• Journal of Advanced Navigation Technology
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• v.19 no.6
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• pp.601-606
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• 2015

Recently wireless data services have widely spread on various multimedia devices such as smart phones and tablets. Existing wired data services have been replaced by wireless data services using mobile devices. Especially domestic mobile devices supporting both Wireless-Fidelity (Wi-Fi) and long term evolution (LTE) services have increased steadily. While Wi-Fi network is provided free of charge, LTE network is offered to pay for. Therefore, mobile devices provide smart network switch to support both preferred Wi-Fi and LTE networks. However, such handover and roaming between Wi-Fi and LTE networks can cause data connection stop in spite of charged data services. This paper has proposed the method to overcome data connection stop for guaranteeing seamless data service during handover and roaming procedures between networks.

• Journal of Digital Convergence
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• v.12 no.11
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• pp.133-139
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• 2014

This study has designed the system that can manage the amount of exercise required for health management, viewing the health management courses which are currently being operated, register the desire courses and verifying the registered schedules and monthly health performances at a glance by using a mobile application. The advantage of health club management system is automatically transmits the daily exercise information to the server without a separate sensor through a simple QR scanning using a smart phone. Since the overall operating requirements of services and various facilities of health club is transmitted as the data to the remote server through a smart phone, users of various levels including workers, students, housewives, etc can easily access and use the health club management system using the WiFi, LTE, 3G, etc.

• Proceedings of the Korea Contents Association Conference
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• 2011.05a
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• pp.7-8
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• 2011

최근 무선통신의 발전과 스마트 폰 사용자의 급격한 증가로 인하여 멀티미디어 콘텐츠에 대한 관심과 요구가 급속히 증대되고 있다. 이를 수용하기 위한 이동통신 시스템 환경 역시 급속도로 변하고 있으며, 그중 LTE 시스템에 대한 관심과 개발이 진행되고 있는 상황이다. 이에 따라 개발단계부터 안정화단계까지 해당 시스템의 프로토콜 검증과 분석을 위한 분석기의 필요성이 대두되고 있다. 본 논문에서는 LTE 프로토콜과 연동 메시지를 XML 메타데이터로 기술한 에이전트-서버 구조의 프로토콜 분석기를 제안한다. 제안하는 프로토콜 분석기는 LTE 시스템에 최적화된 프로토콜 분석이 가능하고 연동 규격 변경시에도 XML 메타데이터 수정만으로 적용가능하다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.1
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• pp.115-123
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• 2015

As LTE service and smartphone are emerging as the mainstream of mobile communications market, the value and importance of mobile data service has been further increased. MNO(mobile network operator)s already recognized the data service as essential market needs, and have appealed to consumers based on various satisfaction elements of data service such as faster transmission speed, expended data volume provided as default, and introduction of unlimited plan. So, in the smartphone market where has been mature, investigating what service attributes affect users' selection of data service is very meaningful from the perspectives of both the industry and the academic. Under this background, this study explores determinants influencing consumer's choice for mobile data service and analyzes relative importance of the attributes among different type of users. The findings of this study makes us extend our understanding of consumer characteristics and their service needs in data service centric era, and it provides some implications for establishing telecommunications policies and business strategies.

• Journal of Digital Convergence
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• v.16 no.1
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• pp.281-286
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• 2018

In recent days, when the development in smartphones has made it common to operate objects by using them, this study aimed to present a guideline for the UI/UX designs for applications which are necessary for operating various objects through the wireless communication technology. To suggest the application guideline, existing object control application case studies were analyzed, and based on this investigation the object control application UI/UX design guidelines were proposed. This study classified the types of wireless connections used by smartphones (LTE, Wi-Fi, Bluetooth, NCF, RFID) and analyzed the necessary design factors for operating objects by each type. Based on such analysis, this study presented the design sequence, factors, and methods for the UI/UX guidelines of applications. First, the method of connection was selected; second, the control device was selected. This new direction for designing smartphone applications for operating objects will likely help systemize the design process and enable the user to operate the object more intuitively. In future research, case studies will be designed applying the guidelines suggested from this study.

