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In this work, we have evaluated the performances of a custom-built OFCEAS instrumentation for the determination of the composition of energy gases, focusing on methane and carbon dioxide as main components and carbon monoxide as impurities, in comparison with the well-established, validated, and traceable gas chromatographic method. A total of 115 real sample gases collected in biogas plants or landfills were analyzed using with both techniques over a period of 12 months. The comparison of the technique showed that the virtual modeling which allows the measurement, needs to be optimized using real samples of varied compositions. The OFCEAS measurement technique was found to be capable of measuring both the main components and a trace component in different matrices; to within a 2% measurement uncertainty (higher than the GC/TCD method). The OFCEAS method exhibits a very fast response, does not require daily calibration, and can be implemented online. The agreements between the OFCEAS technique and the GC/TCD method show that the drift of the OFCEAS instruments remains acceptable in the long term as long as no change is made to the virtual modeling. Matrix effects were observed, and those need to be taken into consideration when analyzing different types of samples.

This paper addresses the modelling of cesium sorption in non-equilibrium and nonlinear conditions with a two-site model. Compared to the classical K

Sunday, day of rest in a pavilion of Seine-Saint-Denis in this so particular period of confinement because of the coronavirus disease 2019. Time seems to stand still. A healthcare executive shares his experiences at the "Les 4 Saisons" accommodation facility for dependent elderly, located in Bagnolet.

Sorption hypotheses and models are required for the prediction of

Sunday, day of rest in a pavilion of Seine-Saint-Denis in this so particular period of confinement because of the coronavirus disease 2019. Time seems to stand still. A healthcare executive shares his experiences at the "Les 4 Saisons" accommodation facility for dependent elderly, located in Bagnolet.

This study aimed at reconstructing the dynamics of radiocesium (134Cs, 137Cs) fluxes exported at the outlet of catchments impacted by the Fukushima Dai-ichi Nuclear Power Plant accident. River flowrate, load and dissolved/particulate radiocesium concentrations were simultaneously monitored during the period 2012-2016 in 4 coastal forested catchments of Uda (0.3, 97 km2), Mano (20 km2) and Ohta rivers (43 km2). Precipitation time series were derived from raingauges (JMA) and different satellite datasets (AMeDAS, GSmap, Aphrodite). Contamination maps were derived from MEXT airborne monitoring surveys (MEXT/JAEA). A class of stochastic models adapted from Mass Response Functions (originally introduced by Rinaldo & Marani, 1987), was implemented to reconstruct radiocesium fluxes. This theory, describing the coupled transport of water and contaminant particles with transit/holding time distributions, was proposed non only because it encompasses the classical assessment models, but also because it allows some improvements with other hypotheses about the catchment response, notably: transit time distribution of effective rainfall, exchanges between mobile and immobile phases (mass transfer rate, equilibrium concentration) and the macroscopic mass balance at the basin scale.Classic hypotheses about the catchment response (corresponding to variants of removal coefficients and transfer function models) were tested by Bayesian inference. Inferences were conducted with routines provided by the R environment (R Development Core Team, 2013) and the package BayesianTools (Hartig et al., 2018). The oversampling of extreme events in the monitoring design was counterbalanced by assigning weights to the observations corresponding to the likelihood of the carrier flow rate (liquid or solid flow rate).For catchments of Mano (43.64 km2) and Ohta (20.28 km2) rivers, observations covered both low-flow and high-flow periods. The short-term fluctuations of the wash-off catchment response were strongly transport-limited: dissolved 137Cs fluxes varied linearly with river flow rate (m3/s), whereas particulate 137Cs fluxes varied linearly with solid flow rate (kg/s) or nonlinearly with river flow rate (m3/s). The longer-term decline of radionuclide availability to wash-off was credible for dissolved wash-off, but was not plausible for solid wash-off, certainly due to the short period of observations of the monitorings. For assessment purposes, the removal coefficient approach appeared as a good option for both dissolved and particulate 137Cs wash-off. For Mano and Ohta catchments, median model predictions agreed with observations within a factor ranging from 1.47 to 1.66 for dissolved wash-off, and from 19.22 to 22.44 for particulate wash-off. The explicative power of the proposed models will need to be updated when more recent measurements are available and their predictive power needs to be confirmed on independent observations on other catchments.

