QoS is an issue of intrinsic importance in service oriented applications. Although many service oriented applications deliver their promised services yet it is rather difficult for them to maintain the QoS from user p...
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ISBN:
(纸本)9781424416509
QoS is an issue of intrinsic importance in service oriented applications. Although many service oriented applications deliver their promised services yet it is rather difficult for them to maintain the QoS from user perspective. In this paper we develop an approach based on multi-agent system that helps to achieve the desired level of QoS by negotiating and coordinating between agents at the application layer. These service oriented applications may use the Web services of an agent based service in order to realize a service oriented architecture. In this paper, we propose an agent based approach to address QoS issues in service oriented applications. This approach is based on a unified framework that is applicable to both Web services and agent based services.
Although Web services are generally envisioned as being stateless, some of them are implicitly stateful. The reason is that the Web services often work as front-ends to enterprise systems and are used in a session-ori...
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Although Web services are generally envisioned as being stateless, some of them are implicitly stateful. The reason is that the Web services often work as front-ends to enterprise systems and are used in a session-oriented way by the clients. Contrary to the case of stateless services, for a stateful Web service there exist constraints to the order in which the operations of the service may be invoked. However, specification of such constraints is not a standard part of a Web service interface, and compliance with such constraints is not checked by the standard Web service development tools. Therefore, we propose in this paper to extend a web service interface by a constraint definition that is based on behavior protocols. Also, we implemented a tool that checks whether a given BPEL code complies with the constraints of all stateful web services it communicates with. The key idea behind the tool is to translate the BPEL code into Java and then to check the Java program using Java PathFinder with behavior protocol extension.
Body sensor networks are an interesting emerging application of wireless sensor networks to improve healthcare and the quality of life. Current research has mainly focused on single-hop networks, although some works c...
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Body sensor networks are an interesting emerging application of wireless sensor networks to improve healthcare and the quality of life. Current research has mainly focused on single-hop networks, although some works clearly show advantages of multi-hop architectures. In this paper, we model probabilistic connectivity in such multi-hop body sensor networks. Instead of using a circular coverage area, a more accurate model is defined based on the path loss along the human body. Further, we propose improvements to CICADA, a cross-layer multi-hop protocol that handles both medium access and the routing of data in BSNs. CICDA is slot-based and uses schemes to allocate these slots. Preliminary results for two reliability improvements are given: randomization of the schemes and repeating the schemes received from a parent node. We show that these improvements positively affect the throughput of the network and lead to fewer retransmissions. In both cases, the energy consumption of the nodes is hardly influenced.
作者:
Rafael DuqueCrescencio BravoCHICO Research Group
Department of Information Systems and Technologies College of Computer Science Engineering University of Castilla La Mancha Ciudad Real Spain
Pair programming practices usually take place on a single computer where two programmers collaborate, taking on the roles of driver and observer. This article presents COLLECE, a groupware system to support synchronou...
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Pair programming practices usually take place on a single computer where two programmers collaborate, taking on the roles of driver and observer. This article presents COLLECE, a groupware system to support synchronous distributed pair programming practices, and includes a variety of experimental activities in which two groups of programmers were involved to solve various programming problems. The first group carried out the activities by employing distributed pair programming practices using COLLECE, while the second group of solo programmers followed traditional programming practices. These experimental activities were used to conduct comparative studies of work productivity and program quality.
This chapter presents a general overview of parallel approaches for multiobjective optimization. For this purpose, we propose a taxonomy for parallel metaheuristics and exact methods. This chapter covers the design as...
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Self-organizing techniques have successfully been used to optimize software systems, such as optimization of route stability in ad hoc network routing and optimization of the use of storage space or processing power u...
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Motivation - In some situations EID's high-level visual design principles can be difficult to apply. A more concrete design methodology would make the framework more accessible for interface designers. research ap...
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ISBN:
(纸本)9781847998491
Motivation - In some situations EID's high-level visual design principles can be difficult to apply. A more concrete design methodology would make the framework more accessible for interface designers. research approach - Graphics research was reviewed across a number of fields. The Visualisation Reference Model was identified as a useful model that could be used alongside EID's visual design principles. A case study is used to demonstrate this approach. Findings/Design - Supplementing a work domain analysis with a task analysis can reveal how information requirements are used. This allows data transformations and visual mapping to be carried out to generate visual components in an ecological interface design. Take away message - Task analysis not only improves the quality of our information requirements, it can also inform the visual design process.
Message delivery in sparse Mobile Ad hoc networks (MANETs) is difficult due to the fact that the network graph is rarely (if ever) connected. A key challenge is to find a route that can provide good delivery performan...
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ISBN:
(纸本)9781595936844
Message delivery in sparse Mobile Ad hoc networks (MANETs) is difficult due to the fact that the network graph is rarely (if ever) connected. A key challenge is to find a route that can provide good delivery performance and low end-to-end delay in a disconnected network graph where nodes may move freely. This paper presents a multidisciplinary solution based on the consideration of the so-called small world dynamics which have been proposed for economy and social studies and have recently revealed to be a successful approach to be exploited for characterising information propagation in wireless networks. To this purpose, some bridge nodes are identified based on their centrality characteristics, i.e., on their capability to broker information exchange among otherwise disconnected nodes. Due to the complexity of the centrality metrics in populated networks the concept of ego networks is exploited where nodes are not required to exchange information about the entire network topology, but only locally available information is considered. Then SimBet Routing is proposed which exploits the exchange of pre-estimated "betweenness' centrality metrics and locally determined social "similarity' to the destination node. We present simulations using real trace data to demonstrate that SimBet Routing results in delivery performance close to Epidemic Routing but with significantly reduced overhead. Additionally, we show that SimBet Routing outperforms PRoPHET Routing, particularly when the sending and receiving nodes have low connectivity. Copyright 2007 ACM.
Location-based multi-player games are currently being pushed by the industry, one main factor being that highly-accurate positioning technologies like GPS as well as broadband mobile networks like UMTS are finally get...
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Protocol development in Mobile Ad hoc networks (MANET) has been a hot topic for many years, yet the performance exhibited from recent deployments [1] is still not optimal and not suitable for large scale practical use...
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Protocol development in Mobile Ad hoc networks (MANET) has been a hot topic for many years, yet the performance exhibited from recent deployments [1] is still not optimal and not suitable for large scale practical use. Stability of transmission is a critical aspect in mobile ad hoc networks, as by improving the stability of end-to-end transmission, the network could deliver more consistent service and achieve efficiency gains. We propose a protocol architecture which aims to improve the stability of transmission inside MANET using limited additional information based on the location of wireless nodes. The draft architecture and the initial progress in this project are also presented in this paper.
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