Comparison of Different FE-Approaches for Modelling of Short Fibre Composites

In this article, four different FEM based methods for modelling of unidirectional short fibre composites are evaluated. The four methods differ in how they assign material properties. Method 1 and 2 assign them to whole elements while method 3 and 4 assign them to quadrature points. All four methods have in common that they use a structured mesh that does not resolve the microstructural geometry. This approach is in contrast to traditional methods in which the microstructure is mapped by a geometry-bound mesh, an approach that leads to work-intensive meshing and very small elements and thus high computational costs. The overall aim of all four methods is to reduce the computational costs caused by traditional meshing. The methods are evaluated with respect to their convergence behaviour and the obtained homogenised material properties. It is worked out that two of the four methods are well suited for modelling of complex microstructures

Historical perspectives and contemporary challenges to education (Bildung) and citizenry in the modern nation state. Comparative perspectives on Germany and the USA

In this article, we provide a comparative analysis of public education in Germany and the US, focusing on historical and contemporary challenges to education, Bildung, and citizenry in the modern nation state. In particular, we examine relations among nation building processes and education, transnational discourses, mutual influences, and relations regarding public education over time, and identity building and citizenship within and between federal, nation state and international levels. Comparative methods are utilized to examine policy documents as well as the literature, looking for similarities and differences among key concepts and discourses. The article concludes by pointing out that a number of contemporary developments bringing public education to a crossroads today are not entirely new and that foundations of education theory are still relevant. At the same time, we suggest new cross-national dialogues regarding the challenges bringing public education to the crossroads today. (DIPF/Orig.

A natural prior probability distribution derived from the propositional calculus

AbstractA σ-additive probability measure on the real interval [0, 1] is defined by considering the expected values of “randomly chosen” large formulae of the propositional calculus, where the propositional variables are treated as independent random variables on {0, 1} with expected value 12. Although arising naturally from logical and/or cognitive considerations, this measure is extremely complex and displays certain formally pathological features, including infinite density at all points of a certain dense subset of [0, 1]. Certain variantsof the construction are also considered. The introduction includes an account of motivation for the study of such measures arising from a fundamental problem in inexact reasoning

DELIBERATION, JUDGEMENT AND THE NATURE OF EVIDENCE

A normative Bayesian theory of deliberation and judgement requires a procedure for merging the evidence of a collection of agents. In order to provide such a procedure, one needs to ask what the evidence is that grounds Bayesian probabilities. After finding fault with several views on the nature of evidence (the views that evidence is knowledge; that evidence is whatever is fully believed; that evidence is observationally set credence; that evidence is information), it is argued that evidence is whatever is rationally taken for granted. This view is shown to have consequences for an account of merging evidence, and it is argued that standard axioms for merging need to be altered somewhat

LoCoH: nonparameteric kernel methods for constructing home ranges and utilization distributions.

Parametric kernel methods currently dominate the literature regarding the construction of animal home ranges (HRs) and utilization distributions (UDs). These methods frequently fail to capture the kinds of hard boundaries common to many natural systems. Recently a local convex hull (LoCoH) nonparametric kernel method, which generalizes the minimum convex polygon (MCP) method, was shown to be more appropriate than parametric kernel methods for constructing HRs and UDs, because of its ability to identify hard boundaries (e.g., rivers, cliff edges) and convergence to the true distribution as sample size increases. Here we extend the LoCoH in two ways: "fixed sphere-of-influence," or r-LoCoH (kernels constructed from all points within a fixed radius r of each reference point), and an "adaptive sphere-of-influence," or a-LoCoH (kernels constructed from all points within a radius a such that the distances of all points within the radius to the reference point sum to a value less than or equal to a), and compare them to the original "fixed-number-of-points," or k-LoCoH (all kernels constructed from k-1 nearest neighbors of root points). We also compare these nonparametric LoCoH to parametric kernel methods using manufactured data and data collected from GPS collars on African buffalo in the Kruger National Park, South Africa. Our results demonstrate that LoCoH methods are superior to parametric kernel methods in estimating areas used by animals, excluding unused areas (holes) and, generally, in constructing UDs and HRs arising from the movement of animals influenced by hard boundaries and irregular structures (e.g., rocky outcrops). We also demonstrate that a-LoCoH is generally superior to k- and r-LoCoH (with software for all three methods available at http://locoh.cnr.berkeley.edu)

Evolving eco-system: a network of networks

Ecology and evolution are inseparable. Motivated by some recent experiments, we have developed models of evolutionary ecology from the perspective of dynamic networks. In these models, in addition to the intra-node dynamics, which corresponds to an individual-based population dynamics of species, the entire network itself changes slowly with time to capture evolutionary processes. After a brief summary of our recent published works on these network models of eco-systems, we extend the most recent version of the model incorporating predators that wander into neighbouring spatial patches for food.Comment: 7 pages including 2 figure