Wanghong Yuan

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This paper presents <i>GRACE-OS</i>, an energy-efficient soft real-time CPU scheduler for mobile devices that primarily run multimedia applications. The major goal of GRACE-OS is to support application quality of service and save energy. To achieve this goal, GRACE-OS integrates dynamic voltage scaling into soft real-time scheduling and decides how fast to(More)
Mobile devices primarily processing multimedia data need to support multimedia quality with limited battery energy. To address this challenging problem, researchers have introduced adaptation into multiple system layers, ranging from hardware to applications. Given these adaptive layers, a new challenge is how to coordinate them to fully exploit the(More)
In this paper, we introduce an XML-based Hierarchical QoS Markup Language, called HQML, to enhance distributed multimedia applications on the World Wide Web (WWW) with Quality of Service (QoS) capability. The design of HQML is based on two observations: (1) the absence of a systematic QoS specification language, that can be used by distributed multimedia(More)
This article presents the design, implementation, and evaluation of <i>EScheduler</i>, an energy-efficient soft real-time CPU scheduler for multimedia applications running on a mobile device. EScheduler seeks to minimize the total energy consumed by the device while meeting multimedia timing requirements. To achieve this goal, EScheduler integrates(More)
Mobile devices primarily processing multimedia data need to support multimedia quality with limited battery energy. To address this challenging problem, researchers have introduced adaptation into multiple system layers, ranging from hardware to applications. Given these adaptive layers, a new challenge is how to coordinate them to fully exploit the(More)
Mobile systems primarily processing multimedia data are expected to become important platforms for pervasive computing. These systems, however, must satisfy large, dynamic demands of multimedia applications subject to stringent energy, computational, and bandwidth constraints. At the same time, multimedia applications provide the possibility of adaptation,(More)
Battery-powered mobile devices are becoming increasingly important computing platforms, which require low energy consumption while meeting the resource demands of a dynamic application workload. Most proposed dynamic voltage scaling (DVS) algorithms, targeting either best-effort or hard real-time systems, however, cannot be directly applied to such open(More)
In traditional computer systems, security is typically provided in a one-or-nothing manner; the system is either secure or insecure. Such an approach is insufficient for pervasive environments that contain heterogenous devices with varying computing resources. The small, portable handheld devices are often left unsecured due to their limited computing(More)