• 제목/요약/키워드: multichannel switching

검색결과 16건 처리시간 0.021초

다채널 미세전극칩 임피던스 분석을 위한 자동 스위칭 시스템: 한계점 및 개선 방안 (Automatic Switching System for The Impedance Analysis of Multichannel icroelectrode Arrays: Limits and Improvement Scheme)

  • 이석영;남윤기
    • 대한의용생체공학회:의공학회지
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    • 제32권3호
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    • pp.207-217
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    • 2011
  • Electrode impedances are measured to quantitatively characterize the electrode-electrolyte or cell-electrode interfaces. In the case of high-density microelectrode arrays(MEAs) that have been developed for brainmachine interface applications, the characterization process becomes a repeating and time-consuming task; a system that can perform the measurement and analysis in an automated fashion with accuracy and speed is required. However, due to the large number of channels, parasitic capacitance and off-capacitance components of the switching system become the major factors that decreased the accuracy for the measurement of high impedance microelectrodes. Here we investigated the implementation of automatic impedance measurement system with analyzing the causes of possible measurement-related problems in multichannel switching configuration. Based on our multi-channel measurement circuit model, we suggest solutions to the problems and introduce a novel impedance measurement scheme using electro-mechanical relays. The implemented measurement system could measure |Z| < 700 $k{\Omega}$ of impedance in - 10% errors, which can be widely applicable to high density neural recording MEAs.

An Energy Efficient Multichannel MAC Protocol for QoS Provisioning in MANETs

  • Kamruzzaman, S.M.;Hamid, Md. Abdul
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제5권4호
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    • pp.684-702
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    • 2011
  • This paper proposes a TDMA-based multichannel medium access control (MAC) protocol for QoS provisioning in mobile ad hoc networks (MANETs) that enables nodes to transmit their packets in distributed channels. The IEEE 802.11 standard supports multichannel operation at the physical (PHY) layer but its MAC protocol is designed only for a single channel. The single channel MAC protocol does not work well in multichannel environment because of the multichannel hidden terminal problem. Our proposed protocol enables nodes to utilize multiple channels by switching channels dynamically, thus increasing network throughput. Although each node of this protocol is equipped with only a single transceiver but it solves the multichannel hidden terminal problem using temporal synchronization. The proposed energy efficient multichannel MAC (EM-MAC) protocol takes the advantage of both multiple channels and TDMA, and achieves aggressive power savings by allowing nodes that are not involved in communications to go into power saving "sleep mode". We consider the problem of providing QoS guarantee to nodes as well as to maintain the most efficient use of scarce bandwidth resources. Our scheme improves network throughput and lifetime significantly, especially when the network is highly congested. The simulation results show that our proposed scheme successfully exploits multiple channels and significantly improves network performance by providing QoS guarantee in MANETs.

다중 채널 ATM 스위치에서의 장애 관리 (Fault Management in Multichannel ATM Switches)

  • 오민석
    • 한국통신학회논문지
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    • 제28권8A호
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    • pp.569-580
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    • 2003
  • 다중 채널 스위치 구조의 중요한 이점 중의 하나는 스위치 내부의 장애에 대한 내성 (tolerance)을 스위치 구조에 결합시킬 수 있다는 것이다. 예를 들어 하나의 다중 채널 그룹에 속하는 경로에 장애가 있을 경우, 장애 경로로 통과했어야 하는 트래픽을 나머지 경로가 책임 질 수 있다. 또한 스위치 소자에 발생하는 장애는 ATM 셀(cell)의 잘못된 라우팅을 야기하거나 순서를 뒤바꾸게 할 수 있다. 본 논문에서는 다중 채널 크로스바(crossbar) ATM 스위치에서의 장애 위치 알고리즘을 제안하였다. 최적의 알고리즘은 시간적으로 최상의 성능을 보여주지만, 계산상으로는 복잡하여 결과적으로 실제 구현을 어렵게 만든다. 이러한 단점을 극복하기 위해 최적의 알고리즘보다 계산상으로 효율적인 온라인 알고리즘을 제안하였다. 성능은 시뮬레이션을 통해 검증하였으며 그 결과로서 온라인 알고리즘의 성능은 랜덤 (random) 트래픽 및 버스트한 (bursty) 트래픽에 대해 거의 최적에 가까운 성능을 보여 준다. 끝으로 장애 위치 확인 알고리즘에 의해 제공되는 정보를 이용한 장애 복구 알고리즘을 제안하였다.

