• Structural Engineering and Mechanics
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• v.38 no.1
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• pp.65-79
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• 2011

Concrete hydraulic structures such as: Dams, Intake Towers, Piers and dock are usually recognized as" Vital and Special Structures" that must have sufficient safety margin at critical conditions like when earthquake occurred as same as normal servicing time. Hence, to evaluate hydrodynamic pressures generated due to seismic forces and Fluid-Structure Interaction (FSI); introduction to fluid-structure domains and interaction between them are inevitable. For this purpose, first step is exact modeling of water-structure and their interaction conditions. In this paper, the basic equation involved the water-structure-foundation interaction and the effective factors are explained briefly for concrete hydraulic structure types. The finite element modeling of two concrete gravity dams with 5 m, 150 m height, reservoir water and foundation bed rock is idealized and then the effects of fluid domain and bed rock have been investigated on modal characteristic of dams. The analytical results obtained from numerical studies and modal analysis show that the accurate modeling of dam-reservoir-foundation and their interaction considerably affects the modal periods, mode shapes and modal hydrodynamic pressure distribution. The results show that the foundation bed rock modeling increases modal periods about 80%, where reservoir modeling changes modal shapes and increases the period of all modes up to 30%. Reservoir-dam-foundation interaction increases modal period from 30% to 100% for different cases.

• The Korean Journal of Applied Statistics
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• v.30 no.6
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• pp.827-849
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• 2017

Self-sufficiency (SS), which is often used in the social welfare policy of the American welfare system, is an important concept in the field of social welfare and has been studied so much. Among such studies there are also studies on how the employment hope scale and the perceived employment barrier scale, which the psychological SS (PSS) consists of, affect the economic SS (ESS) for low-income job seekers in the United States. These studies are generally conducted using survey data, which are mainly analyzed by structural equation model (SEM) in the field of social science field. In the survey data, the number of measurement variables is generally large and there is a correlation between variables. In such cases, Principal Component Analysis (PCA) can be used. The purpose of this study is to compare the results of SEM and PCA on the survey data mainly dealt with in the social science field. We compare the performance of the two analyzing methods through a small simulation study. We also analyze a real survey data of the ESS and the PSS by using these two methods and compare the results.

• Structural Engineering and Mechanics
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• v.43 no.2
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• pp.163-177
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• 2012

This paper presents a LMI(linear matrix inequality)-based fuzzy approach of modeling and active vibration control of geometrically nonlinear flexible plates with piezoelectric materials as actuators and sensors. The large-amplitude vibration characteristics and dynamic partial differential equation of a piezoelectric flexible rectangular thin plate structure are obtained by using generalized Fourier series and numerical integral. Takagi-Sugeno (T-S) fuzzy model is employed to approximate the nonlinear structural system, which combines the fuzzy inference rule with the local linear state space model. A robust fuzzy dynamic output feedback control law based on the T-S fuzzy model is designed by the parallel distributed compensation (PDC) technique, and stability analysis and disturbance rejection problems are guaranteed by LMI method. The simulation result shows that the fuzzy dynamic output feedback controller based on a two-rule T-S fuzzy model performs well, and the vibration of plate structure with geometrical nonlinearity is suppressed, which is less complex in computation and can be practically implemented.

• Structural Engineering and Mechanics
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• v.66 no.3
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• pp.329-341
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• 2018

This paper considers the smooth receding contact problem between a homogeneous half-plane and a composite laminate composed of an inhomogeneously coated elastic layer. The inhomogeneity of the elastic modulus of the coating is approximated by an exponential function along the thickness dimension. The three-component structure is pressed together by either a concentrated force or uniform pressures applied at the top surface of the composite laminate. Both semianalytical and finite element analysis are performed to solve for the extent of contact and the contact pressure. In the semianalytical formulation, Fourier integral transformation of governing equations and boundary conditions leads to a singular integral equation of Cauchy-type, which can be numerically integrated by Gauss-Chebyshev quadrature to a desired degree of accuracy. In the finite element modeling, the functionally graded coating is divided into homogeneous sublayers and the shear modulus of each sublayer is assigned at its lower boundary following the predefined exponential variation. In postprocessing, the stresses of any node belonging to sublayer interfaces are averaged over its surrounding elements. The results obtained from the semianalytical analysis are successfully validated against literature results and those of the finite element modeling. Extensive parametric studies suggest the practicability of optimizing the receding contact peak stress and the extent of contact in multilayered structures by the introduction of functionally graded coatings.

