Search for dissertations about: "PROPAGATION"

Showing result 1 - 5 of 1237 swedish dissertations containing the word PROPAGATION.

2. 1. Cost Propagation - Numerical Propagation for Optimization Problems

   Author : Birgit Grohe; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; optimization; numerical propagation; Cost propagation;

   Abstract : In this thesis, we investigate Cost Propagation,an approach to numerical propagation for optimization problems, where we combine ideas from both Constraint Programming and Combinatorial Optimization. We consider discrete optimization problems with binary variables that can be expressed in the model max_x sum_k g_k(x^k)where the terms g_k(x^k) are distinct arbitrary functions over subsets x^k of x. READ MORE

4. 2. Propagation of some coherent and partially coherent laser beams

   Author : Yangjian Cai; Sailing He; Franco Gori; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; : dark hollow beam; elliptical Gaussian beam; flat-topped beam; twisted anisotropic Gaussian Schell-model; partial coherent; propagation; paraxial optical system; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

   Abstract : In this thesis, we investigate the propagation of some coherent and partially coherent laser beams, including a dark hollow beam (DHB), an elliptical Gaussian beam (EGB), a flat-topped beam and a twisted anisotropic Gaussian Schell-model (TAGSM) beam, through a paraxial optical system or a turbulent atmosphere. Several theoretical models are proposed to describe a DHB of circular or non-circular symmetry. READ MORE

5. 3. 60 GHz Wireless Propagation Channels: Characterization, Modeling and Evaluation

   Author : Carl Gustafson; Institutionen för elektro- och informationsteknik; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; 60 GHz; mm-wave; IEEE 802.11ad; IEEE802.15.3c; Channel measurements; Channel modeling; propagation; MIMO; Beamforming; Spatial Multiplexing;

   Abstract : To be able to connect wirelessly to the internet is nowadays a part of everyday life and the number of wireless devices accessing wireless networks worldwide are increasing rapidly. However, with the increasing number of wireless devices and applications and the amount available bandwidth, spectrum shortage is an issue. READ MORE

6. 4. A Wave Expansion Method for Aeroacoustic Propagation

   Author : Johan Hammar; Gunilla Efraimsson; Ciarán J. O'Reilly; Wim De Roeck; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Sound propagation; Sound generation; Aeroacoustics; Aerodynamics; Computational fluid dynamics; Computational aeroacoustics; Numerical methods; Lighthill; Curle; Ffowcs Williams and Hawkings; Frequency-domain propagation; Wave expansion method.; Vehicle and Maritime Engineering; Farkostteknik;

   Abstract : Although it is possible to directly solve an entire flow-acoustics problem in one computation, this approach remains prohibitively large in terms of the computational resource required for most practical applications. Aeroacoustic problems are therefore usually split into two parts; one consisting of the source computation and one of the source propagation. READ MORE

7. 5. Techniques for Efficient Constraint Propagation

   Author : Mikael Zayenz Lagerkvist; Seif Haridi; Christian Schulte; Pierre Flener; KTH; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; constraint programming; constraint propagation; optimization; Computer science; Datalogi;

   Abstract : This thesis explores three new techniques for increasing the efficiency of constraint propagation: support for incremental propagation, improved representation of constraints, and abstractions to simplify propagation.  Support for incremental propagation is added to a propagator centered propagation system by adding a new intermediate layer of abstraction, advisors, that capture the essential aspects of a variable centered system. READ MORE