• Journal of Korea Multimedia Society
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• v.12 no.11
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• pp.1509-1520
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• 2009

Contrary to ubiquitous environments, indoor computing environments like home network doesn't support user mobility. This paper suggests UPnP A/V multimedia system using prediction of mobility for adaption of seamless multimedia service. The multimedia system enables indoor mobile users to play multimedia contents by transferring the current session to an adjacent device automatically. The system represents users' contextual information by Five Ws and One H model, and predicts user's movements by using contextual information and transitions of locations. The prediction basically includes multiple locations so that it improves accuracy of prediction. We evaluated the suggested system using in accuracy of prediction, time for prediction, handover time for service, and the system showed that adapt ion of seamless multimedia service was enabled by using prediction of mobility on mobile user.

• Journal of KIISE:Information Networking
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• v.37 no.1
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• pp.66-71
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• 2010

This paper proposes mobility management schemes providing Internet session continuity to moving vehicles in the V2I (Vehicle-to-Infrastructure) environment of the vehicular communication networks. Since PMIPv6 is localized mobility management protocol, PMIPv6 can not be directly applied to the vehicular communication network requiring global mobility coverage. Therefore, in this paper, we derive two scenarios of applying PMIPv6 to vehicular communication network environment and propose PMIPv6-based global mobility management schemes for those scenarios. Through simulations, we show that the proposed schemes can significantly decrease the Internet service discontinuity.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.1
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• pp.75-82
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• 2003

We can foresee the rapidly growing of users by development of VoIP service what can transmit a audio traffic with low cost among a lots application using internet. VoIP needs a standardized protocol that is able to do signaling for offering high quality of services such as mobility, universal number, multiparty conference, voice mail, automatic call distribution. At the present time, a base composition elements of SIP(Session Intiation Protocol) are developing for offering VoIP based SIP in the inside and outside of the country, because SIP of IETF which has a strength from 'fast connection', 'parsing' & 'easy to compile' points of view. This paper suggests a type of Hybrid SIP Server for providing some services as 'a reducing load of SIP server that process a request method from users', 'efficiency of managing networks', 'offering services to many users'.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.1
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• pp.219-236
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• 2014

In this paper, we propose a novel Proxy Mobile IPv6 network bandwidth-efficient handoff scheme. MN are classified into slow and fast one. At first MN should be registered in the microcell for bandwidth efficient handoff scheme. microcell is overlapped to handle the overflow session request which is nested. Overflow session request in macrocell requests to go back from the boundary of the microcell to new microcell. If idle session traffic is in a cell, it is requested by the target microcell. Analysis model was developed, an existing session of the session blocking probability and forcing termination probability of the session request have improved considerably. If the total traffic load of the system is not very large, the proposed scheme has the best bandwidth efficiency and provides better quality of service (QoS) to MN without costs of a lot of processing on the system.

• The Journal of Korean Association of Computer Education
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• v.13 no.1
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• pp.53-64
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• 2010

In this paper, we tried to enable a mobile device as a resource to access to mobile grid networks. By advanced Internet techniques, the use of mobile devices has been rapidly increased. Some researches in mobile grid computing tried to combine grid computing with mobile devices. However, according to intrinsic properties of mobile environments, mobile devices have many considerations, such as mobility management, disconnected operation, device heterogeneity, service discovery, resource sharing, security, and so on. To solve these problems, there are two trends for mobile grid computing: a proxy-based mobile grid architecture and an agent-based mobile grid architecture. We focus on a proxy-based mobile grid architecture with IP-paging, which can easily manage idle mobile devices and grid resource status information. Also, we use SIP(Session Initiation Protocol)to support mobility management, mobile grid services. We manage variation of mobile device state and power by paging cache. Finally, using the candidate set and the reservation set of resources, we perform task migration. The performance evaluation by simulation, shows improvement of efficiency and stability during execution.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.223-228
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• 2008

