• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권8호
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• pp.2736-2750
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• 2022

As demands for the maritime communications increase, a variety of functions and information are required to exchange via elements of maritime systems, which leads communication traffic increases in maritime frequency bands, especially in VHF (Very High Frequency) band. Thus, effective resource management is crucial to the future maritime communication systems not only to the typical terrestrial communication systems. VHF data exchange system (VDES) enables to utilize more flexible configuration according to the communication condition. This paper focuses on the VDES communication system among VDES terminals such as shore stations, ship stations and aids to navigation (AtoN) to address efficient resource allocation. We propose a resource management method considering a MIMO (Multiple Input Multiple Output) technique in VDES, which has been widely used for modern terrestrial wireless networks but not for marine environments by scheduling the essential communication resources. We introduce the general channel model in marine environment and give two metrics, spectral and the energy efficiencies to examine our resource scheduling algorithm. Based on the simulation results and analysis, the proposed method provides a possibility to enhance spectral and energy efficiencies. Additionally, we present a trade-off relationship between spectral and energy efficiencies. Furthermore, we examine the resource efficiencies related to the imperfect channel estimation.

• 보건행정학회지
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• 제22권1호
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• pp.65-84
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• 2012

Because of the rising healthcare costs, there is a growing need for developing efficiency indicators for medical resources use and measuring efficiency of healthcare providers and healthcare systems using them. In this study, we aimed to develop efficiency indicators for medical resources use by means of Delphi technique. We systematically reviewed the existing measures of medical resource use. Thirty nine indicators were selected as a candidates across the six domains: medical personnel, medical equipment, medical facilities, ethical management, resource efficiency, and drug use. To develop efficiency indicators with professional consensus, a 2-round Delphi survey was conducted among 29 professional experts. The following indicators were selected based on the Delphi survey results: adjusted number of the patient per day and level of the nurse number medical personnel in medical personnel domain; the number of the scan a professional physician and the quality of the scan in medical equipment domain; bed utilization rate in medical facility domain; drug price reported pharmaceutical price by medical institutions, medical fee billing transparency, and medical care appropriateness in ethical management domain; costliness index in resource efficiency domain; and utilization of high cost drug and items per prescription in drug use domain. The efficiency indicators could provide valid information about efficiency of healthcare providers and healthcare systems with respect to their resources use and facilitate policies to improve their efficiency.

• 보건행정학회지
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• 제10권4호
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• pp.75-98
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• 2000

This study applied Data Envelopment Analysis(DEA) and Ratio Analysis and Regression Analysis to a set of Korean Public Corporation Medical Centers to evaluate their relative human resource efficiencies. The output measure used in this study was based on health insurance system which was used in both in-patient departments and out-patient departments. Inputs included working time of the doctors, nurses, technicians, and managerial department staff. Based on the data provided on the inputs and outputs, the analysis showed 23 of the 34 hospitals to be relatively inefficient. Each hospital with an efficiency rating of less than 1 was considered relatively inefficient. In addition, managerial strategies based on dual variables were constructed to indicate the manner In which inefficient hospitals may be made efficient. A subsequent analysis of t-test revealed that the bed occupancy rate, medical revenue per 100beds, value added revenue per staff, medical revenue per staff were statistically significant. The results of this study suggest the DEA is a promising tool for evaluating relative human resource efficiency in hospitals which have multiple inputs and outputs and where the efficient production function is not specifiable with any precision. But it is considered that efficiency evaluations may be most effective]y accomplished by Incorporating a combination of methodologies such as ratio analysis and regression analysis.

• 한국유기농업학회지
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• 제19권spc호
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• pp.87-91
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• 2011

Eco-efficiency which is calculated by dividing economic productivity by the environmental load was made by synthesizing eco and efficiency from ecology and economy, proposed by World Business Council for Sustainable Development in 2000. Eco-efficiency by connection of resource efficiency with resource intensity is used as an indicator for evaluating green growth for minimizing the impact on the environment and achieving economic development as well by means of efficient use of resources. This research analyzes eco-efficiency with the case of organic agriculture promoted as a key green growth policy. Thirty questionnaires for farmers producing organic rice in Hongseong-gun, Choongcheongnam-do were used for the analysis. Eco-efficiency was measured by means of the amount of used nitrogen with respect to the amount of income, and was represented that organic agriculture was 32.0 higher than conventional agriculture. The analytical result of technical efficiency, using the (Data Envelopment Analysis (DEA) model showed that it is 0.765 which has a possibility of 21% in management improvement, and higher eco-efficiency was with higher technical efficiency. The analytical results showed that an organic agriculture contributes to green growth more than conventional agriculture. In addition, higher technical efficiency groups exhibited higher eco-efficiency indices.

• 한국병원경영학회지
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• 제12권1호
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• pp.51-74
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• 2007

This study applied Data Envelopment Analysis to a set of Korean Public Corporation Medical Centers and Japanese Municipal Hospitals to compare their relative human resource efficiencies. Based on the data provided on the inputs and outputs, the analysis showed Japanese municipal hospitals were relatively efficient than Korean hospitals. The result of analysing BCC model shows 5 hospitals in Japan and 7 in Korea with an efficiency rating of less than 1 as considered relatively inefficient. For the inefficient hospitals the manner in which inefficient hospitals may be made efficient were indicated by the managerial strategies based on dual variables. A subsequent analysis of Wilcoxon rank-sum test revealed that the medical revenue per medical expense, labor cost per value added revenue were statistically significant between efficient and inefficient Korean hospitals and medical revenue per medical expense, labor cost per value added revenue, bed occupancy rate, average length of stay, rate of personnel expenses per medical revenue were statistically significant between efficient and inefficient Japanese hospitals.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권11호
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• pp.4387-4404
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• 2015

The energy-efficient design of sensing-based spectrum sharing of a multi-input and multi-output (MIMO) cognitive radio (CR) system with imperfect multiple antenna spectrum sensing is investigated in this study. Optimal resource allocation strategies, including sensing time and power allocation schemes, are studied to maximize the energy efficiency (EE) of the secondary base station under the transmit power and interference power constraints. EE problem is formulated as a nonlinear stochastic fractional programming of a nonconvex optimal problem. The EE problem is transformed into its equivalent nonlinear parametric programming and solved by one-dimension search algorithm. To reduce searching complexity, the search range was founded by demonstration. Furthermore, simulation results confirms that an optimal sensing time exists to maximize EE, and shows that EE is affected by the spectrum detection factors and corresponding constraints.

