Essays about: "approximation algorithms"

Showing result 16 - 20 of 81 essays containing the words approximation algorithms.

1. 16. Spectroscopic model characterisation of hot exoplanet atmospheres

   University essay from Lunds universitet/Astronomi - Genomgår omorganisation; Lunds universitet/Fysiska institutionen

   Author : Elin Sandvik; [2022]
   Keywords : Transit method; Transmission spectroscopy; Exoplanets; Hot Jupiter; Modelling; Physics and Astronomy;

   Abstract : Hot Jupiters are gas giants under intense stellar radiation with short orbital periods of only a few days. Due to their large radii, hot temperatures, and large scale heights, hot Jupiters can be observationally characterised in detail through spectroscopy over an entire orbital phase. READ MORE

3. 17. Approximating the element matrices in an unfitted finite element method using neural networks

   University essay from Umeå universitet/Institutionen för fysik

   Author : Amanda Bertgren; [2022]
   Keywords : Finite element method; CutFEM; neural networks; machine learning;

   Abstract : This study investigates the possibility of combining an unfitted finite element method, CutFEM, with neural networks, in an attempt to reduce the computational time on evolving domains. Finite element methods are used to solve partial differential equations by fitting a spatial and temporal discretisation to the momentous domain. READ MORE

4. 18. 2D & 3D phase retrieval for propagation-based X-ray phase-contrast tomography

   University essay from Lunds universitet/Synkrotronljusfysik; Lunds universitet/Fysiska institutionen

   Author : Philip Stjärneblad; [2021]
   Keywords : Propagation-based X-ray phase-contrast tomography; PB-PCT; Propagation-based X-ray phase-contrast Imaging; PB-PCI; 2d phase retrieval; 3d phase retrieval; TIE; sinogram consistency; reconstruction artefacts; Science General;

   Abstract : Propagation-based X-ray phase-contrast tomography is a 3d imaging technique that utilizes two-dimensional projections from different angular views $\theta =[0,\pi]$ to reconstruct the 3D object information. The phase-contrast allows for higher feature contrast than conventional transmission tomography, as the phase interference gives rise to a sharp edge contrast. READ MORE

5. 19. Investigation of a Collapsed Cone Superposition Algorithm for dosimetry in brachytherapy

   University essay from Stockholms universitet/Fysikum

   Author : Freja Alpsten; [2021]
   Keywords : Brachytherapy; Collapsed Cone; Model-Based Dose Calculation Algorithms; Radiotherapy;

   Abstract : Background & Purpose: The current standard dosimetry in brachytherapy treatment planning, the TG-43 formalism, ignore the presence of non-water media and finite patient dimensions. This can cause clinically relevant errors in dose estimates. READ MORE

6. 20. Squaring VEGAS -- Multidimensional Integration Using 2D Correlations

   University essay from Lunds universitet/Teoretisk partikelfysik - Geonomgår omorganisation

   Author : Philip Siemund; [2021]
   Keywords : statistics; numerical integration; Monte Carlo integration; VEGAS; Physics and Astronomy;

   Abstract : Multidimensional integrals are used in many areas of physics; electrodynamics, quantum mechanics and statistical physics, to name a few. Many integrals can not be solved analytically, but can instead be approximated numerically. VEGAS is a Monte Carlo integration algorithm, which specializes it in approximating multidimensional integrals. READ MORE