10 resultados para Lsq


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In this two part study, 811 participants completed the Eysenck Personality Profiler (EPP) and the Honey and Mumford Learning Styles Questionnaire (LSQ) and 263 adults completed the EPP and the Myers-Briggs Type Indicator (MBTI). As predicted there were many significant correlations which add to the concurrent validity of the EPP. When the overlap of the EPP with the MBTI and LSQ is compared with the overlap of the NEO-PI with the MBTI and LSQ (derived from Furnham, 1996a,b) it appears that the EPP has greater similarity with the LSQ, but the NEO-PI has greater similarity with the MBTI. (C) 2001 Elsevier Science Ltd. All rights reserved.

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The aim of this study was to determine how well Gray's model of personality [Gray, J.A. (1982). The neuropsychology of anxiety: an enquiry into the functions of the septo-hippocampal system. Oxfords: Oxford University Press, Gray, J.A. (1987). The psychology of fear and stress. Cambridge: Cambridge University Press], as measured by the Gray Wilson Personality Questionnaire (GWPQ), can provide a full description of personality as measured by the primary scales of the Eysenck Personality Profiler (EPP) and the type scales of the short version or the EPQ-R. Factor analysis of the GWPQ the Anxiety and linpulsivity scales of the EPP and the Learning Styles Questionnaire (LSQ) showed that the GWPQ seemed to measure general activation and inhibition factors, but not the finer features of Gray's theory. When the GWPQ scales were regressed against each scale of the EPP., it was round that they generally provide only a reasonable explanation of the EPP primary scales. It is concluded that the GWPQ measures general propel-ties of Gray's model, that the linpulsivity and Anxiety scales of the EPP also scent related to the GWPQ scales, and that Gray's model of personality provides only a partial explanation of personality in general. (C) 2002 Published by Elsevier Science Ltd. All rights reserved.

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Time series analysis can be categorized into three different approaches: classical, Box-Jenkins, and State space. Classical approach makes a basement for the analysis and Box-Jenkins approach is an improvement of the classical approach and deals with stationary time series. State space approach allows time variant factors and covers up a broader area of time series analysis. This thesis focuses on parameter identifiablity of different parameter estimation methods such as LSQ, Yule-Walker, MLE which are used in the above time series analysis approaches. Also the Kalman filter method and smoothing techniques are integrated with the state space approach and MLE method to estimate parameters allowing them to change over time. Parameter estimation is carried out by repeating estimation and integrating with MCMC and inspect how well different estimation methods can identify the optimal model parameters. Identification is performed in probabilistic and general senses and compare the results in order to study and represent identifiability more informative way.

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This thesis concerns the analysis of epidemic models. We adopt the Bayesian paradigm and develop suitable Markov Chain Monte Carlo (MCMC) algorithms. This is done by considering an Ebola outbreak in the Democratic Republic of Congo, former Zaïre, 1995 as a case of SEIR epidemic models. We model the Ebola epidemic deterministically using ODEs and stochastically through SDEs to take into account a possible bias in each compartment. Since the model has unknown parameters, we use different methods to estimate them such as least squares, maximum likelihood and MCMC. The motivation behind choosing MCMC over other existing methods in this thesis is that it has the ability to tackle complicated nonlinear problems with large number of parameters. First, in a deterministic Ebola model, we compute the likelihood function by sum of square of residuals method and estimate parameters using the LSQ and MCMC methods. We sample parameters and then use them to calculate the basic reproduction number and to study the disease-free equilibrium. From the sampled chain from the posterior, we test the convergence diagnostic and confirm the viability of the model. The results show that the Ebola model fits the observed onset data with high precision, and all the unknown model parameters are well identified. Second, we convert the ODE model into a SDE Ebola model. We compute the likelihood function using extended Kalman filter (EKF) and estimate parameters again. The motivation of using the SDE formulation here is to consider the impact of modelling errors. Moreover, the EKF approach allows us to formulate a filtered likelihood for the parameters of such a stochastic model. We use the MCMC procedure to attain the posterior distributions of the parameters of the SDE Ebola model drift and diffusion parts. In this thesis, we analyse two cases: (1) the model error covariance matrix of the dynamic noise is close to zero , i.e. only small stochasticity added into the model. The results are then similar to the ones got from deterministic Ebola model, even if methods of computing the likelihood function are different (2) the model error covariance matrix is different from zero, i.e. a considerable stochasticity is introduced into the Ebola model. This accounts for the situation where we would know that the model is not exact. As a results, we obtain parameter posteriors with larger variances. Consequently, the model predictions then show larger uncertainties, in accordance with the assumption of an incomplete model.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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GPS active networks are more and more used in geodetic surveying and scientific experiments, as water vapor monitoring in the atmosphere and lithosphere plate movement. Among the methods of GPS positioning, Precise Point Positioning (PPP) has provided very good results. A characteristic of PPP is related to the modeling and/or estimation of the errors involved in this method. The accuracy obtained for the coordinates can reach few millimeters. Seasonal effects can affect such accuracy if they are not consistent treated during the data processing. Coordinates time series analyses have been realized using Fourier or Harmonics spectral analyses, wavelets, least squares estimation among others. An approach is presented in this paper aiming to investigate the seasonal effects included in the stations coordinates time series. Experiments were carried out using data from stations Manaus (NAUS) and Fortaleza (BRFT) which belong to the Brazilian Continuous GPS Network (RBMC). The coordinates of these stations were estimated daily using PPP and were analyzed through wavelets for identification of the periods of the seasonal effects (annual and semi-annual) in each time series. These effects were removed by means of a filtering process applied in the series via the least squares adjustment (LSQ) of a periodic function. The results showed that the combination of these two mathematical tools, wavelets and LSQ, is an interesting and efficient technique for removal of seasonal effects in time series.

