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Muhammad Taqi RAZA Zeeshan Hameed MIR Ali Hammad AKBAR Seung-Wha YOO Ki-Hyung KIM
Target tracking is one of the key applications of Wireless Sensor Networks (WSNs) that forms basis for numerous other applications. The overall procedures of target tracking involve target detection, localization, and tracking. Because of the WSNs' resource constraints (especially energy), it is highly desired that target tracking should be done by involving as less number of sensor nodes as possible. Due to the uncertain behavior of the target and resulting mobility patterns, this goal becomes harder to achieve without predicting the future locations of the target. The presence of a prediction mechanism may allow the activation of only the relevant sensors along the future course, before actually the target reaches the future location. This prior activation contributes to increasing the overall sensor networks lifetime by letting non-relevant nodes sleep. In this paper, first, we introduce a Yaw rate aware sensor wAkeup Protocol (YAP) for the prediction of future target locations. Second, we present improvements on the YAP design through the incorporation of adaptability. The proposed schemes are distributive in nature, and select relevant sensors to determine the target track. The performance of YAP and A-YAP is also discussed on different mobility patterns, which confirms the efficacy of the algorithm.
The AODV (Ad Hoc On-Demand Distance Vector) protocol is one of the typical reactive routing protocols in Ad Hoc networks, in that mobile nodes initiate routing activities only in the presence of data packets in need of a route. In this paper, we focus upon the local repair mechanism of AODV. When a link is broken, the upstream node of the broken link repairs the route to the destination by initiating a local route discovery process. The process involves the flooding of AODV control messages in every node within a radius of the length from the initiating node to the destination. In this paper, we propose an efficient local repair scheme for AODV, called AELR (AODV-based Efficient Local Repair). AELR utilizes the existing routing information in the downstream intermediate nodes which have been on the active route to the destination before a link break occurs. AELR can reduce the flooding range of AODV control messages and the route recovery time for route recovery because it can repair a route through the nearby downstream intermediate nodes. The performance results show that AELR can achieve faster route recovery than the local repair mechanism of AODV.
Shafique Ahmad CHAUDHRY Ali Hammad AKBAR Ki-Hyung KIM
The IEEE 802.15.4 standard for Low Power Wireless Personal Area Networks (LoWPANs) has emerged as a promising technology to bring the envisioned ubiquitous paradigm, into realization. Considerable efforts are being carried on to integrate LoWPANs with other wired and wireless IP networks, in order to make use of pervasive nature and existing infrastructure associated with IP technologies. Provisioning of service discovery and network selection in such pervasive environments puts heavy communication and processing overhead in networks with highly constrained resources. Localization of communication, through accessing the closest services, increases the total network capacity and increases the network life. We present a hierarchical service discovery architecture based on SSLP, in which we propose directory proxy agents to act as cache service for directory agent, in order to localize the service discovery communication and access the closest services. We also propose algorithms to make sure that service users are connected to the closest proxy agent in order to access the closest service in the vicinity. The results show that our architecture and algorithms help finding the closest services, reduce the traffic overhead for service discovery, decrease the service discovery time, and save nodes' energy considerably in 6LoWPANs.