• International journal of advanced smart convergence
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• v.9 no.3
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• pp.49-58
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• 2020

Non-orthogonal multiple access (NOMA) has been recognized as a significant technology in the fifth generation (5G) and beyond mobile communication, which encompasses the advanced smart convergence of the artificial intelligence (AI) and the internet of things (IoT). In NOMA, since the channel resources are shared by many users, it is essential to establish the user fairness. Such fairness is achieved by the power allocation among the users, and in turn, the less power is allocated to the stronger channel users. Especially, the first and second strong channel users have to share the extremely small amount of power. In this paper, we consider the power optimization for the two users with the small power. First, the closed-form expression for the power allocation is derived and then the results are validated by the numerical results. Furthermore, with the derived analytical expression, for the various channel environments, the optimal power allocation is investigated and the impact of the channel gain difference on the power allocation is analyzed.

• Proceedings of the Korean Society of Computer Information Conference
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• 2013.07a
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• pp.321-323
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• 2013

Supporting communications among users, Social Network has encouraged various information flows through relationships among them. This paper studies on mentality or attitude of Social Network Services (SNS for short) users, on the basis of Technology Acceptance Model (TAM for short) and then proposes so-called TAMS, Technology Acceptance Model for Social Network Services. SNS users make full use of SNS as channels in order to create, expand, and obtain some information related to personal concerns. We will research on how the benefits that users get by using SNS exert influence on user-perceived usability. The SNS-using benefits focus on relationship benefits that are formed by interactions among users. Provided that perceived usability affects mental or informational benefits according to involvement of SNS users, we will check how perceived usability or ease of use is connected to brand attitude.

• Proceedings of the Korea Association of Information Systems Conference
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• 1997.10b
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• pp.271-285
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• 1997

This paper address the issues of satisfaction factors to measure the service quality in computer communication service users. In order to develope a satisfaction factors' model, we study appropriate quality factors of the service through the focus group interviews with service users, and surveys the quality levels that users have felt in services. It also analyzes the relationship between the user's quality level and the quality factors by the statistical analyses. Based on the optimal regression model, we suggest an appropriate satisfaction model in PC communication service areas. That model shows that most users are interested in the fare for use. Use-fare factor is the most powerful one to the satisfaction model. Second one is usefulness, next is correctness. But connect-status factor is the only negative one. Most users think that its factor is in the way of fluent communication. So to keep the competitiveness in the PC communication service, the sixth negative factor should be modified as soon as possible.

• International Journal of Human Ecology
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• v.14 no.2
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• pp.79-91
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• 2013

The market for a payday advance, regarded as both a convenient and short term-loan for immediate financial help, has grown incredibly since the 1990's. Despite its popularity by borrowers and the possible benefits, it has received negative publicity. Some borrowers have been caught in a debt trap for a long-term period and at tripledigit interest rates. The objective of this study is to shed light on the borrowers' profiles and their demand for a payday advance. Based on the 2010 household level data from the U.S. Federal Reserve Board, this study finds that payday advance users are pronounced as seemingly risky people. Payday advance users tend to be college drop-outs, African Americans, and non-homeowners compared to non-payday advance users. They are more likely to overspend above their income and have a favorable attitude toward conspicuous spending than non-payday advance users. They tend not to shop at all nor perform even moderate shopping for credit before using a payday advance service as opposed to non-payday advance users.

• International Journal of Contents
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• v.8 no.3
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• pp.7-11
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• 2012

This study examines A-list users in the Twitter network of National Assembly members in South Korea. An examination of some socio-geographic characteristics of these A-list users indicates that the distribution of these users in terms of their geographic location and social status can be understood in the context of the Korean social structure. In addition, an examination of Tweets posted by these users shows that half of these users had negative attitudes toward the current administration and that some Tweets contained emotional terms.

