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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. 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

  3. 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...

  4. Data communications and computer communications network

    International Nuclear Information System (INIS)

    Kim, Jang Gwon; Gu, Chang Hoe

    2005-03-01

    This textbook is composed of twelve chapters, which are communication network introduction, foundation of data communication, data link control, circuit switching system, packet switching system, multiple access communication system, protocol and architecture, LAN, MAN communication network, integrated service digital network, internet and Asymmetric digital subscriber Line and Wireless Local Loop. Each chapter has the introduction of the technique, structure, function and practice problems. It also has the appendix on electricity and communication standards organization, characteristic table and glossary.

  5. Communication Network Analysis Methods.

    Science.gov (United States)

    Farace, Richard V.; Mabee, Timothy

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

  6. 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.

  7. 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 ...

  8. Connectivist Communication Networks

    Science.gov (United States)

    Waßmann, Ingolf; Nicolay, Robin; Martens, Alke

    2016-01-01

    Facing the challenges of the digital age concerning lifelong learning, this contribution presents an approach to dynamically establish Connectivist communication networks. According the statement "the pipe is more important than the content within the pipe" by Georg Siemens, learning in digital age includes the connection of people to…

  9. 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

  10. Communicability across evolving networks.

    Science.gov (United States)

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

    2011-04-01

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

  11. 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

  12. 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?

  13. STRONG POINTS AND INTERNAL AND EXTERNAL VULNERABILITIES OF THE MILITARY COMMUNICATIONS AND INFORMATICS SYSTEMS AND NETWORKS DEVELOPED IN THE ROMANIAN ARMED FORCES UNDER THE CIRCUMSTANCES OF THE CURRENT SECURITY CHALLENGES

    Directory of Open Access Journals (Sweden)

    Constantin MINCU

    2015-12-01

    Full Text Available The author briefly presents a series of recent aspects in the current geopolitical context regarding some strong points as well as internal and external vulnerabilities of the military communication and informatics systems and networks developed in the Romanian Armed Forces since 1997. In the second section we referred to the evolutions in austerity and hostility conditions of the main operational and technical sequels of Romanian Armed Forces Transmissions System - STAR (RTP/RMNC. Furthermore, we presented some strong points of the achieved systems and principles taken into account along the modernization and transformation effort (regarding the NATO criteria and requirements, as well as their internal and external vulnerabilities identified following a thorough analysis.

  14. 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...

  15. 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

  16. 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,...

  17. 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.

  18. 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.

  19. 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...

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. Multiple-Ring Digital Communication Network

    Science.gov (United States)

    Kirkham, Harold

    1992-01-01

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

  5. 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.

  6. 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

  7. 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.

  8. Communications for unattended sensor networks

    Science.gov (United States)

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

    2004-07-01

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

  9. Applied data communications and networks

    CERN Document Server

    Buchanan, W

    1996-01-01

    The usage of data communications and computer networks are ever in­ creasing. It is one of the few technological areas which brings benefits to most of the countries and the peoples of the world. Without it many industries could not exist. It is the objective of this book to discuss data communications in a readable form that students and professionals all over the world can understand. As much as possible the text uses dia­ grams to illustrate key points. Most currently available data communications books take their view­ point from either a computer scientists top-down approach or from an electronic engineers bottom-up approach. This book takes a practical ap­ proach and supports it with a theoretical background to create a textbook which can be used by electronic engineers, computer engineers, computer scientists and industry professionals. It discusses most of the current and future key data communications technologies, including: • Data Communications Standards and Models; • Local Area Networks (...

  10. 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.

  11. VSAT communications networks - An overview

    Science.gov (United States)

    Chakraborty, D.

    1988-05-01

    The very-small-aperture-terminal (VSAT) fixed satellite communication network is a star network in which many dispersed micro terminals attempt to send data in a packet form through a random access/time-division multiple-access (RA/TDMA) satellite channel with transmission delay. The basic concept of the VSAT and its service potential are discussed. Two classes of traffic are addressed, namely, business-oriented low-rate-data traffic and bulk data traffic of corporate networks. Satellite access, throughput, and delay are considered. The size of the network population that can be served in an RA/TDMA environment is calculated. User protocols are examined. A typical VSAT business scenario is described.

  12. Information communication on complex networks

    International Nuclear Information System (INIS)

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

    2013-01-01

    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.

  13. Communication through resonance in spiking neuronal networks.

    Science.gov (United States)

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

    2014-08-01

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

  14. 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.

  15. Network Approach in Political Communication Studies

    Directory of Open Access Journals (Sweden)

    Нина Васильевна Опанасенко

    2013-12-01

    Full Text Available The article is devoted to issues of network approach application in political communication studies. The author considers communication in online and offline areas and gives the definition of rhizome, its characteristics, identifies links between rhizome and network approach. The author also analyses conditions and possibilities of the network approach in modern political communication. Both positive and negative features of the network approach are emphasized.

  16. 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

  17. Advances and Challenges in Convergent Communication Networks

    DEFF Research Database (Denmark)

    Toral-Cruz, Homero; Mihovska, Albena

    2017-01-01

    Welcome to this special issue of Wireless Personal Communications on Advances and Challenges in Convergent Communication Networks. The main purpose of this special issue is to present new progresses and challenges in convergent networks. Communication networks play an important role in our daily...... life because they allow communicating and sharing contents between heterogeneous nodes around the globe. The emergence of multiple network architectures and emerging technologies have resulted in new applications and services over a heterogeneous network. This heterogeneous network has undergone...... significant challenges in recent years, such as the evolution to a converged network with the capability to support multiple services, while maintaining a satisfactory level of QoE/QoS, security, efficiency and trust. The special issue on Advances and Challenges in Convergent Communication Networks...

  18. 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...

  19. Chaotic secure communication based on strong tracking filtering

    International Nuclear Information System (INIS)

    Li Xiongjie; Xu Zhengguo; Zhou Donghua

    2008-01-01

    A scheme for implementing secure communication based on chaotic maps and strong tracking filter (STF) is presented, and a modified STF algorithm with message estimation is developed for the special requirement of chaotic secure communication. At the emitter, the message symbol is modulated by chaotic mapping and is output through a nonlinear function. At the receiver, the driving signal is received and the message symbol is recovered dynamically by the STF with estimation of message symbol. Simulation results of Holmes map demonstrate that when message symbols are binary codes, STF can effectively recover the codes of the message from the noisy chaotic signals. Compared with the extended Kalman filter (EKF), STF has a lower bit error rate

  20. The network communication of BEPC control system

    International Nuclear Information System (INIS)

    Xu Jingwei

    1997-01-01

    The author introduces the application of network communication of BEPC control system. The authors use non-transparent communication to transfer the data and command information from node VAX750 to VAX4500

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. Next generation satellite communications networks

    Science.gov (United States)

    Garland, P. J.; Osborne, F. J.; Streibl, I.

    The paper introduces two potential uses for new space hardware to permit enhanced levels of signal handling and switching in satellite communication service for Canada. One application involves increased private-sector services in the Ku band; the second supports new personal/mobile services by employing higher levels of handling and switching in the Ka band. First-generation satellite regeneration and switching experiments involving the NASA/ACTS spacecraft are described, where the Ka band and switching satellite network problems are emphasized. Second-generation satellite development is outlined based on demand trends for more packet-based switching, low-cost earth stations, and closed user groups. A demonstration mission for new Ka- and Ku-band technologies is proposed, including the payload configuration. The half ANIK E payload is shown to meet the demonstration objectives, and projected to maintain a fully operational payload for at least 10 years.

  6. 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.

  7. 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)

  8. Communication networks of men facing a diagnosis of prostate cancer.

    Science.gov (United States)

    Brown, Dot; Oetzel, John; Henderson, Alison

    2016-11-01

    This study seeks to identify the factors that shape the communication networks of men who face a potential diagnosis of prostate cancer, and how these factors relate to their disclosure about their changing health status. Men facing a potential diagnosis of prostate cancer are in a challenging situation; the support benefits of disclosing their changing health status to others in their communication networks is set against a backdrop of the potential stigma and uncertainty of the diagnosis. All men on a prostate biopsy waiting list were eligible for inclusion in an exploratory and interpretive study. Semi-structured interviews with 40 men explored their network structures and disclosure of health information. Thematic analysis highlighted the factors which contributed to their network structures and their disclosure about their health status. Four network factors shaped men's perspectives about disclosing their health status: (1) tie strength, comprising both strong and weak ties; (2) knowledgeable others, with a focus on medical professionals in the family; (3) homophily, which included other individuals with a similar medical condition; and (4) geographical proximity, with a preference for face-to-face communication. Communication networks influence men's disclosure of their health status and in particular weak ties with medical knowledge have an important role. Men who use the potential for support in their networks may experience improved psychosocial outcomes. Using these four network factors-tie strength, knowledgeable others, homophily or geographical proximity-to forecast men's willingness to disclose helps identify men who lack potential support and so are at risk of poor psychosocial health. Those with few strong ties or knowledgeable others in their networks may be in the at-risk cohort. The support provided in communication networks complements formal medical care from nurses and other health professionals, and encouraging patients to use their

  9. 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....

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

    African Journals Online (AJOL)

    Agricultural informational flow in informal communication networks of farmers in Ghana. ... should identify such farmers who can serve as intermediaries between actors to help disseminate information in rural communities. Keywords: key communicators, farmers, rural communities, social networks, extension agents ...

  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. 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)

  13. 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

  14. 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

  15. Network Restoration for Next-Generation Communication and Computing Networks

    Directory of Open Access Journals (Sweden)

    B. S. Awoyemi

    2018-01-01

    Full Text Available Network failures are undesirable but inevitable occurrences for most modern communication and computing networks. A good network design must be robust enough to handle sudden failures, maintain traffic flow, and restore failed parts of the network within a permissible time frame, at the lowest cost achievable and with as little extra complexity in the network as possible. Emerging next-generation (xG communication and computing networks such as fifth-generation networks, software-defined networks, and internet-of-things networks have promises of fast speeds, impressive data rates, and remarkable reliability. To achieve these promises, these complex and dynamic xG networks must be built with low failure possibilities, high network restoration capacity, and quick failure recovery capabilities. Hence, improved network restoration models have to be developed and incorporated in their design. In this paper, a comprehensive study on network restoration mechanisms that are being developed for addressing network failures in current and emerging xG networks is carried out. Open-ended problems are identified, while invaluable ideas for better adaptation of network restoration to evolving xG communication and computing paradigms are discussed.

  16. Applications of Coding in Network Communications

    Science.gov (United States)

    Chang, Christopher SungWook

    2012-01-01

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

  17. 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 ...

  18. 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...

  19. Efficient Networks Communication Routing Using Swarm Intelligence

    OpenAIRE

    Koushal Kumar

    2012-01-01

    As demonstrated by natural biological swarm’s collective intelligence has an abundance of desirable properties for problem-solving like in network routing. The focus of this paper is in the applications of swarm based intelligence in information routing for communication networks. As we know networks are growing and adopting new platforms as new technologies comes. Also according to new demands and requirements networks topologies and its complexity is increasing with time. Thus it is becomin...

  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. Design Considerations for Multi-Channel Picture Communication Networks

    OpenAIRE

    Scheibe, Paul O.

    1983-01-01

    Design of networks intended for communication of digitally-encoded pictures involves considerations different from those used in the design of text or voice communication networks. This paper provides an overview of the elements useful in the design of picture communication networks by relation and contrast with other communication networks. Particular emphasis is given to picture communication systems useful in medical applications.

  2. Optimization and Control of Communication Networks

    OpenAIRE

    Chiang, Mung; Low, Steven

    2005-01-01

    Recently, there has been a surge in research activities that utilize the power of recent developments in nonlinear optimization to tackle a wide scope of work in the analysis and design of communication systems, touching every layer of the layered network architecture, and resulting in both intellectual and practical impacts significantly beyond the earlier frameworks. These research activities are driven by both new demands in the areas of communications and networking, and n...

  3. Jana: Confidential Communications on Social Networks

    Science.gov (United States)

    2017-08-09

    consuming phone resources and privacy leakage ?” We address this challenge via an extensive user study. Next, we ask “How can we detect background apps...not support secret group communications. Furthermore, access to such social networks via mobile platforms raises a series of concerns like leakage of...not support secret group communications. Furthermore, access to such social networks via mobile platforms raises a series of concerns like leakage of

  4. Experimental realization of a highly secure chaos communication under strong channel noise

    International Nuclear Information System (INIS)

    Ye Weiping; Dai Qionglin; Wang Shihong; Lu Huaping; Kuang Jinyu; Zhao Zhenfeng; Zhu Xiangqing; Tang Guoning; Huang Ronghuai; Hu Gang

    2004-01-01

    A one-way coupled spatiotemporally chaotic map lattice is used to construct cryptosystem. With the combinatorial applications of both chaotic computations and conventional algebraic operations, our system has optimal cryptographic properties much better than the separative applications of known chaotic and conventional methods. We have realized experiments to practice duplex voice secure communications in realistic Wired Public Switched Telephone Network by applying our chaotic system and the system of Advanced Encryption Standard (AES), respectively, for cryptography. Our system can work stably against strong channel noise when AES fails to work

  5. Experimental realization of a highly secure chaos communication under strong channel noise

    Science.gov (United States)

    Ye, Weiping; Dai, Qionglin; Wang, Shihong; Lu, Huaping; Kuang, Jinyu; Zhao, Zhenfeng; Zhu, Xiangqing; Tang, Guoning; Huang, Ronghuai; Hu, Gang

    2004-09-01

    A one-way coupled spatiotemporally chaotic map lattice is used to construct cryptosystem. With the combinatorial applications of both chaotic computations and conventional algebraic operations, our system has optimal cryptographic properties much better than the separative applications of known chaotic and conventional methods. We have realized experiments to practice duplex voice secure communications in realistic Wired Public Switched Telephone Network by applying our chaotic system and the system of Advanced Encryption Standard (AES), respectively, for cryptography. Our system can work stably against strong channel noise when AES fails to work.

  6. Reliability Analysis Techniques for Communication Networks in Nuclear Power Plant

    International Nuclear Information System (INIS)

    Lim, T. J.; Jang, S. C.; Kang, H. G.; Kim, M. C.; Eom, H. S.; Lee, H. J.

    2006-09-01

    The objectives of this project is to investigate and study existing reliability analysis techniques for communication networks in order to develop reliability analysis models for nuclear power plant's safety-critical networks. It is necessary to make a comprehensive survey of current methodologies for communication network reliability. Major outputs of this study are design characteristics of safety-critical communication networks, efficient algorithms for quantifying reliability of communication networks, and preliminary models for assessing reliability of safety-critical communication networks

  7. Predicting Employee Turnover from Communication Networks.

    Science.gov (United States)

    Feeley, Thomas H.; Barnett, George A.

    1997-01-01

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

  8. 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

  9. 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

  10. 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.

  11. COMMUNICATION MANAGEMENT CRISIS IN SOCIAL NETWORKS

    OpenAIRE

    Ana Mª Enrique Jiménez

    2013-01-01

    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...

  12. Fairness in Communication and Computer Network Design

    OpenAIRE

    Nilsson, Pål

    2006-01-01

    In communication networks, fair sharing of resources is an important issue for one main reason. The growth of network capacity is in general not matching the rapid growth of traffic. Consequently, the resources consumed by each user have to be limited. This implies that users cannot always be assigned the end-to-end bandwidth they ask for. Instead, the limited network resources should be distributed to users in a way that assures fair end-to-end bandwidth assignment among them. Obtaini...

  13. Crosstalk in WDM communication networks

    NARCIS (Netherlands)

    Tafur Monroy, I.; Tangdiongga, E.

    2002-01-01

    The use of advanced transmission and switching techniques such as reconfigurable WDM optical crossconnects is enabling high capacity and flexible optical networking at ultra bit-rates reaching multi-terabits per second. These techniques also offer creative ways to improve the network connectivity

  14. Future networks and technologies supporting innovative communications

    DEFF Research Database (Denmark)

    Prasad, Ramjee

    2012-01-01

    -communications (WISDOM) that combines the aspects of personal- and cognitive radio- networks to let seamlessly bridge the virtual and physical worlds offering a constant level of all-senses, context-based, rich communication experience over fixed and wireless networks for the end users while realizing a new generation......Within a fully interconnected world, the distinct relationship between end users, consumers and providers rapidly changes towards a scenario of collaboration and competition of multiple parties within one system. ‘Convergence’, ‘ubiquitous’ and ‘smart’ are key words describing future networks...

  15. 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.

  16. 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

  17. 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

  18. 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)

  19. System Design for Nano-Network Communications

    Science.gov (United States)

    ShahMohammadian, Hoda

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

  20. 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...... combinations of nodes in which at least three nodes are located around a reference node in a configuration satisfying similarity criteria to an idealised star configuration, wherein an idealised star configuration comprises three nodes evenly angularly distributed around, and at the same distance from......, 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...

  1. Modeling MAC layer for powerline communications networks

    Science.gov (United States)

    Hrasnica, Halid; Haidine, Abdelfatteh

    2001-02-01

    The usage of electrical power distribution networks for voice and data transmission, called Powerline Communications, becomes nowadays more and more attractive, particularly in the telecommunication access area. The most important reasons for that are the deregulation of the telecommunication market and a fact that the access networks are still property of former monopolistic companies. In this work, first we analyze a PLC network and system structure as well as a disturbance scenario in powerline networks. After that, we define a logical structure of the powerline MAC layer and propose the reservation MAC protocols for the usage in the PLC network which provides collision free data transmission. This makes possible better network utilization and realization of QoS guarantees which can make PLC networks competitive to other access technologies.

