• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.316-316
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• 2004

• The Transactions of the Korea Information Processing Society
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• v.7 no.11S
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• pp.3714-3722
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• 2000

The research related to the mobility support in the Internet can he classified into two fields. One is Macro mobility and the other is Micro mobility In case of \lacro Mobility, the standard, RFC 2002 by IETF is getting focused. But for Micro mobility, a variety of strategies have been discussed. In this paper. we introduce the concept of an LA and propose the strategy that makes it possible for the LA to fully concern frequent local handoff without using the HA. Therefore we can limit the longest handoH delay to a certain degree regardless of the distance between the MN and the HA of the MN. For the registration cost and the packet drop probability due to the registration delay, we prove the performance enhancement of the existing Mobile IP in case that we apply the concept of the LA to existing Mobile IP.

• The KIPS Transactions:PartC
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• v.11C no.2
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• pp.193-202
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• 2004

Handoff if the most Important feature for the user's mobility in a cellular communication system, which is related to resource reservation at nearby cells. For efficient resource reservation, mobility prediction has been reported as an effective means to decrease call dropping probability and to shorten handoff latency in wireless cellular environments. Several early proposed handoff schemes making use of tile user's movement history on a cell-by-cell basis work on the assumption that the user's movements are restricted to the indoor locations such as an office or a building. However, those algorithms cannot be applied to a micro-cell structure or a metropolis with complicated structure of roads. In this paper, to overcome those drawbacks we propose a new mobility prediction algorithm, which stores and uses the history of the user's positions within the current cell to predict the next cell.

• Journal of KIISE:Information Networking
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• v.29 no.2
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• pp.197-203
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• 2002

This paper proposes a new agent based mechanism called a Multicast Handoff Agent (MHA) to reduce handoff latency for IP multicast. The MHA acts as a proxy for an Internet Group Management Protocol (IGMP) of Mobile Nodes (MNs) at each Base Station (BS) and keeps information for members of multicast groups in a cell. When an MN moves to a next cell, the MHA immediately sends unsolicited reports without waiting for the IGMP query. The mechanism was evaluated through simulation and analysis and compared with the IGMPv2 for micro-mobility and the IGMP traffic. Simulation results show that handoff latency for micro-mobility can be largely reduced and the IGMP control traffic on the wireless links during the duration of membership can be eliminated. Thus, this mechanism is superior to the existing mechanism in both micro-mobility and battery duration, as the need not to reply to a query conserves battery power.

• Journal of Information Technology Services
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• v.20 no.6
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• pp.83-95
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• 2021

In this study, various usage patterns were analyzed after establishing a data mart for micro mobility analysis based on the rental history of public bicycles in Seoul. Rental history data is origin-destination data that includes the rental location and time, and the return location and time. About 1500 rental locations were classified according to the characteristics of the location to create a 'station type' dimension. We also created a 'path type' dimension that displays whether the rental location and return location are the same. In addition, a derived variable called speed, which is obtained by dividing the distance used by the time used, is added, and through this, the characteristics of the riding area and the reason for the rental can be estimated. Meanwhile, administrative district link, administrative neighborhood link, and station type link were created to apply network analysis. Through this analysis, the roles and proportions of administrative districts, public facilities, and private facilities engaged in micro-mobility services were visualized. 49.9% of rentals occur at rental offices near transportation facilities, and half of them occur at rental offices near subway stations. The number of rentals during the evening rush hour is more than double that of the morning rush hour. When the path type is unidirectional, there is a fixed destination, so the distance and time used are short, and the movement speed tends to be high. In the case of round-trip, the purpose of use is exercise or leisure, so the distance and time used are long, and the movement speed is slow. It is expected that the results of the analysis can be used as reference materials for selecting new rental locations, providing convenient services for users, and developing user-specialized products.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.782-784
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• 2002

Many compound semiconductors which have high carrier mobility and small band gap have attentive in application of various practical a field. Especially, InSb served for Hall device and magnetic resistor such as magnetic sensor because InSb thin film has high mobility. Many studies on InSb thin film deposition because In and Sb has been very different feature of vapor pressure($10^4$ times) When In and Sb deposited. In this paper studied it In and Sb deposited simultaneously using by method of co-sputtering deposotion. This process, get to effects of manufacture process simplification. After that this paper observed micro structure and electronic behavior of InSb thin film using by co-sputtering.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.736-738
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• 2003

Hierarchical Mobile IP(HMW)는 Micro Mobility 관리를 위한 효율적인 방안을 제공한다. 즉, HMIP 환경에서는 Mobility Anchor Point(MAP) 관리 도메인내의 이동시 MN의 지역 바인딩 갱신(Local Binding Update) 메시지를 MAP에서 처리함으로써, 홈 도메인과의 등록 메시지 교환량을 감소시킬 수 있다. 그러나 MAP 관리 도메인과 MN 사이에는 기 설정된 비밀 정보가 존재하지 않기 때문에, 사용자 이동시 필요한 인증을 수행하기 위해서는 MN과 홈 도메인과의 정보 교환이 요구된다. 본 논문에서는 HMIP 환경에서 사용자의 인증을 위해 Diameter Mobile TPv6 응용을 적용한 모델을 제시한다. 이와 함께, MAP와 연계된 방문망의 AAA 서버로의 인증 권한 위임을 통해, 홈 도메인과의 정보 교환을 감소시키는 효율적인 Micro Mobility 관리 방안을 제공한다.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.209-210
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• 2006

Hierachical Mobile IPv6 (HMIPv6) solves Micro-mobility protocol problem about Handover. Mobility Anchor Point(MAP) helps reducing the handover, but this makes a load on the MAP. Besides the MAP operates this work everytime, and every Nodes. In this paper, we propose the algorithm that reduces the amount of Map working.

• Journal of KIISE:Information Networking
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• v.31 no.2
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• pp.158-170
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• 2004

Mobile IP is a base protocol to support host mobility in IP-based wireless network. It is well known that the protocol contains two main delay factors on a handoff process; one is to detect a host movement, and the other is to register the host's current location to its home network. This paper examines Layer 2(L2) handoff procedure in the IEEE 802.11 Wireless LAN, and identifies these L2 triggers that can be usefully applied to Layer 3(L3) handoff. Then, the MCAA(Multiple-Casting using Anchor Agent) mechanism is proposed. It makes use of the L2 trigger and the network topology to construct an anchor agent dynamically, and the multiple-casting scheme to prevent an ongoing packet to be lost. Using a network simulator, the proposed mechanism has been evaluated the handoff delay and the packet lost point of view, in comparison with the regional registration protocol which is the most well known micro mobility support mechanism.

• Korea Information Processing Society Review
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• v.8 no.4
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• pp.82-86
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• 2001