Stammdatenmanagement: Datenqualität für Geschäftsprozesse

Zusammenfassung: Stammdatenmanagement ist eine Unternehmensfunktion, die sämtliche Planungs-, Überwachungs- und Bereitstellungsaktivitäten für Stammdaten umfasst und deren Ziel die Sicherung der Stammdatenqualität ist. Stammdaten von hoher Qualität sind die Voraussetzung, damit Unternehmen verschiedene strategische Anforderungen erfüllen können. Dieser Beitrag beschreibt diejenigen Bereiche, die beim Aufbau eines unternehmensweiten Stammdatenmanagements zu gestalten sin

Structural features of pyrocarbon atomistic models constructed from transmission electron microscopy images

International audienceWe report on atomistic models of laminar pyrocarbons constructed using a combination of 2D high resolution transmission electron microscopy (HRTEM) lattice fringe image analysis, 3D image synthesis and atomistic simulated annealing. In a first step, the effectiveness of the method and the convergence of the models with respect to the quench rate are checked on small systems. Then, the nanostructural features of large fully carbonaceous atomistic models obtained from the HRTEM images of a rough laminar pyrocarbon, asprepared and after partial graphitization, are discussed. Both models show a very pronounced sp2 character (≥ 97%), essentially made of hexagonal rings (≥ 88%) and pentagonal and heptagonal rings in similar amounts (≈ 6%). The latter mostly form pentagon-heptagon pairs or networks of line defects between misoriented hexagonal domains. Numerous pairs of screw dislocations, connecting different graphene domains, are also observed while edge dislocations with unsaturated carbon atoms are almost absent. The models are validated with respect to experimental pair distribution functions, showing excellent agreement

Grouping variables in Frontal Matrices to improve Low-Rank Approximations in a Multifrontal Solver

Session 3International audienc

On fiber dispersion models: exclusion of compressed fibers and spurious model comparisons

Fiber dispersion in collagenous soft tissues has an important influence on the mechanical response, and the modeling of the collagen fiber architecture and its mechanics has developed significantly over the last few years. The purpose of this paper is twofold, first to develop a method for excluding compressed fibers within a dispersion for the generalized structure tensor (GST) model, which several times in the literature has been claimed not to be possible, and second to draw attention to several erroneous and misleading statements in the literature concerning the relative values of the GST and the angular integration (AI) models. For the GST model we develop a rather simple method involving a deformation dependent dispersion parameter that allows the mechanical influence of compressed fibers within a dispersion to be excluded. The theory is illustrated by application to simple extension and simple shear in order to highlight the effect of exclusion. By means of two examples we also show that the GST and the AI models have equivalent predictive power, contrary to some claims in the literature. We conclude that from the theoretical point of view neither of these two models is superior to the other. However, as is well known and as we now emphasize, the GST model has proved to be very successful in modeling the data from experiments on a wide range of tissues, and it is easier to analyze and simpler to implement than the AI approach, and the related computational effort is much lower

Atomistic models of pyrolytic carbons obtained with the IGAR method

International audienceThis study aims at obtaining atomistic representations of these RL and ReL pyCs and at describing their nano-texture/structure. We will first describe some improvements in the IGAR method. Then, the nature of defects in these materials, in terms of non-hexagonal rings and screw dislocations, as well as their hydrogen atoms contents and locations, will be thoroughly compared and discussed. These models will also be validated against experimental HRTEM images and pair distribution functions (PDF) (and structure factors) obtained from neutron diffraction

Prédiction de la structure et des propriétés de pyrocarbones à partir d'une reconstruction à l'échelle atomique

National audienceNous présentons ici une approche originale permettant de construire des modèles à l'échelle atomique de matériaux nanotexturés à partir de leurs images de Microscopie Electronique en Transmission à Haute Résolution (HRTEM). Partant d'une image HRTEM filtrée à hautes et basses fréquences (a), un ensemble de descripteurs statistiques est collecté puis imposé à une synthèse d'image 3D aléatoire (b). Cette dernière est ensuite utilisée comme champ de potentiel attirant les atomes sur les franges lors d'une simulation de trempe d'un liquide de carbone par dynamique moléculaire (c). Une simulation d'image HRTEM à partir du matériau virtuel obtenu permet de valider la qualité de la reconstruction (d). Nous présentons en détail cette méthode ainsi que la structure et les propriétés mécaniques calculées pour des pyrocarbones laminaires rugueux, tels que préparés et traités thermiquement

