• Journal of the Korean Association of Geographic Information Studies
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• v.7 no.2
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• pp.37-46
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• 2004

In order to decrease the area damaged by forest fires and to prevent the occurrence of forest fires, we are making an effort to improve prevention measures for forest fires. The objective of this study is to classify hazard regions where forest fires occur based on the factors that contribute to the occurrence of forest fires. Forest fire sites in the Uiseong-gun, Gyeongsangbuk-do were surveyed according to the factors of forest type and topographic characteristics where the forest fires occurred. We used a correlation analysis to determine the forest fire occurrence factors and a conditional probability analysis and GIS to determine a forest fire danger index. The resulting forest fire danger index was used in the classification of forest fire occurrence risk regions.

• Safety and Health at Work
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• v.9 no.1
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• pp.95-100
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• 2018

Background: Respiratory protection equipment (RPE) is the last resort to control exposure to workplace air pollutants. A comprehensive respiratory protection program (RPP) ensures that RPE is selected, used, and cared properly. Therefore, RPP must be well integrated into the occupational health and safety requirements. In this study, we evaluated the implementation of RPP in Iranian petrochemical industries to identify the required solutions to improve the current status of respiratory protection. Methods: This cross-sectional study was conducted among 24 petrochemical industries in Iran. The survey instrument was a checklist extracted from the Occupational Safety and Health Administration respiratory protection standard. An index, Respiratory Protection Program Index (RPPI), was developed and weighted by analytic hierarchy process to determine the compliance rate (CR) of provided respiratory protection measures with the RPP standard. Data analysis was performed using Excel 2010. Results: The most important element of RPP, according to experts, was respiratory hazard evaluation. The average value of RPPI in the petrochemical plants was $49{\pm}15%$. The highest and lowest of CR among RPP elements were RPE selection and medical evaluation, respectively. Conclusion: None of studied petrochemical industries implemented RPP completely. This can lead to employees' overexposure to hazardous workplace air contaminants. Increasing awareness of employees and employers through training is suggested by this study to improve such conditions.

• Geomechanics and Engineering
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• v.13 no.5
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• pp.861-879
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• 2017

Coal and gas outburst is a serious dynamic disaster that occurs during coal mining and threatens the lives of coal miners. Currently, coal and gas outburst is commonly predicted using single indicator and its critical value. However, single indicator is unable to fully reflect all of the factors impacting outburst risk and has poor prediction accuracy. Therefore, a more accurate prediction method is necessary. In this work, we first analyzed on-site impacting factors and precursors of coal and gas outburst; then, we constructed a Fisher discriminant analysis (FDA) index system using the gas adsorption index of drilling cutting ${\Delta}h_2$, the drilling cutting weight S, the initial velocity of gas emission from borehole q, the thickness of soft coal h, and the maximum ratio of post-blasting gas emission peak to pre-blasting gas emission $B_{max}$; finally, we studied an FDA-based multiple indicators discriminant model of coal and gas outburst, and applied the discriminant model to predict coal and gas outburst. The results showed that the discriminant model has 100% prediction accuracy, even when some conventional indexes are lower than the warning criteria. The FDA method has a broad application prospects in coal and gas outburst prediction.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.430-430
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• 2011

