1,720,984 research outputs found
CELLULAR-AUTOMATA APPROACH TO SITE PERCOLATION ON Z(2) - A NUMERICAL STUDY
No full textBlanchard P, GANDOLFO D. CELLULAR-AUTOMATA APPROACH TO SITE PERCOLATION ON Z(2) - A NUMERICAL STUDY. JOURNAL OF STATISTICAL PHYSICS. 1993;73(1-2):399-408.We present a cellular automata model as a new approach to Bernoulli site percolation on the square lattice. A new macroscopic quantity is defined and numerically computed at each level step of the automata dynamics. Its limit manifests a critical behavior at a value of the site occupancy probability quite close to those obtained for site percolation on Z2 with the best-known numerical methods
On the mean Euler characteristic and mean Betti's number of the Ising model with arbitrary spin
No full textBlanchard P, Dobrovolny C, Gandolfo D, Ruiz J. On the mean Euler characteristic and mean Betti's number of the Ising model with arbitrary spin. J. Stat. Mech. 2006;2006(03): P03011
Connectivity properties of continuum percolation processes on R-2
No full textBlanchard P, Dell'Antonio G, Gandolfo D, Sirugue-Collin M. Connectivity properties of continuum percolation processes on R-2. JOURNAL OF STATISTICAL PHYSICS. 2002;106(1/2):1-22.A new approach is introduced in order to estimate the critical parameters of continuous percolation of overlapping disks in R-2 when the centres of the disks are Poisson distributed. Better insights on relevant parameters near criticality are found. Moreover, introducing a suitable connectivity length, the model is able to describe continuous percolation of any type of geometrical objects in R-2
Euler-Poincare characteristic and phase transition in the Potts model on Zeta(2)
No full textBlanchard P, Fortunato S, Gandolfo D. Euler-Poincare characteristic and phase transition in the Potts model on Zeta(2). NUCLEAR PHYSICS B. 2002;644(3):495-508.Recent results concerning the topological properties of random geometrical sets have been successfully applied to the study of the morphology of clusters in percolation theory. This approach provides an alternative way of inspecting the critical behaviour of random systems in statistical mechanics. For the 2d, q-states Potts model on the square lattice with q less than or equal to 6, intensive and accurate numerics indicates that the average of the Euler characteristic (taken with respect to the Fortuin-Kasteleyn random cluster measure) changes sign at the critical threshold of the magnetization transition. (C) 2002 Elsevier Science B.V. 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
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
Phase transition and critical behavior in a model of organized criticality
No full textBiskup M, Blanchard P, Chayes L, Gandolfo D, Krüger T. Phase transition and critical behavior in a model of organized criticality. PROBABILITY THEORY AND RELATED FIELDS. 2004;128(1):1-41.We study a model of ''organized'' criticality, where a single avalanche propagates through an a priori static (i.e., organized) sandpile configuration. The latter is chosen according to an i.i.d. distribution from a Borel probability measure rho on [0,1]. The avalanche dynamics is driven by a standard toppling rule, however, we simplify the geometry by placing the problem on a directed, rooted tree. As our main result, we characterize which rho are critical in the sense that they do not admit an infinite avalanche but exhibit a power-law decay of avalanche sizes. Our analysis reveals close connections to directed site-percolation, both in the characterization of criticality and in the values of the critical exponents
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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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