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Dissertations / Theses on the topic 'Continuous variation'
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1
Pack, William C. (William Chappell) 1966. "Variation reduction in a continuous web process." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/50410.
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Thesis (S.M.)--Massachusetts Institute of Technology, Sloan School of Management; and, Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1998.Includes bibliographical references (p. 71).
by William C. Pack.
S.M.
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Xu, Lei. "Phonological variation and word recognition in continuous speech." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1190048116.
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Kwiatkowski, Marek. "Formal computational framework for the study of molecular evolution." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/4765.
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Over the past 10 years, multiple executable modelling formalisms for molecular biology have been developed in order to address the growing need for a system-level understanding of complex biological phenomena. An important class of these formalisms are biology-inspired process algebras, which offer-among other desirable properties - an almost complete separation of model specification (syntax) from model dynamics (semantics). In this thesis, the similarity between this separation and the genotype-phenotype duality in evolutionary biology is exploited to develop a process-algebraic approach to the study of evolution of biochemical systems. The main technical contribution of this thesis is the continuous π-calculus (cπ), a novel process algebra based on the classical π-calculus of Milner et. al. Its two defining characteristics are: continuous, compositional, computationally inexpensive semantics, and a exible interaction structure of processes (molecules). Both these features are conductive to evolutionary analysis of biochemical systems by, respectively, enabling many variants of a given model to be evaluated, and facilitating in silico evolution of new functional connections. A further major contribution is a collection of variation operators, syntactic model transformation schemes corresponding to common evolutionary events. When applied to a cπ model of a biochemical system, variation operators produce its evolutionary neighbours, yielding insights into the local fitness landscape and neutral neighbourhood. Two well-known biochemical systems are modelled in this dissertation to validate the developed theory. One is the KaiABC circadian clock in the cyanobacterium S. elongatus, the other is a mitogen-activated protein kinase cascade. In each case we study the system itself as well as its predicted evolutionary variants. Simpler examples, particularly that of a generic enzymatic reaction, are used throughout the thesis to illustrate important concepts as they are introduced.
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Krautkramer, Jesse. "Cultural transmission, style and continuous variation among north central Sierra Nevada projectile points." [Chico, Calif. : California State University, Chico], 2009. http://csuchico-dspace.calstate.edu/xmlui/handle/10211.4/178.
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Bradfield, M. F. A. (Michael Ford Alexander). "Continuous production of succinic acid by Actinobacillus succinogenes : steady state metabolic flux variation." Diss., University of Pretoria, 2013. http://hdl.handle.net/2263/40826.
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Continuous fermentations were performed in a novel external-recycle, biofilm reactor using D-glucose and CO2 as carbon substrates. Corn steep liquor (CSL) and yeast extract (YE) served as nitrogen sources.
In anaerobic fermentations using medium containing CSL and YE, succinic acid (SA) yields were found to be an increasing function of glucose consumption. The ratio of SA to the major by-product, acetic acid (YAASA), increased from 2.4 g g-1 at a glucose consumption of 15 g L-1, to 5.7 g g-1 at a glucose consumption of 46 g L-1. For medium containing no CSL, YAASA remained near 1.97 g g-1, exceeding this for cases where biofilm grown on CSL-containing medium was present.
The ratio of formic acid to acetic acid (YAAFA), for CSL-containing medium, decreased from an equimolar value (0.77 g g-1) at a glucose consumption of 10 g L-1 to zero at 46 g L-1 glucose consumed. In contrast, YAAFA for YE-only medium remained at 0.77 g g-1. Therefore, pyruvate was metabolised solely by pyruvate-formate lyase when no CSL was present.
The highest SA yield obtained on glucose, SA titre and SA productivity were 0.91 g g-1, 48.5 g L-1 and 9.4 g L-1 h-1, respectively, all for medium containing CSL. Medium that included CSL significantly outperformed medium that excluded CSL, achieving 64%, 21% and 203% greater SA titres, yields on glucose and productivities respectively.
Metabolic flux analyses based on the established C3 and C4 metabolic pathways of Actinobacillus succinogenes revealed that the increase in YAASA, for CSL-containing fermentations, could not be attributed to the decrease in formate and biomass formation, and that an additional source of reducing power was present. The fraction of reducing power (NADH) unaccounted for increased with glucose consumption, suggesting that the maintenance or non-growth metabolism encountered at higher SA titres differs from the growth metabolism. It is postulated that the additional reducing power originates from an active pentose phosphate pathway in non-growing cells or from an undetected component(s) in the fermentation medium. No major metabolic flux variations were found in fermentations that excluded CSL.Dissertation (MEng)--University of Pretoria, 2013.
gm2014
Chemical Engineering
unrestricted
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XU, TIJIE. "Detection of Final Solidification Due to Variation of Ferrostatic Pressure during Continuous Casting." Thesis, KTH, Materialvetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-215960.
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This paper presents an investigation on using the variation of ferrostatic pressure exerted by the molten steel in the strand to the support rolls during continuous casting to detect the location of the final solidification. The final solidification point is of high importance for applying soft reduction during continuous casting in order to ensure inner quality and achieve high productivity. The measurement was conducted at one of the casters at SSAB Oxelösund, of which all the support rolls are separately mounted. The project finds that this method shows promising results and can help to narrow down the range of the location due to certain interferences and noises. The ferrostatic pressure decrease during tail-out and the variation of whether a pressure drop exists is the dividing line of full and partial solidification. With the promising results achieved, more effort should be put to further improve the method.
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Marak, Laszlo. "On continuous maximum flow image segmentation algorithm." Phd thesis, Université Paris-Est, 2012. http://tel.archives-ouvertes.fr/tel-00786914.
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In recent years, with the advance of computing equipment and image acquisition techniques, the sizes, dimensions and content of acquired images have increased considerably. Unfortunately as time passes there is a steadily increasing gap between the classical and parallel programming paradigms and their actual performance on modern computer hardware. In this thesis we consider in depth one particular algorithm, the continuous maximum flow computation. We review in detail why this algorithm is useful and interesting, and we propose efficient and portable implementations on various architectures. We also examine how it performs in the terms of segmentation quality on some recent problems of materials science and nano-scale biology
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Tadepally, Harika. "Spatiotemporal Variation of Continuous PM2.5 In Cincinnati: Analyzing The Impacts of Local-Scale Emissions Versus Meteorological Variability." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1504802386325803.
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Holly, Sean Michael. "Lean manufacturing in a semiconductor environment : use of variation analysis to focus continuous improvement efforts." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/37132.
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Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M. in Ocean Engineering)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; in conjunction with the Leaders for Manufacturing Program at MIT, 2006.Includes bibliographical references (leaf 58).
Intel's FAB 17 (F17), in an effort to remain competitive and reduce production cycle time, recently committed to adopt lean manufacturing as their approach to continuous improvement. To aid in this effort, the factory staff has dedicated a group people to develop tools based on lean manufacturing principles. Over the last 18 months, they have created three systematic approaches to address various forms of throughput variation, Autonomous Manufacturing (AM), Planned Maintenance (PM), and Waste Elimination (WE). Autonomous Manufacturing focuses on refurbishing manufacturing tools to new or better condition, up-skilling manufacturing technicians, and differentiating abnormal from normal operating conditions. It is meant to address throughput variation as a direct result of old, poorly maintained tools. Planned Maintenance focuses on keeping refurbished tools in new or better conditions, level loading maintenance activities, and minimizing manufacturing tool downtime due to scheduled maintenance activities. It is meant to address throughput variation as a direct result of tool availability variation. Finally, Waste Elimination focuses on optimizing the flow of information, people, and material.