최근 지구온난화, 엘리뇨 및 라니냐 등 지구환경 변화에 따른 기후변화의 영향으로 짧은 시간에 매우 높은 강도를 가진 이상호우에 의해 많은 인명과 재산피해가 발생하고 있다. 우리나라의 경우에도 1990년대 후반부터 과거와 달리 국지적 집중호우가 빈번히 발생하고 있으며 집중호우에 의한 홍수는 우리나라의 가장 빈번한 자연재해 중 하나가 되었다. 이러한 성격의 홍수는 소유역 규모의 좁은 지역과 급경사지역에서 짧은 지속시간과 집중적인 강우강도에 의해 발생하고, 빠른 유속과 토사를 동반하는 빠른 수문반응으로 홍수에 대비할 시간이 부족한 것이 특징이기 때문에 기존의 홍수예보모형을 이용하여 발생홍수의 특성을 예측하기에는 많은 어려움이 있다. 유출수문곡선의 특성을 분석하여 홍수의 특성을 분석하는 연구는 Kyiamah (1996)가 유출수문곡선의 기초적인 상승곡선, 지체시간, 첨두홍수량을 이용하여 돌발홍수사상에 대한 크기를 산정하였으며, 이를 바탕으로 Bhaskar 등 (2000)은 유출수문곡선의 상승부 기울기, 첨두 홍수량비, 홍수 반응시간을 이용하여 돌발홍수지수(Flash Flood Index)를 산정하고 이 지수에 의해 돌발홍수를 설명하고자 하였다. 국내에서는 정재철 (2000)이 보청천을 대상으로 단 몇 개의 사상만을 대상으로 Bhaskar 등 (2000)이 제시한 돌발홍수지수를 적용한 바가 있다. 그러나, 이들 연구에서는 소수의 수문사상만을 이용하였기 때문에 상대심도를 산정하는데 있어 문제가 있으며 상대심도를 산정하는데 있어 각 심도계수들의 임의적인 도수분포를 이용하였기 때문에 매우 주관적이라고 할 수 있다. 김병식 등 (2008)은 한강유역의 과거 101개의 홍수사상에 대해 돌발홍수의 상대심도를 파악하기 위하여 돌발홍수지수를 산정하고 2006년 7월의 집중호우에 의해 발행한 홍수사상의 돌발홍수 심도를 시간 및 공간적으로 정량화하였다. 이러한 기존의 연구는 홍수심도 산정시에 필요한 유출수문곡선을 실측된 자료를 이용하여 산정하였으나 국내의 소유역의 경우 실측된 유출수문곡선 자료가 그다지 많지 않은 관계로 인해 홍수심도를 산정하는데 많은 어려움을 내포하고 있다. 따라서 본 연구에서는 미계측 소유역중 시범유역을 선정하고 30년 이상 장기간 실측 강우의 기왕최대 시강우량 자료에 대하여 강우-유출모형을 통한 홍수유출수문곡선을 모의한 후, 빈도별 확률강우량에 대한 수문곡선 특성인자들의 비를 무차원 지수화하여 극한홍수사상에 대한 설계강우의 취약성을 평가하기 위한 홍수위험지수 (Flood Hazard Index) 산정방법을 제시하였다.

• Gut and Liver
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• v.12 no.6
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• pp.633-640
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• 2018

Background/Aims: Obesity is a risk factor for gastroesophageal reflux disease (GERD), with several studies demonstrating positive associations between body mass index (BMI) and GERD symptoms. However, little is known about the effect of BMI changes on erosive esophagitis (EE). In this study, we investigated whether BMI reduction could resolve EE. Methods: A retrospective cohort study was performed to assess the natural course of EE according to changes in BMI. Participants undergoing health check-ups from 2006 to 2012 were enrolled, and 1,126 subjects with EE were included. The degree of esophagitis was measured by upper endoscopy and serially checked over a 5-year follow-up. Logistic regression and Cox proportional hazards models were used to investigate the association between BMI reduction and EE resolution. Results: Substantial weight loss is associated with EE resolution. The adjusted odds ratio for EE resolution was 1.44 (95% confidence interval [CI], 1.09 to 1.92) among participants with a decrease in BMI compared to those with no decrease in BMI. The EE resolution rate was related to the degree of BMI reduction. The effect of weight loss on EE resolution was higher among subjects who lost more weight. Compared with subjects with no decrease in BMI, the hazard ratios for EE resolution were 1.09 (95% CI, 0.89 to 1.35), 1.31 (95% CI, 1.01 to 1.72) and 2.12 (95% CI, 1.44 to 3.12) in subjects with BMI reductions of ${\leq}1$, 1-2, and >$2kg/m^2$, respectively. Conclusions: EE resolution is associated with a decrease in BMI, and weight loss is potentially an effective GERD treatment.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.158-158
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• 2018

