interplay between perceived stress and communication network dynamics.

    Science.gov (United States)

    Kalish, Yuval; Luria, Gil; Toker, Sharon; Westman, Mina

    2015-11-01

    This study of perceived stress and communication networks fills 2 theoretical gaps in the literature: First, drawing predominantly on conservation of resource theory and faultline theory, we demonstrate the role of stress as an "engine of action" in network evolution. Second, we extend the stress literature to the interpersonal domain by arguing that others' levels of stress influence the individual's communication network, and this, in turn, changes his or her stress level. At 3 time points, we evaluated the communication ties and perceived stress in a unique field setting comprising 115 male participants (in 6 groups) performing group-based tasks. We introduce stochastic actor-based models for the coevolution of network ties and actor attributes, statistical models that enable causal inferences to be drawn regarding the interplay between dynamic networks and individual attributes. Using these models, we find that over time, individuals experiencing higher levels of perceived stress were less likely to create new communication ties and were more likely to maintain existing ties to others. Participants also tended to communicate with similarly stressed others. Such communication network dynamics further increased individuals' levels of perceived stress over time, leading to stress-related vicious cycles. We discuss organizational implications that relate to stress and network-related interventions. (c) 2015 APA, all rights reserved).

  9. Proceedings of the Workshop on Advanced Network and Technology Concepts for Mobile, Micro, and Personal Communications

    Science.gov (United States)

    Paul, Lori (Editor)

    1991-01-01

    The Workshop on Advanced Network and Technology Concepts for Mobile, Micro, and Personal Communications was held at NASA's JPL Laboratory on 30-31 May 1991. It provided a forum for reviewing the development of advanced network and technology concepts for turn-of-the-century telecommunications. The workshop was organized into three main categories: (1) Satellite-Based Networks (L-band, C-band, Ku-band, and Ka-band); (2) Terrestrial-Based Networks (cellular, CT2, PCN, GSM, and other networks); and (3) Hybrid Satellite/Terrestrial Networks. The proceedings contain presentation papers from each of the above categories.

  10. Mechanically Strong Double Network Photocrosslinked Hydrogels from N, N-Dimethylacrylamide and Glycidyl Methacrylated Hyaluronan

    Science.gov (United States)

    Weng, Lihui; Gouldstone, Andrew; Wu, Yuhong; Chen, Weiliam

    2008-01-01

    Hyaluronan (HA) is a natural polysaccharide abundant in biological tissues and it can be modified to prepare biomaterials. In this work, HA modified with glycidyl methacrylate was photocrosslinked to form the first network (PHA), and then a series of highly porous PHA/N, N-dimethylacrylamide (DAAm) hydrogels (PHA/DAAm) with high mechanical strength were obtained by incorporating a second network of photocrosslinked DAAm into PHA network. Due to synergistic effect produced by double network (DN) structure, despite containing 90% of water, the resulting PHA/DAAm hydrogel showed a compressive modulus and a fracture stress over 0.5 MPa and 5.2 MPa, respectively. Compared to the photocrosslinked hyaluronan single network hydrogel, which is generally very brittle and fractures easily, the PHA/DAAm hydrogels are ductile. Mouse dermal fibroblast was used as a model cell line to validate in vitro non-cytotoxicity of the PHA/DAAm hydrogels. Cells deposited extracellular matrix on the surface of these hydrogels and this was confirmed by positive staining of Type I collagen by Sirius Red. The PHA/DAAm hydrogels were also resistant to biodegradation and largely retained their excellent mechanical properties even after two months of co-culturing with fibroblasts. PMID:18272215

  11. A Hybrid Communications Network Simulation-Independent Toolkit

    National Research Council Canada - National Science Library

    Dines, David M

    2008-01-01

    .... Evolving a grand design of the enabling network will require a flexible evaluation platform to try and select the right combination of network strategies and protocols in the realms of topology control and routing...

  12. Adaptive routing in wireless communication networks using swarm intelligence

    Science.gov (United States)

    Arabshahi, P.; Gray, A.; Kassabalidis, I.; Das, A.; Narayanan, S.; Sharkawi, M. El; Marks, R. J.

    2001-01-01

    In this paper we focus on the network routing problem, and survey swarm intelligent approaches for its efficient solution, after a brief overview of power-aware routing schemes, which are important in the network examples outlined above.

  13. Dynamic communications for small satellites using disruption tolerant network concepts

    OpenAIRE

    Giuditta, N.; Gill, E.K.A.; Fernández, B.; Isaac, D.

    2009-01-01

    New network technologies are providing interconnectivity in areas previously unheard of. One of these novel technologies, named Disruption Tolerant Networking (DTN), shows promise for the space industry. In order to study its suitability for University projects, a model of a University space mission has been created using network simulation software. This offers an insight into the characteristics, opportunities and challenges of this new technology. Disruption Tolerant Networking is a pionee...

  14. Inferring Social Relations from Online and Communication Networks

    OpenAIRE

    Nasim, Mehwish

    2016-01-01

    In this work analyzed the interplay between social relations in the form of friendship ties, attributes and interaction in online social networks. In this context we analyzed composition of social circles in online social networks and showed that social circles are homophilious with respect to at least one node attribute. We showed that using the right combination of network and interaction features, links can be inferred in online covert networks. We also analyzed longitudinal dyadic interac...

  15. Communication Delays in the Cooperative Control of Wide Area Search Munitions Via Iterative Network Flow

    National Research Council Canada - National Science Library

    Mitchell, Jason

    2003-01-01

    .... This model is used to study the effect of communication delays on the performance of an iteractive network flow optimization model that results in a sequence of linear programs for the optimal...

  16. Communication, opponents, and clan performance in online games: a social network approach.

    Science.gov (United States)

    Lee, Hong Joo; Choi, Jaewon; Kim, Jong Woo; Park, Sung Joo; Gloor, Peter

    2013-12-01

    Online gamers form clans voluntarily to play together and to discuss their real and virtual lives. Although these clans have diverse goals, they seek to increase their rank in the game community by winning more battles. Communications among clan members and battles with other clans may influence the performance of a clan. In this study, we compared the effects of communication structure inside a clan, and battle networks among clans, with the performance of the clans. We collected battle histories, posts, and comments on clan pages from a Korean online game, and measured social network indices for communication and battle networks. Communication structures in terms of density and group degree centralization index had no significant association with clan performance. However, the centrality of clans in the battle network was positively related to the performance of the clan. If a clan had many battle opponents, the performance of the clan improved.

  17. FY 1999 Blue Book: Computing, Information, and Communications: Networked Computing for the 21st Century

    Data.gov (United States)

    Networking and Information Technology Research and Development, Executive Office of the President — U.S.research and development R and D in computing, communications, and information technologies has enabled unprecedented scientific and engineering advances,...

  18. A synthetic mammalian network to compute population borders based on engineered reciprocal cell-cell communication.

    Science.gov (United States)

    Kolar, Katja; Wischhusen, Hanna M; Müller, Konrad; Karlsson, Maria; Weber, Wilfried; Zurbriggen, Matias D

    2015-12-30

    Multicellular organisms depend on the exchange of information between specialized cells. This communication is often difficult to decipher in its native context, but synthetic biology provides tools to engineer well-defined systems that allow the convenient study and manipulation of intercellular communication networks. Here, we present the first mammalian synthetic network for reciprocal cell-cell communication to compute the border between a sender/receiver and a processing cell population. The two populations communicate via L-tryptophan and interleukin-4 to highlight the population border by the production of a fluorescent protein. The sharpness of that visualized edge can be adjusted by modulating key parameters of the network. We anticipate that this network will on the one hand be a useful tool to gain deeper insights into the mechanisms of tissue formation in nature and will on the other hand contribute to our ability to engineer artificial tissues.

  19. Asynchronous Free-Space Optical CDMA Communications System for Last-mile Access Network

    DEFF Research Database (Denmark)

    Jurado-Navas, Antonio; Raddo, Thiago R.; Sanches, Anderson L.

    2016-01-01

    We propose a new hybrid asynchronous OCDMA-FSO communications system for access network solutions. New ABER expressions are derived under gamma-gamma scintillation channels, where all users can surprisingly achieve error-free transmissions when FEC is employed....

