• Journal of information and communication convergence engineering
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• v.7 no.2
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• pp.141-147
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• 2009

To initialize and maintain self-organizing networks such as mobile ad hoc networks, address allocation protocol is essentially required. However, centralized approaches that pervasively used in traditional networks are not recommended in this kind of networks since they cannot handle with mobility efficiently. In addition, previous distributed approaches suffer from inefficiency with control overhead caused by duplicated address detection and management of available address pool. In this paper, we propose a new dynamic address allocation scheme, which is based on adaptive partition. An available address is managed in distributed way by multiple agents and partitioned adaptively according to current network environments. Finally, simulation results reveal that a proposed scheme is superior to previous approach in term of address acquisition delay under diverse simulation scenarios.

• Journal of Industrial Technology
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• v.26 no.B
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• pp.207-213
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• 2006

Mobility Anchor points are used for the mobility management in HMIPv6 networks. Currently a mobile node selects the MAP farthest away from itself as a new MAP among available candidates when it undertakes a macro hand off. With this technique, however, the traffic tends to be concentrated at a MAP with the largest domain size and the communication cost increases due to the distance between the mobile node and the MAP. In this work, we propose a novel scheme to select a MAP to minimize the communication cost, taking the mobile node's moving speed and data rate into account. To come up with the scheme we analyses the communication analyses the communication cost into the binding update cost and the data packet delivery cost, and derive an equation representing the optimal MAP domain size to minimize the total cost.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.195-196
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• 2006

Frame synchronization is an critical factor for an effective operation of OFDM (orthogonal frequency division multiplexing) based communication systems. In this paper, we present and analyze an efficient frame synchronization method based on m-sequence for OFDM-based mobile multimedia communication systems. The cyclic extension preceding OFDM frames is of decisive importance for this method. The m-sequence is added directly to cyclic extension signal in the time domain. By utilizing the autocorrelation characteristics of m-sequence, efficient frame synchronization can be achieved. And we also consider frequency offset estimation simultaneously. The proposed frame synchronization method can be applied to the OFDM-based mobile multimedia communication systems.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.580-582
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• 2012

네트워크 기반의 이동성 관리 프로토콜인 PMIPv6(Proxy Mobile IPv6)에서 방송이나 비디오 스트리밍과 같은 서비스를 제공할 때 멀티캐스트 방식을 이용하여 데이터 패킷을 전송하는 기법이 제안되었다. 제안되었던 기법은 MN(Mobile Node)이 핸드오버할 때 nMAG(new Mobile Access Gateway) 내에 같은 멀티캐스트 멤버인 또 다른 MN이 존재할 경우를 고려하지 않았다. 본 논문에서는 같은 멀티캐스트 멤버인 MN이 존재할 경우 버퍼링된 패킷들의 중복 전송을 막는 기법에 대해 제안한다. 이 후 MN이 nMAG로 핸드오버했을 때 같은 멀티캐스트 멤버를 가진다면 버퍼링된 패킷을 현재 핸드오버한 MN에만 포워딩하여 중복 전송되는 것을 방지한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.858-861
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• 2011

최근 VoIP 서비스는 IP 네트워크의 안정화를 기반으로 국내 기업 Legacy PSTN 시장을 빠르게 대체해 가고 있다. 그러나 VoIP 서비스는 기존 인터넷망에서 발생 할 수 있는 보안 취약성 뿐 아니라 인터넷 전화 트래픽의 통과 문제 및 VoIP 스팸이나 도청 같은 기존에 없었던 새로운 이슈들을 발생 시키고 있다. 특히 SIP 인증 취약점을 이용한 Fraud Call 공격은 VoIP 서비스 사용자로 하여금 원하지 않은 호 및 과금을 대량 발생 시키는 공격기법으로 최근 기업의 피해사례가 늘어 나고 있다. 본 논문은 Fraud Call의 공격 기법을 분석하고, 호 인증 측면에서의 보안적 대응방안을 기술하고자 한다.

• Proceedings of the CALSEC Conference
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• 2005.03a
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• pp.125-129
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• 2005

The recent push for healthcare reform has caused healthcare organizations to focus on ways to streamlined processes in order to secure high quality care as well as reducing costs. Healthcare enterprises involve complex processes that span diverse groups and organizations. These processes involve clinical and administrative tasks, large quantities of data, and large number of patients and personnel. We propose the mobile-based workflow system of passable communication as an important factor in the B2B healthcare. Based on the above proposal the workflow system of business process was designed and implemented on the basis of Java, UML and XPDL.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.10 no.2
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• pp.21-30
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• 2000

본 논문에서는 이동통신환경의 특징과 기존의 키분배 프로토콜들에서 발생할 수 있는 공격들을 프로토콜 수행전 수행중, 수행후로 나누어서 살펴보고 이를 기반으로 이동통신환경에 적합한 키분배 프로토콜 설계에 필요한 요구사항 들을 제시한다 또한 제시된 요구사항을 기반으로 이동통신환경에 적합한 상호인증을 제공하는 키분배 프로토콜을 제안하고 제안한 프로토콜을 분석한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.5
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• pp.2029-2046
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• 2016

Energy consumption is an important index in mobile ad hoc networks. Data packet transmission increases among nodes, particularly in big data communication. However, nodes may be unable to transmit data packets because of energy over-consumption. Consequently, information may be lost and network communication may block. While opportunistic network is a kind of mobile ad hoc networks, researchers do not focus on energy consumption in opportunistic network communication. This study proposed an effective sensor energy supply scheme that can be applied in opportunistic networks. This scheme considers nodes sensor requests and communication model. In this scheme, nodes do not only accomplish energy supply in communication, but also extend communication time in opportunistic networks. Compared with the Spray and Wait algorithm and the Binary Spray and Wait algorithm in simulations, the proposed scheme extends communication time, increases data packet transmission, and accomplishes energy supply among nodes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.1B
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• pp.61-70
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• 2007

An interworking translator for IPv6 and IPv4 services can be defined as an intermediate component between a native IPv4 host and a native IPv6 host to enable direct communication between them without requiring any modifications to the hosts. But if the host is a mobile node, triangle routing problem occurs, since Mobile IPv4 allows mobile node to roam transparently in my network. In this situation, mobile node must notify transfer information to its own home agent and correspondent node in IPv6 network. But current NAT-PT does not permit mobility header translation. Therefore, NAT-PT does not support efficient communication between Mobile IPv4 and Mobile IPv6. In this paper, we propose a mobility header conversion mechanism to resolve the triangle routing problem between Mobile IPv4 and Mobile IPv6.

• 전자공학회논문지 IE
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• v.47 no.4
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• pp.48-52
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• 2010

Recently, WiBro service as a mobile internet has been being extended. The market of wireless data communication has been being extended rapidly due to the increase of mobile data communication service supply such as smart-phone, WiBro service and so on. As the result, security is also emphasized in the mobile Internet In this paper, we propose the methods that tighten up security in the upcoming Enterprise Mobile-VPN service on WiBro network.