Search results for "Tree"

showing 10 items of 1841 documents

Geo-Epidemiology of Age-Related Macular Degeneration: New Clues Into the Pathogenesis

2015

Abstract PURPOSE: To evaluate the demographic, geographic, and race-related variables that account for geographic variability in prevalence rates of age-related macular degeneration (AMD). DESIGN: Systematic review, meta-regression, and decision-tree analysis. METHODS: A systematic literature review of PubMed, Medline, Web of Science, and Embase databases identified population-based studies on the prevalence of AMD published before May 2014. Only population-based studies that took place in a spatially explicit geographic area that could be geolocalized, and used retinal photographs and standardized grading classifications, were included. Latitude and longitude data (geolocalization) and the…

Malemedicine.medical_specialtygenetic structuresPopulationPrevalenceGlobal HealthPrevalence of AMDLatitude03 medical and health sciencesMacular Degeneration0302 clinical medicineAge DistributionRisk FactorsEpidemiologymedicinePrevalenceHumans030212 general & internal medicineSex DistributioneducationAgedAged 80 and overeducation.field_of_studyGeoepidemiologyGeographySettore MED/30 - Malattie Apparato VisivoDecision TreesRegression analysisBayes TheoremMiddle Agedeye diseasesOphthalmologyGeographySystematic reviewAge-Related Macular DegenerationMeta-analysis030221 ophthalmology & optometryFemalesense organsLongitudeDemography
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Evolution of a Quantum System: Lifetime of a Determinant

1976

A measure of the ''dependency'' of a many-particle system is defined and its time dependence is evaluated for systems initially described by a single Slater determinant. An uncertainty product between the energy spread of the initial determinant and the lifetime of a system's independence is established. Numerical estimates of some lifetimes are given. They are not so long as to be reassuring for nuclear time-dependent Hartree--Fock calculations. Each separate case ought to be checked. 1 table.

Many-body problemPhysicsUncertainty principleQuantum mechanicsProduct (mathematics)Quantum systemHartree–Fock methodGeneral Physics and AstronomySlater determinantStatistical physicsWave functionMeasure (mathematics)Physical Review Letters
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A Short Presentation of LucSim

2017

LucSim is a cellular automata (CA) dedicated to geographical analysis and spatial simulation for researchers and advanced planning institutes, providing user-friendly software in order to analyze and simulate land use changes and dynamics. Two complementary models are integrated in the CA: (1) a Markov Chain used to calculate transition matrices from a date to another, and (2) a Decision Tree able to automatically determine a set of transition rules to be applied on land use data. LucSim includes GIS compatibility functions allowing to display ESRI shapefiles and is based on raster georeferenced images saved in TIF format. It was mostly applied on French urban case studies.

Markov chainLand useComputer sciencebusiness.industryDecision treeShapefilecomputer.file_formatcomputer.software_genreCellular automatonSoftwareUrban planningData miningRaster graphicsbusinesscomputer
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Robust Assembly Assistance Using Informed Tree Search with Markov Chains

2022

Manual work accounts for one of the largest workgroups in the European manufacturing sector, and improving the training capacity, quality, and speed brings significant competitive benefits to companies. In this context, this paper presents an informed tree search on top of a Markov chain that suggests possible next assembly steps as a key component of an innovative assembly training station for manual operations. The goal of the next step suggestions is to provide support to inexperienced workers or to assist experienced workers by providing choices for the next assembly step in an automated manner without the involvement of a human trainer on site. Data stemming from 179 experiment partici…

Markov chainsChemical technologytraining stationsTP1-1185predictionIndustry 4.0artificial intelligenceBiochemistryArticleAtomic and Molecular Physics and OpticsAnalytical ChemistryA* algorithmassembly assistance systems; training stations; smart manufacturing; Industry 4.0; digital transformation; informed tree search; A* algorithm; Markov chains; prediction; artificial intelligenceinformed tree searchHumansdigital transformationassembly assistance systemssmart manufacturingElectrical and Electronic EngineeringInstrumentationAlgorithmsSensors; Volume 22; Issue 2; Pages: 495
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Improved Skyrme forces for Hartree-Fock seniority calculations

1992

Abstract The relationship between Skyrme parameters and physical quantities in nuclear matter is discussed in detail and bounds for some parameters are derived. Improved density-dependent two-body Skyrme forces are obtained by a least-squares fit of all the parameters simultaneously to a large set of data, including nuclear matter, mass formula and Landau parameters, and data of finite nuclei. Special attention is paid to the pairing properties of the interaction. These forces are used to perform self-consistent calculations in spherical closed-shell nuclei and Ca open-shell isotopes, within the Hartree-Fock seniority method. Good agreement with experimental data is obtained.

