• Title/Summary/Keyword: L2 트리거

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A Micro Mobility Management Scheme in Wireless LAN Environments (무선 LAN환경에서 마이크로 이동성 지원 방안)

  • 고광신;차우석;김형준;조기환
    • 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.

A Comparative Study of IP Mobility Protocols : Fast Handover vs. Mobile IPv6 (IP 이동성 지원 프로토콜에 대한 비교 연구: Fast Handover 대 Mobile IPv6)

  • 백상헌;최양희
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.6A
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    • pp.651-659
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    • 2004
  • The Fast Handover protocol [1] provides seameless handover in wireless If networks by minimizing handover latency, which uses anticipation based on layer 2 (L2) trigger information. Therefore, it incurs higher signaling costs compared with the basic Mobile U protocol. Furthermore, since the L2 trigger is based on fluctuating wireless channel states, the handover anticipation may sometimes be incorrect. In the case of incorrect anticipation, unnecessary buffer space may be used for the purpose of providing a smooth handover. Therefore, it is essentical to analyze these overhead costs, in order to evaluate and compare the performance of Fast Handover with that of the basic Mobile U protocol. In this paper, we analyzed the overhead associated with Fast Handover including the signaling cost and the packet delivery cost. We formulated these costs based on a timing diagram and compared Fast Handover with basic Mobile Ipv6 in terms of their packet loss rates and buffer requirements. Also, we studied the impact of the L2 triggering time on the total overhead cost.

Implementation and Analysis of the FMIPv6 (Fast Handover for Mobile IPv6) Using Layer 2 Triggers (제2계층 트리거를 이용한 FMIPv6 구현 및 분석)

  • Oh, Seung-Hun;Lee, Sung-Sik;Kim, Young-Han
    • The KIPS Transactions:PartC
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    • v.12C no.4 s.100
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    • pp.551-558
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    • 2005
  • In this paper, we implement the fast handovers for mobile IPv6 (FMIPv6) on Linux system. Due to its dependency on operations in layer-2 (L2), we have added some functions into the network driver to generate triggers as the mobile node moves. We design and implement the FMIPv6 functions divided into two parts as an access router and a mobile node. We compare the packet loss and delay of the FMIPv6 implementation during the handover period with those of the MIPv6 and investigate the performance improvement.

Cross Layer Optimization of Vertical Handover for Heterogeneous Wireless Networks (이기종 무선 네트워크간 핸드오버를 위한 교차계층 최적화 방안)

  • Kim, Hak-Soo;Kim, Wee-Youn;Jo, Jae-Ho;Cho, Jin-Sung
    • Proceedings of the Korean Information Science Society Conference
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    • 2008.06d
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    • pp.126-130
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    • 2008
  • Mobile IP는 단말에게 이동성을 제공해 줌으로써 이동하면서도 인터넷에 접속할 수 있게 해준다. 하지만 L2 연결과 L3 연결이 순차적으로 진행되어 핸드오버시 지연과 데이터 로스의 문제가 발생한다. 이러한 핸드오버 과정에서 발생하는 지연과 데이터 로스를 줄이기 위해 L2 트리거를 이용한 Fast Handover 기술이 개발되었지만 Fast Handover 기술 역시 L2 연결과 L3 연결이 독립적으로 진행된다. 본 논문에서는 Mobile IP의 L3 핸드오버 과정과 이기종 네트워크들의 L2 핸드오버 과정을 통합하고 핸드오버 과정을 최적화하여 성능 개선된 핸드오버 방안을 제안하고 성능평가를 통해 우수함을 보인다.

