• Journal of The Geomorphological Association of Korea
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• v.27 no.2
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• pp.1-17
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• 2020

This study evaluated a debris landform distribution potential area map in the southwest region of the Korean peninsula. A GIS spatial integration technique and logistic regression method were used to produce a distribution potential area map. Seven topographic and environmental factors were considered for analysis and 28 different data set were combined and used to get most effective results. Moreover, in an accuracy assessment, the extracted results of the Distribution Potential area were evaluated by conducting a cross-validation module. Block stream showed the highest accuracy in the combination No. 6, and that DEM (digital elevation model) and TWI (topographic wetness index) have relatively high influences on the production of the Block stream Distribution Potential area map. Talus showed the highest accuracy in the combination No. 13. We also found that slope, TWI and geology have relatively high influences on the production of the Talus Distribution Potential area map. In addition, fieldwork confirmed the accuracy of the input data that were used in this study, and the slope and geology were also similar. It was also determined that these input data were relatively accurate. In the case of angularity, the block stream was composed of sub-rounded and sub-angular systems and Talus showed differences according to the terrain formation. Although the results of the rebound strain measurement using a Schmidt's hammer did not shown any difference in topographic conditions, it is determined that the rebound strain results reflected the underlying geological setting.

• The Journal of Engineering Geology
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• v.7 no.3
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• pp.173-189
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• 1997

A study on the geological structure and geothermal gradient distribution was carried out to evaluate the feasibility of developing a new geothermal field in the Yusong area. It is suggested that geothermal water in the Yusong area is closely related with faults, dykes, and their dipping characteristics with the study of geothermal gradient distribution. A fault of EW direction locates in northern boundary of the study area and another fault of N40{\citc}W$ crosses the EW fault at the western part of the study area. Locations of faults are recognized quite well by lineaments, geophysical exploration and geothermal gradient distribution characteristics. Three sets of dyke are found in the study area. According to the result of the geothermal gradient distribution study, the location of geothermal anomaly belt and dykes coincide each other, and the area has the temperature gradient of larger than 3$^{\circ}C$ between the depths of 0.5m and 1.0m below ground surface. The thermal anomaly belt those temperature gradient is larger than 2.5$^{\circ}C$ between the depths of 0.5m and 1.Om below ground surface is expected in the direction of N80{\citc}W$ in the study area. The dirping of dyke is almost vertical according to the linear distribution of dykes on surface and the results of geophysical survey. From the distribution of geothermal anomaly belt and the locations of dyke, three locations for the development of hot spring water could be recommended and the depth that ensure over 4$0^{\circ}C$ geotheraral water is estimated as 170~200m below the ground surface.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.2
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• pp.195-203
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• 2008

This study collected the latest 30-year (1976~2005) continuous rainfall data hourly recorded at 61 meterological observatories in Korea. The continuous rainfall data was divided into individual rainfall events. In addition, distribution charts of average intervent times between adjacent rainfall events were created to facilitate the application to the overflow risk-based design of storm-water infiltration basin. This study shows that the one-parameter exponential distribution is suitable for the frequency distribution of the average intervent times for the domestic rainfall data. Distribution charts of the average intervent times were created for 4 hour and 6 hour of storm separation time, respectively. The inland Gyeongsangbuk-do and Western coastal area had relatively longer average intervent times, whereas Southern coastal area and Jeju-do had relatively shorter average intervent times.

• Journal of Environmental Science International
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• v.22 no.6
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• pp.667-677
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• 2013

This study aims to examine the actual status of the urban heat island in Daegu by analyzing the data of 17 automatic weather stations installed in the Daegu area. And the results can be summarized as follows: First, regarding the temperature distribution in Daegu by summer time zones, for the 31 days(August 1st till 31st), 18 days showed daily maximum temperature over $30^{\circ}C$, and 11 days indicated daily minimum temperature over $25^{\circ}C$. The day that showed the highest daily maximum temperature was August 5th, which indicated $36^{\circ}C$. Second, about the spatial distribution of time ratio exceeding $30^{\circ}C$ and $25^{\circ}C$, the area with the highest time ratio exceeding $30^{\circ}C$ is mostly the downtown(central area), eastern area, and northern area. Meanwhile, regarding the time ratio exceeding $25^{\circ}C$, the downtown area centering around the central area were high as over 70%, and the outskirts were low as under 65%. Third, considering the temporal distribution of daily maximum temperature and daily minimum temperature, daily maximum temperature was shown around 14:00 to 15:00 while the daily minimum temperature was indicated around 17:00 to 18:00. Daily maximum and minimum temperature were appeared at northeast and downtown, respectively. Fourth, regarding the spatial distribution of tropical days and tropical night days, tropical days showed 77% and tropical night days indicated 42% before and after the 24th and also the 13th each. Tropical days were occurred up to 24 days at northeastern area. And the southwestern area of Daegu showed under 22 days. The downtown showed the 14 days of the tropical night. However, the outskirts indicated relatively few days as under 10 days. Fifth, about the spatial distribution of the average daily temperature range (the difference between the highest temperature and lowest temperature), the central area, the central part of the city, showed the smallest as $7.2^{\circ}C$, and as it was closer to the northern area, it became larger, so in the eastern and northern area, it was over $8.8^{\circ}C$ or so.

