• Journal of Information Processing Systems
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• v.5 no.3
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• pp.151-158
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• 2009

This paper proposes a utility-based data rate allocation algorithm to provide high-quality mobile video streaming over femtocell networks. We first derive a utility function to calculate the optimal data rates for maximizing the aggregate utilities of all mobile users in the femtocell. The total sum of optimal data rates is limited by the link capacity of the backhaul connections. Furthermore, electromagnetic cross-talk poses a serious problem for the backhaul connections, and its influence passes on to mobile users, as well as causing data rate degradation in the femtocell networks. We also have studied a fixed margin iterative water-filling algorithm to achieve the target data rate of each backhaul connection as a counter-measure to the cross-talk problem. The results of our simulation show that the algorithm is capable of minimizing the transmission power of backhaul connections while guaranteeing a high overall quality of service for all users of the same binder. In particular, it can provide the target data rate required to maximize user satisfaction with the mobile video streaming service over the femtocell networks.

• KSCI Review
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• v.14 no.1
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• pp.273-285
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• 2006

This study compares choice of contents genre between mobile VOD service users and landline internet VOD service users. Overall, males showed a higher rate of VOD usage than females and a variety of contents were used for entertainment, programs and mood alteration. In addition, a higher frequency of VOD usage showed a higher rate of VOD usage and also resulted in higher level of satisfaction. Also, the quality of landline internet VOD service showed to be higher than mobile VOD service. This suggests that programs for mobile VOD needs to be developed as well as a more open and simple rate system. In addition, subjects of this study showed to use VOD services mainly for entertainment purposes, suggesting that a variety of programs need to be developed in order to higher the level of satisfaction of its users.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.3
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• pp.63-72
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• 2021

Mobile crowd-sensing (MCS) is a promising sensing paradigm that leverages mobile users with smart devices to perform large-scale sensing tasks in order to provide services to specific applications in various domains. However, MCS sensing tasks may not always be successfully completed or timely completed for various reasons, such as accidentally leaving the tasks incomplete by the users, asynchronous transmission, or connection errors. This results in missing sensing data at specific locations and times, which can degrade the performance of the applications and lead to serious casualties. Therefore, in this paper, we propose a missing data inference approach, called missing data approximation with probabilistic tensor factorization (MDI-PTF), to approximate the missing values as closely as possible to the actual values while taking asynchronous data transmission time and different sensing locations of the mobile users into account. The proposed method first normalizes the data to limit the range of the possible values. Next, a probabilistic model of tensor factorization is formulated, and finally, the data are approximated using the gradient descent method. The performance of the proposed algorithm is verified by conducting simulations under various situations using different datasets.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.3
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• pp.53-62
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• 2015

Recently, number of tablet or Smartphone users increased significantly in domestic and around the world. But violation of personal information such as leakage, misuse and abuse are constantly occurring by using mobile devices which is very useful in our society. Therefore, in this paper it will talk about the problems in the network environment of the mobile environment such as tablet and Smartphone, Mobile Malware, hacking of the public key certificate, which could be potential threat to mobile environment. This thesis will research for people to use their mobile devices more reliable and safer in mobile environment from invasion and leakage of personal information. In order to use Smartphone safely, users have to use Wi-Fi and Bluetooth carefully in the public area. This paper will research how to use App safely and characteristic of risk of worm and Malware spreading. Because of security vulnerabilities of the public key certificate, it will suggest new type of security certification. In order to prevent from the information leakage and infect from Malware in mobile environment without knowing, this thesis will analyze the improved way to manage and use the mobile device.

• The Journal of Information Systems
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• v.20 no.3
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• pp.81-109
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• 2011

The increase in the number of smartphone users has recently been steep, which started to offer companies and individuals more opportunities to enter into a new business field. Furthermore, the smartphone applications have become one of the hottest topics inside and outside the mobile industry. Still the market is in its infancy and intention to pay of charged application of most smartphone users is relatively low. However, rate of charged application in appstore is expected to be increase steadily for some years to come. In this perspective, it is important to consider the smartphone mobile application. Research on smartphone application is still in its early stage. Thus, the purpose of this study is to find what are the effective factors on user satisfaction and intention to pay of mobile application. Based on information system success model, we proposed system quality(stability, usability, security), information quality(timeliness, accuracy, enjoyment) and service quality(reactivity, reliability, empathy) as factors to effect on user satisfaction in mobile application. The results showed that stability, usability, timeliness, accuracy, enjoyment, reactivity and empathy affected significantly user satisfaction. The relationship among satisfaction and intention to pay of mobile application was significantly supported. The implications of the findings is that firms and individual developers of mobile application should focus on customer retention through enhancing satisfaction and quality.

