• Journal of the Korean GEO-environmental Society
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• v.13 no.11
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• pp.51-60
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• 2012

In order to characterize the shear strength of the frozen sand for foundation design in cold region and prediction of adfreeze bond strength, many researchers developed test techniques and carried out many tests to analyze shear strength properties of the frozen sand for half a century. However, many studies for shear strength properties of the frozen sand have been carried out with limited circumstances, even though shear strength of the froze sand can be affected by various influence factors such as soil type, temperature conditions, and magnitude of normal stress. In this study, direct shear test equipment was used to analyze the shear strength characteristics of the frozen sand. Direct shear test equipment was designed for cold weather, and the direct shear tests were carried out inside of large-scaled low temperature chamber. Three soil types-two uniform sands and one well graded soil were used to analyze the shear strength of the frozen sand with three different temperature conditions and three different vertical confining pressures. In this research, a series of direct shear tests for shear strength of the frozen sand have been conducted to demonstrate the efficiency of effectiveness of the test equipment and low temperature chamber. This research also showed that shear strength of the froze sand increased with decreasing temperature condition, but the influence of vertical confining pressure was insignificant to the shear strength of the frozen sand.

• Journal of Industrial Convergence
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• v.18 no.4
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• pp.61-66
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• 2020

Recently, attempts have been made to use data to operate games, seasons, and teams in professional baseball. Therefore, in this study, we collected baseball game records and analyzed the relationship between on-base rate and pitching count induction, and this was defined as the third record for non-game factors such as discomfort index, which includes the weather application data. When the discomfort index was over 75, the pitcher's induction of pitching was high, and when the discomfort index was less than 69.9, the on-base rate was high, but when the discomfort index was 70 or more and less than 75, the batter's on-base performance was the lowest. Through the results of the study, it could be inferred that the discomfort index, the batter's on-base rate, and the number of induction pitches are related, and that it is highly likely to be related to the pitcher's performance. Through this study, we could see the possibility of defining a cumulative/ratio record defined as the primary record and a saver metric defined as the secondary record, and a third, tertiary record linking data outside the game.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.3
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• pp.26-67
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• 2020

Synthetic Aperture Radar(SAR) is able to photograph the earth's surface regardless of weather conditions, day and night. Because of its possibility to search for hydrological factors such as soil moisture and groundwater, and its importance is gradually increasing in the field of water resources. SAR began to be mounted on satellites in the 1970s, and about 15 or more satellites were launched as of 2020, which around 10 satellites will be launched within the next 5 years. Recently, various types of SAR technologies such as enhancement of observation width and resolution, multiple polarization and multiple frequencies, and diversification of observation angles were being developed and utilized. In this paper, a brief history of the SAR system, as well as studies for estimating soil moisture and hydrological components were investigated. Up to now hydrological components that can be estimated using SAR satellites include soil moisture, subsurface groundwater discharge, precipitation, snow cover area, leaf area index(LAI), and normalized difference vegetation index(NDVI) and among them, soil moisture is being studied in 17 countries in South Korea, North America, Europe, and India by using the physical model, the IEM(Integral Equation Model) and the artificial intelligence-based ANN(Artificial Neural Network). RADARSAT-1, ENVISAT, ASAR, and ERS-1/2 were the most widely used satellite, but the operation has ended, and utilization of RADARSAT-2, Sentinel-1, and SMAP, which are currently in operation, is gradually increasing. Since Korea is developing a medium-sized satellite for water resources and water disasters equipped with C-band SAR with the goal of launching in 2025, various hydrological components estimation researches using SAR are expected to be active.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.3
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• pp.12-21
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• 2013

