• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.464-464
• /
• 2010

A few years ago, for maintaining high stability and production yield of production equipment in a semiconductor fab, on-line monitoring of wafers is required, so that semiconductor manufacturers are investigating a software based process controlling scheme known as virtual metrology (VM). As semiconductor technology develops, the cost of fabrication tool/facility has reached its budget limit, and reducing metrology cost can obviously help to keep semiconductor manufacturing cost. By virtue of prediction, VM enables wafer-level control (or even down to site level), reduces within-lot variability, and increases process capability, $C_{pk}$. In this research, we have practiced VM on $SiO_2$ etch rate with optical emission spectroscopy(OES) data acquired in-situ while the process parameters are simultaneously correlated. To build process model of $SiO_2$ via, we first performed a series of etch runs according to the statistically designed experiment, called design of experiments (DOE). OES data are automatically logged with etch rate, and some OES spectra that correlated with $SiO_2$ etch rate is selected. Once the feature of OES data is selected, the preprocessed OES spectra is then used for in-situ sensor based VM modeling. ICP-RIE using 葰.56MHz, manufactured by Plasmart, Ltd. is employed in this experiment, and single fiber-optic attached for in-situ OES data acquisition. Before applying statistical feature selection, empirical feature selection of OES data is initially performed in order not to fall in a statistical misleading, which causes from random noise or large variation of insignificantly correlated responses with process itself. The accuracy of the proposed VM is still need to be developed in order to successfully replace the existing metrology, but it is no doubt that VM can support engineering decision of "go or not go" in the consecutive processing step.

• Korean Journal of Community Nutrition
• /
• v.3 no.3
• /
• pp.368-379
• /
• 1998

The purpose of this study was to assess the energy value of breakfast and its relation to total daily nutrient intake and serum lipid. Dietary intakes were evaluated through the 3-day dietary recalls(interview for 1day and self-report for 2 days) from 333 Korean urban adults aged 20-49 year. Serum lipids in fasting blood samples were measured form 98 of those 333 adults. Low energy breakfast(<15% of daily energy intake) was consumed by 22.6% of males and 18.5% of females. 59.4 of males and 43.3% of females consumed a breakfast of average energy intake(15-25% daily energy intake) ; and 18.1 of males and 38.2% of females consumed a significant contribution to a total daily nutrient intake. The daily nutrient intake except crude fiber and vitamin A, B, B, and C in males and except vitamin C in females significantly increased as the energy value of breakfast increased. The differences in energy and nutrient intakes at breakfast were not made up for by other meals. To make matters worse, the satisfactory-energy breakfast group took more energy at dinner compared with the low-energy and average-energy breakfast group took more energy at dinner compared with the low-energy and average-energy breakfast groups in females. Among serum lipid parameters, TG was negatively correlated with energy provided at breakfast, and total cholesterol and LDL-cholesterol had a negative correlation with energy and carbohydrates provided at breakfast in males. For females TG was positively correlated with the ratio of carbohydrates to energy at breakfast but negatively correlated with the ratio of fat to energy at breakfast. These results suggest that satisfactory energy intakes at breakfast have positive effects on the adequacy of daily nutrient intake and may positively affect the serum lipid status.

• Journal of Korean Neurosurgical Society
• /
• v.37 no.5
• /
• pp.336-339
• /
• 2005

Objective: The goal of this study is to establish the anatomical criteria of the normal and stenotic lumbosacral extraforaminal tunnel, and also to determine the effect of the pathologic intervertebral disc on the size of extraforaminal tunnel in the lumbosacral spine. Methods: MRI and CT scans were reviewed and classified into two groups: (1) 40 patients with normal discs at L5- S1 (Group 1) and (2) 43 patients that had undergone successful decompression surgery for extraforaminal entrapment at the lumbosacral region(Group 2). In these two groups, the following parameters were compared are compared: the distance between the disc margin and the ala (lumbosacral tunnel) on the axial MRI, and the posterior disc height at L5-S1 on the mid-sagittal MRI. Results: In the group 1, the mean distance of the lumbosacral tunnel on the axial MRI was $10.1{\pm}2.2mm$. The mean posterior disc height at L5-S1 was $7.4{\pm}1.7mm$ on the mid-sagittal MRI. In the group 2, the mean distance between the disc margin and the ala (costal process) was $1.6{\pm}1.3mm$ on the axial MRI. The average posterior disc height was $4.4{\pm}1.5mm$ on the mid-sagittal MRI. The posterior disc height and the size of the lumbosacral tunnel between the two groups were statistically different on the paired t-test (p<0.0001). However, the posterior disc height was not positively correlated with the size of the extraforaminal tunnel for group 2 (p=0.909). Conclusion: The extraforaminal stenosis was correlated to pathologic disc. However, the posterior disc height was not correlated to the size of the of the extraforaminal tunnel.

