• Journal of Radiation Protection and Research
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• 제31권4호
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• pp.197-201
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• 2006

Daily and seasonal variations of the ambient gamma ray exposure rates were measured by using a pressurized ion chamber from January 2003 to December 2005 in the CheongJu Regional Radiation Monitoring Post and the patterns of the distributions were studied. The annual average of the daily variation of the exposure rate was $\sim0.17{\mu}R/h$. The exposure rate was found to be maximum during 8:00 am to 9:00 am and minimum during 8:00 pm to 10:00 pm. For the annual data, the exposure rate was the minimum during the month of February. The exposure rate increased from February to mid-October (except during the period from May to July with no change) and decreased from October to February. The seasonal variation was found to be about $1{\mu}R/h$. Most of the measured values (96%) of the exposure rates fell under the normal distribution with a deviation of less than 4.8% and the remaining 4% had large fluctuations caused mainly by the rainfalls.

• 한국의류학회지
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• 제23권3호
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• pp.483-494
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• 1999

This study investigated the relation between seasonal variation of clothing weight and its resting metabolic rate to determine the relation between proper living temperature and cold/heat tolerance. Thirty six subjects(18 males and females twenties) were composed to obtain the clothing weight(Total clothing weight) and resting metabolic rate for a year and grouped four seasons : spring (Mar-May) Summer(Jun-Aug) Fall(Sep-Nov) and Winter(Dec-Feb). The data of males and females were respectively divided into three groups by cluster analysis with clothing weight. 1. The resting metabolic rate of male(41.1kcal/m2/hr) was higher than that of female(33.2kcal/m2/hr). It is suggested there is gender difference in the resting metabolic rate(p<.001) 2. The resting metabolic rate of male and female was the highest in Winter. It is suggested there is seasonal variation in the resting metabolic rate(p<.001) 3. It was found that there was relation between clothing weight and resting metabolic rate. The difference of resting metabolic rate between Summer and Winter which is profitable to adaptation to living temperature was significant in light clothing weight in male as well as in female. 4. In comfortable sensation most subjects responded that he/she felt 'comfortable' except Winter. However the heavy clothing weight group felt 'a little uncomfortable' throughout all seasons. l In thermal sensation most subjects responded that he/she felt 'neutral' And then the heavy clothing weight group responded warmer in summer and cooler in winter than light clothing weight group. From the results it was confirmed that male and female showed seasonal variations in clothing weight and resting metabolic rate. Also the resting metabolic rate of male and female was influenced by the clothing weight. In short seasonal variation of resting metabolic rate was larger in light clothing weight group than in heavy clothing weight group. Therefore light clothing weight group is advantgeous in living temperature to improve cold/heat tolerance and it also shows that living with the light clothing weight may enhance the degree of adaptation to change of living environment

• 보건행정학회지
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• 제1권1호
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• pp.27-41
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• 1991

The purpose of this study is to estimate cesarean section rate in Korea and analyze characteristics of health care institution which affect regional variation in the rate. We have searched vaginal and cesarean section deliveries among Diagnosis Related Group dat based upon insurance claim bills which have been submitted to Korean Insurance Corporation for two years since March, 1985. The results are as follows: 1. Out of all delivery cases of 87,500, cesarean section rate was 16.3% (14,299 cases). 2. Cesarean section rate varied according to size and ownership of health care institutions. In above 6- bed sized hospitals, the rate was at about 20% higher than small sized institutions, but rather in hospitals that have more than 500 beds, it was somewhat low. Classified by the hospital ownership, the rate was low at 18.4% in hospitals of religious organization and highest at private or corporate hospitals. 3. This study shows large regional variation in cesarean section rate; there are two times differences between region with the highest and lowest rate. Strongly related factors in that variation was the ownership of health care institution and urbanization variables. Low level of cesarean section rate in a region is explained by high proportion of delivery cases at institutions of religious organization and at insitutions in county level site. This result shows that apart from medical conditions of patients, indications of cesarean section differs from health care providers, and especially ownership of institution strongly affect them. Cesarean section rate in Korea is supposed to be at high level and development of utilization review programs to keep appropriate cesarean section rate is needed.

• 한국자동차공학회논문집
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• 제4권3호
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• pp.92-101
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• 1996

In a gasoline engine, the characteristics of air flow is very important not only for the design of the intake system geometry bout also for the accurate measurement of the induction air mass. In this study, an air flow rate measurement of the induction air mass. In this study, an air flow rate measurement was conducted by using the hot wire flow meter at the upstream of the intake port and the throttle. At the upstream of the throttle, the overshoot phenomena of the air flow rate by fast throttle opening were analyzed with choked flow. At the upstream of the intake port, the cylinder variation of the air flow rate and the difference between fast throttle opening and closing were showed during the unsteady state by the throttle step change. The results of this study can be used for the design of the throttle valve geometry and cylinder by cylinder control.

