本論文研究並設計與實作使用者空間(User Space)動態電源管理框架，目的乃使系統能依據運行於使用者空間之電源管理框架模組設定CPU與周邊裝置的使用功耗，以協助動態地調節系統功耗並達成節能省電之效果。本論文設計的使用者空間動態電源管理框架其組成元件包含：管理員(Administrator)、組態器模組(Profiler)、策略管理模組(Policy Manager)、電源管理模組(Power Manager)、通報模組(Informer)、DPM_Driver核心模組等元件。除DPM_Driver核心模組之外，各模組皆運作或執行於使用者空間。
本論文設計之使用者空間動態電源管理框架可依據使用者與應用程式需求有效地動態調整系統功耗；動態電源管理元件與電源感知應用程式之間能有效率地交換電源需求與供應相關資訊。相較實現於核心空間(Kernel Space)之電源管理機制，使用者空間軟體可提供開發人員與使用者更大的彈性。軟體框架式的設計可方便開發人員依需求置換或擴增動態電源管理功能。此使用者空間動態電源管理框架亦包含一動態電源管理函式庫，使動態電源管理模組與應用程式之間可建構良好的溝通機制；策略管理模組能藉此分析應用程式期望之供電需求，以盡可能少的系統功耗滿足應用程式所需；應用程式可依通報模組提供之系統功耗與供電資訊調整運作行為，降低自身工作負載。在這相輔相成的關係之下，達到有效節能之目的。
為驗證本論文設計之使用者空間動態電源管理框架之有效性，本論文以嵌入式Linux作業系統為軟體執行環境，使用Creator PreSOC/PXA270為硬體平台進行實作。實驗結果顯示本論文設計並實作之使用者空間動態電源管理機制可減少約8.5%的CPU電流消耗；若配合應用程式執行時之需求動態地調整TFT-LCD亮度，可減少約14.2%的TFT-LCD電流消耗。

This thesis presents a study on the design and implementation of a user-space Dynamic Power Management (DPM) framework. The goal is to enable the system to adjust, based on the setting by the power management modules running in user space, the energy consumption of CPU and peripheral devices in order to help dynamically manage system power consumption as well as achieve energy saving. The user-space DPM framework designed in this thesis is composed of Administrator, Profiler, Policy Manager, Power Manager, Informer and a DPM_Driver kernel module. Except the DPM_Driver kernel module, all the power management modules are designed to execute in user space.
The user-space DPM framework is capable of dynamically manage voltage or current consumption of the system based on application requirement or user requests. Compared to the DPM functionality commonly implemented in kernel space of the system, it can provide more flexibility. The construct of framework in addition allows selective change and/or desired extention to the functionality. A DPM function library, namely DPM_Library, is provided to help application to interact with DPM modules as well as help develop power-aware applications. The DPM modules therefore can analyze power requirements of applications while applications are able to obtain the power condition of the system and adjust work load accordingly, thereby achieve the goals of power management and energy saving from both direction.
To demonstrate the proposed framework, an example version was implemented in the environment of Embedded Linux on Creator PreSOC/PXA270 platform for applications. From the experiment results, it can be observed that the user-space DPM framework can reduce about 8.5% current consumption of CPU and the saving on current consumption of TFT-LCD can avhieve 14.2%.

[1] Aaron Carroll, Gernot Heiser, “An Analysis of Power Consumption in a Smartphone”, USENIXATC'10 Proceedings of the USENIX conference on USENIX annual technical conference, 2010.
[2] ACPI Component Architecture - User Guide and Programmer Reference.
[3] Advanced Configuration and Power Interface , http://www.acpi.info/.
[4] Advanced Configuration and Power Interface Specification
[5] Android Developer, http://developer.android.com/guide/basics/what-is-android.html.
[6] Bishop Brock, Karthick Rajamani, “Dynamic Power Management for Embedded System”, IEEE International SOC Conference, Pages 416-419, September 2003.
[7] Chandrakasan, S. Sheng, R. W. Brodersen, “Low-power CMOS digital design”, IEEE Journal of Solid-State Circuits, Volume 27, Pages 473–484, April, 1992.
[8] Changjiu Xian, Yung-Hsiang Lu, Zhiyuan Li, “A Programming Environment with Runtime Energy Characterization for Energy-Aware Applications”, ISLPED’07, August 27–29, 2007.
[9] Chong-Min Kyung, Sung joo Yoo, “Energy-Aware System Design”, 2011.
[10] ENERGY STAR* Version 5.0 System Implementation Whitepaper.
[11] Hojun Shim, “Low-Power LCD Display Systems”, ISLPED’02, August 12-14, 2002.
[12] Inseok Choi, Hojun Shim, Naehyuck Chang, “Low-Power Color TFT LCD Display for Hand-Held Embedded Systems”, ISLPED '02 Proceedings of the international symposium on Low power electronics and design, 2002.
