Parametric Model Order Reduction of Port-Hamiltonian Systems by Matrix Interpolation

In this paper, parametric model order reduction of linear time-invariant systems by matrix interpolation is adapted to large-scale systems in port-Hamiltonian form. A new weighted matrix interpolation of locally reduced models is introduced in order to preserve the port-Hamiltonian structure, which guarantees the passivity and stability of the interpolated system. The performance of the new method is demonstrated by technical example

Parametric model order reduction of port-hamiltonian systems by matrix interpolation

ISSN:0178-2312ISSN:2196-677

Functional relationship between cognitive representations of movement directions and visuomotor adaptation performance

Lex H, Weigelt M, Knoblauch A, Schack T. Functional relationship between cognitive representations of movement directions and visuomotor adaptation performance. Experimental Brain Research. 2012;223(4):457-467.The aim of our study was to explore whether or not different types of learners in a sensorimotor task possess characteristically different cognitive representations. Participants' sensorimotor adaptation performance was measured with a pointing paradigm which used a distortion of the visual feedback in terms of a left-right reversal. The structure of cognitive representations was assessed using a newly established experimental method, the Cognitive Measurement of Represented Directions. A post hoc analysis revealed inter-individual differences in participants' adaptation performance, and three different skill levels (skilled, average, and poor adapters) have been defined. These differences in performance were correlated with the structure of participants' cognitive representations of movement directions. Analysis of these cognitive representations revealed performance advantages for participants possessing a global cognitive representation of movement directions (aligned to cardinal movement axes), rather than a local representation (aligned to each neighboring direction). Our findings are evidence that cognitive representation structures play a functional role in adaptation performance