1,620 research outputs found
An option on the average European futures prices for an efficient hog producer risk management
The volatility of hog prices is high compared to most agricultural commodities. However, European hog producers do not benefit from any agricultural policy support. Through the continuous production process and induced selling activity on spot markets, producers benefit from a natural moving average product pricing. In addition, asymmetric price risk management is able to increase the expected utility of risk adverse hog producers. But, if there is a futures contract at the European Exchange (EUREX), there is no option market and as a consequence no derivative contracts on the European hog market. The article is presenting how financial intermediaries could offer an innovative derivative contract to complement the “naturall ” steady price of the French hog producers.price risk, margin risk, hog, futures market, replication portfolio, hedging
Detection of multiplicative noise in stationary random processes using second- and higher order statistics
This paper addresses the problem of detecting the presence of colored multiplicative noise, when the information process can be modeled as a parametric ARMA process. For the case of zero-mean multiplicative noise, a cumulant based suboptimal detector is studied. This detector tests the nullity of a specific cumulant slice. A second detector is developed when the multiplicative noise is nonzero mean. This detector consists of filtering the data by an estimated AR filter. Cumulants of the residual data are then shown to be well suited to the detection problem. Theoretical expressions for the asymptotic probability of
detection are given. Simulation-derived finite-sample ROC curves are shown for different sets of model parameters
Lorentz Force Electrical Impedance Tomography
This article describes a method called Lorentz Force Electrical Impedance
Tomography. The electrical conductivity of biological tissues can be measured
through their sonication in a magnetic field: the vibration of the tissues
inside the field induces an electrical current by Lorentz force. This current,
detected by electrodes placed around the sample, is proportional to the
ultrasonic pressure, to the strength of the magnetic field and to the
electrical conductivity gradient along the acoustic axis. By focusing at
different places inside the sample, a map of the electrical conductivity
gradient can be established. In this study experiments were conducted on a
gelatin phantom and on a beef sample, successively placed in a 300 mT magnetic
field and sonicated with an ultrasonic transducer focused at 21 cm emitting 500
kHz bursts. Although all interfaces are not visible, in this exploratory study
a good correlation is observed between the electrical conductivity image and
the ultrasonic image. This method offers an alternative to detecting
pathologies invisible to standard ultrasonography
Hommage à Bastien Irondelle, 1973-2013
Les témoignages qui affluent depuis la disparition de Bastien Irondelle soulignent la générosité, l’intégrité et l’engagement intellectuel du jeune professeur de Sciences Po Paris. Ces qualités, reconnues de tous ne doivent pas nous faire oublier qu’il a aussi été un chercheur prolifique au CERI. En une décennie, Bastien Irondelle a publié pas moins de 4 ouvrages, 17 chapitres de livres, 21 articles scientifiques, 12 recensions ou lectures critiques et 11 rapports de recherche mandatés. Ce court texte résume les principales contributions de notre collègue et ami, décédé au Mans le 27 septembre 2013 [Premier paragraphe]
Joint Bayesian endmember extraction and linear unmixing for hyperspectral imagery
This paper studies a fully Bayesian algorithm for endmember extraction and
abundance estimation for hyperspectral imagery. Each pixel of the hyperspectral
image is decomposed as a linear combination of pure endmember spectra following
the linear mixing model. The estimation of the unknown endmember spectra is
conducted in a unified manner by generating the posterior distribution of
abundances and endmember parameters under a hierarchical Bayesian model. This
model assumes conjugate prior distributions for these parameters, accounts for
non-negativity and full-additivity constraints, and exploits the fact that the
endmember proportions lie on a lower dimensional simplex. A Gibbs sampler is
proposed to overcome the complexity of evaluating the resulting posterior
distribution. This sampler generates samples distributed according to the
posterior distribution and estimates the unknown parameters using these
generated samples. The accuracy of the joint Bayesian estimator is illustrated
by simulations conducted on synthetic and real AVIRIS images
Acousto-electrical speckle pattern in Lorentz force electrical impedance tomography
Ultrasound speckle is a granular texture pattern appearing in ultrasound
imaging. It can be used to distinguish tissues and identify pathologies.
Lorentz force electrical impedance tomography is an ultrasound-based medical
imaging technique of the tissue electrical conductivity. It is based on the
application of an ultrasound wave in a medium placed in a magnetic field and on
the measurement of the induced electric current due to Lorentz force. Similarly
to ultrasound imaging, we hypothesized that a speckle could be observed with
Lorentz force electrical impedance tomography imaging. In this study, we first
assessed the theoretical similarity between the measured signals in Lorentz
force electrical impedance tomography and in ultrasound imaging modalities. We
then compared experimentally the signal measured in both methods using an
acoustic and electrical impedance interface. Finally, a bovine muscle sample
was imaged using the two methods. Similar speckle patterns were observed. This
indicates the existence of an "acousto-electrical speckle" in the Lorentz force
electrical impedance tomography with spatial characteristics driven by the
acoustic parameters but due to electrical impedance inhomogeneities instead of
acoustic ones as is the case of ultrasound imaging
Economie politique de la réforme de transition fiscale : le cas du Maroc
L'objet de cet article est de mettre en évidence le rôle crucial dans les réformes des facteurs d'économie politique très souvent négligés dans les pays en développement mais qui, ces dernières années, ont constitué un obstacle très important aux réformes de transition fiscale. Les auteurs ont considéré le cas du Maroc. Dans ce pays, les autorités utilisent de nombreux instruments pour agir sur des facteurs d'économie politique et créer un climat favorable à un programme ambitieux de réforme fiscale. Des constats de cette analyse peuvent certainement être tirées des leçons utiles pour les nombreux pays en développement s'engageant dans des réformes similaires
Marketing Management and Communications in the Public Sector
This updated edition of Marketing Management and Communications in the Public Sector provides a thorough overview of the major concepts in public sector marketing and communications, two fields that have continued to grow in importance for modern public administrations. With extended coverage of topics such as social marketing and institutional communication, the authors skilfully build on the solid foundations laid down in the previous edition. Replete with real-world case studies and examples, including new material from the USA, Australia, and Asia, this book gives students a truly international outlook. Additional features include exercises and discussion questions in each chapter and an illustrative extended case study. This refreshed text is essential reading for postgraduate students on public management degrees, and aspiring or current public managers. The Open Access version of this book, available at http://www.taylorfrancis.com/books/e/9781315622309, has been made available under a Creative Commons Attribution-Non Commercial-No Derivatives 4.0 license
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