• Journal of Nutrition and Health
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• v.38 no.7
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• pp.578-585
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• 2005

Maternal zinc deficiency is relatively common worldwide, but its consequences for pregnancy outcome are not established. The purpose of this study was to examine the effect of zinc status in the second trimester on pregnancy outcome. Subjects were 248 pregnant Korean women (25-28 wk gestation). Cord blood was collected from subgroup of 69 women and pregnancy outcome data were obtained from 185 babies. Anthropometry measurement, dietary intake, and biochemical characteristics of pregnancy and cord serum substances were measured. The subjects were divided into quartiles on the basis of maternal serum Zn concentration; $ZnQ_1$ (< 25 percentile), $ZnQ_2$ ($26\~50$ percentile), $ZnQ_3$ ($51\~75$ percentile), and $ZnQ_4$ ($76\~100$ percentile). Zn groups were compared in terms of various maternal factors, concentrations of cord serum substances, and pregnancy outcome. Maternal serum Zn concentration was $118.4\;{\pm}\;35.5\;{\mu}g/dl$ as mean. Intake of Zn was lower than Korean RDA. The rate of Zn deficiency among all subjects was $8.5\%$. Maternal serum Zn levels belonged to normal range. Cord serum Zn level was about $154.7\%$ of maternal serum level. Intakes of energy, calcium, iron, folic acid, and riboflavin did not meet the Korean RDA for pregnant women by gestational age. The mean birth weight of neonates is 3083 $\pm$ 697 g, of whom $9.1\%$ were of low birth weight (< 2,500 g). Maternal serum Zn level was positively correlated with pre-pregnancy weight, pre-pregnancy body mass index, and vitamin C intake (p < 0.05). $ZnQ_1$ group had significantly lower maternal serum iron concentration and higher cord serum cholesterol than those in other groups. Maternal serum Zn level, cord serum Zn level, and dietary Zn intake were no related to the pregnancy outcome. The birth weight had a correlation with the maternal hemoglobin and albumin concentration. In conclusion, at this study, we could not find the association with maternal Zn status in 2nd trimester and pregnancy outcome.

• The Journal of Pediatrics of Korean Medicine
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• v.36 no.3
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• pp.49-62
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• 2022

Objectives This study aimed to provide evidence for the use of Korean medicine in underweight patients by analyzing the medical records of underweight children and adolescents. Methods Children and adolescents who visited Korean pediatrics at Kyung Hee University Hospital from June 1, 2019 to May 31, 2022, who had an age-specific weight percentile which was less than 5 and diagnosed with E639.005 or R628.001 were selected for the study. A retrospective chart review was conducted by examining the medical records of subjects who received Korean medical treatment. The treatment effect was analyzed in all subjects and subgroups by comparing changes in height, weight, and body mass index (BMI) percentiles before and after Korean medicine treatment. Results A total of 55 underweight subjects were included in the study. General characteristics such as distribution by sex, age, number of visits, and weight percentile, and clinical characteristics such as diagnosis, past history, family history, drug history, current or past symptoms, and symptom differentiation were collected. The composition of herbal medicines and the contents of other Korean medical treatments were analyzed. In the case of treatment effect, the weight and BMI percentile of all subjects increased significantly. Conclusions This study was conducted to suggest Korean medicine as a method of proper weight management in children and adolescents. In the future, follow-up studies with a large number of subjects and controlled variables, such as the period of taking herbal medicine, are needed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2D
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• pp.105-111
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• 2010

Operating speed is one of key elements in the design and operation of freeway. Few studies have been carried out macroscopically to find characteristics of free-flow speed (FFS) using small sample size and not considering the conditions of traffic volume and the effects of hour periods. As an attempt to find out the characteristics of FFS, this study microscopically analysed both the distributions of freeway FFS and percentile speeds according to traffic volume and daily hour periods using huge sample size. It was found out that speed distributions are changed and showed different behaviors under the conditions of traffic volumes(1-5 veh/30sec) and daily hour periods(0-5, 6-8, 9-11, 12-19, 20-23). V85(85th percentile speed) at morning, night, and midnight period decreases according to increase in traffic volume respectively, whereas V85 at day time does not show considerable differences. So the behaviors of V85 according to hour periods dramatically changed according to the increase in traffic volume.

