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Context-awareness is an essential requirement for pervasive computing applications, which enables them to adapt and perform tasks based on context. One of the adaptive features of context-awareness is contextual reconfiguration. Contextual reconfiguration involves discovering remote service(s) based on context and binding them to the application components to realize new behaviors, which may be needed to satisfy user needs or to enrich user experience. One of the steps in the reconfiguration process involves a remote lookup to discover the service(s) based on context. This remote lookup process provides the largest contribution to reconfiguration time and this is due to fact that the remote calls are much slower than local calls. Consequently, it affects system performance. In pervasive computing applications, this may turn out to be undesirable in terms of user experience. Moreover, other distributed applications using the network may be affected as every remote method call decreases the amount of bandwidth available on the network. Various systems provide reconfiguration support and offer high-level reconfiguration directives to develop adaptive context-aware applications, but do not address this performance bottleneck. We address this issue and implement seamless caching of virtual stubs within our PCRA1 for improved performance. In this paper we present and describe our transparent caching support and also provide its performance evaluation., Comment: arXiv admin note: text overlap with arXiv:1108.1472 by other authors

Wireless networks are a common place nowadays and almost all of the modern devices support wireless communication in some form. These networks differ from more traditional computing systems due to the ad-hoc and spontaneous nature of interactions among devices. These systems are prone to security risks, such as eavesdropping and require different techniques as compared to traditional security mechanisms. Recently, secure device pairing in wireless environments has got substantial attention from many researchers. As a result, a significant set of techniques and protocols have been proposed to deal with this issue. Some of these techniques consider devices equipped with infrared, laser, ultrasound transceivers or 802.11 network interface cards; while others require embedded accelerometers, cameras and/or LEDs, displays, microphones and/or speakers. However, many of the proposed techniques or protocols have not been implemented at all; while others are implemented and evaluated in a stand-alone manner without being compared with other related work [1]. We believe that it is because of the lack of specialized tools that provide a common platform to test the pairing methods. As a consequence, we designed such a tool. In this paper, we are presenting design and development of the Pairing Simulator (PSim) that can be used to perform the analysis of device pairing methods., Comment: 12Pages