• Proceedings of the Korea Air Pollution Research Association Conference
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• 2004.11a
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• pp.229-232
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• 2004

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.170-175
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• 1996

대형 튜브구조물의 길이방향으로 전파되는 유도형초음파(Ultrasonic Guided Wave)를 이용한 원자력발존소내의 열교환기류에 대한 새로운 건전성 평가법을 제시한다. 이를 위해, 유도형초음파의 물리적 특성을 이론적으로 해석하였고 실험을 통해 열고환기류에 대한 유도형초음파법의 타당성 여부를 검토하였다. 국부적인 평가(Local Inspection)에 근거한 기존의 평가법에 비해 유도형초음파법은 단시간 내에 보다 효율적으로 전체 열교환기에 대한 신뢰성 검사(Global Inspection)가 가능하며 만족할 만한 민감도(Sensitivity)를 갖고 있음을 보였다.

• Tuberculosis and Respiratory Diseases
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• v.56 no.2
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• pp.144-150
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• 2004

Background : An assessment of the presence and the degree of reversibility of airflow obstruction is clinically important in patients with asthma or chronic obstructive pulmonary disease. However, the time responses of spirometric parameters in response to bronchodilator have not been well investigated. Methods: We studied 15 patients with asthma. Spirometric and mini-Wright peak expiratory flow measurements were performed at 15, 30, 45, and 60 minutes after using single dose($200{\mu}g$) of inhaled bronchodilator, salbutamol. Results : The mean values of forced expiratory volume in one second($FEV_1$) and forced vital capicaty(FVC) were significantly increased at 60 minutes after using bronchodilator in comparison to 15 minutes. And peak expiratory flow rate measured by either mass flow sensor or mini-Wright peak flow meter were significantly increased at 45 minutes after using bronchodilator in comparison to 15 minutes. Conclusions : To appropriate evaluation of the bronchodilator response in patients with reversible airflow limitation, it would be useful measuring either $FEV_1$ or PEF at the later time point 60 or 45 minutes in comparison to 15 minutes after using bronchodilator.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2001.05a
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• pp.104-108
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• 2001

복사에 의한 냉난방은, 장시간 재실하는 방이나 소음, 기류에 민감한 장소에 적합하고 에너지 절약면에서도 유효한 냉난방 방식이라고 알려져 있다. 일반적으로 널리 알려져 있는 바닥난방은 실온의 수직분포가 균일함으로서 인체에 쾌적한 난방방식으로 알려져 있다. 이것에 비해, 바닥의외의 벽, 천장을 활용한 냉난방설비의 쾌적성에 대해서는 아직 충분히 검토되고 잇지 않다. 따라서 본 연구는 물순환식 복사 냉난방장치를 이용하여 겨울철의 천장복사난방이 인체에 미치는 생리적, 심리적영향을 밝히고 복사난방의 유용성에 대해서 검토하는 것을 목적으로 한다. 실험은 일본 나라여자대학 인공기후실을 이용하였고, 실험조건은 실온 18$^{\circ}C$, 21$^{\circ}C$, 24$^{\circ}C$ 천장온도 $25^{\circ}C$, 3$0^{\circ}C$, 35$^{\circ}C$의 조건을 조합하여 7조건으로 설정하였다. 또, 상대 습도 40%, 기류속도 0.1m/s 이하로 일정하게 유지시켰다. 생리적반응으로는 피부온14점과 직장온을 30초 간격으로 측정하였고, 혈압, 심박수, 체중, 체지방율을 측정하고 심리적반응으로는 온열감, 쾌적감등의 항목을 10분간격으로 측정하였다.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2002.11a
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• pp.97-102
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• 2002

Resident's agreeableness anger elevation request by improvement of life environment with economy development is increasing recently. However, research about air current estimation in dwelling environment that make use of air conditioner summer and cooling room is lacking going yet much. We are going to prefer most air current pattern(speed 3 steps of swing) that offer in PAC after figure processing because user's life hysteresis and present air current pattern that is supposed and offer more agreeable environment to room resident.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2002.11a
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• pp.275-278
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• 2002

