Sökning: "integral geometry"

Visar resultat 11 - 15 av 47 avhandlingar innehållade orden integral geometry.

1. 11. Application of fast backprojection techniques for some inverse problems of integral geometry

   Författare :Stefan Nilsson; Frank Natterer; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : In this thesis we study some mathematical inverse problems concerning the determination of a function from circular averages, which appear in certain radar applications, and the determination of a function from its line integrals, which appear in the well known problem of computerized tomographic imaging (CT). The thesis is divided into three parts. LÄS MER

3. 12. Extremal eigenvalues and geometry of quantum graphs

   Författare :Andrea Serio; Pavel Kurasov; Annemarie Luger; Evans Harrell; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; quantum graphs; spectral estimates; trace formula; Euler characteristic; Mathematics; matematik;

   Sammanfattning : This thesis consists of four papers concerning topics in the spectral theory of quantum graphs, which are differential operators on metric graphs.In paper I we present a family of graphs with an arbitrary number of cycles for which a certain eigenvalue upper estimate is sharp. LÄS MER

4. 13. Simulation of individual cells in flow

   Författare :Lailai Zhu; Luca Brandt; Michael Graham; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Hydrodynamic interaction; swimming microorganisms; capsule; Stokes flow; finite element method; boundary integral method; general geometry Ewald method; spectral element method; viscoelastic fluid; cellular deformation; flow cytometry; cell sorting; microrheology; Teknisk mekanik; Engineering Mechanics;

   Sammanfattning : In this thesis, simulations are performed to study the motion ofindividual cells in flow, focusing on the hydrodynamics of actively swimming cells likethe self-propelling microorganisms, and of passively advected objects like the red bloodcells. In particular, we develop numerical tools to address the locomotion ofmicroswimmers in viscoelastic fluids and complex geometries, as well as the motion ofdeformable capsules in micro-fluidic flows. LÄS MER

5. 14. Modelling of ultrasonic scattering from a crack in a pipe

   Författare :Jacob Rubenson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Non-Destructive Testing; Cylindrical Geometry; Pipe; Crack; Wave propagation;

   Sammanfattning : This thesis considers elastic wave scattering in an infinitely long cylindrical pipe with an infinitely long internal axial crack. The method used in this thesis is called a hypersingular integral equation method since it starts with an integral representation and by using the Green's tensor of the pipe it can be manipulated to a hypersingular equation for the crack-opening displacement (COD). LÄS MER

7. 15. On Hypersurface Coamoebas and Integral Representations of A-Hypergeometric Functions

   Författare :Jens Forsgård; Boris Shapiro; Elizabeth Wulcan; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; matematik; Mathematics;

   Sammanfattning : This thesis is concerned with coamoebas and their connection to integral representations A-hypergeometric functions. In the first part, we introduce the lopsidedness criterion for coamoebas, and define the lopsided coamoeba. We show that the lopsided coamoeba comes naturally equipped with an order map. LÄS MER