• Title/Summary/Keyword: 감쇠 지연

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An Auto-tuning of PID Controller using Fuzzy Performance Measure and Neural Network for Equipment System (전력설비시스템을 위한 퍼지 평가함수와 신경회로망을 사용한 PID제어기의 자동동조)

  • 이수흠;박현태;이내일
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.13 no.2
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    • pp.63-70
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    • 1999
  • This paper is proposed a new method to deal with the optimized auto-tuning for the Pill controller which is used to the process-control in various fields. First of all, in this method, 1st order delay system with dead time which is modelled from the unit step response of the system is Pade-approximated, then initial values are determined by the Ziegler-Nichols method. So we can find the parameters of Pill controller so as to minimize the fuzzy criterion function which includes the maximum overshoot, damping ratio, rising time and settling time. Finally, after studying the parameters of Pill controller by Backpropagation of Neural-Network, when we give new K, L, T values to Neural-Network, the optimized parameter of Pill controller is found by Neural-Network Program.rogram.

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The Design of Phase Angle Controller Reducing Sub-harmonic Current for Universal Motor in Vacuum Cleaner (진공청소기용 유니버셜모터의 고조파전류 저감 위상각제어기 설계)

  • 임홍우;장용해;백형래
    • The Transactions of the Korean Institute of Power Electronics
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    • v.7 no.3
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    • pp.237-243
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    • 2002
  • The single phase angle control system may become noisy when speed Is modulated with a conventional TRIAC AC controller. But this system is widely used despise of occurring sub-harmonic current because of its simply structure and low cost. Most of the vacuum cleaner drive control system regulates TRIAC's phase angle, so that it is controlled the speed. In the case of marketing product, it is not considered linearity of the speed to minimize occurring harmonic current. The sub-harmonic current reduces effectively in regulating specification TRIAC trigger phase angle. In this paper, we examined about characteristics of phase angle controller and parameter of parallel coil for eliminating sub-harmonic current.

Performance Analysis of Short Range Inter-Vehicle DS/CDMA Communication System (근거리 차량간 DS/CDMA 통신시스템의 성능 분석)

  • Oh, Se-Kab;Kang, Heau-Joh;Choi, Yong-Surk;Cho, Sung-Joon
    • Journal of Advanced Navigation Technology
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    • v.4 no.2
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    • pp.143-151
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    • 2000
  • In this paper, short range IVC(Inter-Vehicle Communication) channel is modeled in three kinds considering rain attenuation and oxygen absorption. And the performance of DS/CDMA communication system in one path Rician model suitable for platton driving which is the final goal of AVHS(Advanced Vehicle & Highway System) is analyzed. Also, the reflection coefficients in 60 GHz is calculated. For the performance improvement both BCH channel coding and MRC diversity reception technique are adopted. The BER performance is evaluated as a function of packet length, Rician depth and the distance between vehicles.

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Numerical Analysis for Modeling of Sound Absorbing Medium using Transmission Line Matrix Modeling (전달선로행렬법을 이용한 흡음재 모델링에 대한 수치해석)

  • Park, Kyu-Chil;Yoon, Jong-Rak
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.8
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    • pp.1599-1605
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    • 2012
  • We introduced an approach of modeling of a sound absorbing medium that had different absorbing coefficient according to frequency. To obtain the time domain result of the frequency characteristics of a sound absorbing medium, transmission line matrix modeling was used. To input sound absorbing effect in TLM modeling, we added a FIR filter at a node instead of absorbing component using resistance component. There were simulated the characteristics of time-shift, low pass filter, high pass filter using the FIR filter with 7-tap coefficients, then compared with theoretical results. From various simulation results, we could find that added FIR filter coefficient in TLM modeling was an useful way to model a sound absorbing medium.

Performance Improvement of PMSM Current Control using Gain Attenuation and Phase Delay Compensated LPF (이득 감쇠 및 위상 지연 보상 LPF를 이용한 PMSM의 전류 제어 성능 개선)

  • Kim, Minju;Choi, Chinchul;Lee, Wootaik
    • Transactions of the Korean Society of Automotive Engineers
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    • v.22 no.2
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    • pp.107-114
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    • 2014
  • This paper applies a compensated low pass filter (LPF) to current measurements for permanent magnet synchronous motor (PMSM) drives. The noise limits the bandwidth of current controllers and has more adverse influences on control performances under the light load condition because of the low signal-to-noise ratio. In order to eliminate the noise sensitivity, this paper proposes a digital LPF with a compensator of gain attenuation and phase delay which are unacceptable in current information for PMSM drives. Characteristics of the proposed LPF are analyzed in comparison with the general LPFs. The compensated LPF is basically designed by the orthogonal property of the measured currents in the ${\alpha}{\beta}$ stationary reference frame. In addition, an implementation issue of the proposed method is discussed. Experimental results using the proposed method show improvements of the current control performance from two perspectives, rapid step responses and reductions of harmonic distortion.

