Sökning: "FREQUENCY FUNCTIONS"

Visar resultat 11 - 15 av 353 avhandlingar innehållade orden FREQUENCY FUNCTIONS.

  1. 11. Periodized Thermal Greens Functions and Applications

    Författare :Andro Sabashvili; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; condensed matter physics; Greens function; graphene; DMFT; RPA; GW;

    Sammanfattning : This work describes a new formalism for Fermionic thermal Greens functions that are discretized in imaginary time. The discretization makes the thermal Greens function periodic in imaginary (Matsubara) frequency space and requires a generalisation of the Dyson equation and Luttinger-Ward-Baym-Kadanoff functional. LÄS MER

  3. 12. On time-frequency analysis and pseudo-differential operators for vector-valued functions

    Författare :Patrik Wahlberg; Joachim Toft; Luigi Rodino; Växjö universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; MATHEMATICS; MATEMATIK;

    Sammanfattning : This thesis treats different aspects of time-frequency analysis and pseudodifferential operators, with particular emphasis on techniques involving vector-valued functions and operator-valued symbols. The vector (Banach) space is either motivated by an application as in Paper I, where it is a space of stochastic variables, or is part of a general problem as in Paper II, or arises naturally from problems for scalar-valued operators and function spaces, as in Paper V. LÄS MER

  4. 13. Transient waves in nonstationary media : with applications to lightning and nonlinear media

    Författare :Ingegerd Åberg; Institutionen för elektro- och informationsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; lightning; Klein-Gordon; nonlinear; characteristics; wave splitting; imbedding; sources; propagators; Green functions; direct and inverse scattering; Nonstationary; transient; high-frequency switching; Kerr.; Technological sciences; Teknik;

    Sammanfattning : Propagation of transient waves in nonstationary, inhomogeneous, dispersive, stratified media is considered. Waves originating from sources exterior to the scatterer as well as from internal sources are treated. Algorithms are developed and illustrated by computations of wave phenomena in stationary, nonstationary and weakly nonlinear media. LÄS MER

  5. 14. Estimation and Classification of Non-Stationary Processes : Applications in Time-Frequency Analysis

    Författare :Johan Brynolfsson; Statistical Signal Processing Group; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Time-Frequency Estimation; Parameter Estimation; Reassignment method; Non-Stationary Processes; Smooth spectral estimation; Neural Networks;

    Sammanfattning : This thesis deals with estimation and classification problems of non-stationary processes in a few special cases.In paper A and paper D we make strong assumptions about the observed signal, where a specific model is assumed and the parameters of the model are estimated. LÄS MER

  7. 15. Circuit Design for All-Digital Frequency Synthesizers

    Författare :Muhammad Touqir Pasha; Mark Vesterbacka; Ted Johansson; Jacob Wikner; Darius Jakonis; Linköpings universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : The market for low cost portable electronics is rapidly growing. Physical activity monitors, portable music players, and smart watches are fast becoming a part of daily life. As the market for wearable devices has grown, a primary concern for IC manufacturers is to provide low cost, low power and lightweight circuit solutions. LÄS MER