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Visar resultat 1 - 5 av 143 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Correlated materials : models and methods

    Författare :Hugo Strand; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; correlated electrons; Hubbard model; multiband Hubbard model; dynamical mean field theory; exact diagonalization; Landau theory; Mott metal-insulator transition; Gutzwiller method; many-body point group symmetry; ironchalcogenides; Kanamori interaction; Slater-Condon interaction;

    Sammanfattning : This thesis encompass a series of studies on methods and models for electron systems with local interactions, relevant for correlated materials. The first study focus on the canonical model for local correlation, the Hubbard model. LÄS MER

  3. 2. Symmetry Breaking Ordering Constraints

    Författare :Zeynep Kiziltan; Andreas Hamfelt; Toby Walsh; Pedro Meseguer; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Datavetenskap; Constraint satisfaction; constraint programming; modelling; symmetry breaking; global constraints; Datavetenskap; Computer science; Datavetenskap;

    Sammanfattning : Many problems in business, industry, and academia can be modelled as constraint programs consisting of matrices of decision variables. Such “matrix models” often have symmetry. In particular, they often have row and column symmetry as the rows and columns can freely be permuted without affecting the satisfiability of assignments. LÄS MER

  4. 3. Symmetry in Randomness : Additive Functionals and Symmetries of Random Trees and Tree-Like Graphs

    Författare :Christoffer Olsson; Stephan Wagner; Ralph Neininger; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Random trees; Random graphs; Additive functionals; Automorphisms; Mathematics; Matematik;

    Sammanfattning : Properties of symmetries in random trees and tree-like graphs are explored. The primary structures studied are Galton-Watson trees, unlabeled unordered trees as well as labeled subcritical graphs. LÄS MER

  5. 4. Improving fingerprint biometrics by local symmetry and fusion

    Författare :Hartwig Fronthaler; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Alignment; Matching; Minutiae Extraction; Image Restoration; Multi-expert Fusion; Biometrics; Symmetry Features; Structure Tensor; Quality Assessment; Fingerprint Recognition; Image Pyramid; Enhancement; Rotational Symmetry; Cascaded Fusion; Monomodal Fusion; Fingerprint;

    Sammanfattning : Fingerprint recognition and biometrics in general have been significantly gaining attention within the last years, not least due to the biometric passport that has been introduced all over Europe and the American immigration management system US-VISIT. The tasks of fingerprint recognition can be broken down to smaller entities, i.e. LÄS MER

  7. 5. Recognition and Evaluation by Video Synthesis Methods and Symmetry Features

    Författare :Dereje Teferi Lemma; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Biometrics; eye detection; video synthesis; liveness detection; camera calibration; damascening; Generalized Structure Tensor; symmetry codes;

    Sammanfattning : Biometrics is being increasingly utilized for person authentication. It requires little or no efforts from the user as compared to traditional non-biometric systems where the user has to memorize PIN codes and passwords or carry pass cards and keys that can be easily forgotten or lost. LÄS MER