• 한국경영과학회지
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• 제27권2호
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• pp.33-49
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• 2002

CBM (Condition-Based Maintenance) has increasingly drawn attention in industry because of its many benefits. CBM Problem Is characterized as a state-dependent scheduling model that demands simultaneous maintenance actions, each for an attribute that influences on machine condition. This problem is very hard to solve within conventional Markov decision process framework. In this paper, we present an intelligent machine maintenance scheduler, for which a new incremental decision tree learning method as evolutionary system identification model and shortest path problem as schedule generation model are developed. Although our approach does not guarantee an optimal scheduling policy in mathematical viewpoint, we verified through simulation based experiment that the intelligent scheduler is capable of providing good scheduling policy that can be used in practice.

• 산업공학
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• 제23권4호
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• pp.327-336
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• 2010

We consider a supply chain consisting of a make-to-order manufacturer and N component suppliers and study the impacts of the number of suppliers on component inventory management. The manufacturer has full information and continuously observes the state of both component inventory level and customer backorders. Based on this information, the manufacturer determines whether or not to place a component purchasing order to a supplier among N suppliers even though some orders are in process by other suppliers. The goal of this paper is to numerically identify the manufacturer's purchasing policy which minimizes the total supply chain cost and the best choice of N. Our model contributes to the current literature in that the problem of simultaneously considering multiple outstanding orders and incorporating order setup cost into the model has not been covered yet. From numerical experiment, we investigate how much the policy with N suppliers can contribute to reducing the supply cost compared to the policy with a single supplier.

• 한국컴퓨터정보학회논문지
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• 제23권4호
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• pp.1-8
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• 2018

In this paper, we propose an adaptive partition cache replacement policy and evaluate the performance of our scheme using various monitoring ratios to help lifetime extension of non-volatile main memory systems without performance degradation. The proposal combines conventional LRU (Least Recently Used) replacement policy and Early Eviction Zone (E2Z), which considers a dirty bit as well as LRU bits to select a candidate block. In particular, this paper shows the performance of non-volatile memory using various monitoring ratios and determines optimized monitoring ratio and partition size of E2Z for reducing the number of writebacks using cache hit counter logic and hit predictor. In the experiment evaluation, we showed that 1:128 combination provided the best results of writebacks and runtime, in terms of performance and complexity trade-off relation, and our proposal yielded up to 42% reduction of writebacks, compared with others.

• 로봇학회논문지
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• 제17권1호
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• pp.58-67
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• 2022

In this paper, we propose an approach resolving inaccuracy of the low-cost redundant manipulator workspace with low encoder and low stiffness. When the manipulators are manufactured with low-cost encoders and low-cost links, the robots can run into workspace inaccuracy issues. Furthermore, trajectory generation based on conventional forward/inverse kinematics without taking into account inaccuracy issues will introduce the risk of end-effector fluctuations. Hence, we propose an optimization for the trajectory generation method based on the DDPG (Deep Deterministic Policy Gradient) algorithm for the low-cost redundant manipulators reaching the target position in Euclidean space. We designed the DDPG algorithm minimizing the distance along with the jacobian condition number. The training environment is selected with an error rate of randomly generated joint spaces in a simulator that implemented real-world physics, the test environment is a real robotic experiment and demonstrated our approach.

• 보건행정학회지
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• 제22권4호
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• pp.467-496
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• 2012

Public participation in the decision making for scarce health resources is important because health policy requires trust based consensus, which can be achieved by public's understanding and involvement of related policies. In the past, opportunities for interaction between health policy decision makers and lay public were rare in Korea. As political impulses towards public participation in health policy have increased, a few of deliberation methods were attempted. However, there is little research, reporting such cases with a critical examination of relevant theories and previous studies. We first critically review the literature on public participation within theories of democracy, governance, and empowerment. Next, we report a case of a citizen council experiment, which was held to examine public's preferences among different benefit options regarding new drugs and medical technologies. Specifically, in an one-day long citizen council with a total of 28 lay public, twelve questions of whether a drug or a technology should be included in the benefit package of health insurance were asked. Pre- and post-surveys investigated participants' perception of public engagement in health policy. Although it was experimental, the citizen council ensured that lay public could be careful enough to rationally compare the costs and benefits of different options and collectively make decisions. Further, results from pre- and post-survey showed a strong willingness of members to be involved in health care decision making. In the conclusion, we emphasize that better theories and methods need to be developed for more cases of citizen participation in health care policy and management.

