In the present study, effective hydrodynamic pressure modeling methods for three-dimensional earthquake safety analysis of a dam intake tower structure are investigated. Time history analysis results using the Westergaard added mass and Chopra added mass methods are compared with the one by the CASI (Coupled Acoustic Structural Interaction) method, which is accepted as giving almost exact solutions, to evaluate the difference in displacement response, stress and dynamic eccentricity. The 3D time history analysis of a realistic intake tower, which has the standard geometry widely used in Korea, shows that the Chopra added mass method gives similar results in displacement and stress and less conservative results in dynamic eccentricity to CASI ones, while the Westergaard added mass yields much more conservative results in all measures. This study suggests to use the CASI method directly for three-dimensional earthquake safety analysis of a dam intake tower, if computationally possible.

Purpose - The purpose of this study is to investigate the relationship among narcissism, usage motives, usage behaviors, satisfaction with and continuance intention to use fashion social media. Research design, data, methodology – A questionnaire survey was used to collect data after conducting a pilot test. Based on the reliability test of the preliminary questionnaire used for the pilot test, the questionnaire was revised. The final questionnaires were administered to 238 fashion social media users and 216 were used for the data analysis. To assess the validity of these measures, exploratory factor analysis and the confirmatory factor analysis were performed. Structural equation modeling analysis were employed for data analysis. Results - Five factors of the usage motivation of fashion social media were extracted: information-seeking, relationshipseeking, practicality-seeking, enjoyment-seeking and self-expression motives. The statistical analysis confirmed the influence of the narcissism tendency on all of the usage motives of fashion social media, three of the fashion social media usage motives influencing information diffusion behavior, and the influence of the information diffusion behavior on users' satisfaction and continuance intention to use fashion social media. Narcissism exerted the highest influences on self-expression motive followed by information-seeking, enjoyment-seeking, relationship-seeking and practicality-seeking motives in order. Factors affecting fashion information diffusion behaviors are practicality-seeking motive, self-expression motive, and relationship-seeking motive. The greater the diffusion of information, the higher the satisfaction with using fashion social media. The consumers with higher satisfaction intended to use fashion social media and share information more frequently. Conclusions - The results indicate that narcissism is an important factor in fashion social media usage motivation. The main motives for narcissistic people to spread information is for the practical purpose at the most, and then to express their personality and style, and to build relationship with others. The satisfaction through active information sharing behaviors seems to play a key role to lead high continuance intention of fashion social media. These implies that marketing strategies to satisfy consumers’ narcissism and motives to use social media, and to stimulate the information diffusion behaviors can be used to meet their needs for higher satisfaction with fashion social media.