International audience; The paper deals with base revision for Answer Set Programming (ASP). Base revision in classical logic is done by the removal of formulas. Exploiting the non-monotonicity of ASP allows one to propose other revision strategies, namely addition strategy or removal and/or addition strategy. These strategies allow one to define families of rule-based revision operators. The paper presents a semantic characterization of these families of revision operators in terms of answer sets. This semantic characterization allows for equivalently considering the evolution of syntactic logic programs and the evolution of their semantic content. It then studies the logical properties of the proposed operators and gives complexity results.

International audience; This paper deals with querying ontology-based knowledge bases equipped with non-monotonic rules through a case study within the framework of Cultural Heritage. It focuses on 3D underwater surveys on the Xlendi wreck which is represented by an OWL2 knowledge base with a large dataset. The paper aims at improving the interactions between the archaeologists and the knowledge base providing new queries that involve non-monotonic rules in order to perform qualitative spatial reasoning. To this end, the knowledge base initially represented in OWL2-QL is translated into an equivalent Answer Set Programming (ASP) program and is enriched with a set of non-monotonic ASP rules suitable to express default and exceptions. An ASP query answering approach is proposed and implemented. Furthermore due to the increased expressiveness of non-monotonic rules it provides spatial reasoning and spatial relations between artifacts query answering which is not possible with query answering languages such as SPARQL and SQWRL.

The natural way to use Answer Set Programming (ASP) to represent knowledge in Artificial Intelligence or to solve a combinatorial problem is to elaborate a first-order logic program with default negation. In a preliminary step, this program with variables is translated in an equivalent propositional one by a first tool: the grounder. Then, the propositional program is given to a second tool: the solver. This last one computes (if they exist) one or many answer sets (stable models) of the program, each answer set encoding one solution of the initial problem. Until today, almost all ASP systems apply this two steps computation. In this article, the projectASPeRiX. is presented as a first-order forward chaining approach for Answer Set Computing. This project was among the first to introduce an approach of answer set computing that escapes the preliminary phase of rule instantiation by integrating it in the search process. The methodology applies a forward chaining of first-order rules that are grounded on the fly by means of previously produced atoms. Theoretical foundations of the approach are presented, the main algorithms of the ASP solverASPeRiX. are detailed and some experiments and comparisons with existing systems are provided.

International audience; Belief base revision has been studied within the answer set programming framework. We go a step further by introducing uncertainty and studying belief base revision when beliefs are represented by possibilistic logic programs under possibilistic answer set semantics and revised by certain input. The paper proposes two approaches of rule-based revision operators and presents their semantic characterization in terms of possibilistic distribution. This semantic characterization allows for equivalently considering the evolution of syntactic logic programs and the evolution of their semantic content. It then studies the logical properties of the proposed operators and gives complexity results.

International audience; This article deals with the combination of ontologies and rules by means of existential rules and answer set programming. Existential rules have been proposed for representing ontological knowledge, specifically in the context of Ontology- Based Data Access. Furthermore Answer Set Programming (ASP) is an appropriate formalism to represent various problems issued from Artificial Intelligence and arising when available information is incomplete. The combination of the two formalisms requires to extend existential rules with nonmonotonic negation and to extend ASP with existential variables. In this article, we present the syntax and semantics of Existential Non Monotonic Rules (ENM-rules) using skolemization which join together the two frameworks. We formalize its links with standard ASP. Moreover, since entailment with existential rules is undecidable, we present conditions that ensure the termination of a breadth-first forward chaining algorithm known as the chase and we discuss extension of these results in the nonmonotonic case.