• Journal of Power System Engineering
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• v.12 no.2
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• pp.41-47
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• 2008

This article deals with the stress analysis of the friction drive, which transmits the power via the rolling resistance on the contract area between the two rotating bodies. On the contact area, friction drives are normally involved with shear stress due to the transmitted force, as well as normal stress. Thus the stress analysis including the shear stress is necessary for the design of the friction drive. Hertzian results can be used to estimate the normal stress distribution and elastic deflection of the contact area, although the shear stress distribution is not well defined. In order to investigate the shear stress distribution and its effects in a friction drive, we have performed the stress analysis of the spherical continuously variable transmission(CVT) using finite element method. The spherical CVT is one of friction drives, which is used in small power applications. The numerical results show that the normal stress distribution is not affected by the transmitted shear force, and the maximal shear stress is increased in small amount along with the shear force.

• The Korean Journal of Ecology
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• v.20 no.1
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• pp.1-8
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• 1997

This study was conducted to investigate the distributions of the native and introduced dandelins in the western Kyonggido area and to determine the environmental factor influencing distribution of dandelions. One hundered and thirty seven study sites were randomly selected along roadsides in urban areas, arable lands, apartment areas and industry regions, and vegetation, dandelion's seed characters and soil acidity were sureyed. Throughout the areas the introduced dandelions were more widely distributed than the native ones. The native dandelions were scarcely distributed in the developed areas and roadsides. The introduced dandelions were dominantly distributed in the new environments where soils were alkalized by the trban development, road pavement, and construction of new buildings, while the native ones were mostly distributed in the rural area with weakly acid soil. The seed production of the introduced ones were two times more than that of the native ones. The seed of the introduced ones were lighter than that of the native ones. The introduced ones yield seeds more than four times a year. These results suggested the urbanization and the seed characters to bet the two dominant factors influencing the distribution of dandelions.

• Atmosphere
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• v.18 no.4
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• pp.367-386
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• 2008

The Weather Research and Forecasting (WRF) model was designed to identify the role of the Taebaek Mountains in the occurrence of heavy snowfall in Yeongdong area with a strong northeast wind on January 20-21, 2008. To this end, in addition to the control simulation with the realistic distribution of the Taebaek Mountains, a sensitivity experiment that removed the orography over the Taebaek Mountains was performed. The control simulation results showed that the resulting wind field and precipitation distribution were similar to what were observed. Results from the sensitivity experiment clearly demonstrates the presence of orographic lifting on the windward slope of the mountains. It is concluded that the altitude of the Taebaek Mountains is the main controlling factor in determining the distribution and amount of precipitation in the Yeongdong area for the case of heavy snowfall in January 2008.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.247-253
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• 2005

In this stydy, the characteristics of the spatial location based on rural environment pollution facilities which can cause environmental pollution and thus lower the value of rural amenity was analyzed. This study showed that livestock feedlot occupied the highest percentage among the facilities analyzed and the size of facilities increased with increasing distance from the residential area. In addition, the facilities showed two typical characteristics in terms of their spatial distribution; uneven and even distribution which are characterized by concentrated distribution in a certain area and by scattered distribution in a wide area, respectively. As the facilities including livestock feedlot have a great potential to cause environmental problem such as air, water, soil and noise pollution, it is necessary to develop systematic plans for the management and improvement of the facilities.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.5
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• pp.1-9
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• 1995

The purpose of this study is to develop a computer simulation program for analyzing load transmission characteristics of a helical gear system in design stage. In this analysis, the rotational delay, load distribution, root stress, and contact area are investigated. That is, the influence function of deflection is obtained by finite element analysis and the influence function of approach and gear tooth error are considered. Load distribution, rotational delay, and contact area are calculated by solving load-deflection equation which includes these influence functions and tooth error, and the influence function of the bending moment is obtained by finite element analysis. The root stress is calculated by the load distribution and the influence function of the bending moment. The results of the simulation are cross-checked through a specially designed experimental set-up.

• Korean Journal of Ecology and Environment
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• v.52 no.4
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• pp.340-347
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• 2019

The red swamp crayfish (Procambarus clarkia) originated from the North America distribute widely as invasive species throughout the world including Europe, Asia, Africa, North America and South America. The red swamp crayfish is also an invasive species in South Korea. We aimed to characterize the occurrence and distribution pattern of the red swamp crayfish, and evaluate the potential distribution of this species in South Korea. In South Korea, the red swamp crayfish was firstly reported in Seoul in 1996, and recently its occurrence is frequently reported at streams or reservoirs at different regions, showing the expansion of its distribution area. The red swamp crayfish has high potential to occur in the nationwide scale in South Korea because of their biological adaptation, effects of climate change, changes of their habitat condition, and various types of human activities. Finally, our results revealed the necessary to conduct an extensive field survey, to keep up a monitoring program for the occurrence of alien species, and to implement a strategy to prevent the dispersal of alien species in the natural ecosystems.