John Leth

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This paper addresses the problem of planning the usage of actuators optimally in an economic perspective. The objective is to maximize the profit of operating a given plant during 24 hours of operation. Models of two business objectives are formulated in terms of system states and the monetary value of these objectives is established. Based on these and the(More)
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This paper considers the problem of economical optimization of the power production in a power plant capable of utilizing three different fuel systems. The considered fuel systems are coal, gas, and oil; each has certain advantages and disadvantages e.g. gas is easier to control than coal but it is more expensive. A profit function is stated and an analysis(More)
This paper deals with stability analysis of hybrid systems. Various stability concepts related to hybrid systems are introduced. The paper advocates a local analysis. It involves the equivalence relation generated by reset maps of a hybrid system. To establish a tangible method for stability analysis, we introduce the notion of a chart, which locally(More)
In this paper a state observer for a distributed parameter system (DPS) with nonconstant parameter functions is presented. The DPS describes the freezing of foodstuff in vertical plate freezers and is a nonlinear heat equation. The observer is based upon the Extended Kalman Filter, meaning that the nonlinear heat equation has been discretized in the spatial(More)
In this work the stability properties of a nonlinear partial differential equation (PDE) with state-dependent parameters is investigated. Among other things, the PDE describes freezing of foodstuff, and is closely related to the (Potential) Burgers' Equation. We show that for certain forms of coefficient functions, the PDE converges to a stationary solution(More)