• International Journal of Reliability and Applications
• /
• v.5 no.4
• /
• pp.129-145
• /
• 2004

We use a novel, forced censoring technique that closer fits the lower tails of strenth distributions to better estimate extremly smaller percentiles for measuring progress in continuous improvement initiatives. These percentiles are of greater interest for companies, government oversight organizations, and consumers concerned with safely and preventing accidents for many products in general, but specifically for medium density fiberboard (MDF). The international industrial standard for MDF for measuring highest quality is internal bond (IB, also called tensile strengh) and its smaller percentiles are crucial, especially the first percentile and lower ones. We induce censoring at a value just above the median to weight lower observations more. Using this approach, we have better fits in the lower tails of the distribution, where these samller percentiles are impacted most. Finally, bootstrap estimates of the small percentiles are used to demonstrate improved intervals by our forced censoring approach and the fitted model. There was evidence from the study to suggest that MDF has potentially different failure modes for early failures. Overall, our approach is parsimonious and is suitable for real time manufacturing settings. The approach works for either strengths distributions or lifetime distributions.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
• /
• v.13 no.3
• /
• pp.9-15
• /
• 2017

In this study, set values of PICV(Pressure Independent Control Valve) were simulated according to the pressure distribution and velocity. The higher the set value and the open rate, as the lower the pressure in the neck. On the contrary, the lower the set value and open rate, as the higher the pressure in the neck. When the set value was small, the pressure was distributed sufficiently and confirmed that the pressure was generated by the VOF, confirming that it could generate a vapor pressure. When the set value 100 %, the lower corn open rate of the differential pressure was 46 % to 29 %, set value 100 % was 29 % to 19 %, and set value 6 % was 12 % to 6 % for the lower corn open rate percentile, it was limited to within 50 %. Thus, the results of this study on the correlation between open rate and differential pressure of the set value of the PICV will be beneficial to improve performance of flow control valves and contribute to their efficient operation used for a hydronic system.

• Journal of the East Asian Society of Dietary Life
• /
• v.14 no.1
• /
• pp.20-26
• /
• 2004

The purpose of this study was to investigate dietary taurine intakes, plasma taurine levels and urinary taurine excretions of women in Seoul(Kangbuk-ku) and Kyunggi(Yeoju) area, Korea. Seventy married women aged 39.7$\pm$8.9 have volunteered for this study: 36 from Seoul area and 34 from Kyunggi area. Diet samples were collected from the participants and the samples included three meals (breakfast, lunch and supper), snacks, drinks and whatever the participants had eaten for 24 hours. The plasma was obtained by allowing a 5 $m\ell$ fasting blood sample to be in a heparinized tube for 30 min and centrifuging it at 11,000${\times}$g for 20 min. The collected diets were blended, centrifuged and deproteinized. Taurine levels in the diet and plasma were determined as the dabsyl derivative using HPLC with Rf-detector. The intake of taurine ranged from 6.8 to 837.8 mg/day and its mean value was l45.5$\pm$164.0 mg/day (mean$\pm$SD). The 90th, 50th and 10th percentile values of the taurine intake were 280.0, 94.3 and 26.8 mg/day, respectively. There was a significant difference between two groups: 202.0$\pm$204.9 for Seoul area and 85.5$\pm$67.2 mg/day for Kyunggi area(p<0.00l). The taurine level in plasma ranged from 42.1 to 201.9 $\mu$mol/L and its mean value was 74.9$\pm$22.8 $\mu$mol/L. The 90th, 50th and 10th percentile values of the plasma taurine were 101.1, 70.7 and 54.6 $\mu$mol/L, respectively. There was no significant difference between Seoul area and Kyunggi area in plasma taurine level.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.18 no.6
• /
• pp.624-631
• /
• 2008

This study evaluates the impact of aircraft noise on people's health using the Todai health index(THI). A questionnaire survey was conducted in the vicinity of Gimpo International Airport in Seoul, South Korea, from August 8th to September 9th, 2005. The survey area was divided into three groups based on different aircraft noise levels : area (1) for $80{\sim}85$ WECPNL, area (2) for $75{\sim}80$ WECPNL and area (3) for less than 75 WECPNL. In each area, approximately 200 respondents were sampled. Twelve scale scores of THI are converted to dichotomous variables based on scale scores of 90 percentile value or 10 percentile value in the control group. Logistic regression analysis taking twelve scores converted as the dependent variables and WECPNL(area), age, gender as the independent variables is conducted. Significant dose-response relationships are found in the scale of MOUT, DEPR, NERV, LIFE. Factor analysis was carried out and 2 factors are extracted. Those two factors might be called the "somatic factor" and the "mental factor". The dose-response relationship between two factors and noise seems to be unclear. Unexpectedly the odds ratio of the menatl factor in area (2), where the noise exposure level is lower than that of the area (1), is the highest and the annoyance in this area is also higher than area (1).

