• 정보학연구
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• 제8권1호
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• pp.113-118
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• 2005

Investigation of surface discharge characteristics of surface leakage on polluted EPDM insulator have been performed. This work was performed utilizing High Frequency Current Trans former to monitor surface discharge. It was found that there were significant variation in the surface discharge waveform frequency spectrum, depending both on the surface discharge magnitude and more importantly on the duration of surface discharge activity.

• Journal of Radiation Protection and Research
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• 제38권4호
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• pp.242-245
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• 2013

원전 방사선작업종사자의 내부선량평가를 위해 일반적으로 사용되고 있는 bed type 전신계측에 몬테카를로 방법을 적용하여 작업자에 대한 외부오염 계측특성을 평가하였다. 한국인 체형을 반영하는 voxel 모의 피폭체를 이용하여 내부오염시 측정 특성을 평가하였다. 외부오염 판별을 위해 BOMAB 모의 피폭체를 이용하여 신체 각 부위별 오염시 나타나는 측정 특성을 평가하였다. 가슴 부위 오염시 누운 자세와 엎드린 자세로 구분하여 외부오염시 계측 특성을 확인하였다. 정량적인 분석을 통해 bed type 전신계측기를 이용한 외부오염 판별이 가능함을 확인하였다.

• 한국산업보건학회지
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• 제33권4호
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• pp.395-402
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• 2023

Objectives: Microbial contamination of face masks used by healthcare professionals can vary depending on the degree of exposure to bioaerosols in various healthcare environments. However, research on this topic is limited. Therefore, we analyzed microbial contamination of N95 respirators used in hospital offices, wards, and outpatient settings. Methods: Samples isolated from N95 respirators worn for 2, 4, and 6 hours were incubated at a temperature of 35-37℃ or 25-28℃ for 24 hours or for 3-7 days, and colony-forming units were counted in chocolate agar, tryptic soy agar, and Sabouraud dextrose agar plates. Total indoor airborne bacteria were also measured in the healthcare environments. Finally, microbial species were identified using Gram staining with a microscopic speculum. Results: The three types of environments did not deviate from the maintenance of standard indoor air quality. There was no difference between the microbial species identified in the healthcare environment and mask contamination. However, the number of bacteria in the masks worn in each environment differed, and the degree of contamination increased with mask-wearing time (p<0.05). Conclusions: Therefore, care must be taken to avoid recontamination of masks due to improper use and exposure to biological hazards in healthcare environments. In conclusion, scientific evidence is necessary for safe mask-wearing times. Based on the results of this study, we hope to conduct further research to establish guidelines for the safe use of face masks during respiratory disease epidemics.

• 한국자동차공학회논문집
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• 제24권6호
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• pp.627-634
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• 2016

In this paper, an augmented video generation method to evaluate the performance of lane departure warning system is proposed. In our system, the input is a video which have road scene with general clean lane, and the content of output video is the same but the lane is synthesized with contamination image. In order to synthesize the contamination lane image, two approaches were used. One is example-based image synthesis, and the other is background-based image synthesis. Example-based image synthesis is generated in the assumption of the situation that contamination is applied to the lane, and background-based image synthesis is for the situation that the lane is erased due to aging. In this paper, a new contamination pattern generation method using Gaussian function is also proposed in order to produce contamination with various shape and size. The contamination lane video can be generated by shifting synthesized image as lane movement amount obtained empirically. Our experiment showed that the similarity between the generated contamination lane image and real lane image is over 90 %. Futhermore, we can verify the reliability of the video generated from the proposed method through the analysis of the change of lane recognition rate. In other words, the recognition rate based on the video generated from the proposed method is very similar to that of the real contamination lane video.

• 한국생산제조학회지
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• 제21권4호
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• pp.541-546
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• 2012

This study investigates the detection system of oil pollution level using single optical fiber sensor. This study focus on sensing of oil pollution by moisture and iron powder which are representatives of oil pollution factor. In addition, It is placed that the water and iron powder as an oil pollution factor in the oil tank which is the oil circulation in. The oil pollution detection system was measured by the changing of intensity of light and sensing gap. The result of this experimentation not only confirmed the contamination by moisture volume in the oil tank from the section 190ppm to 540ppm, but also monitored the contamination by iron volume from the section 1200ppm to 3500ppm. This study confirmed effectiveness of this detection system using optical fiber sensor. There is expectations of measuring another section by various optical fiber sensor.

• 응용통계연구
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• 제17권3호
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• pp.475-488
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• 2004

위치추정량에서 로버스트한 추정기법 중의 하나로 알려진 데이터 뎁스(depth)를 회귀추정에 적용한 회귀뎁스(regression depth)는 Rousseeuw and Hubert(1999)에 의하여 제안되었다. 이 이외의 회귀뎁스 추정량으로는 심플리셜(simplicial) 뎁스와 사영(projection) 개념의 뎁스 회귀추정량들이 있다. 본 논문에서는 뎁스 기반 회귀추정량들의 성능에 대한 모의실험을 여러 오염 조건에서 행하여 비교하였으며 기존의 우수한 로버스트성을 지니는 추정량으로 최근에 제안된 HBR추정량(Chang et al., 1999)들과의 비교연구도 하였다. 2차원 공간에서의 실험은 전반적으로 사영뎁스기반 회귀추정량이 좋은 결과를 보여주었다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제8권1호
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• pp.57-67
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• 2003

