Search results for "COMPONENT"

Rosacea assessment by erythema index and principal component analysis segmentation maps

2017

RGB images of rosacea were analyzed using segmentation maps of principal component analysis (PCA) and erythema index (EI). Areas of segmented clusters were compared to Clinician’s Erythema Assessment (CEA) values given by two dermatologists. The results show that visible blood vessels are segmented more precisely on maps of the erythema index and the third principal component (PC3). In many cases, a distribution of clusters on EI and PC3 maps are very similar. Mean values of clusters’ areas on these maps show a decrease of the area of blood vessels and erythema and an increase of lighter skin area after the therapy for the patients with diagnosis CEA = 2 on the first visit and CEA=1 on the …

Analysis of inter-atrium differences in paroxysmal and persistent atrial fibrillation using principal component analysis

2007

The pathophysiological mechanisms of atrial fibrillation (AF) are not entirely clear yet, and there is no full explanation for the development and evolution of the arrhythmia. The goal of this study is to find inter-atrium differences in electrophysiological behavior between persistent and paroxysmal AF. The database analyzed contains intra-cardiac records from 14 patients with paroxysmal AF and 10 with persistent AF. Dominant frequency and sample entropy measurements showed that in the paroxysmal group there was a left-to-right gradient. These differences were enhanced after the extraction of the main components with principal component analysis. These findings may be interpreted as a poss…

Event-related potentials to unattended changes in facial expressions: detection of regularity violations or encoding of emotions?

2013

Visual mismatch negativity (vMMN), a component in event-related potentials (ERPs), can be elicited when rarely presented “deviant” facial expressions violate regularity formed by repeated “standard” faces. vMMN is observed as differential ERPs elicited between the deviant and standard faces. It is not clear, however, whether differential ERPs to rare emotional faces interspersed with repeated neutral ones reflect true vMMN (i.e., detection of regularity violation) or merely encoding of the emotional content in the faces. Furthermore, a face-sensitive N170 response, which reflects structural encoding of facial features, can be modulated by emotional expressions. Owing to its similar latency …

Principal component analysis and cluster analysis for measuring the local organisation of human atrial fibrillation

2001

The distribution of atrial electrogram types has been proposed to characterise human atrial fibrillation. The aim of this study was to provide computer procedures for evaluating the local organisation of intracardiac recordings during AF as an alternative to off-line manual classification. Principal components analysis (PCA) reduced the data set to a few representative activations, and cluster analysis (CA) measured the average dissimilarity between consecutive activations of an intracardiac signal. The data set consisted of 106 bipolar signals recorded on 11 patients during electrophysiological studies for catheter ablation. Performances of PCA and CA in distinguishing between organised (t…

Tensor clustering on outer-product of coefficient and component matrices of independent component analysis for reliable functional magnetic resonance…

2019

Background. Stability of spatial components is frequently used as a post-hoc selection criteria for choosing the dimensionality of an independent component analysis (ICA) of functional magnetic resonance imaging (fMRI) data. Although the stability of the ICA temporal courses differs from that of spatial components, temporal stability has not been considered during dimensionality decisions. New method. The current study aims to (1) develop an algorithm to incorporate temporal course stability into dimensionality selection and (2) test the impact of temporal course on the stability of the ICA decomposition of fMRI data via tensor clustering. Resting state fMRI data were analyzed with two popu…

An Emulator Toolbox to Approximate Radiative Transfer Models with Statistical Learning

2015

Physically-based radiative transfer models (RTMs) help in understanding the processes occurring on the Earth’s surface and their interactions with vegetation and atmosphere. When it comes to studying vegetation properties, RTMs allows us to study light interception by plant canopies and are used in the retrieval of biophysical variables through model inversion. However, advanced RTMs can take a long computational time, which makes them unfeasible in many real applications. To overcome this problem, it has been proposed to substitute RTMs through so-called emulators. Emulators are statistical models that approximate the functioning of RTMs. Emulators are advantageous in real practice because…

Excitation Transfer Engineering in Ce-Doped Oxide Crystalline Scintillators by Codoping with Alkali-Earth Ions

2018

This work has been supported by the European Social Fund Measure No. 09.3.3-LMT-K-712 activity Improvement of Researchers Qualification by Implementing the World-Class R&D Projects, and by grant #14.W03.31.0004 of the Russian Federation Government. Authors are grateful to CERN Crystal Clear Collaboration and COST Action TD1401 "Fast Advanced Scintillator Timing (FAST)" for support of collaboration.

Multiple factor analysis: principal component analysis for multitable and multiblock data sets

2013

Network meta-analysis of randomized trials in multiple myeloma: Efficacy and safety in frontline therapy for patients not eligible for transplant

2022

The treatment scenario for newly-diagnosed transplant-ineligible multiple myeloma patients (NEMM) is quickly evolving. Currently, combinations of proteasome inhibitors (PI) and/or immunomodulatory drugs (IMiD) +/- the monoclonal antibody Daratumumab are used for first-line treatment, even if head-to-head comparisons are lacking. To compare efficacy and safety of these regimens, we performed a network meta-analysis (NMA) of 27 phase 2/3 randomized trials including a total of 12935 patients and 23 different schedules. Four efficacy/outcome and one safety indicators were extracted and integrated to obtain (for each treatment) the surface under the cumulative ranking-curve (SUCRA), a metric use…

Indirect chronology method employing rare earth elements to identify Sagunto Castle mortar construction periods

2017

A novel indirect chronology method has been developed to identify Sagunto Castle construction periods. The method is based on the use of inductively coupled plasma mass spectrometry (ICP-MS) to determine rare earth elements (REE) and other trace elements in mortars. Additionally, a no destructive geochemical analysis based on X-ray fluorescence (XRF) was employed for major elements determination. Collected chemical data were processed through Principal Component Analysis (PCA) to highlight any differences among the mortars belonging to different buildings and construction periods. The results show that PCA analysis permits to discriminate construction periods according to mortar sample REE …