0000000000161622

AUTHOR

T. Männikkö

showing 5 related works from this author

Numerical methods to compute sentinels for parabolic systems with an application to source terms identification

1994

We apply the method of sentinels to the identification of source terms in parabolic systems. We present two numerical approaches; the first one is based on the solution of an optimal control problem, and the second one is based on the solution of a linear system of equations. In numerical experiments, we compare these approaches in terms of accuracy and computational cost.

Identification (information)Computer scienceNumerical analysisApplied mathematicsSystem of linear equationsOptimal control
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Optimality Conditions for Non-Qualified Parabolic Control Problems

1994

We consider parabolic state constrained optimal control problems where the usual Slater condition is not necessarily satisfied. Instead, a weaker interiority property is assumed. Optimality conditions with a Lagrange multiplier are given. As an application we present an augmented Lagrangian algorithm. Numerical test results are included.

0209 industrial biotechnologyAugmented Lagrangian method010102 general mathematicsMathematicsofComputing_NUMERICALANALYSIS02 engineering and technologyState (functional analysis)Slater's conditionOptimal control01 natural sciencessymbols.namesake020901 industrial engineering & automationLagrange multipliersymbolsApplied mathematicsNumerical tests0101 mathematicsControl (linguistics)Mathematics
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Nonsmooth Penalty Techniques in Control of the Continuous Casting Process

1991

We introduce a mathematical model which is used to simulate the continuous casting process and to control the secondary cooling water sprays. The main object is to minimize the defects in the final products. The problem is formulated as an optimal control problem where the cost function is constructed according to certain metallurgical criteria and constraints. The temperature distribution of the strand is calculated by solving a nonlinear heat equation with free boundaries between solid and liquid phases.

Continuous castingNonlinear heat equationMathematical optimizationDistribution (mathematics)Control (management)Process (computing)Water coolingFunction (mathematics)Optimal controlMathematics
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On the Real-Time Simulation and Control of the Continuous Casting Process

1990

Ll this paper we present a method for controlling in real-time the secondary cooling of the continuous casting machine. The method is based on the heat transfer model, which simulates the temperature distribution of the cast, and on the use of direct digital control (DDC). Off-line simulation results considering the control method is presented.

Continuous castingComputer scienceReal-time simulationControl (management)Process (computing)Heat transfer modelDirect digital controlSimulationControl methods
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Real-time simulation and control system for the continuous casting process

2005

In this paper we present a real-time system which is used to simulate the unsteady-state continuous casting process and to control the secondary cooling water sprays. The aim of the control system is to keep the surface temperature of the slab constant with respect to time in spite of casting speed variations, and in this way minimize the formation of cracks in the final product. The simulator calculates the temperature distribution using a mathematical model based on a heat conduction formula with phase changes. The optimal spray water flow rates for each spray cooling zone will be calculated by minimizing the deviation between the target surface temperature and the calculated actual surfa…

Continuous castingMaterials scienceReal-time simulationWater flowCasting (metalworking)Control systemSlabWater coolingMechanicsThermal conduction
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