• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.3
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• pp.1164-1183
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• 2019

The rapid development of cloud computing and high requirements of operators requires strong support from the underlying Data Center Networks. Therefore, the effectiveness of using resources in the data center networks becomes a point of concern for operators and material for research. In this paper, we discuss the online virtual-cluster provision problem for multiple tenants with an aim to decide when and where the virtual cluster should be placed in a data center network. Our objective is maximizing the total revenue for the data center networks under the constraints. In order to solve this problem, this paper divides it into two parts: online multi-tenancy scheduling and virtual cluster placement. The first part aims to determine the scheduling orders for the multiple tenants, and the second part aims to determine the locations of virtual machines. We first approach the problem by using the variational inequality model and discuss the existence of the optimal solution. After that, we prove that provisioning virtual clusters for a multi-tenant data center network that maximizes revenue is NP-hard. Due to the complexity of this problem, an efficient heuristic algorithm OMS (Online Multi-tenancy Scheduling) is proposed to solve the online multi-tenancy scheduling problem. We further explore the virtual cluster placement problem based on the OMS and propose a novel algorithm during the virtual machine placement. We evaluate our algorithms through a series of simulations, and the simulations results demonstrate that OMS can significantly increase the efficiency and total revenue for the data centers.

• Korea Journal of Hospital Management
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• v.13 no.4
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• pp.1-26
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• 2008

This study examines the statistical relationship between medical specialists and managerial performance, using regression analysis with the number of medical specialists per 100 beds as the independent variable and the managerial performance index as the dependent variable. Managerial performance index incorporated the number of out-patients per specialist, the number of in-patients per specialist, the volume of revenue per specialist, the number of beds per specialist, and the average length of stay. To compare different groups of hospitals, dummy variable was applied to five groups of hospitals according to size: 100-299 beds, 300-599 beds, 600-899 beds, 900-1199 beds, and more than 1200 beds. The data consisted of 181 general hospitals with more than 100 beds, which included 28 public hospitals, 73 corporate hospitals, 64 university hospitals and 16 private hospitals. Of those, 87 hospitals were located in big cities and 94 hospitals in medium to small cities. This study used hospitals from the Korean Hospital Association, and data published in 2004. The collected data sample was analyzed using the SPSSWIN 12.0 version, and the study hypothesis was tested using regression analysis. The findings of this study are summarized as follows: Hypothesis 1 predicting a negative effect of the number of medical specialists on the number of out-patients per specialist was supported with statistical significance. The analysis of dummy variable showed causality in all the hospital groups larger than the group of 100-299 beds. Hypothesis 2 predicting a negative effect of the number of medical specialists on the number of in-patients per specialist was supported with statistical significance. The analysis of dummy variable showed causality in the hospital group of 300-599 beds when compared to the group of 100-299 beds. Hypothesis 3 predicting a negative effect of the number of medical specialists on the volume of revenue per specialist was not supported. However, the analysis of dummy variable showed that the volume of revenue per specialist increased in the hospital groups of 600-899 beds, 900-1199 beds, and over 1200 beds, when compared to the group of 100-299 beds. Hypothesis 4 predicting a negative effect of the number of medical specialists on the average length of stay was supported with statistical significance. The analysis of dummy variable showed causality in the hospital group of 300-599 beds, when compared to the group of 100-299 beds. Results of this study show that the number of the medical specialists per 100 beds is an important factor in hospital managerial performance. Most hospitals have tried to retain as many medical specialists as possible to keep the number of patients stable, to ensure adequate revenue, and to maintain efficient managerial performance. Especially, the big hospitals with greater number of beds and medical specialists have shown greater revenue per medical specialist despite the smaller number of patients per medical specialist. Findings of this study explains why hospitals in Korea are getting bigger.

