• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1A
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• pp.19-30
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• 2012

Recently, vision-based dynamic deflection measurement techniques have significant interests and are getting more popular owing to development of the high-quality and low-price camcorder and also image processing algorithm. However, there are still several research issues to be improved including the self-vibration of vision device, i.e. camcorder, and the image processing algorithm in device aspect, and also the application area should be extended to measure three dimensional movement of floating structures in application aspect. In this study, vision-based dynamic motion measurement technique using multiple targets is proposed to measure three dimensional dynamic motion of floating structures. And also a new scheme to select threshold value to discriminate the background from the raw image containing targets. The proposed method is applied to measure the dynamic motion of large concrete floating quay in open sea area under several wave conditions, and the results are compared with the measurement results from conventional RTK-GPS(Real Time Kinematics-Global Positioning System) and MRU(Motion Reference Unit).

• Management & Information Systems Review
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• v.38 no.3
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• pp.113-125
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• 2019

This study empirically analyzes the effect of SNS informativeness, playfulness and reliability on purchase intention and the effect of consumer's purchase intention on business performance through structural equation model, In doing so, this study aims to suggest ways to enhance consumers' purchase intention and consequently increase the business performance through various SNS marketing strategies that can efficiently manage consumers. The questionnaires were distributed to adult men and women who are in their 20s through 60s, actively use SNS, and primarily reside in Daegu and Gyeongbukdo. The 400 copies of questionnaire were distributed from September 15 to October 1, 2018, of which 364 (91%) were used for the empirical analysis, except for 36 of the questionnaires that were unfaithful or unresponsive. Basic statistical analysis including frequency analysis was performed using SPSS 22.0 and AMOS 24.0, reliability and validity analysis were also performed, and finally hypotheses were tested by performing confirmatory factor analysis and path analysis of structural equation model. All of the SNS informativeness, playfulness and reliability were shown to have positive effects on the purchase intention. In addition, the effect of purchase intention on business performance was found to be significant. Companies should come up with a strategic SNS marketing plan to encourage consumers to enhance the willingness to purchase their products and services through SNS, and to make actual purchases, thereby improving business performance.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.1
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• pp.1-8
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• 2014

Using the level set and the meshfree methods, we develop a topological shape optimization method applied to linear elasticity problems. Design gradients are computed using an efficient adjoint design sensitivity analysis(DSA) method. The boundaries are represented by an implicit moving boundary(IMB) embedded in the level set function obtainable from the "Hamilton-Jacobi type" equation with the "Up-wind scheme". Then, using the implicit function, explicit boundaries are generated to obtain the response and sensitivity of the structures. Global nodal shape function derived on a basis of the reproducing kernel(RK) method is employed to discretize the displacement field in the governing continuum equation. Thus, the material points can be located everywhere in the continuum domain, which enables to generate the explicit boundaries and leads to a precise design result. The developed method defines a Lagrangian functional for the constrained optimization. It minimizes the compliance, satisfying the constraint of allowable volume through the variations of boundary. During the optimization, the velocity to integrate the Hamilton-Jacobi equation is obtained from the optimality condition for the Lagrangian functional. Compared with the conventional shape optimization method, the developed one can easily represent the topological shape variations.

• Journal of Industrial Convergence
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• v.21 no.4
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• pp.133-143
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• 2023

The purpose of this study is to verify the mediating effect of depression on the effect of forest recreation satisfaction on psychological well-being of customers using forest recreation resources and provide basic data for improving psychological well-being. As for the analysis data, a survey was conducted on 450 customers using forest recreation resources, and the final 355 people were selected as subjects of the survey after removing non-response and insincere responses from 377 copies collected. For analysis, the SPSS WIN 23.0 and Amos 21.0 programs were used, and the mediating effect of depression was verified through descriptive statistical analysis, correlation analysis, and structural model of major variables. The study results showed, first, that forest recreation satisfaction had a negative(-) effect on depression. Second, depression was found to have a negative(-) effect on psychological well-being. Third, depression had a complete mediating effect in the relationship between forest recreation satisfaction and psychological well-being. Based on these results, it is meaningful in that programs and practical and policy suggestions were made to improve psychological well-being.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.215-222
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• 2015

