• 제목/요약/키워드: Zeros

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DIFFERENTIAL EQUATIONS AND ZEROS FOR NEW MIXED-TYPE HERMITE POLYNOMIALS

  • JUNG YOOG KANG
    • Journal of applied mathematics & informatics
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    • 제41권4호
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    • pp.869-882
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    • 2023
  • In this paper, we find induced differential equations to give explicit identities of these polynomials from the generating functions of 2-variable mixed-type Hermite polynomials. Moreover, we observe the structure and symmetry of the zeros of the 2-variable mixed-type Hermite equations.

종속형제어기의 영점의 영향을 고려한 저차제어기의 설계: 특성비지정 접근법 (A Design Method Reducing the Effect of Zeros of a Cascaded Three-Parameters Controller: The Characteristic Ratio Assignment Approach)

  • 김려화;이관호;김영철
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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    • pp.158-160
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    • 2005
  • This paper presents a new approach to the problem of designing a cascaded three-parameters controller for a given linear time invariant (LTD plant in unity feedback system. We consider a proportional-integral-derivative (PID) and a first-order controller with specified overshoot and settling time. This problem is difficult to solve because there may be no analytical solution due to the use of low-order controller and furthermore. the zeros of controller just appear in the zeros of feedback system. The key idea of our method is to impose a constraint on the controller parameters so that the zeros of resulting controller are distant from the dominant pole of closed-loop system to the left as far as the given interval. Two methods realizing the idea are suggested. We have employed the characteristic ratio assignment (CRA) in order to deal with the time response specifications. It is noted that the proposed methods are accomplished only in parameter space. Several illustrative examples are given.

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Closed Queueing Networks and Zeros of Successive Derivatives

  • Namn, Su-Hyeon
    • 한국경영과학회지
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    • 제22권1호
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    • pp.101-121
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    • 1997
  • Consider a Jackson type closed queueing network in which each queue has a single exponential server. Assume that N customers are moving among .kappa. queues. We propose a candidata procedure which yields a lower bound of the network throughput which is sharper than those which are currently available : Let (.rho.$_{1}$, ... .rho.$_{\kappa}$) be the loading vector, let x be a real number with 0 .leq. x .leq. N, and let y(x) denote that y is a function of x and be the unique positive solution of the equation. .sum.$_{i = 1}$$^{\kappa}$y(x) .rho.$_{i}$ (N - y(x) x $p_{i}$ ) = 1 Whitt [17] has shown that y(N) is a lower bound for the throughput. In this paper, we present evidence that y(N -1) is also a lower bound. In dosing so, we are led to formulate a rather general conjecture on 'quot;Migrating Critical Points'quot; (MCP). The .MCP. conjecture asserts that zeros of successive derivatives of certain rational functions migrate at an accelerating rate. We provide a proof of MCP in the polynomial case and some other special cases, including that in which the rational function has exactly two real poles and fewer than three real zeros.tion has exactly two real poles and fewer than three real zeros.

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종속형제어기의 영점의 영향을 고려한 3-파라미터 제어기의 설계: 특성비지정 접근법 (A Design Method Reducing the Effect of Zeros of a Cascaded Three-Parameters Controller: The Characteristic Ratio Assignment Approach)

  • 진이화;이관호;김영철
    • 대한전기학회논문지:시스템및제어부문D
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    • 제55권1호
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    • pp.20-23
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    • 2006
  • This paper presents a new approach to the problem of designing a cascaded three-parameters controller for a given linear time invariant (LTI) plant in unity feedback system. We consider a proportional-integral-derivative (PID) and a first-order controller with the specified overshoot and settling time. This problem is difficult to solve because there may be no analytical solution due to the use of low-order controller. Furthermore, the zeros of controller just appear in the zeros of feedback system. The key idea of our method is to impose a constraint on the controller parameters so that the zeros of resulting controller are distant from the dominant pole of closed-loop system to the left as far as the given interval. Two methods realizing the idea are suggested. We have employed the characteristic ratio assignment (CRA) in order to deal with the time response specifications. It is noted that the proposed methods are accomplished only in parameter space. Several illustrative examples are given.