• 한국시스템다이내믹스연구
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• 제8권1호
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• pp.211-227
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• 2007

Like the saying "You can't manage what you can't measure," performance measurement is considered as one of the most important management activities for the organizations in either private or public sector. Performance measurement, however, has thus far relied too much on financial statements. Realizing the importance of a more scientific and comprehensive performance measurement, many organizations have adopted several different systems in order to objectively estimate their balanced performance results. The Balanced Scorecard (BSC) has become a popular means to measure performance. But the BSC has also received some criticisms. In this paper four limitations in the use of the BSC are discussed : BSCs focus on unidirectional causality, are unable to distinguish delays between actions and their impacts on performance, integrate insufficiently strategy with operational measures, and lead to internal biases. We propose a system dynamics approach with causal loop diagram(CLD) to develop a Dynamic BSC in order to overcome these limitations. The results suggest that developing a BSC with system dynamics is a promising approach to supplement existing BSC frameworks.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
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• pp.686-691
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• 2005

We are concerned with the question of servicing warranties for repairable items. During the warranty period, each time an item fails the manufacturer has the obligation to restore the item to operational condition either by repairing the item or by replacing it by a new item. In this paper, we consider the repair-replacement strategies based on the condition of the failed item. For products with phase-type lifetime distributions where the phases represent the condition of the item, we develop algorithms to determine the expected cost of servicing a warranty and use it in making the repair-replacement decision. Illustrative numerical examples are presented. We also propose a dynamic strategy by taking the expected remaining warranty cost into consideration.

• 대한산업공학회지
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• 제31권4호
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• pp.341-348
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• 2005

This paper is concerned with the question of servicing warranties for repairable items. During the warranty period, each time an item fails the manufacturer has the obligation to restore the item to operational condition either by repairing the item or by replacing it with a new item. In this paper, we consider repair-replacement strategies based on the condition of the failed item. For products with phase-type lifetime distributions where the phases represent the condition of the item, we develop algorithms to determine the expected cost of servicing a warranty and use it in making the repair-replacement decision. Illustrative numerical examples are presented. We also propose a dynamic strategy by taking the expected remaining warranty cost into consideration.

• 무역상무연구
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• 제48권
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• pp.27-56
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• 2010

Pollution emissions from international shipping and port activities have a significant impact on public health and global climate changes. The purpose of this paper is to review the status of pollution mitigation measures implemented to date in port industry and find out some implications for Korean ports. For this aim, the clean air strategies of the world major ports including six USA ports (Los Angeles/Long Beach, Now York/New Jersey, and Seattle and Tacoma), two European ports (Rotterdam and Gothenburg) and Busan Port were considered. Various measures to reduce emission from ports are evaluated by sectors-ocean going vessels, cargo handling equipments, truck and rail-, on the basis of categories such as reduction control technologies, operational changes and market-based measures. The policy implications of this paper are as follows. First, Clean Air Act Plans of Korean ports are required as soon as possible. Second, integrated approach is required to reduce emission effectively. Finally, the effect of port-related emission reduction can be maximized when various measures are conducted on a regional basis including neighboring ports. Furthermore, regional or global-based approach is useful to guarantee the level playing field among ports.

• 경영과학
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• 제10권2호
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• pp.121-143
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• 1993

Traditional Manufacturing method is push system by plan made in advance and Japanese manufacturing method represented by JUST-IN-TIME is pull system which respond's to the demand flexibly. Both have their pros and cons. In general, it is well understood that push system is faster than pull system in the sense of manufacturing speed. However, pull system such as JIT excelles dramatically in the sense of work in process. Therefore, this paper is trying to put together to get alternative which has the advantage of both system. The objective of the paper is to enhance the effect of built-in manufacturing system without paying extra cost by way of introducing the alternative of the pull-push manufacturing strategic operational method.

• 한국항공운항학회지
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• 제23권2호
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• pp.57-62
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• 2015

As the issuance of type certificate and production certificate for KC-100 Naraon, Korea is ranked as the State of Design and the State of Manufacture for civil aircraft specified in the Convention on International Civil Aviation. It means that another responsibilities are imposed and new frameworks are required for the airworthiness management including the continuing airworthiness. So far the minimum airworthiness management system was sufficient as the State of Registry for the aircraft operations and safety management. However, we need to establish and maintain the airworthiness management system for the effective certification and oversight of our air operators and approval holders. This paper introduces the new obligations under the Convention on International Civil Aviation, reviews the current aviation regulations and procedures and presents the strategy for the establishment of the regulatory system to ensure the airworthiness of aircraft.

• 한국유통학회지:유통연구
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• 제1권2호
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• pp.141-172
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• 1996

This study is to investigate global logistics strategies of Korean electronics companies. in terms of service parts. According to the survey, Korean electronics companies were pursuing multi-level global logistics network such as global, continental, national, regional and service center echelon for improving the efficiency of service parts global logistics. Especially there was a tendency of developing new continental distribution centers. And the companies were exploiting efficiency through inventory control by multi-level echelon, demand forecasting by the product life cycle and supply and service lead time management. But there were some insufficient factors for the efficiency of global logistics operation at the construction of worldwide real time logistics information system and pursuit of the efficiency on the whole network including subcontractors. For the future competitive advantage of the Korean electronics companies, the following are suggested: 1) the establishment of arranged logistics channel adjusting each company's global strategy, 2) the construction of worldwide real time logistics information system, 3) the reengineering of all logistics procedures such as order processing, shipping, inventory control, etc., 4) the enhancement of the ratio of the supply from the external companies and the internal manufacturing subsidiaries at each continent, 5) and the pursuit of operational internalization of external subcontractors.

• 조명전기설비학회논문지
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• 제22권7호
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• pp.22-27
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• 2008

A new excitation strategy for a Switched Reluctance Motor with Auxiliary Winding(SRMAW) is described and tested. The proposed scheme has auxiliary winding with one diode which is wound over all poles in one winding. In this scheme, auxiliary winding is used to reduce magnetic stress during commutations. The abrupt change of a phase excitation produces mechanical stresses resulting in vibration and noise. The acoustic noise is reduced remarkably through the 2-stage commutation. The operational principle and a characteristic comparison of the conventional SRM show that this scheme has some advantages including noise reduction as well as high drive efficiency.

• 한국정보처리학회논문지
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• 제4권6호
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• pp.1557-1564
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• 1997

본 논문에서는 프롤로그 프로그램의 수행을 제어하기 위한 하나의 기능으로서 수항목(count term)이라는 새로운 기능을 제안한다. 그 목적은 사용자와 프로그래머에게 답 또는 증명의 수를 제한하는 기능과 프롤로그 프로그램의 수행을 제어하는 데 편리함을 주기 위한 것이다. 따라서 그를 위한 구문과 작동적 의미를 제시하였으며 WAM(Warren Abstract Machine)에서 백트랙킹시 관련된 명령어를 수정하여 수항목의 구현 방법을 제시한다.

• 대한전기학회논문지
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• 제43권6호
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• pp.936-945
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• 1994

This paper proposes a new power converter which consists of two identical 3-phase PWM modulators and a novel resonant circuit. A new control strategy is integrated to realize the bidirectional power converter without an electrolytic link capacitor. The power flow between converters is bidirectional and the regenerative braking is inherent. The source side currents maintain sinusoidal waveforms with a unity power factor. It is observed in the experiment that by balancing the active power between the source and load side, the voltage across a small ceramic link capacitor can be maintained within a small deviation from the reference. Simulation results and experimental results are presented to verify the operational principles.