• Journal of the Korean Institute of Intelligent Systems
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• v.13 no.5
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• pp.526-529
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• 2003

Recommender systems or collaborative filtering are methods to identify potentially interesting or valuable items to a particular user Under the assumption that people with similar interest tend to like the similar types of items, these methods use a database on the preference of a set of users and predict the rating on the items that the user has not rated. Usually the preference of a particular user is liable to vary with time and this temporal variation may cause an inaccurate identification and prediction. In this paper we propose a method to adapt the temporal variation of the user preference in order to improve the predictive performance of a collaborative filtering algorithm. To be more specific, the correlation weight of the GroupLens system which is a general formulation of statistical collaborative filtering algorithm is modified to reflect only recent similarity between two user. The proposed method is evaluated for EachMovie dataset and shows much better prediction results compared with GrouPLens system.

• Journal of Digital Convergence
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• v.20 no.3
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• pp.431-438
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• 2022

With the technical development of fourth industrial revolution, VR game market is rapidly expanding. Meanwhile, heavy user group means the group consisting of people consuming certain media or contents more than others, which is the core constituency of the media industry, and there have been only a few studies on them. This study identified the factors that influenced the continuous intention of use of VR game heavy users and figured out their characteristics by verifying the difference in variables with the light user group. According to the results, the heavy user group showed higher behaviors than the light user group in terms of personal innovation, presence, and continuous intention of use variables. In addition to this, it was found that personal innovation, perceived quality, and presence had a significant influence on the continuous intention of use. This study is intended to empirically analyze the characteristics of heavy VR game users and influential factors, thereby preparing baseline data for VR game development and other relevant studies.

• Journal of Korean Library and Information Science Society
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• v.49 no.2
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• pp.357-388
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• 2018

This study aims to analyze library user and circulation status based on the bigdata logs to identify characteristics by user group and propose methods for efficient management of library. The logs to be analyzed consist of user information, circulation information, service usage information registered at the National Library of Korea, Sejong. The user information logs contain 107,369 age data, 106,918 gender data, 106,838 residential data. The circulation information logs contain 536,083 circulation user data, 6,509,369 circulation count data, and the service usage information logs contain 82,813 data. For the analysis of characteristics by user group, the data were used for analyzing user status by age, gender, residence and circulation status by year, month, day. In addition, this study conducts FGI(Focus Group Interview) and linkage analysis with external data to identify factors for analysis results. Based on analysis results, improvement methods for helping library make effective decision-making were proposed. This study analyze empirically user and circulation status based on bigdata logs, and it has significance for being different form proceeding researches with less analysis data.

• Korean Journal of Health Education and Promotion
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• v.30 no.2
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• pp.1-10
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• 2013

Objectives: The objective of this study was to assess the relationship between internet addiction and health behaviors & mental health among Korean adolescents. Methods: Data from the 2010 Korean Youth Risk Behavior Web-based Survey was analyzed. Using the Korean Internet Addiction Proneness Scale for Youth-Short Form: Self Report developed by the Korean National Information Society Agency in 2008, subjects were classified into 3 groups for internet addiction including general user, potential-risk group, and high-risk group. The health behaviors and mental health were compared among the groups for internet addiction by gender. Results: There was significantly higher prevalence of internet addiction including potential-risk group and high-risk group in boys(14.1%) than in girls(8.8%). There were significant odds ratios of perceived stress, perceived depression, perceived health and happiness, and satisfaction of sleeping in both genders at potential-risk group and high-risk group compared to general user for the internet addiction. The odds ratios of smoking at high risk group, alcohol drinking at potential risk group, eating breakfast at high risk group, and moderate physical activity at both risk groups among boys were significant. Among girls at both risk group, the odds ratios of smoking, alcohol drinking, and eating breakfast were significant. Conclusions: This study reveals a significant association among internet addiction, and health behaviors, and mental health in Korean adolescents.

• Journal of Korean Library and Information Science Society
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• v.16
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• pp.129-157
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• 1989

Through this study, some considerations to be taken into account in order to construct the user model for the user friendly system which can provide each individuals user armed with varied intellectual level with the relevant information, can be summarized as follows : (1) The user' ability to use the system and users' subject knowledge, the distribution of the users' level knowledge should be considered for the decision of the typed of interaction between the users and the system. (2) the knowledge of the user models should include the following kinds of knowledge inharmony with one another, 1. Standard user knowledge which represents a general characteristic of user group, 2. individual user knowledge which represents an individual's unique characteristic, 3. Long-term user knowledge which represents the education level and subject background of users, 4. short-term user knowledge which represents the purpose of information science and information need by users (3) As knowledge generation technique, both the implicit method and explicit method should be a n.0, pplied, observation of the system during the interaction, and explicit method generates the knowledge by the user's answering the questions already made by the system. (4) The frame technique as the knowledge representation for the user-modelling in which user-knowledge is represented in a limited situation and in a qualitative aspects, can be recommended. The frame is adequated for the explanation of structured situation, and for the processing the present situation by inferring the previous experiences.

