• Structural Engineering and Mechanics
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• v.68 no.4
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• pp.459-473
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• 2018

Temperature fields and temperature deformations induced by time-varying solar radiation, shadow, and heat exchange are of great importance for the ride safety and quality of the maglev system. Accurate evaluations of their effects on the dynamic performances are necessary to avoid unexpected loss of service performance. This paper presents a numerical approach to determine temperature effects on the maglev train/guideway interaction system. Heat flux density and heat transfer coefficient of different components of a 25 m simply supported concrete guideway on Shanghai High-speed Maglev Commercial Operation Line is calculated, and an appropriate section mesh is used to consider the time-varying shadow on guideway surfaces. Based on the heat-stress coupled technology, temperature distributions and deformation fields of the guideway are then computed via Finite Element method. Combining guideway irregularities and thermal deformations as the external excitations, a numerical maglev train/guideway interaction model is proposed to analyze the temperature effect. The responses comparison including and excluding temperature effect indicates that the temperature deformation plays an important role in amplifying the response of a running maglev, and the parameter analysis results suggest that climatic and environmental factors significantly affect the temperature effects on the coupled maglev system.

• Transactions of Materials Processing
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• v.25 no.1
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• pp.49-55
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• 2016

Electrohydraulic forming (EHF) is a high-speed forming process that uses an electric arc discharge in water. Shock waves resulting from the electric arc discharge are propagated to the blank through water and the blank moves toward the die. Advantages of EHF include improved formability due to the high-speed process and reduction of the bouncing effect. In the current study, a numerical simulation of EHF was developed using LS-DYNA. In the simulation, the model for the electric arc was assumed as an adiabatic gas expansion and an Arbitrary Lagrange-Eulerian (ALE) multi material formulation was used to describe the interaction between the electric arc and the water. In order to model the Fluid-Structure Interaction (FSI), a coupling mechanism was used. The blank of Al 1100-O was simulated using shell elements. The results of the simulation showed that the blank was deformed due to the pressure propagation of water and the bouncing effect did not affect the formability of blank.

• The Journal of the Korea Contents Association
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• v.11 no.9
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• pp.212-224
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• 2011

Users in the Web 2.0 era, which is based on the convergence of wired and wireless technologies, tend to have a high regard for digital contents interactions, as compared to the technology experienced at the analog era. To boost the digital contents business, it is necessary to focus on the digital contents(DC) interactions based on user-centered thinking to satisfy user preferences. According to previous studies, this study classified DC interactions into three types: interaction between users, interactions between contents and users, and interactions between system and users. This study empirically verifies that DC interactions factors affect flow as well as DC flow influences the DC use intention.

• Structural Engineering and Mechanics
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• v.19 no.6
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• pp.619-637
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• 2005

The objective of this research was to determine the Vlasov soil parameters for quadratically varying elasticity modulus $E_s$(z) of the compressible soil continuum and discuss the interaction affect between two close plates. Interaction problem carried on for uniformly distributed load carrying plates. Plate region was simulated by Kirchhoff plate theory based (mixed or displacement type) 2D elements and the foundation continuum was simulated by displacement type 2D elements. At the contact region, plate and foundation elements were geometrically coupled with each other. In this study the necessary formulas for the Vlasov parameters were derived when Young's modulus of the soil continuum was varying as a quadratic function of z-coordinate through the depth of the foundation. In the examples, first the elements and the iterative FE algorithm was verified and later the results of quadratic variation of $E_s$(z) were compared with the previous examples in order to discuss the general behavior. As a final example two plates close to each other resting on elastic foundation were handled to see their interaction influences on the Vlasov foundation parameters. Original examples were solved using both mixed and displacement type plate elements in order to confirm the results.

• Structural Engineering and Mechanics
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• v.10 no.6
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• pp.517-532
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• 2000

A direct output feedback control scheme was recently proposed by the authors for single-story building structures resting on flexible soil body. In this paper, the control scheme is extended to mitigate the seismic responses of multi-story buildings. Soil-structure interaction is taken into account in two parts: input at the soil-structure interface/foundation and control algorithm. The former reflects the effect on ground motions and is monitored in real time with accelerometers at foundation. The latter includes the effect on the dynamic characteristics of structures, which is formulated by modifying the classical linear quadratic regulator based on the fundamental mode shape of the soil-structure system. Numerical result on the study of a $\frac{1}{4}$-scale three-story structure, supported by a viscoelastic half-space of soil mass, have demonstrated that the proposed algorithm is robust and very effective in suppressing the earthquake-induced vibration in building structures even supported on a flexible soil mass. Parametric studies are performed to understand how soil damping and flexibility affect the effectiveness of active tendon control. The selection of weighting matrix and effect of soil property uncertainty are investigated in detail for practical applications.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.4
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• pp.193-200
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• 2019

