• Journal of the Korean Society for Advanced Composite Structures
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• v.7 no.1
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• pp.1-8
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• 2016

In this paper, the full-size structural performance test for a lightweight soundproof tunnel composed of partitioned pipe truss members is carried out to investigate the structural performance. In addition, a nonlinear structural analysis of the same finite element model as the full-size testing model is performed to compare the test result. The test and analysis results showed that the lightweight soundproof tunnel ensures the structural safety against wind loads, snow loads and load combinations. As a result, the full-size test and analysis results meet all the design load conditions, hence the proposed lightweight soundproof tunnel is ready for the field application.

• International Commerce and Information Review
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• v.12 no.1
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• pp.153-175
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• 2010

This study conducts an analysis to verify an existence of co-movement among the exchange rates of Yuan-Dollar, Yen-Dollar and Won-Dollar by using time series data. An analysis period is divided into two periods. Therefore the first analysis period is from Dec. 17, 1997 to Jul. 21th. 20, 2005 and the second analysis period is from Jul. 25th, 2005 to Nov. 20th. 2009. This paper uses VAR model and daily data of exchange rates during the period. According to the result of an empirical analysis, yuan-dollar exchange rate has affected by th other variables ; yen-dollar exchange rate. It can be proved by result of an impulse response test and variance decomposition test in the second period. Therefore the won-dollar, yen-dollar, and Yen-dollar exchange rate has been influenced each other and the relationship will be maintained.

• Journal of the Korean Society of Earth Science Education
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• v.8 no.3
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• pp.259-266
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• 2015

This study aims to analyze a selective examination for the gifted and talented from a domain-general and special standpoint. For this, we analyzed gifted and talented test results carried out by Gifted and Talented Education institute affiliated with the university of Education located in the central region of South Korea. This test consisted of three sections which are giftedness in the first round, academic aptitude in the second round and interview in the last round. I conducted the analysis of variance of the giftedness test result to the gifted and talented group in each subject from the domain-general point of view. As a result, the each group was not significant. This means that the gifted and talented in each subject has giftedness from the domain-general viewpoint. Secondly, I implemented the analysis of correlation among three test such as giftedness, academic aptitude and interview conducted during the selective process for the gifted and talented. The result was that they had a low or no correlations between them and were not significant. This demonstrated that each test checked a different area. That is, we came to realize that the first, second and third test evaluates a different area and in particular, with the result that the first and second test had a low or no correlations between both of them we realized that they evaluated a different area from a domain-special standpoint. The purpose of this study is meaningful to investigate in terms of how the selective test for the gifted and talented is conducted from a domain-general and special standpoint as a recent study viewpoint about the gifted and talented along with creativity. It is too limited to generalize this result because this test was sampled by one region but, this study indicates that we should take a domain-general and special standpoint into account when it comes to selection for the gifted and talented.

• Journal of the Korean Geotechnical Society
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• v.22 no.7
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• pp.5-12
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• 2006

In this study, 2D shallow tunnel model test using close range photogrammetric technique was conducted with aluminium rods simulating continuum granular material. Numerical analysis was also carried out in order to identify the behaviour of subsurface deformations caused by shallow tunnelling. Direction and magnitude of displacement vectors from the model test were identical to the result of numerical analysis based on the model data. In particular, it is shown that the vector direction was toward a point below the tunnel invert level. A narrow "chimney or tulip like" pattern of vertical displacement was confirmed by both the model test and numerical analysis. This behaviour is consistent with the field data. In addition to the qualitative comparison, the quantitative result of subsurface settlements according to 2D volume loss showed good agreement between the model test and numerical analysis. Therefore, close range photogrammetric technique applied in the model test may be used to validate the result from the continuum numerical analysis.

• Aerospace Engineering and Technology
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• v.5 no.2
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• pp.77-84
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• 2006

We should measure receiver tracking threshold and command threshold of the satellite in Integrate System Test (IST) in order to check the normal received power range of LEO(Low Earth Orbit) satellite S-band receiver. In this paper, the algorithm of threshold measurement is examined and the result measured in Integrated System Test is displayed. And than, the factor could have an effect on the result of threshold measurement except the capability of receiver itself was analyzed and compensated as many as distorted value according to that analysis.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.5
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• pp.830-835
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• 2012

A research for application of LDSMC(Low Density Sheet Molding Compound) composite is in progress for lightening the weight. This paper has performed fatigue test and simulation of external panel for Korean commercial vehicle. Before the fatigue test, static test was carried out. From the test, the structural safety was investigated using Goodman diagram. After the static test performance, the fatigue test was conducted at a range of load frequency 5Hz, a stress ratio(R) of 0.05 and an endurance limit of $10^6$ to obtain the S-N curve. The S-N curve is applied to the fatigue analysis of the external panel assembly. The result of FEM analysis was in accord with the experimental result within 83% confidence. It showed that the process to set up the safety range of allowable error is required in process of the design and simulation verification.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.15-18
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• 2008

This study fulfilled analysis of startup characteristics of Turbo pump unit-Gas generator open loop test from the viewpoint of simulation. The test results were investigated and the calculated results were compared to test results. The curve for RPM developing predicted by simulation agreed well with test result. The slope of transient combustion pressure of gas generator correspond with test result.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.19-22
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• 2008

This study fulfilled analysis of startup characteristics of Turbo pump unit-Gas generator closed loop test from the viewpoint of simulation. The test results were investigated and the calculated results were compared to test results. The curve for RPM developing predicted by simulation agreed well with test result. The slope of transient combustion pressure of gas generator correspond with test result.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.595-600
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• 2009

Passengers in a vehicle feel uncomfortable due to squeal noise. Squeal noise, a kind of self-excited vibration, is generated by the friction force between the disc and the pad of the automobile. In this paper, modal analysis of wheel brake system was performed in order to prediction of squeal phenomenon. It was shown that the prediction of system instability is possible by FEM. Finite element model of that brake system was made. Some parts of a real brake was selected and modeled. The normal mode analysis method performs analyses of each brake system component. Experiment of modal analysis was performed for each brake components and experimental results were compared with analytical result from FEM. The complex eigenvalue analysis results compared with braking test. The analysis results show good correlation with braking test for the squeal frequency at an unstable mode.

• Journal of Applied Reliability
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• v.16 no.4
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• pp.323-330
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• 2016

Purpose: Recently, propensity score matching method is used in a large number of research paper, nonetheless, there is no research using fitness test of before and after propensity score matching. Therefore, comparing fitness of before and after propensity score matching by logistic regression analysis using data from 'online survey of adolescent health' is the main significance of this research. Method: Data that has similar propensity in two groups is extracted by using propensity score matching then implement logistic regression analysis on before and after matching separately. Results: To test fitness of logistic regression analysis model, we use Model summary, -2Log Likelihood and Hosmer-Lomeshow methods. As a result, it is confirmed that the data after matching is more suitable for logistic regression analysis than data before matching. Conclusion: Therefore, better result which has appropriate fitness will be shown by using propensity score matching shows better result which has better fitness.