@inproceedings{17024, author = {{Day, Sarah and Junge, Oliver and Mischaikow, Konstantin}}, booktitle = {{Proceedings of Equadiff 2003, International Conference on Differential Equations}}, isbn = {{9789812702067}}, title = {{{Towards automized chaos verification}}}, doi = {{10.1142/9789812702067_0014}}, year = {{2005}}, } @inproceedings{17112, author = {{Bienkowski, Marcin and Damerow, Valentina and Meyer auf der Heide, Friedhelm and Sohler, Christian}}, booktitle = {{Proceedings of the 21st European Workshop on Computational Geometry, Eindhoven, The Netherlands, March 9-11, 2005}}, publisher = {{Technische Universiteit Eindhoven}}, title = {{{Average case complexity of Voronoi diagrams of n sites from the unit cube}}}, year = {{2005}}, } @proceedings{17113, editor = {{Leonardi, Stefano and Meyer auf der Heide, Friedhelm and Wagner, Dorothea}}, location = {{Schloss Dagstuhl, Germany}}, title = {{{Abstracts Collection -- Algorithmic Aspects of Large and Complex Networks}}}, volume = {{05361}}, year = {{2005}}, } @inproceedings{11803, abstract = {{In this paper we propose a novel adaptation algorithm for Filter-and-Sum beamforming in spatially correlated noise. Deterministic and stochastic gradient ascent algorithms are derived from a constrained optimization problem, which iteratively estimate the principal eigenvecto r of a generalized eigenvalue problem. The method does not require an explicit estimation of the speaker location. It is shown that the well-known Delay-and-Sum beamformer and the previously introduced Filter-and-Sum beamformer in spatially white noise are obtained as special cases. Further, bounds on the maximally achievable SNR gains are derived and it is shown that the proposed adaptation algorithm is able to approach these performance bounds.}}, author = {{Haeb-Umbach, Reinhold and Warsitz, Ernst}}, booktitle = {{International Workshop on Acoustic Echo and Noise Control (IWAENC 2005)}}, title = {{{Adaptive Filter-and-Sum Beamforming in Spatially Correlated Noise}}}, year = {{2005}}, } @inproceedings{11827, abstract = {{The transmission errors in a wireless or packet oriented network may dramatically decrease the performance of a distributed speech recognition DSR) system. Error concealment has been shown to be an effective way to mantain an acceptable word error rate when dealing with error prone communication channels. In this paper we propose an extension of our previously introduced soft features approach for the case that the soft-output of the channel decoder is not available at the server side of the DSR system. We found a simple method to estimate bit reliability information which still gives good speech recognition results. It is shown that some other error concealment schemes turn out to be special cases of the method proposed here.}}, author = {{Ion, Valentin and Haeb-Umbach, Reinhold}}, booktitle = {{Interspeech 2005}}, title = {{{A Unified Probabilistic Approach to Error Concealment for Distributed Speech Recognition}}}, year = {{2005}}, } @inproceedings{11828, abstract = {{In this paper we present a comparison of the recently proposed Soft-Feature Distributed Speech Recognition (SFDSR) with the two evaluated candidate codecs for Speech Enabled Services over wireless networks: Adaptive Multirate Codec (AMR) and the ETSI Extended Advanced Front-End for Distributed Speech Recognition (XAFE). It is shown that SFDSR achieves the best recognition performance on a simulated GSM transmission, followed by XAFE and AMR.We also present some new results concerning SFDSR which demonstrate the versatility of the approach. Further, a simple method is introduced which considerably reduces the computational effort.