의복의 쾌적감에 영향을 미치는 인자로는 크게 미세공간의 온도, 습도, 기류인 의복내기후, 의복에 의해 피부가 받는 의복압, 의복과 피부와의 접촉감 등이다. 본 연구에서는 우선적으로 인체의 상반신에서 의복기후분포를 파악하였다. 상반신에서 의복기후 분포를 평가하기 위하여 건강한 남자 10명을 대상으로 25$\pm$1$^{\circ}C$, 습도 50$\pm$5%, 기류는 30cm/sec이하의 환경에서 의복기후를 측정하였다. 실험의복은 100% 면으로 된 긴 팔, 긴바지의 속내의를 착용하게 하였다. 측정결과 가슴에서의 의복내온도는 30.6~34.7$^{\circ}C$였고, 그 평균은 33.3$^{\circ}C$였다. 또한 의복내습도는 35.6~57.9%였고, 그 평균은 38.3%였다. 등에서의 의복내온도의 분포는 31.5~35.4$^{\circ}C$였고, 평균은 33.1$^{\circ}C$였으며, 의복내습도는 36.2~55.3%였으며, 평균은 38.8%였다. 상반신인 가슴과 등에서의 의복내온도와 의복내습도간에는 차이가 없는 것으로 나타났고, 상반신 전체의 의복내온도의 분포는 30.6~35.4$^{\circ}C$, 의복내 습도의 분포는 35.6~57.9%였다.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1480-1486
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• 2011

After installation of platform screen door (PSD) in subway stations, particulate matters (PMs), which are originally ventilated through the platform, are accumulated inside the tunnel of the subway system. It deteriorates an air quality inside the tunnel. To ventilate the accumulated PMs inside the tunnel, the natural ventilator which are located inside the tunnel (namely, tunnel ventilation system) are used as only one circulation system. In addition, the installation of PSD can affect to the aerodynamic variations inside the tunnel, since the PSD system was not considered factor when the tunnel ventilation system was designed. However, the researches about the tunnel ventilation system have not been adequate. Therefore, this study is carried out with two objectives: 1) to measure the velocity of air current by the train-induced wind, when the train passes through the tunnel, and 2) to investigate the typical patterns of air current by quantitatively evaluating the characteristics of inflow/outflow of air current which passes through the natural ventilation system. This study can suggest the basic standard to newly design the tunnel of the subway system as well as the ventilation system.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.5
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• pp.325-332
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• 2014

Growing concerns about harmful influence of radon on human body, many efforts are being made to decrease indoor radon concentration in advanced countries. To develop an indoor radon reduction technology, it is necessary to develop a technology to predict and evaluate indoor inflow and emission of radon. In line with that, the present study performed computational modelling of indoor dispersion of radon emitted from building materials. The computational model was validated by comparing computational results with analytical results. This study employed CFD (Computational Fluid Dynamics) analysis to evaluate the radon concentration and the airflow characteristics. Air change rate and ventilation condition were changed and several building materials having different radon emission characteristics were considered. From the results, the indoor radon concentration was high at flow recirculation zones and inversely proportional to the air change rate. For the different building materials, the indoor radon concentration was found to be highest in cement bricks, followed by eco-carats and plaster boards in the order. The findings from this study will be used as a method for selecting building materials and predicting and evaluating the amount of indoor radon in order to reduce indoor radon.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.5
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• pp.1082-1090
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• 2009

Peak expiratory flow rate(PEF) is a very important diagnostic parameter obtained from the forced vital capacity(FVC) test. The expiratory flow rate increases during the short initial time period and may cause measurement error in PEF particularly due to non-ideal dynamic characteristic of the transducer. The present study evaluated the initial rise slope($S_r$) on the flow rate signal to compensate the transducer output data. The 26 standard signals recommended by the American Thoracic Society(ATS) were generated and flown through the velocity-type respiratory air flow transducer with simultaneously acquiring the transducer output signal. Most PEF and the corresponding output($N_{PEF}$) were well fitted into a quadratic equation with a high enough correlation coefficient of 0.9997. But only two(ATS#2 and 26) signals resulted significant deviation of $N_{PEF}$ with relative errors>10%. The relationship between the relative error in $N_{PEF}$ and $S_r$ was found to be linear, based on which $N_{PEF}$ data were compensated. As a result, the 99% confidence interval of PEF error was turned out to be approximately 2.5%, which was less than a quarter of the upper limit of 10% recommended by ATS. Therefore, the present compensation technique was proved to be very accurate, complying the international standards of ATS, which would be useful to calibrate respiratory air flow transducers.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.2
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• pp.123-130
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• 1992

We check up on whether the one-dimensional station precipitation model of Geogakakos and Bras is suitable to the storm model for Chonju station or not. The fundamental variables of the physically based model consists of the pressure at the cloud top, the hight-averaged updraft velocity(HAUV), and the inverse of the average diameter of the hydrometeors(ADH) at cloud base. And they are parameterized by input variables. The parameters are eastimated by the direct search algorithm of Hooke and Jeeves in this paper. The results show that HAUV and ADH are dominant factors to minimize root mean square error between the calculated and the observed rainfall. In this numerical analysis, the deviation between the calculated and the total observed rainfall is small, otherwise the gap for the time distribution is quite big.