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.12
• /
• pp.5037-5041
• /
• 2015

Background: An hCG regression curve has been used to predict the natural history and response to chemotherapy in gestational trophoblastic disease. We constructed hCG regression curves in high-risk gestational trophoblastic neoplasia (GTN) treated with EMA/CO and identified an optimal hCG level to detect EMA/CO resistance in GTN. Materials and Methods: Eighty-one women with GTN treated with EMA/CO were classified as primary high-risk GTN (n = 65) and single agent-resistance GTN (n = 16). The hCG levels prior to each course of chemotherapy were plotted in the 10th, 50th, and 90th percentiles to construct the hCG regression curves. Diagnostic performance was evaluated for an optimal cut-off value. Results: The median hCG levels were 264,482 mIU/mL mIU/mL and 495.5 mIU/mL mIU/mL for primary high-risk GTN and single agent-resistance GTN, respectively. The 50th percentile of the hCG level in primary high-risk GTN and single agent-resistance turned to normal before the 4th and the 2nd course of chemotherapy, respectively. The 90th percentile of the hCG level in primary high-risk GTN and single agent-resistance turned to normal before the 9th and the 2nd course of chemotherapy, respectively. The hCG level of ${\geq}118.6mIU/mL$ mIU/mL at the 5thcourse of EMA/CO predicted the EMA/CO resistance in primary high-risk GTN patients with a sensitivity of 85.7% and a specificity of 100%. Conclusion: EMA/CO resistance in primary high-risk GTN can be predicted by using an hCG regression curve in combination with the cut-off value of 118.6 mIU/mL at the 5thcourse of chemotherapy.

• Environmental Analysis Health and Toxicology
• /
• v.26
• /
• pp.9.1-9.9
• /
• 2011

Objectives: In order to evaluate which temperature index is the best predictor for the health impact assessment of heat stress in Korea, several indexes were compared. Methods: We adopted temperature, perceived temperature (PT), and apparent temperature (AT), as a heat stress index, and changes in the risk of death for Seoul and Daegu were estimated with $^1{\circ}C$ increases in those temperature indexes using generalized additive model (GAM) adjusted for the non-temperature related factors: time trends, seasonality, and air pollution. The estimated excess mortality and Akaike's Information Criterion (AIC) due to the increased temperature indexes for the $75^{th}$ percentile in the summers from 2001 to 2008 were compared and analyzed to define the best predictor. Results: For Seoul, all-cause mortality presented the highest percent increase (2.99% [95% CI, 2.43 to 3.54%]) in maximum temperature while AIC showed the lowest value when the all-cause daily death counts were fitted with the maximum PT for the $75^{th}$ percentile of summer. For Daegu, all-cause mortality presented the greatest percent increase (3.52% [95% CI, 2.23 to 4.80%]) in minimum temperature and AIC showed the lowest value in maximum temperature. No lag effect was found in the association between temperature and mortality for Seoul, whereas for Daegu one-day lag effect was noted. Conclusions: There was no one temperature measure that was superior to the others in summer. To adopt an appropriate temperature index, regional meteorological characteristics and the disease status of population should be considered.

• Korean Journal of Veterinary Research
• /
• v.49 no.2
• /
• pp.149-155
• /
• 2009

