• Title, Summary, Keyword: Gain Scaling

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Design of Fuzzy Scaling Gain Controller using Genetic Algorithm

  • Hyunseok Shin;Lee, Sungryul;Hyungjin Kang;Cheol Kwon;Park, Mignon
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • pp.474-478
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    • 1998
  • This paper proposes a method which can resolve the problem of exisiting fuzzy PI controller using optimal scaling gains obtained by genetic algorithm. The new method adapt a fuzzy logic controller as a high level controller to perform scaling gain algorithm between two pre-determined sets.

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Design of Fuzzy Scaling Gain Controller using Genetic Algorithm (유전자 알고리즘을 이용한 퍼지 스케일링 게인 제어기의 설계)

  • Shin, Hyun-Seok; Kho, Jae-Won;Kwon, Cheol;Park, Mig-Non
    • Proceedings of the KIEE Conference
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    • pp.2268-2271
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    • 1998
  • This paper proposes a method which can resolve the problem of existing fuzzy Pl controller using optimal scaling gains obtained by genetic algorithm. The new method adapt a fuzzy logic controller as a high level controller to perform scaling gain algorithm between two pre-determined sets.

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An Adaptive Maximum Power Point Tracking Scheme Based on a Variable Scaling Factor for Photovoltaic Systems (태양광 시스템을 위한 가변 조정계수 기반의 적응형 MPPT 제어 기법)

  • Lee, Kui-Jun;Kim, Rae-Young;Hyun, Dong-Seok;Lim, Chun-Ho;Kim, Woo-Chull
    • The Transactions of the Korean Institute of Power Electronics
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    • v.17 no.5
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    • pp.423-430
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    • 2012
  • An adaptive maximum power point tracking (MPPT) scheme employing a variable scaling factor is presented. A MPPT control loop was constructed analytically and the magnitude variation in the MPPT loop gain according to the operating point of the PV array was identified due to the nonlinear characteristics of the PV array output. To make the crossover frequency of the MPPT loop gain consistent, the variable scaling factor was determined using an approximate curve-fitted polynomial equation about linear expression of the error. Therefore, a desirable dynamic response and the stability of the MPPT scheme were maintained across the entire MPPT voltage range. The simulation and experimental results obtained from a 3 KW rated prototype demonstrated the effectiveness of the proposed MPPT scheme.

The Design of IMC-PID Controller Considering a Phase Scaling Factor (위상 조절 인자를 고려한 IMC-PID 제어기의 설계)

  • Kim, Chang-Hyun;Lim, Dong-Kyun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.9
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    • pp.1618-1623
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    • 2008
  • In this paper, a new design method for IMC-PID that adds a phase scaling factor of system identifications to the standard IMC-PID controller as a control parameter is proposed. Based on analytically derived frequency properties such as gain and phase margins, this tuning rule is an optimal control method determining the optimum values of controlling factors to minimize the cost function, integral error criterion of the step response in time domain, in the constraints of design parameters to guarantee qualified frequency design specifications. The proposed controller improves existing single-parameter design methods of IMC-PID in the inflexibility problem to be able to consider various design specifications. Its effectiveness is examined by a simulation example, where a comparison of the performances obtained with the proposed tuning rule and with other common tuning rules is shown.

Control of Electromagnetic Levitation System using ε-scaling Partial State Feedback Controller (ε조절 요소를 가진 부분 상태 궤환 제어기를 이용한 자기부상 시스템의 제어)

  • Park, Gyu-Man;Choi, Ho-Lim
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.8
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    • pp.1572-1576
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    • 2011
  • The electromagnetic levitation(EMS) system is one of the well-known nonlinear system because of its nonlinearity and several control techniques have been proposed. We propose an ${\epsilon}$-scaling partial feedback controller for the ball position control of the EMS system. The key feature of our proposed controller is the use of the scaling factor ${\epsilon}$ which provides a function of controller gain tuning along with robustness. In this paper, we show the stability analysis of our proposed controller and the convergence analysis of the state observer in terms of ${\epsilon}$-scaling factor. In addition, the experimental results show the validity of the proposed controller and improved control performance over the conventional PID controller.

