Génération des règles d'association : treillis de concepts denses

La fouille de données est l'extraction non triviale d'informations implicites, inconnues et utiles à partir des données (Piatetsky-Shapiro & Frawley, 1991). Plus récemment, la notion de systèmes de gestion de base de données inductive (SGBDI) propose l'union de la base de données traditionnelle à la fouille de données et d'une base de motifs ou patrons de données. Ces derniers sont les agents fondamentaux dans les SGBDI. Dans ce mémoire le motif examiné est le concept formel. Cependant, pour un ensemble de données (nommé contexte formel dans l'AFC) de grande taille où les données sont fortement corrélées, l'extraction peut être difficile à cause des problèmes de combinatoire inhérente à cette structure. Il est vrai que l'extraction de la collection des concepts formels fréquents, donc un iceberg plutôt qu'un treillis, est une solution. Cependant, d'une part, pour un seuil de fréquence trop faible, l'extraction des concepts formels fréquents peut demeurer difficile et la combinatoire de l'extraction demeure. D'autre part, les utilisateurs pourraient préférer conserver le treillis mais appliquer une certaine relaxation sur le formalisme des concepts formels. Cette relaxation se ferait en acceptant des exceptions dans les concepts dont les seuils sur les exceptions seraient choisis par l'utilisateur. En dernier lieu, le contexte formel pourrait bien avoir des erreurs dans ses transactions. Ces erreurs pourraient donc être la cause du nombre indu de concepts formels extraits. Une relaxation au niveau de l'extraction des concepts formels pourrait être une solution à ce problème. Notre contribution se situe au niveau d'un motif en particulier et de son mode d'extraction. Ce mémoire propose donc un concept tolérant des exceptions bornées par des seuils, soit les concepts denses et explore la possibilité d'extraire un tel motif par l'algorithme incrémentaI par cardinalité. En dépit du fait que le concept ne soit plus formel mais tolérant des exceptions, les principales notions de l'analyse formelle de concepts, (e.g. la relation de précédence, le treillis) sont fortement désirées. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Concepts formels, Concepts denses, Treillis de concepts formels, Analyse formelle de concepts, Concepts tolérant des exceptions, Algorithme d'extraction de concepts, Représentation condensée

Ultrasound Diagnosis and Follow-Up of Neonate Renal Candidiasis

Urinary tract infection by Candida Albicans is a severe condition that can occur in infants during the course of a preterm or intensive care hospitalization. Candidiasis can affect the kidney and dramatically impair renal function through involvement of the renal cortex, typically associated with potentially obstructive pelvi-caliceal fungus balls. This case report describes the case of a 4.5-month girl who developed renal candidiasis one week after her admission for upper respiratory tract infection. To manage the risk of urinary tract obstruction by fungus balls, several options were discussed and a conservative approach preferred to surgery that has a potential long-term impact on renal growth, proved effective

A Comparison of TSV Etch Metrology Techniques

International audienceWe use three metrology techniques, vertical scanning interferometry (VSI), confocal chromatic microscopy (CCM), and time domain optical coherence tomography (TD-OCT), for depth measurement of through-silicon vias (TSVs) of various cross sections and depths. The merits of these techniques are discussed and compared. Introduction While sales of semiconductor equipment broke a new record this year, many metrology needs should be addressed to support the development and production of electronic chips based on "More than Moore" scaling. Among these scaling approaches, 3D integration based on TSVs offers superior integration density and reduces interconnect length/latency. Measurements are needed to evaluate the depth uniformity of etched TSVs. Indeed, upon metal filling, geometrical variations of TSVs can affect Cu nails coplanarity and can warp the wafer, resulting in a low stacking yield. Measuring the depth of TSVs is an increasingly challenging task as the diameter of many TSVs has now shrunk to only a few microns

MICROSCOPE mission analysis, requirements and expected performance

The MICROSCOPE mission aimed to test the Weak Equivalence Principle (WEP) to a precision of $10^{-15}$. The WEP states that two bodies fall at the same rate on a gravitational field independently of their mass or composition. In MICROSCOPE, two masses of different compositions (titanium and platinum alloys) are placed on a quasi-circular trajectory around the Earth. They are the test-masses of a double accelerometer. The measurement of their accelerations is used to extract a potential WEP violation that would occur at a frequency defined by the motion and attitude of the satellite around the Earth. This paper details the major drivers of the mission leading to the specification of the major subsystems (satellite, ground segment, instrument, orbit...). Building upon the measurement equation, we derive the objective of the test in statistical and systematic error allocation and provide the mission's expected error budget.Comment: References update