This paper deals with a comparative analysis of changes in cognition of city image of Daegu City, focusing on image of representative and environmental conditions. Two-questionnaire surveys were conducted to compare the change of image cognition between the last decades. Major results are: Firstly, the most frequent representative images of Daegu City were hot weather, Palgong Mountain, textile industry, etc. and representative places were Palgong Mountain, Dongsung-ro Street, E world(Woobang Land), etc. Compared to the results of year 2000, the frequency of apple, and textile industry were remarkably decreased. Secondly, mean scores of image rating for environmental conditions were comparatively high in human environment such as women, and kindness. By individual variables, accessibility to Daegu City, women, living environment such as shopping, showed higher mean scores. Generally, mean scores of 2011 survey were higher than that of 2000. Thirdly, major factors affecting city image were human environment, living environment, natural environment, and transportation environment, respectively. These results can be used as a basic data for strategies to improve higher brand image of Daegu City.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.6 no.3
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• pp.79-85
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• 2003

Human beings have pursued development and economic betterment; thus, enhancing convenience and prosperity. A flourish of human civilization upon the industrialization results a massive urbanization. However, human beings have connived the environmental importance in the course of rapid urbanization. The environmental quality now becomes one of the most important factors that determine the quality of life in a city. Many studies were proceeded about the heat island effect in large cities. In general, most studies have been done to investigate urban microclimate phenomena using meteorological network or AWS (automatic weather station) data. Those preceding studies do not seem to sufficiently reflect the and thus, failed to show regional representative. In this study, temporal Landsat TM satellite imageries of May 20, 1987 and May 21, 1999 were 뻐d in order to detect the surface temperature of the study area using the band 6 ($10.4{\mu}m{\sim}12.5{\mu}m$). The surface temperature distribution detected by the band 6 of Landsat TM was over layed with the land cover classification data in order to investigate the temperature difference of the paved road and the riparian areas of the stream. As a result, a surface temperature difference as much as $3^{\circ}C$ between the paved road and the riparian areas with vegetation was observed. This study concludes that the land cover change is one of the main causes of urban heat island effect which may be closely affected by the paved areas and roads. Besides, the change of the atmospheric temperature followed by the urban secular change could have been confirmed. In the case of Yangjaecheon stream which underwent a heavy environmental restoration in 1995, the temperature was decreased as much as $0.6^{\circ}C$ after the restoration. The results of this study is expected to contribute to develop an urban space in harmony with the healthy human life and the environment respecting the crucial role of vegetation to stabilize the urban environmental dynamics.

• Journal of Korean Society of Transportation
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• v.35 no.2
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• pp.129-142
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• 2017

Accident Black Spot Improvement Project is the representative road safety intervention to eliminate environmental risk factors on the roadway by installing road safety facilities. Although it is one of the main road safety projects in Korea, there has been a lack of effort analyzing the traffic accident reduction effects of this project. In this study, therefore, we selected 4,171 road black spots from 2004 to 2013 and investigated the traffic accident reduction effects of 5 road safety facilities by using "Comparison Group(C-G)" method. Through the analysis, it was found that the number of traffic accidents were lowered by 4.45% with traffic islands, 32.17% with road paved markers, and 24.13% with speed cameras, respectively. However, 0.61% with pedestrian fencing and 1.67% with skid resistant pavement were increased on the other hand. In addition, we also analyzed traffic accident reduction facilities' performance on specific types of collision mentioned in manual on road safety facilities by Ministry of Land, Infrastructure and Transport. It was shown that the number of bad weather traffic accidents were reduced by 52.96% with road paved markers, pedestrians accidents were reduced by 62.77% with pedestrian fencing and rear-end collisions were reduced by 26.00% with skid resistant pavement.

