無線隨意網路(MANET)提供了一個不需要基礎設施的網路環境，適用於即時通訊但無基礎設施的情況(例如：戰地通訊、災區救援等)，為了提升整體隨意網路的存取資料效率，過去最常用的方法為資料備份(Data Replica)技術，但資料會隨著時間經過而改變，所以必須把資料一致性(Data Consistency)的議題納入考量。
在傳統的行動計算網路環境中，資料的傳遞是屬於單點跳躍(Single-hop)，節點能直接與伺服器連線，不需要其他節點的轉送，所以當資料有變動時，節點可以很快地與伺服器溝通取得最新的內容；而在無線隨意網路中，節點有移動性並且使用的是多點跳躍(Multi-Hop)的傳送方式，也就是節點與伺服器的距離，通常需要多個節點幫忙轉送才能送達伺服器。
在無線隨意網路中的資料一致性和快取管理議題上，本研究提供了一種樹狀結構網路拓樸和資料快取驗證策略，樹中的節點可以幫忙伺服器回應資料查詢以及驗證資料，達到減少能源浪費及能夠更快的獲得有效資料。經由實驗模擬的結果也證明了此方法可以減少能源消耗且縮短要求資料時的回應時間。

A Mobile Ad Hoc Network (MANET) is a wireless network environment without pre-existing infrastructure, which can be used in wars or in catastrophe rescue operations. Unlike traditional mobile computing environments, a node in a MANET needs to use multi-hop communication to access the data from the server of a database.
Due to the multi-hop nature of communication in MANETs, the existing data searching and caching policies for mobile computing environment cannot be readily applied. This thesis proposes a tree-based cooperative data cache scheme, abbreviated to TBOC, for MANETs. In TBOC a tree rooted at the server is constructed to help cache data for the whole network. The cached data at the nodes in the tree are kept consistent with the server. A node in the tree helps to answer a query in two respects: provides the answer for the query or validates the cached data for the node issuing the query. According the simulation results, TBOC outperforms the existing methods including ACOD and MTS in terms of query response time and energy consumptions.

[1] Sunho Lim , Wang-Chien Lee , Guohong Cao , Chita R. Das “Cache invalidation strategies for internet-based mobile ad hoc networks,” Computer Communications, vol. 30 , no. 8 , 2007, pp. 1854–1869
[2] Sunho Lim , Wang-Chien Lee , Guohong Cao , Chita R. Das , “Performance comparison of cache invalidation strategies for Internet-based mobile ad hoc networks, ” IEEE International Conference on Mobile Ad-hoc and Sensor System , 2004.
[3] Daniel Barbara and Tomasz Imielifiski , “Sleepers and Workaholics: Caching Strategies in Mobile Environments,” Proceedings of ACM SIGMOD , 1994 , pp. 1-12
[4] Chi-Yin Chow, Hong Va Leong and Alvin T. S. “GroCoca: Group-based Peer-to-Peer Cooperative Caching in Mobile Environment,” IEEE Journal on selected areas in communications, vol. 25, no. 1, January 2007
[5] Hassan Artail, Haidar Safa, Khaleel Mershad, Zahy Abou-Atme and Nabeel Sulieman, “COACS: A Cooperative and adaptive Caching System for MANETs,” IEEE Transactions on mobile computing, vol. 7, No. 8, August 2008
[6] Guohung Cao , “A Scalable Low-Latency Cache Invalidation Strategy for Mobile Environments,” IEEE Transactions on Knowledge and Data Engineering , volum15 , Issue 5 , 2003, pp. 1251-1265
[7] Liangzhong Yin and Guohong Cao , “Supporting Cooperative Caching in Ad Hoc Networks,” IEEE Transactions on Mobile Computing , Vol. 5 , No. 1 , January 2006
[8] Yu Du, Sandeep K.S. Gupta , Georgios Varsamopoulos, “Improving on-demand data access efficiency in MANETs with cooperative caching,” Ad Hoc Networks, July 2009, pp. 579–598
[9] Y. Leu , Jen-Jou Hung and Ming-Ben Lin , “A new cache invalidation and searching policy for mobile ad hoc networks,” WSEAS Transactions on Computers Research , vol. 2 , 2007 , pp. 66-72
[10] V.D Tracy Camp , Jeff Boleng , “A survey of mobility models for ad hoc network research,” Wireless Communications and Mobile Computing , vol. 2 , 2002 ,pp. 483-502
[11] G. Zipf , Human Behavior and the Principle of Least Effort. Addison Wesley, 1949
[12] L. Feeney and M. Nilsson, “Investigating the Energy Consumption of a Wireless Network Interface in an Ad Hoc Networking Environment,” IEEE Computer and Communications Societies, Vol. 3, pp. 1548-1557, August 2002
[13] S. Lim, W.-C. Lee, G. Cao, and C. R. Das, “A novel caching scheme for improving internet-based mobile ad hoc networks performance,” Ad Hoc Networks, vol. 4, no. 2, 2006, pp. 225-239
[14] J.-L. Huang and M.-S. Chen, “On the effect of group mobility to data replication in ad hoc networks,” IEEE Transactions on Mobile Computing, vol. 5, no.11, pp. 1515-1532, Nov. 2006.
[15] Y. Sawai, M. Shinohara, A. Kanzaki, T. Hara, and S. Nishio, “Consistency management among replicas using a quorum system in ad hoc networks,” in 7th International Conference on Mobile Data Management, 2006, May 2006, pp. 128-128
[16] B. Tang, H. Gupta, and S. Das, “Benefit-based data caching in ad hoc networks,” IEEE Transactions on Mobile Computing , vol. 7, no. 3, March 2008, pp. 289-304
[17] J. Cao, Y. Zhang, G. Cao, and L. Xie, “Data consistency for cooperative caching in mobile environments,” Computer, vol. 40, no. 4, April 2007, pp. 60-66
[18] J. Cao, Y. Zhang, L. Xie, and G. Cao, “Consistency of cooperative caching in mobile peer-to-peer systems over MANET,” in 25th IEEE International Conference on Distributed Computing Systems, 2005, June 2005, pp. 573-579
[19] N. Chand, R. C. Joshi, and M. Misra, “Cooperative caching strategy in mobile ad hoc networks based on clusters,” Wireless Personal Communications, vol. 43, 2007.
[20] N. Chand, R. C. Joshi, and M. Misra, “Cooperative caching in mobile ad hoc networks based on data utility,” Mobile Information Systems, vol. 3, 2007.