The purpose of this study was to examine the relationship among physical self-concept, leisure sport participation satisfaction, and leisure sport participation level. By analysing a total of 353 university students participating in leisure sport with structural equation modeling through AMOS 20.0 statistics program, this study found the followings. First, the physical self-concept has a positive influence on leisure sport participation satisfaction. Second, leisure sport participation level has a positive influence on leisure sport participation satisfaction. Third, there was no significant mediating effect of leisure sport participation level on the relationship between physical self-concept and leisure sport participation satisfaction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.12
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• pp.7101-7109
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• 2014

This study examined the relationship among self-control, physical activity, Internet addiction, cyber ethnics, and cyber delinquency. The data from a total of 388 adolescent girls was analyzed by structural equation modeling using the AMOS 20.0 statistics program. First, the level of physical activity affects Internet addiction mediated by self-control. Second, self-control affects Internet addiction and cyber ethnics directly and has an influence on the cyber delinquency mediated by Internet addiction. Third, Internet addiction has direct effects both cyber delinquency and cyber ethnics.

• Journal of Navigation and Port Research
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• v.27 no.1
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• pp.63-70
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• 2003

If semi-rigid connections are used for superstructures of very large floating structures (VLFS), the number of rigid connections can be reduced and more economical construction will be possible. In this study, considering service load and wave load in VLFS, the applicability of mixed use of rigid and semi-rigid connections have been studied using three types of connections for a four-bay eight-story frame. Three types of connections are used; top and seat-angle connections with double web-angle(TSD), extended end plate connections, steel tubular column with square external-diaphragm connections. ABAQUS(Finite element analysis program) is used for conducting second order elastic analysis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.4
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• pp.651-660
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• 2008

The widespread use of public networks, such as the Internet, for the exchange of sensitive data that need a severe security, like legally valid documents and business transactions. At the same time public-key certificates used for sensitive data interchange form the viewpoint of data integrity and authentication. But there are some weakness of data transfer capacity and security in public key infrastructure(PKI) environment. This paper use the RSA one-way accumulator to realize an efficient and dynamic authenticated dictionary, where untrusted directories provide cryptographically verifiable answers to membership queries on a set maintained by a trusted source.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5198-5206
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• 2015

The purpose of this study was to examine the effect of social support from friend, senior junior, and coach on student-athletes' stress and deviant behavior. By using convenience sampling method of non-probability sampling, a total of 350 student-athletes from D and G city were selected. Of 217 copies of the questionnaire gathered, 35 were discarded owing to having excessive missing values. Thus, by analysing a total of 182 surveys with structural equation modeling through AMOS 20.0 statistics program, this study found the followings. First, social support has a negative influence on stress. Second, stress has a positive influence on deviant behavior. Third, social support has a negative influence on deviant behavior mediated by stress.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.6
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• pp.359-366
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• 2020

In this study, a simulation-based damage estimation method for helidecks is proposed using an artificial neural network. The structural members that share a connecting node in the helideck are regarded as a damage group, and a total of 37,400 damage scenarios are numerically generated by applying randomly assigned damage to up to three damage groups. Modal analysis is then performed for all the damage scenarios, which are selectively used as either training or validation or verification sets based on the purpose of use. An artificial neural network with three hidden layers is constructed using a PyTorch program to recognize the patterns of the modal responses of the helideck model under both damaged and undamaged states, and the network is successively trained to minimize the loss function. Finally, the estimated damage rate from the proposed artificial neural network is compared to the actual assigned damage rate using 400 verification scenarios to show that the neural network is able to estimate the location and amount of structural damage precisely.