Search for dissertations about: "line source"

Showing result 1 - 5 of 369 swedish dissertations containing the words line source.

2. 1. On the Directivity of Railway Noise Sources

   Author : Xuetao Zhang; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; railway traction noise; railway rolling noise; line source; railway aerodynamic noise; moving source; equivalent source line; De-Dopplerization; sound emission time; sound immission time; directivity; the Doppler factor;

   Abstract : This dissertation deals with the directivity of railway noise. The directivity of railway noise is of particular importance when we have high-rise buildings close to the track, tunnel openings, partial barriers, or when we calculate the maximum sound pressure level during a pass-by based on the sound power level of the different sub-sources of a train. READ MORE

4. 2. Probing the Precipitationshed : A quantification of the biophysical dimensions of terrestrial moisture recycling

   Author : Patrick W. Keys; Line Gordon; Steve Lyon; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; moisture recycling; precipitation; evaporation; variability; ecosystem services; naturresurshushållning; Natural Resources Management;

   Abstract : Terrestrial moisture recycling is the phenomena whereby water evaporates from the land surface, travels through the atmosphere, and fall as precipitation downwind. The interaction of societies with this branch of the hydrological cycle, though critical to the productive functioning of ecosystems around the planet, remains poorly understood. READ MORE

5. 3. Thermal Interference Between Neighbouring Ground-Source Heat Pumps : Tools to Calcualte it and Solutions to Limit it

   Author : Maria Letizia Fascì; Joachim Claesson; Alberto Lazzarotto; Loius Lamarche; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ground source heat pumps; thermal interference; neighbouring geothermal boreholes; finite line source; mitigation strategies; Energiteknik; Energy Technology;

   Abstract : Ground Source Heat Pumps (GSHPs) have emerged as a promising technology for decarbonization of the heating sector. However, their increasing prevalence in densely populated areas may lead to considerable changes in the ground temperature, which can ultimately lead to reduced performance of the systems. READ MORE

6. 4. Sparse Modeling of Grouped Line Spectra

   Author : Ted Kronvall; Statistical Signal Processing Group; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; line spectra; parameter estimation; convex optimization; group-sparsity; block-sparsity; dictionary learning; ADMM; adaptive penalty; total variation; multi-pitch estimation; chroma; audio processing; TDOA; near-field localization; amplitude modulation;

   Abstract : This licentiate thesis focuses on clustered parametric models for estimation of line spectra, when the spectral content of a signal source is assumed to exhibit some form of grouping. Different from previous parametric approaches, which generally require explicit knowledge of the model orders, this thesis exploits sparse modeling, where the orders are implicitly chosen. READ MORE

7. 5. Modeling and Control of Voltage Source Converters Connected to the Grid

   Author : Michael Lindgren; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; voltage source converter; switching frequency; pulse width modulation; IGBT valve; power electronics; small-signal; L-filter; LCL-filter; transfer function; line filter; active filtering; frequency response; sampling frequency;

   Abstract : This thesis deals with the modeling and control of pulse width modulated (PWM) voltage source converters connected to the grid. When voltage source converters are connected to the grid, the power quality and the dynamic performance are affected by the line filter connected between the converter and the grid, and by nonlinearities caused by the switching converter. READ MORE