Enterprise model verification and validation : an approach

This article presents a verification and validation approach which is used here in order to complete the classical tool box the industrial user may utilize in enterprise modeling and integration domain. This approach, which has been defined independently from any application domain is based on several formal concepts and tools presented in this paper. These concepts are property concepts, property reference matrix, properties graphs, enterprise modeling domain ontology, conceptual graphs and formal reasoning mechanisms

Le tigrinya et le principe du contour obligatoire

Dans cet article, nous présentons une défense du statut universel du Principe de Contour Obligatoire (PCO). Une réanalyse des faits de spirantisation en tigrinya, qui avaient été considérés comme problématiques pour le PCO, est proposée. Nous montrons par ailleurs, sur la base de données nouvelles, qu’il existe des manifestations positives du PCO dans la grammaire du tigrinya. Nous suggérons que le PCO est universellement restreint au mot phonologique. La différence entre les faits cruciaux de l’hébreu biblique et ceux du tigrinya, qui était à l’origine du débat, n’est que le reflet d’une différence d’ordre morphologique. Notre analyse rend compte de tous les faits discutés antérieurement ainsi que de faits supplémentaires, qui restent sans explication pour les analyses concurrentes. Notre analyse a des conséquences pour la théorie phonologique en ce qu’elle permet une caractérisation plus restrictive de l’ensemble des grammaires accessibles à l’enfant.In this paper, we offer arguments in defence of the universal status of the Obligatory Contour Principle (OCP). We reanalyse the hitherto problematic facts of Tigrinya spirantization. We adduce, moreover, new evidence of positive manifestations of the OCP in the grammar of Tigrinya. It is claimed that the domain of validity of the OCP is the phonological word. Hence, the difference between the crucial facts of Biblical Hebrew and Tigrinya merely reflects a difference between the organization of strings of morphemes in both languages. Our analysis accounts for all the previously discussed facts as well as additional data which remain unexplained under competing analyses. This analysis allows for a more restrictive characterization of the set of grammars available to the language learner

Full-sky CMB lensing reconstruction in presence of sky-cuts

We consider the reconstruction of the CMB lensing potential and its power spectrum of the full sphere in presence of sky-cuts due to point sources and Galactic contaminations. Those two effects are treated separately. Small regions contaminated by point sources are filled in using Gaussian constrained realizations. The Galactic plane is simply masked using an apodized mask before lensing reconstruction. This algorithm recovers the power spectrum of the lensing potential with no significant bias.Comment: Submitted to A&

CMB Polarization can constrain cosmology better than CMB temperature

We demonstrate that for a cosmic variance limited experiment, CMB E polarization alone places stronger constraints on cosmological parameters than CMB temperature. For example, we show that EE can constrain parameters better than TT by up to a factor 2.8 when a multipole range of l=30-2500 is considered. We expose the physical effects at play behind this remarkable result and study how it depends on the multipole range included in the analysis. In most relevant cases, TE or EE surpass the TT based cosmological constraints. This result is important as the small scale astrophysical foregrounds are expected to have a much reduced impact on polarization, thus opening the possibility of building cleaner and more stringent constraints of the LCDM model. This is relevant specially for proposed future CMB satellite missions, such as CORE or PRISM, that are designed to be cosmic variance limited in polarization till very large multipoles. We perform the same analysis for a Planck-like experiment, and conclude that even in this case TE alone should determine the constraint on $\Omega_ch^2$ better than TT by 15%, while determining $\Omega_bh^2$, $n_s$ and $\theta$ with comparable accuracy. Finally, we explore a few classical extensions of the LCDM model and show again that CMB polarization alone provides more stringent constraints than CMB temperature in case of a cosmic variance limited experiment.Comment: 14 pages, 16 figure

Vérification de modèles de processus d’entreprise : une approche formelle.

Dans le cycle de vie de développement d’un système industriel, les phases de vérification et, si possible de validation, impactent notablement sur la qualité du système final c’est à dire son adéquation et sa pertinence vis-à-vis de ses objectifs cibles. Dans le domaine de la Modélisation d’Entreprise, il existe peu d’outils de vérification et/ou de validation basés sur d’autres approches que la simulation. Cet article présente une approche formelle pour la vérification des modèles de processus d’entreprise par preuve de propriétés. Cette démarche s’appuie tout d’abord sur la construction d’une ontologie du domaine concerné visant à définir rigoureusement le vocabulaire qui sera utilisé pendant les phases de vérification. Elle met ensuite en œuvre des mécanismes de traduction et de raisonnement utilisant les graphes conceptuels qui s’avèrent aisés à manipuler dans un milieu industriel. Une mise en œuvre de la démarche de vérification proprement dite est enfin proposée afin de démontrer l’intérêt de ce type d’approche dans le domaine

