• Journal of Electrical Engineering and Technology
• /
• 제4권1호
• /
• pp.43-48
• /
• 2009

The purpose of the this paper is to make decision of the maintenance priority of power distribution system using Time-Varying Failure Rate(TVFR) with interruption cost. This paper emphasizes the practical use of the reliability indices and interruption cost. To make a decision of maintenance priority on power distribution system equipment, the quantification of the reliability level should be represented as a cost. In this paper, the TVFR of power distribution system equipment applied in this paper utilizes analytic method to use the historical data of KEPCO. From this result, the sensitivity analysis on TVFR of equipment was done for the priority, which represents that high priority of the equipment has more effect on system reliability, such as SAIDI or SAIFI, than other equipment. By this priority, the investment plan is established. In this result, customer interruption cost(CIC) could be extracted, and CIC is used as weighting factor to consider a importance of customer. After that, the result calculated the proposal method in this paper is compared with other priority method, such as lifetime, failure rate or only sensitivity.

• 대한산업공학회지
• /
• 제24권4호
• /
• pp.519-528
• /
• 1998

This paper examines the effect of storage location configurations on dual command cycle times for the efficient operation of automated storage/retrieval systems. We use a contour line approach to determine storage location configurations. We present a contour line configuration generating scheme and a location indexing scheme. Given a contour line configuration, the location indexing scheme provides a unique priority to each location. The location priority is then used for determining the storage location of an incoming load. To investigate the effect of alternative contour line configurations on dual command cycle times, we perform a series of experiments under various storage policies.

• 한국환경복원기술학회지
• /
• 제8권3호
• /
• pp.53-66
• /
• 2005

The objective of this study is the classification of priority areas for the implementation of green roof by evaluating environmental deterioration in Seoul. Non-permeable pavement, air pollution, habitual floods, energy use, heat island and green space are considered in this assessment indicators. The expert questionnaire survey was conducted in order to determine the most important indicators. These indicators were then, thoroughly evaluated. As a result, high priority areas for the implementation of green roof were deduced in the following order of the districts : Jung, Sungdong, Jungrang, Youngdungpo, Jongro and Kangnam. The highest priority areas were determined to be crowded business-commercial areas. Low priority areas are analyzed in the following order of the districts : Kwanak, Nowon, Seocho and Dobong. The result of this study can be utilized for environmental planning and decision of related policies. Additionally, it can be promoted that awareness of implementing green roof of citizens, policy makers and building owners and effect of green networking between inside and outside Seoul can be increased.

• 산업경영시스템학회지
• /
• 제46권2호
• /
• pp.57-71
• /
• 2023

In this study, we analyze a finite-buffer M/G/1 queueing model with randomized pushout space priority and nonpreemptive time priority. Space and time priority queueing models have been extensively studied to analyze the performance of communication systems serving different types of traffic simultaneously: one type is sensitive to packet delay, and the other is sensitive to packet loss. However, these models have limitations. Some models assume that packet transmission times follow exponential distributions, which is not always realistic. Other models use general distributions for packet transmission times, but their space priority rules are too rigid, making it difficult to fine-tune service performance for different types of traffic. Our proposed model addresses these limitations and is more suitable for analyzing communication systems that handle different types of traffic with general packet length distributions. For the proposed queueing model, we first derive the distribution of the number of packets in the system when the transmission of each packet is completed, and we then obtain packet loss probabilities and the expected number of packets for each type of traffic. We also present a numerical example to explore the effect of a system parameter, the pushout probability, on system performance for different packet transmission time distributions.

• 한국농공학회논문집
• /
• 제59권3호
• /
• pp.51-62
• /
• 2017

Since living environment has improved, waterfront space using and clear water demand have increased. Ministry of Environment (ME) designated polluted reservoir (worse than 4th grade) as a priority management reservoir to improve water quality (better than 3rd grade) accordingly. Minstry of Agriculture, Food and Rural Affairs (MAFRA) aims reservoir water quality 4th not 3rd grade. And water quality of agricultural reservoirs was not a great interest. For this reason, there are very few water quality monitoring data. However after designating as a priority management reservoir, reservoir manager should start water quality and flow monitoring of reservoirs and inflow streams. This process makes it possible setting complex model to accurate prediction of reservoir water quality and volume. Mulwang reservoir designated as a priority management reservoir in September 2014. In this study, BASINS/WinHSPF and EFDC-WASP were used to predict effect of water quality improvement countermeasures in Mulwang reservoir. To improve water quality of Mulwang reservoir, Siheung-si and Korea Rural Community Corporation (KRCC) established water quality improvement countermeasures. However result of simulation adapting these countermeasures cannot achieve 3rd grade. So 4 additional scenarios were adapted and the result satisfied 3rd grade. This study could help to establish water quality improvement countermeasure by using complex modeling.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2003년도 ICCAS
• /
• pp.687-690
• /
• 2003