}}, author = {{Ion, Valentin and Haeb-Umbach, Reinhold}}, booktitle = {{IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2005)}}, keywords = {{adaptive codes, adaptive multirate codec, AMR, distributed speech recognition, ETSI, extended advanced front-end, recognition performance, SFDSR, simulated GSM transmission, soft-feature distributed speech recognition, speech codecs, speech coding, speech recognition, variable rate codes, XAFE}}, pages = {{333--336}}, title = {{{A Comparison of Soft-Feature Distributed Speech Recognition with Candidate Codecs for Speech Enabled Mobile Services}}}, doi = {{10.1109/ICASSP.2005.1415118}}, volume = {{1}}, year = {{2005}}, } @inproceedings{11930, abstract = {{For human-machine interfaces in distant-talking environments multichannel signal processing is often employed to obtain an enhanced signal for subsequent processing. In this paper we propose a novel adaptation algorithm for a filter-and-sum beamformer to adjust the coefficients of FIR filters to changing acoustic room impulses, e.g. due to speaker movement. A deterministic and a stochastic gradient ascent algorithm are derived from a constrained optimization problem, which iteratively estimates the eigenvector corresponding to the largest eigenvalue of the cross power spectral density of the microphone signals. The method does not require an explicit estimation of the speaker location. The experimental results show fast adaptation and excellent robustness of the proposed algorithm.}}, author = {{Warsitz, Ernst and Haeb-Umbach, Reinhold}}, booktitle = {{IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 2005)}}, keywords = {{acoustic filter-and-sum beamforming, acoustic room impulses, acoustic signal processing, adaptive principal component analysis, adaptive signal processing, architectural acoustics, constrained optimization problem, cross power spectral density, deterministic algorithm, deterministic algorithms, distant-talking environments, eigenvalues and eigenfunctions, eigenvector, enhanced signal, filter-and-sum beamformer, FIR filter coefficients, FIR filter coefficients, FIR filters, gradient methods, human-machine interfaces, iterative estimation, iterative methods, largest eigenvalue, microphone signals, multichannel signal processing, optimisation, principal component analysis, spectral analysis, stochastic gradient ascent algorithm, stochastic processes}}, pages = {{iv/797--iv/800 Vol. 4}}, title = {{{Acoustic filter-and-sum beamforming by adaptive principal component analysis}}}, doi = {{10.1109/ICASSP.2005.1416129}}, volume = {{4}}, year = {{2005}}, } @misc{15352, abstract = {{Impulsbasierte Ultraschallsensorsysteme zur Messung von Füllstand, Durchfluss und Konzentration sind heutzutage aufgrund ihrer Robustheit und Wartungsfreundlichkeit weit verbreitet. Probleme treten immer dann auf, wenn sich Gasblasen im Medium befinden. Diese verändern das empfangene Signal derart, dass eine exakte Messung der Schallgeschwindigkeit des flüssigen Mediums nicht mehr möglich ist. Dieser Beitrag behandelt eine neue Art der Signalauswertung, die eine zuverlässige Bestimmung der Schallgeschwindigkeit auch in diesem Fall gewährleistet. Darüber hinaus können auch Rückschlüsse auf den Gasanteil innerhalb des flüssigen Mediums gewonnen werden.}}, author = {{Gulsch, Michael and Henning, Bernd}}, title = {{{Bestimmung des Anteils ungelöster Gase in flüssigen Medien}}}, year = {{2005}}, } @inproceedings{15353, abstract = {{Currently there are pulse based ultrasonic sensor systems used to measure flow, liquid level, concentration or in process monitoring. In several processes the investigated media are a mixture of liquid and solid ingredients (emulsions, suspensions). The use of ultrasonic sensor systems will be very complicated if gas bubbles appear at the measurement place caused by chemical reactions, high temperature or fast flow that means by typical process conditions. Firstly, the appearance of gas bubbles falsifies the measured absorption. Secondly, the measured velocity is influenced by gas bubbles. In figure 1 is visible that a volume fraction of 0.1 ppm of undissolved air decreases the sound velocity by 1.4 m s-1}}, author = {{Gulsch, Michael and Henning, Bernd}}, booktitle = {{2005 IEEE Ultrasonics Symposium}}, pages = {{780--782}}, title = {{{Bubble detection and gas volume measurement in bubble loaded liquids with pulse driven measurement devices}}}, year = {{2005}}, } @inproceedings{15354, abstract = {{In vielen verfahrenstechnischen Prozessen ist die kontinuierliche Regelung von Prozessgrößen für einen stabilen und sicheren Betrieb eine wichtige Vorraussetzung. Die Erfassung der Zielgrößen geschieht aufgrund von hoher Robustheit und Wartungsfreundlichkeit zunehmend mit akustischen Messverfahren. Besonders impulsbasierte Messsysteme werden häufig zur Messung von Durchfluss, Füllstand und in der Flüssigkeitsanalytik auch zur Konzentrationsmessung benutzt. Dabei führen am Messort auftretende Gasblasen zu großen messtechnischen Problemen. Sie verändern die gemessenen akustischen Stoffkenngrößen, wodurch es zur fehlerhaften Regelung bestimmter Prozesszielgrößen kommt.