• 대한전기학회논문지:전력기술부문A
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• 제49권4호
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• pp.177-184
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• 2000

In this paper, we proposes a method for assessing the effect of voltage sag in power distribution systems using fuzzy model. The proposed method is based on the reliability data of distribution system and specified computer business equipment manufacturer association(SCBEMA) curve that express the representative power acceptability curve by voltage sag for each customer type. The SCBEMA curves are made by using the CBEMA curves obtained from the experiment for the customers sensitive equipment. In order to transform SCBEMA curves to the differential damage by voltage sag, a fuzzy model is used. The proposed fuzzy model is composed to reflect two parameters of customers damage by voltage sag. One is the duration and magnitude of voltage sag and the other is the different risk due to the customer types. The Monte Carlo simulation method and the historical reliability data in KEPCO ae used for case studies.

• 대한임상검사과학회지
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• 제44권2호
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• pp.75-80
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• 2012

Papillary thyroid carcinoma (PTC) is the most common thyroid cancer, accounting for 95% or more of malignancies in Korea. Recently, many thyroid cancers have been detected owing to the widespread use of ultrasonography in health surveillance. The objective of this study was to evaluate the association of known prognostic factors with the $BRAF^{V600E}$ mutation and its association features in Korean patients with papillary thyroid carcinomas. The $BRAF^{V600E}$ mutation was detected in 69.1% (256 of 370) of PTC cases. In univariate analysis, the $BRAF^{V600E}$ mutation was significantly associated with tumor size (p < 0.05) and sex. However, it was not significantly associated with other established risk factors, such as age, extrathyroidal extension, and lymph node metastasis. This finding supports the idea that the BRAF mutation plays a role in the early stage of PTC development. This relationship deserves further investigation to clarify whether $BRAF^{V600E}$ is a useful risk factor or prognostic marker for PTC.

• 한국환경과학회지
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• 제33권2호
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• pp.169-178
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• 2024

This study aimed to investigate the impact of pavement design changes on user perceptions, with the objective of enhancing safety in urban streetscape. A total of 72 participants were recruited, and the study focused on alleyways in areas with a high risk of crime. Employing the Semantic Differential (SD) methodology, an assessment was conducted to gauge participants' perceptions of three different pavement types (A-type, B-type, C-type) as well as the existing pavement. The results indicated that the C-type pavement, characterized by vibrant and harmonious color palettes and patterns, elicited the highest levels of perceived safety, comfort, and openness among users. This signifies that physical environmental improvements through color design can mitigate the feelings of insecurity and foster emotional stability. Therefore it is recommended to implement various color schemes and pattern designs to road surface for enhancing user safety in high-risk urban areas.

• 한국융합학회논문지
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• 제13권2호
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• pp.67-75
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• 2022

이 연구의 목적은 현재 운영되고 있는 코로나19 예방을 위한 거리두기 체계의 과학적 근거 보완으로 적절한 관리방안을 제시하고자 함이다. 현재의 수리 모델들은 연립 상미분방정식으로 표현되어 소상공인이나 영세업자들의 출입자 관리에 사용하기는 어려운 문제가 있다. 본 고에서는 이러한 점을 보완하기 위하여 집합 공간에 주어지는 허용위험도와 기초감염재생산지수, 백신접종에 의한 위험도 감소율을 고려하여 집합하는 사람들에 의한 감염위험도를 정량적으로 표현하는 방법을 제시하였다. 백신접종 상황(미접종, 1차 접종, 완전 접종)에 따른 감염 위험성 정도와 바이러스의 유행상황을 함께 고려하여 방문자의 집합에 따른 감염자 발생 가능성을 확률론적인 차원에서 관리하는 간단한 정량적 모델을 개발하였다. 모델을 사용하여 주어진 예에서 20%의 미접종자가 완전 접종으로 전환될 경우 위험도는 55% 수준으로 감소되는 것을 보였고, 기초 감염재생산지수와 백신접종에 의한 감염위험도 감소 개선 효과를 비교하여 의학적인 관리보다 방역 측면에서의 관리가 더 큰 효과를 얻을 수 있다는 점을 제시하였다. 이를 바탕으로 백신의 종류와 확진자 발생 정도를 고려한 다양한 상황에서 적용할 수 있는 일반화 모델도 제시하였다. 이 모델을 적용하면 백신의 종류, 접종 정도, 접종 후 시간 경과에 따른 실시간 개인별 위험도를 산출할 수 있고, 이를 통해 주어진 공간의 집합 인원에 따른 위험도 관리에 이용할 수 있다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권8호
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• pp.3101-3109
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• 2015

