• The Journal of Society for e-Business Studies
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• v.8 no.1
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• pp.71-83
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• 2003

Nowadays on-line services based on Internet are being popularized and there are lots of E-Commerce applications using Internet. So we can use lots of information on anytime. To maximize the convenience of the network, the platform of the service is moving from E-Commerce to M-Commerce. In this paper we developed the application system for mobile environment. Therefore applicants can apply their applications and see the competition rate of the applying departments anytime and anywhere even if in the network disconnection regions. And we can manage more economically the application system because we use the network only the time when we syncronize the mobile device to mobile server.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.7
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• pp.1448-1458
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• 1997

In this paper the reverse link of the GLOBALSTAR-the representative CDMA LEO satellite system and LEO mobile satellite channel are developed by the SPW software simulation tool. And the performance of the system is evaluated. GLOBALSTAR is designed to give cellular-type service to hand-held user terminals through a constellation of 48 LEO satellites in circular orbites with 1414 Km altitude. Since LEO mobile satellite system communicates with mobile unit, it is suffered from severe multipath fading and shadowing. The fast mobility of LEO satellites makes the channel condition time vering. So, the LEO mobile satellite channel is different from land mobile channels. In this unique LEO satellite channel, it is shown that the performance of the GLOBALSTAR reverse link is varied according to the elevational angle, but this variation is overcome by satellite path diversity.

• Journal of Digital Convergence
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• v.4 no.2
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• pp.87-96
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• 2006

This study first tries to investigate factors that determine the quality of mobile game contents. Based on the information and information system-related studies, our research proposes to show the relationships among the quality of mobile game contents, the level of perceived easy of use and the perceived usefulness. Mobile game contents service providers can get insight on factors that should be considered to improve the quality of contents services. Also, the research findings provide a clue on the success of mobile game service.

• 한국디지털정책학회:학술대회논문집
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• 2006.06a
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• pp.409-417
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• 2006

This study first tries to investigate factors that determine the quality of mobile game contents. Base on the information and information system-related studies, our research proposes to show the relationship among the quality of mobile game contents, the level of perceived easy of use and the perceived usefulness. Mobile game contents service providers can get insight on factors that should be considered to improve the quality of contents services. Also, the research findings provide a clue on the success of mobile game service.

• Journal of Information Technology Services
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• v.15 no.1
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• pp.289-298
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• 2016

There are continuos tendencies toward that foreign tourists increase. Since 55% of them visit Korea without data communication for saving the communication costs, they can not utilize a variety of O2O services through QR/NFC/Beacon. There have been some researches to provide a smart map service based on the micro webpage technology even without data communication. But, they do not suggest how the templates are retrieved into their smart-phones. In this paper, we describe a mobile tourist information system for those who have no data communication. We utilize the micro webpage technology to develop a system for market promotion, shopping goods, and tourist maps. What matters in the micro webpage techniques is that the templates should be already downloaded to the users' smart phones before using it. The preceeded research did not mention the problem. We suggest a scheme that tourists obtain the tremplates in the information offices on the spot through Wi-Fi. We describe the details of the system, and evaluate the data overhead of templates and the time to be downloaded. We show that the overheads are endurable, which means that the system would be working well.

• The KIPS Transactions:PartC
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• v.10C no.7
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• pp.943-954
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• 2003

The mobile telecommunication system has been growing exponentially after 1990s due to the high population in a city and the growth of mobile user. In this time, the current mobile system mainly concentrates on the voice communication. However, in the next generation, mobile users want to get very diverse services via mobile terminal such as the Internet access, web access, multimedia communication, and etc. For this reason, the next generation system, such as the UMTS (Universal Mobile Telecommunication Services) system, has to support the packet data service and it will play the major role in the system. By the way, since the Web service is based on TCP, most of the Internet traffic TCP traffic. Therefore, efficient transmission of TCP traffic will take very important role in the performance of packet data service. There are many researches about improving TCP performance over wireless network. In those schemes, the UMTS system adapts the link layer retransmission scheme. However, there are rarely studies about the exact performance of the link layer retransmission scheme in the face of dynamic changes of wireless environment over the UMTS system. The dynamic changes of wireless environment, such as wireless bandwidth, can degrade TCP performance directly. So, in this paper, we simulate and analyze the TCP performance in the UMTS system with dynamic wireless environments. Then, we propose a simple scheme for minimizing TCP performance degradation. As a result of simulation, we can find that when wireless environment is changed dynamically, the probability of TCP timeout is increased, and the TCP performance is degraded very much. In this situation, the proposed simple scheme shows good performance. It saves wireless resources and reduces the degradation of TCP performance without large overhead of the base station.