}}, author = {{Gulsch, Michael and Henning, Bernd}}, booktitle = {{Fortschritte der Akustik - DAGA '05}}, editor = {{Fastl, Hugo and Fruhmann, Markus}}, isbn = {{3-9808659-1-6}}, pages = {{587--588}}, publisher = {{Deutsche Gesellsch. f. Akustik}}, title = {{{Gasvolumenmessung in blasenbeladenen Flüssigkeiten}}}, year = {{2005}}, } @inproceedings{15355, abstract = {{Today headlights are built with transparent polycarbonate front windows. If the air moisture inside the headlight is high and the outside temperature decreases below the dew-point, the air moisture condensates inside and the inner surface of the polycarbonate front window (PCFW) becomes nontransparent (figure 1). To the costumer this appears as an optical defect.In order to avoid the condensation and to speed up the evaporation of the condensed water (condensate) on the PCFW a Computational-Fluid-Dynamic-simulation is used. The simulation results are proceeded to optimise the airflow and the arrangement of the breather holes. An important problem is the validation of the simulated results with the reality. It was necessary to build a non-invasive measurement system for the continuous characterisation of condensated areas without affecting the material properties, the airflow and the light distribution inside the headlight.}}, author = {{Gulsch, Michael and Unverzagt, Carsten and Henning, Bernd and Nolte, Sascha}}, location = {{Nürnberg}}, pages = {{455--460}}, title = {{{Visualisation and Measurement of Condensed Water in Automobile Headlights}}}, year = {{2005}}, } @article{15356, author = {{Handel, Peter and Tournier, Adam and Henning, Bernd}}, journal = {{IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control}}, number = {{9}}, pages = {{1461--1467}}, title = {{{Quantum 1/f Effect in Resonant Biochemical Piezoelectric and MEMS Sensors}}}, volume = {{52}}, year = {{2005}}, } @inproceedings{15358, abstract = {{In the 1950's many investigations have been made in measuring the Young's and the shear modus of isotropic materials with acoustic waves. Therefore both the longitudinal and transversal sound velocities have been determined with only one specimen, that had to be large in comparison to the wavelength (Brown, Reynolds, Dunegan). Therewith the method was suited only for low absorbing materials. In the 1990's further developments led to mono mode rods to describe viscoelastic properties. Their diameters had to be very small for high frequencies, thus giving practical values up to 65 kHz (Benatar). This contribution is about a tubular multi mode specimen and its application for the simultaneous measurement of the abovementioned acoustic properties at high frequencies.}}, author = {{Rautenberg, Jens and Henning, Bernd}}, location = {{Beijing, China}}, title = {{{Acoustic properties of highly attenuating isotropic media}}}, year = {{2005}}, } @inproceedings{15359, abstract = {{In den bekannten grundlegenden Ausf¨uhrungen zur Erzeugung hörbaren Schalls durch Eigendemodulation amplitudenmodulierten Leistungsultraschalls (siehe u.a. Westervelt, Berktay) wird von zwei räumlich übereinander liegenden Wellen unterschiedlicher Frequenz im nichtlinearen Medium ausgegangen, so dass neben ihren Harmonischen auch Summen- und Differenzfrequenzen entstehen. Die perfekte räumliche Ueberdeckung der Wellen im Freifeld kann mit herkömmlichen Schallwandlern allerdings nur unzul¨anglich erreicht werden. Trotzdem sind in der Vergangenheit einige so genannte parametrische Lautsprecher entwickelt worden. Um annähernd die erwähnten Voraussetzungen zu gewährleisten, sind gängige Systeme mit einem Durchmesser von ca. 30 cm relativ groß. Dies soll auch dem angestrebten Sekundärschalldruck Rechnung tragen, der linear mit der effektiv abstrahlenden Fl¨ache wächst. Zum Aufbau dieser großen Flächen werden teilweise viele kleine Ultraschallwandler zu einem Array