(cont.) It is meant to address throughput variation as a direct result of inefficient flow through the manufacturing process. This thesis provides an overview of F17's lean journey. It shows that F17 has done an excellent job of developing an infrastructure to support their lean transformation. Going forward, their major challenge will be ingraining the new principles into the existing organizational structure. A variation analysis approach uses a simple model of daily production of an operation, several key metrics that relate work in progress (WIP) flow to tool performance, and a graphical display of WIP flow and tool performance. A case study conducted identifies the most probable source of throughput variation as arrivals at one operation, tool performance at another operation, and WIP management at a third operation.
by Sean Michael Holly.
S.M.in Ocean Engineering
M.B.A.
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Siyasiya, Charles Witness. "The transformation behaviour and hot strength of 3CR12 during the continuous casting process." Diss., Pretoria : [s.n.], 2004. http://upetd.up.ac.za/thesis/available/etd-06202005-134528.
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Garcia, Diez Raul [Verfasser], Stefan [Gutachter] Eisebitt, Mathias [Gutachter] Richter, and Simone [Gutachter] Raoux. "Characterization of nanoparticles by continuous contrast variation in small-angle X-ray scattering / Raul Garcia Diez ; Gutachter: Stefan Eisebitt, Mathias Richter, Simone Raoux." Berlin : Technische Universität Berlin, 2017. http://d-nb.info/1156012457/34.
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Plunkett, Brandi Lyn. "Estimating third -party examiners' scoring stability on selected applications to the Texas Award for Performance Excellence." Texas A&M University, 2006. http://hdl.handle.net/1969.1/4785.
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This study was an attempt to add to existing research by estimating the ability of
third-party examiners to assess whether or not an organization successfully implemented
strategies based on the criteria of the Texas Award for Performance
Excellence (TAPE). The TAPE is given each year by the Quality Texas Foundation
and recognizes organizations that demonstrate superior performance as it is defined
by customer satisfaction and continuous improvement. The TAPE is a state-level
award for quality that uses the same criteria as the Malcolm Baldrige National
Quality Award for Performance Excellence.
This research was an analysis of the TAPE process at the level of examiners, also
known as the Board of Examiners. The Board is made up of approximately 150
experienced professionals from several types of business sectors and is responsible
for evaluating organizational self-assessments.
In this quantitative study, data were converted from the Quality Texas Foundation
into a database. Because the set of the TAPE applicants included in the study consisted of the entire population of TAPE applicants selected from 2001 to 2004,
descriptive statistics were appropriate for producing informative data that could be
analyzed for variation and stability in the scoring process. Exploration of patterns in
descriptive statistics and multivariate analysis of variance were the primary tools used
in this particular study along with CronbachâÂÂs Alpha as an indicator of reliability.
Since scoring for the TAPE is based on an individual examinerâÂÂs best subjective
assessment, it was impossible to have one objective score against which all the other
scores could be measured. The team consensus score was therefore used as the true
score for measurement.
Establishing reliability of examinersâ scores was a problem due to the fact that
organizations and teams did not repeat. Results from the study led to the conclusion
that there was insufficient evidence to make a determination on what influences
examinersâ scoring consistency. More data will need to be collected in such a way so
as to make it possible to identify that impact consistency of examiner scores.
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Stöber, Jakob [Verfasser], Claudia [Akademischer Betreuer] Czado, Roger M. [Akademischer Betreuer] Cooke, and Andrew J. [Akademischer Betreuer] Patton. "Regular Vine Copulas with the simplifying assumption, time-variation, and mixed discrete and continuous margins / Jakob Stöber. Gutachter: Roger M. Cooke ; Andrew J. Patton ; Claudia Czado. Betreuer: Claudia Czado." München : Universitätsbibliothek der TU München, 2013. http://d-nb.info/1037198476/34.
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Clonts, Charlène. "Ontophonie et pictopoésie dans l'oeuvre de Gherasim Luca. : etude de la "variation continue"." Thesis, Pau, 2016. http://www.theses.fr/2016PAUU1006/document.
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Cette thèse étudie le processus de variation continue comme une trame de fond de l’oeuvre complète de Gherasim Luca, afin de mettre en valeur ses aspects plastiques et phoniques, leur articulation ainsi que la façon dont la pictopoésie et l’ontophonie participent à l’autogénération textuelle. Considérant l’oeuvre à la croisée des arts, l’analyse souligne la structure des espaces textuel et iconique. Elle s’intéresse en outre aux figures (personae) émergeant d’une esthétique protéiforme et à l’espace figural du langage, mettant aussi à l’épreuve la théorie deleuzienne de la variation continue pour en montrer les ressorts et les dépassements. Enfin, la mise en oeuvre organique, phonique et linguistique del’ontophonie interroge les voix/voies nouvelles établies par la poésie orale et la médiopoétique, ménageant un accès vers l’analyse de la répétition et de la reformulation en tant que genèse infinieThe aim of this PHD is to study the process of the continuous variation, as the guiding principle for the complete works of Gherasim Luca. The purpose is to highlight both its plastic and its phonic aspects, how they work together, and also the way pictopoésie and ontophonie help create a perpetual selfgenerated text. Since the works stand at the crossroads of several arts, this analysis underlines the structure of the iconic and textual spaces. One of the axis of research, that focuses on the persona, as it emerges from a protean aesthetics, and on the figurative space proper to language, calls thus intoquestion Deleuze’s theory of “continuous variation”, while showing its internal mechanism and its exceedance. Finally, the phonic, the linguistic and the physical performance, in staging the ontophonie, brings into question the voices and the media as a means, established by the oral poetry and the mediopoetics, granting access to an analysis based on endless repetition and reformulation
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Fonseca, De Sam Bento Ribeiro Manuel. "Suprasegmental representations for the modeling of fundamental frequency in statistical parametric speech synthesis." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31338.
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Statistical parametric speech synthesis (SPSS) has seen improvements over recent years, especially in terms of intelligibility. Synthetic speech is often clear and understandable, but it can also be bland and monotonous. Proper generation of natural speech prosody is still a largely unsolved problem. This is relevant especially in the context of expressive audiobook speech synthesis, where speech is expected to be fluid and captivating. In general, prosody can be seen as a layer that is superimposed on the segmental (phone) sequence. Listeners can perceive the same melody or rhythm in different utterances, and the same segmental sequence can be uttered with a different prosodic layer to convey a different message. For this reason, prosody is commonly accepted to be inherently suprasegmental. It is governed by longer units within the utterance (e.g. syllables, words, phrases) and beyond the utterance (e.g. discourse). However, common techniques for the modeling of speech prosody - and speech in general - operate mainly on very short intervals, either at the state or frame level, in both hidden Markov model (HMM) and deep neural network (DNN) based speech synthesis. This thesis presents contributions supporting the claim that stronger representations of suprasegmental variation are essential for the natural generation of fundamental frequency for statistical parametric speech synthesis. We conceptualize the problem by dividing it into three sub-problems: (1) representations of acoustic signals, (2) representations of linguistic contexts, and (3) the mapping of one representation to another. The contributions of this thesis provide novel methods and insights relating to these three sub-problems. In terms of sub-problem 1, we propose a multi-level representation of f0 using the continuous wavelet transform and the discrete cosine transform, as well as a wavelet-based decomposition strategy that is linguistically and perceptually motivated. In terms of sub-problem 2, we investigate additional linguistic features such as text-derived word embeddings and syllable bag-of-phones and we propose a novel method for learning word vector representations based on acoustic counts. Finally, considering sub-problem 3, insights are given regarding hierarchical models such as parallel and cascaded deep neural networks.
