• Korean Institute of Interior Design Journal
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• no.38
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• pp.225-232
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• 2003

The purpose of this study is to select the optimal and minimum transmittance for visual amenity in office buildings. This study progressed as follows. The first, we select 5 films with various transmittance based on the current film makers whose films being used on the windows of office building nowadays and the case study of construction. And then we choose 6 kinds of transmittance as evaluation object including plain glass. The second, we made a mock-up models having different transmittance on the southern windows with model of real scale office building. The third, we select 17 pairs of adjectives for the evaluation of visual comfort on interior or exterior conditions with transmittance factor. The fourth, subjective evaluation experiment was done using selected evaluation adjectives and the result was analyzed. The results are as follows : the minimum transmittance appropriate for the office building is 30%∼40% and the optimal transmittance range is 40%∼60%.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.489-492
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• 2006

The present work was performed to investigate the thermal and hydraulic characteristics of flow inside the plain and turbulator flat tubes for the automobile application. The pressure drop and heat transfer coefficient at laminar, transition and turbulent regimes were studied experimentally and numerically. The flow transition was confirmed by flow visualization and quantitative data. It is proposed equations for the friction and heat transfer coefficient in the fully developed laminar flow inside rectangular tube as function of aspect ratio.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.10a
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• pp.170-174
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• 2002

In this study, the material characterization and the dynamic behavior of 3D orthogonal woven composite materials has been studied under transverse central low-velocity impact condition by means of the micromechanical model using finite elements. To build up the micromechanical model considering tow spacing and waviness, an accurate unit structure is stacked in x-y-z direction repeatedly. First, the mechanical properties of 3D orthogonal woven composites are obtained by means of virtual experiment using full scale Finite Element Analysis based on the DNS concepts, and the computed elastic properties are validated by comparison to available experimental results[9]. Second, using the implementation of this validated micromechanical model, 3D transient finite-element analysis is performed considering contact and impact, and the impact behavior of 3D orthogonal woven composite is investigated. A comparison study will be carried out in terms of energy absorption capabilities.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.11a
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• pp.53-56
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• 2005

In this study, the material characterization and the dynamic behavior of 3D orthogonal woven composite materials has been studied under transverse central low-velocity impact condition by means of the micromechanical model using finite elements. To build up the micromechanical model considering tow spacing and waviness, an accurate unit structure is stacked in x-y-z direction repeatedly. First, the mechanical properties of 3D orthogonal woven composites arc obtained by means of virtual experiment using full scale Finite Element Analysis based on the DNS concepts, and the computed elastic properties arc validated by comparison to available experimental results. Second, using the implementation of this validated micromechanical model, 3D transient finite-clement analysis is performed considering contact and impact, and the impact behavior of 3D orthogonal woven composite is investigated. A comparison study with the homogenized model will be carried out in terms of global and local behaviors.

• Journal of computational fluids engineering
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• v.2 no.1
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• pp.21-28
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• 1997

This paper presents a two-dimensional horizontal implicit model to general circulation in estuaries and coastal seas. The model is developed in non-orthogonal curvilinear coordinates system, using the Interpolating Matrix Method (IMM), in combination with a technique of multi-domain. In the propose model, the Saint-Venant equations are solved by a splitting-up technique, in the successive steps; convection, diffusion and wave propagation. The ability of the proposed model to deal with full scale nature is illustrated by the interpretation of a dye-tracing experiment in the Gironde estuary.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.739-744
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• 2009

The filter has long been used in purification processes for indoor air quality. To determine the deodorization effect of several filter materials in a full-scale air-handling system, the present study has been carried out using a wind tunnel equipped with a heat exchanger and various filter materials, such as commercial fabric, activated carbon(AC) and silver nano-particles attached to activated carbon(Ag-AC). The experiment was conducted using an odor substance with ammonia, acetaldehyde, acetic acid. The results obtained indicate that odor substance is substantially decreased on the moisture condensation on the surface of the heat exchanger. The fabric filter has no effect for removal of odor substances. The deodorization efficiency is found to be approximately 7% in the AC filter, while the deodorization efficiency is increased up to 10% using the Ag-AC filter.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.8
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• pp.1897-1904
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• 1996

This study intends to extract the efficient spectrum characteristics of the fingerpriint image in the fourier domain and to apply them for image enhancement. In order to effectively acquire the spectrum characteristics of the fingerprint in the fourier domain, I set up a 1*64 window as a processing unit and, combining various kinds of the record and overlap lengths, made the power spectrum density estimate for each of those combinations. each spectrum characeristic acquired was applied to a re-synthesis process of the fingerprint image, and, through comparisons and evaluations of the resultant images, an improved gray scale image could be obtained. The validity of this algorithm could be confirmed by the comparison and evaluation fo the binary images which were grained on the established method and the one I used in this experiment.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.6
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• pp.807-813
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• 2004

Wastewater was treated by two different treatment processes; activated sludge process and advanced wastewater treatment process (KNR process) using lab-scale experiment. Two treated wastewater showed good treatment efficiency of organic matter removal, up to 90% removal. Nitrogen and phosphorus were not effectively removed though activated sludge process, while KNR process showed good removal efficiency of nitrogen and phosphorus; 56% nitrogen removal and 95% phosphorus removal. KNR process showed better removal efficiency of organic matter, nitrogen, and phosphorus compared to activated sludge process. Organic matter characterization was tracked though measurement of UV scan, SUVA, and XAD fractionation. Treated wastewater showed higher SUVA value than wastewater influent, indicting less aromatic characteristic of organic matter. XAD fractionation showed hydrophilic fraction decreased though wastewater treatment, suggesting microbes preferentially digest hydrophilic and aliphatic molecules rather than hydrophobic and aromatic molecules of organic matter.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.15-20
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• 2003

During operation process of SIES(Selective ion exchange system) at Kori Unit 2, it was impossible to remove radionuclides such as ion form and Ag-110m, etc., because activated carbon and ion exchange resin of this system are fouled easily by suspended solids and oils in liquid radwaste that was flowed in this system. In this study, an experiment to improve quality of water which was flowed in SIES was performed. and design data of Scale-up pretreatment process were secured. Also, each module design for Microfiltration and Nanofiltration unit of the pretreatment process for SIES was performed.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.1019-1024
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• 2008

A 3 MW class oxy-fuel boiler has been developed to capture $CO_2$ from the exhaust gas. The system is a scale-up of the previous 0.5 MW class system in general. A heat exchanger and a mixer are additionally installed to stabilize the flame for the FGR mode. The system yields the exhaust gas with $CO_2$ concentration over 90% and reduced NO emission to 1/10 of conventional air combustion system.