Search results for "ERROR"

Ecosistemas locales de aprendizaje ante la globalización tecnológica. Retos de los modelos educativos digitales pospandemia

2021

La educación frente a la covid-19 ha puesto en práctica una infinidad de respuestas, todas urgentes, tentativas, generadas por ensayo y por error, y todavía pendientes de validación. Para comprender mejor el impacto de estas respuestas, el presente artículo defiende, partiendo de la teoría de los ecosistemas de aprendizaje, la necesidad de investigar cómo han influido las tecnologías de ámbito global en la construcción de experiencias locales de aprendizaje. Además, pone de manifiesto la necesidad de estudiar qué tipo de apoyo tanto teórico como práctico se requiere para reconducir los posibles efectos nocivos de la introducción de la tecnología de emergencia. A tal efecto, se describen las…

Artificial neural network for quantitative determination of total protein in yogurt by infrared spectrometry

2009

Abstract A method has been introduced for quantitative determination of protein content in yogurt samples based on the characteristic absorbance of protein in 1800–1500 cm− 1 spectral region by mid-FTIR spectroscopy and chemometrics. Successive Projection Algorithm (SPA) wavelength selection procedure, coupled with feed forward Back-Propagation Artificial Neural Network (BP-ANN) model was the benefited chemometric technique. Relative Error of Prediction (REP) in BP-ANN and SPA-BP-ANN methods for training set was 7.25 and 3.70 respectively. Considering the complexity of the sample, the ANN model was found to be reliable, while the proposed method is rapid and simple, without any sample prepa…

Source document verification in the Mucopolysaccharidosis Type I Registry

2011

Purpose The Mucopolysaccharidosis Type I (MPS I) Registry is an international observational database that tracks the natural history and the outcomes of patients with MPS I. The Registry was a regulatory requirement following the approval of laronidase enzyme replacement therapy for MPS I in 2003. All data are collected voluntarily after informed consent from the patient or family. Data are checked through queries, monthly reviews, and electronic audits to identify missing, inconsistent, or invalid data. This analysis sought to determine overall data accuracy in the Registry through source document verification (SDV). Methods Two phases of SDV were performed. In each phase, Registry data we…

Unitary Space–Time Constellation Design Based on the Chernoff Bound of the Pairwise Error Probability

2008

Unitary space-time constellation design is considered for noncoherent multiple-antenna communications, where neither the transmitter nor the receiver knows the fading coefficients of the channel. By employing the Clarke's subdifferential theorem of the sum of the kappa largest singular values of a unitary matrix, we present a numerical optimization procedure for finding unitary space-time signal constellations of any dimension. The Chernoff bound of the pairwise error probability is used directly as a design criterion. The constellations are found by performing gradient descent search on a family ldquosurrogaterdquo functions that converge to the maximum pairwise error probability. The comp…

2018

Purpose Since the role of short- and long-term intraocular pressure (IOP) fluctuation as a predictor of glaucoma progression is still controversial, the purpose of this study was to investigate the role of IOP fluctuation in a non-selected patient cohort. Materials and methods Two-hundred and forty eyes of 120 glaucoma patients (51% female) with a mean age of 64.5 years were included. Inclusion criteria were at least a visual field (VF) and a 48-hour diurnal phasing of IOP including nocturnal measurement. Glaucoma progression was defined as - if available - confirmed progression of reproducible VF defects in at least three VF examinations or increase of cup area on optic nerve imaging (Heid…

Segmentation of MR brain images with bias artifact

2009

Brain MR Images corrupted by RF- Inhomogeneity (bias artifact) exhibit brightness variations across the image. As a consequence, a standard Fuzzy C-Means (fern) segmentation algorithm may fail. In this work we show a new general-purpose bias removing algorithm, which can be used as a pre-processing step for a fern segmentation. We also compare our experimental results with the ones achieved by using E2 D - H U M filter, showing an improvement in brain segmentation and bias removal.

Direct Objective Quantification of Corneal Haze after Excimer Laser Photorefractive Keratectomy for High Myopia

1996

Purpose: The purpose of the study is to measure regional distribution differences in corneal haze after excimer laser photorefractive keratectomy for high myopia. Methods: The authors developed computerized gradient edge detectors with which were analyzed digitized anterior slit-lamp photographs of 40 eyes, an average of 21.0 plus or minus 14.5 weeks after photorefractive keratectomy for high myopia (−6 to −22 diopters). A treated area and an adjacent untreated area on the anterior corneal surface, each containing six regions, were quantified, and the difference was correlated with various parameters. Results: Mean differences between scarred and clear areas for haze grade 0.5, 1.0, 2.0, 3.…

A Novel Expert System for Non-Invasive Liver Iron Overload Estimation in Thalassemic Patients

2014

Expert Systems can integrate logic based often on computational intelligence methods and they are used in complex problem solving. In this work an Expert System for classifying liver iron concentration in thalassemic patients is presented. In this work, an ANN is used to validate the output of the L.I.O.MO.T (Liver Iron Overload Monitoring in Thalassemia) method against the output of the state-of-the-art method based on MRI T2 assessment for liver iron concentration. The model has been validated with a dataset of 200 samples. The experimental Mean Squared Error results and Correlation show interesting performances. The proposed algorithm has been developed as a plug in for OsiriX Dicom View…

Improved tau polarisation measurement

1996

Using 22 pb−1 of data collected at LEP in 1992 on the peak of the Z resonance, the ALEPH collaboration has measured the polarisation of the tau leptons decaying into $$ev\bar v, \mu v\bar v$$ ,πν, ρν and a1 ν from their individual decay product distributions. The measurement of the tau polarisation as a function of the production polar angle yields the two parametersN τ andN e, where, in terms of the axial and vector couplingsg Al andg Vl,N l=2g Vl gAl/(g Vl 2 +g 2 ). This analysis follows to a large extent the methods devised for the 1990 and 1991 data but with improvements which bring a better understanding of the systematic uncertainties. Combining the 1992 measurements with our previous…

Tiedonlouhinta kyberterrorismin torjuntakeinona

2017

Terrorismi on teknologian kehittyessä siirtynyt kyberavaruuteen ja muuntau-tunut kyberterrorismiksi. Terrorismin uhka ei enää ole vain fyysinen, sillä ky-beravaruus mahdollistaa tietoverkkojen monipuolisen käytön terroristisiin tarpeisiin. Kyberterrorismin uhka on synnyttänyt tarpeen luoda uudenlaisia torjuntakeinoja. Yksi kyberterrorismin torjuntaan käytetyistä menetelmistä on tiedonlouhinta, jonka avulla pystytään tehokkaasti löytämään ennestään tun-tematonta tietoa suurista datamäärästä. Tässä tutkielmassa tutkitaan kyberter-rorismia ilmiönä sekä tiedonlouhinnan menetelmiä ja sovelluksia kyberterro-rismin torjuntaan. Tutkielma on kirjallisuuskatsaus, joka pohjautuu alan tie-teelliseen tu…