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KINETIC FUNCTIONS IN MAGNETOHYDRODYNAMICS WITH RESISTIVITY AND HALL EFFECT

Acta Mathematica Scientia 2009年第6期29卷 1684-1702页

作者： philippe G. Le Siddhartha Mishra FlochLaboratoire Jacques-Louis Lions Centre National de la Recherche ScientifiqueUniversit Pierre et Marie Curie (Paris 6) 4 Place Jussieu 75258 Paris France Seminar for Applied Mathematics D-Math ETH HG Raemistrasse Zürich-8092 Switzerland

We consider a nonlinear hyperbolic system of two conservation laws which arises in ideal magnetohydrodynamics and includes second-order terms accounting for magnetic resistivity and Hall effect. We show that the initial value problem for this model may lead to solutions exhibiting complex wave structures, including undercompressive nonclassical shock waves. We investigate numerically the subtle competition that takes place between the hyperbolic, diffusive, and dispersive parts of the system. Following Abeyratne, Knowles, LeFloch, and Truskinovsky, who studied similar questions arising in fluid and solid flows, we determine the associated kinetic function which characterizes the dynamics of undereompressive shocks driven by resistivity and Hall effect. To this end, we design a new class of ＂schemes with eontroled dissipation＂, following recent work by LeFloch and Mohammadian. It is now recognized that the equivalent equation associated with a scheme provides a guideline to design schemes that capture physically relevant, nonclassical shocks. We propose a new class of schemes based on high-order entropy conservative, finite differences for the hyperbolic flux, and high-order central differences for the resistivity and Hall terms. These schemes are tested for several regimes of （co-planar or not） initial data and parameter values, and allow us to analyze the properties of nonclassical shocks and establish the existence of monotone kinetic functions in magnetohydrodynamics.

关键词： hyperbolic conservation law magnetohydrodynamics magnetic resistivity Hall effect undercompressive shock kinetic function

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Conceptual design and implementation of spatial data warehouses integrating regular grids of points

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International Journal of Digital Earth 2017年第9期10卷 901-922页

作者： Sandro Bimonte Mehdi Zaamoune philippe Beaune Technologies and information systems for agricultural systems Departement Institut national de recherche en sciences et technologies pour l’environnement et l’agricultureAubiereFrance Agaetis Clermont-FerrandFrance

Spatial online analytical processing(OLAP)and spatial data warehouse(SDW)systems are geo-business intelligence technologies that enable the analysis of huge volumes of geographic *** the last decade,the conceptual design and implementation of SDWs that integrate spatial data,which are represented using the vector model,have been extensively ***,the integration of field data(a continuous representation of spatial data)in SDWs is a recent unresolved research *** SDWs with field data improves the spatio-multidimensional analysis capabilities with continuity and *** by the need for a conceptual design tool and relational online analytical processing(ROLAP)implementation,we propose a UML profile for SDWs that integrates a regular grid of points and supports continuity and *** also propose an efficient implementation of a ROLAP architecture.

关键词： Geoinformatics spatial OLAP geospatial data integration spatial data infrastructure

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Radical-mediated hydroalkylation of 2-vinylpyrrolidine derivatives: a versatile entry into indolizidine alkaloids

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Science China Chemistry 2019年第11期62卷 1504-1506页

作者： Sankar Rao Suravarapu Bettina Peter philippe Renaud Department of Chemistry and Biochemistry University of Bern

A concise route for the preparation of two simple optically pure indolizidin-5-ones has been *** key chain elongation process was achieved using a triethylborane/catechol mediated hydroalkylation of Boc-protected *** using complementary strategies,these two bicyclic lactams can be alkylated with complete control of the stereochemistry at C(5)and their conversion to a variety of indolizidine alkaloids such as coniceine,indolizidine 209D and 167B,5-epi-indolizidine 249A and monomorine has been reported in the literature.

关键词： alkenes carbohydrogenation radical reaction catechol triethylborane α-iodoesters allylamine

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Machine learning applied to road safety modeling:A systematic literature review

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Journal of Traffic and Transportation Engineering(English Edition) 2020年第6期7卷 775-790页

作者： philippe Barbosa Silva Michelle Andrade Sara Ferreira Department of Civil Engineering Goiano Federal Institute-Rio Verde CampusRio Verde 75901-970Brazil Department of Civil and Environmental Engineering University of BrasiliaBrasilia 70910-900Brazil Research Centre for Territory Transports and EnvironmentUniversity of PortoPorto 4200-465Portugal

