Albert A. Groenwold

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A number of recently proposed variants of the particle swarm optimization algorithm (PSOA) are applied to an extended Dixon-Szegö bound constrained test set in global optimization. Of the variants considered, it is shown that constriction as proposed by Clerc, and dynamic inertia and maximum velocity reduction as proposed by Fourie and Groenwold, represent(More)
Daniel N. Wilke Department of Mechanical and Aeronautical Engineering University of Pretoria Pretoria, 0002, South Africa wilkedn@tuks.co.za Schalk Kok Department of Mechanical and Aeronautical Engineering University of Pretoria Pretoria, 0002, South Africa schalk.kok@up.ac.za Albert A. Groenwold Department of Mechanical Engineering University of(More)
We reflect on the convergence and termination of optimization algorithms based on convex and separable approximations using two recently proposed strategies, namely a trust region with filtered acceptance of the iterates, and conservatism. We then propose a new strategy for convergence and termination, denoted f iltered conservatism, in which the acceptance(More)
We examine the rotational (in)variance of the continuous-parameter genetic algorithm (CPGA). We show that a standard CPGA, using blend crossover and standard mutation, is rotationally variant. To construct a rotationally invariant CPGA it is possible to modify the crossover operation to be rotationally invariant. This however results in a loss of diversity.(More)
1. Abstract We present an incomplete series expansion (ISE) as a basis for function approximation. The ISE is expressed in terms of an approximate Hessian matrix which may contain second, third and even higher order ‘main’ or diagonal terms, but which excludes ‘interaction’ or off-diagonal terms. From the ISE, a family of approximate interpolating functions(More)
1. Abstract There are several optical applications in which a mirror or lens requires accurate manipulation, for example in microscanning or focusing optical systems. Typically, such devices are designed on a trial-and-error basis. To improve on this procedure, we apply topology optimization in the design of a piezoelectric micropositioner. The mechanism(More)