  20. Beyond Traditional DTN Routing: Social Networks for Opportunistic Communication

    OpenAIRE

    Schurgot, Mary R.; Comaniciu, Cristina; Jaffrès-Runser, Katia

    2011-01-01

    This article examines the evolution of routing protocols for intermittently connected ad hoc networks and discusses the trend toward social-based routing protocols. A survey of current routing solutions is presented, where routing protocols for opportunistic networks are classified based on the network graph employed. The need to capture performance tradeoffs from a multi-objective perspective is highlighted.

  1. Cooperation in Social Networks: Communication, Trust, and Selflessness

    Science.gov (United States)

    2008-12-01

    The Army’s myriad social networks connect not only humans and soldiers, but also machines, computers, and robots. And most of the social/biological...cooperation can be precisely defined. We demonstrate how the framework can be applied to social networks , and examine the dynamic networks arising in

  2. Wi-Fi Network Communication Technology Design | Onibere ...

    African Journals Online (AJOL)

    Transmission media (like Satellite, VSAT), access method used to transmit both voice and data on the networks and underlying software and hardware requirements. Also the various standards and protocol for proper wireless networks management, the various authentication and encryption techniques of Wi -Fi network ...

  3. Communications Training Courses Across the Leopold Leadership Network

    Science.gov (United States)

    Hayden, T.; Gerber, L. R.; Silver, W. L.

    2012-12-01

    For nearly fifteen years, the Leopold Leadership Program has provided science communication training and support to mid-career academic environmental researchers from across North America. There has been an emphasis throughout on effective communication to non-scientific audiences. Increasingly, Leopold fellows have been developing communications courses for their own students, responding to the need for future scientists to be able to communicate well with the public, the media, policy makers and other audiences. At a June 2012 reunion meeting, a group of past fellows and communications trainers conducted a curriculum exchange, sharing experiences and ideas for successful inclusion of communications training in environmental science curricula. This presentation will present case studies from several institutions, including the use of podcasting, web columns, social media, in-person presentation and other presentation styles for connecting general audiences. We will share best practices, challenges and recommendations for curriculum development and institutional acceptance.

  4. Social Networking Among Youth and Their Communication and Conflict Resolution Skills

    OpenAIRE

    Mistry DR; Verma M; Vyas SN; Kantharia SL

    2014-01-01

    Introduction: New digital media have dramatically altered the communication landscape, especially for youth. “Indian web users spend 26 minutes online each day”. This study is concerned with effect of social networking on youth regarding potential risk, safety, wellbeing & skill development because they are still maturing & forming the ability to attain & implement communication & conflict resolution skill on interpersonal level. Aim & objective: To explore the impact of social networking on ...

  5. [Communication management of collaborative networks of science, technology and innovation in health].

    Science.gov (United States)

    Martins, Wagner de Jesus; Artmann, Elizabeth; Rivera, Francisco Javier Uribe

    2012-12-01

    The objective of the article was to propose a model of communication management of networks for the Health Innovation System in Brazil. The health production complex and its relationship with the nation's development are addressed and some suggestions for operationalization of the proposed model are also presented. The discussion is based on Habermas' theory and similar cases from other countries. Communication strategies and approaches to commitment dialogue for concerted actions and consensus-building based on critical reasoning may help strengthen democratic networks.

  6. Faithful qubit transmission in a quantum communication network with heterogeneous channels

    Science.gov (United States)

    Chen, Na; Zhang, Lin Xi; Pei, Chang Xing

    2018-04-01

    Quantum communication networks enable long-distance qubit transmission and distributed quantum computation. In this paper, a quantum communication network with heterogeneous quantum channels is constructed. A faithful qubit transmission scheme is presented. Detailed calculations and performance analyses show that even in a low-quality quantum channel with serious decoherence, only modest number of locally prepared target qubits are required to achieve near-deterministic qubit transmission.

  7. Effect of inter-fibre bonding on the fracture of fibrous networks with strong interactions

    DEFF Research Database (Denmark)

    Goutianos, Stergios; Mao, Rui; Peijs, Ton

    2017-01-01

    Abstract The mechanical response of cellulose nanopaper composites is investigated using a three-dimensional (3D) finite element fibrous network model with focus on the effect of inter-fibre bonds. It is found that the Young’s modulus and strength, for fixed fibre properties, are mainly controlle...

  8. Power-law behavior in complex organizational communication networks during crisis

    Science.gov (United States)

    Uddin, Shahadat; Murshed, Shahriar Tanvir Hasan; Hossain, Liaquat

    2011-08-01

    Communication networks can be described as patterns of contacts which are created due to the flow of messages and information shared among participating actors. Contemporary organizations are now commonly viewed as dynamic systems of adaptation and evolution containing several parts, which interact with one another both in internal and in external environment. Although there is limited consensus among researchers on the precise definition of organizational crisis, there is evidence of shared meaning: crisis produces individual crisis, crisis can be associated with positive or negative conditions, crises can be situations having been precipitated quickly or suddenly or situations that have developed over time and are predictable etc. In this research, we study the power-law behavior of an organizational email communication network during crisis from complexity perspective. Power law simply describes that, the probability that a randomly selected node has k links (i.e. degree k) follows P(k)∼k, where γ is the degree exponent. We used social network analysis tools and techniques to analyze the email communication dataset. We tested two propositions: (1) as organization goes through crisis, a few actors, who are prominent or more active, will become central, and (2) the daily communication network as well as the actors in the communication network exhibit power-law behavior. Our preliminary results support these two propositions. The outcome of this study may provide significant advancement in exploring organizational communication network behavior during crisis.

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

    Science.gov (United States)

    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.

  10. 77 FR 36305 - Stream Communications Network & Media, Inc.; Order of Suspension of Trading

    Science.gov (United States)

    2012-06-18

    ... SECURITIES AND EXCHANGE COMMISSION [File No. 500-1] Stream Communications Network & Media, Inc.; Order of Suspension of Trading June 14, 2012. It appears to the Securities and Exchange Commission that there is a lack of current and accurate information concerning the securities of Stream Communications...

  11. Inter-organisational communication networks in healthcare: centralised versus decentralised approaches

    NARCIS (Netherlands)

    H. Pirnejad (Habibollah); R.A. Bal (Roland); A. Stoop; M. Berg (Marc)

    2007-01-01

    textabstractBackground: To afford efficient and high quality care, healthcare providers increasingly need to exchange patient data. The existence of a communication network amongst care providers will help them to exchange patient data more efficiently. Information and communication technology (ICT)

  12. Signal Quality Outage Analysis for Ultra-Reliable Communications in Cellular Networks

    DEFF Research Database (Denmark)

    Gerardino, Guillermo Andrés Pocovi; Alvarez, Beatriz Soret; Lauridsen, Mads

    2015-01-01

    Ultra-reliable communications over wireless will open the possibility for a wide range of novel use cases and applications. In cellular networks, achieving reliable communication is challenging due to many factors, particularly the fading of the desired signal and the interference. In this regard...

  13. Packet Traffic Dynamics Near Onset of Congestion in Data Communication Network Model

    Science.gov (United States)

    Lawniczak, A. T.; Tang, X.

    2006-05-01

    The dominant technology of data communication networks is the Packet Switching Network (PSN). It is a complex technology organized as various hierarchical layers according to the International Standard Organization (ISO) Open Systems Interconnect (OSI) Reference Model. The Network Layer of the ISO OSI Reference Model is responsible for delivering packets from their sources to their destinations and for dealing with congestion if it arises in a network. Thus, we focus on this layer and present an abstraction of the Network Layer of the ISO OSI Reference Model. Using this abstraction we investigate how onset of traffic congestion is affected for various routing algorithms by changes in network connection topology. We study how aggregate measures of network performance depend on network connection topology and routing. We explore packets traffic spatio-temporal dynamics near the phase transition point from free flow to congestion for various network connection topologies and routing algorithms. We consider static and adaptive routings. We present selected simulation results.

  14. Fiber-wireless convergence in next-generation communication networks systems, architectures, and management

    CERN Document Server

    Chang, Gee-Kung; Ellinas, Georgios

    2017-01-01

    This book investigates new enabling technologies for Fi-Wi convergence. The editors discuss Fi-Wi technologies at the three major network levels involved in the path towards convergence: system level, network architecture level, and network management level. The main topics will be: a. At system level: Radio over Fiber (digitalized vs. analogic, standardization, E-band and beyond) and 5G wireless technologies; b. Network architecture level: NGPON, WDM-PON, BBU Hotelling, Cloud Radio Access Networks (C-RANs), HetNets. c. Network management level: SDN for convergence, Next-generation Point-of-Presence, Wi-Fi LTE Handover, Cooperative MultiPoint. • Addresses the Fi-Wi convergence issues at three different levels, namely at the system level, network architecture level, and network management level • Provides approaches in communication systems, network architecture, and management that are expected to steer the evolution towards fiber-wireless convergence • Contributions from leading experts in the field of...

