• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.1
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• pp.446-465
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• 2015

In this modern era of technology and information, e-learning approach has become an integral part of teaching and learning using modern technologies. There are different variations or classification of e-learning approaches. One of notable approaches is Personal Learning Environment (PLE). In a PLE system, the contents are presented to the user in a personalized manner (according to the user's needs and wants). The problem arises when a new user enters the system, and due to the lack of information about the new user's needs and wants, the system fails to recommend him/her the personalized e-learning contents accurately. This phenomenon is known as cold-start problem. In order to address this issue, existing researches propose different approaches for recommendation such as preference profile, user ratings and tagging recommendations. In this research paper, the implementation of a novel interaction-based approach is presented. The interaction-based approach improves the recommendation accuracy for the new-user cold-start problem by integrating preferences profile and tagging recommendation and utilizing the interaction among users and system. This research work takes leverage of the interaction of a new user with the PLE system and generates recommendation for the new user, both implicitly and explicitly, thus solving new-user cold-start problem. The result shows the improvement of 31.57% in Precision, 18.29% in Recall and 8.8% in F1-measure.

• Journal of the Korea Society of Computer and Information
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• v.21 no.7
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• pp.9-16
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• 2016

Collaborative filtering(CF) uses the purchase or item rating history of other users, but does not need additional properties or attributes of users and items. Hence CF is known th be the most successful recommendation technology. But conventional CF approach has some significant weakness, such as the new user problem. In this paper, we propose a approach using word embedding with skip-gram for learning distributed item representations. In particular, we show that this approach can be used to capture precise item for solving the "new user problem." The proposed approach has been tested on the Movielens databases. We compare the performance of the user based CF, item based CF and our approach by observing the change of recommendation results according to the different number of item rating information. The experimental results shows the improvement in our approach in measuring the precision applied to new user problem situations.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.8
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• pp.2061-2080
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• 2013

Roaming authentication protocol is widely used in wireless network which can enable a seamless service for the mobile users. However, the classical approach requires the home server's participation during the authentication between the mobile user and the foreign server. So the more the roaming requests are performed the heavier burden will be on the home server. In this paper, we propose a new roaming authentication framework for wireless communication without the home server's participation. The new roaming authentication protocol in the new framework takes advantage of the ID-based cryptography and provides user anonymity. It has good performance compared with the roaming authentication protocols whose authentication do not need the home server's participation in terms of security and computation costs. Moreover, a new User-to-User authentication protocol in the new framework is also present. All the authentications proposed in this paper can be regarded as a common construction and can be applied to various kinds of wireless networks such as Cellular Networks, Wireless Mesh Networks and Vehicle Networks.

• Journal of the Ergonomics Society of Korea
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• v.33 no.3
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• pp.175-189
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• 2014

Objective: The goal of this research is to develop new user behavior model using user motion analysis with microscopic perspective for attracting user's participation in interactive space. Background: The interactive space is 'human's place', which is made up of complex elements of digital virtual space and traditional analog and physical environment based on human-computer interaction system. Human behavior has changed in it at the same time. If the user couldn't make participation in interaction, the purpose of the system is not met, which reduces its effect. Therefore, we need to focus on interactive space that is potential future direction from a new point of view. Method: For this research, we would discuss and study fields of interactive space; (1) finding definition of interactive space and studying background of theory about it. (2) providing base of user behavior model with study of user's context that is to be user information and motion. (3) examining user motion, classify basic motion type and making user participation behavior model in phases. Results: Through this process, user's basic twenty motions which are systematized are taken as a standard for analysis of interaction process and participation in interactive space. Then, 'NK-$I^5$ (I Five)' model is developed for user participation types in interactive space. There are five phases of user participation behavior: Imperception, Interest, Involvement, Immersion, and Influence. In this analysis, three indicators which are time, motion types, and user relationship are found to be related to participation. Conclusion: The capabilities and limitation of this research is discussed to attract user participation. This paper focuses especially on contribution of design to lead user's participation in interactive system and expectation to help adapt to user centered design of various interactive space with new aspect of user behavior research. Application: The results of the 'NK-$I^5$ (I Five)' model might help to realize successful interactive space based on user centered design.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.04a
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• pp.914-915
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• 2017

Importance and usage of the recommender system increases with the increase of information. The accuracy of the system recommendation primarily depends on the data. There is a problem in recommender systems, known as cold start problem. The lack of data about new products and users causes the cold start problem, and the system will not be able to give correct recommendation. This paper deals with cold start problem by comparing product specification and the review of the resembled products. The user, who likes the resembled product of the new one has more probability of taking interest in the new product as well. However, if a user disagreed with resembled product due to some reasons which the user mentioned in the reviews. The new product overcomes that issue, so the user will greatly accept the new product. Therefore, the system needs to recommend new product to those users as well, in this way the cold start problem will get resolved.