• Nutrition Research and Practice
• /
• v.10 no.1
• /
• pp.74-80
• /
• 2016

BACKGROUND/OBJECTIVES: Cardiovascular diseases is a major cause of death and is responsible for 23.8% of deaths in Korea. Clinical symptoms manifest in adulthood, but susceptibility begins in utero. Elevated homocysteine levels and adiposity might be linked to a greater risk in children as well as adults. We hypothesized that those who have simultaneous risk for folate and adiposity would be affected with elevated homocysteine levels at 3 years of age. SUBJECTS/METHODS: From the ongoing birth cohort at Ewha Womans University Mok-Dong Hospital, we compared adiposity parameters, serum homocysteine, and folate levels in 238 children (118 boys and 120 girls) at three years of age. The relationship between birth outcome, current weight and body mass index (BMI), postnatal growth, and homocysteine level were assessed using correlation and general linear model. Additionally, we assessed the combined effect between blood folate status and adiposity on current homocysteine levels. RESULTS: Birth characteristics were not correlated with homocysteine. Current weight, BMI, upper-arm circumference, skinfold thickness, waist circumference, and hip circumference were positively correlated with homocysteine at three years of age (P < 0.05). Folate level was negatively correlated with homocysteine at three years of age (P < 0.0001). A relative high anthropometric measure which is compatible with adiposity and low folate level was associated with high homocysteine levels. CONCLUSION: We found a combined effect of adiposity and folate levels with homocysteine levels at three years of age. This implicates the beneficial role of folate supplementation in the high-risk population at an early age.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.32 no.1
• /
• pp.55-63
• /
• 2019

In engineering problems, many random variables have correlation, and the correlation of input random variables has a great influence on reliability analysis results of the mechanical systems. However, correlated variables are often treated as independent variables or modeled by specific parametric joint distributions due to difficulty in modeling joint distributions. Especially, when there are insufficient correlated data, it becomes more difficult to correctly model the joint distribution. In this study, multivariate kernel density estimation with bounded data is proposed to estimate various types of joint distributions with highly nonlinearity. Since it combines given data with bounded data, which are generated from confidence intervals of uniform distribution parameters for given data, it is less sensitive to data quality and number of data. Thus, it yields conservative statistical modeling and reliability analysis results, and its performance is verified through statistical simulation and engineering examples.

• Journal of Cancer Prevention
• /
• v.23 no.4
• /
• pp.191-196
• /
• 2018

Background: Type 2 diabetes mellitus (T2DM) and cancer are serious health problems worldwide, and their prevalences have been on the rise in recent years. It has been reported that adropin plays an important role in the development of T2DM, oxidative stress, inflammation, and obesity. However, there is limited information available on T2DM from human studies, especially for the Korean population. In this study, we aimed to investigate the correlation between adropin levels and obesity of Korean T2DM patients. Methods: Thirty-six T2DM patients were recruited for this study. The participants were further classified into female (n = 12) and male (n = 24). Their body composition, metabolic parameters, inflammatory factors, and oxidative stress were measured. Results: The severity of obesity is more manifested in male than in female. Plasma triglyceride (TG) and high-sensitivity C-reactive protein (hs-CRP) levels of male were significantly higher than female. The plasma adropin and adiponectin level of female was significantly higher than male. The body weight, body mass index (BMI), body fat mass were negatively correlated with the plasma adropin level in female, whereas adropin has positive correlation with adiponectin in female. The hs-CRP was negatively correlated with the plasma adropin level in female and male. malondialdehyde, reactive oxidative species, and $TNF-{\alpha}$ was not significantly correlated with adropin in patients with T2DM. Conclusions: These findings suggest that adropin may be more used as a biomarker for predicting the risk of obesity and inflammation in Korean patients with T2DM, especially women.

• Journal of The Korean Society of Emergency Medicine
• /
• v.29 no.6
• /
• pp.603-615
• /
• 2018

Objective: We analyzed the association between regional weather and temporal changes on the daily occurrence of trauma emergencies and their severity. Methods: In this cross-sectional prospective study, we investigated daily atmospheric patterns in trauma episodes in 1,344 patients in Cheongju city, South Korea, from January 2016 to December 2016 and analyzed the association of trauma occurrence and Injury Severity Scores (ISS) with weather conditions on a daily scale. Results: The mean age of trauma patients was $53.0{\pm}23.8years$ and average ISS was $9.0{\pm}2.0$. Incidence of trauma was positively correlated with average temperature (r=0.512, P<0.001) and atmospheric pressure (r=0.332, P=0.010) and negatively correlated with air pollutants (particulate matter less than $2.5{\mu}m^3$ [PM2.5], r=-0.629, P<0.001; particulate matter less than $10{\mu}m^3$ [PM10], r=-0.679, P<0.001). ISS was not significantly correlated with climate parameters and air pollutants, and variability was observed in the frequency and severity of trauma by time of day (highest occurrence, 16-20 pm; highest ISS, 4-8 am), day of the week (highest occurrence and highest ISS, Saturday), month of the year (highest occurrence, July; highest ISS, November), and season (highest incidence, summer; highest ISS, autumn). Conclusion: The study shows a positive relationship between trauma occurrence and specific weather conditions, such as atmospheric temperature and pressure. There was a negative relationship between concentrations of PM2.5 or PM10, and trauma occurrence. However, no correlation was observed between weather conditions or the concentrations of air pollutants and ISS. In addition, seasonal, circaseptan, and circadian variations exist in trauma occurrence and severity. Thus, we suggest that evaluation of a larger, population-based data set is needed to further investigate and confirm these relationships.

