• 상하수도학회지
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• 제23권1호
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• pp.57-67
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• 2009

Under the supply-oriented policy, efficiency and rationale have not been fully considered in planning of water supply facilities in Korea. As a case, this study shows that large-size systems are suffering from overcapacity problem of water treatment plants, and thus discusses what options should be applied to deal with inefficiency. Water demand of large-size systems has suddenly decreased for the last 10 years while water demand has been often assumed to increase at a regular rate in planning of plants according to excess capacity hypothesis. This inconsistency led to a serious overcapacity. In 2006, total excess capacity of nine large-size systems was more than 1.2 times as large as maximum daily demand of total customers in Seoul. However, their options are expected to stay ex post facto. To prepare the risk of overcapacity, and draw large benefits out of the plants, the authors and other professionals in Korea should further discuss the more adaptive method for prediction of water demand, and systems integration between a large-size system and adjoining systems.

• 한국유기농업학회지
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• 제28권2호
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• pp.171-188
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• 2020

The Coronavirus disease (COVID-19), first identified in China in December 2019, has widely spread worldwide and is an ongoing pandemic. It is expected that the ripple effect of COVID-19 on the global economy including the agricultural sector will increase substantially if not properly controlled shortly. This study examines the potential impact of COVID-19 on the Korean beef cattle sector and farm labor demand for Korean beef cattle using a dynamic partial equilibrium model. The agricultural production value and farm labor demand for Korean beef cattle in the scenario assuming pessimistic GDP growth rate (-1.2% in 2020) with no direct supply shocks fell by up to 4.00% and 0.67%, respectively, compared to the baseline which represents the future without COVID-19 outbreak. On the other hand, the agricultural production value and farm labor demand for Korean beef cattle in the scenario assuming both pessimistic GDP growth rate and supply shocks (-12.7% beef imports and + 2.4% feed cost in 2020) increased by up to 12.08% and 1.99%, respectively, compared to the baseline.

• 토지주택연구
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• 제9권3호
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• pp.9-18
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• 2018

Administrative city has been developed step by step aiming to being a public transport-oriented new city. In spite of its primary goal, administrative city is dominated by car-oriented tansportaion system because the supply of public transportation has not been adequately and timely performed. In this study, we investigate the current situation related to (public) transportation use in administrative city. Also, we examine the issues of traffic system through a survey on residents' consciousness about public transportation use. Additionally, the analysis of demand elasticity according to the change of the conditions of using public transportation and passenger car is conducted for passenger car users. As a result, it is analyzed that as the neighborhood is more stabilized after the completion of development the resistance to the abandonment of passenger car is higher when the tide demand control method is introduced. Therefore, it is concluded that pre-emptive public transportation supply and the management of car demand management are necessary for the activation of public transportation in Administrative city.

• Industrial Engineering and Management Systems
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• 제8권1호
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• pp.1-13
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• 2009

This paper presents a coordinated planning model of price-dependent demand for a single-manufacturer and a single-retailer. The demand is assumed to be normally distributed, with its mean being price dependent. The manufacturer and retailer coordinate with each other to jointly and simultaneously determine the retail selling price and the retailer order quantity to maximize the joint expected total profit. This model is then compared to a 'returns' policy model where manufacturer buys back unsold items from the retailers. It is shown that the optimal total profit is higher for coordinated planning model than that for the returns policy model, in which the retail price is set by the retailer. A compensation or profit sharing scheme is then suggested and it is shown that the coordinated model with profit sharing yields a 'win-win' situation. Numerical results are presented to illustrate the profit patterns for both linear and nonlinear demand functions. The coordinated planning model, in addition, has a lower optimal price than for a returns policy model, which would result in higher sales, thus expanding the markets for the whole supply chain.

• 산업공학
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• 제22권4호
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• pp.368-375
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• 2009

This paper considers a two-stage supply system consisting of two make-to-stock facilities. The facility in the first stage produces a single type of component in anticipation of future demands from the market and the end item production while the facility in the second stage produces the end item in anticipation of future demands from the OEM customers. The facility in the first stage has the option of to accept or reject each incoming demand from the market. In this paper, we address the problem of how to control the exogenous component demand and how to manage the production of the end item and the component so as to maximize the system's profit subject to the system costs. In this paper, we present a heuristic policy that is the base-stock production policy combined with a linear switching curve for component demand control. Numerical study is implemented under different operating conditions of the system and it shows that the performance of the heuristic is very promising compared to that of the optimal policy for the Markov model.

