• Journal of Families and Better Life
• /
• 제30권3호
• /
• pp.69-82
• /
• 2012

The purpose of this study was to investigate the degree of sexual behavior. In particular, this study focused on the self-esteem, internet pornography addiction, and relationship satisfaction of freshmen as important predictors of sexual behavior and examined the dynamics of the relationships among the variables. The participants in this research were 1,806 university freshmen: 932 males and 828 females. All respondents submitted their answers on a self-report questionnaire. The data were analyzed with descriptive statistics and Pearson's correlations that used PASW 18.0, and AMOS 18.0, a statistical program for structural equation modeling(SEM), to estimate the hypothesized structural equation model. The major results of this study were as follows: (1) Relationship satisfactions mediated the relationships among self-esteem, internet pornography addiction, and sexual behavior. (2) Sexual behavior between male and female freshmen showed different influences on the test of the structural model invariance across the groups.

• Structural Engineering and Mechanics
• /
• 제67권6호
• /
• pp.565-578
• /
• 2018

This research article reported the nonlinear finite solutions of the nonlinear flexural strength and stress behaviour of nano sandwich graded structural shell panel under the combined thermomechanical loading. The nanotube sandwich structural model is derived mathematically using the higher-order displacement polynomial including the full geometrical nonlinear strain-displacement equations via Green-Lagrange relations. The face sheets of the sandwich panel are assumed to be carbon nanotube-reinforced polymer composite with temperature dependent material properties. Additionally, the numerical model included different types of nanotube distribution patterns for the sandwich face sheets for the sake of variable strength. The required equilibrium equation of the graded carbon nanotube sandwich structural panel is derived by minimizing the total potential energy expression. The energy expression is further solved to obtain the deflection values (linear and nonlinear) via the direct iterative method in conjunction with finite element steps. A computer code is prepared (MATLAB environment) based on the current higher-order nonlinear model for the numerical analysis purpose. The stability of the numerical solution and the validity are verified by comparing the published deflection and stress values. Finally, the nonlinear model is utilized to explore the deflection and the stresses of the nanotube-reinforced (volume fraction and distribution patterns of carbon nanotube) sandwich structure (different core to face thickness ratios) for the variable type of structural parameter (thickness ratio, aspect ratio, geometrical configurations, constraints at the edges and curvature ratio) and unlike temperature loading.

• The Korean Journal of Applied Statistics
• /
• 제30권6호
• /
• pp.827-849
• /
• 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
• /
• 제5권6호
• /
• pp.679-689
• /
• 1997

The damage of concrete subjected to multiaxial complex loading involves strong anisotropy due to its highly heterogeneous nature and the geometrically anisotropic characteristic of the microcracks. A comprehensive description of concrete damage is proposed by introducing a fourth-order anisotropic damage tenser. The evolution of damage is assumed to be related to the principal components of the current states of stress and damage. The unilateral effect of damage due to the closure and opening of microcracks is taken into account by introducing projection tensors that are also determined by the current state of stress. The proposed damage model considers the different kinds of damage mechanisms that result in different failure modes and different patterns of microdefects that cause different unilateral effects. This damage model is embedded in a thermomechanically consistent constitutive equation in which hardening and the triaxial compression caused shear-enhanced compaction can also be taken into account. The validity of the proposed model is verified by comparing theoretical and experimental results of plain and steel fiber reinforced concrete subjected to complex triaxial stress histories.

• Structural Engineering and Mechanics
• /
• 제63권2호
• /
• pp.251-257
• /
• 2017

A local damage identification method using measured structural static displacement is proposed in this study. Based on the residual force vector deduced from the static equilibrium equation, residual strain energy (RSE) is introduced, which can localize the damage in the element level. In the case of all the nodal displacements are used, the RSE can localize the true location of damage, while incomplete displacement measurements are used, some suspicious damaged elements can be found. A model updating method based on static displacement response sensitivity analysis is further utilized for accurate identification of damage location and extent. The proposed method is verified by two numerical examples. The results indicate that the proposed method is efficient for damage identification. The advantage of the proposed method is that only limited static displacement measurements are needed in the identification, thus it is easy for engineering application.

