• The KIPS Transactions:PartC
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• v.19C no.4
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• pp.235-238
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• 2012

Google Android provides market based application distribution to provide ease use of application services. While openness of Android allows various ways of application distribution, including installation of unsigned application. such openness also invokes critical threats such as the spread of malwares and the illegal distribution of applications. In order to prevent such threats, several distributors use on-line authentication techniques by using mobile subscriber's information. However such methods also have limits that even legal users cannot use their purchased application in situations. Therefore, in this paper, we discuss such problems and provide some ideas of authentication method that allow users to use their purchased application when users change their status.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.5
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• pp.1973-1991
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• 2018

Multimedia applications over wireless networks have been evolving to augmented reality or virtual reality services. However, a rich data size compared to conventional multimedia services causes bandwidth bottlenecks over wireless networks, which is one of the main reasons why those applications are not used widely. To overcome this limitation, bandwidth aggregation techniques, which exploit a multi-path transmission, have been considered to maximize link utilization. Currently, most of the conventional researches have been focusing on the user end problems to improve the quality of service (QoS) through optimal load distribution. In this paper, we address the joint pricing and load distribution problem for multi-homing in heterogeneous wireless access networks (ANs), considering the interests of both the users and the service providers. Specifically, we consider profit from resource allocation and cost of power consumption expenditure for operation as an utility of each service provider. Here, users decide how much to request the resource and how to split the resource over heterogeneous wireless ANs to minimize their cost while supporting the required QoS. Then, service providers compete with each other by setting the price to maximize their utilities over user reactions. We study the behaviors of users and service providers by analyzing their hierarchical decision-making process as a multileader-, multifollower Stackelberg game. We show that both the user and service provider strategies are closed form solutions. Finally, we discuss how the proposed scheme is well converged to equilibrium points.

• 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.

• Journal of Information Processing Systems
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• v.8 no.2
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• pp.191-212
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• 2012

Since a social network by definition is so diverse, the problem of estimating the preferences of its users is becoming increasingly essential for personalized applications, which range from service recommender systems to the targeted advertising of services. However, unlike traditional estimation problems where the underlying target distribution is stationary; estimating a user's interests typically involves non-stationary distributions. The consequent time varying nature of the distribution to be tracked imposes stringent constraints on the "unlearning" capabilities of the estimator used. Therefore, resorting to strong estimators that converge with a probability of 1 is inefficient since they rely on the assumption that the distribution of the user's preferences is stationary. In this vein, we propose to use a family of stochastic-learning based Weak estimators for learning and tracking a user's time varying interests. Experimental results demonstrate that our proposed paradigm outperforms some of the traditional legacy approaches that represent the state-of-the-art technology.

• Journal of Electrical Engineering and Technology
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• v.1 no.3
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• pp.287-294
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• 2006

Recently, switchboards for MV/LV distribution customers have been united and digitalized rapidly. This paper proposes the effective information visualization method for the data measured from cubicle switchboards for MV/LV distribution customers. We developed the algorithm that analyzes abundant data measured by switchboards and displays them to overall users, such as fire information index, power condition index, switchboard safety index, and power diminution index. Using a touch screen made users to operate it easily. User interface was also improved by taking graphic visualization. We guess the information visualization method suggested in this paper shows the new direction that heavy electrical equipments including switchboards are going to develop in the future.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.2
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• pp.177-184
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• 2009

The digital contents distribution system via network provides comfortability, usability, and diversified functions to content's users. However, for the characteristic of easy access of digital contents, the copyright infringements and indiscreet contents distribution are realized in this days. In other words, any users with the authentication key can access to copyright contents with any restrictions. To solve this problems, we proposed a user authentication mechanism which prevent indiscreet access to the digital content by using user system information. Also, to provide safe distribution of digital content, we used user's unique content authentication key.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.6
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• pp.1380-1386
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• 2015

Recently, the importance of users' geographic location information has been highlighted with a rapid increase of online social network services. In this paper, by utilizing geo-tagged tweets that provides high-precision location information of users, we first identify both Twitter users' exact location and the corresponding timestamp when the tweet was sent. Then, we analyze a relationship between the tweet frequency and the average user velocity. Specifically, we introduce a tweet-frequency computing algorithm, and show analysis results by country and by city. As a main result, it is shown that the tweet frequency according to user velocity follows a power-law distribution (i.e., Zipf' distribution or a Pareto distribution). In addition, by performing a comparison between the United States and Japan, one can see that the exponent of the distribution in Japan is smaller than that in the United States.

