A Note on Easy and Efficient Computation of Full Abelian Periods of a Word

Constantinescu and Ilie (Bulletin of the EATCS 89, 167-170, 2006) introduced the idea of an Abelian period with head and tail of a finite word. An Abelian period is called full if both the head and the tail are empty. We present a simple and easy-to-implement $O(n\log\log n)$-time algorithm for computing all the full Abelian periods of a word of length $n$ over a constant-size alphabet. Experiments show that our algorithm significantly outperforms the $O(n)$ algorithm proposed by Kociumaka et al. (Proc. of STACS, 245-256, 2013) for the same problem.Comment: Accepted for publication in Discrete Applied Mathematic

Daily and seasonal variations in the spatial distribution of zooplankton populations in relation to the physical structure in the Ligurian Sea Front

Results from five hydrographic and biological surveys at different seasons across the Ligurian Sea front, using horizontal continuous measurements and vertical profiles are presented. The vertical circulation across the front is described, and two divergences and one convergence are identified as permanent features from data. The key to find their location for each survey is given. The spatial patterns of 14 zooplankton taxa along the transect are established using variance analysis, principal component and correspondence analyses. The spatial distribution of each taxon is related to the physical structure, and the convection cells evidenced by the scheme appear as different biotopes. The daily variability of the spatial distributions is negligible compared to the annual variability. Distinctions are made between coastal species always inhabiting the peripheral (coastal zone) and others with distinct coastal, frontal and offshore distributions varying with the season. For the latter species the frontal zone is a preferential biotope during their seasonal growth period. Consequently the accumulation of organisms near the convergence cannot be created by only the dynamic causes. The role of biological processes in the observed distributions is discussed

A latitude-dependent wind model for Mira's cometary head

We present a 3D numerical simulation of the recently discovered cometary structure produced as Mira travels through the galactic ISM. In our simulation, we consider that Mira ejects a steady, latitude-dependent wind, which interacts with a homogeneous, streaming environment. The axisymmetry of the problem is broken by the lack of alignment between the direction of the relative motion of the environment and the polar axis of the latitude-dependent wind. With this model, we are able to produce a cometary head with a ``double bow shock'' which agrees well with the structure of the head of Mira's comet. We therefore conclude that a time-dependence in the ejected wind is not required for reproducing the observed double bow shock.Comment: 4 pages, 4 figures, accepted for publication in ApJ

Energy analysis of organic crop systems. Impact of intensification level.

This study reveals a wide variability in the major parameters of the energy analysis applied to 44 four-year-long organic crop sequences. The intensification level of the systems in terms of the use or nonuse of organic fertilisation on cereals and of irrigation on summer crops (mainly pulses) is largely responsible for this variability. Average energy consumption ranges from 5 000 to 12 270 MJ/ha/year depending on the intensification level. Energy production varies from 35 500 to 43 950 MJ/ha/year. Since energy consumption and production both vary in the same direction with the degree of intensification, the energy gain is stable at an average value of 29300 MJ/ha/year. Energy efficiency decreases from 7.1 MJ/MJ for unfertilised and unirrigated crop sequences, to 3.5 MJ/MJ for fertilised and irrigated sequences, where soy and faba bean are among the major crops

Adaptive density estimation for stationary processes

We propose an algorithm to estimate the common density $s$ of a stationary process $X_1,...,X_n$. We suppose that the process is either $\beta$ or $\tau$-mixing. We provide a model selection procedure based on a generalization of Mallows' $C_p$ and we prove oracle inequalities for the selected estimator under a few prior assumptions on the collection of models and on the mixing coefficients. We prove that our estimator is adaptive over a class of Besov spaces, namely, we prove that it achieves the same rates of convergence as in the i.i.d framework

Time series prediction via aggregation : an oracle bound including numerical cost

We address the problem of forecasting a time series meeting the Causal Bernoulli Shift model, using a parametric set of predictors. The aggregation technique provides a predictor with well established and quite satisfying theoretical properties expressed by an oracle inequality for the prediction risk. The numerical computation of the aggregated predictor usually relies on a Markov chain Monte Carlo method whose convergence should be evaluated. In particular, it is crucial to bound the number of simulations needed to achieve a numerical precision of the same order as the prediction risk. In this direction we present a fairly general result which can be seen as an oracle inequality including the numerical cost of the predictor computation. The numerical cost appears by letting the oracle inequality depend on the number of simulations required in the Monte Carlo approximation. Some numerical experiments are then carried out to support our findings

2004 ATLAS Combined Testbeam : Computation and Validation of the Electronic Calibration Constants for the Electromagnetic Calorimeter

From July to November 2004, a full slice of the ATLAS barrel detector was studied in testbeam. A complete electromagnetic barrel module was used, read by the final electronics and operated by ATLAS TDAQ software. This note describes in details the electronic calibration procedure and the cell energy reconstruction: each step of the procedure and its associated software is explicitly described. The general calibration procedure is very similar to the one applied in previous barrel and endcap standalone testbeams. Emphasis is put on tools developed in the context of the combined testbeam which can be used for commissioning and operation of the calorimeters in ATLAS. Many validation studies were performed on each calibration constant. Previously unobserved effects such as the FEB temperature dependence of some constants were observed. Overall, the calibration performances are at the expected level

Modélisation des déplacements de barrages

En dépit de leur immobilité apparente, les barrages se meuvent au cours de leur exploitation. Ils sont surveillés par le biais d'une activité dite d'auscultation d'ouvrages (exploitation de mesures de débit, de contraintes, de déplacement ...) qui permet de se prononcer sur leur état de santé. On se propose de mettre en oeuvre des algorithmes de soustraction de bruit - le bruit correspondant aux contributions perturbatrices de la côte et de la température -afin d'en extraire la composante utile : la composante de fatigue du barrage. Les algorithmes ont été adaptés au contexte non stationnaire des mesures (évolution des fonctions de transfert des ouvrages) ainsi qu'à l'irrégularité de la mesure de sortie et aux nonlinéarités existant entre certaines entrées-sorties

Position resolution and particle identification with the ATLAS EM calorimeter

In the years between 2000 and 2002 several pre-series and series modules of the ATLAS EM barrel and end-cap calorimeter were exposed to electron, photon and pion beams. The performance of the calorimeter with respect to its finely segmented first sampling has been studied. The polar angle resolution has been found to be in the range 50-60 mrad/sqrt(E (GeV)). The neutral pion rejection has been measured to be about 3.5 for 90% photon selection efficiency at pT=50 GeV/c. Electron-pion separation studies have indicated that a pion fake rate of (0.07-0.5)% can be achieved while maintaining 90% electron identification efficiency for energies up to 40 GeV.Comment: 32 pages, 22 figures, to be published in NIM