• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.3
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• pp.23-32
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• 2010

The purpose of this study is to quantify human energy budgets for different structures of outdoor spatial surfaces affecting thermal comfort, to analyze the impacts of tree shading on building energy savings, and to suggest desirable strategies of urban greenspace planning concerned. Concrete paving and grass spaces without tree shading and compacted-sand spaces with tree shading were selected to reflect archetypal compositional types for outdoor spatial materials. The study then estimated human energy budgets in static activity for the 3 space types. Major determinants of energy budgets were the presence of shading and also the albedo and temperature of base surfaces. The energy budgets for concrete paving and grass spaces without tree shading were $284\;W/m^2$ and $226\;W/m^2$, respectively, and these space types were considerably poor in thermal comfort. Therefore, it is desirable to construct outdoor resting spaces with evapotranspirational shade trees and natural materials for the base plane. Building energy savings from tree shading for the case of Daegu in the southern region were quantified using computer modeling programs and compared with a previous study for Chuncheon in the middle region. Shade trees planted to the west of a building were most effective for annual savings of heating and cooling energy. Plantings of shade trees in the south should be avoided, because they increased heating energy use with cooling energy savings low in both climate regions. A large shade tree in the west and east saved cooling energy by 1~2% across building types and regions. Based on previous studies and these results, some strategies including indicators for urban greenspace planning were suggested to improve thermal comfort of outdoor spaces and to save energy use in indoor spaces. These included thermal comfort in construction materials for outdoor spaces, building energy savings through shading, evapotranspiration and windspeed mitigation by greenspaces, and greenspace areas and volume for air-temperature reductions. In addition, this study explored the application of the strategies to greenspace-related regulations to ensure their effectiveness.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.132.1-132.1
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• 2010

Anode off-gas of high temperature fuel cells such as MCFC still contain combustible components such as hydrogen, carbon monoxide and hydrocarbon. Thus, it's very important to fully burn anode off-gas and use the generated heat in order to increase system efficiency. In the present study, catalytic combustors have been applied to high temperature MCFC system so that the combustion of anode-off gas can be boosted up. Since the performance of catalytic combustor directly depends on the combustion catalyst, this study has been focused on the experimental investigation on the combustion characteristics of multiple commercial catalysts having different structures and compositions. In order to determine the design conditions of the catalytic combustor, parameters such as inlet temperature, space velocity and excess air ratio have been varied and optimized for combustor design. Results show that $H_2$ in off-gas assists $CH_4$ combustion in a way that it decreases minimum inlet temperature limit and increases maximum space velocity while keeping high fuel conversion efficiency.

• Journal of Environmental Science International
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• v.18 no.7
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• pp.755-765
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• 2009

Some sections of the exhaust system to determine the shape of the duct is to suffer the difficulties by space constraints to install new equipment of the environment post-treatment for existing operation of the power plants. In this paper the large duct in flue gas desulfurization equipments of the 500MW coal-fired power plant on the current operation is numerically analyzed from induced draft fan exit to booster up fan inlet section which is in the narrow space of the exhaust system with four times bending and is connected to emergency duct to bypass the exhaust gas on the emergency operation. The procedure and method using computational fluid dynamics are proposed to maintain the stability of the guide vane with the uniform flow and a minimum pressure loss of exhaust gas in the case of normal and emergency operation between the direction of the flow of exhaust gas duct at different.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.9
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• pp.810-816
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• 2000

Thermal comfort plays an important role in modern office buildings. Four major factors affecting thermal comfort are air temperature, velocity, humidity and radiation temperature. Distribution of these thermal factors in indoor space depends largely on the air flow which is related to the method of supplying and extracting air. In this study, an experimental analysis on indoor thermal comfort is conducted to study the difference between a ceiling supply cooling system and a floor supply one. The two cooling systems are applied to an office space during summer season and the distributions of temperature, velocity, radiation temperature and PMV are measured. Results show that the floor supply cooling system is superior in terms of thermal comfort and energy saving. Studies need to be done, however, to reduce the vertical temperature difference of a floor supply air conditioning system.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.42.1-42.1
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• 2015

We model the Spectral Energy Distribution (SED) of Class 0 protostar L1527 IRS using a radiative transfer code RADMC-3D. In addition to the photometry data from literatures, we include the Herschel/PACS data which well covers the far-infrared SED peak of L1527 IRS, providing precise constraints to the density structure and other physical properties of its circumstellar envelope. Previously, Tobin et al. (2013) presented a dust continuum modeling results using a rotating and infalling envelope (Terebey and Shu, & Cassen 1984 ; TSC envelope), which originally describes a power-law density profile (${\rho}{\propto}r-{\alpha}$) with the power-law index (${\alpha}$) of 1.5. However, we find that Herschel/PACS data are better fitted with a shallower power-law density profile. This smaller power-law might be attributed to a inner envelope. Thus, we fit the SED of L1527 IRS with a Bonnor-Ebert sphere, which is a combination of the inner flat-topped and the outer power-law (${\alpha}=2$) density profiles. This Bonnor-Ebert sphere is often used to explain the density profile of prestellar cores, which is considered the earliest stages of star formation. The well-fitted SED with a Bonnor-Ebert sphere suggests that L1527 IRS might have collapsed from a Bonnor-Ebert sphere rather than a singular isothermal sphere.