• Korea Journal of Hospital Management
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• v.11 no.4
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• pp.82-103
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• 2006

The purpose of this study is to analyse statistically the relation between medical service quality and managerial performance. And then the way of analysis is the regression analysis that independent variable is service quality, dependent variable is the volume of revenue, the number of patients and the rate of beds utility, and dummy variable is the number of beds, ownership and region. The sample hospitals were the 113 hospitals on general hospitals more than 300beds which were consisted of 20 public hospitals, 41 corporate hospitals and 52 college hospitals, and also distributed 67 hospitals on big city and 46 hospitals other city. The sample hospitals were selected from the Korean Hospital Association and the data of the year 2003 and 2004. The collected data was analyzed using the SPSSWIN 10.0 version, and the study hypothesis was tested using regression analysis. The findings of this study are summarized as follows. First, as a result of analysing hypothesis 1. In the study of the relationship between the service quality and the revenue, it was verified that the more service quality in last year became the more revenue in the year. But the dummy variable, ownership and region, rarely related to hospital revenue. Therefore it means that the more service quality is connected to the more revenue on the large number of beds hospitals. Second, as a result of analysing hypothesis 2 & 3. In the study of the relationship between the service quality and the number of patients, it was verified that the more service quality in last year became the more outpatients in the year. But there was no verified to inpatients. It seems to be the reason why a hospital has operated the fixed number of beds approved by the public office. So there are no free to expand beds according to the number of inpatients as much as inpatients are increasing. Third, as a result of analysing hypothesis 4 & 5. In the study of the relationship between the service quality and the rate of beds utility, it was verified that the more service quality in last year became the shorter of average stay of length in the year. Especially it has influenced much more on a hospital which was the large number of beds, the corporate and the college, but the region. But it was denied that the more service quality became the more the beds turnover. As a result of this study, it shows that the service quality in the last year has importantly influenced on a hospital managerial performance in the year. Estimating the service quality of each hospital, most patients have selected the hospital they want. And the hospital need to keep the number of patients for the proper management. So this result of the study means that a hospital must improve the service quality for keeping efficient management.

• Environmental and Resource Economics Review
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• v.18 no.4
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• pp.767-785
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• 2009

This paper studies the effect of industrial waste water effluent charge reform. The goal of the present effluent charge system is to use environmental resources in an efficient way by charging the cost for removing emitted water pollutants. However, the present system is a type of regulation instead of providing economic incentives to the industry. That is, if a firm emits pollutants greater than the limit, it has to pay an amount greater than the cost of cleaning them taking into account the amount of waste water discharged, region, the number of violation and the level of density of pollutants. However, the excessive fees have resulted in the lowest ratio of revenue-to-effluent charge among all environmental charges. The paper estimates the effect of the change in effluent fee and revenue when the present effluent charge system is converted to one that offers economic incentives. The results show that the amount of waste water effluent charge is about four times larger than the estimated environmental cleaning cost. In addition, the results show that by modifying the effluent charge system, the ratio of revenue to effluent charge can be raised.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.3
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• pp.237-246
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• 2021

The ILI, developed by the IWA (International Water Association), has been used in many countries as an indicator of water leakage. In Korea, the revenue water has been used as a performance indicator for waterworks although there is an opinion to replace it with the ILI. Hence, it has been necessary to investigate whether the ILI can replace the revenue water in Korea. The four main operating indicators (i.e., water service population, profit-loss ratio, fiscal self-reliance, and aged pipe rate) of 162 Korean waterworks were compared with the ILI with the linear regression method. Local water authorities with more than 1 million water service population, with more than 60% profit-loss ratio, more than 40% and less than 60% fiscal self-reliance, and more than 20% aged pipe rate showed meaningful correlation between the four parameters and the ILI. In the remaining cases, their correlations were little or weak. This means that using the ILI may not be an efficient method to represent the performance of the water supply system in Korea because of the lack of UARL (Unavoidable Annual Real Losses) data accuracy. To use the ILI in Korea, it will be required to carry out an additional research to accumulate reliable CARL (Current Annual Real Losses) and UARL data in the future.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.4
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• pp.85-94
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• 2015

Recently, research on the smart grid that combines ICT(Information & Communication technology) to the power system has been actively progressed. If the occupancy of the EV(Electric vehicle) is increased. the V2G(Vehicle to grid) system is available which constitutes the micro-grid through battery of EV. V2G system performs load leveling and efficient energy consumption by battery operation considering load condition. But, if the battery is used only depending on the electricity rates, it doses not consider the life of the battery. The ACC(Achievable cycle) and the total transferable energy of battery varies corresponding to the selected DOD(Depth of discharge). In this paper, the optimal DOD selection method of V2G system considering battery wear cost and average driving distance of EV. Also, the total revenue prediction of various nation is presented considering the actual electricity costs per hour.

