• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.526-531
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• 2003

A cone cylinder is used to obtain variable operation conditions of a sonic ejector-diffuser system. The cone cylinder is movable to change the ejector area ratio, thus obtaining variable mass flow rates. The present study investigates the effects of ejector throat area ratio and operating pressure ratio on the entrainment of secondary stream. The numerical simulations are based on a fully implicit finite volume scheme of the compressible, Reynolds-Averaged, Navier-Stokes equations. The ejector throat area is varied between 3.94 and 8.05, and the operating pressure ratio is changed from 3.0 to 9.0. The results show that the entrainment ratio and mass flux ratio become more dependent on the ejector throat area ratio, when the pressure operating ratio is low. The total pressure losses produced in the present ejector system increase with the operating pressure ratio and the ejector area ratio, but for a given operating pressure ratio, the losses are not significantly dependent on the ejector area ratio when it is larger than about 5.0.

• 한국물환경학회지
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• 제28권2호
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• pp.202-212
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• 2012

Due to the deterioration of water supply network and the deficiency of raw water, the water utility of local governments have performed various projects to improve their revenue water ratio. However, it is very difficult to estimate the cost for maintaining the revenue water ratio at higher level after completing the project, because local governments have different conditions affecting the operating and maintenance cost of water supply network. The purpose of this study is to present a procedure to estimate the operating and maintenance cost required to maintain the target revenue water ratio of the water supply network. For this purpose, we estimated the cost used only for operation and maintenance of water supply network of 164 local governments with the aid of K-Mean Clustering Analysis and the data from 40 representative local governments. Then, the regression analysis was performed to find relationship between revenue water ratio and the operating and maintenance cost with two different data sets generated by two classification methods; the first method classifies the local governments by means of k-means clustering, and the other classifies the local governments according to the index standardized by the operating and maintenance cost per unit length of water mains per revenue water ratio. The results shows that the method based on the index standardized by the cost and revenue water ratio of each government produces more reliable results for finding regression equations between revenue water ratio and the operating and maintenance cost only for water supply network. The estimated regression equations for each group can be used to estimate the cost required to keep the target revenue water ratio of the local government.

• 보건행정학회지
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• 제13권3호
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• pp.129-147
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• 2003

This study is to grasp a trend of profitability classified by characteristics of hospitals and to analyze related factors. Subjects are 145 hospitals which have gotten the standardization audit by Korean Hospital Association during 1998-200l. Profitability was measured in the aspect of operation profit rate with operating margin to gross revenue as proxy variables. Independent variables were classified by general factors (ownership, number of beds, period of establishment, competition), financial factors (liabilities to total assets, current ratio, fixed ratio, total asset turnover, inventories turnover), and factors related to patient treatment (average length of stay, bed occupancy rate, new outpatient ratio, admission ratio of outpatients, number of patients per specialist, personnel costs per adjusted inpatient, administrative costs per adjusted inpatient). Hierarchical multiple regression analysis model was used in this study. As a result of hierarchical multiple regression analyzation of operating margin to gross revenue, adjustive $R^2$ of general factors was relatively more powerful. The factors had significant effect on operating margin to gross revenue were ownership(+), number of beds(+), competition(+), current ratio(+), fixed ratio(+), total asset turnover(+), personnel costs per adjusted inpatient(-).

• Journal of Biosystems Engineering
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• 제42권4호
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• pp.242-250
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• 2017

Purpose: This study was conducted to determine the appropriate operating conditions through a factorial experiment for the secondary separating part of the self-propelled pepper harvester. Methods: An experimental setup that simulates the secondary separating part of the self-propelled pepper harvester was organized. Test samples were classified into three types according to the number of peppers on a stem, and 12 sets were prepared for each type. Among the operating conditions of the secondary separating part, the rotational speed of drum B (four levels), radial clearance between drums and cylindrical teeth (three levels), and speed ratio between the three drums (two levels) were set as the test factors, and tests were repeated three times for different levels of each factor. The appropriate operating conditions were determined by analyzing the separation ratio and damage ratio of the peppers collected through the secondary separating part. Results: The test factors changed the overall separation ratio and overall damage ratio in similar trends. In other words, the conditions that caused high overall separation ratios also exhibited high overall damage ratios. Owing to the high overall damage ratio in the condition with the highest overall separation ratio, the operating conditions should be selected considering both ratios. Conclusions: When the condition with more than 60% of overall separation ratio and less than 15% of overall damage ratio was considered as the appropriate operating condition, 70 rpm of the rotational speed of drum B, 5 mm of the radial clearance between drums and cylindrical teeth, and 7:3:5 for the speed ratio of the three drums A, B, and C should be applied for the secondary separating part used in this study. Supplementary studies will be required in the future to find optimal operating conditions through the actual field test under further divided test factors.

