• Annual Conference of KIPS
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• 2013.05a
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• pp.446-449
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• 2013

PMIPv6(Proxy Mobile IPv6)는 네트워크 기반 이동성 지원프로토콜로 MN(Mobile Node)에 이동성을 제공하기 위해 제안되었다. PMIPv6는 기존 호스트 기반 이동성 지원 프로토콜에 비해 MN이 핸드오버 시그널링에 참여하지 않기 때문에 무선구간에서의 자원 사용량 감소, MN의 에너지 소비량 감소, 그리고 핸드오버 시그널링 비용 감소의 향상된 성능을 보인다. 하지만 PMIPv6에는 핸드오버 시그널링으로 인한 지연 및 패킷손실의 문제점이 있다. MN이 다음에 이동할 위치를 알고 핸드오버를 미리 준비할 수 있다면 빠른 핸드오버를 지원할 수 있다. 본 논문에서는 MN의 이동경로를 저장하여 이동히스토리를 구성하고 MN이 다음에 이동할 위치를 예측함으로써 빠른 핸드오버를 지원한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.5B
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• pp.437-442
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• 2011

As an Internet Engineering Task Force (IETF) Working Group, 6LoWPAN is standardizing the IPv6 packet transfer technology in accordance with IEEE 802.15.4. It has completed two Request for Comments (RFC) documents, one of which, RFC 4944, addresses fragmentation, reassembly, and header compression technologies. In this paper, a communication mechanism is proposed to provide efficient communication between 6LoWPAN and external nodes. In this mechanism, the gateway between 6LoWPAN and external networks serves as the proxy gateway between nodes. The simulation was conducted using QualNet to compare the performance of the proposed mechanism and the existing RFC 4944 method. The comparative analysis of the proposed mechanism and the existing method showed that the proposed method performed better.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.8
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• pp.674-680
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• 2014

In this paper, as one of the fusion of IT and ocean technology, we propose a scheme to support NEMO in a harbor area network to provide network mobility for passengers, distribution as well as give a connection to an MN from an outside network. In a harbor area under PMIPv6 with NEMO support, a problem could be occurred due to overlapping HA/LMA tunnels and duplicate BCE fields. To Solve these problems, we consider the existing mobility option and add an optional field in the PBU message, which can notify the LMA and HA for either an initial connection or handover request. This procedure can reduce some overlapped steps of binding procedure. Hence, our proposed scheme could reduce an amount of delay and save the processing resource in the harbor area under PMIPv6 with NEMO support.

• 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.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.10
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• pp.119-126
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• 2007

Recently, the mobility of users and mobile communication technologies have developed rapidly. The users in this state also want to connect their devices and to receive services anywhere, anytime. Hierarchical Mobile IPv6 (HMIPv6) has been proposed by the Internet Engineering Task Force (IETF) to compensate for such problems as handover latency and signaling overhead when employing Mobile IPv6 (MIPv6). HMIPv6 supports micro-mobility within a domain and introduces a new entity, namely Mobility Anchor Point (MAP) as a local home agent. However, HMIPv6 has been found to cause longer handover latency when the inter-domain handover occurs. This is because a Mobile Node (MN) has to generate two addresses and register them to Home Agent (HA) a MAP, respectively. In order to solve such problems, we propose a scheme that an MN generates one address and registers it to HA for supporting fast handover during the inter-domain handover process. In the proposed scheme, the load of MAP and MAP domain is reduced because the number of MNs which are managed by MAP is decreased and the MAP does not perform proxy Neighbor Discovery Protocol (NDP) to intercept packets destined to MNs. We evaluate the performance of proposed scheme in comparison to HMIPv6 through the simulation and numerical analysis.

