• Journal of the Korean Institute of Landscape Architecture
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• v.34 no.4 s.117
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• pp.105-115
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• 2006

Biotope Area Ratio ($BFF; BiotopFl{\"{a}}chenFaktor$) was developed in Berlin, Germany in 1990s and introduced to Korea in 1999. It is the ratio of the uncovered soil areas which have the natural circulating capability compared to whole development areas. This study seeks for alternative ways to increase Biotope Area Ratio of residential areas in the metropolitan areas of Korea by investigation on new housing developments. The study investigates four new towns including Seoul Eunpyung new town, Yongin Kusung district, Goyang Pungdong and Juyeopdong districts and Hwasung Dongtan district. The Biotope Area Ratio of study sites is between 23.51 % and 40.69%. This result is not relevant to land use conditions, such as the building-ta-land ratio, natural ground green area ratio. This ratio satisfies the minimum requirements of City of Seoul, except 2 sites. Considering that the study sites are relatively low density land use areas compared to Seoul's average, thus, a higher standards is necessary for new town housing complexes. Because Biotope Area Ratio includes artificial ground green area ratio, Biotope Area Ratio is possible can be increased with decreased natural ground green area ratio. And so, when Biotope Area Ratio is applied to new town development, it must go side by side with a definite natural ground green area ratio.

• Journal of the Korean Solar Energy Society
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• v.23 no.4
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• pp.71-80
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• 2003

The purpose of this study is to analyze the window area ratio distribution of building facade in Tokyo metropolitan area. The survey was carried out in Marunouchi, Kanda, Kasai and Todoriki district. The results of this study were as follows; to propose of window area ratio production method, analyzed and surveyed window area ratio of each district building-used and to compared every wall window area ratio of building. Every wall window area ratio of office district is $20\sim40%$, ones of non-office district is 15% or 35%. Residential area results are every wall window area ratio of apartment is 35%, ones of a house is 15%. To increase of office building to appear that Kanda, Kasai added window area ratio. But, Marunouchi, Todoriki wad not this tendency. Above mentioned results are made out database.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.526-531
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• 2003

A cone cylinder is used to obtain variable operation conditions of a sonic ejector-diffuser system. The cone cylinder is movable to change the ejector area ratio, thus obtaining variable mass flow rates. The present study investigates the effects of ejector throat area ratio and operating pressure ratio on the entrainment of secondary stream. The numerical simulations are based on a fully implicit finite volume scheme of the compressible, Reynolds-Averaged, Navier-Stokes equations. The ejector throat area is varied between 3.94 and 8.05, and the operating pressure ratio is changed from 3.0 to 9.0. The results show that the entrainment ratio and mass flux ratio become more dependent on the ejector throat area ratio, when the pressure operating ratio is low. The total pressure losses produced in the present ejector system increase with the operating pressure ratio and the ejector area ratio, but for a given operating pressure ratio, the losses are not significantly dependent on the ejector area ratio when it is larger than about 5.0.

• Earthquakes and Structures
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• v.26 no.2
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• pp.97-115
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• 2024

In this paper, a database consisting of the dynamic shear modulus ratio and damping ratio test data of clay obtained from 406 groups of triaxial tests is constructed with the starting area of Xiong'an New Area as the research background. The aim is to study the nonlinear dynamic properties of clay in this area under cyclic loading. The study found that the effective confining pressure and plasticity index have certain influences on the dynamic shear modulus ratio and damping ratio of clay in this area. Through data analysis, it was found that there was a certain correlation between effective confining pressure and plasticity index and dynamic shear modulus ratio and damping ratio, with fitting degree values greater than 0.1263 for both. However, other physical indices such as the void ratio, natural density, water content and specific gravity have only a small effect on the dynamic shear modulus ratio and the damping ratio, with fitting degree values of less than 0.1 for all of them. This indicates that it is important to consider the influence of effective confining pressure and plasticity index when studying the nonlinear dynamic properties of clays in this area. Based on the above, prediction models for the dynamic shear modulus ratio and damping ratio in this area were constructed separately. The results showed that the model that considered the combined effect of effective confining pressure and plasticity index performed best. The predicted dynamic shear modulus ratio and damping ratio closely matched the actual curves, with approximately 88% of the data falling within ±1.3 times the measured dynamic shear modulus ratio and approximately 85.1% of the data falling within ±1.3 times the measured damping ratio. In contrast, the prediction models that considered only a single influence deviated from the actual values, particularly the model that considered only the plasticity index, which predicted the dynamic shear modulus ratio and the damping ratio within a small distribution range close to the average of the test values. When compared with existing prediction models, it was found that the predicted dynamic shear modulus ratio in this paper was slightly higher, which was due to the overall hardness of the clay in this area, leading to a slightly higher determination of the dynamic shear modulus ratio by the prediction model. Finally, for the dynamic shear modulus ratio and damping ratio of the engineering site in the starting area of Xiong'an New Area, we confirm that the prediction formulas established in this paper have high reliability and provide the applicable range of the prediction model.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.23 no.3
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• pp.105-119
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• 2020

