• Communications for Statistical Applications and Methods
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• v.14 no.2
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• pp.443-457
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• 2007

This paper deals with the problem of testing the existence of change in mean and estimating the change-point using nonparametric bootstrap technique. A test statistic using Gombay and Horvath (1990)'s functional form is applied to derive a test statistic and nonparametric change-point estimator with bootstrapping idea. Achieved significance level of the test is calculated for the proposed test to show the evidence against the null hypothesis. MSE and percentiles of the bootstrap change-point estimators are given to show the distribution of the proposed estimator in simulation.

• Communications for Statistical Applications and Methods
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• v.6 no.2
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• pp.467-478
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• 1999

This paper deals with the problem of change-point estimation where there is one level change in location with iid errors. A change-point estimator using rank average is proposed with the proof of its consistency. A comparison study of various change-point estimators is done by simulation on the mean the proportion and the variance when the errors are from the normal and the double exponential distributions.

• Journal of Nutrition and Health
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• v.28 no.8
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• pp.759-770
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• 1995

This study was conducted to investigate the effect of weight control by use of commercial formula diet and nutrition education on 36 obese women over a period of 6 months. During the study it motivated ways for women to control their weight and improve their health, thus analyzing variables that influence weight control. To help weight control, for the first 3 weeks, along with 1 regular mea, 2-3 liquid formula diets of 135㎉ per pack a day were provided within the 1,200-800㎉ range. For 6 months since then, all 3 meals were taken regularly and it was recommended that energy which is 500㎉ less than energy requirement be taken. To evaluate the effect of weight change by the weight control program, anthropometric measurements, biochemicl parameter, and food behavior are measured. The mean body mass index(BMI) was 30.1$\pm$3.8(25.0-43.6) and it was in the upper 5 percentile of the mean BMI of Korean women. The percent of body fat was significantly reduced from 29.1$\pm$2.4 to 26.4$\pm$2.3, showing that the weight control program induced not only a change in weight but also a change in body composition. The body circumference such as waist and hip circumference and skinfold thickness measurements of biceps, triceps, subscapular and surprailiac were reduced significantly, but the mean waist-to-hip ratio didn't change. Singnificantly improved food behavior score measured by the questionnaire indicated that the weight-contorl program induced the change of the food behavior, as well. Weight loss also induced biochemical parameters of the subject, thus total cholesterol, LDL-Cholesterol, and triglycerol which were in the high range of the normal values were reduced to 20.2%(p<0.01), 22.2%(p<0.01), 25.8%(p<0.01), repectively. HDL-cholesterol didn't change significantly, but the ratio of HDL to total cholesterol increased(p<0.01).

• Journal of the Korean Geographical Society
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• v.48 no.1
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• pp.19-36
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• 2013

This study aimed to investigate the change of humidity by city size in South Korea. Using daily mean relative humidity and water vapor pressure during the period of 1954~2011 for 14 weather stations in South Korea, the change of humidity by city size was analyzed. The change of relative humidity had a continuous decreasing trend for the period of 1954~2011. The decreasing trend in large city was bigger than these of rural one. The seasonal relative humidity was significantly changed in spring and winter. The change of water vapor pressure was rarely changed significance of the results by city size. It was not shown the result to constant trend by city size. There was a negative correlation between relative humidity and mean temperature. And change of relative humidity was correlated with city size. Moreover, there was not correlation between relative humidity and water vapor pressure by city size. The decreasing trend of relative humidity was similar to increasing trend of temperature by urbanization. However, there was not shown significant result of water vapor pressure.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.8 no.1
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• pp.69-80
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• 2001

This study was done to investigate the relation of smoking temptation, stage of change in smoking cessation, nicotine dependency and perceived health status in middle aged men. Convenience samples of 176 subjects who were either smoked or used to smoke, aged between 30 to 64, living in Seoul and Kyungi province area in Korea were selected for the study. The data was collected from December 1, 1999 to June 30, 2000. The research instrument were Stage of Change of Smoking Cessation Measure (DiClemente et al. 1991). Smoking Temptation Measure (Velicer, DiClemente, Rossi, Prochaska. 1990), Perceived Health Status Measure (McDowell & Newell, 1996), and Nicotine Dependency Scale (FTQ: Fagerstrom, 1978). The data were analyzed using the SAS Program. The result of the study are as follows : 1. The analysis of variance and multiple comparison showed that according to the stage of change, there were significant mean differences in the three sub-factors of smoking temptation; 'positive affect situation (F=12.64, p=.0001)', 'negative affect situation (F=16.01, p=.0001)', 'habitual craving situation (F=14.43, p=.0001)' and nicotine dependency (F=4.12, p=.0033) The mean score for smoking temptation for the subjects who were in the precontemplation stage outweighed the mean score for smoking temptation for subjects who were in the maintenance stage. 2. Through discriminant analysis, it was found that negative affect situation was the most influential variable of the smoking temptation sub-factors which can be used to discriminate stage of change. 3. The analysis of Pearson correlation coefficients showed that there was a significant positive relation between nicotine dependency and negative affect situation of smoking cessation((r=0.2182, p=0.0045) and a significant negative relation between nicotine dependency and perceived health status(r=-0.2115, p=0.0059).