결합인덕터와 직렬 공진을 이용한 비절연 다중 LED 전류 평형 기법 (Nonisolated Multichannel LED Current Balancing Scheme Using Coupled Inductor and Series Resonant Converter)

  • 신유용;홍다헌;최병조;차헌녕
    • 전력전자학회논문지
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    • 제26권4호
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    • pp.249-255
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    • 2021
  • A novel current balancing technique for multichannel light-emitting diode (LED) that uses a series resonance and coupled inductor is proposed in this paper. The proposed LED driver balances output currents through frequency control and enables zero-voltage switching. The proposed converter utilizes the charge balance condition of the resonant capacitor and the current sharing function of the coupled inductor to achieve whole LED current balancing without an additional controller. The proposed coupled inductor can integrate the current balancing function and the resonant inductor, so the power density can be increased by reducing the number of magnetic devices. A 40 W prototype is built to verify the validity of this LED driver, and the experimental results are successfully obtained.

크로스바 ATM 스위치에서의 장애 관리 (Fault Management in Crossbar ATM Switches)

  • 오민석
    • 정보처리학회논문지C
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    • 제12C권1호
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    • pp.83-96
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    • 2005
  • 다중채널 스위치는 ATM (Asynchronous Transfer Mode)로 널리 사용되는 스위치 구조이며, 스위치의 내부에 장애에 대한 내성(tolerance) 을 구현할 수 있는 것으로 알려져 있다. 예를 들어, 하나의 다중 채널 그룹에 속하는 링크에 장애가 있을 경우, 장애 링크로 통과하려는 트래픽을 여분의 링크가 책임을 질 수 있게 할 수 있다. 스위치 소자에 발생하는 장애는 ATM 셀을 잘못 라우팅하거나 출력단에 도달하는 셀의 순서를 뒤바꾸게 할 수 있다. 본 논문에서는 다중 채널 크로스바 ATM 스위치에 적용할 수 있는 두 가지의 장애 위치 확인 알고리즘을 제안한다. 첫 번째로 제안하는 최적 알고리즘은 시간적으로 최상의 성능을 보여주지만, 계산상으로는 복잡하게 되어 결과적으로 실제 구현이 어려울 수 있다. 이러한 문제점을 해결하기 위해 최적의 알고리즘보다는 계산상으로 보다 효율적인 온라인 알고리즘을 제안한다. 두 알고리즘의 성능은 시뮬레이션을 통해 검증한다. 온라인 알고리즘은 랜덤 트래픽 및 버스티(bursty) 트래픽에 대해 거의 최적에 가까운 성능을 보여 준다. 한편, 제안된 알고리즘으로 장애론 찾아낼 수 없는 경우가 있는데, 그에 대한 열거 및 원인을 제시한다. 끝으로 장애 위치 확인 알고리즘을 이용해서 찾은 장애를 우회하기 위해 행과 연을 추가하는 장애 복구 알고리즘을 제안하다.

HPA MMIC to W/G Antenna Transition Loss Analysis and Development Results of W-band Transmitter Module

  • Kim, Wansik;Jung, Juyong;Lee, Juyoung;Kim, Jongpil
    • International Journal of Advanced Culture Technology
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    • 제7권4호
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    • pp.236-241
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    • 2019
  • This paper will read about a multichannel frequency-modulated continuous wave (FMCW) radar sensor with switching transmit (TX) antennas is developed at W-band. To achieve a high angular resolution, a uniform linear array consisting of 5 switching-TX and 12 receive (RX) antennas is employed with the digital beamforming technique. The overall radar front-end module comprises a W-band transceiver and TX/RX antennas. A multichannel transceiver module consists of 5 up-conversion and 12 down-conversion channels, where one of the TX channels is sequentially switched ON. For developing transmitter, we developed an HPA (high power amplified) MMIC chip for W-band radar system and fabricated a transmitter module using this chip. In order to develop the W-band transmitter, we analyzed the important antenna transition structure from HPA MMIC line to W/G (Waveguide)antenna via M/S(microstrip) and fabricated it with 5 transmission channels. As a result, the output power of the transmitter was within 1 dB of the error range after analysis and measurement under normal temperature and environmental conditions.