  15. Providing strong Security and high privacy in low-cost RFID networks

    DEFF Research Database (Denmark)

    David, Mathieu; Prasad, Neeli R.

    2009-01-01

    Since the dissemination of Radio Frequency IDentification (RFID) tags is getting larger and larger, the requirement for strong security and privacy is also increasing. Low-cost and ultra-low-cost tags are being implemented on everyday products, and their limited resources constraints the security...... algorithms to be designed especially for those tags. In this paper, a complete solution providing strong security and high privacy during the whole product lifetime is presented. Combining bit-wise operations and secret keys, the algorithm proposed addresses and solves all the common security attacks....

  16. <strong>Application of risk perception and communication strategies to manage disease outbreaks of coastal shrimp farming in developing countriesstrong>

    DEFF Research Database (Denmark)

    Ahsan, Dewan

    2008-01-01

      Risk and uncertainty are very common issues in coastal shrimp industry like in any other business. A variety of risks are associated in shrimp farming like, production risks, technical risks, economical risks and disease of shrimp. However, risk of economic losses due to shrimp mortality (for...... diseases) is the major concern of shrimp producers of developing countries like Bangladesh, India, Thailand, China and many other countries. The risk of disease outbreaks in shrimp farms could be effectively prevented and managed by early identification of disease occurrence and by rapid communication...

  17. Verifying cell loss requirements in high-speed communication networks

    Directory of Open Access Journals (Sweden)

    Kerry W. Fendick

    1998-01-01

    Full Text Available In high-speed communication networks it is common to have requirements of very small cell loss probabilities due to buffer overflow. Losses are measured to verify that the cell loss requirements are being met, but it is not clear how to interpret such measurements. We propose methods for determining whether or not cell loss requirements are being met. A key idea is to look at the stream of losses as successive clusters of losses. Often clusters of losses, rather than individual losses, should be regarded as the important “loss events”. Thus we propose modeling the cell loss process by a batch Poisson stochastic process. Successive clusters of losses are assumed to arrive according to a Poisson process. Within each cluster, cell losses do not occur at a single time, but the distance between losses within a cluster should be negligible compared to the distance between clusters. Thus, for the purpose of estimating the cell loss probability, we ignore the spaces between successive cell losses in a cluster of losses. Asymptotic theory suggests that the counting process of losses initiating clusters often should be approximately a Poisson process even though the cell arrival process is not nearly Poisson. The batch Poisson model is relatively easy to test statistically and fit; e.g., the batch-size distribution and the batch arrival rate can readily be estimated from cell loss data. Since batch (cluster sizes may be highly variable, it may be useful to focus on the number of batches instead of the number of cells in a measurement interval. We also propose a method for approximately determining the parameters of a special batch Poisson cell loss with geometric batch-size distribution from a queueing model of the buffer content. For this step, we use a reflected Brownian motion (RBM approximation of a G/D/1/C queueing model. We also use the RBM model to estimate the input burstiness given the cell loss rate. In addition, we use the RBM model to

  18. Power Terminal Communication Access Network Monitoring System Scheme Based on Design Patterns

    Science.gov (United States)

    Yan, Shengchao; Wu, Desheng; Zhu, Jiang

    2018-01-01

    In order to realize patterns design for terminal communication monitoring system, this paper introduces manager-workers, tasks-workers design patterns, based on common design patterns such as factory method, chain of responsibility, facade. Using these patterns, the communication monitoring system which combines module-groups like networking communication, business data processing and the peripheral support has been designed successfully. Using these patterns makes this system have great flexibility and scalability and improves the degree of systematic pattern design structure.

  19. Effects of strong network modifiers on Fe3+/Fe2+ in silicate melts: an experimental study

    Science.gov (United States)

    Borisov, Alexander; Behrens, Harald; Holtz, Francois

    2017-05-01

    The effect of CaO, Na2O, and K2O on ferric/ferrous ratio in model multicomponent silicate melts was investigated in the temperature range 1450-1550 °C at 1-atm total pressure in air. It is demonstrated that the addition of these network modifier cations results in an increase of Fe3+/Fe2+ ratio. The influence of network modifier cations on the ferric/ferrous ratio increases in the order Ca SiO2-TiO2-Al2O3-FeO-Fe2O3-MgO-CaO-Na2O-K2O-P2O5 melts at air conditions.

  20. Strong geomagnetic activity forecast by neural networks under dominant southern orientation of the interplanetary magnetic field

    Czech Academy of Sciences Publication Activity Database

    Valach, F.; Bochníček, Josef; Hejda, Pavel; Revallo, M.

    2014-01-01

    Roč. 53, č. 4 (2014), s. 589-598 ISSN 0273-1177 R&D Projects: GA AV ČR(CZ) IAA300120608; GA MŠk OC09070 Institutional support: RVO:67985530 Keywords : geomagnetic activity * interplanetary magnetic field * artificial neural network * ejection of coronal mass * X-ray flares Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 1.358, year: 2014

  1. Criteria for Evaluating Alternative Network and Link Layer Protocols for the NASA Constellation Program Communication Architecture

    Science.gov (United States)

    Benbenek, Daniel; Soloff, Jason; Lieb, Erica

    2010-01-01

    Selecting a communications and network architecture for future manned space flight requires an evaluation of the varying goals and objectives of the program, development of communications and network architecture evaluation criteria, and assessment of critical architecture trades. This paper uses Cx Program proposed exploration activities as a guideline; lunar sortie, outpost, Mars, and flexible path options are described. A set of proposed communications network architecture criteria are proposed and described. They include: interoperability, security, reliability, and ease of automating topology changes. Finally a key set of architecture options are traded including (1) multiplexing data at a common network layer vs. at the data link layer, (2) implementing multiple network layers vs. a single network layer, and (3) the use of a particular network layer protocol, primarily IPv6 vs. Delay Tolerant Networking (DTN). In summary, the protocol options are evaluated against the proposed exploration activities and their relative performance with respect to the criteria are assessed. An architectural approach which includes (a) the capability of multiplexing at both the network layer and the data link layer and (b) a single network layer for operations at each program phase, as these solutions are best suited to respond to the widest array of program needs and meet each of the evaluation criteria.

  2. Network analysis reveals strongly localized impacts of El Niño

    Science.gov (United States)

    Fan, Jingfang; Meng, Jun; Ashkenazy, Yosef; Havlin, Shlomo; Schellnhuber, Hans Joachim

    2017-07-01

    Climatic conditions influence the culture and economy of societies and the performance of economies. Specifically, El Niño as an extreme climate event is known to have notable effects on health, agriculture, industry, and conflict. Here, we construct directed and weighted climate networks based on near-surface air temperature to investigate the global impacts of El Niño and La Niña. We find that regions that are characterized by higher positive/negative network “in”-weighted links are exhibiting stronger correlations with the El Niño basin and are warmer/cooler during El Niño/La Niña periods. In contrast to non-El Niño periods, these stronger in-weighted activities are found to be concentrated in very localized areas, whereas a large fraction of the globe is not influenced by the events. The regions of localized activity vary from one El Niño (La Niña) event to another; still, some El Niño (La Niña) events are more similar to each other. We quantify this similarity using network community structure. The results and methodology reported here may be used to improve the understanding and prediction of El Niño/La Niña events and also may be applied in the investigation of other climate variables.

  3. Communications network design and costing model technical manual

    Science.gov (United States)

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

    1983-01-01

    This computer model provides the capability for analyzing long-haul trunking networks comprising a set of user-defined cities, traffic conditions, and tariff rates. Networks may consist of all terrestrial connectivity, all satellite connectivity, or a combination of terrestrial and satellite connectivity. Network solutions provide the least-cost routes between all cities, the least-cost network routing configuration, and terrestrial and satellite service cost totals. The CNDC model allows analyses involving three specific FCC-approved tariffs, which are uniquely structured and representative of most existing service connectivity and pricing philosophies. User-defined tariffs that can be variations of these three tariffs are accepted as input to the model and allow considerable flexibility in network problem specification. The resulting model extends the domain of network analysis from traditional fixed link cost (distance-sensitive) problems to more complex problems involving combinations of distance and traffic-sensitive tariffs.

