Adaptive back-propagation in on-line learning of multilayer networks

An adaptive back-propagation algorithm is studied and compared with gradient descent (standard back-propagation) for on-line learning in two-layer neural networks with an arbitrary number of hidden units. Within a statistical mechanics framework, both numerical studies and a rigorous analysis show that the adaptive back-propagation method results in faster training by breaking the symmetry between hidden units more efficiently and by providing faster convergence to optimal generalization than gradient descent.

On the annealed VC entropy for margin classifiers: A statistical mechanics study

Using techniques from Statistical Physics, the annealed VC entropy for hyperplanes in high dimensional spaces is calculated as a function of the margin for a spherical Gaussian distribution of inputs.

Error-correcting codes on a Bethe-like lattice

We analyse Gallager codes by employing a simple mean-field approximation that distorts the model geometry and preserves important interactions between sites. The method naturally recovers the probability propagation decoding algorithm as a minimization of a proper free-energy. We find a thermodynamical phase transition that coincides with information theoretical upper-bounds and explain the practical code performance in terms of the free-energy landscape.

Mit, gegen und nach Brecht:Heiner Müllers Fatzer

Heiner Müller has often been described as the only rightful (literary) heir and flag- bearer of Bertolt Brecht in German drama of the late twentieth century. This article first examines the critical position that Müller took towards his predecessor. The essay will then focus on the Fatzer complex which Müller considered to be by far the most important work by Brecht. Next, I will discuss the relationship between Fatzer and Müllerʼs synthesised stage version FATZER from 1978, followed by a brief assessment of the various ways in which Mu ̈ller treated Brechtʼs Fatzer material over the next two decades. Special attention will be paid to the radio play that Müller produced of his version of Fatzer during the final years of the GDR; I argue that it represents an exemplary engagement with Brecht’s fragment because, rather than aiming for a standard illusionistic radio play, Mu ̈ller’s intention is to allow his FATZER version, as it were, to speak for itself. To conclude, the essay undertakes a brief and inevitably speculative discussion of the influence of Brechtʼs unfinished drama project on Müller’s works.