Browsing by Author "King, Chung-Ta"

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A Wireless Human Motion Capturing System for Home Rehabilitation
(2009)
Tseng, Yu-Chee
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Wu, Chin-Hao
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Wu, Fang-Jing
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Huang, Chi-Fu
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King, Chung-Ta
Following the trend of miniature intelligent sensing, wearing small, integrated wireless sensor nodes, such as one with accelerometers and compasses, to capture human body motions may have many applications in medical care and computer animation. In this paper, we demonstrate the use of intelligent sensors to capture human motions for home rehabilitation. We design a game to help a patient to conduct his/her rehabilitation program. For each exercise, the patient is instructed to wear sensors on specified movable body parts. The system will then estimate the quality of the movements and give scores as if it is advised by a therapist. In this way, patients will no longer feel painful and boring as that in traditional rehabilitation, which is typically done in hospitals.
Characterizing Display QoS Based on Frame Dropping for Power Management of Interactive Applications on Smartphones
(2018-01-01)
Ho, Kuan-Ting
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King, Chung-Ta
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Das, Bhaskar
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Chang, Yung-Ju
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資訊工程學系
User-centric power management in smartphones aims to conserve power without affecting user's perceived quality of experience. Most existing works focus on periodically updated applications such as games and video players and use a fixed frame rate, measured in frame per second (FPS), as the metric to quantify the display quality of service (QoS). The idea is to adjust the CPU/GPU frequency just enough to maintain the frame rate at a user satisfactory level. However, when applied to aperiodically-updated interactive applications, e.g. Facebook or Instagram, that draw the frame buffer at a varying rate in response to user inputs, such a power management strategy becomes too conservative. Based on real user experiments, we observe that users can tolerate a certain percentage of frame drops when running aperiodically updated applications without affecting their perceived display quality. Hence, we introduce a new metric to characterize display quality of service, called the frame drawn ratio (FDR), and propose a new CPU/GPU frequency governor based on the FDR metric. The experiments by real users show that the proposed governor can conserve 17.2% power in average when compared to the default governor, while maintaining the same or even better QoE rating.
SCQ: Stage-based, Context-aware, QoE-driven Power Optimization for Interactive Applications on Mobile Devices
(2019-01-01)
Ho, Chi-Kai
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King, Chung-Ta
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Chang, Yung-Ju
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資訊工程學系
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Department of Computer Science
Mobile devices such as smartphones and tablets have become our daily necessities. People spent a lot of time using their smartphones, especially on interactive applications such as social networks, web browsing, and games. To conserve power consumption of such applications becomes ultimately important. Prior works try to save power by balancing performance and workload. These approaches are not comprehensive because they do not take user experience (or Quality of Experience, QoE) into account. Overlooking this factor may turn out to subscribe an excessive performance that the user cannot even perceive, leading to a waste of power. Users' QoE is affected by many factors, including their contexts and the stage of the application. Estimating the QoE requirements for different situations is not only complicated but also crucial. In this paper, we attack this complex problem by first predicting the execution stages of the interactive applications and then applying a stage-based, context-aware, QoE-driven governor (SCQ) to adjust the CPU frequency. Experimental results show that our approach can save 23% more power than the default governor without affecting users' QoE.