1,721,173 research outputs found
Complexity for extended dynamical systems
Get PDFWe consider dynamical systems for which the spatial extension plays an important role. For these systems, the notions of attractor, ε-entropy and topological entropy per unit time and volume have been introduced previously. In this paper we use the notion of Kolmogorov complexity to introduce, for extended dynamical systems, a notion of complexity per unit time and volume which plays the same role as the metric entropy for classical dynamical systems. We introduce this notion as an almost sure limit on orbits of the system. Moreover we prove a kind of variational principle for this complexity
On the essential spectrum of the transfer operator for expanding markov maps
No full textThe essential spectrum of the transfer operator for expanding markov maps of the interval is studied in detail. To this end we construct explicitly an infinite set of eigenfunctions which allows us to prove that the essential spectrum in C_k is a disk whose radius is related to the free energy of the Liapunov exponent
Concentration inequalities for random fields via coupling
Get PDFWe present a new and simple approach to concentration inequalities in the context of dependent random processes and random fields. Our method is based on coupling and does not use information inequalities. In case one has a uniform control on the coupling, one obtains exponential concentration inequalities. If such a uniform control is no more possible, then one obtains polynomial or stretched-exponential concentration inequalities. Our abstract results apply to Gibbs random fields, both at high and low temperatures and in particular to the low-temperature Ising model which is a concrete example of non-uniformity of the coupling.
Caen, cité médiévale : C. Collet, P. Leroux, J.Y. Marin, Caen, cité médiévale. Bilan d'archéologie et d'histoire
No full textNeveux Hugues. Caen, cité médiévale : C. Collet, P. Leroux, J.Y. Marin, Caen, cité médiévale. Bilan d'archéologie et d'histoire. In: Annales de Normandie, 46ᵉ année, n°5, 1996. Société d'Ancien Régime : Journée d'Histoire du Droit – 1995. pp. 757-759
Estimates of Kolmogorov complexity in approximating Cantor sets
No full textOur aim is to quantify how complex a Cantor set is as we approximate it better and better. We formalize this by asking what is the shortest program, running on a universal Turing machine, which produces this set at the precision in the sense of Hausdorff distance. This is the Kolmogorov complexity of the approximated Cantor set, which we call the "-distortion complexity". How does this quantity behave as tends to 0? And, moreover, how this behaviour relates to other characteristics of the Cantor set? This is the subject of this work: we estimate this quantity for several types of Cantor sets on the line generated by iterated function systems and exhibit very different behaviours. For instance, the -distortion complexity of most Cantor sets is proven to behave as , where D is its box counting dimension
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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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