• Title/Summary/Keyword: mRelay

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Electrostatic Suspension System of Silicon Wafer using Relay Feedback Control (릴레이 제어법을 이용한 실리콘 웨이퍼의 정전부상에 관한 연구)

  • 전종업;이상욱;정일진;박규열
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.969-974
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    • 2003
  • A simple and cost-effective method for the electrostatic suspension of thin plates like silicon wafers is proposed which is based on a switched voltage control scheme. It operates according to a relay feedback control and deploys only a single high-voltage power supply that can deliver a dc voltage of positive and/or negative polarity. This method possesses the unique feature that no high-voltage amplifiers are needed which leads to a remarkable system simplification relative to conventional methods. It is shown that despite the inherent limit cycle property of the relay feedback based control, an excellent performance in vibration suppression is attained due to the presence of a relatively large squeeze film damping origination from the air between the electrodes and levitated object. Using this scheme, a 4-inch silicon wafer was levitated stably with airgap variation decreasing down to 1 $\mu\textrm{m}$ at an airgap of 100 $\mu\textrm{m}$

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Security performance analysis of SIMO relay systems over Composite Fading Channels

  • Sun, Jiangfeng;Bie, Hongxia;Li, Xingwang
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.14 no.6
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    • pp.2649-2669
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    • 2020
  • In this paper, we analyze the secrecy performance of single-input multiple-output (SIMO) relay systems over κ-μ shadowed fading channels. Based on considering relay model employing decode-and-forward (DF) protocol, two security evaluation metrics, namely, secure outage probability (SOP) and probability of strictly positive secrecy capacity (SPSC) are studied, for which closed-form analytical expressions are derived. In addition, Monte Carlo results prove the validity of the theoretical derivation. The simulation results confirm that the factors that enhance the security include large ratio of (μD, μE), (mD, mE), (LD, LE) and small ratio of (kD, kE) under the high signal-to-noise ratio regime.

Electrostatic Suspension System of Silicon Wafer using Relay Feedback Control (릴레이 제어법을 이용한 실리콘 웨이퍼의 정전부상에 관한 연구)

  • Lee, Sang-Uk;Jeon, Jong-Up
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.10 s.175
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    • pp.56-64
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    • 2005
  • A simple and cost-effective method for the electrostatic suspension of thin plates like silicon wafers is proposed which is based on a switched voltage control scheme. It operates according to a relay feedback control and deploys only a single high-voltage power supply that can deliver a DC voltage of positive and/or negative polarity. This method possesses the unique feature that no high-voltage amplifiers are needed which leads to a remarkable system simplification relative to conventional methods. It is shown that despite the inherent limit cycle property of the relay feedback based control, an excellent performance in vibration suppression is attained due to the presence of a relatively large squeeze film damping origination from the air between the electrodes and levitated object. Using this scheme, a 4-inch silicon wafer was levitated stably with airgap variation decreasing down to $1 {\mu}m$ at an airgap of $100{\mu}m$.

Electrostatic Suspension System of Glass Panels using Relay Feedback Control (릴레이 제어법을 이용한 유리패널의 정전부상에 관한 연구)

  • Jeon, Jong-Up
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.6
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    • pp.71-79
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    • 2008
  • In the manufacture of flat panel display devices, there is a strong demand for contactless glass panel handling devices that can manipulate a glass panel without contaminating or damaging it. To fulfill this requirement, an electrostatic suspension device far glass panels where the glass panel is supported by electrostatic forces without any mechanical contact is proposed. To implement the system with low cost and compactness, switched-voltage control scheme that is based on the relay feedback control is utilized. Relay feedback control method deploys only a single high-voltage power supply that can deliver a DC voltage of positive and/or negative polarity and thus high voltage amplifiers that are costly and bulky are not needed any more. It is shown that despite the inherent limit cycle property of the relay feedback based control, an excellent performance in vibration suppression is attained due to the presence of a relatively large squeeze film damping originating from the electrodes and levitated object. Using this scheme, a $100{\times}100mm^2$ glass panel was levitated stably with airgap variation decreasing down to $1\;{\mu}m$ at an airgap of $100\;{\mu}m$.

SER Analysis of Multi-Way Relay Networks with M-QAM Modulation in the Presence of Imperfect Channel Estimation

  • Islam, Shama N.;Durrani, Salman;Sadeghi, Parastoo
    • Journal of Communications and Networks
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    • v.18 no.5
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    • pp.677-687
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    • 2016
  • Multi-way relay networks (MWRNs) allow multiple users to exchange information with each other through a single relay terminal. MWRNs are often incorporated with capacity achieving lattice codes to enable the benefits of high-rate signal constellations to be extracted. In this paper, we analytically characterize the symbol error rate (SER) performance of a functional decode and forward (FDF) MWRN in the presence of channel estimation errors. Considering M-ary quadrature amplitude modulation (QAM) with square constellations as an important special case of lattice codes, we obtain asymptotic expressions for the average SER for a user in FDF MWRN. The accuracy of the analysis at high signal-to-noise ratio is validated by comparison with the simulation results. The analysis shows that when a user decodes other users with better channel conditions than itself, the decoding user experiences better error performance. The analytical results allow system designers to accurately assess the non-trivial impact of channel estimation errors and the users' channel conditions on the SER performance of a FDF MWRN with M-QAM modulation.

