• Environmental and Resource Economics Review
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• v.11 no.1
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• pp.81-97
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• 2002

Unlike the existing supply-centered water policy, demand management policy of water has become an increasingly important issue in Korea. This paper attempts to analyse the demand for domestic water in Seoul. We employed Engle-Granger's error correction model(ECM) to deduced the price and income elasticities of the water demand. Particularly, we used accounted water amounts instead of supplied water amounts as representative variable of water demand. The result indicates that ECM set up is appropriate and short-run and long-run price elasticities derived by the model are -0.145 and -1.414. In contrast with other studies, we can conclude that the water demand for the water price is elastic. Besides, we can infer from this result that the water price policy with respect to a decrease of leakage ratio is more effective.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.4
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• pp.527-534
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• 2006

Demand side management(DSM) is the newly raised issues in the water resources management in recent. Many of the policy tools among demand management, the most important measures might be a pricing system. Furthermore, the responses of consumers on the price for water consumption level is the key factor for policy making. Here, we estimated panel data for 167 regions and over 7 years periods in Korea. Compare to other previous studies the price elasticities were somewhat low. The estimated price elasticity was -0.05. It was because the short term estimated period may derive lower elasticities. However, it might be a recent trend after the continuous increment of water pricing and consumers not willing to decrease their residential water consumption with increasing water pricing. According to this results, water saving effect might be much smaller than we expect with pricing policy. However, It does not imply there is no price effects on water consumption and it's still meaningful as a tool of water management.

• Journal of the Korean Operations Research and Management Science Society
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• v.29 no.3
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• pp.111-127
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• 2004

We consider a supply chain model with a make-to-order production facility and a single supplier. The model we treat here is a special case of a two-echelon inventory model. Unlike classical two-echelon systems, the demand process at the supplier is affected by production process at the production facility as well as customer order arrival process. In this paper, we address that how the demand variability impacts on the optimal replenishment policy. To this end, we incorporate Erlang and phase-type demand distributions into the model. Formulating the model as a Markov decision problem, we investigate the structure of the optimal replenishment policy. We also implement a sensitivity analysis on the optimal policy and establish its monotonicity with respect to system cost parameters.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.258-263
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• 2006

In this study, demand side management for efficiency enhancement of district heating has been investigated. Objectives of demand side management of district heating are classified and analyzed. Foreign and domestic examples are studied. Evaluation methods of demand side management of district heating are studied. Applications and expected effect of the results are presented. Finally directions for demand side management of district heating efficiency enhancement are suggested.

• Journal of the Korean Operations Research and Management Science Society
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• v.30 no.1
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• pp.17-26
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• 2005

There is the uncertainty of demands at each retailer in the supply chain. To satisfy customers' demand, retailer must have enough inventory. Nevertheless, stockout is occurred for some retailers. A lateral transshipment policy can be effectively used to deal with stockout. The new lateral transshipment policy, referred to service level adjustment (SLA), is suggested. The difference between SLA and previous policies is the integration of an emergency lateral 'transshipment with a preventive lateral transshipment to efficiently respond customers' demand in the proposed policy. Additionally, the service level to decide the quantity of products is considered. Simulation experiment is executed to treat stochastic factors in the two-echelon supply chain. The proposed policy can reduce total cost and is more effective to the change of demand, penalty cost, and ordering cost than the currently used policies.

• Health Policy and Management
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• v.27 no.1
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• pp.18-29
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• 2017

Background: In Korea, the problem of physician workforce imbalances has been a debated issue for a long time. This study aimed to draw key lessons and policy implications to Korea by analyzing projection models of physician demand/supply among five countries. Methods: We adopted theoretical framework and analyzed detail indicators used in projection models of demand/supply comparatively among countries. A systematic literature search was conducted using PubMed and Google Scholar with key search terms and it was complimented with hand searching of grey literature in Korean or English. Results: As a results, Korea has been used a supply-based traditional approach without taking various variables or environmental factors influencing on demand/supply into consideration. The projection models of USA and Netherlands which considered the diversity of variables and political issues is the most closest integrated approach. Based on the consensus of stakeholder, the evolved integrated forecasting approach which best suits our nation is needed to minimize a wasteful debate related to physician demand/supply. Also it is necessary to establish the national level statistics indices and database about physician workforce. In addition, physician workforce planning will be discussed periodically. Conclusion: We expect that this study will pave the way to seek reasonable and developmental strategies of physician workforce planning.

• Journal of the Korea Safety Management & Science
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• v.16 no.4
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• pp.323-330
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• 2014

Various inventory control theories have tried to modelling and analyzing supply chains by using quantitative methods and characterization of optimal control policies. However, despite of various efforts in this research filed, the existing models cannot afford to be applied to the realistic problems. The most unrealistic assumption for these models is customer demand. Most of previous researches assume that the customer demand is stationary with a known distribution, whereas, in reality, the customer demand is not known a priori and changes over time. In this paper, we propose a reinforcement learning based adaptive echelon base-stock inventory control policy for a multi-stage, serial supply chain with non-stationary customer demand under the service level constraint. Using various simulation experiments, we prove that the proposed inventory control policy can meet the target service level quite well under various experimental environments.

• Journal of the Korea Safety Management & Science
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• v.8 no.3
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• pp.115-123
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• 2006

The main focus of this study is to investigate the performance of a clark-scarf type multi-echelon serial supply chain operating with a base-stock policy and to optimize the inventory levels in the supply chains so as to minimize the systemwide total inventory cost, comprising holding and backorder costs as all the nodes in the supply chain. The source of supply of raw materials to the most upstream node, namely supplier, is assumed to have an infinite raw material availability. Retailer faces random customer demand, which is assumed to be stationary and normally distributed. If the demand exceeds on-hand inventory, the excess demand is backlogged. Using the echelon stock and demand quantile concepts and an efficient simulation technique, we derive near optimal inventory policy. Additionally we discuss the derived results through the extensive experiments for different supply chain settings.

• Industrial Engineering and Management Systems
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• v.8 no.1
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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.

• Health Policy and Management
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• v.17 no.3
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• pp.106-128
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• 2007

The Korean health care system is under great controversy. Over the last 30 years, main goal of health policies was to pursue equal access of health care services. However, another goal of health policies laid on efficiency and Quality of care, it had lower priorities. Superficially, controversy stems from priority setting among goals of health care system, equity, efficiency and quality. At a deeper level, arguments arise from disagreement and confusion about the values of Korean health care system. One of the value spectrums believes that health care is the basic right of human beings, therefore it should be produced and distributed on need approach, and needs are known to be decided by professionals. If we accept need approach, health care is a pubic good. Another value of spectrums considers that health care should be distributed on demand approach. Demand approach means that health care is a consumption good on the positive economics, while normative judgement believes that health care is a public good. In equity aspect, health care is considered as a public good. Over the last several years, some of scholars proposed health care reform based on the principle of competition which is based on demand approach. Others argue that the competition principle based on demand approach is not appropriate for the reform proposal, because health care has to be approached on need base. If we do not make explicit values we should adopt, consensus building for reform is nearly impossible. From this perspective, this article will review an ideology and reality in health policies in Korea.