• 한국안전학회지
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• 제37권2호
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• pp.88-96
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• 2022

Widespread infectious diseases are a concern for workers working in confined spaces. However, there is no risk assessment index for the risk of infectious disease in the workplace. Therefore, we propose a simple but effective index model to assess the risk of infectious diseases in the workplace. The proposed model identifies the risk of each workplace through an evaluation sheet comprising the frequency and intensity of the infectious disease. The intensity of an infectious disease is generally governed by the density of workers, whereas frequency is the sum of physical-e nvironmental and human management factors. By multiplying intensity and frequency, the risk of the workplace is derived. Through the proposed model, we evaluate the risks of workers at 15 different work sites. The proposed model clearly reveals what should be improved to keep workers safe from infectious diseases and will be helpful in assessing the risk of contagious disease at the work place.

• 한국해안해양공학회지
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• 제18권3호
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• pp.262-267
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• 2006

연안해역의 COD 항목 농도관리를 위해서는 유역 COD 오염부하량 조사 추정이 필요하나 현재 유역에서의 발생 오염부하량 추정식이 BOD 기준으로 제시되어 있는 실정이다. 해역 오염총량관리를 수행하기 위한 COD 오염부하량 추정식 개발은 많은 관측 및 시간이 소요될 것으로 예상된다. 본 연구에서는 시화호 및 인천 연안유역의 하천 및 공단배수 COD 농도, BOD 농도 비율 변화분석을 수행하였으며, 분석결과를 이용하여 COD 오염부하량 추정기법을 제시하였다. COD 오염부하량 추정은 기존의 BOD 오염부하량 원단위를 이용하여 추정한 방법에 환산계수를 곱하는 방법으로, 환산계수는 평균 + [$1{\sim}3$ 범위의 안전계수] ${\times}$표준편차로 계산할 수 있다. 본 연구결과에 의하면 시화호 및 인천연안의 COD 오염부하량 추정 환산계수는 안전계수 1, 2, 3인 경우 각각 1.7, 2.3, 2.9로 추정되었다.

• 해양환경안전학회지
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• 제24권4호
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• pp.381-388
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• 2018

본 연구에서는 선박의 속력을 고려한 해상교통량 평가 방법을 제안하였으며, 이를 선박의 속력을 고려하지 않은 기존의 방법과 비교하였다. 평가를 위하여 평택 당진항 10일간의 GICOMS 자료를 본 연구에 적용하였다. 그 결과 제안된 방법으로 평가된 환산교통량은 기존의 평가 방법에 비해 4.41(${\pm}0.99$)배 증가하거나, 0.59(${\pm}0.04$)배 감소하는 것으로 나타났다. 제안된 평가 방법을 적용한 각 시간대별 평균 해상교통혼잡도는 기존의 평가 방법 결과에 비해 1.43(${\pm}0.10$)배 높게 나타났으며, 각 시간대별 최대 해상교통혼잡도는 1.62(${\pm}0.34$)배 높게 나타났다. 해상교통혼잡도 최대 평가 결과인 피크타임 해상교통혼잡도는 선박의 속력 분포로 인하여 기존의 평가 방법과 다르게 평가됨을 확인하였다. 결과적으로 선박의 속력은 실용교통용량 평가 시 중요 값으로 적용되기 때문에 해상교통량을 평가할 때 선박의 속력을 고려하여야 할 것으로 사료된다.

• 전기학회논문지
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• 제65권11호
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• pp.1894-1899
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• 2016

In this paper, because the position sensor represents the important factor in BLDC (Brushless DC) motor drives, BLDC motor is necessary that the three Hall-sensors evenly be distributed around the stator circumference in case of the 3 phase motor. The Hall-sensor is set up in this motor to detect the main flux from the rotor. So the output signal from Hall-sensor is used to drive IGBT to control the stator winding current. However, in case of breakdown Hall sensor, we research that the estimation algorithm of Hall sensor signal to detect rotor position and for the speed feedback signals with BLDC motor whose six stator and two rotor designed. In addition, this paper presents a sensorless speed control of BLDC Motor using terminal voltage of the one phase. Rotor position information is extracted by indirectly sensing the back EMF from only one of the three terminal voltages for a three-phase BLDC motor.