Novel Single-inductor Multistring-independent Dimming LED Driver with Switched-capacitor Control Technique

  • Liang, Guozhuang;Tian, Hanlei
    • Journal of Power Electronics
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    • 제19권1호
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    • pp.1-10
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    • 2019
  • Current imbalance is the main factor affecting the lifespan of light-emitting diode (LED) lighting systems and is generally solved by active or passive approaches. Given many new lighting applications, independent control is particularly important in achieving different levels of luminance. Existing passive and active approaches have their own limitations in current sharing and independent control, which bring new challenges to the design of LED drivers. In this work, a multichannel resonant converter based on switched-capacitor control (SCC) is proposed for solving this challenge. In the resonant network of the upper and lower half-bridges, SCC is used instead of fixed capacitance. Then, the individual current of the LED array is obtained through regulation of the effective capacitance of the SCC under a fixed switching frequency. In this manner, the complexity of the control unit of the circuit and the precision of the multichannel outputs are further improved. Finally, the superior performance of the proposed LED driver is verified by simulations and a 4-channel experimental prototype with a rated output power of 20 W.

백화점 패션 소비자의 만족과 몰입이 관계전환의도 및 멀티채널 이용의도에 미치는 영향 (The Effects of Department Store Customers' Satisfaction and Commitment on Relationship Switching Intention and Multi-channel Use Intention)

  • 김도연;추호정
    • 한국의류산업학회지
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    • 제15권5호
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    • pp.753-762
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    • 2013
  • This study identifies meaningful factors that influence relationship switching intention and multi-channel use intention for department store customers. Two types of commitment (affective and calculative commitment) are proposed as mediators between satisfaction and behavioral intention. A web-based survey collected fashion product data from consumers who had a relationship with a department store. A total of 150 responses were analyzed by frequency analysis and reliability analysis, CFA, and SEM analysis with SPSS 18.0 and AMOS 18.0. Department store attributes were composed of four factors (product, salespersons, facilities and place, and price and promotion). Department store satisfaction was specified as a second order latent construct which was reflected in the satisfaction with the four department store attributes. Department store satisfaction had a significant negative influence on calculative commitment and a positive effect on affective commitment. Calculative commitment affected switching intention and affective commitment determined multichannel use intention. This study has implications for retail marketers that target fashion consumers and academics who research consumer behavior in retail settings. The most important result is that the affective commitment and the calculative commitment serve different functions. Department store managers need to make an increased effort to instigate an affective customer commitment in order to reduce switching intention.

DSP 칩을 이용한 다중채널 R2MFC/DTMF/CCT 겸용 수신기 (A Single-Chip, Multichannel Combined R2MFC/DTMF/CCT Receiver Using Digital Signal Processor)

  • 김덕환;이형호;김대영
    • 전자공학회논문지B
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    • 제31B권10호
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    • pp.21-31
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    • 1994
  • This paper describes the multichannel combined R2MFC/DTMF/CCT reciver which provides a signaling service functions for call processing control in digital switching system. Using the TMS320C25 DSP chip, we have implemented multi-function receriver shich processes 8 channels of R2MFC, DTMF, and CCT signals simultaneously. In order to increase the channel multiplicity of the combined receiver. R2MFC and CCT receiver were employed by discrete Fourier transform(DFT) method using Goertzel algorithm, and DTMFreceiver was employ by infinite impulse reponse(IIR) filtering method using 4KHz subsampling technique. The combined receiver has 4 function modes for each channel such as R2MFC, DTMF, CCT, and Idle modes. The function mode of each channel may be selected at any time by single-chip micro-controller(.mu.C). Hence, the number of channels assigned for each function mode can be adjusted dynamically according to the signaling traffic variations. From the experimental test results using the test-bed, it has been proved that the combined receiver statisfies all receiver satisfies all receiver specifications, and provides good channel multiplicity and performance, Therefore, it may give a great improvement than existing receiver in cost, reliability, availability, and serviceability.

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위상 배열레이더의 다채널 수신 데이터 전송 기법 (A Transmission Technique of Multichannel Receiver Data for the Phased-Array Radar)

  • 정명득;김한생
    • 한국전자파학회논문지
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    • 제23권10호
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    • pp.1188-1195
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    • 2012
  • 향후 레이더는 능동 위상 배열레이더(Active Phased-Array Radar System)로 발전하는 추세이다. 특히, 다채널 수신 시스템에서 실시간 신호처리를 위해서 신호처리용 보드의 처리 속도와 개수와의 trade-off는 최적화 되어야 한다. 본 논문에서는 많은 양의 수신 데이터를 안테나부에서 신호처리부로 전달하기 위한 전송 기법에 대하여 소개하고자 한다. 그 결과, 기존 방법에 비해 신호처리부의 S/L 보드 개수는 절반(1/2) 수준으로 감소하였고, 통신 전송 속도 여유 마진은 약 2배 더 증가되는 효과가 있다.