• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.10
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• pp.61-67
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• 2004

The next generation cellular wireless communication systems require high data rate transmissions and large system capacities. In order to meet these requirements, multiple antennas can be used at the base and mobile stations, forming MIMO(Multiple Input Multiple Output) channels. This paper proposes a MIMO SDMA(Space Division Multiple Access) technique with dynamic slot allocation which allows the transmitter to efficiently transmit parallel data streams to each of multiple receivers. The proposed technique can increase system capacities significantly by transmitting a larger number of data streams than conventional MIMO techniques while minimizing the performance degradation due to the beamforming dimension reduction.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.3
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• pp.123-126
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• 2011

As the number of users of smart phone and smart pad are increasing, the deployment of WiFi APs has been accelerated. Also Internet local broadcasting service will be activated near future. But transmission error is the critical problem, due to the one-way transmission of the data to the receivers. In this paper, FER is analysed according to BER and frame length, and repetitive transmission technique is proposed to reduce the effective FER.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1468-1473
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• 2011

With the proliferation of wireless LAN and smart phones, IP local broadcasting technology has been developed, and the new solution should be studied for error corrupted frames in the wireless broadcasting channel. In push service system using point-to-multi-point connection among broadcasting server and receivers, the technology proposed in this paper provides an effective data broadcasting system by employing frame length adjustment, redundant transmission, and repetitive transmission method.

• Journal of KIISE:Information Networking
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• v.29 no.1
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• pp.48-56
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• 2002

This paper proposes an IP(Internet Protocol) multicast routing method by multiple tree routes. Multiple trees, instead of a single tree, improve the quality of multicast services with nonlinear link cost and huge traffic demand. The proposed method adds tree routes until it satisfies target conditions, and it splits the multicast traffic demand into the chosen tree routes. We develop a mathematical model and optimal conditions for traffic splitting. The method works on the problems with many different simultaneous multicast traffic. Various experiments were carried and the results show that the new multicasting is fairly effective on end-to-end quality of services.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.470-474
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• 2004

오늘날 산업현장에서는 다양한 필드버스 제품들이 사용되고 있으며 여러 필드버스들 사이의 통신에 관한 문제가 이슈화 되고 있다. 본 논문에서는 현재 사용되고 있는 필드버스들 가운데 가장 많이 사용되고 있는 Profibus와 CAN 네트워크를 대상으로 이기종 필드버스 시스템 사이의 실시간 데이터 전송을 위한 PC 기반의 게이트웨이 장치를 구현하고 그 타당성을 복수전동기 구동실험을 통하여 검증해 보였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.11 no.2
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• pp.146-151
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• 1986

The analysis procedure for open-circuited interdigital multiple coupled microstrip-line structures for applications as wideband DC blocks are presented. The exact frequency responses for the transmission coefficient computed by utilizing the quasi-TEM parameters of coupled microstrip lines are shown.

• Journal of Advanced Navigation Technology
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• v.22 no.2
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• pp.148-153
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• 2018

This paper proposes a single-input multiple-output (SIMO) self-resonant wireless power transmission system for transmitting power to multiple receivers and the characteristics are simulated and measured. A 600 mm diameter transmission single loop, a 600 mm diameter helical transmission resonant coil, an external diameter 900 mm planar spiral reception resonant coil, and an $80{\times}60mm^2$ flat plate square coil as a receiver are used to form a wireless power transmission system 600 mm away with the table structure. For optimal characteristics, the wireless power transmission coils are designed by EM simulation and equivalent circuit analysis, and the characteristics are simulated and measured. The variation of the efficiency with distance from the center of the spiral resonant coil is analyzed and the measured efficiency is 57% for one receiver and for the two receivers, the efficiency is 37% for each receiver.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.57-60
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• 2000

본 논문은 전송되는 멀티캐스트 트래픽에 의해 아크별로 발생하는 전송비용의 합을 최소화하는 멀티캐스트 경로 설정 알고리즘을 제시한다. 비용함수는 콘벡스 형태이고 멀티캐스팅이 요구되는 트래픽은 분할 전송이 가능하다고 가정한다. 가정에 의해 분할되는 트래픽은 여러 개의 다른 멀티캐스트 트리경로 상으로 전송이 가능하며 총 전송비용도 줄일 수 있다. 트래픽의 분할전송이 가능하여도 만일 비용함수가 선형이면 이는 Steiner 문제가 된다. 본 연구는 단일 멀티캐스트 트래픽 수요형태만을 고려한 본 연구자들의 수행연구［1］에 대한 계속연구로서 복수개의 멀티캐스트 트래픽 수요형태를 고려한다. 또한 본 연구의 결과에서 얻는 많은 멀티캐스트 트리 경로들 중 전송비용을 최소화하도록 하면서 제한된 k개의 트리 경로들을 선택하는 휴리스틱 방법을 소개한다. 본 연구는 ATM 망의 멀티캐스트 트래픽을 위한 가상경로 설계 또는 인터넷 환경의 다양한 멀티캐스트 트래픽을 위한 경로설정 등에 적용될 수 있다. 임의의 적용 망에 대한 결과를 포함한다.

• The Transactions of the Korea Information Processing Society
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• v.6 no.8
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• pp.2179-2187
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• 1999

To privide multimedia mobile communication services for the users in scattered locations, the application ATM cells efficiently in wireless communications, it is effective to the use TDMA method. However, it is necessary to have methods to compensate the CDV(cell delay variation) caused by the difference between TDMA-ATM and cell stream multiplexing of the users. This paper optimizes the cell control time(Tc) when VBR traffic inputs have MMPP by applying CDV characteristics of time stamp method, which has the most advantages among compensation methods of CDV. This paper suggests a cell stream multiplex method employing time stamp techniques to reduce CDV for wireless suggest method shows that CDV distribution and cell stream multiples rangd can be controlled to 1.2${\times}$Tc which reduced over the VBR service in the TDMA-WATM transmission. This paper also presents evaluation of the suggested architecture obtained simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.8
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• pp.2042-2051
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• 1998

VBR compressed, pre-recorded video is known to exhibit significant, multiple time-scale bit rate variability. To reduce the variability and burstiness of the aggregated transmission rate as low as possible, in this paper, we present an adaptive bandwidth smoothing algorithm, that can be effectively applicalble for VoD services over a shared-medium channel. For these environments where many clients are connected to a single server, by introducing the conventional MVBA(minimum variability bandwidth allocation) algorithm and controlling adaptively the conventional MVBA(minimum variability bandwidth asllocation) algorithm and controlling adaptively the aggregated transmission rate whenever a new clients request is arrived at the server side, the proposed algorithm effectively reduces the burstiness and variability of the aggregated transmission rate. Through computer experiments, it is shown that the proposed method perporms better than the convertional non-aggregated bandwidth smoothing schemes in terms of the peak rate, standard deviation, number of rate changes for the aggregated traffic.