• 한국산업보건학회지
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• 제11권3호
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• pp.190-197
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• 2001

Noise-induced hearing loss(NIHL) was the highest rate (43.5%~58.5% from 1996 to 1998) of positive findings through specific medical program in Korea. There were much more NIHL at workers of automobile manufacturing factories than other manufacturing factories. The specific aim of the present study was to determine the noise exposure of automobile press lines, according to their job titles, press line types(auto, semiauto), dosimeter parameters setting. There were a total 11 press lines sampled at a automobile manufacturing company. Among those press lines, 10 press lines were autolines with acoustic enclosure, one semiauto press line was no aucostic enclosure Noise exposure data were sampled for an work shift using noise dosimeter, which recorded both time-weighted average(TWA) and 1-min average. The mean OSHA TWA(Korea TWA with threshold 90) was $80.7dB(A){\pm}4.7dB(A)$ for leader, $82.8dB(A{\pm}4.5dB(A)$ for pallette man, $76.7dB(A){\pm}4.3dB(A)$ for press operators, $76.6dB(A){\pm}5.6dB(A)$ for crane operators, $77.1dB(A){\pm}2.8dB(A)$ for forklift drivers, whereas the mean NIOSH TWA was $88.9dB(A){\pm}1.7dB(A)$ for leader, $89.6dB(A){\pm}2.1dB(A)$ for pallette man, $86.7dB(A){\pm}1.8dB(A)$ for press operators, $88.5dB(A){\pm}2.0dB(A)$ for crane operators, $87.7dB(A){\pm}1.0dB(A)$ for forklift drivers. While L10 for NIOSH TWA samples was 84.8 dB(A) ~ 87.3 dB(A), L10 for OSHA TWA samples was 69.5 dB(A) ~ 77.4 dB(A). L10 means that the TWA for 90% of the samples exceeded L10. Among OSHA TWA(Korea TWA with threshold 90) samples for pallette man, 7.7 % exceeded 90 dB(A), the OSHA permissible exposure level, but OSHA TWA samples for the other job titles didn't. Among NIOSH TWA samples, the samples over 85 dB(A), the NIOSH recommended exposure limit, was 100% (leaders), 83.3 %(operators), 97.4%(palletteman), 100%(forklift drivers), 91.7 %(crane operator). The results of One-way random effects analysis of variance models shows that the difference between job titles was significant by OSHA TWA(p<0.05), but not significant by NIOSH TWA(p>0.05). NIOSH TWA samples were significantly higher than OSHA TWA samples(P<0.05). Regression analysis was used to obtain relationships between OSHA TWA samples and NIOSH TWA samples. In this case the coefficient of determination = 0.90, which shows the high degree association between two methods. Regression equation, NIOSH TWA = 0.552 * OSHA TWA + 42.13 dB(A), shows that if OSHA TWA is known, NIOSH TWA can be predicted by the equation. The mean TWA difference between threshold 80 dBA and 90 dBA was significant(p<0.01). While the TWA noise exposures were 7.7% above the Korea(OSHA) PEL, they were more than 83.3% over NIOSH REL. Automobile workers were exposed to noise level that could be potentially damaging to their hearing. It found that there is approximately 25% excess risk of hearing loss even if a worker is protected to the PEL in according to NIOSH study.

• 대한전자공학회논문지SD
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• 제43권7호
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• pp.20-28
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• 2006

본 논문에서는 불규칙하고 복잡한 다층(multi-layer) RLC 배선에 대하여 TWA(Traveling-wave-based Waveform Approximation)을 기반으로 한 새로운 시그널 인테그러티 검증에 대한 방법을 제시한다. 실제 레이아웃 구조의 불규칙한 배선을 가상 직선 배선으로 변환하고 이를 TWA 기법을 사용하여 효율적으로 검증하였다. 여기서 제안된 방법은 3차원 구조에 대한 회로 모델을 사용한 일반적인 SPICE 시뮬레이션에 비하여 계산시간을 현저하게 단축시킬 수 있으며, 타이밍의 경우 5% 이내에서, 크로스톡의 경우 10% 이내에서 정확하다는 것을 보인다.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제1권1호
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• pp.1-6
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• 2012

