• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.3
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• pp.478-484
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• 2008

When a mobile node moves, MIPv6 operates an authentication process for the new connection. These kinds of frequent binding update and authentication processes cause much traffic and delay the service. To solve this problem, PMIPv6 provides a network-based mobility protocol in order to lessen the load on a mobile node. However, when it is moved from a domain to a domain or in a domain, there still lies a need fDr a new address, so MIPv6's demerit still exists. In IPsec, too, a new negotiation should be made when it is moved to WAN(Wide Area Network). This causes load to the mobile node. In this paper suggests MBB(Make Before Break) system to eliminate disconnections or delays resulted from the address change or renegotiation for security. When the mobile node receives a CoA address, IPsec negotiation gets operated. Its identity is authenticated by sending the identifier used for the prior negotiation to CN(Correspondent Node) through the BID message suggested. After that, negotiation Bets simplified that disconnections can be eliminated, and in the IPsec negotiation, the load on the mobile node can be lessened as well; moreover, two addresses are used for the communication simultaneously, so the probability of packet loss can be reduced.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.5
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• pp.49-56
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• 2004

An Internet draft, named RR(Return Routability) protocol, proposed to IETF mobileip WG, in order to establish an optimal path to MN(Mobile Node) by securely sending the BU(Binding Update) message to CN(Correspondent Node). However, it has some problems with initiating the protocol by the MN: it causes to increases in communication load in the home network, to increases communication delay between MN and CN, and increases in communication load due to unnecessary message exchanges. To resolve the problems, this paper proposes an alternative scheme for the RR protocol in MIPv6. The proposed scheme is devised to start the protocol by HA on receiving the first packet from CN. It decreases the route optimization overhead by reducing the number of BU messages as well as the communication time. Beside these advantages, this scheme provides the same security grade as the original RR protocol.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.287-289
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• 2013

Fast Handover for Proxy Mobile IPv6 (FPMIPv6), a protocol described in RFC 5949, is used to reduce handover latency and minimize packet loss problem occuring in the Proxy Mobile IPv6 (PMIPv6) protocol. However, during the study of implementing FPMIPv6, we found the Out-of-Order Packet (OoOP) problem that occurs in the experiment of FPMIPv6. Since the OoOP is an issue that affects significantly to QoS of the network, in this paper, we analyze the OoOP problem by using network model. The analysis conducts the cause of occurring OoOP problem due to there exist two paths for data transmitted from Correspondent Node (CN) to MN in FPMIPv6.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.1155-1158
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• 2008

MIPv6(Mobile IPv6)는 이동노드(mobile node, MN)의 이동성(mobility)를 고려하여 만들어진 프로토콜로 이동노드와 상대노드(correspondent node, CN)간의 효율적인 통신을 위해 경로 최적화 기능을 제공하며, 이를 통해 두 노드가 홈 링크를 통하지 않고도 직접 통신할 수 있다. 이때 경로 최적화를 위해 바인딩 갱신(binding update)과정을 수행하며, MIPv6는 RR(return routability)를 통해 바인딩 갱신을 보호한다. 하지만 RR을 통한 바인딩 갱신은 거짓된 바인딩 갱신 공격에 취약하다. 본 논문에서는 RR과정의 취약점을 보완하는 HT-RR메커니즘을 제안한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05b
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• pp.1301-1304
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• 2003

Mobile IP는 현재의 인터넷에서 노드가 링크를 변화시킬 때 통신이 지속 될 수 있도록 Mobility를 제공하기 위한 방안이다. Mobile IP는 MN(Mobile Node)가 HA(Home Agent) 와 FA(Foreign Agent) 사이에서 링크가 변화할 매 CN(Correspondent Node)와 지속적인 통신을 할 수 있도록 한다. 그러나 FA에서 FA로 MN이 노드의 위치를 바꿀 때에는 핸드 오프가 발생하여 패킷이 손실 될 수도 있다. 본 논문은 MN이 여러 FA를 이동할 때 발생하는 패킷 손실에 대한 경우를 살펴 이를 해결하기 위한 Seamless 핸드오프(Handoff) 알고리즘을 기술한다.