• Journal of the Korean Society of Food Culture
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• v.25 no.2
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• pp.170-178
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• 2010

We conducted this study to determine the factors associated with childhood obesity. The subjects were 170 preschool children in Busan. Data were collected by using questionnaires which asked for information about socioeconomic status, parental perception of their child's weight status and dietary/physical activity behavior. BMI was calculated for each child and their classification was determined, according to their age and sex, as follows: "overweight" at or above the 85th percentile, "normal" for the 15th-85th percentile, and with a BMI below the 15th percentile the children were deemed as underweight. Classification according to BMI percentile showed that 23.5% ($18.25{\pm}1.33\;kg/m^2$) of the children were overweight, 62.9% ($15.51{\pm}0.76\;kg/m^2$) normal, and 13.5% ($13.23{\pm}2.86\;kg/m^2$) were underweight. Socioeconomic status, as represented by the parents' level of education, the occupation of the father and the household income, did not affect the results. However, mothers working outside the household was a factor that was more likely to affect the weight status (p<0.05). Among mothers whose children were overweight, 30% underestimated their children's weight status (believing them to be of normal weight when they were overweight), and 25% failed to recognize the necessity of weight control for their overweight children. While sedentary activity and total daily activity levels were not related to BMI, the level of physically active leisure activity was inversely correlated with BMI (p<0.05). Although there were no differences in total energy intake, dietary behavior was significantly related to weight status. Overweight children had poor eating tendancies: they eat faster (in less than 15 minutes), overeat, and eat late at night. Based on our findings where hereby recommended the following interventions to help limit weight problems in Korean pre-schoolers: early promotion of active leisure behavior and healthy eating habits, along with attempting to correct parental misperception of healthy weight status for children.

• The Korean Journal of Applied Statistics
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• v.37 no.2
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• pp.177-189
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• 2024

The run length is defined as the number of samples or subgroups taken before the control chart statistic exceeds the control limits. Because the distribution of run length is typically asymmetric and has a large variability, it may not be appropriate to use ARL (average run length) alone to design control charts and evaluate performance. In this paper, we introduce the concept of percentile (PL)-based design of control charts, and propose the procedure for PL-based design of EWMA (exponentially weighted moving average) charts. For the PL-based design of EWMA, we present a fitted function for the control chart coefficient, given specific percentile parameters. Additionally, we perform simulations to compare the proposed design with the ARL-based design. The simulation results show that the proposed design yields improvements in monitoring in-control processes while maintaining the ability to detect out-of-control performance.

• Environmental and Resource Economics Review
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• v.13 no.1
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• pp.49-82
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• 2004

The study aimed to evaluate cancer damage cost due to risk from benzene inhalation. We performed health risk assessment based on US EPA guideline to estimate annual population risk in Ulsan metropolitan city. Also, we estimated a willingness-to-pay amount for reducing a cancer mortality rate to evaluate a value of statistical life. We combined the annual population risk and the value of statistical life to calculate the cancer damage cost. In the health risk assessment, we applied the benzene unit risk ($2.2{\times}10^{-6}{\sim}7.8{\times}10^{-6}$) in the US EPA'S Integrated Risk Information System to assess the annual population risk. Average concentration of benzene in ambient air is $7.88{\mu}g/m^3$(min: 1.16~max: $23.32{\mu}g/m^3$). We targeted an exposure population of 516,641 persons who aged over 30 years old. Using a Monte-Carlo simulation for uncertainty analysis, we evaluated that the population risk of benzene during ten years in Ulsan city is 2.90 persons (5 percentile: 0.32~95 percentile: 9.11persons). And the monthly average WTP for 5/1,000 cancer mortality reduction during ten years is 14,852 Won(95% C.I: 13,135~16,794 Won) and the implied VSL is 36 million Won(95% C.I: 30~40 million Won). Cancer damage cost due to risk from benzene inhalation during 10 years in Ulsan city is about 104 million Won(5 percentile: 13~95 percentile: 328 million Won). Health benefit cost to reduce a cancer mortality risk of benzene is about 50 million Won is Ulsan metropolitann city. But, it is very important that this cost is not for all health damage cost of cancer mortality in some area. We just recommended a model for evaluating a cancer risk reduction, so we must re-evaluate an integrated application of total VOCs damage cost including benzene.

