Essays about: "4D"

Showing result 1 - 5 of 59 essays containing the word 4D.

  1. 1. Gravitational Collapse of a Massless Scalar Field in a Theory of Minimally Modified Gravity

    University essay from KTH/Fysik

    Author : Atabak Fathe Jalali; [2024]
    Keywords : Theoretical physics; astrophysics; modified gravity; minimally modified gravity; gravitational collapse; VCDM; scalar collapse; apparent horizon; numerical relativity; Teoretisk fysik; astrofysik; modifierad gravitation; minimalt modifierad gravitation; gravitationskollaps; VCDM; skalär kollaps; uppenbar horisont; numerisk relativitet;

    Abstract : This thesis explores the spherically symmetric gravitational collapse of a massless scalar field in a minimally modified gravity theory denoted VCDM (V replaces $\Lambda$ in the $\Lambda$CDM abbreviation), a class of theories propagating the same degrees of freedom as general relativity at the expense of broken 4D diffeomorphism invariance. Numerical evolution of the equations of motion reveals that for small initial scalar profile amplitudes, no black hole forms from the collapse. READ MORE

  3. 2. Effects of Virtual Reality and Trajectory Visualization on Neurosurgical Training

    University essay from KTH/Skolan för elektroteknik och datavetenskap (EECS)

    Author : Max Wippich; [2023]
    Keywords : Virtual reality; Trajectory visualization; Neurosurgical education; External Ventricular Drain Placement; Virtuell verklighet; Banvisualisering; Neurokirurgisk utbildning; Externt ventrikulär dräneringsplacering;

    Abstract : With its increasing potential, Virtual Reality (VR) technology has found a growing presence in medical education. In the domain of neurosurgical training, VR has been thoroughly investigated, but gaps still persist, such as in the field of Minimally Invasive Surgery (MIS) and assistive visualizations. READ MORE

  4. 3. Scene Reconstruction From 4D Radar Data with GAN and Diffusion : A Hybrid Method Combining GAN and Diffusion for Generating Video Frames from 4D Radar Data

    University essay from KTH/Skolan för elektroteknik och datavetenskap (EECS)

    Author : Alexandr Djadkin; [2023]
    Keywords : Deep generative models; Generative adversarial networks; Diffusion models; GAN; DGM; 4D imaging radar; Djupa generativa modeller; Generativa antagonistiska nätverk; Diffusionsmodeller; GAN; DGM; 4D-bildradar;

    Abstract : 4D Imaging Radar is increasingly becoming a critical component in various industries due to beamforming technology and hardware advancements. However, it does not replace visual data in the form of 2D images captured by an RGB camera. READ MORE

  5. 4. Evaluation of the auroral large imagining system for automatic space debris detection

    University essay from Luleå tekniska universitet/Rymdteknik

    Author : Pulmu Pietikäinen; [2023]
    Keywords : Space debris; optical system; auroral imager;

    Abstract : The performance of the auroral large imagining system (ALIS_4D) and an automatic track detection algorithm was evaluated for space debris surveillance and tracking. The evaluation of the ALIS_4D was done through a numerical simulation and data annotations, while the track detection results were manually evaluated. READ MORE

  6. 5. Reconstruction of Accelerated Cardiovascular MRI data

    University essay from Linköpings universitet/Statistik och maskininlärning

    Author : Hussnain Khalid; [2023]
    Keywords : medical imaging; deep learning; CNN; Magnetic resonance imaging; MRI; Cardiac MRI; Cardiac; Cardiovascular; reconstruction; 4D flow MRI; Parallel Imaging; Compressed Sensing; FlowVN; Flow Variational Network; K-space; Reference images; sensitivity maps; Respiratory motion; undersampled images;

    Abstract : Magnetic resonance imaging (MRI), is a noninvasive medical imaging testing techniquewhich is used to produce detailed images of internal structure of the human body, includingbones, muscles, organs, and blood vessels. MRI scanners use large magnets and radiowaves to create images of the body. READ MORE