This paper presents the development of Programmable Logic Controller (PLC) and network to design the redundant control system in order to control the high priority process. The industrial process that cannot be shutdown or the effect of the shutting down takes abundantly damage. In this article, we say that the high priority process. The redundant systems are designed for controlling the high priority process that the control system must have many controllers to instead the main controller when it has some error. This paper we designed the redundancy control system by the advantage of the high-speed communication on the PLC’s network. The temperature control system and the traffic light control system used as the case study. Each example processes consist of two sets of controller. Our scheme we can increase the reliability prevents process down time and reduces the cost of opportunity to loss also.

• 한국산업융합학회 논문집
• /
• 제9권4호
• /
• pp.285-291
• /
• 2006

A traffic accident is occurred by unbalance of reciprocal action of driver, vehicle and road conditions. To prevent the traffic accident, rapid and perfect road improvement is needed. But most of road improvement plans have insufficient budget. So decision maker has to determine the priority to invest. A model in this study, analyzing the effect of road conditions to the traffic accident, helps to decide the priority in road improvement. This study considered five danger indices ; 1) traffic volume, 2) speed variance, 3) vehicle mixing rate, 4) curved line radius, and 5) difference between design speed and running speed. Danger rate composed by five indices can be a scale of priority of improvement. The model in this study didn't consider all of factors about traffic accident. But this study can propose the methodology for traffic safety policy. For deriving the model, this study used data from highways in Korea and United States. Therefore the model has to apply the highways only.

• 한국멀티미디어학회논문지
• /
• 제10권12호
• /
• pp.1622-1631
• /
• 2007

To realize the wireless packet scheduler which efficiently considers both the effect of adaptive modulation and coding (AMC) scheme due to variable wireless communication channel information from physical layer and the QoS differentiation of multimedia services from internet protocol (IP) layer, this paper proposes a new downlink AMC-based priority queuing (APQ) scheduler which combines AMC scheme and service priority method in multimedia services at the same time. The result of numerical analysis shows that the proposed APQ algorithm plays a role in increasing the number of services satisfying the mean waiting time requirements per each service in multimedia services because the APQ scheme allows the mean waiting time of each service to be reduced much more than existing packet scheduler having only user selection processor.

• 국제학술발표논문집
• /
• The 6th International Conference on Construction Engineering and Project Management
• /
• pp.687-688
• /
• 2015

The objective of identifying the cause of inconsistency in determining priority of educational facility maintenance, any related factors were thoroughly identified and tested, to see if it has any effect on decision-making process in resource allocation for educational facilities. On the assumption that 'the more there are to be repaired/maintained and deferred, the higher the relevant cost will be, this will lead to a significant social loss. Accordingly, this study established a framework of determining resource allocation priority based on deferred maintenance and its related expenses. For doing so, it was required to determine relative ranking in terms of resource allocation within a pre-assigned school district, in consideration of the criticality of each deferred maintenance attribute/variable.

• 한국정보과학회논문지:데이타베이스
• /
• 제29권1호
• /
• pp.72-78
• /
• 2002

거리조인은 R-트리를 사용하여 두 공간 데이터 집합 사이의 데이터쌍을 거리 상 가까운 순으로 검색하는 공간조인이다. 거리조인은 R-트리를 하향식으로 순회하면서 생성되는 노드쌍들을 거리값 순으로 우선순위 큐에 저장한다. 본 논문에서는 거리조인 처리시 우선순위 큐 안에서 동점자 노드쌍들의 우선 순위 정책이 알고리즘의 성능을 많이 좌우할 수 있음을 보여주고, 이를 위한 최적화된 2차 우선 순위 기법을 제안한다. 실험을 통하여, 제안한 기법이 다른 기법에 비하여 항상 좋은 성능을 나타냄을 보여준다.