Performance and Convergence Analysis of Tree-LDPC codes on the Min-Sum Iterative Decoding Algorithm (Min-Sum 반복 복호 알고리즘을 사용한 Tree-LDPC의 성능과 수렴 분석)

  • Noh Kwang-seok;Heo Jun;Chung Kyuhyuk
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.1C
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    • pp.20-25
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    • 2006
  • In this paper, the performance of Tree-LDPC code is presented based on the min-sum algorithm with scaling and the asymptotic performance in the water fall region is shown by density evolution. We presents that the Tree-LDPC code show a significant performance gain by scaling with the optimal scaling factor which is obtained by density evolution methods. We also show that the performance of min-sum with scaling is as good as the performance of sum-product while the decoding complexity of min-sum algorithm is much lower than that of sum-product algorithm. The Tree-LDPC decoder is implemented on a FPGA chip with a small interleaver size.

Scaling of ground motions from Vrancea (Romania) earthquakes

  • Pavel, Florin;Vacareanu, Radu
    • Earthquakes and Structures
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    • v.11 no.3
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    • pp.505-516
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    • 2016
  • This paper evaluates the scaling of ground motions recorded from nine intermediate-depth earthquakes produced in the Vrancea seismic zone in Romania. The considered ground motion database consists of 363 horizontal recordings obtained on soil classes B and C (according to Eurocode 8). An analysis of the inter- and intra-event spectral accelerations is performed in order to gain information regarding the magnitude and distance scaling of the Vrancea ground motions. The analyses reveal a significant influence of the earthquake magnitude and focal depth on the distance scaling and different magnitude and distance scaling for the two soil classes. A linear magnitude and distance scaling is inferred from the results for the range of magnitudes $5.2{\leq}M_W{\leq}7.1$. The results obtained are checked through stochastic simulations and the influence of the stress drop and kappa values on the ground motion levels is assessed. In addition, five ground motion models which were tested in other studies using recordings from Vrancea earthquakes are analyzed in order to evaluate their corresponding host stress drop and kappa. The results show generally a direct connection between the host kappa values and the host stress drop values. Moreover, all the ground motion models depict magnitude dependent host kappa and stress drop levels.

An Effective Viewport Resolution Scaling Technique to Reduce the Power Consumption in Mobile GPUs

  • Hwang, Imjae;Kwon, Hyuck-Joo;Chang, Ji-Hye;Lim, Yeongkyu;Kim, Cheong Ghil;Park, Woo-Chan
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.11 no.8
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    • pp.3918-3934
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    • 2017
  • This paper presents a viewport resolution scaling technique to reduce power consumption in mobile graphic processing units (GPUs). This technique controls the rendering resolution of applications in proportion to the resolution factor. In the mobile environment, it is essential to find an effective resolution factor to achieve low power consumption because both the resolution and power consumption of a GPU are in mutual trade-off. This paper presents a resolution factor that can minimize image quality degradation and gain power reduction. For this purpose, software and hardware viewport resolution scaling techniques are applied in the Android environment. Then, the correlation between image quality and power consumption is analyzed according to the resolution factor by conducting a benchmark analysis in the real commercial environment. Experimental results show that the power consumption decreased by 36.96% on average by the hardware viewport resolution scaling technique.

An Output Feedback Controller for a Ball and Beam System under Measurement Noise of Feedback Sensor (센서에 측정에러가 있는 볼-빔 시스템의 출력 궤환 제어기)

  • Kim, Hyun-Do;Choi, Ho-Lim
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.10
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    • pp.955-959
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    • 2011
  • In this paper, we assume that an output sensor of a ball and beam system is coupled with AC measurement noise. We propose an output feedback controller for a ball and beam system under measurement noise of feedback sensor. Measurement noise makes feedback signals distorted, and results in performance degradation or even system failure. Therefore, we need to design a robust controller to accommodate the possible measurement noise in the feedback information. Our controller is equipped with a gain-scaling factor to minimize the effect of measurement noise in output feedback information. We give an analysis of the controlled system and illustrate the improved control performance via simulation and experiment for a ball and beam system.

Design and Analysis of an Output Feedback Controller for a Chain of Integrators System Compensating Measurement Noise of Feedback Sensor (적분기 시스템에서 센서의 측정에러를 보상하는 출력 궤환 제어기 설계 및 분석)

  • Kim, Hyun-Do;Choi, Ho-Lim
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.4
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    • pp.299-303
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    • 2011
  • In this paper, we propose an output feedback controller for a chain of integrators system compensating measurement noise of feedback sensor. Measurement noise makes feedback signals distorted, and results in performance degradation or even system failure. Therefore, we need to design a robust controller to accommodate the possible measurement noise in the feedback information. Our controller is equipped with a gain-scaling factor to reject or minimize the effect of measurement noise in output feedback information. We give a theoretical analysis of the controlled system and illustrate the improved control performance via an example.