  2. Communication Buses and Protocols for Sensor Networks

    Directory of Open Access Journals (Sweden)

    Andrew Mason

    2002-07-01

    Full Text Available This paper overviews existing digital communication buses which are commonly used in sensor networks, discusses sensor network architectures, and introduces a new sensor bus for low power microsystem applications. The new intra-module multi-element microsystem (IM2 bus is nine-line interface with 8b serial data which implements several advanced features such as power management and plug-n-play while maintaining minimum hardware overhead at the sensor node. Finally, some issues in wireless sensor networking are discussed. The coverage of these issues provides a guideline for choosing the appropriate bus for different sensor network applications.

  3. The entire network topology display system of terminal communication access network

    OpenAIRE

    An Yi

    2016-01-01

    Now order terminal communication access network is network technology in Shanxi Province is diversiform, device type complex, lack of unified technical standard, the terminal communication access network management system of construction constitutes a great obstacle. Need to build a “unified communication interface and communication standard, unified communications network management” of the terminal communication access network cut in the integrated network management system, for the termina...

  4. 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

  5. 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)

  6. Communication networks for medical image transmission

    International Nuclear Information System (INIS)

    Lemke, H.U.

    1993-01-01

    Digital communication networks are of increasing importance for data exchange in health care environments. They may be used to transmit multi-media data, such as text, images, graphics, signals and sound. The essential characteristics of modern network technologies are summarized in this article and are seen in the context of local, metropolitan and wide area networks. Standardized technologies discussed are Ethernet, token oriented systems, FDDI, DQDB and ATM. Off-line communication media based on magnetic optical disk, such as ISandC, are briefly introduced. The conclusion reached is that therapy planning for radiation therapy or hyperthermia can make use of communication technologies, for example, to transmit patient images, modelling data and results of distribution calculations of physical phenomena. (orig.) [de

  7. Case studies of attacks on communication networks

    International Nuclear Information System (INIS)

    Kang, Sin Bok; Han, Eon Suk

    1996-06-01

    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)

  8. VLSI Based Multiprocessor Communications Networks.

    Science.gov (United States)

    1982-09-01

    Networks". The contract began on September 1,1980 and was approved on scientific /technical grounds for a duration of three years. Incremental funding was...values for the individual delays will vary from comunicating modules (ij) are shown in Figure 4 module to module due to processing and fabrication

  9. 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

  10. 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.

  11. Interoperable Communications for Hierarchical Heterogeneous Wireless Networks

    Science.gov (United States)

    2016-04-01

    International Conference on Advanced Networks and Telecommuncations Systems (ANTS). 14-DEC-13, Kattankulathur, India. : , Husheng Li, Qi Zeng , Lijun Qian. GPS...correlation in space is too large, which implies that the correlation is overestimated. Other methods may be more accurate, faster or less memory ...limited, an intelligent mechanism is needed for the information selection and signaling design of the cross-network communication for collaborative

  12. 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.

  13. Hybrid Mobile Communication Networks for Planetary Exploration

    Science.gov (United States)

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

    2007-01-01

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

  14. 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

  15. 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 ...

  16. Finding strong lenses in CFHTLS using convolutional neural networks

    Science.gov (United States)

    Jacobs, C.; Glazebrook, K.; Collett, T.; More, A.; McCarthy, C.

    2017-10-01

    We train and apply convolutional neural networks, a machine learning technique developed to learn from and classify image data, to Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) imaging for the identification of potential strong lensing systems. An ensemble of four convolutional neural networks was trained on images of simulated galaxy-galaxy lenses. The training sets consisted of a total of 62 406 simulated lenses and 64 673 non-lens negative examples generated with two different methodologies. An ensemble of trained networks was applied to all of the 171 deg2 of the CFHTLS wide field image data, identifying 18 861 candidates including 63 known and 139 other potential lens candidates. A second search of 1.4 million early-type galaxies selected from the survey catalogue as potential deflectors, identified 2465 candidates including 117 previously known lens candidates, 29 confirmed lenses/high-quality lens candidates, 266 novel probable or potential lenses and 2097 candidates we classify as false positives. For the catalogue-based search we estimate a completeness of 21-28 per cent with respect to detectable lenses and a purity of 15 per cent, with a false-positive rate of 1 in 671 images tested. We predict a human astronomer reviewing candidates produced by the system would identify 20 probable lenses and 100 possible lenses per hour in a sample selected by the robot. Convolutional neural networks are therefore a promising tool for use in the search for lenses in current and forthcoming surveys such as the Dark Energy Survey and the Large Synoptic Survey Telescope.

  17. 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.

  18. Self-Organization in Communication Networks

    NARCIS (Netherlands)

    V. Bala; S. Goyal (Sanjeev)

    1997-01-01

    textabstractWe develop a dynamic model to study the formation of communication networks. In this model, individuals periodically make decisions concerning the continuation of existing information links and the formation of new information links, with their cohorts. These decisions trade off the

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

    African Journals Online (AJOL)

    AJRH Managing Editor

    Tanzania; 2Centre for International Development Initiatives Nijmegen (CIDIN) and ... demographic variables, social networks, knowledge and communication among the couples, whereby a stratified sample of 440 ..... FP method varies with urban- rural and regional ...... Pile JM and Simbakalia C. Tanzania Case Study: A.

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

    African Journals Online (AJOL)

    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 communication among the couples, whereby a stratified sample of 440 women of reproductive age (18-49), married or cohabiting was studied in ...

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

    African Journals Online (AJOL)

    Objective: To investigate distinctive communications through social networks which may be associated with population behaviour changes and HIV prevalence declines in Uganda compared to other countries. Methods: We undertook a comparative analysis of demographic and HIV behavioural data collected in ...

  2. 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 ...

  3. 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

  4. 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

  5. Achieving Crossed Strong Barrier Coverage in Wireless Sensor Network.

    Science.gov (United States)

    Han, Ruisong; Yang, Wei; Zhang, Li

    2018-02-10

    Barrier coverage has been widely used to detect intrusions in wireless sensor networks (WSNs). It can fulfill the monitoring task while extending the lifetime of the network. Though barrier coverage in WSNs has been intensively studied in recent years, previous research failed to consider the problem of intrusion in transversal directions. If an intruder knows the deployment configuration of sensor nodes, then there is a high probability that it may traverse the whole target region from particular directions, without being detected. In this paper, we introduce the concept of crossed barrier coverage that can overcome this defect. We prove that the problem of finding the maximum number of crossed barriers is NP-hard and integer linear programming (ILP) is used to formulate the optimization problem. The branch-and-bound algorithm is adopted to determine the maximum number of crossed barriers. In addition, we also propose a multi-round shortest path algorithm (MSPA) to solve the optimization problem, which works heuristically to guarantee efficiency while maintaining near-optimal solutions. Several conventional algorithms for finding the maximum number of disjoint strong barriers are also modified to solve the crossed barrier problem and for the purpose of comparison. Extensive simulation studies demonstrate the effectiveness of MSPA.

  6. 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.

  7. 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.

  8. Data communication network at the ASRM facility

    Science.gov (United States)

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

    1993-08-01

    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.

  9. Secure Communication in Vehicular Networks - PRESERVE Demo

    NARCIS (Netherlands)

    Lagana, M.; Feiri, Michael; Sall, M.; Lange, M.; Tomatis, A.; Papadimitratos, P.

    2012-01-01

    Security and privacy are fundamental prerequisites for the deployment of vehicular communications. The near-deployment status of Safety Applications for Intelligent Transport Systems (ITS) calls for strong evidence on the applicability of proposed research solutions, notably close-to-reality

  10. 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.

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

    KAUST Repository

    Alammouri, Ahmad

    2016-01-01

    /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

  12. Communication via an entangled coherent quantum network

    Energy Technology Data Exchange (ETDEWEB)

    El Allati, A; Hassouni, Y [Faculte des Sciences, Departement de Physique, Laboratoire de Physique Theorique URAC 13, Universite Mohammed V Agdal Rabat, Avenue Ibn Battouta, B.P. 1014, Rabat (Morocco); Metwally, N, E-mail: Nmetwally@gmail.com [Mathematics Department, College of Science, University of Bahrain, PO Box 32038 (Bahrain)

    2011-06-01

    A quantum network (QN) is constructed via maximum entangled coherent states. The possibility of using this network to achieve quantum communication between multi-participants is investigated. We showed that the probability of the successful teleportation of an unknown state depends on the size of the used network. As the number of participants increases, the success probability does not depend on the intensity of the field. Implementing a quantum teleportation protocol via a noisy QN is discussed. The unknown state can be teleported perfectly with small values of the field intensity and larger values of the noise strength. The success probability of this suggested protocol increases abruptly for larger values of the noise strength and gradually for small values. For small-size QNs, the fidelity of the teleported state decreases smoothly, whereas it decreases abruptly for larger-sized networks.

  13. Towards risk-aware communications networking

    International Nuclear Information System (INIS)

    Chołda, Piotr; Følstad, Eirik L.; Helvik, Bjarne E.; Kuusela, Pirkko; Naldi, Maurizio; Norros, Ilkka

    2013-01-01

    We promote introduction of risk-awareness in the design and operation of communications networks and services. This means explicit and systematic consideration of uncertainties related to improper behavior of the web of interdependent networks and the resulting consequences for individuals, companies and a society as a whole. Central activities are the recognition of events challenging dependability together with the assessment of their probabilities and impacts. While recognizing the complex technical, business and societal issues, we employ an overall risk framing approach containing risk assessment, response and monitoring. Our paradigm gathers topics that are currently dispersed in various fields of network activities. We review the current state of risk-related activities in networks, identify deficiencies and challenges, and suggest techniques, procedures, and metrics towards higher risk-awareness.

  14. Scaling of load in communications networks.

    Science.gov (United States)

    Narayan, Onuttom; Saniee, Iraj

    2010-09-01

    We show that the load at each node in a preferential attachment network scales as a power of the degree of the node. For a network whose degree distribution is p(k)∼k{-γ} , we show that the load is l(k)∼k{η} with η=γ-1 , implying that the probability distribution for the load is p(l)∼1/l{2} independent of γ . The results are obtained through scaling arguments supported by finite size scaling studies. They contradict earlier claims, but are in agreement with the exact solution for the special case of tree graphs. Results are also presented for real communications networks at the IP layer, using the latest available data. Our analysis of the data shows relatively poor power-law degree distributions as compared to the scaling of the load versus degree. This emphasizes the importance of the load in network analysis.

  15. 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

  16. 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.

  17. 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

  18. 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.)

  19. Resource Management in Broadband Communication Networks

    DEFF Research Database (Denmark)

    Hansen, Mads Stenhuus

    2003-01-01

    . The first part gives a brief description of some of the existing protocols for routing and controlling resources, such as RSVP, OSPF, BGP, PNNI, etc. The remaining part concerns the following two fundamentally different approaches to resource management etc.: - Software agents - Simulated ants......This thesis - Resource Management in Broadband Communication Networks - deals with different ways of optimizing the available resources of data- or telecommunication networks. Especially topics like optimal routing, load balancing and fast recovery of routes in case of link failures are covered...

  20. 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

  1. An FPGA-based torus communication network

    Energy Technology Data Exchange (ETDEWEB)

    Pivanti, Marcello; Schifano, Sebastiano Fabio [INFN, Ferrara (Italy); Ferrara Univ. (Italy); Simma, Hubert [DESY, Zeuthen (Germany). John von Neumann-Institut fuer Computing NIC

    2011-02-15

    We describe the design and FPGA implementation of a 3D torus network (TNW) to provide nearest-neighbor communications between commodity multi-core processors. The aim of this project is to build up tightly interconnected and scalable parallel systems for scientific computing. The design includes the VHDL code to implement on latest FPGA devices a network processor, which can be accessed by the CPU through a PCIe interface and which controls the external PHYs of the physical links. Moreover, a Linux driver and a library implementing custom communication APIs are provided. The TNW has been successfully integrated in two recent parallel machine projects, QPACE and AuroraScience. We describe some details of the porting of the TNW for the AuroraScience system and report performance results. (orig.)

  2. An FPGA-based torus communication network

    International Nuclear Information System (INIS)

    Pivanti, Marcello; Schifano, Sebastiano Fabio; Simma, Hubert

    2011-02-01

    We describe the design and FPGA implementation of a 3D torus network (TNW) to provide nearest-neighbor communications between commodity multi-core processors. The aim of this project is to build up tightly interconnected and scalable parallel systems for scientific computing. The design includes the VHDL code to implement on latest FPGA devices a network processor, which can be accessed by the CPU through a PCIe interface and which controls the external PHYs of the physical links. Moreover, a Linux driver and a library implementing custom communication APIs are provided. The TNW has been successfully integrated in two recent parallel machine projects, QPACE and AuroraScience. We describe some details of the porting of the TNW for the AuroraScience system and report performance results. (orig.)

  3. 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

  4. Research on optic antenna of space laser communication networking

    Science.gov (United States)

    Meng, Li-Xin; Li, Long; Zhang, Li-zhong; Zhao, Shan-shan; Jiang, Hui-lin

    2013-08-01

    With the highlights of the high transmission rate, large capacity, strong anti-interference and anti-capture ability, good security and small light, space laser communication becomes an important hotspot. At present, the focus of research of the laser communication system is point to point communication structure. However, from the application point of view, both the realization of space laser communication among multiple points and the establishment of the information transmission network can really have the practical value. Aiming at the problem of space laser communication network, this article puts forward the general idea about optical antenna to achieve multiple tracking goals at the same time. Through the analysis of the optical antenna, and the comparing of the current commonly used mirror driving mechanism, a new mirror driving mechanism is designed. The azimuth motion, containing circular grating feedback, is driven by torque motor,voice coil motor of fan produces pitch motion that has fan-shaped grating feedback, so that compression of the structure size to improve the efficiency of the reflector assembly. Through the establishment of the driving mechanism and the kinematic model of 3D entity, the relationship between the single drive azimuth and pitch angle following the angle of incident light is explained. The biggest ideal view area affecting the optical antenna is obtained by the simulation analysis of the kinematics model using MATLAB. The several factors of field overlap area and blind area offers a theoretical basis for structure optimization and control system for the subsequent optical antenna design.

  5. Understanding communication networks in the emergency department

    Directory of Open Access Journals (Sweden)

    Braithwaite Jeffrey

    2009-12-01

    Full Text Available Abstract Background Emergency departments (EDs are high pressure health care settings involving complex interactions between staff members in providing and organising patient care. Without good communication and cooperation amongst members of the ED team, quality of care is at risk. This study examined the problem-solving, medication advice-seeking and socialising networks of staff working in an Australian hospital ED. Methods A social network survey (Response Rate = 94% was administered to all ED staff (n = 109 including doctors, nurses, allied health professionals, administrative staff and ward assistants. Analysis of the network characteristics was carried out by applying measures of density (the extent participants are concentrated, connectedness (how related they are, isolates (how segregated, degree centrality (who has most connections measured in two ways, in-degree, the number of ties directed to an individual and out-degree, the number of ties directed from an individual, betweenness centrality (who is important or powerful, degree of separation (how many ties lie between people and reciprocity (how bi-directional are interactions. Results In all three networks, individuals were more closely connected to colleagues from within their respective professional groups. The problem-solving network was the most densely connected network, followed by the medication advice network, and the loosely connected socialising network. ED staff relied on each other for help to solve work-related problems, but some senior doctors, some junior doctors and a senior nurse were important sources of medication advice for their ED colleagues. Conclusions Network analyses provide useful ways to assess social structures in clinical settings by allowing us to understand how ED staff relate within their social and professional structures. This can provide insights of potential benefit to ED staff, their leaders, policymakers and researchers.

  6. The use of electronic communication (social network) by open and ...

    African Journals Online (AJOL)

    The use of electronic communication (social network) by open and distance students, ... ODL students use face book and whatsapps as their preferred social networks. ... networks distract academic studies and it is expensive to use, also more ...

  7. 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.

  8. Renewal of K-NET (National Strong-motion Observation Network of Japan)

    Science.gov (United States)

    Kunugi, T.; Fujiwara, H.; Aoi, S.; Adachi, S.

    2004-12-01

    The National Research Institute for Earth Science and Disaster Prevention (NIED) operates K-NET (Kyoshin Network), the national strong-motion observation network, which evenly covers the whole of Japan at intervals of 25 km on average. K-NET was constructed after the Hyogoken-Nambu (Kobe) earthquake in January 1995, and began operation in June 1996. Thus, eight years have passed since K-NET started, and large amounts of strong-motion records have been obtained. As technology has progressed and new technologies have become available, NIED has developed a new K-NET with improved functionality. New seismographs have been installed at 443 observatories mainly in southwestern Japan where there is a risk of strong-motion due to the Nankai and Tonankai earthquakes. The new system went into operation in June 2004, although seismographs have still to be replaced in other areas. The new seismograph (K-NET02) consists of a sensor module, a measurement module and a communication module. A UPS, a GPS antenna and a dial-up router are also installed together with a K-NET02. A triaxial accelerometer, FBA-ES-DECK (Kinemetrics Inc.) is built into the sensor module. The measurement module functions as a conventional strong-motion seismograph for high-precision observation. The communication module can perform sophisticated processes, such as calculation of the Japan Meteorological Agency (JMA) seismic intensity, continuous recording of data and near real-time data transmission. It connects to the Data Management Center (DMC) using an ISDN line. In case of a power failure, the measurement module can control the power supply to the router and the communication module to conserve battery power. One of the main features of K-NET02 is a function for processing JMA seismic intensity. K-NET02 functions as a proper seismic intensity meter that complies with the official requirements of JMA, although the old strong-motion seismograph (K-NET95) does not calculate seismic intensity. Another

  9. 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.

  10. 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.

  11. Extracting Association Patterns in Network Communications

    Science.gov (United States)

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

    2015-01-01

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

  12. 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.

  13. 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.

  14. 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.