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Korean Medicine Treatment Accompaning Myofascial Trigger-Point Accupuncture for Lower Urinary Tract Symptoms after Radical Prostatectomy : A Case Report (근치적 전립선 절제술 후 발생한 하부요로증상의 근막 트리거 포인트 침치료를 병행한 한의치료 1례)

  • Lee Jin Kwang
    • The Journal of Korean Medicine
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    • v.45 no.1
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    • pp.240-250
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    • 2024
  • Objectives: The purpose of this study is to report a case of Korean medicine treatment accompaning myofascial trigger-point accupuncture for severe & persistent lower urinary tract symptoms after radical prostatectomy. Materials and Methods: A prostate cancer patient with severe & persistent lower urinary tract symptoms after radical prostatectomy conducted 26 months ago, was treated with Korean medicine accompaning myofascial trigger-point accupuncture. The International Prostate Symptom Score(IPSS), the IPSS Quality of Life(IPSS-QoL) and the Overactive Bladder Symptom Score(OABSS) questionaires were administered to evaluate the effect of treatment for lower urinary tract symptoms. Results: After 5 month treatment with Korean medicine accompaning myofascial trigger-point accupuncture, IPSS, IPSS-QoL and OABSS progressed from 28 to 8, from 5 to 2 and from 12 to 4 respectively. Conclusion: This case study suggests that Korean medicine accompaning myofascial trigger-point accupuncture may contribute to treat severe & persistent lower urinary tract symptoms after radical prostatectomy.

A Study on the Reversible SCR Servo Amplifier (정역전이 가능한 SCR 서보증폭기에 관한 연구)

  • Ahn, B. W.;Park, S. K.
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.31 no.2
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    • pp.190-198
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    • 1995
  • Many industrial servo amplifiers employ power transister as output device. Thyristor converters are not adopted to drive servo motor, although thyristor is superior to power TR in power rating, noise immunity, price, and size. The reason is, thyristor has no ability of self turn - off. Here in this paper line commutation, in which thyristor is turned off naturally since cathode voltage is higher than anode as time goes by, is employed to turn on thyristor with a delicate sequence. We developed thyristor servo amplifier which does not cause any damage on thyristor because it is designed to prevent triggering the two SCRs in the same arm simultaneously. And it was made clearly how to trigger SCR without any power line shorting and also harmonic analysis is carried out with the aid of FFT analyzer and proved that it can be used even severe reactive load. The designed circuit operated as a good DC amplifier in conventinal servomotor and the results can be use as a position control system application.

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An Efficient Network Mobility Handoff Scheme Based on Movement Pattern of a Train (이동예측이 가능한 철도차량의 이동성을 기반으로 한 네트워크 이동성 핸드오프 방안)

  • Lee, Il-Ho;Lee, Jun-Ho
    • Journal of the Korean Society for Railway
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    • v.10 no.6
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    • pp.758-765
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    • 2007
  • In this paper, we propose an efficient seamless handoff scheme to minimize packet loss and unnecessary packets on the Internet using the peculiar mobility characteristics of public vehicles such as trains. MR (Mobile Router) in a train visits each AR (Access Router) in the fixed order. As the MR detects reachability to the NAR (Next Access Router) on the new link, the PAR (Previous Access Router) can directly deliver packets from MR's HA (Home Agent) to the NAR according to the HML (Handoff Mobile router List). Then. the NAR buffers them until the MR finishes L3 (Layer 3) handoff procedure with the NAR. Therefore, our scheme can support a seamless handoff without the packet loss and unnecessary packets on the Internet. The result of our performance evaluation has shown that the proposed scheme could provide excellent performance, compared with the NEMO basic support protocol and the Bi-casting protocol.

An Enhanced Fast Handover Scheme for Real-Time Traffic in IPv6 Based WiBro Network (IPv6기반 와이브로 시스템에서 실시간 트래픽을 위한 개선된 빠른 핸드오버 방안)

  • Jeong, Seok-Jong;Lee, Sung-Kuen;Park, Jin-Woo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.4A
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    • pp.377-386
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    • 2008
  • In this paper, a new handover management scheme has been proposed to reduce handover latency and to support fast handover without packet losses, so that it may be applicable to the wireless mobile Internet system such as IPv6-based WiBro system. To minimize the handover latency in processing of movement detection, we propose the handover management scheme which simplifies the handover message exchanging procedure between mobile subscriber station (MSS) and network by integrating layer 2 and layer 3 handovers efficiently based on the layer2 information. To reduce the processing delay from new care-of-address (NCoA) configuration during handover, we propose that NCoA is created, distributed and managed by new access control router (NACR). In addition, in order to minimize the packet transmission delay and eliminate the packet losses, the proposed scheme employs a crossover router (CR) which is upper network located over PACR and NACR and employs the packet buffering for MSS. The simulation study shows that the proposed scheme achieves loss-free packet delivery and low latency in the environment of narrow overlapped cell area or high velocity of the MSS, comparing the performance with the conventional schemes.

