• 한국경영과학회지
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• 제36권3호
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• pp.27-43
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• 2011

This paper investigates properties of the newsvendor problem under a schedule involving progressive multiple discounts compared with the standard newsvendor problem under a no-discounts schedule. Unlike most conventional approaches using the criticial fractile to analyze the retailer and/or supplier behavior(s) in the newsvendor problem, our approach uses riskless profit. From the properties revealed through a series of computational experiments, two conjectures regarding the relationship between the expected profits of both newsvendor problems as a generalization over Khouja's argument (1995) are raised. Those conjectures encourage newsvendors who may face budget or warehouse capacity restriction to use the extended model under a multiple-discounts schedule rather than the standard model with no-discounts schedule because they apply for every order quantity as well as the optimal order quantity. In addition to the conjectures, some insightful results are found to justify the implementation of a multiple-discounts schedule from the computational experiments and a new interpretation for implementation of a multiple-discounts schedule that has not been addressed in Khouja is provided.

• Journal of Astronomy and Space Sciences
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• 제27권4호
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• pp.407-412
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• 2010

Software reusability is one of key factors which impacts cost and schedule on a software development project. It is very crucial also in satellite simulator development since there are many commercial simulator models related to satellite and dynamics. If these models can be used in another simulator platform, great deal of confidence and cost/schedule reduction would be achieved. Simulation model portability (SMP) is maintained by European Space Agency and many models compatible with SMP/simulation model interface (SMI) are available. Korea Aerospace Research Institute (KARI) is developing hardware abstraction layer (HAL) supported satellite simulator to verify on-board software of satellite. From above reasons, KARI wants to port these SMI compatible models to the HAL supported satellite simulator. To port these SMI compatible models to the HAL supported satellite simulator, simulation scheduler is preliminary designed according to the SMI standard.

• 한국산학기술학회논문지
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• 제14권11호
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• pp.5890-5896
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• 2013

본 연구는 BIM 기반의 납품체계에서 IFC 파일의 공정정보를 축적하고 활용하기 위한 방안을 제시하였다. 이를 위해 첫 번째로, 공정정보의 활용방안에 대하여 기존연구를 분석하였고, IFC 표준을 고찰하였다. 두 번째로, 공정요소를 도출하기 위해 공정계획 수립절차를 분석하였으며, 공정프로세스와 상용소프트웨어를 분석하여 공정정보항목을 도출하였다. 또한 도출된 공정정보항목을 기반으로 IFC 스키마를 분석하여 IFC의 공정요소를 도출하였다. 마지막으로 IFC 납품파일의 축적을 위해 조달청의 시설사업 BIM 적용 기본 지침서를 분석하여 개념적인 BIM 모델의 납품프로세스를 통한 축적방법과 활용방안을 제시하였다. 본 연구는 국가적으로 진행되고 있는 BIM 도입과정에서 BIM모델의 정보를 축적하는데 기여할 것으로 기대된다.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.58-65
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• 2011

Construction Productivity is one of the most important elements in construction management. It is used in construction process scheduling and cost management, which are significant sector in construction management. It is important to make appropriate schedule and monitor how works are done within schedule. But construction project contains uncertainty and inexactitude, modifying construction schedule is being an issue to manage construction works well. Even though prediction and monitoring of productivity can be principal activity, it is hard to predict productivity with manager's experience and a standard of estimate. A large number of factors influencing productivity, such as drawing, construction method, weather, labor, material, equipment, etc. But current calculation of productivity depends on empirical probability, not consider difference of each influencing factor. In this research, the aim is to present a productivity predicting regression model of form work, which includes effectiveness of influences factors. 5 variables existed inside form work are selected by interview and site research based on literature review of existed various productivity influencing factors. The effectiveness and correlation of productivity influencing factors are analyzed by statistical approach, and it is used to make productivity regression model. The finding of this research will improves monitoring and controlling of project schedule in construction phase.

