• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5669-5684
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• 2018

The new mobile edge network architecture has been required for an increasing amount of traffic, quality requirements, advanced driver assistance system for autonomous driving and new cloud computing demands on highway. This article proposes a hierarchical cloud computing architecture to enhance performance by using adaptive data load distribution for buses that play the role of edge computing server. A vehicular dynamic cloud is based on wireless architecture including Wireless Local Area Network and Long Term Evolution Advanced communication is used for data transmission between moving buses and cars. The main advantages of the proposed architecture include both a reduction of data loading for top layer cloud server and effective data distribution on traffic jam highway where moving vehicles require video on demand (VOD) services from server. Through the description of real environment based on NS-2 network simulation, we conducted experiments to validate the proposed new architecture. Moreover, we show the feasibility and effectiveness for the connected car media service on highway.

• Journal of Distribution Science
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• v.12 no.11
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• pp.85-100
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• 2014

Purpose - Recently, the prevalence of high-speed mobile communication technology (4G) and mobile devices (smart phones, tablet PC, etc.) is leading innovative changes across all fields in society as well as business environments. Furthermore, a diversified mobile application service has spread rapidly through mobile devices such as smart phones and tablet PCs. Accordingly, the traditional E-government services paradigm has rapidly changed into mobile intelligence. To identify the influencing factors on the using intention of G4C smart app services, based on previous studies, the variables that influence using G4C smart app services are defined; these are user cognitive factors (perceived usefulness, perceived easiness), user characteristics factors (user innovativeness, self-efficiency, social influence), service quality factors (convenience, interactivity, accessibility), and system quality factors (instant connectivity, safety). Research design, data, and methodology - This is designed not only to collect data with a questionnaire survey (9/22/13~10/23/13) but also to test hypotheses with SEM by SPSS 21.0 and AMOS 21.0 in both Korea and China. All items are used with Likert 5 scales. A total of 643 questionnaires (Korea 318, China 325) are used. Results - The perceived usefulness and perceived easiness in user cognitive factors have positive influence on using intention. The user innovativeness, self-efficiency, and social factors in user characteristics factors have positive influences on using intention. The convenience, interactivity, and accessibility in service quality factors have positive influences on both reliability and using intention. Safety in system quality has positive influence on both reliability and using intention. Reliability has positive influence on using intention. The control variables (Korea and China) affect its control hypothesis. Strategies and implications are suggested to assist the public using the intention of smartphone's e-government services based on the results of the empirical analysis. The mobile application service can be considered a new emergence of the paradigm just like the government's on-line portal websites appeared in the past. Under this prevailing situation of mobile smart devices, to promote the success of e-government mobile APP services, accurate analysis and understanding of users should precede anything, to provide services to grasp and satisfy users' desire properly. Conclusions - This study proposes implications to help E-governmental officers and companies make strategies. First, this is expected to give some information on the understanding and knowledge regarding the process of G4C smart APP service based on the empirical study. Second, this helps to make future policies and ways about E-government G4C smart APP service. Third, it is proved that super speed mobile communication technology and devices including phones will be crucial to change the structure of E-government services in 2-3 years. Fourth, it is necessary to increase the trust and using intention of users. Fifth, considering what type of environment users are placed in, to present proper public information matching their inclination, is important. Finally, various ways of experiencing service to explore potential users and ceaseless public relations are required.

• Journal of Internet Computing and Services
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• v.12 no.1
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• pp.99-110
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• 2011

Mobile environments rapidly changing and digital convergence widely employed, mobile devices including smart phones have been playing a critical role that changes users' lifestyle in the areas of entertainments, businesses and information services. The various services using mobile devices are developing to meet the personal needs of users in the mobile environments. Especially, an LBS (Location-Based Service) is combined with other services and contents such as augmented reality, mobile SNS (Social Network Service), games, and searching, which can provide convenient and useful services to mobile users. In this paper, we design and implement the prototype of mobile personal assistant (PA) agents. Our personal assistant agent helps users do some tasks by hiding the complexity of difficult tasks, performing tasks on behalf of the users, and reflecting the preferences of users. To identify user's preferences and provide personalized services, clustering and classification algorithms of data mining are applied. The clusters of the log data using clustering algorithms are made by measuring the dissimilarity between two objects based on usage patterns. The classification algorithms produce user profiles within each cluster, which make it possible for PA agents to provide users with personalized services and contents. In the experiment, we measured the classification accuracy of user model clustered using clustering algorithms. It turned out that the classification accuracy using our method was increased by 17.42%, compared with that using other clustering algorithms.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.585-588
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• 2002

Grid provides integral ing system that enables to use distributed computing resource and services as adapts traditional infrastructures to overcome the distributed computing environments. But, computing today is moving away from a restriction of the desktop, becoming diffused into our surrounding and onto our personal digital devices. In such mobile computing environments, users expects to access resource and services at any time from anywhere in such Mobile-Grid computing. This expectation results security issues, since the computing environments is expanded. This paper describes the security challenges in Mobile-Grid computing, explaining why traditional security mechanism fail to meet the demands of these environments. This paper describes policy driven security mechanism enabled entity to use service and data in trust Mobile-Grid environments and a set of security service module that need to be realized in the Mobile-Grid security architecture presents a set of use pattern that show hew these modules can be used for billing service in a secure Mobile-Grid environments.