Changes of dust opacity with density in the Orion A molecular cloud

We have studied the opacity of dust grains at submillimeter wavelengths by estimating the optical depth from imaging at 160, 250, 350, and 500 μm from the Herschel Gould Belt Survey and comparing this to a column density obtained from the Two Micron All Sky Survey derived color excess E(J – Ks). Our main goal was to investigate the spatial variations of the opacity due to "big" grains over a variety of environmental conditions and thereby quantify how emission properties of the dust change with column (and volume) density. The central and southern areas of the Orion A molecular cloud examined here, with NH ranging from 1.5 × 1021 cm–2 to 50 × 1021 cm–2, are well suited to this approach. We fit the multi-frequency Herschel spectral energy distributions (SEDs) of each pixel with a modified blackbody to obtain the temperature, T, and optical depth, τ1200, at a fiducial frequency of 1200 GHz (250 μm). Using a calibration of NH/E(J – Ks ) for the interstellar medium (ISM) we obtained the opacity (dust emission cross-section per H nucleon), σe(1200), for every pixel. From a value ~1 × 10–25 cm2 H–1 at the lowest column densities that is typical of the high-latitude diffuse ISM, σe(1200) increases as N 0.28H over the range studied. This is suggestive of grain evolution. Integrating the SEDs over frequency, we also calculated the specific power P (emission power per H) for the big grains. In low column density regions where dust clouds are optically thin to the interstellar radiation field (ISRF), P is typically 3.7 × 10–31 W H–1, again close to that in the high-latitude diffuse ISM. However, we find evidence for a decrease of P in high column density regions, which would be a natural outcome of attenuation of the ISRF that heats the grains, and for localized increases for dust illuminated by nearby stars or embedded protostars

Biomechanical simulations of the scoliotic deformation process in the pinealectomized chicken: a preliminary study

<p>Abstract</p> <p>Background</p> <p>The basic mechanisms whereby mechanical factors modulate the metabolism of the growing spine remain poorly understood, especially the role of growth adaptation in spinal disorders like in adolescent idiopathic scoliosis (AIS). This paper presents a finite element model (FEM) that was developed to simulate early stages of scoliotic deformities progression using a pinealectomized chicken as animal model.</p> <p>Methods</p> <p>The FEM includes basic growth and growth modulation created by the muscle force imbalance. The experimental data were used to adapt a FEM previously developed to simulate the scoliosis deformation process in human. The simulations of the spine deformation process are compared with the results of an experimental study including a group of pinealectomized chickens.</p> <p>Results</p> <p>The comparison of the simulation results of the spine deformation process (Cobb angle of 37°) is in agreement with experimental scoliotic deformities of two representative cases (Cobb angle of 41° and 30°). For the vertebral wedging, a good agreement is also observed between the calculated (28°) and the observed (25° – 30°) values.</p> <p>Conclusion</p> <p>The proposed biomechanical model presents a novel approach to realistically simulate the scoliotic deformation process in pinealectomized chickens and investigate different parameters influencing the progression of scoliosis.</p

PDRs4All IV. An embarrassment of riches: Aromatic infrared bands in the Orion Bar

(Abridged) Mid-infrared observations of photodissociation regions (PDRs) are dominated by strong emission features called aromatic infrared bands (AIBs). The most prominent AIBs are found at 3.3, 6.2, 7.7, 8.6, and 11.2 $\mu$m. The most sensitive, highest-resolution infrared spectral imaging data ever taken of the prototypical PDR, the Orion Bar, have been captured by JWST. We provide an inventory of the AIBs found in the Orion Bar, along with mid-IR template spectra from five distinct regions in the Bar: the molecular PDR, the atomic PDR, and the HII region. We use JWST NIRSpec IFU and MIRI MRS observations of the Orion Bar from the JWST Early Release Science Program, PDRs4All (ID: 1288). We extract five template spectra to represent the morphology and environment of the Orion Bar PDR. The superb sensitivity and the spectral and spatial resolution of these JWST observations reveal many details of the AIB emission and enable an improved characterization of their detailed profile shapes and sub-components. While the spectra are dominated by the well-known AIBs at 3.3, 6.2, 7.7, 8.6, 11.2, and 12.7 $\mu$m, a wealth of weaker features and sub-components are present. We report trends in the widths and relative strengths of AIBs across the five template spectra. These trends yield valuable insight into the photochemical evolution of PAHs, such as the evolution responsible for the shift of 11.2 $\mu$m AIB emission from class B$_{11.2}$ in the molecular PDR to class A$_{11.2}$ in the PDR surface layers. This photochemical evolution is driven by the increased importance of FUV processing in the PDR surface layers, resulting in a "weeding out" of the weakest links of the PAH family in these layers. For now, these JWST observations are consistent with a model in which the underlying PAH family is composed of a few species: the so-called 'grandPAHs'.Comment: 25 pages, 10 figures, to appear in A&