• Journal of KIISE:Computer Systems and Theory
• /
• v.33 no.9
• /
• pp.585-591
• /
• 2006

Generalized Processor Sharing(GPS) model provides instantaneous fair services to currently backlogged sessions. Since this fair service distributes server capacity to backlogged sessions in proportion to their weights, the fairness is only valid between the sessions serviced at the same time. From the long time view, however, this fair service provides different server capacity with one session or another, even if these sessions have the same weights. This paper proposes a cumulative fair service(CFS) model to provide fair server capacity to all sessions in the long time view. This model provides fair service in session Viewpoint because it distributes server capacity in proportion to the weights of sessions. The model and an algorithm referencing that model are analyzed for their properties and performances. Performance evaluations verify that the proposed algorithm provides proportional service capacity to sessions in the long time view.

• The KIPS Transactions:PartA
• /
• v.14A no.7
• /
• pp.451-456
• /
• 2007

In this paper, we regard computer systems as heterogeneous multi-server systems and propose a cumulative fair scheduling scheme that pursues long-term fairness. GPS(generalized processor sharing)-based scheduling algorithms, which are usually employed in single-server systems, distribute available capacity in an instantaneous manner. However, applying them to heterogeneous multi-server systems may cause unfairness, since they may not prevent the accumulation of scheduling delays and the extra capacities are distributed in an instantaneous manner. In our scheme, long-term fairness is pursued by proper distribution of extra capacities while guaranteeing reserved capacities. A reference capacity model to determine the ideal progresses of applications is derived from long-term observations, and the scheduler makes the applications gradually follow the ideal progresses while guaranteeing their reserved capacities. A heuristic scheduling algorithm is proposed and the scheme is examined by simulation.

• 월간 기계설비
• /
• no.9 s.218
• /
• pp.38-39
• /
• 2008

정부 부처에 산재돼 있는 하도급거래정보를 하나로 묶는 불공정하도급거래통합감시망이 구축될 예정이다. 공정거래위원회는 최근 정부 부처에 산재돼 있는 하도급거래정보를 하나로 묶는 '불공정하도급거래통합정보시스템'을 올 11월까지 구축하기로 하고 사업에 착수했다고 밝혔다. 공정위에 따르면 하도급 서면실태조사결과가 누적돼 매년 수만개 업체의 하도급 자료가 축적되고 하도급법 적용 범위가 서비스업종까지 확대돼 적용대상 사업자수가 대폭 늘었지만, 현재의 정보시스템으로는 불공정하도급거래를 체계적으로 감시하는데 한계가 있고, 법위반 혐의를 포착해 조사에 활용하는 사전대응 기능이 미흡하기 때문에 불공정하도급거래 통합 감시망을 구축하게 된 것이다. 불공정하도급거래통합정보시스템이 구축되면 불공정하도급 발생 위험 정보를 신속하게 전파할 수 있고 경보발령 체계 확보로 조기 확산방지 능력을 갖추게 되며 특히 업종, 업체, 법 위반 유형에 따라 체계적인 정보 관리 및 분석이 가능하고 업체에 대한 사건처리의 진행상태도 파악할 수 있게 될 것으로 기대되고 있다.

• Journal of KIISE:Computer Systems and Theory
• /
• v.34 no.5_6
• /
• pp.249-256
• /
• 2007

GPS(generalized processor sharing) is a fair scheduling scheme that guarantees fair distribution of resources in an instantaneous manner, while virtual clock pursues fairness in the sense of long-term. In this paper, we notice that the degree of memorylessness is the key difference of the two schemes, and propose a unified scheduling model that covers the whole spectrum of history-sensitiveness. In this model, each application's resource right is represented in a value called deposit, which is accumulated at a predefined rate and is consumed for services. The unused deposit, representing non-usage history, gives the application more opportunity to be scheduled, hence relatively enhancing its response time. Decay of the deposit means partial erase of the history and, by adjusting the decaying rate, the degree of history-sensitiveness is controlled. In the spectrum, the memoryless end corresponds GPS and the other end with full history corresponds virtual clock. And there exists a tradeoff between average delay and long-term fairness. We examine the properties of the model by analysis and simulation.

• Journal of the Korean Society of Radiology
• /
• v.15 no.6
• /
• pp.803-811
• /
• 2021

In this study, the exposure amount of IASCC test worker was evaluated by applying the process simulation technology. Using DELMIA Version 5, a commercial process simulation code, IASCC test facility, hot cells, and workers were prepared, and IASCC test activities were implemented, and the cumulative exposure of workers passing through the dose-distributed space could be evaluated through user coding. In order to simulate behavior of workers, human manikins with a degree of freedom of 200 or more imitating the human musculoskeletal system were applied. In order to calculate the worker's exposure, the coordinates, start time, and retention period for each posture were extracted by accessing the sub-information of the human manikin task, and the cumulative exposure was calculated by multiplying the spatial dose value by the posture retention time. The spatial dose for the exposure evaluation was calculated using MCNP6 Version 1.0, and the calculated spatial dose was embedded into the process simulation domain. As a result of comparing and analyzing the results of exposure evaluation by process simulation and typical exposure evaluation, the annual exposure to daily test work in the regular entrance was predicted at similar levels, 0.388 mSv/year and 1.334 mSv/year, respectively. Exposure assessment was also performed on special tasks performed in areas with high spatial doses, and tasks with high exposure could be easily identified, and work improvement plans could be derived intuitively through human manikin posture and spatial dose visualization of the tasks.