1,721,164 research outputs found
Metastable Γ-expansion of finite state Markov chains level two large deviations rate functions.
No full textWe examine two analytical characterisation of the metastable behavior of a sequence of Markov chains. The first one expressed in terms of its transition probabilities, and the second one in terms of its large deviations rate functional.
Consider a sequence of continuous-time Markov chains (X(n)t:t≥0)
evolving on a fixed finite state space V. Under a hypothesis on the jump rates, we prove the existence of time-scales θ(p)n and probability measures with disjoint supports π(p)j, j∈Sp, 1≤p≤q, such that (a) θ(1)n→∞, θ(k+1)n/θ(k)n→∞, (b) for all p, x∈V, t>0, starting from x, the distribution of X(n)tθ(p)n converges, as n→∞, to a convex combination of the probability measures π(p)j
. The weights of the convex combination naturally depend on x and t.
Let In
be the level two large deviations rate functional for X(n)t, as t→∞. Under the same hypothesis on the jump rates and assuming, furthermore, that the process is reversible, we prove that In can be written as In=I(0)+∑1≤p≤q(1/θ(p)n)I(p) for some rate functionals I(p) which take finite values only at convex combinations of the measures π(p)j: I(p)(μ)<∞ if, and only if, μ=∑j∈Spωjπ(p)j for some probability measure ω in Sp
Onsager Reciprocity Relations Without Microscopic Reversibility
No full textIn this paper we show that Onsager-Machlup time-reversal properties of thermodynamic fluctuations
and Onsager reciprocity relations for transport coefficients can hold also if the microscopic dynamics
is not reversible. This result is based on the explicit construction of models which can be analyzed
rigorousl
Onsager Symmetry from microscopic TP invariance
No full textWe prove for a class of conservative interacting particle systems the validity of
Onsager reciprocity relations for the transport coefficients if the microscopic
dynamics is invariant under the combined action of time reversal and parity.
The situation is reminiscent of TCP invariance in quantum field theory. Our
systems include multicomponent zero-range and exchange dynamics
Strong asymmetric limit of the quasi-potential of the boundary driven weakly asymmetric exclusion process
No full textWe consider the weakly asymmetric exclusion process on a bounded
interval with particles reservoirs at the endpoints. The hydrodynamic limit for the empirical
density, obtained in the diffusive scaling, is given by the viscous Burgers equation
with Dirichlet boundary conditions. In the case in which the bulk asymmetry is in the
same direction as the drift due to the boundary reservoirs, we prove that the quasipotential
can be expressed in terms of the solution to a one-dimensional boundary value
problem which has been introduced by Enaud and Derrida [16].We consider the strong
asymmetric limit of the quasi-potential and recover the functional derived by Derrida,
Lebowitz, and Speer [15] for the asymmetric exclusion proces
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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