• Journal of KIISE:Computer Systems and Theory
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• v.28 no.11
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• pp.573-580
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• 2001

When tasks access shared resources in real-time systems, the unbounded priority inversion may occur. In such cases it is impossible to guarantee the schedulability of real-time tasks. Several resource access protocols have been proposed to bound the duration of priority inversion and sufficient conditions are given to guarantee the schedulability of periodic task set. In this paper, we show an improved sufficient condition for schedulability when the dynamic priority ceiling protocol is used. Our approach exploits the fact that a lower priority task can continue to execute as far as the higher priority tasks do not miss their deadlines. This permitting execution time of the higher priority tasks for a lower priority task can be excluded from the worst-case blocking time of the higher priority tasks. Since the worst-case blocking time of tasks can be reduced, the sufficient condition for schedulability of dynamic priority ceiling protocol becomes further tight.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.82-84
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• 2001

Real-Time Linux는 기존의 Linux에 실시간 기능을 추가한 것으로서, 태스크 스케줄링 방법은 우선순위 기반의 스케줄링 방법을 사용한다. 그러나, 태스크의 개수가 많아지면 가장 높은 우선순위의 태스크를 찾는데 걸리는 시간이 태스크 개수에 비례해서 많이 걸린다. 이러한 이유로 태스크의 개수가 제한적일 수밖에 없다. 본 논문에서는 우선순위별로 서로 다른 목록을 유지하고, Bit Masking 기법을 사용함으로써 가장 높은 우선순위 태스크를 선택하는데 걸리는 시간을 상수시간으로 줄이고 각 태스크들의 시그널을 처리하는 부분을 좀더 효율적으로 처리하도록 함으로써 Real-Time Linux의 실시간 스케줄링 기능을 개선하였다.

• The Journal of the Korea Contents Association
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• v.15 no.1
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• pp.264-275
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• 2015

While the method of prioritization has been practicing in the community needs-based programs to improve the effectiveness and efficiency of community health planning, it has not been systematically used. This study aims to suggest more sophisticated method of prioritizing. Based on the analysis of 81 community health plans which adopt prioritizing method, this study tried to examine their methods and criteria and evaluate their adequacy. In the prioritization process, projects themselves, rather than health problems, were commonly adopted for the subject of the analysis. The most used was the Basic priority rating, followed by the Prioritization matrix. Looking at the size of health problem among the prioritization criteria, the prevalence for chronic diseases and the proportion of people with health problems for health behaviors, mainly were used as indicators. Along with the size of health problem, other factors such as the degree of seriousness of health problem, and the effectiveness of intervention have been used as the criteria of prioritizing, not fully supported by objective data base and the clear standard of scoring. In the prioritization, the analysis need to be limited only to health problems, and the scoring criteria for each health problem area be presented.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.6
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• pp.1065-1071
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• 2009

Satellite application services can be divided into realtime services like voice communications and non-real time services like traditional data communications. To support both types of services on the same On-Board Switching(OBS), a scheduler which depends on their service classes is required. A fixed priority scheduling policy has a starvation problem. In this paper we propose a scheduling scheme based on premium and age. Premium is a fixed value which is given to a certain class of services. Age is another parameter of the scheduling policy and it will be increased by one for every scheduling cycle. The scheme we propose chooses a packet which has the largest sum of its age and premium. Simulation results indicate that the proposed approach shows better performance in both average cell delay and std-dev of cell delay for the lower class of service. There is no staying in infinite starvation state.

• Journal of the Korean Geographical Society
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• v.43 no.6
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• pp.961-980
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• 2008

It is usual to prioritize the blocks to rearrange residential environment by the responsible officer's intuition or a few specialist's experienced knowledge. The aim of this research was to evaluate rebuilding priority in the context of spatially weighted framework integrating resident's view. The spatial weighting for the variables related to evaluation of dwelling environment was derived from AHP (Analytic Hierarchy Process) approach through the analysis of resident's view. An empirical study for a case study site has been conducted to confirm the validity for the spatial weighting. The spatial weighting has frequently influenced in changing the rebuilding priority and was identified as the important predictor for the improvement sites of dwelling environment. The spatially weighted analysis made it possible to identify area-wide patterns of rebuilding priority area subject to many different type of thematic variables, which cannot be acquired by traditional field sampling. The spatially weighting derived by integrating various formats of spatial data into a comprehensive GIS database in particular, was ideally suited to displaying the objective distribution patterns for rebuilding priority. The result of this study would play a crucial role in dealing with public complaints for rebuilding priority since it could provide objective evidences in accordance with spatial weighting.

