• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.105-106
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• 2017

Previous studies have confirmed the performance of pH reduction agents using liquid sodium phosphate based ammonium chloride as a pH reduction agent. In this study, the pH reduction performance considering economical and applicability as a practical stage and the property change analysis for the identification of the reaction mechanism of the pH reduction agent were carried out. As a result, the pH reduction performance at a low rate of the pH reducing agent was confirmed. The specific gravity of CaO decreased significantly after XRF analysis. It is also believed that this reduces the amount of Ca(OH)₂ produced and contributes to pH reduction.

• KIEAE Journal
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• v.2 no.1
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• pp.41-48
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• 2002

This study aims to investigate and evaluate the room acoustic designs of a multi purpose gymnasiums which do not use adjustable treatments in order to change the acoustical characteristics. Considering the main uses of gymnasium and auditorium, experiments were carried out using both nondirectional speakers on the stage and loudspeaker installed on the ceiling. The result from the study are as follows; Measured RT under unoccupied condition was a little longer than the expected value, therefore, in the case of occupied condition RT would be close to the optimum value. However, parameters that evaluate intelligibility and speech transmission property appeared to be low and have large differences depending on the measuring points, therefore, more effective sound reflecting surfaces and sound reinforcement systems should be considered.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.1
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• pp.171-180
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• 2012

This study shows that access to urban railway station affects the development of railway station's surrounding zone (RSSZ). For instance, the value of the property in RSSZ is likely to rise on the basis of the before and after the opening of a urban railway. Urban railway system is believed as an important solution to resolve worsening transport problems in metropolitan city. Also, the opening of a urban railway line is expected to affect the change of urban spatial structure, and to have more influence on land price of RSSZ.

• Journal of Biomedical Engineering Research
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• v.15 no.3
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• pp.265-274
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• 1994

This paper proposes a method of noninvasive reflectance light to measure the blood fractional volume (Vb) and oxygen saturation ($SO_2$) of biological tissue. We chose the red light of 660nm and infrared light of 880nm. In Vivo reflectance data were obtained by the physiological changes front the surface of the skin over the calf in human subject. The reflected light intensity from different layers within a biological tissue was measured by specially designed reflectometer to apply photon path diffusion model. The collected data represent the changes of blood (ractional volume and oxygen saturation at each reflected light wavelengths. The data evaluation was assessed by examining the slopes of the plotted indices for the changes in oxygen saturation and blood (ractional volume. The results presented in this paper claim that light reflectance can separately discriminate the change of blood volume and that of oxygenation in muscle and also in skin.

• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.1001-1008
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• 2012

Non-destructive testing (NDT) is a technique used in science and industry to evaluate the properties of a material without causing damage. In this paper we propose a method for segmenting radiographic images of welding in order to extract the welding defects which may occur during the welding process. We study different methods of level set and choose the model adapted to our application. The methods presented here take the property of local segmentation geodesic active contours and have the ability to change the topology automatically. The computation time is considerably reduced after taking into account a new level set function which eliminates the re-initialization procedure. Satisfactory results are obtained after applying this algorithm both on synthetic and real images.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.9-12
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• 2000

Insulators for high-voltage and large-power should be endured mechanically the weight of mold bushing itself and the force of pushed from contact with circuit breaker and conductor. But dielectric breakdown could be occurred result from the external circumstances and internal factors such as chemical reaction, partial discharge, change of temperature and the relation of temperature-time in process of casting. Therefore, to get rid of external and internal factors of dielectric breakdown. Furthermore, to prevent the internal cracks, void, cavity which resulted from the contraction originated on the interface between copper and epoxy resin, formed semi-conductive layer with partially carbon painted on copper bar. The PD properties and the insulation qualities of epoxy molded insulators were improved by roles of cushions for the direction of diameter and natural sliding effects as like separated from conductor for the direction of length.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.279-282
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• 1997

The propose of this study is research and improvement of LiNiO$_2$as cathode material for Lithium secondary batteries. LiNiO$_2$is prepared by heating LiOH . $H_2O$ and Ni(OH)$_2$(mole ratio 1 : 1) on various heat condition. In the result of XRD mesurement, all LiNiO$_2$prepared at this study showed hexagonal structure. In Cyclic Voltammetry, LiNiO$_2$is not conspicous about oxidation peak but oxidation curve change steeply over 3.8V and reduction peak discover at 3.6V. In discharge capacities, specific capacity is higher $O_2$than air when preliminary heated and 75$0^{\circ}C$ than $700^{\circ}C$, 80$0^{\circ}C$ when heated. Therefore, when preliminary heat at $650^{\circ}C$ $O_2$and heat at 75$0^{\circ}C$ carried out, discharge property is the best.

• Journal of Environmental Impact Assessment
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• v.23 no.1
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• pp.51-65
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• 2014

ODA projects such as multi-purpose dam, industrial complex, road construction etc. have resulted in environmental damage and resident relocation including destruction of site of living. Even the grandiose developments as ODA projects have made clear the value clashes between development and environmental conservation, and have brought about conflicts between public interests and public environmental right, and the discordance between public interests and private property rights in the recipient country. This study summarizes and analyses the Korea's ODA projects and will suggest the public participation and governance system based on Saemaul Movement, Strategic Environmental Assessment and Environmental Impact Assessment based on the guideline of OECD DAC, and emphasize Strategic Environmental Assessment and Social Impact Assessment in the procedure of ODA projects. In the future the ODA project should be implemented for the overcome of poverty and response to climate change based on the experience and trial and errors of Korea's compact growth and past ODA projects.

• Textile Coloration and Finishing
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• v.14 no.5
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• pp.294-301
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• 2002

The effects of various parameters on partial decoloration of cotton dyeings using discharge reactive dye were investigated. The decoloration of dyed cotton fabrics with varying pH were very sensitive below 100g/1 of amount of potassium carbonate. Our results did indicate any significant changes in color when the amount of Rongalite C in reducing liquor was increased 10g/l to 200g/l. The steaming time had significant effects on fade-out, with an steaming time of 3~5 min. being sufficient for deceleration build up. The change of color below $130^\circ{C}$ was not significant and it only become evident above $140^\circ{C}$. The additional color changes did not cause by washing under suitable concentrations of oxidation and neutralization agents. The decoloration treatment did not affect the mechanical property of cotton fabrics such as tensile strength.

• Journal of the korean Society of Automotive Engineers
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• v.13 no.1
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• pp.35-45
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• 1991

A linear quarter model of a vehicle suspension system is built and simulated. Especially the so-called sensitivity analysis is conducted in order to show its applicability to design problems, and sensitivity function is determined in the frequency domain. The change of frequency response function is predicted, which depends on the design parameter variation and the property is verified by computer simulation. Typical performance measures, namely, sprung mass acceleration, suspension deflection, and tire deflection are examined. The vehicle model is analyzed for ist performance sensitivity as a function of the system's feedback gains. The variable feedback gains are selected as the spring and damping coefficients. Frequency response, RMS response, and performance index of the performance evaluation variables are considered and three-dimensional and contour plots of response surfaces are formed to examine output sensitivity to suspension feedback. Performance trade-offs over the entire frequency spectrum are identified from the FRF, and that between ride quality and handling characteristics are examined from the RMS responses.