• 대한예방한의학회지
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• 제18권1호
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• pp.43-52
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• 2014

This study was conducted to analyze if there is a difference between the head hospital and branch hospital by comparing the profitability and operating expenses to patient revenue of oriental medicine hospitals affiliated with universities in order to find whether opening branch hospitals is an appropriate method to increase profitability. Profit indices used for the comparison of head hospital and branch hospital include ratio of operating profit on medical revenue, net-income on medical revenue, net profit to total assets, and operating profit to total assets; and cost indices included ratio of labor costs, material costs and administrative costs. In comparison of profit indices of head hospitals and branch hospitals, head hospitals displayed negative(-) in all four profit index averages while branch hospitals displayed positive(+), showing that branch hospitals have higher profitability. In particular, in the case of head hospitals, ratio of net profit to total assets was -13.6%, while that of branch hospitals was 12.9%, which was higher than 3.1%, the average of Korean oriental medicine hospitals in 2011. As a result of difference analysis between groups of head hospitals and branch hospitals, profit indices of ratio of operating profit on medical revenue, net-income on medical revenue, and ratio of net profit to total assets were found to vary by hospitals, but there was no statistically significant difference between head hospitals and branch hospitals(p<0.1). Only the ratio of operating profit to total assets of head hospitals and branch hospitals indicated significant difference between the two groups, showing that ratio of operating profit to total assets of branch hospitals is larger than that of head hospitals. Meanwhile, the cost indices of ratio of labor costs, material costs and administrative costs in the difference test results did not show significant difference between the head hospital and branch hospital(p<0.1). Thus, it cannot be said that a certain oriental medicine hospital's profitability is high or low depending on whether it is head hospital or a branch as profitability varies depending on the management environment of the hospital. Therefore, oriental medicine hospitals affiliated with universities would need to make efforts to increase their profitability as an individual hospital rather than focusing on whether they are head hospital or a branch.

• 한국기계가공학회지
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• 제7권1호
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• pp.22-31
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• 2008

The operating window method is a novel approach in quality improvement. But it has not received deserved attention in academic research. If a critical factor for competing failure modes can be identified, the probability of failure can be reduced by widening the operating window of this factor. Traditional SN ratio for the operating window advocated by Taguchi has a critical shortcoming, which has been derived under the assumption that failure rates are determined by the operating window factor only. A new metric for robustness is given for the operating window method, which has relaxed the restrictive assumption of Taguchi's SN ratio. And procedures for determining optimal conditions based on the new metric is presented. The effectiveness of the proposed approach over the traditional practice is tested with the aid of a wave soldering process.

• 한국조리학회지
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• 제15권4호
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• pp.212-226
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• 2009

본 연구는 금융감독원 전자공시시스템에 공시된 기업의 재무제표를 활용하여 외식 기업의 재무 비율과 경영 성과의 관계를 파악하고자 하였다. 재무 비율은 재무제표의 두 계정을 조합하여 비율을 계산하여 경영 성과를 제시하는 지표로써, 경영자와 채권자 그리고 투자자는 해당 기업의 재무제표를 평가하기 위한 방법으로 비율 분석을 각기 다른 목적으로 사용하고 있다. 재무 비율과 경영 성과에 대한 분석에 의하면, 상장된 음식료업종 기업은 이자 보상 배율을 제외한 전 부분에서 상관 관계를 보였지만, 외식 기업은 안정성 비율과 성장성비율에 한정해서 상관 관계를 보여주었다. 이와 같은 차이에 근거하여 외식 기업의 경영자는 부채와 자산에 대한 관리와 더불어 비용에 대한 효과적이고 계획적인 관리를 통하여 경영 성과를 개선하여야 할 것이다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.2035-2040
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• 2004

A cone cylinder is used to obtain variable operation conditions for the sonic ejector-diffuser system. The cone cylinder is designed to move upstream and downstream to change the ejector throat area ratio, thus obtaining variable mass flow rates. The present study investigates the effects of ejector throat area ratio and operating pressure ratio on the entrainment of secondary stream for the variable sonic ejector system. In experiment, the ejector throat area is varied in the range from ${\psi}=11.88$ to 66.69, and the operating pressure ratio from $p_{0p}/p_a=1.25$ to 9.0. The results show that the variable sonic ejector system is suitable for a required entrainment ratio of secondary stream by altering the ejector throat area ratio and operating pressure ratio.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.414-417
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• 2004

A cone cylinder is used to obtain variable operation conditions for the sonic ejector-diffuser system. The cone cylinder is designed to be shifted upstream and downstream to change the ejector throat area ratio, thus obtaining variable mass flow rates. The present study investigates the effects of ejector throat area ratio and operating pressure ratio on the entrainment of secondary stream for the variable sonic ejector system. The study is carried out experimentally. The ejector throat area is varied at the range from Ψ= 11.88 to 66.69, and the operating pressure ratio is changed from $P_{op}$ / $P_{a}$=1.25 to 9.0. The results show that the variable sonic ejector system can be operated to obtain specific entrainment ratio of secondary stream by altering the ejector throat area ratio and operating pressure ratio.o.

• The Journal of Asian Finance, Economics and Business
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• 제8권5호
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• pp.109-115
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• 2021

This study aims to examine the effect of Operating Costs and Income, Loan to Deposit Ratio on the Return on Asset (ROA) of Public-Private Foreign Exchange Banks listed on the Indonesia Stock Exchange (IDX) during the 2015-2018 period. This study is a quantitative study using financial reports of Public-Private Foreign Exchange Banks listed on the IDX as a data source. This study's population is 25 Public-Private Foreign Exchange Banks listed on the IDX. This study uses purposive sampling to determine the sample to produce 21 banking companies. Data was analyzed using multiple linear regression methods and descriptive statistics. The F Test calculation results state that all the variables of free operating expenses, operating income, and the loan to deposit ratio simultaneously and significantly affect the return on assets (ROA) variable in Public-Private Foreign Exchange Banks listed on the IDX. This study's results indicate that simultaneously Operational Costs, Operational Income, and Loan to Deposit Ratio have a significant effect on ROA. Operational Costs and Operational Income have a significant negative impact on Return on Assets. The third hypothesis shows that the Loan to Deposit Ratio has a positive and insignificant effect on Return on Assets.