템플릿 기반 웹 애플리케이션(TWA)은 웹 페이지들의 공통부분을 단일 코드 파일(템플릿)로, 각 페이지에 특화된 부분은 별도의 파일로 관리한다. HTTP 요청이 발생하면 이 두 종류 파일을 동적으로 조합하여 웹 페이지를 생성한다. 이를 통해 사용자에게 일관된 UI을 제공하며 코드 중복을 제거해 유지보수성을 향상시킨다. 그러나 TWA는 사용자의 요청 시 현재 페이지에서 바뀌어야 할 부분이 일부지만 페이지 전환이 이루어져 갱신이 불필요한 데이터까지 전송되고 처리되는 문제가 있다. 본 논문은 Java 기반 TWA를 대상으로 이 문제를 해결한다. 제안 기법은 페이지 전환을 제거하기 위해 HTML에 있는 하이퍼링크를 AJAX를 이용하는 JavaScript 이벤트 핸들러로 변환한다. 또한 갱신에 필요한 데이터만 반환하기 위해 JSP, Servlet 코드에서 템플릿 전송 코드를 제거한다. 따라서 이 기법은 페이지 전환으로 발생하는 네트워크와 CPU 부하를 감소시키며, 비동기적인 페이지 업데이트로 사용자의 체감 성능을 향상시킨다. 성능 검증을 위해 전형적인 TWA를 대상으로 이 기법을 적용하였다. 성능 측정 결과 기존 TWA보다 응답시간을 최대 87% 개선하였다.

• 대한음성언어의학회:학술대회논문집
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• 대한음성언어의학회 2003년도 제19회 학술대회
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• pp.148-148
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• 2003

목적 : 베르니케실어증환자의 치료에 있어서 전통적 기법은 청각적 이해력을 높이기 위해 청각변별력을 직접적으로 치료한다. 그에 반해 Helm-estabrooks 등(1991)에 의해 개발된 TWA(Treatment for Wernicke's Aphasia)는 읽고 이해하기(reading comprehension), 구두읽기(oral reading), 따라 말하기(repetition)등의 과정을 통해 재청각화(reauditorization)를 유발하여 청각이해력(auditory comprehension)을 향상시키는 언어치료 프로그램이다. 본 연구자들은 TWA가 베르니케실어증을 가진 한국인의 재청각화에도 효과적인지를 알아보고자 하였다. (중략)

• 월간산업보건
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• 통권273호
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• pp.40-43
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• 2011

Perchloromethyl mercaptan에 대한 직업적 노출기준으로 TLV-TWA 0.1 ppm(0.76 mg/$m^3$)으로 권고한다. TLV-TWA 0.1 ppm(0.76 mg/$m^3$) 은 눈과 코의 자극 그리고 불쾌한 냄새로 인한 불편함의 가능성을 최소화하는 수준이다. Perchloromethyl mercaptan에 대한 동물 노출 실험연구와 근로자들의 노출연구 자료는 매우 제한적이다. 사고로 확인되지 않은 농도에 근로자들이 노출된 경우, 발견된 증상과 징후는 눈, 목, 가슴에 심한 자극과 기침, 눈물, 호흡곤란, 메스꺼움, 구토, 빈맥, 청색증, 경련 그리고 폐부종에 의한 사망이다. Perchloromethyl mercaptan을 활용하는 생산설비에서 TLV-TWA 0.1 ppm 이하 농도의 증기에 노출되었을 때 질병을 유발하였다는 보고는 없었다. 피부흡수, 발암성 그리고 TLV-STEL을 권고하기 위한 유용한 자료는 충분하지 않다.

• 한국산업보건학회지
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• 제33권1호
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• pp.3-5
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• 2023

Objective: This study introduces exposure concentrations of time-weighted average standard (TWA) evaluation and short-time exposure standard (STEL) evaluation for trichloroethylene in the cleaning process. Methods: Trichloroethylene measurement was conducted according to the KOSHA Guide (A-24-2019) method. It was carried out twice. Results: As a result of the first measurement, TWA concentration exceeded 4 times the exposure standard and STEL concentration exceeded 16 times, but the inaccuracy and breakthrough of the collection time could not be considered, so the second measurement was conducted. The second measurement result was lower than the first measurement result, but exceeded the exposure standards (TWA, STEL). Conclusions: We were able to confirm that the exposure level of workers in the cleaning process using trichloroethylene exceeded the exposure standard. And it is also considered necessary to grasp the approximate concentration using a detector tube in the preliminary survey.

