• Archives of design research
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• v.9
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• pp.101-114
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• 1994

This study deals with the issue of actual HCI design embodiment through the investigation on how to interpret and use visual expression means in HCI design in a semantic way. The purpose of this study is to provide the method by which designers can make the user-centered guidelines in HCI design. As a part of the user\ulcornercentered design approaches, this study is based on the understanding of user group types which are divided by his/her extent of exposure to computer especially and is focussed on applying the level of each group's apprehension of visual expression means to the embodiment of HCI design. Major findings of this study are: First, it proposes the 'Visual Tokens Models' as a basic source for the understanding and the embodiment of visual expression means in HCI design; Second, it has examined the correlations between the characteristics of Visual Tokens and user group types that is, naive users, casual users, and expert users; Third, it proposes guidelines for the user-centered embodiment of HCI design in accordance with the correlations.

• Journal of Intelligence and Information Systems
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• v.9 no.3
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• pp.117-135
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• 2003

This study is to propose a procedure solving scale problem of traditional collaborative filtering (CF) approach. The CF approach generally uses some similarity measures like correlation coefficient. So, as the user of the Website increases, the complexity of computation increases exponentially. To solve the scale problem, this study suggests a clustering model-based approach using Self-Organizing Map (SOM) and RFM (Recency, Frequency, Momentary) method. SOM clusters users into some user groups. The preference score of each item in a group is computed using RFM method. The items are sorted and stored in their preference score order. If an active user logins in the system, SOM determines a user group according to the user's characteristics. And the system recommends items to the user using the stored information for the group. If the user evaluates the recommended items, the system determines whether it will be updated or not. Experimental results applied to MovieLens dataset show that the proposed method outperforms than the traditional CF method comparatively in the recommendation performance and the computation complexity.

• Journal of the Korean Data and Information Science Society
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• v.17 no.3
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• pp.717-726
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• 2006

This study is to investigate the MAE of prediction value by collaborative filtering algorithm originated by GroupLens and improved algorithm. To decrease the MAE on the collaborative recommender system on user based, this research proposes the improved algorithm, which reduces the possibility of over estimation of active user's preference mean collaboratively using other user’s preference mean. The result shows the MAE of prediction by improved algorithm is better than original algorithm, so the active user's preference mean used in prediction formula is possibly over estimated.

• Korean Institute of Interior Design Journal
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• v.25 no.5
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• pp.140-147
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• 2016

This research aims to establish the size standard of university library's user space, and present the standard and method to calculate total area required in the planning of new building construction and remodeling. Nine university libraries newly constructed or remodeled since 2000 were selected among the libraries of large scale universities with more than 10,000 enrolled students as the target libraries in this research. The target libraries were classified into A group (five cases partially remodeled) and B group (four cases newly constructed or fully remodeled) on the basis of the change of times. A university library can be divided into three spaces (user space, administration space and public space). This research classified the reading room in the user space into bookshelf zone, reading zone, information/office zone and hall/other zone, and analyzed area ratio according to each zone. B group's bookshelf zone decreased 12% more than A group, and B group's reading zone increased 10% more than A group. However, there was no big change in the area ratio of information/office zone and hall/other zone. This can be interpreted that university library changes from book and archive preservation-oriented space to user-oriented space. This research presented a proper reading room area calculation method, based on the capacity of books, by reflecting such a change. Each zone's standard was set up through classification of domestic and international standards, based on which, the calculation method of university library's total floor area required was presented. The reason why there was difference in university library's total floor area required according to domestic standard and international standard was that the number of enrolled students per seat in the reading room was different. The area calculation methods presented in this research can be utilized as useful data upon planning university library construction or remodeling.

• Journal of Internet Computing and Services
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• v.3 no.5
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• pp.87-94
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• 2002

This paper proposes a group key management protocol for a secure of all the multcast user in PIM-SM multicast group communication. Each subgroup manager gives a secure key to it's own transmitter and the transmitter compress the data with it's own secure key from the subgroup manager, Before the transmitter send the data to receiver, the transmitter prepares to encrypt a user's service by sending a encryption key to the receiver though the secure channel. after checking the user's validity through the secure channel, As the transmitter sending a data after then, the architecture is designed that the receiver will decode the received data with the transmitter's group key, Therefore, transmission time is shortened because there is no need to data translation by the group key on data sending and the data transmition is possible without new key distribution at path change to shortest path of the router characteristic.