  4. Implementation of a communication and control network for the instruments of a nuclear analytical laboratory

    International Nuclear Information System (INIS)

    Cunya, Eduardo; Baltuano, Oscar; Bedregal, Patricia

    2013-01-01

    This paper describes the implementation of a communication network and control for a conventional laboratory instruments and nuclear analytical processes based on CAN open field bus to control devices and machines. Hardware components and software developed as well as installation and configuration tools for incorporating new instruments to the network re presented. (authors).

  5. The Use of Social Networks as a Communication Tool between Teachers and Students: A Literature Review

    Science.gov (United States)

    Froment, Facundo; García González, Alfonso Javier; Bohórquez, M. Rocío

    2017-01-01

    Social networks have drastically changed communication between people, constituting a means of everyday use by which information is created and shared in a simple, instantaneous way with the rest of the world. Although social networks were not initially created for academic purposes, they are gradually being used as a means of communication…

  6. Fluid Centrality: A Social Network Analysis of Social-Technical Relations in Computer-Mediated Communication

    Science.gov (United States)

    Enriquez, Judith Guevarra

    2010-01-01

    In this article, centrality is explored as a measure of computer-mediated communication (CMC) in networked learning. Centrality measure is quite common in performing social network analysis (SNA) and in analysing social cohesion, strength of ties and influence in CMC, and computer-supported collaborative learning research. It argues that measuring…

  7. LAN Configuration and Analysis: Projects for the Data Communications and Networking Course

    Science.gov (United States)

    Chen, Fang; Brabston, Mary

    2011-01-01

    We implemented two local area network (LAN) projects in our introductory data communications and networking course. The first project required students to develop a LAN from scratch for a small imaginary organization. The second project required student groups to analyze a LAN for a real world small organization. By allowing students to apply what…

  8. Adolescent Peer Relationships and Behavior Problems Predict Young Adults' Communication on Social Networking Websites

    Science.gov (United States)

    Mikami, Amori Yee; Szwedo, David E.; Allen, Joseph P.; Evans, Meredyth A.; Hare, Amanda L.

    2010-01-01

    This study examined online communication on social networking web pages in a longitudinal sample of 92 youths (39 male, 53 female). Participants' social and behavioral adjustment was assessed when they were ages 13-14 years and again at ages 20-22 years. At ages 20-22 years, participants' social networking website use and indicators of friendship…

  9. Energy Efficient Four Level Cooperative Opportunistic Communication for Wireless Personal Area Networks (WPAN)

    DEFF Research Database (Denmark)

    Rohokale, Vandana M.; Inamdar, Sandeep; Prasad, Neeli R.

    2013-01-01

    For wireless sensor networks (WSN),energy is a scarce resource. Due to limited battery resources, the energy consumption is the critical issue for the transmission as well as reception of the signals in the wireless communication. WSNs are infrastructure-less shared network demanding more energy ...

  10. Synchronization in an homogeneous, time-varying network with nonuniform time-varying communication delays

    NARCIS (Netherlands)

    Stoorvogel, Antonie Arij; Saberi, Ali; Zhang, Meirong

    2016-01-01

    This paper studies synchronization among identical agents that are coupled through a time-varying network with nonuniform time-varying communication delay. Given an arbitrary upper bound for the delays, a controller design methodology without exact knowledge of the network topology is proposed so

  11. Social Networks, Communication Styles, and Learning Performance in a CSCL Community

    Science.gov (United States)

    Cho, Hichang; Gay, Geri; Davidson, Barry; Ingraffea, Anthony

    2007-01-01

    The aim of this study is to empirically investigate the relationships between communication styles, social networks, and learning performance in a computer-supported collaborative learning (CSCL) community. Using social network analysis (SNA) and longitudinal survey data, we analyzed how 31 distributed learners developed collaborative learning…

  12. Success Factors and Challenges of an Information Communication Technology Network in Rural Schools

    Science.gov (United States)

    Mihai, Maryke A.

    2017-01-01

    In April 2008, an interactive information communication technology (ICT) network was established in Mpumalanga, South Africa. the network involved the implementation of SMART board interactive whiteboards (IWBs) and collaboration between a leading school and several disadvantaged schools. the main purpose of the Mpumalanga IWB project was to reach…

  13. Line-plane broadcasting in a data communications network of a parallel computer

    Science.gov (United States)

    Archer, Charles J.; Berg, Jeremy E.; Blocksome, Michael A.; Smith, Brian E.

    2010-06-08

    Methods, apparatus, and products are disclosed for line-plane broadcasting in a data communications network of a parallel computer, the parallel computer comprising a plurality of compute nodes connected together through the network, the network optimized for point to point data communications and characterized by at least a first dimension, a second dimension, and a third dimension, that include: initiating, by a broadcasting compute node, a broadcast operation, including sending a message to all of the compute nodes along an axis of the first dimension for the network; sending, by each compute node along the axis of the first dimension, the message to all of the compute nodes along an axis of the second dimension for the network; and sending, by each compute node along the axis of the second dimension, the message to all of the compute nodes along an axis of the third dimension for the network.

  14. Reliability modeling of safety-critical network communication in a digitalized nuclear power plant

    International Nuclear Information System (INIS)

    Lee, Sang Hun; Kim, Hee Eun; Son, Kwang Seop; Shin, Sung Min; Lee, Seung Jun; Kang, Hyun Gook

    2015-01-01

    The Engineered Safety Feature-Component Control System (ESF-CCS), which uses a network communication system for the transmission of safety-critical information from group controllers (GCs) to loop controllers (LCs), was recently developed. However, the ESF-CCS has not been applied to nuclear power plants (NPPs) because the network communication failure risk in the ESF-CCS has yet to be fully quantified. Therefore, this study was performed to identify the potential hazardous states for network communication between GCs and LCs and to develop quantification schemes for various network failure causes. To estimate the risk effects of network communication failures in the ESF-CCS, a fault-tree model of an ESF-CCS signal failure in the containment spray actuation signal condition was developed for the case study. Based on a specified range of periodic inspection periods for network modules and the baseline probability of software failure, a sensitivity study was conducted to analyze the risk effect of network failure between GCs and LCs on ESF-CCS signal failure. This study is expected to provide insight into the development of a fault-tree model for network failures in digital I&C systems and the quantification of the risk effects of network failures for safety-critical information transmission in NPPs. - Highlights: • Network reliability modeling framework for digital I&C system in NPP is proposed. • Hazardous states of network protocol between GC and LC in ESF-CCS are identified. • Fault-tree model of ESF-CCS signal failure in ESF actuation condition is developed. • Risk effect of network failure on ESF-CCS signal failure is analyzed.

  15. Cognitive Networking With Regards to NASA's Space Communication and Navigation Program

    Science.gov (United States)

    Ivancic, William D.; Paulsen, Phillip E.; Vaden, Karl R.; Ponchak, Denise S.

    2013-01-01

    This report describes cognitive networking (CN) and its application to NASA's Space Communication and Networking (SCaN) Program. This report clarifies the terminology and framework of CN and provides some examples of cognitive systems. It then provides a methodology for developing and deploying CN techniques and technologies. Finally, the report attempts to answer specific questions regarding how CN could benefit SCaN. It also describes SCaN's current and target networks and proposes places where cognition could be deployed.

  16. Decentralized communication How to send messages to unresponsive clients in a chat network

    OpenAIRE

    Dunér Lundberg, Isak

    2015-01-01

    A communication solution to send messages between clients in a decentralized network even though the receiver may be unreachable at the time of transmission is presented. The solution is build on a decentralized cloud infrastructure and includes cryptically key pairs to perform client authentication. The network is resistant to failures and have redundancy and self healing capabilities built in. To reach this goal we analyse some existing systems and networks which forms the basis for this re...

