118,028 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
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
No full textThe 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
Thermodynamic Transformations of Nonequilibrium States
No full textWe consider a macroscopic system in contact with boundary reservoirs and/or under the action of an external field. We discuss the case in which the external forcing depends explicitly on time and drives the system from a nonequilibrium state to another one. In this case the amount of energy dissipated along the transformation becomes infinite when an unbounded time window is considered. Following the general proposal by Oono and Paniconi and using results of the macroscopic fluctuation theory, we give a natural definition of a renormalized work. We then discuss its thermodynamic relevance by showing that it satisfies a Clausius inequality and that quasi static transformations minimize the renormalized work. In addition, we connect the renormalized work to the quasi potential describing the fluctuations in the stationary nonequilibrium ensemble. The latter result provides a characterization of the quasi potential that does not involve rare fluctuations
Clausius Inequality and Optimality of Quasistatic Transformations for Nonequilibrium Stationary States
No full textNonequilibrium stationary states of thermodynamic systems dissipate a positive amount of energy per unit of time. If we consider transformations of such states that are realized by letting the driving depend on time, the amount of energy dissipated in an unbounded time window then becomes infinite. Following the general proposal by Oono and Paniconi and using results of the macroscopic fluctuation theory, we give a natural definition of a renormalized work performed along any given transformation. We then show that the renormalized work satisfies a Clausius inequality and prove that equality is achieved for very slow transformations, that is, in the quasistatic limit. We finally connect the renormalized work to the quasipotential of the macroscopic fluctuation theory, which gives the probability of fluctuations in the stationary nonequilibrium ensemble. DOI: 10.1103/PhysRevLett.110.02060
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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
Letter from unknown writer to Jesse L. Boyce
No full textLetter to Jesse L. Boyce from unknown author (possibly Jack) about the investigation into the powder magazine located in the Grand Canyon. Some personal news is included in the letter such as the writer's marriage to the daughter of C.A. Taylor, former Supervisor of Cochise County
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
Sarah L. Blum Author Visit - Warrior Nurse: PTSD and Healing
No full textHear Sarah L. Blum, author of Women Under Fire: Abuse in the Military, discuss her newest book, Warrior Nurse: PTSD and Healing followed by a Q&A and book signing.
Sarah L. Blum is a decorated Vietnam veteran who served as an operating room nurse during the intense fighting of 1967. In recognition of her service, she was awarded the Army Commendation Medal.
Sponsored by CWU Veterans Center and CWU Libraries.https://digitalcommons.cwu.edu/libraryevents/1252/thumbnail.jp
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