Thesis (Ph. D.)--University of Wisconsin--Madison, 1985. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 300-309).

Depuis plus d'un siècle, les psychologues étudient les mécanismes sous-jacents de l'apprentissage. Il existe actuellement deux théories principales qui peuvent être distinguées :les théories de la formation d'associations et les théories propositionnelles. Selon les théories propositionnelles, l'apprentissage est le produit d'inférences et de raisonnements sur des représentations propositionnelles. En revanche, selon une approche à double processus, l'apprentissage est guidé par le renforcement progressif de l'association qui pourrait être influencée par le raisonnement et interagir avec celui-ci si les participants disposent de suffisamment de temps. L'objectif principal de cette thèse est de contribuer au débat opposant ces deux théories en se focalisant sur une différence centrale entre les deux cadres théoriques :la conscience. Selon les modèles doubles d'apprentissage, ce processus de mise à jour graduelle ne dépend pas nécessairement de la conscience, tout en n'excluant pas qu'il puisse éventuellement aboutir à de telles représentations conscientes. Cependant, selon les modèles propositionnels, l'apprentissage se produit grâce à la capacité de former une représentation consciente de la relation entre les stimuli.Dans la présente thèse, cinq études seront présentées pour répondre à cette question. Dans la première étude, nous nous sommes intéressés à étudier comment le comportement et la conscience changent au cours de l'apprentissage et à démontrer les dissociations entre l'apprentissage conscient et inconscient. Dans une seconde étude, nous avions l'intention de reproduire et d'étendre un paradigme de conditionnement instrumental subliminal (Pessiglione et al. 2008). Les troisième et quatrième études ont utilisé la tâche Temps de réaction sériels pour explorer deux problèmes différents. Dans la troisième étude, nous avons étudié l'accès des participants à leurs ressources cognitives en manipulant l'intervalle entre la réponse du participant et la présentation du stimulus suivant. Dans la quatrième étude, nous avons étudié la relation entre le taux de clignement des yeux, qui est un marqueur indirect de l'activité dopaminergique, et l'apprentissage des séquences. Enfin, le but de notre cinquième étude était d'examiner si les nourrissons étaient sensibles à la force des probabilités transitionnelles ou s'ils extrayaient certains morceaux du flux d’information présenté. / Doctorat en Sciences psychologiques et de l'éducation / info:eu-repo/semantics/nonPublished

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The thesis presents a survey of formalisms for non-monotonic reasoning, providing a sketch of the "state of the art" in the field. Reiter's logic for default reasoning is discussed in detail. Following this, a procedure which can determine the extensions of general finite default theories is demonstrated. The potential impact of this procedure on some of the other research in the field is explored, and some promising areas for future research are indicated. Grounds for cautious optimism about the tractability of default theories capable of representing a wide variety of common situations are presented. / Science, Faculty of / Computer Science, Department of / Graduate

The objective of this Thesis is to explore Poincaré Gauge theories of gravity and expose some contributions to this field, which are detailed below. Moreover, a novel ultraviolet non-local extension of this theory shall be provided, and it will be shown that it can be ghost- and singularity-free at the linear level. First, we introduce some fundamentals of differential geometry, base of any gravitational theory. We then establish that the affine structure and the metric of the spacetime are not generally related, and that there is no physical reason to impose a certain affine connection to the gravitational theory. We review the importance of gauge symmetries in Physics and construct the quadratic Lagrangian of Poincaré Gauge gravity by requiring that the gravitational theorymust be invariant under local Poincaré transformations. We study the stability of the quadratic Poincaré Gauge Lagrangian, and prove that only the two scalar degrees of freedom (one scalar and one pseudo-scalar) can propagate without introducing pathologies. We provide extensive details on the scalar, pseudo-scalar, and bi-scalar theories. Moreover, we suggest how to extend the quadratic Poincaré Gauge Lagrangian so that more modes can propagate safely. We then proceed to explore some interesting phenomenology of Poincaré Gauge theories. Herein, we calculate how fermionic particles move in spacetimes endowed with a nonsymmetric connection at first order in the WKB approximation. Afterwards, we use this result in a particular black-hole solution of Poincaré Gauge gravity, showing that measurable differences between the trajectories of a fermion and a boson can be observed. Motivated by this fact, we studied the singularity theorems in theories with torsion, to see if this non-geodesical behaviour can lead to the avoidance of singularities. Nevertheless, we prove that this is not possible provided that the conditions for the appearance of black holes of any co-dimension are met. In order to see which kind Black Hole solutions we can expect in Poincaré Gauge theories, we study Birkhoff and no-hair theorems under physically relevant conditions. Finally, we propose an ultraviolet extension of Poincaré Gauge theories by introducing non-local (infinite derivatives) terms into the action, which can ameliorate the singular behaviour at large energies. We find solutions of this theory at the linear level, and prove that such solutions are ghost- and singularity-free. We also find new features that are not present in metric Infinite Derivative Gravity.