• Journal of the Korean Society of Clothing and Textiles
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• v.37 no.5
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• pp.631-644
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• 2013

This study investigates the gaps between ideal and actual corporate social responsibility (CSR) by comparing levels of CSR perceptions and examining the relationship differences between CSR perception, perceived quality, and affective trust from a consumer perspective. Data from 315 adult samples were collected through a nationwide online survey. In order to compare ideal and actual CSR, the study employed the approach of latent means analysis (LMA) and multi-group comparisons within the framework of a structural equation modeling (SEM). The result of latent means comparison showed significant differences of perceptions on fashion CSR across ideal and actual contexts. Only actual economic CSR was evaluated higher than in the ideal context and the effect size of inter-management CSR was the largest among seven domains. Multi-group SEM revealed a significant discrepancy between ideal and actual CSR structural models that exhibited relationships of CSR perception, perceived quality, and affective trust. The paths from internal management and ethical CSR to perceived quality and from economic and philanthropy CSR to affective trust were different across ideal and actual contexts. Implying the understanding of consumer CSR perceptions and the mediating role of perceived quality, this study suggests that marketers narrow the gap between ideal and actual CSR.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.4
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• pp.61-74
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• 2004

Risk analysis model is systematic and structural process that considers internal security problems and threat factors of the information systems to find optimal level of security control. But, the risk analysis model is just only defined conceptually and there are not so many empirical studies. This research used structural equation modeling(SEM) research methodology with rigorously validated research instrument. Based on results of this study, risk analysis methodology was proved to be practically useful in e-commerce environment. Factors like threat and control were significantly related to risk. In conclusion, the results of this study can be applied to general situation or environment of information security for analyzing and managing the risk and providing new approach to comprehend concept of risk in e-commerce environment.

• Culinary science and hospitality research
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• v.18 no.5
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• pp.146-164
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• 2012

This study aims to investigate the influence of person-organization(P-O) fit on job satisfaction, and turnover intent mediated through goal commitment using structural equation modeling. An experimental design is applied to test seven hypotheses that reflect the research questions. Five star deluxe hotel employees are targeted for sampling. A total of 180 faithful cases out of 250 cases have been analyzed. To analyze the data, descriptive statistics and multivariate analysis of variance, and structural equation modeling(SEM) are employed using SPSS 19.0 and AMOS 4. The results indicate the hotel employees' perceived P-O fit is positively associated with goal commitment and job satisfaction while negatively linked with turnover intent. Also, goal commitment has a positive effect on job satisfaction while having a negative effect on turnover intent, mediating between P-O fit and organizational outcomes. Therefore, the needs to evaluate P-O fit and goal commitment during recruitment and after organizational entry have been raised.

• Korean small business review
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• v.39 no.3
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• pp.57-76
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• 2017

While the unemployment rate is rising rapidly due to recent economic recession at home and abroad, university students' reluctance to apply for jobs in Small and Medium Enterprises (SME's) causes instability in manpower supply and demand and social unrest. To provide insights for solving the problem, this study explores how beliefs and attitudes of university students influence their intention to apply for jobs in SME's using Theory of Planned Behavior proposed by Icek Ajzen. This study followed the 2-stage survey methodology suggested by Ajzen. In the first stage of pilot study, a small sample of university students was used to illicit readily accessible behavioral outcomes, normative referents, and control factors. In the second stage of main study, the standard questionnaire was designed and administered and data were collected and analysed using the PLS Structural Equation Modeling (SEM) technique. PLS-SEM was used instead of Covariance Based (CB)- SEM considering the exploratory nature of this study. In overall, the results showed that TPB is very effective in explaining and predicting the university student's intention to apply for jobs in SEM's. Gender turned out to be a significant moderator variable in the relations between intention and its influence factors. Student's scholastic performance showed a negative correlation with intention. More research efforts need to be exerted to better understand university student's job seeking behavior.

• The Journal of the Korea Contents Association
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• v.18 no.3
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• pp.81-100
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• 2018

This study investigated the influential factor over the intention to buy autonomous driving car by applying extended technology acceptance model (TAM2). To this end, 117 ordinary persons experienced in driving car were analyzed by using SEM(Structural Equation Modeling). Analysis shows that the perceived usefulness and purchase intention is positively affected by social influence and recognized risk. It is found that perceived usefulness is not affected, but purchase intention is positively affected in the case of innovation. On the contrary, analysis shows that driving capability and car playfulness recognized by individual have no influence on the perceived easiness. Although the result that driving capability recognized by individual negatively affects perceived usefulness was not included in the study hypothesis, it was remarkable. Generalizing the above result, it is found that social influence, innovation and recognized risk as variables which affect the intention to buy autonomous car play the role of significant variable. This study is meaningful in that such result can foresee the perception of preliminary accommodators of new technology of the 4th industrial revolution, autonomous driving car.

• Journal of Korean Society for Quality Management
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• v.43 no.1
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• pp.11-30
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• 2015

Purpose: The purpose of this study is to lay groundwork for future research on the outcomes of national quality awards for secondary-care healthcare organizations. Methods: For this study, a secondary-care hospital was selected through a convenience sampling method and all of its organizational members participated in complete enumeration survey using 109 survey questions derived from the MBNQA criteria for healthcare through structural equation modeling (SEM) Results: As a result, Leadership was shown to drive Foundation and Direction, which affect System that creates Results with 12 hypotheses supported out of 18 hypotheses established. Conclusion: The findings of this study will provide valuable implications to the top management of secondary-care hospitals for self-examining quality management and promoting sustainable competitiveness.