zusammengesetzt. Der hohe Preis einzelner Wandler aber auch die notwendige Sortierung beispielsweise bezüglich ihrer Mittenfrequenz macht den Aufbau solcher Systeme aufwändig. Erst am vollständig aufgebauten Array werden schließlich Frequenzgang und Richtcharakteristik des Sekundärschalls ermittelt. Im Sinne kürzerer Entwicklungszeiten und -kosten wäre es wünschenswert, bereits vor dem Aufbau des Arrays allein durch Untersuchung des einzelnen Ultraschallwandlers eine Prognose über die zu erwartenden Eigenschaften des Gesamtsystems vornehmen zu können. In diesem Beitrag wird ein Versuchsaufbau vorgestellt, der unter strenger Beachtung der anfangs erwähnten Voraussetzungen die parametrische Schallerzeugung mit nur einem Ultraschallwandler kleiner Baugröße erlaubt. Die Frequenzg änge des Sekundärschalls von Einzelelement und Array werden bei entsprechender Distanz gegen¨ubergestellt. Vorzüge des neuen Messaufbaus, beispielsweise die Möglichkeit zur Variation von Druck, Temperatur oder Luftfeuchtigkeit, um atmosphärische Einflüsse auf die parametrische Schallerzeugung zu untersuchen, werden skizziert}}, author = {{Rautenberg, Jens and Henning, Bernd}}, booktitle = {{Fortschritte der Akustik - DAGA '05}}, editor = {{Fastl, Hugo and Fruhmann, Markus}}, isbn = {{3-9808659-1-6}}, pages = {{491--492}}, publisher = {{Deutsche Gesellsch. f. Akustik}}, title = {{{Charakterisierung einzelner Ultraschallwandler für den Aufbau eines mehrelementigen parametrischen Lautsprechers}}}, year = {{2005}}, } @inproceedings{15360, abstract = {{One method to generate focused sound is to transmit amplitude modulated ultrasound of high energy in a nonlinear medium, so that sum and difference frequencies develop. Practically wide arrays of many small ultrasonic transducers are used, but the generation of very low frequencies is always weak. This contribution is about the experimental investigation of the {\textquotedbl}generation zone{\textquotedbl} -- that is the distance between the ultrasonic loudspeaker and the listener -- and the decrease of the lower frequency bound of the audible sound beam with distance. The main focus is on the experimental setup, which permits the parametric sound generation with only one ultrasonic transducer and a waveguide. In addition, the new measurement setup enables to show an additional effect: The de-coherence of the primary ultrasound wave which may be caused by saturation of air. This is why the lower frequency bound decreases as well if we approach the ultrasonic transducer.}}, author = {{Rautenberg, Jens and Henning, Bernd}}, location = {{Paderborn}}, title = {{{Lower Frequency Bound of Parametric Arrays}}}, year = {{2005}}, } @inproceedings{15700, author = {{Schulte, Carsten and Magenheim, Johannes}}, booktitle = {{ICER}}, pages = {{143--153}}, publisher = {{ACM}}, title = {{{Novices' expectations and prior knowledge of software development: results of a study with high school students}}}, year = {{2005}}, } @inproceedings{15701, author = {{Brinda, Torsten and Schulte, Carsten}}, booktitle = {{INFOS}}, pages = {{137--148}}, publisher = {{GI}}, title = {{{Beiträge der Objektorientierung zu einem Kompetenzmodell des informatischen Modellierens}}}, volume = {{{P-60}}}, year = {{2005}}, } @inproceedings{15702, author = {{Schulte, Carsten and Magenheim, Johannes}}, booktitle = {{INFOS}}, pages = {{111--122}}, publisher = {{GI}}, title = {{{Erwartungen und Wahlverhalten von Schülerinnen und Schülern gegenüber dem Schulfach Informatik - Ergebnisse einer Umfrage}}}, volume = {{P-60}}, year = {{2005}}, } @inproceedings{15799, author = {{Brinker, K. and Hüllermeier, Eyke}}, booktitle = {{In Proceedings of the NIPS-2005 Workshop on Learning to Rank, Whistler, BC, Canada}}, editor = {{Agarwal, S. and Cortes, C. and Herbrich, R.}}, pages = {{1--6}}, publisher = {{http://web.mit.edu/shivani/www/Ranking-NIPS-05/.}}, title = {{{Calibrated label-ranking}}}, year = {{2005}}, } @inproceedings{15800, author = {{Hüllermeier, Eyke and Fürnkranz, J. and Beringer, J.}}, booktitle = {{In Proceedings LWA/FGML-2005, German Workshop on Machine Learning, Saarbrücken, Germany }}, pages = {{158--163}}, title = {{{On position error and label ranking through iterated choice}}}, year = {{2005}}, }