지하수 의존도가 큰 농촌지역에서 주로 사용하는 천부지하수는 오염에 민감하므로, 인간활동에 의한 질산성 질소 오염이 생활용수 공급에 큰 문제가 되고 있다. 농경활동과 함께 다양한 규모의 축사가 운영되고 있는 경기도 일죽지역 천부지하수에 대한 질산염 연구결과, 인위적 오염물질 유입이 예상되는 지점이 77%, 먹는물 수질기준을 초과하는 지점이 32～42%로 나타났다. 질소동위원소 분석 결과, 인위적 오염물질 유입이 예상되는 지점은 모두 $\delta^{15}$N-$NO_3$가 5$\textperthousand$ 이상으로 나타났으며, 59%지점이 동물분뇨에서 유래된 질소의 영향을 강하게 받고 있는 것으로 나타났다. 연구지역 천부지하수의 질산성 질소 주 오염 원인은 밀집된 축사로 밝혀졌으며, 운영이 종료된 축사라도 오랫동안 지하수질에 영향을 미치는 것으로 보인다. 축종에 따라 오염원의 화학적 특성이 다른데, 지표수게는 그 영향이 나타나지만, 지하로 유입되는 동안 반응에 의하여 일부 용질이 제거되므로 지하수에서는 오염원 차이에 의한 영향이 나타나지 않았다.

• 환경위생공학
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• 제8권2호
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• pp.99-108
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• 1993

It is well known that we should take 2L of drinking water per day to maintain our health. The drinking water quality is becoming worse owing to sewage discharge and industrial wastewater. Surface water is polluted by various kinds of contaminants and ground water were known as clean and unpolluted water, but through recent many reports the ground waters are also contaminated by waste disposal and intrusion of organic and bacterial movement. This research was undertaken to make a water index of water contamination by referringcations cations and anions. NH$_{4}$, Fe, Mn, and Pb are chosen as cations and $NO_3$, Cl, and $SO_4$ ions are chosen as anions to make a index, and the following water index was made as the contamination index. (Fe+Mn+Pb)/0.7+$(NH_4+NO_3+Cl+SO_4)$/10.5<6.0 By using ton Chromatography the cations and anions are rapidly analyzed and plotting the analyzed data to the equation, we can easily get the degree of contaminations by avoiding analysis of over 37 water parameters in several days. Of course this index of water contamination is not perfect and detail one, but in case of emergent case or to know the overall trends of contamination, it is convenient to use this index. Among the tested 5 kinds of samples the ground water showed contamination index of 6.87. Authors used the already published healthy index and tasty index and differentiated their degrees in detail.

• 대한간호학회지
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• 제14권2호
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• pp.55-62
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• 1984

This study was performed from september 26th to October 7th 1981 to investigate the contamination problems of Nurse's hands characterized by var-ious nursing functions. A total of 50 nurse's hands were sampled from 5 different wards of H. University Hospital. The samples were cultured for isolation of microorganisms. The results were as follows: 1. Of 50 Nurses 23 were found to be contaminated by 9 species of bacilli such as Non-fermentative gram negative Bacilli, Gram negative bacilli, Oxidase positive, Enterobacter, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter, Staphylococcus epidermidis, Gaffkya tetragens, Bacillus subtilis. 2. The contaminate rates by wards where they have been serving are; 7 (87.5％) of 8 nurses from Intensive care unit, 7(70%) of 10 nurses from general surgery ward, 3(50%) of 6 nurses from neurosurgery ward, 2(20%) of 10 nurses from orthopedic surgery ward, 4(25%) of 10 nurses from medical ward. 3. The contamination rates by the types of clinical service offered are 6(85.7%) of 7 nurses after wound dressing assist 6 (55.3%) of 13 nurses after vital sign check. 4. No statistical significance could he observed as to the between the rates of contamination of nurse's hands with various nursing functions (0.1

• Journal of Radiation Protection and Research
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• 제41권2호
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• pp.133-140
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• 2016

Backgrounds: The accident at Fukushima Daiichi Nuclear Power Plant (NPP), March 2011, caused serious radioactive contamination over wide area in east Japan. Therefore, it is important to know the effect of the accident and the status of NPP. Materials and Methods: This paper provides a review on the status of radiation dose and radioactive contamination caused by the accident on the basis of publicized information. Results and Discussion: Monitoring of radiation dose and exposure dose of residents has been conducted extensively by the governments and various organizations. The effective dose of general residents due to the accident proved to be less than a mSv both for external and internal dose. The equivalent committed dose of thyroid was evaluated to be a few mSv in mean value and less than 50 mSv even for children. Monitoring of radioactivity concentration has been carried out on food ingredients, milk and tap water, and actual meal. These studies indicated the percentage of foods above the regulation standard was over 10% in 2011 but decreasing steadily with time. The internal dose due to foods proved to be tens of ${\mu}Sv$ and much less than that due to natural $^{40}K$ even in the Fukushima area and decreasing steadily, although high level concentration is still observed in wild plants, wild mushrooms, animals and some kind of fishes. Conclusion: According to extensive studies, not only the effect of the accident but also the pathway and countermeasures against radioactive contamination have been revealed, and they are applied very effectively for restoration of environment and reconstruction of the area.