Recently, various types of wireless access networks, such as WLAN, WiBro and HSDPA, etc, have been successfully deployed by commercial service providers (i.e., KT, KTF). In this situation, there are many efforts to provide high quality of services to guarantee seamless mobility between heterogeneous networks. The IP layer mobility protocols are efficient mechanisms to provide seamless mobility between IP based heterogeneous networks as well as homogeneous networks. However, to apply IP mobility protocols in real heterogeneous networks (i.e., WiBro and HSDPA), we must consider not only the basic features of techniques of wireless access networks (i.e., Data rate, Coverage, Quality of Service) but also the problem of real environment of service provider (i.e., Expanse cost to change the access network). Due to this reason, it is difficult to satisfy required conditions by using only one IP mobility protocol in real heterogeneous networks. Therefore, in this paper, we propose an efficient mobility protocol to solve the complex problems that are occurred in real heterogeneous networks. The proposed protocol, so-called, "Hybrid Mobile IP" tries to provide a synergy effect by integrating Client Mobile IPv4 (CMIPv4) and Proxy Mobile IPv4 (PMIPv4), and using the two mobility protocols selectively according to the situation of real heterogeneous networks.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.12
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• pp.9-16
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• 2011

Most of the current mobility management protocols such as MIPv4/6 and its variants standardized by the IETF do not support global seamless handover. This is because they require comprehensive changes of the existing network infrastructure. In this article, we propose a simple mobility management protocol (SMMP) which can support global seamless handover between homogeneous or heterogeneous wireless networks. The idea is that the SMMP employs separate location management function as done in SIP to support global user and service mobility. In addition, the bidirectional tunnels are dynamically constructed to support seamless IP mobility by extending the IEEE 802.21 MIH standards. The detailed architecture and functions of the SMMP have been designed. Finally, the simulation results, using NS-2, show that the proposed SMMP outperforms the existing MIPv6 and HMIPv6 in terms of handover latency, packet loss, pear signal noise ratio (PSNR).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.681-682
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• 2012

The PDP using three functions provides active network control on policy based networks so that it processes the mobile terminal session control, mobility and QoS of network service. In this paper we consider PDP implementation.

• Electronics and Telecommunications Trends
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• v.17 no.3 s.75
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• pp.41-52
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• 2002

서브 시스템의 구조와 기능 요소 및 관련 신호 프로토콜에 대해 기술하고 있다. IM 서비스란 이동가입자에게 하부에 IP 전송 프로토콜을 기반으로 하는 다양한 형태의 패킷 서비스들을 동시에 제공하는 것을 말한다. 이를 위해 3GPP에서 제시하고 있는 논리적인 ALL IP 망 구조는 IM CN 서브시스템을 포함하고 있는데, IM CN 서브시스템의 중요한 기능 요소로는 Call Session Control Function(CSCF)와 Home Subscriber Server(HSS) 등이 있다. CSCF는 가입자가 위치하고 있는 망에 따라서 가입자의 세션과 서비스를 제어한다. HSS는 가입자의 마스터 데이터베이스로 기존의 3G HLR의 모든 기능과 User Mobility Server(UMS) 기능을 가진다. 본 고에서는 위의 두 기능 요소들의 기능과 상호 간의 시그널링 프로토콜을 최신 동향을 기반으로 분석하고 기본적인 시그널링 절차도 기술한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.925-926
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• 2009

All IP 기반 BcN(Broadband Convergence Network)의 발전과 단말 기술의 발전은 언제 어디에서나 임의의 단말을 통해 웹과 같은 데이터 서비스, 통화 서비스, 스트리밍 서비스를 동시에 이용하는 것을 가능하게 하였다. 주로 TV를 통한 멀티미디어 콘텐츠 서비스가 PC와 모바일 단말 상에서도 가능해 졌으며, PC를 중심으로 사용되던 웹 기반 서비스가 TV와 모바일 단말에서도 사용이 가능해지고 있다. 본 논문에서는 서비스 이용환경을 향상시키기 위해 특정 단말에서 이용 중인 서비스를 다른 단말에서 끊김 없이 이용할 수 있도록 하는 서비스 세션 이동성을 보장하는 메커니즘에 대해서 살펴보고, 웹 기반 서비스의 세션 이동성 보장에 관한 기존 연구를 비교 분석하고, 향후 연구 방향을 정립하고자 한다.