Coverage Extension of the Highway Dedicated Short Range Communication System based on a Fixed Relay

  • Choi, Kwang-Joo;Kim, Hak-Jae;Park, Sang-Kyu
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.8 no.1
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    • pp.30-36
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    • 2009
  • Dedicated Short Range Communication (DSRC) systems in urban areas are used to collect traffic information from vehicles and to provide vehicles with information received from Roadside Equipment (RSE) having a range of 100 meters (m). However, it is not practical to use RSE with a range of 100 m for express highways. In this paper, we expand the standard cell coverage of RSE to 300 m, and adopt fixed relays to cover sites that cannot communicate with the RSE. We demonstrate that the system using the fixed relays is more economical than using only RSE.

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Investigation into Transformer Protective Relay Setting Rule Considering Error Ratio (오차를 고려한 765kV 변압기 보호 계전 정정룰 고찰)

  • Bae, Y.J.;Lee, S.J.;Choi, M.S.;Kang, S.H.;Kim, S.T.;Choi, J.L.;Jeong, C.H.;Yoo, Y.S.;Cho, B.S.
    • Proceedings of the KIEE Conference
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    • 2002.07a
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    • pp.229-231
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    • 2002
  • The digital current differential relaying scheme is widely used for primary protection of 765(kV) power transformer. The current differential relay pickup the internal fault at the threshold which is set at 30% of rating current. Margin of 30% include current transformer error 5%, relay error 5%, on load tap changer error 7% and margin factor 140% obtained from the field experience. In this paper transformer protection relay and relay setting rule of high voltage power system are discussed. And we verify the correctness of relay setting rule with current differential relay using Matlab simulation.

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Performance Analysis of Dual-Hop MBST-ADF Relay Networks Over Quasi-Static Rayleigh Fading Channels

  • Kim, Min-Chan;Lim, Sungmook;Ko, Kyunbyoung
    • International Journal of Contents
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    • v.14 no.1
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    • pp.18-27
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    • 2018
  • The objective of this study was to derive approximate closed-form error rates for M-ary burst symbol transmission (MBST) of dual-hop adaptive decode-and-forward (ADF) cooperative relay systems over quasi-static Rayleigh fading channels. Within a burst, there are pilot symbols and data symbols. Pilot symbols are used for channel estimation schemes and each relay node's transmission mode selection schemes. At first, our focus was on ADF relay systems' error-events at relay nodes. Each event's occurrence probability and probability density function (PDF) were then derived. With error-event based approach, we derived a tractable form of PDF for combined signal-to-noise ratio (SNR). Averaged error rates were then derived as approximate expressions for arbitrary link SNR with different modulation orders and numbers of relays. Its accuracy was verified by comparison with simulation results.

A Development of Diagnosis Expert System for Power System Protective Relay Settings (보호계전기 정정값 진단 전문가 시스템 개발)

  • Kim, K.J.;Lee, S.J.;Choi, M.S.;Kang, S.H.;Kim, H.P.;Lee, W.H.;Choi, H.S.
    • Proceedings of the KIEE Conference
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    • 1999.07c
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    • pp.1394-1396
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    • 1999
  • It is important the protective relay should have high selectivity and sensitivity performance and it is achieved by correct setting of the relay parametes. The verification of accurate setting for the protective relay is very difficult before a actual fault occurs. This paper reports a diagnosis expert system to verify the correctness of the relay setting by using the operation results in the power system fault simulation.

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A Development of Protective Relay Operating-Diagnosis System for Power System (송전계통 선로보호 계전기 동작 진단 시스템)

  • Kim, K.J.;Lee, S.J.;Choi, M.S.;Kang, S.H.;Kim, H.P.;Lee, W.H.;Choi, H.S.
    • Proceedings of the KIEE Conference
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    • 1999.11b
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    • pp.107-109
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    • 1999
  • In the point of view protective relay, the selectivity and sensitivity is very important in its performance. The correct setting of the relay parameter is required. The verification of accurate setting for the protective relay is very difficult before a actual fault occurs. In this paper, we proposed the diagnosis expert system as a method to verify the correctness of the relay setting. The developed system proved effectiveness through the tests on the real systems.

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