• Journal of Environmental Science International
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• v.26 no.12
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• pp.1399-1405
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• 2017

We compared the spatial distribution of several heat stress indices (the Wet-Bulb Globe Temperature(WBGT) index, Environmental Stress Index (ESI), and Modified Discomfort Index(MDI)) for the heat wave of June 6~August 26, 2016, in Daegu. We calculated the heat stress indices using data from the high density urban climate observation network in Daegu. The observation system was established in February. 2013. We used data from a total of 38 air temperature observation points (23 thermometers and 18 automatic weather stations). The values of the heat stress indices indicated that the danger level was very high from 0900-2000h in downtown Daegu. The daily maximum value of the WBGT was greater than or equal to $35^{\circ}C$. The differences in the heat stress indices from downtown and rural areas were higher in the daytime than at nighttime. The maximum difference was about 4 before and after 1400h, and the time variations of the heat stress indices corresponded well. Thus, we were able to confirm that the ESI and MDI can be substituted with the WBGT index.

• Journal of the Korean Solar Energy Society
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• v.24 no.4
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• pp.45-53
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• 2004

In the summer, the irradiated solar heat gain through the roof has an effect on the thermal environment of the top floor units of apartment houses. This paper investigated the differences of the indoor air temperature and thermal comfort index between the top floor unit and the middle floor unit by measuring them at the sample houses. The purpose of this paper is to provide quantitative data about the irradiated solar heat gain during the summertime through the roof of an apartment house and these data to be the source to reevaluate the appropriate roof insulation efficiency. From this study, we obtained the brief results as follows. Indoor air temperature at the top floor unit is $1.2\sim2.2^{\circ}C$ higher than that of middle floor unit. The evaluation of the indoor thermal comfort index at each sample rooms reveals notable thermal differences between the two units. Top floor units need more cooling load during the summertime compared to middle floor units. Therefore, solutions to reduce solar Heat gain at top floor units to be considered.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.4
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• pp.421-430
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• 2006

This paper explores a new methodology of socio-statistical survey to classify environmental perception characteristics and to quantify atmospheric environmental sensitivity of neighboring people around a large industrial complex. In order to compensate intrinsic inclination against environmental problems, Atmospheric Environmental Sensitivity Index (AESI) is proposed as the weighted-summation of four representative questions asking the current status of the local air quality, which are chosen by the factor analysis of questionnaire. Atmospheric environmental perception is tried to be classified into interest/indifference characteristics and rational/emotional perception on environmental issues, positive/negative opinion on the solution of environmental problems. According to the chi-square cross-correlation and two-way layout analyses, it was clearly shown that environmental perception is categorized into two major groups, i.e., the positive-rational group having lower AESI and the negative-emotional group having higher AESI which means more seriously senses the status of local air quality.

• International Journal of Air-Conditioning and Refrigeration
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• v.15 no.3
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• pp.101-107
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• 2007

Indoor air quality becomes of a concern recently in view of human health. This study investigates the air diffusion performance and the air change efficiency of a classroom, when outdoor air is introduced in two different ways in addition to the heating/cooling operation of a ceiling-mounted heat pump. A CFD analysis has been performed to investigate the effect of the discharge angle of the air jets from the heat pump for both parallel and series types of outdoor air system. It is observed that the series type creates more uniform indoor environment compared to the parallel type in general. It can be concluded the discharge angle should not be larger than 40o for the parallel type, in order not to generate thermal stratification in the room.

• Journal of Korean Society for Atmospheric Environment
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• v.26 no.6
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• pp.666-682
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• 2010

The forecasting system for Today's and Tomorrow's PM10 was developed based on the statistical model and the forecasting was performed at 9 AM to predict Today's 24 hour average PM10 concentration and at 5 PM to predict Tomorrow's 24 hour average PM10. The Today's forecasting model was operated based on measured air quality and meteorological data while Tomorrow's model was run by monitored data as well as the meteorological data calculated from the weather forecasting model such as MM5 (Mesoscale Meteorological Model version 5). The observed air quality data at ambient air quality monitoring stations as well as measured and forecasted meteorological data were reviewed to find the relationship with target PM10 concentrations by the regression analysis. The PM concentration, wind speed, precipitation rate, mixing height and dew-point deficit temperature were major variables to determine the level of PM10 and the wind direction at 500 hpa height was also a good indicator to identify the influence of long-range transport from other countries. The neural network, regression model, and decision tree method were used as the forecasting models to predict the class of a comprehensive air quality index and the final forecasting index was determined by the most frequent index among the three model's predicted indexes. The accuracy, false alarm rate, and probability of detection in Tomorrow's model were 72.4%, 0.0%, and 42.9% while those in Today's model were 80.8%, 12.5%, and 77.8%, respectively. The statistical model had the limitation to predict the rapid changing PM10 concentration by long-range transport from the outside of Korea and in this case the chemical transport model would be an alternative method.

