Search results for "on-line"
showing 10 items of 206 documents
Type-2 Fuzzy Control of a Bioreactor
2009
Abstract—In this paper the control of a bioprocess using an adaptive type-2 fuzzy logic controller is proposed. The process is concerned with the aerobic alcoholic fermentation for the growth of Saccharomyces Cerevisiae a n d i s characterized by nonlinearity and parameter uncertainty. Three type-2 fuzzy controllers heve been developed and tested by simulation: a simple type-2 fuzzy logic controller with 49 rules; a type-2 fuzzyneuro- predictive controller (T2FNPC); a t y p e -2 selftuning fuzzy controller ( T2STFC). The T2FNPC combines the capability of the type-2 fuzzy logic to handle uncertainties, with the ability of predictive control to predict future plant performance making use of a…
Personality Variables as Predictors of Facebook Usage
2014
This study investigates the role of personality factors as predictors of Facebook usage. Data concerning Facebook usage and personality factors from 654 Facebook users were gathered using a web survey. Using path analysis, the results showed Openness was a predictor of Facebook early adoption, Conscientiousness with sparing use, Extraversion with long sessions and abundant friendships, and Neuroticism with high frequency of sessions. The possible role of Agreeableness in predicting low session frequency and friendships needs further validation.
Mixed predictability and cross-validation to assess non-linear Granger causality in short cardiovascular variability series
2006
A method to evaluate the direction and strength of causal interactions in bivariate cardiovascular and cardiorespiratory series is presented. The method is based on quantifying self and mixed predictability of the two series using nearest-neighbour local linear approximation. It returns two causal coupling indexes measuring the relative improvement in predictability along direct and reverse directions, and a directionality index indicating the preferential direction of interaction. The method was implemented through a cross-validation approach that allowed quantification of directionality without constraining the embedding of the series, and fully exploited the available data to maximise th…
AN EXTENDED KALMAN FILTER BASED TECHNIQUE FOR ON-LINE IDENTIFICATION OF UAS PARAMETERS.
2015
The present article deals with the identification,at the same time, of aircraft stability and control parameters taking into account dynamic damping derivatives. Such derivatives,due to the rate of change of the angle of attack, are usually neglected. So the damping characteristics of aircraft dynamics are attributed only on pitch rate derivatives. To cope with the dynamic effects of these derivatives, authors developed devoted procedures to estimate them. In the present paper, a complete model of aerodynamic coefficients has been tuned-up to identify simultaneously the whole set of derivatives. Besides, in spite of the employed reduced order model and/or decoupled dynamics, a six degrees o…
An Extended Kalman Filter-Based Technique for On-Line Identification of Unmanned Aerial System Parameters
2015
ABSTRACT: The present article deals with the identification, at the same time, of aircraft stability and control parameters taking into account dynamic damping derivatives. Such derivatives, due to the rate of change of the angle of attack, are usually neglected. So the damping characteristics of aircraft dynamics are attributed only on pitch rate derivatives. To cope with the dynamic effects of these derivatives, authors developed devoted procedures to estimate them. In the present paper, a complete model of aerodynamic coefficients has been tuned-up to identify simultaneously the whole set of derivatives. Besides, in spite of the employed reduced order model and/or decoupled dynamics, a s…
Modelling the dynamics of the students’ academic performance in the German region of the North Rhine-Westphalia: an epidemiological approach with unc…
2013
Student academic underachievement is a concern of paramount importance in Europe, where around 15% of the students in the last high school courses do not achieve the minimum knowledge academic requirement. In this paper, we propose a model based on a system of differential equations to study the dynamics of the students academic performance in the German region of North Rhine-Westphalia. This approach is supported by the idea that both, good and bad study habits, are a mixture of personal decisions and influence of classmates. This model allows us to forecast the student academic performance by means of confidence intervals over the next few years.
A numerical study of atmospheric signals in the Earth-ionosphere electromagnetic cavity with the Transmission Line Matrix method
2006
[1] The effect of the Earth-ionosphere electromagnetic cavity on the spectrum of an atmospheric signal generated by a broadband electrical current source is analyzed numerically by means of the Transmission Line Matrix (TLM) method. Two new TLM meshes are developed, one with transmission lines connected in parallel and the other with connections in series. The equations describing propagation through these parallel or series meshes are equivalent to the Maxwell equations for TEr or TMr modes in the spherical Earth-ionosphere cavity, respectively. The numerical algorithm obtains Schumann resonance frequencies very close to the experimental ones, confirming that this methodology is a valid nu…
A study of the B and Be star population in the field of the LMC open cluster NGC 2004 with VLT-FLAMES
2005
Observations of hot stars belonging to the young cluster LMC-NGC2004 and its surrounding region have been obtained with the VLT-GIRAFFE facilities in MEDUSA mode. 25 Be stars were discovered; the proportion of Be stars compared to B-type stars is found to be of the same order in the LMC and in the Galaxy fields. 23 hot stars were discovered as spectroscopic binaries (SB1 and SB2), 5 of these are found to be eclipsing systems from the MACHO database, with periods of a few days. About 75% of the spectra in our sample are polluted by hydrogen (Halpha and Hgamma), [SII] and [NII] nebular lines. These lines are typical of HII regions. They could be associated with patchy nebulosities with a bi-m…
RISQUE ASSOCIE A L'UTILISATION DE LA LOI DE BENFORD POUR DETECTER DES VENTES FRAUDULEUSES DE BIENS INNOVANTS A LA MODE
2010
Benford's law has been promoted as providing the auditors with a turnkey solution for fraud detection. The purpose of this paper is to show it is not always possible to detect fraudulent sales with that law. We use sales in volume of game consoles in Japan (since 1989), in United-States, in France, in Germany and in United-Kingdom (since 2000). After reviewing briefly the literature and our study design, the chi-square test and the bias analysis were used to measure the goodness-of-fit to Benford's law. Despite the absence of actual fraud, these sale series of fashion goods are not significantly in conformity with Benford's law. Thus, for the detection of fraudulent sales in this sector, th…
Pas de titre en anglais
2010
Within the quick nano-fabrication techniques evolution and the increasing needs in low space and energy opto-electronic functions on-chip integration, studies and control of electromagnetic resonances of sub-micrometric objects are crucial issues. One aim of this work was then to improve our knowledge of the light-matter interaction. To this end, optical near-field experiments and complementary numerical development of models have been performed to study electromagnetic resonances due to light-matter interaction in sub-micrometric resonators. As an introduction, the first part of the manuscript presents the main phenomena involved in near-field optical microscopy and the used SNOM operation…