• IE interfaces
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• v.7 no.3
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• pp.171-180
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• 1994

Defined is a Multi-level Parallel Machine Flow-Shop (MPMFS) which reflects some real world manufacturing situations. Just-In-Time (JIT) philosophy is applied to the MPMFS scheduling in order to achieve lowering work-in-process inventory level as well as meeting due dates. A schedule generating simulator is developed. The latest start time of each operation is determined by a backward simulation followed by another forward simulation to analyze the schedule feasibility and actual inventory level. Reasonable schedules are available through adjusting some parameters for allowance factors such as set-up times of machines and other environmental changes. The SLAMSYSTEM under Window is employed for this processing with some input/output data handling processes devised under DOS.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5D
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• pp.587-595
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• 2008

Many studies on bus scheduling optimization have been done from the 1960s to recent years for establishing rational bus schedule plan that can improve convenience of bus passengers and minimize unnecessary runs. After 2000, as part of the Intelligent Transport Systems (ITS), the importance of the schedule management and providing schedule information through bus schedule optimization has become a big issue, and much research is being done to develop optimization models that will increase bus passenger convenience and, on the side of bus management, minimize unnecessary bus operation. The purpose of this study is to calculate the optimal bus frequency and create a timetable for each bus stop by applying DTR or DTRC model that use data for each bus stop and route segment. Model verification process was implemented using data collected from bus management system (BMS) and integrated transit-fare card system for bus route of Seoul's No. 472 line. In order to evaluate the reliability and uncertainty of optimal solution, sensitivity analysis was implemented for the various parameters and assumptions used in the bus scheduling model.

• Journal of the Korean Society for Railway
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• v.12 no.5
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• pp.623-630
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• 2009

The Korean railway system is a mass transit system consisting of a variety of train types such as common trains, high-speed train (KTX) and Metropolitan Express Railway (EMU). Its operation is based on the official timetable and it provides us with safe, accurate, quick and comfortable service. The objective of this study is to propose and prove more practical method for estimating line capacity by considering high-speeding and diversification of trains. In particular, the focus of this study is to reduce the discrepancy between the result of the theoretical line capacity estimation and the real line capacity of the operating agency of the Korean railway. In order to achieve the object, this study introduces a new railway capacity notion by considering TPS of line alignment, the operation type, train control and signaling system, etc. Through a practical schedule diagram exemplification, the result of the proposed method is verified as well.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.6
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• pp.602-611
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• 2004

Servo system has commonly adapted PI controller with fixed gains, because of its simplicity and determinative relationship among the parameters. The fixed gains PI system may be applied well to some operation conditions, but not non-linearities, complex and time variant operation conditions. For solving these problems, another conventional method, 'variable gun schedule according to speed', is published. The value of gain is determined according to the absolute value of the mover real speed. In this paper, FSTPIC(Fuzzy Self-Tuning PI Controller) is proposed based on various experiences to rapidly reduce speed error and to secure a good speed response characteristics. The effectiveness of proposed algorithms is demonstrated by comparing to two conventional gain systems via 4-quadrant operation.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.315-321
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• 2009

Since the KTX start its service on April 1st of 2004, KTX increased its share up to 17.4% (2008). It's the 2nd after the passenger car share of 59.2% in the national transportation, but the gap is still wide. In addition, because of the rise of goods' and oil price, the share of intercity express bus is growing up. Nevertheless Korail is trying to improve the train schedule and develop internodal transit system, the number of passengers of KTX is remain flat. KORAIL should start and proceed the tasks below. - Analysis of the 5 year's operation of KTX since the year of 2004 to make plans for the steady growth - development of the KTX operation plan for expansion of railway - preparing the operation of additional passenger rail services on the mail line for newly introduced trains. - expansion of KTX's service area after the introduction of KTX-II - introduction of other new trains - examination for the action plans to promote marketing in main-line including refinement of the rate structure

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.41-46
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• 2002

This paper deals with the exchange of tourists and the operation of sightseeing train encouraged by the inter- Korean cross-border railway project. First of all, how the inter-Korean cross-border railway project has developed will be discussed. After this, tile present tourism state, facilities, the state of railways and roads of North Korea, and major tourist attraction around the Kyonguisun will be shown. And then, several aspects on the agreements between the Korean National Railroad (KORAIL) and North Korean railroad system will be summarized. And, finally, the economic effect of the line including the operation schedule of the Kyonguisun sightseeing train, the demand forecast, the computation of railway fare, and profit sharing will be depicted.

• IE interfaces
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• v.14 no.1
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• pp.59-66
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• 2001

This paper introduces the case study that has been performed at the block paint shop, Hyundai Heavy Industries. First of all, the overall production processes of shipbuilding and research activities conducted by Korean are reviewed with a view-point of production planning. Then HYPOS(Hyundai heavy industries Painting shop Operation System) project is briefly described, which has several modules such as planning module, scheduling module, work order module, and DB(database) management module. Although the HYPOS system has several modules, this paper mainly focuses on the planning module that utilizes the rough-cut simulation algorithm to make a decision about the policy for production schedule. The HYPOS has been operated since June, 2000 and the operation data has been collected for the purpose of future evaluation about the performance of HYPOS system. The evaluation of HYPOS will be shown in a public domain as soon as the enough operation data is available.

• Journal of Korean Institute of Industrial Engineers
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• v.38 no.4
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• pp.262-275
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• 2012

This paper develops a multistage scheduling algorithm for the module operation of the LCD(Liquid Crystal Display) production systems and tests the efficiency of the proposed algorithm. The module operation is a multistage form composed of multiple sub operations of processes, and each stage is consists of multiple lines with the same kinds of machines. This paper presents a mathematical modeling reflecting the constraints of the LCD module operation and develops a multistage scheduling algorithm based on tabu search metaheuristic approach. For this purpose, an production order is assigned to a line of the sub operations and a sequence of the assigned order is rearranged to draw an efficient schedule. Simulation experiments test performance measures and show the efficiency of the proposed algorithm.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.92-95
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• 2004

A mixture experiment is a special type of response surface experiment in which the factors are the ingredients or components of a mixture, and the response is a function of the proportions of each ingredient. Evolutionary operation is useful to improve on-line full-scale manufacturing processes by systematically changing the levels of the process variables without jeopardizing the product. This paper presents an evolutionary operation procedure for large-scale mixture production processes based on simplex search procedure, which can be beneficial to practitioners who should improve on-line mixture process quality while meeting the production schedule of the mixture product.

• Industrial Engineering and Management Systems
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• v.9 no.1
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• pp.28-40
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• 2010

One of the most important objectives of the schedules in a container terminal is to minimize the ship operation time, which consists of discharging and loading operation times. Recently, dual cycling techniques have been used for improving terminal operations, especially for reducing the total empty trips of handling equipment. The main focus of this study is to reduce the empty trip times of yard trucks with minimum delays for ship operations. A heuristic algorithm, modified from a previous algorithm, is proposed to solve this problem. A simulation study is conducted to evaluate the effect of different types of discharging and loading schedules and different locating methods for discharging containers in terms of the performance of the system, including the percentage of the dual cycle operations of yard trucks.