近來由於行動通訊裝置的廣泛使用，機會網路的應用也變得越來越熱門。因為網路連線的間歇性以及網路拓樸的不穩定，在機會網路上很難運用傳統的路由方法傳遞資料，取而代之的是使用儲存-攜帶-轉傳（store-carry-forward）的方式。然而現有的方法如病毒式路由方式（epidemic routing protocol）會耗費大量的網路頻寬，而基於內文式（context-based）路由則會為了評估合適的轉傳節點而消耗資源。因此機會網路上現存的資料繞送方式都缺乏效率。
因此在我們的論文中，我們進一步加入了一些易得且已知的資訊來幫助我們的方法：基於社群的合作式資料散佈方法(Cooperative Community-based data dissemination Scheme, 簡稱CCDD scheme)以有效率的攜帶及傳遞資料。由於需求區域性的特性，已知的區域性社群資訊可以用來判斷此區域的資料需求。藉由日漸普及的導航資訊，我們可以進一步的決定適合的轉傳節點。而利用合作式快取的技術，我們可以整合節點的快取空間以提升快取效能並避免攜帶重複的資料。此外為了能攜帶最有價值的資料，資料的新舊程度以及熱門度也被用來評估真實的資料效益值。不同於其他的方法只考量單一目標社群，我們的方法將試圖達到系統所有社群效益值的最佳化。實驗果顯示在我們提出的CCDD方法中，系統效益值、快取效率以及資料傳送率上皆能呈現出較好的效果。

Nowadays, applications in opportunistic networks are getting popular due to the widely using of mobile communication devices. In opportunistic networks, since the network connectivity is intermittent as well as the network topology is highly unstable, it is difficult to forward data by traditional routing techniques. Instead, we usually forward data in store-carry-forward mode. However, several existing forwarding algorithms, such as the epidemic routing protocol, consume much network bandwidth. Some other methods, for example context-based algorithms, make considerable effort to estimate suitable relay nodes. Therefore, existing algorithms in opportunistic networks are inefficient.
In the thesis, we further utilize some accessible and well-known information and then proposed the Cooperative Community-based data Dissemination (CCDD) scheme to carry and forward data efficiently. With well-known community information thanks to the Locality of Demand property, data can be delivered to appropriate areas. Using popular navigation information, appropriate relay nodes can be future decided. Next, by applying the cooperative caching technique, cache space of nodes can be integrated to improve cache efficiency and avoid carrying redundant data as well. Besides, to carry the most valuable data, data freshness and popularity are involved to evaluate the actual data utility. Unlike other approaches, the proposed scheme tries to optimize the whole system utility among all communities rather than target community only. Simulation results show that, with the proposed CCDD scheme, system utility is improved as well as better cache efficiency and delivery rate can be obtained.

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