In this paper, we firstly give a brief introduction of expectation maximization (EM) algorithm, and then discuss the initial value sensitivity of expectation maximization algorithm. Subsequently, we give a short proof of EM's convergence. Then, we implement experiments with the expectation maximization algorithm (We implement all the experiments on Gaussion mixture model (GMM) ). Our experiment...

UNLABELLED The high-resolution research tomograph (HRRT) is a dedicated human brain PET scanner. At present, iterative reconstruction methods are preferred for reconstructing HRRT studies. However, these iterative reconstruction algorithms show bias in short-duration frames. New algorithms such as the shifted Poisson ordered-subsets expectation maximization (SP-OSEM) and ordered-subsets weighte...

The stochastic blockmodel (SBM) models the connectivity within and between disjoint subsets of nodes in networks. Prior work demonstrated that rows an SBM’s adjacency spectral embedding (ASE) Laplacian (LSE) both converge law to Gaussian mixtures where components are curved exponential families. Maximum likelihood estimation via Expectation-Maximization (EM) algorithm for a full mixture model (...

Integrating machine learning techniques into RDBMSs is an important task since many real applications require modeling (e.g., business intelligence, strategic analysis) as well querying data in RDBMSs. Without integration, it needs to export the from build a model using specialized ML toolkits and frameworks, import trained back for further querying. Such process not desirable time-consuming re...

BACKGROUND The aim of the study was to explore the influence of various time-of-flight (TOF) and non-TOF reconstruction algorithms on positron emission tomography/computer tomography (PET/CT) image quality. MATERIALS AND METHODS Measurements were performed with a triple line source phantom, consisting of capillaries with internal diameter of ∼ 1 mm and standard Jaszczak phantom. Each of the d...

UNLABELLED A crucial method for investigating patients with coronary artery disease (CAD) is the calculation of the left ventricular ejection fraction (LVEF). It is, consequently, imperative to precisely estimate the value of LVEF--a process that can be done with myocardial perfusion scintigraphy. Therefore, the present study aimed to establish and compare the estimation performance of the quan...

Abstract To evaluate whether quantitative PET parameters of motion-corrected 68 Ga-DOTATATE PET/CT can differentiate between intrapancreatic accessory spleens (IPAS) and pancreatic neuroendocrine tumor (pNET). A total 498 consecutive patients with tumors (NET) who underwent March 2017 July 2019 were retrospectively analyzed. Subjects (n = 43, thereof 7 IPAS) pNET 9) included, resulting in a 45 ...

Abstract Background The goal of this work was to determine the quantitative accuracy and optimal reconstruction parameters for 124 I-PET imaging in presence therapeutic levels 131 I. In effort, images were acquired on a GE D710 PET/CT scanner using NEMA IEC phantom with spheres containing I increasing amounts activity background. At each level, two scans acquired, one centered field view (FOV) ...

In this article, we suggest a new statistical approach considering survival heterogeneity as a breakpoint model in an ordered sequence of time-to-event variables. The survival responses need to be ordered according to a numerical covariate. Our estimation method will aim at detecting heterogeneity that could arise through the ordering covariate. We formally introduce our model as a constrained ...