• The Journal of the Korea Contents Association
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• v.20 no.6
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• pp.342-353
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• 2020

The purpose of this study is to identify priority factors for improving service quality of cosmetic stores in drug stores(DRS) and department stores(DES) and to provide basic data for improving service quality of cosmetic stores by analyzing the service quality based on the Kano model and the Potential Customer Satisfaction Improvement (PCSI) Index. As a result, most items of quality factors of cosmetic stores in both stores were evaluated as attractive quality factors. As a result of PCSI Index comparison, the quality factors of 'Reliability', 'Responsiveness', and 'Empathy' items for DRS and 'Empathy' and 'Reliability' items for DES had higher priority for improvement. That is, if these factors are improved, there is a high potential to improve customer satisfaction. Through this study, practical implications were provided by identifying service quality factor classification and priorities for customer satisfaction improvement of DRS and DES. This is expected to contribute to the guidelines for improving customer satisfaction in the future.

• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.6
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• pp.47-57
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• 2009

Existing bridges are classified into 4 retrofit groups using the current preliminary screening method, considering key terms such as seismicity, vulnerability and social impact effect. However, some irrationality was found when the current method was applied to 442 existing bridges. As a result, it was determined that quantification and a more detailed classification of seismicity were required. The estimation of the vulnerability of box girder bridges having a long span length should be improved, as this showed a tendency to underestimate. It was also necessary to increase the level of social impact effect to that of vulnerability. In this study, an improved preliminary screening method has been proposed on the basis of the estimation results of existing bridges.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.2
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• pp.198-206
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• 2013

This paper presents the improvement of tracking performance using fuzzy inference system based task prioritizations for multi-function radars. The presented technique calculates elemental priorities using track information of a target and obtain the total priority from fuzzy inference system of each fuzzy set's membership function. In this paper, we proposed the task prioritization algorithms based on fuzzy inference system, and evaluated the tracking performance on multi-function radar scenario using it. As a result, we confirmed that excellent performance could be achieved when using the proposed algorithm.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.817-821
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• 2010

댐 하류하천 정비사업을 계획함에 있어 사업의 투자우선순위 결정시 의사결정의 어려움에 직면할 수 있다. 본 연구는 이러한 어려움을 지원하고자 다기준의사결정기법 가운데 하나인 PROMETHEE를 활용하여 투자우선순위를 제시하였다. 댐 하류하천 19개에 대한 투자우선순위를 검토하기 위한 평가기준으로서 용수공급량 회복, 발전량 회복, 계획방류량 회복, 치수경제성 분석, 환경생태기능 개선, 잠재적 홍수피해도, 홍수방어능력 취약도를 고려하였고, PROMETHEE 시행 결과 평림댐 하류하천에 대한 정비사업이 가장 시급한 것으로 분석되었다. 본 연구에서 제시한 19개 댐 하류하천에 대한 투자우선순위 결과는 향후 댐 하류하천 정비사업 계획의 기초자료가 될 수 있을 것으로 판단된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.234-234
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• 2021

국내 기반시설의 대부분은 1970년대 경제성장기에 건설되어 사용연수가 30년 이상 경과하였고 급격한 고령화가 진행 중이다. 1990년대 성수대교와 삼풍백화점의 붕괴는 시설물 유지관리의 중요성에 대한 전국민적 관심을 집중시켰고, 이에 정부는 1995년 「시설물의 안전관리에 관한 특별법」 제정을 시작으로 현재까지 다양한 정책 및 기준을 수립해왔다. 일반적으로 안전점검 및 정밀안전진단 등을 수행하여 시설물의 안전등급을 평가하고 결함에 대한 보수·보강을 실시하여 시설물을 유지·관리하고 있다. 그러나 유지관리 예산은 한정적이기 때문에 모든 결함에 대한 보수·보강 사업을 실시할 수 없는 실정이다. 이에 보수·보강 조치의 우선순위를 선정하는 것이 필요하며, 관련 법령 세부지침에는 부재의 중요도, 결함의 심각성, 경제성을 고려한 우선순위지수(PI, Priority Index)를 제시하고 있다. 이 식은 전문가의 주관적인 판단에 의해 영향도를 50~100%범위 안에서 조정할 수 있으며, 일부 특정 부재는 동일한 가중치가 설정되어 있다. 또한 결정적으로 보수보강을 통한 효과를 효율적으로 고려하지 못하고, 대부분 경제성에 의해 우선순위가 결정되는 한계점이 발생한다. 따라서, 본 연구에서는 몇 가지 사례분석을 통해 현재 우선순위지수에 대한 문제점을 고찰하고 이를 개선할 수 있는 우선순위 산정식(PI)을 제시하였다. 과거 유지관리 시행 초기에는 보수보강 사례가 부족하였지만 현재는 수십년간의 축적된 자료를 바탕으로 제시된 산정식을 충분히 활용할 수 있을 것으로 판단된다. 향후 보수보강 효과를 정량화하는 방법에 대한 추가적인 연구가 수행된다면 더욱 경제적인 측면에서 우선순위를 산정할 수 있을 것이며 노후화된 기반시설 유지관리방안에 효과적으로 사용될 것으로 기대된다.