• Journal of the Korean Geotechnical Society
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• v.25 no.2
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• pp.25-35
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• 2009

Slope failures are one of the significant disasters which causes lots of human casualties and huge financial losses every year. Previous researches on the slope failure have indicated that most accidents are closely related to the pore water pressure in the slope due to rainfall during the rainy seasons or stormy weather conditions. It would be therefore appropriate to consider the effect of pore water pressure in the design of slopes. As the existing slopes are generally reinforced by plants and other slope protecting measures, their boundary conditions are highly complicated. In this paper an attempt to develop a new modeling and analysis technique of slopes is proposed by including pore water pressure and adopting the coupled finite element method. Non-reinforced and reinforced slope models are considered. Representative analysis showed that the numerical modeling considering pore water pressure is appropriate in slope stability analysis. Flow behavior in the slopes is identified for various hydraulic boundary conditions. It is also shown that the effect of pore water pressure on slope stability is significant.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.5
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• pp.357-363
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• 2003

There have been lots of studies on noise transmission analysis and noise reduction In ducts. In order to reduce the noise transmission in ducts. active noise cancellation techniques have often been employed and a rotation shaft with blades has sometimes been suggested. These Ideas were not successfully commercialized because of the limitation of real life such as size or application difficulties. This study investigated how a rotational shaft with blades could reduce the noise transmission in a duct. To do so, an assembly of the shaft and the $haft housing was built In the middle of a duct. and the clearance between the blades and the housing was 0.2 mm. The noise reduction was experimentally evaluated with respect to the number of blades. the rotation speed, and the rotation or stop. This paper showed that the noise reduction resulted in about 14∼19 dBA regardless of the three test conditions only If the blades always blocked the duct. And. the noise reduction increased due to the higher number of blades and the lower speed of the shaft.

• 한국연소학회:학술대회논문집
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• 2004.11a
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• pp.197-205
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• 2004

Most of gas turbines is operated by the type of dry premixed combustion to reduce NOx emission and economize fuel consumption. However this type operation, combustion induced instability brought failure problems cause by high pressure and heat release fluctuations. Though there has been lots of studies since Lord Rayleigh to understand this instability mechanism and control the instabilities, none of them made matters clear. In order to understand the instability phenomena, a simple experimental study with dump combustor was conducted at the moderate pressure and ambient temperature conditions. From this model gas turbine combustor self-excited instabilities at the resonance mode(200Hz) and bulk mode(10Hz) were occurred and observed at the three points of view; pressure, heat release and equivalence ratio which are acquired by peizo-electric transducer, HICCD camera and acetone LIF respectively. From this results we could see the instability mechanism clear with the account of time scale analysis which explained by the propagation of pressure wave to the upward of mixture stream and convectional transfer of the equivalence ratio fluctuation by this pressure fluctuation.

• Korean Institute of Interior Design Journal
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• v.20 no.6
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• pp.291-299
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• 2011

As our lifestyles have changed due to rapid industrialization and urbanization, new social and communication problems have been caused and there have been lots of discussion on regional communication. For communities to become alternatives with realistic meanings in this changed society, considerations on social and spatial conditions are needed. Therefore, public space which works as a device of physical environment for activation of communities needs more active changes which encourages social communication. In respect to the activation of communities, the following suggestions are given: First, physical devices of a urban plaza should be arranged to support various programs presented along with consideration of human behaviors as users. Second, fundamental facilities of the plaza should accommodate various activities through connections with programs and commercial space. Third, when cultural and historical characteristics of the community are understood, the plaza can form regionality and symbolism through artistic representation. And users can form the identity of community. Fourth, transportation facilities should be separated from or coexist with areas of passengers and the plaza should have its own identity through symbolic sculptures.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.90.1-90.1
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• 2010

The design and fabrication of a metallic bipolar plate-gasket assembly for polymer electrolyte fuel cells (PEMFCs) is defined. This bipolar plate-gasket assembly was prepared by inserting a previously prepared bipolar plate in the specially designed gasket mold. For this aim, a proprietary fluoro-silicone based rubber was injected directly into the bipolar plate borders. Gaskets obtained like this showed the chemically / physically stable and the good sealibilty in typically operating PEM fuel cell conditions. And also, this bipolar plate-gasket assembly shows lots of advantages with respect to traditional PEMFCs stack assembling systems: useful application to automative stacking due to easy handling, reduced fabrication time, possibility of quality control and failed elements substitution. This bipolar plate-gasket assembly was evaluated in the short fuel cell stack and met the leakage requirement for normal operation both in short-term and in long-term operation. Especially, it was confirmed that this gasket could be applied successfully even in the high pressure FEM fuel cell systems(over 2.0 bar in absolute pressure).

