• Steel and Composite Structures
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• v.1 no.4
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• pp.427-440
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• 2001

The growing use of unprotected or partially protected steelwork in buildings has caused a lively debate regarding the safety of this form of construction. A good deal of recent research has indicated that steel members have a substantial inherent ability to resist fire so that additional fire protection can be either reduced or eliminated completely. A performance based philosophy also extends the study into the effect of structural continuity and the performance of the whole structural totality. As part of the structural system, thermal expansion during the heating phase or contraction during the cooling phase in most beams is likely to be restrained by adjacent parts of the whole system or sub-frame assembly due to compartmentation. This has not been properly addressed before. This paper describes an experimental programme in which unprotected steel beams were tested under load while it is restrained between two columns and additional horizontal restraints with particular concern on the effect of catenary action in the beams when subjected to large deflection at very high temperature. This paper also presents a three-dimensional mathematical modelling, based on the finite element method, of the series of fire tests on the part-frame. The complete analysis starts with an evaluation of temperature distribution in the structure at various time levels. It is followed by a detail 3-D finite element analysis on its structural response as a result of the changing temperature distribution. The principal part of the analysis makes use of an existing finite element package FEAST. The effect of columns being fire-protected and the beam being axially restrained has been modelled adequately in terms of their thermal and structural responses. The consequence of the beam being restrained is that the axial force in the restrained beam starts as a compression, which increases gradually up to a point when the material has deteriorated to such a level that the beam deflects excessively. The axial compression force drops rapidly and changes into a tension force leading to a catenary action, which slows down the beam deflection from running away. Design engineers will be benefited with the consideration of the catenary action.

• Journal of Digital Convergence
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• v.19 no.5
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• pp.269-277
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• 2021

The purpose of the study is to explore the effect of university's managing and system support in online classes on learning participation mediated by learning presence and to examine the structural relationship between the factors. In order to achieve the purpose of the study, 135 students who take online "College English 2" classes were analyzed for the fitness of the research model and the path and structural analysis through a confirmative factor of the structural equation model. As a result of the study, first, the university's managing support for online class showed a positive effect to learning presence. Second, the university's managing support for online classes completely mediated learning presence and had a positive effect on learning participation. This study can clarify the structural relationship between environmental factors which are online class support and learners' characteristics in university online class, learning presence, and learning participation and can broaden the understanding of learning participation in online classes. It gives the implications that should be considered in teaching and learning design.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.2_2
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• pp.361-374
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• 2020

Recently, small and medium-sized rahmen-type bridges have been developed as a technology that ensures the stability of structural behavior and the safety of use at the same time by using efficient and economical materials that make up the convergence section of reinforced bar, structural steel and concrete. This study is about a rahmen-type structure applied with the installation and dismantling of the strut. It improves the serviceability of the structure by forming multi-points and efficiently applies the convergence section of structural steel and concrete materials to the structural system changes to induce the displacement improvement effect additionally. By constructing mock-up models for the beam-column joint, the displacement was calculated and compared, and this was compared and analyzed by numerical analysis. The final displacement showed an improvement effect of 13.46% to 36.28% based on the vertical displacement of the existing structure without struts through the experiment of the mock-up models. As a result of analysis by numerical analysis method, the displacement improvement effect of 42.89% could be derived.

• Journal of Families and Better Life
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• v.30 no.2
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• pp.75-86
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• 2012

The purpose of this study was to investigate the structural relationships school-aged children and related variables. For this study, the respondents were 704 children in elementary schools in the areas of Gyeongsan-Si and Daegu-Si. The questionnaires and psychological tests used in this study surveyed the following concepts: suicide ideation, social support, self-esteem and the scale of depression. The collected data were analyzed with AMOS 19.0, a statistical program for structural equation modeling, to estimate the hypothesized structural equation model. The results were as follows: First, self-esteem, - and depression as perceived by children were found to affect their suicide ideation directly. Second, parental support and teacher support as perceived by children were found to affect children's depression directly. Third, parental support, teacher support, and the support of friend's as perceived by children were found to affect-children's self-esteem directly. Last, parental support and, teacher's support did not show direct effect on children's suicide ideation, though these factors had an indirect effect on suicide ideation through the children's self-esteem and depression. Finally, teacher's support did not direct effectly children's suicide ideation, whereas it had an having indirect effect on suicide ideation through the children's self-esteem.

• Journal of Digital Convergence
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• v.9 no.4
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• pp.115-130
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• 2011

The purpose of this study is to examine the effect of career plateau(structural and content plateau) on IT service technical engineers' career satisfaction and career withdrawal intention. Survey data were collected from 161 IT service technical engineers. The results indicated that structural and content plateau were negatively related to career satisfaction, and content plateau was positively related to career withdrawal intention, but not structural plateau. In addition, the results of hierarchical multiple regressions indicated that content plateau had stronger effect on career satisfaction and career withdrawal intention then content plateau.

