• Journal of the Korean Society for Railway
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• v.8 no.6 s.31
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• pp.507-512
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• 2005

Railroad transportation system has experienced major changes due to KTX introduction. Kyungbu corridor especially Seoul to Cheonan has line capacity problem and its solution has been a primary concern to researchers and policy decision makers. This study explored pattern of train operation between Seoul and Cheonan after the introduction of KTX in 2004. Both the number of trains and available seat capacity per day have increased but maximum number of trains per specific hour has not been changed much. Demand for train shows that if concentrated in a specific time, so number of trains during the peak hour should be increased. But, it is difficult ? 새 line capacity, so increasing seat capacity per train might be an option. An increase in an avaliable sear should be considered the characteristics of each train lines.

• Korean Management Science Review
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• v.12 no.1
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• pp.1-17
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• 1995

The success of cell manufacturing applications in FMS rests on the effective cell formation to maintain the independent relations both between machine cells and between part families. This paper presents an integrated method for concurrent formation of cells and families with no E.E (Exceptional Element) in FMS with alternative routings. To determine the maximum number of cell and family with no E.E, mathematical conditions and properties are derived. New concept of nonsimilarity is introduced for each machine and part based on machine-operation incidence matrix and part-operation incidence matrix. To concurrently form the cells and families, integer programming based mathematical models are developed. For the predetermined number of cell or family, model I is used to identify whether E.E exists or not. Model II forms cells and families considering only nonsimilarity. But model III can consider nonsimilarity and processing times. The proposed method is tested and proved by using numerical examples.

• Journal of the Korean Data and Information Science Society
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• v.18 no.1
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• pp.31-40
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• 2007

Many previous researchers tried to analysis relationship between financial index of hospitals such as revenue, expenses, and profit and hospital outcome such as number of inpatient and outpatient or, between that financial index and hospital size including number of hospital beds. However, these studies did not find exact relationship between financial index and hospital efficiency and productivity. Therefore, purpose of the study explores exact relationship between hospital financial outcome and hospital efficiency and productivity using adjusted inpatient days concept from American Hospital Association. Through the empirical analysis, the researchers find that hospital profit has the U-shape quadratic function to operation ratio. 66.9% of operation ratio is changing point and hospitals with 55.8% through 75.0% of operation ration have experience deficit situation. Considering the hospital circumstance, Korean hospitals would be to maintain general hospital type with various specialty departments.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.509-512
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• 2013

An inappropriate space zoning plan causes the unnecessary transportation of construction material and equipment among work areas and increases the disorder of work space. Space zoning is an essential operation management technique which contributes to reduce the process and/or operation idle-time. This paper introduces a method that computes the idle-times between construction operations (or processes) by using Web-CYCLONE. It allows computing with idle-times that affect the construction productivity. Using the idle time between operations and between processes, it computes the optimal number of zones and finds the optimal combination of zones that minimize the idle times. The method contributes to minimize the idle times relative to the operation schedule using complete enumeration. This paper presents the system prototype in detail. A case study is presented to demonstrate the system and verifies the validity of the model. It allows a project manager to establish space zoning plan that effectively segregates a project into optimal number of construction zones and to assign the constrained resources (e.g., laborer, equipment).

• Proceedings of the KSRS Conference
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• v.2
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• pp.824-826
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• 2006

The number of satellite under operation is being on the increase, however, because the number of operator is limited the reliable control system is necessary for stable mission operation. Especially it is necessary that error event indication such as colour or sound should be displayed with high reliability for intuitional monitoring. The limit range of KOBAS2 provides realistic value that is defined with in-orbit value and related document. It makes it possible for operator to monitor a number of telemetry data easily through single screen system instead of monitoring each mnemonics. The development and operation experience of KOBAS2 will contribute to the development of the evolved automatic telemetry monitoring system for future mission.

• Journal of the Korean Operations Research and Management Science Society
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• v.22 no.3
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• pp.99-111
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• 1997

We consider a production system with post-operation and early set-up. As soon as there are no more units(raw materials) to process and the machine becomes idle, it undergoes a post-operation. After the post operation, if the number of waiting units is greater than or equal to m, it begins a set-up. After the set-up, if the number of units is greater than or equal to N($\geq$m), it begins to process the units. We first analyze the system by employing the decomposition property of the vacation queue. We, then, propose an algorithm that finds the optimal threshold values ($m^*$, $N^*$). Finally we present some numerical examples and interprete the system behavior.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.46
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• pp.19-32
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• 1998

This paper addresses the processing route of parts and economic design in flexible manufacturing systems (FMSs) employing AGVs for Transport. Parts are processed through several workstations according to operation sequences. The machine of each workstation can do multiple operation functions. The operation stage of a part can be processed in several workstations, which are non-identical in functional performance. The objective of this paper is to determine the processing route of parts, number of machines at each workstation, number of vehicles. The model is assumed that the operation stage of parts can be processed at the only one among several available workstations. Parts are transported by automated guided vehicle system(AGVS). The decision criteria is to minimize the sum of processing cost, travel cost, operating cost. A model formulation is represented. A solution algorithm is suggested by using mathematical programming and simulation technique, and a numerical example is shown.

• Journal of the military operations research society of Korea
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• v.28 no.1
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• pp.29-46
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• 2002

This study focuses primarily on the construction of the wartime sealift operation model from US to Korea. There are some uncertainties in the process of sealift operation such as the procurement rate of materiel in US, the distribution of KFS on four initial position locations at the start of the activation, and the number of ports and berths in the SPOES and SPODS. The sealift capability, based on the allocation of sealift assets such as the number of vessels, berths, and ports, is evaluated through simulation. The simulation is executed with a baseline wartime scenario and then the results are analyzed through a sensitivity analysis. The military planner may use of this model as a standard for establishing effective and concrete sealift operation plan in the near future.

• Journal of Navigation and Port Research
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• v.43 no.3
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• pp.197-208
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• 2019

This paper assessed the impacts of the specification of the yard, handling equipment, and operation approaches on the expected number of re-handles during the loading operation for empty containers. When the various types of empty containers from multiple shipping liners are placed in separate spaces from each other, then the storage space cannot be fully utilized. So as to increase the utilization of the storage space, empty containers from multiple vessel liners are stored together incurring additional re-handles during the loading operation. Several formulas are derived for the estimation of the expected number of handles, including re-handles, for empty container retrieval from a bay. Transfer cranes and top handlers are utilized as handling equipment and various retrieval strategies are examined. Numerical analysis was conducted to assess the effects of various designs and operational parameters of the container stacking yard on the expected number of handles.

• The Journal of Information Technology
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• v.4 no.4
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• pp.51-63
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• 2001

Residue Number System has carry free operation and parallelism each modulus, So it is used for special purpose processor such as Digital Signal Processing and Neuron Processor. Magnitude comparison and sign detection are in need of Mixed Radix Conversion, and these operations are impediment to improve the operation speed. So in this Paper, MRC(Mixed Radix Converter) is designed using modified partitioned residue to speed up the operation of MRC, so it has progressed maximum twice operation time but increased the size of converter comparison to other converter.