• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.2
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• pp.156-172
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• 2014

This research measures and compares on-site net radiation energy, air temperature, wind speed, and surface temperature considering various spatial characteristics with a focus on land use types in urban areas in Changwon, Southern Gyeongsangnam-do, to analyze the accuracy of an ENVI-met model, which is an analysis program of microclimate. The on-site measurement was performed for three days in a mobile measurement: two days during the daytime and one day during the nighttime. The analysis using the ENVI-met model was also performed in the same time zone as the on-site measurement. The results indicated that the ENVI-met model showed higher net radiation than the on-site measurement by approximately $300Wm^{-2}$ during the daytime whereas the latter showed higher net radiation energy by approximately $200Wm^{-2}$ during the nighttime. The temperature was found to be much higher by approximately $2-6^{\circ}C$ in the on-site measurement during both the daytime and nighttime. The on-site measurement also showed higher surface temperature than the ENVI-met by approximately $7-13^{\circ}C$. In terms of the wind speed, there was a significant difference between the results of the ENVI-met model and on-site measurement. As for the correlation between the results of the ENVI-met model and on-site measurement, the temperature showed significantly high correlation whereas the correlations for the net radiation energy, surface temperature, and wind speed were very low. These results appear to be affected by excessive or under estimation of solar and terrestrial radiation and climatic conditions of the surrounding areas and characteristics of land cover. Hence, these factors should be considered when applying these findings in urban and environment planning for improving the microclimate in urban areas.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.5
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• pp.340-352
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• 2011

This study was carried out to analyze the change of wind filed and heat island according to the location of the high rise building using micrometeorology numerical model Envi-met3.0. In this study, the real urban planning of Jeonju city was used as input for the location and height of buildings. Modeling was performed for two conditions as input data. Case 1 is that wind direction is SSE and case 2 is W. To analyse the change of wind filed, wind speed results were used. To analyze the change of heat island, temperature results were used. Below the building height, wind speed increased 0.2~2.5 m/s at the inflow area and decreased 0.5~2.0 m/s at the area between the buildings. Above the building height, wind speed decreased 0.1~0.8 m/s near the building complex. On the other hand, wind speed increased 0.2~0.4 m/s in the outside area of the building complex. In the case of temperature, below the building height, temperatures increased $0.01{\sim}0.1^{\circ}C$ in the building complex and leeward area. On the other hand, temperature decreased $0.01{\sim}0.005^{\circ}C$ in the outside area of the building complex. Above the buildings height, temperatures decreased $0.05{\sim}0.2^{\circ}C$ in most of the area.

• 한국지구물리탐사학회:학술대회논문집
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• 2006.06a
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• pp.247-252
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• 2006

This study analysed the sensitivity of the attenuation functions for the seismic hazard estimation. For the seismic hazard estimation, this study used HAZUS software, which is developed originally by FEMA(USA). The scenario earthquake ($M_w=6.0$) is located the Hongsung area, where one of the recent macro earthquakes occurred in 1978. The area for seismic hazard estimation is assumed to be Boryung city in Choongnam-do. Three attenuation functions were applied for the sensitivity analysis. The results show that the attenuation functions have much influences on the seismic hazard on the various types of buildings. Therefore the attenuation function is very important factor for the seismic hazard estimation.

• KSBB Journal
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• v.21 no.5
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• pp.353-359
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• 2006

The purpose of this study is to search the optimal solubilization technology which could be applied to sewage sludge, and is to find the characteristics of biological hydrogen production when the sludge treated by optimal method was used as a sole substrate. As a result of the test, treatment technology mixed with alkali and ultrasonic treatment was very powerful tool for treating sewage sludge with high solubilization, and its ratio and elution rate of organic material was 0.9 and 0.076 $min^{-1}$, respectively. When the sludge treated by above optimal technology was used, 4.4 ml $H_2/g$ VSS of hydrogen was produced. Finally, When the sludge treated by above optimal technology was used, 13.4 ml $H_2/g$ VSS of hydrogen was produced under optimum pH.

• Journal of the Korean Association of Geographic Information Studies
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• v.27 no.2
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• pp.1-18
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• 2024

This study aimed to identify the optimal street tree planting method to improve the summer thermal environment in Seoul, Republic of Korea. The effects of road direction and street tree planting patterns on urban thermal environments using ENVI-met simulations were analyzed. The 68 scenarios were analyzed based on four road directions and 17 planting patterns. The results showed that tree planting had a reducing air temperature, mean radiant temperature, human thermal sensation (PET and UTCI). The most effective planting pattern among all scenarios was low tree height (6m), wide crown width (9m), high leaf area index (3.0), and narrow planting interval (8m). The largest improvement in the thermal environment was the northern sidewalk of the east-west road. Since this study used computer simulations, the difference from real urban spaces should be considered, and further research is needed through field measurement and consideration of more variables.

