• Korean System Dynamics Review
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• v.16 no.3
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• pp.77-96
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• 2015

This study aims to forecast of the number of smart phone addicted youths and to evaluate the effect of rehabilitation programs. A system dynamics model is developed to describe the processes of addiction and transits between phases as well as the diffusion of smart phones. The youths are grouped into non users, general users, potential risky users, and high risky users. The model utilizes the population distributions over ages for the next 30 years forecasted by Korean Government. The number of youths decreases for the next decade or so, and the number of youths who owns smart phone will reach maximum at 2017. As for the rehabilitation programs, the model includes the preventive education for general users, counseling for potential risky users, and professional therapy for high risky users. The preventive education restricts the transit from general users to potential risky users. Counseling increases the transit from potential risky users to general users while it decreases the transit to high risky users. Professional therapy improves transit to potential risky users and to general users. Although the model cannot be validated the accuracy owing to the lack of data, it describes these transit within the reasonable ranges and can be used to study the allocation of the limited resources to maximize the outcome.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2007.11a
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• pp.464-468
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• 2007

In cognitive radio systems, secondary users, unlicensed users, can use primary users' spectrum to increase spectrum efficiency. At that time, the systems must satisfy primary users' QoS. When secondary users use cognitive radio systems, secondary users communication can be terminated, because of satisfying primary users' QoS. However, secondary users' communication terminating is not good for both secondary users and whole systems. So, cognitive radio systems need an efficient algorithm for secondary users of admission control and keeping connections. In this paper, we present an algorithm which consist of two part, admission control and connections control.

• Korean Institute of Interior Design Journal
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• v.18 no.5
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• pp.80-88
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• 2009

The relationship between architects and users has been multifarioiusly changed through architectural history. From the viewpoint of using a building, users who experience and interpret the building are as important as architects who design it. In the past, architects are not interested in the role of users. Modern architects only emphasized the concepts of users based on efficiency, and therefore users had the passive role following the design intentions in the space architects had created. However, since the end of modern movement, diverse definitions of users have been attempted. Especially the aesthetics of reception reilluminates the role of users neglected in modern movement. Therefore the one-way relationship between architects-buildings are changing into the interactive relationship between architects-buildings-users, and it results from the fact that users have the ability to reinterpret and create architectural space as well. Users have more creative and positive role in architectural space making and architects, too, reflect these trend in their architecture.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.8
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• pp.2590-2606
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• 2014

A problem related to deployment of femtocells is how to manage access of users to radio resources. On one hand, all resources of the femtocell can be reserved for users belonging to a closed subscriber group (CSG), which is a set of users defined by a femtocell subscriber. This approach, known as closed access, however, increases interference to users not included in the CSG as those users do not have a permission to access this femtocell. Contrary, resources can be shared by all users with no priority in an open access mode. In this case, the femtocell subscriber shares radio as well as backhaul resources with all other users. Thus, throughput and quality of service of the subscriber and the CSG users can be deteriorated. To satisfy both the CSG as well as non-CSG users, a hybrid access is seen as a compromise. In this paper, we propose a new approach for sharing radio resources among all users. As in common cases, the CSG users have a priority for usage of a part of resources while rest of the resources is shared by all users proportionally to their requirements. As the simulation results show, the proposed resource sharing scheme significantly improves throughput of the CSG users and their satisfaction with granted bitrates. At the same time, throughput and satisfaction of the non-CSG users is still guaranteed roughly at the same level as if conventional sharing schemes are applied.

• Journal of the Korean Data and Information Science Society
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• v.18 no.3
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• pp.619-628
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• 2007

This study is devoted to suggesting the norm of detection abnormal users who are inferior to the other users in the recommender system compared with estimation accuracy. To select the abnormal users, we propose the pre-filtering method by using the preference ratings to the item rated by users. In this study, the experimental result shows the possibility of detecting the abnormal users before the process of preference estimation through the prediction algorithm. And It will be possible to improve the performance of the recommender system by using this detecting norm.

• Journal of the Korean Society of Costume
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• v.51 no.7
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• pp.123-134
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• 2001

The purpose of this study to compare the purchasing behaviour of men's business suits, among custom suits, system order, and ready-made suits, centering around the choice of information source, risk perception and benefits sought. The survey of this study was collected from 450 adult male in Seoul. The data was analyzed by factor analysis and ANOVA. The result of this study were as follows : 1. Custom suits, system order, and ready-made suits consumers have a significant difference in the choice of information source. The consumer attaching most importance to the impersonal information source is the system order users, custom suits users, and ready-made suits users respectively. However there was no significant difference in the personal source among 3 different purchasing behaviour of men's suits. 2. For the risk perception, 1) the group who perceived the highest in economic risk is the system order users, followed by custom suits users, and ready-made suits users. 2) the group who perceived performance risk as being the highest concern is the ready-made suits consumers, followed by system order user, and custom suits user. 3) the group who perceived the socio-psychological risk as the highest is the ready-made suits consumers, and followed by custom suits user and system order users. 4) there is no difference among the three groups with respect to the fashionability loss risk. 5) the group of the highest perceiving the useful loss risk is the ready-made suits consumers, and the next is system order users, custom suits users. 6) the group of the highest perceiving the time and convenience loss risk is ready-made suits users, and the next is system order users, custom suits users. 3. For the benefit sought, the group of the highest perceiving the aesthetics is custom suits consumers, and the next is system order users, ready-made suits users.