• Review of Korean Society for Internet Information
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• v.14 no.3
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• pp.95-100
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• 2013

Having taken actions for 2 years, Net Neutrality User Forum has realized Net Neutrality as a international issue of future Internet. Although the Internet design principle (layering, module, IP protocol) has enabled the end users to communicate each other without any additional permission or interference, in the reality, the end users have been tracked by both companies and governments, and the communications could be blocked, or restricted by surveillance devices, such as DPI, which could change the whole Internet design principle. Given that the Internet is a large community of the equal end-users based on end-to-end principle, it's essentially the issues of the whole Internet users, rather than of one nation, and we should focus on developing the transparent and participatory ways in Internet governance. The current Internet governance discussion have taken placed in ICANN, IGF, etc., in bottom-up processes of multistakeholderism to reflect the views of end-users. However there have been the controversial issues in Internet Governance, such as the position of government as a stakeholder, global north-south problem, transparency, so we have faced the debate on the new or evolving frame of Internet governance.

• Journal of Information Science Theory and Practice
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• v.2 no.3
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• pp.18-28
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• 2014

Reddit is a large user generated content (USG) website in which users form common interest groups and submit links to external content or text posts of user-created content. The web site operates on a voting system whereby registered users can assign positive or negative ratings to both submitted content and comments made to submitted content. While Reddit is a pseudonymous site, with users creating usernames but providing no biographical data, an informal survey posted to a large shared interest community yielded 734 responses including age and gender of users. This provided a large amount of contextual biographical data with which to analyse user profiles at the first level of Computer Mediated Discourse Analysis (CMDA), articulated by Susan Herring. The results indicate that older Reddit users both formulate more complex writing and enjoy more success when rated by other users. Gender data was incomplete and as such only tentative results could be proposed in that regard.

• Journal of the Korean Society for Railway
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• v.10 no.4
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• pp.420-430
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• 2007

It is reported that many users of the subways in Seoul are not currently satisfied with the subway services. The cause of the dissatisfaction is that the qualitative items and indexes are not considered properly, and also does not diversify the evaluation items to follow the change of subway environment. Therefore in this study the evaluation items and indexes that can reflect of the subway users' characteristics are examined and synthesized. Then the characteristics of service are analyzed for the senior subway system users and junior subway system users that are classified with the cluster analysis. The result of the study is that the majority of users on subway are not satisfied the qualitative items which are safety, kindness, comfortableness, convenience excepting for punctuality and accessibility. So, if the service of subway users improve, the qualitative items is needed to consider with quantitative items.

• Journal of information and communication convergence engineering
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• v.1 no.2
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• pp.74-81
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• 2003

There are many researches on visual languages, but the most of them are difficult to support various collaborative interactions on a distributed multimedia environment. So, this paper suggests a collaborative visual language for interaction between multi-users. The visual language can describe a conceptual model for collaborative interactions between multi-users. Using the visual language, generated visual sentences consist of object icons and interaction operators. An object icon represents a user who is responsible for a collaborative activity, has dynamic attributes of a user, and supports flexible interaction between multi-users. An interaction operator represents an interactive relation between multi-users and supports various collaborative interactions. Merits of the visual language are as follows: supporting of both asynchronous interaction and synchronous interaction, supporting flexible interaction between multi-users according to participation or leave of users, supporting a user oriented modeling, etc. For example, an application to a workflow system for document approval is illustrated. So we could be found that the visual language shows a collaborative interaction.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.36 no.1
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• pp.64-69
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• 2013

In ubiquitous computing, shared environments adjust themselves so that all users in the environments are satisfied as possible. Inevitably, some of users sacrifice their satisfactions while the shared environments maximize the sum of all users' satisfactions. In our previous work, we have proposed social welfare functions to avoid a situation which some users in the system face the worst setting of environments. In this work, we consider a more direct approach which is a preference based clustering to handle this issue. In this approach, first, we categorize all users into several subgroups in which users have similar tastes to environmental parameters based on their preference information. Second, we assign the subgroups into different time or space of the shared environments. Finally, each shared environments can be adjusted to maximize satisfactions of each subgroup and consequently the optimal of overall system can be achieved. We demonstrate the effectiveness of our approach with a numerical analysis.