Sökning: "curved surface"

Visar resultat 1 - 5 av 61 avhandlingar innehållade orden curved surface.

1. 1. Analysis and Design of Conformal Array Antennas

   Författare :Patrik Persson; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Conformal antennas; conformal arrays; UTD; high frequency method; MoM; hybrid method; mutual coupling; singly curved surface; doubly curved surface; geodesics; dielectric covered circular cylinder; non-paraxial region. paraxial region; waveguide fed; Electrical engineering; Elektroteknik;

   Sammanfattning : Today there is a great need for communication between people and even between things, using systems onboard e.g. aircraft, cars, ships and satellites. As a consequence, these communications needs require antennas mounted on or integrated in the surfaces of different vehicles or platforms, i. LÄS MER

3. 2. Time Domain Boundary Element Methods for Acoustic Scattering

   Författare :Georgios Natsiopoulos; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; time domain; curved surface; room acoustics; boss model; boundary element method; regularization; transient; Hermite interpolation; hypersingular; acoustic scattering; vector potential;

   Sammanfattning : In room acoustics, numerical computation of scattering phenomena is an important subject, since it is needed to accurately predict the influence of reflectors, the audience, balconies, etc, on the perceived acoustic quality of auditoria. The large physical volumes of auditoria and the wide frequency content of music and speech, together with the complicated geometries involved however, makes predictions in room acoustics a challenging task from a computational point of view. LÄS MER

4. 3. Invariancy Methods for Points, Curves and Surfaces in Computational Vision

   Författare :Karl Åström; Matematik LTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; curved surface; space curve; planar curve; laser guided vehicles; AGV; autonomous guided vehicles; recognition; reconstruction; image sequence; multiple view geometry; affine; invariant; projective; Mathematics; Matematik;

   Sammanfattning : Many issues in computational vision can be understood from the interplay between camera geometry and the structure of images and objects. Typically, the image structure is available and the goal is to reconstruct object structure and camera geometry. This is often difficult due to the complex interdependence between these three entities. LÄS MER

5. 4. Gas Metal Arc Melt Pool Modelling : Effect of welding position and electromagnetic force mode

   Författare :Pradip Aryal; Isabelle Choquet; Högskolan Väst; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Gas metal arc welding; Gravitational force; Substrate orientation; Electromagnetic force modelling; Free surface deformation; Computational Fluid Dynamics; OpenFOAM; Gasmetallbågsvetsning; Gravitation; Svetsläge; Elektromagnetisk kraftmodellering; Smältytans rörelser; Computational Fluid Dynamics; OpenFOAM; Production Technology; Produktionsteknik;

   Sammanfattning : Gas metal arc is a high-efficiency and widely used heat source for metal processing applied predominantly in welding and additive manufacturing. In this study, it was applied to welding. LÄS MER

7. 5. Grating Based Lasers for Photonic Integration and Surface Emission

   Författare :Peter Modh; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; integrated optics; surface-emitting lasers; laser resonators; optical planar waveguide couplers; unstable-resonator lasers; semiconductor lasers;

   Sammanfattning : This thesis deals with the fabrication and characterization of grating-based integration-compatible semiconductor lasers. Waveguide gratings provide feedback for the laser resonators, and are used to diffract the laser output out of the waveguide for surface-emission. LÄS MER