計畫編號：NSC91-2213-E032-013研究期間：200208~200307研究經費：440,000[[sponsorship]]行政院國家科學委員

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計畫編號：NSC91-2213-E032-013研究期間：200208~200307研究經費：440,000行政院國家科學委員

Tamkang University Institutional Repository

????????????????  ????   ??????????????????   ?????????? ?????NSC91-2213-E-032-013- ?????91?08?01??92?07?31? ???????????????(?)     ?????????  ??????????????????????     ?????????  ?????????????     ? ? ? ? 92?10?31?  1???????????????????? ?????????????????? The Design of Cache Invalidation Schemes  in Mobile Computing Environments ?????NSC 91-2213-E-032-013 ?????91? 8? 1?? 92? 7? 31? ???????   ???????  ?????????????????????? ???????  ?、????  ???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? ??????????????????????????????????????????????????????????????????????????????????????????????????????? ?????????????????????????????????????????????????????????????????????????????????????????????????? Tlb ????????????????????????????????????????????????????????????????????????????????????????????  關鍵詞????????????????????????????????????????????????  Abstract  In a mobile computing environment, caching data items at the mobile clients is important as it reduces the data access time and bandwidth utilization. While caching is desirable, it may cause data inconsistency between the server and the mobile clients if their communication is disconnected for a period of time. To ensure information coherence between the cached items and their source items, the server can broadcast invalidation reports to the mobile clients, who then use the reports to update the cached data items.  Cache invalidation is indeed an effective approach to maintaining such data coherence. After careful investigation on the advantages and disadvantages of existing cache invalidation strategies, this research presents a new cache invalidation strategy with different designs and improved performance. Experimental evaluation shows that the new strategy is able to maintain data consistency between the server and mobile clients more effectively and efficiently than the other strategies.  Keywords: Mobile computing environments, servers and clients, cache invalidation, validity (consistency or coherency), bandwidth requirement, communication cost, simulation and performance evaluation..  ?、???????  2??????????????? (user) ???????????????????????????????????????????????????????????????????mobile client????????caching???????????server???????????????????????????????????????????????????????????????????????????????????? ??????????????????????????????????????????????????????????????????????????????cache invalidation strategies, ? [1-10]????????????????????Invalidation Report??? IR?????????????????????????????????????????????????????????????????????????????????????????????????????????????uplink channel??????????????????????????downlink channel?????????????????????? ??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????  ?、?????  ??????????????????? 1. ???????????????????????????????????????????????????IR ??????????????????????????????????????????????????? ID ???????T?????????????????????????? Tlb??? T?? 2. ???????? Tlb??? Tlb?????????????????????????????????? Tlb???????? ID ??????? 3. ????????????????????????????? (1) ???????????????????????????????????? (2) ?? ????????????????????????????????????????????????????????????????Tlb????????? Tlb?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? 4. ????????????????????????????? Tlb?????????? ID ???????????????????? T???????????????? Tlb??  ?????? Tlb?????????????????????????????????????? Tlb?????? 3?????? IR ??? ????????????????????????????????????? Tlb?????????????????????????????????????????????????????????????????????????????????????????????sequence number??????????????????????????????????????????????????????????????reset?? ?????????? 1. ???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? 2. ?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????  ?、??????  ????????????????????? 1. ?????????????????????????????????????????????????????????????? 2. ???????????????????????????????????? Tlb?????????????Tlb??????????????????????? 3. ????????????????????????????????????????????????? 4. ??????????? Tlb????????????????????????????? ????????????????????????????????????? ??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? ????????????????????????????????????????????????????????????????????????????????????????  ?、????  [1] D. Barbara and T. Imielinksi, “Sleepers and Workaholics: Caching Strategies for Mobile Environments,” Proc. 1994 ACM SIGMOD Conf. on Management of Data, pp. 1-12, 1994.  [2] D. Barbara and T. Imielinksi, “Sleepers and Workaholics: Caching Strategies for Mobile Environments (extend version),” MOBIDATA: An Interactive Journal of Mobile Computing, Vol. 1, No. 1, Nov. 1994.  [3] Q. Hu, and D. L. Lee, “Adaptive cache invalidation methods in mobile environments,” Proc. Int’l Conf. on High Performance Distributed Computing, 1997, pp. 264-273.  [4] J. Jing, A. Elmagarmid, A. Helal, and R. Alonso, “Bit-sequences: an adaptive cache invalidation method in mobile client/server environments,” Mobile Networks and Applications, Vol. 31, No. 2, pp.115-127, 1997.  4 [5] K.-L. Tan, J. Cai, and B. C. Ooi, “An evaluation of cache invalidation strategies in wireless environments,” IEEE Tran. on Parallel and Distributed Systems, Vol. 12, No. 8, pp. 789-807, Aug. 2001.   [6] E. Chan, C.-H. Yuen, K.-Y. Lam, and H.W Leung, “An adaptive AVI-based cache invalidation scheme for mobile computing systems,” Proc. Int’l Conf. on Database and Expert Systems Applications, 2000.  [7] K.-L. Wu, P. S. Yu, and M.-S. Chen, “Energy-efficient caching for wireless mobile computing,” Proc. Int’l Conf. on Data Engineering, Feb. 1996, pp. 336-343.  [8] S. H. Nam, I. Y. Chung, and C.-S. Hwang, “An efficient cache invalidation scheme for mobile wireless environments,” Proc. Int’l Conf. on Parallel and Distributed Systems, 2001, pp.289-296.  [9] Q. Hu and D. L. Lee, “Cache Algorithms Based on Adaptive Invalidation Reports for Mobile Environments,” Cluster Computing, Vol. 1, pp. 35-90, 1998.  [10] A. Kahol, S. Khurana, S. K. S. Gupta, and P. K. Srimani, “A Strategy to Manage Cache Consistency in a Disconnected Distributed Environment,” IEEE Trans. on Parallel and Distributed Systems, Vol. 12, No. 7, pp. 686-700, July 2001. 

The Design of Cache Invalidation Schemes in Mobile Computing Environments

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[[alternative]]The Design of Cache Invalidation Schemes in Mobile Computing Environments

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