  17. Wireless Sensor Network Based Smart Grid Communications: Cyber Attacks, Intrusion Detection System and Topology Control

    Directory of Open Access Journals (Sweden)

    Lipi Chhaya

    2017-01-01

    Full Text Available The existing power grid is going through a massive transformation. Smart grid technology is a radical approach for improvisation in prevailing power grid. Integration of electrical and communication infrastructure is inevitable for the deployment of Smart grid network. Smart grid technology is characterized by full duplex communication, automatic metering infrastructure, renewable energy integration, distribution automation and complete monitoring and control of entire power grid. Wireless sensor networks (WSNs are small micro electrical mechanical systems that are deployed to collect and communicate the data from surroundings. WSNs can be used for monitoring and control of smart grid assets. Security of wireless sensor based communication network is a major concern for researchers and developers. The limited processing capabilities of wireless sensor networks make them more vulnerable to cyber-attacks. The countermeasures against cyber-attacks must be less complex with an ability to offer confidentiality, data readiness and integrity. The address oriented design and development approach for usual communication network requires a paradigm shift to design data oriented WSN architecture. WSN security is an inevitable part of smart grid cyber security. This paper is expected to serve as a comprehensive assessment and analysis of communication standards, cyber security issues and solutions for WSN based smart grid infrastructure.

  18. Second language social networks and communication-related acculturative stress: the role of interconnectedness

    Science.gov (United States)

    Doucerain, Marina M.; Varnaamkhaasti, Raheleh S.; Segalowitz, Norman; Ryder, Andrew G.

    2015-01-01

    Although a substantial amount of cross-cultural psychology research has investigated acculturative stress in general, little attention has been devoted specifically to communication-related acculturative stress (CRAS). In line with the view that cross-cultural adaptation and second language (L2) learning are social and interpersonal phenomena, the present study examines the hypothesis that migrants’ L2 social network size and interconnectedness predict CRAS. The main idea underlying this hypothesis is that L2 social networks play an important role in fostering social and cultural aspects of communicative competence. Specifically, higher interconnectedness may reflect greater access to unmodified natural cultural representations and L2 communication practices, thus fostering communicative competence through observational learning. As such, structural aspects of migrants’ L2 social networks may be protective against acculturative stress arising from chronic communication difficulties. Results from a study of first generation migrant students (N = 100) support this idea by showing that both inclusiveness and density of the participants’ L2 network account for unique variance in CRAS but not in general acculturative stress. These results support the idea that research on cross-cultural adaptation would benefit from disentangling the various facets of acculturative stress and that the structure of migrants’ L2 network matters for language related outcomes. Finally, this study contributes to an emerging body of work that attempts to integrate cultural/cross-cultural research on acculturation and research on intercultural communication and second language learning. PMID:26300809

  19. Second language social networks and communication-related acculturative stress: the role of interconnectedness.

    Science.gov (United States)

    Doucerain, Marina M; Varnaamkhaasti, Raheleh S; Segalowitz, Norman; Ryder, Andrew G

    2015-01-01

    Although a substantial amount of cross-cultural psychology research has investigated acculturative stress in general, little attention has been devoted specifically to communication-related acculturative stress (CRAS). In line with the view that cross-cultural adaptation and second language (L2) learning are social and interpersonal phenomena, the present study examines the hypothesis that migrants' L2 social network size and interconnectedness predict CRAS. The main idea underlying this hypothesis is that L2 social networks play an important role in fostering social and cultural aspects of communicative competence. Specifically, higher interconnectedness may reflect greater access to unmodified natural cultural representations and L2 communication practices, thus fostering communicative competence through observational learning. As such, structural aspects of migrants' L2 social networks may be protective against acculturative stress arising from chronic communication difficulties. Results from a study of first generation migrant students (N = 100) support this idea by showing that both inclusiveness and density of the participants' L2 network account for unique variance in CRAS but not in general acculturative stress. These results support the idea that research on cross-cultural adaptation would benefit from disentangling the various facets of acculturative stress and that the structure of migrants' L2 network matters for language related outcomes. Finally, this study contributes to an emerging body of work that attempts to integrate cultural/cross-cultural research on acculturation and research on intercultural communication and second language learning.

  20. Intrusion detection for IP-based multimedia communications over wireless networks

    CERN Document Server

    Tang, Jin

    2013-01-01

    IP-based multimedia communications have become increasingly popular in recent years. With the increasing coverage of the IEEE 802:11™ based wireless networks, IP-based multimedia communications over wireless networks are also drawing extensive attention in both academia and industry. Due to the openness and distributed nature of the protocols involved, such as the session initiation protocol (SIP) and the IEEE 802:11™ standard, it becomes easy for malicious users in the network to achieve their own gain or disrupt the service by deviating from the normal protocol behaviors. This SpringerBrief

  1. Network management and signalling standards for CCSDS advanced orbiting system communication systems

    Science.gov (United States)

    Pietras, John

    The Consultative Committee for Space Data Systems (CCSDS) is an international organization chartered to develop and adopt communications protocols and data processing standards suitable for use in space-related communication and data processing systems. This paper briefly describes the CCSDS network management environment and reviews the current status of CCSDS recommendations for network management functional capability, use of internal standard for network management, and composition of signaling systems in support of the advanced orbiting systems services typified by the international Space Station Freedom Program. A timetable for future work in this area is presented.

  2. Radio Channel Modelling for UAV Communication over Cellular Networks

    DEFF Research Database (Denmark)

    Amorim, Rafhael Medeiros de; Nguyen, Huan Cong; Mogensen, Preben Elgaard

    2017-01-01

    The main goal of this paper is to obtain models for path loss exponents and shadowing for the radio channel between airborne Unmanned Aerial Vehicles (UAVs) and cellular networks. In this pursuit, field measurements were conducted in live LTE networks at the 800 MHz frequency band, using a commer...

  3. Capacity allocation in wireless communication networks - models and analyses

    NARCIS (Netherlands)

    Litjens, Remco

    2003-01-01

    This monograph has concentrated on capacity allocation in cellular and Wireless Local Area Networks, primarily with a network operator’s perspective. In the introduc- tory chapter, a reference model has been proposed for the extensive suite of capacity allocation mechanisms that can be applied at

  4. fraud detection in mobile communications networks using user

    African Journals Online (AJOL)

    DEPT OF AGRICULTURAL ENGINEERING

    Fraud in telecommunications networks can be characterized by fraud conditions, which essen- tially describe how the fraudster gained the illegitimate access to the network. This study concentrated on the detection methodologies based on the calling activity. This is divided into two categories of absolute and differential.

  5. Reliable Uplink Communication through Double Association in Wireless Heterogeneous Networks

    DEFF Research Database (Denmark)

    Kim, Dong Min; Popovski, Petar

    2016-01-01

    We investigate methods for network association that improve the reliability of uplink transmissions in dense wireless heterogeneous networks. The stochastic geometry analysis shows that the double association, in which an uplink transmission is transmitted to a macro Base Station (BS) and small B...

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

    Science.gov (United States)

    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…

  7. Dynamic communications for small satellites using disruption tolerant network concepts

    NARCIS (Netherlands)

    Giuditta, N.; Gill, E.K.A.; Fernández, B.; Isaac, D.

    2009-01-01

    New network technologies are providing interconnectivity in areas previously unheard of. One of these novel technologies, named Disruption Tolerant Networking (DTN), shows promise for the space industry. In order to study its suitability for University projects, a model of a University space mission

  8. Interpreting physical flows in networks as a communication system

    Indian Academy of Sciences (India)

    Indian Academy of Sciences Conference Series (2017) 1:1. In an effort to bridge this gap, some works have dealt with transportation problems on passive networks, namely, traffic flows, setting routines and rules to transport packages across the network and finding numerically the resulting flows and jamming properties.

  9. All-optical virtual private network and ONUs communication in optical OFDM-based PON system.

    Science.gov (United States)

    Zhang, Chongfu; Huang, Jian; Chen, Chen; Qiu, Kun

    2011-11-21

    We propose and demonstrate a novel scheme, which enables all-optical virtual private network (VPN) and all-optical optical network units (ONUs) inter-communications in optical orthogonal frequency-division multiplexing-based passive optical network (OFDM-PON) system using the subcarrier bands allocation for the first time (to our knowledge). We consider the intra-VPN and inter-VPN communications which correspond to two different cases: VPN communication among ONUs in one group and in different groups. The proposed scheme can provide the enhanced security and a more flexible configuration for VPN users compared to the VPN in WDM-PON or TDM-PON systems. The all-optical VPN and inter-ONU communications at 10-Gbit/s with 16 quadrature amplitude modulation (16 QAM) for the proposed optical OFDM-PON system are demonstrated. These results verify that the proposed scheme is feasible. © 2011 Optical Society of America

  10. Evaluation of ETCS performance with LTE as alternative railway communication network using OPNET

    DEFF Research Database (Denmark)

    Sniady, Aleksander; Soler, José

    2013-01-01

    GSM-Railways (GSM-R) is a communication mobile network designed to fulfill specific communication needs of railways. GSM-R is being widely deployed across Europe and other countries around the world for providing railway voice and train control services (ETCS). Despite that, GSM-R already shows...... various shortcomings in terms of capacity and support for additional data services. This triggers the issue whether railways could greatly benefit from an alternative communication technology. One of the possible alternatives is LTE. In our work we analyze delivery of railway services over an LTE network....... This work is done using OPNET as simulator for modeling real life railway scenarios and communication infrastructure. These scenarios take advantage of OPNET features allowing modeling an end-to-end LTE network, as well as trains movement over an exemplary real life railway line....