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Sanhaji, Mani Ahmed. "Contribution à la réalisation d'un système de transmission de couple à vitesse variable." Rouen, 1995. http://www.theses.fr/1995ROUES057.
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Les travaux de la thèse portent sur une contribution à la réalisation d'un système de transmission de couple à vitesse variable afin d'aboutir à ce que l'on pourrait appeler une boite de vitesse électromécanique à variation continue. Un moteur asynchrone et un alternateur sont couplés de façon rigide par leurs rotors. Le stator du moteur asynchrone est entraîné en rotation par l'application d'une puissance motrice extérieure P1 avec un couple de rotation G1. Le stator de l'alternateur, qui est le siège des courants induits, tourne selon la puissance P2 transmise avec un couple G2. L'énergie électrique fournie par les phases statoriques de l'alternateur est récupérée afin de contribuer à l'alimentation électrique du système. Le projet a pour but de régler le rapport G2/G1 avec un rendement P2/P1 maximum. Dans un premier temps, nous proposons les solutions technologiques pour guider en rotation les stators du moteur asynchrone et de l'alternateur. Nous traitons ensuite le problème des pertes d'énergie au cours du régime transitoire du système de transmission de couple. Grâce à la méthodologie de commande proposée pour les machines, nous montrons qu'un réglage judicieux de la durée du régime transitoire permet de réduire ces pertes d'énergie. Cette méthodologie consiste d'une part à maintenir constant le flux statorique du moteur asynchrone, et d'autre part à varier sa fréquence statorique suivant une rampe linéaire.
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Wang, Ying. "Branching Processes: Optimization, Variational Characterization, and Continuous Approximation." Doctoral thesis, Universitätsbibliothek Leipzig, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-62048.
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In this thesis, we use multitype Galton-Watson branching processes in random environments as individual-based models for the evolution of structured populations with both demographic stochasticity and environmental stochasticity, and investigate the phenotype allocation
problem. We explore a variational characterization for the stochastic evolution of a structured population modeled by a multitype Galton-Watson branching process. When the population under consideration is large and the time scale is fast, we deduce the continuous approximation for multitype Markov branching processes in random environments.
Many problems in evolutionary biology involve the allocation of some limited resource among several investments. It is often of interest to know whether, and how, allocation strategies can be optimized for the evolution of a structured population with randomness. In our
work, the investments represent different types of offspring, or alternative strategies for allocations to offspring. As payoffs we consider the long-term growth rate, the expected number
of descendants with some future discount factor, the extinction probability of the lineage, or the expected survival time. Two different kinds of population randomness are considered: demographic stochasticity and environmental stochasticity. In chapter 2, we solve the allocation problem w.r.t. the above payoff functions in three stochastic population models depending on different kinds of population randomness.
Evolution is often understood as an optimization problem, and there is a long tradition to look at evolutionary models from a variational perspective. In chapter 3, we deduce a variational characterization for the stochastic evolution of a structured population modeled by a
multitype Galton-Watson branching process. In particular, the so-called retrospective process plays an important role in the description of the equilibrium state used in the variational characterization. We define the retrospective process associated with a multitype Galton-Watson
branching process and identify it with the mutation process describing the type evolution along typical lineages of the multitype Galton-Watson branching process.
Continuous approximation of branching processes is of both practical and theoretical interest. However, to our knowledge, there is no literature on approximation of multitype branching processes in random environments. In chapter 4, we firstly construct a multitype Markov
branching process in a random environment. When conditioned on the random environment, we deduce the Kolmogorov equations and the mean matrix for the conditioned branching process. Then we introduce a parallel mutation-selection Markov branching process in a random
environment and analyze its instability property. Finally, we deduce a weak convergence result for a sequence of the parallel Markov branching processes in random environments and give
examples for applications.
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Gardner, Michael D. "Scan-Based Near-Field Acoustical Holography on Partially Correlated Sources." Diss., CLICK HERE for online access, 2009. http://contentdm.lib.byu.edu/ETD/image/etd3167.pdf.
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Hafiene, Yosra. "Continuum limits of evolution and variational problems on graphs." Thesis, Normandie, 2018. http://www.theses.fr/2018NORMC254/document.
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L’opérateur du p-Laplacien non local, l’équation d’évolution et la régularisation variationnelle associées régies par un noyau donné ont des applications dans divers domaines de la science et de l’ingénierie. En particulier, ils sont devenus des outils modernes pour le traitement massif des données (y compris les signaux, les images, la géométrie) et dans les tâches d’apprentissage automatique telles que la classification. En pratique, cependant, ces modèles sont implémentés sous forme discrète (en espace et en temps, ou en espace pour la régularisation variationnelle) comme approximation numérique d’un problème continu, où le noyau est remplacé par la matrice d’adjacence d’un graphe. Pourtant, peu de résultats sur la consistence de ces discrétisations sont disponibles. En particulier, il est largement ouvert de déterminer quand les solutions de l’équation d’évolution ou du problème variationnel des tâches basées sur des graphes convergent (dans un sens approprié) à mesure que le nombre de sommets augmente, vers un objet bien défini dans le domaine continu, et si oui, à quelle vitesse. Dans ce manuscrit, nous posons les bases pour aborder ces questions.En combinant des outils de la théorie des graphes, de l’analyse convexe, de la théorie des semi- groupes non linéaires et des équations d’évolution, nous interprétons rigoureusement la limite continue du problème d’évolution et du problème variationnel du p-Laplacien discrets sur graphes. Plus précisé- ment, nous considérons une suite de graphes (déterministes) convergeant vers un objet connu sous le nom de graphon. Si les problèmes d’évolution et variationnel associés au p-Laplacien continu non local sont discrétisés de manière appropriée sur cette suite de graphes, nous montrons que la suite des solutions des problèmes discrets converge vers la solution du problème continu régi par le graphon, lorsque le nombre de sommets tend vers l’infini. Ce faisant, nous fournissons des bornes d’erreur/consistance.Cela permet à son tour d’établir les taux de convergence pour différents modèles de graphes. En parti- culier, nous mettons en exergue le rôle de la géométrie/régularité des graphons. Pour les séquences de graphes aléatoires, en utilisant des inégalités de déviation (concentration), nous fournissons des taux de convergence nonasymptotiques en probabilité et présentons les différents régimes en fonction de p, de la régularité du graphon et des données initialesThe non-local p-Laplacian operator, the associated evolution equation and variational regularization, governed by a given kernel, have applications in various areas of science and engineering. In particular, they are modern tools for massive data processing (including signals, images, geometry), and machine learning tasks such as classification. In practice, however, these models are implemented in discrete form (in space and time, or in space for variational regularization) as a numerical approximation to a continuous problem, where the kernel is replaced by an adjacency matrix of a graph. Yet, few results on the consistency of these discretization are available. In particular it is largely open to determine when do the solutions of either the evolution equation or the variational problem of graph-based tasks converge (in an appropriate sense), as the number of vertices increases, to a well-defined object in the continuum setting, and if yes, at which rate. In this manuscript, we lay the foundations to address these questions.Combining tools from graph theory, convex analysis, nonlinear semigroup theory and evolution equa- tions, we give a rigorous interpretation to the continuous limit of the discrete nonlocal p-Laplacian evolution and variational problems on graphs. More specifically, we consider a sequence of (determin- istic) graphs converging to a so-called limit object known as the graphon. If the continuous p-Laplacian evolution and variational problems are properly discretized on this graph sequence, we prove that the solutions of the sequence of discrete problems converge to the solution of the continuous problem governed by the graphon, as the number of graph vertices grows to infinity. Along the way, we provide a consistency/error bounds. In turn, this allows to establish the convergence rates for different graph models. In particular, we highlight the role of the graphon geometry/regularity. For random graph se- quences, using sharp deviation inequalities, we deliver nonasymptotic convergence rates in probability and exhibit the different regimes depending on p, the regularity of the graphon and the initial data
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Turski, Jacek. "Calculus of variations for discontinous fields and its applications to selected topics in continuum mechanics." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=72804.
