• Journal of the Korea Safety Management & Science
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• v.8 no.5
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• pp.139-150
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• 2006

The aim of this study is to establish an efficient distribution planning for a capacitated multi-stage supply chain. We assume that the demand information during planning horizon is given a deterministic form using a certain forecasting method. Under such a condition, we present a cost effective heuristic method for minimizing chain-wide supply chain inventory cost that is the sum of holding and backorder costs by using look-ahead technique. We cope with the capacity restriction constraints through look-ahead technique that considers not only the current demand information but also future demand information. To evaluate performance of the proposed heuristic method, we compared it with the extant research that utilizes echelon stock concept, under various supply chain settings.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.1
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• pp.20-24
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• 2008

A bid-based pool(BBP) model is representative of energy market structure in a number of restructured electricity markets. Supply function equilibrium(SFE) models of interaction better match what is explicitly required in the bid formats of typical BBP markets. Many of the results in the SFE literature involve restrictive parametrization of the bid cost functions. In the SFE models, two parameters, intercept and slope, are available for strategic bidding. This paper addresses the realistic competition format that players can choose both parameters arbitrarily. In a fixed demand function, equilibrium conditions for generation company's profit maximization have a degree of freedom, which induces multi-equilibrium. So it is hard to choose a convergent equilibrium. However, consideration of stochastic demand function makes the equilibrium conditions independent each other based on the amount of variance of stochastic demand function. This variance provides the bidding players with incentives to change the slope parameter from an equilibrium for a fixed demand function until the slope parameter equilibrium.

• Journal of Korean Society of Water and Wastewater
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• v.8 no.2
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• pp.35-42
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• 1994

This study is to analyse probability distribution characteristics of water supply demand. Two cities located near Seoul were selected as study areas. In this study, two probalility distribution types were tested using the K-S(Kolmogorov-Smirnov) method. The K-S method was used to prove the goodness of the selected distribution type. And also, the goodness of maximum day demand to average day demand ratio which was obtained by field data was tested. Conclusions are as follows. 1.Bothl normal distribution type and lognormal distribution type are appropriate as the probalility distribution type for the water supply demand. 2. The probability distribution characteristics can be used to test the goodness of the maximum day to average day demand ratio.

• Journal of the Korea Safety Management & Science
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• v.11 no.1
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• pp.205-211
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• 2009

In reality, distribution planning for a supply chain is established using a certain probabilistic distribution estimated by forecasting. However, in general, the demands used for an actual distribution planning are of deterministic value, a single value for each of periods. Because of this reason the final result of a planning has to be a single value for each period. Unfortunately, it is very difficult to estimate a single value due to the inherent uncertainty in the probabilistic distribution of customer demand. The issue addressed in this paper is the selection of single demand value among of the distributed demand estimations for a period to be used in the distribution planning. This paper proposes an efficient demand selection scheme for minimizing total inventory costs while satisfying target service level under the various experimental conditions.

• Health Policy and Management
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• v.9 no.3
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• pp.33-52
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• 1999

The purpose of this study is to project the supply and demand for nurses till the year 2012 and to make recommendations for establishment of proper policies regarding them. To predict the supply of nurses. a baseline projection and demographic methods were employed. The derivative demand was used to forecast the demand of nurses. The results of this study provide us with valuable information on nursing manpower planning for the 21th century. Specifically. results indicate that there will be an oversupply of nurses in the near future based on the current productivity. Based on the medical law. there will be an undersupply of nurses till 2002 but an oversupply after that. Thus. the active supply of nurses must be decreased. One way to achieve this would be decreasing the size of training and education. Thus. we recommend that the number of entrances to 4 year programs will be reduced 20% in 2004. and a reduction of 20% by 2005 in 3 year programs. The results of this study suggest the following: First. a manpower bank for nurses who are trying to reenter the market must be established. Second, improvement of education and retraining is needed for the quality control of nurses. Further studies should take into consideration the above factors.