• 보건행정학회지
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• 제22권3호
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• pp.427-450
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• 2012

Objectives : This study examined the factors influencing variation by local areas of antibiotics prescription rate in upper respiratory infections (URI) according to the public reporting. Methods : We used the National Health Insurance Claims Data which the clinics claimed for URI (Korean Standard Classification of Disease, J00 ~ J06) in ambulatory care. The period of analysis was from the first quarter (from January to March) of 2005 to the first quarter of 2007. The number of samples was total 242 local areas that included all clinics (N = 7,942), which prescribed antibiotics for URI in ambulatory care. Results : None of the demographic and socioeconomic characteristic indicators was statistically significant. Among the provider factors, An increase in number of doctors and the average annual antibiotics prescription rate (from 2003 to 2004) for URI by local area were significantly related to an increase of antibiotics prescription rate according to the public reporting. And an increase in number of pediatric clinics, the proportion of clinics less than 5 years since has opened and the average annual fluctuation of antibiotics prescription rate (from 2003 to 2005) were significantly related to a decrease in antibiotics prescription rate by local area according to the disclosure of information. Conclusions : According to the public reporting, the antibiotics prescription rate in clinics had decreased sharply. However, the reduction of antibiotic prescription rate varied in different local areas. The factors influencing variation by local areas in antibiotics prescription rate can be used for establishing effective strategies to reduce variation by region in antibiotics prescription rate.

• 신재생에너지
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• 제7권4호
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• pp.30-36
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• 2011

The objective of this study is to investigate the effects of the refrigerant charge amount on the performance of a water-to-water ground source heat pump with a variation of compressor speed and the secondary fluid flow rate. The water-to-water ground source heat pump was tested by varying refrigerant charge amount from -40% to 20% of full charge. Compressor speed was changed from 30 Hz to 75 Hz and the secondary fluid flow rate was adjusted from 6 LPM to 14 LPM. For all test conditions, EWTs of an indoor heat exchanger and an outdoor heat exchanger were maintained at standard conditions of ISO 13256-2. The slope of the COP with the variation of charge amount is much steeper at undercharged conditions than that at overcharged conditions. For all compressor speed, the variation of the system performance according to charge amounts showed the similar trends. However, the optimum charge amount of the system increased a little with an increment of compressor speed. When the secondary fluid flow rate decreased, the system was optimized at higher refrigerant charge amount conditions.

• 한국유체기계학회 논문집
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• 제13권6호
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• pp.51-56
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• 2010

A numerical simulation is carried out to investigate the effect of flow rate variation and performance characteristics of double-suction centrifugal pump. Two types of pump which have different impeller inlet breadth and curvature of the shroud line consist of six blades impeller and shroud ring. Finite-volume method with structured mesh and $k-\omega$ Shear Stress Transport turbulence model was used to guaranty more accurate prediction of turbulent flow in the pump impeller. Total head, power and overall efficiency were calculated to obtain performance characteristics of two types of pump according to the variation of flow rate. From the results, impeller having smooth curve along the shroud line obtained good performance. The lower flow rate, the more circulation region, flow unsteadiness and complicate flow pattern are observed. Complicated internal flow phenomena through impellers such as flow separation, pressure loss, flow unsteadiness and performance are investigated and discussed.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.143.1-143.1
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• 2011

The objective of this study is to investigate the effects of the refrigerant charge amount on the performance of a water-to-water ground source heat pump with a variation of compressor speed and the secondary fluid flow rate. The water-to-water ground source heat pump was tested by varying refrigerant charge amount from -40% to 20% of full charge. Compressor speed was changed from 30 Hz to 75 Hz, and the secondary fluid flow rate was adjusted from 6 LPM to 14 LPM. For all test conditions, EWT of an indoor heat exchanger and an outdoor heat exchanger were maintained at standard conditions of ISO 13256-2. The slope of the COP with the variation of charge amount is much steeper at undercharged conditions than that at overcharged conditions. For all compressor speed, the variation of the system performance according to charge amounts showed the similar trends. However, the optimum charge amount of the system increased a little with an increment of compressor speed. When the secondary fluid flow rate decreased, the system optimized at higher refrigerant charge amount conditions.

• 한국환경과학회지
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• 제23권9호
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• pp.1601-1608
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• 2014

Plasma reactor was used for the inactivation of Phytophthora capsici which is phytophthora blight pathogen in aquiculture. Effects of first voltage, second voltage, air flow rate, pH, incubation water concentration were examined. At the low $1^{st}$ voltage, under 80 V, the lag phase was noticed within 30 sec, however, it was not shown over 100 V. The variation of optimum operation condition was not shown by the variation of microorganisms. However, the inactivation rate was different by the variation of species of microorganisms. The inactivation rate and efficiency were increased by the increase of $2^{nd}$ voltage. The highest initial inactivation rate was shown at pH 3 and the rate was decreased by the increase of pH. The inactivation rate increased by the increase of air flow rate, however, it was shown as similar at the rate of 4 L/min and 5 L/min. The inactivation rate was distinctly decreased at the three times concentration of incubation solution comparing at the distilled water and basic incubation solution.

• 보건행정학회지
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• 제14권2호
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• pp.138-162
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• 2004

This study was performed to investigate small area variation in rates of three common surgeries in general surgery department across 156 small areas. Three surgery rates were analyzed; Anal and/or stomal procedures, inguinal and/or femoral hernia procedures, appendectomy. Methods: We used health insurance claims data and the number of patients were 13,845, 2,154 and 7,151 persons respectively. Surgery rates were directly standardized with age and sex and logistic regression was used to analyze surgery rates. Results: Mapping of the surgery rates, there was small area variation in anal and/or stomal procedures. The clinic which was located in more competitive market and chose DRG payment system tends to do more anal and/or stomal procedures. There was no factor except DRG bed rates had effect on rate of inguinal and/or femoral hernia procedures. Conclusions: Findings of this study will contribute to developing investigation method on small area variation and policy to reduce the variation such as developing evidence based medical practice guideline.