• Title/Summary/Keyword: pi

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Minimum Data Response Time of HiPi-Bus (HiPi-Bus의 최소 데이터 응답시간)

  • Gi, An-Do;Park, Byung-Kwan;Yoonm Yong-Ho
    • ETRI Journal
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    • v.13 no.2
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    • pp.28-33
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    • 1991
  • HiPi-Bus 는 여러가지 전송형태를 지원하며 이들은 데이터 전송의 관점에서 읽기 전송과 쓰기 전송으로 구분할 수 있다. 본 논문에서는 이들 읽기 전송과 쓰기 전송에 소요되는 시간을 최소화하는 방법을 제안하였는데, 이때 쓰기 전송에 소요되는 시간은 400n sec 이며, 읽기 전송에 소요되는 시간은 최소 400n sec 이다.

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Sensorless Control of Non-salient Permanent Magnet Synchronous Motor Drives using Rotor Position Tracking PI Controller

  • Lee Jong-Kun;Seok Jul-Ki
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • v.5B no.2
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    • pp.189-195
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    • 2005
  • This paper presents a new velocity estimation strategy for a non-salient permanent magnet synchronous motor drive without high frequency signal injection or special PWM pattern. This approach is based on the d-axis current regulator output voltage of the drive system, which contains the rotor position error information. The rotor velocity can be estimated through a rotor position tracking PI controller that controls the position error at zero. For zero and low speed operation, the PI gain of the rotor position tracking controller has a variable structure according to the estimated rotor velocity. Then, at zero speed, the rotor position and velocity have sluggish dynamics because the varying gains are very low in this region. In order to boost the bandwidth of the PI controller during zero speed, the loop recovery technique is applied to the control system. The PI tuning formulas are also derived by analyzing this control system by frequency domain specifications such as phase margin and bandwidth assignment.

Investigation of the Effect of new alignment in NLC by using Dipping Effect (침지효과를 이용한 신액정배향효과에 관한 연구)

  • Lee, Jeong-Ho;Park, Tae-Kyu;Seo, Dae-Shik
    • Proceedings of the KIEE Conference
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    • 1999.07d
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    • pp.1815-1817
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    • 1999
  • In this paper, the generation of high pretilt angle in nematic liquid crystal (NLC) by dipping effect on three kinds of the rubbed polyimide (PI) surface was investigated. The generated pretilt angle of NLC increases due to dipping effect before rubbing treatment on two kinds of the rubbed PI surface with side chain. The generated pretit angle in NLC by using dipping effect after rubbing treatment on PI surface with short side chain is high compared to the PI surface with long side chain. The generated pretit angle of the positive type NLC $(\Delta{\varepsilon}>0)$ is higher as than that of the negative type NLC $({\Delta}{\varepsilon}<0)$ by using dipping effect before rubbing treatment on homeotropic layer. The generated pretilt angle of NLC is attributed to perpendicular component of permittivity ${\varepsilon}_{\perp}$ of NLC on rubbed PI surface.

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Study on of polarity effect on alignment film in transcription-aligned TN-LCD (전사배향 TN-LCD 에서의 배향막의 극성효과에 관한 연구)

  • Kim, Jin-Ho;Seo, Dae-Shik
    • Proceedings of the KIEE Conference
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    • 1999.07d
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    • pp.1812-1814
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    • 1999
  • The effects of polarity of the polymer on transcription-aligned twisted nematic (TN)-liquid crystal display (LCD) on various the polyimide (PI) surfaces were investigated. The monodomain alignment of nematic (N)LC is obtained in cells fabricated by transcription alignment method on PI surface with medium polarity. The LC alignment using transcription alignment method is attributed to polarity of the polymer. The threshold voltage of transcription-aligned TN-LCD decreases with increasing the polarity of the polymer on three kinds of the PI surfaces. The threshold voltage of transcription-aligned TN-LCD on PI surface with high polarity is almost the same compared to rubbing-aligned TN-LCD. The response time of transcription-aligned TN-LCD decreases with the increasing the polarity of the polymer on all PI surfaces. The decay time of transcription-aligned TN-LCD is slow compared with the rubbing-aligned TN-LCD.

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The Design of Library System using the Cloud Environment Based on the Raspberry pi

  • Park, Sungbin;Lee, Jong-Yong;Jung, Kye-Dong
    • International journal of advanced smart convergence
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    • v.4 no.1
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    • pp.31-34
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    • 2015
  • Recently, the various types of data are began to increase. In order to manage the data efficiently, a variety of cloud services are being made. However, while providing a cloud service, the problem is the cost and waste a lot of human power to manage the data that is generated and managed by the server. To solve this problem, it is build the cloud environment using a single board computer with Raspberry pi. In this paper, we used Raspberry pi as a cloud server to provide services for the users. And we construct a Total Server to manage the generated data. It can separate the processing of data and the provision of services. We ensure the efficient operation by building a cloud environment with Raspberry pi and by managing the data which generated in cloud environment with the total server.

Study on Laser irradiation characteristics for Oxide TFTs on Flexible Substrate (산화물 반도체 Flexible Display 소자 제작을 위한 Laser 가공 특성 연구)

  • Son, Hyeok;Lee, Gong-Su;Jeong, Han-Uk;Kim, Gwang-Yeol;Choe, Yeong-Deok
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.11a
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    • pp.203-203
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    • 2009
  • Low temperature annealing for oxide TFTs including IGZO on PI substrate is the essential process to fabricate flexible display devices, since low heat-resistance on PI and PEN substrates limits the temperature range. Laser annealing is one of the promising candidates for low temperature process, and it has been used for various application in semiconductor and LCD fabrication. We irradiated laser to solution-based IGZO thin films on PI substrate were irradiated to laser beam, and investigated laser damage of PI layer. Based on transmittance analysis, wavelength(532nm) and scan speed(1000mm/s) is the optimized condition for laser irradiation about ink-Jet printed oxide TFTs on PI substrates.

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A Study on ${\pi}$/4-DQPSK with Nonredundant Multiple Error Correction

  • Song, Seog-Il;Han, Young-Yearl
    • ETRI Journal
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    • v.21 no.2
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    • pp.9-21
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    • 1999
  • In this paper, to enhance the performance of ${\pi}$/4-DQPSK (${\pi}$/4-differential quadrature phase shift keying), the scheme using nonredundant multiple error correction is proposed and investigated. This scheme for the differential detection of ${\pi}$/4-DQPSK uses the signal output which is delayed for more than two time slots as the parity check bit and applies it to nonredundant multiple error correction. The proposed system was used for studying the performance of ${\pi}$/4-DQPSK with Nonredundant Error Correction (NEC) in additive white Gaussian noise (AWGN) and Nakagami fade modeled mobile communication channel, and it was observed that the performance increased as the error correction capability increased.

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Fault diagnosis using multiple PI observers

  • Kim, Hwan-Seong;Ki, Sang-Bong;Kawaji, Shigeyasu
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10a
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    • pp.287-290
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    • 1996
  • Fault diagnosis problem is currently the subject of extensive research and numerous survey paper can be found. Although several works are studied on the fault detection and isolation observers and the residual generators, those are concerned with only the detection of actuator failures or sensor failures. So, the perfect detection and isolation is strongly required for practical applications. In this paper, a, strategy of fault diagnosis using multiple proportional integral (PI) observers including the magnitude of actuator failures is provided. It is shown that actuator failures are detected and isolated perfectly by monitoring the integrated error between actual output and estimated output by a PI observer. Also in presence of complex actuator and sensor failures, these failures are detected and isolated by multiple PI observers.

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