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A large class of Wireless Sensor Networks (WSN) applications involve a set of isolated urban areas (e.g., urban parks or building blocks) covered by sensor nodes (SNs) monitoring environmental parameters. Mobile sinks (MSs) mounted upon urban vehicles with fixed trajectories (e.g., buses) provide the ideal infrastructure to effectively retrieve sensory data(More)
IntroductIon Mobile ad hoc networks are self-organizing and self-configuring multi-hop wireless networks capable of adaptive re-configuration when they are affected by node mobility. A mobile ad hoc network is composed of peer nodes with equal networking capabilities which are able to function as mobile routers i.e., to forward packets and maintain routes.(More)
This paperl discusses the efi-iciency of a parallel text retrieval system that is based on the Vector Space Model. Specifically , we describe a general parallel retrieval algorithm for use with this model, the application of the algorithm in the FIRE system [I], and its implementation on the high performance GCe131512 Parsytec parallel machine [2]. The use(More)
Organization, scalability and routing have been identified as key problems hindering viability and commercial success of mobile ad hoc networks. Clustering of mobile nodes among separate domains has been proposed as an efficient approach to address those issues. In this work, we introduce an efficient distributed clustering algorithm that uses both location(More)
—Many studies in recent years have considered the use of mobile sinks (MS) for data gathering in wireless sensor networks (WSN), so as to reduce the need for data forwarding among the sensor nodes (SN) and thereby prolong the network lifetime. Moreover, in practice, often the MS tour length has to be kept below a threshold, usually due to timeliness(More)
Lately, many systems and websites add personalization functionalities among their provided services. However, for large document collections it is difficult for the user to direct effective queries from the beginning of his/her search, since accurate query terms may not be known in advance. In this paper we describe a system that applies a hybrid approach(More)
Clustering is a promising approach for building hierarchies and simplifying the routing process in mobile ad-hoc network environments. The main objective of clustering is to identify suitable node representatives, i.e. cluster heads (CHs), to store routing and topology information and maximize clusters stability. Traditional clustering algorithms suggest CH(More)
Mobile sinks (MS) mounted upon urban vehicles with fixed trajectories (e.g. buses) provide the ideal infrastructure to effectively retrieve sensory data from isolated Wireless Sensor Network (WSN) fields. Existing approaches involve either single-hop transfer of data from sensors that lie within the MS's range or heavy involvement of network periphery nodes(More)
This paper mainly discusses the eeciency of PFIRE system , a parallel VSM-based text retrieval system running on the GCel3/512 Parsytec machine, as well as the eeec-tiveness of the corresponding pre-existing serial FIRE system. Concerning PFIRE, the use of suitable data sharing and load balancing techniques in combination with speciic pipelining techniques(More)