• 한국의료질향상학회지
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• 제3권2호
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• pp.70-85
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• 1997

Background : 6.1% of red blood cells and whole blood issued to the operating room was not transfused to the patients and discarded in Seoul National University Hospital in 1994. Objectives : We planned to set up an effective management program of blood in the operating room and we investigated whether this program could reduce the disposal rate of blood. Methods : We made a guideline of blood management in the operating room through a workshop. The guideline was revised after a preliminary application. The revised guideline was applied for 5 months from May to September in 1996. The disposal rate was compared before and after the installation of the new program. Results : 5,336 units of blood were issued to the operating room for 5 months. Disposal rate of red blood cells and whole blood was markedly reduced from 6.2% in May to 2.1% in September(p<0.05). The average disposal rate was 3.7% during the five months. Conclusion : We were able to reduce the disposal of unused blood in the operating room through the development and the application of a new blood management program.

• 한국농공학회지
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• 제16권4호
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• pp.3600-3610
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• 1974

Experimental work of batch-type dryer was conducted to develop its optimurm operating conditions by analyzing the major factors which affect the drying performance. A laboratory batch-type dryer was constructed and tested for various levels of heated-air rates, and depths of grain deposit. Tong-il rice variety having the initial moisture content of approximaely 23 per cent in wet basis was used for the experiment. The criteria selected for establishing the optimum operating condition were the drying performance rate, the thermal efficiency, and the operational cost of the dryer. The results of the study are summarized as follows: 1. The performance rate of dryer for a specific operating condition was defined as total amount of material dried per hour when the moisture content of grains in the upperlayer reaches to 16 per cent in wet basis. The optimum operating conditions as viewed in the rate of drying performance could be justified by functional realtionship between the depth of grain deposit and air flow rate. In other words, there was a definite depth of grain deposit for a given air-rate which make the dryer performance maximum. The optimum grain depth for the batch-type dryer with 3.3㎡ loading area and with the attached axial fan was about 35cm. 2. The thermal efficiency for the dryer was evaluated by the ratio of the latent heat required to evaporate the grain moisture to the heat input required to raise the ambient air-temperature to 40 degree centigrade. The optimum operating condition as viewed in term of thermal efficiency analyzed was that grater depth and lower air flow-rate may be desirable. This condition is contracted with the optimum condition as viewed by the dryer performance rate. 3. The annual operating cost of batch-type dryer was analyzed for different annual hour of use and for different operation condition. The optimum condition as viewed in terms of operating cost was almost identical to one as viewed in terms of dryer performance rate. Therefore, the most economical use of batch-type dryer for the same annual operating hours can be obtained when the dryer operated in the condition of maximum dryer performance rate. Increasing the annual operating hour may be desirable to cut down the dryer operation cost, since the annual hour of dryer use is much sensitive to the operating cost than any peractical conditions of dryer operation. 4. The most desirable operational condition as justified by combining all the criteria, dryer performance rate, thermal efficiency and annual operating cost, could be concluded to operate the dryer in the condition of maximum performance rate. The condition in general is identical to the lowest operation cost for a given annual operating hour.

• 한국신뢰성학회지:신뢰성응용연구
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• 제11권4호
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• pp.433-445
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• 2011

Duty cycle is determined as the ratio of operating time to total time. Duty cycle in reliability prediction is one of the significant factors to be considered. In duty cycle application, non-operating time failure rate has been easily ignored even though the failure rate in non-operating period has not been proved to be small enough. Ignorance of non-operating time failure rate can result in over-estimated system reliability calculation. Furthermore, utilization of duty cycle in reliability prediction has not been evaluated in its effectiveness. In order to address these problems, two reliability models, such as MIL-HDBK-217F and RIAC-HDBK-217Plus, were used to analyze non-operating time failure rate. This research has proved that applying duty cycle in 217F model is not reasonable by the quantitative comparison and analysis.

• 산학경영연구
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• 제19권1호
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• pp.25-34
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• 2006

직접시공이나 하도급시공은 건설산업기본법에 의해 정한 시행령에 따라 시공하는 것이 원칙이나 직접시공이나 하도급시공시 수익성을 비교하여 이익 창출을 극대화하는 방향으로 의사결정이 된다. 이 연구에서는 민간공사 사례를 바탕으로 직접시공과 하도급시공의 공사원가와 수익성을 비교분석하였다. 자료 수집은 S건설에서 2002년과 2003년에 공사한 근린생활 및 단독주택을 토대로 하였다. 공사건수의 사례는 직접시공과 하도급시공 각각 3건의 공사에 의한 평균비율 값에 의하여 비교분석하였다. 이 연구의 사례를 분석한 결과, 공급가액 대비 매출총이익에 대한 수익률은 하도급시공이 직접시공 보다 1.3% 높은 수익률을 올린 것으로 분석되었다. 영업이익에 대한 수익률은 하도급시공이 직접시공보다 2.3% 높은 수익률을 올린 것으로 분석되었다. 마지막으로 하도급시공(영업이익률 11.7%)이 직접시공 공사에 대해 4대 보험료 차감후의 최종 영업 이익률이 4.4% 더 많이 발생한 것으로 분석되었다. 그러므로 건설회사는 하도급을 주는 것이 수익률이 높다는 것을 알 수 있고, 노무자 관리 또한 용이한 것으로 나타났다.

