• Title/Summary/Keyword: discrete delay

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Cognitive Biases in Perceiving Feedback LooP Dominance

  • Kim, Dong-Hwan;Kim, Byung-Kwan
    • Korean System Dynamics Review
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    • v.5 no.1
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    • pp.127-142
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    • 2004
  • Feedback loop dominance is a key concept to understand structural driving forces of system behavior. In this paper, we propose two kinds of shifts in dominant feedback loops: continuous shifts (CS) and discrete shifts (DS). With the help of questionnaires, we verified three hypotheses regarding cognitive biases in perceiving the shifts in dominant feedback loops: 1) failure in perceiving continuous shifts, 2) tendency of decision making based on discrete shifts, and 3) different perception on the dominant feedback loops between level variables and rate variables. We discussed the implication of these cognitive biases on time delay and timing strategy in decision-making processes.

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Robust $H_{\infty}$ Control of Discrete Uncertain Systems with Time Delays in States and Control Inputs (상태와 제어입력에 시간지연을 가지는 이산 불확실성 시스템의 견실 $H_{\infty}$ 제어)

  • Jong Hae Kim;Hong Bae Park
    • Journal of Institute of Control, Robotics and Systems
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    • v.4 no.6
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    • pp.689-694
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    • 1998
  • 본 논문에서는 상태와 제어입력에 시간지연을 가지는 이산 불확실성 시스템의 견실 H/sub ∞/ 상태궤환 제어기 설계문제를 다룬다. 동일한 제어기에 대해서, 파라미터 불확실성을 가지는 시간지연 시스템이 자승적 안정성(quadratic stability)과 폐루프 시스템의 H/sub ∞/ 노옴의 한계를 유지하면서 파라미터 불확실성이 없는 등가의 시스템으로 변형된다. 그리고 주어진 이산 불확실성 시간지연 시스템의 견실 H/sub ∞/ 상태궤환 제어기가 존재할 충분조건과 제어기 설계 알고리듬을 제시한다. 또한 변수치환과 Schur 여수(complement) 정리를 이용하면 구한 충분조건은 LMI(linear matrix inequality) 형태로 쓸 수 있다. 예제를 통하여 제시한 결과의 타당성을 보인다.

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Sampled Fuzzy Controller for discrete networked control systems (샘플치 퍼지 제어기를 이용한 이산 퍼지 시스템 제어)

  • Kook, Song-Min;Bae, Park-Jin;Kim, Jong-Seon;Hoon, Joo-Young
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.1783-1784
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    • 2008
  • This paper presents a novel control technique to deal with networked control systems with neutral timedelay, which is known to highly degrade the control performance of the controlled system. The stability analysis and design method for a sampled-data fuzzy controller for discrete networked control systems (NCS). The neutral time-delay and sampling activity will complicate the NCS. And it make the stability analysis much more difficult than that for a continuous-time NCS. Based on the fuzzy control approach, linear matrix inequality (LMI)-based stability conditions are derived to guarantee the neutral T-S fuzzy system stability. The simulation results and practical experiments illustrate that the proposed controller design is realistic.

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Evaluation of network protocols for automotive data communication (차량용 데이터 통신을 위한 네트워크 프로토콜의 평가)

  • Yun, Jung-A;Nam, Sang-Woon;Kim, Kee-Woong;Lee, Suk
    • Journal of Institute of Control, Robotics and Systems
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    • v.3 no.6
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    • pp.632-638
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    • 1997
  • The growing number of electronic components used in automobiles has given rise to problems concerning the increasing number, size and weight of the wiring harnesses. As an approach to resolve these problems, multiplexed wiring systems using automotive communication protocol such as Controller Area Network(CAN), Advanced PALMNET and J1850 have been developed by many automobile companies. In order to compare these protocols quantitatively, this paper presents the performance evaluation of CAN and Advanced PALMNET via discrete event simulation. Through numerous simulation experiments, several important quantitative performance factors such as the probability of a transmission failure, average system delay(data latency), and throughput have been evaluated.

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A Calibration Technique for Array antenna based GPS Receivers (배열 안테나 기반 GPS 수신기에서의 교정 방안)

  • Kil, Haeng-bok;Joo, Hyun;Lee, Chulho;Jeong, Eui-Rim
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.22 no.4
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    • pp.683-690
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    • 2018
  • In this paper, a new signal processing technique is proposed for calibrating gain, phase, delay offsets in array antenna based anti-jamming minimum variance distortionless response (MVDR) global-positioning-system (GPS) receivers. The proposed technique estimates gain, phase and delay offsets across the antennas, and compensates for the offsets based on the estimates. A pilot signal with good correlation characteristics is used for accurate estimation of the gain, phase and delay offsets. Based on the cross-correlation, the delay offset is first estimated and then gain/phase offsets are estimated. For fine delay offset estimation and compensation, an interpolation technique is used, and specifically, the discrete Fourier transform (DFT) is employed for the interpolation technique to reduce the computational complexity. The proposed technique is verified through computer simulation using MATLAB. According to the simulation results, the proposed technique can reduce the gain, phaes and delay offset to 0.01 dB, 0.05 degree, and 0.5 ns, respectively.

