• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.6
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• pp.652-662
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• 2016

This paper proposes a user mobility management scheme which supports seamless service even if a user changes his accessing terminal in service in IP-based convergence network. Most of ongoing researches concerning mobility management as well as the existing mobility schemes have been focused to support terminal mobility. It is limited to support a variety of mobility types such as user mobility. The proposed scheme uses the mapping relationship between UID(User Identifier), user specific identifier and TID(Terminal Identifier), specific terminal identifier and forms packet address with user specific permanent 3 layer address for session continuity in case of user mobility. We numerically analyze and compare handover signaling cost between the existing user mobility scheme and the proposed scheme. The result shows that the proposed scheme has lower handover signaling cost than the existing one, [1].

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.1
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• pp.25-34
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• 2010

The IEEE 802.16-2004 standard has a security sub-layer in the MAC layer called, Privacy Key Management (PKM). However, several researches have been published to address the security vulnerabilities of IEEE 802.16-2004. After the IEEE 802.16-2004 standard, a new advanced and revised standard was released as the IEEE 802.16e-2005 amendment which is foundation of Mobile WiMAX network supporting handoffs and roaming capabilities. PKMv2 in Mobile WiMAX includes EAP authentication, AES-based authenticated encryption, and CMAC or HMAC message protection. However, Mobile WiMAX still has a problem of security architecture such as a disclosure of security context in network entry, a lack of secure communication in network domain, and a necessity of efficient handover supporting mutual authentication because Mobile WiMAX security has mainly concentrated on between SS and BS communication. Based on the investigation results, we propose a novel mobile WiMAX security architecture, called RObust and Secure MobilE WiMAX (ROSMEX), to prevent the new security vulnerabilities.

• 대한공업교육학회지
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• v.33 no.2
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• pp.287-299
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• 2008

HTTP is one of the most widely used protocols of the WWW. Currently it uses TCP as the transport layer protocol to provide reliability. The HTTP uses separate TCP connection for each file request and adds unnecessary head-of-line blocking overhead for the file retrieval. The web application is short sized and affected by the increased handover latency of TCP in wireless environment. SCTP has attractive features such as multi-streaming and multi-homing. SCTP's multi-streaming and multi-homing avoid head-of-line blocking problem of TCP and reduce handover latency of TCP in wired and wireless environment. Mean response time is the important measure in most web application. In this paper, we present the comparison of mean response time between HTTP over SCTP with that of HTTP over TCP in wired and wireless environments using NS-2 simulator. We measured mean response time for varying packet loss rate, bandwidth, RTT, and the number of web objects in wired environment and mean response time and packet loss rate for varying moving speed and region size in wireless environment. Our experimental result shows that SCTP reduces the mean response time of TCP based web traffic.