  11. Utilizing Social Network Services for Enhanced Communication with Elderly Living at Home

    DEFF Research Database (Denmark)

    Wagner, Stefan

    2009-01-01

    This paper discusses whether social network services, like Facebook and Twitter, may be used by elderly living in their own homes to enhance communication with their relatives and friends. It introduces a prototype solution based on the iRobot Roomba 560, iRobot, USA, robot vacuum cleaner, which ...... has been enhanced with Facebook and Twitter communication capabilities. The paper points out a number of other relevant applications where the use of social network services may provide better communication for ambient assisted living solutions and intelligent environments.......This paper discusses whether social network services, like Facebook and Twitter, may be used by elderly living in their own homes to enhance communication with their relatives and friends. It introduces a prototype solution based on the iRobot Roomba 560, iRobot, USA, robot vacuum cleaner, which...

  12. Limits on the Capacity of In-Band Full Duplex Communication in Uplink Cellular Networks

    KAUST Repository

    Randrianantenaina, Itsikiantsoa

    2016-02-26

    Simultaneous co-channel transmission and reception, denoted as in-band full duplex (FD) communication, has been promoted as an attractive solution to improve the spectral efficiency of cellular networks. However, in addition to the selfinterference problem, cross-mode interference (i.e., between uplink and downlink) imposes a major obstacle for the deployment of FD communication in cellular networks. More specifically, the downlink to uplink interference represents the performance bottleneck for FD operation due to the uplink limited transmission power and venerable operation when compared to the downlink counterpart. While the positive impact of FD communication to the downlink performance has been proved in the literature, its effect on the uplink transmission has been neglected. This paper focuses on the effect of downlink interference on the uplink transmission in FD cellular networks in order to see whether FD communication is beneficial for the uplink transmission or not, and if yes for which type of network. To quantify the expected performance gains, we derive a closed form expression of the maximum achievable uplink capacity in FD cellular networks. In contrast to the downlink capacity which always improves with FD communication, our results show that the uplink performance may improves or degrades depending on the associated network parameters. Particularly, we show that the intensity of base stations (BSs) has a more prominent effect on the uplink performance than their transmission power.

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

    Science.gov (United States)

    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.

  14. Devices and Control Strategies for AD HOC Optical Communications Networks

    National Research Council Canada - National Science Library

    Baillieul, John; Bifano, Thomas G

    2006-01-01

    ... (both hardware and operational concepts) that we plan to develop in initiating an ambitious program of research to develop a radical new technology for high-bandwidth, stealthy communication over free-space optical links...

  15. Radar network communication through sensing of frequency hopping

    Science.gov (United States)

    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.

  16. Just between us: Exclusive communications in online social networks.

    Science.gov (United States)

    Carpenter, Jordan; Green, Melanie; Laflam, Jeff

    2018-01-24

    Social media websites such as Facebook are used for relationship development and maintenance often through self-disclosure and sharing of personal information. However, not all forms of social media communication may be equally suitable for this task. This paper explores users' norms about the appropriateness of using private vs. public Facebook messages to communicate different kinds of personal information, and the effectiveness of these types of communication in building relationships. Study 1, a survey, revealed that users endorse conflicting expectations about preferences for receiving information publicly or privately. Study 2, a field experiment testing the effects of private versus public Facebook communications on actual relationship development using participants' own Facebook pages, suggested that private messages lead to greater closeness.

  17. Exponential networked synchronization of master-slave chaotic systems with time-varying communication topologies

    International Nuclear Information System (INIS)

    Yang Dong-Sheng; Liu Zhen-Wei; Liu Zhao-Bing; Zhao Yan

    2012-01-01

    The networked synchronization problem of a class of master-slave chaotic systems with time-varying communication topologies is investigated in this paper. Based on algebraic graph theory and matrix theory, a simple linear state feedback controller is designed to synchronize the master chaotic system and the slave chaotic systems with a time-varying communication topology connection. The exponential stability of the closed-loop networked synchronization error system is guaranteed by applying Lyapunov stability theory. The derived novel criteria are in the form of linear matrix inequalities (LMIs), which are easy to examine and tremendously reduce the computation burden from the feedback matrices. This paper provides an alternative networked secure communication scheme which can be extended conveniently. An illustrative example is given to demonstrate the effectiveness of the proposed networked synchronization method. (general)

  18. Voice Communications over 802.11 Ad Hoc Networks: Modeling, Optimization and Call Admission Control

    Science.gov (United States)

    Xu, Changchun; Xu, Yanyi; Liu, Gan; Liu, Kezhong

    Supporting quality-of-service (QoS) of multimedia communications over IEEE 802.11 based ad hoc networks is a challenging task. This paper develops a simple 3-D Markov chain model for queuing analysis of IEEE 802.11 MAC layer. The model is applied for performance analysis of voice communications over IEEE 802.11 single-hop ad hoc networks. By using the model, we finish the performance optimization of IEEE MAC layer and obtain the maximum number of voice calls in IEEE 802.11 ad hoc networks as well as the statistical performance bounds. Furthermore, we design a fully distributed call admission control (CAC) algorithm which can provide strict statistical QoS guarantee for voice communications over IEEE 802.11 ad hoc networks. Extensive simulations indicate the accuracy of the analytical model and the CAC scheme.

  19. Communication and cybercoping: coping with chronic illness through communicative action in online support networks.

    Science.gov (United States)

    Kim, Jeong-Nam; Lee, Seungyoon

    2014-01-01

    Computer-mediated communication, specifically blogs, has expanded the range of the communicative action of patients with chronic disease from information seeking to information forwarding. The authors examine the effects of these 2 types of communicative action on perceived affective and physical coping outcomes. Using a survey dataset of 254 chronic disease patients, the authors tested 2 models using structural equation modeling: first, the effects of communicative action about chronic illness on coping outcomes; and second, the mediating role of emotion-focused and problem-focused coping processes. Findings indicate overall positive effects of communicative action on coping processes and outcomes, yet with different magnitudes of effects depending on the dimensions of communication behavior, the coping process, and outcome. Implications for patients and health care providers are discussed.

  20. Full Duplex Communications in 5G Small Cells

    DEFF Research Database (Denmark)

    Mahmood, Nurul Huda; Gatnau, Marta; Berardinelli, Gilberto

    2017-01-01

    Full duplex communication promises system performance improvement over conventional half duplex communication by allowing simultaneous transmission and reception. However, such concurrent communication results in strong self interference and an increase in the overall network interference, and ca...

  1. PROBLEM OF INTERNET COMMUNICATION OF UPPER SECONDARY SCHOOL PUPILS IN ELECTRONIC SOCIAL NETWORKS

    Directory of Open Access Journals (Sweden)

    Olga E. Konevshchynska

    2017-09-01

    Full Text Available The article deals with the problem of Internet communication of upper secondary school pupils during interpersonal communication in electronic social networks. The actuality is proved, the system analysis of the psychological and pedagogical, educational-methodical literature of the researched problem is carried out. External written Internet speaking is considered as an important factor in the communication culture of the individual. It has been determined that high level of Internet communication of both students and teachers in the process of interpersonal communication in electronic social networks are important aspects of raising the level of media culture, media information competence of the individual. Also, these ones are necessary requirements of the information society to fulfill project-oriented, educational-cognitive and effective innovative activity in educational practice.

  2. 78 FR 55096 - Certain Point-to-Point Network Communication Devices and Products Containing Same; Institution of...

    Science.gov (United States)

    2013-09-09

    ... sale within the United States after importation of certain point-to- point network communication... sale within the United States after importation of certain point-to- point network communication... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-892] Certain Point-to-Point Network...

  3. Implementing Virtual Private Networking for Enabling Lower Cost, More Secure Wide Area Communications at Sandia National Laboratories; TOPICAL

    International Nuclear Information System (INIS)

    MILLER, MARC M.; YONEK JR., GEORGE A.

