Sökning: "integral matrices"

Visar resultat 1 - 5 av 19 avhandlingar innehållade orden integral matrices.

1. 1. Computing abelian varieties over finite fields

   Författare :Stefano Marseglia; Jonas Bergström; Christophe Ritzenthaler; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; abelian varieties; finite fields; period matrices; ideal classes; orders; number fields; integral matrices; Mathematics; matematik;

   Sammanfattning : In this thesis we address the problem of developing effective algorithms to compute isomorphism classes of polarized abelian varieties over a finite field and of fractional ideals of an order in a finite product of number fields.There are well-known methods to efficiently compute the classes of invertible ideals of an order in a number field, but not much has previously been known about non-invertible ideals. LÄS MER

3. 2. New efficient integral algorithms for quantum chemistry

   Författare :Jaime Axel Rosal Sandberg; Zilvinas Rinkevicius; Hans Jørgen Aagaard Jensen; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Teoretisk kemi och biologi; Theoretical Chemistry and Biology;

   Sammanfattning : The contents of this thesis are centered in the developement of new efficient algorithms for molecular integral evaluation in quantum chemistry, as well as new design and implementation strategies for such algorithms aimed at maximizing their performance and the utilization of modern hardware.This thesis introduces the K4+MIRROR algorithm for 2-electron repulsion integrals, a new ERI integral scheme effective for both segmented and general contraction, which surpasses the performance of all previous ERI analytic algorithms published in the literature. LÄS MER

4. 3. Quadrature rules for boundary integral methods applied to Stokes flow

   Författare :Oana Marin; Anna-Karin Tornberg; Fritz Bark; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Computer science; Datavetenskap;

   Sammanfattning :   Fluid phenomena dominated by viscous effects can, in many cases, be modeled by the Stokes equations. The boundary integral form of the Stokes equations reduces the number of degrees of freedom in a numerical discretization by reformulating the threedimensional problem to two-dimensional integral equations to be discretized over the boundaries of the domain. LÄS MER

5. 4. Data driven modeling in the presence of time series structure: : Improved bounds and effective algorithms

   Författare :Othmane Mazhar; Boualem Djehiche; Munther Dahleh; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Time series; Non-asymptotic estimation; Minimax; Change point detection; Hidden Markov model; State space model; Least square; Penalized Regression; Random covariance matrix; Concentration inequality; Chaining integral; Self-normalized martingale inequality; Cramér-Rao inequality; van Trees inequality; Matematisk statistik; Mathematical Statistics;

   Sammanfattning : This thesis consists of five appended papers devoted to modeling tasks where the desired models are learned from data sets with an underlying time series structure. We develop a statistical methodology for providing efficient estimators and analyzing their non-asymptotic behavior. LÄS MER

7. 5. Elastic Wave Scattering by Closed Cracks and Thin Flaws - Multiple Scattering and Resonances

   Författare :Arne S. Eriksson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; SH-wave; evaluation of materials; direct integral equation; singularity expansion; ultrasonic testing;

   Sammanfattning : In this thesis we study elastic wave scattering by thin flaws and closed cracks, which finds applications in ultrasonic testing and evaluation of materials. First we consider the scattering of an SH-wave by a thin finite elastic layer between two elastic half-spaces. LÄS MER