• Journal of the Korean Operations Research and Management Science Society
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• v.36 no.3
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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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• v.27 no.4
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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.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5890-5896
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• 2013

This Study aimed at suggesting the plan for accumulating and utilizing schedule information of IFC file in BIM-based delivery system. For this Propose, First, literature review is conducted for analyzing utilization plan of schedule information and the IFC standard. Second, Schedule Planning process is analyzed to draw Schedule elements, and schedule information items is derived by analyzing schedule process and commercial software. Also, schedule elements in the IFC schema is derived by analyzing IFC schema through drawn schedule information. Finally, this study suggests a concept model accumulating and utilizing Schedule information included in IFC schema, and a conceptual delivery process of BIM model by analyzing BIM Application Guideline for Facility Project by PPS (Public Procurement Service) for accumulating IFC delivery files This study will expects to contribute to accumulate information of BIM model at the point of nationally introducing BIM.

• International conference on construction engineering and project management
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• 2011.02a
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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.

• Journal of Korean Institute of Industrial Engineers
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• v.37 no.2
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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.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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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.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.6
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• pp.155-164
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• 2012

The compression of software development schedule has a limit without regarding to a development manpower. However, the actually developed softwares includes the impossible short time or unreal long time date. Previously suggested models are driving the development schedule from all of the actually developed software without considering these constraints. This paper recommends a standard of minimum and the most suitable development time period. This paper has chosen a criterion that shows the best development schedule among 5 criteria based on the actually performed projects. Moreover, this paper suggests a model that estimates the development schedule based on the best criterion.

• Korean Journal of Construction Engineering and Management
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• v.10 no.2
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• pp.26-33
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• 2009

The required level of detail in scheduling depends on the stages in the construction life-cycle. The objective of this study is to provide a Standardized Schedule Model (SSM) with an aim to facilitate the estimating of construction duration in the planning stage. The SSM modularizes work items; establishes relations between preceding and succeeding activities; and calculates approximate construction duration. The estimated duration of the SSM was compared with the detailed duration from the commercial scheduling tool using actual work activities. The difference showed to be ranged between -3.1% and +15%, which demonstrates that the SSM can be feasibly applied to the approximate estimation of construction duration.

• Journal of Korean Society for Quality Management
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• v.32 no.3
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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.

• Proceedings of the KIEE Conference
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• 2003.07a
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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.