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Burchett, Woodrow. "Improving the Computational Efficiency in Bayesian Fitting of Cormack-Jolly-Seber Models with Individual, Continuous, Time-Varying Covariates." UKnowledge, 2017. http://uknowledge.uky.edu/statistics_etds/27.
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The extension of the CJS model to include individual, continuous, time-varying covariates relies on the estimation of covariate values on occasions on which individuals were not captured. Fitting this model in a Bayesian framework typically involves the implementation of a Markov chain Monte Carlo (MCMC) algorithm, such as a Gibbs sampler, to sample from the posterior distribution. For large data sets with many missing covariate values that must be estimated, this creates a computational issue, as each iteration of the MCMC algorithm requires sampling from the full conditional distributions of each missing covariate value. This dissertation examines two solutions to address this problem. First, I explore variational Bayesian algorithms, which derive inference from an approximation to the posterior distribution that can be fit quickly in many complex problems. Second, I consider an alternative approximation to the posterior distribution derived by truncating the individual capture histories in order to reduce the number of missing covariates that must be updated during the MCMC sampling algorithm. In both cases, the increased computational efficiency comes at the cost of producing approximate inferences. The variational Bayesian algorithms generally do not estimate the posterior variance very accurately and do not directly address the issues with estimating many missing covariate values. Meanwhile, the truncated CJS model provides a more significant improvement in computational efficiency while inflating the posterior variance as a result of discarding some of the data. Both approaches are evaluated via simulation studies and a large mark-recapture data set consisting of cliff swallow weights and capture histories.
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Italia, Magali. "Variation et variétés morphosyntaxiques du français parlé au Gabon." Phd thesis, Université de Provence - Aix-Marseille I, 2011. http://tel.archives-ouvertes.fr/tel-00787612.
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La thèse consiste en une comparaison entre deux types de français parlé par des locuteurs gabonais ayant le français comme langue seconde (d'ailleurs unique langue officielle du Gabon) : des locuteurs âgés et peu ou non scolarisés et des jeunes gens entre 17 et 25 ans, avec un niveau scolaire de troisième. La différence du nombre d'années de scolarisation des locuteurs induirait des compétences différentes en langue française. Le niveau sociolinguistique conditionnerait le niveau linguistique des locuteurs, ce qui les classerait dans des catégories clivées et imperméables, aux pôles inférieur et médian, selon la répartition sociolinguistique des locuteurs communément admise. Cette comparaison étudiée à partir de la morphologie du verbe et de l'utilisation du matériau morphologique à travers les concepts de personne, d'époque et d'aspect va permettre de vérifier cette hypothèse. Elle mettra également en avant les différentes variétés de français en présence, rendra compte du degré de la variation du français pour chaque locuteur et tentera d'établir des liens linguistiques entre les locuteurs sur le continuum linguistique.
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Hastie, Adam. "Large scale spatio-temporal variation of carbon fluxes along the land-ocean continuum in three hotspot regions." Doctoral thesis, Universite Libre de Bruxelles, 2019. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/287934.
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Previous research has shown a close relationship between the terrestrial and aquatic carbon (C) cycles, namely that part of the C fixed via terrestrial net primary production (NPP) is exported to inland waters. In turn, it has been demonstrated that once in the freshwater system C can not only be transported laterally as dissolved organic carbon (DOC), particulate organic carbon (POC) and dissolved inorganic carbon (DIC) but is also mineralized and evaded back to the atmosphere as CO2, or buried in sediments. A number of hotspot areas of aquatic CO2 evasion have been identified but there are considerable gaps in our knowledge, particularly associated with understanding and accounting for the temporal and spatial variation of aquatic C fluxes at regional to global scales, which we know from local scale studies, to be substantial. In this thesis, three important regional hotspots of LOAC activity were identified, where significant gaps in our understanding remain.For the boreal region, an empirical model is developed to produce the first high resolution maps of boreal lake pCO2 and CO2 evasion, providing a new estimate for total evasion from boreal lakes of 189 (74–347) Tg C yr-1, which is more than double the previous best estimate. The model is also used along with future projections of terrestrial NPP and precipitation, to predict future lake CO2 evasion under future climate change and land-use scenarios, and it is found that even under the most conservative scenario CO2 evasion from boreal lakes may increase 38% by 2100. For the Amazon Basin, the ORCHILEAK land surface model driven by a newly developed wetland forcing file, is used to show that the export of C to and CO2 evasion from inland waters is highly interannually variable; greatest during wet years and lowest during droughts. However, at the same time overall net ecosystem productivity (NEP) and C sequestration is highest during wet years, partly due to reduced decomposition rates in water-logged floodplain soils. Furthermore, it is shown that aquatic C fluxes display greater variation than terrestrial C fluxes, and that this variation significantly dampens the interannual variability in NEP of the Amazon basin by moderating terrestrial variation. Finally, ORCHILEAK is applied to the Congo Basin to investigate the evolution of the integrated aquatic and terrestrial C fluxes from 1861 to the present day, and in turn to 2099 under a future climate and land-use scenario. It is shown that terrestrial and aquatic fluxes increase substantially over time, both over the historical period and into the future, and that these increases are largely driven by atmospheric CO2. The proportion of terrestrial NPP lost to the LOAC also rises from 3% in 1861 to 5% in 2099 and this trend is driven not only by atmospheric CO2 but also by climate change. This is in contrast to the boreal region where the proportion of NPP exported to inland waters is predicted to remain relatively constant, and to the Amazon, where a decrease has been predicted, due to differences in projected climate change.L’état de l’art dans le domaine a montré qu’il y avait un lien étroit entre les cycles du carbone terrestre et aquatique :en effet, une partie du carbone fixé par photosynthèse (productivité primaire brute) est transférée vers les milieux aquatiques continentaux pour être ensuite transporté latéralement sous forme de carbone organique dissous (COD), de carbone organique particulaire (COP), de carbone inorganique dissous (CID). Durant ce transfert latéral, le