• 한국환경보건학회지
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• 제30권3호
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• pp.283-292
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• 2004

Valid evaluation of community reaction to road-traffic noise exposure is important for the policy making and quality of life. The purpose of this study is to evaluate the relationship between community reaction and nighttime road-traffic noise. The study measured nighttime roadside noise caused by high traffic which is greater than LAeq(22:00-07:00) 65dB(A) and lower than 65dB(A) at Chonju city, from March to April, 2003. Three hundred sixty seven subjects, aged from 20 to 65, were selected from those who are residing close to the major roads. They were asked to answer the questions regarding noise source, stress(PWI-SF), annoyance, disturbance of specific activity, disturbance of sleep, somatic symptom, and four suggested confounding factors. The relationship between annoyance, somatic symptom and noise exposure was not significant. Adjusted odds ratio(95% C.I.) for disturbance of communication　 and disturbance of attention and rest　 were 1.59(1.03-2.71), 1.64(1.06-2.81), respectively. On the other hand sleep disturbance　 was indicated as 1.34(0.77-2.32). The results suggested that federal policy-making about road-traffic noise should consider community reaction evaluated by various perspective including annoyance, disturbance of specific activity, disturbance of sleep, and confounding factors.

• Advances in concrete construction
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• 제6권5호
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• pp.485-507
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• 2018

Concrete-Filled Steel Tube (CFST) columns are an increasingly popular means to support great compressive loads in buildings. The residual strength capacity of CFST stub columns may be utilized to assess the potential damage caused by fire and calculate the structural fire protection for least post-fire repair. Ten specimens under room conditions and 10 specimens under fire exposure to the Eurocode smouldering slow-growth fire were tested to examine the effects of diameter to thickness D/t ratio and reinforcing bars on residual strength capacity, ductility and stiffness of CFST stub columns. On the other hand, in sixteen among the twenty specimens, three or six reinforcing bars were welded inside the steel tube. The longitudinal strains in the steel tube and load-displacement relationships were recorded throughout the subsequent compressive tests. Corresponding values of residual strength capacity calculated using AISC 360-10 and EC4 standards are presented for comparison purposes with the experimental results of this study. The test results showed that after exposure to $750^{\circ}C$, the residual strength capacity increased for all specimens, while the ductility and stiffness were slightly decreased. The comparison results showed that the predicted residual strength using EC4 were close to those obtained experimentally in this research.

• 대한인간공학회지
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• 제32권4호
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• pp.309-319
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• 2013

Objective: The aim of this study is to review and summarize human vibration measurement process, and necessity and methods of frequency weightings for human vibration. Background: Prolonged human exposure to hand-arm vibration and whole-body vibration can result in a range of adverse conditions and the development of occupational diseases such as vibration white finger. For preventing these adverse effects, it is important to correctly apply human vibration measurement process. Method: This manuscript was based on the review and summary of mechanical and human vibration relevant texts, academic papers, materials obtained through web surfing. Results: This manuscript summarizes human vibration measurement process described in ISO standards and relevant texts. The sensitivity of the human body to mechanical vibration is known to be dependent on both the frequency and direction of vibration. To take this into account, varying frequency weighting functions have been developed, and RMS frequency-weighted accelerations are used as the most important quantity to evaluate the effects of vibration on health. ISO provided nine frequency weighting functions in the form of curves and tables. Researches on frequency weightings are focused on development and validation of new frequency weightings to truly reflect the relationship between vibration exposure and its adverse effects. Application: This would be useful information for systematically applying human vibration measurement and analysis process, and for selecting appropriate frequency weighting functions.

• 감성과학
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• 제21권4호
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• pp.103-112
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• 2018

This study aimed to identify specific psychological and brain activation responses relating to the processing of negative emotions in patients with alcohol dependency. The authors hypothesized that patients with alcohol dependency would demonstrate the abnormal functioning of brain regions involved in negative emotions. Eleven male patients diagnosed with alcohol dependence in an inpatient alcohol treatment facility and 13 social drinkers with similar demographics were scanned using functional magnetic resonance imaging (fMRI) as they viewed film clips that evoked negative emotions. During exposure to negative emotional stimuli, the control group evinced significantly greater activity in the right anterior cingulate cortex (ACC) in comparison to patients with alcohol dependency. Correlation analyses demonstrated a negative association in the relationship between beta values from the right ACC and amygdala in participants classified in the control group. No statistically significant relationship was observed for blood oxygenation level-dependent (BOLD) changes between the two regions in the patient group during the elicitation of negative emotions. On the other hand, patients exhibited a greater activation of the amygdala as negative emotions were induced. These results suggest that alcoholism presents pathophysiology of brain activation that is distinct from the responses of healthy individuals functioning as controls.

