• Journal of the Korea Society for Simulation
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• v.8 no.2
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• pp.73-85
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• 1999

In this paper, the productivity estimation of the painting line in an automobile plant is studied. To improve the bottleneck and the weak point of the process, computer simulations are performed. In determining the system specification, the status of the conveyor lines and the other physical facilities are considered in order not to intervene with each other and to satisfy the painting facility restrictions. As simulation parameters, production performance ratio, number of hanger and dolley, down time, speed of conveyor and the pitch of a painting body are chosen on the basis of exhaustive field evaluation to study their effects on the capacity of the process. The results of the simulation show that we can improve the capability of they system without additional investment to the plant facility. The best condition for the maximum capacity of the process is selected by comparing the alternative computer simulation results. As a simulation language, Promodel is used which is very useful and easy to use in manufacturing oriented simulation.

• Journal of Environmental Science International
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• v.10 no.4
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• pp.253-258
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• 2001

A macroeconomic minimodel was simulatedto suggest the public for sustainable us of Nakdong River Basin. The minimodel for the simulation shows the interrelationships between natural environment and economic activity. Topsoil, water, economic assets, and money stock are plotted for 300 years, beginning with 1996 in each simulation. The computer simulation runs suggest that the Nakdong River Basin system in the near future may strongly be influenced by the favorable availability of outside resources, while the economic assets and money stock may be declined by indigenous environmental stock depletion. The simulation run made under the constant decrease in systems purchased inputs with investment ratio of developed country and for sustainable use. The results of simulation shows the recover of natural environment and decrease of economic activity under these condition. Therefore, the economic structure of Nakdong River Basin should be transformed from the present industrial structure to the social-economic structure based on an ecological-recycling concept which depend on renewable resources rather than industrial structural which depend on outside resources.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.509-516
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• 2011

As a high interest in low-carbon transportation, investment of the railway systems has increased. Because the layout of tracks is very complex and the movement pattern of the train is not fixed in the railway depot, there is a need for simulation technology for a more accurate analysis of the railway depot. But most previous researches and commercial simulation tools focused on the main-line. This research suggests the simulation framework for analysis of the railway depot. The simulation framework will help to develop the simulation tools of the railway depot.

• Journal of the Korea Society for Simulation
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• v.11 no.3
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• pp.59-65
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• 2002

Semiconductor wafer fabrication is a business of high capital investment and fast changing nature. To be competitive, the production in a fab needs to be effectively planned and scheduled starting from the ramping up phase, so that the business goals such as on-time delivery, high output volume and effective use of capital intensive equipment can be achieved. Project executed that use conveyor in bay semiconductor A line. But conveyor capability is lacking and rundown happened in equipment. Do design without normal simulation and conveyor system failed. The comparison is peformed through simulation using .AutoMod a window 98 based discrete system simulation software, as a tool for comparing performance of proposed layouts. In this research estimate optimum conveyor capability, there is the purpose.

• Journal of the Korea Society for Simulation
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• v.8 no.2
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• pp.87-100
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• 1999

A manufacturing environment without a computerized system causes numerous problems, since many important decisions are made based on the experience of veteran staffs. Especially, when a strategy for the improvement of manufacturing efficiency is considered, it is hard to predict the effect of the strategy. A solution to the problem without large investment of the computerized system is the simulation study. This paper shows the modeling and simulation based on DEVS(Discrete Event System Specification). Two types of models are implemented, one for representing the current production strategy and the other for the new strategy. The new strategy is expressed as priority rules within the model. The process in concern is the metal grating production process in which the size of the group, for applying a specific cutting and scheduling strategies, is one of the important factors in improving the production efficiency. Some reliable criteria for the evaluation related to the production effeciency are established from the simulation study.

• Journal of the military operations research society of Korea
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• v.9 no.2
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• pp.23-30
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• 1983

A simulation study was conducted to determine optimum capacity of Navy drydock facility using GASP-IV, an advanced FORTRAN-based simulation language, under demands of regular overhauls and emergency repairs by ships of an hypothetical fleet composition. Three year dock usage data was analyzed to produce probability distributions underlying drydock repair demands. The present facility size of two drydocks was simulated and was found to be somewhat short of adequate service capability, showing excessive average waiting time and average queue length. The simulation model was then modified to include an additional drydock of similar size as the other two and a year's simulation was again conducted. All repair needs were quite satisfactorily met and all docks showed very high utilization factor (0.98). This contributed to an increase in the fleet's ship availability from 0.95 to 0.99. This study illustrates the usefulness of simulation technique as a tool for analyzing policy alternatives in military long-term investment areas.

• Proceedings of the Korea Society for Simulation Conference
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• 1998.10a
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• pp.17-20
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• 1998

The purpose of this paper is to develop a port simulation program for Inchon Port. The arrival and departure data from Inchon Port are analyzed, several probability density functions for the interval time and service time are estimated, and the berthing rules are constructed based on experts experiences. The port simulation program is written in visual basic considering the interarrival p.d.f., service rate p.d.f., berthing rules, and dual-dock system, and is used to analyze the effects of the changes in ship arrival rate and service rate upon the demurrage. It is expected that we can use the simulation results in order to prepare proper service level and to evaluate the appropriate investment strategy to be planned.

• Journal of Korea Port Economic Association
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• v.38 no.2
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• pp.95-107
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• 2022

Shipping companies earn profits through cargo transportation, and therefore, investment decisions to purchase ships are more important than anything else. Nevertheless, the cash flow discount method was mainly used in the economic analysis method, which assumes that all situations are static. This study shows that the real option model is useful in the economic analysis of ship investment. This economic analysis took into account the irreversibility of investment and uncertainty of benefits. In particular, this study used a binary option price determination model among real options. In addition, the simulation was conducted using actual investment data of A shipping company. As a result of the analysis, the investment value of used ships according to the net present value method was analyzed as negative (-), but the investment value in the real option model reflecting the flexibility of decision-making was evaluated as having positive (+) economic feasibility. It was analyzed that economic feasibility is affected by profit volatility and discount rate. Therefore, this study is expected to help shipping companies make more flexible decisions by using the real option model along with the existing net present value method when making ship investment decisions.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.11
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• pp.13-22
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• 2018

At the time when zero energy building is expected to be generalized, this study examines whether the investment in the passive element or the active element is more effective in terms of energy in the construction process of zero energy building. In other words, the effect of energy demand by passive element and the change of energy generation by active element are examined in terms of the same investment cost. The purpose of this study is to examine the change of energy demand by passive element and the change of energy generation by active element in zero energy building and to make reasonable investment decision by comparing energy with cost aspect. For this purpose, we selected the buildings to be subjected to energy simulation and derive the required energy amount and energy generation amount by using meteorological data of four regions in Korea. The change of energy demand and energy generation according to the change of application condition was derived. In order to compare and analyze the changes in energy demand and generation at the same cost standard through price survey and quotation of window and photovoltaic power generation equipment.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.411-416
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• 1991

Operation simulation is a key factor to evaluate investment and operation in a power utility. Probabilistic production simulation is of major concern. With pumped-storage plant, production simulation is not an easy task, because its economy should fully be exploited. In addition, usual operation interval is a week rather than a day. Most existing models are based on approximate production simulation such as adopting simple priority orders of generations. This study is based on the more elaborate model developed by authors. Further, a policy of weekly coordination is established based on the Maximum Principle. Chronological load curve instead of usual load duration curve is used and the accuracy in simulation is enhahced. Resulting economics are compared. Deviation between these two toad curve is shown.