• Korea Journal of Hospital Management
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• v.11 no.3
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• pp.73-93
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• 2006

This study aims at providing necessary informations for management decision-making to the hospital manager, such as ratios of fixed and variable cost to total operating expense, and variable cost ratio to operating revenues, and determinant factors affecting cost behavior. A study model and related hypotheses were established, data were collected from 41 private university hospitals for the 6years from 1998 to 2003, and regression analyses were performed to test the hypotheses. The results of the analyses and conclusions are as follows; First, labor cost and administration cost within the same number of beds have not only fixed quality of the cost, but variable quality of that. Also, the ratio of the variable costs to operating revenue of the metropolitan was estimated 76.9% and that of other area hospitals was 80.1%. Second, the major factors affecting the increase rate of the operating expense were the increase rates of the number of inpatients, the number of employee, and the number of hospital operating bed. This result implies that maintaining a optimal hospital bed size and efficient operation of the beds are important strategic factors of hospital management.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.04a
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• pp.451-453
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• 1995

This paper examines characteristics of the accounting rate system whereby international telecommunications carriers settle net balances of account arising from bilateral traffic flows. Using a two stage game model, we explain problems in the system: growing traffic and payment imbalances, and resulting conflicts regarding accounting rates between carriers of, say, developed and developing countries. In this paper, we view the problems as a splitting-a-pie game in which one carrier cannot get more without a loss of the other, but total pie size depends upon the accounting rate. Therefore, a natural solution should be inevitably of a Coasian-type to establish a mutual agreement. In this regard, we first derive an efficient accounting rate, in the sense that it can make both carriers better off. Next we suggest some ways of attaining the efficient outcome. Regulatory and policy implications are also discussed.

• Health Policy and Management
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• v.2 no.2
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• pp.1-32
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• 1992

The Canadian experience-universal government health insurance administeredby the ten provinces and two territories with some fiscal and policy variations-suggests the possibility of more effectve and efficient health care delivery system. The central purpose of the Canadian health in surance was to reduce and hopefully eliminate financial barriers to medical care. In this it succeeded. But it also produced varous kinds of unexpected side-effects on cost and quality. The Federal and Provincial Governments of Canada continue to exert theri efforts to ameliorate these problems. The lesson from Canada is that the health care revenue should be raised at the national level and managed at the regional level, and the regional healthcare financing organization has to take over the functions of the public health center. These alternatives is expected to make the Korean health care delivery system more efective and efficient, and to achieve health for all. This paper also discussed the policy agenda for implementing such alternatives in Korea.

• Journal of Environmental Impact Assessment
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• v.25 no.6
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• pp.487-501
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• 2016

This study aims to establish basic data of operating status for ecological learning facilities in Korea, investigate their characteristics for operating methods, and present proposals for the efficient operation and management of ecological learning facilities. For this purpose, a list of ecological learning facilities in Korea was established and 50 facilities were surveyed about the current status regarding the operation and management. Based on the survey, operation form, interpreter and volunteer, visitor, budget and revenue, promotion method, and other items were analyzed. Concerning the operating forms, most of the facilities were direct-operated facilities by government, and they are operating mainly by officials. Visitors are mostly families on weekends, while kindergarten children are main visitors during weekdays. Most facilities have higher proportion of visitors nationwide, and they get information mainly from websites operated by facilities and related organization. The annual operating budget and revenue depend on the facility size and operating forms, and the direct-operated facilities by government use higher budget compared to commission-operated ones. For the efficient operation of ecological learning, expert with specialized knowledge should participate in the operation, and intuitive and informative websites should be established and continually managed. In addition, it is necessary to support revenue of by national and local governments and to secure external funding network like local companies and donation.