• 한국환경보건학회지
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• 제37권2호
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• pp.102-112
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• 2011

Objectives: The purpose of this study is to analyze the effects of chronic exposure by welders to manganese (Mn) through an analysis of the degree of brain activity in different activities such as cognition and motor activities using the neuroimaging technique of functional magnetic resonance imaging (fMRI). The neurotoxic effect that Mn has on the brain was examined as well as changes in the neuro-network in motor areas, and the usefulness of fMRI was evaluated as a tool to determine changes in brain function from occupational exposure to Mn. Methods: A survey was carried out from July 2010 to October 2010 targeting by means of a questionnaire 160 workers from the shipbuilding and other manufacturing industries. Among them, 14 welders with more than ten years of job-related exposure to Mn were recruited on a voluntary basis as an exposure group, and 13 workers from other manufacturing industries with corresponding gender and age were recruited as a control group. A questionnaire survey, a blood test, and an fMRI test were carried out with the study group as target. Results: Of 27 fMRI targets, blood Mn concentration of the exposure group was significantly higher than that of the control group (p<0.001), and Pallidal Index (PI) of the welder group was also significantly higher than that of the control group (p<0.001). As a result of the survey, the score of the exposure group in self-awareness of abnormal nerve symptoms and abnormal musculoskeletal symptoms was higher than those of the control group, and there was a significant difference between the two groups (p<0.05, respectively). In the correlation between PI and the results of blood tests, the correlation coefficient with blood Mn concentration was 0.893, revealing a significant amount of correlation (p<0.001). As for brain activity area within the control group, the right and the left areas of the superior frontal cortex showed significant activity, and the right area of superior parietal cortex, the left area of occipital cortex and cerebellum showed significant activity. Unlike the control group, the exposure group showed significant activity selectively on the right area of premotor cortex, at the center of supplementary motor area, and on the left side of superior temporal cortex. In the comparison of brain activity areas between the two groups, the exposure group showed a significantly higher activation state than did the control group in such areas as the right and the left superior parietal cortex, superior temporal cortex, and cerebellum including superior frontal cortex and the right area of premotor cortex. However, in nowhere did the control group show a more activated area than did the exposure group. Conclusions: Chronic exposure to Mn increased brain activity during implementation of hand motor tasks. In an identical task, activation increased in the premotor cortex, superior temporal cortex, and supplementary motor area. It was also discovered that brain activity increase in the frontal area and occipital area was more pronounced in the exposure group than in the control group. This result suggests that chronic exposure to Mn in the work environment affects brain activation neuro-networks.

• 보건교육건강증진학회지
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• 제32권2호
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• pp.1-13
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• 2015

Objectives: This study was conducted to investigate derived factors associated with a public service announcement on handwashing to evaluate the effect of this announcement. Methods: In early september, 1,000 persons over 19 years old was investigated by Computer Aided Telephone Interview, at last 993 persons for analysis. Outcomes were the exposure to the public service announcements on handwashing, the comprehension of this announcements, the intention of behavioral change and the practice of handwashing. Results: In particular, the proportion of exposure is more women and highly educated. The comprehension of the announcement was no statistically significant difference. The intention of behavior change showed higher in workers and understanding of the announcements. The practice of handwashing is higher in women and lower in student/unemployed. There was no difference in practice in accordance with the exposure, the comprehension and the intention of behavioral change. Conclusions: About the comprehension of the announcements and the intention of behavioral change, the effects of the public service announcements on handwashing can be very positive. But it does not affect the actual practice of hand washing. The handwashing promotion programs will have to devise a strategy and structure, operation method considering realistic and scalable platform.

• 전자공학회논문지
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• 제50권9호
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• pp.127-135
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• 2013

저조도 환경에서 카메라로 영상을 획득하기 위해 일반적으로 가시광 플래시를 사용하거나 장노출 기법을 사용하게 된다. 그러나 가시광 플래시를 사용할 때 플래시 광에 의한 색 왜곡이나 적목 현상, 눈부심에 의한 거부감을 발생시킨다. 또한 장노출을 사용하게 되면 물체의 움직임에 의한 흔들림 현상이 발생하게 된다. 따라서 최근에는 이러한 단점을 극복하고, 저조도 환경에서 고화질의 영상을 획득하기 위하여 멀티 스팩트럴 플래시(Multi-spectral flash image)를 이용하여 영상을 획득하는 방법이 소개되었다. 이 방법은 가시광과 UV/IR스펙트럼의 다섯 채널을 이용하여 가시광영상의 색 정보와 UV/IR 스팩트럼 영상의 세부정보를 최적화하여 영상을 획득하는 방법이다. 하지만, 픽셀 기반의 최적화 과정에 있어 색 왜곡과 다른 잡음을 발생시키게 된다. 따라서 본 논문에서는 이러한 색 왜곡과 잡음을 개선하기 위해 영역 기반의 가중치 맵을 최적화 방법에 적용하여 색 왜곡을 개선하는 알고리즘을 제안한다. 먼저, 영상에 대하여 Canny 에지 검출 방법을 사용하여 영상의 윤곽을 검출하였다. 이를 가중치 맵으로 최적화방법에 적용함으로, 세부 영역에 대하여 UV/IR 플래시 영상의 정보에 가중치를 부여하고, 평탄한 영역에 대하여 가시광 영상의 색 정보를 가중치를 부여하여 색 왜곡을 개선하였다. 제안한 방법을 평가하기 위하여 실험을 통하여 제안한 방법과 이전방법을 비교하였고, 객관적 평가와 주관적 평가 모두 제안한 방법이 우수한 성능을 나타내었다.