  15. Manual for WSPEEDI international data communication network

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Masatoshi; Nagai, Haruyasu; Chino, Masamichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2000-09-01

    Japan Atomic Energy Research Institute has developed a computer-based dose prediction system WSPEEDI (System for Prediction of Environmental Emergency Dose Information) for predicting the radiological impacts on the Japanese people of a nuclear accident abroad to meet the requirement caused by the Chernobyl accident. Because WSPEEDI reached on the practical stage through several verification studies, the development of international data communication network is started to exchange modeling products and environmental data quickly. This manual describes registration, search and management of modeling products and environmental data and handling of tele-conference tool. (author)

  16. 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.

  17. Communication security in open health care networks.

    Science.gov (United States)

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

    1999-01-01

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

  18. Performance testing framework for smart grid communication network

    International Nuclear Information System (INIS)

    Quang, D N; See, O H; Chee, L L; Xuen, C Y; Karuppiah, S

    2013-01-01

    Smart grid communication network is comprised of different communication mediums and technologies. Performance evaluation is one of the main concerns in smart grid communication system. In any smart grid communication implementation, to determine the performance factor of the network, a testing of an end-to-end process flow is required. Therefore, an effective and coordinated testing procedure plays a crucial role in evaluating the performance of smart grid communications. In this paper, a testing framework is proposed as a guideline to analyze and assess the performance of smart grid communication network.

  19. 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.

  20. 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.

  1. 77 FR 35711 - Strong Cities, Strong Communities National Resource Network Pilot Program Advance Notice and...

    Science.gov (United States)

    2012-06-14

    ... economic need, strong local leadership and collaboration, potential for economic growth, geographic... $1 million that they will use to administer an ``X-prize style'' competition, whereby they will... founding mandate in the 1965 Department of Housing and Urban Development Act to ``Exercise leadership at...

  2. fraud detection in mobile communications networks using user

    African Journals Online (AJOL)

    DEPT OF AGRICULTURAL ENGINEERING

    testing the methods with data from real mobile communications networks. Keywords: Call .... System. Monitoring. Database. Database. Fig. 3: Mobile communication detection tools ..... receiver operating characteristic curve (ROC). ROC is a ...

  3. 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

    Off-the shelf wireless communication technologies reduce infrastructure deployment costs and are thus attractive for distribution system control. Wireless communication however may lead to variable network performance. Hence the impact of this variability on overall distribution system control be...

  4. 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

  5. Integration versus Outsourcing in Stable Industry Equilibrium with Communication Networks

    OpenAIRE

    Okamoto, Yusuke

    2006-01-01

    For the selection of a firm's structure between vertical integration and arm's-length outsourcing, the importance of the thickness of the market had been emphasized in the previous literature. Here we take account of communication networks such as telephone, telex, fax, and the Internet. By doing so, we could illustrate the relationship between communication networks and the make-or-buy decision. With communication network technology differing in each type of firm, both vertically integrated ...

  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. 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

  8. 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.

  9. fraud detection in mobile communications networks using user

    African Journals Online (AJOL)

    DEPT OF AGRICULTURAL ENGINEERING

    Fraud detection is an important application, since network operators lose a relevant portion of their revenue to fraud. ... testing the methods with data from real mobile communications networks. Keywords: Call data, fraud ...... Ph. D. thesis. Pur-.

  10. Communication and cooperation in underwater acoustic networks

    Science.gov (United States)

    Yerramalli, Srinivas

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

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

    Science.gov (United States)

    Kihara, Masami; Imaoka, Atsushi

    1990-01-01

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

  12. 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.

  13. Modeling And Simulation Of Multimedia Communication Networks

    Science.gov (United States)

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

    1989-05-01

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

  14. 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...

  15. Communication networks beyond the capacity crunch.

    Science.gov (United States)

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

    2016-03-06

    This issue of Philosophical Transactions of the Royal Society, Part A represents a summary of the recent discussion meeting 'Communication networks beyond the capacity crunch'. The purpose of the meeting was to establish the nature of the capacity crunch, estimate the time scales associated with it and to begin to find solutions to enable continued growth in a post-crunch era. The meeting confirmed that, in addition to a capacity shortage within a single optical fibre, many other 'crunches' are foreseen in the field of communications, both societal and technical. Technical crunches identified included the nonlinear Shannon limit, wireless spectrum, distribution of 5G signals (front haul and back haul), while societal influences included net neutrality, creative content generation and distribution and latency, and finally energy and cost. The meeting concluded with the observation that these many crunches are genuine and may influence our future use of technology, but encouragingly noted that research and business practice are already moving to alleviate many of the negative consequences. © 2016 The Authors.

  16. 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.

  17. The Dynamics of Initiative in Communication Networks.

    Directory of Open Access Journals (Sweden)

    Anders Mollgaard

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

  18. The Role of Middlemen inEfficient and Strongly Pairwise Stable Networks

    NARCIS (Netherlands)

    Gilles, R.P.; Chakrabarti, S.; Sarangi, S.; Badasyan, N.

    2004-01-01

    We examine the strong pairwise stability concept in network formation theory under collective network benefits.Strong pairwise stability considers a pair of players to add a link through mutual consent while permitting them to unilaterally delete any subset of links under their control.We examine

  19. 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

  20. 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

  1. Ethernet image communication performance in a multimodal PACS network

    International Nuclear Information System (INIS)

    Lou, S.L.; Valentino, D.J.; Chan, K.K.; Huang, H.K.

    1989-01-01

    The authors have evaluated the performance of an Ethernet network in a multimodal picture archiving and communications system (PACS) environment. The study included measurements between Sun workstations and PC- AT computers running communication software at the TCP level. First they initiated image transfers between two workstations, a server and a client. Next, they successively added clients to transfer images to the server and they measured degradation in network performance. Finally, they initiated image transfers between pairs of workstations and again measured performance degradation. The results of the authors' experiments indicate that Ethernet is suitable for image communication only in limited network situations. They discuss how to maximize network performance given these constraints

  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

    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.

  4. Validation of Bosch' Mobile Communication NetworkArchitecture with SPIN

    NARCIS (Netherlands)

    Ruys, T.C.; Langerak, Romanus

    This paper discusses validation projects carried out for the Mobile Communication Division of Robert Bosch GmbH. We verified parts of their Mobile Communication Network (MCNet), a communication system which is to be used in infotainment systems of future cars. The protocols of the MCNet have been

  5. 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 as...

  6. 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...... cases. By the example of the Gedda-Headz gaming community, possible links between cooperative mobile communication and social mobile networks are shown....

  7. 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.

  8. Leveraging the NPS Femto Satellite for Alternative Satellite Communication Networks

    Science.gov (United States)

    2017-09-01

    programmed for eventual integration with the Iridium Network , which is then tested. C. THESIS ORGANIZATION The thesis addresses these questions...NPS FEMTO SATELLITE FOR ALTERNATIVE SATELLITE COMMUNICATION NETWORKS by Faisal S. Alshaya September 2017 Co-Advisors: Steven J. Iatrou...TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE LEVERAGING THE NPS FEMTO SATELLITE FOR ALTERNATIVE SATELLITE COMMUNICATION NETWORKS 5

  9. 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…

  10. E-SAP: efficient-strong authentication protocol for healthcare applications using wireless medical sensor networks.

    Science.gov (United States)

    Kumar, Pardeep; Lee, Sang-Gon; Lee, Hoon-Jae

    2012-01-01

    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.

  11. 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.

  12. Communication on the structure of biological networks

    Indian Academy of Sciences (India)

    Introduction. Over the past few years, network science has drawn attention from a large number of ... The qualitative properties of biological networks cannot ... Here, we study the underlying undirected structure of empirical biological networks.

  13. 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

  14. 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

  15. 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.

  16. Complex networks in the Euclidean space of communicability distances

    Science.gov (United States)

    Estrada, Ernesto

    2012-06-01

    We study the properties of complex networks embedded in a Euclidean space of communicability distances. The communicability distance between two nodes is defined as the difference between the weighted sum of walks self-returning to the nodes and the weighted sum of walks going from one node to the other. We give some indications that the communicability distance identifies the least crowded routes in networks where simultaneous submission of packages is taking place. We define an index Q based on communicability and shortest path distances, which allows reinterpreting the “small-world” phenomenon as the region of minimum Q in the Watts-Strogatz model. It also allows the classification and analysis of networks with different efficiency of spatial uses. Consequently, the communicability distance displays unique features for the analysis of complex networks in different scenarios.

  17. Using Social Network Analysis to Investigate Positive EOL Communication.

    Science.gov (United States)

    Xu, Jiayun; Yang, Rumei; Wilson, Andrew; Reblin, Maija; Clayton, Margaret F; Ellington, Lee

    2018-04-30

    End of life (EOL) communication is a complex process involving the whole family and multiple care providers. Applications of analysis techniques that account for communication beyond the patient and patient/provider, will improve clinical understanding of EOL communication. To introduce the use of social network analysis to EOL communication data, and to provide an example of applying social network analysis to home hospice interactions. We provide a description of social network analysis using social network analysis to model communication patterns during home hospice nursing visits. We describe three social network attributes (i.e. magnitude, directionality, and reciprocity) in the expression of positive emotion among hospice nurses, family caregivers, and hospice cancer patients. Differences in communication structure by primary family caregiver gender and across time were also examined. Magnitude (frequency) in the expression of positive emotion occurred most often between nurses and caregivers or nurses and patients. Female caregivers directed more positive emotion to nurses, and nurses directed more positive emotion to other family caregivers when the primary family caregiver was male. Reciprocity (mutuality) in positive emotion declined towards day of death, but increased on day of actual patient death. There was variation in reciprocity by the type of positive emotion expressed. Our example demonstrates that social network analysis can be used to better understand the process of EOL communication. Social network analysis can be expanded to other areas of EOL research, such as EOL decision-making and health care teamwork. Copyright © 2018. Published by Elsevier Inc.

  18. Research of the key technology in satellite communication networks

    Science.gov (United States)

    Zeng, Yuan

    2018-02-01

    According to the prediction, in the next 10 years the wireless data traffic will be increased by 500-1000 times. Not only the wireless data traffic will be increased exponentially, and the demand for diversified traffic will be increased. Higher requirements for future mobile wireless communication system had brought huge market space for satellite communication system. At the same time, the space information networks had been greatly developed with the depth of human exploration of space activities, the development of space application, the expansion of military and civilian application. The core of spatial information networks is the satellite communication. The dissertation presented the communication system architecture, the communication protocol, the routing strategy, switch scheduling algorithm and the handoff strategy based on the satellite communication system. We built the simulation platform of the LEO satellites networks and simulated the key technology using OPNET.

  19. 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

  20. 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.

  1. 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.

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

    International Nuclear Information System (INIS)

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

    2010-01-01

    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. (general)

  3. 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

  4. Communication networks and spatial ecology in nightingales

    NARCIS (Netherlands)

    Naguib, M.; Kunc, H.P.; Sprau, P.; Roth, T.; Amrhein, V.

    2011-01-01

    In most animals, communication plays a central role in a variety of contexts. In this chapter, we synthesize studies on vocal communication and spatial behavior in nightingales, Luscinia megarhynchos, with other research on songbirds to emphasize the need to integrate studies on communication with

  5. 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.

  6. PG&E's Seismic Network Goes Digital With Strong Motion: Successes and Challenges

    Science.gov (United States)

    Stanton, M. A.; Cullen, J.; McLaren, M. K.

    2008-12-01

    Pacific Gas and Electric Company (PG&E) is in year 3 of a 5-year project to upgrade the Central Coast Seismic Network (CCSN) from analog to digital. Located along the south-central California coast, the CCSN began operation in 1987, with 20 analog stations; 15 vertical component and 5 dual gain 3-component S-13 sensors. The analog signals travel over FM radio telemetry links and voice channels via PG&E's microwave network to our facility in San Francisco (SF), where the A/D conversion is performed on a computer running Earthworm v7.1, which also transmits the data to the USGS in Menlo Park. At the conversion point the dynamic ranges of the vertical and dual-gain sensors are 40-50dB and 60-70dB, respectively. Dynamic range exceedance (data clipping) generally occurs for a M2.5 or greater event within about 40 km of a station. The motivations to upgrade the seismic network were the need for higher dynamic range and to retire obsolete analog transmission equipment. The upgraded digital stations consist of the existing velocity sensors, a 131A-02/3 accelerometer and a Reftek 130-01 Broadband Seismic Recorder for digital data recording and transmission to SF. Vertical only stations have one component of velocity and 3 components of acceleration. Dual gain sites have 3 components of velocity and 3 of acceleration. To date we have successfully upgraded 6 sites; 3 more will be installed by the end of 2008. Some of the advantages of going digital are 1) data is recorded at each site and in SF, 2) substantially increased dynamic range of the velocity sensors to 120dB, as observed by on scale, close-by recordings from a M3.9 San Simeon aftershock on 04/29/2008, 3) accelerometers for on scale recording of large earthquakes, and 4) ability to contribute our strong motion data to USGS ShakeMaps. A significant challenge has been consistent radio communications. To resolve this issue we are installing point-to-multipoint Motorola Canopy spread spectrum radios at the stations and

  7. Advanced Communication and Networking Technologies for Mars Exploration

    Science.gov (United States)

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

    2001-01-01

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

  8. Northern emporia and maritime networks. Modelling past communication using archaeological network analysis

    DEFF Research Database (Denmark)

    Sindbæk, Søren Michael

    2015-01-01

    preserve patterns of thisinteraction. Formal network analysis and modelling holds the potential to identify anddemonstrate such patterns, where traditional methods often prove inadequate. Thearchaeological study of communication networks in the past, however, calls for radically different analytical...... this is not a problem of network analysis, but network synthesis: theclassic problem of cracking codes or reconstructing black-box circuits. It is proposedthat archaeological approaches to network synthesis must involve a contextualreading of network data: observations arising from individual contexts, morphologies...

  9. A network architecture for International Business Satellite communications

    Science.gov (United States)

    Takahata, Fumio; Nohara, Mitsuo; Takeuchi, Yoshio

    Demand Assignment (DA) control is expected to be introduced in the International Business Satellte communications (IBS) network in order to cope with a growing international business traffic. The paper discusses the DA/IBS network from the viewpoints of network configuration, satellite channel configuration and DA control. The network configuration proposed here consists of one Central Station with network management function and several Network Coordination Stations with user management function. A satellite channel configuration is also presented along with a tradeoff study on transmission bit rate, high power amplifier output power requirement, and service quality. The DA control flow and protocol based on CCITT Signalling System No. 7 are also proposed.

  10. 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)

  11. Tactical Voice Communications Over Shipboard Local Area Networks

    National Research Council Canada - National Science Library

    Urie, Glenn

    2001-01-01

    The United States Navy's next generation ship(s) scheduled for commissioning in the year 2004 and beyond will integrate tactical shipboard voice communications system into the local area network (LAN...

  12. 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...

  13. Stabilization of Networked Control Systems Under Feedback-based Communication

    National Research Council Canada - National Science Library

    Zhang, Lei; Hristu-Varsakelis, Dimitrios

    2004-01-01

    We study the stabilization of a networked control system (NSC) in which multiple sensors and actuators of a physical plant share a communication medium to exchange information with a remote controller...

  14. 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...

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

    Science.gov (United States)

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

    2016-08-01

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

  16. 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..

  17. Successive lag synchronization on dynamical networks with communication delay

    International Nuclear Information System (INIS)

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

    2016-01-01

    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. (paper)

  18. 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.

  19. 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.......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...

  20. Design of Hybrid Mobile Communication Networks for Planetary Exploration

    Science.gov (United States)

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

    2004-01-01

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

  1. 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.

  2. Emergency Communications Network for Disasters Management in Venezuela

    Science.gov (United States)

    Burguillos, C.; Deng, H.

    2018-04-01

    The integration and use of different space technology applications for disasters management, play an important role at the time of prevents the causes and mitigates the effects of the natural disasters. Nevertheless, the space technology counts with the appropriate technological resources to provide the accurate and timely information required to support in the decision making in case of disasters. Considering the aforementioned aspects, in this research is presented the design and implementation of an Emergency Communications Network for Disasters Management in Venezuela. Network based on the design of a topology that integrates the satellites platforms in orbit operation under administration of Venezuelan state, such as: the communications satellite VENESAT-1 and the remote sensing satellites VRSS-1 and VRSS-2; as well as their ground stations with the aim to implement an emergency communications network to be activated in case of disasters which affect the public and private communications infrastructures in Venezuela. In this regard, to design the network several technical and operational specifications were formulated, between them: Emergency Strategies to Maneuver the VRSS-1 and VRSS-2 satellites for optimal images capture and processing, characterization of the VENESAT-1 transponders and radiofrequencies for emergency communications services, technologies solutions formulation and communications links design for disaster management. As result, the emergency network designed allows to put in practice diverse communications technologies solutions and different scheme or media for images exchange between the areas affected for disasters and the entities involved in the disasters management tasks, providing useful data for emergency response and infrastructures recovery.

  3. 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

  4. 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.

  5. The communications model of using social network by sports clubs

    OpenAIRE

    S. Kowalski

    2012-01-01

    This article presents a model of marketing communications using social network by sports clubs. It presents the links between the sports club and its environment and uses of the Internet to promote it. The model of communication is composed of the elements responsible for the success of marketing in the web. Article also includes recommendations for using the model in practice.

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

    Science.gov (United States)

    Farace, Richard V.; Danowski, James A.

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

  7. 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 ...

  8. 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 such performance maps. We demonstrate how the framework can be used to reduce the retransmissions and to better utilise network resources when performing TCP-based file downloads in vehicular M2M communication scenarios. The approach works on top of a standard TCP stack hence has to map identified transmission...

  9. 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.

  10. 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.