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.333-336
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• 2003

For long time, the takeoff and landing control of airship was worked by human handling. With the development of the autonomous control system, the exact controls during the takeoff and landing were required and lots of methods and algorithms were suggested. This paper presents the result of airship take-off and landing by buoyancy control using air ballonet volume change and performance control of pitch angle for stable flight within the desired altitude. For the complexity of airship's dynamics, firstly, simple PID controller was applied. Due to the various atmospheric conditions, this controller didn’t give satisfactory results. Therefore, new control method was designed to reduce rapidly the error between designed trajectory and actual trajectory by learning algorithm using an artificial neural network. Generally, ANN has various weaknesses such as large training time, selection of neuron and hidden layer numbers required to deal with complex problem. To overcome these drawbacks, in this paper, the RBFN (radial basis function network) controller developed.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 1994.05a
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• pp.29-36
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• 1994

The purpose of this study is to suggest the basic design elements for dwelling environment planning of downtown in Taegu.The evaluation of the dwelling environment should be approached from the satisfaction and the cognitive of the residents, that are based on their desire and various values on the conditions of residential area. This paper concerns the satisfaction and the congnitive image structure of the residents in the various dwelling types, from which design elements for dwelling environments can be derived. The results are as folIows: 1) The analysis on the satisfaction of dwell ins environment shows lots of displeasure about the lack of open-spaces and the housing low-quality, neighborhood in Mun-hwa, Korean style housing and the low-rise apartment areas. In order to make the variety types of dowelling in downtown district, the improvement of housing qualities and the expantion of the urban facilities for the open-spaces and communities are need. 2) The design elements of dwelling environments in downtown find out the important planning elements for urban design. The evaluation of the cognitive image structures about the safety and affection should be considered in design for urban dwelling areas.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.8
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• pp.660-667
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• 2008

During the last two decades, lots of efforts have been devoted to resolve thermal stratification phenomenon and primary water environment issues. While several effective methods were proposed especially in related to thermally stratified flow analyses and corrosive material resistance experiments, however, lack of details on specific stress and fatigue evaluation make it difficult to quantify structural behaviors. In the present work, effects of the thermal stratification and primary water are numerically examined from a structural integrity point of view. First, a representative austenitic nuclear piping is selected and its stress components at critical locations are calculated in use of four stratified temperature inputs and eight transient conditions. Subsequently, both metal and environmental fatigue usage factors of the piping are determined by manipulating the stress components in accordance with NUREG/CR-5704 as well as ASME B&PV Codes. Key findings from the fatigue evaluation with applicability of pipe and three-dimensional solid finite elements are fully discussed and a recommendation for realistic evaluation is suggested.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.178-178
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• 1996

Hepatitis B virus (HBV) infection is one of the serious problems in Southeast Asia including Korea because it causes chronic hepatitis, which can easily be transformed In fatal conditions such as cirrhosis and hepatoma. Even though lots of informations on structural characteristics and gene expression mechanisms have been accumulated, the mechanism for HBV-induced hepatocellular injury which is believed to be the consequences of the immunological response is not well understood. In order tn perform immunopathological studies for prevention and treatment of HBV infection, we designed transgenic mice as a disease model which can mimic HBV infection, In this study, a promoter-HBV DNA fragment for the preparation of HBV transgenic mice has been constructed. To add a proper enzyme site on 5' end of HBV gene, total HBV (subtype adr) gene was inserted into BamHI site of pBluescript SK vector and reextracted by PstI-SacI treatment A liver-specific promoter, rat ${\alpha}$ 2u globulin gene promoter, was insrted to pBluescript SK vector and reextracted by BamHI-PstI treatment, Promoter-HBV DNA was constructed by ligation of two fragments using identical PstI sites. For large scale production of promoter-HBV DNA, it was inserted to BamHI-SacI site of pBluescript SK vector.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2006.05a
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• pp.278-283
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• 2006

For the company, the office space is the expensive resource next to human resource. Employees are under the influence of physical characters of the office space. Among them lighting is the most effective factor in physical, biological and psychological for employees. Although there are lots of investments in architectural aspect of the office space, there is almost no investment and consideration about the lighting environment. Therefore this study was trying to find out these things as follow. First, evaluate lighting environment of people who works in the office spaces. Second, find out which factors are more affective in evaluation of lighting environment. And then with these findings this study found what should be considered as important in lighting planning of the office space. As the result of this study, however the majority of the employees are satisfied with current lighting conditions, they are not satisfied with individual operation of lighting. And in office space work type and position changes by age can affect in a large degree more than other factors. Therefore when planning lighting of the office space, it is necessary to figure out work features of Individual and group exactly and accept the difference by positions appropriately.