• International Journal of Advanced Culture Technology
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• 제8권2호
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• pp.270-276
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• 2020

In this paper, we analyze the buyer's joint pricing and lot-sizing model in a two-stage supply chain consisting of the supplier, the buyer and the customer. It is assumed that the supplier will permit a certain fixed period for settling the amount the buyer owes to him for the items supplied in order to stimulate the demand for the product. Generally, credit transactions would have a positive effect to the buyer. The availability of credit transactions from the supplier effectively reduces the cost of holding stocks for the buyer and therefore, the buyer has a lot of price options to choose his sales price for a customer in anticipation of increased the customer's demand and, as a result, it will appear to increase the buyer's inventory levels. On the other hand, in the case of decaying products in which their utility decay over time, the decaying rate with time may be expected to reduce inventory levels. In this regard, we need to analyze how much the length of credit period and the decaying rate affect the buyer's pricing and lot-sizing policy. For the analysis, we consider the situation where the customer's demand is represented as a linearly decreasing function of the buyer's sales price. From this perspective, we formulate the buyer's annual net profit and analyze the effect of the length of credit period and decaying rate of the product on the buyer's inventory policy numerically.

• 보건행정학회지
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• 제29권4호
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• pp.482-495
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• 2019

Background: An important function of the regional public hospital is to satisfy the basic medical needs of the community through the stable provision of high-quality medical services. The purpose of this study was to identify the relevance index (RI) of the regional public hospital and to identify the factors that affect the RI. Methods: Data were obtained from the 2017 regional public hospital operation evaluation report and 2017 medical monitoring report for vulnerable area. RI of the regional public hospital was a dependent variable, and multiple regression analysis was performed with observed variables of medical supply-demand condition, medical supply, and medical supply structure. Direct effects and indirect effects were confirmed by the analysis of structural equation models (SEM) to see if there were mediating effects. Results: The RI was 13.1%, and the average of all percentage refined diagnosis-related group (RDRG) was 29.4%. Factors affecting RI were medical supply-demand conditions, medical supply, and medical supply structure. As a result of multiple regression analysis, RI was higher when high percentage RDRG of the regional public hospital (t=4.117, p<0.05), the size of regional public hospital location (t=-2.554, p<0.05), and the population of regional public hospital location (t =-2.415, p<0.05) were smaller. The results of the SEM analysis show that the higher the medical supply-demand conditions, the more direct effect of decreasing the RI and the indirect effect of decreasing the effect of reduction through the medical supply (direct effect=-1.322, total effect=-0.573, p<0.01). The higher the medical supply structure, the more direct effect on the RI (direct effect=1.047, p<0.05) and the higher the medical supply, the more indirect effect of RI through the medical supply structure (total effect=direct effect=0.619, p<0.05). Conclusion: It has been confirmed that the provision of medical services can affect the RI the regional public hospital which should be considered in carrying out future policies.

• 한국정보시스템학회지:정보시스템연구
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• 제24권2호
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• pp.73-96
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• 2015

Purpose Information security industry is rapidly growing, but has been confronted with many challenges in a business environment. One of them is the imbalance between supply and demand of information security manpower, which has caused an insecure market situation. Therefore, this study has derived factors of promoting and hindering information security manpower from governance, academics, corporations, and workforce perspectives, and has analyzed a sequence of cause and effect of each factor. Design/methodology/approach This study is an exploratory research based on the interviews. The causal loop diagram (CLD) was developed to deduce key issues and propose alternatives. Findings The result of this study is expected to help the development of information security manpower in Korea, by minimizing the potential negative effects as well as maximizing the positive effects. This study found out the dynamic causes and effects of the security manpower system in each stakeholder's perspective. The cause-and-effect relationships between the stakeholders will be able to contribute to solve the imbalance of supply and demand in security manpower system.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.451-458
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• 2017

An Electric Vehicle (EV) is operated with the electric energy of a battery in place of conventional fossil fuels. Thus, a suitable charging infrastructure must be provided to expand the use of electric vehicles. Because the battery of an EV must be charged to operate the EV, expanding the number of EVs will have a significant influence on the power supply and demand. Therefore, to maintain the balance of power supply and demand, it is important to be able to predict the numbers of charging EVs and monitor the events that occur in the distribution system. In this paper, we predict the hourly charging rate of electric vehicles using transformation matrix, which can describe all behaviors such as resting, charging, and driving of the EVs. Simulation with transformation matrix in a specific region provides statistical results using the Monte-Carlo Method.

• 한국정보시스템학회지:정보시스템연구
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• 제15권3호
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• pp.159-174
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• 2006

Employment rate of graduating students has been one of the most important issues at universities. Recently interest on internship abroad has been increased significantly due to globalization of the society In particular, central and local governments have developed policies and encouraged university students to participate in internships abroad. However, activities and resources for internships abroad are very limited to a few organizations. This paper investigated the current status of internship in the U.S. and Korea. Then, this paper analyzed differences in demand and supply of the internship and matching mechanism of the internship between the U.S. and Korea. From the results of those analyses, this paper developed an international network model which can help effective and efficient increase in the demand and supply of the internship as well as the internship matching mechanism in Korea. This network model utilizes international NGOs in order to develop internationally cooperative environment. This model provides mechanism for (1) effectively identifying intern applicants who like to work abroad and evaluating thent (2) effectively identifying new internship positions and evaluating companies which plan to hire interns, (3) efficiently matching demand for and supply of internship by identifying appropriate candidates, (4) monitoring companies for their quality of working conditions and interns for their qualities of work This model for internship has been applied for a NGO which is International CBMC (Christian Businessman Committee International)