• KIPS Transactions on Software and Data Engineering
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• v.1 no.1
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• pp.19-30
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• 2012

The context aware service is the service to provide useful information to the users by recognizing surroundings around people who receive the service via computer based on computing and communication, and by conducting self-decision. But CAS(Context Awareness System) shows the weak point of small-scale context awareness processing capacity due to restricted mobile function under the current mobile environment, memory space, and inference cost increment. In this paper, we propose a mobile cloud context system with using Google App Engine based on PaaS(Platform as a Service) in order to get context service in various mobile devices without any subordination to any specific platform. Inference design method of the proposed system makes use of knowledge-based framework with semantic inference that is presented by SWRL rule and OWL ontology and Jess with rule-based inference engine. As well as, it is intended to shorten the context service reasoning time with mapping the regular reasoning of SWRL to Jess reasoning engine by connecting the values such as Class, Property and Individual which are regular information in the form of SWRL to Jess reasoning engine via JessTab plug-in in order to overcome the demerit of queries reasoning method of SparQL in semantic search which is a previous reasoning method.

• The Journal of the Korea Contents Association
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• v.9 no.1
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• pp.131-138
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• 2009

This paper is about adult certification on Mobile RFID Service Environments coming through the combination of RFID(Radio Frequency IDentification) technology, as the core technology of ubiquitous environments, and mobile telecommunication technology. To overcome the shortcoming of simple adult certification on current internet, we suggest a framework for content-based classification and propose an adult certification system using it. At first, we explain conventional methods for adult certification, and show a criteria of content-based classification for preventing an exposure of adult contents from minors. Additionally, we describe data structure and system for the proposed adult certification on mobile RFID environment, and finish it with concluding remarks.

• ETRI Journal
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• v.19 no.3
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• pp.186-201
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• 1997

In this paper, a home location register (HLR) for CDMA mobile communication system (CMS) is introduced. It stores the mobile station (MS) subscribers locations and supplementary service information. Call processing procedures for HLR are developed to receive and store subscriber's location coming from mobile exchange (MX) during the location registration, and to transfer subscriber's location and supplementary service information to the MX during the mobile-terminated call setup. For fast call processing by increasing database access speed, a memory-resident database management system is devised. For Easy and secure HLR operation, administration and maintenance functions and overload control mechanisms are implemented. Designed HLR hardware platform is expandable and flexible enough to reallocated software blocks to any subsystems within the platform. It is configurable according to the size of subscribers. An authentication center (AC) is developed on the same platform. It screens the qualified MS from the unqualified. The calls to and from the unqualified MS are rejected in CMS. To authenticate the MS, the AC generates a new authentication parameter called "AUTHR" using shared secret data (SSD) and compared it with the other AUTHR received from the MS. The MC also generates and stores seed keys called "A-keys" which are used to generate SSDs. The HLR requirements, the AC requirements, software architecture, hardware platform, and test results are discussed.

• Journal of Internet Computing and Services
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• v.8 no.3
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• pp.85-98
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• 2007

In distributed computing paradigm, mobile surrogate systems have not gained wide acceptance because of security concerns that have not been suitably addressed yet. Currently even the widely used Grid middleware, Globus, does not have a host authentication mechanism, which makes it hard to provide high performance Grid computing capabilities to mobile clients. In this paper, a mobile Grid service framework is designed and implemented in order to provide Grid services to mobile host such as PDA. The surrogate host-based system allows mobile hosts to be provided with Grid services while moving. The implemented mobile Grid services system has been applied to mobile healthcare system which utilizes Grid computing for ECG signal processing. The presented system framework can be used as a secure enterprise mobile healthcare system for hospital physicians.