University of Paderborn

About: University of Paderborn is a education organization based out in Paderborn, Nordrhein-Westfalen, Germany. It is known for research contribution in the topics: Control reconfiguration & Software. The organization has 6684 authors who have published 16929 publications receiving 323154 citations.

Identification of Material Parameters for Constitutive Equations

Abstract: This contribution addresses various topics on parameter identification for constitutive equations on the basis of experimental data. Starting from basic characteristics of inverse problems illustrated by simple examples, four different identification methods are introduced. Then particular aspects of the least squares approach are outlined, such as optimization, local minima, sensitivity analysis, consequences of instabilities, and stochastic methods. Uniform small strain problems and nonuniform large strain problems are considered, where for the latter finite element results are incorporated into the optimization process. The examples are concerned with a perturbation technique in order to detect possible instabilities, a stochastic analysis in order to examine the uncertainty of parameter estimates, and a necking problem observed with an optical method in order to take into account nonuniform large strains during the experiment. Keywords: inverse problems; optimization; stochastic methods; plasticity; large strains

Crystal Growth from Solutions

Abstract: Gravity-related phenomena in crystal growth from solutions are reviewed in the first section of the paper. The second and third sections deal with solution growth experiments performed in space at high and low temperatures. The basis for conceiving these experiments is discussed and the experimental procedures, both for the space experiments and the reference experiments on the ground, are explained including the development of appropriate hardware. Analysis of the results obtained allows the identification of materials and techniques relevant for space conditions.

Teachers‘ attitudes and beliefs regarding ICT in teaching and learning in European countries:

Abstract: In the debate on the integration of information and communication technologies (ICT) into schools, the beliefs and attitudes of teachers towards ICT in teaching and learning have always been regard...

Theoretical Analysis of the k -Means Algorithm – A Survey

Abstract: The k-means algorithm is one of the most widely used clustering heuristics. Despite its simplicity, analyzing its running time and quality of approximation is surprisingly difficult and can lead to deep insights that can be used to improve the algorithm. In this paper we survey the recent results in this direction as well as several extension of the basic k-means method.