• 월간산업보건
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• 통권295호
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• pp.11-14
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• 2012

Phenothiazine의 직업적 노출기준(TLV-TWA)은 $5mg/m^3$으로 권고되었다. TLV-TWA의 수준은 피부자극과 변색, 각막염 그리고 태양광에 직접 노출되었을 때 나타나는 광감작반응의 가능성을 최소화하기 위해 설정되었다. 고용량의 phenothiazine을 경구 투여하면 간과 신장이 손상되며 용혈성의 빈혈이 발생한다. Phenothiazine의 피부흡수에 의한 전신 독성이 증명되어 피부흡수 "Skin" 경고주석을 권고하였다. 감작제(SEN)와 발암성 경고주석 그리고 TLV-STEL을 설정하기에는 유용한 자료가 부족하다.

• 항공우주시스템공학회지
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• 제6권1호
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• pp.7-12
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• 2012

Fuel tank design requires special care because tank explosion can cause catastrophic event with high possibility as shown in accident of TWA 800. In this study, cause of fuel tank explosion was reviewed and several design considerations to minimize explosion possibility were introduced.

• 한국산업보건학회지
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• 제8권1호
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• pp.95-104
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• 1998

This Study was conducted at nine Histological Laboratories in the hospitals located in Seoul from August 20 to October 10, 1996. The main purpose of this study was to assess the TWA & STEL exposure to formaldehyde and to evaluate factors affecting formaldehyde concentration in Histological Laboratory. With evaluated factors, proper improvement strategy to minimize exposure was suggested. The results are summarized as follows ; 1. The TWA concentrations of the personal samples ranged from 0.02 to 3.86 ppm and that of one laboratory out of nine was exceeding 0.75 ppm, USA OSHA standard. The TWA concentrations of the area samples ranged from 0.08 ppm to 1.49 ppm and those of three laboratories out of nine were exceeding OSHA standard. 2. When measurement was conducted on the working tables. around Formaldehyde vessel, fixation container and storage cabinet, the geometric means of TWA concentrations were 0.62 ppm, 0.64 ppm. 0.58 ppm and 0.37 ppm respectively. 3. When overnight fixed specimens were examined, the STEL concentrations of personal samples ranged from 0.59 ppm to 5.01 ppm, those of three laboratories out of nine were exceeding 2 ppm, OSHA standard and the STEL concentrations of area samples ranged from 0.31 ppm to 3.08 ppm, those of four laboratories from nine were exceeding OSHA standard. 4. Factors affecting Formaldehyde exposure level were sanitation state of laboratory, volume of the room and opening state of fixation container & formaldehyde vessel(p<0.05).

• 한국산업보건학회지
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• 제29권1호
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• pp.1-12
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• 2019

Objective: Significant concerns have been raised over chemical exposure and potential health risks such as increased cancer mortality among laboratory workers. The aim of this study was to investigate the overall exposure and unit task exposure levels of researchers in organic synthesis laboratories at universities. Methods: Seventy-seven personal Time-weighted average(TWA) samples and 139 task-based samples from four organic synthesis laboratories at two universities were collected over three days. The concentrations of acetone, chloroform, dichloromethane(DCM), diethyl ether, ethyl acetate, n-hexane, tetrahydrofuran(THF), benzene, toluene, and xylene were determined using the GC-FID. Results: The most frequently used chemicals in the laboratories were acetone, DCM, n-hexane, methanol, and THF. Carcinogens such as benzene, chloroform, and DCM were used in one or more laboratories. The TWA full-shift exposures of researchers to acetone was the highest(ND-59.3 ppm). Benzene was observed above the occupational exposure limit in 18-40% of the samples. The levels of exposure to organic solvents were statistically different by task(p<0.05), while washing task was the highest. Washing was not perceived as a part of the real lab tasks. Rather it was considered as simple dish-washing or experimental preparation and performed in an open sink where exposure to organic solvents was unavoidable. TWAs and task-based concentrations were compared by substance, which suggests that TWA-based assessment could not reflect short-term and high concentration exposures. Conclusions: Laboratory workers may be exposed to various organic solvents at levels of concern. TWA-based measurement alone cannot guarantee holistic exposure assessment among lab workers as their exposures are very dependent on their tasks. Further investigation and characterization for specific tasks and overall chronic exposures will help protect lab workers from unnecessary exposure to chemicals while they perform research.