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GPS active networks are more and more used in geodetic surveying and scientific experiments, as water vapor monitoring in the atmosphere and lithosphere plate movement. Among the methods of GPS positioning, Precise Point Positioning (PPP) has provided very good results. A characteristic of PPP is related to the modeling and / or estimation of the errors involved in this method. The accuracy obtained for the coordinates can reach few millimeters. Seasonal effects can affect such accuracy if they are not consistent treated during the data processing. Coordinates time series analyses have been realized using Fourier or Harmonics spectral analyses, wavelets, least squares estimation among others. An approach is presented in this paper aiming to investigate the seasonal effects included in the stations coordinates time series. Experiments were carried out using data from stations Manaus (NAUS) and Fortaleza (BRFT) which belong to the Brazilian Continuous GPS Network (RBMC). The coordinates of these stations were estimated daily using PPP and were analyzed through wavelets for identification of the periods of the seasonal effects (annual and semi-annual) in each time series. These effects were removed by means of a filtering process applied in the series via the least squares adjustment (LSQ) of a periodic function. The results showed that the combination of these two mathematical tools, wavelets and LSQ, is an interesting and efficient technique for removal of seasonal effects in time series.

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This study identifies valid orthogonal scales of Gray's animal learning paradigms, upon which his Reinforcement Sensitivity Theory (RST) is based, by determining a revised structure to the Gray-Wilson Personality Questionnaire (GWPQ) (Wilson, Gray, & Barrett, 1990). It is also determined how well Gray's RST scales predict the surface scales of personality, which were measured in terms of Eysenck Personality Profiler (EPP) scales, the EPQ-R and the learning styles questionnaire (LSQ) scales. First, results suggest that independent pathways of RST scales may exist in humans. Second, Fight seems related to Anxiety and not the Fight/Flight system as proposed by RST. Third. a remarkably consistent story emerges in that Extraversion scales are predicted by Fight, Psychoticism scales are predicted by Active-avoidance, Fight and/or Flight, and Neuroticism scales tend not to be predicted at all (except for Anxiety). Fourth, Gray's revised scales are Unrelated to gender and age effects and show a predictable overlap with the LSQ and original GWPQ scales. It is concluded that Gray's model of personality might provide a stable biological basis of many surface scales of personality, but that there must also be other influences on personality. These results question the finer structure of Gray's RST whilst also showing that RST has greater range of applicability than a strict interpretation of theory implies. (C) 2002 Elsevier Science Ltd. All rights reserved.

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De nos jours, la communication écrite joue un rôle primordial pour tout individu qui désire se faire une place dans la société tant sur le plan personnel que socioprofessionnel. Chez les apprenants sourds, le passage à l’écrit du français de la majorité représente un grand défi et leurs phrases contiennent souvent des erreurs de syntaxe. Par exemple, les apprenants sourds auraient tendance à reproduire à l’écrit la syntaxe de la LSQ croyant que les règles de la grammaire de la phrase sont identiques. Dans cet essai, nous nous interrogeons sur les stratégies à adopter pour amener des adultes sourds gestuels à effectuer un transfert efficace de l’oral signé vers le français écrit. Pour ce faire, une situation d’apprentissage (S.A) destinée aux apprenants sourds de niveau présecondaire a été élaborée. Basée sur l’enseignement stratégique et la grammaire de la phrase de base, cette S.A exploite d’abord les bases du fonctionnement de la langue des signes québécoise (LSQ) pour ensuite introduire les notions de la phrase de base et de ses constituants selon la grammaire rénovée. Cette S.A a ensuite été soumise pour validation et rétroaction à la conseillère pédagogique du Centre d’éducation aux adultes où nous travaillons. Ses commentaires, conjugués aux observations notées lors de la mise à l’essai auprès de trois apprenants, ont permis de prendre conscience des forces de cette S.A et d’apporter des ajustements visant à optimiser l’efficacité des différentes activités d’apprentissage.

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La population dont il est question ici, soit celle des personnes aveugles devenues-sourdes a perdu, tardivement, un sens essentiel à la communication; sans l'ouïe, elle est confinée à un monde de silence et d'isolement auquel elle n'est pas préparée. Elle se trouve dépourvue de moyens de communication, d'où l'urgence de mettre en oeuvre un programme pour rétablir une communication fonctionnelle dans ses activités de la vie quotidienne. La langue des signes québécoise (LSQ) constituant pour ces personnes une langue seconde, son apprentissage se révèle complexe, aussi, notre mobile est clair et délimité : restaurer une communication déficiente à l'aide d'un code de signes fonctionnels tout en favorisant la possibilité ultérieure d'acquérir la LSQ, s'il y a lieu. Pour cette raison, les signes sont choisis à même le répertoire de la LSQ et ils le sont selon des critères d'utilité, d'iconicité et d'ergonomie. Suite à l'étude de ces critères, des constituants andragogiques seront analysés, ce qui permettra l'élaboration d'un code de communication fonctionnelle.