    2001-01-01

    Virtual Private Networking is a new communications technology that promises lower cost, more secure wide area communications by leveraging public networks such as the Internet. Sandia National Laboratories has embraced the technology for interconnecting remote sites to Sandia's corporate network, and for enabling remote access users for both dial-up and broadband access

  4. Interfacial Stabilization of Fiber-Laden Foams with Carboxymethylated Lignin toward Strong Nonwoven Networks.

    Science.gov (United States)

    Li, Shuai; Xiang, Wenchao; Järvinen, Marjo; Lappalainen, Timo; Salminen, Kristian; Rojas, Orlando J

    2016-08-03

    Wet foams were produced via agitation and compressed air bubbling of aqueous solutions of carboxymethylated lignin (CML). Bubble size and distribution were assessed in situ via optical microscopy. Foamability, bubble collapse rate, and foam stability (half-life time) were analyzed as a function of CML concentration, temperature, pH, and air content. Dynamic changes of the CML liquid foam were monitored by light transmission and backscattering. Cellulosic fibers of different aspect ratios (long pine fibers and short birch fibers) were suspended under agitation by the liquid foams (0.6% CML in the aqueous phase) with an air (bubble) content as high as 75% in volume. Remarkably, the half-life time of fiber-laden CML foams was 10-fold higher than that of the corresponding fiber-free liquid foam. Such lignin-based foams were demonstrated, after dewatering, as a precursor for the synthesis of nonwoven, layered structures. The resulting fiber networks (paper), obtained here for the first time with lignin-based foams, were characterized for pore size distribution, lignin retention, morphology, and physical-mechanical properties (network formation quality, density, air permeability, surface roughness, and tensile and internal bond strengths). The results were compared against structures obtained from foams stabilized with an anionic surfactant (SDS) as well as those from foam-free, water-based web-laying. Remarkably, compared to SDS, the foam-formed materials produced with CML displayed better bonding and tensile strengths. Overall, CML-based foams were found to be suitable carriers of cellulosic fibers and have opened the possibility for integrating fully biobased systems in foam-forming. This is an emerging option to increase the effective solids content in the system without compromising the quality of formed nonwoven materials while achieving reductions in water and energy consumption.

  5. 75 FR 26180 - Effects on Broadband Communications Networks of Damage To or Failure of Network Equipment or...

    Science.gov (United States)

    2010-05-11

    ... electronically using the Internet by accessing the ECFS: http://fjallfoss.fcc.gov/ecfs2/ or the Federal e... internet service providers). As Americans increasingly rely on broadband communications networks for voice... operational awareness do broadband service providers have on these dependencies? For example is the state of...

  6. SDN-Enabled Communication Network Framework for Energy Internet

    Directory of Open Access Journals (Sweden)

    Zhaoming Lu

    2017-01-01

    Full Text Available To support distributed energy generators and improve energy utilization, energy Internet has attracted global research focus. In China, energy Internet has been proposed as an important issue of government and institutes. However, managing a large amount of distributed generators requires smart, low-latency, reliable, and safe networking infrastructure, which cannot be supported by traditional networks in power grids. In order to design and construct smart and flexible energy Internet, we proposed a software defined network framework with both microgrid cluster level and global grid level designed by a hierarchical manner, which will bring flexibility, efficiency, and reliability for power grid networks. Finally, we evaluate and verify the performance of this framework in terms of latency, reliability, and security by both theoretical analysis and real-world experiments.

  7. Wideband Autonomous Cognitive Radios for Networked Satellites Communications, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Wideband Autonomous Cognitive Radios (WACRs) are advanced radios that have the ability to sense state of the RF spectrum and the network and self-optimize its...

  8. Performance of Group Communication Over Ad-Hoc Networks

    National Research Council Canada - National Science Library

    Mosko, Marc; Garcia-Luna-Aceves, J. J

    2002-01-01

    .... To obtain analytical results while preserving hidden-terminal and node clustering characteristics of ah-hoc networks, we introduce a novel differential-equation fluid model for information flow...

  9. The hippocampus: hub of brain network communication for memory.

    NARCIS (Netherlands)

    Battaglia, F.P.; Benchenane, K.; Sirota, A.; Pennartz, C.M.A.; Wiener, S.I.

    2011-01-01

    A complex brain network, centered on the hippocampus, supports episodic memories throughout their lifetimes. Classically, upon memory encoding during active behavior, hippocampal activity is dominated by theta oscillations (6-10Hz). During inactivity, hippocampal neurons burst synchronously,

  10. The performance evaluation of a new neural network based traffic management scheme for a satellite communication network

    Science.gov (United States)

    Ansari, Nirwan; Liu, Dequan

    1991-01-01

    A neural-network-based traffic management scheme for a satellite communication network is described. The scheme consists of two levels of management. The front end of the scheme is a derivation of Kohonen's self-organization model to configure maps for the satellite communication network dynamically. The model consists of three stages. The first stage is the pattern recognition task, in which an exemplar map that best meets the current network requirements is selected. The second stage is the analysis of the discrepancy between the chosen exemplar map and the state of the network, and the adaptive modification of the chosen exemplar map to conform closely to the network requirement (input data pattern) by means of Kohonen's self-organization. On the basis of certain performance criteria, whether a new map is generated to replace the original chosen map is decided in the third stage. A state-dependent routing algorithm, which arranges the incoming call to some proper path, is used to make the network more efficient and to lower the call block rate. Simulation results demonstrate that the scheme, which combines self-organization and the state-dependent routing mechanism, provides better performance in terms of call block rate than schemes that only have either the self-organization mechanism or the routing mechanism.

  11. Nanoscale molecular communication networks: a game-theoretic perspective

    Science.gov (United States)

    Jiang, Chunxiao; Chen, Yan; Ray Liu, K. J.

    2015-12-01

    Currently, communication between nanomachines is an important topic for the development of novel devices. To implement a nanocommunication system, diffusion-based molecular communication is considered as a promising bio-inspired approach. Various technical issues about molecular communications, including channel capacity, noise and interference, and modulation and coding, have been studied in the literature, while the resource allocation problem among multiple nanomachines has not been well investigated, which is a very important issue since all the nanomachines share the same propagation medium. Considering the limited computation capability of nanomachines and the expensive information exchange cost among them, in this paper, we propose a game-theoretic framework for distributed resource allocation in nanoscale molecular communication systems. We first analyze the inter-symbol and inter-user interference, as well as bit error rate performance, in the molecular communication system. Based on the interference analysis, we formulate the resource allocation problem as a non-cooperative molecule emission control game, where the Nash equilibrium is found and proved to be unique. In order to improve the system efficiency while guaranteeing fairness, we further model the resource allocation problem using a cooperative game based on the Nash bargaining solution, which is proved to be proportionally fair. Simulation results show that the Nash bargaining solution can effectively ensure fairness among multiple nanomachines while achieving comparable social welfare performance with the centralized scheme.

  12. Multiscale analysis of spreading in a large communication network

    International Nuclear Information System (INIS)

    Kivelä, Mikko; Pan, Raj Kumar; Kaski, Kimmo; Kertész, János; Saramäki, Jari; Karsai, Márton

    2012-01-01

    In temporal networks, both the topology of the underlying network and the timings of interaction events can be crucial in determining how a dynamic process mediated by the network unfolds. We have explored the limiting case of the speed of spreading in the SI model, set up such that an event between an infectious and a susceptible individual always transmits the infection. The speed of this process sets an upper bound for the speed of any dynamic process that is mediated through the interaction events of the network. With the help of temporal networks derived from large-scale time-stamped data on mobile phone calls, we extend earlier results that indicate the slowing-down effects of burstiness and temporal inhomogeneities. In such networks, links are not permanently active, but dynamic processes are mediated by recurrent events taking place on the links at specific points in time. We perform a multiscale analysis and pinpoint the importance of the timings of event sequences on individual links, their correlations with neighboring sequences, and the temporal pathways taken by the network-scale spreading process. This is achieved by studying empirically and analytically different characteristic relay times of links, relevant to the respective scales, and a set of temporal reference models that allow for removing selected time-domain correlations one by one. Our analysis shows that for the spreading velocity, time-domain inhomogeneities are as important as the network topology, which indicates the need to take time-domain information into account when studying spreading dynamics. In particular, results for the different characteristic relay times underline the importance of the burstiness of individual links