Mass formulaPhysicsNuclear physicsNuclear and High Energy PhysicsSeniority (financial)Quantum electrodynamicsPairingNuclear TheoryHartree–Fock methodNuclear matterPhysical quantityNuclear Physics A
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A new minimum spanning tree-based method for shape description and matching working in Discrete Cosine space

2009

In this article, a new minimum spanning tree-based method for shape description and matching is proposed. Its properties are checked through the problem of graphical symbols recognition. Recognition invariance in front shift and multi-oriented noisy objects was studied in the context of small and low resolution binary images. The approach seems to have many desirable properties, even if the construction of graphs induces an expensive algorithmic cost. In order to reduce time computing, an alternative solution based on image compression concepts is provided. The recognition is realized in a compact space, namely the Discrete Cosine space. The use of block discrete cosine transform is discuss…

Matching (graph theory)business.industryBinary imageFeature extraction020206 networking & telecommunicationsPattern recognition02 engineering and technologyMinimum spanning treeArtificial IntelligenceRobustness (computer science)0202 electrical engineering electronic engineering information engineeringDiscrete cosine transform020201 artificial intelligence & image processingComputer Vision and Pattern RecognitionArtificial intelligencebusinessSoftwareTransform codingComputingMilieux_MISCELLANEOUSMathematicsImage compression
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Pressure stability field of Mg-perovskite under deep mantle conditions: A topological approach based on Bader's analysis coupled with catastrophe the…

2019

Abstract The pressure stability field of the Mg-perovskite phase was investigated by characterizing the evolution of the electron arrangement in the crystal. Ab initio calculations of the perovskite structures in the range 0–185 GPa were performed at the HF/DFT (Hartree-Fock/Density Functional Theory) exchange–correlation terms level. The electron densities, calculated throughout the ab-initio wave functions, were analysed by means of the Bader's theory, coupled with Thom's catastrophe theory. To the best of our knowledge the approach is used for the first time. The topological results show the occurrence of two topological anomalies at P~20 GPa and P~110 GPa which delineate the pressure ra…

Materials Chemistry2506 Metals and AlloysMaterials scienceBader analysisAb initioSurfaces Coatings and FilmCritical pointsCeramics and Composite02 engineering and technologyElectronD’’ regionPerovskiteTopology01 natural sciencesCritical pointPhysics::GeophysicsFock spaceCoatings and FilmsCondensed Matter::Materials ScienceAb initio quantum chemistry methods0103 physical sciencesElectronicMaterials ChemistryOptical and Magnetic MaterialsAb initio; Bader analysis; Catastrophe theory; Critical points; Deep mantle; D’’ region; HF/DFT; High pressure; Perovskite; Topological analysis; Electronic Optical and Magnetic Materials; Ceramics and Composites; Process Chemistry and Technology; Surfaces Coatings and Films; Materials Chemistry2506 Metals and AlloysWave function010302 applied physicsCatastrophe theoryElectronic Optical and Magnetic MaterialProcess Chemistry and TechnologyHartree021001 nanoscience & nanotechnologyHF/DFTSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialsSurfacesTopological analysiHigh pressureAb initioCeramics and CompositesDensity functional theoryDeep mantleCatastrophe theory0210 nano-technologyTopological analysisBader analysiCeramics International
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Oil whip-induced wear in journal bearings

2014

Published version of an article in the journal: International Journal of Advanced Manufacturing Technology. Also available from the publisher at: http://dx.doi.org/10.1007/s00170-014-5805-8 This paper investigates the effect of oil whirl and oil whip in fluid film radial bearings due to possible metallic contact. The degree of metallic contact and thereby wear and tear between rotating shafts and bearing bushes is assessed by measuring electric currents through the oil film. The current as well as the voltage varied in accordance with the contact ratio between the shaft and bush in the fluid film radial bearing. The gauge signal thus indicates the degree of metallic contact based on the thi…

Materials scienceBearing (mechanical)Wear and tearMechanical Engineeringoil whipComputer Science Applications1707 Computer Vision and Pattern RecognitionIndustrial and Manufacturing Engineeringoil whirlComputer Science Applicationslaw.inventionFluid film radial bearings; Oil whip; Oil whirl; Industrial and Manufacturing Engineering; Control and Systems Engineering; Computer Science Applications1707 Computer Vision and Pattern Recognition; Software; Mechanical EngineeringControl and Systems EngineeringlawOil filmfluid film radial bearingsHigh loadGeotechnical engineeringVDP::Technology: 500::Materials science and engineering: 520Current (fluid)Whip (tree)SoftwareVoltageThe International Journal of Advanced Manufacturing Technology
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Comparative Hybrid Hartree-Fock-DFT Calculations of ReO3, SrTiO3, BaTiO3, PbTiO3 and CaTiO3 (001) Surfaces

2021

Materials scienceControl and Systems EngineeringQuantum mechanicsMaterials ChemistryCeramics and CompositesHartree–Fock methodElectrical and Electronic EngineeringCondensed Matter PhysicsElectronic Optical and Magnetic MaterialsIntegrated Ferroelectrics
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Ab initiocalculations of theFcenters in MgF2bulk and on the (001) surface

2012

We present and discuss the results of atomic and electronic structure calculations of the F centers in MgF2 bulk and on the (001) surface. The calculations are based on the B3PW Hartree–Fock and density functional theory hybrid exchange-correlation functional. Most of the electronic density of a missing fluorine ion is localized in the bulk vacancy and a little bit less—in a surface vacancy. It is shown that the electronic F center is a deep donor. The lattice distortion and defect formation energy on the neutral (001) surface and in the bulk are also compared.

Materials scienceHartree–Fock methodElectronic structureCondensed Matter PhysicsCrystallographic defectAtomic and Molecular Physics and OpticsIonAb initio quantum chemistry methodsVacancy defectPhysics::Atomic and Molecular ClustersDensity functional theoryAtomic physicsMathematical PhysicsElectronic densityPhysica Scripta
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