• Journal of the Korea Society of Computer and Information
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• v.12 no.4
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• pp.95-102
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• 2007

Recently, a lot of researchers focus on the sensor middleware that hide the complexity of application developments and provide the abstraction of functions to upper application layer. Although there we several factors to design sensor middleware, the attribute-based naming is considered to be an essential factor among them. However, most existing researches were not designed to reflect the characteristics of sensor networks and have the limitation of attribute-based query extension. This study adopts the concept of Virtual Counterpart to suggest the structure there attribute-based naming is supported by virtual sensor nodes of the middleware on the sink node. Unlike traditional data-centric middleware in which individual sensor nodes process attribute-based query, virtual sensor nodes mapped to physical sensor nodes are running on the middleware of the sink node and process attribute-based query as a proxy of the physical sensor. This approach enables attribute-based naming independent of physical infrastructure and easy extensibility.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.10B
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• pp.630-637
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• 2007

In this paper, we propose an effective handoff mechanism using events at the layer 2 and a tunnel-based mechanism that is performed by sharing information of a mobile node and anticipated-based handoff. Also, we propose a novel anticipated-reservation mechanism using the events triggered at layer 2 to make easy a resource reservation procedure. Comparing with the existing mobile IPv6 handoff mechanism, our proposed handoff mechanism can reduce an amount of handoff latency and traffic volume between access routers where handoff is performed. In the anticipated-reservation mechanism, the amount of signaling traffics between an mobile node and the correspondent nodes can be reduced and then the allocation of resource can be accomplished. We present the performance of our proposed handoff mechanism in the wireless network environment by ns-2 simulation. Although the anticipated-reservation mechanism including a proxy agent is explained without performance evaluation, we can validate the operation of our proposed model only by the procedure of message flow.

• Journal of Digital Contents Society
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• v.12 no.1
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• pp.11-21
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• 2011

The PMIPv6 protocol that has been recently presented as an alternative for the MIPV6 has been getting much persuasion by the system resource and the network bandwidth and the advancement of the network cost. we propose an effective scheduling for multicast services based on the PMIPv6 with hand-over mechanism. it provides an additional function that is able to change multicast join processes dynamically in accordance with MAG status. in order to evaluate the ability of the proposed scheme's We test the performance of hand-over and node join costs with similar techniques. The result of simulation shows improves about 13~35% of performance.

• Journal of Information Science Theory and Practice
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• v.2 no.2
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• pp.6-15
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• 2014

Initial based disambiguation of author names is a common data pre-processing step in bibliometrics. It is widely accepted that this procedure can introduce errors into network data and any subsequent analytical results. What is not sufficiently understood is the precise impact of this step on the data and findings. We present an empirical answer to this question by comparing the impact of two commonly used initial based disambiguation methods against a reasonable proxy for ground truth data. We use DBLP, a database covering major journals and conferences in computer science and information science, as a source. We find that initial based disambiguation induces strong distortions in network metrics on the graph and node level: Authors become embedded in ties for which there is no empirical support, thus increasing their sphere of influence and diversity of involvement. Consequently, networks generated with initial-based disambiguation are more coherent and interconnected than the actual underlying networks, and individual authors appear to be more productive and more strongly embedded than they actually are.

• Journal of the Korea Society of Computer and Information
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• v.23 no.9
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• pp.35-42
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• 2018

In this paper, we propose an optimal streaming service method based on Hybrid CDN/P2P architecture. Recently, video streaming utilizes a CDN (Content Delivery Network) operation technique based on a Proxy Server, which is an end node located close to a user. However, since CDN has a fixed network traffic bandwidth and data information exchange among CDNs in the network is not smooth, it is difficult to guarantee traffic congestion and quality of image service. In the hybrid CDN/P2P network, a data selection technique is used to select only the data that is expected to be continuously requested among all the data in order to guarantee the QoS of the user who utilizes the limited bandwidth efficiently. In order to search user requested data, this technique effectively retrieves the storage information of the constituent nodes of CDN and P2P, and stores the new image information and calculates the deletion priority based on the request possibility as needed. Therefore, the streaming service scheme proposed in this paper can effectively improve the quality of the video streaming service on the network.