• 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.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.4
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• pp.18-30
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• 2010

As the automobile industry is developing, the number of deaths and injuries has increased. To reduce the damages from automobile accidents, the government of each country proposes experimental conditions for reproducing the accident and establishes the vehicle safety regulations. Automotive manufacturers are trying to make safer vehicles by satisfying the requirements. The Hybrid III crash test dummy is a standard Anthropomorphic Test Device (ATD) used for measuring the occupant's injuries in a frontal impact test. Since a real crash test using a vehicle is fairly expensive, a computer simulation using the Finite Element Method (F.E.M.) is widely used. Therefore, a detailed and robust F.E. dummy model is needed to acquire more accurate occupant injury data and behavior during the crash test. To achieve this goal, a detailed F.E. model of the Hybrid III 5th percentile female dummy is constructed by using the reverse engineering technique in this research. A modeling process is proposed to construct the F.E. model. The proposed modeling process starts from disassembling the physical dummy. Computer Aided Design (CAD) geometry data is constructed by three-dimensional (3-D) scanning of the disassembled physical dummy model. Based on the geometry data, finite elements of each part are generated. After mesh generation, each part is assembled with other parts using the joints and rigid connection elements. The developed F.E. model of dummy is simulated based on the FMVSS 572 validation regulations. The results of simulation are compared with the results of physical tests.

• Journal of Preventive Medicine and Public Health
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• v.30 no.3 s.58
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• pp.530-539
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• 1997

This study was conducted to assess the health risk on the volatile organic compounds such as toluene, xylene, and styrene in painting workplace. It was monitored through personal air sampling during working time in selected 5 workplaces and analysed using gas chromatography. For the settlement of exposure situation, there were regarded working conditions such as working hours, yearly working days, and working years. Also, Monte-Carlo simulation was used for the induction of hazard index using toxicity value from IRIS(Integrated risk information system) database. The results of risk assessment were summarized as follows. 1. The air concentration of toluene was $7.096{\pm}15,644ppm,\;2.586{\pm}4.275ppm\;for\;xylene,\;1.914{\pm}5.320ppm$ for styrene in blast painting workplaces. The level of toluene was different significantly compared with the level of xylene and styrene. 2. Computated chronic daily intake values of 95th percentile on toluene, xylene and styrene treated by Monte-Carlo simulation were 9.616, 3.567, 2.782 mg/kg/day, respectively. 3. Computated hazard index values of 75th percentile on toluene, xylene and styrene treated by Monte-Carlo simulation were 3.5, 1.0 and 1.6, respectively. Adverse health effects on the toluene, xylene and styrene would be expected by working exposure in selected 5 workplaces since the hazard indices of three compounds were exceeded 1 in the surroundings of 75th percentile though having the low emerged frequency.

• Korean Journal of Food Science and Technology
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• v.43 no.6
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• pp.766-772
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• 2011

This study was conducted to evaluate the daily intakes of propyl gallate, EDTA (ethylenediamine tetra acetate), and erythorbic acid for average consumers by age group and the intake of high consumers ($95^{th}$ percentile) in Korea. The average intake of EDTA was $1.14{\mu}g/kg{\cdot}bw/day$, and 0.0% of the ADI (acceptable daily intake) established by JECFA (Joint FAO/WHO Expert Committee on Food Additives). The $95^{th}$ percentile intake of EDTA was $141.24{\mu}g/kg{\cdot}bw/day$ (5.6% of ADI). The average intake of erythorbic acid was $16.93{\mu}g/kg{\cdot}bw/day$, and the 3-6 year-old group had the highest consumption ($58.43{\mu}g/kg{\cdot}bw/day$), which was <1.0% of the ADI established by the EU (European Union). The $95^{th}$ percentile intake of erythorbic acid was $1,320.31{\mu}g/kg{\cdot}bw/day$ and 22.0% of the ADI. In conclusion, daily intakes of propyl gallate, EDTA, and erythorbic acid in Korea were at safe levels in all age groups and also in high consumers.

