Sökning: "Lumping"

Visar resultat 1 - 5 av 16 avhandlingar innehållade ordet Lumping.

  1. 1. Inference of Hierarchical Structure in Complex Systems

    Författare :Olof Görnerup; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Protein evolution; Substitution groups; Modularity; Hierarchical dynamics; RNA world; Genetic code; Aggregation; Primordial evolution; Molecular evolution; Model reduction; Self-organization; Lumping; Emergence; Coarse graining;

    Sammanfattning : Hierarchical organization is a central property of complex systems. It is even argued that a system is required to be hierarchical in order to evolve complexity within reasonable time. A hierarchy of a system is defined as the set of self-contained levels at which the system operates and can be described on. LÄS MER

  3. 2. High Order Symmetric Finite Difference Schemes for the Acoustic Wave Equation

    Författare :Abraham Zemui; Bertil Gustafsson; Leif Abrahamsson; Per Weinerfelt; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; finite element method; mass lumping; high order; finite difference method; wave equation; Numerical Analysis; Numerisk analys;

    Sammanfattning : When someone speaks, or when a piano is played, sound waves are spread through the room. Physically the propagation of sound is governed by the acoustic wave equation. This thesis deals with the problem of finding solutions to this equation by numerical methods. LÄS MER

  4. 3. Development of an efficient solver for detailed kinetics in reactive flows

    Författare :Andrea Matrisciano; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Tabulated chemistry; Detailed chemistry; Stochastic Reactor Model; Progress Variable; Chemical lumping;

    Sammanfattning : The use of chemical kinetic mechanisms in CAE tools for reactive flow simulations is of high importance for studying and predicting pollutant formation. However, usage of complex reaction schemes is accompanied by high computational cost in both 1D and 3-D CFD frameworks. LÄS MER

  5. 4. A Detailed Modeling Study for Primary Reference Fuels and Fuel Mixtures and Their Use in Engineering Applications

    Författare :Syed Ahmed; Förbränningsfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Teknik; Detailed mechanism; Lumping procedure; Reduction technique.; Technological sciences; Fuel blends; n-heptane; Primary Reference Fuels PRF ; Toulene; iso-octane;

    Sammanfattning : The aim of this work is to generate detailed and simplified kinetic models for the oxidation of the Primary Reference Fuels (PRF) n-heptane, iso-octane and their mixtures, with low numbers of species and reactions. These mechanisms are consistent in terms of the choice of kinetic parameters for the different reaction classes. LÄS MER

  7. 5. A hybrid finite element method for electromagnetics with applications in time-domain

    Författare :DAVID DEGERFELDT; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Nitsche s method; antenna arrays; NASA almond; edge elements; scattering; explicit-implicit time-stepping; Maxwell s equations; Finite Element Method; mass lumping; stability analysis; Finite-Differences Time-Domain; periodic structures; shape and material optimization;

    Sammanfattning : In this thesis, a new hybrid method that combines the Finite Element Method (FEM) with the Finite-Difference in Time-Domain (FDTD) method is presented. Tetrahedrons in the unstructured FEM region are connected directly to thehexahedrons in the structured FDTD region. LÄS MER