carbone peut être minéralisé puis réémis vers l’atmosphère sous forme de CO2 ou enfoui dans les sédiments. Cependant, nous sommes encore loin de bien comprendre et surtout de quantifier les variations temporelles et spatiales des flux de carbones à l’échelle régionale et globale, même si les études faites à l’échelle locale nous montrent qu’elles sont importantes. Au cours de cette thèse, nous nous sommes focalisés sur 3 grandes régions pour lesquelles la connaissance des flux de carbone le long du continuum aquatique reliant les écosystèmes terrestres aux océans étaient encore très parcellaire.Pour la région boréale, un modèle empirique a été développé afin de produire les premières cartes à haute résolution de pCO2 et d’émission de CO2 pour les lacs boréaux. Les résultats du modèle nous ont permis de contraindre les émissions totales de CO2 pour les lacs boréaux à 189 (74-347) Tg C an-1, soit plus du double des estimations précédentes. Ce modèle a ensuite été couplé aux projections de production primaire brute terrestre et de précipitations afin de prédire les émissions de CO2 pour ces lacs pour différents scénarios de changement climatique et d’occupation des sols. Les résultats montrent que même en prenant le scénario le plus conservatif, les émissions de CO2 des lacs boréaux augmenteraient de 38% d’ici 2100.Pour le bassin de l’Amazone, le modèle d’écosystème terrestre ORCHILEAK, paramétré par de nouvelles donnés de forçage des zones humides, a été utilisé pour démontrer que l’export de carbone terrestre vers les réseaux fluviaux ainsi que les émissions de CO2 ont une très grande variabilité interannuelle :émissions élevées lors des années à forte précipitation et basses lors des années sèches. Cependant, la productivité nette de l’écosystème (PNE) Amazone et la fixation nette de carbone à l’échelle du bassin sont plus élevées lors des années humides, en partie dû au taux de décomposition de carbone organique réduit lorsque les sols sont saturés en eau. De plus, les résultats montrent que les flux de carbone des systèmes aquatiques ont une plus grande variabilité que les flux terrestres, ce qui atténue considérablement la variabilité interannuelle de la PNE du bassin de l'Amazone.Pour finir, nous avons appliqué ORCHILEAK au bassin du Congo afin d’étudier l’évolution intégrée des flux de carbone terrestres et aquatiques de 1861 à nos jours, ainsi que de projeter leur devenir au cours du 21eme siècle selon les scénarios de changement climatiques et de changement d’occupation des sols. Nous avons montré que les flux terrestres et aquatiques augmentent de façon significative durant la période historique et dans le futur, cette augmentation étant largement induite par l’augmentation du CO2 atmosphérique et, dans une moindre mesure, par le changement climatique. En particulier, la proportion de la productivité primaire brute terrestre exportée vers le continuum aquatique passe de 3% en 1861 à 5% en 2099. Ce résultat contraste avec ceux obtenu pour la région boréale où cette proportion reste relativement constante et pour l’Amazone où c’est une baisse qui est en fait prédite. Ces différences s’expliquent par des trajectoires de changement climatique distinctes pour ces 3 régions.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
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Hellström, K. (Kalle). "Variation in grazing tolerance and restoration of meadow plant communities." Doctoral thesis, University of Oulu, 2004. http://urn.fi/urn:isbn:9514274938.
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Abstract The area of traditionally managed semi-natural meadows is declining throughout Europe. Knowledge of how to restore their species richness is urgently needed. Community manipulations by means of grazing and mowing and, on the other hand, knowledge of species-level responses as well as the responses of functional plant groups to management may help in planning appropriate restoration tools. The restoration of species richness was studied in two community-level experiments: in a sheep grazing experiment and in a mowing experiment. Three species-level studies were conducted to test the compensatory capacity of monocarpic, herbaceous plants (Gentianella amarella, Erysimum strictum, Euphrasia stricta) to simulated herbivory (10–50% of stem being cut). The perennial Linaria vulgaris was used to study whether there is any benefit of clonal integration in the tolerance of simulated herbivory. This topic was studied in a growth experiment and a 13C tracer study. In both grazing and mowing experiments, small herbs gained more space, while the dominant tall herbs subsided. The species number increased by 30% on the grazed plots, but mowing did not affect species richness, probably indicating seed limitation. At sites of this kind, seed addition could be used to promote restoration. Functional plant groups appeared to be useful in predicting the effects of grazing on plant communities. Early season grazing and mowing seem to be proper management tools in overgrown/degraded meadows. In species-level studies, all the species had relatively good compensatory capacity to repair small damage. Overcompensation was observed in response to apical damage, especially when the growing conditions were favourable, supporting the compensatory continuum hypothesis. The studied monocarpic plant species may share a common unbranched growth form where incidental apical damage leads to activation of uninitialized meristems and slight overcompensation. These responses may represent consequences of adaptation to above-ground competition, rather than adaptation to predictable herbivory. In Linaria, damaged ramets were not supported, but the neighbouring ramets seemed to compete with each other for root resources. While growing in disturbed habitats, it is more profitable for this species to invest in new ramets. The present studies showed that, while the appearance and structure of a traditional grassland rich in small-growing herbs can be restored in five years, it is more difficult to increase species diversity by mere mowing or grazing. Knowledge of the tolerance of individual species for herbivory could provide useful information for planning management practices. More studies on the effects of different management tools on different meadow types are urgently needed for the maintenance of the diversity of these valuable environmentsTiivistelmä Perinteisellä tavalla hoidettujen luonnonniittyjen pinta-ala vähenee kaikkialla Euroopassa. Tarvitsemme enemmän tietoa siitä, miten näiden elinympäristöjen lajiston monimuotoisuus voitaisiin turvata. Tietämys laidunnuksen ja niiton vaikutuksesta kasviyhteisöihin ja toisaalta yksittäisiin kasvilajeihin tai toiminnallisiin kasviryhmiin voi auttaa tehokkaiden hoito- ja ennallistamistapojen löytämisessä. Tässä työssä tutkittiin niittyjen lajirikkauden palauttamista kahdessa yhteisötason kokeessa: lammaslaidunkokeessa ja kokeessa, jossa eri niittotapojen vaikutuksia selvitettiin. Kolmessa lajitason kokeessa testattiin monokarppisten ruohokasvien (rantaukonnauris, horkkakatkero, ketosilmäruoho) kompensaatiokykyä simuloituun herbivoriaan (10–50 % varresta poistettiin). Monivuotista kannusruohoa käytettiin tutkittaessa onko klonaalisesta integraatiosta hyötyä herbivorian siedossa. Tätä selvitettiin kasvukokeella ja hiili-13-merkkiainekokeella. Sekä laidun- että