8,396 research outputs found
Patterns of creation and usage of wikipedia content
This is the Post-print version of the Article. The official Published version can be accessed from the link below - Copyright @ 2012 IEEEWikipedia is the largest online service storing user-generated content. Its pages are open to anyone for addition, deletion and modifications, and the effort of contributors is recorded and can be tracked in time. Although potentially the Wikipedia web content could exhibit unbounded growth, it is still not clear whether the effort
of developers and the output generated are actually following patterns of continuous growth. It is also not clear how the users access such content, and if recurring patterns of usage are detectable showing how the Wikipedia content typically is viewed by interested readers. Using the category of Wikipedia as macro-agglomerates, this study reveals that Wikipedia categories face a decreasing growth trend over time, after an initial, exponential phase of development. On the other hand the study demonstrates that
the number of views to the pages within the categories follow a linear, unbounded growth.
The link between software usefulness and the need for software maintenance over time has been established by Lehman and other; the link betweenWikipedia usage and changes to the content, unlike software, appear to follow a two-phase evolution of production followed by consumption.This study is partly funded by the University of East London
Transition amplitude, partition function and the role of physical degrees of freedom in gauge theories
This work explores the quantum dynamics of the interaction between scalar
(matter) and vectorial (intermediate) particles and studies their thermodynamic
equilibrium in the grand-canonical ensemble. The aim of the article is to
clarify the connection between the physical degrees of freedom of a theory in
both the quantization process and the description of the thermodynamic
equilibrium, in which we see an intimate connection between physical degrees of
freedom, Gibbs free energy and the equipartition theorem. We have split the
work into two sections. First, we analyze the quantum interaction in the
context of the generalized scalar Duffin-Kemmer-Petiau quantum electrodynamics
(GSDKP) by using the functional formalism. We build the Hamiltonian structure
following the Dirac methodology, apply the Faddeev-Senjanovic procedure to
obtain the transition amplitude in the generalized Coulomb gauge and, finally,
use the Faddeev-Popov-DeWitt method to write the amplitude in covariant form in
the no-mixing gauge. Subsequently, we exclusively use the Matsubara-Fradkin
(MF) formalism in order to describe fields in thermodynamical equilibrium. The
corresponding equations in thermodynamic equilibrium for the scalar, vectorial
and ghost sectors are explicitly constructed from which the extraction of the
partition function is straightforward. It is in the construction of the
vectorial sector that the emergence and importance of the ghost fields are
revealed: they eliminate the extra non-physical degrees of freedom of the
vectorial sector thus maintaining the physical degrees of freedom
Competition interfaces and second class particles
The one-dimensional nearest-neighbor totally asymmetric simple exclusion
process can be constructed in the same space as a last-passage percolation
model in Z^2. We show that the trajectory of a second class particle in the
exclusion process can be linearly mapped into the competition interface between
two growing clusters in the last-passage percolation model. Using technology
built up for geodesics in percolation, we show that the competition interface
converges almost surely to an asymptotic random direction. As a consequence we
get a new proof for the strong law of large numbers for the second class
particle in the rarefaction fan and describe the distribution of the asymptotic
angle of the competition interface.Comment: Published at http://dx.doi.org/10.1214/009117905000000080 in the
Annals of Probability (http://www.imstat.org/aop/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Causal Propagators for Algebraic Gauges
Applying the principle of analytic extension for generalized functions we
derive causal propagators for algebraic non-covariant gauges. The so generated
manifestly causal gluon propagator in the light-cone gauge is used to evaluate
two one-loop Feynman integrals which appear in the computation of the
three-gluon vertex correction. The result is in agreement with that obtained
through the usual prescriptions.Comment: LaTex, 09 pages, no figure
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