Sökning: "symmetry"

Visar resultat 1 - 5 av 535 avhandlingar innehållade ordet symmetry.

  1. 1. Investigation of [N-X-N]+ and [N-C-N]+ complexes in solution : Exploring Geometry, Stability and Symmetry

    Författare :Alavi Karim; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; three center four electron; halonium; carbenium; carbonium; pentavalent; symmetry; NMR; variable temperature; counterion; isotopic perturbation of equilibrium;

    Sammanfattning : Halogen bonding is a weak interaction. In this thesis the three center four electron halogen bond, [N−X−N]+, has been studied. The lighter halogens form highly unstable halonium ions that are reactive towards nucleophiles and their complexes were therefore investigated at low temperatures. 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. Breaking the symmetry : spin splitting of hole subbands in strained quantum wells

    Författare :Oskar Mauritz; KTH; []
    Nyckelord :;

    Sammanfattning : Properties of the subband structure and related propertiesof quantum wells (QWs) are investigated, within the frameworkof the multi-band envelope function method. The subbands of aQW are replaced by discrete Landau levels when a magnetic fieldis applied perpendicular to the plane of the well. LÄS MER

  5. 4. 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

  7. 5. 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