102,118 research outputs found
Verlofstelsels in strafzaken. De toelaatbaarheid van het bezwaarvereiste, het verlofstelsel in hoger beroep en het selectiestelsel in cassatie onder de mensenrechten op beroep en een eerlijk proces
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182090.pdf (Publisher’s version ) (Open Access)Radboud University, 16 februari 2018Promotores : Kempen, P.H.P.H.M.C. van, Vegter, P.C.449 p
Equivariant singularity theory with distinguished parameters: Two case studies of resonant Hamiltonian systems
Get PDFWe consider Hamiltonian systems near equilibrium that can be (formally) reduced to one degree of freedom. Spatio-temporal symmetries play a key role. The planar reduction is studied by equivariant singularity theory with distinguished parameters. The method is illustrated on the conservative spring-pendulum system near resonance, where it leads to integrable approximations of the iso-energetic Poincaré map. The novelty of our approach is that we obtain information on the whole dynamics, regarding the (quasi-) periodic solutions, the global configuration of their invariant manifolds, and bifurcations of these.
Algorithms for computing normally hyperbolic invariant manifolds
Get PDFAn effcient algorithm is developed for the numerical computation of normally hyperbolic invariant manifolds, based on the graph transform and Newton's method. It fits in the perturbation theory of discrete dynamical systems and therefore allows application to the setting of continuation. A convergence proof is included. The scope of application is not restricted to hyperbolic attractors, but extends to normally hyperbolic manifolds of saddle type. It also computes stable and unstable manifolds. The method is robust and needs only little specification of the dynamics, which makes it applicable to e.g. Poincaré maps. Its performance is illustrated on examples in 2D and 3D, where a numerical discussion is included.
Certified meshing of Radial Basis Function based isosurfaces
Get PDFRadial Basis Functions are widely used in scattered data interpolation. The surface-reconstruction method using radial basis functions consists of two steps: (i) computing an interpolating implicit function the zero set of which contains the points in the data set, followed by (ii) extraction of isocurves or isosurfaces. In this paper we focus on the second step, generalizing the work on certified meshing of implicit surfaces based on interval arithmetic (Plantinga and Vegter in Visual Comput. 23:45-58, 2007). It turns out that interval arithmetic, and even the usually faster affine arithmetic, are far too slow in the context of RBF-based implicit surface meshing. We present optimized strategies giving acceptable running times and better space complexity, exploiting special properties of RBF-interpolants. We present pictures and timing results confirming the improved quality of these optimized strategies
Minimal Delaunay Triangulations of Hyperbolic Surfaces
Get PDFMotivated by recent work on Delaunay triangulations of hyperbolic surfaces, we consider the minimal number of vertices of such triangulations. First, we show that every hyperbolic surface of genus g has a simplicial Delaunay triangulation with O(g) vertices, where edges are given by distance paths. Then, we construct a class of hyperbolic surfaces for which the order of this bound is optimal. Finally, to give a general lower bound, we show that the Ω(√g) lower bound for the number of vertices of a simplicial triangulation of a topological surface of genus g is tight for hyperbolic surfaces as well
Resonances in a spring-pendulum: algorithms for equivariant singularity theory
Get PDFA spring-pendulum in resonance is a time-independent Hamiltonian model system for formal reduction to one degree of freedom, where some symmetry (reversibility) is maintained. The reduction is handled by equivariant singularity theory with a distinguished parameter, yielding an integrable approximation of the Poincaré map. This makes a concise description of certain bifurcations possible. The computation of reparametrizations from normal form to the actual system is performed by Gröbner basis techniques.
Bibliographie Hilarion G. Petzold 1958 – 2009 mit Anhang als Einführung
No full textDieses Archiv enthält die Gesamtbibliographie der Werke des Autors nebst einiger Texte „Über H. G. Petzold“ im Schlussteil der Bibliographie sowie einen Anhang mit einer Einführung in die Architektur des Werkes in seinem wissenslogischen Aufbau als Ausarbeitung seines „Tree of Science Modells“ (2007).This archive contains the complete bibliography of the author and some texts about H. G. Petzold, moreover an epilogue with an introduction to the architecture of the works in its epistemological structure and composition and as an elaborations of Petzold’s „Tree of Science Modell (2007).https://www.fpi-publikation.de/polyloge/01-2009-petzold-h-g-gesamtbibliographie-h-g-petzold-1958-2009-updating-november2009/peerReviewedpublishedVersio
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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