• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.04a
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• pp.262-266
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• 2011

본 연구에서는 건축물 내장 재료에 대한 연소독성평가와 독성지수연구로써 FT-IR을 이용한 연소가스분석실험을 하였다. 독성지수를 산정하기 위한 실험의 화재모델로 콘 칼로리미터 화재모델(KS F ISO/TR 9122-4)을 사용하였으며 ISO 19702의 절차에 따라 FT-IR을 이용하여 건축 재료의 연소로부터 발생되는 가스의 분석을 수행하였다. 국제규격에서 제시하고 있는 몇 가지 독성지수 산정법 중 ISO 13344에서 규정하는 방법에 따라 FED 값을 산정하였으며, 30분간 시험동물에 노출 시 대상의 50%가 사망하는 농도인 $LC_{50}$을 기준으로 하여 3가지 재료의 독성지수화를 통해 상대적인 독성 위험도를 평가하였다.

• Journal of radiological science and technology
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• v.44 no.6
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• pp.599-605
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• 2021

The International Electrotechnical Commission (IEC) 62494-1 has defined the exposure index (EI) that have a proportional relationship with the dose incident on the image receptor, and target exposure index (EI_T), deviation index (DI). In this study, an appropriate EI_T for skull radiography was established through the diagnostic reference level (DRL) and changes in DI were confirmed. Entrance surface dose (ESD) and EI were obtained using the computed radiography system displayed the EI as per IEC on console and skull phantom by experiment based on the national average exposure conditions announced in 2012 and 2019. And appropriate EI_T was established by applying the DRL in 2012 and 2019. As a results, the EI_T is changed according to the change in the DRL, and the exposure condition that becomes the ideal DI according to the change in the EI_T also has a difference of about 1.41 times. DRL is recommended to optimize the patient dose, however it is difficult to measure in real time at medical institutions whereas EI and DI are displayed on the console at the same time as exposure. When the EI_T is set based on the DRL and the DI is closed to an ideal value, it is useful as a patient dose management tool. Therefore, when the EI_T is periodically managed along with the revision of the DRLs, the patient dose can be optimized through the EI, EI_T and DI.

• Journal of Radiation Protection and Research
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• v.38 no.1
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• pp.29-36
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• 2013

The aim of this study was to determine the correlation between exposure index (EI) and dose factors related to radiation dose optimization in digital radiography (DR) system. Two phantoms with built-in regional test object for quantitative assessment of images were used to produce image signals that acquired in chest radiography background. EI and entrane surface dose (ESD) increased proportionally with rise of radiation dose (kVp, mAs) in both DR and CR systems. Especially, DR detector was effective to form good contrast and hence, reached easily to improvement of image quality with minimal dose changes. It made operators possible to expect the accuracy of EI values deeply related to absorbed dose of the detector. The evaluation of images was obtained specially employed calculation of noise to signal ratio (NSR) and contrast to noise ratio (CNR). These measurements were performed for how exposure factors affect image quality. NSR was inversely proportional to kVp and mAs and low NSR represented high signal detection efficiency. Consequently, EI values was the measure of the amount of exposure received by the image receptor and it was proportional to exposure factors. Therefore the EI in a recommended range from manufacturer can offer optimal image quality. Also, continuous monitoring of EI values in the digital radiography can reduce the unnecessary patient dose and help the quality control of the system.

• Journal of the Korea institute for structural maintenance and inspection
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• v.1 no.2
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• pp.131-140
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• 1997

콘크리트 교량을 저렴하고 신속하게 상태 평가를 하기 위하여 성능 지수(Performance Index)를 제안한다. 이 기법은 육안 검사에 의하여 발견된 결함의 범위와 심각도를 사용하여 콘크리트 교량의 전반적인 상태를 신속하게 등급화 하고 콘크리트 교량의 노출 조건을 고려하여 콘크리트 성능을 정량적으로 평가한다. 또한 본 연구에서는 상기한 성능 지수 기법의 타당성을 증명할 수 있는 정밀 안전 진단 시험결과를 활용하여 6개의 주요 노후화 원인을 고려하는 또 다른 성능 지수를 제안한다. 이러한 두 상태 평가 방법이 영국의 실제 교량 상태 평가 자료를 바탕으로 한 상태 평가 결과를 퍼지 집합 이론(fuzzy set theory)으로 분석한 결과와 비교하여 방법의 정당성 및 신뢰성을 논의한다.