• Korean Journal of Community Nutrition
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• v.18 no.5
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• pp.525-538
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• 2013

The purpose of this study was to provide information on obesity assessment for Koreans. Among total of 1012 research papers enlisted in the Korean J Community Nutrition form 1996 to 2011, 248 articles were examined in which subjects were divided into more than 2 groups by obesity rate. About the method of anthropometric data collection, more than half of the research papers examined 52.5% and 28.7% of studies utilized the directly measured data and self-described data, respectively. About the utilization of obesity assessment methods, indirect methods of weight-height index (BMI, BMI percentile, and R$\ddot{o}$hrer index) and PIBW (WLR, Broca index, and KDA) were 62.4% and 23.2%, respectably, and the direct method of percent body fat assessment was only 9.3%. The most frequently utilized methods were WLR in under primary and primary school children, and BMI in the middle and high school students and in adults. For primary school students, WLR was the most frequently utilized method up to 2007, but it changed to BMI percentile afterward. Broca Index was no longer utilized since 2008. There were no articles utilizing BMI percentile and R$\ddot{o}$hrer index for obesity assessment in adults. Criteria for obesity assessment were not consistent among research papers: for example, % body fat, 19~40%; BMI, 20~30; BMI percentile, 85th or 95th. In the case of PIBW, 120% of ideal weight was the most frequently utilized criterion for obesity. Based on these findings, we suggest that proper methods and criteria of obesity assessment for each age group should be determined and proclaimed.

• Korean Journal of Community Nutrition
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• v.21 no.1
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• pp.102-111
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• 2016

Objectives: The intention of this study was to find out the impact of mother's body mass index, eating habits, nutrition status and sociodemographic factors on the body mass index of the children. Methods: The study used original data of Korea National Health and Nutrition Examination Survey (2010-2011) and had 957 children in the ages of 1-5 years and 957 mothers of these children, a total 1,914 as subjects. The weights (body mass indexes) of the children, subjects under 5th percentile were classified into a underweight group, 5~84th percentile into a normal weight group, 85-94th percentile into an overweight group and more than 95th percentile into an obesity group based on the 2007 Korean children and adolescents growth chart. Results: We observed that when the body mass index of a mother increased by 1, the possibility that her child would belong to the overweight group increased by 6.5% (95% confidence interval: 1.01~1.13), and the possibility that the child would belong to the obesity group increased by 95% (confidence interval: 1.01~1.18). With regard to the number of deficient nutrients which were ingested according to estimated average requirements (EAR) amid nutrients ingested by the mother increased by 1, the possibility that the child would belong to the obesity group increased by 16.6% (95% confidence interval: 1.01~1.35). In case the birth weight of child increased by 1kg, the odds ratio that the child would belong to the obesity group was 2.022 (95% confidence interval: 1.08~3.77). Conclusions: We conclude that the body mass index, eating habits and nutrition status of the mother had significant effects on the body mass index of the child. Therefore, it is critical to recognize the importance of this observation and provide practical training for eating habits and nutrient intakes in order to achieve healthy growth and prevention of obesity among children.

• Advances in pediatric surgery
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• v.4 no.2
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• pp.125-130
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• 1998

To assess the clinical and nutritional status of long-term survivors of biliary atresia, history taking, medical record review, physical examination (height, weight, MAC, TSF), blood tests (LFT, prothrombin time, platelet count, prealbumin, calcium) and liver needle biopsy were performed in 12 patients in whom Kasai procedure were performed more than 10 years ago at Department of Pediatric Surgery in Seoul National University Hospital. None were below the 5th percentile in height and weight. TSF was above the 75th percentile in all patients and showed good subcutaneous fat deposition. MAC was above the 5th percentile in all patients. Serum prealbumin level was abnormal in 2 patients with abnormal liver function and revealed visceral protein malnutrition. Serum calcium level was decreased below normal range in 4 patients with abnormal liver function. One patient had mild ascites. Five patients had abnormal liver function and 7 patients showed clinical manifestation of portal hypertension. Liver needle biopsy was performed in 5 patients and no cirrhotic change was observed. Although some patients who have survived for more than 10 years after Kasai procedure developed protein malnutrition and vitamin deficiencies, growth and development and nutritional status were generally satisfactory. Five patients(42%) showed normal liver function and no portal hypertension. In conclusion, Kasai procedure is satisfactory as a primary treatment in biliary atresia but significant portion of long-term survivors had abnormal liver function and portal hypertension. Continuous and careful follow-up is necessary to determine when liver transplantation may be indicated.