• The Journal of the Korea Contents Association
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• v.19 no.12
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• pp.346-361
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• 2019

The purpose of this study is to compare perceptions toward multicultural adolescents' career problems between multicultural adolescents and parents with multicultural backgrounds and youth and parents in non-multicultural families and to discuss their differences. For this purpose, the data from 825 respondents were analyzed using correspondent analysis. The results follow as: first, multicultural adolescents tended to agree very much with the difficulties of interpersonal relations, distance from appearance, and economic difficulties while non-multicultural adolescents tended to disagree with. Second, both multicultural and non-multicultural adolescents disagreed with the confusion about identity as Koreans, but parents of non-multicultural adolescents showed a negative perception. Third, in terms of education and institutions, multicultural adolescents recognized the strong need for expanding career education opportunities for multicultural students, supporting employment, strengthening access to career information, and professional help for careers compared to non-multicultural adolescents.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10c
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• pp.340-342
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• 2004

정보통신 기술의 발달로 사용자는 이동간에도 지속적인 인터넷 서비스를 받길 원한다. 이에 이동성 지원을 위한 많은 연구들이 있었다. 이동성 지원을 위한 HMIPV6환경에서 이동노드(Mobile Node)가 새로운 MAP 도메인으로 이동하거나 처음으로 MAP 도메인에 진입할 때 이동 노드는 홈 에이전트(Home Agent)와 상대 노드(Correspondent Node)에게 자신의 바인딩 정보를 갱신 하여야만 한다. 이 때 이동노드는 MAP 도메인 내에서 LCoA와 RCoA를 MAP에게 바인딩을 하고 자신의 HoA(Home Address)를 이용하여 홈 에이전트와 상대노드에게 바인딩 갱신 메시지를 보내어 바인딩 정보를 갱신한다. 본 논문은 이동 노드가 지역 바인딩 갱신(LBU)메시지와 함께 보내는 바인딩 갱신 메시지를 이용하여 MAP가 이동노드 대신 바인딩 갱신 메시지를 보냄으로써 시그널링을 줄이는 방안을 제시하고자 한다.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.1
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• pp.39-49
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• 1995

Stereo vision is useful to obtain three dimensional depth information from two images taken from different view points. In this paper, we reduce searching area for correspondence by using the intra-scanline constraint, and utilize the inter-scanline constraint and the property of disparity continuity among the neighboring pixels for relaxation. Nodes with 3-D stucture are located on the axes of two views, and have matching possibility of correspondent pixels of two images. A matching is accepted if a node at the intersection of the disparity axes has the greatest matching possibility. Otherwise, the matching possibility of the node is updated by relaxation with the cooperation of neighboring nodes. Further relaxation with competition of two views is applied to a matching possibility of randomly selected node. The consensus of two views increases the confidence of matching, and removes a blurring phenomenon on the discontinuity of object. This approach has been tested with various types of image such as random dot stereogram and aerial image, and the experimental results show good matching performance.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04a
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• pp.220-222
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• 2000

무선기술의 발전과 다양한 휴대용 장비가 개발되면서 무선 인터넷 서비스에 대한 요구가 증가하고 있다. 하지만 현재 네트워크에서 사용되고 있는 IPv4를 이용해서는 IP의 이동 환경을 지원하지 못한다. 이에 여러 연구가 진행되고 있으며 IETE의 Mobile IP Working Group에서는 기존의 IPv4를 사용하면서도 이동환경을 지원하기 위한 이동 IP에 대해 연구를 진행하고 있다. 이에 본 논문에서는 인터넷에서 계층적이며 효율적인 이동성 지원을 위하여 인트라 도메인과 인터도메인에서 이동성 지원을 위한 기법을 제안한다. 본 논문에서는 멀티캐스트 라우팅 프로콜인 PIM-SM(Protocol Independent Multicase-Sparse Mode)과 MSDP(Multipicast Source Discovery Protocol)를 이용하며, 하나의 이동 노드 (Mobile Node, MN)는 대응 노드(Correspondent Node, CN)에 의해 특정한 멀티캐스트 그룹으로 인식된다. 이동 노드를 목적지로 하는 패킷은 RP(Rendezvous Point)로 보내진 후 이동노드의 현재 위치로 포워딩 된다. 또한 인트라 도메인과 인터 도메인에서 계층적이며 효율적인 방법을 지원함으로써 핸드오프 지연을 감소시키며, 홈 에이전트와 대응 노드에 부가되던 부하를 줄일 수 있다.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.799-802
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• 2000

There are many methods that extract the depth information based on the blurring ratio for object point in DFD(Depth from Defocus). However, it is often difficult to measure the depth of the object in two-dimensional images that was affected by various elements such as edges, textures, and etc. To solve the problem, new DFD method employing the texture classification with a neural network is proposed. This method extracts the feature of texture from an evaluation window in an image and classifies the texture class. Finally, It allocates the correspondent value for the blurring ratio. The experimental result shows that the method gives more accurate than the previous methods.