Sökning: "positivity"

Visar resultat 1 - 5 av 132 avhandlingar innehållade ordet positivity.

  1. 1. Continuity and Positivity Problems in Pseudo-differential Calculus

    Författare :Joachim Toft; Matematik (naturvetenskapliga fakulteten); []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; funktionsanalys; fourieranalys; Serier; functional analysis; Fourier analysis; Series; Entropy.; Young s inequality; Twisted convolution; Schatten-von Neumann; Lower bounds; Weyl Calculus; Pseudo-differential Operqator; Continuity; Positivity;

    Sammanfattning : The paper deals with various positivity and continuity questions arising in the Weyl calculus of pseudo-differential operators. Let W be a symplectic vector space. LÄS MER

  3. 2. Positive vector bundles in complex and convex geometry

    Författare :Hossein Raufi; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Nakano positivity; vanishing theorems; Prekopa theorem; Griffiths positivity; convex geometry; Ohsawa-Takegoshi extension theorem; dbar-equation; L^2-estimates; singular hermitian metrics; holomorphic vector bundles; holomorphic vector bundles; dbar-equation; L^2-estimates; singular hermitian metrics; Griffiths positivity; Nakano positivity; vanishing theorems; Ohsawa-Takegoshi extension theorem; convex geometry; Prekopa theorem;

    Sammanfattning : This thesis concerns various aspects of the geometry of holomorphic vector bundles and their analytical theory which all, vaguely speaking, are related to the notion of positive curvature in general, and L^2-methods for the dbar-equation in particular. The thesis contains four papers. LÄS MER

  4. 3. Continuity and compositions of operators with kernels in ultra-test function and ultra-distribution spaces

    Författare :Yuanyuan Chen; Joachim Toft; Nenad Teofanov; Linnéuniversitetet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Composition; modulation spaces; positivity; pseudo-differential operators; Schatten-von Neumann operators; twisted convolutions; ultra-distributions; Matematik; Mathematics;

    Sammanfattning : In this thesis we consider continuity and positivity properties of pseudo-differential operators in Gelfand-Shilov and Pilipović spaces, and their distribution spaces. We also investigate composition property of pseudo-differential operators with symbols in quasi-Banach modulation spaces. LÄS MER

  5. 4. Externally positive systems : Analysis and control based on combinatorial polynomials

    Författare :Liam Hamed Taghavian; Mikael Johansson; Cristian R. Rojas; Fabio Pasqualetti; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Linear systems; External positivity; Optimization; Non-overshooting control; Combinatorics; Complete monotonicity; Majorization.; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : Monotonic tracking is required in many control systems, including those that cannot tolerate any overshoots and undershoots in their closed-loop responses. Classical examples are found in vehicle cruise control and liquid tank level control. LÄS MER

  7. 5. Processing affective information after sleep loss

    Författare :Andreas Gerhardsson; Håkan Fischer; Johanna Schwarz; Daniel Lundqvist; Philippe Peigneux; Stockholms universitet; []
    Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; sleep deprivation; sleep restriction; affective bias; emotional working memory; positivity effect; sömnbrist; sömnrestriktion; emotionellt bias; arbetsminne; positivitetseffekten; psykologi; Psychology;

    Sammanfattning : It is not fully understood why we need to sleep, although it is evident that sleep loss has consequences for many emotional and cognitive functions. The last couple of decades, sleep researchers have been increasingly devoted to better understand the relationship between sleep and affect. LÄS MER