Development of a mathematical and computer model to assess water quality impacts of hazardous compounds from minor gasoline spills in the inter-tidal zone of the Miami River, Florida

The objective of this study was to develop a model to predict transport and fate of gasoline components of environmental concern in the Miami River by mathematically simulating the movement of dissolved benzene, toluene, xylene (BTX), and methyl-tertiary-butyl ether (MTBE) occurring from minor gasoline spills in the inter-tidal zone of the river. Computer codes were based on mathematical algorithms that acknowledge the role of advective and dispersive physical phenomena along the river and prevailing phase transformations of BTX and MTBE. Phase transformations included volatilization and settling. ^ The model used a finite-difference scheme of steady-state conditions, with a set of numerical equations that was solved by two numerical methods: Gauss-Seidel and Jacobi iterations. A numerical validation process was conducted by comparing the results from both methods with analytical and numerical reference solutions. Since similar trends were achieved after the numerical validation process, it was concluded that the computer codes algorithmically were correct. The Gauss-Seidel iteration yielded at a faster convergence rate than the Jacobi iteration. Hence, the mathematical code was selected to further develop the computer program and software. The model was then analyzed for its sensitivity. It was found that the model was very sensitive to wind speed but not to sediment settling velocity. ^ A computer software was developed with the model code embedded. The software was provided with two major user-friendly visualized forms, one to interface with the database files and the other to execute and present the graphical and tabulated results. For all predicted concentrations of BTX and MTBE, the maximum concentrations were over an order of magnitude lower than current drinking water standards. It should be pointed out, however, that smaller concentrations than the latter reported standards and values, although not harmful to humans, may be very harmful to organisms of the trophic levels of the Miami River ecosystem and associated waters. This computer model can be used for the rapid assessment and management of the effects of minor gasoline spills on inter-tidal riverine water quality. ^

Surface Ocean CO2 Atlas (SOCAT) V1.4

A well-documented, publicly available, global data set of surface ocean carbon dioxide (CO2) parameters has been called for by international groups for nearly two decades. The Surface Ocean CO2 Atlas (SOCAT) project was initiated by the international marine carbon science community in 2007 with the aim of providing a comprehensive, publicly available, regularly updated, global data set of marine surface CO2, which had been subject to quality control (QC). Many additional CO2 data, not yet made public via the Carbon Dioxide Information Analysis Center (CDIAC), were retrieved from data originators, public websites and other data centres. All data were put in a uniform format following a strict protocol. Quality control was carried out according to clearly defined criteria. Regional specialists performed the quality control, using state-of-the-art web-based tools, specially developed for accomplishing this global team effort. SOCAT version 1.5 was made public in September 2011 and holds 6.3 million quality controlled surface CO2 data points from the global oceans and coastal seas, spanning four decades (1968-2007). Three types of data products are available: individual cruise files, a merged complete data set and gridded products. With the rapid expansion of marine CO2 data collection and the importance of quantifying net global oceanic CO2 uptake and its changes, sustained data synthesis and data access are priorities.

Nonholonomically Constrained Dynamics and Optimization of Rolling Isolation Systems

Rolling Isolation Systems provide a simple and effective means for protecting components from horizontal floor vibrations. In these systems a platform rolls on four steel balls which, in turn, rest within shallow bowls. The trajectories of the balls is uniquely determined by the horizontal and rotational velocity components of the rolling platform, and thus provides nonholonomic constraints. In general, the bowls are not parabolic, so the potential energy function of this system is not quadratic. This thesis presents the application of Gauss's Principle of Least Constraint to the modeling of rolling isolation platforms. The equations of motion are described in terms of a redundant set of constrained coordinates. Coordinate accelerations are uniquely determined at any point in time via Gauss's Principle by solving a linearly constrained quadratic minimization. In the absence of any modeled damping, the equations of motion conserve energy. This mathematical model is then used to find the bowl profile that minimizes response acceleration subject to displacement constraint.

Geodesically reversible Finsler 2-spheres of constant curvature

A Finsler space is said to be geodesically reversible if each oriented geodesic can be reparametrized as a geodesic with the reverse orientation. A reversible Finsler space is geodesically reversible, but the converse need not be true. In this note, building on recent work of LeBrun and Mason, it is shown that a geodesically reversible Finsler metric of constant flag curvature on the 2-sphere is necessarily projectively flat. As a corollary, using a previous result of the author, it is shown that a reversible Finsler metric of constant flag curvature on the 2-sphere is necessarily a Riemannian metric of constant Gauss curvature, thus settling a long- standing problem in Finsler geometry.