• Proceedings of the Korean Society of Computer Information Conference
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• 2016.07a
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• pp.237-238
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• 2016

대부분의 작업환경에서는 여러 가지 위험요소로 인한 안전사고가 자주 발생한다. 추락이나 작업환경의 붕괴 등 안전사고 발생시, 작업자가 관리자에게 응급상황을 전해야하지만, 사고로 인해 작업자가 원활하게 몸을 사용하지 못하는 경우에는 응급상황을 전달하는데 문제점이 발생한다. 본 논문에서는 이러한 문제를 해결하기 위해서 블루투스로 스마트폰에 응급상황을 전할 수 있는 웨어러블 단말기와 스마트폰의 WI-FI나 LTE망을 사용하여 작업자의 상황을 실시간으로 모니터링 할 수 있는 안전 시스템을 설계한다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.14 no.2
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• pp.140-148
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• 2021

In this paper, we intend to improve the availability by integrating Sonobuoy, the most essential detection system used in anti-submarine operations, with LTE communication of smart devices. Anti-submarine capability to respond to the threat of North Korean submarine forces is becoming increasingly important, and continuous research and development is required. This paper aims to enhance the ability of acoustic tactics by using a military-only LTE communication system installed on a ship, smart devices that can be linked to it, and a multi-static sonobuoy controlled by them. The proposed system can increase the visual effect by not only displaying coordinate values by receiving accurate coordinate information of each sonobuoy to a smart device, but also displaying a marker on a map.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.12
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• pp.20-29
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• 2014

Recently, LTE is preparing to make a new leap forward LTE-A all over the world. As LTE privides high speed service, the role of mobile phones seems to change from voice to data service. According to Cisco, global mobile data traffic will increase nearly 11-fold between 2013 and 2018. Mobile video traffic will reach 75% by 2018 from 66% in 2013 in Korea. However, voice service is still the most important role of mobile phones. Thus, controllability of throughput and low BLER is indispensable for high-quality VoIP service among various type of traffic. Although the maximum AMR-WB, 23.85 Kbps is sufficient to a VoIP call, it is difficult for the LTE which can provide tens to hundreds of MB/s may not keep the certain level VoIP QoS especially in the cell-edge area. This paper proposes a new scheduling algorithm in order to improve VoIP performance after analyzing various scheduling algorithms. The proposal is the technology which applies more priority processing for VoIP than other applications in cell-edge area based on two-tier scheduling algorithm. The simulation result shows the improvement of VoIP performance in the view point of throughput and BLER.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.8
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• pp.915-919
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• 2014

Since smart phones are widely used globally, the demand for high-speed mobile communications are increasing. To accommodate the increased communication demand, the next-generation mobile communication services such as LTE-Advanced are deployed. In the LTE-Advanced base stations, the base station schemes of Digital Unit (DU) and Radio Unit (RU) are widely used. Here, the link between DU and RU is called fronthaul link. In the current fronthaul link, a digital optical communication interface is used, which is called Common Public Radio Interface (CPRI). However, the CPRI link cannot support the increased mobile traffic efficiently. Therefore, in this paper, we investigate an alternative technology based on the Radio over Fiber (RoF) to accommodate the increased mobile traffic economically.

• KIPS Transactions on Computer and Communication Systems
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• v.1 no.2
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• pp.109-118
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• 2012

As a result of the prevalence of smartphone, various mobile services became faster by LTE networks. Because many mobile devices are used more wireless services, heavy signaling traffic for authentication could be generated. Authentication is an important factor in wireless networks to identify devices; it is the start of wireless networks. This paper analyzes previous patterns for more effective authentication in accessing of another external networks. We propose a fast authentication scheme for minimizing of signaling cost between the authentication server and external networks. And we calculate the rate of authentication occurrence in LTE networks using mathematical modeling as well as the change of signaling cost for authentication in various network environments. Finally, we calculate the optimized number of authentication data and show the effectiveness for authentication signaling costs.