49,139 research outputs found
Generalized master equations leading to completely positive dynamics
We provide a general construction of quantum generalized master equations
with memory kernel leading to well defined, that is completely positive and
trace preserving, time evolutions. The approach builds on an operator
generalization of memory kernels appearing in the description of non-Markovian
classical processes, and puts into evidence the non uniqueness of the
relationship arising due to the typical quantum issue of operator ordering. The
approach provides a physical interpretation of the structure of the kernels,
and its connection with the classical viewpoint allows for a trajectory
description of the dynamics. Previous apparently unrelated results are now
connected in a unified framework, which further allows to phenomenologically
construct a large class of non-Markovian evolutions taking as starting point
collections of time dependent maps and instantaneous transformations describing
the microscopic interaction dynamics.Comment: 8 pages, to appear on PR
Maximum entropy generation in open systems: the Fourth Law?
This paper develops an analytical and rigorous formulation of the maximum
entropy generation principle. The result is suggested as the Fourth Law of
Thermodynamics
Optimal Inference in Crowdsourced Classification via Belief Propagation
Crowdsourcing systems are popular for solving large-scale labelling tasks
with low-paid workers. We study the problem of recovering the true labels from
the possibly erroneous crowdsourced labels under the popular Dawid-Skene model.
To address this inference problem, several algorithms have recently been
proposed, but the best known guarantee is still significantly larger than the
fundamental limit. We close this gap by introducing a tighter lower bound on
the fundamental limit and proving that Belief Propagation (BP) exactly matches
this lower bound. The guaranteed optimality of BP is the strongest in the sense
that it is information-theoretically impossible for any other algorithm to
correctly label a larger fraction of the tasks. Experimental results suggest
that BP is close to optimal for all regimes considered and improves upon
competing state-of-the-art algorithms.Comment: This article is partially based on preliminary results published in
the proceeding of the 33rd International Conference on Machine Learning (ICML
2016
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Information Behavior and Political Preferences
This article shows that citizens consider policy positions for the formation of their political preferences when they actively seek and find high-quality information, while they dismiss passively acquired and low-quality information. The study develops an extended theory of information and political preferences that incorporates the process of information acquisition and its connection with information quality. A novel experimental design separates the effects on political preferences due to information behavior as an activity from those due to selective exposure to information. The study applies this design in a laboratory experiment with a diverse group of participants using the example of issue voting and European integration in the context of the 2014 European Parliament elections
An introduction to DSmT
The management and combination of uncertain, imprecise, fuzzy and even
paradoxical or high conflicting sources of information has always been, and
still remains today, of primal importance for the development of reliable
modern information systems involving artificial reasoning. In this
introduction, we present a survey of our recent theory of plausible and
paradoxical reasoning, known as Dezert-Smarandache Theory (DSmT), developed for
dealing with imprecise, uncertain and conflicting sources of information. We
focus our presentation on the foundations of DSmT and on its most important
rules of combination, rather than on browsing specific applications of DSmT
available in literature. Several simple examples are given throughout this
presentation to show the efficiency and the generality of this new approach
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