다이옥신의 건강효과

정해관,Cheong, Hae-Kwan 대한예방의학회 2003 예방의학회지 Vol.36 No.4

화학공장 근로자들의 간기능 이상 유병률 및 위험인자에 관한 연구

정해관,김정순,Cheong, Hae-Kwan,Kim, Joung-Soon 대한예방의학회 1997 예방의학회지 Vol.30 No.1

The object of this study is to evaluate the possibility of chemical-induced liver disorder among workers exposed to various chemicals and to classify the the liver function abnormalities by causes and to analyse the risk factors for each liver disorders. A cross-sectional study including questionnaire survey, physical examination, laboratory tests and ultrasonography of liver was conducted on 1,126 workers, 459 workers in a coal chemical plant(company A) and 667 workers in an insulation material manufacturing factory(company B). An industrial hygienist reviewed the chemicals used in both companies and evaluated the work environments to classify the workers by chemical exposure semiquantitatively. The results are as follows: 1. Of 459 workers in company A, 83 workers(18.1%) are classified as nonexposed, group 163(35,5%) as short-term exposure group, 155(33.8%) as intermediately exposed group and 58(12.6%) as long-term exposed group bared on the mean daily exposure to hepatotoxic chemicals evaluated by an industrial hygienist. Of 667 workers in company B, 484(72.6%) workers were classified as nonexposed and 183(35.5%) as exposed group. 2. Workers with SGOT level higher than 40 IU/l were (10.0%) in company A and 77(11.5%) in company 3, and those with SGPT level higher than 35 IU/l were 118(25.7%) in company A and 198(29.7%) in company B. The differences were not significant between companies and between exposure groups(p>0.05). Workers with $\gamma-GT$ level higher than 62 IU/l were 29(6.3%) in company A and 77(11.5%) in company B (p<0.01). The difference between exposure groups was not significant(p>0.05) within companies. Workers with liver function abnormalities(defined as SGOT higher than 40 IU/l or SGPT higher than 35 IU/l) were 338(30.0%) among 1,126 workers. Of 338 workers with live. function abnormalities 139(12.3%) had fatty liver by ultrasonography, 79(7.0%) had alcoholic liver(defined as workers with liver function abnormalities with weekly alcohol consumption greater than 280 g for more than 5 years), 54(4.8%) had hepatitis B, 12(1.1%) had hepatitis C and the other 114(33.7%) was not otherwise classified. Prevalences of alcoholic liver and fatty liver were significantly lower in company A(prevalence ratio 0.24 for alcoholic liver, p<0.001, prevalence ratio 0.76 for fatty liver, p<0.05) but prevalences of liver disorders between exposure groups within companies were not significant(p>0.05). 3. Summary prevalence ratios(SPR) of live. function abnormalities, fatty live. and other liver disorders, adjusted by age and company were not significantly higher in exposed group in any chemicals(p>0.05) but in some chemicals, SPRs were significantly lower. 4. On simple analysis of risk factors for liver function abnormalities, prevalence odds ratio(POR) of those with age between 30 and 39 was 1.54(p<0.01) and those with age ever 40 was 1.51(p<0.01). POR of those with histories of liver disorders and general anesthesia was 1.77(p<0.001) and 4.02 for those with overweight and 6.23 for those with obesity, defined by body mass index(p<0.001). 5. On logistic regression analysis, risk factors of liver function abnormality were fatty liver(POR 2.92 for grade 1, 12.15 for grade 2), presence of hepatitis B surface antigen(POR 3.62) and obesity(POR 5.38 for overweight and 16.52 for obesity). Presence of hepatitis B surface antigen(POR 0.18) was the only preventive facto. of fatty live. Company(POR 0.30) and obesity(POR 2.49 for overweight, 4.52 for obesity) were related to the alcoholic live. Obesity(POR 2.94 for overweight) was the only significant risk factor of hepatitis B and there was no significant risk factor for liver function abnormality not otherwise classified. It is concluded that the evidence of liver disorder related with chemical exposure is not evident in these factories. It is also postulated that fatty liver and alcoholic liver is most common causes of liver function abnormalities among workers and effort for w

