• Journal of Korean Institute of Industrial Engineers
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• v.22 no.2
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• pp.209-229
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• 1996

Scheduling problems which determine the sequence of jobs are one of the Important issues to many industries. This paper deals with a single-machine job sequencing problem which has complex constraints and an objective function. To solve the problem, an expressive constraint description language and an automatic code generator are developed for our scheduling system. The user just needs to describe the scheduling problem using the constraint description language that allows to express both quantitative and qualitative constraints as well as an objective function in real world semantics. Then, a complete scheduling program based on constraint satisfaction technique is automatically generated through the code generator. Advantage of this approach is that models of the scheduling problems are easily developed and maintained because models ore formulated by using the language which reflects real world semantics.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.11a
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• pp.67-70
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• 2006

Efficient scheduling for software development is a major concern for software engineers. A industry simultaneously performs a variety of projects with the limited resources without overdue. A way to overcome the limitation of resources is sharing of the resources through the projects. This study discusses the matrix organization for software development. A scheduling for matrix organization is a special case of project management problem. The ultimate goal of scheduling problem in this study is to reduce the overall duration of the multiple projects. A genetic algorithm is presented to solve the scheduling problem of the matrix organization and is substantiated with numerical results.

• Korean Management Science Review
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• v.29 no.3
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• pp.183-192
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• 2012

For the past several decades, personnel scheduling and rostering problem has been one of the most popular research topics in optimization area. Among the numerous applications, airline (aviation) industry has been given most attention due to the economic scale and impact. Most of the literatures about the staff scheduling problem in airline industry are dealing with the air crew, pilots and flight attendances, and the rest of the literatures are about the ground staff, by whom cleaning, maintenance, fueling of aircraft and handling luggage are done from landing to taking off. None of the literatures found by the authors are dealing with the airline ground crew. In this paper roster of airline ground crew, who is responsible for issuing boarding pass, checking baggage, etc, is introduced, formulated and solved using CPLEX. Some expressions of the mathematical formulations, which are not suitable input format of the CPLEX, were transformed. Numerical examples are presented for the validation of proposed scheduling system.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.3
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• pp.43-50
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• 2014

In this paper, we deal with a single machine scheduling problems integrating with step deterioration effect and a rate-modifying activity (RMA). The scheduling problem assumes that the machine may have a single RMA and each job has the processing time of a job with deterioration is a step function of the gap between recent RMA and starting time of the job and a deteriorating date that is individual to all jobs. Based on the two scheduling phenomena, we simultaneously determine the schedule of step deteriorating jobs and the position of the RMA to minimize the makespan. To solve the problem, we propose a hybrid typed genetic algorithm compared with conventional GAs.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.1111-1116
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• 1993

In this study, we discuss the design of the expert system for the scheduling of the FMC(Flexible Manufacturing Cell) consisting of the several versatile machines. Due to the NP property, the scheduling problem of several machine FMC is very complex task. Thus we proposed the two heuritstic shceduling algorithms for solving the problem and constituted the algorithm based of solving the problem and constituted the algorithm base of ISS(Intelligent Scheduling System) using them. By the rules in the rule base, the best alternative among various algorithms in algorithm base is selected and applied in controlling the FMC. To show the efficiency of ISS, the scheduling output of ISS and the existent dynamic dispatching rule were tested and compared. The results indicate that the ISS is superior to the existent dynamic dispatching rules in various performance indexes.

• Journal of the Korean Society for Railway
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• v.9 no.1 s.32
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• pp.50-56
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• 2006

This paper presents a mathematical model of the long-term track tamping scheduling problem in the Korean highspeed railway system. The presented model encompasses various operational field constraints, moreover improves a state-of-the-art model in extending the feasible space. We show the model is sized up to intractable scale, then propose another approximation model that is possible to handle with the present computer system and commercial optimization package, directly. The aggregated index, lot, is selected, considering the resolution of the planning horizon as well as scheduling purpose. Lastly, this paper presents two test results for the approximation model. The results expose the approximation model to quite promising in deploying it into an operational software program for the long-term track tamping scheduling problem.

• Journal of Korean Institute of Industrial Engineers
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• v.29 no.4
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• pp.304-311
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• 2003

This paper considers a new variation of scheduling problems where jobs are dispatched in batches. The variation is the case where the batch sequence is fixed. The objective is to minimize the sum of the completion times of the batches. This simple environment has a variety of real world applications such as part kitting and customer order scheduling. We show that this problem is binary NP-complete when there exist two machines. For the same problem, we develop an optimal dynamic programming (DP) algorithm which runs in pseudo-polynomial time. We finally prove the optimality of the DP algorithm.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.826-828
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• 1996

Genetic Algorithm(GA) is a searching or optimizing algorithm based on natural evolution principle. GA has demonstrated considerable success in providing good solutions to many nonlinear, multi-dimensional optimization problems. The preventative maintenance scheduling is a kind of dynamic optimization problem with constraints. This paper applies GA to the preventative maintenance scheduling problem. In the case study, we can get the preventative maintenance scheduling of 3-generators during 8 weeks using GA. It is shown that GA can be available to the preventative maintenance scheduling problem.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.44
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• pp.197-205
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• 1997

Manufacturers can meet the due dates of orders by using overtime, in which case, additional cost incurs for the amount of overtime. Although many studies have been reported on scheduling, only a few papers are founds on production scheduling using overtime. We consider the problem of production scheduling using overtime on a single machine, in which each job has a given due-date, a constant processing time. We assume that the daily overtime does not exceed the daily regular operation time. The objectives is to minimize the total overtimes, while meeting all due dates. We first present a mathematical model, and then suggest a heuristic algorithm for the problem.

• IE interfaces
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• v.16 no.2
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• pp.201-210
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• 2003

The purpose of this research is to develop a scheduling system for CAL (Continuous Annealing Line) in Cold Rolling Mill. Based on CSP (Constraint Satisfaction Problem) technique in artificial intelligence, appropriate algorithms to provide schedules satisfying all the constraints imposed on CAL are designed and developed. Performance tests show that the proposed scheduling system outperforms human operators in case of aggregating the same attributes and minimizing the thickness differences between two adjacent coils.