Search results for "correlation"
showing 10 items of 2282 documents
The resemblance of an autocorrelation function to a power spectrum density for a spike train of an auditory model
2013
In this work we develop an analytical approach for calculation of the all-order interspike interval density (AOISID), show its connection with the autocorrelation function, and try to explain the discovered resemblance of AOISID to the power spectrum of the same spike train.
Focal liver lesions: interobserver and intraobserver agreement of three-dimensional contrast-enhanced ultrasound-assisted volume measurements
2021
Purpose: This study was conducted to assess the interobserver and intraobserver agreement of three-dimensional contrast-enhanced ultrasound (3D-CEUS) volume calculations of focal liver lesions (FLLs).Methods: Thirty-nine patients (15 men and 24 women; mean age, 55.4 years) with 39 Flis (mean size, 3.1 +/- 1.8 cm; size range, 1 to 8 cm) prospectively underwent 3D-CEUS. Four readers calculated the volume of each lesion in an independent and blinded fashion in two separate sessions by means of a semi-automatic, commercially available proprietary software. The differences in lesion volumes (cm(3)) among sessions and readers were assessed using the Mann-Whitney U test and the Kruskal-Wallis test…
Deep semantic lung segmentation for tracking potential pulmonary perfusion biomarkers in chronic obstructive pulmonary disease (COPD): The multi‐ethn…
2019
Background Chronic obstructive pulmonary disease (COPD) is associated with high morbidity and mortality. Identification of imaging biomarkers for phenotyping is necessary for future treatment and therapy monitoring. However, translation of visual analytic pipelines into clinics or their use in large-scale studies is significantly slowed by time-consuming postprocessing steps. Purpose To implement an automated tool chain for regional quantification of pulmonary microvascular blood flow in order to reduce analysis time and user variability. Study type Prospective. Population In all, 90 MRI scans of 63 patients, of which 31 had a COPD with a mean Global Initiative for Chronic Obstructive Lung …
Assessment of Osstell ISQ's reliability for implant stability measurement: a cross-sectional clinical study
2013
Resonance frequency analysis (RFA) allows assess implant stability by measuring implant oscillation frequency on the bone. RFA is an objective and non-invasive method for implant stability measurement, although scarce evidence has been provided so far on its reliability. Objectives: Assess the Osstell ISQ system's reliability (i.e., its measurement reproducibility and repeatability) by means of the intraclass correlation coefficient (ICC) as statistical method. Study Desing: Implants stability registers were completed by means of Osstell ISQ on 85 implants on 23 patients. Six measurements were completed on each implant by means of two different SmartPegs (types I and II); that is, three con…
Intra-Rater Test-Retest Reliability of Self-Reported Child Functioning Module
2020
Determining disability prevalence is an important area for population statistics, especially among young adolescents. The Washington Group on Disability Statistics is one source of reporting disabilities through functional difficulties. However, young adolescents self-reporting this measure is in its infancy. The purpose of this study was to carry out an intra-rater test-retest reliability study on a modified set of items for self-reporting functional difficulties. Young adolescents (n=74; boys=64%; age m=13.7, SD=1.8) completed a self-reported version of the child functioning module in a supervised classroom. The second administration took place two weeks later. Intraclass correlation coef…
A New Fitness Test of Estimating VO2max in Well-Trained Rowing Athletes
2021
BackgroundThis study was designed to investigate the validity of maximal oxygen consumption (VO2max) estimation through the Firstbeat fitness test (FFT) method when using submaximal rowing and running programs for well-trained athletes.MethodsWell-trained flatwater rowers (n = 45, 19.8 ± 3.0 years, 184 ± 8.7 cm, 76 ± 12.9 kg, and 58.7 ± 6.0 mL⋅kg–1⋅min–1) and paddlers (n = 45, 19.0 ± 2.5 years, 180 ± 7.7 cm, 74 ± 9.4 kg, and 59.9 ± 4.8 mL⋅kg–1⋅min–1) completed the FFT and maximal graded exercise test (GXT) programs of rowing and running, respectively. The estimated VO2max was calculated using the FFT system, and the measured VO2max was obtained from the GXT programs. Differences between the…
Intra‐ and inter‐instrument reliability of the Actiwatch 4 accelerometer in a mechanical laboratory setting.
2012
Intra- and Inter-Instrument Reliability of the Actiwatch 4 Accelerometer in a Mechanical Laboratory Setting This study aimed to quantify the intra-and inter-instrument reliability of the Actiwatch 4 accelerometer (AW4) in a mechanical setting. Twenty seven AW4 were attached to an isokinetic dynamometer and subjected to angular acceleration for 30 min at 50 deg/sec representing moderate intensity (MPA condition) and 200 deg/sec representing vigorous intensity (VPA condition), with a repeat trial conducted. Reliability was assessed using coefficient of variation (CV), absolute percent error (APE), and intraclass correlation coefficients (ICC). Mean AW4 activity counts displayed acceptable rel…
Inverse Scattering Solutions with Applications to Electromagnetic Signal Processing
2009
When a signal is recorded that has been physically generated by some scattering process (the interaction of electromagnetic, acoustic or elastic waves with inhomogeneous materials, for example), the ‘standard model’ for the signal (i.e. information content convolved with a characteristic Impulse Response Function) is usually based on a single scattering approximation. An additive noise term is introduced into the model to take into account a range of non-deterministic factors including multiple scattering that, along with electronic noise and other background noise sources, is assumed to be relatively weak. Thus, the standard model is based on a ‘weak field condition’ and the inverse scatte…
Pattern Formation Kinetics for Charged Molecules on Surfaces: Microscopic Correlation Function Analysis
2011
The kinetics of pattern formation and phase separation in a system of two types of oppositely charged molecules with competing short- and long-range interactions on surfaces/interfaces is studied combining three methods: a microscopic formalism of the joint correlation functions, reverse Monte Carlo, and nonequilibrium charge-screening factors. The molecular ordering occurs on the background of the Ostwald ripening and thus is strongly nonequilibrium. We have demonstrated how initial random distribution of molecules is changed for loose similar-molecule aggregates, with further reorganization into dense macroscopic domains of oppositely charged molecules. Pattern formation process is charac…
Searches for small-scale anisotropies from neutrino point sources with three years of IceCube data
2015
Recently, IceCube found evidence for a diffuse signal of astrophysical neutrinos in an energy range of $60\,\mathrm{TeV}$ to the $\mathrm{PeV}$-scale. The origin of those events, being a key to understanding the origin of cosmic rays, is still an unsolved question. So far, analyses have not succeeded to resolve the diffuse signal into point-like sources. Searches including a maximum-likelihood-ratio test, based on the reconstructed directions and energies of the detected down- and up-going neutrino candidates, were also performed on IceCube data leading to the exclusion of bright point sources. In this paper, we present two methods to search for faint neutrino point sources in three years o…