The objective of this study was to analyze data from the planned national serological monitoring program for Aujeszky's disease (AD) using a simulation model to evaluate probable outcomes expected in the sample derived from the simulated herds at predefined within-herd prevalence and herd prevalence. Additionally, prevalence at animal- and herd-level estimated by the stochastic simulation model based on the distributions of the proportion of infected herds and test-positive animals was compared with those of data from a national serological survey in 2006, in which 106,762 fattening pigs from 5,325 herds were tested for AD using a commercial ELISA kit. A fixed value of 95% was used for test sensitivity, and the specificity was modeled with a minimum, most likely and maximum of 95, 97 and 99%, respectively. The within-herd prevalence and herd prevalence was modeled using Pert and Triang distributions, respectively with a minimum, most likely and maximum point values. In all calculations, population size of 1,000 was used due to lack of representative information. The mean number of infected herds and true test-positives was estimated to be 27 herds (median = 25; 95% percentile 44) and 214 pigs (median = 196; 95% percentile 423), respectively. When testing 20 pigs (mean of 2006 survey) in each herd, there was a 3.3% probability that the potential for false-positive reactions due to less than 100% specificity of the ELISA test would be detected. It was found that the model showed prevalence of 0.21% (99% percentile 0.50%) and 0.5% (99% percentile 0.99%) at animal- and herd-level, respectively. These rates were much similar to data from the 2006 survey (0.62% versus 0.83%). The overall mean herd-level sensitivity of the 2006 survey for fattening pigs was 99.9%, with only a 0.2% probability of failing to detect at least one infected herd.

• Journal of Food Hygiene and Safety
• /
• v.25 no.2
• /
• pp.148-152
• /
• 2010

Domestic studies for identification of causality between children exposure to toxic chemicals, such as arsenic (As) and resulted hazardous effects were not implemented. This study was conducted to probabilistically estimate dietary As intake and health risk assessment for young children and all age-specific populations from the consumption of As-contaminated rice of Korea. Arsenic intakes for young children (1 to 6 years old) from As-contaminated rice were higher than other age-specific groups, based on a dose-per-body weight basis. Based on the current EPA cancer slope factor for As, estimated cancer risks (to the skin cancer) associated with dietary intake of As-contaminated rice for 1 to 2 years old group and 3 to years old group are 1.76 per 10,000 and 3.16 per 10,000, respectively, at the 50th percentile. Based on possible reference levels (0.005 mg/kg/day) for children, mean and $95^{th}$ percentile value of HQ from rice for young children are very below 1.0, which is a regulatory limit of non-carcinogenic risks for human.

• Journal of Food Hygiene and Safety
• /
• v.17 no.3
• /
• pp.137-145
• /
• 2002

Tributyltin compounds have been increasingly used in the form of plastic stabilizers, catalytic agents, industrial agricultural biocides, antifouling paint, and pesticides. Among these organotin compounds, large amounts of tributyltin(TBT) and triphenyltin(TPT) have been used as antifouling agents because they have a superior ability to prevent marine organism from being encrusted on ship bottoms and in culturing nets. Environmental pollution by these organotin compounds in the aquatic environment were undertaken. The international maritime Organization's established a provisional tolerable daily intake(TDI) of 1.6[micro]g TBTO/kg/ B.W. The Food and Agiculture Organization (of the United Nations)/world Health Organization's (FAO/WHO) proposed a TDI of 0.5ug TPT/kg BW/d. This study is conducted monitoring of TBT on seafoods in Korea and risk assessment for exposure on TBT in seafoods. Total hazard index(using Reference Dose : 0.3 ug TBTO/kg B.W/day) of intake exposure on seafoods is 0.04 as the 50th percentile, 0.08 as the 95th percentile. This value is estimated by Monte-Carlo simulation using Crystal Ball(Decisioneering Co., 2001).

• Journal of Families and Better Life
• /
• v.7 no.1
• /
• pp.59-78
• /
• 1989

The purpose of this study is to clarify the value orientation about family life between the older generations and college student. For this purpose, questionnaire were distributed to the older generations and college students in Seoul. Among them 920 data were obtained To obtain the family value scale, item analysis through pearson's correlation and factor analysis were used in pretest, frequency distribution, percentile, mean , t-test , and step-wise multiple were used for data analysis. The results are summarized as follows. 1) Male college students show traditional tendency and female college students show modern tendency especially sex-role attitude, ancestor worship attitude, patriarchy attitude. 2) Male and female of the older generations how traditional tendency. 3) The older generations show traditional tendency, college students show modern tendency, especially sex-role attitude and kinship attitude. 4) Male adults and male college students show traditional tendency. 5) Female adults show traditional tendency , female college students show modern tendency. In female, generation gap is more serious than males. 6) the most influencial socio-demographic variables on family value consciousness of the older generations are the religion and education, In case of college students, sex, major, religion, family income grown-up area effect on their value consciousness about family life, Based on the above findings , we should develop school education and many social programs to reduce the generation gap.