• Journal of Preventive Medicine and Public Health
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• 제28권4호
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• pp.765-771
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• 1995

치과용 핸드피스에서 발산하는 고주파수의 진동에 의한 일시적 진동감각역치 변화를 관찰하고자 치과위생병 28명을 대상으로 34,000rpm의 low-speed handpiece를 진동기구로 사용하였다. 진동에 폭로시키기 전과 후, 치과의사가 스케일링시 취하는 작업자세에 5분간 폭로시킨 후의 진동감각역치를 청력계기의 골전도진동기를 사용하여 250 Hz에서 그들이 주로 사용하는 손의 제2지두수에서 측정한 결과, 각각 $23.5{\pm}3.5dB,\;30.8{\pm}4.2dB,\;23.7{\pm}4.6dB$로 진동에 5분간 폭로시킨 후의 역치가 폭로 전에 비해 7.3dB의 유의한 증가가 있었다(p<0.001). 진동폭로 전후의 차이에 따른 분포를 보면, 10 dB 내외로 증가한 사람이 71.4%로 대부분이었고 16 dB의 증가가 가장 높았다. 진동 폭로 전의 진동감각역치와 신장, 체중, 체질량 지수와의 상관관계는 각각의 상관계수가 0.0360, -0.1657, -0.2641로 통계적 유의성은 없었으며, 흡연에 따른 차이도 흡연군(N=20)과 비흡연군(N=8)의 진동감 각역치가 각각 23.1 dB, 24.6 dB로 그 차이 가 없었다. 본 연구 결과로 볼 때 핸드피스와 같은 고주파-진동기구를 사용하는 치과의사 및 치과위생사에게서 진동감각역치의 변화가 예상되며, 말초신경병증의 원인이 될 수 있는 작업자세에 의한 장기간의 영향 및 아말감 충전시 사용하는 수은의 영향에 대해서도 연구가 필요할 것으로 생각된다.

• 한국산업보건학회지
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• 제10권1호
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• pp.45-57
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• 2000

Results of environmental monitoring for 35 steel industry welders exposed to manganese and chromium fume were evaluated. Efficiency of respiratory protectors, welding face shields and local exhaust ventilation were also evaluated to establish more efficient preventive measures that can protect welders from occupational disease as related to welding fume. The results are as follows; 1. Total fume from $CO_2$ arc welding with mild steel occurred 1.5 to 2.2 times more than that from shielded metal arc welding. Chromium and nickel fume from welding with stainless steel occurred 27 to 59 times and 18 to 30 times, respectively, than those with mild steel. 2. Proportions of water-soluble chromium(VI) and insoluble chromium(VI) Compare to total chromium occurring from $CO_2$ arc welding with stainless steel were 10.5% and 8.7%, respectively, while those with mild steel were 57.1 to 63.2% and 31.6 to 38.1%, respectively. 3. The efficiencies of 4 types of respiratory protectors to reduce welding fume exposure were evaluated as 54.4 to 64.4%. 4. The reducing effect of head type welding face shield was 67.6%, and that of hand type welding face shield was 58.5%. The highest reducing effect was shown in air supply welding face shield as 99.2%, although it is not convenient to wear. 5. When welding face shield and respiratory protectors were worn together, the reducing efficiency increased to 79.0 to 87.5%. 6. When local exhaust ventilation was installed in workplace, the reducing efficiencies varied from 31.5 to 73.1% according to the types of welding.

• Environmental Analysis Health and Toxicology
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• 제22권1호
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• pp.19-26
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• 2007

Accumulation of tributyltin (TBT) in serum, liver and muscle of olive flounder (Paralichtys olivaceus) was investigated in a 60-d static renewal exposure at $0.1{\mu}g$ TBT/L. Tributyltin accumulated rapidly from 83 ng Sn/g to 2,227 ng Sn/g on a wet weight basis in the serum of the olive flounder and to a greater extent than in the other tissues. The accumulated TBT concentrations in tissues were in the order of serum>liver>muscle on wet or dry-weight basis. High concentrations of dibutyltin (DBT: 990 ng Sn/g dry wt) and monobutyltin (MBT: 141 ng Sn/g dry wt), degradation products of TBT were found in liver of olive flounder at the end of exposure. On the other hand, DBT and MBT was below the detection limits in muscle during the exposure, and only low concentration of DBT (56 ng Sn/g) were detectefd in serum. Butyltin compounds were also quantitatively determined in feral fine-spotted flounder (Pleuronichthys cornutus) collected from Gwangyang Bay as one of polluted area and Sori Island as a reference site. All three butyltin compounds were detected from the fine-spotted flounder from Gwangyang Bay up to 3,107 ng Sn/g of total butyltins in liver, while 120 ng Sn/g of total butyltin concentration was found in the liver of fish from Sori Island.