• Journal of the Korean Institute of Landscape Architecture
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• v.24 no.3
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• pp.164-188
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• 1996

We discussed the formative nature of a city square reffered to be the frame of creating environment in the this study. We raised a question that the place, the size and the form of a city square are out of harmony with a surrounding environmental condition, and examined the functional effect and the formate value of a sunken square at the same time. We got hold of the special shape and the specific character, the distinctive structure, and the influence of the minute temperature of a cuty aquare, and showed the improved direction how to make them better focusing on the target square of a cosmopolitan city of Seoul. Finally, to correct the above-mentioned problems, we emphasized the our traditional city square which is reffered to have a peculiar property, and proposed that a public institutuion should develope the city square, and should make an effort to reflect the design based on the scientific experiment.

• The Korean Journal of Ecology
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• v.11 no.4
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• pp.201-212
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• 1988

Ansan city in the coastal area of the mid-western Korea is known as a newly industrialized city(73.44$Km^2$, 127, 000 persons), with the increase rate of 27.8% in population and mean density of 1, 732 persons/$Km^2$. According to the census of the city(1986), it consists of cultivated field(36.8%), forest(34.2%), industrial area(7.4%), residential area(4.1%) and others(12.5%). The forest vegetation in the city is composed of four associations and two subassociations as follows; Pinus rigida, Pinus densiflora-Rhododendron mucronulatum, Quercus mongolica-Rhododendron mucronulatum and Robinia pseudo-acacia asociation, and Quercus mongolica-Corylus sieboldiana var. mandshurica and Robinia pseudoacacia-Alnus hirsuta subassociation. Various environmental conditions have been changed with the progress of urbanization of the city, since 1977. For example, a heat island phenomenon, which is the air temperature of 2 or 3$^{\circ}C$ higher in the central area than that of the boundary area, and floral changes caused by air pollutants such as decreasing bryophyte species along increasing SO$_2$ concentration.

• Journal of Environmental Science International
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• v.19 no.3
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• pp.281-293
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• 2010

The present study explores time and spatial thermal environment for Daegu, which is a city built on a basin area, according to varying land cover conditions of the earth's surface by analyzing data derived from meteorological observation and satellite images. The study has classified land use by utilizing MODIS satellite images and analyzed land surface temperature. Also, by using data acquired from automatic weather system, the study has evaluated the effects of atmospheric heating caused by city pavements by analyzing the sensible heat flux between the city's land surface and the atmosphere. The results are as follows. 1) Classification of land use in the Daegu area shows 46.64% of urban and built-up area, 1.39% of watersides, 35.19% of forest, 11.43% of crops, and 5.37% grasslands. 2) During the weekdays throughout the year, the land surface temperature was high for Dalseogu, Bukgu, and Seogu regions where industrial complexes could be found. Comparatively, lower temperature could be observed in the woodlands. 3) While the land surface temperature displayed the effects of pushing air upwards during the weekdays in urban areas, the reverse was true for forest regions. During the night, the temperature did not exert any significant influence on air movement.

• Journal of the Korean Society of Industry Convergence
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• v.4 no.3
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• pp.319-327
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• 2001

The objective of this study is to clarify the effect of thermal radiation environments on human thermal comfort, depending on different canyon types and surface materials on the human thermal comfort in a housing complex in Pohang city, Korea. For this purpose, the operative temperature and new effective temperature were calculated based on the modified mean radiant temperature of canyon models variated by the existence of direct radiation existence, surface materials, and the width and length of the street spaces in a housing complex. These indices for the canyon have been calculated from the meteorological data of Pohang city, which include air temperature, relative humidity, air velocity, global solar radiation and cloud. And the monthly averages of these climate factors measured at noon have been used. The results are as follows: (1) It is revealed that the short-wave radiosity reached the human body is affected by direct solar radiation and surface materials, and the long-wave radiosity by canyon types. (2) The existence of direct solar radiation, the kinds of surface materials and canyon types affect operative temperature($OT_n$) and new effective temperature($ET^*{_n}$). (3) The analysis of the human heat balance in the canyon indicates that the influence of radiation on human body is marc likely to be affected by the existence of direct solar radiation on human model.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.38-42
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• 2002

HAZ(Heat Affected Zone of weldm ents) properties were investigated for a high nitrogen austenitic stainless steel with a chemical composition of Fe-0.02C-0.15Si-6.00Mn-10.0Ni-23.0Cr-2.00Mo-0.48N-0.14V. Thermal cycle of HAZ was simulated by the thermal cycle simulator (Gleeble 1500). The heat treatment was applied to the Charpy test size sample without notch under various peak temperatures and/or the holding times condition. V-notch Charpy test was performed at the temperature range of 273~77 K. Metallographic examination also was carried out by using optical microscopy, scanning electron microscopy and transmission electron microscopy. The simulated specimens revealed a slight embrittlement compared with the base materials. The impact toughness of the specimens deteriorated with the decreasing test temperature. The results from Charpy V-notch test, however, showed that significant degradation of absorbed energy caused by brittle fracture was not observed for the specimen tested in the test temperature range.

