• Proceedings of the KSME Conference
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• 2001.06c
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• pp.275-280
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• 2001

Seismic isolator system is one of the most widely used base isolation system in order to control the vibration of structure against earthquake excitation. The evaluation of vulcanization time in molding the rubber bearing is very important for both proper ability of isolator and efficiency of manufacture. This paper deals with experimental measurement of temperature of isolator with senor inside in it, and compared with the result of FEA in order to evaluate the vulcanization time. Properties of rubber bearing which is used in the FEA are obtained by controlling the specific heat of rubber. With the obtained properties of rubber, the isolator is analysed by FEA. As a result, an appropriate analytical vulcanization time is obtained. This time is regarded as an appropriate temperature, which is used to effective manufacture.

• Journal of the Korean Society for Library and Information Science
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• v.9
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• pp.99-118
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• 1982

This paper first reviews various techniques proposed for automatic indexing with special emphasis placed on statistical techniques. Frequency-based statistical techniques are categorized into the following three approaches for further investigation on the basis of index term selection criteria: term frequency approach, document frequency approach, and probabilistic approach. In the experimental part of this study, Pao's technique based on the Goffman's transition region formula and Harter's 2-Poisson distribution model with a measure of the potential effectiveness of index term were tested. Experimental document collection consists of 30 agriculture-related documents written in Korean. Pao's technique did not yield good result presumably due to the difference in word usage between Korean and English. However, Harter's model holds some promise for Korean document indexing because the evaluation result from this experiment was similar to that of the Harter's.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.750-753
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• 2005

An equivalent linearization technique based on Rayleigh peak distribution for friction damper and brace system (FDBS) under stochastic excitation is proposed. For verification, shaking table test of a small scale 3-story building model with the FDBS is conducted for various slip moment levels. Using experimental result, equivalent linearization of the FDBS is conducted based on Rayleigh peak distribution, which is compared with measured peak distribution. For comparative study, model updating technique is applied based on identified modal properties. Finally, complex modal analysis and time history analysis for the obtained equivalent linear systems are conducted and compared with experimental result

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.802-805
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• 2007

The exhaust system, including a muffler, is one of the major sources to generate the radiated noise of construction equipment. The muffler is generally known that it reduces the exhaust noise level, but it sometimes increases the noise level because of the flow effect inside a muffler. So, it is required to consider the flow effect inside a muffler to reduce the exhaust noise level of construction equipment. In this paper, an experimental method to consider a quantitative flow effect inside a muffler was set up through a series of tests. Finally, the experimental result was verified through the flow noise analysis using CFD analysis result. These results make it possible to understand the dynamic characteristics of the flow noise and to design the low noise muffler for the construction equipment.

• Proceedings of the KSPS conference
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• 2004.05a
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• pp.251-255
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• 2004

The purpose of this paper is to examine the effect of using songs for the acquisition of English Prosody in elementary school. For the purpose, 8 classes were chosen to teach songs for four months, and listening tests and reading test were performed for analyzing the effect. The result is as follows : (1) The result of listening test showed that the average scores of the experimental classes were higher than those of comparative classes, and it was more effective in lower grades than in upper grades. (2) In pronunciation tests, the pronunciations of experimental classes were more similar to native speaker's pronunciation that those of comparative classes in intonation, lexical stress and sentence stress. (3) Singing songs repeatedly is more important than learning many songs. It means that to give the chances to sing as many times as possible is advisable for teaching pronunciation.

• Tribology and Lubricants
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• v.20 no.4
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• pp.183-189
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• 2004

The floating ring seal is used in an oxidizer and a fuel pump of the turbo pump unit in the liquid rocket engine to optimize a leakage without rubbing phenomenon. The damper floating ring seal, one of the floating ring seals, is with round hole pattern surfaces. It can reduce the leakage by increased friction factor that obtained from experimental data. In this paper, the leakage test about floating ring seal and damper floating ring seal was conducted. The test result showed the leakage performance of damper floating ring seal was better than the leakage performance of floating ring seal. With the leakage test the lock-up and rotation test about seal was conducted and that position is measured. The relatively large lock-up eccentric ratio was obtained from the test result of damping floating ring seal. The attitude angle of seal increases with increasing of shaft rotation.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.116-119
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• 2003

In this study, to achieve the optimal conditions for mechanical hyper-fine pattern fabrication process, deformation behavior of the materials during indentation was studied with numerical method by ABAQUS S/W. Brittle materials (Si, Pyrex glass) were used as specimens, and forming conditions to reduce the elastic restoration and pile-up was proposed. The indenter was modeled a rigid surface. Minimum mesh sizes of specimens are 1-10nm Comparison between the experimental data and numerical result demonstrated that the finite element approach is capable of reproducing the loading-unloading behavior of a nanoindentation test. The result of the investigation will be applied to the fabrication of the hyper-fine pattern.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1996.10a
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• pp.23-28
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• 1996

RUBBER JOINER, developed by using rubber and chains in combination. It is already applied to many practical use. In this paper, we would like to introduce experimental result about RUBBER JOINER while developing process. And, in recent years, effect of impulsive tension reducing is certified by experiment. We would like to mention the experimental result, too. (omitted)

• Proceedings of the Korea Concrete Institute Conference
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• 1995.04a
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• pp.148-153
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• 1995

In this report, the physical and chemical properties of Che-ju aggregates were stedued, and the properties of concrete using 5 types combinations of Che-ju aggreagtes were compared with those of concrete using Dag-jeon area aggreagtes. As a result of the properties of Che-ju aggregates are very different with Dae-jeon area aggregates in many aspects. Especially, entrained air content of aggregate is over 1.5% so that the freezing & thawing resistance of concrete was caused in decrease. And the texture properties of Che-ju aggregates and a little content of the entrained air in mortar increase bonding stress between mortar and aggregate, as a result in improving the compressive strength of concrete. Meanwhile, the relationship between cement water ratio(C/W) and 28days compressive strength of concrete(F28) is derived from the stastical regression using experimental data as $F_{28} = -99 + 276 *($(C/W), so this eqation is useful for mix-design of concrete in Che-ju area.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.05a
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• pp.220-224
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• 2002

In this paper, flow in the wake region of a butterfly valve is studied numerically and experimentally. The disk angle of the valve is fixed as $30^{\circ}$ and the free stream velocity as 0.13m/s in the experiment. Numerical analysis is performed in similitude of the experiment. The standard LES model is used to represent the turbulence effect in the commercial code Fluent 5.5. It is shown that the numerical result is similar to the experimental result for the wake flow of a butterfly-type valve.