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

    Science.gov (United States)

    2013-01-01

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

  12. Human-Centric Wireless Communication Networks

    OpenAIRE

    Cavallari, Riccardo

    2016-01-01

    This thesis covers two main topics: the design and performance evaluation of Wireless Body Area Networks (WBANs), and the simulation and mathematical modeling of Delay Tolerant Networks (DTNs). Different Medium Access Control (MAC) protocols for WBANs are implemented on dedicated hardware in order to evaluate, through extensive measurement campaigns, the performance of the network in terms of packet loss rate, delay and energy consumption. Novel solutions to cope with bo...

  13. Cognitive Radio Networks for Tactical Wireless Communications

    Science.gov (United States)

    2014-12-01

    exists. Instead, security is an evolving process, as we have seen in the context of WLANs and 2G / 3G networks. New system vulnerabilities continue to...in the network configuration and radio parameters take place due to mobility of platforms, and variation in other users of the RF environment. CRNs...dynamic spectrum access experimentally, and it represents the largest military Mobile Ad hoc Network (MANET) as of today. The WNaN demonstrator has been

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

    Science.gov (United States)

    Farace, Richard V.; Johnson, Jerome David

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

  15. Real-Time Communication in Wireless Home Networks

    NARCIS (Netherlands)

    Scholten, Johan; Jansen, P.G.

    This paper describes a medium access protocol for real-time communication in wireless networks. Medium access is controlled by a scheduler, which utilizes a pre-emptive earliest deadline first (PEDF) scheduling algorithm. The scheduler prevents collisions in the network, where normally only

  16. Seamless integrated network system for wireless communication systems

    NARCIS (Netherlands)

    Wu, Gang; Mizuno, Mitsuhiko; Hase, Yoshihiro; Havinga, Paul J.M.

    2006-01-01

    To create a network that connects a plurality of wireless communication systems to create optimal systems for various environments, and that seamlessly integrates the resulting systems together in order to provide more efficient and advanced service in general. A network system that can seamlessly

  17. Seamless integrated network system for wireless communication systems

    NARCIS (Netherlands)

    Wu, Gang; Mizuno, Mitsuhiko; Hase, Yoshihiro; Havinga, Paul J.M.

    2002-01-01

    To create a network that connects a plurality of wireless communication systems to create optimal systems for various environments, and that seamlessly integrates the resulting systems together in order to provide more efficient and advanced service in general. A network system that can seamlessly

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

    Science.gov (United States)

    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.

  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. <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...

  2. Converting serial networks to Ethernet communications

    Energy Technology Data Exchange (ETDEWEB)

    Rosado, Elroy [Freewave Technologies, Inc., Boulder, CO (United States). Latin America

    2008-07-01

    Many oil and gas producers and pipeline companies find themselves in an awkward position. They have invested millions of dollars in legacy serial communications systems and in most cases, millions more in older SCADA remote terminal units and electronic flow meters. There is a desire throughout most of the industry to convert these systems to Ethernet. This presentation will explore how Ethernet protocol offers advantages over the older serial communications in terms of peer to peer communication, faster polling cycles, and the ability to poll multiple devices at the same time. (author)

  3. 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.

  4. 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.

  5. Network Coding Protocols for Smart Grid Communications

    DEFF Research Database (Denmark)

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

    2014-01-01

    We propose a robust network coding protocol for enhancing the reliability and speed of data gathering in smart grids. At the heart of our protocol lies the idea of tunable sparse network coding, which adopts the transmission of sparsely coded packets at the beginning of the transmission process b...

  6. Quantum Communication Through a Two-Dimensional Spin Network

    International Nuclear Information System (INIS)

    Wang Zhaoming; Gu Yongjian

    2012-01-01

    We investigate the state or entanglement transfer through a two-dimensional spin network. We show that for state transfer, better fidelity can be gained along the diagonal direction but for entanglement transfer, when the initial entanglement is created along the boundary, the concurrence is more inclined to propagate along the boundary. This behavior is produced by quantum mechanical interference and the communication quality depends on the precise size of the network. For some number of sites, the fidelity in a two-dimensional channel is higher than one-dimensional case. This is an important result for realizing quantum communication through high dimension spin chain networks.

  7. 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.

  8. 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 ...

  9. 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 ...

  10. 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).

  11. 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. .

  12. Efficient data communication protocols for wireless networks

    Science.gov (United States)

    Zeydan, Engin

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

  13. 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.

  14. 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

  15. 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)

  16. 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.

  17. 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...... this problem and suggests different mechanisms to support reliability as part of the MAC protocol. Analytical expressions to this problem are given to qualify the performance of the modified network coding. These expressions are confirmed by numerical result. While the suggested reliability mechanisms...

  18. Improving the physical layer security of wireless communication networks using spread spectrum coding and artificial noise approach

    CSIR Research Space (South Africa)

    Adedeji, K

    2016-09-01

    Full Text Available at the application layer to protect the messages against eavesdropping. However, the evolution of strong deciphering mechanisms has made conventional cryptography-based security techniques ineffective against attacks from an intruder. Figure 1: Layer protocol... communication networks with passive and active eavesdropper,” IEEE Globecom; Wireless Communication System, pp. 4868-4873, 2012. [9] Y. Zou, X. Wang and W. Shen, “Optimal relay selection for physical layer security in cooperative wireless networks,” IEEE...

  19. Demand Moderation in Military Communication Networks

    National Research Council Canada - National Science Library

    Blackmore, Perry

    2002-01-01

    .... Demand moderation is the term used to encompass the array of mechanisms aimed at achieving this end. Integrated Defence networks of the future should benefit enormously from demand moderation mechanisms.

  20. Advanced Communication for Wireless Sensor Networks

    Science.gov (United States)

    2016-08-22

    strategies that could be used to increase the single-hop transmission range of a wireless sensor network, increase energy efficiency (improve battery...substance placed within the reach of the network. Sensor measurements were quantized to save energy and bandwidth during transmission of the...the problem of assigning transmission powers to every node in order to maintain connectivity while minimizing the energy consumption of the whole

  1. On imperfect node protection in complex communication networks

    International Nuclear Information System (INIS)

    Xiao Shi; Xiao Gaoxi

    2011-01-01

    Motivated by recent research on complex networks, we study enhancing complex communication networks against intentional attack which takes down network nodes in a decreasing order of their degrees. Specifically, we evaluate an effect which has been largely ignored in existing studies; many real-life systems, especially communication systems, have protection mechanisms for their important components. Due to the existence of such protection, it is generally quite difficult to totally crash a protected node, though partially paralyzing it may still be feasible. Our analytical and simulation results show that such 'imperfect' protections generally speaking still help significantly enhance network robustness. Such insight may be helpful for the future developments of efficient network attack and protection schemes.

  2. 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...

  3. 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...

  4. Business communication in social networks: Content management and experiences

    Directory of Open Access Journals (Sweden)

    Miguel Ángel Nicolás

    2014-11-01

    Full Text Available Currently, management of communication in social networks has become an indispensable strategic activity and contributes directly to change the mode of relationship between business and its stakeholders. The first section of this paper presents a brief analysis of the results reported in different specialized national studies in social networks. We analyse the general activities that users prefer to do and activities that users value most brands on networks. If an organization wants to successfully manage their communication in social networks is very important to know the behaviour of the users and design strategies based on their status and economic activity. This paper presents a brief analysis of social branding through the classification of different corporate content posted on their networks.

  5. On imperfect node protection in complex communication networks

    Energy Technology Data Exchange (ETDEWEB)

    Xiao Shi [Hubei Province Key Laboratory of Intelligent Robot and School of Computer Science and Engineering, Wuhan Institute of Technology, Wuhan 430073 (China); Xiao Gaoxi, E-mail: xiao_moon2002@yahoo.com.cn, E-mail: egxxiao@ntu.edu.sg [Division of Communication Engineering, School of Electrical and Electronic Engineering, Nanyang Technological University, 639798 (Singapore)

    2011-02-04

    Motivated by recent research on complex networks, we study enhancing complex communication networks against intentional attack which takes down network nodes in a decreasing order of their degrees. Specifically, we evaluate an effect which has been largely ignored in existing studies; many real-life systems, especially communication systems, have protection mechanisms for their important components. Due to the existence of such protection, it is generally quite difficult to totally crash a protected node, though partially paralyzing it may still be feasible. Our analytical and simulation results show that such 'imperfect' protections generally speaking still help significantly enhance network robustness. Such insight may be helpful for the future developments of efficient network attack and protection schemes.

  6. 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.

  7. <strong>A Language-Based Approach for Improving the Robustness of Network Application Protocol Implementationsstrong>

    DEFF Research Database (Denmark)

    Burgy, Laurent; Reveillere, Laurent; Lawall, Julia Laetitia

    2007-01-01

    The secure and robust functioning of a network relies on the defect-free implementation of network applications. As network protocols have become increasingly complex, however, hand-writing network message processing code has become increasingly error-prone. In this paper, we present a domain...

  8. 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 ...

  9. 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.

  10. Characterizing Social Networks and Communication Channels in a Web-Based Peer Support Intervention.

    Science.gov (United States)

    Owen, Jason E; Curran, Michaela; Bantum, Erin O'Carroll; Hanneman, Robert

    2016-06-01

    Web and mobile (mHealth) interventions have promise for improving health outcomes, but engagement and attrition may be reducing effect sizes. Because social networks can improve engagement, which is a key mechanism of action, understanding the structure and potential impact of social networks could be key to improving mHealth effects. This study (a) evaluates social network characteristics of four distinct communication channels (discussion board, chat, e-mail, and blog) in a large social networking intervention, (b) predicts membership in online communities, and (c) evaluates whether community membership impacts engagement. Participants were 299 cancer survivors with significant distress using the 12-week health-space.net intervention. Social networking attributes (e.g., density and clustering) were identified separately for each type of network communication (i.e., discussion board, blog, web mail, and chat). Each channel demonstrated high levels of clustering, and being a community member in one communication channel was associated with being in the same community in each of the other channels (φ = 0.56-0.89, ps < 0.05). Predictors of community membership differed across communication channels, suggesting that each channel reached distinct types of users. Finally, membership in a discussion board, chat, or blog community was strongly associated with time spent engaging with coping skills exercises (Ds = 1.08-1.84, ps < 0.001) and total time of intervention (Ds = 1.13-1.80, ps < 0.001). mHealth interventions that offer multiple channels for communication allow participants to expand the number of individuals with whom they are communicating, create opportunities for communicating with different individuals in distinct channels, and likely enhance overall engagement.

  11. Characterizing Social Networks and Communication Channels in a Web-Based Peer Support Intervention

    Science.gov (United States)

    Curran, Michaela; Bantum, Erin O'Carroll; Hanneman, Robert

    2016-01-01

    Abstract Web and mobile (mHealth) interventions have promise for improving health outcomes, but engagement and attrition may be reducing effect sizes. Because social networks can improve engagement, which is a key mechanism of action, understanding the structure and potential impact of social networks could be key to improving mHealth effects. This study (a) evaluates social network characteristics of four distinct communication channels (discussion board, chat, e-mail, and blog) in a large social networking intervention, (b) predicts membership in online communities, and (c) evaluates whether community membership impacts engagement. Participants were 299 cancer survivors with significant distress using the 12-week health-space.net intervention. Social networking attributes (e.g., density and clustering) were identified separately for each type of network communication (i.e., discussion board, blog, web mail, and chat). Each channel demonstrated high levels of clustering, and being a community member in one communication channel was associated with being in the same community in each of the other channels (φ = 0.56–0.89, ps < 0.05). Predictors of community membership differed across communication channels, suggesting that each channel reached distinct types of users. Finally, membership in a discussion board, chat, or blog community was strongly associated with time spent engaging with coping skills exercises (Ds = 1.08–1.84, ps < 0.001) and total time of intervention (Ds = 1.13–1.80, ps < 0.001). mHealth interventions that offer multiple channels for communication allow participants to expand the number of individuals with whom they are communicating, create opportunities for communicating with different individuals in distinct channels, and likely enhance overall engagement. PMID:27327066

  12. 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)

  13. 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

  14. Demystifying communication signal lost for network redundancy ...

    African Journals Online (AJOL)

    These studies report on the communication signal lost factors that were analyzed and supported by evidences on coverage analysis activities for Automatic Meter Reading (AMR) systems. We have categorized the influential signal lost factors into four core elements that were concluded based on our field measurement ...

  15. 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.

  16. Close encounters: Analyzing how social similarity and propinquity contribute to strong network connections.

    OpenAIRE

    Reagans, Ray Eugene

    2010-01-01

    Models of network formation emphasize the importance of social similarity and propinquity in producing strong interpersonal connections. The positive effect each factor can have on tie strength has been documented across a number of studies, and yet we know surprisingly very little about how the two factors combine to produce strong ties. Being in close proximity could either amplify or dampen the positive effect that social similarity can have on tie strength. Data on tie strength among teac...

  17. 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. 

  18. Large photonic band gaps and strong attenuations of two-segment-connected Peano derivative networks

    International Nuclear Information System (INIS)

    Lu, Jian; Yang, Xiangbo; Zhang, Guogang; Cai, Lianzhang

    2011-01-01

    In this Letter, based on ancient Peano curves we construct four kinds of interesting Peano derivative networks composed of one-dimensional (1D) waveguides and investigate the optical transmission spectra and photonic attenuation behavior of electromagnetic (EM) waves in one- and two-segment-connected networks. It is found that for some two-segment-connected networks large photonic band gaps (PBGs) can be created and the widths of large PBGs can be controlled by adjusting the matching ratio of waveguide length and are insensitive to generation number. Diamond- and hexagon-Peano networks are good selectable structures for the designing of optical devices with large PBG(s) and strong attenuation(s). -- Highlights: → Peano and Peano derivative networks composed of 1D waveguides are designed. → Large PBGs with strong attenuations have been created by these fractal networks. → New approach for designing optical devices with large PBGs is proposed. → Diamond- and hexagon-Peano networks with d2:d1=2:1 are good selectable structures.

  19. Topological networks for quantum communication between distant qubits

    Science.gov (United States)

    Lang, Nicolai; Büchler, Hans Peter

    2017-11-01

    Efficient communication between qubits relies on robust networks, which allow for fast and coherent transfer of quantum information. It seems natural to harvest the remarkable properties of systems characterized by topological invariants to perform this task. Here, we show that a linear network of coupled bosonic degrees of freedom, characterized by topological bands, can be employed for the efficient exchange of quantum information over large distances. Important features of our setup are that it is robust against quenched disorder, all relevant operations can be performed by global variations of parameters, and the time required for communication between distant qubits approaches linear scaling with their distance. We demonstrate that our concept can be extended to an ensemble of qubits embedded in a two-dimensional network to allow for communication between all of them.

  20. Silicon-based optical integrated circuits for terabit communication networks

    International Nuclear Information System (INIS)

    Svidzinsky, K K

    2003-01-01

    A brief review is presented of the development of silicon-based optical integrated circuits used as components in modern all-optical communication networks with the terabit-per-second transmission capacity. The designs and technologies for manufacturing these circuits are described and the problems related to their development and application in WDM communication systems are considered. (special issue devoted to the memory of academician a m prokhorov)

  1. Wireless ad hoc networks access for aeronautical communications

    OpenAIRE

    Besse , Frédéric; Garcia , Fabien; Pirovano , Alain; Radzik , José

    2010-01-01

    International audience; There is an increasing interest in the current aeronautical context to offer new services for civil aircraft passengers. For example, airlines want to offer their customers the opportunity to access the Internet, to manage their mails, to watch video on demand, to access corporate VPNs.... All these services represent a new type of air-ground communications called APC (Aeronautical Passenger Communications) in the ATN (Aeronautical Telecommunication Network) context. I...

  2. 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.

  3. 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.

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

    KAUST Repository

    Saeed, Nasir; Celik, Abdulkadir; Al-Naffouri, Tareq Y.; Alouini, Mohamed-Slim

    2018-01-01

    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.

  5. 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.

  6. Dynamic Pathloss Model for Future Mobile Communication Networks

    DEFF Research Database (Denmark)

    Kumar, Ambuj; Mihovska, Albena Dimitrova; Prasad, Ramjee

    2016-01-01

    that are essentially static. Therefore, once the signal level drops beyond the predicted values due to any variance in the environmental conditions, very crowded areas may not be catered well enough by the deployed network that had been designed with the static path loss model. This paper proposes an approach......— Future mobile communication networks (MCNs) are expected to be more intelligent and proactive based on new capabilities that increase agility and performance. However, for any successful mobile network service, the dexterity in network deployment is a key factor. The efficiency of the network...... planning depends on how congruent the chosen path loss model and real propagation are. Various path loss models have been developed that predict the signal propagation in various morphological and climatic environments; however they consider only those physical parameters of the network environment...

  7. 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.

  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. 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...

  10. Reliability of Broadcast Communications Under Sparse Random Linear Network Coding

    OpenAIRE

    Brown, Suzie; Johnson, Oliver; Tassi, Andrea

    2018-01-01

    Ultra-reliable Point-to-Multipoint (PtM) communications are expected to become pivotal in networks offering future dependable services for smart cities. In this regard, sparse Random Linear Network Coding (RLNC) techniques have been widely employed to provide an efficient way to improve the reliability of broadcast and multicast data streams. This paper addresses the pressing concern of providing a tight approximation to the probability of a user recovering a data stream protected by this kin...

