Sökning: "finite order invariants"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden finite order invariants.

1. 1. Arnold-type invariants of curves and wave fronts on surfaces

   Författare :Vladimir Tchernov; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mathematics; Immersion of the circle; generic immersion; curves on surfaces; Legendrian immersion; Legendrian knot; wave fronts on surfaces; Whitney index; Maslov index; regular homotopy; perestroikas of plane curves and fronts; Arnold s basic invariants of plane curves and fronts; finite order invariants; Vassiliev invariants; homotopy groups of the space of curves on a surface; MATEMATIK; MATHEMATICS; MATEMATIK; matematik; Mathematics;

   Sammanfattning : This thesis is devoted to the study of invariants of generic curves and wave fronts on surfaces. The invariants J± and St were axiomatically defined by Arnold as numerical characteristics of generic curves (immersions of the circle)on ℝ2 he introduced J± in the case of generic planar wave fronts. LÄS MER

3. 2. Ekedahl Invariants, Veronese Modules and Linear Recurrence Varieties

   Författare :Ivan Martino; Anders Björner; Volkmar Welker; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ekedahl Invariants; Noether Problem; Bogomolov Multiplier; Cyclic quotient singularities; Veronese Modules; Pile simplicial complex; Semigroup Rings; Betti Numbers; Mathematics; matematik;

   Sammanfattning : The title of this thesis refers to the three parts of which it is composed.The first part concerns the Ekedahl Invariants, new geometric invariants for finite groups introduced in 2009 by Torsten Ekedahl. LÄS MER

4. 3. Modelling of Granular Materials

   Författare :Aylin Ahadi; Mekanik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; hydraulic engineering; Civil engineering; materialteknik; Materiallära; Material technology; binary mixture model; simulations; material modelling; finite element; granular materials; offshore technology; soil mechanics; Väg- och vattenbyggnadsteknik;

   Sammanfattning : The aim of this doctoral study is to develop and implement a material model for granular materials. The course of this work was concentrated upon a non-associated plasticity model with yield surface and the flow potential expressed in terms of the mean stress p and the third stress invariants I3. LÄS MER

5. 4. On the Ising problem and some matrix operations

   Författare :Daniel Andrén; Roland Häggkvist; Henrik Eriksson; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ising problem; phase tansition; matrix multiplicatoin; matrix inversion; Discrete mathematics; Diskret matematik;

   Sammanfattning : The first part of the dissertation concerns the Ising problem proposed to Ernst Ising by his supervisor Wilhelm Lenz in the early 20s. The Ising model, or perhaps more correctly the Lenz-Ising model, tries to capture the behaviour of phase transitions, i.e. how local rules of engagement can produce large scale behaviour. LÄS MER

7. 5. Ghosts and machines : regularized variational methods for interactive simulations of multibodies with dry frictional contacts

   Författare :Claude Lacoursière; Bo Kåggström; Ander Klarbring; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Discrete mechanics; Variational method; Contact problems; Impacts; Least action principle; Saddle point problems; Lagrange Multipliers; Constrained systems; Multibody Systems; Numerical regularization; Constraint realization; Constraint stabilization; Dry friction; Differential Algebraic Equations; Nonsmooth problems; Linear Complementarity; Quaternion algebra; Numerical linear algebra; Physics modeling; Interactive simulation; Numerical stability; Rigid body dynamics; Dissipative systems; Computational physics; Beräkningsfysik;

   Sammanfattning : A time-discrete formulation of the variational principle of mechanics is used to provide a consistent theoretical framework for the construction and analysis of low order integration methods. These are applied to mechanical systems subject to mixed constraints and dry frictional contacts and impacts---machines. LÄS MER