2,493 research outputs found
Role of magnetic interactions in neutron stars
In this work, we present a calculation of the non-Fermi liquid correction to
the specific heat of magnetized degenerate quark matter present at the core of
the neutron star. The role of non-Fermi liquid corrections to the neutrino
emissivity has been calculated beyond leading order. We extend our result to
the evaluation of the pulsar kick velocity and cooling of the star due to such
anomalous corrections and present a comparison with the simple Fermi liquid
case.Comment: 6 pages, Proceedings of the 3rd International Conference on New
Frontiers in Physics, Kolymbari, Crete, Greece (matches published version
Manipulation under k-approval scoring rules
Under a k-approval scoring rule each agent attaches a score of one to his k most preferred alternatives and zero to the other alternatives. The rule assigns the set of alternatives with maximal score. Agents may extend preferences to sets in several ways: they may compare the worst alternatives, or the best alternatives, or use a stochastic dominance criterion. In this paper we characterize the non-manipulable profiles for each of these set comparisons. For two-agent profiles we also determine the value(s) of k for which the number of non-manipulable profiles is maximal.microeconomics ;
On the manipulability of approval voting and related scoring rules
We characterize all preference profiles at which the approval (voting) rule is manipulable, under three extensions of preferences to sets of alternatives: by comparison of worstalternatives, best alternatives, or by comparison based on stochastic dominance. We perform a similar exercise for -approval rules, where voters approve of a fixed number of alternatives. These results can be used to compare (-)approval rules with respect to their manipulability. Analytical results are obtained for the case of two voters, specifically, the values of for which the -approval rule is minimally manipulable -- has the smallest number of manipulable preference profiles -- under the various preference extensions are determined. For the number of voters going to infinity, an asymptotic result is that the -approval rule with around half the number of alternatives is minimally manipulable among all scoring rules. Further results are obtained by simulation and indicate that -approval rules may improve on the approval rule as far as manipulability is concerned.public economics ;
A Survey of Cellular Automata: Types, Dynamics, Non-uniformity and Applications
Cellular automata (CAs) are dynamical systems which exhibit complex global
behavior from simple local interaction and computation. Since the inception of
cellular automaton (CA) by von Neumann in 1950s, it has attracted the attention
of several researchers over various backgrounds and fields for modelling
different physical, natural as well as real-life phenomena. Classically, CAs
are uniform. However, non-uniformity has also been introduced in update
pattern, lattice structure, neighborhood dependency and local rule. In this
survey, we tour to the various types of CAs introduced till date, the different
characterization tools, the global behaviors of CAs, like universality,
reversibility, dynamics etc. Special attention is given to non-uniformity in
CAs and especially to non-uniform elementary CAs, which have been very useful
in solving several real-life problems.Comment: 43 pages; Under review in Natural Computin
The Clouds in Asynchronous Cellular Automata
This article introduces the notion of clouds in asynchronous cellular
automata (ACAs). We show that the cloud behaviour of ACAs has similarity with
natural clouds across the sky, election model of parliamentary democratic
system, and electron cloud around nucleus. These systems, therefore, can be
modelled by the ACAs
A high contrast and resolution reconstruction algorithm in quantitative photoacoustic tomography
A framework for reconstruction of optical diffusion and absorption
coefficients in quantitative photoacoustic tomography is presented. This
framework is based on a Tikhonov-type functional with a regularization term
promoting sparsity of the absorption coefficient and a prior involving a
Kubelka-Munk absorption-diffusion relation that allows to obtain superior
reconstructions. The reconstruction problem is formulated as the minimization
of this functional subject to the differential constraint given by a
photon-propagation model. The solution of this problem is obtained by a fast
and robust sequential quadratic hamiltonian algorithm based on the Pontryagin
maximum principle. Results of several numerical experiments demonstrate that
the proposed computational strategy is able to obtain reconstructions of the
optical coefficients with high contrast and resolution for a wide variety of
objects
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