Jungmee Yun

Design of energy-efficient Set-top Box

Set-top Box (STB) which receives broadcasting signal and delivers it to display device such as TV usually has not low-power mode, standby power mode. On the other side, most consumer electronics have standby power mode. The main reasons come from technical barriers and operational stability and STB normally consumes 80∼90% power of active mode even though turning off the STB. However, most developed countries including Korea are enforcing the regulations which enhance energy efficiency of STB. This paper describes design and development of low-power STB. We want to show the improving direction of overall energy efficiency of parts, system and protocol within STB and prove energy saving expectation.

Hybrid web server: Traffic analysis and prototype

Web servers in small and medium enterprises (SME) consume a significant amount of energy. We consider how a hybrid SME web server based on two co-located platforms (one high performance and high power and the second low performance and low power) can be architected to appear as a single system image to clients. A prototype based on a Dell AMD Athlon x64-based PC and a Sheeva ARM-based plug computer is described and evaluated using the Apache ab benchmark. Using traffic traces from the KETI corporate web server, we show that for the majority of the time a low-performance platform can very likely meet the performance demands (during which time the high-power platform can sleep). We explore prediction of server load using network traffic analysis as a means to achieve a selection (or switching) policy between the two platforms. Using simple prediction methods, we show that we can achieve between 41% to 67% energy savings with minimal performance impact.

Designing stand-by gateway for managing a waste of networked home-device power

The Internet protocols were designed when there were relatively few devices connected to the Internet and these devices were in use most of the time. Studies show many of these computers especially in home have their power management features disabled in order to maintain their network presence and network connections. Past research proposes to use a low power proxy to “stand in” for a computer, allowing it to go to sleep and thus save power while still maintaining its network presence. This paper describes an experimental stand-by gateway that can be used to develop the requirements for such a proxy. With the stand-by gateway, we propose to develop a language to be used by applications to provide the necessary code to the proxy to maintain network connections and presence for a sleeping computer. And we investigate the possibility of putting various components on home gateway to sleep during periods of low traffic activity. Out results show that sleeping is indeed feasible in the home network

Fault diagnosis and recovery scheme for Web server using case-based reasoning

This paper proposes the fault items incurred Web server management and the rules for fault diagnosis and recovery scheme by INBANCA technology. We have defined the fault items which are daemon process fault, server overload, network interface fault, configuration and performance fault and formulated system-level fault diagnosis production rule and service-level fault diagnosis rule by translating expertise into active network for management. Also, an adaptive recovery mechanism for Web server is applied to defining the recovery rules and constructing the case library for case-based Web server fault recovery.

Timed redirection: HTTP request coalescing to reduce energy use of hybrid web servers

Network protocols can be designed to enable a reduction in energy use of data servers. We architect a new HTTP timed redirection response for a GET request to be redirected to another server with a given delay. This redirection response can be used in a hybrid web server to coalesce GET requests and allow a server to periodically sleep. In such a hybrid web server, a small low-power ARM-based Assistant receives all incoming HTTP requests and redirects them to a Pentium-class Master server with a delay calculated to allow the Master to sleep in alternating intervals. There is a growing class of applications that are delay tolerant at short time scales for file downloads. Experimental evaluation of timed redirection shows significant savings for the Master server with added delay for some requests which may be acceptable for certain applications.

Study on Improving Energy-Efficiency of Set-top Box

Set-top Box which receives broadcasting signal and delivers it to display device such as TV usually doesn`t have low-power mode, standby power mode. On the other side, most consumer electronics support standby power mode. The main reasons come from technical barriers and operational stability. Set-top box normally consumes 80~90% power of active mode even though turning off. This is much higher compared to other consumer electronics which consume less than 1W in standby power mode. However, most developed countries including Korea are enforcing the regulations which enhance energy efficiency of set-top box. This paper describes design and development of low-power set-top box. Key technologies are SoC supporting low-power mode, system hardware and software operating in separated power mode, and middleware managing the power with broadcasting system. Finally, we show energy saving expectation through development and proliferation.