Show filters Hide filters

Refine your search

Publication Year
1-9 out of 9 results
Change view
  • Sort by:
47:23 Weierstraß-Institut für Angewandte Analysis und Stochastik (WIAS), Technische Informationsbibliothek (TIB) German 2017

"Extreme Fluids" - Some Examples, Challenges and Simulation Techniques for Flow Problems with Complex Rheology

In this talk we discuss numerical simulation techniques for incompressible fluids with complex rheology which means that local flow characteristics may differ significantly by several orders of magnitude, for instance due to non-isothermal behavior and pressure, resp., shear dependent viscosity. Such fluids usually include viscoplastic as well as viscoelastic effects which is typical for yield-stress fluids, granular material as well as polymer melts and kautschuk. Corresponding applications are relevant for polymer processing, but include also viscoplastic lubrication, fracking and macro encapsulation. In this talk, we present special discretization and solver techniques in which case the coupling between the velocity, pressure and additional variables for the stresses, which leads to restrictions for the choice of the FEM approximation spaces, and the (often) hyperbolic nature of the problem are handled with special Finite Element techniques including stabilization methods. The resulting linearized systems inside of outer Newton-like solvers are (special) nonsymmetric saddle point problems which are solved via geometrical multigrid approaches. We illustrate and analyze numerically the presented methodology for well-known benchmark configurations as well as protoypical industrial applications for several nonlinear flow models.
  • Published: 2017
  • Publisher: Weierstraß-Institut für Angewandte Analysis und Stochastik (WIAS), Technische Informationsbibliothek (TIB)
  • Language: German
52:42 Weierstraß-Institut für Angewandte Analysis und Stochastik (WIAS), Technische Informationsbibliothek (TIB) English 2017

Machine learning and applications

Since a few years Machine Learning (ML) has broadened the modeling toolbox for the sciences and industry. The talk will first remind the audience of the main ingredients for applying machine learning. Then various ML applications in the sciences namely Brain Computer Interfaces and Quantum Chemistry will be discussed.
  • Published: 2017
  • Publisher: Weierstraß-Institut für Angewandte Analysis und Stochastik (WIAS), Technische Informationsbibliothek (TIB)
  • Language: English
27:38 Weierstraß-Institut für Angewandte Analysis und Stochastik (WIAS), Technische Informationsbibliothek (TIB) German 2017

Lost in the Web?

To get information of mathematical software is sometimes like finding a needle in a haystack. But otherwise, more and more research results will be achieved by using mathematical software. Comprehensive and precise information about software used is also an important condition for the credibility of research results. But software has some unique features which pose new requirements to information infrastructure, especially the dynamic character of software, its encoding in formal languages, dependencies from hardware, other software, and further context information. The information on mathematical software is widely distributed on Web sites, repositories, portals, Web archives, etc., and is not standardized. The talk will address two relevant activities which can significantly improve the information about mathematical software: the initiatives for a citation standard for software, and the development of a comprehensive portal for mathematical software which integrates the existing information about software from the Web. A state of the art report on the swMATH service will illustrate the concepts and approaches.
  • Published: 2017
  • Publisher: Weierstraß-Institut für Angewandte Analysis und Stochastik (WIAS), Technische Informationsbibliothek (TIB)
  • Language: German
24:33 Weierstraß-Institut für Angewandte Analysis und Stochastik (WIAS), Technische Informationsbibliothek (TIB) German 2017

Make the most of your audio-visual simulation data

Visualisations of mathematical simulations play an important role in the communication of research results. However, in most cases simulation data is shown in publications either as snapshots or as supplemental videos. Either way, the full potential of visualized simulations is not exploited. This talk will show how the TIB AV-Portal supports researchers to uncover the hidden potential of visualisations such as simulations and animations and how this can help to increase the impact of their publications.
  • Published: 2017
  • Publisher: Weierstraß-Institut für Angewandte Analysis und Stochastik (WIAS), Technische Informationsbibliothek (TIB)
  • Language: German
25:49 Weierstraß-Institut für Angewandte Analysis und Stochastik (WIAS), Technische Informationsbibliothek (TIB) German 2017

Syncretism Distribution Modeling

The morphological analysis of paradigms (morpheme tables) generally proposes a distinction between accidental homophony (to and two represent different concepts, but sound the same) and systematic homophony (you (vs German singular du and plural ihr ) corresponds to the concept `2nd Person'). No specific assumptions are usually made about the distribution of accidental homophony, though. Therefore current assumptions cannot proof satisfactorily what should be regarded as systematic in morphology. We propose that accidental homophony should be assumed to be a random event in the statistical sense with a constant probability across languages and across paradigms. This approach allows us to assign a likelihood to any actual typological distribution of syncretism given a morphological analysis. And by computing such likelihoods for a range of analyses, we can then apply maximum likelihood analysis to determine the best analyses. Hence, the statistical foundation allow us to empirically test morphological analyses that include accidental syncretism. In this paper, we primarily introduce the conceptual and mathematical foundations of a statistical modeling technique, Syncretism Distribution Modeling, and show how it overcomes the problem of accidental homophony. In addition, we apply the technique to show that person paradigms must involve both accidental homophony and systematic syncretism.
  • Published: 2017
  • Publisher: Weierstraß-Institut für Angewandte Analysis und Stochastik (WIAS), Technische Informationsbibliothek (TIB)
  • Language: German
14:59 Weierstraß-Institut für Angewandte Analysis und Stochastik (WIAS), Technische Informationsbibliothek (TIB) German 2017

