• Journal of the Korean Operations Research and Management Science Society
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• v.20 no.1
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• pp.115-130
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• 1995

This paper considers a single machine nonpreemptive scheduling problem with a given common due date. In the problem, the optimal job sequence is sought to minimize the sum of earliness/tardiness and flow time measures in the situation where all jobs are available at time zero, and weights per unit length of earliness/tardiness and flow time are V and W, respectively. Some dominant solution properties are characterized to deriva both an optimal starting time for an arbitrary sequence and sequence improvement rules. The optimal schedule is found to the case W .geq. V/. By the way, it is difficult to find the optimal schedule for the case W < V. Therefore, the derived properties are put on together to construct a heuristic solution algorithm for the case W < V, and its effectiveness is rated at the mean relative error of about 3% on randomly generated numerical problems.

• Korean Management Science Review
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• v.29 no.2
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• pp.143-155
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• 2012

The purpose of this study is to formulate and solve the scheduling problem to heat-treatment process in forging process and apply it to industries. Heat-treatment is a common process in manufacturing heavy forged products in ship engines and wind power generators. Total complete time of the schedule depends on how to group parts and assign them into heat furnace. Efficient operation of heat-treatment process increases the productivity of whole production system while scheduling the parts into heat-treatment furnace is a combinatorial problem which is known as an NP-hard problem. So the scheduling, on manufacturing site, relies on engineers' experience. To improve heat-treatment process schedule, this study formulated it into an MIP mathematical model which minimizes total complete time. Three methods were applied to example problems and the results were compared to each other. In case of small problems, optimal solutions were easily found. In case of big problems, feasible solutions were found and that feasible solutions were very close to lower bound of the solutions. ILOG OPL Studio 5.5 was used in this study.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.362-365
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• 2004

This study suggests an attribute code system for earned value management system (EVMS). The attribute code system can be used for integrating various EYM data from construction schedule and cost. If the suggested attribute code is used in EVM, sorting and typical classifying of EVM data is possible in the computerized system. Those functions are an effective management tool for construction manager comparing with other EVM tools.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.174-176
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• 2002

A total of 134 patients with stage 1 of non-small cell lung cancer treated by carbon ion beam of HIMAC NIRS were investigated for control rate and delivered dose. The delivered dose of every patient was converted to biological effective dose (BED) of LQ model using fraction number, dose per fraction and alpha beta ratio which shows the maximum correlation between BED and tumor control. The BED of every patient was classified to establish a BED response curve for control. Assuming fraction numbers, dose response curves were introduced from BED response curve. The total doses to realize several control rates were obtained for the treatment of small fraction number.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.429-432
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• 1999

In this paper, we propose a method to improve Genetic Algorithm using Boltzmann selection which Michael has suggested. But Michael uses temperature schedule(the initial temperature, the cooling rate), which can be applicable only to the limited range of problems. We propose a new method to find the critical temperature and the cooling rate as parameters of the temperature schedule. The critical temperature can be derived from the distribution of each individual＇s fitness. Through the application of the island model where each island has differing cooling rate, it is proved that it is unnecessary to find the optimal cooling rate. The simulation on the TSP＇s with various city sizes proves the proposed critical temperature correct.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1466-1474
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• 2007

In large station with high density traffic, trains is hardly controlled by CTC but by station dispatcher because CTC has difficulties in monitoring all states of affairs happening within the station such as departs and arrivals of many trains from different lines and shunting trains between yards and platforms, etc. Therefore station dispatcher has to make quick decision about how to schedule all trains including trains to arrive and depart before long. And such decisions become harder when an unexpected delay occurs. This study suggests a mathematical model and algorithm about how to detect in advance and resolve efficiently the conflicts occurring within a station and it will be shown how to reduce delay using our approach by means of analysing the schedule of ChyungRyangRi station.

• Journal of Korean Institute of Industrial Engineers
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• v.37 no.4
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• pp.382-389
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• 2011

Salesperson Monitoring System (SMS) is geographic based information system that supports business auditing, sales area coordinating and customer management for each salesperson. Conventional SMSs focus mainly on the monitoring or logging functions, i.e., a salesperson locating or moving trail tracking. However, the schedules have been planned by human planner, and they have rarely been managed with a software system like SMS. In this paper, a mixed integer programming model for a salesperson routing schedule is provided. Then, 2-phase Genetic Algorithm (GA) is proposed to make salesperson routing schedule. Experimental results show a validity of the proposed method.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.883-886
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• 2002

A new exposure time scheduling scheme to implement the optimized photopolymer-based VHOE is proposed and using this method, the 8-view VHOE system is experimentally developed. The CGS dependence on the exposure energy is mathematically modeled using the fourth-order polynomial function and using this model optimized exposure-time schedule for recording the given multiple gratings in the photopolymer is calculated. In addition, basing on this suggested exposure-time schedule, 8-view VHOE is finally implemented and its performance is discussed.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.1159-1162
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• 2012

프로젝트 관리 성숙도(Project Management Maturity Model)란 프로젝트 관리 관련 업무 성숙도를 측정하는 것으로, 프로젝트 성공을 위해 관련 있는 업무가 어느 정도 수준으로 진행되고 있는가를 평가하는 목적으로 주로 사용된다. 본 논문에서는 프로젝트 관리 성숙도를 활용하여 프로젝트 관리 성숙도가 범위, 일정, 그리고 원가에 미치는 영향을 연구 하였다. 연구 결과로 프로젝트 관리 성숙도가 낮으면 범위 변경률이 커지고, 일정이 지연되며, 비용 또한 초과되는 것으로 나타났다. 본 연구의 성과를 토대로 기업이 프로젝트 관리 성숙도 향상을 위해 투자와 노력을 해야 한다는 것을 알 수 있다.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.941-946
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• 2005

It is essential for project managers to make schedule adjustment based on their professional experience, in terms of rescheduling action discussed in this paper. This paper discusses the topics of resource-constrained construction rescheduling by modifying the concepts of manufacturing rescheduling. Moreover, the influence factors of construction rescheduling problems are investigated and identified in this paper. According to initial schedule plan and present progress, a new rescheduling mechanism based on Constraint Programming (CP) techniques is developed to reschedule projects with the objective of minimizing total project cost or duration, under three rescheduling policies. Through case study, the behavior of three different rescheduling policies is analyzed and discussed in this paper.