  11. 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

  12. Networked Airborne Communications Using Adaptive Multi Beam Directional Links

    Science.gov (United States)

    2016-03-05

    Networked Airborne Communications Using Adaptive Multi-Beam Directional Links R. Bruce MacLeod Member, IEEE, and Adam Margetts Member, IEEE MIT...provide new techniques for increasing throughput in airborne adaptive directional net- works. By adaptive directional linking, we mean systems that can...techniques can dramatically increase the capacity in airborne networks. Advances in digital array technology are beginning to put these gains within reach

  13. A demand assignment control in international business satellite communications network

    Science.gov (United States)

    Nohara, Mitsuo; Takeuchi, Yoshio; Takahata, Fumio; Hirata, Yasuo

    An experimental system is being developed for use in an international business satellite (IBS) communications network based on demand-assignment (DA) and TDMA techniques. This paper discusses its system design, in particular from the viewpoints of a network configuration, a DA control, and a satellite channel-assignment algorithm. A satellite channel configuration is also presented along with a tradeoff study on transmission rate, HPA output power, satellite resource efficiency, service quality, and so on.

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

    African Journals Online (AJOL)

    ES Obe

    work fraud dynamics by network administrators and stakeholders. In considering ... cyber crime within the last two years. How- ever, two-thirds of the ... ˆ increased exposure to unpredictable fi- nancial losses ... The intentions of the customers are reflected ..... 'There is a 95% confidence that the differ- ence between the ...

  15. 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.

  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)

    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 ...

  18. High speed switching for computer and communication networks

    NARCIS (Netherlands)

    Dorren, H.J.S.

    2014-01-01

    The role of data centers and computers are vital for the future of our data-centric society. Historically the performance of data-centers is increasing with a factor 100-1000 every ten years and as a result of this the capacity of the data-center communication network has to scale accordingly. This

  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. Computer-mediated-communication and social networking tools at work

    NARCIS (Netherlands)

    Ou, C.X.J.; Sia, C.L.; Hui, C.K.

    2013-01-01

    Purpose – Advances in information technology (IT) have resulted in the development of various computer‐mediated communication (CMC) and social networking tools. However, quantifying the benefits of utilizing these tools in the organizational context remains a challenge. In this study, the authors

  1. Identifying and Analyzing Strong Components of an Industrial Network Based on Cycle Degree

    Directory of Open Access Journals (Sweden)

    Zhiying Zhang

    2016-01-01

    Full Text Available In the era of big data and cloud computing, data research focuses not only on describing the individual characteristics but also on depicting the relationships among individuals. Studying dependence and constraint relationships among industries has aroused significant interest in the academic field. From the network perspective, this paper tries to analyze industrial relational structures based on cycle degree. The cycle degree of a vertex, that is, the number of cycles through a vertex in an industrial network, can describe the roles of the vertices of strong components in industrial circulation. In most cases, different vertices in a strong component have different cycle degrees, and the one with a larger cycle degree plays more important roles. However, the concept of cycle degree does not involve the lengths of the cycles, which are also important for circulations. The more indirect the relationship between two industries is, the weaker it is. In order to analyze strong components thoroughly, this paper proposes the concept of circular centrality taking into consideration the influence by two factors: the lengths and the numbers of cycles through a vertex. Exemplification indicates that a profound analysis of strong components in an industrial network can reveal the features of an economy.

  2. 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.

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

    Science.gov (United States)

    Chitre, D. M.

    1991-01-01

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

  4. 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.

  5. Network Coding for Hop-by-Hop Communication Enhancement in Multi-hop Networks

    DEFF Research Database (Denmark)

    Pahlevani, Peyman; Khamfroush, Hana; Roetter, Daniel Enrique Lucani

    2016-01-01

    In our recent study, we introduced the PlayNCool protocol that increases the throughput of the wireless networks by enabling a helper node to strengthen the communication link between two neighboring nodes and using random linear network coding. This paper focuses on design and implementation adv...

  6. 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.

  7. Reliability Improved Cooperative Communication over Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Zhuangbin Chen

    2017-10-01

    Full Text Available With the development of smart devices and connection technologies, Wireless Sensor Networks (WSNs are becoming increasingly intelligent. New or special functions can be obtained by receiving new versions of program codes to upgrade their software systems, forming the so-called smart Internet of Things (IoT. Due to the lossy property of wireless channels, data collection in WSNs still suffers from a long delay, high energy consumption, and many retransmissions. Thanks to wireless software-defined networks (WSDNs, software in sensors can now be updated to help them transmit data cooperatively, thereby achieving more reliable communication. In this paper, a Reliability Improved Cooperative Communication (RICC data collection scheme is proposed to improve the reliability of random-network-coding-based cooperative communications in multi-hop relay WSNs without reducing the network lifetime. In WSNs, sensors in different positions can have different numbers of packets to handle, resulting in the unbalanced energy consumption of the network. In particular, nodes in non-hotspot areas have up to 90% of their original energy remaining when the network dies. To efficiently use the residual energy, in RICC, high data transmission power is adopted in non-hotspot areas to achieve a higher reliability at the cost of large energy consumption, and relatively low transmission power is adopted in hotspot areas to maintain the long network lifetime. Therefore, high reliability and a long network lifetime can be obtained simultaneously. The simulation results show that compared with other scheme, RICC can reduce the end-to-end Message Fail delivering Ratio (MFR by 59.4%–62.8% under the same lifetime with a more balanced energy utilization.

  8. 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.

  9. 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.

  10. 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.

  11. 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...

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. Joint Preprocesser-Based Detectors for One-Way and Two-Way Cooperative Communication Networks

    KAUST Repository

    Abuzaid, Abdulrahman I.

    2014-01-01

    Efficient receiver designs for cooperative communication networks are becoming increasingly important. In previous work, cooperative networks communicated with the use of L relays. As the receiver is constrained, channel shortening and reduced

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

    KAUST Repository

    Haskovec, Jan

    2014-01-01

    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

  18. Multilevel Approximations of Markovian Jump Processes with Applications in Communication Networks

    KAUST Repository

    Vilanova, Pedro

    2015-01-01

    for modeling networks of smart devices —tiny, abundant microprocessors with integrated sensors and wireless communication abilities— that form highly complex and diverse communication networks. During 2010, the number of devices connected to the Internet

  19. 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)

  20. 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.

  1. 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.

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

    Directory of Open Access Journals (Sweden)

    O. Simeone

    2007-03-01

    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.

  3. 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

  4. 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...

  5. Verbal working memory-related neural network communication in schizophrenia.

    Science.gov (United States)

    Kustermann, Thomas; Popov, Tzvetan; Miller, Gregory A; Rockstroh, Brigitte

    2018-04-19

    Impaired working memory (WM) in schizophrenia is associated with reduced hemodynamic and electromagnetic activity and altered network connectivity within and between memory-associated neural networks. The present study sought to determine whether schizophrenia involves disruption of a frontal-parietal network normally supporting WM and/or involvement of another brain network. Nineteen schizophrenia patients (SZ) and 19 healthy comparison subjects (HC) participated in a cued visual-verbal Sternberg task while dense-array EEG was recorded. A pair of item arrays each consisting of 2-4 consonants was presented bilaterally for 200 ms with a prior cue signaling the hemifield of the task-relevant WM set. A central probe letter 2,000 ms later prompted a choice reaction time decision about match/mismatch with the target WM set. Group and WM load effects on time domain and time-frequency domain 11-15 Hz alpha power were assessed for the cue-to-probe time window, and posterior 11-15 Hz alpha power and frontal 4-8 Hz theta power were assessed during the retention period. Directional connectivity was estimated via Granger causality, evaluating group differences in communication. SZ showed slower responding, lower accuracy, smaller overall time-domain alpha power increase, and less load-dependent alpha power increase. Midline frontal theta power increases did not vary by group or load. Network communication in SZ was characterized by temporal-to-posterior information flow, in contrast to bidirectional temporal-posterior communication in HC. Results indicate aberrant WM network activity supporting WM in SZ that might facilitate normal load-dependent and only marginally less accurate task performance, despite generally slower responding. © 2018 Society for Psychophysiological Research.

  6. 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...

  7. 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. PMID

  8. 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.

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

    Directory of Open Access Journals (Sweden)

    Luke J Matthews

    Full Text Available 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

  10. 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,

  11. 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)

  12. 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

  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. Study on Communication Mode of Wireless Sensor Networks Based on Effective Result

    International Nuclear Information System (INIS)

    Shi, J F; Zhong, X X; Chen, S

    2006-01-01

    The key challenge in wireless sensor networks is maximizing network lifetime. It will significantly reduce energy consumption of communication and prolong networks lifetime to choose appropriate communication mode. In this paper, energy model and communication topology are proposed, and then from the viewpoint of effective result, expression for communication energy cost of single sensor node and overall system in different communication mode is derived, impact that sensor nodes amount, communication radius and propagation loss exponent pose on communication mode based on simulations is analyzed, and the justification for choosing communication mode is summarized

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Modeling and analysis of mobility management in mobile communication networks.

    Science.gov (United States)

    Baek, Woon Min; Yoon, Ji Hyun; Kim, Chesoong

    2014-01-01

    Many strategies have been proposed to reduce the mobility management cost in mobile communication networks. This paper studies the zone-based registration methods that have been adopted by most mobile communication networks. We focus on two special zone-based registration methods, called two-zone registration (2Z) and two-zone registration with implicit registration by outgoing calls (2Zi). We provide a new mathematical model to analyze the exact performance of 2Z and 2Zi. We also present various numerical results, to compare the performance of 2Zi with those of 2Z and one-zone registration (1Z), and show that 2Zi is superior to 2Z as well as 1Z in most cases.

  1. 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

  2. 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.

  3. Expert Game experiment predicts emergence of trust in professional communication networks.

    Science.gov (United States)

    Bendtsen, Kristian Moss; Uekermann, Florian; Haerter, Jan O

    2016-10-25

    Strong social capital is increasingly recognized as an organizational advantage. Better knowledge sharing and reduced transaction costs increase work efficiency. To mimic the formation of the associated communication network, we propose the Expert Game, where each individual must find a specific expert and receive her help. Participants act in an impersonal environment and under time constraints that provide short-term incentives for noncooperative behavior. Despite these constraints, we observe cooperation between individuals and the self-organization of a sustained trust network, which facilitates efficient communication channels with increased information flow. We build a behavioral model that explains the experimental dynamics. Analysis of the model reveals an exploitation protection mechanism and measurable social capital, which quantitatively describe the economic utility of trust.

  4. 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

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

    Science.gov (United States)

    Onnela, Jukka-Pekka; Saramäki, Jari; Hyvönen, Jörkki; Szabó, Gábor; Argollo de Menezes, M.; Kaski, Kimmo; Barabási, Albert-László; Kertész, János

    2007-06-01

    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.

  6. 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.

  7. Information communications technologies that surpass the global communications network. Sekai tsushinmo o koeru joho tsushin gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    1990-05-01

    Development of information communications technologies that surpass the global communications network is being pushed forward in order to establish the global village that McLuhan foretold in 1964. Effects of hybrid intensification with the intensification of communications technologies and computer technologies have become evident as facsimiles, automated teller machines of banks, home videos, automatic response telephones with synthetic voices, compact disks, portable telephones, video games and high-definition televisions were developed and put to use in a wide range. Intensification and integration of computer technologies and communications technologies has every possibility, but it also has a peculiar aspect of lacking guiding principles. Uncertain factors of the values of informations in the market are ever increasing, and their true values are yet to be found. Anyhow, it is a long way to the goal of the global village.

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

    Energy Technology Data Exchange (ETDEWEB)

    Son, Kwang Seop; Lee, Jang Soo; Kim, Jung Heon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2009-05-15

    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.

  9. 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

  10. 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?

  11. 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.

  12. REDISTRIBUTION OF BASE STATIONS LOAD IN MOBILE COMMUNICATION NETWORKS

    Directory of Open Access Journals (Sweden)

    Igor Ruban

    2017-09-01

    Full Text Available The subject matter of the article is the processes of load distribution in mobile communication networks. The object of research is the handover. The goal is to develop a method for redistributing the load between neighboring areas for mobile nodes. The considered base stations are supposed to have the signal-to-noise ratios that are equal or close. The methods that are used: methods of system analysis, methods of digital signal processing. The following results are obtained. The method that allows mobile nodes, whose signal-to-noise ratios are equal or close, to switch to a less loaded base station. This method allows the base station to launch the handover process enabling more even distribution of the load from mobile nodes among neighboring base stations in wireless and mobile networks. In the suggested modification of the method, the function assessing the bandwidth of the uplink channel is added to the base stations, as well a threshold value for using its bandwidth. Thus, when the current value of bandwidth reaches the threshold, the base station starts sending out a message to all mobile nodes and verifies free neighboring areas for switching over mobile nodes. If there are adjacent areas with a lower load, the base station notifies all potential candidates about the necessity of their switching over. The handover process is launched when the available bandwidth of the base station decreases below a certain threshold. Therefore, it is possible to optimize the operation of the WiMAX network with respect to the criterion of the total bandwidth capacity of the base stations. Besides, the results of the comparative analysis of the handover process in networks based on the WiMAX technology that are obtained using the OpNet simulation environment are presented. Conclusions.The suggested approach can be used to improve the basic software of mobile communication networks. When moving a node from one area to another one in access servers, the

  13. Hanford strong motion accelerometer network: A summary of the first months of operation

    International Nuclear Information System (INIS)

    Conrads, T.J.

    1997-01-01

    The Hanford Seismic Monitoring Network consists of two designs of equipment and sites: seismometer sites and strong motion accelerometer (SMA) sites. Seismometer sites are designed to locate earthquakes on and near the Hanford Site and determine their magnitude and hypocenter location. The US Department of Energy (DOE) Order 5480.28, Natural Phenomena Hazards (DOE 1993) requires that facilities or sites that have structures or components in Performance Category 2 with hazardous material, and all Performance Category 3 and 4 facilities shall have instrumentation or other means to detect and record the occurrence and severity of seismic events. In order to comply with DOE Order 5480.28, the Hanford Seismic Monitoring Network seismometer sites needed to be complemented with strong motion accelerometers to record the ground motion at specific sites. The combined seismometer sites and strong motion accelerometer sites provide the Hanford Site with earthquake information to comply with DOE Order 5480.28. The data from these instruments will be used by the PHMC staff to assess the damage to facilities following a significant earthquake

  14. Communication and cooperation in networked environments: an experimental analysis.

    Science.gov (United States)

    Galimberti, C; Ignazi, S; Vercesi, P; Riva, G

    2001-02-01

    Interpersonal communication and cooperation do not happen exclusively face to face. In work contexts, as in private life, there are more and more situations of mediated communication and cooperation in which new online tools are used. However, understanding how to use the Internet to support collaborative interaction presents a substantial challenge for the designers and users of this emerging technology. First, collaborative Internet environments are designed to serve a purpose, so must be designed with intended users' tasks and goals explicitly considered. Second, in cooperative activities the key content of communication is the interpretation of the situations in which actors are involved. So, the most effective way of clarifying the meaning of messages is to connect them to a shared context of meaning. However, this is more difficult in the Internet than in other computer-based activities. This paper tries to understand the characteristics of cooperative activities in networked environments--shared 3D virtual worlds--through two different studies. The first used the analysis of conversations to explore the characteristics of the interaction during the cooperative task; the second analyzed whether and how the level of immersion in the networked environments influenced the performance and the interactional process. The results are analyzed to identify the psychosocial roots used to support cooperation in a digital interactive communication.

  15. 75 FR 26180 - Effects on Broadband Communications Networks of Damage To or Failure of Network Equipment or...

    Science.gov (United States)

    2010-05-11

    ... FEDERAL COMMUNICATIONS COMMISSION 47 CFR Chapter I [PS Docket No. 10-92; FCC 10-62] Effects on... the National Broadband Plan, the Federal Communications Commission (Commission or FCC) adopted this... networks and to explore potential measures to reduce network vulnerability to failures in network equipment...

  16. Theorising big IT programmes in healthcare: strong structuration theory meets actor-network theory.

    Science.gov (United States)

    Greenhalgh, Trisha; Stones, Rob

    2010-05-01

    The UK National Health Service is grappling with various large and controversial IT programmes. We sought to develop a sharper theoretical perspective on the question "What happens - at macro-, meso- and micro-level - when government tries to modernise a health service with the help of big IT?" Using examples from data fragments at the micro-level of clinical work, we considered how structuration theory and actor-network theory (ANT) might be combined to inform empirical investigation. Giddens (1984) argued that social structures and human agency are recursively linked and co-evolve. ANT studies the relationships that link people and technologies in dynamic networks. It considers how discourses become inscribed in data structures and decision models of software, making certain network relations irreversible. Stones' (2005) strong structuration theory (SST) is a refinement of Giddens' work, systematically concerned with empirical research. It views human agents as linked in dynamic networks of position-practices. A quadripartite approcach considers [a] external social structures (conditions for action); [b] internal social structures (agents' capabilities and what they 'know' about the social world); [c] active agency and actions and [d] outcomes as they feed back on the position-practice network. In contrast to early structuration theory and ANT, SST insists on disciplined conceptual methodology and linking this with empirical evidence. In this paper, we adapt SST for the study of technology programmes, integrating elements from material interactionism and ANT. We argue, for example, that the position-practice network can be a socio-technical one in which technologies in conjunction with humans can be studied as 'actants'. Human agents, with their complex socio-cultural frames, are required to instantiate technology in social practices. Structurally relevant properties inscribed and embedded in technological artefacts constrain and enable human agency. The fortunes

  17. 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.

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

    Directory of Open Access Journals (Sweden)

    Nadeem Javaid

    2015-02-01

    Full Text Available 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.

