2002년 봄 서울 지역에 발생한 심한 황사가 일별 사망에 미치는 영향

황승식,권호장,조수헌,Hwang, Seung-Sik,Kwon, Ho-Jang,Cho, Soo-Hun 대한예방의학회 2005 예방의학회지 Vol.38 No.2

Objectives: During the spring of 2002, an unprecedented 2 Asian dust events were experienced in Seoul. On those days, the $PM_{10}$ was surprisingly increased, with daily $PM_{10}$ averages exceeding $600\;and\;700{\mu}g/m^3$ on March 21 and April 8, respectively. Accordingly, public concern relating to the possible adverse health effects of these dust events has increased, as the dust arrives in Korea after having flown over heavily industrialized eastern China. We investigated the effects of these Asian dust events on the mortality during the spring of 2002, in Seoul, Korea. Methods: The total number of deaths per day during the spring of 2002 in Seoul was extracted form the mortality records of the National Statistical Office. We constructed 14 Asian dust days (March 17-March 23, April 7-April 13) and 42 control days during the 56 day study period (March 3-April 27) with respect to the days of the week. The daily average numbers of deaths between the Asian dust and control days were analyzed, with adjustment for meteorological variables and pollutants. Results: The daily PM10 average during the Asian dust weeks was $295.2{\mu}g/m^3$, which was significantly higher than during the control days (p<0.001). The daily average number of deaths from all causes during the Asian dust days was 109.9; 65.6 for those aged 65 years and older, 6.7 from respiratory causes (J00-J99) and 25.6 from cardiovascular causes (I00-I99). The estimated percentage increases in the rate of deaths were 2.5% (95% CI=-5.0-10.6) from all causes; 2.2% (95% CI=-7.4-12.8) for those aged 65 years and older, and 36.5% (95% CI=0.7-85.0) from respiratory causes, but with a 6.1% (95% CI=-19.7-9.7) decrease in deaths from cardiovascular causes. Conclusion: The Asian dust events were found to be weakly associated with the risk of death from all causes. However, the association between dust events and deaths from respiratory causes was stronger. This suggests that persons with advanced respiratory diseases may be susceptible to Asian dust events.

자성유체를 이용한 반능동식 댐퍼에 관한 실험적 연구

황승식,Hwang, Seung-Sik 한국유체기계학회 2004 한국유체기계학회 논문집 Vol.20 No.2

The aim of this study is to provide fundamental information for the development of Semi-Active Damper Using Magnetic fluid. To achieve the aim, the damping effect of magnetic fluid is investigated by experiments that the diameter of inner circular bar and the input amplitude were varied in the magnetic field generated by the permanent magnet and the electromagnet coil. From the study, the following conclusive remarks can be made. As the diameter of inner circular bar and input amplitude increase, the damping effect is improved. This is explained by the fact that as the contact area between inner circular bar and magnetic fluid increases, the increase of friction lowers kinematic energy. If the magnetic field is generated, the damping effect is improved. This is explained the assumption that as the intensity of magnetic fluid particle increases, there is virtual mass phenomenon.

7대 광역시에서 대기오염과 폐암 발생 및 사망에 대한 공간 분석

황승식,이진희,정규원,임정훈,권호장,Hwang, Seung-Sik,Lee, Jin-Hee,Jung, Gyu-Won,Lim, Jeong-Hun,Kwon, Ho-Jang 대한예방의학회 2007 예방의학회지 Vol.40 No.3

Objectives : We aimed to assess the relationship between long-term exposure to air pollution and lung cancer in the Republic of Korea. Methods : Using the Annual Report of Ambient Air Quality in Korea, Annual Report of National Cancer Registration, and Annual Report on the Cause of Death Statistics, we calculated the standardized mortality ratio (SMR) and standardized incidence ratio (SIR) of lung cancer for both sexes in 74 areas from 7 Korean metropolitan cities. We performed random intercept, Poisson regression using empirical Bayes method. Results : Both SMRs and SIRs in the 7 metropolitan cities were higher in women than in men. Mean SIRs were 99.0 for males and 107.0 for females. The association between $PM_{10}$ and lung cancer risk differed according to gender. $PM_{10}$ was not associated with the risk of lung cancer in males, but both incidence and mortality of lung cancer were positively associated with $PM_{10}$ in females. The estimated percentage increases in the rate of female lung cancer mortality and incidence were 27% and 65% at the highest $PM_{10}$ category $({\geq}70\;{\mu}g/m^3)$, compared to the referent category $({\geq}50\;{\mu}g/m^3)$. Conclusions : Long-term exposure to $PM_{10}$ was significantly associated with female lung cancer incidence in 7 Korean metropolitan cities. Further study is undergoing to estimate the relative risk of $PM_{10}$ using multi-level analysis for controlling individual and regional confounders such as smoking and socioeconomic position.