• Journal of Computing Science and Engineering
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• v.3 no.4
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• pp.238-259
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• 2009

In this paper we discuss personal data management with mobile devices, an activity requiring the composition of services offered by standard suites of applications. We propose a data model and an interface model that allows users to define activities, tasks and services, to navigate among them according to the evolution of the personal situation as perceived and interpreted by the users themselves. The interface model acts as a lens exploring the situation, zooming into the details, covering different areas of the personal data, supporting the user in the role of a composer of personal services.

• Journal of Information Technology Services
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• v.7 no.2
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• pp.197-221
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• 2008

This study is to identify quality factors having influence upon mobile internet service performance theoretically, derive the research model and the hypotheses concerning the cause and effect relationship between these factors and service performance and then analyze them empirically. In order to enhance the model's explanation power, trust and cognitive engagement as interviewing variables are included in the model. The theoretical background of this study was brought from relevant literature in the areas of the theory of reasoned action(TRA). technology acceptance model(TAM), product selection model, cognitive absorption theory and etc. The research model and hypotheses were statistically investigated and analysed through convergent and discriminant validity test, reliability test, and path analyses by means of statistical packages SPSS(12.0) and LISREL(8.72). For these empirical analyses. data were collected through the field survey of 373 users who were willing to continuously use the mobile internet services. Based on the results of the analyses, theoretical and practical significance and future study direction were suggested. The results of this study will be helpful to giving a guideline to companies such as mobile telecom, mobile contents provider and mobile handset manufactures when they have to establish the mobile Internet service marketing strategies.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.1
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• pp.71-80
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• 2013

Due to the increased use of mobile devices, there is a lot of discussion on mobile accessibility. Mobile accessibility means that everyone, who includes the disabled, the elderly people, can easily use the functions of mobile devices. In this paper, we presented and implemented a mobile interface using a speech I/O APIs to improve the accessibility. The proposed interfaces are implemented on Android platforms and they used speech recognition and text-to-speech APIs supported as built-in services. In addition, to facilitate the internet access for visually impaired or blind people, we also implemented the web browsing application (web reader).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.358-362
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• 2004

According to the rapid advance of computer and communication techniques, the request of mobile internet services is highly increasing. However, the main obstacles for mobile vector map service environments, are large data volume and narrow wireless bandwidth. Among the many possible solutions, spatial data compression technique may contribute to reduce the load of bandwidth and client response time. This thesis proposes two methods for spatial data compression. The one is relative coordinates transformation method, and the other is client coordinates transformation method. And, this thesis also proposes the system architecture for experiments. The two compression methods could be evaluated the compression effect and the response time.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.11
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• pp.4268-4290
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• 2015

Future mobile communications face enormous challenges as traditional voice services are replaced with increasing mobile multimedia and data services. To address the vast data traffic volume and the requirement of user Quality of Experience (QoE) in the next generation mobile networks, it is imperative to develop efficient content distribution technique, aiming at significantly reducing redundant data transmissions and improving content delivery performance. On the other hand, in recent years cloud computing as a promising new content-centric paradigm is exploited to fulfil the multimedia requirements by provisioning data and computing resources on demand. In this paper, we propose a cooperative caching framework which implements State based Content Distribution (SCD) algorithm for future mobile networks. In our proposed framework, cloud service providers deploy a plurality of cloudlets in the network forming a Distributed Cloud Service Network (DCSN), and pre-allocate content services in local cloudlets to avoid redundant content transmissions. We use content popularity and content state which is determined by content requests, editorial updates and new arrivals to formulate a content distribution optimization model. Data contents are deployed in local cloudlets according to the optimal solution to achieve the lowest average content delivery latency. We use simulation experiments to validate the effectiveness of our proposed framework. Numerical results show that the proposed framework can significantly improve content cache hit rate, reduce content delivery latency and outbound traffic volume in comparison with known existing caching strategies.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.8
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• pp.1459-1464
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• 2006

There are two approaches to construct mobile GIS, Vector and Raster methods, according to the map data transformation format from server to mobile client. Each method requires a different implementation architecture of server and client modules for mobile map services. And each have advantages and disadvantages at the different aspects. This thesis implements these two approaches, thus, compares the each merits, by experiments. They include the transmission performance, map quality, and so on.