  19. 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

  20. The communications in early warning network for radiation monitoring

    International Nuclear Information System (INIS)

    Oyoun, M.B.; Al-Hussin, Mohamad; Fares, Adnan; Al-Oulabi, Yasser; Othman, Ibrahim

    1992-07-01

    The objectives of early warning network are: The determination of gamma radiation (background) levels in air which depend on location and time, evaluation of any situation resulting from radiation or nuclear accident out of boarder, and after that reporting the emergency situation to relevant authorities on the national and international levels. Monitoring stations were installed using Gm tubes to cover boarder lines from south to north and east to west as follows: Damascus, Darra, Latakia, Tartous, Aleppo, Kamishly, Ragaa, and Qunitra. The following modes of communication: Telephone line, leased line, direct connection, and Syrian data network were used in the Syrian early network. This project was carried out in cooperation with IAEA under project no. RER/9/003. (author). 22 figs., 1 tab

  1. Altered network communication following a neuroprotective drug treatment.

    Directory of Open Access Journals (Sweden)

    Kathleen Vincent

    Full Text Available Preconditioning is defined as a range of stimuli that allow cells to withstand subsequent anaerobic and other deleterious conditions. While cell protection under preconditioning is well established, this paper investigates the influence of neuroprotective preconditioning drugs, 4-aminopyridine and bicuculline (4-AP/bic, on synaptic communication across a broad network of in vitro rat cortical neurons. Using a permutation test, we evaluated cross-correlations of extracellular spiking activity across all pairs of recording electrodes on a 64-channel multielectrode array. The resulting functional connectivity maps were analyzed in terms of their graph-theoretic properties. A small-world effect was found, characterized by a functional network with high clustering coefficient and short average path length. Twenty-four hours after exposure to 4-AP/bic, small-world properties were comparable to control cultures that were not treated with the drug. Four hours following drug washout, however, the density of functional connections increased, while path length decreased and clustering coefficient increased. These alterations in functional connectivity were maintained at four days post-washout, suggesting that 4-AP/bic preconditioning leads to long-term effects on functional networks of cortical neurons. Because of their influence on communication efficiency in neuronal networks, alterations in small-world properties hold implications for information processing in brain systems. The observed relationship between density, path length, and clustering coefficient is captured by a phenomenological model where connections are added randomly within a spatially-embedded network. Taken together, results provide information regarding functional consequences of drug therapies that are overlooked in traditional viability studies and present the first investigation of functional networks under neuroprotective preconditioning.

  2. Strong convective storm nowcasting using a hybrid approach of convolutional neural network and hidden Markov model

    Science.gov (United States)

    Zhang, Wei; Jiang, Ling; Han, Lei

    2018-04-01

    Convective storm nowcasting refers to the prediction of the convective weather initiation, development, and decay in a very short term (typically 0 2 h) .Despite marked progress over the past years, severe convective storm nowcasting still remains a challenge. With the boom of machine learning, it has been well applied in various fields, especially convolutional neural network (CNN). In this paper, we build a servere convective weather nowcasting system based on CNN and hidden Markov model (HMM) using reanalysis meteorological data. The goal of convective storm nowcasting is to predict if there is a convective storm in 30min. In this paper, we compress the VDRAS reanalysis data to low-dimensional data by CNN as the observation vector of HMM, then obtain the development trend of strong convective weather in the form of time series. It shows that, our method can extract robust features without any artificial selection of features, and can capture the development trend of strong convective storm.

  3. 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.

  4. 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

  5. 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.

  6. Place-based attributes predict community membership in a mobile phone communication network.

    Directory of Open Access Journals (Sweden)

    T Trevor Caughlin

    Full Text Available Social networks can be organized into communities of closely connected nodes, a property known as modularity. Because diseases, information, and behaviors spread faster within communities than between communities, understanding modularity has broad implications for public policy, epidemiology and the social sciences. Explanations for community formation in social networks often incorporate the attributes of individual people, such as gender, ethnicity or shared activities. High modularity is also a property of large-scale social networks, where each node represents a population of individuals at a location, such as call flow between mobile phone towers. However, whether or not place-based attributes, including land cover and economic activity, can predict community membership for network nodes in large-scale networks remains unknown. We describe the pattern of modularity in a mobile phone communication network in the Dominican Republic, and use a linear discriminant analysis (LDA to determine whether geographic context can explain community membership. Our results demonstrate that place-based attributes, including sugar cane production, urbanization, distance to the nearest airport, and wealth, correctly predicted community membership for over 70% of mobile phone towers. We observed a strongly positive correlation (r = 0.97 between the modularity score and the predictive ability of the LDA, suggesting that place-based attributes can accurately represent the processes driving modularity. In the absence of social network data, the methods we present can be used to predict community membership over large scales using solely place-based attributes.

  7. Place-based attributes predict community membership in a mobile phone communication network.

    Science.gov (United States)

    Caughlin, T Trevor; Ruktanonchai, Nick; Acevedo, Miguel A; Lopiano, Kenneth K; Prosper, Olivia; Eagle, Nathan; Tatem, Andrew J

    2013-01-01

    Social networks can be organized into communities of closely connected nodes, a property known as modularity. Because diseases, information, and behaviors spread faster within communities than between communities, understanding modularity has broad implications for public policy, epidemiology and the social sciences. Explanations for community formation in social networks often incorporate the attributes of individual people, such as gender, ethnicity or shared activities. High modularity is also a property of large-scale social networks, where each node represents a population of individuals at a location, such as call flow between mobile phone towers. However, whether or not place-based attributes, including land cover and economic activity, can predict community membership for network nodes in large-scale networks remains unknown. We describe the pattern of modularity in a mobile phone communication network in the Dominican Republic, and use a linear discriminant analysis (LDA) to determine whether geographic context can explain community membership. Our results demonstrate that place-based attributes, including sugar cane production, urbanization, distance to the nearest airport, and wealth, correctly predicted community membership for over 70% of mobile phone towers. We observed a strongly positive correlation (r = 0.97) between the modularity score and the predictive ability of the LDA, suggesting that place-based attributes can accurately represent the processes driving modularity. In the absence of social network data, the methods we present can be used to predict community membership over large scales using solely place-based attributes.

  8. 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

  9. 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...

  10. 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.

  11. 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.

  12. AC Electric Field Communication for Human-Area Networking

    Science.gov (United States)

    Kado, Yuichi; Shinagawa, Mitsuru

    We have proposed a human-area networking technology that uses the surface of the human body as a data transmission path and uses an AC electric field signal below the resonant frequency of the human body. This technology aims to achieve a “touch and connect” intuitive form of communication by using the electric field signal that propagates along the surface of the human body, while suppressing both the electric field radiating from the human body and mutual interference. To suppress the radiation field, the frequency of the AC signal that excites the transmitter electrode must be lowered, and the sensitivity of the receiver must be raised while reducing transmission power to its minimally required level. We describe how we are developing AC electric field communication technologies to promote the further evolution of a human-area network in support of ubiquitous services, focusing on three main characteristics, enabling-transceiver technique, application-scenario modeling, and communications quality evaluation. Special attention is paid to the relationship between electro-magnetic compatibility evaluation and regulations for extremely low-power radio stations based on Japan's Radio Law.

  13. Traditional Art in the Age of Multimedia and Network Communications

    Directory of Open Access Journals (Sweden)

    Željko Rutović

    2013-09-01

    Full Text Available The digital age has opened up enormous possibilities of expression, perception and reading of art. Aesthetic criteria immanent to the models of traditional art transforming into a new conceptuality which is in conformity with the techniques of rapid production and distribution. World of multi-network communications and major technological shift resulting in the metamorphosis of the concept and experience of the definition of art. That means that art is outgoing from the traditional framework of standards and ways of expression, ie. aesthetic and values position of the sense of art. Outside the emblematic of the media traditional linear progress, modern network, according to its ontology, deconstructs forced poetics structure formalism, defining the phenomenology innovative problem-solving discourse situated in the self-reflection plurality as a sign of communication currency of man’s perception of (sur real. The multimedia art is in direct way with aesthetic and communication constructs that reformulating the mediating role, it is a dimension of openness and shifting boundaries seen in the image of the antipode of unquestionable durability.

  14. Interplant communication of tomato plants through underground common mycorrhizal networks.

    Science.gov (United States)

    Song, Yuan Yuan; Zeng, Ren Sen; Xu, Jian Feng; Li, Jun; Shen, Xiang; Yihdego, Woldemariam Gebrehiwot

    2010-10-13

    Plants can defend themselves to pathogen and herbivore attack by responding to chemical signals that are emitted by attacked plants. It is well established that such signals can be transferred through the air. In theory, plants can also communicate with each other through underground common mycorrhizal networks (CMNs) that interconnect roots of multiple plants. However, until now research focused on plant-to-plant carbon nutrient movement and there is no evidence that defense signals can be exchanged through such mycorrhizal hyphal networks. Here, we show that CMNs mediate plant-plant communication between healthy plants and pathogen-infected tomato plants (Lycopersicon esculentum Mill.). After establishment of CMNs with the arbuscular mycorrhizal fungus Glomus mosseae between tomato plants, inoculation of 'donor' plants with the pathogen Alternaria solani led to increases in disease resistance and activities of the putative defensive enzymes, peroxidase, polyphenol oxidase, chitinase, β-1,3-glucanase, phenylalanine ammonia-lyase and lipoxygenase in healthy neighbouring 'receiver' plants. The uninfected 'receiver' plants also activated six defence-related genes when CMNs connected 'donor' plants challenged with A. solani. This finding indicates that CMNs may function as a plant-plant underground communication conduit whereby disease resistance and induced defence signals can be transferred between the healthy and pathogen-infected neighbouring plants, suggesting that plants can 'eavesdrop' on defence signals from the pathogen-challenged neighbours through CMNs to activate defences before being attacked themselves.

  15. 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.

  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. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Optimal Time Allocation in Backscatter Assisted Wireless Powered Communication Networks

    Science.gov (United States)

    Lyu, Bin; Yang, Zhen; Gui, Guan; Sari, Hikmet

    2017-01-01

    This paper proposes a wireless powered communication network (WPCN) assisted by backscatter communication (BackCom). This model consists of a power station, an information receiver and multiple users that can work in either BackCom mode or harvest-then-transmit (HTT) mode. The time block is mainly divided into two parts corresponding to the data backscattering and transmission periods, respectively. The users first backscatter data to the information receiver in time division multiple access (TDMA) during the data backscattering period. When one user works in the BackCom mode, the other users harvest energy from the power station. During the data transmission period, two schemes, i.e., non-orthogonal multiple access (NOMA) and TDMA, are considered. To maximize the system throughput, the optimal time allocation policies are obtained. Simulation results demonstrate the superiority of the proposed model. PMID:28587171

  2. 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.

  3. 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.

  4. Quality Utilization Aware Based Data Gathering for Vehicular Communication Networks

    Directory of Open Access Journals (Sweden)

    Yingying Ren

    2018-01-01

    Full Text Available The vehicular communication networks, which can employ mobile, intelligent sensing devices with participatory sensing to gather data, could be an efficient and economical way to build various applications based on big data. However, high quality data gathering for vehicular communication networks which is urgently needed faces a lot of challenges. So, in this paper, a fine-grained data collection framework is proposed to cope with these new challenges. Different from classical data gathering which concentrates on how to collect enough data to satisfy the requirements of applications, a Quality Utilization Aware Data Gathering (QUADG scheme is proposed for vehicular communication networks to collect the most appropriate data and to best satisfy the multidimensional requirements (mainly including data gathering quantity, quality, and cost of application. In QUADG scheme, the data sensing is fine-grained in which the data gathering time and data gathering area are divided into very fine granularity. A metric named “Quality Utilization” (QU is to quantify the ratio of quality of the collected sensing data to the cost of the system. Three data collection algorithms are proposed. The first algorithm is to ensure that the application which has obtained the specified quantity of sensing data can minimize the cost and maximize data quality by maximizing QU. The second algorithm is to ensure that the application which has obtained two requests of application (the quantity and quality of data collection, or the quantity and cost of data collection could maximize the QU. The third algorithm is to ensure that the application which aims to satisfy the requirements of quantity, quality, and cost of collected data simultaneously could maximize the QU. Finally, we compare our proposed scheme with the existing schemes via extensive simulations which well justify the effectiveness of our scheme.

  5. Performance Modeling of Communication Networks with Markov Chains

    CERN Document Server

    Mo, Jeonghoon

    2010-01-01

    This book is an introduction to Markov chain modeling with applications to communication networks. It begins with a general introduction to performance modeling in Chapter 1 where we introduce different performance models. We then introduce basic ideas of Markov chain modeling: Markov property, discrete time Markov chain (DTMe and continuous time Markov chain (CTMe. We also discuss how to find the steady state distributions from these Markov chains and how they can be used to compute the system performance metric. The solution methodologies include a balance equation technique, limiting probab

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 75 FR 49870 - Effects on Broadband Communications Networks of Damage to or Failure of Network Equipment or...

    Science.gov (United States)

    2010-08-16

    ... FEDERAL COMMUNICATIONS COMMISSION 47 CFR Chapter I [PS Docket No. 10-92; DA 10-1357] Effects on Broadband Communications Networks of Damage to or Failure of Network Equipment or Severe Overload AGENCY... with rubber bands or fasteners. Any envelopes must be disposed of before entering the building...

  14. TAM AIRLINES ON TWITTER: COMMUNICATION CHANNEL OR SOCIAL NETWORK?

    Directory of Open Access Journals (Sweden)

    Cynthia Harumy Watanabe Corrêa

    2010-12-01

    Full Text Available The research emphasizes the social appropriation of Information and Communication Technologies by the Brazilian aviation industry, through a case study of communication strategies of TAM on the social networking site Twitter. TAM is a leader in the Brazilian domestic market and gradually conquering its space in Mercosul. This is an exploratory research, based on content analysis of messages sent to the company profile on Twitter, in order to check whether indeed the consolidation of a social network between TAM and its followers. We analyzed all messages posted since July 3, 2009, the date of the first post in the company profile, until the day January 31, 2010. Among the subjects discussed, there was the predominance of information and promotions. The study concludes that, under Twitter, TAM has yet reached a high degree of social interaction with his followers, because the major number of messages is directed to promotional marketing.

  15. 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.

  16. 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.

  17. Communication: A Jastrow factor coupled cluster theory for weak and strong electron correlation

    International Nuclear Information System (INIS)

    Neuscamman, Eric

    2013-01-01

    We present a Jastrow-factor-inspired variant of coupled cluster theory that accurately describes both weak and strong electron correlation. Compatibility with quantum Monte Carlo allows for variational energy evaluations and an antisymmetric geminal power reference, two features not present in traditional coupled cluster that facilitate a nearly exact description of the strong electron correlations in minimal-basis N 2 bond breaking. In double-ζ treatments of the HF and H 2 O bond dissociations, where both weak and strong correlations are important, this polynomial cost method proves more accurate than either traditional coupled cluster or complete active space perturbation theory. These preliminary successes suggest a deep connection between the ways in which cluster operators and Jastrow factors encode correlation

  18. 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.

  19. Myths on Bi-direction Communication of Web 2.0 Based Social Networks: Is Social Network Truly Interactive?

    Science.gov (United States)

    2011-03-10

    more and more social interactions are happening on the on-line. Especially recent uptake of the social network sites (SNSs), such as Facebook (http...Smart phones • Live updates within social networks • Facebook & Twitters Solution: WebMon for Risk Management Need for New WebMon for Social Networks ...Title: Myths on bi-direction communication of Web 2.0 based social networks : Is social network truly interactive

  20. A cross-layer communication framework for wireless networked control systems

    NARCIS (Netherlands)

    Israr, N.; Scanlon, W.G.; Irwin, G.W.

    2009-01-01

    This paper presents a robust, dynamic cross-layer wireless communication architecture for wireless networked control systems. Each layer in the proposed protocol architecture contributes to the overall goal of reliable, energy efficient communication. The protocol stack also features a

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

    DEFF Research Database (Denmark)

    Ingebrigtsen, Trond; Bøhling, Lasse; Schrøder, Thomas

    2012-01-01

    We show that for any liquid or solid with strong correlation between its NVT virial and potential-energy equilibrium fluctuations, the temperature is a product of a function of excess entropy per particle and a function of density, T = f(s)h(ρ). This implies that (1) the system's isomorphs (curve...

  2. Communication: Strong excitonic and vibronic effects determine the optical properties of Li₂O₂

    DEFF Research Database (Denmark)

    García Lastra, Juan Maria; Bass, J. D.; Thygesen, Kristian Sommer

    2011-01-01

    The band structure and optical absorption spectrum of lithium peroxide (Li2O2) is calculated from first-principles using the G0W0 approximation and the Bethe-Salpeter equation, respectively. A strongly localized (Frenkel type) exciton corresponding to the π*→σ* transition on the O2 −2 peroxide ion...

  3. 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...

  4. Detailed temporal structure of communication networks in groups of songbirds.

    Science.gov (United States)

    Stowell, Dan; Gill, Lisa; Clayton, David

    2016-06-01

    Animals in groups often exchange calls, in patterns whose temporal structure may be influenced by contextual factors such as physical location and the social network structure of the group. We introduce a model-based analysis for temporal patterns of animal call timing, originally developed for networks of firing neurons. This has advantages over cross-correlation analysis in that it can correctly handle common-cause confounds and provides a generative model of call patterns with explicit parameters for the influences between individuals. It also has advantages over standard Markovian analysis in that it incorporates detailed temporal interactions which affect timing as well as sequencing of calls. Further, a fitted model can be used to generate novel synthetic call sequences. We apply the method to calls recorded from groups of domesticated zebra finch (Taeniopygia guttata) individuals. We find that the communication network in these groups has stable structure that persists from one day to the next, and that 'kernels' reflecting the temporal range of influence have a characteristic structure for a calling individual's effect on itself, its partner and on others in the group. We further find characteristic patterns of influences by call type as well as by individual. © 2016 The Authors.

  5. 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.