Consistent 3D turbulence parametrization in circulation models

We present an extension of the Dynamic Smagorinsky model (DSM) to parameterize the subgrid-scale momentum diffusion in global circulation models (GCM) In contrast to the standard approach, the test filter to determine the Smagorinsky parameter is separated from the resolution scale to exclude potential interactions. In addition, in GCMs the horizontal and vertical scales are usually treated differently due to gravity. While for the turbulent vertical diffusion of horizontal momentum a classical Smagorinsky approach is common, the respective horizontal diffusion in the free atmosphere is usually neglected. We show how to formulate the generalized DSM as subgrid-scale horizontal momentum diffusion to run stably a GCM without hyperdiffusion. Furthermore, the idea of stratified turbulence is applied to find a dynamic approach also for the vertical diffusion. Both improvements allow for a realistic spectrum of kinetic energy (almost) up to the resolution scale.
  • Published: 2017
  • Publisher: Weierstraß-Institut für Angewandte Analysis und Stochastik (WIAS), Technische Informationsbibliothek (TIB)
  • Language: German
26:33 Weierstraß-Institut für Angewandte Analysis und Stochastik (WIAS), Technische Informationsbibliothek (TIB) German 2017

Long-Term Accessibility of Software through Web Archives

Software is widely used and referenced in research and scientific publications. Hence, just like the results published in an article, associated software should be preserved and made long-term accessibly as well. Due to the nature of software and its dynamic aspects, this is rather challenging though. Very commonly, only related materials, such as a software's documentation, parts of its source code or change logs, are freely available. However, these can be very valuable to comprehend or reproduce experiments described in literature. We found that a big portion of this data is provided on the Web. Around 60% of the software webpages we analyzed link to documentation, while another 50% even contain some artifacts of the actual software [1, 2]. Web Archives are a way to preserve this information and allow for long-term accessibility, even if the software and corresponding information change. Although many of those websites are already archived, our study shows that the evolution of a software is not always well captured. Therefore, we are working towards a pro-active approach to archive software on the Web in the future as part of the scientific process. [1] Holzmann, H., Runnwerth, M., Sperber, W.: Linking Mathematical Software in Web Archives. 5th International Congress on Mathematical Software, ICMS 2016. Berlin, Germany (2016). [2] Holzmann, H., Sperber, W., Runnwerth, M.:?Archiving Software Surrogates on the Web for Future Reference.20th International Conference on Theory and Practice of Digital Libraries, TPDL 2016, Hannover, Germany(2016).
  • Published: 2017
  • Publisher: Weierstraß-Institut für Angewandte Analysis und Stochastik (WIAS), Technische Informationsbibliothek (TIB)
  • Language: German
14:56 Weierstraß-Institut für Angewandte Analysis und Stochastik (WIAS), Technische Informationsbibliothek (TIB) German 2017

Split-explicit methods for low Mach number flows with cut cell discretization

Split-explicit methods are a common integration method in numerical weather prediction. They combine two explicit methods to integrate different parts of the right hand side with different time steps. Common combinations are for the slow part Leap-Frog, Runge-Kutta, or Adams-method and for the fast part a Verlet-type integration method. For Runge-Kutta methods as the slow integrator Wensch et.al give a generalization (MIS-method) and analysed this new method in case of an exact integration of the fast part. When the orography is represented by a cut cell approach the splitting has to respect also the small cell problem. Modifications are described, which represent the fast part by a local linear operator and use a special implicit-explicit method for the integration of this linear differential equation. We will compare our new integrators and known methods for the two-dimensional compressible Euler-equations for examples with different Mach-numbers and grid configurations.
  • Published: 2017
  • Publisher: Weierstraß-Institut für Angewandte Analysis und Stochastik (WIAS), Technische Informationsbibliothek (TIB)
  • Language: German
23:27 Weierstraß-Institut für Angewandte Analysis und Stochastik (WIAS), Technische Informationsbibliothek (TIB) German 2017

zbMATH beyond publications

Today, mathematical research information extends far beyond the classical publication format. This is especially true in the area of modelling and simulation, where the theoretical aspects of modelling are naturally connected with research data, mathematical software, and computational results. While all these components are essential in the process of research, they are not always similarly reflected in the publications. We describe how zbMATH currently supports the needs for documentation, information, and reputation management of research beyond texts. We also outline some approaches for future developments.
  • Published: 2017
  • Publisher: Weierstraß-Institut für Angewandte Analysis und Stochastik (WIAS), Technische Informationsbibliothek (TIB)
  • Language: German
out of 1 pages
Loading...
Feedback

Timings

   98 ms - page object
   72 ms - search
    4 ms - highlighting
    1 ms - highlighting/21901
    1 ms - highlighting/21906
    0 ms - highlighting/21914
    0 ms - highlighting/21915
    1 ms - highlighting/21907
    2 ms - highlighting/21903
    1 ms - highlighting/21905
    1 ms - highlighting/21904
    1 ms - highlighting/21918

Version

AV-Portal 3.8.0 (dec2fe8b0ce2e718d55d6f23ab68f0b2424a1f3f)