• IE interfaces
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• v.15 no.4
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• pp.338-348
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• 2002

In this paper, we present a restricted tabu search(RTS) algorithm that schedules jobs on identical parallel machines in order to minimize the maximum lateness of jobs. Jobs have release times and due dates. Also, sequence-dependent setup times exist between jobs. The RTS algorithm consists of two main parts. The first part is the MATCS(Modified Apparent Tardiness Cost with Setups) rule that provides an efficient initial schedule for the RTS. The second part is a search heuristic that employs a restricted neighborhood generation scheme with the elimination of non-efficient job moves in finding the best neighborhood schedule. The search heuristic reduces the tabu search effort greatly while obtaining the final schedules of good quality. The experimental results show that the proposed algorithm gives better solutions quickly than the existing heuristic algorithms such as the RHP(Rolling Horizon Procedure) heuristic, the basic tabu search, and simulated annealing.

• Korean Journal of Computational Design and Engineering
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• v.18 no.3
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• pp.211-223
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• 2013

Today's ever-increasingly competitive shipbuilding market makes it essential for a shipbuilding company to have more efficient production processes and higher productivity as well as better design ability to obtain its competitiveness. A well-established production execution schedule plays an indispensable role to achieve this goal. Most shipbuilding companies carry out an evaluation on their mid-term plan once it is established. However, no evaluation activity exists for a production execution schedule, because practically all the companies depend on the field workers for the production execution scheduling. In this study, a prototype of a ship production execution schedule evaluation system is developed based on the component based design (CBD) methodology. This system enables one to make a production execution schedule that reflects up-to-date shipyard situation and to validate whether the schedule is feasible or not by running a production simulation according to the schedule. Users can also make use of the system as a decision supporting tool that compares several different execution schedules and evaluates which one is the best execution schedule.

• Journal of Internet Computing and Services
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• v.22 no.2
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• pp.41-50
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• 2021

According to the progress of IT and data processing technology, the usage of internet increased rapidly and various smart devices are appearing. As such, modern people use smartphone to acquire informations they wish and also on daily life including leisure activity free of place. This study has designed and implemented schedule managing application that can help effective managing of our daily life, such as taking note of schedule and sharing appointments. The schedule managing application in this study offers diary taking, sharing the registrated schedule with other users on kakaotalk, saving the deleted schedule or diary to certain folder when users delete file, continuous alarm of daily schedule function together with schedule registration function. The application which is differentiated to other applications and raised usage is expected to effectively manage the busy everyday life.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2008.10a
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• pp.299-303
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• 2008

In this paper, we discuss the schedule problems for Korean Professional Baseball League (KPBL) and propose approaches to solve these problems by applying Integer Programming. A schedule in a sport league must satisfy lots of constraints on timing such as organizational, attractiveness, and fairness requirements. Organizational requirements cover a set of rules which have to guarantee that all the games can be scheduled according to the regulations imposed by Korean Baseball Organization (KBO). Attractiveness requirements focus on what stadium visitors, television spectators, and the clubs expect, that is, a varied, eventful, and exciting season. Fairness requirements have to guarantee that no team is handicapped or favored in comparison with the others. In addition to finding a feasible schedule that meets all the constraints, the problem addressed in this paper has the additional complexity of having the objective of minimizing the travel costs and every team has the balancing number of the games in home. We formalize the KPBL problem into an optimization problem and adopt the concept of evolution strategy to solve it. Using the method proposed, it is efficient to find better results than approaches developed before.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.26 no.2
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• pp.68-74
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• 2003

Modem automated manufacturing processes employ automated guided vehicles(AGVs) for material handling, which serve several machining centers(MCs) in a factory. Optimal scheduling of AGVs can significantly help to increase the efficiency of the manufacturing process by minimizing the idle time of MCs waiting for the raw materials. In this paper, we will analyse the requirements for an optimal schedule and then provide a mathematical framework for an efficient schedule of material delivery by an AGV. With this model, the optimal number of MCs to be utilized will also be determined. Finally, the material delivery schedule employing multiple journeys to the MCs by the AGV will be carried out. Through rigorous analysis and simulation experiments, we shall show that such a delivery strategy will optimize the overall performance.

