Realistic Mobility Aware Information Gathering in Disaster Areas.
ABSTRACT In this paper, we propose a method for realistic mobility aware information gathering in disaster areas. In the proposed method, a disaster area is divided into a grid, and each node's safety information is held in its pre-defined home grid cells, and it can be referred by sending a query to mobile nodes in its home cells. In this paper, we propose an autonomous adaptable protocol so that it can adapt to a variety of realistic network environments. In order to achieve speedy and high propagation, we combine the notions of store/forward in opportunistic networks and geographical routing in MANETs. In the proposed protocol, if intermediate nodes cannot relay safety information to its home cells by multi-hop communication, they hold it until they meet preceding nodes and re-transmit it as proxies. If a shortest path is not available, a detour is autonomously found. We have evaluated the proposed method under realistic pedestrian flows using our network simulator MobiREAL, and shown that it can work well.
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Conference Proceeding: An Efficient Resilience Mechanism for Data Centric Storage in Mobile Ad Hoc Networks[show abstract] [hide abstract]
ABSTRACT: Data Centric Storage (DCS) is a powerful storage paradigm for wireless ad hoc networks. In mobile ad hoc networks (MANETs), however, the mobility and varying density of nodes may significantly impact the efficiency of data access and the level of data consistency for existing DCS mechanisms. In this paper, we propose an efficient resilience mechanism for data centric storage that supports DCS in mobile environments. We introduce a novel indirection strategy that enables us to distinguish the storage of data at dedicated server nodes from the storage of additional information to locate these servers. Our approach places server location information dynamically in strategic parts of the network based on its current topology. Combining our server location advertisement with any geographic routing protocol, we provide a robust data update and query processing technique for data centric storage in MANETs. We show analytically and by means of experimental evaluations that, despite the additional indirection during packet forwarding, our approach provides superior storage and retrieval performance than the original DCS algorithm even for large amounts of dynamic data.Mobile Data Management, 2006. MDM 2006. 7th International Conference on; 06/2006
Conference Proceeding: MobiREAL Simulator Evaluating MANET Applications in Real Environments.[show abstract] [hide abstract]
ABSTRACT: In this paper, we propose a probabilistic rule-based model to describe behavior of mobile nodes for accurately evaluating performance of MANET applications. The proposed model allows us to describe how mobile nodes change their destinations, routes and speeds/directions based on their positions, surroundings (e.g. neighboring nodes), information obtained from applications, and so on. We have designed and developed a network simulator called MobiREAL based on the proposed methodology. Through experiments, we show importance to simulate MANET applications in realistic environments.13th International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS 2005), 27-29 September 2005, Atlanta, GA, USA; 01/2005
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ABSTRACT: In order for precise evaluation of MANET applications, more realistic mobility models are needed in wireless network simulations. In this paper, we focus on the behavior of pedestrians in urban areas and propose a new method to generate a mobility scenario called Urban Pedestrian Flows (UPF). In the proposed method, we classify pedestrians in a simulation field into multiple groups by their similar behavior patterns (simply called flows hereafter, which indicate how they move around geographic points). Given the observed road density in the target field, we derive using linear programming techniques how many pedestrians per minute follow each flow. Using the derived flows, we generate a UPF scenario which can be used in network simulators. In particular, we have enhanced a network simulator called MobiREAL, which has been developed in our research group, so that we can generate and use the UPF scenario. MobiREAL simulator has three main facilities: the behavior simulator, network simulator and animator. The behavior simulator can generate/delete mobile nodes according to the UPF scenario. The network simulator can simulate MANET protocols and applications. The animator offers elegant visualization of simulation traces as well as graphical user interfaces for facilitating derivation of UPF scenarios. Through several case studies, we show similarity of the derived flows to the observed ones, as well as the metrics that characterize the mobility of the scenario.Proceedings of the 8th International Symposium on Modeling Analysis and Simulation of Wireless and Mobile Systems, MSWiM 2005, Montréal, Quebec, Canada, October 10-13, 2005; 01/2005