• Korean Journal of Radiology
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• v.24 no.2
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• pp.133-144
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• 2023

Objective: Cyclin-dependent kinase inhibitor (CDKN)2A/B homozygous deletion is a key molecular marker of isocitrate dehydrogenase (IDH)-mutant astrocytomas in the 2021 World Health Organization. We aimed to investigate whether qualitative and quantitative MRI parameters can predict CDKN2A/B homozygous deletion status in IDH-mutant astrocytomas. Materials and Methods: Preoperative MRI data of 88 patients (mean age ± standard deviation, 42.0 ± 11.9 years; 40 females and 48 males) with IDH-mutant astrocytomas (76 without and 12 with CDKN2A/B homozygous deletion) from two institutions were included. A qualitative imaging assessment was performed. Mean apparent diffusion coefficient (ADC), 5th percentile of ADC, mean normalized cerebral blood volume (nCBV), and 95th percentile of nCBV were assessed via automatic tumor segmentation. Logistic regression was performed to determine the factors associated with CDKN2A/B homozygous deletion in all 88 patients and a subgroup of 47 patients with histological grades 3 and 4. The discrimination performance of the logistic regression models was evaluated using the area under the receiver operating characteristic curve (AUC). Results: In multivariable analysis of all patients, infiltrative pattern (odds ratio [OR] = 4.25, p = 0.034), maximal diameter (OR = 1.07, p = 0.013), and 95th percentile of nCBV (OR = 1.34, p = 0.049) were independent predictors of CDKN2A/B homozygous deletion. The AUC, accuracy, sensitivity, and specificity of the corresponding model were 0.83 (95% confidence interval [CI], 0.72-0.91), 90.4%, 83.3%, and 75.0%, respectively. On multivariable analysis of the subgroup with histological grades 3 and 4, infiltrative pattern (OR = 10.39, p = 0.012) and 95th percentile of nCBV (OR = 1.24, p = 0.047) were independent predictors of CDKN2A/B homozygous deletion, with an AUC accuracy, sensitivity, and specificity of the corresponding model of 0.76 (95% CI, 0.60-0.88), 87.8%, 80.0%, and 58.1%, respectively. Conclusion: The presence of an infiltrative pattern, larger maximal diameter, and higher 95th percentile of the nCBV may be useful MRI biomarkers for CDKN2A/B homozygous deletion in IDH-mutant astrocytomas.

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

• Clinical and Experimental Reproductive Medicine
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• v.45 no.1
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• pp.31-37
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• 2018

Objective: To evaluate the pregnancy rate and time to pregnancy after timed coitus with or without superovulation in infertile young women younger than 35 years old with low serum $anti-M{\ddot{u}}llerian$ hormone (AMH) levels ( < 25th percentile). Methods: A total of 202 patients younger than 35 years old were recruited retrospectively between 2010 and 2012. Ninety-eight women had normal serum AMH levels (25-75th percentile), 75 women had low serum AMH levels (5th ${\leq}$ & < 25th percentile) and 29 women had very low serum AMH levels ( < 5th percentile), according to reference values for their age group. Results: The clinical pregnancy rate was positively associated with AMH levels, but this trend did not reach statistical significance (43.9% vs. 41.3% vs. 27.6% in the normal, low, and very low AMH groups, respectively). The time to pregnancy was longer in the very low AMH group than in the normal AMH group ($13.1{\pm}10.9months$ vs. $6.9{\pm}6.1months$, p= 0.030). The cumulative live birth rate over 18 months was lower in the very low AMH group than in the normal AMH group, with marginal significance (20.0% vs. 55.9%, p= 0.051). The duration of infertility was negatively correlated with achieving pregnancy (odds ratio, 0.953; 95% confidence interval, 0.914-0.994; p= 0.026). Conclusion: Conservative management, such as timed coitus with or without superovulation, should be considered in young patients who have low ovarian reserve without any infertility factors. However, for women with a long duration of infertility or very low serum AMH levels, active infertility treatment should be considered.