Road safety modeling is a valuable strategy for promoting safe mobility,enabling the development of crash prediction models(CPM)and the investigation of factors contributing to crash *** modeling has traditionally used statistical techniques despite acknowledging the limitations of this kind of approach(specific assumptions and prior definition of the link functions),which provides an opportunity to explore alternatives such as the use of machine learning(ML)*** study reviews papers that used ML techniques for the development of CPM.A systematic literature review protocol was conducted,that resulted in the analysis of papers and their *** types of models were identified:crash frequency,crash classification by severity,and crash frequency and *** first is a regression problem,the second,a classificatory one and the third can be approached either as a combination of the preceding two or as a regression model for the expected number of crashes by severity *** main groups of techniques used for these purposes are nearest neighbor classification,decision trees,evolutionary algorithms,support-vector machine,and artificial neural *** last one is used in many kinds of approaches given the ability to deal with both regression and classification problems,and also multivariate response *** paper also presents the main performance metrics used to evaluate the models and compares the results,showing the clear superiority of the ML-based models over the statistical *** addition,it identifies the main explanatory variables used in the models,which shows the predominance of road-environmental aspects as the most important factors contributing to crash *** review fulfilled its objective,identifying the various approaches and the main research characteristics,limitations,and opportunities,and also highlighting the potential of the usage of ML in crash analyses.

关键词： Transportation engineering Road safety modeling Crash prediction Crash injury severity Machine learning Systematic literature review

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Using experimental data to reduce the single-building sigma of fragility curves:case study of the BRD tower in Bucharest,Romania

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Earthquake Engineering and Engineering Vibration 2013年第4期12卷 643-658页

作者： Matthieu Perrault philippe Gueguen Alexandru Aldea Sorin Demetriu Institut des Sciences de la Terre Université Joseph Fourier Grenoble ICNRS/IFSTTAR Technical University of Civil Engineering

The lack of knowledge concerning modelling existing buildings leads to significant variability in fragility curves for single or grouped existing buildings. This study aims to investigate the uncertainties of fragility curves, with special consideration of the single-building sigma. Experimental data and simplified models are applied to the BRD tower in Bucharest, Romania, a RC building with permanent instrumentation. A three-step methodology is applied：（1） adjustment of a linear MDOF model for experimental modal analysis using a Timoshenko beam model and based on Anderson＇s criteria, （2） computation of the structure＇s response to a large set of accelerograms simulated by SIMQKE software, considering twelve ground motion parameters as intensity measurements （IM）, and （3） construction of the fragility curves by comparing numerical interstory drift with the threshold criteria provided by the Hazus methodology for the slight damage state. By introducing experimental data into the model, uncertainty is reduced to 0.02 considering Sd ） as seismic intensity IM and uncertainty related to the model is assessed at 0.03. These values must be compared with the total uncertainty value of around 0.7 provided by the Hazus methodology.

关键词： vulnerability fragility curves uncertainty slight damage Timoshenko model Bucharest

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SECOND-ORDER CONVERGENCE PROPERTIES OF TRUST-REGION METHODS USING INCOMPLETE CURVATURE INFORMATION, WITH AN APPLICATION TO MULTIGRID OPTIMIZATION

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Journal of Computational Mathematics 2006年第6期24卷 676-692页

作者： Serge Gratton Annick Sartenaer philippe L. Toint CERFACS av. G. Coriolis Toulouse France Department of Mathematics University of Namur 61 rue de Bruxelles B-5000 Namur Belgium

Convergence properties of trust-region methods for unconstrained nonconvex optimization is considered in the case where information on the objective function＇s local curvature is incomplete, in the sense that it may be restricted to a fixed set of ＂test directions＂ and may not be available at every iteration. It is shown that convergence to local ＂weak＂ minimizers can still be obtained under some additional but algorithmically realistic conditions. These theoretical results are then applied to recursive multigrid trust-region methods, which suggests a new class of algorithms with guaranteed second-order convergence properties.

关键词： Nonlinear optimization Convergence to local minimizers Multilevel problems.

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Identification of biomarkers of human pancreatic adenocarcinomas by expression profiling and validation with gene expression analysis in endoscopic ultrasound-guided fine needle aspiration samples

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World Journal of Gastroenterology 2006年第21期12卷 3344-3351页

作者： Henrik Laurell Michèle Bouisson philippe Berthelémy philippe Rochaix Sébastien Déjean philippe Besse Christiana Susini Lucien Pradayrol Nicole Vaysse Louis Buscail INSERM U531 IFR31 Institut Louis BugnardBP 8422531432 Toulouse Cedex 4France Service de Gastroentérologie Centre Hospitaller de Pau PauFrance Laboratoire d'Anatomo-Pathologie Institut Claudius Regaud ToulouseFrance Laboratoire de Statistique et Probabilités Université Paul Sabatier ToulouseFrance INSERM U531 IFR31 Institut Louis BugnardBP 8422531432 Toulouse Cedex 4France Service de Gastroenterologie et de la NutritionCHU RangueilToulouseFrance

