A method is described for the establishment of a nonlinear differential equation which acts as a model for an actual physical system. It is assumed initially that the actual system contains only a single nonlinear element and that this element may be represented in the differential equation model by a single-valued nonlinear function of a single variable. The method is then extended to systems which contain several nonlinear elements. It is assumed that the system may be excited by a specified periodic input and that neither the input nor the output of the system is significantly corrupted by noise. An experimental criterion is given for the range of periodic inputs which permit satisfactory determination of the differential equation model.

A Method for the Determination of a Differential Equation Model for Simple Nonlinear Systems

Fault Identification of a Motor-Pump System Using Parameter Estimation and Pattern Classification

Fault Detection in a Tubular Heat Exchanger based on Modelling and Parameter Estimation

In this thesis, the operational amplifier is defined and analyzed in circuit applications from the viewpoint of a network theoreisto This leads to an equivalence theorem relating different types of infinite gain controlled sources, A number of active synthesis techniques utilizing the operational amplifier are discussed. Several ideal devices are realized using the operational amplifier. Noteworthy among these are a negative-immittance converter realization using a single operational amplifier and a number of gyrator circuits. It is concluded that the operational amplifier should be more seriously considered for use in non-computer circuit applications. ACKNOWLEDGMENT The author would like to express his sincere appreciation to Dr, L. P. Huelsman for his helpful criticisms and suggestions regarding the writing of this thesis.

The use of operational amplifiers in active network theory

Fault identification using a discrete square root method

The study of dynamic systems on an analog computer often involves the synthesis of complex transfer functions. Techniques from the field of network synthesis are combined with methods used in electronic-differential-analyzer work to provide effective means for realizing these transfer functions with a minimum of computer equipment. The basic ideas of associating high-gain amplifiers and phase-inverting amplifiers with resistor-capacitor networks are applied in order to obtain three systematic methods for synthesizing transfer functions of various degrees of complexity. The methods described are illustrated by an example.

M. V. Mathews

Papers

Transfer-function synthesis with computer amplifiers and passive networks