Sökning: "DSA"

Visar resultat 16 - 20 av 29 avhandlingar innehållade ordet DSA.

1. 16. On Dynamic Spectrum Access in Cognitive Radio Networking

   Författare :Said Rutabayiro Ngoga; Blekinge Tekniska Högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Cognitive Radio; Cognitive Radio Networking; Dynamic Spectrum Access; Wireless Communications;

   Sammanfattning : The exploding increase of wireless communications combined with the existing inefficient usage of the licensed spectrum gives a strong impetus to the development and standardization of cognitive radio networking and communications. In this dissertation, a framework for Dynamic Spectrum Access (DSA) is first presented, which is the enabling technology for increasing the spectral efficiency of wireless communications. LÄS MER

3. 17. Dynamic Security Region Assessment

   Författare :Marina Oluic; Mehrdad Ghandari; Bertil Berggren; Jovica V. Milanovic; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; parametrization; power system transient stability; security boundary; short-term voltage instability; Voltage Impasse Region VIR ; parametrisering; spänningsimpassregion VIR ; spänningsinstabilitet; säkerhetsgräns; transient stabilitet i kraftsystem; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : Among a wide variety of topics that are covered by Dynamic Security Assessment (DSA), maintaining synchronous operation and acceptable voltage profiles stand out. These two stability categories are mostly jeopardized in the seconds after a large contingency occurs. LÄS MER

4. 18. Defects in Austenitic Steels and Hard Metals - A DFT-based Study

   Författare :Ruiwen Xie; Levente Vitos; Ilja Turek; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; defects; austenitic steels; cemented carbides; ab-initio; Teknisk materialvetenskap; Materials Science and Engineering;

   Sammanfattning : Materials are never 100% pure due to the limitation of purification method or manufacturing process. Nor are they perfect, especially under deformation. The present work aims to explore different roles played by the defects in austenitic steels and hard metals. LÄS MER

5. 19. Three-dimensional guidance for Endovascular Aortic Repair

   Författare :Giasemi Koutouzi; Göteborgs universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; anatomy deformation; CBCT; EVAR; image fusion; image guidance; image registration;

   Sammanfattning : Image fusion (IF) of preoperative computed tomography (CT) with intraoperative cone-beam CT (CBCT) is a potentially powerful tool for guidance during endovascular aortic repair (EVAR). It may improve intraoperative anatomic visualization and reduce doses of radiation and contrast medium. LÄS MER

7. 20. Deformation Behaviour of Near Fully Pearlitic Railway Steels During Monotonic and Cyclic Loading

   Författare :Niklas Köppen; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; LCF; low cycle fatigue; Near fully pearlitic steels; work hardening; microstructure; tensile deformation; medium carbon steel;

   Sammanfattning : The main conclusions that could be drawn from the present work are that the deformation behaviour of fully and near fully pearlitic steels is very similar and that a combination of low temperature, prestraining and high deformation rates is critical for the performance. This was shown from microscopy studies, tensile, impact and low cycle fatigue (LCF) testing. LÄS MER