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.6
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• pp.9-18
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• 2017

The objective of this study was to estimate the climate change impact on inflow to Namgang Dam using SWAT (Soil and Water Assessment Tool) model. The SWAT model was calibrated and validated using observed flow data from 2003 to 2014 for the study watershed. The $R^2$ (Determination Coefficient), RMSE (Root Mean Square Error), NSE (Nash-Sutcliffe efficiency coefficient), and RMAE (Relative Mean Absolute Error) were used to evaluate the model performance. Calibration results showed that the annual mean inflow were within ${\pm}5%$ error compared to the observed. $R^2$ were ranged 0.61~0.87, RMSE were 1.37~7.00 mm/day, NSE were 0.47~0.83, and RMAE were 0.25~0.73 mm/day for daily runoff, respectively. Climate change scenarios were obtained from the HadGEM3-RA. The quantile mapping method was adopted to correct bias that is inherent in the climate change scenarios. Based on the climate change scenarios, calibrated SWAT model simulates the future inflow and evapotranspiration for the study watershed. The expected future inflow to Namgang dam using RCP 4.5 is increasing by 4.8 % and RCP 8.5 is increasing by 19.0 %, respectively. The expected future evapotranspiration for Namgang dam watershed using RCP 4.5 is decreasing by 6.7 % and RCP 8.5 is decreasing by 0.7 %, respectively.

• The Journal of Korean Obstetrics and Gynecology
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• v.25 no.1
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• pp.11-19
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• 2012

Purpose: The purpose of this study is to evaluate the synergic efficacy of oriental herb medicine for osteoporosis patients by examining whether there is any change in BMD. Osteoporosis patients are classified into a group having taken Fosamax and the other group having taken Fasamax and Samgieumgamibang in this study. Methods: Mean BMD and T-score are measured in all patients before and 3 months after treatment. Results: 1. The group having taken Fosamax showed no statistically significant mean BMD change before and after treatment. 2. The group having taken Fosamax showed no statistically significant T-score change before and after treatment. 3. The group having taken both Fosamax and Samgieumgamibang showed increase in mean BMD, which does not bear statistically significant change. 4. The group having taken both Fosamax and Samgieumgamibang showed statistically significant T-score change before and after treatment(p<0.05). Conclusions: After treatment, BMD in patients having taken Fosamx did not change significantly, but in patients having taken both Fosamax and Samgieumgamibang increased, which proves the efficacy of oriental herb medicine for osteoporosis patients.

• Journal of Climate Change Research
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• v.6 no.4
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• pp.277-281
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• 2015

A Chinese cabbage is one of important vegetables which accounts for more than 60 percent of leaf vegetable. However, cultivation area and yield of Chinese cabbage are steadily decreasing recently. Because meteorological changes destabilize the balance of Chinese cabbage, we need to study on meteorological factors affecting estimation of Chinese cabbage yield. So we conducted a panel analysis using mean temperature, maximum temperature, minimum temperature, precipitation and sunshine's duration from August to November for estimation of Chinese cabbage yield. As the results, we found that if the mean temperature of September increase by $1^{\circ}C$ the amount of production of Chinese cabbage per unit area was increased by 348.6 kg/10a. We also found that the mean temperature of October increased by 174.8 kg/10a, that of November 148 kg/10a, the difference between the maxium temperature and the minimum temperature of October equals 443.3 kg/10a. However, we found that the difference between the maximum temperature and the minimum temperature of November decreased 274.1 kg/10a.

• Journal of Korean Society for Quality Management
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• v.23 no.3
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• pp.93-101
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• 1995

We present a brief survey concerning the relations between mean residual life and failure rate. Change points of mean residual life and failure rate are known to be different in general and we explore such situations in this paper. A few parametric models which show bathtub-shaped failure rate are examined in details, including the shape of its corresponding mean residual life function. We give some graphical comparisons of trend changes of mean residual life and failure rate for various choices of parameters for each parametric model.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.4
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• pp.566-572
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• 2015

Objectives: The major objective of this study was to analyze insomnia after the change to consecutive day shift from day and night shift in a motor assembly factory. Materials: Data were collected at before and after shift system change through a survey conducted by a labor union. We analyzed transition of PSQI(Pittsburgh Sleep Quality Index) among 222 workers by separating the day shift week and night shift week. The cut-off point of insomnia was 8.5 on the PSQI. Results: Mean PSQI in the day shift week significantly did not decrease, going from $6.36{\pm}3.23$ to $6.46{\pm}3.00$(p=0.612 by paired t-test), Mean PSQI for night shift week significantly decreased from $8.31{\pm}3.36$ to $6.19{\pm}3.18$(p<0.001 by paired t-test). However, mean PSQI in the day shift week increased from $6.33{\pm}3.83$ to $7.11{\pm}2.86$ in ${\geq}50$ years(p=0.085, by repeated measured ANOVA). Mean PSQI score in the night shift week improved more in the married group(from $8.38{\pm}3.27$ to $6.12{\pm}3.18$) than in the non-married group(from $7.82{\pm}3.27$ to $6.12{\pm}3.18$)(p=0.038, by repeated measured ANOVA). Conclusions: The change to consecutive day shift improved insomnia in night shift. However, insomnia in the day shift week was worsened among those more than 50 years old.