Optimal Caching Policy of Stochastic Updating Information in Delay Tolerant Networks
Yahui Wu; Science and Technology on Information Systems Engineering Laboratory, National University of Defense Technology, Changsha ; Mingxing Liu; Science and Technology on Information Systems Engineering Laboratory, National University of Defense Technology, Changsha ; Su Deng; Science and Technology on Information Systems Engineering Laboratory, National University of Defense Technology, Changsha ; Hongbin Huang; Science and Technology on Information Systems Engineering Laboratory, National University of Defense Technology, Changsha ; Yiqi Deng; Department of Computer Science, University College London, London, WC1E 6BT
Computing and Informatics, Tome 33 (2015) no. 3, / Harvested from Computing and Informatics
Text on Computing and Informatics
To increase the speed of information retrieval, one message may have multiple replicas in Delay Tolerant Networks (DTN). In this paper, we adopt a discrete time model and focus on the caching policy of stochastic updating information. In particular, the source creates new version in every time slot with certain probability. New version is usually more useful than the older one. We use a utility function to denote the availability of different versions. To constrain the number of replicas, we propose a probabilistic management policy and nodes to discard information with certain probability determined by the version of the information. Our objective is to find the best value of the probability to maximize the total utility value. Because new version is created with certain probability, nodes other than the source may not know whether the information stored in them is the latest version. Therefore, they can make decisions only according to the local state and decisions based on the local state can be seen as local-policy. We also explore the global-policy, that is, nodes understand the real state. We prove that the optimal policies in both cases conform to the threshold form. Simulations based on both synthetic and real motion traces show the accuracy of our theoretical model. Surprisingly, numerical results show that local-policy is better than the global-policy in some cases.
Publié le : 2015-02-10
Classification:  Parallel and Distributed Computing,  Delay tolerant networks, stochastic updating information, probabilistic management policy, local-policy, global-policy, threshold form 
@article{cai866,
     author = {Yahui Wu; Science and Technology on Information Systems Engineering Laboratory, National University of Defense Technology, Changsha and Mingxing Liu; Science and Technology on Information Systems Engineering Laboratory, National University of Defense Technology, Changsha and Su Deng; Science and Technology on Information Systems Engineering Laboratory, National University of Defense Technology, Changsha and Hongbin Huang; Science and Technology on Information Systems Engineering Laboratory, National University of Defense Technology, Changsha and Yiqi Deng; Department of Computer Science, University College London, London, WC1E 6BT},
     title = {Optimal Caching Policy of Stochastic Updating Information in Delay Tolerant Networks},
     journal = {Computing and Informatics},
     volume = {33},
     number = {3},
     year = {2015},
     language = {en},
     url = {http://dml.mathdoc.fr/item/cai866}
}

Yahui Wu; Science and Technology on Information Systems Engineering Laboratory, National University of Defense Technology, Changsha; Mingxing Liu; Science and Technology on Information Systems Engineering Laboratory, National University of Defense Technology, Changsha; Su Deng; Science and Technology on Information Systems Engineering Laboratory, National University of Defense Technology, Changsha; Hongbin Huang; Science and Technology on Information Systems Engineering Laboratory, National University of Defense Technology, Changsha; Yiqi Deng; Department of Computer Science, University College London, London, WC1E 6BT. Optimal Caching Policy of Stochastic Updating Information in Delay Tolerant Networks. Computing and Informatics, Tome 33 (2015) no. 3, . http://gdmltest.u-ga.fr/item/cai866/