The purpose of this study is to analyze the hydrologic cycle environment of Gyeongui Line Forest Park, a linear city park, in order to improve hydrologic cycle systems in urban areas. The method of the study is the Biotope Area Ratio and the Permeable ratio survey. The study subject is the Gyeongui Line Forest Park, created in 2016 as a linear park in Seoul. The results showed that the Biotope Area Ratio improved by 31.2% (31,927㎡) from 35.7% (36,480㎡) in 2000 to 66.9% (68,407㎡) in 2019 on a site area of 102,117㎡. Next, the Permeable ratio improved by 43.8% from 29.0% to 72.8%, and the impermeable ratio decreased by 43.8% from 71.0% to 27.2%. The Biotope Area Ratio exceeded the target ratio of 60% by 6.9%, set by the Ministry of Environment. The ratio of green space exceeded the target ratio of 60%, by 4.0%. And so they contributed to the improvement of the hydrologic cycle by the creation of the Gyeongui Line Forest Park. Urban parks need to exceed the Biotope Area Ratio and the green area ratio of the legal standards, especially when creating large parks of over 100,000 square meters, in the era of climate change. It is necessary to continuously plant trees in the space where trees can be planted, and to contribute to the improvement of the hydrologic cycle system and urban heat island effect by conducting three-dimensional.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.5 s.236
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• pp.554-560
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• 2005

A new method to improve the efficiency of a hydrogen fuel cell system was introduced by using variable sonic/supersonic ejectors. To obtain the variable area ratio of the nozzle throat to ejector throat which controls the mass flow rate of the suction flow, the ejectors used a movable cylinder inserted into a conventional ejector-diffuser system. Experiments were carried out to understand the flow characteristics inside the variable ejector system. The secondary mass flow rates of subsonic and supersonic ejectors were examined by varying the operating pressure ratio and area ratio. The results showed that the variable sonic/supersonic ejectors could control the recirculation ratio by changing the throat area ratio, and also showed that the recirculation ratio increased fur the variable sonic ejector and decreased for the variable supersonic ejector, as the throat area ratio increases.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.2035-2040
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• 2004

A cone cylinder is used to obtain variable operation conditions for the sonic ejector-diffuser system. The cone cylinder is designed to move upstream and downstream to change the ejector throat area ratio, thus obtaining variable mass flow rates. The present study investigates the effects of ejector throat area ratio and operating pressure ratio on the entrainment of secondary stream for the variable sonic ejector system. In experiment, the ejector throat area is varied in the range from ${\psi}=11.88$ to 66.69, and the operating pressure ratio from $p_{0p}/p_a=1.25$ to 9.0. The results show that the variable sonic ejector system is suitable for a required entrainment ratio of secondary stream by altering the ejector throat area ratio and operating pressure ratio.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.414-417
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• 2004

A cone cylinder is used to obtain variable operation conditions for the sonic ejector-diffuser system. The cone cylinder is designed to be shifted upstream and downstream to change the ejector throat area ratio, thus obtaining variable mass flow rates. The present study investigates the effects of ejector throat area ratio and operating pressure ratio on the entrainment of secondary stream for the variable sonic ejector system. The study is carried out experimentally. The ejector throat area is varied at the range from Ψ= 11.88 to 66.69, and the operating pressure ratio is changed from $P_{op}$ / $P_{a}$=1.25 to 9.0. The results show that the variable sonic ejector system can be operated to obtain specific entrainment ratio of secondary stream by altering the ejector throat area ratio and operating pressure ratio.o.

• Journal of Environmental Science International
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• v.16 no.4
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• pp.415-423
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• 2007

This study assessed the characteristic of BTEX (Benzene, Toluene, Ethylbenzene, Xylene) concentration ratios of industrial emission sources and the neighborhoods of industrial area, fuel such as gasoline, light oil, LPG, and similar gasoline, and ambient air in Daegu. The BTEX in aromatic compounds was the most abundant VOC in Daegu. The BTEX ratios were (0.2:2.6:1.0:1.8) for the neighborhoods of industrial area, (2.6:11.3:1.0:1.2) for residential area, (2.2:11.0:1.0:1.6) for commercial area, (1.0:14.9:1.0:1.3) for industrial area, and (0.2:2.6:1.0:1.8) for the neighborhoods of industrial area. Average BTEX ratios in Daegu were B/T ratio (0.1), B/EB ratio (1.5), B/X ratio (1.1), T/EB ratio (12.6), T/X ratio (10), EB/X ratio (0.7), Expecially, B/T ratio in Daegu was similar as the other cities, Bangkok, Manila, and Hongkong. Comparing other cities with B/T ratio, the main sources of VOC were vehicular exhaust and emission of industrial facilities. Furthermore, BTEX correlation were evaluated at the emission sources and regional areas. Results showed that correlation coefficient values of emission sources, fuels and neighborhood of industry were significant magnitude above 0.65(p<0.01). Also, there showed highly significant correlations among BTEX. Calculated correlation coefficients of ambient air sampling sites were $0.61{\sim}0.954$ for commercial /residential area and $0.613{\sim}0.998$ for industrial area. However, they showed different correlation between commercial/residental area and industrial area. It implied that the emission sources were different from each area.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.9 no.1
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• pp.15-19
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• 2013

In this Study, effect of core position, area ratio and orientation of building on energy load is examined using TRNSYS17. This parameters are major parameters of the conceptual design stage. Reference model is square floor plan($1,444m^2$), centered core and 29% core area ratio. As the results, without considering the building orientation, the annual heating load of central building with 1:1 area ratio is lowest ($10.33kWh/m^2yr$) and the annual cooling load of off-central building with 1:1 area ratio is lowest ($59.27kWh/m^2yr$). As area ratio is bigger, cooling load is lower and heating load is higher. But if we consider building orientation, orders of heating load and cooling load are changed for area ratio and orientation.