• Journal of Korea Multimedia Society
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• v.25 no.8
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• pp.1175-1187
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• 2022

3D interaction between humans and computers has been possible with the popularization of virtual reality, and it is important to study natural and efficient virtual reality user interfaces. In user interface development, it is essential to analyze and evaluate user factors. In order to analyze the influence of factors on users who use the virtual reality color picker, this paper divides the user groups based on whether they major in art or design, whether they have experience in virtual reality, and whether they have prior knowledge about 3D color space. The color selection error and color selection time of all user groups were compared and analyzed. Although there were statistically significant differences according to the user groups, all user groups used the virtual reality color picker accurately and effectively without any difficulties.

• Journal of Information Technology Applications and Management
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• v.19 no.4
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• pp.41-59
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• 2012

This study examines the roles of user resistance and social influences on the acceptance and continuous usage of smartphones at different stages of adoption. The respondents were classified into three groups according to their innovation adoption stage : non-user group, the potential user group and the trial user group. Theories relevant to user resistance, social influences including normative social influences and informational social influences, as well as user adoption and continuance behavior were reviewed and integrated into our research model. In order to verify the proposed structured equation model, we conducted an online survey by targeting mobile phone users and collected data to be analyzed through a partial least squares (PLS) test. This study tested whether there exists differences in the effects of user resistance and different types of social influence on user's adoption or continuance intetion among these three groups. The results showed that user resistance exists in all adopter groups and that it has significant negative influences on intention to use a smartphone. The findings also revealed that user resistance can be enhanced or resolved by two types of social influence; informational social influence resolves user resistance regardless of the adopter category, while normative social influence enhances the user resistance of potential users. Furthermore, the findings show that social influence regardless of the type positively affects user intention. Several theoretic and practical implications pertaining to the results are discussed.

• Journal of Korea Society of Digital Industry and Information Management
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• v.14 no.3
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• pp.77-85
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• 2018

Multi-User Multiple-Input Multiple-Output (MU-MIMO) is the core technology for improving the channel capacity compared to Single-User MIMO (SU-MIMO) by using multiuser gain and spatial diversity. Key problem for the MU-MIMO is the user selection which is the grouping the users optimally. To solve this problem, we adopt Extreme Value Theory (EVT) at the beginning of the proposed algorithm, which defines a primary user set instead of a single user that has maximum channel power according to a predetermined threshold. Each user in the primary set is then paired with all of the users in the system to define user groups. By comparing these user groups, the group that produces a maximum sum rate can be determined. Through computer simulations, we have found that the proposed method outperforms the conventional technique yielding a sum rate that is 0.81 bps/Hz higher when the transmit signal to noise ratio (SNR) is 30 dB and the total number of users is 100.

• Journal of Information Management
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• v.43 no.2
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• pp.23-42
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• 2012

This study is to investigate and analyze the service quality and satisfaction perceived by users and librarians of the Foreign Research Information Center (FRIC). The survey results reveal that three groups of in-campus (internal) user group, external user group and interlibrary loan librarian group has highly perceived the service quality and satisfaction of the FRIC. Two user groups have statistically significant different perceptions on the service quality, loyalty, and satisfaction. Internal user group perceived more highly than external user group, in 6 items of satisfaction, 1 item of loyalty, and 7 items of service quality. Structural equation models of satisfaction and loyalty on two user groups were proved to be appropriate. Material factor including success rate of copied text and general physical status of the copy influences significantly on the user satisfaction in both groups.

• Journal of Contemporary Eastern Asia
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• v.15 no.1
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• pp.78-97
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• 2016

Living labs are an increasingly popular methodology to enhance innovation. Living labs aim to span boundaries between different organizations, among others Triple helix actors, by acting as a network organization typically in a real-life environment to foster co-creation by user-groups. This paper presents critical factors of Living labs in boundary-spanning between Triple Helix actors. Derived from a mixed-method approach and applications in the healthcare sector, the three main critical factors turn out to be 1) an adequate user-group selection and involvement, specifically a rich interaction and absorption of its results, 2) a balanced involvement of all relevant actors, and 3) a sufficient (early) attention for values, both values of user-groups and values of the management. People-oriented Living labs tend to differ from institution-oriented Living labs regarding these critical factors. Further, universities tend to take on diverse roles and strength of involvement, while the business sector tends to be actively involved only if this has been set as an explicit aim at start. The paper closes with a summary and future research paths.