Governance:Governance Frameworks for Wastewater Management

MVZ specimen catalog numbers and views represented. (XLSX 495 kb

Investigating carbon materials nanostructure using image orientation statistics

International audienceA new characterization method of the lattice fringe images of turbostratic carbons is proposed. This method is based on the computation of their orientation field without explicit detection of fringes. It allows meaningful insights into the material nanostructure and nanotexture at several scales, either qualitatively or quantitatively. The calculation of pairwise spatial statistics of the orientation field at short distance provides measurements of the coherence lengths along any direction, in particular along and orthogonally to the layers. These statistics also allow representing orientation coherence patterns typical of the observed nanostructure. At larger distances, the mean disorientation of the fringes is computed and information about the homogeneity of the sample is obtained. An experimental validation is carried out on various artificial images and an application to the characterization of four bulk turbostratic carbons is provided

Improving multifrontal methods by means of block low-rank representations

Submitted for publication to SIAMMatrices coming from elliptic Partial Differential Equations (PDEs) have been shown to have a low-rank property: well defined off-diagonal blocks of their Schur complements can be approximated by low-rank products. Given a suitable ordering of the matrix which gives to the blocks a geometrical meaning, such approximations can be computed using an SVD or a rank-revealing QR factorization. The resulting representation offers a substantial reduction of the memory requirement and gives efficient ways to perform many of the basic dense algebra operations. Several strategies have been proposed to exploit this property. We propose a low-rank format called Block Low-Rank (BLR), and explain how it can be used to reduce the memory footprint and the complexity of direct solvers for sparse matrices based on the multifrontal method. We present experimental results that show how the BLR format delivers gains that are comparable to those obtained with hierarchical formats such as Hierarchical matrices (H matrices) and Hierarchically Semi-Separable (HSS matrices) but provides much greater flexibility and ease of use which are essential in the context of a general purpose, algebraic solver

Bats that walk: a new evolutionary hypothesis for the terrestrial behaviour of New Zealand's endemic mystacinids.

RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are.BACKGROUND: New Zealand's lesser short-tailed bat Mystacina tuberculata is one of only two of c.1100 extant bat species to use a true walking gait when manoeuvring on the ground (the other being the American common vampire bat Desmodus rotundus). Mystacina tuberculata is also the last surviving member of Mystacinidae, the only mammalian family endemic to New Zealand (NZ) and a member of the Gondwanan bat superfamily Noctilionoidea. The capacity for true quadrupedal terrestrial locomotion in Mystacina is a secondarily derived condition, reflected in numerous skeletal and muscular specializations absent in other extant bats. The lack of ground-based predatory native NZ mammals has been assumed to have facilitated the evolution of terrestrial locomotion and the unique burrowing behaviour of Mystacina, just as flightlessness has arisen independently many times in island birds. New postcranial remains of an early Miocene mystacinid from continental Australia, Icarops aenae, offer an opportunity to test this hypothesis. RESULTS: Several distinctive derived features of the distal humerus are shared by the extant Mystacina tuberculata and the early Miocene Australian mystacinid Icarops aenae. Study of the myology of M. tuberculata indicates that these features are functionally correlated with terrestrial locomotion in this bat. Their presence in I. aenae suggests that this extinct mystacinid was also adapted for terrestrial locomotion, despite the existence of numerous ground-based mammalian predators in Australia during the early Miocene. Thus, it appears that mystacinids were already terrestrially-adapted prior to their isolation in NZ. In combination with recent molecular divergence dates, the new postcranial material of I. aenae constrains the timing of the evolution of terrestrial locomotion in mystacinids to between 51 and 26 million years ago (Ma). CONCLUSION: Contrary to existing hypotheses, our data suggest that bats are not overwhelmingly absent from the ground because of competition from, or predation by, other mammals. Rather, selective advantage appears to be the primary evolutionary driving force behind habitual terrestriality in the rare bats that walk. Unlike for birds, there is currently no evidence that any bat has evolved a reduced capacity for flight as a result of isolation on islands