• The Korean Journal of Pain
• /
• v.35 no.1
• /
• pp.78-85
• /
• 2022

Background: The current pandemic has affected people's health multidimensionally. This study aims to investigate musculoskeletal pain, sleep quality, depression levels, and their relationships in individuals belonging to different age groups during COVID-19 in Turkey. Methods: A web-based self-administered survey that consisted of demographic questions, The Beck Depression Inventory (BDI), Pittsburgh Sleep Quality Index (PSQI), and scores of musculoskeletal pain was sent to participants. Pearson correlation analysis was used for determining the statistical relationship between variables. Results: The study includes 1,778 participants. The highest percentage for mild, moderate, and severe pain was in the head (49.8%), back (15.5%), and head (11.5%), respectively. The PSQI-total had shown a weak correlation with pain levels in all body parts. The highest correlation for sleep quality and pain levels was between the PSQI-5 and lower back pain. There was a weak correlation between PSQI-2 and the BDI score, and a moderate correlation between the PSQI-1, PSQI-5, PSQI-7, PSQI-total, and BDI score. Pain in all body parts showed a weak correlation with depression level. Conclusions: This study showed that musculoskeletal pain was varied in body parts with different intensities according to age groups in Turkey during the pandemic. The most common pain was in the head, back, and lower back. Headache was found correlated with the parameters of sleep quality. Pain of the head, neck, back, lower back, and shoulder were correlated with sleep latency. Sleep quality was associated with depression and musculoskeletal pain, while musculoskeletal pain was correlated with depression.

• Imaging Science in Dentistry
• /
• v.51 no.4
• /
• pp.439-446
• /
• 2021

Purpose: The aim of this study was to identify correlations between the STOP-Bang score and upper airway dimensions using cone-beam computed tomography (CBCT) scans. Materials and Methods: This study included 101 subjects (46 men, 55 women) from dental patients who received CBCT scans from 2014 to 2020. The patients were divided into those with a low obstructive sleep apnoea (OSA) risk (STOP-Bang score<3) and those with an intermediate to high OSA risk (STOP-Bang score≥3), and their upper airway dimensions were then analysed on CBCT scans. Comparisons between the low-risk and intermediate/high-risk groups were conducted using the t-test and the Mann-Whitney test. Correlations between the total STOP-Bang score and upper airway dimension parameters were established using Spearman correlation coefficients. P values≤0.05 were considered to indicate statistical significance. Results: Intermediate/high-risk subjects were predominantly male and over 50 years of age, with a higher body mass index. They had significantly longer upper airways, smaller average airway volumes, and smaller widths and antero-posterior dimensions of the narrowest upper airway segment. The total upper airway length was positively correlated with the STOP-Bang score (r_s=0.278). The average volume (r_s= -0.203) and width of the narrowest upper airway segment(r_s= -0.305) were both negatively correlated with STOP-Bang scores. Conclusion: Subjects with higher STOP-Bang scores had upper airways that were longer, narrower, and smaller in terms of average volume. CBCT scans taken for dental patients as part of investigative procedures could be correlated with STOP-Bang scores to screen for patients at risk of OSA.

• Journal of The Korean Society of Integrative Medicine
• /
• v.11 no.4
• /
• pp.259-268
• /
• 2023

Purpose : This descriptive research study aimed to investigate the relationship among academic self-efficacy, sleep quality, and quality of life(QoL) and to identify the factors that affect quality of life(QoL) in nursing students during the COVID-19 pandemic. Method : A total of 214 nursing students from three South Korean colleges were included in the study. Collected data were analyzed using the SPSS/WIN 21.0 program. Independent t-test and one-way analysis of variance were used to analyze the differences in academic self-efficacy, sleep quality, and quality of life(QoL) according to general characteristics. In addition, post-hoc Scheffè test and Pearson's correlation coefficient were used to examine the relationship among the three parameters. Stepwise multiple regression analysis was conducted to identify influential factors on the nursing students' quality of life(QoL). Results : The average academic self-efficacy, sleep quality, and quality of life(QoL) scores were 3.15±0.27, 32.28±7.54, and 81.12±13.11, respectively. Quality of life(QoL) positively correlated with academic self-efficacy but negatively correlated with sleep quality. Academic self-efficacy negatively correlated with sleep quality. Sleep quality, satisfaction with major, sex, average income, and academic self-efficacy influenced quality of life(QoL), whose explanatory power was 34.9 %. Conclusion : Sleep quality was the most influential factor of quality of life(QoL). However, further studies to validate our findings and studies focusing on developing intervention programs to improve nursing students' sleep quality and quality of life(QoL) are warranted.