• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.