Bayesian model comparison in cosmology with Population Monte Carlo

We use Bayesian model selection techniques to test extensions of the standard flat LambdaCDM paradigm. Dark-energy and curvature scenarios, and primordial perturbation models are considered. To that end, we calculate the Bayesian evidence in favour of each model using Population Monte Carlo (PMC), a new adaptive sampling technique which was recently applied in a cosmological context. The Bayesian evidence is immediately available from the PMC sample used for parameter estimation without further computational effort, and it comes with an associated error evaluation. Besides, it provides an unbiased estimator of the evidence after any fixed number of iterations and it is naturally parallelizable, in contrast with MCMC and nested sampling methods. By comparison with analytical predictions for simulated data, we show that our results obtained with PMC are reliable and robust. The variability in the evidence evaluation and the stability for various cases are estimated both from simulations and from data. For the cases we consider, the log-evidence is calculated with a precision of better than 0.08. Using a combined set of recent CMB, SNIa and BAO data, we find inconclusive evidence between flat LambdaCDM and simple dark-energy models. A curved Universe is moderately to strongly disfavoured with respect to a flat cosmology. Using physically well-motivated priors within the slow-roll approximation of inflation, we find a weak preference for a running spectral index. A Harrison-Zel'dovich spectrum is weakly disfavoured. With the current data, tensor modes are not detected; the large prior volume on the tensor-to-scalar ratio r results in moderate evidence in favour of r=0. [Abridged]Comment: 11 pages, 6 figures. Matches version accepted for publication by MNRA

Estimation of cosmological parameters using adaptive importance sampling

We present a Bayesian sampling algorithm called adaptive importance sampling or Population Monte Carlo (PMC), whose computational workload is easily parallelizable and thus has the potential to considerably reduce the wall-clock time required for sampling, along with providing other benefits. To assess the performance of the approach for cosmological problems, we use simulated and actual data consisting of CMB anisotropies, supernovae of type Ia, and weak cosmological lensing, and provide a comparison of results to those obtained using state-of-the-art Markov Chain Monte Carlo (MCMC). For both types of data sets, we find comparable parameter estimates for PMC and MCMC, with the advantage of a significantly lower computational time for PMC. In the case of WMAP5 data, for example, the wall-clock time reduces from several days for MCMC to a few hours using PMC on a cluster of processors. Other benefits of the PMC approach, along with potential difficulties in using the approach, are analysed and discussed.Comment: 17 pages, 11 figure

Generation and analysis of a 29,745 unique Expressed Sequence Tags from the Pacific oyster (Crassostrea gigas) assembled into a publicly accessible database: the GigasDatabase

Background: Although bivalves are among the most-studied marine organisms because of their ecological role and economic importance, very little information is available on the genome sequences of oyster species. This report documents three large-scale cDNA sequencing projects for the Pacific oyster Crassostrea gigas initiated to provide a large number of expressed sequence tags that were subsequently compiled in a publicly accessible database. This resource allowed for the identification of a large number of transcripts and provides valuable information for ongoing investigations of tissue-specific and stimulus-dependant gene expression patterns. These data are crucial for constructing comprehensive DNA microarrays, identifying single nucleotide polymorphisms and microsatellites in coding regions, and for identifying genes when the entire genome sequence of C. gigas becomes available. Description: In the present paper, we report the production of 40,845 high-quality ESTs that identify 29,745 unique transcribed sequences consisting of 7,940 contigs and 21,805 singletons. All of these new sequences, together with existing public sequence data, have been compiled into a publicly-available Website http://public-contigbrowser.sigenae.org:9090/Crassostrea_gigas/index.htm l. Approximately 43% of the unique ESTs had significant matches against the SwissProt database and 27% were annotated using Gene Ontology terms. In addition, we identified a total of 208 in silico microsatellites from the ESTs, with 173 having sufficient flanking sequence for primer design. We also identified a total of 7,530 putative in silico, single-nucleotide polymorphisms using existing and newly-generated EST resources for the Pacific oyster. Conclusion: A publicly-available database has been populated with 29,745 unique sequences for the Pacific oyster Crassostrea gigas. The database provides many tools to search cleaned and assembled ESTs. The user may input and submit several filters, such as protein or nucleotide hits, to select and download relevant elements. This database constitutes one of the most developed genomic resources accessible among Lophotrochozoans, an orphan clade of bilateral animals. These data will accelerate the development of both genomics and genetics in a commercially-important species with the highest annual, commercial production of any aquatic organism