With increasing advances in hardware technology, handheld devices, such as smart phones, PDAs, etc., are becoming more and more powerful and feature-rich, which also implies higher power consumption. Battery life on handheld devices is limited and power conservation is becoming a major concern. Most of the power management systems on handheld devices are still relatively primitive. In this project, we will develop an advanced power optimization framework to achieve better power management, especially focusing on multi-core handheld devices. The framework includes (a) a power management service in the cloud, which maintains a repository of power measurement data for various applications and power management policies obtained by analyzing these data, and (b) the power management daemon on the mobile device in charge of power management.