A Mechanism for Seamless Mobility Service with the Network-based Preemptive Operations (네트워크 기반의 Preemptive 동작을 통한 끊김없는 서비스 제공 메커니즘)

  • Min, Byung-Ung;Chung, Hee-Chang;Kim, Dong-Il
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2007.10a
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    • pp.54-57
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    • 2007
  • Much researches have studied for seamless mobility service. Those focused on minimizing the delay time due to the handover. In this paper, we suggest seamless mobility service with the network-based preemptive operations. With these operations, if it's found that the MT(Mobile Terminal)'s handover using L2-trigger event, old access network buffers the delivering data. Therefore this can decrease the data drop rates. And also, this can deal with the ping-pong's phenomenon of MT. At the end of MT's movement, these operations can provide seamless mobility service sending buffered data after checking the MT's movement. This mechanism uses MPLS-LSP(MultiProtocol Label Switching-Label Switched Path) in core network for fast process.

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Estimation of Internal Motion for Quantitative Improvement of Lung Tumor in Small Animal (소동물 폐종양의 정량적 개선을 위한 내부 움직임 평가)

  • Yu, Jung-Woo;Woo, Sang-Keun;Lee, Yong-Jin;Kim, Kyeong-Min;Kim, Jin-Su;Lee, Kyo-Chul;Park, Sang-Jun;Yu, Ran-Ji;Kang, Joo-Hyun;Ji, Young-Hoon;Chung, Yong-Hyun;Kim, Byung-Il;Lim, Sang-Moo
    • Progress in Medical Physics
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    • v.22 no.3
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    • pp.140-147
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    • 2011
  • The purpose of this study was to estimate internal motion using molecular sieve for quantitative improvement of lung tumor and to localize lung tumor in the small animal PET image by evaluated data. Internal motion has been demonstrated in small animal lung region by molecular sieve contained radioactive substance. Molecular sieve for internal lung motion target was contained approximately 37 kBq Cu-64. The small animal PET images were obtained from Siemens Inveon scanner using external trigger system (BioVet). SD-Rat PET images were obtained at 60 min post injection of FDG 37 MBq/0.2 mL via tail vein for 20 min. Each line of response in the list-mode data was converted to sinogram gated frames (2~16 bin) by trigger signal obtained from BioVet. The sinogram data was reconstructed using OSEM 2D with 4 iterations. PET images were evaluated with count, SNR, FWHM from ROI drawn in the target region for quantitative tumor analysis. The size of molecular sieve motion target was $1.59{\times}2.50mm$. The reference motion target FWHM of vertical and horizontal was 2.91 mm and 1.43 mm, respectively. The vertical FWHM of static, 4 bin and 8 bin was 3.90 mm, 3.74 mm, and 3.16 mm, respectively. The horizontal FWHM of static, 4 bin and 8 bin was 2.21 mm, 2.06 mm, and 1.60 mm, respectively. Count of static, 4 bin, 8 bin, 12 bin and 16 bin was 4.10, 4.83, 5.59, 5.38, and 5.31, respectively. The SNR of static, 4 bin, 8 bin, 12 bin and 16 bin was 4.18, 4.05, 4.22, 3.89, and 3.58, respectively. The FWHM were improved in accordance with gate number increase. The count and SNR were not proportionately improve with gate number, but shown the highest value in specific bin number. We measured the optimal gate number what minimize the SNR loss and gain improved count when imaging lung tumor in small animal. The internal motion estimation provide localized tumor image and will be a useful method for organ motion prediction modeling without external motion monitoring system.