niittokokeessa matalat ruohokasvit saivat kasvutilaa korkeiden ruohojen valta-aseman vähentyessä. Laidunnus lisäsi lajimäärää 30 % koealaa kohti, mutta niitto ei vaikuttanut lajirikkauteen. Molemmissa kokeissa kasviyhteisö oli luultavasti siemenrajoitteinen. Tällaisissa kohteissa siementen lisäystä voitaisiin käyttää ennallistamiskeinona. Toiminnalliset kasviryhmät olivat käyttökelpoisia ennustettaessa laidunnuksen vaikutuksia kasviyhteisöön. Aikaisin kasvukaudella tapahtuva niitto/laidunnus näyttää sopivalta hoitokeinolta umpeenkasvaneilla niityillä. Lajitason kokeissa kaikki tutkitut kasvilajit kykenivät melko hyvin kompensoimaan vähäisiä vaurioita. Ylikompensaatiota havaittiin vasteena kärkivaurioihin erityisesti, kun kasvuolot olivat edulliset. Tämä tuki ns. kompensaatiojatkumohypoteesiä. Tutkituilla lajeilla voi olla yhtenäinen haaraton kasvumuoto, jossa ajoittaiset kärkivauriot johtavat lepotilassa olevien silmujen aktivoitumiseen ja lievään ylikompensaatioon. Nämä vasteet voivat olla seurausta sopeutumisesta valokilpailuun pikemmin kuin sopeutumisesta ennustettavissa olevaan herbivoriaan. Kannusruoholla vaurioituneita versoja ei autettu, vaan kloonin sisällä versot näyttävät kilpailevan keskenään juuriresursseista. Koska laji kasvaa häirityillä paikoilla, sille näyttää olevan edullisempaa investoida uusiin versoihin. Tämä työ osoitti, että vaikka perinteisen matalakasvuisen lajirikkaan niityn ulkonäkö ja rakenne voidaan palauttaa viidessä vuodessa, on vaikeampaa lisätä lajirikkautta pelkän niiton tai laidunnuksen avulla. Tietämys yksittäisten kasvilajien vasteista biomassan menetykseen voi auttaa sopivien hoitotapojen suunnittelussa. Lisää kokeita eri hoitotapojen vaikutuksista ja eri niittytyypeillä tarvitaan pikaisesti näiden arvokkaiden elinympäristöjen monimuotoisuuden ylläpitämiseksi
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Nayak, Soumya Sambit. "Continuum Analytical Shape Sensitivity Analysis of 1-D Elastic Bar." Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/101764.
Full textAbstract:
In this thesis, a continuum sensitivity analysis method is presented for calculation of shape sensitivities of an elastic bar. The governing differential equations and boundary conditions for the elastic bar are differentiated with respect to the shape design parameter to derive the continuum sensitivity equations. The continuum sensitivity equations are linear ordinary differential equations in terms of local or material shape design derivatives, otherwise known as shape sensitivities. One of the novelties of this work is the derivation of three variational formulations for obtaining shape sensitivities, one in terms of the local sensitivity and two in terms of the material sensitivity. These derivations involve evaluating (a) the variational form of the continuum sensitivity equations, or (b) the sensitivity of the variational form of the analysis equations. We demonstrate their implementation for various combinations of design velocity and global basis functions. These variational formulations are further solved using finite element analysis. The order of convergence of each variational formulation is determined by comparing the sensitivity solutions with the exact solutions for analytical test cases. This research focusses on 1-D structural equations. In future work, the three variational formulations can be derived for 2-D and 3-D structural and fluid domains.Master of Science
When solving an optimization problem, the extreme value of the performance metric of interest is calculated by tuning the values of the design variables. Some optimization problems involve shape change as one of the design variables. Change in shape leads to change in the boundary locations. This leads to a change in the domain definition and the boundary conditions. We consider a 1-D structural element, an elastic bar, for this study. Subsequently, we demonstrate a method for calculating the sensitivity of solution (e.g. displacement at a point) to change in the shape (length for 1-D case) of the elastic bar. These sensitivities, known as shape sensitivities, are critical for design optimization problems. We make use of continuum analytical shape sensitivity analysis to derive three variational formulations to compute these shape sensitivities. The accuracy and convergence of solutions is verified using a finite element analysis code. In future, the approach can be extended to multi-dimensional structural and fluid domain problems.
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Paccapeli, Roberto. "Control of mechanical system in smart structures : variational approaches for detecting damage." Paris 6, 2011. http://www.theses.fr/2011PA066640.
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L'objectif de ce travail est de développer des techniques de contrôle appliées aux structures électromécaniques, qui incluent éléments piézoéletriques utilisés comme actionneurs et capteurs. Les dispositifs faisant appel à un couplage piezoélectromécanique peuvent ameliorer les performances dynamiques des milieus et des éléments structurels et, donc, ils peuvent adapter eux-mêmes aux excitations externes. Comme la fonction de Lagrange associée au système mècanique est elle-même stable, la stratègie passive (i. E. Le circuit relié aux éléments piézoélectriques est constitué de composants passifs), est adoptée pour ne requérir ni énergie, ni engendrer des instabilitées. Les études proposés sont limités au cas des petites déplacements. Les modèles mathématiques des poutres de Timoshenko-Euler-Bernoulli sont considerés avec forme curviligne et des techniques de optimisation sont utilisées pour concevoir contrôleurs électrique couplés, capables de évaluter en temps réel la qualité du prototype. Ensuite, le flux de energie pour les systèmes des poutres rectilignes des types Timoshenko et Euler-Bernoulli avec point de discontinuité est utilisé pour comprendre les transferts d'énergie et l'influence des constraints. La modélisation d'un système électromécanique innovatif est proposée et les paramètres électriques sont optimisées pour modifier les coefficients de trasmission et de reflection. À la fin de la Thèse, on étudie la transmission et le rayonnement acoustique de plaque mince par l'utilisation de une catégorie particulière de dispositifs piézoélectriques faisant appel à des shunts. Ces circuits avec des résistances électriques et accordés sur les modes de vibration dissiperant la puissance par effet Joule. La position de les patches piezoeletriques est determiné par une nouvelle "utility function", Acoustic Controllability (AC). La fonctionne AC permet de placer des patches là où la déformation est maximale pour les modes de vibration à réduire. Donc la stratégies est de accorder des shunts résonants sur les modes de vibration avec hauts valeurs de "coefficient de efficacité". Les results expérimentales obtenus par une plaque d'aluminium fixée à deux côtés extérieurs et couplée à la tension et au courant dans un circuit électrique localisé, confirment la validité de la novelle technique proposée. Présenté
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Lafortune, Frantz-Daniel. "Sur l'origine des variations lentes liées au CO₂ de l'EEG en courant direct : implication de la barrière hémato-encéphalique." Master's thesis, Université Laval, 2010. http://hdl.handle.net/20.500.11794/22167.