• Journal of Distribution Science
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• v.13 no.8
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• pp.97-104
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• 2015

Purpose - This study examines the positive impact of the social distance between producers and users of online content, investigating and analyzing the most popular Web content. In addition, it tries to elicit the matching effect that appears when the individuals'cultural background is consistent with social distance. Research design, data, and methodology - We collected and analyzed actual data about 4,981 videos clips on YouTube, looking at six countries in order to verify the content of this study. Based on the results of the data analysis, the study conducted behavioral measurements on popularity, social distance, culture, and user engagement. The unit of analysis was the content and we collected information about the content producers and the content records. We controlled the views, comments, likes, calendar dates, and ages in the empirical models. The data was collected in 2011, with the records coming from South Korea, Japan, China, U.S., German, and France. A total of 4,980 elements were analyzed in the model. The empirical model estimated is the bivariate negative binomial distribution (NBD) model. Results - It turns out that there is a possibility that the matching effect can be diminished by variables that reflect the psychological involvement of user engagement. This study proposes academic and practical implications based on these research results. This research shows the positive effect of social distance between users and producers on the increased performance of the online content. We find the effect of social distance to be a stronger tendency in collectivism. The collectivists follow their sense of friendship and intimacy in their culture and, the social congruence effect can be found there as well. The effect, however, could erode in a social case where users are motivated by strong intrinsic and psychological factors. In addition, user engagement complicates the process of user decision making regarding the information. Conclusions - This study examines how the differential effects of social distance caused by culture could disappear through user commitment as a complicated user motivation. Some potential implications are as follows. First, a firm in the collectivism culture has to communicate based on the social distance. In fact, most online channels do not have a function that indicates the social distance as measured by favorites or subscribers. This function could help increase the performance of the content in online channels, but this increasing effect can only be found in a collectivist culture. Based on this, the firms have to communicate and announce to users the actual social distance between users and producers. Second, firms should develop a system that discovers the social distance and culture and shows these measures to users and producers, since the congruence effect between social distance and culture is found only for low user engagement. The firms can take the advantage of the congruence effect only for the development of the social distance and culture visualized system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.6
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• pp.1996-2013
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• 2015

This paper considers a scenario that more D2D users exist in the cell, they compete for cellular resources to increase their own data rates, which may cause transmission interference to cellular users (CU) and the unfairness of resource allocation. We design a resource allocation scheme for selfish D2D users assisted by cooperative relay technique which is used to further enhance the users' transmission rates, meanwhile guarantee the QoS requirement of the CUs. Two transmission modes are considered for D2D users: direct transmission mode and cooperative relay transmission mode, both of which reuses the cellular uplink frequency resources. To ensure the fairness of resource distribution, Nash bargaining theory is used to determine the transmission mode and solve the bandwidth allocation problem for D2D users choosing cooperative relay transmission mode, and coalition formation game theory is used to solve the uplink frequency sharing problem between D2D users and CUs through a new defined "Selfish order". Through theoretical analysis, we obtain the closed Nash bargaining solution under CUs' rate constraints, and prove the stability of the formatted coalition. Simulation results show that the proposed resource allocation approach achieves better performance on resource allocation fairness, with only little sacrifice on the system sum rates.

• Journal of Distribution Science
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• v.21 no.6
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• pp.91-97
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• 2023

Purpose: Interim financial statements provide timely and qualified financial information for users. Hence, the importance of the interim financial statement is increasingly noticeable among information users. This research studies determinants of interim financial statements disclosure in Vietnamese-listed enterprises. Research design, data and methodology: The sample is 55 enterprises listed in VNIndex and is in the list of Forbes top 100 largest companies in 2020. Data was collected from interim financial statements for four years, from 2018 to 2021. GMM is used in this study. Results: The regression analysis results show that reporting lag has a positive impact on the level of information distribution of interim financial reporting; companies audited by BIG4 tend to have a higher level of information disclosure. The higher the return on assets, the more disclosure is made; the larger the company size, the greater the disclosure level. Owner equity structure and Leverage do not affect the disclosure level of interim financial reporting. Conclusions: The information disclosure level on the interim financial statement should be improved to increase transparency. In addition to continuing to encourage these companies to provide more information voluntarily, government authorities should have effective regulations to require sufficient information disclosure from other listed companies.