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Cable-Based Moving Reachability with Mobile Sensors
Xiaoping Wang, Shanshan Li, Mo Li and Baijian Yang

In wireless sensor networks, mobile sensors are often employed to enhance the sensing coverage and improve detection accuracy. Current approaches typically assume mobile sensors have the capability to move arbitrarily. However, sensors with unlimited mobility are very complex to manufacture and are often unrealistic in many real life applications. In this article, we study the use of cable-based mobile sensors which can move to different locations along pre-deployed cables to accomplish sensing tasks. A target area is said to be reachable if any point in the area can be covered by at least one mobile sensor moving along the cable within a specified delay bound. The goal of this study is to solve the k-reachability problem with deploying minimum number of mobile sensors along the cable. When events occur, some mobile sensors need to move to the target area for further investigation where the rest of the sensors may be repositioned to maintain the balance of reachability within the area. We prove the problem is NP-hard and present heuristic algorithms to solve the problem. The correctness of the algorithm is proved and theoretical bounds of our algorithms are analyzed in this article. The effectiveness and the performance of our work are evaluated through comprehensive simulations. The results further demonstrate our proposal can be applied in real life applications with good performance and low overhead.

Keywords: Mobile sensor; cable-based scheduling; sensor coverage; k-reachability; repositioning

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