Search results for "standard deviation"
showing 10 items of 282 documents
Effect of Multizone Refractive Multifocal Contact Lenses on Standard Automated Perimetry
2012
PURPOSE The aim of this study was to evaluate whether the creation of 2 foci (distance and near) provided by multizone refractive multifocal contact lenses (CLs) for presbyopia correction affects the measurements on Humphreys 24-2 Swedish interactive threshold algorithm (SITA) standard automated perimetry (SAP). METHODS In this crossover study, 30 subjects were fitted in random order with either a multifocal CL or a monofocal CL. After 1 month, a Humphrey 24-2 SITA standard strategy was performed. The visual field global indices (the mean deviation [MD] and pattern standard deviation [PSD]), reliability indices, test duration, and number of depressed points deviating at P<5%, P<2%, P<1%, an…
Bollard Segmentation and Position Estimation From Lidar Point Cloud for Autonomous Mooring
2022
This article presents a computer-aided object detection and localization method from lidar 3-D point cloud data. This topic of interest is in the framework of autonomous mooring, where the ship is tied to the rigid structure on-shore (bollard) for autonomous maritime navigation. Using shape and features priors, unlike matching the whole object template to the experimental 3-D point cloud representation of the scene, two customized algorithms: 1) 3-D feature matching (3-DFM) and 2) mixed feature-correspondence matching (MFCM) are presented. The proposed algorithms discriminate and extract the 3-D points corresponding to the noncooperative bollard's surface from the background, thus capable o…
Study of the v3 = 1 State of 80SeF6 by Fourier Transform Spectroscopy
1997
The Fourier transform infrared spectrum of monoisotopic 80SeF6 has been recorded in the 760-792 cm-1 region with an effective resolution of ca. 2.3 x 10(-3) cm-1. The 80SeF6 sample was prepared by burning monoisotopic 80Se powder (99.2%) in an excess of fluorine. The analysis of infrared transitions of the nu3 band enabled the determination of parameters of the Hamiltonian developed up to the third order and the fourth order. The standard deviation obtained is equal to 4 x 10(-4) cm-1 for the third-order development and 3.2 x 10(-4) cm-1 for the fourth-order development. In the two analyses, 2900 lines were assigned and fitted. Copyright 1997 Academic Press. Copyright 1997Academic Press
Effect of local ischemia on induction of cardiac reentries
1992
In this paper, we study the effects of local ischemia on the process of triggering of reentry mechanism. We present computer simulations based on a cellular automata model of the propagation of the depolarizing wave through a ventricular surface element. We simulate a local area of ischemia where effects of refractory period dispersion are investigated. We use a gaussian distribution of the refractory periods characterized by a mean value and a standard deviation. These simulations show that there exist critical conditions necessary to initiate a reentry mechanism invading progressively the whole ventricle.
Direct determination by portable ED-XRF of mineral profile in cocoa powder samples
2019
Abstract The present study has exploited the rapidity of the analysis and the multi-elemental capability of the energy dispersive X- ray fluorescence (ED-XRF) technique for the mineral profile determination in cocoa powder. A fast, cheap and environmental sustainable method without reagent consumption or toxic waste generation has been proposed. The samples can be prepared in the form of pellets of 13 mm in diameter and 2–3 mm thickness. The different internal calibrations used by ED-XRF equipment did not provide accurate results when comparing the mineral profile with the concentration obtained by Inductively Couple Plasma Optical Emission Spectroscopy (ICP-OES) after microwave assisted di…
Uncertainty Propagation in Integrated Urban Water Quality Modelling
2018
Sensitivity and uncertainty assessment of integrated urban drainage water quality models are crucial steps in the evaluation of the reliability of model results. Indeed, the assessment of the reliability of the results of complex water quality models is crucial in understanding their significance. In the case of integrated urban drainage water quality models, due to the fact that integrated approaches are basically a cascade of sub-models (simulating the sewer system, wastewater treatment plant and receiving water body), uncertainty produced in one sub-model propagates to the following ones in a manner dependent on the model structure, the estimation of parameters and the availability and u…
Investigation of temperature coefficients of PV modules through field measured data
2021
Abstract Varying broadband irradiance and temperature are generally known as the major factors influencing the performance of PV modules, but studies have also shown the substantial impact of spectral variations. In this work, a simple and efficient method to calculate the temperature coefficient using long term data is demonstrated. Temperature coefficients of PV modules are estimated from long term performance data following IEC 60891 standard with additional spectral correction, and are compared against the datasheet values. Significant improvement of correlation coefficient from −0.89 to −0.97 is observed during the regression for maximum power temperature coefficient of two poly-crysta…
A method for evaluating rainfall kinetic power by a characteristic drop diameter
2019
Abstract Empirical relationships linking kinetic energy to rainfall intensity are commonly used to estimate rainfall erosivity. In this paper, using the drop-size distribution (DSD) proposed by Marshall and Palmer, a relationship for calculating the rainfall kinetic power was firstly deduced. This equation requires the simultaneous measurement of both the median volume diameter and the rainfall intensity and its application also reveals the drawback of needing the measurement of the whole DSD by an expensive disdrometric technique. Then, using a fictitious precipitation, which is both constituted by droplets having the same diameter (mean volume diameter) and having the same volume of the a…
Aerobic fitness mediates the intervention effects of a school-based physical activity intervention on academic performance. The school in Motion stud…
2021
Highlights • Physical activity is associated with increased aerobic fitness and academic performance. • Little is known on mechanism of physical activity effects on academic performance. • We performed a cluster randomized controlled trial. • Aerobic fitness mediated the intervention effect on academic performance. • Activity increasing aerobic fitness is a strategy to improve academic performance.
Long term analysis of the columnar and surface aerosol relationship at an urban European coastal site
2017
Abstract Simultaneous PM2.5, PM10 and columnar (ground and satellite based) AOD measurements have been analyzed at Burjassot site in the metropolitan area of Valencia (Spain) during the period 2007–2016. The site is representative of a south European city in the Western Mediterranean coastal area, influenced by local urban pollution but also from frequent Saharan dust events. First, multiannual statistics were performed to characterize the main aerosol burden characteristics. The averages and standard deviations resulted 18 ± 9 μg m−3, 25 ± 19 μg m−3, 0.15 ± 0.11, 0.23 ± 0.17, 0.19 ± 0.15 and 1.2 ± 0.3 for PM2.5, PM10, AERONET AOD, MODIS Terra AOD, MODIS Aqua AOD, and AERONET Angstrom expon…