Background: Methylenetetrahydrofolate reductase (MTHFR) is involved in amino acid synthesis and DNA function. Two common polymorphisms are reported, C677T and A1298C, that are implicated in a number of human diseases, including cancer. Objective: The association between MTHFR C677T and A1298C genotype and haplotype frequencies in risk for lung cancer (LC) was investigated in the Jordanian population. Materials and Methods: A total of 98 LC cases were studied for MTHFR C677T and A1298C polymorphisms, compared to 89 controls taken from the general population, employing the PCR-RFLP technique. Results: The frequency of the genotypes of MTHFR C677T among Jordanians was: CC, 59.6%, CT, 33%; and TT, 7.4% among LC cases and 49.4%, 40.2% and 10.3% among controls. No significant association was detected between genetic polymorphism at this site and LC. At MTHFR A12987C, the genotype distribution was AA, 29.5%; AC, 45.3%, and CC 25.3% among LC cases and 36.8%, 50.6% and 12.6% among controls. Carriers of the CC genotype were more likely to have LC (OR=2.5; 95%CI: 1.04-6; p=0.039) as compared to AA carriers. Smokers and males with the CC genotype were 9.9 and 6.7 times more likely to have LC, respectively ($OR_{smokers}=9.9$; 95%CI: 1.2-84.5, p=0.018; $OR_{men}=6.6$; 95%CI: 1.7-26.2, p=0.005). Haplotype analysis of MTHFR polymorphism at the two loci showed differential distribution of the CC haplotype (677C-1298C) between cases and controls. The CC haplotype was associated with an increased risk for lung cancer (OR=1.6; 95% CI: 1.03-2.4, p=0.037). Conclusions: The genetic polymorphism of MTHFR at 1298 and the CC haplotype (risk is apparently lower with the C allele at position 677) may modulate the risk for LC development among the Jordanian population. Risk associated with the 1298C allele is increased in smokers and in males. The results indicate that a critical gene involved in folate metabolism plays a modifying role in lung cancer risk, at least in the Jordanian population.

• Journal of Preventive Medicine and Public Health
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• 제50권3호
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• pp.195-200
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• 2017

Objectives: Q fever is a zoonotic disease that occurs worldwide; however, little is known about its prevalence in South Korea. We attempted to determine the prevalence of Q fever seroreactivity among Korean slaughterhouse workers and the risk factors for seroreactivity according to the type of work. Methods: The study was conducted among 1503 workers at a total of 73 slaughterhouses and 62 residual-product disposal plants. During the study period, sites were visited and surveys were administered to employees involved in slaughterhouse work, and serological tests were performed on blood samples by indirect immunofluorescence assays. Serological samples were grouped by job classification into those of slaughter workers, residual-product handlers, inspectors and inspection assistants, and grading testers and testing assistants. Employee risk factors were analyzed according to the type of work. Results: Out of 1481 study subjects who provided a blood sample, 151 (10.2%) showed reactive antibodies. When these results were analyzed in accordance with the type of work, the result of slaughter workers (11.3%) was similar to the result of residual-product handlers (11.4%), and the result of inspectors and assistants (5.3%) was similar to the result of grading testers and assistants (5.4%). Among those who answered in the affirmative to the survey question, "Has there been frequent contact between cattle blood and your mouth while working?" the proportions were 13.4 and 4.6%, respectively, and this was identified as a risk factor that significantly varied between job categories among slaughterhouse workers. Conclusions: This study found a Q fever seroreactivity rate of 10.2% for slaughterhouse workers, who are known to be a high-risk population. Contact with cattle blood around the mouth while working was the differential risk factor between job categories among slaughterhouse workers.

• Safety and Health at Work
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• 제6권2호
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• pp.114-119
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• 2015

Background: There has been considerable interest in Japanese society in the problem of work-related stress leading to depressive symptoms, and an increasing number of primary houseworkers maintain paid employment. The purpose of this study was to examine the differential impact of multiple roles associated with psychological distress among Japanese workers. Methods: We studied 722 men and women aged 18-83 years in a cross-sectional study. The K10 questionnaire was used to examine psychological distress. Results: The proportion of participants with psychological distress was higher in women (17.8%) compared with men (11.5%). Having three roles significantly decreased the risk of psychological distress [women: odds ratio (OR), 0.37-fold; men: OR, 0.41] compared with only one role. In working married women, there was significantly less psychological distress (OR, 0.27), and those with childrearing or caregiving responsibilities for elderly parents had significantly less psychological distress (OR, 0.38) than those with only an employment role. Similarly, working married men who had childrearing or caregiving responsibilities for elderly parents had significantly less psychological distress (OR, 0.41) than those who had only an employment role. Conclusion: The present study demonstrated that participants who had only an employment role had an increased risk of psychological distress. The degree of psychological distress was not determined solely by the number of roles. It is important to have balance between work and family life to reduce role conflict and/or role submersion, which in turn may reduce the risk of psychological distress.