• Journal of Korean Academy of Nursing
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• v.51 no.3
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• pp.380-389
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• 2021

Purpose: This study aimed to understand the relationship between cigarette and electronic cigarette (e-cigarette) use and sleep health among Korean adolescents. Methods: Using the 14th Korea Youth Risk Behavior Survey, we included 52,928 adolescents who responded to sleep satisfaction and sleep duration. Participants were classified into four groups: non-users, cigarette-only users, e-cigarette-only users, and dual users of both products. To examine the associations between cigarette and e-cigarette use and sleep health, data were analyzed using complex samples cross tabulation and complex samples logistic regression. Results: Of the four groups, dual users reported the lowest level of sleep satisfaction and sleep duration; 57.0% and 86.9% of dual users were not satisfied with their sleep and have insufficient sleep duration, respectively. The proportion of students who were not satisfied with their sleep was higher among cigarette-only users compared to e-cigarette-only users (52.7% vs. 45.8%), but the two groups reported similar rates of insufficient sleep duration (84.2% vs. 84.3%). Compared to non-users, cigarette-only users, e-cigarette-only users, and dual users were more likely to not be satisfied with sleep (odds ratios [ORs] were 1.49, 1.36, and 1.75, respectively) and had significantly higher odds of experiencing insufficient sleep duration (ORs were 1.85, 2.06, and 2.34, respectively). Conclusion: E-cigarette-only use and dual use as well as cigarette-only use were associated with poor sleep health. Therefore, to improve adolescent sleep health, health professionals should provide sleep intervention strategies considering the association between smoking and sleep health.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.8
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• pp.3187-3200
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• 2020

Finding key users in microblog has been a research hotspot in recent years. There are two kinds of key users: obvious and hidden ones. Influence of the former is direct while that of the latter is indirect. Most of existing methods evaluate user's direct influence, so key users they can find usually obvious ones, and their ability to identify hidden key users is very low as hidden ones exert influence in a very covert way. Consequently, the algorithm of finding hidden key users based on topic transfer entropy, called TTE, is proposed. TTE algorithm believes that hidden key users are those normal users possessing a high covert influence on obvious ones. Firstly, obvious key users are discovered based on microblog propagation scale. Then, based on microblogs' topic similarity and time correlation, the transfer entropy from ordinary users' blogs to obvious key users is calculated and used to measure the covert influence. Finally, hidden influence degrees of ordinary users are comprehensively evaluated by combining above indicators with the influence of both ordinary users and obvious ones. We conducted experiments on Sina Weibo, and the results showed that TTE algorithm had a good ability to identify hidden key users.

• Journal of the Korean Home Economics Association
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• v.41 no.8
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• pp.19-31
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• 2003

This study was intended to present the plan for preventing and solving the seriousness of the consumer problem perceived in the e-commerce. For this purpose, 723 questionnaires were distributed to university As a result of analysis, the following findings were obtained: 1) It was found that e-commerce users had higher knowledge of the degree of internet un, the ability to use information on the internet, the disposition of computerization, and e-commerce related consumer than e-commerce non-users. 2) It was found that e-commerce non-users had the higher level of perceived seriousness of the consumer problem than e-commerce users. Especially, it was found that e-commerce non-users had the high level of perceived seriousness of the consumer problem related to the problem of exchange, termination and after-sale nice and the leakage of exchange, termination and after-sale service and the leakage of private information e-commerce user. 3) It was found that university consumers' perceived seriousness of the consumer problem in e-commerce over the internet showed a significant difference in the ability to use information on the internet between e-commerce users and non-users.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.7
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• pp.840-845
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• 2005

Intelligent agents to learn users' tendency have learn uscrs' tendency by sufficient users information and training time. When the intelligent agents is used in ubiquitous environment, users must wait for intelligent agents to learn, so user may be can't get proper services. In this paper we proposed an intelligent P2P mobile agent system that can learn users' tendency in real-time by sharing users' resource. The system shared users contexts on four places and made feel groups which was composed of similar users. When users' service which had the highest correlation coefficient in the peer groups was suggested, users were satisfied over $80\%$.