1,721,116 research outputs found
Riemann hypothesis and dynamical systems
No full textThe possible connection of Riemann's Hypothesis on the non trivial zeroes of the zeta function ζ(z) with the theory of dynamical systems, both quantum and classical, is discussed. The conjecture of the existence of an underlying integrable structure is analysed, resorting on the one hand to the link between Riemann's zeta function and the Selberg trace formula, on the other to the relation between the zeroes of ζ(z) and the Gauss unitary ensemble of random matrices, to which – through basic results on the twisted de Rham cohomology – a holonomic system of completely integrable differential equations can be associated
Environmental education in Italy - A Project about a transverse approach in the Junior High School
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Explicit predictor-multicorrector time discontinuous Galerkin methods for non-linear dynamics
No full textExplicit predictor-multicorrector time discontinuous Galerkin (TDG) methods developed for linear structural dynamics are formulated and implemented in a form suitable for arbitrary non-linear analysis of structural dynamics problems. The formulation is intended to inherit the accuracy properties of the exact parent implicit TDG methods. To this end, suitable predictors and correctors are designed to achieve third order accuracy, large stability limits and controllable numerical dissipation by means of an algorithmic parameter. As the study of a general non-linear case is rather complex, the analysis of the convergence properties of the resulting algorithms are restricted to conservative Duffing oscillators, for which closed-form solutions are available. It is shown that the main properties of the underlying parent scheme can be retained. Finally, results of representative numerical simulations relevant to Duffing oscillators and to a stiff spring pendulum discretized with finite elements illustrate the performance of the numerical schemes and confirm the analytical estimates. (C) 2002 Elsevier Science Ltd. All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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