• The Journal of the Acoustical Society of Korea
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• v.29 no.3
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• pp.173-183
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• 2010

In this paper, acoustic transmission characteristics are theoretically considered on a cylindrical cavity system. The cylindrical cavity system is a simplified model of the acoustic cavity of King Seongdeok Divine Bell and it consists of a main cavity, a gap and an auxiliary cavity, Under a point sound source in the main cavity, acoustic frequency response property is determined and acoustic modes are analysed. The results are compared with those by the boundary element analysis using SYSNOISE. Using the proposed theoretical method, the effect of the auxiliary cavity and the gap on the resonance frequency and sound transmission characteristics is identified. Finally the best combination of the auxiliary cavity and gap is determined for the maximum transmission of the source frequency.

• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.5
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• pp.41-47
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• 2009

Numerical computations were carried out to analyze the effect of a sub-cavity at several inlet Mach numbers on the control of cavity-induced pressure oscillations in two-dimensional supersonic flow. The present passive control method, the sub-cavity applied to the front wall of a square cavity, was studied for the inlet Mach numbers of 1.50, 1.83 and 2.50. The results show that the sub-cavity is effective in reducing the oscillations, and a resultant amount of the reduction depended on the inlet Mach number, the length of flat plate, and the depth of sub-cavity used as an oscillation suppressor.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.119-122
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• 2009

Numerical computations were carried out to analyze the effect of inlet Mach number and sub-cavity on the control of cavity-induced pressure oscillations in two-dimensional supersonic flow. A passive control method wherein a sub-cavity was introduced on the front wall of a square cavity was studied for Mach numbers 1.50, 1.83 and 2.50. The results showed that sub-cavity is effective in reducing the oscillations at different inlet Mach numbers. The resultant amount of attenuation of pressure oscillations depended on the inlet Mach number, length of the flat plate, and the depth of the sub-cavity used as an oscillation suppressor.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.345-348
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• 2008

The subcavity passive control technique is used in present study. Cavity-induced pressure oscillation has been investigated numerically for a supersonic three-dimensional flow over rectangular cavities at Mach number 1.83 at the cavity entrance. The three-dimensional, compressible Navier-stokes equations are numerically solved based on a fully implicit finite volume scheme. The results showed that the resultant amount of attenuation of cavity-induced pressure oscillations was dependent on the length and thickness of the flat plate.

• The Hankook-Saengyark Bo
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• no.229
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• pp.6-6
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• 1998

`동충하초술` 특산품 개발(수원시-농협 공동, 피로회복등 효과) - 한약재 이용 양계 보조사료 개발

• The Journal of Korean Association of Computer Education
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• v.14 no.1
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• pp.35-43
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• 2011

The purpose of this research is to confirm that how the support type of the assistant teacher changes the students' creativity and self-efficacy in the Robot Education, particularly Robot Edu-Camp. The study objects are 72 elementary students for 8 groups; each group has 9 students, and 4 groups of them have the assistant teachers and others are supported by giving some feedbacks for their questions or some information if they need. The assumption of this study sets up as in the following; there are no differences for the students' creativity and self-efficacy between the supporting of the assistant teachers with making robots and programing together and the giving feedbacks and information if students need. To verify this assumption, we use the nonequivalent control group in the pretest-posttest designs. The result is as in the following. There's no meaningful differences of the students' creativity by the support type of the assistant teachers. But in the self-efficacy, the groups which are giving feedbacks and information if they need have more higher level of achievement than others. The result shows that if the assistant teachers help the students directly, the students' levels of the self-direction, and control are low because they lean on the teachers. This will give you some implications to the follow-up studies about the support type of the assistant teachers in the Robot Education.

• Computational Structural Engineering
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• v.4 no.3
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• pp.36-39
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• 1991

이미 상당부분 CAD시스템이 사용되고 있는 건축설계 분야는 새로운 전환기를 맞이하고 있다. 제도보조도구로서의 컴퓨터가 일반화되어 널리 확산되어가는 반면 진정한 전산보조설계를 위한 새로운 시도와 연구가 각 분야에서 시작되고 있다는 것이다. 이러한 활발한 움직임의 바탕에는 컴퓨터에 대한 사회적인 인식의 변화가 흐르고 있으며 되돌릴 수 없는 발전의 역사를 감지할 수 있다. 따라서 새롭게 다가오는 변화를 보다 능동적으로 수용하기 위해서는 기반이 되는 분야별 CAD/CAE를 점검하고 엔지니어링데이타베이스를 구축해 나가는 것이 현재 건축설계 분야에서 시도해야 할 중요한 일이다. 특히 엔지니어링데이타베이스의 경우 하나의 사무소에서 단독으로 구축하는 것은 불가능한 일이므로 학회나 유관단체 등의 선도적 역할에 힘입어 업계에서 공동으로 구축하고 활용하는 방안이 조속히 논의되기를 기대한다.

• Electronics and Telecommunications Trends
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• v.14 no.4 s.58
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• pp.126-128
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• 1999

GIANT(Gigabit Information-processing And Networking Technology)는 초고속 정보통신망 환경에서 취급되어지는 멀티미디어 정보를 처리할 수 있는 플랫폼을 의미한다. GIANT는 분산 환경에서 컴퓨터를 이용하는 사용자간 공동작업을 가능하도록 지원하는 시스템으로 원격자의 사용자들은 영상/음성을 이용한 통신 기능과 정보/아이디어를 공유하는 데 필요한 보조 도구들을 활용하여 상호 대화 및 협동작업을 수행할 수 있다.

• Journal of Korean Institute of Architectural Sustainable Environment and Building Systems
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• v.12 no.6
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• pp.567-578
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• 2018

The purpose of this study was to evaluate condensation prevention for condensation vulnerable areas around built-in furniture of apartment buildings by applying auxiliary heating device. Recently, the condensation and mold problems of apartment buildings has been growing due to high insulation and high air-tightness performance for energy saving. Condensation at built-in furniture were generally found in winter at the of furniture's back panels, adjacent surfaces of wall, floor and ceiling. These problems are related to the weather conditions and indoor room conditions in winter. To solve these problems, auxiliary heating device was developed and could be installed. The aim of paper is to analyze the thermal environment around the built-in furniture which were applied and not applied auxiliary heating device in winter. In results, it was possible to increase the surface temperature of vulnerable areas around built-in furniture by applying auxiliary heating device, and to minimize condensation problems by using the minimum device.

• Journal of Biomedical Engineering Research
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• v.23 no.1
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• pp.33-38
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• 2002

A Ventricular Assist Device(YAD) is used to support the injured natural heart So. when considering a control algorithm for YAD. it is important to reduce a natural heart's load to enhance its recovery condition. To reduce natural heart's load, a counterpulsation algorithm is used commonly. In this study, we developed a counterpulsation control algorithm for moving-actuator type VAD and tested its usefulness using in vitro MOCK circulatory system. To notice a natural heart's Pumping status, electrocardiogram(ECG) signal was used and as a result of test. the counterpulsation effect between YAD and a natural heart was occurred and Automatic Control Mode Transition was occurred properly.