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Legal Notice. eco.mont (Journal on Protected Mountain Areas Research and Management)|eco.mont Vol. 13 special issue 2021|
No full textContent. eco.mont (Journal on Protected Mountain Areas Research and Management)|eco.mont Vol. 13 special issue 2021|
No full textStructure preservation for the Deep Neural Network Multigrid Solver. ETNA - Electronic Transactions on Numerical Analysis
No full textThe simulation of partial differential equations is a central subject of numerical analysis and an indispensable tool in science, engineering, and related fields. Existing approaches, such as finite elements, provide (highly) efficient tools but deep neural network-based techniques emerged in the last few years as an alternative with very promising results. We investigate the combination of both approaches for the approximation of the Navier-Stokes equations and to what extent structural properties such as divergence freedom can and should be respected. Our work is based on DNN-MG, a deep neural network multigrid technique, that we introduced recently and which uses a neural network to represent fine grid fluctuations not resolved by a geometric multigrid finite element solver. Although DNN-MG provides solutions with very good accuracy and is computationally highly efficient, we noticed that the neural network-based corrections substantially violate the divergence freedom of the velocity vector field. In this contribution, we discuss these findings and analyze three approaches to address the problem: a penalty term to encourage divergence freedom of the network output; a penalty term for the corrected velocity field; and a network that learns the stream function and which hence yields divergence-free corrections by construction. Our experimental results show that the third approach based on the stream function outperforms the other two and not only improves the divergence freedom but also the overall fidelity of the simulation
Union Instability as an Engine of Fertility? A Micro-simulation Model for France
No full textMicro-level relationships between union formation or dissolution and childbearing haveimplications for fertility that have not been thoroughly examined. In this paper, we suggestthat these relationships comprise an ‘engine’ that produces variation and change aroundreplacement level fertility. On the one hand, union dissolution reduces opportunities forconceiving and bearing children. At the same time, it produces a pool of persons who mayenter new partnerships and produce ‘extra’ children. The balance between these twoopposing forces and their implications for fertility levels is unknown and will depend inpart on the timing of union formation and parenthood. In this paper, we estimate theparameters of these micro-level relationships for female respondents to the 1999 French`Etude de l’Histoire Familiale´. We use those parameters to simulate the implications ofnon-union childbearing, union dissolution and re-partnering for completed family size. Wealso investigate the extent to which links between union formation or dissolution andchildbearing depend on the timing of unions and births
I. German phonotactic vs. morphonotactic obstruent clusters: a corpus linguistic analysis. Veröffentlichungen zur Linguistik und Kommunikationsforschung|Experimental, Acquisitional and Corpus linguistic Approaches to the Study of Morphonotactics Veröffentlichungen zur Linguistik und Kommunikationsforschung Band 33|
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Preliminaries. Orea|The Archaeology of the Arabian Peninsula 2 Oriental and European Archaeology Volume 19|
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Upper Hessenberg and Toeplitz Bohemian matrix sequences: a note on their asymptotical eigenvalues and singular values. ETNA - Electronic Transactions on Numerical Analysis
No full textIn previous works, Bohemian matrices have attracted the attention of several researchers for their rich combinatorial structure, and they have been studied intensively from several points of view, including height, determinants, characteristic polynomials, normality, and stability.Here we consider a selected number of examples of upper Hessenberg and Toeplitz Bohemian matrix sequences whose entries belong to the population , and we propose a connection with the spectral theory of Toeplitz matrix sequences and Generalized Locally Toeplitz (GLT) matrix sequences in order to giveresults on the localization and asymptotical distribution of their spectra and singular values. Numerical experiments that support the mathematical study are reported. A conclusion section ends the note in order to illustrate the applicability of the proposed tools to more general cases