• 대한안전경영과학회지
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• 제12권1호
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• pp.199-205
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• 2010

The research proposes the three-factor random measurement models for estimating the precision about operator, part, tool, and various measurement environments. The combined model with crossed and nested factors is developed to analyze the approximate F test by degrees of freedom given by Satterthwaite and point estimation of precisions from expected mean square. The model developed in this paper can be extended to the three useful models according to the type of nested designs. The study also provides the three-step procedures to evaluate the measurement precisions using three indexes such as SNR(Signal-To-Noise Ratio), R&R TR(Reproducibility&Repeatability-To-Total Precision Ratio), and PTR(Precision-To-Tolerance Ratio), The procedures include the identification of resolution, the improvement of R&R reduction, and the evaluation of precision effect.

• 대한안전경영과학회지
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• 제20권2호
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• pp.37-44
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• 2018

The Location Based Service is growing rapidly nowadays due to the universalization of the use for smartphone, and therefore the location determination technology has been placed in a very important position. This study suggests an algorithm that can provide the estimate of users' location by using smartphone sensors. And in doing so we will propose a methodology for the creation and update of indoor map through the more accurate position estimation using smartphone sensors such as acceleration sensor, gyroscope sensor, geomagnetic sensor and rotation sensor.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.716-724
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• 2008

In the case of subsea tunnels, hydro-mechanical coupled analysis is necessary for an exact design and construction. The consideration of the overstretched ground condition is also required because they are usually located at the great depth unlike the usual tunnels. Many researches have been performed on the estimation of relaxed rock mass height. However, there have been no researches on the estimation of relaxed rock mass height under overstretched ground conditions. In this study, therefore, hydro-mechanical coupled analyses were performed under the overstressed ground conditions and the relaxed rock mass heights were estimated based on the contour of the local safety factor around a tunnel.

• 한국안전학회지
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• 제15권4호
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• pp.163-169
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• 2000

본 연구는 노치가 있는 구조물의 피로수명 예측 평가에 대하여 연구하였다. DEN시험편에 대한 피로균열 발생수명과 피로균열 성장수명은 SIF K해석에서 유도한 식과 Paris의 균열성장 식을 사용하였다. 예측평가 결과는 일정하중 진폭 하에서의 실험적 균열성장거동과 잘 일치하는 결과를 보였다.

• 한국식품위생안전성학회지
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• 제14권2호
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• pp.186-194
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• 1999

The Budget method used currently in Codex for estimation of use levels of food additives was investigated and the specific approach that can be applicable for Koreans has been proposed. Theoretical maximum daily intakes(TMDIs) of benzoate, $\rho$-hydroxybenzoic acid ester, butylated hydroxyanisole(BHA), butylated hydroxytoluene (BHT), t-butylhydroquinone(TBHQ), nitrite, nitrate, sorbate, and sulfite were estimated and compared with corresponding acceptable daily intakes(ADIs). Additives requiring further precise evaluation were screened. TMDIs of benzoate, BHA, BHT, TBHQ, nitrite, and sulfite exceeded ADIs. On the other hand, it is appeared that TMDIs of $\rho$-hydroxybenzoic acid ester, nitrate, and sorbate were below ADIs. It is expected that the Budget method may be used as one approach for the estimation of use level and risk assessment.

• 대한안전경영과학회지
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• 제5권1호
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• pp.13-31
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• 2003

This provided a basic frame to analyze the investment effect on the road, railroad, airport and port as a national dimension but it still has a limitation to analyze the specific economic and financial validities to consider the characteristics of the traffic facilities within the area. Conclusively, the aims of this study provide the reasonable evaluation guidelines effectively to the local automatic groups, especially Chungju in the frame of the present evaluation guidelines. We provide the adaptive alternatives on the present systems which are difficult to adapt to the present investment evaluation guidelines; the estimation method of the social economic index and the estimation method of the traffic demand. Additionally, we discuss the research method of the passage actual state for a reasonable estimation of the traffic demand. The result of this study will be activated for the validity check and construction plan of the reasonable traffic investment plan of Chungju city.