(Table 3) Description of petrographic profiles in Mittelholstein, Germany

In der vorliegenden Arbeit wird nach morphologischen und sedimentpetrographischen Methoden die Entwässerung der würmzeitlichen Eisrandlagen Mittelholsteins untersucht. Das Untersuchungsgebiet liegt im Mittelteil des nördlichen Holsteins. Im Norden und Osten schließt es etwa mit den Orten Gr. Vollstedt-Blumenthal-Stolpe-Tensfeld, im Süden mit dem Tal der Tensfelder und Oster- bzw. Bram-Au, während es im Westen durch die Höhen der Riß-Moränen zwischen Kellinghusen und Brammer abgegrenzt wird. Morphologisch zeigt sich eine Dreiteilung: im Norden und Osten die würmzeitliche Jungmoräne, im Westen und Süden die rißzeitliche Altmoräne, zwischen beiden die Sander- und Abflussebenen der Würm-Vereisung.

Processus décisionnel des parents concernant la vaccination de leur nourrisson, selon leur génération d’appartenance

Résumé : Malgré le fait que la vaccination soit reconnue comme l’une des mesures de santé publique les plus efficaces, elle est perçue comme non sécuritaire et non nécessaire par un nombre grandissant de parents. Dans ce contexte, la compréhension du processus décisionnel des parents par rapport à la vaccination de leur enfant serait aidante. Le but de cette étude est d’explorer le processus décisionnel des parents concernant la vaccination de leur nourrisson, selon leur génération d’appartenance, soit la génération X ou Y. Une étude de cas descriptive et comparative a été réalisée avec des entrevues semi-structurées ainsi qu’une analyse des sources d’informations consultées par les participantes. Les mères ont été sélectionnées selon leur intention de vaccination pour leur enfant. Les données ont été codifiées et analysées de façon systématique et rigoureuse au niveau intra-cas et inter-cas, co-analysées et ensuite validées avec les participantes. Quatre mères dans chaque génération ont été interviewées, dont trois participantes par génération à deux reprises. Le processus décisionnel est similaire d’une génération à l’autre. Les composantes du processus sont l’attitude initiale envers la vaccination, le processus cognitif, la recherche d’information, la décision, l’acte et l’évaluation rétrospective de l’expérience vécue. Toutes ces composantes sont influencées par des facteurs intrinsèques et extrinsèques. Certaines trouvailles de cette étude ont peu été documentées dans la littérature telles que la perception positive envers la vaccination, l’inconscience du processus, l’importance du déclencheur et le fait de saisir le moment opportun. Malgré la rigueur de cette étude, la principale limite est la saturation des données qui n’a possiblement pas été atteinte pour tous les aspects du processus décisionnel. Même si la norme sociale est favorable à la vaccination, aucune participante n’avait consciemment réfléchi à l’immunisation de son enfant jusqu’à ce qu’un déclencheur soit introduit. Ceci soulève l’enjeu et l’impact de la transmission de l’information adéquate, au moment opportun, et du soutien donné aux parents qui naviguent dans ce processus.

On precise three-dimensional environment modeling via UAV-based photogrammetric systems

Abstract : Images acquired from unmanned aerial vehicles (UAVs) can provide data with unprecedented spatial and temporal resolution for three-dimensional (3D) modeling. Solutions developed for this purpose are mainly operating based on photogrammetry concepts, namely UAV-Photogrammetry Systems (UAV-PS). Such systems are used in applications where both geospatial and visual information of the environment is required. These applications include, but are not limited to, natural resource management such as precision agriculture, military and police-related services such as traffic-law enforcement, precision engineering such as infrastructure inspection, and health services such as epidemic emergency management. UAV-photogrammetry systems can be differentiated based on their spatial characteristics in terms of accuracy and resolution. That is some applications, such as precision engineering, require high-resolution and high-accuracy information of the environment (e.g. 3D modeling with less than one centimeter accuracy and resolution). In other applications, lower levels of accuracy might be sufficient, (e.g. wildlife management needing few decimeters of resolution). However, even in those applications, the specific characteristics of UAV-PSs should be well considered in the steps of both system development and application in order to yield satisfying results. In this regard, this thesis presents a comprehensive review of the applications of unmanned aerial imagery, where the objective was to determine the challenges that remote-sensing applications of UAV systems currently face. This review also allowed recognizing the specific characteristics and requirements of UAV-PSs, which are mostly ignored or not thoroughly assessed in recent studies. Accordingly, the focus of the first part of this thesis is on exploring the methodological and experimental aspects of implementing a UAV-PS. The developed system was extensively evaluated for precise modeling of an open-pit gravel mine and performing volumetric-change measurements. This application was selected for two main reasons. Firstly, this case study provided a challenging environment for 3D modeling, in terms of scale changes, terrain relief variations as well as structure and texture diversities. Secondly, open-pit-mine monitoring demands high levels of accuracy, which justifies our efforts to improve the developed UAV-PS to its maximum capacities. The hardware of the system consisted of an electric-powered helicopter, a high-resolution digital camera, and an inertial navigation system. The software of the system included the in-house programs specifically designed for camera calibration, platform calibration, system integration, onboard data acquisition, flight planning and ground control point (GCP) detection. The detailed features of the system are discussed in the thesis, and solutions are proposed in order to enhance the system and its photogrammetric outputs. The accuracy of the results was evaluated under various mapping conditions, including direct georeferencing and indirect georeferencing with different numbers, distributions and types of ground control points. Additionally, the effects of imaging configuration and network stability on modeling accuracy were assessed. The second part of this thesis concentrates on improving the techniques of sparse and dense reconstruction. The proposed solutions are alternatives to traditional aerial photogrammetry techniques, properly adapted to specific characteristics of unmanned, low-altitude imagery. Firstly, a method was developed for robust sparse matching and epipolar-geometry estimation. The main achievement of this method was its capacity to handle a very high percentage of outliers (errors among corresponding points) with remarkable computational efficiency (compared to the state-of-the-art techniques). Secondly, a block bundle adjustment (BBA) strategy was proposed based on the integration of intrinsic camera calibration parameters as pseudo-observations to Gauss-Helmert model. The principal advantage of this strategy was controlling the adverse effect of unstable imaging networks and noisy image observations on the accuracy of self-calibration. The sparse implementation of this strategy was also performed, which allowed its application to data sets containing a lot of tie points. Finally, the concepts of intrinsic curves were revisited for dense stereo matching. The proposed technique could achieve a high level of accuracy and efficiency by searching only through a small fraction of the whole disparity search space as well as internally handling occlusions and matching ambiguities. These photogrammetric solutions were extensively tested using synthetic data, close-range images and the images acquired from the gravel-pit mine. Achieving absolute 3D mapping accuracy of 11±7 mm illustrated the success of this system for high-precision modeling of the environment.