전산유체역학을 이용한 교반 탱크 내에서의 회전유동에 대한 해석 모델의 제안 및 검증

황승식(Seung Sik Hwang),조환용(Cho Hwan Yong),최규홍(Gyuhong Choi),신동훈(Dohghoon Shin),정태용(Tae Yong Chung) 한국에너지학회 2013 에너지공학 Vol.22 No.1

상용 CFD 코드를 이용한 가정용 연료전지의 배열회수용 원심펌프 유동해석에 관한 연구

황승식(Seung Sik Hwang),조지훈(Ji Hoon Jo),진경민(Kyoung Min Jin),이송규(Song Kyu Lee),신동훈(Donghoon Shin),정태용(Tae Yong Chung),박창권(Chang Kwon Park) 한국에너지학회 2011 에너지공학 Vol.20 No.3

공복 혈당과 간암 발생 위험에 관한 코호트 연구

곽진,황승식,고광필,전재관,박수경,장성훈,신해림,유근영,Gwack, Jin,Hwang, Seung-Sik,Ko, Kwang-Pil,Jun, Jae-Kwan,Park, Sue-Kyung,Chang, Soung-Hoon,Shin, Hai-Rim,Yoo, Keun-Young 대한예방의학회 2007 예방의학회지 Vol.40 No.1

Objectives : Chronic infections with hepatitis B or C and alcoholic cirrhosis are three well-known major risk factors for liver cancer. Diabetes has also been suggested as a potential risk factor. However, the findings of previous studies have been controversial in terms of the causal association. Therefore, the aim of this study was to evaluate the association between serum glucose levels and liver cancer development in a Korean cohort. Methods : Thirty-six liver cancer cases were identified in the Korean Multi-Center Cancer Cohort (KMCC). Baseline information on lifestyle characteristics was obtained via questionnaire. Serum glucose levels were measured at the study's enrollment. Relative risks (RRs) were estimated using a Cox proportional hazard regression model. The adjusting variables included age, gender, smoking history, alcohol consumption, body mass index, and hepatitis B surface antigen (HBsAg) seropositivity. Results : The RRs of serum glucose for liver caner were 1.20 (95% CI = 0.48-2.99) for the category of 100 to 125 mg/dL of serum glucose and 2.77 (95% CI = 1.24-6.18) for the >126 mg/dL serum glucose category (both compared to the <100 mg/dL category). In a subgroup analysis, the RR of serum glucose among those who were both HBsAg seronegative and non-drinkers was 4.46 (95% CI = 1.09-18.28) for those with glucose levels >100 mg/dL. Conclusions : The results of this study suggest that a high level of serum glucose can increase liver cancer risk independently of hepatitis infection and drinking history in Koreans. This study implies that glucose intolerance may be an independent risk factor for liver cancer.

공간역학과 환경보건: 공간위치정보 활용에 대한 고찰

한대권,황승식,Han, Dai-Kwon,Hwang, Seung-Sik 한국환경보건학회 2011 한국환경보건학회지 Vol.37 No.1

Recent advances in Geographic Information Systems and spatial statistical and analytical methods, along with the availability of spatially referenced health and environmental data, have created unique opportunities to investigate spatial associations between environment exposures and health outcomes at multiple spatial scales and resolutions. However, the increased use of spatial data also faces challenges, one of which is to ensure certainty and accuracy of locational data that meets the needs of a study. This article critically reviews the use of spatially referenced data in epidemiologic studies, focusing on the issue of locational uncertainty generated from the process of geocoding health and environmental data. Primarily, major issues involving the use of spatially referenced data are addressed, including completeness and positional accuracy, potential source of bias and exposure misclassification, and implications for epidemiologic studies. The need for critical assessment and caution in designing and conducting spatial epidemiology studies is briefly discussed.