• Journal of Korea Water Resources Association
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• v.56 no.2
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• pp.115-124
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• 2023

Currently, as the frequency of extreme weather events increases, the scale of damage increases when extreme weather events occur. This has been providing forecast information by investing a lot of time and resources to predict rainfall from the past. However, this information is difficult for non-experts to understand, and it does not include information on how much damage occurs when extreme weather events occur. Therefore, in this study, a risk matrix based on heavy rain damage rating was presented by using the impact forecasting standard through the creation of a risk matrix presented for the first time in the UK. First, through correlation analysis between rainfall data and damage data, variables necessary for risk matrix creation are selected, and PERCENTILE (25%, 75%, 90%, 95%) and JNBC (Jenks Natural Breaks Classification) techniques suggested in previous studies are used. Therefore, a rating standard according to rainfall and damage was calculated, and two rating standards were synthesized to present one standard. As a result of the analysis, in the case of the number of households affected by the disaster, PERCENTILE showed the highest distribution than JNBC in the Yeongsan River and Seomjin River basins where the most damage occurred, and similar results were shown in the Chungcheong-do area. Looking at the results of rainfall grading, JNBC's grade was higher than PERCENTILE's, and the highest grade was shown especially in Jeolla-do and Chungcheong-do. In addition, when comparing with the current status of heavy rain warnings in the affected area, it can be confirmed that JNBC is similar. In the risk matrix results, it was confirmed that JNBC replicated better than PERCENTILE in Sejong, Daejeon, Chungnam, Chungbuk, Gwangju, Jeonnam, and Jeonbuk regions, which suffered the most damage.

• IE interfaces
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• v.17 no.1
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• pp.1-12
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• 2004

In a modern semiconductor device manufacturing industry, statistical bin limits on wafer level test bin data are used for minimizing value added to defective product as well as protecting end customers from potential quality and reliability excursion. Most wafer level test bin data show skewed distributions. By Monte Carlo simulation, this paper evaluates methods and sample size effect regarding determination of statistical bin limits. In the simulation, it is assumed that wafer level test bin data follow the Poisson distribution. Hence, typical shapes of the data distribution can be specified in terms of the distribution's parameter. This study examines three different methods; 1) percentile based methodology; 2) data transformation; and 3) Poisson model fitting. The mean square error is adopted as a performance measure for each simulation scenario. Then, a case study is presented. Results show that the percentile and transformation based methods give more stable statistical bin limits associated with the real dataset. However, with highly skewed distributions, the transformation based method should be used with caution in determining statistical bin limits. When the data are well fitted to a certain probability distribution, the model fitting approach can be used in the determination. As for the sample size effect, the mean square error seems to reduce exponentially according to the sample size.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.3
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• pp.300-309
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• 2008

Variations in PM10 concentration between 2000 and 2005 from 84 urban air monitoring stations operated by the government were analyzed. The K-means cluster analysis was attempted using annual average and the 99th percentile of daily averages as parameters. The results obtained by excluding Asian dust episode days were compared with those obtained by using all available data. In any cases, the cluster with the highest mean concentration was mostly composed of stations in Seoul and Gyeonggi. Annual average of the cluster with the highest mean concentration showed a distinct decreasing trend, but that excluding Asian dust episode days did not show such a trend. Without Asian dust episode days high concentrations of monthly averages in March and April were also not observed. The effect of Asian dust was more pronounced in the 99th percentile of daily averages. The 99th percentile of daily averages of the cluster with the highest mean concentration was the highest in June following downs in April and May.

• Journal of Korean Society on Water Environment
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• v.24 no.6
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• pp.676-681
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• 2008

The evaluation of the effluent water quality of sewage treatment plant is one of the most important factor in calculating total maximum daily loads (TMDLs). Current method to calculate 95% upper limit of effluent water quality of sewage treatment plant assuming normal distribution of data needs to be implemented in case of non-normal distribution. We have investigated the applicability of percentile ranking method as a non-parametric statistical analysis in case of non-normal distribution of data.