특수건강진단에서 발견된 고혈압 및 간질환 유소견자의 건강관리 실태에 관한 조사

정해관,김정순,문옥륜,임현술,Cheong, Hae-Kwan,Kim, Joung-Soon,Moon, Ok-Ryun,Lim, Hyun-Sul 대한예방의학회 1992 Journal of Preventive Medicine and Public Health Vol.25 No.4

Authors studied the workers' knowledge about the health problems detected through the previous workers' periodic health examination, content of follow-up management ana actions taken for their health problem detected on previous health examination. From June to September 1992, workers' periodic health examination was peformed on workers employed in 10 companies located in 2 middle-sized Korean cities. A questionnaire survey was done far 150 workers who reported to have $D_2$ result of either hypertension or liver disorder at the previous workers' periodic health examination done in 1991. The results are as follows; 1. Of 160 workers who had $D_2$ result of either hypertension or liver disorder in previous examination one year before, only 85 workers(51.3%, 43 workers with hypertension, 38 workers with live disorder) responded that they have such disorders. The other 65 workers responded to questionnaire were all those with C results. Respondents' knowledge about their diagnoses was relatively precise (95.2% in hypertension group, 94.6% in liver disorder group) but knowledge about classification of diseases was poor. 2. The main efforts to solve the health problem nab self management (20 spells, 55.3%), visiting clinic or hospital(6 spells, 12.8%), use of herb medicine (2 spells, 4.3%) and use of drug store(2 spells, 4.3%) in hypertension group. In liver disorder group, 30 spells (71.4%) relied on self management,6 spells (14.3%) on hospital or clinic and 9 spells (21.4%) had no effort to improve the health problem. Content of self management was low salt diet, quit smoking, regular exercise and quit alcohol drinking in order. Avoidance of salt in diet was high in hypertension group and quitting alcohol drinking was high in liver disorder group. In those with self management, 80.7% of hypertension group and 83.3% of liver disorder group continued previous effort. Those, however, who utilized clinic or hospital, only 16.7% and 50.0% were still visiting hospital or clinic. 3. Fifty seven percent of hypertension group and 64.3% of liver disorder group was presently smoking,8.5% and 11.9% reduced smoking and 21.3% and 14.3% stopped smoking. Forty nine percent of hypertension group and 28.6% of liver disorder group was presently drinking. Reduced alcohol intake was reported in 29.8% and 40.5%, 12.8ole and 23.8% stopped alcohol drinking. Sixty six percent of hypertension group and 73.8% of liver disorder group did no regular exercise, but 12.8% and 11.9% of each group increased their physical exercise far last one year. Forty three percent of hypertension group and 38.l% of liver disorder group was overweight (defined by bodymass index greater or equal than 25). Reduced body Weight was reported in 17.2% and 16.7% of each group. Reduced dietary salt intake was high in hypertension group (51.5%). The study results suggest that follow-up management after workers' periodic health examination is not satisfactory. In order to improve this situation, adequate information on the result of the workers' periodic health examination should be distributed to each worker group with health education and counselling.

근로자 건강진단시 간기능 이상자의 정밀검사항목 개선을 위한 조사연구

정해관,임현술,김규회,Cheong, Hae-Kwan,Lim, Hyun-Sul,Kim, Gyu-Hoi 대한예방의학회 1994 Journal of Preventive Medicine and Public Health Vol.27 No.4