• 대한산업공학회지
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• 제37권2호
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• pp.132-143
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• 2011

This paper deals with a coal supply planning problem for power plants. We propose a mathematical optimization model to make decisions for coal pile sections, movement of reclaimers, and operation time of conveyor belts. The objective of the proposed model is to minimize the total operation time of conveyor belts and total movement time of reclaimers. The algorithm firstly selects a pile section by considering both the location of reclaimers and the stock amount on that pile section. And then the shortest path from the selected pile section has to be put into the operation schedule and check whether the total operation time is satisfied. Then finally the new schedule is updated. To this end, we have tested the proposed algorithm comparing with the general standard optimization package for the simplified problem SCSPP. From the numerous test runs for comparing with the existing coal supply scheduling methods, We see that the proposed model may improve the coal supply operation by reducing significant coal supply costs.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2009년도 추계 학술논문 발표대회
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• pp.193-198
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• 2009

It is an important issue in cost management to contract with the standard of cost estimate by the reasonable way in public construction projects. For the standard of cost estimate based on the Standard Estimating System, there is a difference of labor inputs between Standard Estimating System and actual quantities in construction projects. The duration of form work in multi-family housing depends on the manpower compared with other work, which is the critical path on the schedule management to be decided quality, and is the important to the cost management of construction projects. This study presented a simulation model of the productivity analysis for selecting the standard work type of form work in Multi-family housing construction projects.

• 한국인터넷방송통신학회논문지
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• 제12권6호
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• pp.155-164
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• 2012

개발인력을 투입하는 양에 상관없이 소프트웨어를 개발하는데 소요되는 일정 단축에는 한계가 있다. 그러나 획득되는 실제 개발된 소프트웨어 데이터들을 분석하여 보면 불가능한 단기간의 개발기간 또는 비현실적으로 장기간 개발기간 데이터들까지 포함하고 있다. 기존에 제안된 개발기간 추정 모델들은 이러한 제약사항을 고려하지 않고 실제 개발된 소프트웨어 모두를 대상으로 개발일정을 유도하고 있다. 본 논문은 개발 최소기간과 최적 개발기간(정상적인 개발기간)에 대한 기준을 제시한다. 제시된 기준은 실제 수행된 프로젝트를 대상으로 5개의 기준 중에서 가장 성능이 좋은 개발기간 추정 모델을 얻은 기준을 판단하였다. 또한, 이에 기반하여 개발기간을 추정하는 모델을 제시한다.

• 한국건설관리학회논문집
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• 제10권2호
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• pp.26-33
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• 2009

건설사업의 단계별 진행에 따라서 공정 스케줄의 정확도에 대한 요구수준이 달라진다. 본 연구의 목적은 건설사업의 초기단계에서 활용할 수 있는 표준공정모델을 제시하여 신속하게 전체 개략공기를 산정하는 체계를 제시하는 것이다. 표준공정모델을 적용하여 작업공정을 모듈화하고, Top-down 식 접근으로 상위레벨에서 공정모듈 간 작업연관관계를 분석함으로써 신속하게 프로젝트의 공사기간을 산정할 수 있다. 표준공정모델의 타당성을 검증하기 위해서 각 공정모듈의 작업기간이 일정하다고 가정하고, 가스 플랜트 공정에 대하여 적용시켰다. 그 결과 표준공정모델을 사용하여 계산한 개략 공사기간과 공정관리 툴을 사용한 상세 공사기간은 -3.1% 부터 +15.0%까지의 범위에서 차이를 가졌다. 이러한 결과는 제시된 표준공정모델이 일정 수준의 신뢰성을 가지는 공정 스케줄 정보를 제공하고, 사업기획과 타당성 분석 등 건설사업의 초기단계에서 신속하게 의사결정을 도울 수 있다는 것을 보여준다.

• 품질경영학회지
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• 제32권3호
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• pp.141-152
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• 2004

This study describes process and method to establish concurrent and/or sequential schedule planning for the system design process of the EIA632 standard. For this purpose, the study suggest Process and method that are context analysis of standard process, interface definition from activity decomposition, integration of related activities, and definition of concurrent and/or sequential work flow. The proposed process and method will contribute to minimize time loss that is emerged from activities iteration.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.643-645
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• 2003

In competitive electricity markets, each GenCo establishes generator maintenance schedule and submits to ISO those. Then, ISO reviews and arranges maintenance schedule of each GenCo to meet the standard for reliability. This paper presents the new optimization model which can apply to competitive electricity markets. The object of this model is to minimize schedules variation of each GenCo and to satisfy system reliability.