Now showing items 1-13 of 13

  • Comment on 'biased model reduction by simplified Routh approximation method' 

    Lucas, T. Nigel (Institution of Engineering and Technology, 1989-10)
    For the original article see ibid., vol.23, p.1045-7 (1987). Sastry and Krishnamurthy recently suggested a 'simplified' Routh approximation method (SRAM) for model order reduction of linear systems. They claim that one of ...
  • Comment on Homographic transformation for the simplification of continuous-time transfer functions by Pade approximation 

    Lucas, T. Nigel (Taylor & Francis, 1984)
    It is shown that the homographic transformation method for reducing the order of linear, time-invariant systems produces the same models as the ordinary Pad approximation method about 8 = 0, contrary to what was previously ...
  • Continued-fraction algorithm for biased model reduction 

    Lucas, T. Nigel (Institution of Engineering and Technology, 1983-06)
    An algorithm is presented for linear system reduction which produces biased models such that combinations of retained time moments and Markov parameters may be varied. It is based on the Cauer continued-fraction expansions ...
  • Differentiation reduction method as a multipoint Pade approximant 

    Lucas, T. Nigel (Institution of Engineering and Technology, 1988-01)
    The differentiation method for model order reduction is shown to be a special case of multipoint Pade approximation. This link also extends to other reduction methods where reduced models are generated successively. An ...
  • Least-squares Pade reduction: a nonuniqueness property 

    Lucas, T. Nigel; Smith, I. D. (Institution of Engineering and Technology, 1995-09)
    It is shown that least-squares Pade reduced order models are not unique for a given order. Depending on which reduced denominator coefficient is chosen to be unity. The method is seen to minimise an error index over different ...
  • Linear system reduction by continued-fraction expansion about s = 0 and s = a alternately 

    Lucas, T. Nigel (Institution of Engineering and Technology, 1983-03)
    A method of reduction is given which uses the concept of expanding the system transfer function about the origin and about a general point. This results in good overall responses, and families of reduced models of the same ...
  • Linear system reduction by continued-fraction expansion about three points 

    Lucas, T. Nigel (Institution of Engineering and Technology, 1984-01)
    The method of model reduction by continued-fraction expansion about s = 0 and s = a is extended to include the point s = à ¿ also. This achieves more accurate transient approximations and thus highlights further the ...
  • Linear system reduction by impulse energy approximation 

    Lucas, T. Nigel (Institute of Electrical and Electronics Engineers, 1985-08)
    A method is given for linear system reduction which is a more general form of the Routh method. The reduced models retain stability, and a fuller contribution is made to the impulse response energy of the reduced system ...
  • Linear-system reduction by continued-fraction expansion about a general point 

    Davidson, A. M.; Lucas, T. Nigel (Institution of Engineering and Technology, 1974-07)
    Capacity requirements for multiple-access demand-assigned communication systems are broken down into information, demand and assignment signalling. A simultaneous-transmission scheme for demand signalling greatly reduces ...
  • Model reduction by generalised least-squares method 

    Lucas, T. Nigel; Munro, A. R. (Institution of Engineering and Technology, 1991-07)
    The method of model reduction by least-squares moment matching is generalised to include Markov parameters in the process. This is seen to enhance the flexibility of the method with very little extra computational requirement. ...
  • Scaled impulse energy approximation for model reduction 

    Lucas, T. Nigel (Institute of Electrical and Electronics Engineers, 1988-08)
    It is shown that the impulse energy approximation technique for model reduction can be improved by scaling in the frequency domain. The method remains simple to use and retains the stability property of impulse energy ...
  • Some further observations on the differentiation method of modal reduction 

    Lucas, T. Nigel (Institute of Electrical and Electronics Engineers, 1992-09)
    The differentiation method of model reduction is shown to be equivalent to forming successive ratios of multipoint Taylor polynomial approximation of the numerator and denominator of the transfer function, respectively. ...
  • Stable reduced-order models for discrete-time systems 

    Lucas, T. Nigel (Institution of Engineering and Technology, 1987-01)