• Convergence Security Journal
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• v.2 no.2
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• pp.19-27
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• 2002

This paper proposes a group key management protocol for a secure of all the multicast user in PIM-SM multicast group communication. Each subgroup manager gives a secure key to it's own transmitter and the transmitter compress the data with it's own secure key from the subgroup manager. Before the transmitter send the data to receiver, the transmitter prepares to encrypt a user's service by sending a encryption key to the receiver though the secure channel, after checking the user's validity through the secure channel. As the transmitter sending a data after then, the architecture is designed that the receiver will decode the received data with the transmitter's group key. Therefore, transmission time is shortened because there is no need to data translation by the group key on data sending and the data transmition is possible without new key distribution at path change to shortest path of the router characteristic.

• Convergence Security Journal
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• v.2 no.1
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• pp.99-107
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• 2002

This paper proposes a group key management protocol for a secure of all the multicast user in PIM-SM multicast group communication under electronic commerce. Each subgroup manager gives a secure key to it's own transmitter and the transmitter compress the data with it's own secure key from the subgroup manager. Before the transmitter send the data to receiver, the transmitter prepares to encrypt a user's service by sending a encryption key to the receiver though the secure channel, after checking the user's validity through the secure channel. As the transmitter sending a data after then, the architecture is designed that the receiver will decode the received data with the transmitter's group key. Therefore, transmission time is shortened because there is no need to data translation by the group key on data sending and the data transmition is possible without new key distribution at path change to shortest path of the router characteristic.

• Journal of Information Technology Services
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• v.16 no.1
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• pp.119-138
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• 2017

Mobile easy payment is a term for using mobile devices to facilitate financial transactions. Mobile easy payment is a quickly emerging practice, supported by the dramatic increase of mobile phone or device users around the world. The purpose of this study is to classify user's group of the mobile easy payment service by their lifestyle based on I-VALS type and to investigate differences in usage behavior among the user groups. For empirical study, a questionnaire survey was carried out with users of mobile easy payment services using the Internet from June 7 to 10 in 2016. We conducted factor analysis for I-VALS, usage factors, satisfaction factors. We also performed cluster analysis for group classification, and analysis of variance, cross analysis to compare the different usage behavior among the user groups. In analysis results, first three cluster appeared including "ICT task-oriented group", ICT positive and socialities oriented group", "ICT leader-oriented group". Second, it was found significant differences among the clusters about factor of "easy of use", "securities", "universality", "satisfaction". Third, we showed that there were significant differences in time first used the service. Based on these findings, we provide practical implications. Results of our study can be expected to provide the basis of differentiated marketing strategy of mobile easy payment services.

• Journal of the Ergonomics Society of Korea
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• v.29 no.3
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• pp.297-310
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• 2010

The purpose of this study is to investigate the user characteristics in different age groups by investigating the level of satisfaction and preference of design and function of mobile phone. 160 subjects participated in the experiment. Subjects with different ages were selected and divided into four groups: young age group (20 to less than 45), $1^{st}$ middle age group (45 to less than 55), $2^{nd}$ middle age group(55 to less than 65), and elderly group(over 65). A questionnaire was developed based on the previous design guideline, and additional questions were made to test newly developed function and design of the mobile phone. In particular, depth interviews were conducted in order to have a proper response from old subjects who have difficulties in completing written questionnaire. In result, it was found that except for price the major criterion to purchase mobile phone was the design, and the function of phone was the next except for elderly group. In the case of elderly group, the screen size is the first. Statistical results indicated that 37.5% of the young age group, 22.5% of $1^{st}$ middle age group, 22.5% of $2^{nd}$ middle age group and 10.0% of the elderly group preferred the design to function when they purchase mobile phones. Most elderly people were not satisfied with the supplementary function of the mobile phone. The $1^{st}$ middle age group did not know exactly how to use the supplementary service although they were willing to use it. Regarding the emotional preference on the type of phone, the sliding type was preferred most. Current results can be used to anticipate the future trend of mobile phone and design a user-friendly product for the aged population.

• Proceedings of the Korea Association of Information Systems Conference
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• 1996.11a
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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 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 model 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'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 and perceived behavioral control. The changes in those variables suggest more causal effects of user training than other survey studies.