• Fibers and Polymers
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• 제5권1호
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• pp.19-24
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• 2004

PET yarns textured at different texturing conditions were treated with superheated steam or dry heat at different temperatures for different times. The effects of the treatment conditions on the thermomechanical and structural changes of the yarn were examined by shrinkage, X-ray diffraction and birefringence measurements. With increase in superheated steam temperature, the crystalline orientation factor and birefringence decreased, whereas crystal size increased. Dry heat treatment had a smaller effect on shrinkage and structural properties in comparison with superheated steam treatment. The additional shrinkage after texturing process was investigated. The effect of heat-setting in both media was more significant at $200^{\circ}C$. The time dependence of the properties was not linear.

• Smart Structures and Systems
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• 제10권2호
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• pp.155-179
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• 2012

This paper aims at assessing the seismic performance of Tuned Mass Dampers (TMDs) based on sets of recorded ground motions. For the simplest configuration of a structure-TMD assembly, in a comprehensive study characteristic response quantities are derived and statistically evaluated. Optimal tuning of TMD parameters is discussed and evaluated. The response reduction by application of a TMD is quantified depending on the structural period, inherent damping of the stand-alone structure, and ratio of TMD mass to structural mass. The effect of detuning on the stroke of the TMD and on the structural response is assessed and quantified. It is verified that a TMD damping coefficient larger than the optimal one reduces the peak deflection of the TMD spring significantly, whereas the response reduction of the main structure remains almost unaffected. Analytical relations for quantifying the effect of a TMD are derived and subsequently evaluated. These relations allow the engineer in practice a fast and yet accurate assessment of the TMD performance.

• Structural Monitoring and Maintenance
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• 제4권1호
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• pp.53-68
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• 2017

The response sensitivity method in time domain has been applied extensively for damage identification. In this paper, the relationship between the error of damage identification and the sensitivity matrix is investigated through perturbation analysis. An index is defined according to the perturbation amplify effect and an optimal sensor placement method is proposed based on the minimization of that index. A sequential sub-optimal algorithm is presented which results in consistently good location selection. Numerical simulations with a two-dimensional high truss structure are conducted to validate the proposed method. Results reveal that the damage identification using the optimal sensor placement determined by the proposed method can identify multiple damages of the structure more accurately.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1991년도 봄 학술발표회 논문집
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• pp.72-78
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• 1991

An improved procedure for earthquake resistant design of multistory building structures is proposed in this study. The effect of gravity load on seismic response of structures is evaluated through nonlinear dynamic analyses of a single story example structure. The presence of gravity load tends to initiate plastic hinge formation in earlier stage of a strong earthquake. However, the effect of gravity load seems to disapper as ground motion is getting stronger. And one of shortcomings in current earthquake resistant codes is overestimation of gravity load effects when earthquake load is applied at the same time so that it may leads to less inelastic deformation or structural damage in upper stories, and inelastic deformation is increased in lower stories. Based on these observation, an improved procedure for earthquake resistant design is derived by reducing the factor for gravity load and inceasing that for seismic load. Structures designed by the proposed design procedure turned out to have increased safety and stability against strong earthquakes.

• Steel and Composite Structures
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• 제22권5호
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• pp.1141-1162
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• 2016

Concrete-filled double skin steel tube (CFDST) beam-columns are widely used in industrial plants, subways, high-rise buildings and arch bridges. The CFDST columns have the same advantages as traditional CFT members. Moreover, they have lighter weight, higher bending stiffness, better cyclic performance, and have higher fire resistance capacities than their CFT counterparts. The scope of this study is to develop finite element models that can predict accepted capacities of double skin concrete-filled tube columns under the combined effect of axial and bending actions. The analysis results were studied to determine the distribution of stresses among the different components and the effect of the concrete core on the outer and inner steel tube. The developed models are first verified against the available experimental data. Accordingly, an extensive parametric study was performed considering different key factors including load eccentricity, slenderness ratio, concrete compressive strength, and steel tube yield strength. The results of the performed parametric study are intended to supplement the experimental research and examine the accuracy of the available design formulas.

• 복식문화연구
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• 제16권6호
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• pp.1126-1141
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• 2008

The purposes of this study identify how attributes of the website impact on consumer attitude toward the website. For this purpose, the study tested covariance structural model which set relationships among independent variables (interactivity and shopping value), meditated variables(relationship commitment), and dependent variables(attitude toward website). The data were collected from a sample of 239 internet shopper of college female students. The covariance structural model and research hypothesis analyzed by using SPSS 16.0 and AMOS 5.0 program. The results are as follows: First, the structural model is accepted significantly. Second, interactivity and shopping value of website have a positive influence on relationship commitment. Third, interactivity, shopping value of website, and relationship commitment have a positive impact on attitude toward the website. Forth, even if shopping value has not a positive influence on attitude toward the website, it was found to have a significant effect on attitude toward the website through the relationship commitment.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.728-733
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• 2001

The subject of this paper is to perform the basic research to make design guide as finding out the structural characteristics of polypropylene Ankle Foot Orthosis(AFO) for hemiplegics. Target shape of AFO is a solid standard type. In this study we measure ridity as dorsiflexion and thicknesses of AFO with three types of ankle widths and analyze correlation between rigidity and ankle widths, thicknesses. As a result, the rigidity characteristic is specified complex effect of ankle widths and thicknesses.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1939-1943
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• 2003

The precise structural analysis of $SnO_{2}$ thin film, which was prepared by PECVD and thickness 2400 ${\AA}$, was tried to do the structural refinement using X -ray diffraction data. The observed diffraction patterns of $SnO_{2}$ thin film had the strongly preferred orientation effect. WIMV method was used to correct the preferred orientation effect. The final weighted R-factor, $R_{WD}$ was 7.92 %. The lattice parameters, a = b == 4.7366(1) ${\AA}$ and c = 3.1937(1) ${\AA}$, were almost in accordance with ones of $SnO_{2}$ powder.

• 한국의류산업학회지
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• 제12권1호
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• pp.60-67
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• 2010

The purposes of this study were to investigate the impacts of shopping value, customer satisfaction, and switching barrier on consumer loyalty to website. For this purpose, the study tested covariance structural model which set relationships among independent variable(shopping value), meditated variables(customer satisfaction and switching barrier), and dependent variable(website loyalty). The data were collected from a sample of 239 internet shopper of college female students. The covariance structural model and research hypothesis analyzed by using SPSS 16.0 and AMOS 5.0 program. The results are as follows: First, the structural model is accepted significantly. Second, shopping value had a positive influence on customer satisfaction and switching barrier. Third, shopping value, shopping satisfaction of customer, and switching barrier had a positive impact on website loyalty. Forth, shopping value had a positive impact on website loyalty directly, it was found to have a indirect effect on website loyalty through customer satisfaction and switching barrier.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 가을 학술발표회 논문집
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• pp.167-174
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• 2001

A shape resistant shell structure is an extremely efficient mechanical creation because it transmits forces mainly by in-plane forces, but at a certain load level it changes from a stable condition to an unstable condition or vise versa. The instability phenomenon of Geiger-type cable dome structure is generated due to the in-plane twisting near critical load level. Therefore the effect of bracing reinforcement is investigated for the Geiger-type model reinforced by bracing. The effect of initial imperfection is also studied since the structural instability behavior characteristic of shell-like structure is significantly sensitive according to the initial condition.