Workers' periodic health examination is the main tools used to manage the health problems of most workers in Korea. The most common health problem found in workers' periodic health examination is liver disorder. Liver disorder is also one of the most common health problems in general population and one of the leading causes of mortality in adult population. Regulation proposed by government (No. 207, Ministry of Labor, 1992) defines the criteria for selection of workers with the liver dysfunction for further evaluative examination and the examination items used for diagnosis of the workers with liver dysfunction. This study was designed to evaluate the proficiency of each examination items presently defined in Regulation and propose the optimal examination items for detection of the liver disorders found by workers' periodic health examination. Study subjects are 186 workers with abnormal liver function tests in screening examination of workers' periodic health examination. Questionnaire survey including past history of liver disorder, drinking history, height and weight was done. Physical examination by physician, routine test items defined by Regulation (SGOT, SGPT, $\gamma$-GTP, protein, albumin, total and direct bilirubin, alkaline phosphatase, $\alpha$-feto protein, HBsAg and anti-HBs), anti-HCV antibody test and liver ultrasonography were done. Results are as follows; 1. Result of evaluative examination utilizing only the items defined in Regulation was; There were 75 workers with suspected live. disorder(40.3%), 63 with no liver dysfunction (33.9%), 13 with suspected hepatitis B(7.0%), 10 workers with hepatitis B(5.4%), 10 workers with hepatitis B carrier state(5.4%), 10 with alcoholic liver disorders(5.4%), 5 with fatty liver(2.7%). When alternative diagnostic criteria applying additional examination items (drinking history, body mass index, anti-HCV antibody and ultrasonography) diagnosability of liver disorder was increased. When all four items were included, final results were; 23 workers (17.8%) with hepatitis B (10 carriers, 13 suspects and 10 hepatitis B), 10 (5.4%) with hepatitis C(4 carriers, 5 suspects and 1 hepatitis C), 13(7.0%) with alcoholic liver disorder, 45(24.2%) with fatty liver (40 suspects, 5 fatty liver), 410%) with suspected liver disorders and 44 (23.7%) with normal liver. 2. Of examination items defined by Regulation, only SGOT, SGPT, $\gamma$-GTP and HBsAg were significantly different in abnormal rate and mean value, and all other laboratory findings did not showed significant difference between two groups. Drinking history, body mass index and anti-HCV antibody test which are the items that authors included in this study, also showed significant difference between two groups. Utilization of body mass index (BMI) for abnormal liver function group in diagnosis of fatty liver had high specificity (97.6%) but sensitivity (22.3%) was low. Therefore we suggest that SGOT, SGPT, $\gamma$-GTP, HBsAg, alcohol drinking history, BMI and anti-HCV Ab were useful for diagnosis of liver disorders among worker's periodic health examination.

흡연과 폐암의 역학적 관계 : 역사적 고찰

정해관(Hae-Kwan Cheong) 한국역학회 2005 Epidemiology and Health Vol.27 No.2

Since its introduction to western world in 16th century, smoking has been one of the most popular parts of human life. Its health hazards, however, has rarely been evaluated before mid 20th century. After early suggestion of association with lip cancer and pipe smoking, which was falsely associated with the heat of the pipe smoking, association between rapidly increasing incidence of lung cancer and increasing popularity of smoking habit in the western world has been suggested in late 1940s. Initial case-control studies, in spite of its proneness to various biases, aroused the relevance of the relationship. It was supported by following well-designed case-control studies and new method, cohort studies in both coast of the Atlantic. Consistency of the results of epidemiologic studies and additional support from animal experiments made the causal relationship to be accepted from scientific community, and finally from public and governments. Establishment of criteria of causal relationship was also established in the process of investigation of the relationship between smoking and lung cancer. Smoking is most common cause attributable to lung cancers in most of the world. It is also responsible for the many cancers, including larynx, bladder, oral cavity, esophagus, pancreas, kidney, stomach, liver, and myeloid leukemia; and cardiovascular disorders, respiratory disorders, and other degenerative disorders. Passive (or environmental tobacco) smoking has also been found to be hazardous. Establishment of causal relationship between smoking and lung cancer has been a landmark in the development of epidemiologic methods and concepts, which played the key role in the evaluation of risk factors and preventive intervention on the chronic degenerative disorders.