Techniques for batch reinforcement learning in robotics

This thesis addresses the Batch Reinforcement Learning methods in Robotics. This sub-class of Reinforcement Learning has shown promising results and has been the focus of recent research. Three contributions are proposed that aim to extend the state-of-art methods allowing for a faster and more stable learning process, such as required for learning in Robotics. The Q-learning update-rule is widely applied, since it allows to learn without the presence of a model of the environment. However, this update-rule is transition-based and does not take advantage of the underlying episodic structure of collected batch of interactions. The Q-Batch update-rule is proposed in this thesis, to process experiencies along the trajectories collected in the interaction phase. This allows a faster propagation of obtained rewards and penalties, resulting in faster and more robust learning. Non-parametric function approximations are explored, such as Gaussian Processes. This type of approximators allows to encode prior knowledge about the latent function, in the form of kernels, providing a higher level of exibility and accuracy. The application of Gaussian Processes in Batch Reinforcement Learning presented a higher performance in learning tasks than other function approximations used in the literature. Lastly, in order to extract more information from the experiences collected by the agent, model-learning techniques are incorporated to learn the system dynamics. In this way, it is possible to augment the set of collected experiences with experiences generated through planning using the learned models. Experiments were carried out mainly in simulation, with some tests carried out in a physical robotic platform. The obtained results show that the proposed approaches are able to outperform the classical Fitted Q Iteration.

La gestion participative : facteur de motivation pour des enseignantes et des enseignants du secondaire ou outil de gestion ?

Dans la présente recherche j'envisage d'évaluer si la gestion participative offrirait une nouvelle façon de mobiliser les enseignantes et les enseignants du secondaire dans un projet éducatif qui leur redonnerait le goût de l'école? Si j'en viens à une conclusion affirmative, j'essayerai de dégager dans quels domaines la gestion participative pourrait s'appliquer. Sans être exhaustive, voici une liste de thèmes qui pourraient retenir mon attention: création de nouveaux programmes locaux d'enseignement, conception de la grille-matières, participation aux prises de décision, coopération et élaboration de projets à caractère pédagogique, organisation d'activités étudiantes, mise en place d'un système de tutorat pour les élèves, définition des différentes formes d'encadrement des élèves, gestion des ressources financières, matérielles, et humaines de l'école; implication des enseignantes et des enseignants dans la mise en place du projet éducatif de l'école, application des nouveaux programmes d'études et participation à la préparation de politiques et de règlements de la Commission scolaire. Voici comment j'entends poursuivre ma recherche: d'abord, je définirai la problématique, ensuite, je dépouillerai la littérature scientifique sur la motivation, et la participation, ainsi que sur les liens qui existent entre ces deux concepts. Par la suite, j'arrêterai mon cadre méthodologique, je sonderai des enseignantes et des enseignants d'une polyvalente sur la relation possible existant entre la gestion participative et leur motivation au travail et, enfin, je terminerai par une conclusion et des recommandations. […]

A simple but efficient voice activity detection algorithm through Hilbert transform and dynamic threshold for speech pathologies