A Study on the Diesel Flame by Means of Image Analysis ofn Shadow Photographs (음영사진의 화상해석에 의한 디젤화염에 관한 연구)

  • 장영준;박호준;신본무정
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.14 no.5
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    • pp.1222-1233
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    • 1990
  • The formation and oxidation processes of soot particles in a diesel flame were investigated with a rapid compression machine. A cloud of soot particles was successfully visualized by means of the instantaneous laser shadow photographs technique and the equivalence ratio of the soot formation zone was estimated from a measured fuel concentration distribution in a nonevaporating spray. The temporal and spatial variation of soot concentration in the flame was also correlated with the rate of heat release. Soot particles appears first in a region near the flame tip when diffusion combustion period starts, and its concentration is a maximum at about the end of injection, then decreases due to oxidation. The reason for soot being formed in a fuel lean region near the flame tip is the evaporated fuel requires time to be pyrolized as it travels through the burning fuel rich zone towards the flame tip.

A Study of VLC Channel Modeling using user Location Environment (사용자 위치 기반의 VLC 채널 모델 도출에 관한 연구)

  • Lee, Jung-Hoon;Cha, Jae-Sang
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.10B
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    • pp.1240-1245
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    • 2011
  • In this paper, channel modeling and analysis of wireless visible light communication(VLC) were studied in indoor circumstance. Photons emitted from LED straightly moved and navigated within indoor, after that a part of photons reached on PD via LOS(Line Of Sight) or NLOS(None Line Of Sight). These received signals had characteristics of delay profile and attenuation, which was multiple-path fading. In this paper, computer simulation of VLC channel was executed under the condition that two LEDs were used for transmitter and three PDs were located at different positions of the 20*8*2.3m sized indoor. BER performance simulation was excuted based on the characteristics of each VLC channel.

A Study of Multiple Scattering Model by Analytic Method for Southeastern Korea (한반도 남동부지역의 해석적방법에 의한 다중산란모델 연구)

  • Chung, Tae-Woong
    • Geophysics and Geophysical Exploration
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    • v.14 no.3
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    • pp.242-248
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    • 2011
  • By applying analytic method to the uniform model, the intrinsic and scattering quality factor ($Q_i^{-1}$ and $Q_s^{-1}$) was separated for the southeastern part of Korean Peninsula. The Multiple Lapse Time Window Analysis method was used to fit theoretical values with observations obtained 759 earthquake data. While previous study for the Korean Peninsula showed very low $Q_i^{-1}$ and $Q_s^{-1}$ reflecting inactive seismicity, southeastern Korea exhibited relatively high $Q_i^{-1}$ and $Q_s^{-1}$ values interpreted as higher seismicity than the other region in the peninsula.

An Auto-tuning of PID Controller using Fuzzy Criterion Function (퍼지 평가함수를 사용한 PID제어기의 자동 동조)

  • 류상욱;김봉재;정광조;정원용;이수흠
    • The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.8 no.3
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    • pp.64-70
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    • 1994
  • We propose a new method to deal with optimal auto-tuning of the PID controller which is used to process control in various fields. First of all, in this method, 1st order system which was modeled from the unit step response of the system is Pade-approximated, then initial values are determined by the Ziegler-Nichols method. Finally, we can find the parameters of PID controller so as to maximize the fuzzy criterion function which includes the maximum overshoot, damping ratio, rising time and settling time. The Proposed method also shows good adaptability for variations in characteristics and dead m e of the system.

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Performance Analysis on Code-Division Multiple Access in Underwater Acoustic Sensor Network (수중 음향 센서 망에서의 코드 분할 다중 접속 기법에 대한 성능 해석)

  • Seo, Bo-Min;Cho, Ho-Shin
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.9A
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    • pp.874-881
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    • 2010
  • Acoustic signal, which is a main carrier of underwater communication, attenuates along the traveled path heavily depending on the frequency as well as inter-node distance. In addition, since it has a long propagation delay, the conventional medium access control (MAC) schemes requiring complex signaling procedures and accordingly heavy overhead messages would not be appropriate in underwater communications. In this paper, we propose a code division multiple access (CDMA) scheme as a solution for MAC of underwater communication and evaluate the performance. A hierarchical data-gathering tree topology is considered and a staggered wake-up pattern is employed for the purpose of energy saving. As a performance measure, the data rate at each level of hierarchical topology is derived.