  13. Attacks and Countermeasures in Communications and Power Networks

    Science.gov (United States)

    2014-01-01

    through monitored nodes, the network owner can alert the possibility of an attack. Other applications include the detec- tion of wormhole attack [64] in...which a set of colluding nodes divert a valid network flow through a “ wormhole tunnel.” Understanding the problem of flow detection is also valuable for...Sterne, R. Gopaul, M. Heyman, B. Rivera, P. Budulas, B. Luu, T. Johnson, N. Ivanic, and G. Lawler, “In-Band Wormholes and Countermea- sures in OLSR

  14. Nano-topography Enhances Communication in Neural Cells Networks.

    Science.gov (United States)

    Onesto, V; Cancedda, L; Coluccio, M L; Nanni, M; Pesce, M; Malara, N; Cesarelli, M; Di Fabrizio, E; Amato, F; Gentile, F

    2017-08-29

    Neural cells are the smallest building blocks of the central and peripheral nervous systems. Information in neural networks and cell-substrate interactions have been heretofore studied separately. Understanding whether surface nano-topography can direct nerve cells assembly into computational efficient networks may provide new tools and criteria for tissue engineering and regenerative medicine. In this work, we used information theory approaches and functional multi calcium imaging (fMCI) techniques to examine how information flows in neural networks cultured on surfaces with controlled topography. We found that substrate roughness S a affects networks topology. In the low nano-meter range, S a  = 0-30 nm, information increases with S a . Moreover, we found that energy density of a network of cells correlates to the topology of that network. This reinforces the view that information, energy and surface nano-topography are tightly inter-connected and should not be neglected when studying cell-cell interaction in neural tissue repair and regeneration.

  15. Nano-topography Enhances Communication in Neural Cells Networks

    KAUST Repository

    Onesto, V.

    2017-08-23

    Neural cells are the smallest building blocks of the central and peripheral nervous systems. Information in neural networks and cell-substrate interactions have been heretofore studied separately. Understanding whether surface nano-topography can direct nerve cells assembly into computational efficient networks may provide new tools and criteria for tissue engineering and regenerative medicine. In this work, we used information theory approaches and functional multi calcium imaging (fMCI) techniques to examine how information flows in neural networks cultured on surfaces with controlled topography. We found that substrate roughness Sa affects networks topology. In the low nano-meter range, S-a = 0-30 nm, information increases with Sa. Moreover, we found that energy density of a network of cells correlates to the topology of that network. This reinforces the view that information, energy and surface nano-topography are tightly inter-connected and should not be neglected when studying cell-cell interaction in neural tissue repair and regeneration.

  16. Short Communication: HIV-1 Transmission Networks Across South Korea.

    Science.gov (United States)

    Ahn, Mi Young; Wertheim, Joel O; Kim, Woo Joo; Kim, Shin-Woo; Lee, Jin Soo; Ann, Hea Won; Jeon, Yongduk; Ahn, Jin Young; Song, Je Eun; Oh, Dong Hyun; Kim, Yong Chan; Kim, Eun Jin; Jung, In Young; Kim, Moo Hyun; Jeong, Wooyoung; Jeong, Su Jin; Ku, Nam Su; Kim, June Myung; Smith, Davey M; Choi, Jun Yong

    2017-08-01

    Molecular epidemiology can help clarify the properties and dynamics of HIV-1 transmission networks in both global and regional scales. We studied 143 HIV-1-infected individuals recruited from four medical centers of three cities in South Korea between April 2013 and May 2014. HIV-1 env V3 sequence data were generated (337-793 bp) and analyzed using a pairwise distance-based clustering approach to infer putative transmission networks. Participants whose viruses were ≤2.0% divergent according to Tamura-Nei 93 genetic distance were defined as clustering. We collected demographic, risk, and clinical data and analyzed these data in relation to clustering. Among 143 participants, we identified nine putative transmission clusters of different sizes (range 2-4 participants). The reported risk factor of participants were concordant in only one network involving two participants, that is, both individuals reported homosexual sex as their risk factor. The participants in the other eight networks did not report concordant risk factors, although they were phylogenetically linked. About half of the participants refused to report their risk factor. Overall, molecular epidemiology provides more information to understand local transmission networks and the risks associated with these networks.

  17. Synchronization of Switched Neural Networks With Communication Delays via the Event-Triggered Control.

    Science.gov (United States)

    Wen, Shiping; Zeng, Zhigang; Chen, Michael Z Q; Huang, Tingwen

    2017-10-01

    This paper addresses the issue of synchronization of switched delayed neural networks with communication delays via event-triggered control. For synchronizing coupled switched neural networks, we propose a novel event-triggered control law which could greatly reduce the number of control updates for synchronization tasks of coupled switched neural networks involving embedded microprocessors with limited on-board resources. The control signals are driven by properly defined events, which depend on the measurement errors and current-sampled states. By using a delay system method, a novel model of synchronization error system with delays is proposed with the communication delays and event-triggered control in the unified framework for coupled switched neural networks. The criteria are derived for the event-triggered synchronization analysis and control synthesis of switched neural networks via the Lyapunov-Krasovskii functional method and free weighting matrix approach. A numerical example is elaborated on to illustrate the effectiveness of the derived results.

  18. Throughput, Energy and Overhead of Multicast Device-to-Device Communications with Network Coded Cooperation

    DEFF Research Database (Denmark)

    Hernandez, Nestor; Heide, Janus; Roetter, Daniel Enrique Lucani

    2017-01-01

    Cooperation strategies in mobile networks typically rely in short range technologies, like LTE-A Device to Device (D2D) communications, for data exchange between devices forming mobile clouds. These communications provide a better device experience since the clouds offload the network. Nevertheless......, this assumes that the throughput gains and energy savings in multicasting are much larger between devices than the base station to the receivers. However, current mobile networks suffer from many different issues varying the performance in data rates, which calls into question these assumptions. Therefore......, a first objective of this work is to assess the operating regions where employing cooperation results in higher throughput and/or energy savings. We consider multicast scenarios with network coded mechanisms employing Random Linear Network Coding (RLNC). However, although RLNC is good for low amount...

  19. Offline Social Relationships and Online Cancer Communication: Effects of Social and Family Support on Online Social Network Building.

    Science.gov (United States)

    Namkoong, Kang; Shah, Dhavan V; Gustafson, David H

    2017-11-01

    This study investigates how social support and family relationship perceptions influence breast cancer patients' online communication networks in a computer-mediated social support (CMSS) group. To examine social interactions in the CMSS group, we identified two types of online social networks: open and targeted communication networks. The open communication network reflects group communication behaviors (i.e., one-to-many or "broadcast" communication) in which the intended audience is not specified; in contrast, the targeted communication network reflects interpersonal discourses (i.e., one-to-one or directed communication) in which the audience for the message is specified. The communication networks were constructed by tracking CMSS group usage data of 237 breast cancer patients who participated in one of two National Cancer Institute-funded randomized clinical trials. Eligible subjects were within 2 months of a diagnosis of primary breast cancer or recurrence at the time of recruitment. Findings reveal that breast cancer patients who perceived less availability of offline social support had a larger social network size in the open communication network. In contrast, those who perceived less family cohesion had a larger targeted communication network in the CMSS group, meaning they were inclined to use the CMSS group for developing interpersonal relationships.

  20. Use of communication architecture test bed to evaluate data network performance

    International Nuclear Information System (INIS)

    Clapp, N.E. Jr.; Swail, B.K.; Naser, J.A.

    1994-01-01

    Local area networks (LANs) are becoming more prevalent in nuclear power plants. Traditionally, LANs were only used as information highways, providing office automation services. LANs are now being used as data highways for applications in plant data acquisition and control systems. A communication architecture test bed, which contains network simulators, is needed to allow network performance studies and to resolve design issues prior to equipment purchase. Two levels of granularity of simulation are needed to provide the dynamic information about network performance. A coarse-grain simulator is used to estimate the dynamic performance of the network due to major resources such as workstations, gateways, and data acquisition systems. A fine-grain simulator allows a greater level of detail about the underlying network protocol and resources to be simulated. The combination of coarse-grain and fine-grain simulation packages provides the network designer with the required tools to thoroughly understand the behavior of the modeled network. This paper describes the development of a communication architecture test bed using commercial network simulation packages. Network simulators allow the resolution of major design issues in software without the expense of purchasing costly hardware components