• Journal of Digital Contents Society
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• v.13 no.4
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• pp.575-582
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• 2012

Mobile SNS like facebook is famous as an app which users cooperate others and share information without regard to time and place. But it is necessary to evaluate the mobile app accessibility in view of the disabled and the aged to check if they get appropriate interface service to use such a popular app. Mobile app accessibility is an indicator of equal opportunity to mobile app for all users regardless of cognitive and physical attribute. Therefore, this paper evaluates accessibility of facebook and kakaotalk mobile SNS, apprehend the status of conform to the manual, and suggest an improving way, based on 'mobile application accessibility guideline' announced by government and 'mobile application (Android) accessibiliy checking manual(v1.0)' by National Information society agency.

• Journal of Technology Innovation
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• v.14 no.3
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• pp.183-208
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• 2006

Mobile banking is one of the most representative services applied to the mobile technology. However, there are few recent studies about the user acceptance of mobile banking, and prior studies only have been related to the positive effects of the service acceptances such as e-commerce and Internet banking service. The purpose of this research is to grasp the particular risk essentials in mobile banking which customers perceive, and the risk degree of user recognition which affect customer intention to adopt mobile banking through the exploratory research. The perceived risk is segmented into the performance risk, financial risk, time risk, social risk (or psychological risk), and privacy risk based on Cunningham's research (1967) and other recent studies. In the Unified Theory of Acceptance and Use of Technology (UTAUT), we have attempted to determine how different perceived risks have influence on the mobile banking adoption intentions of both the mobile banking users and potential users. The results indicate that performance expectancy, effort expectancy, and social influence have positive influences on the intention to use mobile banking service while perceived risk has a negative influence on the intention to use and performance expectancy.

• The Transactions of the Korea Information Processing Society
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• v.6 no.5
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• pp.1143-1152
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• 1999

A Mobile computing environment is a new paradigm which provides users with the access to information irrespective of users' location. A transaction scheduling method for the mobile computing environment must be designed so that database consistency is maintained with considering the limited performance of mobile hosts and the narrow bandwidth of a wireless network. The scheduling method using a lock has some problems: the high message overhead between a server and a mobile host for maintaining a lock and the high abort ratio of the mobile transactions owing to violating the serializability when a mobile host uses a cache. So, in this paper, we propose an efficient transaction management method using timestamp to resolve these problems. The proposed method is used in the environment under which a mobile host uses a cache having two versions for each cached data item and a server maintains several versions for each data item. So, even though a mobile transaction is executed during several broadcasting interval, can be committed. As a result, the proposed method can improve the commit ratio of the mobile transactions by maintaining multiversion for each data item and does not require the additional message exchange to schedule transactions by using timestamp.

• Journal of Information Technology Services
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• v.18 no.2
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• pp.17-35
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• 2019

The objective of this study is to extract affecting factors on game satisfaction of a mobile game through the two mediated variables, self-fulfillment and flow. To apply mobile environment changed into the research model of a mobile game, we classify independent factors into three types such as system characteristics, cognitive characteristics, and individual characteristics. The previous studies for using mobile game have been based on intrinsic motivation, such as flow, as a mediated factor. However, the flow variable has some limitations in explaining user satisfaction aspects of mobile game, and the self-fulfillment variable is popularly used as an important mediated factor in the field of sports science. Because users of mobile game often attain their goals as sports event, we utilize self-fulfillment as well as flow as mediated variables. We developed a research model that includes independent factors, mediated variables of self-fulfillment and flow, and a dependent variable of game satisfaction. The data were collected from 438 users of mobile game and were used for analysis. Based on the survey results, we found the followings: (1) Immediate connectivity, enjoyment, relationship, early adopter tendency, and competitiveness affect self-fulfillment, and self-fulfillment affects the flow. (2) Enjoyment and competitiveness affect self-fulfillment, flow, and game satisfaction simultaneously.

• Journal of Digital Policy
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• v.2 no.1
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• pp.1-7
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• 2023

In China, commercial banks have launched mobile banking one after another, and the homogeneous products make the competition of mobile banking extremely fierce. Mobile banking monthly active users (MAU) is an important indicator to evaluate the operation results of mobile banking. How to improve mobile banking monthly active users is a problem faced by commercial banks. The purpose of this study is to explore strategies to increase monthly active customers of mobile banking with the help of vending machines. This research is carried out through the literature method and case method. The research results show that the use of vending machines can not only effectively increase the monthly active customers of mobile banking, but also realize the differentiation strategy to occupy the mobile banking terminal market. At the same time, this study is helpful and instructive for commercial banks to develop their business.