An Analysis of the Real Interest Rate Under Regime Shifts

This study considers the time series behavior of the U.S. real interest rate from 1961 to 1986. We provide a statistical characterization of the series using the methodology of Hamilton (1989), by allowing three possible regimes affecting both the mean and variance of the series. The results suggest that the ex-post real interest rate is essentially random around a mean that is different for the periods 1961-1973, 1973-1980 and 1980-1986. The variance of the process is also different in these episodes being higher in both the 1973-1980 and 1980-1986 sub-periods. The inflation rate series is also analyzed using a three regime framework and again our results show interesting patterns with shifts in both mean and variance. Various model selection tests are run and both an ex-ante real interest rate and an expected inflation series are constructed. Finally, we make clear how our results can explain some recent findings in the literature. Cette étude s'intéresse au comportement des séries du taux d'intérêt réel américain de 1961 à 1986. En utilisant la méthodologie d'Hamilton (1989), la modélisation statistique des séries se fait en postulant trois régimes possibles affectant la moyenne et la variance de celles-ci. Les résultats suggèrent que le taux d'intérêt réel ex-post est essentiellement un processus non corrélé et centré sur une moyenne qui diffère sur les périodes 1961-1973, 1973-1980 et 1980-1986. La variance du processus est aussi différente pour chacune de ces périodes, étant plus élevée dans les sous périodes 1973-1980 et 1980-1986. Les séries du taux d'inflation sont aussi analysées à la lumière de ce modèle à trois régimes et les résultats traduisent encore un comportement intéressant de celles-ci, avec des changements dans la moyenne et la variance. Différents tests de spécification sont utilisés et des séries, à la fois du taux d'intérêt réel ex-ante et de l'inflation anticipée, sont construites. Enfin, il est montré comment ces résultats peuvent expliquer certaines conclusion récentes de la littérature.Nonstationary series; Inflation rate; Unit root; Structural change, Séries non-stationnaires ; Taux d'inflation ; Racine unitaire ; Changement structurel

LIGO Lo(g)Normal MACHO: Primordial Black Holes survive SN lensing constraints

It has been claimed in Ref.[arXiv:1712.02240] that massive primordial black holes (PBH) cannot constitute all of the dark matter (DM), because their gravitational-lensing imprint on the Hubble diagram of type Ia supernovae (SN) would be incompatible with present observations. In this paper, we critically review those constraints and find several caveats on the analysis. First of all, the constraints on the fraction $\alpha$ of PBH in matter seem to be driven by a very restrictive choice of priors on the cosmological parameters. In particular, the degeneracy between $\Omega_{\rm M}$ and $\alpha$ is ignored and thus, by fixing $\Omega_{\rm M}$, transferred the constraining power of SN magnitudes to $\alpha$. Furthermore, by considering more realistic physical sizes for the type-Ia supernovae, we find an effect on the SN lensing magnification distribution that leads to significantly looser constraints. Moreover, considering a wide mass spectrum of PBH, such as a lognormal distribution, further softens the constraints from SN lensing. Finally, we find that the fraction of PBH that could constitute DM today is bounded by $f_{\rm PBH} < 1.09\ (1.38)$, for JLA (Union 2.1) catalogs, and thus it is perfectly compatible with an all-PBH dark matter scenario in the LIGO band.Comment: 7 pages, 7 figure

Expert supervision of conventional control systems

The objective of this paper is to outline a general concept for the design of supervising fuzzy controllers to back up or monitor a conventzonal control system. The use of fuzzy logic in an external, hierarchacal control structure provides a systematic approach to integrate heuristics in a conventional control loop. Supervising techniques become especially interesting, when the system to be controlled is highly non-linear (parameter variation, saturation of the control surfaces etc.). By the means of two application examples it will be shown, how this method can effectively be used to improve the performance of a conventional control system. Both examples are part of an extended research project that is being carried out at Akrospatiale and E.N.S.I.C.A. in France to study the role of fuzzy control for potential applications in aircraft control systems