• Journal of Internet of Things and Convergence
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• v.7 no.4
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• pp.1-7
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• 2021

Recently, technological differentiation(sensor, AI) of products using IoT technology to satisfy consumer needs in the mature market for smart home appliances has received a lot of positive responses. However, air conditioner products are in the early stages of convergence technology. Therefore, air conditioner products are fields that require ICT technologies for information production, collection, processing, storage, and service development beyond IoT. In this paper, we collect and store contactless bio-signal using IR-UWB radar technology. The blowing direction of the air conditioning is controlled according to bio-signal and user's sleep is monitored to provide an optimal sleep environment. In addition, we propose a service algorithm that can provide comfort with changes in the optimal conditions of air conditioning and emotional lighting depending on the discomfort index environment. Through this study, we developed an intelligent smart air conditioning service platform with ICT technology of bio-signal, discomfort index, and emotional lighting.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.11
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• pp.18-23
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• 2019

The oil immersion method can be used to create objective lenses with long working distances without sacrificing the focusing resolution for laser processing. In this study, a space in which air or oil can be filled was formed in the middle of a lens for analyzing the optical properties of a liquid-oil immersion lens. As the refractive media, air and oils of different refractive index values (1.2 and 1.5, respectively) were used. A simulation was conducted in the ZEMAX software environment using the ray-tracing technique, and the performance of the oil immersion lens was verified by determining its image distortion and focal length (FL) in each medium. In the case of air, the calculated FL was 0.813 mm, whereas the imaged FLs were 1.594 mm and 8.126 mm when the refraction indices were 1.2 and 1.5, respectively. The FL of an oil immersion lens could be increased considerably. In terms of image distortion, the oil immersion lens exhibited little distortion at the center in all cases, but different degrees of image distortion were observed at different points away from the center depending on the refraction index degree.

• Journal of the Korean Institute of Landscape Architecture
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• v.32 no.3
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• pp.51-59
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• 2004

Focusing on WBGT(Wet Bulb Globe Thermometer Index) according to the LAI(Leaf Area Index) variation of trees, this study verifies the effects of urban shade trees on the outdoor thermal environment. As for methodology, air$.$globe temperature, air humidity and WBGT were measured under three shade trees whose LAIs were 2.1, 4.0 and 8.2 respectively at midday(12:00-13:00) of 14 sunny days from the 4th through the 29th day of September 2003. Those factors were also measured at the unshaded areas and compared with the values of shaded areas. The measured site was paved with interlocking concrete bricks. The measurements were analyzed through the ANCOV A(Analysis of Covariance) and the regression routines of SPSS11 for windows (SPSS Inc., 2001). The major findings were as follows. 1. The direct correlation between WBGT and LAI was very low. On the contrary, the WBGT showed close correlation with air$.$globe temperature and air humidity, and the LAI also showed very close correlation with globe temperature. These results tell that dominant shading effect by the tree is on the screening of direct solar radiation which lower the globe temperature and WBGT consequently. 2. While the average globe temperatures and WBGT at unshadowed area were 40.4$^{\circ}C$ and 26.2$^{\circ}C$ respectively, the former under the shade tree with LAI 2.1, 4.0 and 8.2 were 34.5$^{\circ}C$, 32.6$^{\circ}C$ and 30.2$^{\circ}C$, and the latter were 24.6$^{\circ}C$, 24$^{\circ}C$ and 23.4$^{\circ}C$ respectively. 3. The relationship between LAI(x) and WBGT(y) can be presented with the following equation: y = 24.23+1.53 $e^{-x}$+0.36x $e^{-x}$+0.46 $x^2$ $e^{-x}$ ($R^2$ =.98) =.98)

• Journal of Ecology and Environment
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• v.30 no.2
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• pp.143-149
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• 2007

To certify predictability for the times of phenological stages from cumulative air temperature in springtime, the first times of budding, leafing, flower budding, flowering and deflowering for 14 woody plants were monitored and air temperature was measured from 2005 to 2006 at Namsan. Year day index (YDI) and Nuttonson's Index (Tn) were calculated from daily mean air temperature. Of the 14 woody species, mean coefficient of variation was 0.04 in Robinia pseudo-acacia and 0.09 in Alnus hirsuta. However, mean coefficient of variation was 0.30 in Forsythia koreana and Stephanandra incisa and 0.32 in Zanthoxylum schinifolium. Therefore, the times of each phenological stage could be predicted in the former two species but not in latter three species by two indices. Of the five phenological stages, mean coefficient of variation was the smallest at deflowering time and the largest at budding time. In five phenological stages, mean coefficient of variation of YDI was in the range of $0.11{\sim}0.21$ but that of Tn was in the range of $0.15{\sim}0.26$. Therefore, the former was a better index than the latter. Of the species-phenological stage pair, coefficient of variation of YDI was 0.01 in Acer pseudo-sieboldianum - flower budding and below 0.05 in 11 pairs, whereas the YDIs over 0.40 were 4 pairs comprising of Prunus leveilleana - budding (0.51). Coefficient of variation of Tn was 0.01 in A. hirsuta - budding and below 0.05 in 8 pairs. The Tns over 0.40 were 5 pairs comprising of F. koreana - flower budding (0.66).

• Korean Journal of Geomatics
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• v.2 no.2
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• pp.145-151
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• 2002

GIS technique is applied to the analysis of ambient air quality information. For this study, the TMS-monitored air quality information was imported with the geographical information of the TMS stations in Capital Area. It is found that currently available GIS technique has a great extend of potential for air quality management. From the analysis of air quality information, the GIS application demonstrates the poor air quality in the central Capital Area and the it is improved as it travels down to the suburb area. The ambient air quality is also proven to be highly influenced by the ozone concentration in a mid-summer day.