• KIISE Transactions on Computing Practices
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• v.22 no.12
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• pp.675-680
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• 2016

The development of various mobile devices and mobile platform technology has led to a steady increase in the number of online social network (OSN) users. OSN users are free to communicate and share information through activities such as social networking, but this causes a new, user privacy issue. Various distributed OSN architectures are introduced to address the user privacy concern, however, users do not obtain technically perfect control over their data. In this study, the control rights of OSN user are maintained by using personal data storage (PDS). We propose a technique to improve data privacy protection that involves making a group with the user's friend by generating and providing fake text data based on user's real text data. Fake text data is generated based on the user's word sensitivity value, so that the user's friends can receive the user's differential data. As a result, we propose a system architecture that solves possible problems in the tradeoff between service utility and user privacy in OSN.

• Journal of Families and Better Life
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• v.27 no.3
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• pp.201-212
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• 2009

The purpose of research is to investigate patterns and diffusion of consumer participation on Internet UCC based on digital contents services. A sample survey of internet users was conducted, responses were collected from 629 respondents and consumer streaming data were analyzed. Some of the practical implications of the results are follows. Research can find out that patterns of user participation in UCC. The major genres of UCC are like daily lives of individuals, humors, parodies of star entertainers and types of contents like still pictures or images, texts are relatively highly generated comparing with multimedia UCC. Although participants have been being increased in UCC recently, the consumers as prosumers who are classified in contents generating group are ten percents at the most. In generating community-based UCC such as posting answers of questions and activities in Blog, prosumers who are in contents making group(recreational group) show more positive attitudes than simple participants(consuming only). The results of multiple regression analysis indicated that fun & entertainment, arousal, self-expression, user friendly web interface variable commonly posited a significant effect in multimedia UCC Services between two groups. Information sharing and perceived usefulness posited a significant effect in recreational group.

• ETRI Journal
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• v.31 no.5
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• pp.481-488
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• 2009

This paper proposes a new multiuser scheduling algorithm that can simultaneously support a variety of different quality-of-service (QoS) user groups while satisfying fairness among users in the same QoS group in MIMO broadcast channels. Toward this goal, the proposed algorithm consists of two parts: a QoS-aware fair (QF) scheduling within a QoS group and an antenna trade-off scheme between different QoS groups. The proposed QF scheduling algorithm finds a user set from a certain QoS group which can satisfy the fairness among users in terms of throughput or delay. The antenna trade-off scheme can minimize the QoS violations of a higher priority user group by trading off the number of transmit antennas allocated to different QoS groups. Numerical results demonstrate that the proposed QF scheduling method satisfies different types of fairness among users and can adjust the degree of fairness among them. The antenna trade-off scheme combined with QF scheduling can improve the probability of QoS-guaranteed transmission when supporting different QoS groups.

• Korean Journal of Clinical Pharmacy
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• v.26 no.1
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• pp.6-12
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• 2016

Objective: This study aimed to explore the readability and comprehensibility of the drug information on a patient leaflet for the senior by employing performance-based user-testing. Methods: We included 36 elderly (65 years old or older) as the senior group (intervention group) and 36 adults (40~59 years old) as the adult group (control). We developed a questionnaire to test if participants could access to drug information. After completing a questionnaire, the participant was interviewed about their understanding over the patient leaflet. We performed t-test, ${\chi}^2$-test or Fisher's exact test to examine differences between two groups in primary outcomes. Results: The senior were less likely able to find information (78%) than the adult (91%); they were much less likely able to understand information (42%) than the adult (69%). While we found differences between the ability of finding and understanding drug information in both groups, the senior group had greater difficulties in understanding all kinds of drug information. They had significant difficulties to remember information after reading the patient leaflet and frequently failed to find proper information even though they were allowed to access freely to the leaflet during interviewing. Conclusion: To secure safe and effective use of drugs for the senior, it is necessary to develop drug leaflets for the senior.

• Science of Emotion and Sensibility
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• v.13 no.1
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• pp.1-10
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• 2010

This study is about what process and methodology could make UI designer be able to achieve the interface which considers user's mental model through implementing corporate line-up model, when people design an interface between product of multi-function printer and user. The most important concern of UI designers who are dealing with an interface between product and user is how they can make product system image match user's mental model so that users can utilize products without any confusion and discomfort. If concept model which designers bring up and mental model which users expect and recognize could be of one accord, then users can feel ease of use toward products. The understanding and observation for user behavior and use pattern is prerequisite to develop user-centered interface between product and user. However, UI designers do design interface from their own perspective and assumption in many business areas, and users do not react as designers assumed and intended in many cases or examples. This study is to find inappropriate system images against users' mental model on basic function of multi-function printer, and the relationship of system image and user's mental model is diagramed to build up a hypothesis. The hypothesis from this study is validated through evaluation of domestic and international users. In addition, two suggestions to improve usability problems revealed from user test are proposed. The optimal solution is designed based on the result of user evaluation and consideration of many user environments, and then it is implemented to line-up product. In conclusion, this study considers how UI designers can create system image which is close to user's mental model.