수돗물 불소화와 노령 인구의 고관절 골절에 대한 생태학적 연구

박은영,황승식,김재용,조수헌,Park, Eun-Young,Hwang, Seung-Sik,Kim, Jai-Yong,Cho, Soo-Hun 대한예방의학회 2008 예방의학회지 Vol.41 No.3

Objectives : Fluoridation of drinking water is known to decrease dental caries, particularly in children. However, the effects of fluoridated water on bone over several decades are still in controversy. To assess the risk of hip fracture related to water fluoridation, we evaluated the hip fracture-related hospitalizations of the elderly between a fluoridated city and non-fluoridated cities in Korea. Methods : Cheongju as a fluoridated area and Chungju, Chuncheon, Suwon, Wonju as non-fluoridated areas were chosen for the study. We established a database of hip fracture hospitalization episode based on the claims data submitted to the Health Insurance Review Agency from January 1995 to December 2002. The hip fracture hospitalization episodes that satisfied the conditions were those that occurred in patients over 65 years old, the injuries had a hip fracture code (ICD-9 820, ICD-10 S72) and the patients were hospitalized for at least 7days. A total of 80,558 cases of hip fracture hospitalization episodes were analyzed. Results : The admission rates for hip fracture increased with the age of the men and women in both a fluoridated city and the non-fluoridated cities (p<0.01). The relative risk of hip fracture increased significantly both for men and women as their age increased. However, any difference in the hip fracture admission rates was not consistently observed between the fluoridated city and the non-fluoridated cities. Conclusions : We cannot conclude that fluoridation of drinking water increases the risk of hip fracture in the elderly.

SOFC를 위한 고온용 적층단열재 개발

최종균,황승식,최규홍,CHOI, CHONGGUN,HWANG, SEUNG-SIK,CHOI, GYU-HONG 한국수소및신에너지학회 2018 한국수소 및 신에너지학회논문집 Vol.29 No.4

Fuel cells are known as eco - friendly energy facilities that can use heat energy and electric energy at the same time. Fuel cells are classified according to the temperature and material used, and solid oxide fuel cell (SOFC) is relatively high temperature ($700-800^{\circ}C$). SOFC requires a hot box consisting of a high temperature stack, a reformer, a burner, and the heat exchangers in order to use energy efficiently. The hot box needs to maintain heat insulation performance at high temperature to reduce heat loss. However, Fibrous insulation, which is widely used, needs to be improved because it has a disadvantage that the thermal conductivity is rapidly increased due to the increase of temperature. Therefore, this study was carried out to develop a thermal insulation, which is applied to multiple layers insulation (MLI) technic, that can be used under SOFC operating conditions and prevent a drastic drop in thermal conductivity at high temperature. The developed insulation is consist of a thermally conductive material, a spacer, and a reflective plate. The thermal conductivity of the insulation was measured by in the thermal conductivity measuring device at high temperature range. As a result, it was confirmed that the developed layers insulation have an good thermal conductivity (0.116 W/mK) than fibrous insulation (0.24 W/mK) as a radiation shielding effect at a high temperature of 1,173 K.

자궁경부암 검진 수검률의 불평등 추이

장숙랑,조성일,황승식,정최경희,임소영,이지애,강민아,Jang, Soong-Nang,Cho, Sung-Il,Hwang, Seung-Sik,JungChoi, Kyung-Hee,Im, So-Young,Lee, Ji-Ae,KangKim, Min-Ah 대한예방의학회 2007 예방의학회지 Vol.40 No.6

Objectives : While cervical cancer is one of the leading cancers among women worldwide, there are a number of effective early detection tests available. However, the participation rates in cervical cancer screening among Korean women remain low. After the nationwide efforts in 1988 and thereafter to encourage participation in cervical cancer screening, few studies have investigated the effects of socioeconomic inequality on participation in cervical cancer screening. The purpose of this study was to investigate 1) the level of socioeconomic disparities in receiving cervical cancer screening by age group and 2) if there was an improvement in reducing these disparities between 1995 and 2001. Methods : Using data from the Korean National Health Status, Health Behavior and Belief Survey in 1995, the Korean National Health and Nutrition Examination Surveys from 1998 and 2001 (sample sizes of 2,297, 3,738, and 3,283), age-standardized participation rates were calculated according to education level, equivalized household income, and job status. Odds ratios and the relative inequality index (RII) were also calculated after controlling for age. Results : Women with lower education levels were less likely to attend the screening test, and the disparities by education level were most pronounced among women aged 60 years and older. The RIIs among women 60 years and older were 3.64, 4.46, and 8.64 in 1995, 1998, and 2001, respectively. Higher rates of participation were reported among those in the highest income category, which was more notable among the middle aged women (40s and 50s). An inconsistent trend in the rate of participation in cervical cancer screening by occupational level was found. Conclusions : Indicators of socioeconomic position seem to have varying impacts on the inequalities in the rates of participation in cervical cancer screening according to age group. These results demonstrate the need for more aggressive and age-based interventions and policy programs to eliminate the remaining inequalities.