Drought is a recurrent natural hazard in Bangladesh. It has significant impacts on agriculture, environment, and society. Well-timed information on the onset, extent, intensity, duration, and impacts of drought can mitigate the potential drought-related losses. Thus, drought characteristics need to be explained in terms of frequency, severity, and duration. This paper aims to characterize the spatial and temporal pattern of meteorological drought using EDI and illustrated drought severity over Bangladesh. Twenty-seven (27) station-based daily rainfall data for the study period of 1981-2015 were used to calculate the EDI values over Bangladesh. The evaluation of EDI is conducted for 4 sub-regions over the country to confirm the historical drought record-developed at the regional scale. The finding shows that on average, the frequency of severe to extreme drought is approximately 0.7 events per year. As a result of the regional analysis, most of the recorded historical drought events were successfully detected during the study period. Additionally, the seasonal analysis showed that the extreme droughts were frequently hit in northwestern, middle portion of the eastern and small portion of central parts of Bangladesh during the Kharif(wet) and Rabi(dry) seasons. The severe drought was affected recurrently in the central and northern regions of the country during all cropping seasons. The study also points out that the northern, south-western and central regions in Bangladesh are comparatively vulnerable to both extreme and severe drought event. The study showed that EDI would be a useful tool to identify the drought-prone area and time and potentially applicable to the climate change-induced drought evolution monitoring at regional to the national level in Bangladesh. The outcome of the present study can be used in taking anticipatory strategies to mitigate the drought damages on agricultural production as well as human sufferings in drought-prone areas of Bangladesh.

• Journal of Periodontal and Implant Science
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• v.49 no.3
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• pp.158-170
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• 2019

Purpose: This study investigated the association between health status and tooth loss based on data from the National Health Insurance Service-Health Examinee Cohort in 2002-2015. Methods: Multivariate Cox proportional hazards regression analyses were applied to a longitudinal retrospective database, which was updated and newly released in 2018, to assess the association between health status and tooth loss while adjusting for potential confounders among sociodemographic and economic factors (sex, age, household income, insurance, and presence of disability), general and oral health status (body mass index [BMI], smoking and drinking status, periodic dental visits and scaling, and brushing before sleep), and comorbid disease (hypertension, diabetes mellitus [DM], and Charlson comorbidity index [CCI]). Results: Among 514,866 participants from a South Korean population, 234,247 (45.5%) participants satisfying the inclusion criteria were analyzed. In the adjusted multivariate analysis, sex, age, household income, insurance, presence of disability, BMI, smoking and drinking status, periodic scaling, tooth brushing before sleep, DM, and CCI showed statistically significant associations with the loss of at least 1 tooth. The risk of experiencing a loss of ${\geq}4$ teeth was associated with an increase in age (in those 50-59 years of age: hazard ratio [HR], 1.98; 95% confidence interval [CI], 1.93-2.03; in those 60-69 years of age: HR, 2.93; 95% CI, 2.85-3.02; and in those 70-79 years of age: HR, 2.93; 95%, CI 2.81-3.05), smoking (HR, 1.69; 95% CI, 1.65-1.73), and DM (HR, 1.43; 95% CI, 1.38-1.48). Conclusions: The results of this study showed that the risk of experiencing tooth loss was related to multiple determinants. DM and smoking were especially significantly associated with tooth loss.

• Korean Circulation Journal
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• v.48 no.11
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• pp.989-999
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• 2018

Background and Objectives: We aimed to compare outcomes of complete revascularization (CR) versus culprit-only revascularization for ST-segment elevation myocardial infarction (STEMI) and multivessel disease (MVD) in the $2^{nd}$ generation drug-eluting stent (DES) era. Methods: From 2009 to 2014, patients with STEMI and MVD, who underwent primary percutaneous coronary intervention (PCI) using a $2^{nd}$ generation DES for culprit lesions were enrolled. CR was defined as PCI for a non-infarct-related artery during the index admission. Major adverse cardiovascular event (MACE) was defined as cardiovascular (CV) death, non-fatal myocardial infarction, target lesion revascularization, or heart failure during the follow-up year. Results: In total, 705 MVD patients were suitable for the analysis, of whom 286 (41%) underwent culprit-only PCI and 419 (59%) underwent CR during the index admission. The incidence of MACE was 11.5% in the CR group versus 18.5% in the culprit-only group (hazard ratio [HR], 0.56; 95% confidence interval [CI], 0.37-0.86; p<0.01; adjusted HR, 0.64; 95% CI, 0.40-0.99; p=0.04). The CR group revealed a significantly lower incidence of CV death (7.2% vs. 12.9%; HR, 0.51; 95% CI, 0.31-0.86; p=0.01 and adjusted HR, 0.57; 95% CI; 0.32-0.97; p=0.03, respectively). Conclusions: CR was associated with better outcomes including reductions in MACE and CV death at 1 year of follow-up compared with culprit-only PCI in the $2^{nd}$ generation DES era.

