Search for dissertations about: "spectral gap"

Showing result 1 - 5 of 32 swedish dissertations containing the words spectral gap.

  1. 1. Inverse Problems in Analytic Interpolation for Robust Control and Spectral Estimation

    Author : Johan Karlsson; Anders Lindquist; Alberto Isidori; KTH; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Nevanlinna-Pick Interpolation; Approximation; Model Reduction; Robust Control; Gap-robustness; Sensitivity Shaping; Entropy functional; Spectral Estimation; Weak*-topology; Monge-Kantorovic Transportation; Optimization; systems theory; Optimeringslära; systemteori;

    Abstract : This thesis is divided into two parts. The first part deals with theNevanlinna-Pick interpolation problem, a problem which occursnaturally in several applications such as robust control, signalprocessing and circuit theory. We consider the problem of shaping andapproximating solutions to the Nevanlinna-Pick problem in a systematicway. READ MORE

  2. 2. RHEED and RD studies of III-V semiconductors

    Author : Bert Junno; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; reflectance anisotropy; reflectance difference; RHEED; reflection high energy electron diffraction; III-V semiconductors; GaP; GaAs; InP; InAs; reflection high energy electron diffraction RHEED ; reflectance difference RD ; phase diagrams; surface reconstructions; Fysicumarkivet A:1996:Junno; Halvledarfysik; CBE GaAs; Semiconductory physics; chemical beam epitaxy; surface phase diagrams; RDS; RD; RAS;

    Abstract : The published papers and introductory part of this thesis concentrate on the in-situ characterization of (001) surfaces of GaAs, InAs, InP and GaP. The experimental tools used in these studies were a chemical beam epitaxy (CBE) machine equipped with a reflection high energy electron (RHEED) system and a reflectance difference (RD) optical set-up. READ MORE

  3. 3. Some Markov Processes in Finance and Kinetics : Markov Processes

    Author : Mattias Sundén; Mattias Sunden; Göteborgs universitet; Göteborgs universitet; Gothenburg University; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; CGMY process; Collision kernel; Direct simulation Monte Carlo; Diffusion approximation; Extreme value theory; Feller process; Generalized hyperbolic process; Generalized $z$-process; Infinitesimal generator; Laplace-Beltrami operator; L evy Processes; Long-tailed distribution; Kac equation; Kac model; Markov process; Semigroup; Semi-heavy tailed distirbution; Spectral gap; Subexponential distibrution; Superexponential distribution; Tauberian theorem; Thermostat.; Diffusion approximation;

    Abstract : This thesis consists of four papers. The first two papers treat extremes for L\'evy processes, while papers three and four treat the Kac model with unbounded collision kernel. READ MORE

  4. 4. Technology and properties of InP-based photonic crystal structures and devices

    Author : Naeem Shahid; Srinivasan Anand; Rob W. vad der Heijden; KTH; []
    Keywords : Integrated optics materials; Photonic crystals; Planar waveguides; Dispersion; Band-gap; Mode-gap; mini-stopband; InP; Nanostructure fabrication; dry etching; mass transport; material reflow; reliability; SRA - ICT; SRA - Informations- och kommunikationsteknik;

    Abstract : Photonic crystals (PhCs) are periodic dielectric structures that exhibit a photonic band gap; a range of wavelengths for which light propagation is forbidden. 2D PhCs exhibit most of the properties as their three dimension counterparts with a compatibility with standard semiconductor processing techniques such as epitaxial growth, electron beam lithography, Plasma deposition/etching and electromechanical lapping/polishing. READ MORE

  5. 5. Propagation of Chaos for Kac-like Particle Systems

    Author : Dawan Mustafa; Göteborgs universitet; Göteborgs universitet; Gothenburg University; []
    Keywords : Master equations; chaotic densities; kinetic equations; propagation of chaos; Kac model; thermostatted master equation; Boltzmann equation; BGK equation; quenched process; uniform distribution; spectral gap; approximation process; kinetic equations;

    Abstract : This thesis concerns various aspects of the Kac model. The Kac model is a Markov jump process for a particle system where the total kinetic energy of the system is conserved. This particle model is connected to a limiting equation, describing the evolution of a one-particle density, when the numbers of particles tends to infinity. READ MORE