• International Journal of Aeronautical and Space Sciences
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• v.10 no.1
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• pp.91-97
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• 2009

It is undertaken systematization of results of satellite and ground observation parameters characterizing a current condition and climatic variability of two selected geographical areas. One of them covers territory of Azerbaijan and another covers a wide area of Caspian See region. Average values and mean square deviations of following values are investigated: outgoing long wave radiation during a day and night (in nebulosity and cloudless). absorbed within a day of the stream of a sunlight of the system in "a terrestrial surface-atmosphere". degree of a covering by clouds of the selected areas during a day and at night, ground temperature values of air. pressure and speed of a wind. Monthly average values of corresponding parameters create a basis of suggested investigations. It has been presented features of a time course of investigated parameters for each month and year in the whole due to the continuously observations since 1982-2000. The scientific problem consists that there are no existed models which authentically would be cover the main aspects of a realities specified changes: they are identified by economic activities. growth of the population and other features of development of a human society or internal fluctuations of biogeophysical/climatic system. Possibilities of predictability of biosphere and climate changes depend on available timely supervision. adequacy of construction of appropriate models. understanding of mechanisms of direct and feedback influences in such complicated systems.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.737-740
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• 2005

Soil moisture, through its dominance in the exchange of energy and moisture between the land and atmosphere, plays a crucial role in influencing atmospheric circulation. To identify the crucial role, it is a common agreement that knowledge of land surface processes and development of remote sensing techniques are of great important scientific issues. This research uses TRMM satellite C band (10.65 GHz) data to retrieve soil moisture on the Tibetan Plateau in Mainland China. Two retrieval schemes that are implemented include the t-(J) model and the R model. The latter one is developed based on a land surface process and radiobrightness (R) model for bare soil and vegetated terrain. Compared with the in situ ground measurements, the soil moisture retrieved from the R model and the t-(J) model with vegetation information obviously appear more accurate than that derived from bare soil model. Retrieved soil moisture contents from the two inversion models, R model and t-(J) model, have a similar trend, but the former appears to be superior in terms of correlation coefficient and bias compared with in situ data. In the future, we will apply the R model with the TRMM 10.65 GHz brightness temperature to monitor long-term soil moisture variation over Tibet Plateau.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.4
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• pp.47-54
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• 2005

The improvement of perspectives on dark and limited underground space could be an important factor in successful underground space development. The Current trend in the apartment underground parking garages requires not only quantitatively energy efficient design and operation but also qualitative improvement of the space. For this, we need to consider two factors: Firstly, to understand the characteristics of the lamps; Secondly, to improve the uniformity ratio of illuminance. In a winter season, a way to keep the uniformity and a method not to lower the indoor illuminance level by cold ambient air should be established. Therefore, a change in interval and arrangement of the lighting fixtures is required. Also, in their operations, the current time-fixed control method needs to be changed into the control which method considers the use pattern.

• Korean Institute of Interior Design Journal
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• v.25 no.6
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• pp.79-88
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• 2016

The purpose of this study was to suggest ways to vitalize residential container architecture by identifying the building process of domestic residential container architecture and analyzing various problems appeared in the process and status of construction related to planning, design, and construction. Conclusion and suggestions of this study are as follows.; firstly, according to the current situation of domestic residential container architecture, the usage was planned mainly for accommodation. Secondly, For planning background of planning preparation stage, economic benefit for long-term residence individuality and diversity for long short term complex residence were the primary planning backgrounds. Thirdly, for floor planning of planning design stage, space planning for various purposes is necessary as creating inter-space, wide LDK space, and loft by using narrow and long container for the long-term residence. Lastly, For construction stage, ways to reduce personnel expenses are being required by reducing the term of works and simplifying the processing stage by running factory production and field construction in parallel. If reduction method of construction cost through energy saving and mass production system is considered in the future, it would be possible to expand the development to dormitory and community housing for university students who are pressured by housing cost.

• International Journal of Aeronautical and Space Sciences
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• v.7 no.2
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• pp.26-32
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• 2006

This paper targets a direct and quantitative prediction of characteristics of unstable waves in a combustion chamber, which employs the governing equations derived in terms of amplification factors of flow variables. A freshly formulated nonlinear acoustic equation is obtained and the analysis of unsteady waves in a rocket engine is attempted. In the present formalism, perturbation method decomposes the variables into time-averaged part that can be obtained easily and accurately and time-varying part which is assumed to be harmonic. Excluding the use of conventional spatially sinusoidal eigenfunctions, a direct numerical solution of wave equation replaces the initial spatial distribution of standing waves and forms the nonlinear space-averaged terms. Amplification factor is also calculated independently by the time rate of changes of fluctuating variables, and is no longer an explicit function for compulsory representation. Employing only the numerical computation, major assumptions inevitably inherent, and in erroneous manner, in up to date analytical methods could be avoided. With two definitions of amplification factor, 1-D stable wave and 3-D unstable wave are examined, and clearly demonstrated the potentiality of a suggested theoretical-numerical method of combustion instability.