Technical University of Berlin

About: Technical University of Berlin is a education organization based out in Berlin, Germany. It is known for research contribution in the topics: Laser & Catalysis. The organization has 27292 authors who have published 59342 publications receiving 1414623 citations. The organization is also known as: Technische Universität Berlin & TU Berlin.

A Discrete Laplace–Beltrami Operator for Simplicial Surfaces

Abstract: We define a discrete Laplace–Beltrami operator for simplicial surfaces (Definition 16). It depends only on the intrinsic geometry of the surface and its edge weights are positive. Our Laplace operator is similar to the well known finite-elements Laplacian (the so called “cotan formula”) except that it is based on the intrinsic Delaunay triangulation of the simplicial surface. This leads to new definitions of discrete harmonic functions, discrete mean curvature, and discrete minimal surfaces. The definition of the discrete Laplace–Beltrami operator depends on the existence and uniqueness of Delaunay tessellations in piecewise flat surfaces. While the existence is known, we prove the uniqueness. Using Rippa’s Theorem we show that, as claimed, Musin’s harmonic index provides an optimality criterion for Delaunay triangulations, and this can be used to prove that the edge flipping algorithm terminates also in the setting of piecewise flat surfaces.

Disjoining pressure in thin liquid foam and emulsion films—new concepts and perspectives

Abstract: The present review is a topical survey of the disjoining pressure in thin liquid foam and emulsion films from both the experimental and the theoretical points of view. Section 2 deals with the latest research work on experimental techniques with which the disjoining pressure Π in foam, emulsion, and pseudo-emulsion films can be measured. Although a lot of techniques are available, the question of the origin of the charges at the water/air and the water/oil interfaces of films, which are stabilized by non-ionic surfactants, has not yet been answered. We address this question in section 3, reviewing the latest relevant literature. The relevance of structural forces for the disjoining pressure is outlined in section 4, which focuses on films which are stabilized by surfactant/polyelectrolyte mixtures.

Explaining Recurrent Neural Network Predictions in Sentiment Analysis

Abstract: Recently, a technique called Layer-wise Relevance Propagation (LRP) was shown to deliver insightful explanations in the form of input space relevances for understanding feed-forward neural network classification decisions. In the present work, we extend the usage of LRP to recurrent neural networks. We propose a specific propagation rule applicable to multiplicative connections as they arise in recurrent network architectures such as LSTMs and GRUs. We apply our technique to a word-based bi-directional LSTM model on a five-class sentiment prediction task, and evaluate the resulting LRP relevances both qualitatively and quantitatively, obtaining better results than a gradient-based related method which was used in previous work.

The INTERSPEECH 2012 Speaker Trait Challenge

Abstract: Keywords: Computational Paralinguistics ; Speaker Traits ; Personality ; Likability ; Pathology Reference EPFL-CONF-174360 Record created on 2012-01-23, modified on 2017-05-10

Short Pulse X-Ray Laser at 32.6 nm Based on Transient Gain in Ne-like Titanium

Abstract: A novel two-step excitation scheme for an efficient table-top x-ray laser has been realized for the first time. A nanosecond pulse creates a plasma of neonlike ions of titanium, followed by a subpicosecond pulse which excites a nonstationary population inversion. With only a few joules of pump energy, a compact x-ray laser at 32.6 nm with a very high gain coefficient of $g\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}19{\mathrm{cm}}^{\ensuremath{-}1}$ and a gain-length product of $gL\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}9.5$ was achieved.