• Journal of the Korea Society of Computer and Information
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• v.15 no.8
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• pp.163-171
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• 2010

This research has studied developing the persona model based on alan cooper's user oriented design which is newly in the limelight in the field of product design process. As developing the persona model, In-depth interview and FGI(focus group interview) has been conducted for extracting car navigation user group's motivation and using attribute. Based on research, three different car navigation user group were divided-low using & understanding the function group, medium using & well understanding the function group, heavy using & well understanding the function group. This research yielded the foundation for setting the persona model and this persona gives the key factor for producing the user oriented user Interface design after all.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.7
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• pp.3319-3338
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• 2016

Cloud storage is becoming more and more popular because of its elasticity and pay-as-you-go storage service manner. In some cloud storage scenarios, the data that are stored in the cloud may be shared by a group of users. To verify the integrity of cloud data in this kind of applications, many auditing schemes for shared cloud data have been proposed. However, all of these schemes do not consider the access authorization problem for users, which makes the revoked users still able to access the shared cloud data belonging to the group. In order to deal with this problem, we propose a novel public auditing scheme for shared cloud data in this paper. Different from previous work, in our scheme, the user in a group cannot any longer access the shared cloud data belonging to this group once this user is revoked. In addition, we propose a new random masking technique to make our scheme preserve both data privacy and identity privacy. Furthermore, our scheme supports to enroll a new user in a group and revoke an old user from a group. We analyze the security of the proposed scheme and justify its performance by concrete implementations.

• Journal of Information Processing Systems
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• v.10 no.4
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• pp.568-580
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• 2014

To enhance the utilization of the traffic channels of a network (instead of allocating radio channel to an individual user), a channel or a group of channels are allocated to a user group. The idea behind this is the statistical distribution of traffic arrival rates and the service time for an individual user or a group of users. In this paper, we derive the blocking probability and throughput of a subscriber station of Worldwide Interoperability for Microwave Access (WiMAX) by considering both the connection level and packet-level traffic under a complete partition scheme. The main contribution of the paper is to incorporate the traffic shaping scheme onto the incoming turbulent traffic. Hence, we have also analyzed the impact of the drain rate of the buffer on the blocking probability and throughput.

• Journal of Multimedia Information System
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• v.4 no.3
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• pp.145-150
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• 2017

Recently, game companies are having difficulties in exactly figuring out the right consumer groups for their games. To solve this problem, a system algorithm which recommends user-customized games based on the user information entered has been proposed in this study. Game developers will be able to clearly determine the consumer group(s) of both on and off-line games through accumulated data while consumers can find the game they desire. It is expected that the gaming culture will advance further with the proposed algorithm.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2006.06a
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• pp.344-353
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• 2006

Nowadays many people participate in online communities for information sharing. But most recommender systems are designed for personalization of individual user, so it is necessary to develop a recommendation procedure for group users, such as participants in online communities. This paper proposes a group recommender system to recommend books for group users in online communities. For such a purpose, we suggest a group recommendation procedure consisting of two phases. The first phase is to generate recommendation list for 'big user' using collaborative filtering, and the second phase is to remove irrelevant books among previous list reflecting the preference of each individual user. The procedure is explained step by step with an illustrative example. And this procedure can potentially be applied to other domains, such as music, movies and etc.

• Annals of Clinical Neurophysiology
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• v.5 no.1
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• pp.16-20
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• 2003