• Asian Pacific Journal of Cancer Prevention
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• 제17권5호
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• pp.2643-2648
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• 2016

Background: High-sensitivity C-reactive protein (hsCRP) levels are lower in Japanese compared with Western subjects. Since it is uncertain whether hsCRP is a potent predictor of mortality at low CRP concentrations, the present study examined associations with all-cause and cause-specific mortality in a large population of Japanese. Materials and Methods: Subjects were 4,737 men and 6,343 women aged 49-76 years participating in the baseline survey of an ongoing cohort study of lifestyle-related diseases between February 2004 and July 2006. Hazard ratios for all-cause and cause-specific mortality associated with hsCRP levels were estimated using Cox proportional hazards regression. Results: A total of 436 all-cause deaths occurred during a median follow-up of 8 years. The main cause of death was cancer. In men, hsCRP levels were positively associated with the risk of all-cause mortality as well as deaths from cancer and cardiovascular disease (CVD). All-cause mortality hazards for the 2nd (0.34-0.84 mg/L) and the 3rd (${\geq}0.85mg/L$) tertiles of hsCRP were 1.27 (95% confidence interval [CI], 0.93-1.73) and 1.75 (1.30-2.37), respectively (p for trend=0.001). In women, increased risk of all-cause and cause-specific mortality associated with elevated hsCRP levels was observed, but the associations were not statistically significant. Conclusions: HsCRP may be an independent predictor of all-cause, cancer and CVD mortality in apparently healthy Japanese men, but not women. The differential effect of hsCRP in predicting mortality risk by sex warrants further investigation.

• 한국화재소방학회논문지
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• 제13권4호
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• pp.7-12
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• 1999

석유 화학플랜트에서 다량 부산되는 가연성 고체인 EVA(ethyl vinyl acetate) 분진의 열적특성 및 산화제와의 혼촉 위험성을 조사하였다. 시차주사열량계(DSC, Differential Scanning calorimeter) 및 열중량 분석기(TGA, Thermogavimetric Analysis)를 이용하여 온도에 따른 발열개시온도 및 중량감소를 조사하였고, EVA 분진의 위험성을 살펴보고자 몇 가지 대표적인 산화제와 혼합하여 무게비에 따른 압력용기 내에서의 혼촉 위험성을 조사하였다. DSC 분석 결과 EVA 분진의 열분해에 따른 발열 peak가 220~$250^{\circ}$ 부근에서 나타나고 있으며, TGA 분석결과 EVA 분진의 분해온도는 250~$500^{\circ}$ 범위이다. 압력 용기 시험에 의한 산화제와 EVA 분진의 혼촉 위험성은 오리피스 직경이 감소할수록 증가하며, 승온속도가 증가할수록 증가한다. 또한 승온속도가 느린 경우에는 시료의 분해온도와 산화제의 분해온도가 비슷한 경우 혼촉 위험성이 크게 나타났으며, 승온속도가 빠른 경우에는 시료 및 산화제의 분해온도보다는 분자 내에 산소의 함유량이 높은 산화제가 혼촉 위험성이 크게 나타났다.

• 한국융합학회논문지
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• 제11권2호
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• pp.375-384
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• 2020

성인의 음주패턴과 우울경험의 관련성을 확인하고, 남녀 문제음주자의 우울경험 관련 요인을 파악하고자 실시되었다. 국민건강영양조사(2010-2013년)의 만 19세 이상 성인 19,878명의 자료를 사용하여 문제음주자의 우울경험 관련요인 파악을 위해 복합표본 로지스틱 회귀분석하였다. 남녀 모두 문제음주 수준이 높아질수록 우울경험의 위험이 증가하는 양 반응관계를 보였다. 남성 문제음주자의 우울경험의 위험은 높은 연령군, 낮은 교육군, 비고용군, 스트레스 인지군, 주관적 불건강 상태군에서 높았고, 기혼군에서 낮았다. 여성 문제음주자의 우울경험의 위험은 40대 연령군, 낮은 교육군, 비고용군, 스트레스 인지군, 주관적 불건강 상태군에서 높았다. 따라서 우울 위험군인 문제음주자를 조기에 발견하여 정신건강 문제로 진행되지 않도록 예방 활동을 확대하고, 문제음주와 우울관리 접근시 성별에 따른 차별화된 전략이 요구된다.