Sökning: "matrix"

Visar resultat 6 - 10 av 2852 avhandlingar innehållade ordet matrix.

1. 6. Modelling of Drug Release from Reservoir and Matrix Formulations - Multiple Unit Dosage Forms and Swelling and Dissolving Matrix Systems

   Författare :Per Borgquist; Avdelningen för kemiteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; swelling; XEDS; Chemical technology and engineering; Kemiteknik och kemisk teknologi; Polymer technology; biopolymers; Polymerteknik; Pharmaceutical and related technologies; Läkemedelsteknik och relaterad teknik; simulation; single pellet; single-unit release; SEM; reservoir system; poly ethylene oxide ; film-coated; matrix; mathematical model; diffusion; pellet shape; controlled release; polymer dissolution; modelling; ethyl cellulose; Coating; multiple-unit release;

   Sammanfattning : In this work, mathematical models have been developed describing drug release from film-coated reservoir systems as well as drug release and polymer dissolution from swelling and dissolving polymer tablets. The model derivation of both systems is based on a mechanistic approach. The model describing drug release from reservoir systems, i.e. LÄS MER

3. 7. Matrix metalloproteinases in Helicobacter inducedgastritis

   Författare :Philip Bergin; Göteborgs universitet; []
   Nyckelord :Helicobacter pylori; Helicobacter felis; Matrix metalloproteinase; macrophage; ; Gastritis;

   Sammanfattning : Helicobacter pylori infects the stomach and areas of gastric metaplasia in the duodenum. Theinfection leads to peptic ulcers or gastric cancers in 10-20% of infected individuals, while themajority are more or less asymptomatic. However, active chronic gastritis develops in all infectedindividuals, often in association with atrophic gastritis. LÄS MER

4. 8. Modeling the covariance matrix of financial asset returns

   Författare :Gustav Alfelt; Joanna Tyrcha; Taras Bodnar; Vasyl Golosnoy; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Realized covariance; Autoregressive time-series; Goodness-of-fit test; Matrix singularity; Portfolio theory; Wishart distribution; Matrix-variate gamma distribution; Parameter estimation; High-dimensional data; Moore-Penrose inverse; matematisk statistik; Mathematical Statistics;

   Sammanfattning : The covariance matrix of asset returns, which describes the fluctuation of asset prices, plays a crucial role in understanding and predicting financial markets and economic systems. In recent years, the concept of realized covariance measures has become a popular way to accurately estimate return covariance matrices using high-frequency data. LÄS MER

5. 9. Supersymmetric Gauge Theories and Matrix Models

   Författare :Rainer Heise; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; String theory; Effective field theory; Matrix model; Supersymmetric gauge theories;

   Sammanfattning : We discuss recent developments in supersymmetric field theory due to the conjecture of Dijkgraaf and Vafa relating the effective superpotential of such theories to the computation of an associated matrix model. We give a short survey of N=1 supersymmetric gauge theories and state the conjecture. LÄS MER

7. 10. Matrix Algebra for Quantum Chemistry

   Författare :Emanuel H. Rubensson; Pawel Salek; Stefan Goedecker; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; linear scaling; reduced complexity; electronic structure; density functional theory; Hartree-Fock; density matrix purification; congruence transformation; inverse factorization; eigenvalues; eigenvectors; numerical linear algebra; occupied subspace; canonical angles; invariant subspace; Theoretical chemistry; Teoretisk kemi;

   Sammanfattning : This thesis concerns methods of reduced complexity for electronic structure calculations.  When quantum chemistry methods are applied to large systems, it is important to optimally use computer resources and only store data and perform operations that contribute to the overall accuracy. LÄS MER