• Journal of the Korean Magnetics Society
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• v.18 no.4
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• pp.127-130
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• 2008

We report a theoretical description of ferromagnetic vortex motion in sub-micrometer size magnetic thin film. Based on Thiele's equation combined with later theoretical achievements, we derive the analytic description of dynamics of ferromagnetic vortex core as a damped harmonic oscillatory motion. Consequently, the relations about frequency and damping constant in damped harmonic oscillation are presented. The validity of the results is verified through micromagnetic simulation.

• Korean Architects
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• no.3 s.97
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• pp.53-56
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• 1977

• The Korean Journal of Applied Statistics
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• v.27 no.7
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• pp.1187-1196
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• 2014

Italian Ryegrass (IRG), which is known as high yielding and the highest quality winter annual forage crop, is grown in mid-south area in Korea. This study aims to analyze the cause-and-effect relationship between IRG yield and climate variables such as temperature and precipitation by using IRG data and climate data of Korea Weather Bureau. From path analysis of structural equation model under multivariate normality, we found that there was a weather effect on IRG yield that the winter grass IRG yield was directly affected by spring temperature and indirectly affected by spring rainfall. These results showed that IRG can be sown in early spring in the area where it is hard to prepare for winter due to low temperature. This paper can contribute to increase IRG yield by showing the cause-and-effect relationship and this study can be extended to various structural equation models for other crops.

• Journal of the Earthquake Engineering Society of Korea
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• v.5 no.6
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• pp.55-64
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• 2001

Industrial machines are sometimes exposed to the danger of earthquake. In the design of a mechanical system, this factor should be accounted for from the viewpoint of reliability to analyze a complex nonlinear structure system under random excitation is proposed. First, the actual random excitation, such as earthquake, is approximated to the corresponding Gaussian process for the statistical analysis. The modal equations of overall system are expanded sequentially. Then, the perturbed equations are synthesized into the overall system and solved in probabilistic way. Several statistical properties of a random process that are of interest in random vibration are evaluated in each substructure. Comparing with the results of the numerical simulation proved the efficiency of the proposed method.

• Journal of Internet Computing and Services
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• v.15 no.6
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• pp.77-84
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• 2014

The purpose of this study is to explore factors affecting the effect of e-learning, and to find out the casual relationship among these factors. Subjects are 2,091 students who have participated in e-learning based class during the period of second semester in 2013. Those of them, 1,732 students response to the survey questions. After gathering data, they are analyzed by using Confirmative Factor Analysis and Structural Equation Modeling. From the result of Confirmative Factor analysis, data have reduced four factors, and are named as four latent variables likes e-learning effect, contents satisfaction, managing assistant factor, and system functional factor. From the result of Structural Equation Modeling, it is known as the relation and impact among factors: (a) "managing assistant factor" affects to "contents satisfaction" directly. (b) "contents satisfaction" affects to "e-learning effect" directly. (c) "system function factor" affects directly to "contents satisfaction", but does not affect directly to "e-learning effect". (d) both "managing assistant factor" and "system function factor" have an indirect effect on "e-learning effect" via "contents satisfaction".

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.2
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• pp.295-302
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• 2018

Since the history of the South Korea roundabouts is short, there is a possibility that drivers' awareness for the roundabouts (rules of the road, definition, location, etc.) is low, which may affect the compliance with traffic rules. Based on this assumption, the objective of this study is to analyze the relationship between the awareness and the compliance of traffic rules for roundabouts using a structural equation modeling (SEM). To carry out this objective, an online survey was conducted for 526 drivers, who reside in Goyang, Korea, and an SEM was estimated based on the survey data. As a result, it is concluded that awareness of roundabout has a positive impact on the compliance of traffic rules. Additionally, the compliance is found to show a positive relationship with driving experience. Based on the analysis results, an affective approach through soft measures such as awareness campaigns and educations is recommended to effectively address and mitigate the negative issues induced by roundabouts.

• The Korean Journal of Applied Statistics
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• v.30 no.6
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• pp.901-916
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• 2017

Recently, the industrial paradigm shift to the fourth industry has already begun, and the importance of patents as intangible intellectual property in the fourth industry era is increasing day by day. Since the technical valuation of a patent is calculated according to the opinion of experts, it is costly and time consuming, and hence, the quality of the patent is judged based on subjective opinions of non-experts. Therefore, it is necessary to develop an objective and rational evaluation system for the qualitative level of patents. In this paper, we classify the valuation of patents into technicality, rights, and usability, and consider the quantitative and objective evaluation modeling of patents using Bayesian structural equation model. In particular, based on the data collected by the Korea Invention Promotion Association, we apply the Bayesian approach, which is capable of stable modeling even under small samples by using prior information, and the structural equation model, which is excellent for modeling and evaluating qualitative performance that is difficult to measure directly, to develop a patent evaluation model.

• Journal of Digital Convergence
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• v.14 no.6
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• pp.167-175
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• 2016

This study analyzed empirically the same data through SPSS statistic(regression analysis) and AMOS program(structural equation model) used for cause and effect analysis. The result of empirical analysis was as follows. The different outcome of coefficients and p-values were deducted. Especially, in the mediated effect testing, meanwhile, SPSS statistic(regression analysis) pictured mediated effect, AMOS program(structural equation model) did not picture mediated effect on the reject zone of null hypothesis(absolute t-value and C.R.-value were nearby 1.96). Eventually, this study showed that what program used determined the outcomes of coefficients and p-values(In particular, the outcomes were differentiated further in the increasing measurement error) though using the same data.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.3
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• pp.463-469
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• 2002

The governing equation and force-displacement rotations of a beam-column element on elastic foundation we derived based on variational approach of total potential energy. An exact static and dynamic 4×4 element stiffness matrix of the beam-column element is established via a generalized lineal-eigenvalue problem by introducing 4 displacement parameters and a system of linear algebraic equations with complex matrices. The structure stiffness matrix is established by the conventional direct stiffness method. In addition the F. E. procedure is presented by using Hermitian polynomials as shape function and evaluating the corresponding elastic and geometric stiffness and the mass matrix. In order to verify the efficiency and accuracy of the beam-column element using exact dynamic stiffness matrix, buckling loads and natural frequencies are calculated for the continuous beam structures and the results are compared with F E. solutions.

• Journal of Digital Convergence
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• v.15 no.2
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• pp.89-98
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• 2017

This study analyzed empirically the same data through SPSS statistics(regression analysis) and AMOS program(structural equation model) used for cause and effect analysis. The result of empirical analysis of moderation effect was as follows. Meanwhile, SPSS statistics(regression analysis) did not pictured moderation effect in the categorical data(sex) and continous data(satisfaction of consunting), AMOS program(structural equation model) pictured partial moderation effect about the effecting of consultant's capability and attitude on the consulting repurchase within 10% level of significant. Eventually, This study showed that AMOS program and SPSS statistics used different methology in moderation effect, thus the different outcomes appeared although using the same data.