Studies on design and development of energy-aware middleware for mobile terminals

在视频的流媒体播放中，便携式无线设备需要消耗大量的电能进行视频数据的解码和无线通信。因此，需要控制功率消耗，使得电池寿命可以延长到期望的回放持续时间和/或为其他应用留下指定百分比的电池容量。在这项研究中，我们提出了一种电池感知的视频流系统，考虑到每个用户指定的视频质量偏好和便携式无线设备的剩余电量，可以在指定的时间内播放。在该系统中，通过对视频进行转码和周期性批量传输视频数据来降低功耗。我们已经实现了该系统，并使用一台PDA和一台笔记本电脑进行了多次实验。因此，我们已经确认，我们的系统在PDA上可以延长电池寿命2.8倍，在笔记本电脑上可以延长1.6倍，并且可以以相当小的误差控制电池寿命。

In streaming playback of video, portable wireless devices consume a lot of electric power for video data decoding and wireless communication. Therefore there are demands to control the power consumption so that the battery life can be extended to a desirable playback duration and/or the specified percentage of the battery capacity is left for the other applications. In this research, we have proposed a battery-aware video streaming system to play back for specified duration considering a preference of quality of video specified by each user and the remaining battery amount for portable wireless devices. In the system, power consumption is reduced by using transcoding of video and periodic bulk transfer of video data. We have implemented the system and carried out several experiments using a PDA and a laptop PC. As a result, we have confirmed that our system can extend the battery life up to 2.8 times on the PDA and up to 1.6 times on the laptop PC, and can control the battery life with reasonably small error.