Expert supervision of an anti-skid control system of a commercial aircraft

A rule-based supervising system that incorporates fuzzy logic has been designed to back-up a conventional anti-skid braking system (ABS). Expressing the expert knowledge about the ABS in terms of linguistic rules, the supervising fuzzy system adapts the reference wheel slip of the ABS with respect to the actual runway condition. Two approaches are presented: The first uses a simple rule-based decision logic, which evaluates a new reference slip directly from the measured system variables. The second approach employes an explicit identification of the runway condition, which is used as input information of a fuzzy system to evaluate a new reference slip. This application example demonstrates the capabilities of a parallel use of conventional control techniques and fuzzy logic

Studying the nuclear mass composition of Ultra-High Energy Cosmic Rays with the Pierre Auger Observatory

The Fluorescence Detector of the Pierre Auger Observatory measures the atmospheric depth, $X_{max}$, where the longitudinal profile of the high energy air showers reaches its maximum. This is sensitive to the nuclear mass composition of the cosmic rays. Due to its hybrid design, the Pierre Auger Observatory also provides independent experimental observables obtained from the Surface Detector for the study of the nuclear mass composition. We present $X_{max}$-distributions and an update of the average and RMS values in different energy bins and compare them to the predictions for different nuclear masses of the primary particles and hadronic interaction models. We also present the results of the composition-sensitive parameters derived from the ground level component.Comment: Proceedings of the 12th International Conference on Topics in Astroparticle and Underground Physics, TAUP 2011, Munich, German

Les climats du vignoble de Bourgogne : une construction historique

International audienceLe site des climats du vignoble de Bourgogne qui viennent d’être classés en 2015 au patrimoine de l’humanité par l’UNESCO est une oeuvre humaine, le résultat des transformations d’un milieu de culture par des sociétés qui se sont succédé sur plus de deux millénaires et qui ont marqué leur territoire de façon pérenne et durable, et ce sur une étroite et longue bande de Côte exposée vers l’Est : La Côte d’Or..

Sur les traces du plus vieux vin de Bourgogne : une image plurielle duvignoble originel

International audiencePourquoi la question de la recherche plus vieux vin de Bourgogne nous est posée lors desRencontres du Clos-Vougeot 2015 « Vin et civilisation : les étapes de l’humanisation » ?Pour la Bourgogne qui puise les ressorts de la qualité de ses vins dans son histoire, il estévident que l’ancienneté des usages, des vins, des vignobles, est le gage de la qualité du vinlui-même, même si le millésime de celui-ci ne remonte pas à plus de quelques années dans lepassé. « Ancient is beautiful » et c’est cette « patience et longueur de temps» qui justifie latradition vitivinicole bourguigonne, même si une grande partie de celle-ci est re-inventéedepuis le début du XXe siècle. Mais le plus vieux vin pose aussi la question des origines et du régime d’historicité danslequel le public se place: Le plus ancien est supposé proche de l’origine et de l’originel dansune vision évolutionniste et progressiste des oeuvres de l’humanité ; pouvoir trouver le plusvieux vin, c’est se rapprocher du terroir ancestral qui l’a produit et, peut-être, par sa hauteancienneté, justifier les normes de production et les références de la qualité actuelles en vertud’ «usages locaux, loyaux et constants ». Nous verrons donc dans cet exposé comment décliner la question « du plus vieux vin deBourgogne », pour conclure sur ce qu’apporte cette connaissance aux considérations actuellespour la vigne et le vin

Preparing an ESO proposal

13 pages, to be published in the Proceedings of the 2006 Euro Summer School "Observation and Data Reduction with the VLTI", 4-16 June 2006, Goutelas (France), http://vltischool.obs.ujf-grenoble.fr/Preparing observing proposals is a classical exercise in an observational astronomer's life. In this paper, we summarize the general requirements to write a good proposal for the ESO telescopes, and eventually obtain telescope time. We detail in particular the different proposal types, how they are evaluated by ESO, what they should contain and what to avoid. The advice given in the present paper are applicable to observing proposals for the AMBER and MIDI instruments of the VLTI, but also to other ESO instruments, and to some extent to other observatories