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Experimental nonlinear dynamics is an important area of study in the modern engineering field, with engineering applications in structural dynamics, structural control, and structural health monitoring. As a result, the discipline has experienced a great influx of research efforts to develop a versatile and reliable experimental methodology. A technical challenge in many experimental studies is the procurement of a device that exhibits the desired nonlinear behavior. As a result, many researchers have longed for a versatile, but accurate, testing methodology that has complete freedom to simulate a wide range of nonlinearities and stochastic behaviors. The objective of this study is to develop a reconfigurable test setup as a tool to be used in a wide range of nonlinear dynamic studies. The main components include a moving mass whose restoring force can accurately be controlled and reprogrammed (with software) based upon measured displacement and velocity readings at each time step. The device offers control over nonlinear characteristics and the equation of dynamic motion. The advantage of having such an experimental setup is the ability to simulate various types of nonlinearities with the same test setup. As a result, the data collected can be used to help validate nonlinear modeling, system identification, and stochastic analysis studies. A physical test apparatus was developed, and various mechanical, electrical, and programming calibrations were performed for reliable experimental studies. To display potential uses for the reconfigurable approach, examples are presented where the device has been used to create physical data for use in change detection and deterioration studies. In addition, a demonstration is presented of the device’s ability to physically simulate a large-scale orifice viscous damper, commonly used in vibration mitigation in bridges and buildings. For a large-scale viscous damper, physical testing is required to ensure structural design properties. However, due to the large scale of the dampers, expensive dynamic loading tests can be carried out at a very iii limited number of facilities. Using the reconfigurable test setup, the dynamic signature of the large-scale viscous damper can accurately be simulated with pre-collected data. The development of a system capable of emulating the restoring force of a nonlinear device with software is a novel approach and requires further calibration for increased reliability and accuracy. A discussion regarding the challenges faced when developing the methodology is presented and possible solutions are recommended. The methodology introduced by this apparatus is very promising. The device is a valuable experimental tool for researchers and designers, allowing for physical data collection, modeling, analysis, and validation of a wide class of nonlinear phenomena that commonly occur in a wide variety of engineering applications.

<p> Although usually only two kinds of statistics, namely Bose-Einstein and Fermi-Dirac statistics, are considered in Quantum Mechanics and in Quantum Field Theory, other kinds of statistics, called collectively parastatistics, are conceivable. We critically review theoretical studies of parastatistics to date, point out and clarify several confusions.</p> <p> We first study the "proofs" so far proposed for the symmetrization postulate which excludes parastatistics, emphasizing their ad hoc nature. Then, after exploring in detail the structure of the quantum mechanical theory of paraparticles, we clarify some confusions concerning the compatibility of parastatistics with the so-called cluster property, which has been an issue of controversy for several years. We show, following a suggestion of Greenberg, that the quantum mechanical theory of paraparticles can be formulated in terms of density matrix compatibly with the cluster property. We also discuss such topics as selection rules for systems with variable numbers of paraparticles, the connection between statistics and permutation characters, and the classification of paraparticles.</p> <p> For the quantum field theory of paraparticles, we study discrete representations of the para-commutation relations and illustrate in detail Greenberg and Messiah's theorem concerning Green's ansatzes. Also, fundamental topics such as the spin-statistic theorem, the TCP theorem and the observability of parafields are discussed on the basis of Green's ansatzes. Finally, we point out that the so-called particle permutation operators do not always define multi-dimensional representations of the permutation group both in first and second quantization theories. This questions the validity of the correspondence between the two theories which has recently been proposed.</p> / Thesis / Doctor of Philosophy (PhD)

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