• Journal of agricultural medicine and community health
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• v.29 no.2
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• pp.265-285
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• 2004

Objectives: The acute toxic effects of pesticide are well known. Concern has also been expressed that long-term exposure may result in damage to the central nervous system. This study was conducted to test the hypothesis that central nervous system symptoms might occur due to pesticide exposure. Methods: In a cross-sectional study, first, cumulative exposure index (CEI) was estimated. Neurologic symptoms (Q-16 questionnaire) for 541 farmers (exposed to pesticides) were compared with 119 non-exposed persons in spraying season nine rural areas in Korea. Results: The pesticides poisoning rates for last 3 months were 67.2% for orchard farmers, 55.3%for dry field farmers, and 20.5% for husbandry farmers, respectively, showing significant difference (p<0.001). Compared with non-exposure group, exposure groups (especially, orchard farmers) reported significantly more neurologic symptoms and had a higher overall neurological symptoms score (p<0.001). Factors related to the positive neurological symptoms (answers "yes" to six or more of Q-16 questionnaire) adjusted for age, sex, education level, smoking and alcohol drinking were type of farming (OR 3.08, 95% CI 1.50-6.30 in orchard farmers vs non-exposure group), CEI (OR 2.75, 95% CI 1.12-6.78 in Q3 vs Q1), past poisoning (OR 1.97, 95% CI 1.21-3.20 vs normal), current mild poisoning (OR 3.03, 9500 CI 1.47-6.22 vs normal) and current moderate poisoning (OR 6.34, 95% CI 3.03-13.25 vs normal), respectively. Conclusions: These results suggest that long-term exposure to pesticides appears to be associated with subtle changes in the central nervous system.

• The Korean Journal of Pesticide Science
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• v.16 no.1
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• pp.69-77
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• 2012

To evaluate the effect of endocrine disruption chemicals (EDCs) to aquatic organisms, muddy loach (Misgurnus anguillicaudatus) was exposed to low concentration methomyl for 21 days in order to identify the effect of biomarkers and endocrine. Vitellogenin (VTG) in blood plasma, which used widely as validated biomarker for endocrine disruption, was significantly greater in male fish exposed to 0.4 mg/L and 2 mg/L methomyl, and in female fish exposed to 0.08 mg/L, 0.4 mg/L, and 2 mg/L methomyl for 21 days (p<0.05). This results suggest that methomyl have probability of endocrine disruption to organism on aquatic system. While inhibition of Acetylcholinesterase (AChE) activity and increase of DNA damage in comet assay were verified by fish exposed to methomyl, change of ethoxyresorufin-O-deethylase (EROD) activity was not occurred, comparing the control group (p<0.05). Indicators at the level of organism such as condition factor (CF), hepato-somatic index (HSI), and gonado-somatic index (GSI) were not influenced by exposure of methomyl. In conclusion, these results showed the possibility of methomyl in regard to not only endocrine disruption but also impacts on biochemical biomarkers to aquatic organisms.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.2
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• pp.257-267
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• 2004