• 자원ㆍ환경경제연구
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• 제9권5호
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• pp.811-827
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• 2000

Since improved thermal efficiency reduces capacity requirements and energy costs, electricity producers often treat thermal efficiency as a measure of management or economic performance. The conventional measure of the thermal efficiency of a fossil-fuel generation system is the ratio of total electricity generation to the simple sum of energy inputs. As a refined approach, we present a novel thermal efficiency measure using the concept of the Divisia index number. Application of this approach to the Korean power sector shows improvement of thermal efficiency of 1.1% per year during 1970-1998. This is higher than the 0.9% improvement per year given by the conventional method. The difference is attributable to the effect of fuel substitution. In the Divisia decomposition context, we also show the limitations of the popular $T{\ddot{o}}rnqvist$ index formula and the superiority of the Sato-Vartia formula.

• Reproductive and Developmental Biology
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• 제28권1호
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• pp.7-12
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• 2004

This study was performed to establish the effective culture condition for the establishment of clonal lines from porcine fetal fibroblast cells. Fibroblasts derived from a pig fetus (Day 50) were cultured and passaged two times before use. A single cell was seeded in 96-well plates, cultured in medium supplemented with different concentrations of FBS, catalase or $\beta$-mercaptoethanol ($\beta$ME), and classified by cell size and morphology. Cells were passaged two times into 4-well dish before freezing. The establishment efficiencies were not different among different concentrations of FBS (0.3 to 5.1%). However, population doubling time (PDT) was significantly decreased by increasing the FBS concentration (P＜0.05). The establishment efficiency of $\beta$ME-added group (10.4%) was significantly higher than those of catalase-added and control groups (3.5%, and 3.5%, respectively, p＜0.05), and PDT was significantly decreased (23.6 vs 28.1, and 25.5 h, respectively, p＜0.05). However, catalase did not show a positive effect on the establishment efficiency. Cell size and morphology did not affect the establishment efficiency and PDT of clonal lines. The result of present study shows that the establishment efficiency of clonal cell lines can be enhanced by the culture in media supplemented with 30% FBS and $\beta$ME.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권1호
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• pp.1-19
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• 2015

With the recent popularity of smart terminals, the demand for high-data-rate transmission is growing rapidly, which brings a new challenge for the traditional cellular networks. Both device-to-device (D2D) communication and small cells are effective to improve the transmission efficiency of local communication. In this paper, we apply D2D communication into a small cell network system (SNets) and study about the optimization problem of resource allocation for D2D communication. The optimization problem includes system scheduling and resource allocation, which is exponentially complex and the optimal solution is infeasible to achieve. Therefore, in this paper, the optimization problem is decomposed into several smaller problems and a hierarchical scheme is proposed to obtain the solution. The proposed hierarchical scheme consists of three steps: D2D communication groups formation, the estimation of sub-channels needed by each D2D communication group and specific resource allocation. From numerical simulation results, we find that the proposed resource allocation scheme is effective in improving the spectral efficiency and reducing the outage probability of D2D communication.

• 지역과문화
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• 제6권2호
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• pp.77-104
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• 2019

본 연구는 지역 문화 생태계의 전제가 되는 지역문화자원에 대한 지방자치단체의 활용 효율성을 분석하고자 하였다. 이를 위해 자료포락분석(DEA)을 통해 전국 17개 광역시·도의 상대적인 효율성을 측정하였다. 이와 더불어 지역문화자원 환경 관련 산출 변수를 포함하여 '전체 효율성'을 도출하고, 앞서 도출한 '활용 효율성'과 비교하여 지역문화자원 '환경 효율성'이 지자체의 효율성 순위 변동에 미치는 영향을 추정하였다. 분석 결과, 17개 광역시·도 중 5곳의 기초자치단체들이 효율적으로 지역문화자원을 활용한 것으로 평가되었으며, 비효율적인 광역시·도의 기초자치단체들은 순기술효율성 보다 규모의 비효율이 상대적으로 영향을 미치고 있음을 확인하였다. '환경 효율성' 추정 결과, 17개 광역시·도의 '활용 효율성'과 '전체 효율성' 순위가 동일한 곳은 없었으며, '전체 효율성'의 순위 증감을 통해 '환경 효율성'의 영향을 확인하였다. 지방자치단체의 효율성 차이는 투입 변수에 전제된 인구밀도가 큰 영향을 미치기 때문에, 향후 효율성을 개선하기 위해서는 지역문화자원 활용의 주요 수요자인 지역주민 인구 추계에 따라 투입의 적정 수준을 조절해야 할 필요가 있다. 더불어 현재 지방자치단체에서 개최하고 있는 지역축제, 마을축제의 점검을 통해 비효율적인 부분을 제거하여 산출량을 질적으로 개선해야 한다. 또한 지방자치단체의 지역문화자원 효율성을 분석하고자 할 때, 환경적 산출 요인의 고려가 함께 충분히 이루어져야 한다.