一個基於移動行為之雲端行動裝置快取資料量最佳化機制

Abstract

雲端計算、可攜式行動裝置以及無線網路的發展，使得人們不論在何時何地，都能取得任何想要 的資料。但人在移動的環境中，需要的資料可能會隨著位置的變化而不同，為了滿足使用者查詢資料 的即時性，將適當的資料量快取(cache)在行動裝置上，可以減少連網向雲端要資料的次數，而降低網 路頻寬的使用量，同時使行動裝置本身的耗電量變小。本研究中，我們將針對手機的耗電量來探討， 利用排隊理論(queueing theory)推導當手機連網查詢資料，最低耗電量時的快取(cache)資料量之數學模 型。透過實驗證明，我們提出之數學模型，的確能找到行動裝置在最低耗電量時所需的資料量，作為 實際應用上的參考。

Due to the recent development of cloud computing, portable mobile devices and wireless network, it can satisfy people’s information needs at any time and in any place. But the needs of people for information may change, when they move to another place. If we cache a proper data volume in mobile devices, the number of requests for information can be reduced, the amount of bandwidth usage can be decreased, and the power consumption of mobile devices can be saved. In this study, the power consumption of mobile phone is adopted for us to find a proper cache data volume in the mobile phones, and we use it to build a mathematical model based on the concept of queueing theory. At last, we prove that our mathematical model indeed can find the best cache data volume in the mobile devices for reference by some experiments.