Sökning: "Expectation maximization"

Visar resultat 1 - 5 av 45 uppsatser innehållade orden Expectation maximization.

  1. 1. A study about Active Semi-Supervised Learning for Generative Models

    Master-uppsats, Linköpings universitet/Institutionen för datavetenskap

    Författare :Elisio Fernandes de Almeida Quintino; [2023]
    Nyckelord :Semi-Supervised Learning; Active Learning; Generative Models; Mixture Models; Semi-Övervakad Inlärning; Aktiv Inlärning; Generativa Modeller; Mixturmodeller;

    Sammanfattning : In many relevant scenarios, there is an imbalance between abundant unlabeled data and scarce labeled data to train predictive models. Semi-Supervised Learning and Active Learning are two distinct approaches to deal with this issue. LÄS MER

  3. 2. Effects of reconstruction parameters on the image quality and quantification of PET images from PET/MRI and PET/CT systems

    Master-uppsats,

    Författare :Ali Amena Hussain; [2022-03-09]
    Nyckelord :Medical physics; PET CT; PET MRI; OSEM; BPL; NEMA IQ; positron emission tomography; magnetic resonance imaging; computed tomography; ordered Subset Expectation Maximization; The Bayesian Penalized Likelihood;

    Sammanfattning : Aim: To study how reconstruction parameters affect the positron emission tomography (PET) image quality and quantitative results for the different lesion to background radioactivity ratios in three different PET systems. Introduction: Multimodality imaging that combines magnetic resonance imaging (MRI) or computed tomography (CT) with a PET system can produce medical images containing both functional and anatomical information. LÄS MER

  4. 3. Spatiotemporal PET reconstruction with Learned Registration

    Kandidat-uppsats, KTH/Skolan för elektroteknik och datavetenskap (EECS)

    Författare :Pierre Meyrat; [2022]
    Nyckelord :PET; Tomographic reconstruction; Deep Learning; MLEM; PET; Tomografisk rekonstruktion; Deep Learning; MLEM;

    Sammanfattning : Because of the long acquisition time of Positron Emission Tomography scanners, the reconstructed images are blurred by motion. We hereby propose a novel motion-correction maximum-likelihood expectation-maximization algorithm integrating 3D movements between the different gates estimated by a neural network trained on synthetic data with contrast invariance. LÄS MER

  5. 4. Automatic magnetic resonance brain volume measurements to assess the effect of minimised blood sample extraction on brain development in extremely preterm infants

    Master-uppsats, Lunds universitet/Läkarutbildningen

    Författare :Hickmat Hamie; [2021]
    Nyckelord :Magnetic resonance imaging; Brain development; Prematurity; Medicine and Health Sciences;

    Sammanfattning : Aim: To evaluate a pipeline for automatic MRI brain segmentation and volumetric tissue structure quantification in a cohort of extremely preterm infants. Methods: 13 extremely preterm neonates underwent MRI-scanning at a term equivalent age. Seven of these subjects had suitable MRI sequences and were analyzed in the pipeline. LÄS MER

  7. 5. Grouping Similar Bug Reports from Crash Dumps with Unsupervised Learning

    Master-uppsats, KTH/Skolan för elektroteknik och datavetenskap (EECS)

    Författare :Sara Vestergren; [2021]
    Nyckelord :Unsupervised Learning; Bug Report; Duplicate Detection; Clustering; Software Crash; Oövervakad Inlärning; Felrapport; Dublett-detektering; Klustring; Mjukvarukrasch;

    Sammanfattning : Quality software usually means high reliability, which in turn has two main components; the software should provide correctness, which means it should perform the specified task, and robustness in the sense that it should be able to manage unexpected situations. In other words, reliable systems are systems without bugs. LÄS MER