SystemC기반 CNN 시뮬레이터 구현

김진영 ( Jinyoung Kim ),이승수 ( Seungsu Lee ),김예준 ( Yejun Kim ),임승호 ( Seung-ho Lim ),조상영 ( Sang-young Cho ) 한국정보처리학회 2020 한국정보처리학회 학술대회논문집 Vol.27 No.2

최근 엣지 컴퓨팅과 같은 임베디드 디바이스에서 CNN과 같은 딥러닝 모듈을 수행하기 위해서 하드웨어 설계 및 구현이 많이 진행되고 있다. 이러한 임베디드 시스템에 필요한 CNN모듈을 위한 하드웨어 설계를 위해서 먼저 모델링을 통해서 시뮬레이션이 필요하다. 본 논문에서는 오픈 라이센스를 이용한 RISC-V로 딥러닝 시뮬레이터를 제작하였다. SystemC로 구현된 RISC-V를 Virtual Platform로 시뮬레이터의 제작을 하여 시뮬레이팅을 하였고, SystemC의 특징인 모듈화와 모듈간 통신에 유의하여 시스템을 구성하였다. CNN 알고리즘을 참조하여 Convolution, Activation, Pooling 연산의 기능을 하는 시스템을 구성하였다.

특집 : 세계화와 국민보건 ; 보건학적 관점에서 본 프리온병의 현황과 전망

정해관 ( Hae Kwan Cheong ) 대한보건협회 2008 대한보건연구 Vol.34 No.1

국내 소아 무균성 뇌막염의 전국적 발생 양상

정해관(Hae-Kwan Cheong),박수경(Sue Kyung Park),기모란(Moran Ki),이관(Kwan Lee) 한국역학회 2008 Epidemiology and Health Vol.30 No.2

Background and objectives: Aseptic meningitis is a disease of children with seasonal outbreak in summer. In spite of high morbidity, it is not notifiable without reported nationwide morbidity. The authors estimated incidence of aseptic meningitis and its descriptive characteristics and time- and space-clustering pattern. Subjects and methods: Cases of aseptic meningitis were extracted from National Health Insurance payment request data of National Health Insurance Corporation from January 1996 to December 2001. Cases were classified by region, institution, and hospitalization. Standardized incidence was calculated and compared by the region, month of the year whether there is any clustering. Results: Nationwide incidence of aseptic meningitis among children under 15 years old over the six year period was 3.48 per 1,000 per year. Incidence was higher in female (2.80/1,000) compared to male (4.02/1,000). Age-specific incidence was highest in 5 years old. Annual incidence was highest in 1997 (8.44/1,000) and lowest in 2000 (0.79/1,000) with outbreak every 3 or 4 years. Outbreak was mostly confined in summer months, between May and September. However, seasonal pattern was variable by year. Southern provinces and metropolitan areas had higher incidences and pattern was more prominent in the years with higher outbreak. Time-dependent pattern of the disease from south to north was not prominent. Discussions and conclusions: We have calculated the nationwide incidence of the aseptic meningitis over six year period. In terms of aseptic meningitis, using National Health Insurance data for the estimation of the incidence is a plausible method for the surveillance of the disease.

진드기 매개 감염병의 감염 모형

정해관 ( Hae-kwan Cheong ),김종헌 대한인수공통전염병학회 2018 창립총회 및 학술대회 초록집 Vol.2018 No.1

지뢰제거작업을 위한 가변 형상 무한궤도형 주행 로봇

정해관(Hae-Kwan Jeong),김상도(Sang-Do Kim),이청희(Cheong-Hee Lee),곽윤근(Yoon-Keun Kwak) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.4

This paper introduces a link-type tracked vehicle which is developed for demining operations. The vehicle consists of three parts - front frame, rear frame and body. The front frame is connected to the rear frame by a rotational passive adaptation mechanism which is a driving mechanism of the vehicle. Additionally, the demining system which is adaptable to mobile robot is developed to clear small Anti-Personnel(AP) mines with inexplosive method. In other words, assembled rakes unearth mines by their opposite rotation to the direction of the robot. Finally, the motions of demining rakes and design parameters of the demining system are analyzed.