Removal of Complexity Management in H.263 Codec for A/VDelivery Systems

  • Jalal, Ahmad;Kim, Sang-Wook
    • 한국HCI학회:학술대회논문집
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    • 2006.02a
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    • pp.931-936
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    • 2006
  • This paper presents different issues of the real-time compression algorithms without compromising the video quality in the distributed environment. The theme of this research is to manage the critical processing stages (speed, information lost, redundancy, distortion) having better encoded ratio, without the fluctuation of quantization scale by using IP configuration. In this paper, different techniques such as distortion measure with searching method cover the block phenomenon with motion estimation process while passing technique and floating measurement is configured by discrete cosine transform (DCT) to reduce computational complexity which is implemented in this video codec. While delay of bits in encoded buffer side especially in real-time state is being controlled to produce the video with high quality and maintenance a low buffering delay. Our results show the performance accuracy gain with better achievement in all the above processes in an encouraging mode.

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A Study of the Compression for the Power Quality Disturbance Signal by using the Phase Estimation of Stationary Signal (정상신호의 위상 추정을 이용한 전력 품질 왜곡 신호의 압축에 관한 연구)

  • Chung, Young-Sik;Park, Chan-Woong
    • Proceedings of the KIEE Conference
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    • 2005.07a
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    • pp.341-343
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    • 2005
  • This paper introduces a compression algorithm for power quality disturbance signal via the discrete wavelet transform, DWT. Algorithm to estimate a time delay from the power quality disturbance signal is proposed. Pseudo-stationary signal is constructed from the estimated time delay. A difference signal or nonstationary signal is obtained by removing a pseudo-stationary signal from a disturbance signal. DWT is applied to a difference signal. The threshold is applied to reduce a number of coefficients. Simulation results show the resonable compression ratio while keep low signal distortion.

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Fuzzy Robust $H^{\infty}$ Controller Design for Discrete Uncertain Nonlinear Systems with Time Delays (시간지연을 가지는 비선형 불확실성 이산 시스템의 퍼지 견실 $H^{\infty}$ 제어기 설계)

  • 이형호;조상현이갑래박홍배
    • Proceedings of the IEEK Conference
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    • 1998.06a
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    • pp.227-230
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    • 1998
  • In this paper, we propose the design method of fuzzy robust H$\infty$ controller for the uncertain nonlinear discete-time systems with time delay. First, we represent a nonlinear plant with a modified T-S(Takagi-Sugeno) fuzzy model. Then design method utilizing the concept of PDC (parallel distributed compensation) is employed. For the modified T-S fuzzy model with uncertainty and delay, the sufficient condition of the quadratic stabilization with an H$\infty$ norm bound is presented in terms of Lyapunov stability theory and fuzzy robust H$\infty$ controller design method is given by LMI(linear matrix inequality) approach. Also an illustrative example is given to demonstrate the result of the proposed method.

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Modeling of a Continuous-Time System with Time-delay

  • Park, Jong-Jin;Choi, Guy-Seok
    • International Journal of Internet, Broadcasting and Communication
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    • v.4 no.2
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    • pp.1-6
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    • 2012
  • Control Theory for continuous-time system has been well developed. Due to the development of computer technology, digital control scheme are employed in many areas. When delays are in control systems, it is hard to control the system efficiently. Delays by controller-to-actuator and sensor-to-controller deteriorate control performance and could possibly destabilize the overall system. In this paper, a new approximated discretization method and digital design for control systems with multiple state, input and output delays and a generalized bilinear transformation method with a tunable parameter are also provided, which can re-transform the integer time-delayed discrete-time model to its continuous-time model. Illustrative examples are given to demonstrate the effectiveness of the developed method.

A Predictive Controller Based on the Generalized Minimum Variance Approach (일반화 최소분산법을 기초로 한 예측 제어기)

  • 한홍석;양해원
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.37 no.8
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    • pp.557-562
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    • 1988
  • This paper presents a class of discrete adaptive controller that can be applied to a plant without sufficient a priori information. It is well known that the GMV(Generalized Minmum Variance) contrlller performs satisfactorily if the plant time delay is known. By introducing the long-range prediction into the GMV controller, robustness to the time delay can be improved, although optimality is lost. Such an idea motivates a predictive control system to be proposed here, where the system minimizes multi-stage cost via the GMV approach. Moreover, the detuning control weight is determined by an on-line tuning method. It is shown that robustness, computational efficiency, and performance of the resulting control system are improved as compared with those of the GPC(Generalized Predictive Control)system.

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