• Journal of Korean Society of Steel Construction
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• v.17 no.2 s.75
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• pp.217-225
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• 2005

The purpose of this study is to investigate the behavior of H-shape column base plates subjected to axial loads and moments. In this study, the behavior of H-shape column base plates is investigated using finite element analysis method and an analytical modelingof the base plates is obtained. The variations of six test specimens include ratiosof axial load, sizes of anchor bolts, and thicknesses of base plates. The experimental results are compared with the results from the finite element analyses and those of the analytical modeling. Bearing pressures of base plates from the finite element analyses are compared with those that are assumed in the design of the base plates. From the results of the research, it is observed that the initial stiffness and yield strengths in the analytical study are very similar to the experimental results. And bearing pressures are concentrated under column section with thin base plates.

• Computers and Concrete
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• v.26 no.3
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• pp.203-211
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• 2020

Turkey is located in one of the most seismically active regions of in Europe. The majority of the population living in big cities are at high seismic risk due to insufficient structural resistance of the existing buildings. Such a seismic risk brings the need for a comprehensive seismic evaluation based on the risk analysis in Turkey. Determining the seismic resistance level of existing building stock against the earthquakes is the first step to reduce the damages in a possible earthquake. Recently in January 2020, the Elazig earthquake brought the importance of the issue again in the public. However, the excessive amount of building stock, labor, and resource problems made the implementation phase almost impossible and revealed the necessity to carry out alternative studies on this issue. This study aims for a detailed investigation of residential buildings in Antalya, Turkey. The approach proposed here can be considered an improved state of building survey methods previously identified in Turkey's Design Code. Antalya, Turkey's fifth most populous city, with a population over 2.5 Million, was investigated as divided into sub-regions to understand the vulnerability, and a threshold value found for the study area. In this study, 26,610 reinforced concrete buildings between 1 to 7 stories in Antalya were examined by using the rapid visual assessment method. A specific threshold value for the city of Antalya was determined with the second level examination and statistical methods carried out in the determined sub-region. With the micro zonation process, regions below the threshold value are defined as the priority areas that need to be examined in detail. The developed methodology can be easily calibrated for application in other cities and can be used to determine new threshold values for those cities.

• The Journal of Society for e-Business Studies
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• v.19 no.2
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• pp.53-74
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• 2014

Ubiquitous City(U-City) is spotlighted for the new paradigm to solve the problem of urbanization using ICT technology. However, due to the lower profit and the insufficient of citizen-experience service, ubiquitous service(U-Service) is perceived negatively. In this sense, a study for user-centric profitable service development is needed. This study, as a basic research for the development of U-service, is conducted to identify the factors which are affected to acceptance of the U-Service. Technology Acceptance Model is applied for the basic model of the research. The model is modified by the U-City characteristic which has user, technology, and service perspective. The proposed model is empirically tested using survey data collected from 600 citizens of 7 U-City. Structural equation modeling is employed to test the research hypotheses. The survey analysis results are able to apply for basic research of U-Service design, and provide theoretical and practical implications.

• The Journal of Information Systems
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• v.26 no.4
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• pp.107-135
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• 2017

Purpose Along with the growth of smart phones and social networking service (SNS), social commerce continues to expand. Although online reviews have become an important source of the information that consumers use to make purchasing decisions, theoretical development and empirical testing in this area are still limited. Thus, there is a need to develop further understanding about the influence of electronic word-of-mouth (eWOM). Drawing upon the heuristic - systematic model (HSM) which is one of the dual-process theories, this study develops a research model that explains key factors influencing consumers' eWOM credibility. Furthermore, this study verifies that consumer's eWOM credibility is a key determinant of eWOM and purchase intentions. Design/methodology/approach The proposed model is empirically tested with 493 users who have experience in WeChat-based social commerce. The structural equation model (SEM) analysis is used to evaluate the research model and hypotheses. Findings The major findings are as follows. First, argument quality of eWOM (a systematic factor) has a positive effect on eWOM credibility. Second, source credibility and recommendation consistency of eWOM (heuristic factors) are positively associated with eWOM credibility. Finally, purchase and eWOM intentions greatly depend on eWOM credibility. These results confirm the effectiveness of HSM in explaining eWOM mechanisms in SNS-based social commerce. The details of findings and implications are presented.

• Structural Engineering and Mechanics
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• v.41 no.4
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• pp.495-508
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• 2012

The strength theory of concrete is significant to structure design and nonlinear finite element analysis of concrete structures because concrete utilized in engineering is usually subject to the action of multi-axial stress. Experimental results have revealed that lightweight aggregate (LWA) concrete exhibits plastic flow plateau under high compressive stress and most of the lightweight aggregates are crushed at this stage. For the purpose of safety, therefore, in the practical application the strength of LWA concrete at the plastic flow plateau stage should be regarded as the ultimate strength under multi-axial compressive stress state. With consideration of the strength criterion, the ultimate strength surface of LWA concrete under multi-axial stress intersects with the hydrostatic stress axis at two different points, which is completely different from that of the normal weight concrete as that the ultimate strength surface is open-ended. As a result, the strength criteria aimed at normal weight concrete do not fit LWA concrete. In the present paper, a multi-axial strength criterion for LWA concrete is proposed based on the Unified Twin-Shear Strength (UTSS) theory developed by Prof Yu (Yu et al. 1992), which takes into account the above strength characteristics of LWA under high compressive stress level. In this strength criterion model, the tensile and compressive meridians as well as the ultimate strength envelopes in deviatoric plane under different hydrostatic stress are established just in terms of a few characteristic stress states, i.e., the uniaxial tensile strength $f_t$, the uniaxial compressive strength $f_c$, and the equibiaxial compressive $f_{bc}$. The developed model was confirmed to agree well with experimental data under different stress ratios of LWA concrete.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.3A
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• pp.139-148
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• 2012

