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Traditional trust management schemes developed for wired and wireless ad hoc networks are not well suited for sensor networks due to their higher consumption of resources such as memory and power. In this work, we propose a new lightweight group-based trust management scheme (GTMS) for wireless sensor networks, which employs clustering. Our approach reduces(More)
Physical-activity recognition via wearable sensors can provide valuable information regarding an individual's degree of functional ability and lifestyle. In this paper, we present an accelerometer sensor-based approach for human-activity recognition. Our proposed recognition method uses a hierarchical scheme. At the lower level, the state to which an(More)
Various components of context aware middleware infrastructure work collectively to enable physical spaces to be transformed into computationally active and intelligent environments by providing context synthesis and provision services. In this paper, we discuss the requirement of physically separating the components of a context aware middleware in a(More)
Wireless sensor networks with one static sink often suffer from energy hole problem, which means energy consumption of certain sensors near the sink or on critical paths is much faster than other nodes. Consequently, network partition and isolated nodes are caused. To solve the problem, we propose a Mobile-sink based Energy-efficient Clustering Algorithm(More)
Many energy aware routing algorithms and protocols have been proposed for wireless sensor networks recently to achieve aims like minimum energy consumption, maximized network lifetime, reduced communication latency and overhead etc. The problem of hotspot can not be well addressed under many routing algorithms since some nodes which are on the shortest path(More)
— Wireless sensor networks (WSNs) will play an active role in the 21th Century Healthcare IT to reduce the healthcare cost and improve the quality of care. The protection of data confidentiality and patient privacy are the most critical requirements for the ubiquitous use of WSNs in healthcare environments. This requires a secure and lightweight user(More)
In ad hoc sensor networks, sensor nodes have very limited energy resources , thus energy consuming operations such as data collection, transmission and reception must be kept at a minimum. This paper applies particle swarm optimization (PSO) approach to optimize the coverage in ad hoc sensor networks deployment and to reduce cost by clustering method based(More)
Ubiquitous Computing foresees a massively networked world supporting a population of diverse but cooperating mobile devices where trust relationships between entities are uncertain. Though there have been lots of effort fo-cusing on trust for Ubiquitous Systems, they did not attach enough importance to uncertainty in their model. On the other hand, most of(More)