• Journal of the Ergonomics Society of Korea
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• v.31 no.4
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• pp.557-565
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• 2012

Objective: This paper focuses on the new trend of applying NUI(natural user interface) such as gesture interaction into television and investigates on the design improvement needed in application. The intention is to find better design direction of NUI on television context, which will contribute to making new features and behavioral changes occurring in next-generation television more practically usable and meaningful use experience elements. Background: Traditional television is rapidly evolving into next-generation television thanks to the influence of "smartness" from mobile domain. A number of new features and behavioral changes occurred from such evolution are on their way to be characterized as the new experience elements of next-generation television. Method: A series of expert review by television UX professionals based on AHP (Analytic Hierarchy Process) was conducted to check on the "relative appropriateness" of applying gesture interaction to a number of selected television user experience scenarios. Conclusion: It is critical not to indiscriminately apply new interaction techniques like gesture into television. It may be effective in demonstrating new technology but generally results in poor user experience. It is imperative to conduct consistent validation of its practical appropriateness in real context. Application: The research will be helpful in applying gesture interaction in next-generation television to bring optimal user experience in.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2005.11a
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• pp.63-66
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• 2005

The purpose of this study is to suggest the modeling of ubiquitous environments according to the analysis of user's behaviors focused on the living area within the house. Recently, with appearing 'Ubiquitous environments', the applications of ubiquitous technologies on the our environment adopt a new paradigm. This new paradigm leads to the possibility of creating more intellectual dwelling environment according to user's behaviors. This paper suggests to change our dwelling by considering both engineering technology and the character of dwelling, because the house should provide causes humans with comfortability. Therefore, we need to understand user's behaviors in the dwelling, towards user friendly environment. Also, it very important for us to configure proper sensors and technologies by the priority based on user's behaviors. To sum up, this study is aimed to analyze user's behaviors and then, to suggest the guideline for users offering optimal ubiquitous environments.

• Archives of design research
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• v.16 no.2
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• pp.35-48
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• 2003

Home networking technology connects individual home appliances through a wired or wireless network and makes possible new functions that were impossible when they were used independently. However, the new functions must not simply be confusing arrays of functions that are possible to implement, but those absolutely necessary to the users. To develop innovative information appliances with such functions, scenarios were used and played guiding roles in suggesting new product ideas, making design mockups, and producing videos to show natural situations where the products would be used in home of the future. In the phase of suggesting new product ideas, user action scenarios in the home, generated by a team consisting of experts in the fields of cognitive engineering, user interface, computer science, cultural anthropology, interaction design, and product design, helped the team identify user needs and design factors necessary to fulfill those needs and suggest new product ideas from the design factors. In the phase of making design mockups, the procedures of using the products were described in the scenario format. Based on the scenarios the s쇼les and the user interfaces of them were designed. In the phase of producing videos, the interactions between the user and the product were embodied in the course of professional writers'arranging the scenarios of using the products for the scripts of the videos. Videos were produced to show the actual situations where the design mockups would be used in home of the future and the dynamic aspects of interaction design.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2006.05a
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• pp.202-205
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• 2006

Space design is a process of solving spatial problems to create and construct all kinds of human lives. It also bestows new values to a medium to induce human perception based on the relationships between 'human and space' surrounding people. Research on user behavior has several ultimate goals including understanding both individual behavior and the relations between the user and space from a more scientific and systematic perspective, predicting various phenomena that can happen between space and humans, and reflecting the results in space design. As user behavior that's once limited within given space is going through some changes due to the introduction of digital technologies, research on user behavior in today's space design should be newly illuminated in the aspects of organic relations. Space now works as a receptor communicating with the user and responding to user behavior, and user behavior once under one-sided influences from space becomes more diverse and active. The influences of user behavior, in turn, cause changes to space itself. Thus this study set out to suggest new directions in research on user behavior based on interactions between space and the user in space design.

• Electronics and Telecommunications Trends
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• v.36 no.4
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• pp.135-144
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• 2021

The field of user authentication in Korea has experienced new dimensions since December 2020. Accredited certificate, which had been in use for 21 years since 1999, has been abolished. Accredited certificates have provided a trust foundation for various ICT-based industrial developments; however, new changes in the authentication sector are also required due to changes in the service and policy environment. Changes in the service environment occur rapidly because of the emergence of new technologies such as AI, IoT, Bio, Blockchain, and the daily use of non-face-to-face environments caused by COVID-19. Even with changes in the service environment, user authentication remains an essential foundation for providing services. This paper summarizes the current status of user authentication techniques, analyzes major changes in the service environment (such as Metaverse) associated with user authentication, and presents the direction of authentication techniques (Decentralized, Invisible, Privacy-preserving) through the derived implications.