無線隨意網路提供了一個不需要基礎建設的網路環境，適合應用在臨時需要網路來通訊的情況。通常為了提升整體網路的效能，最常採用的方法就是資料快取技術。而只要環境下的資料會隨時間異動，我們就必須面對快取資料一致性的問題。但傳統行動計算環境的快取資料一致性方法並不適合用在無線隨意網路中，因為傳統行動計算環境中資料傳送的方式為單點跳躍，客戶端所需的資料若被異動，可以很有效率的直接向伺服器端索取新資料。但在無線隨意網路中，因為是使用多點跳躍的傳送方式，客戶端無法有效率地向伺服端直接取得異動的新資料，取而代之的是向鄰近的節點取得快取的新資料內容。因此，在無線隨意網路的快取資料一致性研究上，我們還必須加入“資料搜尋”的方法，來設計一個適合的快取一致性策略。
針對在無線隨意網路中的快取資料一致性問題，我們在本篇論文中提出了一個資料驗證及搜尋策略，減少不必要的能源及封包浪費。模擬實驗結果證明我們的方法能明顯地減少取得一個查詢資料所需的跳躍數(hop count)，因而降低了查詢等待時間。

Mobile Ad Hoc Networks (MANET) provides a network environment without pre-existing infrastructure. In order to improve the communication performance of MANET, a well-known approach is to cache the required data items. If the data items are allowed to be updated, we must resolve the cache consistency problem. Due to the multihop-nature of a MANET, prior cache invalidation strategies for wireless networks are not suitable for MANET. In a MANET, it is more efficient for a client to get a queried data item from its neighbor nodes rather than directly from its data source.
In this paper, we propose a cache consistency strategy, called New Cache Invalidation Scheme (NCIS). In NCIS, we design a new scheme to search for a queried data item in the network. NCIS reduces the packets counts and energy consumption for accessing a queried data item. To take advantages of different cooperative cache schemes, we integrate NCIS with different cooperative cache schemes. Different cooperative cache schemes offer different additional information for NCIS. By using this information, we improve the performance on NCIS. Simulation results show that NCIS decreases the number of hops in getting a queried data item, and thus reduce the query response time

1. L. Yin; G. Cao, ”Supporting cooperative caching in ad hoc networks”, Mobile Computing, IEEE Transactions on, Volume 5, Issue 1, Jan. 2006
2. G. Cao; L. Yin; Das, C.R, “Cooperative cache-based data access in ad hoc networks”, IEEE Trans. On Computer, Volume 37, Issue 2, Feb. 2004
3. J. Cho; S. Oh; J. Kim; H. Ho Lee; J. Lee, “Neighbor caching in multi-hop wireless ad hoc networks”, IEEE Communications Letters, Volume 7, Issue 11, Nov. 2003
4. L. Yin; G. Cao, “Balancing the tradeoffs between data accessibility and query delay in ad hoc networks”, IEEE Symposium on Reliable Distributed Systems(SRDS), Oct. 2004
5. Yu Du; Gupta, S.K.S.; “COOP – A cooperative caching service in MANETs”, Autonomic and Autonomous Systems and International Conference on Networking and Services, 2005. ICAS-ICNS 2005, Oct. 2005
6. Daniel Barbara and Tomasz Imielinski. “Sleeper and Workaholics: Caching Strtegies in Mobile Environments,” Proc. ACM SIGMOD, pp.1-12, 1994
7. K. L. Wu, P. S. Yu and M. S. Chen. “Energy-Efficient Caching for Wireless Mobile Computing,” Proc. 20th Int’l Conf. on Data Eng, p.p. 336-345,1996
8. K. L. Tan, J. Cai. “Broadcast-based group invalidation: An energy efficient cache invalidation scheme,” Information Science 100, p.p. 229-254,1997
9. J. Cai. And K. L. Tan, “Energy-efficient selective cache invalidation,” Wireless Networks 5, pp. 489-502,1999
10. Guohong Cao, “A Scalable Low-Latency Cache Invalidation Strategy for Mobile Environments,” IEEE Trans. on Knowledge and Data Engineering, vol 15, no 5, pp.1251-1265,2003
11. S. Lim, W. Lee, G. Cao, and C. Das, ``Performance Comparison of Cache Invalidation Strategies for Internet-based Mobile Ad Hoc Networks,'' IEEE International Conference on Mobile Ad-hoc and Sensor Systems (MASS), 2004.
12. Y.C Tseng et al. “The broadcast storm problem in a mobile ad hoc network,” Wireless Networks, Volume 8, Issue 2/3, PP. 153 - 167, 2002
13. C. E. Perkins; E. M. Royer, “Ad-hoc on-demand distance vector routing”, in Proc. IEEE WMCSA ’99, pp. 90-100, Feb. 1999
14. C. E. Perkins; E. M. Royer; S. Das, “Ad-hoc on-demand distance vector(AODV) routing”, Internet Draft, draft-intf-manet-aodv-13.txt, Feb. 2003.
15. L. Feeney and M. Nilsson, “Investigating the Energy Consumption of a Wireless Network Interface in an Ad Hoc Networking Environment”, in Proceedings of IEEE INFOCOM, Anchorage, AK, 2001