Full textAbstract:
Ce mémoire de maîtrise soutient la thèse originale selon laquelle les déviations lentes du potentiel de courant direct (DC) liées au CO₂ et enregistrées au moyen de l'électroencéphalogramme (EEG) prennent source à travers l'interface ionique de la barrière hémato-encéphalique (BHE). Les circuits corticaux neuronaux ont longtemps été considérés comme étant les générateurs quasi exclusifs de l'ensemble de l'activité électrique constituant le signal électroencéphalographique. Des études ont démontré la contribution des cellules gliales comme source alternative de courant électrique participant, entre autres, aux décharges épileptiques et au sommeil. Or, plusieurs chercheurs suggèrent que les variations lentes du potentiel de l'EEG enregistrées en DC et modulées en fonction de la pression partielle du CO₂ (pCO₂) sont issues de l'interface entre le liquide céphalorachidien (LCR) et le sang que constitue la BHE. Considérant les trois hypothèses mécanistiques susmentionnées, il devient essentiel d'élucider la contribution relative des générateurs électriques neuronaux et gliaux par rapport à l'interface de la BHE en ce qui a trait à la genèse des déviations lentes DC de l'EEG. Nous avons donc procédé à cette étude par l'entremise d'enregistrements épicrâniens, épiduraux, épicorticaux, intraventriculaires et intraparenchymateux (c.-à-d. intraneuronaux, intragliaux et les potentiels de champ) sur des chats anesthésies à la kétamine-xylazine. Les variations du potentiel DC ont été induites via la modulation des paramètres ventilatoires des chats anesthésies, causant ainsi des changements du CO₂ de 11 l'ordre de 2 à 5 % en fin d'expiration. L'hypercapnie était invariablement associée à des déviations négatives du potentiel DC de l'EEG (déviation moyenne de -284.4 uV/C02 %, intervalle allant de -216 à -324 pV/C02%), tandis que l'hypocapnie provoquait des déviations positives (déviation moyenne de l'ordre de 307.8 uV/C02 %, intervalle allant de 234 à 342 ^V/C02%), et ce, dans toutes les électrodes d'enregistrement. L'hypocapnie a provoqué une augmentation significative de la pression intracrânienne, tandis que l'hypercapnie ne l'a diminué que très légèrement. La rupture de la barrière hématoencéphalique a entraîné une déviation positive du potentiel DC et a réduit drastiquement les réponses subséquentes du potentiel DC à l'hypo-hypercapnie. Le thiopental et l'isoflurane ont aussi provoqué une déviation positive du potentiel DC reliée à la dose administrée, tandis qu'à des concentrations plus élevées, les réponses à l'hypo-/hypercapnie présentaient une polarité inversée. Pour ce qui est de la possible implication des neurones dans la production des déviations du potentiel DC, aucune inversion de polarité n'a été enregistrée entre le scalp, les diverses couches intracorticales et les structures profondes du cerveau. De plus, le potentiel de membrane des neurones et des glies n'a pas montré de variation significative ou systématique en association lors des déviations du potentiel DC liées au CO₂. Durant les crises épileptiques de type "pointe-onde", l'activité pathologique des neurones s'est accompagnée de déviations du potentiel DC d'amplitude significativement moins élevée que celles générées par hyper-/hypocapnie. Enfin, des déviations du potentiel DC étaient encore observées lors même de la quiescence des circuits neuronaux associée à l'état de burst-suppression du tracé électroencéphalographique induit par l'anesthésie. Nous soutenons donc la thèse selon laquelle les potentiels générés à travers la BHE sont la source principale des variations épi-corticales/crâniennes du potentiel DC de l'EEG enregistré à l'EEG dans des conditions qui affectent le pH du cerveau et/ou la circulation sanguine cérébrale.
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Peukert, Sabine. "Understanding the effects of different grassland management practices on the soil-to-water transfer continuum." Thesis, University of Exeter, 2014. http://hdl.handle.net/10871/16687.
Full textAbstract:
One of the major challenges for agriculture today is to manage soil properties and their spatial distribution to optimize productivity and minimize environmental impacts, such as diffuse pollution. To identify best management practices, the effects of different agricultural management practices on pollutant sources, mobilization, transfer and delivery to water bodies need to be understood. Grasslands managed for dairy and meat production, despite being widespread, have received less research attention than other agricultural land uses. Therefore, this thesis studies the effects of different grassland management practices on soil properties and their spatial distribution and the mobilization and delivery of multiple diffuse pollutants. As a grassland case study, monitoring for this thesis was conducted across three fields (6.5 – 7.5 ha) on the North Wyke Farm Platform, a grassland experimental farm in the UK. First, the effects of permanent grassland management (permanent for at least 6 years, but different grassland management > 6 years ago) were characterized as a baseline, followed by quantifying the short-term effects of ploughing and reseeding of permanent grassland fields. Throughout those management periods, i) a range of soil physical (bulk density [BD]) and chemical (soil organic matter [SOM], total N [TN], total phosphorus [TP], total carbon [TC]) soil properties and their spatial distribution were sampled and analysed by geostatistics, and ii) hydrological characteristics and multiple pollutant fluxes (suspended sediment [SS] and the macronutrients: total oxidized nitrogen-N [TONN], total phosphorus [TP], and total carbon [TC]) were monitored at high temporal resolution (monitoring up to every 15 minutes). The permanent grassland fields (or areas within fields) can be considered to be functioning differently. Past management legacy (more than 6 years ago) has affected soil properties and their distribution with subsequent effects on sediment and macronutrient delivery from the fields to surface waters. Overall, permanent grasslands were found to contribute significantly to agricultural diffuse pollution. The estimated erosion and macronutrient losses were similar to or exceeded the losses reported for other grasslands, mixed land use and even arable sites, and sediment and TP concentrations exceeded those recommended by EU / UK water quality guidelines. Ploughing and reseeding did not homogenize spatial variation and did not override past management effects. Long-term management differences affected soil properties and altered soil processes, so that the fields subsequently responded differently to ploughing and reseeding. All nutrient concentrations were significantly reduced in the older grassland field (no ploughing for 20 years), but not in the younger grassland field (no ploughing for 6 years). Ploughing and reseeding significantly accelerated the losses of sediment and macronutrients and sediment, TP and TONN exceedance frequencies of EU / UK water quality guidelines increased. Additionally, ploughing and reseeding caused a shift in the relative importance of nutrients, by increasing the relative importance of N. Such large sediment and nutrient losses from intensively managed grasslands should be acknowledged in land management guidelines and advice for future compliance with surface water quality standards. The between-field and within-field variation highlights the importance of baseline characterization and paired catchment studies. The long-term effects of management still acting on soil properties and subsequently water quality indicates how long it may take to see soil and water quality improvements after implementing mitigation measures. Therefore, long-term management history always has to be included when interpreting soil and water quality data.
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Scharff, Richard. "Design of Electricity Markets for Efficient Balancing of Wind Power Generation." Doctoral thesis, KTH, Elektriska energisystem, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-171063.