• Clinical and Experimental Pediatrics
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• v.62 no.1
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• pp.30-35
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• 2019

Purpose: Obesity is risk factor for nonalcoholic fatty liver disease (NAFLD). However, nonobese patients are also increasingly susceptible to NAFLD. The aim of this study was to compare the clinical characteristics of obese and nonobese pediatric patients with NAFLD. Methods: We retrospectively studied 68 patients who were diagnosed with NAFLD between January 2010 and October 2016 at 10-18 years of age. Body mass index ${\geq}95th$ percentile for age and sex was defined as obesity. Abdominal ultrasonography and laboratory, anthropometrics measurements were evaluated. Results: Among the 68, 26 (38.2%) were nonobese patients. The ratio of male to female was 5.8:1, and the median age at diagnosis was 13 years (range, 10-17 years). Significant higher triglyceride (223.0 mg/dL vs. 145.9 mg/dL, P=0.047) and total cholesterol levels (211.6 mg/dL vs. 173.2 mg/dL, P=0.011) were shown in nonobese than obese patients. High-density lipoprotein cholesterol level <40 mg/dL (hazard ratio [HR], 6.5; 95% confidence interval [CI], 2.13-7.10; P=0.048), total cholesterol level >200 mg/dL (HR, 5.6; 95% CI, 1.23-15.31; P=0.038) and abdominal obesity (HR, 2.53; 95% CI, 1.22-4.68; P=0.013) were significant risk factors for NAFLD in nonobese patients. Conclusion: Nonobese patients present a substantial proportion of pediatric NAFLD cases. Significant abnormal lipid concentrations were found in nonobese and abdominal obesity was important risk factor for nonobese NAFLD.

• Journal of Preventive Medicine and Public Health
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• v.55 no.5
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• pp.475-484
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• 2022

Objectives: This study aimed to determine the association between metabolic syndrome (MetS) and the incidence of colorectal cancer (CRC) in Korean women with obesity. Methods: Cancer-free women (n=6 142 486) aged 40-79 years, who underwent National Health Insurance Service health examinations in 2009 and 2010 were included. The incidence of CRC was followed until 2018. The hazard ratio (HR) of MetS for the incidence of colon and rectal cancer was analyzed according to body mass index (BMI) categories, adjusting for confounders such as women's reproductive factors. In addition, the heterogeneity of associations across BMI categories was assessed. Results: Women with MetS were at increased risk of colon and rectal cancer compared to women without MetS (HR, 1.20; 95% confidence interval [CI], 1.16 to 1.23 and HR,1.15; 95% CI, 1.11 to 1.20), respectively. The HR of MetS for colon cancer across BMI categories was 1.12 (95% CI, 1.06 to 1.19), 1.14 (95% CI, 1.08 to 1.20), and 1.16 (95% CI, 1.12 to 1.21) in women with BMIs <23.0 kg/m², 23.0-24.9 kg/m², and ≥25.0 kg/m², respectively. The HR of MetS for rectal cancer across corresponding BMI categories was 1.16 (95% CI, 1.06 to 1.26), 1.14 (95% CI, 1.05 to 1.23), and 1.13 (95% CI, 1.06 to 1.20). The heterogeneity of associations across BMI categories was not significant in either colon or rectal cancer (p=0.587 for colon cancer and p=0.927 for rectal cancer). Conclusions: Women with MetS were at increased risk of colon and rectal cancer. Clinical and public health strategies should be considered for primary CRC prevention with an emphasis on improving women's metabolic health across all BMI groups.