• Korean Journal of Child Studies
• /
• 제33권1호
• /
• pp.81-92
• /
• 2012

The main purpose of this study was to analysis of the structural relationship between early adolescents' social relationships, self esteem, life satisfaction, and school adjustment. Data harvested from the Korean Youth Panel Survey 2010 was analyzed by means of Structural Equation Modeling (SEM). The results indicate that the model is appropriate in terms of goodness of fit and significant path based on the validation procedure. According to the model, the social relationships have some degree of influence upon self esteem which then goes on to have a subsequent effect on life satisfaction; which in turn have a further influence on school adjustment. Social relationships also have a direct influence on life satisfaction, school adjustment, and self esteem has a direct influence on school adjustment. The paper concludes with an outline of the implications of the present study for future studies on this subject.

• Structural Engineering and Mechanics
• /
• 제18권6호
• /
• pp.709-729
• /
• 2004

This paper presents numerical and experimental investigations on damage detection of mono-coupled multistory buildings using natural frequency as only diagnostic parameter. Frequency equation of a mono-coupled multistory building is first derived using the transfer matrix method. Closed-form sensitivity equation is established to relate the relative change in the stiffness of each story to the relative changes in the natural frequencies of the building. Damage detection is then performed using the sensitivity equation with its special features and minimizing the norm of an objective function with an inequality constraint. Numerical and experimental investigations are finally conducted on a mono-coupled 3-story building model as an application of the proposed algorithm, in which the influence of modeling error on the degree of accuracy of damage detection is discussed. A mono-coupled 10-story building is further used to examine the capability of the proposed algorithm against measurement noise and incomplete measured natural frequencies. The results obtained demonstrate that changes in story stiffness can be satisfactorily detected, located, and quantified if all sensitive natural frequencies to damaged stories are available. The proposed damage detection algorithm is not sensitive to measurement noise and modeling error.

• Structural Engineering and Mechanics
• /
• 제83권6호
• /
• pp.729-744
• /
• 2022

In this paper, an analytical formulation is proposed to predict the vertical vibration response due to the pedestrian walking on a footbridge considering the human-structure interaction, where the footbridge and pedestrian are represented by the Euler beam and linear oscillator model, respectively. The derived coupled equation of motion is a nonlinear fourth-order partial differential equation. An uncoupled solution strategy based on the combined weighted residual and perturbation method) is proposed to reduce the tedious computation, which allows the separate integration between the bridge and pedestrian subsystems. The theoretical study demonstrates that the pedestrian subsystem can be treated as a structural system with added mass, damping, and stiffness. The analysis procedure is then applied to a case study under the conditions of single pedestrian and multi pedestrians, and the results are validated and compared numerically. For convenient vibration design of a footbridge, the simplified peak acceleration formula and the idea of decoupling problem are thus proposed.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• 제33권6호
• /
• pp.2483-2491
• /
• 2013

In order to identify and understand the crucial factors to induce traffic accident, causal relationships between diverse factors and traffic accident occurrence have been investigated continuously. It is one of most important issues all over the world to reduce the number of traffic accidents and deaths by them. Korea government is also stepping up their effort to reduce the number of traffic accidents and mitigate the severity of the accidents by establishing various traffic safety strategies. By introducing the five-day work week and increasing concern of leisure activities, the differences of trip characteristics between weekday and weekend is getting greater. According to this, the patterns and crucial factors of traffic accident occurrence in weekend appear differently from those in weekday. This study aims to understand major different factors affecting accident severity between weekday and weekend using 12,042 incident data occurred on freeways of Korea from 2006 to 2011. The model developed in this study estimated relationships among various exogenous factors of traffic accident by each type using SEM(Structural Equation Model). The result provides that road factors are related to the accident severity for weekday model, while environment factors affects on accident severity for weekend.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• 제20권2호
• /
• pp.289-297
• /
• 2020

The purpose of this study is to verify the effect of university students's innovativeness on adoption intention of academic convergence. For this objectives, the Structural Equation Model(SEM) was designed and analysed by using Lisrel. This study developed a research model, based upon TAM, to analyse the factors: personal innovativeness, social expectation, perceived usefulness and adoption intention of academic convergence. The main results are follows as: first, personal innovativeness showed a significant positive direct effect on adoption intention of academic convergence, and indirect effect through perceived usefulness on it. Second, through perceived usefulness, there was indirect effect between social expectation and adoption intention of academic convergence. The SEM in this study showed the statistical significance, which the model fit was χ²=22.638(df=29, p=.793). Based upon the result of analyses, the study suggested to develop the subject and non-subject educational program through which students experience innovativeness and usefulness for academic convergence. Especially, the change of the role and the task of the curriculum of liberal arts was.