• Nuclear Engineering and Technology
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• v.49 no.1
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• pp.254-266
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• 2017

Finite-element analysis based on elastic-perfectly plastic material was conducted to examine the influence of structural deformations on collapse loads of circumferential through-wall critically cracked $90^{\circ}$ pipe bends undergoing in-plane closing bending and internal pressure. The critical crack is defined for a through-wall circumferential crack at the extrados with a subtended angle below which there is no weakening effect on collapse moment of elbows subjected to in-plane closing bending. Elliptical and semioval cross sections were postulated at the bend regions and compared. Twice-elastic-slope method was utilized to obtain the collapse loads. Structural deformations, namely, ovality and thinning, were each varied from 0% to 20% in steps of 5% and the normalized internal pressure was varied from 0.2 to 0.6. Results indicate that elliptic cross sections were suitable for pipe ratios 5 and 10, whereas for pipe ratio 20, semioval cross sections gave satisfactory solutions. The effect of ovality on collapse loads is significant, although it cancelled out at a certain value of applied internal pressure. Thinning had a negligible effect on collapse loads of bends with crack geometries considered.

• Smart Structures and Systems
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• v.18 no.3
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• pp.541-568
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• 2016

The goal of this study is to investigate the effect of non-synchronous sensing when using wireless sensors on structural identification and to attempt correcting such errors in order to obtain a better identification result. The sources causing non-synchronous sensing are discussed first and the magnitudes of such synchronization errors are estimated based on time stamps of data samples collected from Imote2 sensors; next the impact of synchronization errors on power spectral densities (PSDs) and correlation functions of output responses are derived analytically; finally a new method is proposed to correct such errors. In this correction method, the corrected PSDs of output responses are estimated using non-synchronous samples based on a modified FFT. The effect of synchronization errors in the measured output responses on structural identification and the application of this correction method are demonstrated using simulation examples. The simulation results show that even small synchronization errors in the output responses can distort the identified modal and stiffness parameters remarkably while the parameters identified using the proposed correction method can achieve high accuracy.

• International journal of advanced smart convergence
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• v.10 no.3
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• pp.172-180
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• 2021

The purpose of this study is to analyze the structural relationship among perfectionism and dance achievement of middle and high school students majoring in dance. Specifically, this study aims to investigate the effects of perfectionism on dance achievement through the medium of dance commitment and career decision-making self-efficacy. For this purpose, a structural equation model based on the previous studies was constructed with perfectionism as an exogenous variable and dance commitment, career decision-making self-efficacy, and dance achievement as endogenous variables. The final subjects of this study were 279 middle and high school students majoring in dance. The data were processed by frequency analysis to find out personal characteristics using SPSS 23 and exploratory factor analysis and reliability analysis were conducted on the research tools. In addition, AMOS 21 was used for confirmatory factor analysis, correlation analysis and structural equation model analysis. As a result of data processing on the research model. First, the sub-dimensions of perfectionism tendency 'worry about mistakes', 'personal standard', and 'doubt about behavior' had a statistically significant effect on dance commitment. Second, the sub-dimensions of perfectionism 'worry about mistakes', 'personal standard', and 'doubt about behavior' had statistically significant effects on career decision-making self-efficacy. Third, dance commitment did not have a statistically significant effect on dance achievement, but career decision-making self-efficacy had a statistically significant effect on dance achievement. These results provide implications.

• Structural Engineering and Mechanics
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• v.77 no.3
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• pp.369-381
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• 2021

The seismic responses of elevated tanks considering liquid-structure interaction are presented under horizontal earthquake. The scaled model tank is fabricated to study the dynamic responses of anchored tank and newly designed uplift tank with replaced dampers. The natural frequencies for structural mode are obtained by modal analysis. The dynamic responses of tanks are completed by finite element method, which are compared with the results from experiment. The displacement parallel and perpendicular to the excitation direction are both gained as well as structural acceleration. The strain of tank walls and the axial strain of columns are also obtained afterwards. The seismic responses of liquid storage tank can be calculated by the finite element model effectively and the results match well with the one measured by experiment. The aim is to provide a new type of tank system with vertical constraint relaxed which leads to lower stress level. With the liquid volume increasing, the structural fundamental frequency has a great reduction and the one of uplift tank are even smaller. Compared with anchored tank, the displacement of uplift tank is magnified, the strain for tank walls and columns parallel to excitation direction reduces obviously, while the one perpendicular to earthquake direction increases a lot, but the values are still small. The stress level of new tank seems to be more even due to uplift effect. The new type of tank can realize recoverable function by replacing dampers after earthquake.

• International journal of advanced smart convergence
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• v.10 no.2
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• pp.194-200
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• 2021

The purpose of this study is to analyze the structural relationship among self-leadership, grit, and performance.Specifically, self-leadership was selected as an independent variable, two dimensions of grit were selected as mediator variables, and performance was selected as a dependent variable. This structural equation model is based on previous studies.The subjects of this study were middle and high school Taekwondo players, and the survey was collected using the online survey system KSDC (Korean Social-Science Data Center). The sampling method was a non-probability sampling method, convenience sampling method.A total of 367 copies were collected through this process, and 355 copies were used as the final valid samples after excluding the insincere data.Data processing was done with SPSS 23 for frequency analysis, exploratory factor analysis and reliability analysis. Also, AMOS 21 was used for confirmatory factor analysis and structural equation model analysis. The results of the analysis are as follows: First, self-leadership had a positive effect on bothi interest consistency grit and effort persistence grit. Second, it was found that both interest consistency grit and effort persistence grit have a positive effect on performance.Third,self-leadership had a positive effect on performance.