Background: Mobile phone has become a very popular device used in everyday our lives. However, the possible hazard to human body such as brain tumor has been proposed intermittently. This unwanted possibility was calmed down due to the absence of definite evidence of hazard. This study was performed to see the effect of mobile phone use on the brain temperature. Methods: In 20 volunteers, we performed 4 steps of temperature measuring procedure. Four steps are pre-use (S1, basal state), wire-phone (S2, conventional telephone), PCS phone (S3, using 1,750~1,900 MHz), cellular phone (S4, using 820 MHz) states. Brain temperatures were measured by radiothermometer at 10 sites (5 sites in each hemisphere) of the brain after 5minutes of telecommunication through the phones. The final data were compared using paired t-test. Results: In PCS phone user group (Average; $35.73708^{\circ}C$), brain temperature decreased (with statistical significance, p<0.05), compared to those of non-user group (Average; $35.9527^{\circ}C$) or conventional wire phone user group. In cellular phone user group (Average; $35.82155^{\circ}C$), brain temperature decreased slightly (without statistical significance, p>0.05) compared to those of non-user group (Average; $35.9527^{\circ}C$) or conventional wire phone user group (Average; $35.922^{\circ}C$). The temperature change was not limited to the mobile phone applied side but on both hemisphere of the brain. Conclusion: In conclusion, mobile phone (especially PCS phone) decreased brain temperature in both hemispheres without side-to-side temperature difference. In addition, this study suggests possibility of radiothermometer application to the study of electromagnetic wave effect and protection method research in the future.

• Journal of the Korea Society of Computer and Information
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• v.21 no.9
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• pp.65-72
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• 2016

Vehicle and marine navigation which are currently being commercialized provide route guidance service by specifying a fixed position as a destination. In the route guidance service of existing navigation, if the destination has to be changed in the middle, a new destination must be designated again to obtain the navigation service. However, if the destination can't be designated, it is difficult to clearly use it. In this paper, in order to overcome the difficulties of directions in the existing navigation, a new navigation specifying moving targets as the destination has been developed to get the directions. A proposed system is that a group is made and a group manager is appointed as a destination and then a user can get the route guidance based on location of the group manager. In the service way, relationship between the group manager and user is one-to-many and relationship between the user and group manager is one-to-one. The proposed technology is able to provide services that the user can easily find the moving targets such as the positioning surrogate drivers, tracking routes and location among travelers and finding children.

• Journal of The Korean Association of Information Education
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• v.18 no.2
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• pp.203-212
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• 2014

With regard to recently emerged problems of smartphone addiction among adults and adolescents, this paper researched upper-grade elementary students depending on various demographic factors that have not been studied thoroughly so far. The survey was conducted on 1570 students in grades 4~6 of schools in Gyeonggi province. Results showed that, first, the average rate of smartphone ownership was about 66%. Second, about 1% of the students belonged to high-risk group, 5.7% to at-risk group, and normal user group was 93.3%. Third, based on the demographic factors, grade and academic achievements each was significantly correlated to the type of addiction group. For example, students with poor academic performance or in higher grade were more likely to be highly addictive. Fourth, both groups of at-risk and of normal-user pertaining to these factors - in urban areas, male students, sixth-grade, in dual income families - showed higher addictiveness score. But they were contrasted in the aspects of household economy and academic performance: at-risk group was more addictive in affluent families or excellent academic performance, whereas normal-user group had higher level of addictiveness in case of poor families or lower academic performance.

• Journal of the Korean Institute of Educational Facilities
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• v.20 no.3
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• pp.3-12
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• 2013

The study explored empirically user participatory design methods for realizing user demand efficiently and evaluating alternatives systematically by using design indicators such as the design quality indicators system of the UK. In the empirical exploratory process utilizing design indicators, the study selected design indicators, and conducted a survey of design realization methods, evaluation methods, and user participatory design utilizing design indicators. Also, concerning the empirical exploratory process, it can be classified into a preliminary survey aimed at those majoring in architecture; a user group survey aimed at elementary school students, parents, and teachers; and a professional group survey aimed at professionals in architecture. In particular, the study carried out the survey for the empirical exploratory process of user participatory design by combining on-line and off-line methods.

• Journal of the Korea Society of Computer and Information
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• v.8 no.4
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• pp.57-62
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• 2003

At the beginning stage of design process, the concept design is required to equip the creative idea thinking and exerts critical effect on the success of production. To support the idea thinking process at the stage of concept design, web-based Creative Group Thinking System(CGTS) was developed. In this vein, the purpose of this study is to investigate the significance of HCI(Human Computer Interface) and UI(User Interface) and to find the way to increase the applicability of the UI of CGTS.