552 research outputs found
Spin-squeezing and Dicke state preparation by heterodyne measurement
We investigate the quantum non-demolition (QND) measurement of an atomic
population based on a heterodyne detection and show that the induced
back-action allows to prepare both spin-squeezed and Dicke states. We use a
wavevector formalism to describe the stochastic process of the measurement and
the associated atomic evolution. Analytical formulas of the atomic distribution
momenta are derived in the weak coupling regime both for short and long time
behavior, and they are in good agreement with those obtained by a Monte-Carlo
simulation. The experimental implementation of the proposed heterodyne
detection scheme is discussed. The role played in the squeezing process by the
spontaneous emission is considered
Adapting Quality Assurance to Adaptive Systems: The Scenario Coevolution Paradigm
From formal and practical analysis, we identify new challenges that
self-adaptive systems pose to the process of quality assurance. When tackling
these, the effort spent on various tasks in the process of software engineering
is naturally re-distributed. We claim that all steps related to testing need to
become self-adaptive to match the capabilities of the self-adaptive
system-under-test. Otherwise, the adaptive system's behavior might elude
traditional variants of quality assurance. We thus propose the paradigm of
scenario coevolution, which describes a pool of test cases and other
constraints on system behavior that evolves in parallel to the (in part
autonomous) development of behavior in the system-under-test. Scenario
coevolution offers a simple structure for the organization of adaptive testing
that allows for both human-controlled and autonomous intervention, supporting
software engineering for adaptive systems on a procedural as well as technical
level.Comment: 17 pages, published at ISOLA 201
A mid-infrared Mueller ellipsometer with pseudo-achromatic optical elements
The purpose of this article is to present a new broadband Mueller
ellipsometer designed to work in the mid-infrared range, from 3 to 14 microns.
The Mueller ellipsometer, which can be mounted in reflection or in transmission
configuration, consists of a polarization state generator (PSG), a sample
holder, and a polarization state analyzer (PSA). The PSG consists in one linear
polarizer and a retarder sequentially rotated to generate a set of four optimal
polarization states. The retarder consists in a bi-prism made of two identical
Fresnel rhombs disposed symmetrically and joined by optical contact, giving the
ensemble a "V" shape. Retardation is induced by the four total internal
reflections that the beam undergoes when it propagates through the bi-prism.
Total internal reflection allows to generate a quasi-achromatic retardation.
The PSA is identical to the PSG, but with its optical elements mounted in
reverse order. After a measurement run, the instrument yields a set of sixteen
independent values, which is the minimum amount of data required to calculate
the Mueller matrix of the sample. The design of the Mueller ellipsometer is
based on the optimization of an objective criterion that allows minimizing the
propagation of errors from raw data to the Mueller matrix of the sample. The
pseudo-achromatic optical elements ensure a homogeneous quality of the
measurements for all wavelengths. The performance of the Mueller ellipsometer
in terms of precision, and accuracy, is discussed and illustrated with a few
examples
A generic testing framework for agent-based simulation models
International audienceAgent-based modelling and simulation (ABMS) had an increasing attention during the last decade. However, the weak validation and verification of agent-based simulation models makes ABMS hard to trust. There is no comprehensive tool set for verification and validation of agent-based simulation models, which demonstrates that inaccuracies exist and/or reveals the existing errors in the model. Moreover, on the practical side, many ABMS frameworks are in use. In this sense, we designed and developed a generic testing framework for agent-based simulation models to conduct validation and verification of models. This paper presents our testing framework in detail and demonstrates its effectiveness by showing its applicability on a realistic agent-based simulation case study
Etude de faisabilité d'un projet d'appui aux unités de conservation de la faune au Burkina Faso. Document final et proposition de projet
Dans le cadre de la réforme de la gestion des ressources naturelles, le Burkina Faso innove avec le concept d'Unité de Conservation de la Faune. Les zones de chasse et les parcs nationaux amodiés au secteur privé doivent contribuer au développement local, subvenir en partie à leurs propres besoins de gestion pour soulager les finances publiques et conserver durablement la biodiversité en la valorisant par différents modes de tourisme : vision, grande chasse, petite chasse. Cette approche devrait être appuyée par un projet de la coopération bilatérale France/Burkina Faso au travers de l'Agence Française de Développement et au Fonds Français pour l'Environnement Mondial. Le présent document étudie la faisabilité de ce projet. Il fait suite à mon premier document dans lequel était présentée une étude détaillée du contrat. (Résumé d'auteur
Les Houches 2015: Physics at TeV colliders - new physics working group report
We present the activities of the 'New Physics' working group for the 'Physics
at TeV Colliders' workshop (Les Houches, France, 1-19 June, 2015). Our report
includes new physics studies connected with the Higgs boson and its properties,
direct search strategies, reinterpretation of the LHC results in the building
of viable models and new computational tool developments. Important signatures
for searches for natural new physics at the LHC and new assessments of the
interplay between direct dark matter searches and the LHC are also considered.Comment: Proceedings of the New Physics Working Group of the 2015 Les Houches
Workshop, Physics at TeV Colliders, Les Houches 1-19 June 2015. 197 page
Contribution to the Control of a MAS's Global Behaviour: Reinforcement Learning Tools
Reactive multi-agent systems present global behaviours uneasily linked to their local dynamics. When it comes to controlling such a system, usual analytical tools are difficult to use so specific techniques have to be engineered. We propose an experimental dynamical approach to enhance the control of the global behaviour of a reactive multi-agent system. We use reinforcement learning tools to link global information of the system to control actions. We propose to use the behaviour of the system as this global information. The behaviour of the whole system is controlled thanks to actions at different levels instead of building the behaviours of the agents, so that the complexity of the approach does not directly depend on the number of agents. The controllability is evaluated in terms of rate of convergence towards a target behaviour. We compare the results obtained on a toy example with the usual approach of parameter setting
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