• Journal of Information Technology Services
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• v.13 no.3
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• pp.25-50
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• 2014

The purpose of this study is to examine factors affecting the diffusion and the intention to use, and how these factors differ among adopter categories. A survey was done to analyze the diffusion of smart-phone, the most popular and innovative product nowdays. We collected 197 survey questionnaires from smart-phone user and analyzed the data using SPSS 18.0 and Smart PLS 2.0. PLS (Partial Least Square) analysis was implemented before multiple group-innovator, early adopter, eraly majority- analysis which is categoriezed by Innovation Diffusion Model of Rogers (1995). The results show that firstly, in innovator group (n=63), the functional and the safety value have significantly positive effect on user satisfaction. In addition, we found that user satisfaction and the brand loyalty are significatly associated with the intention of use. Secondly, in early adopter group (n = 67), the design value has significantly positive effect on user satisfaction and it has significantly positive effect on brand loyalty. Finally, in early majority group (n = 67), the design value has significantly positive effect on the user satisfaction and it has stronger effect on the intention of use and brand loyalty. We conclude this paper with the implication of this study to both academia, business practice, and policy making.

• Journal of the Ergonomics Society of Korea
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• v.32 no.6
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• pp.557-563
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• 2013

Objective: This study introduces user experience measurement and its application for senior friendly products. Background: Measuring user experience for senior friendly product is very important for its design, but the measurement is not easy. Method: This study was focused on case studies for user experience measurement and its application for senior friendly product. Mobile patient lift and four wheeled walker that assist the old's mobility were studied. User experience was measured through interview and observation method. Result: From measuring the user experience, some usability issues were identified for the products. A method to apply QFD(quality function deployment) in design process was proposed. A design prototype was also developed considering user experience. Conclusion: User experience measurement for senior friendly products is key process for user centered design. Application: The method and result of this study can be applied to user experience measurement and design of senior friendly product.

• Journal of KIISE:Software and Applications
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• v.32 no.7
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• pp.581-591
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• 2005

Collaborative filtering systems have problems involving sparsity and the provision of recommendations by making correlations between only two users' preferences. These systems recommend items based only on the preferences without taking in to account the contents of the items. As a result, the accuracy of recommendations depends on the data from user-rated items. When users rate items, it can be expected that not all users ran do so earnestly. This brings down the accuracy of recommendations. This paper proposes a collaborative recommendation method for extracting typical group preferences using user-item matrix optimization and user profiles in collaborative tittering systems. The method excludes unproven users by using entropy based on data from user-rated items and groups users into clusters after generating user profiles, and then extracts typical group preferences. The proposed method generates collaborative user profiles by using association word mining to reflect contents as well as preferences of items and groups users into clusters based on the profiles by using the vector space model and the K-means algorithm. To compensate for the shortcoming of providing recommendations using correlations between only two user preferences, the proposed method extracts typical preferences of groups using the entropy theory The typical preferences are extracted by combining user entropies with item preferences. The recommender system using typical group preferences solves the problem caused by recommendations based on preferences rated incorrectly by users and reduces time for retrieving the most similar users in groups.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.17 no.2
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• pp.141-148
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• 2006

Objectives : Internet became essential component in these days. This study primarily tried to find out the characteristics of high risk internet users through using the communication scale. Methods : We investigated levels of internet addiction using Internet Addiction Scale in 1,193 high school and middle school students. Participants were divided into 3 groups (high risk user group, potential risk user group, normal user group) according to the results from internet addiction scale. We additionally surveyed characteristics of internet use, and patterns of communication and Communication Scale based on Satir theory in 614 from 1,193 participants. Results : Boys showed higher tendencies for internet addiction than girls in internet addiction scale. There were significant differences in mean computer using time especially during weekends among 3 internet user groups. The distribution of communication types in each internet user group was similar and this finding coincided with previous study results. However high risk user group showed higher scores in each inadequate communication pattern such as placating, blaming, super-reasonable and irrelevant stance. Conclusion : These results suggest that adolescents who use internet in addictive patterns may have more problematic communication styles and these may be associated with poor interpersonal relationships.