• 한국기술혁신학회:학술대회논문집
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• 한국기술혁신학회 2015년도 춘계 학술대회 논문집
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• pp.105-112
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• 2015

• 한국수소및신에너지학회논문집
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• 제33권6호
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• pp.674-683
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• 2022

In this study, we examined the case of Fukushima Hydrogen Research Field (FH2R) Namie hydrogen town. We found that the case has three aspects of socio-technical experiment: a living-scale test-bed of hydrogen technologies, activities for enhancing social acceptability, and a designed module for policy transfer to diffuse. This study aims to provide a benchmark for planning a green hydrogen city in near future.

• STI Policy Review
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• 제3권1호
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• pp.96-116
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• 2012

The establishment of Institut Pasteur Korea (IP-K) has been an intercultural experiment, which transplanted a French research organization with many foreign researchers into Korea to grow a new institution as a long-term collaboration. The Mission of the newly founded institute has been to develop more effective ways of generating value with basic life science research in the face of a world-wide Pharma crisis. The challenges have been i.) to invent new technologies and approaches in drug discovery, ii.) to convince the Korean stakeholders of their inherent value, iii.) to induce Pharma industry to adopt the new technologies and iv.) to create a context in the Korean R&D landscape where the new institute could contribute tangible benefits. If Institut Pasteur Korea has succeeded in all counts, then due to a somewhat skewed and unlikely set of cultural complementarities between Korea and France. The abstract and conceptual French approach was matched by Korean pragmatism, linearity and relentless improvement towards the defined development goal. IP-K has become an example for innovation made in Korea, which is now re-imported into Europe. As the project could arguably not have succeeded in either partner county alone, it highlights the benefits of longterm, in depth international collaborations.

• 한국사회정책
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• 제23권1호
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• pp.25-59
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• 2016

본고는 1998년 서울특별시주택조례로 최저주거기준을 설정하였다는 사실을 활용하여 최저주거기준의 정책 효과를 분석한다. 1998년 최저주거기준은 서울시에서만 설정하였으며 서울시를 제외한 전국의 다른 지역에서는 설정하지 않았으므로, 이로 인해 일종의 준실험 상황이 설정되었다고 할 수 있다. 1995년과 2000년 사이 최저주거기준 미달가구수의 감소를 당시 최저주거기준이 설정되었던 서울시와 그렇지 않았던 타 지역을 서로 비교하는 이중차분법을 적용함으로써, 최저주거기준의 정책 효과를 식별하였다. 이중차분법 적용을 위한 가정 충족 여부를 검토한 후, 경기도를 비교집단으로 설정하여 구한 '일대일비교를 이용한 이중차분법 추정치'와 타 광역시도 전체를 비교집단으로 설정하여 계산한 '회귀모형을 이용한 이중차분법 추정치'를 각각 도출하였다. 먼저 일대일비교를 이용한 이중차분법 추정 결과 최저주거기준의 설정은 216,638가구만큼 최저주거기준 미달가구수를 감소시킨 것으로 나타났다. 다음으로 회귀모형을 이용한 이중차분법 추정 결과 최저주거기준의 설정은 325,149가구만큼 최저주거기준 미달가구수를 감소시킨 것으로 나타났으며, 이는 0.1% 유의수준에서 통계적으로 유의하였다. 또한 일대일비교를 이용한 이중차분법 추정치는 회귀모형을 이용한 이중차분법 추정치의 95% 신뢰구간에 속하였다. 따라서 최저주거기준의 설정은 최저주거기준 미달가구수의 감소라는 정책 목표를 달성하는 데 상당한 기여를 한 것으로 판단된다.

• 한국컴퓨터정보학회논문지
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• 제28권8호
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• pp.1-10
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• 2023

최근, 낸드 플래시 메모리는 비휘발성, 높은 집적도, 높은 내구성으로 인하여 다양한 컴퓨터 시스템에서 자기 디스크를 대체하고 있지만 연산 처리 속도 불균형 및 수명 제한과 같은 한계를 가진다. 따라서 낸드 플래시 메모리의 단점을 극복하고자 디스크 버퍼 관리정책들이 연구되고 있다. 비록 이러한 관리정책들이 다양한 작업 환경과 응용 프로그램의 실행 특성을 반영하는 것은 명확하나, 이들을 위한 기초 관리 정책 결정 방식에 대한 연구는 그에 비하면 미흡하다. 본 논문에서는 낸드 플래시 메모리를 효율적으로 활용하기 위한 기초 관리정책 제안 모델인 FRM을 소개한다. FRM은 워크로드를 다양한 특성에 따라 분석하고 낸드 플래시 메모리가 가지는 특성들과 조합하는 모델로, 이를 통해 작업 환경에 가장 알맞은 기초 관리 정책을 제시한다. 결과적으로 제안하는 모델은 학습 데이터와 검증 데이터에 대해 Accuracy와 Weighted Average 측면에서 각각 92.85%와 88.97%의 기초 관리정책 예측 정확도를 보여주었다.