Circular concrete-filled tubes (CFTs) are composite members, which consists of a steel tube and concrete infill. CFTs have been used as building columns and bridge piers due to several advantages such as their strength-to-size efficiency and facilitation of rapid construction. Extensive experimental studies about CFT have been conducted for past decades. However experimental results alone are not sufficient to support the engineering of these components. Complementary advanced numerical models are needed to simulate the behavior of CFT to extend the experimental research and develop predictive tools required for design and evaluation of structural systems. In this study, a finite element modeling technique for CFT was developed. The confinement effects, and behavior of CFT subjected various types of loading predicted by the proposed finite element model for CFT were verified by comparing with test results.

• Journal of the Korea Society of Computer and Information
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• v.18 no.10
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• pp.47-54
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• 2013

In this paper, the structural design of optical Internet is analyzed and by using UNI (User Network Interface) signaling protocol an optical transmission experiment was performed. The hierarchical structure of the basic optical Internet consists of the backbone network, the service network and the access network. The necessary functions for each layer were described as follows: Control structure of the optical transport layer, network operation and management structure, internetworking technology of sub networks, routing and signaling technology. By using UNI signaling protocol from OIF (Optical Internetworking Forum), the optical transmission in the proposed structure of the optical Internet network was experimented. By the traffic generation of LSP (Label Switched Path) data packets along the route-configuration was delivered to UNI. Finally, by showing the value of TCP (Transmission Control Protocol) packets the optical transmission was completely and successfully demonstrated.

• Journal of Aerospace System Engineering
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• v.11 no.6
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• pp.26-33
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• 2017

We propose a variable frame structure connected with telescopic mast-shaped shaft for a robot displaying outstanding ability to cross obstacles, and for effective traction control. The wireless control system was built to extend and contract a deployable mechanism, which is shaped into a hoberman sphere assembled with frame structures. In order to develop important parameters for efficient locomotion, we derived an Euler-Lagrange equation for the spherical robot. According to the equation, the DC motor was selected. A prototype mechanism was tested and a Finite-Element Analysis (FEA) was conducted in parallel. Using these data, we constructed a deployable spherical robot with structural stability. The deployable robot moved at a speed of 0.85 m/s from 520 mm to 650 mm.

• Human Ecology Research
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• v.58 no.4
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• pp.539-560
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• 2020

This study presents work-family multiple-role planning by female university students as a new approach to worklife balance. Accordingly, this study examines university years as a key time frame during which students establish their career paths. This study integrates the social cognitive career theory and the planned behavior theory to design and evaluate a model that explains the work-family multiple-role planning process; in addition, it develops an optimal model to predict the intentions of female university students in work-family multiple-role planning. This study has conducted a structural survey with 500 female university students. After inspecting the data, the responses of 435 participants were used in the data analysis (SEM) with SPSS 21.0 and AMOS 21.0. The findings include the following. First, suitability of predictive model presents a satisfying fit. The major factors in this study's model (parental support, subjective norms, attitudes toward multiple-role planning, career decision self-efficacy, and outcome expectations) are verified as direct and indirect predictors of the work-family multiple-role planning intent of female university students. Second, the strongest predictive factor for the work-family multiple-role planning intent is the social environment factor (subjective norms), indicating that the influence of social pressure on intent is relatively large. The predictive model formulated under this study's integrated theoretical framework supplements existing research that focused on attitudes toward multiple-role planning as well as provides a more profound theoretical foundation on which work-family multiple-role planning behaviors can be better understood.

• Journal of the Korean Electrochemical Society
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• v.23 no.2
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• pp.39-46
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• 2020

Composite electrodes for rechargeable batteries generally consist of active material, electric conductor, and polymeric binder. And their composition and distribution within the composite electrode determine the electrochemical activity in the electrochemical systems. However, it is not easy to quantify the physical properties of composite electrodes themselves using conventional experimental analysis tools. So, 3D structural modeling and simulation can be an efficient design tool by looking into the contact areas between particles and electric conductivity within the composite electrode. In this study, while maintaining the composition (LiCoO₂ : Super P Li^® : Polyvinylidene Fluoride (PVdF) = 93 : 3 : 4 by wt%) and loading level (13 mg cm^-2) of the composite electrode, the effects of LiCoO₂ size (10 ㎛ and 20 ㎛) and electrode density (2.8 g cm^-3, 3.0 g cm^-3, 3.2 g cm^-3, 3.5 g cm^-3, 4.0 g cm^-3) on the physical properties are investigated using a GeoDict software. With this tool, the composite electrode can be efficiently designed to optimize the contact area and electric conductivity.