• Land and Housing Review
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• v.9 no.4
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• pp.10-18
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• 2018

As the volatility increasement of the number of tourist, there was been controversy over supply-demand imbalance in hotel market. The purpose of this study is to analysis on determinants of hotel occupancy rate in Jeju Island. The quantitative method is based on cointegrating regression, using an empirical dataset with hotel from 2000 to 2017. The primary results of research is briefly summarized as follows; First, there are high relationship between total hotel occupancy rate and hotel occupancy of foreign tourist. The volatility of hotel occupancy is caused by foreigner user than local tourists though local tourist high propotion of hotel occupancy in Jeju Island. Second, hotel occupancy of local tourist has not relationship with demand and supply variables. Because some hotel users are not local tourists but local resident, and effects to other variables of hotel consumer trend, accommodation such as Guest house, Airbnb. Third, there are high relationship between foreign hotel occupancy rate and demand-supply variables. These research imply that total management of supply-demand is very important to seek stability of hotel occupancy rate in Jeju Island. Also it can provide a useful solution regarding mismatch problem between supply-demand as well as development the systematic forecasting model for hotel market participants.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2B
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• pp.228-239
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• 2004

Information Security industry in Korea is growing rapidly but is confronted with many challenges in business environment. One of the worst hardships is the mismatch in the demand and supply of manpower. Thus the government is developing a manpower policy to relieve the situation. To suggest policy implications, this study analyzes the demand and supply of Information Security manpower in the systematic and behavioral point of views. Using System Dynamics approach, we formulate a model to analyze the demand and supply of Information Security manpower. Finally we simulate the model and interpret the results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.5C
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• pp.642-653
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• 2004

Information Security industry in Korea is growing rapidly but is confronted with many challenges in business environment. One of the worst hardships is the mismatch in the demand and supply of manpower. Thus the government is developing a manpower policy to relieve the situation. To suggest policy implications, this study analyzes the demand and supply of Information Security manpower in the systematic and behavioral point of views. Using System Dynamics approach we formulate a model to analyze the demand and supply of Information Security manpower. Finally we simulate the model and interpret the results.

• Journal of the Korea Safety Management & Science
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• v.9 no.1
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• pp.175-186
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• 2007

The employment permit system for foreigners, which stresses introduction of foreign work force in a legal manner rather than in the position of being trainees, is anticipated to efficiently improve introduction and the overall management system of foreign work force and related difficulties such as illegal alien problems, absurdity on sending laborers overseas. In this paper, a prospective model of supply and demand of work force has been developed basing on various categories of industries and patterns about nationally practical foreign employees to look over efficient supply and demand of work force suiting employment of foreigner among foreign work force policies. To propose the prospective model, we have derived industry- and pattern-related matrixes of foreign laborers basing on Inter-Industry Analysis Method put forth by Professor Leontiyef in 1930, and through the derived matrix assessed repercussions concerning overall domestic industries and foreigner types and decided yearly weight; the capacity of supply and demand of foreign laborers can be compared through proposed statistical estimation and government estimation by combining the determined weight with yearly incomes of foreign laborers. This paper has thoroughly considered the particularity of our employment permit system for foreigners and applied the Weibull distribution and incorporated the dependence of foreign laborers during the limited period of 3 years to the industry relation analysis, ultimately proposing an efficient supply and demand method about domestic foreign work force.

• Journal of Electrical Engineering and Technology
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• v.12 no.4
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• pp.1427-1434
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• 2017

Since the late 2000s, there has been growing preparation in South Korea for a sudden reunification of South and North Korea. Particularly in the power industry field, thorough preparations for the construction of a power infrastructure after reunification are necessary. The first step is to estimate the peak load demand. In this paper, we suggest a new peak demand estimation methodology by integrating existing correlation analysis methods between economic indicators and power generation quantities with a power supply interruption model in consideration of power consumption patterns. Through this, the potential peak demand and actual peak demand of the Nation, which experiences power supply interruption can be estimated. For case studies on North Korea after reunification, the potential peak demand in 2015 was estimated at 5,189 MW, while the actual peak demand within the same year was recorded as 2,461 MW. The estimated potential peak demand can be utilized as an important factor when planning the construction of power system facilities in preparation for reunification.