• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.845-850
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• 2002

In this study we consider a flow-line CONWIP System with Compound Poisson Demands. The processing times of each workstation follow a Coxian-2 distribution. The demands that are not satisfied instantaneously are either backordered or lost according to the number of backordered demands that exist at their arrival instants. For this system we develop an approxi­mation method to obtain the performance measures such as steady state probabilities of the number of parts at each station, the average number of backordered demands and the proportion of the lost demands. Comparisons with simulation have shown that the approximate method provides fairly good results.

• Journal of Korean Institute of Industrial Engineers
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• v.31 no.3
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• pp.210-218
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• 2005

In the current global business environment, it is very important how to allocate products from the producer to buyers (or distributors). Sometimes some buyers can order more than pertinent demand due to inappropriate forecasting customers' orders. This is the big obstacle to the efficient allocation of products. If the producer can become aware of buyers' pertinent demand, it is possible to realize the high-level order fulfillment through the effective allocation of products. In this study, a new allocation policy is proposed considering buyers' demands. The backpropagation algorithm, one of algorithms in neural network theory, is used to find pertinent demands from the distributors' orders. In the experiment, an allocation policy considering buyers' demands outperforms previous allocation policies.

• IE interfaces
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• v.17 no.spc
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• pp.79-89
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• 2004

Supply Chain (SC) can balance demands with supply activities as executing Supply Chain Planning (SCP). The fluctuated demands, however, will break the balance between demand and supply. It means that the present SCP is useless in responding the changed demands. Thus it is necessary for SCP to be updated with changed demands. We call this procedure as Supply Chain Replanning. However, the existing measures for SC can not deal with the balance between supply and demand so that they can not detect effectively the timing of replanning. For this reason, a new performance measure, Balancing Point, is developed using momentum, a concept of Physics. It can treat the balance between supply and demand. Also, a replanning method based on Balancing Point is proposed. The proposed method is more effective than the existing replanning method, periodic replanning method and net inventory method.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.36
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• pp.113-120
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• 1995

Much of the past work regarding repairable item stockage has concentrated on the development of models and policies for systems in steady state. However, there are important situations in which the transient behavior is most important. A dramatic example of this is the potential dynamic behavior exhibited by demands and service in the deployment of an Air Force squadron at the onset of a conflict. The purpose of this paper is to derive some probability distributions necessary for providing an integrated approach for a multi-echelon inventory system with nonstationary demands and service rates.

• International Journal of Railway
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• v.5 no.4
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• pp.139-143
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• 2012

In Korea, almost 700 industrial parks are under operation. Generally, industrial parks consist of national industrial parks and local industrial parks which are managed by a central government and by local governments respectively. The developing countries such as Korea, China and Vietnam etc. have constructed many industrial parks, which result in the change of land use pattern and also affect future trip demands. Therefore, in estimating traffic demands, it is very important to consider the industrial park development. This study aims to improve the methodology in estimating a freight trip generation rate with the data based on a nationwide commodity freight survey. The result showed that it is desirable to apply freight trip generation rate by the industry sector in estimating freight trip generations and using the production area of firm as an indicator. Specially, the reliability of the rates through a survey could be made sure because a sample rate based on firms in industrial parks was over 25% and the response rate was over 67%. The sample rate and response rate are very superior as compared to surveys conducted in many other countries. Because industrial parks have significant effects on forecasting transportation demand in pre-feasibility studies of transport and logistics projects, it is expected that the accuracy of freight trip demands would be improved through the results of this study.

• Journal of Korean Institute of Industrial Engineers
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• v.40 no.3
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• pp.313-320
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• 2014

We consider the problem to find economic inventory quantity of a single commodity under stochastic demands and order cancellation. In contrast to the traditional economic production quantity (EPQ) model, we assume that once the amount of inventory reaches to a predetermined level of quantity then the production is not halted but its production speed decreases until the inventory level drops to zero. We establish two probabilistic models representing the behaviors of both the high-production period and low-production period, respectively, and derive the relationship between the level of inventory and costs of production, cancellation, and holding, from which the quantity of economic inventory is obtained.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.7
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• pp.1-10
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• 2003

In order to analyze the water supply capacity in an estuary reservoir, a system composed of daily water balance model and daily inflow model was developed. The agricultural water demands to paddy fields, domestic water demands to residential areas, and industrial water demands to industrial complexes were considered in this daily water balance model. Likewise, the outflow volume through sluice gates and inside the water level at the start of the outflow was initially conditioned to simulate estuary reservoir storage. The DAWAST model (Noh, 1991) was selected to simulate daily estuary reservoir inflow, wherein return flows from agricultural, domestic, and industrial water were included to simulate runoff. Using this system, the water supply capacity in the Geum River estuary reservoir was analyzed.

• Journal of Korean Institute of Industrial Engineers
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• v.39 no.3
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• pp.172-182
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• 2013

In this study we consider a flow line CONWIP system in which two types of product are produced. The processing times of each product type at each station follow an independent exponential distribution and the demands for the finished products of each type arrive according to a Poisson process. The demands that are not satisfied instantaneously are either backordered or lost according to the number of unsatisfied demands that exist at their arrival instants. For this system we develop an approximation method to obtain the performance measures such as steady state probabilities of the number of parts of each product type at each station, mean waiting times of backordered demands and the proportion of backordered demands. For the analysis of the proposed CONWIP system, we model the CONWIP system as a two class closed queueing network with a synchronization station and analyze the closed queueing network using a product-form approximation method for multiple classes developed by Baynat and Dallery. In the approximation method, each subsystem is analyzed using a matrix geometric method. Comparisons with simulation show that the approximation method provides fairly good results for all performance measures.

• Journal of Surface Science and Engineering
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• v.51 no.1
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• pp.71-78
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• 2018

This paper examines various definitions of the fourth industrial revolution and its influence on typical market demands and manufacturing methods. And this study reviewed the policies of the major global competitors in preparedness for the fourth industrial revolution. In conclusion, this paper suggested various possible developing ways in which Korean companies, especially focused on surface treatment firms, could adapt and survive in such a revolutionary industrial circumstance change.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.86-88
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• 2003

New cities and industrial complexes are being developed actively according to the government's policy. To determine the size of investment, number of power lines and substations for stable power supply to newly developed industrial complexes, the accurate estimation of power demand is necessary. "The standards for the estimation of power demands in newly developed residential and industrial complexes" established by KEPCO in 1991 have been used up to now. But the background for the estimation of power demands is weak and the accuracy has not been verified. Also, it has been passed above 10 years since their establishment and the social & economic situations have changed a lot, which requires an urgent revision. Through this survey and analysis of existing areas, new standards that will enable more accurate estimation of power demands in new cities and industrial complexes to be developed in the future are established by calculating the some kinds of power demand factors.