• Journal of the Korean Institute of Landscape Architecture
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• v.50 no.2
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• pp.1-22
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• 2022

The modification effects of street trees on outdoor thermal comfort in summertime according to tree planting types and road direction were analyzed using a computer simulation program, ENVI-met. With trees, the air temperature and wind speed decreased, and the relative humidity increased. In the case of mean radiant temperature (T_mrt) and human thermal sensation, physiological equivalent temperature (PET) and universal thermal climate index (UTCI), there was a decrease during the daytime. The greatest change among the meteorological factors by trees happened in Tmrt, and PET and UTCI showed similar patterns with T_mrt·The most effective tree planting type on thermal comfort modification was low tree height, wide tree crown, high leaf area index, and narrow planting interval (LWDN). T_mrt, PET and UTCI showed a large difference depending on shadow patterns of buildings and trees according to solar altitude and azimuth angles, and building locations. When the building shade areas increased, the thermal modification effect by trees decreased. In particular, results on the east and west sidewalks showed a large deviation over time. When applying the LWDN, the northwest, west and southwest sidewalks showed a significant reduction of 8.6-12.3℃ PET and 4.2-4.5℃ UTCI at 10:00, and the northeast, east and southeast sidewalks showed 8.1-11.8℃ PET and 4.4-5.0℃ UTCI at 16:00. On the other hand, when the least effective type (high tree height, narrow tree crown, low leaf area index, and wide planting interval) was applied, the maximum reduction was up to 1.8℃ PET and 0.9℃ UTCI on the eastern sidewalks, and up to 3.0℃ PET and 0.9℃ UTCI on the western ones. In addition, the difference in modification effects on T_mrt, PET and UTCI between the tree planting types was not significant when the tree effects were reduced by the effects of buildings. These results can be used as basic data to make the most appropriate street tree planting model for thermal comfort improvement in urban areas in summer.

• Korean Journal of Environmental Agriculture
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• v.19 no.2
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• pp.177-182
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• 2000

Removal rate of swine wastewater containing organic matter was 99 percent in case of high loading rate. The studies of swine wastewater treatment aim to development of process using soil microorganism. Microorganism was devoted to improve the treatment efficiency of the process. Biochemical oxygen demand (BOD) concentration of treated swine wastewater was under 150 mg/L in anaerobic reactor. Also, value of km and Y were $0.73\;hr^{-1}$ and 0.433 g/VSS/g BODrm/d at microorganism of post aeration tank in anaerobic reactor.

• Journal of the Korean housing association
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• v.24 no.3
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• pp.45-53
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• 2013

It is important to secure green spaces to solve the urban heat island phenomenon, which is among problems resulted by high-density developments in metropolitan areas. However, it is hard to secure such green spaces in established urban areas so Green Rooftop development approaches have recently been highlighted and introduced as a solution to the situation. The present study conducts a simulation on residential areas in urbanized regions to quantitatively evaluate the effects of green rooftop developments through a comparison of changes in the air temperatures before and after relevant development projects. According to the evaluation results, when the green roof top development is conducted in the available areas, the temperature is reduced by 0.14 degree. The extension of green project to the entire building showed the reduction of the temperature by 0.29 degree. Based on these results, it can be concluded that the green rooftop development is a practically solution for reducing the air temperature of urbanized areas.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.3D
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• pp.419-431
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• 2009

The core of this study is finding out the efficient band selection or extraction method discovering the optimal spectral bands when applying canonical correlation classifier (CCC) to hyperspectral data. The optimal efficient bands grounded on each separability decision technique are selected using Multispec$^{(C)}$ software developed by Purdue university of USA. Total 6 separability decision techniques are used, which are Divergence, Transformed Divergence, Bhattacharyya, Mean Bhattacharyya, Covariance Bhattacharyya, Noncovariance Bhattacharyya. For feature extraction, PCA transformation and MNF transformation are accomplished by ERDAS Imagine and ENVI software. For the comparison and assessment on the effect of feature selection and feature extraction, land cover classification is performed by CCC. The overall accuracy of CCC using the firstly selected 60 bands is 71.8%, the highest classification accuracy acquired by CCC is 79.0% as the case that executes CCC after appling Noncovariance Bhattacharyya. In conclusion, as a matter of fact, only Noncovariance Bhattacharyya separability decision method was valuable as feature selection algorithm for hyperspectral image classification depended on CCC. The lassification accuracy using other feature selection and extraction algorithms except Divergence rather declined in CCC.

• Applied Chemistry for Engineering
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• v.9 no.3
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• pp.399-403
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• 1998

The gelation characteristics of chitosan of different molecular weight were investigated in terms of concentration and temperature of alkari aqueous solution. The average molecular weights and the degrees of deacetylation of the chitosan used were $2.0{\times}10^5$, $5.2{\times}10^5$, $8.2{\times}10^5$ and 85%, respectively. Sodium hydroxide solution was used as a gelation agent. A simple diffusion model was applied to study the gelation rate. The diffusion coefficients of the gelation agent in the chitosan gel increased with increasing its concentration, temperature of the casting solution, and molecular weight of the chitosan.