AIM： To compare gene expression profiles of pancreatic adenocarcinoma tissue specimens, human pancreatic and colon adenocarcinoma and leukemia cell lines and normal pancreas samples in order to distinguish differentially expressed genes and to validate the differential expression of a subset of genes by quantitative real-time RT-PCR （RT-QPCR） in endoscopic ultrasound-guided fine needle aspiration （EUS-guided FNA） ***： Commercially dedicated cancer cDNA macroarrays （Atlas Human Cancer 1.2） containing 1176 genes were used. Different statistical approaches （hierarchical clustering, principal component analysis （PCA） and SAM） were used to analyze the expression data. RT-QPCR and immunohistochemical studies were used for validation of ***： RT-QPCR validated the increased expression of LCN2 （lipocalin 2） and for the first time PLAT （tissue-type plasminogen activator or tPA） in malignant pancreas as compared with normal pancreas. Immunohistochemical analysis confirmed the increased expression of LCN2 protein localized in epithelial cells of ducts invaded by carcinoma. The analysis of PLAT and LCN2 transcripts in 12 samples obtained through EUS-guided FNA from patients with pancreatic adenocarcinoma showed significantly increased expression levels in comparison with those found in normal tissues, indicating that a sufficient amount of high quality RNA can be obtained with this ***： Expression profiling is a useful method to identify biomarkers and potential target genes. Molecular analysis of EUS-guided FNA samples in pancreatic cancer appears as a valuable strategy for the diagnosis of pancreatic adenocarcinomas.

关键词： Pancreas Colon Adenocarcinoma Gene expression profiling Endoscopic ultrasonography Ultrasound Fine needle aspiration

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CURDIS:A template for incremental curve discretization algorithms and its application to conics

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虚拟现实与智能硬件（中英文） 2024年第5期6卷 358-382页

作者： philippe LATOUR Marc VAN DROOGENBROECK Montefiore Institute University of LiègeQuartier Polytech 1Allée de la découverte 104000 LiègeBelgium

We introduce CURDIS,a template for algorithms to discretize arcs of regular curves by incrementally producing a list of support pixels covering the *** this template,algorithms proceed by finding the tangent quadrant at each point of the arc and determining which side the curve exits the pixel according to a tailored *** two elements can be adapted for any type of curve,leading to algorithms dedicated to the shape of specific *** the calculation of the tangent quadrant for various curves,such as lines,conics,or cubics,is simple,it is more complex to analyze how pixels are traversed by the *** the case of conic arcs,we found a criterion for determining the pixel exit *** leads us to present a new algorithm,called CURDIS-C,specific to the discretization of conics,for which we provide all the ***,the criterion for conics requires between one and three sign tests and four additions per pixel,making the algorithm efficient for resource-constrained systems and feasible for fixed-point or integer arithmetic *** algorithm also perfectly handles the pathological cases in which the conic intersects a pixel twice or changes quadrants multiple times within this pixel,achieving this generality at the cost of potentially computing up to two square roots per *** illustrate the use of CURDIS for the discretization of different curves,such as ellipses,hyperbolas,and parabolas,even when they degenerate into lines or corners.

关键词： Computer graphics Curve discretization Conics Rasterization Ellipse drawing Conic spline Conic pencil

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Redox and acetylation coordinate ABA-independent osmotic stress response

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Molecular Plant 2022年第4期15卷 583-585页

作者： Christophe Belin Jean-philippe Reichheld Laboratoire Génome et Développement des Plantes UniversitéPerpignan Via Domitia66860 PerpignanFrance Laboratoire Génome et Développement des Plantes CNRS66860 PerpignanFrance

Osmotic stress caused by drought or high salt concentrations is a major threat that limits plant development and affect crop *** the context of climate change,understanding the mechanisms by which plants perceive their environment to adapt to their development is a major question.A common feature of plants being exposed to osmotic stress is the accumulation of excessive reactive oxygen species(ROS)(Martinière et al.,2019).ROS can oxidatively damage biological molecules,such as nucleic acids,proteins,and lipids,but also play important signaling *** protect from ROS-induced oxidation,living organisms have developed a large panel of enzymatic and non-enzymatic systems to remove ROS and oxidized molecules.

关键词： functions. enzymatic coordinate

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Multiscale Hybrid-Mixed Finite Element Method for Flow Simulation in Fractured Porous Media

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Computer Modeling in Engineering & Sciences 2019年第4期119卷 145-163页

作者： philippe Devloo Wenchao Teng Chen-Song Zhang FEC Universidade Estadual de CampinasBrazil Tracy Energy Technologies BeijingChina NCMIS&LSEC Academy of Mathematics and System SciencesCASBeijingChina

The multiscale hybrid-mixed(MHM)method is applied to the numerical approximation of two-dimensional matrix fluid flow in porous media with *** two-dimensional fluid flow in the reservoir and the one-dimensional flow in the discrete fractures are approximated using mixed finite *** coupling of the two-dimensional matrix flow with the one-dimensional fracture flow is enforced using the pressure of the one-dimensional flow as a Lagrange multiplier to express the conservation of fluid transfer between the fracture flow and the divergence of the one-dimensional fracture flux.A zero-dimensional pressure(point element)is used to express conservation of mass where fractures *** issuing simulation is then reduced using the MHM method leading to accurate results with a very reduced number of global equations.A general system was developed where fracture geometries and conductivities are specified in an input file and meshes are generated using the public domain mesh generator *** test cases illustrate the effectiveness of the proposed approach by comparing the multiscale results with direct simulations.

关键词： Fracture simulation discrete fracture model multiscale hybrid finite element mixed formulation

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