• Journal of Industrial Technology
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• v.27 no.A
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• pp.61-67
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• 2007

The construction machine is the composite machine assembled by about 30,000 parts. Excavator, one kind of a construction machine, plays the leading role for export of construction equipment. It is generally impossible to produce all of the items within one company. Especially the supply of hydraulic control valves, one of the core part of the construction equipment, depends on the import heavily. So it is important to make an efficient production plan of hydraulic control valves in the company. The most important thing for the production scheduling of a hydraulic control valve is to make production schedule keeping the start date for assembly line for an excavator and to make minimization of the stock level. The production plan of hydraulic control valve includes the decision of the quantity supplied by subcontractor. This paper presents a scheme for a scheduling system of the hydraulic control valve considering the schedule of the assembly line for excavator production. This paper provides a methodology, which can make a plan of supply and production and generate a detailed schedule for daily production.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.8 s.179
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• pp.2131-2142
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• 2000

As recent production facilities are usually operated with unmanned material-handling system, the development of an efficient schedule with deadlock avoidance becomes a critical problem. Related researches on deadlock avoidance usually focus on real-time control of manufacturing system using deadlock avoidance policy. But little off-line optimization of deadlock-free schedule has been reported. This paper presents an optimization method for deadlock-free scheduling for Job-Shop system with no buffer. The deadlock-free schedule is acquired by the procedure that generates candidate lists of waiting operations, and applies a deadlock avoidance policy. To verify the proposed approach, simulation resultsare presented for minimizing makespan in three problem types. According to the simulation results the effect of each deadlock avoidance policy is dependent on the type of problem. When the proposed LOEM (Last Operation Exclusion Method) is employed, computing time for optimization as well as makespan is reduced.

• Journal of the Korean Society of Safety
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• v.22 no.1 s.79
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• pp.7-12
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• 2007

There are two kinds of design process for sprinkler system. one is pipe schedule system and the other is hydraulically designed system. We have inefficient results when we design by hydraulically designed system because the design process for sprinkler system is restricted by domestic fire code. Therefore, it is essential to do an introduction of hydraulically designed system which is based on engineering for enhancing reliability and efficiency of sprinkler system. This study presents points at issue by comparing and studying design standards of sprinkler system from Korea, Japan and NFPA, and presents improvement plans of national fire safety code of sprinkler system by processing, comparing and analyzing designs according to piping schedule and hydraulically designed system about domestic objects. Installation standards of sprinkler system have to be applied not by object buildings but by hazard classification. It is hard to design an efficient sprinkler system for fire control when water supply requirement of sprinkler systems allocated according to a size of a building because the same purpose but other buildings may request more water requirement or less. We should sublate the pipe schedule system from national fire safety code and need to introduce the hydraulically designed system. The pipe schedule system presents easy access because it is based on the forecasted engineering calculations but it is applied to only small buildings like NFPA due to its low reliability.

• Journal of Digital Contents Society
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• v.17 no.4
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• pp.257-263
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• 2016

Cable drum schedule is the final step for the electrical equipment of the power plant, and is assigned cables to efficiently cable drum. In this paper, we have implemented an automated program which cables are scheduled in accordance with the capacity of the cable drum for each cable code. Proposed cable drum schedule was applied to the dynamic programming algorithm to effectively solve the optimization problem, and the implemented program is conducted so as to verify the proposed model. The experiment results show that implemented program eliminates the errors that can occur existing method, so we were able to reduce the design time of cable drum schedule. Cables for the electrical equipment of the power plant is designed to at least 2 million units or more. Thus the automation program to provide applies, it is considered that the design time of the cable drum schedule can be greatly reduced without serious error.

• Journal of Advanced Navigation Technology
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• v.2 no.2
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• pp.143-156
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• 1998

Incheon International Airport(IIA) is planned to open in about two years. Korean government has an ambition to make IIA a major hub airport in Northeast Asia. The most essential and required condition for an airport to be a successful hub airport in a certain region is to have more efficient flight service network than the other airports in the same region. IIA should compete with Japanese airports to be a major hub in Northeast Asia because Japanese government also has a plan to expand greatly the airport capacity in Tokyo area and Kansai airport in Osaka. It is necessary for both IIA and Korean national air carriers to compose efficient flight service network considering hub competition with Japanese major airports. As the liberalization of international air transport industry would give more marketing freedom to airlines, they would plan the flight service network and flight schedule based on market analysis instead of governmental regulations. In the economically liberalized environment, it is very required to analyze air passengers' flight choice behaviour in order to induce other carriers and passengers through IIA's attractive flight service network. Disaggregate model is more appropriate than aggregate model to analyze consumers' behaviour. The information derived from disaggregate choice model of air passengers could be utilized in devising efficient flight network and schedule plan. Value of travel time or trade off ratio between flight frequency and travel time which could be estimated from discrete choice model could be utilized for scheduling an efficient flight plan for airlines and composing efficient flight service network for IIA.