  6. Design and analysis of communication protocols for quantum repeater networks

    International Nuclear Information System (INIS)

    Jones, Cody; Kim, Danny; Rakher, Matthew T; Ladd, Thaddeus D; Kwiat, Paul G

    2016-01-01

    We analyze how the performance of a quantum-repeater network depends on the protocol employed to distribute entanglement, and we find that the choice of repeater-to-repeater link protocol has a profound impact on entanglement-distribution rate as a function of hardware parameters. We develop numerical simulations of quantum networks using different protocols, where the repeater hardware is modeled in terms of key performance parameters, such as photon generation rate and collection efficiency. These parameters are motivated by recent experimental demonstrations in quantum dots, trapped ions, and nitrogen-vacancy centers in diamond. We find that a quantum-dot repeater with the newest protocol (‘MidpointSource’) delivers the highest entanglement-distribution rate for typical cases where there is low probability of establishing entanglement per transmission, and in some cases the rate is orders of magnitude higher than other schemes. Our simulation tools can be used to evaluate communication protocols as part of designing a large-scale quantum network. (paper)

  7. Cross-Layer Design for Energy-Efficient Secure Multicast Communications in Ad Hoc Networks

    National Research Council Canada - National Science Library

    Lazos, Loukas; Poovendran, Radha

    2004-01-01

    .... They present an analytical formulation of the energy expenditure associated with the communication overhead of key management, and highlight its dependence on network topology and key distribution method...

  8. Fighting A Strong Headwind: Challenges in Communicating The Science of Climate Change

    Science.gov (United States)

    Mann, M. E.

    2008-12-01

    Communicating science to the public is an intrinsic challenge to begin with. An effective communicator must find ways to translate often technical and complex scientific findings for consumption by an audience unfamiliar with the basic tools and lexicon that scientists themselves take for granted. The challenge is made all the more difficult still when the science has implications for public policy, and the scientists face attack by institutions who judge themselves to be at threat by the implications of scientific findings. Such areas of science include (but certainly are not limited to) evolution, stem cell research, environmental health, and the subject of this talk--climate change. In each of these areas, a highly organized, well funded effort has been mounted to attack the science and the scientists themselves. These attacks are rarely fought in legitimate scientific circles such as the peer-reviewed scientific literature or other scholarly venues, but rather through rhetorically-aimed efforts delivered by media outlets aligned with the views of the attackers, and by politicians and groups closely aligned with special interests. I will discuss various approaches to combating such attacks, drawing upon my own experiences in the public arena with regard to the scientific discourse on climate change.

  9. 78 FR 69018 - Improving the Resiliency of Mobile Wireless Communications Networks; Reliability and Continuity...

    Science.gov (United States)

    2013-11-18

    ... consumers value overall network reliability and quality in selecting mobile wireless service providers, they...-125] Improving the Resiliency of Mobile Wireless Communications Networks; Reliability and Continuity... (Reliability NOI) in 2011 to ``initiate a comprehensive examination of issues regarding the reliability...

  10. 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.

  11. 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 ...

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

    Science.gov (United States)

    David, N.; Alpert, P.; Messer, H.

    2009-04-01

    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 (RMSD) were 1.8 g/m3 and 3.4 g/m3 for

  13. Novel method for water vapour monitoring using wireless communication networks measurements

    Science.gov (United States)

    David, N.; Alpert, P.; Messer, H.

    2010-09-01

    We propose a new technique 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 microwave links used in a backhaul cellular network that show very good correlation with surface station humidity measurements (comparisons were performed for several links, found at different locations, during different time periods, showing correlations in the range of 0.5-0.9).

  14. A mars communication constellation for human exploration and network science

    Science.gov (United States)

    Castellini, Francesco; Simonetto, Andrea; Martini, Roberto; Lavagna, Michèle

    2010-01-01

    This paper analyses the possibility of exploiting a small spacecrafts constellation around Mars to ensure a complete and continuous coverage of the planet, for the purpose of supporting future human and robotic operations and taking advantage of optical transmission techniques. The study foresees such a communications mission to be implemented at least after 2020 and a high data-rate requirement is imposed for the return of huge scientific data from massive robotic exploration or to allow video transmissions from a possible human outpost. 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 a feasibility study performed for the primary communications mission. Results are presented for the system trade-offs, including communication architecture, constellation configuration and transfer strategy, and the mission analysis optimization, performed through the application of a multi-objective genetic algorithm to two models of increasing difficulty for the low-thrust trajectory definition. The resulting communication architecture is quite complex and includes six 530 kg 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 lower mass and power consumption with respect to traditional radio-frequency technology, while inter-satellite links and spacecrafts-to-Mars connections are ensured by radio transmissions. The resulting data-rates for Earth-Mars uplink and downlink, satellite-to-satellite and satellite-to-surface are respectively 13.7 Mbps, 10.2 Mbps, 4.8 Mbps and 4.3 Mbps, in worst-case. Two electric propulsion modules are foreseen, to be placed on a C3˜0 escape orbit with two

  15. 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.

  16. 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

  17. DOE waste information network: Data management and communications

    International Nuclear Information System (INIS)

    Fore, C.S.

    1986-01-01

    The U.S. Department of Energy's Waste Information Network (WIN) is an integral part of DOE's Hazardous Waste Remedial Actions Program. WIN has played an active role in the national program's mission to identify the magnitude and nature of existing DOE hazardous chemical and mixed radioactive waste streams and inventories and to provide a mechanism for disseminating pertinent information on technology activities. The information systems activity is structured into three key areas: data base development, data analysis, and data dissemination. As a result of this effort, several key data bases have been developed. Data dissemination is important to the use and management of the diversity of information and communication features developed by the program

  18. Capacity gain with an alternative LTE railway communication network

    DEFF Research Database (Denmark)

    Sniady, Aleksander; Soler, José

    2014-01-01

    , such as 3GPP Long Term Evolution (LTE). T his paper describe s how to adapt the reversible multi - chain/channel queuing system to model an LTE cell serving ETCS - equipped trains . It is proposed to use the multiple user chains available in the model to represent varying bitrate in LTE radio access network....... Usin g this model , LTE and GSM - R are compare d in terms of capacity on an example at Copenhagen Main Train Station . The purpose of this work is to demonstrate the benefits that railway operators and infrastructure managers can expect from the introduc tion of LTE , as a telecommunication technology...... Control System (ETCS) signaling , the capacity of GSM - R turns out to be insufficient . GSM - R cannot ful fill the railway requirements , in terms of the number of simultaneous ETCS connections . This is why , alternative , more efficient communication technologies should be considered by railways...

  19. Energy Harvesting in Heterogeneous Networks with Hybrid Powered Communication Systems

    KAUST Repository

    Alsharoa, Ahmad

    2018-02-12

    In this paper, we investigate an energy efficient and energy harvesting (EH) system model in heterogeneous networks (HetNets) where all base stations (BSS) are equipped to harvest energy from renewable energy sources. We consider a hybrid power supply of green (renewable) and traditional micro-grid, such that traditional micro-grid is not exploited as long as the BSS can meet their power demands from harvested and stored green energy. Therefore, our goal is to minimize the networkwide energy consumption subject to users\\' certain quality of service and BSS\\' power consumption constraints. As a result of binary BS sleeping status and user-cell association variables, proposed is formulated as a binary linear programming (BLP) problem. A green communication algorithm based on binary particle swarm optimization is implemented to solve the problem with low complexity time.

  20. Increasing capacity of baseband digital data communication networks

    Science.gov (United States)

    Frankel, Robert S.; Herman, Alexander

    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.

  1. Increasing capacity of baseband digital data communication networks

    International Nuclear Information System (INIS)

    Frankel, R. S.; Herman, A.

    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

  2. Flash floods warning technique based on wireless communication networks data

    Science.gov (United States)

    David, Noam; Alpert, Pinhas; Messer, Hagit

    2010-05-01

    Flash floods can occur throughout or subsequent to rainfall events, particularly in cases where the precipitation is of high-intensity. Unfortunately, each year these floods cause severe property damage and heavy casualties. At present, there are no sufficient real time flash flood warning facilities found to cope with this phenomenon. Here we show the tremendous potential of flash floods advanced warning based on precipitation measurements of commercial microwave links. As was recently shown, wireless communication networks supply high resolution precipitation measurements at ground level while often being situated in flood prone areas, covering large parts of these hazardous regions. We present the flash flood warning potential of the wireless communication system for two different cases when floods occurred at the Judean desert and at the northern Negev in Israel. In both cases, an advanced warning regarding the hazard could have been announced based on this system. • This research was supported by THE ISRAEL SCIENCE FOUNDATION (grant No. 173/08). This work was also supported by a grant from the Yeshaya Horowitz Association, Jerusalem. Additional support was given by the PROCEMA-BMBF project and by the GLOWA-JR BMBF project.

  3. 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.

  4. 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.

  5. Strong-motion observations of the M 7.8 Gorkha, Nepal, earthquake sequence and development of the N-shake strong-motion network

    Science.gov (United States)

    Dixit, Amod; Ringler, Adam; Sumy, Danielle F.; Cochran, Elizabeth S.; Hough, Susan E.; Martin, Stacey; Gibbons, Steven; Luetgert, James H.; Galetzka, John; Shrestha, Surya; Rajaure, Sudhir; McNamara, Daniel E.

    2015-01-01

    We present and describe strong-motion data observations from the 2015 M 7.8 Gorkha, Nepal, earthquake sequence collected using existing and new Quake-Catcher Network (QCN) and U.S. Geological Survey NetQuakes sensors located in the Kathmandu Valley. A comparison of QCN data with waveforms recorded by a conventional strong-motion (NetQuakes) instrument validates the QCN data. We present preliminary analysis of spectral accelerations, and peak ground acceleration and velocity for earthquakes up to M 7.3 from the QCN stations, as well as preliminary analysis of the mainshock recording from the NetQuakes station. We show that mainshock peak accelerations were lower than expected and conclude the Kathmandu Valley experienced a pervasively nonlinear response during the mainshock. Phase picks from the QCN and NetQuakes data are also used to improve aftershock locations. This study confirms the utility of QCN instruments to contribute to ground-motion investigations and aftershock response in regions where conventional instrumentation and open-access seismic data are limited. Initial pilot installations of QCN instruments in 2014 are now being expanded to create the Nepal–Shaking Hazard Assessment for Kathmandu and its Environment (N-SHAKE) network.

  6. Network embeddedness and organizational performance. The strength of strong ties in Dutch higher education

    NARCIS (Netherlands)

    Schalk, J.; Torenvlied, R.; Allen, J.P.

    2010-01-01

    With only few exceptions, current research in public management on the effects of inter-organizational networks on organizational performance focuses either on network activity or on the inter-organizational network structure. The present paper theoretically links both approaches and tests two

  7. 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

  8. 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…

  9. 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.

  10. 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.

  11. A new way to improve the robustness of complex communication networks by allocating redundancy links

    International Nuclear Information System (INIS)

    Shi Chunhui; Zhuo Yue; Tang Jieying; Long Keping; Peng Yunfeng

    2012-01-01

    We investigate the robustness of complex communication networks on allocating redundancy links. The protecting key nodes (PKN) strategy is proposed to improve the robustness of complex communication networks against intentional attack. Our numerical simulations show that allocating a few redundant links among key nodes using the PKN strategy will significantly increase the robustness of scale-free complex networks. We have also theoretically proved and demonstrated the effectiveness of the PKN strategy. We expect that our work will help achieve a better understanding of communication networks. (paper)

  12. 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…

  13. 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

  14. 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.

  15. 'The Tsukuba Network' as a new medium for promoting research communications in Tsukuba

    Science.gov (United States)

    Taguchi, Masamichi

    The Science and Technology Agency constructed a PC-based communication network system named 'The Tsukuba Network' as a new medium for promoting the research communication in, and with, the Tsukuba City. For about a year prior to full operation, a pilot system was operated with the cooperation of some monitoring users to gain skill and experience for managing the PC-based communication network. The main service functions of the system are : bulletin board service; electronic mail ; construction of, and access to, the databases involving research information in Tsukuba City ; electronic conference; common use of softwares ; connection to other communication networks ( e.g., university and local network). The host computer is a work station EWS4800 and the network processor is a personal computer PC-9801 . These two computers are connected with LAN.

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

    OpenAIRE

    Pirnejad, Habibollah; Bal, Roland; Stoop, Arjen P.; Berg, Marc

    2007-01-01

    Background: 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) has much potential to facilitate the development of such a communication network. Moreover, in order to offer integrated care interoperability of healthcare organizations based upon the exchanged data is of c...

  17. Heterogeneous Networks for the IoT and Machine Type Communications

    OpenAIRE

    Abrignani, Melchiorre Danilo

    2016-01-01

    The Internet of Things promises to be a key-factor in the forthcoming industrial and social revolution. The Internet of Things concept rely on pervasive communications where ’things’ are ’always connected’. The focus of the thesis is on Heterogeneous Networks for Internet of Things and Machine Type Communications. Heterogeneous Networks are an enabling factor of paramount important in order to achieve the ’always connected’ paradigm. On the other hand, Machine Type Communications are deeply d...

  18. 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

  19. 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%.

  20. 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.

  1. 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.

  2. 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.

  3. Evaluation and Simulation of Common Video Conference Traffics in Communication Networks

    Directory of Open Access Journals (Sweden)

    Farhad faghani

    2014-01-01

    Full Text Available Multimedia traffics are the basic traffics in data communication networks. Especially Video conferences are the most desirable traffics in huge networks(wired, wireless, …. Traffic modeling can help us to evaluate the real networks. So, in order to have good services in data communication networks which provide multimedia services, QoS will be very important .In this research we tried to have an exact traffic model design and simulation to overcome QoS challenges. Also, we predict bandwidth by Kalman filter in Ethernet networks.

  4. Implementability of two-qubit unitary operations over the butterfly network and the ladder network with free classical communication

    Energy Technology Data Exchange (ETDEWEB)

    Akibue, Seiseki [Department of Physics, Graduate School of Science, The University of Tokyo, Tokyo (Japan); Murao, Mio [Department of Physics, Graduate School of Science, The University of Tokyo, Tokyo, Japan and NanoQuine, The University of Tokyo, Tokyo (Japan)

    2014-12-04

    We investigate distributed implementation of two-qubit unitary operations over two primitive networks, the butterfly network and the ladder network, as a first step to apply network coding for quantum computation. By classifying two-qubit unitary operations in terms of the Kraus-Cirac number, the number of non-zero parameters describing the global part of two-qubit unitary operations, we analyze which class of two-qubit unitary operations is implementable over these networks with free classical communication. For the butterfly network, we show that two classes of two-qubit unitary operations, which contain all Clifford, controlled-unitary and matchgate operations, are implementable over the network. For the ladder network, we show that two-qubit unitary operations are implementable over the network if and only if their Kraus-Cirac number do not exceed the number of the bridges of the ladder.

  5. Implementability of two-qubit unitary operations over the butterfly network and the ladder network with free classical communication

    International Nuclear Information System (INIS)

    Akibue, Seiseki; Murao, Mio

    2014-01-01

    We investigate distributed implementation of two-qubit unitary operations over two primitive networks, the butterfly network and the ladder network, as a first step to apply network coding for quantum computation. By classifying two-qubit unitary operations in terms of the Kraus-Cirac number, the number of non-zero parameters describing the global part of two-qubit unitary operations, we analyze which class of two-qubit unitary operations is implementable over these networks with free classical communication. For the butterfly network, we show that two classes of two-qubit unitary operations, which contain all Clifford, controlled-unitary and matchgate operations, are implementable over the network. For the ladder network, we show that two-qubit unitary operations are implementable over the network if and only if their Kraus-Cirac number do not exceed the number of the bridges of the ladder

  6. 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,…

  7. 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...

  8. 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...

  9. Delay reduction in multi-hop device-to-device communication using network coding

    KAUST Repository

    Douik, Ahmed S.; Sorour, Sameh; Al-Naffouri, Tareq Y.; Yang, Hong-Chuan; Alouini, Mohamed-Slim

    2015-01-01

    This paper considers the problem of reducing the broadcast delay of wireless networks using instantly decodable network coding (IDNC) based device-to-device (D2D) communications. In D2D-enabled networks, devices help hasten the recovery of the lost

  10. Study on networking issues of medium earth orbit satellite communications systems

    Science.gov (United States)

    Araki, Noriyuki; Shinonaga, Hideyuki; Ito, Yasuhiko

    1993-01-01

    Two networking issues of communications systems with medium earth orbit (MEO) satellites, namely network architectures and location determination and registration methods for hand-held terminals, are investigated in this paper. For network architecture, five candidate architectures are considered and evaluated in terms of signaling traffic. For location determination and registration, two methods are discussed and evaluated.

  11. Coping with the Upcoming Heterogeneity in 5G Communications and Storage Using Fulcrum Network Codes

    DEFF Research Database (Denmark)

    Roetter, Daniel Enrique Lucani; Pedersen, Morten Videbæk; Heide, Janus

    2014-01-01

    In this paper, Fulcrum network codes are introduced as a viable solution to cope with the heterogeneity of 5G communication and storage systems. Fulcrum network codes are an enhancement of random linear network codes (RLNC) offering high throughput performance at low overhead. This contrasts with...

  12. 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.

  13. Computation and Communication Evaluation of an Authentication Mechanism for Time-Triggered Networked Control Systems

    Science.gov (United States)

    Martins, Goncalo; Moondra, Arul; Dubey, Abhishek; Bhattacharjee, Anirban; Koutsoukos, Xenofon D.