• KIEAE Journal
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• v.17 no.1
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• pp.49-54
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• 2017

Purpose: Temperature in urban areas increase much more than suburban areas and it is called urban heat island (UHI) phenomenon. There are several solutions to control UHI phenomenon such as green roof system, water space construction, and cool roof system. However, application of green roof system and cool roof system to some of the buildings which compose the city has a critical limit. Therefore, in order to diminish the temperature rising and UHI phenomenon due to climate change of the city, it needs to approach from the viewpoint of site or city, rather than the viewpoint of individual buildings. This study is aims at analyzing UHI phenomenon by characteristics of surface materials and suggesting the solutions to reduce UHI phenomenon by types of complex. Method: Literature reviews were conducted to analyze the cause, mitigating plan, and recent trends of UHI phenomenon. For the simulation analysis, the type of complex was classified 3 representative complex. Based on measured reflectivity, simulation about UHI phenomenon was conducted by setting 4 strategies; albedo of roof, road pavement, green roof system, and vegetating around buildings. Result: As the results of simulating the UHI reduction factor by types of complex, it showed that the effect of temperature reduction on the building roof layer is more effective than adjusting the reflectivity of buildings such as green roof system, planting near the buildings in both the detached house complex, apartment complex, and commercial complex.

• Asian Journal of Atmospheric Environment
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• v.9 no.3
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• pp.194-204
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• 2015

This study analyzed a change trend of ambient temperature over the last sixty years in the largest industrial city in Korea, Ulsan. Linear warming rates in Ulsan over the last 25 (1985 to 2009), 40 (1970 to 2009), and 60 (1950 to 2009) years were 0.0507, 0.0416, and $0.0277^{\circ}C/yr$, respectively. The annual average temperature (AAT) and the annual average of the daily lowest temperature (AADLT) in Ulsan increased 1.3 and $2.9^{\circ}C$, respectively, over the last fifty years (1960 to 2009). The increasing slopes of the AAT and AADLT over the fifty years in Ulsan were higher or much higher than those in neighboring cities and on a global scale. In the comparison analysis of daily average temperature over the most recent ten years, the highest ($15.9^{\circ}C$) was observed in the industrial area followed by the downtown, coastal, suburban, and rural areas with 14.6, 14.5, 14.0, and $12.8^{\circ}C$, respectively. The number of cold days less than $5.0^{\circ}C$ decreased, while the number of hot days higher than $20.0^{\circ}C$ increased. The decreasing slopes in the cold days in lower latitude cities were steeper than those in higher latitude cities in Korea.

• Journal of the Korean Society of Safety
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• v.34 no.1
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• pp.21-26
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• 2019

This paper is purposed to develop hardware for controlling abnormal temperature that can occur environment and component itself in PCS. In order to be purpose, the hardware which is four part(sensing, PLC, monitoring and output) keep detecting temperature for critical components of PCS and can control the abnormal temperature. Apply to the hardware, it is selected to PV power generation facilities of 20 kW in Cheong-ju city and measured the data for one year in 2017. Through the temperature data, it is found critical components of four(discharge resistance, DC capacitor, IGBT, DSP board) and entered the setting value for operating the fan. The setting values for operating the fan are up to $130^{\circ}C$ in discharge resistance, $60^{\circ}C$ in DC capacitor, $55^{\circ}C$ in IGBT and DSP board. The hardware is installed at the same PCS(20 kW in Cheong-ju city) in 2018 and the power generation output is analyzed for the five days with the highest atmospheric temperature(Clear day) in July and August in 2017 and 2018 years. Therefore, the power generation output of the PV system with hardware increased up to 4 kWh.

• Journal of Environmental Impact Assessment
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• v.8 no.2
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• pp.73-82
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• 1999

This study analyzed the relationship between NDVI(Normalized Difference Vegetation Index) and urban heat island in three cities: Daegu, Kyungju, and Pohang for understanding the degree of nature conservation concentrating in the transition zone of them. Daegu city is the third city in Korea which has a dense population. Kyungju is a traditional city which has good nature. Pohang is an industrial city which has those of characters of Daegu and Kyungju. Landsat 1M data in May 17, 1997 were used for the analysis of heat island. There were about four theoretical models to estimate the surface temperature from TM data: Two-point linear model, Linear regression model, Quadratic regression model, and Cubic regression model. In this study, Linear regression model had been utilized to analyze the urban heat island. On the resultant images, the transition zone of Daegu was urbanized more extremely than those of other two cities. It is thought that the analysis of relationship between NDVI and surface temperature, used in this study, is regarded as one of effective methodologies for urban-environmental detection from satellite imageries.

• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.1
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• pp.11-18
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• 2000

Taegu is notorious as hot and dry summer among Korea cities. One of the most important goals of the open space planning is to ameliorate urban climate of the city. The objective of this research is to evaluate the thermal mitigation effect of the cool islands in Taegu metropolitan city. Cool islands of this paper includes parks and rivers surrounded by or adjacent to urbanized areas. Based on the analysis of the thermal band of Landsat TM at May 17, 1997, the thermal mitigation effect of open spaces in the city could be summarized as follows ; Kumho river showed the largest mitigation effect in terms of the width of mitigation zone and temperature difference. Evaporation from wide water surface and evapo-transpiration from riparian grass land could bring into results. Significant mitigation effect of parks covered with forest can be observed. The temperature range of such parks were between 19.05$^{\circ}C$ and 19.44$^{\circ}C$ However, the thermal mitigation effect of Dalsung park and Apsan park was insignificant. The small size and high percentage of hard paving of the former and the relative low density of the residential areas adjacent to the latter could be the main reason. In conclusion, the thermal mitigation effect in urban ope spaces could be detectedby the employment of thermal band data of Landsat TM and GIS buffering technique.