消費性電子產品的效能與省電一直是重要的研究主題，在提昇效能的同時，也產生對省電技術的需求。省電技術廣泛運用於電子產品中，從虛擬機器伺服器、筆記型電腦、平板電腦到智慧型手機上都有不同的技術以及研究發展。
本研究透過一連串對於Android應用程式的實驗以及硬體測量發現不同應用程式對於中央處理器的使用特徵，而後設計出一套建議系統調整背光亮度以及中央處理器之頻率的規則。透過這個規則，我們可以在維持使用者對於應用程式體驗的同時，達到省電的功能，進而增加電池可供使用的時間。

Over decades, the power saving techniques are broadly used in many different contexts, such as smartphones, laptop computers, tablets and long running servers. In recent years, Android devices have been gaining popularity. Improving the power efficiency for Android devices with limited battery capacity has thus become a important topic.
In this thesis, by conducting a series of experiments on an Android device, we found that the power consumption of the device is quite application dependent. Different applications may have different CPU and backlight scaling requirements (characteristics). Based on this, we develop a power saving approach, which includes two phases. First, the application power consumption characteristics are predetermined based on profiling (i.e. the execution logs and some rules). An Android application (service) then exploits these application specific characteristics to recommend the Android system to perform scaling to the CPU and backlight. Based on our experiments, the proposed approach can achieve power efficiency without affecting the user experience.

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