    2016-01-01

    In modern networked control applications, confidentiality and integrity are important features to address in order to prevent against attacks. Moreover, network control systems are a fundamental part of the communication components of current cyber-physical systems (e.g., automotive communications). Many networked control systems employ Time-Triggered (TT) architectures that provide mechanisms enabling the exchange of precise and synchronous messages. TT systems have computation and communication constraints, and with the aim to enable secure communications in the network, it is important to evaluate the computational and communication overhead of implementing secure communication mechanisms. This paper presents a comprehensive analysis and evaluation of the effects of adding a Hash-based Message Authentication (HMAC) to TT networked control systems. The contributions of the paper include (1) the analysis and experimental validation of the communication overhead, as well as a scalability analysis that utilizes the experimental result for both wired and wireless platforms and (2) an experimental evaluation of the computational overhead of HMAC based on a kernel-level Linux implementation. An automotive application is used as an example, and the results show that it is feasible to implement a secure communication mechanism without interfering with the existing automotive controller execution times. The methods and results of the paper can be used for evaluating the performance impact of security mechanisms and, thus, for the design of secure wired and wireless TT networked control systems. PMID:27463718

  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. Installation of a digital, wireless, strong-motion network for monitoring seismic activity in a western Colorado coal mining region

    Energy Technology Data Exchange (ETDEWEB)

    Peter Swanson; Collin Stewart; Wendell Koontz [NIOSH, Spokane, WA (USA). Spokane Research Laboratory

    2007-01-15

    A seismic monitoring network has recently been installed in the North Fork Valley coal mining region of western Colorado as part of a NIOSH mine safety technology transfer project with two longwall coal mine operators. Data recorded with this network will be used to characterize mining related and natural seismic activity in the vicinity of the mines and examine potential hazards due to ground shaking near critical structures such as impoundment dams, reservoirs, and steep slopes. Ten triaxial strong-motion accelerometers have been installed on the surface to form the core of a network that covers approximately 250 square kilometers (100 sq. miles) of rugged canyon-mesa terrain. Spread-spectrum radio networks are used to telemeter continuous streams of seismic waveform data to a central location where they are converted to IP data streams and ported to the Internet for processing, archiving, and analysis. 4 refs.

  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. 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.

  20. Let the Weakest Link Go! Empirical Explorations on the Relative Importance of Weak and Strong Ties on Social Networking Sites

    Directory of Open Access Journals (Sweden)

    Nicole C. Krämer

    2014-12-01

    Full Text Available Theoretical approaches as well as empirical results in the area of social capital accumulation on social networking sites suggest that weak ties/bridging versus strong ties/bonding social capital should be distinguished and that while bonding social capital is connected to emotional support, bridging social capital entails the provision of information. Additionally, recent studies imply the notion that weak ties/bridging social capital are gaining increasing importance in today’s social media environments. By means of a survey (N = 317 we challenged these presuppositions by assessing the social support functions that are ascribed to three different types of contacts from participants’ network (weak, medium, or strong tie. In contrast to theoretical assumptions, we do not find that weak ties are experienced to supply informational support whereas strong ties first and foremost provide emotional support. Instead we find that within social networking sites, strong ties are perceived to provide both emotional and informational support and weak ties are perceived as less important than recent literature assumes.

  1. 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.

  2. 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...... to continuously associate (i.e. perform handshake) with the trackside Wi-Fi Access Points (AP) as it moves, which incurs communication delays. Additionally, these APs are connected to the wayside infrastructure via optical fiber cables that incurs huge costs. This paper presents a novel design in which trackside...

  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. Social networking sites: a novel portal for communication.

    Science.gov (United States)

    Farmer, A D; Bruckner Holt, C E M; Cook, M J; Hearing, S D

    2009-09-01

    The internet has transformed many spheres of society. Most notably the advent of social networking websites, such as MySpace, Bebo and Facebook, have attracted many millions of users worldwide. There are over 350 such sites in operation across the internet. There is a paucity of data in the adult literature examining the medical usage of this interesting facet of modern life. To ascertain whether Facebook has user groups that are connected with common medical conditions, and to classify the user groups that were identified as well as enumerating the number of individual users contained therein. We conducted a search of the entire Facebook website between December 2007 and January 2009. We used medical and lay nomenclature for the most prevalent non-communicable diseases as identified from the World Health Organisation Burden of Disease publication to identify whether they were represented among individual Facebook users and user groups. We identified 290,962 individual users who were part of 757 groups. Patient groups accounted for 47.4%, patient/carer support groups 28.1%, fund raising groups 18.6%, and others 5.8%. Notably, there were other groups containing representations from the scientific research community in addition to educational resources. The groups with the most individual members pertained to malignant neoplasms and cardiovascular disease (141,458 users) consistent with their worldwide prevalence. Facebook is providing a readily accessible portal for patients, carers and healthcare professionals to share their experiences of investigation, diagnosis and management of disease. Furthermore, this technology is being used for research, education and fundraising. Further research is warranted to explore the further potential of this new technology.

  8. 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.

  9. Research on the Architecture of a Basic Reconfigurable Information Communication Network

    Directory of Open Access Journals (Sweden)

    Ruimin Wang

    2013-01-01

    Full Text Available The current information network cannot fundamentally meet some urgent requirements, such as providing ubiquitous information services and various types of heterogeneous network, supporting diverse and comprehensive network services, possessing high quality communication effects, ensuring the security and credibility of information interaction, and implementing effective supervisory control. This paper provides the theory system for the basic reconfigurable information communication network based on the analysis of present problems on the Internet and summarizes the root of these problems. It also provides an in-depth discussion about the related technologies and the prime components of the architecture.

  10. 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.

  11. Communication efficiency and congestion of signal traffic in large-scale brain networks.

    Science.gov (United States)

    Mišić, Bratislav; Sporns, Olaf; McIntosh, Anthony R

    2014-01-01

    The complex connectivity of the cerebral cortex suggests that inter-regional communication is a primary function. Using computational modeling, we show that anatomical connectivity may be a major determinant for global information flow in brain networks. A macaque brain network was implemented as a communication network in which signal units flowed between grey matter nodes along white matter paths. Compared to degree-matched surrogate networks, information flow on the macaque brain network was characterized by higher loss rates, faster transit times and lower throughput, suggesting that neural connectivity may be optimized for speed rather than fidelity. Much of global communication was mediated by a "rich club" of hub regions: a sub-graph comprised of high-degree nodes that are more densely interconnected with each other than predicted by chance. First, macaque communication patterns most closely resembled those observed for a synthetic rich club network, but were less similar to those seen in a synthetic small world network, suggesting that the former is a more fundamental feature of brain network topology. Second, rich club regions attracted the most signal traffic and likewise, connections between rich club regions carried more traffic than connections between non-rich club regions. Third, a number of rich club regions were significantly under-congested, suggesting that macaque connectivity actively shapes information flow, funneling traffic towards some nodes and away from others. Together, our results indicate a critical role of the rich club of hub nodes in dynamic aspects of global brain communication.

  12. 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

    ... through a network of cluster trees, where a spanning tree joins groups of fully connected nodes. Through numerical analysis and simulations in GloMoSim, we show throughput, goodput, and loss rates for reliable and unreliable networks...

  13. 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...

  14. SPEED: A Stateless Protocol for Real-Time Communication in Sensor Networks

    National Research Council Canada - National Science Library

    He, Tian; Stankovic, John A; Lu, Chenyang; Abdelzaher, Tarek

    2003-01-01

    .... End-to-end soft real-time communication is achieved by maintaining a desired delivery speed across the sensor network through a novel combination of feedback control and non-deterministic geographic forwarding...

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

    Science.gov (United States)

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

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

  16. Research on TCP/IP network communication based on Node.js

    Science.gov (United States)

    Huang, Jing; Cai, Lixiong

    2018-04-01

    In the face of big data, long connection and high synchronization, TCP/IP network communication will cause performance bottlenecks due to its blocking multi-threading service model. This paper presents a method of TCP/IP network communication protocol based on Node.js. On the basis of analyzing the characteristics of Node.js architecture and asynchronous non-blocking I/O model, the principle of its efficiency is discussed, and then compare and analyze the network communication model of TCP/IP protocol to expound the reasons why TCP/IP protocol stack is widely used in network communication. Finally, according to the large data and high concurrency in the large-scale grape growing environment monitoring process, a TCP server design based on Node.js is completed. The results show that the example runs stably and efficiently.

  17. 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.

  18. 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...

  19. 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,...

  20. Network design consideration of a satellite-based mobile communications system

    Science.gov (United States)

    Yan, T.-Y.

    1986-01-01

    Technical considerations for the Mobile Satellite Experiment (MSAT-X), the ground segment testbed for the low-cost spectral efficient satellite-based mobile communications technologies being developed for the 1990's, are discussed. The Network Management Center contains a flexible resource sharing algorithm, the Demand Assigned Multiple Access scheme, which partitions the satellite transponder bandwidth among voice, data, and request channels. Satellite use of multiple UHF beams permits frequency reuse. The backhaul communications and the Telemetry, Tracking and Control traffic are provided through a single full-coverage SHF beam. Mobile Terminals communicate with the satellite using UHF. All communications including SHF-SHF between Base Stations and/or Gateways, are routed through the satellite. Because MSAT-X is an experimental network, higher level network protocols (which are service-specific) will be developed only to test the operation of the lowest three levels, the physical, data link, and network layers.

  1. Stand-alone solutions, computer networks and extern communications

    International Nuclear Information System (INIS)

    Tarschisch, H.

    1988-01-01

    The advantages of local networks over stand-alone solutions are presented. Of the local networks (LAN), two are presently at the center of attention: the bus and the ring. ETHERNET and the IBM-Token-Ring are described as typical examples. Access to public networks, especially TELEPAC and ISDN, is discussed. 12 figs

  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. 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.

  4. 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...

  5. Let the Weakest Link Go! Empirical Explorations on the Relative Importance of Weak and Strong Ties on Social Networking Sites

    OpenAIRE

    Nicole C. Krämer; Leonie Rösner; Sabrina C. Eimler; Stephan Winter; German Neubaum

    2014-01-01

    Theoretical approaches as well as empirical results in the area of social capital accumulation on social networking sites suggest that weak ties/bridging versus strong ties/bonding social capital should be distinguished and that while bonding social capital is connected to emotional support, bridging social capital entails the provision of information. Additionally, recent studies imply the notion that weak ties/bridging social capital are gaining increasing importance in today’s social media...

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

    OpenAIRE

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

    2014-01-01

    Big data open up unprecedented opportunities to investigate complex systems including the 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 ...

  7. 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.

  8. Effect of correlating adjacent neurons for identifying communications: Feasibility experiment in a cultured neuronal network

    OpenAIRE

    Yoshi Nishitani; Chie Hosokawa; Yuko Mizuno-Matsumoto; Tomomitsu Miyoshi; Shinichi Tamura

    2017-01-01

    Neuronal networks have fluctuating characteristics, unlike the stable characteristics seen in computers. The underlying mechanisms that drive reliable communication among neuronal networks and their ability to perform intelligible tasks remain unknown. Recently, in an attempt to resolve this issue, we showed that stimulated neurons communicate via spikes that propagate temporally, in the form of spike trains. We named this phenomenon “spike wave propagation”. In these previous studies, using ...

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

    Science.gov (United States)

    2017-03-01

    Interface Processor BCT Brigade Combat Team BFT Blue Force Tracking BLOS Beyond Line-of-Sight C2 Command And Control C2E Communications in...Satellite Communications and Tactical Networking Appendix D-2 GIG Global Information Grid GMR Ground Mobile Radio GPS Global Positioning System...System SIPRNet Secret Internet Protocol Router Network SITREPS Situational Reports SMART -T Secure Mobile Anti-Jam Reliable Tactical Terminal SMC Space

  10. 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.......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....

  11. 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 ...

  12. Software-Defined Radio Global System for Mobile Communications Transmitter Development for Heterogeneous Network Vulnerability Testing

    Science.gov (United States)

    2013-12-01

    AbdelWahab, “ 2G / 3G Inter-RAT Handover Performance Analysis,” Second European Conference on Antennas and Propagation, pp. 1, 8, 11–16, Nov. 2007. [19] J...RADIO GLOBAL SYSTEM FOR MOBILE COMMUNICATIONS TRANSMITTER DEVELOPMENT FOR HETEROGENEOUS NETWORK VULNERABILITY TESTING by Carson C. McAbee... MOBILE COMMUNICATIONS TRANSMITTER DEVELOPMENT FOR HETEROGENEOUS NETWORK VULNERABILITY TESTING 5. FUNDING NUMBERS 6. AUTHOR(S) Carson C. McAbee

  13. COMMUNICATION BY MEANS OF THE NEW SOCIAL NETWORKS

    OpenAIRE

    Purice Suzana; Enache Elena; Morozan Cristian

    2012-01-01

    In our days, the electronic communication media is important because the communication forms based on interactivity lead the participants in the act of sending and receiving information to become more than simply issuers, listeners or viewers, integrating them into a dynamic system. In this approach, the study paper aims to prove the relationship between personal development and that of society determined by the new interactive communication instruments. At the individual level, training, edu...

  14. Managing Communications with Experts in Geographically Distributed Collaborative Networks

    Science.gov (United States)

    2009-03-01

    communication. Chat and instant messaging supports enhanced group communication and normally includes features to save this synchronous communication for...means to find and receive information. 5. Online Instruction eLearning : The flow of knowledge is important to a CoP. eLearning contributes to this by...providing a cost efficient way of promoting knowledge flow in a more traditional manner. It has evolved from earlier versions (i.e., computer or

  15. Localisation, Communication and Networking with VLC: Challenges and Opportunities

    OpenAIRE

    Zhang, Rong

    2017-01-01

    The forthcoming Fifth Generation (5G) era raises the expectation for ubiquitous wireless connectivity to enhance human experiences in information and knowledge sharing as well as in entertainment and social interactions. The promising Visible Light Communications (VLC) lies in the intersection field of optical and wireless communications, where substantial amount of new knowledge has been generated by multi-faceted investigations ranging from the understanding of optical communications and si...

  16. 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.

  17. <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...

  18. 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...

  19. Networked control systems with communication constraints :tradeoffs between sampling intervals, delays and performance

    NARCIS (Netherlands)

    Heemels, W.P.M.H.; Teel, A.R.; Wouw, van de N.; Nesic, D.

    2010-01-01

    There are many communication imperfections in networked control systems (NCS) such as varying transmission delays, varying sampling/transmission intervals, packet loss, communication constraints and quantization effects. Most of the available literature on NCS focuses on only some of these aspects,

  20. 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...

  1. Limitations in the design of ancillary service markets imposed by communication network delays

    NARCIS (Netherlands)

    Hermans, R.M.; Jokic, A.; Bosch, van den P.P.J.; Frunt, J.; Kamphuis, I.G.; Warmer, C.J.

    2010-01-01

    Real-time balancing of the European electricity grid will become increasingly dependent on market-based control mechanisms that are enabled by connecting millions of prosumers to an open communication network. The use of communication systems inevitably introduces delays in the energy balancing

  2. 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)

  3. 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

  4. 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

  5. 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...

  6. 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.

  7. Transformation of Traditional Marketing Communications in to Paradigms of Social Media Networking

    OpenAIRE

    Nair, T. R. Gopalakrishnan; Subramaniam, Kumarashvari

    2012-01-01

    Effective Communication for marketing is a vital field in business organizations, which is used to convey the details about their products and services to the market segments and subsequently to build long lasting customer relationships. This paper focuses on an emerging component of the integrated marketing communication, ie. social media networking, as it is increasingly becoming the trend. In 21st century, the marketing communication platforms show a tendency to shift towards innovative te...

  8. 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.

  9. 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.

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

    Science.gov (United States)

    2011-09-01

    Social Networking : – Facebook – MySpace – Friendster 9/1/2011 Content sharing: -You Tube -Flickr -Vimeo -Photobucket Collaborating/ knowledge...Americans use social media tools and Web sites monthly Social networking is now the #1 activity on the web • Twitter: 54 Million users • Facebook ...anyone you don’t know on Facebook or social networking platforms -Don’t post deployment information, when you’re going on vacation or when

  11. 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…

  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. mCRAN : a radio access network architecture for 5G indoor communications

    NARCIS (Netherlands)

    Chandra, Kishor; Cao, Zizheng; Bruintjes, T. M.; Prasad, R. Venkatesha; Karagiannis, G.; Tangdiongga, Eduward; van den Boom, H.P.A.; Kokkeler, A. B J

    2015-01-01

    Millimeter wave (mmWave) communication is being seen as a disruptive technology for 5G era. In particular, 60GHz frequency band has emerged as a promising candidate for multi-Gbps connectivity in indoor and hotspot areas. In terms of network architecture, cloud radio access network (CRAN) has

  14. Improving information dissemination in sparse vehicular networks by adding satellite communication

    NARCIS (Netherlands)

    Kloiber, Bernhard; Strang, Thomas; Spijker, Hanno; Heijenk, Geert

    Information dissemination in pure Vehicular Ad Hoc NETworks (VANETs) such as ITS-G5 becomes problematic when the network is sparse. In situations where the number of vehicles, that can act as a communication node, is insufficiently low, e.g. in rural areas, during night-time or because of a low

  15. 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…

  16. 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…

  17. 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).

  18. Future view of electric power information processing techniques. Architecture techniques for power supply communication network

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Keisuke

    1988-06-20

    Present situations of a power supply communication are described, and the future trend of a power supply information network is reviewed. For the improvement of a transmission efficiency and quality and a cost benefit for the power supply communication, the introduction of digital networks has been promoted. As for a protection information network, since there is the difference between a required communication quality of system protection information and that of power supply operation information, the individual digital network configuration is expected, in addition, the increasing of image information transmission for monitoring is also estimated. As for a business information network, the construction of a broad-band switched network is expected with increasing of image transmission needs such as a television meeting. Furthermore, the expansion to a power supply ISDN which is possible to connect between a telephone, facsimile and data terminal, to exchange various media and to connect between networks is expected with higher communication services in the protection and business network. However, for its practical use, the standardization of various interfaces will become essential. (3 figs, 1 tab)

  19. 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.

  20. 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....