A simple but efficient voice activity detector based on the Hilbert transform and a dynamic threshold is presented to be used on the pre-processing of audio signals -- The algorithm to define the dynamic threshold is a modification of a convex combination found in literature -- This scheme allows the detection of prosodic and silence segments on a speech in presence of non-ideal conditions like a spectral overlapped noise -- The present work shows preliminary results over a database built with some political speech -- The tests were performed adding artificial noise to natural noises over the audio signals, and some algorithms are compared -- Results will be extrapolated to the field of adaptive filtering on monophonic signals and the analysis of speech pathologies on futures works

Parameter Identification in a Tuberculosis Model for Cameroon

A deterministic model of tuberculosis in Cameroon is designed and analyzed with respect to its transmission dynamics. The model includes lack of access to treatment and weak diagnosis capacity as well as both frequency-and density-dependent transmissions. It is shown that the model is mathematically well-posed and epidemiologically reasonable. Solutions are non-negative and bounded whenever the initial values are non-negative. A sensitivity analysis of model parameters is performed and the most sensitive ones are identified by means of a state-of-the-art Gauss-Newton method. In particular, parameters representing the proportion of individuals having access to medical facilities are seen to have a large impact on the dynamics of the disease. The model predicts that a gradual increase of these parameters could significantly reduce the disease burden on the population within the next 15 years.

Mesure des sensibilités au taux intérêt des activités des caisses d'épargne et de crédit : une application

La méthodologie proposée vise à estimer les sensibilités des revenus de trois caisses d'épargne et de crédit par rapport aux modifications de taux d'intérêt. Plusieurs études basées sur le MEDAF permettent d'analyser la relation rendement risque. Notre méthodologie se démarque par l'inclusion d'un facteur taux d'intérêt comme variable explicative et par la segmentation des activités à l'intérieur d'une même caisse d'épargne et de crédit. Notre démarche se détaille comme suit: présentation du cadre conceptuel, laquelle comporte une brève revue de la littérature théorique et empirique et résume l'évolution du sujet; description de la procédure utilisée, de l'échantillon et de l'estimation; l'analyse et l'interprétation des résultats obtenus pour trois caisses. Un cahier des procédures expliquant le programme développé pour l'analyse (sur GAUSS) est présenté en annexe.

Geometría diferencial de superficies

Este texto abarca temas como: superficies diferenciales, diferenciación e integración en superficies, formas fundamentales, Curvatura Gaussiana, teorema Egregio y teorema de Gauss-Bonnet. La colección de textos lecciones de matemáticas, iniciativa del departamento de Ciencias Básicas de la Universidad de Medellín (Medellín, Colombia) y su grupo de investigación SUMMA, incluye en cada número la exposición detallada de un tema matemático en particular, tratado con el rigor que muchas veces no es posible lograr en un curso regular de la disciplina. Las matemáticas incluyen diferentes áreas del saber matemático como: álgebra, trigonometría, cálculo, estadística y probabilidades, álgebra lineal, métodos lineales y numéricos, historia de las matemáticas, geometría, matemáticas puras y aplicadas, ecuaciones diferenciales y empelo de softwares matemáticos. Todas las carátulas de la colección vienen ilustradas, a manera de identificación, con diseños de la geometría fractal cuya fuente u origen se encuentra referenciada en las páginas interiores de los textos.

Elementos de geometría

Este texto Elementos de Geometría comprende: Geometría Euclidiana y Geometría del Compás. La Geometría Euclidiana se basa en el uso de la regla (no graduada) y el compás, para la construcción de las figuras geométricas. La Geometría Euclidiana se divide, a su vez, en geometría plana y geometría del espacio; la geometría plana trata de las figuras geométricas cuyos puntos están todos situados en el mismo plano y la geometría del espacio del estudio de figuras tridimensionales. El texto aborda, además, el teorema de Gauss que trata de la condición necesaria y suficiente para que una circunferencia se pueda dividir en partes iguales, mediante el uso de la regla y el compás, y teoremas notables como: teorema de Menelaus, teorema de Ceva, teorema de Stewart y teorema de a Alembert. En la geometría del espacio se incluyó un estudio de los cinco poliedros regulares: tetraedro, exaedro, octaedro, icosaedro y dodecaedro. El libro contiene ejercicios al finalizar cada capítulo, en el orden:\' teoremas, lugares geométricos, máximos y mínimos, y problemas varios, con el fin de desarrollar en el estudiante su espíritu investigativo y creativo. Este texto, es una iniciativa de los profesores del Departamento de Ciencias Básicas de la Universidad de Medellín (Medellín - Colombia) y su grupo de investigación SUMMA, yes un programa del Proyecto Institucional Permanencia con Calidad, cuyo objetivo fundamental es disminuir los niveles de deserción y pérdida académica de los estudiantes.