528,541 research outputs found

    Taking Cooperative Decisions in Group-Based Wireless Sensor Networks

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    Several studies have demonstrated that communications are more efficient when cooperative group-based architectures are used in wireless sensor networks (WSN). This type of architecture allows increasing sensor nodes' lifetime by decreasing the number of messages in network. But, the main gap is to know how to take cooperative decisions in order to make the right communication. In this paper, we analyze the main aspects related to collaborative decisions in WSNs. A mathematical analysis will be presented in order to take the correct decision. Finally, the simulations will show the efficiency of the method used to make cooperative decisions in WSNs. © 2011 Springer-Verlag.García Pineda, M.; Lloret, J.; Sendra Compte, S.; Rodrigues, JJPC. (2011). Taking Cooperative Decisions in Group-Based Wireless Sensor Networks. En Lecture Notes in Computer Science. Springer Verlag (Germany). 61-65. doi:10.1007/978-3-642-23734-8_9S6165Garcia, M., Bri, D., Sendra, S., Lloret, J.: Practical Deployments of Wireless Sensor Networks: a Survey. Int. Journal on Advances in Networks and Services 3(3-4), 170–185 (2010)Lloret, J., Garcia, M., Tomas, J.: Improving Mobile and Ad-hoc Networks performance using Group-Based Topologies. In: Wireless Sensor and Actor Networks II. IFIP, vol. 264, pp. 209–220 (2008)Garcia, M., Lloret, J.: A Cooperative Group-Based Sensor Network for Environmental Monitoring. In: Luo, Y. (ed.) CDVE 2009. LNCS, vol. 5738, pp. 276–279. Springer, Heidelberg (2009)Garcia, M., Sendra, S., Lloret, J., Lacuesta, R.: Saving Energy with Cooperative Group-Based Wireless Sensor Networks. In: Luo, Y. (ed.) CDVE 2010. LNCS, vol. 6240, pp. 73–76. Springer, Heidelberg (2010)Parsa, S., Parand, F.-A.: Cooperative decision making in a knowledge grid environment. Future Generation Computer Systems 23, 932–938 (2007)Soubie, J.-L., Zaraté, P.: Distributed Decision Making: A Proposal of Support Through Cooperative Systems. J. Group Decisions and Negotiation 14(2), 147–158 (2005)Kraemer, K.L., King, J.L.: Computer-based systems for cooperative work and group decision making. ACM Computer Survey 20(2), 115–146 (1988)Kernan, J.B.: Choice Criteria, Decision Behavior, and Personality. Journal of Marketing Research 5(2), 155–164 (1968

    The Performability Manager

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    The authors describe the performability manager, a distributed system component that contributes to a more effective and efficient use of system components and prevents quality of service (QoS) degradation. The performability manager dynamically reconfigures distributed systems whenever needed, to recover from failures and to permit the system to evolve over time and include new functionality. Large systems require dynamic reconfiguration to support dynamic change without shutting down the complete system. A distributed system monitor is needed to verify QoS. Monitoring a distributed system is difficult because of synchronization problems and minor differences in clock speeds. The authors describe the functionality and the operation of the performability manager (both informally and formally). Throughout the paper they illustrate the approach by an example distributed application: an ANSAware-based number translation service (NTS), from the intelligent networks (IN) area

    Desktop multimedia environments to support collaborative distance learning

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    Desktop multimedia conferencing, when two or more persons can communicate among themselves via personal computers with the opportunity to see and hear one another as well as communicate via text messages while working with commonly available stored resources, appears to have important applications to the support of collaborative learning. In this paper we explore this potential in three ways: (a) through an analysis of particular learner needs when learning and working collaboratively with others outside of face-to-face situations; (b) through an analysis of different forms of conferencing environments, including desktop multimedia environments, relative to their effectiveness in terms of meeting learner needs for distributed collaboration; and (c) through reporting the results of a formative evaluation of a prototype desktop multimedia conferencing system developed especially for the support of collaborative learning. Via these analyses, suggestions are offered relating to the functionalities of desktop multimedia conferencing systems for the support of collaborative learning, reflecting new developments in both the technologies available for such systems and in our awareness of learner needs when working collaboratively with one other outside of face-to-face situations

    Realizing live sequence charts in SystemVerilog.

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    The design of an embedded control system starts with an investigation of properties and behaviors of the process evolving within its environment, and an analysis of the requirement for its safety performance. In early stages, system requirements are often specified as scenarios of behavior using sequence charts for different use cases. This specification must be precise, intuitive and expressive enough to capture different aspects of embedded control systems. As a rather rich and useful extension to the classical message sequence charts, live sequence charts (LSC), which provide a rich collection of constructs for specifying both possible and mandatory behaviors, are very suitable for designing an embedded control system. However, it is not a trivial task to realize a high-level design model in executable program codes effectively and correctly. This paper tackles the challenging task by providing a mapping algorithm to automatically synthesize SystemVerilog programs from given LSC specifications

    A Taxonomy of Self-configuring Service Discovery Systems

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    We analyze the fundamental concepts and issues in service discovery. This analysis places service discovery in the context of distributed systems by describing service discovery as a third generation naming system. We also describe the essential architectures and the functionalities in service discovery. We then proceed to show how service discovery fits into a system, by characterizing operational aspects. Subsequently, we describe how existing state of the art performs service discovery, in relation to the operational aspects and functionalities, and identify areas for improvement

    The Art of Engaging: Implications for Computer Music Systems

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    The art of engaging with computer music systems is multifaceted. This paper will provide an overview of the issues of interface between musician and computer, cognitive aspects of engagement as involvement, and metaphysical understandings of engagement as proximity. Finally, this paper will examine implications for the design of computer music systems when these issues are taken into account

    Process algebra for performance evaluation

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    This paper surveys the theoretical developments in the field of stochastic process algebras, process algebras where action occurrences may be subject to a delay that is determined by a random variable. A huge class of resource-sharing systems – like large-scale computers, client–server architectures, networks – can accurately be described using such stochastic specification formalisms. The main emphasis of this paper is the treatment of operational semantics, notions of equivalence, and (sound and complete) axiomatisations of these equivalences for different types of Markovian process algebras, where delays are governed by exponential distributions. Starting from a simple actionless algebra for describing time-homogeneous continuous-time Markov chains, we consider the integration of actions and random delays both as a single entity (like in known Markovian process algebras like TIPP, PEPA and EMPA) and as separate entities (like in the timed process algebras timed CSP and TCCS). In total we consider four related calculi and investigate their relationship to existing Markovian process algebras. We also briefly indicate how one can profit from the separation of time and actions when incorporating more general, non-Markovian distributions
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