Sökning: "gradient-based optimization"

Visar resultat 16 - 20 av 41 avhandlingar innehållade orden gradient-based optimization.

1. 16. Adjoint-based aerodynamic shape optimization

   Författare :Olivier Amoignon; Martin Berggren; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Numerical Analysis; Numerisk analys;

   Sammanfattning : An adjoint system of the Euler equations of gas dynamics is derived in order to solve aerodynamic shape optimization problems with gradient-based methods. The derivation is based on the fully discrete flow model and involves differentiation and transposition of the system of equations obtained by an unstructured and node-centered finite-volume discretization. LÄS MER

3. 17. Phase Retrieval Methods for Electromagnetic Source Modeling

   Författare :Markus Johansson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; source modeling; optimization; SAR; phase retrieval; dosimetry;

   Sammanfattning : Modeling of the field distributions from electromagnetic sources is of interest for various applications including electromagnetic compatibility investigations, near-field to far-field transformations, antenna diagnostics and electromagnetic dosimetry. In order to determine whether exposure safety guidelines, such as the EU directive 2004/40/EC, are complied with, source modeling methods are important. LÄS MER

4. 18. Complex source modeling for electromagnetic dosimetry

   Författare :Markus Johansson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; optimization; phase-retrieval; source modeling; dosimetry; SAR;

   Sammanfattning : Electromagnetic modeling of complex sources is useful in dosimetry applications as well as for near-field to far-field transformations and antennadiagnostics. In order to determine whether exposure safety guidelines, such as the EU directive 2004/40/EC, are complied with, it is important to be able tomodel the field distribution from electromagnetic sources. LÄS MER

5. 19. A study of tailoring acoustic porous material properties when designing lightweight multilayered vehicle panels

   Författare :Eleonora Lind Nordgren; Peter Göransson; Olivier Dazel; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; porous material; optimization; Biot theory; acoustic wave propagation;

   Sammanfattning : The present work explores the possibilities of adapting poro-elastic lightweight acoustic materials to specific applications. More explicitly, a design approach is presented where finite element based numerical simulations are combined with optimization techniques to improve the dynamic and acoustic properties of lightweight multilayered panels containing poro-elastic acoustic materials. LÄS MER

7. 20. Methods for Reliable Image Registration : Algorithms, Distance Measures, and Representations

   Författare :Johan Öfverstedt; Natasa Sladoje; Mattias Heinrich; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Image registration; alignment; local optimization; global optimization; mutual information; normalized gradient fields; representation learning; Computerized Image Processing; Datoriserad bildbehandling;

   Sammanfattning : Much biomedical and medical research relies on the collection of ever-larger amounts of image data (both 2D images and 3D volumes, as well as time-series) and increasingly from multiple sources. Image registration, the process of finding correspondences between images based on the affinity of features of interest, is often required as a vital step towards the final analysis, which may consist of a comparison of images, measurement of movement, or fusion of complementary information. LÄS MER