• 한국병원경영학회지
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• 제4권1호
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• pp.41-65
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• 1999

This study was attempted to identify the factors affecting profitability of general hospital in Kyung-In Region. Operating profit to gross revenues and net profit to gross revenues were used as a proxy indicator for profitability of hospitals. The unit of analysis was hospital, and the data were collected 5 years data from 20 hospitals. The major findings are as follows; (1) The average operating profit rate was 1.03% and the net profit rate was -5.00% in twenty hospitals in the Kyung-In Region for the last five years. In terms of maximum surplus, the operating profit rate was 14% and net profit rate was 3.40%. In terms of maximum loss revenue, the operating profit rate was -16.56% and the net profit rate was -22.83%. (2) Since the year 1993, which was the starting year of this study, the operating profits and the net profits consistently decreased. (3) Analyzing the difference in profits among various hospital groups, the tertiary hospital group and the 501-1000 beds group exhibited the highest in operating profit rate. Also, among the higher grade number of beds in hospital group, per 100 beds group, the 41-50 beds group exhibited the highest in operating profit rate. There is a statistically significant difference in those groups(p<0.05, p<0.01). (4) In the health care delivery system, the profit gain in the secondary hospital was 51.5% and in the tertiary hospital was 72.4%. Based on the number of beds in each hospital group, the highest profit gain was 75.0% in the over 1001 beds group, and 71.4% in the 501-1000 beds group. Also, among the higher grade number of beds in hospital group, per 100 beds group, the 41-50 beds group exhibited 88.6% surplus. (5) According to the surplus difference based on the analysis of health care utilization, a group with over 31 patients in bed turnover rate, a group with over 96% in bed occupancy rate and group with over 9% in emergency cases to outpatient visits exhibited the highest profit gains. In addition, a group with over 301 patients in daily outpatient visits per 100 beds and group with 11-12 days average length of stay exhibited the highest profit gains. These results are statistically significant(p<0.05, p<0.01). (6) According to a stepwise regression analysis, the variables measuring the bed turnover rate, number of licensed beds, and number of outpatient visits per specialist explain 34.1% of the variation in operating profits. In terms of net profits, the new outpatient visits, the bed turnover rates and the number of general bed variables explain 30.6%. These results are statistically significant(p<0.01).

• 한국병원경영학회지
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• 제15권4호
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• pp.43-62
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• 2010

This study provides an evidence on the determinants of the profitability of university hospital by analyzing university hospital-level data set of hospital performance during the year 2007 (32 university hospitals in total). For the study, a multiple regression model is employed in which profitability index obtained from the DEA computations, operating margin to total asset and gross revenue are used as the dependent variables, and a number of hospital operating characteristics are chosen as the independent variables such as ownership type, location, bed size, period of establishment, bed occupancy rate, admission ratio of outpatients, patients per medical specialist, personnel cost per patient, liabilities to total assets, current ratio, fixed ratio, total asset turnover, medical assistance rate and public indicator. First, the results indicate that the bed occupancy rate and liabilities to total assets are positively and significantly associated with operating margin to total asset. Second, number of beds, the bed occupancy rate and number of patients per medical specialist are positively and significantly associated with operating margin to gross revenue. Third, the bed occupancy rate, number of patients per medical specialist, liabilities to total assets, total asset turnover are positively and significantly associated with profitability index revealed from DEA.

• Korean Chemical Engineering Research
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• 제53권4호
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• pp.440-444
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• 2015

Effects of operating variables on the solid circulation rate were investigated in a three-phase circulating fluidized bed, of which inside diameter was 0.102m and height was 3.5m, respectively. Gas velocity, primary and secondary liquid velocities, particle size and height of solid particles piled up in the solid recycle device were chosen as operating variables. The solid circulation rate increased with increasing primary and secondary liquid velocities and height of solid particles piled up in the solid recycle device, but decreased with increasing particle size. The value of solid circulation rate decreased only slightly with increasing gas velocity in the riser. The values of solid circulation rate were well correlated in terms of dimensionless groups within the experimental conditions.

• 한국물환경학회지
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• 제27권1호
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• pp.54-60
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• 2011

To evaluate the feasibility of electrodialysis for copper removal from industrial wastewater, the effect of operating parameters on the removal of copper was experimentally estimated. The limiting current density (LCD) linearly increased with the copper concentration and the flow rate. The time when the copper concentration of diluate reaches to 3 mg/L was linearly proportional to initial concentration of diluate, and the concentration of concentrate did not affect the removal rate. Increase in the flow rate gave a positive effect on the removal rate and became insignificant at flow rates greater than 2.4 L/min. The removal rate increased with the applied voltage. From the operation of the electrodialysis module used in this research, the flow rate of 2.4 L/min and the voltage corresponding to the 80~90% of LCD were found be the optimum operating condition for the copper removal from highly concentrated copper solutions.

• 한국연소학회:학술대회논문집
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• 한국연소학회 1999년도 제19회 KOSCO SYMPOSIUM 논문집
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• pp.129-138
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• 1999

In this paper, our main issue is that establishing the control procedure of continuous gas flow rate according to combustion fan RPM. For this, first, we decide the optimum operating condition of gas swirl burner through analysis of combustion characteristics - thermal efficiency, combustion efficiency and exhaust gases such as CO, $CO_{2}$, $O_{2}$, $NO_{x}$ and THC. Second, fuel gas flow rate of gas valve is decided with considering excess air ratio and combustion fan RPM is decided by the target of combustion air flow rate. Finally, experimental operating equation is acquired by regression for gas valve and combustion fan. This equation is the control equation of continuous gas flow rate and always gas flow rate is decided by combustion fan operating RPM.

• 제어로봇시스템학회논문지
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• 제3권3호
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• pp.311-317
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• 1997

DTG(dynamically tuned gyroscope) is a sensor detecting disturbance in angle velocity control loop of EOTS(electro optical tracking system), which is used for the stabilization of gimbal. DTG is classified into rate mode or rate integrated mode according to operating mode. In this paper, basic principles and characteristics of DTG, depending on to operating mode, are compared and the model of rate integrated mode DTG is proposed. Also, the validity of the presented model is verified by computer simulations and experiments.