• Journal of the Korean earth science society
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• v.40 no.6
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• pp.599-605
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• 2019

Rice yield (kg 10a^-1) in South Korea was estimated by meteorological variables that are influential factors in crop growth. This study investigated the possibility of anticipating the rice yield variability using a simple but an efficient statistical method, a multiple linear regression analysis, on the basis of the annual variation of meteorological variables. Due to heterogeneous environmental conditions by region, the yearly rice yield was assessed and validated for each province in South Korea. The monthly mean meteorological data for the period 1986-2018 (33 years) from 61 weather stations provided by Korean Meteorological Administration was used as the independent variable in the regression analysis. An 11-fold (leave-three-out) cross-validation was performed to check the accuracy of this method estimating rice yield at each province. This result demonstrated that temporal variation of rice yield by province in South Korea can be properly estimated using such concise procedure in terms of correlation coefficient (0.7, not significant). Furthermore, the estimated rice yield well captured spatial features of observation with mean bias of 0.7 kg 10a^-1 (0.15%). This method may offer useful information on rice yield by province in advance as long as accurate agro-meteorological forecasts are timely obtained from climate models.

• Korean Journal of Remote Sensing
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• v.34 no.3
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• pp.481-494
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• 2018

The accurate radiative transfer model simulation is essential for an accurate ozone profile retrieval using optimal estimation from backscattered ultraviolet (BUV) measurement. The input parameters of the radiative transfer model are the main factors that determine the model accuracy. In particular, meteorological parameters such as temperature and surface pressure have a direct effect on simulating radiation spectrum as a component for calculating ozone absorption cross section and Rayleigh scattering. Hence, a sensitivity of UV ozone profile retrievals to these parameters has been investigated using radiative transfer model. The surface pressure shows an average error within 100 hPa in the daily / monthly climatological data based on the numerical weather prediction model, and the calculated ozone retrieval error is less than 0.2 DU for each layer. On the other hand, the temperature shows an error of 1-7K depending on the observation station and altitude for the same daily / monthly climatological data, and the calculated ozone retrieval error is about 4 DU for each layer. These results can help to understand the obtained vertical ozone information from satellite. In addition, they are expected to be used effectively in selecting the meteorological input data and establishing the system design direction in the process of applying the algorithm to satellite operation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.3
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• pp.285-294
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• 2020

This study investigated the use of Ground Penetrating Radar (GPR) over a two-decade period on public roads, focusing on the electromagnetic characteristics of the pavement dielectrics and attenuation. From the results, a typical range of characteristic value, influencing factors, and a correction method were suggested. The typical dielectrics of asphalt pavements were 4-7, as measured by an air-coupled 1 GHz GPR antenna. The dielectrics of concrete pavements were very large in the early age, but were drastically reduced with ageing. Ten years on, collection was in the range of 6-12. The dielectrics were proportional to the relative humidity (R.H.) of the atmosphere. The effects were reduced to one eighth with an overlay. Attenuation generally increased with thickness of the road layer, and also increased where there was damage. The GPR results could also vary depending on the weather conditions as well as on the characteristics of the GPR equipment, even at the same frequency. Therefore, GPR surveys should be performed on road surfaces without debris on a single, fine day. The reliability of the GPR analysis could be improved by cores and equipment calibration with other non-destructive test surveys.

• Journal of Conservation Science
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• v.32 no.3
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• pp.395-402
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• 2016

The impact of a large water control project on surrounding environment(temperature and relative humidity, precipitation, wind speed, present weather and visibility) was monitored. The survey have targeted on Silleuksa temple which is located in the waterside. The number of foggy days emerged as an environmental factor that can cause damage to cultural heritage. Under construction of weir since 2011, monthly relative humidity of Yeoju and Icheon was dropped to 9.6%. It depends on decrease in the number of raining days and precipitation of each year. Silleuksa temple is contiguous to Namhan River and only 100 m away from the waterside. Average wind speed is 0.5 m/s. Silleuksa has a site environmental factors which is often foggy. The number of foggy days of Silleuksa temple declined to 53 days soon after weir's completion. In case of fog, relative humidity of outside was higher than that of outside and inside of Josadang Shrine. Relative humidity difference of outside and inside of Josadang Shrine was 5.4% on average. Relative humidity of the number of foggy days is 6.3% higher on average than that of fine days. The width and dimensions of Namhan River increased by 1.45 times after weir's construction. It can change the number of foggy days. A long-term monitoring is positively necessary on fog occurrence and relative humidity.