• KEPCO Journal on Electric Power and Energy
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• v.7 no.2
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• pp.277-283
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• 2021

Power plant simulators have been used for operator training, control verification and engineering verification. In general, simulators can be used in the place where they are installed by only single user group at a time. Considering high cost of simulator development, a lot of available scenarios, the diversity of user level and accessibility based on users' work location, development of simulator system that can be used by multiple user groups regardless of location is required in order to enhance utilization of simulators. In this paper, the simulator system that can be used by multiple user group simultaneously without location limitation is proposed. The simulator system is composed of simulator servers, database servers, HMI servers, a web server, web clients. Simulator server consists of control model, process model that are developed for Circulating Fluidized Bed power plant located overseas. A web server manages user accounts, operation procedures, multiple server access between web client group and simulator server group. In other words, a web server makes a user group select a simulator server at a time. The developed simulator system is integrated after implementing process model, control model, HMI, and web server. Web client systems are installed on local site where power plant is located, while simulator servers, HMI servers, database servers, and a web server are located in KEPCO RI. The developed simulator system is verified by steady-state test, malfunction test and so on via remote access.

• Journal of radiological science and technology
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• v.42 no.5
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• pp.387-392
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• 2019

This study analyzed the influence of smartphone addiction on adaptation to school life by using the questionnaire survey method of 431 students of radiological science in six regions. The results showed that 89.6% of students are the general user group, 6.3% the high risk group and 4.2% the potential risk group. Adaptability to school life was found to be social adaptability 3.71, righteous adaptability 3.17 and academic adaptability 2.95. Academic adaptability was 3.06 for male students and 2.79 for female students. And righteous adaptability was 3.26 for male students and 3.03 for female students. As a result, male students were more adaptable than female students in academic adaptability and righteous adaptability, which was statistically significant. And Social adaptability was 3.73 for female students and 3.68 for male students, but there was no significant difference(p<.001). Adaptability to school life by smartphone addiction level was found to be the general user group 3.19, the potential risk group 3.05 and the high risk group 2.81. The difference of righteous adaptability between the general user group and the high risk group was statistically significant. And social and academic adaptability of the general user group and the high risk group was no significant(p<.01).

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.256-259
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• 2003

This paper presents mutual authentication scheme between user and network on mobile communications using public key scheme based on counter, and simultaneously shows key agreement between user and user using random number for secure communications. This is also a range of possible solutions to authentication and key agreement problem-authentication and key agreement protocol based on nonce and count, and secure end-to-end protocol based on the function Y=f(.)$\^$1/, C$\^$i/ is count of user I, and f(.) is one way function.

• The Journal of Information Systems
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• v.5
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• pp.345-371
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• 1996

Previous studies on user training have largely focused on assessing models which describe the determinants of information technology usage or examined the effects of training on user satisfaction, productivity, performance, and so on. Scant research efforts have been made, however, to examine those effects of training by using theoretical models. This study presented a conceptual models to predict intention to use information technology and conducted an experiment to understand how training for computer skill acquisition affects primary variables of the model. The data were obtained from 32 student subjects of an experimental group and 31 students of a control group, and the information technology employed for this study was a university electronic mail system. The study results revealed that attitude toward usage and perceived behavioral control helped to predict user intentions ;; outcome expectations were positively related to attitude toward usage ; and self-efficacy was positively related to perceived behavioral control. The hands-on training for the experimental group led to increases in perceived ease of use, self-efficacy and perceived behavioral control. The changes in those variables suggest more causal effects of user training than other survey studies.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1996.10a
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• pp.29-48
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• 1996

Previous studies on user training have largely focused on assessing models which describe the determinants of information technology usage or examined theeffects of training, on user satisfaction, productivity, performance and so on. Scant research efforts have been made, however, to examine those effects of training by using theoretical models. This study presented a conceptural model to predict intention to use information technology and conducted an experimentto understand how training for computer skill acquisition affects primary variables of the model. The data were obtained from 32 student subjects of an experimental group and 31 students of a control group, and the information technology employed for this study was a university's electronic mail system. The study results revealed that attitude toward usage and perceived behavioral control helped to predict user intentions ; outcome expectations were positively related to attitude toward usage ; and self-efficacy was positively related to perceived behavioral control. Thd hands-on training for the experimental group led to increases in perceived ease of use, self-efficacy and perceived behaviroal control. The changes in those variables suggest more causal effects of user training than other survey studies.

• Proceedings of the IEEK Conference
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• summer
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• pp.395-399
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• 2004

We present modality conversion as an effective means for QoS management. We show that modality conversion, in combination with content scaling, would give a wider range of adaptation to support QoS at media level. Here, we consider modality conversion with respect to resource constraint and human factor. To represent modality conversion as well as content scaling, we present the overlapped content value (OCV) model that relates the content value of different modalities with resources. The specification of user preference on modality conversion is divided into qualitative and quantitative levels. The user preference is then integrated into the OCV model so that modality conversion correctly reflects the user's wishes. For the conversion of multiple contents, an optimization problem is formulated and solved by dynamic programming. The experiments show that the proposed approach is efficient to be applied in practice.