• Journal of KIISE
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• v.43 no.7
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• pp.786-794
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• 2016

Recommender systems can be used to assist users in selecting required services for their tasks in Internet of Things (IoT) environments in which diverse services can be provided by utilizing IoT devices. Traditional research on recommendation mainly focuses on predicting preferences of individual users. However, in IoT environments, not only individual users but also groups of users can access services in the environments. In this study, we analyzed user groups' preferences on services and developed service recommendation approach for new groups that do not have a history of accessing IoT-services in a certain place. Our approach extends the traditional user-based collaborative filtering by considering the similarity between user groups based on their member organization. We conducted experiments with a real-world dataset collected from IoT testbed environments. The results demonstrate that the proposed approach is effective to recommend services to new user groups in IoT environments.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.3
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• pp.1363-1376
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• 2020

An improved clustering scheme based on user group is proposed. Every two users are grouped among N-users in the allowed system according to their link gain from large to small. Each user group is numbered sequentially. Two user clusters are obtained according to the principle of maximizing link gain difference for the users in the first and last user groups. The remaining user groups are added to the two existing user clusters according to the parity of the group number. The clustering should be clustered again among the users in either user cluster if the throughput summation of a user cluster in NOMA is less than that of these users in orthogonal multiple access. The simulation results show that the proposed clustering scheme can increase the system throughput by about 8% compared with the hybrid clustering scheme when the number of users requiring service is 12.

• Journal of the Korean Society for information Management
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• v.31 no.3
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• pp.201-226
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• 2014

This study aims to develop measures to turn former users and non-users of public libraries back into users by understanding the differences between the user, former user and non-user groups in terms of their perceptions to public libraries, as well as the differences between these groups in their perceptions regarding the factors to non-use of public libraries. A literature review and statistical analysis of the results from a questionnaire survey were conducted to identify the differences. The results from the statistical analysis showed significant differences between the user, former user and non-user groups in terms of their perceptions to public libraries and the non-use factors. From the results, we could categorize the factors into common non-use factors, non-use-only factors, and use interrupt factors, and we develop suggestions to improve the factors in order to move non-users and former users to frequent users of the public libraries.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.4
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• pp.111-118
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• 2012

The purpose of this study is to work out strategy for utilization of Environmental Conservation Value Assessment Map (ECVAM) using the user survey. It surveyed system users of ECVAM about its recognition and satisfaction. The results of the survey, the ECVAM became more popular and were highly satisfied with updated data. Especially, the study found a relationship between the satisfaction of ECVAM and accuracy, utilization, and convenience of the system. However, the satisfaction has a difference between user groups, a government official and a agent for EIA including researchers. The satisfaction of the agent group was affected by the convenience, the accuracy, and the utilization in order. In the other hand, the satisfaction of the government official group was affected by the utilization, the convenience, the accuracy, and recognition in order. Therefore, we need to adopt different strategies for educations of ECVAM and publicity activities depending on user groups. To increase the satisfaction of ECVAM, we should research not only to attain pinpoint accuracy, but also to suggest the guideline to utilize the map for a government official.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2008.04a
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• pp.291-296
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• 2008

This paper reports on the results of a questionnaire survey on actual conditions of sleep environment, sleep problems and sleep patterns in bedroom of house. The objectives of survey are: 1) classifying Korean people into several groups by sleep environment condition, sleep problem and life pattern, 2) describing the characteristics of user groups, and 3) searching needs of support for each user group. Despite of several studies about sleep condition that researched in advance, they weren't considered about user's respective characters. So it seems necessary for more studies about users' needs, and segment users to grasp their each detail needs. Therefore, this study conducted questionnaire survey gathering relevant information to classify user groups and to investigate the current bedroom condition. In the result, 702 respondents were divided into six clusters by extracted eight factors. Four clusters of them had some problems for sleep, so it could be seen that they need environmental solution for their good sleep. As the further objective, it will be connected to develop the good sleep system.