[13] Jason Flinn, M. Satyanarayanan, “Managing Battery Lifetime with Energy-Aware Adaptation”, ACM Transactions on Computer Systems, Vol. 22, No. 2, Pages 137–179, May 2004.
[14] Krzysztof Cwalina, Brad Abrams , Framework Design Guidelines, 2008 .
[15] Less Watts, http://www.lesswatts.org/.
[16] Liang-Bi Chen, Yen-Ling Chen, Ing-Jer Huang, “A Real-Time Power Analysis Platform for Energy-aware Embedded System Development”, Journal of Information Science and Engineering 27, 1165-1182, 2011.
[17] Luca Benini, Giovanni De Micheli, “System-Level Power Optimization: Techniques and Tools”, ACM Transactions on Design Automation of Electronic Systems, Vol. 5, No. 2, Pages 115–192, April 2000.
[18] Mohamed Fayad, Douglas C. Schmidt, “Object-oriented application frameworks”, Communications of the ACM CACM Homepage archive Volume 40 Issue 10, Oct. 1997.
[19] Mohamed Shalan, Dina El-Sissy, “Online Power Management using DVFS for
RTOS”, Design and Test Workshop (IDT),4th International, 2009.
[20] MSDN Magazine, http://msdn.microsoft.com/zh-tw/magazine/cc163386.aspx.
[21] National Instruments, http://sine.ni.com/nips/cds/view/p/lang/zht/nid/203223.
[22] Priya N. Vaidya, Moinul H. Khan, Bryan Morgan, Premanand Sakarda, “System Level Adaptive Framework For Power and Performance Scaling on INTEL® PXA27X Processor”, International Conference about Space Solar Power , 2005.
[23] PXA27x Processor Family Developer's Manual.
[24] Sanjay Udani, Jonathan M. Smith, “Power Management in Mobile Computing (A Survey)”, Distributed Systems Laboratory Department of Computer Information Science University of Pennsylvania, 1996.
[25] The ACPI Component Architecture Project, https://www.acpica.org/.
[26] Venkatesh Pallipadi, Alexey Starikovskiy, “The Ondemand Governor”, Proceedings of the Linux Symposium, July 19th–22nd, 2006.
[27] Wanghong Yuan, Klara Nahrstedt, “Energy-Efficient Soft Real-Time CPU Scheduling for Mobile Multimedia Systems”, SOSP, October 19–22, 2003.
[28] Wikipedia, “Advanced Configuration and Power Interface”, http://en.wikipedia.org/wiki/Advanced_Configuration_and_Power_Interface.
[29] Wikipedia, “Advanced Power Management”, http://en.wikipedia.org/wiki/Advanced_Power_Management.
[30] Wikipedia,“Dynamic frequency scaling”, http://en.wikipedia.org/wiki/Dynamic_frequency_scaling.
[31] Wikipedia,“Dynamic voltage scaling”, http://en.wikipedia.org/wiki/Dynamic_voltage_scaling.
[32] Wikipedia, “Object reques tbroker”, http://en.wikipedia.org/wiki/Object_request_broker.
[33] Wikipedia, “Software framework”, http://en.wikipedia.org/wiki/Software_framework.
[34] Wikipedia, “SpeedStep”, http://en.wikipedia.org/wiki/SpeedStep.
[35] Wikipedia,“Voltage and frequency scaling”, http://en.wikipedia.org/wiki/Voltage_and_frequency_scaling.
[36] Windows Device Center, http://msdn.microsoft.com/en-us/library/windows/hardware/ff540493%28v=vs.85%29.aspx.
[37] Yunsi Fei, Lin Zhong, Niraj K. Jha “An Energy-Aware Framework for Dynamic Software Management in Mobile Computing Systems”, ACM Transactions on Embedded Computing Systems, Vol. 7, No. 3, Article 27, Publication date, April 2008.
[38] Yu Xiao, Rijubrata Bhaumik, Zhirong Yang, Matti Siekkinen, Petri Savolainen, Antti Yla-Jaaski, “A System-level Model for Runtime Power Estimation on Mobile Devices”, IEEE/ACM International Conference on Green Computing and Communications & IEEE/ACM International Conference on Cyber, Physical and Social Computing, 2010.
[39] Xiaotao Liu, Prashant Shenoy, Mark D. Corner, “Chameleon: Application-Level Power Management”, IEEE TRANSACTIONS ON MOBILE COMPUTING, VOL. 7, NO. 8, August 2008.
[40] 柯昱仰, “微核心作業系統動態電源管理之設計與實作”, 電機工程學系碩士論文, 國立成功大學, 2010.
[41] 新華電腦公司, http://www.microtime.com.tw/product/PreSOCes/PreSOCes.htm.