Our study investigated the association between solvent exposure and acquired color vision loss using the Lanthony D-15 desaturated panel in petrochemical industry. Since neurotoxic effects associated with chronic solvent exposure, subjects with more than 6 months of exposure were included. Exposure assesment was estimated mean, maximum and cumulative 8hr TWA from individual 8-hour sampling. Exposure status were classified into two groups, occupationally exposed group to solvent and a non-exposed group. The results showed that CCI was positively related for age. According to the results of qualitative analysis, there was no significant difference in the prevalence of specific Type of dyschromatopsia the two examined group. However, the prevalence showed a higher proportion of dyschromatopsia to solvent exposure. It was affect with acquired dyschromatopsia(Type II, III and Complex) in exposed worker group(5.9%,7.86%,14.99%, respectively) than in the nonexposed group(6.16%,7.55%,13.71%, respectively). After each variable was adjusted for age, alcohol and tobacco consumption, a relationship between acquired dyschromatopsia and exposure showed an increase in the Odds ratio as compared to the nonexposed group at only left. The results showed that acquired dyschromatopsia was positively related to age (p<0.001). The results showed that solvent exposure, although not significant, could cause the acquired dyschromatopsia and visual system can serve important information on early neurotoxic effects in generally. Therefore, we need to concerns about eye health in workers.

• Journal of Korea Society of Industrial Information Systems
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• v.9 no.2
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• pp.1-8
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• 2004

In this paper, we propose three estimators of Kullback-Leibler Information functions using the data from accelerated life tests. This acceleration model is assumed to be a cumulative exposure model. Some asymptotic properties of proposed estimators are proved. Simulations are performed for comparing the small sample properties of the proposed estimators under use condition of accelerated life test.

• Environmental Analysis Health and Toxicology
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• v.23 no.3
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• pp.171-178
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• 2008

수백여 종의 개별물질이 불완전 연소 혹은 유기물의 열분해로 인해 발생되는 다환방향족 탄화수소(PAHs)는 환경에서 중요한 오염원이 되고 있다. 본 연구는 다양한 바이오마커를 이용하여 수서생태계에 벤조피렌(benzo[a]pyrene)과 같은 다환방향족 탄화수소의 영향을 분석하였고, 이에 대한 통합적 결과 모델을 도출하였다. 즉, 잉어(Cyprinus carpio)를 이용하여 여러 농도의 벤조피렌(3, 12, $34{\mu}g/L$, 측정농도 기준)에 10일간 노출시킨 다음, DNA single-strand break, ethoxyresorufin-O-deethylase (EROD), acetylcholine esterase (AChE)와 vitellogenin (VTG)의 농도를 측정하였다. 벤조피렌은 잉어의 DNA 손상을 유도하였고, 낮은 농도에서 EROD와 VTC의 유의적인 활성을 보였으나, 신경전달물질과 관련이 깊은 AChE 효소활성에는 영향을 미치지 않았다. 이 결과를 star plot를 이용하여 통합 및 분석하였으며, 노출농도에 따른 통합 반응지수(integrated biomarker response value: IBR)로 나타내었다. 이런 다양한 바이오마커의 결과들은 벤조피렌에 대한 어류의 영향과 수생태 모니터링 자료로 이용 가능할 것으로 여겨지며, 통합반응지수는 생태위해성평가에서 유용한 도구로 쓰일 가치가 있는 것으로 평가된다.

• Journal of the Korean Society of Radiology
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• v.11 no.6
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• pp.459-466
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• 2017

The purpose of this study was to evaluate the difference of dose and image quality according to the material of the additional filter plate by selecting copper and nickel. First, the absorbed dose was measured using a Rando phantom setting the additional filter plates of copper and nickel None, 0.1 mm, 0.2 mm, and 0.3 mm under 120 kVp, and 6.3 mAs. Second, We acquired image according to filter thickness of copper and nickel. by changing the tube voltage of 90 kVp, 100 kVp, 110 kVp, 120 kVp and exposure indexes of 400, 800 and 1600. Third, we obtained the SNR and CNR values using the Image J program and evaluated quantitatively and then evaluated image quality. As a result, Absorbed dose measurements showed that nickel was higher than copper, and the absorbed dose decreased as the thickness increased(p<0.05). Furthermore, Quantitative analysis of images showed no significant difference between the two images according to change the voltage and the exposure index(p>0.05). In conclusion, this study confirms that the nickel addition plate can maintain the current image quality while reducing the exposure dose compared to copper.