Maintenance services provided to users in buildings are not sufficient simply to provide them, but it is necessary to provide them with a service system that can accurately identify and respond to users' needs. This study analyzed the relationship between user satisfaction with the helpdesk service corresponding to the building claim and the quality of service of the maintenance organization to identify the interaction between the user and the maintenance organization in the building. We then examined whether there were significant differences between the buildings in terms of variables in the helpdesk service that affect the user's satisfaction. It was also presented as a measure of the quality of service of the SERVQUAL tool to assess the potential for building maintenance response strategies. Research shows that each building has a helpdesk service item that is significant in user satisfaction and empathy has emerged in a typical dimension as SERVQUAL dimension.

• East Asian Journal of Business Economics (EAJBE)
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• v.10 no.3
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• pp.1-15
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• 2022

Purpose - This study explored factors of online education that affect student dissatisfaction and learning effectiveness in higher education during the COVID-19 pandemic. Research design, data, and methodology - This study combined qualitative and quantitative designs. The qualitative part of this study involved in-depth interviews using a criteria-based purposive sampling technique. The quantitative part of this study consisted of an online survey. Results - The qualitative results revealed that students faced significant problems related to online learning, including a lack of learning environment, interaction, and support from the school. The quantitative results indicated that the effects of transitioned-online courses on student dissatisfaction were higher with student support, the interaction between students and instructors, online learning environment, and course organization and evaluation based on the order, while the effects on learning effectiveness were higher with the online learning environment, interaction between students and instructors, course organization and evaluation, and student support based on the order. Conclusion - The results implied that online learning in the era of the COVID 19 pandemic negatively affects student satisfaction and learning effectiveness. Policymakers and school leaders should improve students' satisfaction and learning effectiveness when confronted with the pandemic. Better policies should be adopted to improve better way of teaching in the era of COVID19.

• Journal of Korean Society for Quality Management
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• v.39 no.1
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• pp.24-33
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• 2011

This paper investigates the quality determinants in the consulting service for small and medium sized company. The results of the analysis show that the quality dimension is composed of two factors, consulting skills and interaction, and consulting skills are composed of understanding, expertise, and reliability. Also, this paper examines how the quality factors affect customer satisfaction and loyalty using a structural equation model. The result shows that all consulting skills affect customer satisfaction and customer satisfaction affects customer loyalty. The consulting results have an effect on customer satisfaction but have no direct influence on customer loyalty.

• International Journal of Contents
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• v.10 no.3
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• pp.64-72
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• 2014

This study explored the elements that affect team achievements in virtual environments. In this study, consideration was given to the role of group dynamics in facilitating productive interaction. We aspired to reveal the mechanisms of group dynamics and examined how group dynamics affected team achievements in virtual environments. The empirical study was performed with undergraduate students enrolled in an e-learning course. In collaboration with other majors, students executed team projects and managed project issues in forums or chat rooms. The results of the empirical study indicated that leadership, creative friction, and group cohesion (components of group dynamics) had positive relationships with team achievements. The findings confirmed that addressing creative conflict is a method to improve team performance and that leadership is a key factor in project teams.

• Archives of Pharmacal Research
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• v.27 no.9
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• pp.978-983
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• 2004

The effects of glycyrrhizic acid (GLZ) on protein binding of diltiazem, verapamil, and nifedipine were investigated. Protein binding studies (human serum, human serum albumin (HSA) and (X1-acid glycoprotein (AAG)) were conducted using the equilibrium dialysis method with and without addition of GLZ. The binding parameters, such as the number of moles of bound drug per mole of protein, the number of binding sites per protein molecule, and the association con-stant, were estimated using the Scatchard plot. The serum binding of nifedipine, verapamil, and diltiazem was displaced with addition of GLZ, and the decreases of Ks for serum were observed. GLZ decreased the association constants of three drugs for HSA and AAG, while the binding capacity remained similar with addition of GLZ. Although the characteristics of interaction were not clear, GLZ seemed to mainly affect HSA binding of nifedipine rather than AAG binding, while GLZ seemed to affect both AAG- and HSA-bindings of verapamil and dilt-iazem resulting in a serum binding displacement.