1,720,978 research outputs found
New Critical Matrix Models and Generalized Universality
No full textAkemann G, Vernizzi G. New Critical Matrix Models and Generalized Universality. Nucl.Phys. B. 2002;631:471-499.We study a class of one-matrix models with an action containing nonpolynomialterms. By tuning the coupling constants in the action to criticality we obtainthat the eigenvalue density vanishes as an arbitrary real power at the origin,thus defining a new class of multicritical matrix models. The correspondingmicroscopic scaling law is given and possible applications to the chiral phasetransition in QCD are discussed. For generic coupling constants off-criticalitywe prove that all microscopic correlation functions at the origin of thespectrum remain in the known Bessel universality class. An arbitrary number ofDirac mass terms can be included and the corresponding massive universality ismaintained as well. We also investigate the critical behavior at the edge ofthe spectrum: there, in contrast to the behavior at the origin, we find thesame critical exponents as derived from matrix models with a polynomial action
Macroscopic and Microscopic (Non-)Universality of Compact Support Random Matrix Theory
No full textAkemann G, Vernizzi G. Macroscopic and Microscopic (Non-)Universality of Compact Support Random Matrix Theory. Nucl.Phys. B. 2000;583(3):739-757.A random matrix model with a sigma-model like constraint, the restrictedtrace ensemble (RTE), is solved in the large-n limit. In the macroscopic limitthe smooth connected two-point resolvent G(z,w) is found to be non-universal,extending previous results from monomial to arbitrary polynomial potentials.Using loop equation techniques we give a closed though non-universal expressionfor G(z,w), which extends recursively to all higher k-point resolvents. Thesefindings are in contrast to the usual unconstrained one-matrix model. However,in the microscopic large-n limit, which probes only correlations at distance ofthe mean level spacing, we are able to show that the constraint does not modifythe universal sine-law. In the case of monomial potentials , weprovide a relation valid for finite-n between the k-point correlation functionof the RTE and the unconstrained model. In the microscopic large-n limit theycoincide which proves the microscopic universality of RTEs
A detailed study of the parametric excitation of a vertical heavy rod using the method of multiple scales
No full textAn analytical solution for the problem of an immersed flexible and vertical heavy rod subjected to a vertical top motion is developed using the multiple scales method directly applied to the partial differential equations of motion. The obtained results show good agreement with a numerical solution obtained using the finite element method for a study case. The analytical solution is then used to carry out some sensitivity studies. The effects of the structural nonlinearities, hydrodynamic and structural damping terms are investigated. It is shown that the nonlinearities play a role in defining the frequency of the top motion that causes the maximum amplitude of response, but not the value of the amplitude itself. In turn, the major role played by the hydrodynamic damping in defining the response amplitude is addressed. It is also shown that the structural damping have an important effect on the response amplitude even in the case of small damping ratio. This occurs due to the combined effect of the structural with the hydrodynamic damping. Finally, it is pointed out that small differences in the structural damping ratio can lead to significant differences in the response amplitude
A discussion regarding reduced-order modelling of inclined elastic and immersed cables under support excitation
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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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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