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Deploying wind power to a larger extent is one solution to reduce negative environmental impacts of electric power supply. However, various challenges are connected with increasing wind power penetration levels. From the perspective of transmission system operators, this includes balancing of varying as well as - to some extent - uncertain generation levels. From the perspective of power generating companies, changes in the generation mix will affect the market's merit order and, hence, their profits. This thesis focuses on provision and use of flexibility in the Nordic electricity market. First, this thesis studies wind power variations and accuracy of wind power forecasts in Sweden using statistical methods. Even though today’s wind penetration levels are still low in Sweden, power systems and electricity markets have to cope with these characteristics of variations and forecast errors to a larger extent in future. Second, it investigates to which extent an increased exchange and use of flexibility that is available in the intraday time-frame could efficiently facilitate system balancing and whether this would also be profitable from the power generating companies' perspective. Here, a simulation model is developed that reflects important aspects of production planning and trading decisions in the intraday time-frame. In a first case study, it is shown that the benefits of internal rescheduling strongly depend on the costs to adjust production plans in the intraday time-frame as compared to real-time. In a second case study, it becomes evident that trading flexibility in the intraday time-frame can reduce the need for system balancing more efficiently than internal rescheduling within each balance responsible party. Motivated by the positive gains of intraday trading and the challenge of appropriately modelling continuous intraday markets, trading activity and price development on Elbas is investigated. The results provide insights into trading behaviour on a continuous intraday market and show that trading is not always in accordance to the power system's physical situation. To the extent to which better information and adaptations in the market design could improve the market participants' base for trading decisions, policy recommendations and further research questions areas suggested.Att använda vindkraft i en större utsträckning är en möjlighet att minska elproduktionens negativa miljöpåverkan. Det finns dock också olika utmaningar med stora mängder vindkraft. Från ett systemperspektiv gäller det till exempel att hålla balansen mellan tillförsel och konsumtion av el. Från elproducenternas perspektiv bör vindkraftens påverkan på elmarknaden nämnas eftersom det påverka aktörernas vinster. Avhandlingen titta närmare in i hur man kan få tillgång till mer flexibilitet på produktionssidan. Avhandlingen består av tre delar. För det första undersöks variationer och prognosfel av vindkraft i Sverige med hjälp av statistiska metoder. Även om andel vindkraft hittills är låg i Sverige, behöver elsystemet och elmarknader i framtiden hantera samma egenskaper av själva variationer och prognosfel som idag men i en större utsträckning. För det andra undersöks hur den flexibiliteten som finns i tidshorisonten några timmar innan leveranstimmen kan utnyttjas för att integrera vindkraften på ett sätt som är både fördelaktigt från systemets och från aktörernas perspektiv. Undersökningen sker med hjälp av en simuleringsmodell som omfattar viktiga delar i produktionsplanering och intradayhandel. I en fallstudie uppvisas att vinster av intern omplanering är i högsta grad beroende på kostnadsskillnaden mellan omplanering några timmar innan leveranstimmen och anpassning av körscheman under själva leveranstimmen. Resultat av ytterligare en fallstudie uppvisar att det är betydligt billigare och mer effektivt att använda intradayhandel istället för intern omplanering för att utnyttja den befintliga flexibiliteten och för att reducera obalanser som systemoperatörer annars behöver ta hand om under leveranstimmen. Detta är en anledning till att undersöka handelsmönster på Elbas som är en intradaymarknad med kontinuerlig handel. En annan anledning till den här tredje delen är utmaningarna i att modellera kontinuerlig intradayhandel. Studien beskriver handelsaktiviteten på Elbas och hur priserna utvecklas under handelstiden. Ett resultat är att handeln inte alltid återspeglar den fysiska situationen i elsystemet. I den utsträckningen som ett snabbare informationsflöde och förändringar i marknadsdesignen kunde förbättrar aktörernas underlag för intradayhandel, föreslås förbättringar och öppna forskningsfrågor.
QC 20150911
Elektra 36141: Korttidsplanering av vatten-värmekraftsystem vid stora mängder vindkraft: System-perspektivet
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Della, Corte Alessandro. "Lattice structures with pivoted beams : Homogenization and nonlinear elasticity results." Thesis, Toulon, 2017. http://www.theses.fr/2017TOUL0019/document.
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Cette thèse est consacrée à la modélisation des structures fibreuses avec des milieuxcontinus généralisés. Dans l’Introduction, l'état de l'art concernant les milieuxcontinus généralisée et applications aux structures fibreuses sont décrits et lesproblèmes ouverts pertinents sont mis en évidence. Dans le Chapitre 1 et 2, uneprocédure d'homogénéisation rigoureuse basée sur des arguments de Gammaconvergenceest appliquée à une structure en treillis et à un model de poutrediscrétisé. Dans le Chapitre 3, un traitement variationnel est utilisé pour formuler unapproche favorable du point de vue numérique. Dans le Chapitre 4 sont discutées lesrésultats expérimentaux concernant le comportement de la structure dans différentstypes de déformation. Cela à motivé les études effectuées dans le Chapitre 5, ou lesMéthodes directes de calcul des variations sont appliquées à poutres d’Euler engrandes déformationsThis thesis focuses on the mathematical modeling of fibrous structures having somepeculiar properties (high strength-to-weight ratio and very good toughness infracture), whose mechanical behavior escapes from standard Cauchy elasticity. Inparticular, it addresses cases in which the presence of a microstructure, consisting ofregularly spaced pivoted beams, entails effects that are well described by generalizedcontinuum models, i.e. models in which the deformation energy density depends notonly on the gradient of the placement but also on the second (and possibly higher)gradients of it. In the Introduction, the state of the art concerning generalizedcontinua and their applications for the description of fibrous structures is describedand some relevant open problems are highlighted. In Chapter 1 and 2 a rigoroushomogenization procedure based on Gamma-convergence arguments is performedfor a lattice (truss-like) structure and for a discrete 1D system (Hencky-type beammodel). In Chapter 3, a variational treatment is employed to formulate acomputationally convenient approach. In Chapter 4 some experimental resultsconcerning the behavior of the structure in various kinds of deformation arediscussed. This motivated the investigation performed in Chapter 5, in which DirectMethods of Calculus of Variations are applied to Euler beams in large deformationsunder distributed load
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Zhou, Jianjun. "Contribution à la modélisation de l'endommagement anisotrope et de la variation de la perméabilité des roches fragiles." Lille 1, 2006. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2006/50376-2006-Zhou.pdf.
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Cette étude concerne une modélisation du comportement mécanique et hydromécanique des roches saturées avec la prise en compte de la variation de la perméabilité en fonction de l'endommagement. On établit d'abord la fonction de l'enthalpie libre par une approche micromécanique directe en prenant la distribution de la longueur de microfissure. On prend en compte l'ouverture de microfissures fermées liée au glissement tangentiel en raison de la rugosité des surfaces de fissures. Cette ouverture contribue directement à la dilatance volumique et à la variation de perméabilité macroscopique du matériau. On montre également une approche phénoménologique avec une approximation par un tenseur d'endommagement d'ordre deux. Ensuite on propose une extension du modèle à décrire le comportement poromécanique des roches saturées. Les réponses poromécanique en conditions drainées et non drainées du grès des Vosges ont été étudiées. Dans la dernière partie on a proposé un modèle couplé décrivant le comportement du couplage entre l'endommagement induit et la variation de la perméabilité des roches.
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FURTADO, Rennan. "Media??o did?tica de base colaborativa para o uso e estudo da referencia??o em formas acusativas na EJA: do stand-up ? reda??o escolar:." Universidade Federal Rural do Rio de Janeiro, 2017. https://tede.ufrrj.br/jspui/handle/jspui/2390.
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This work aims to develop a didactic mediation, of collaborative basis, for anaphoric direct objetcs study and use, from stand up comedy discursive genre, in groups of youngsters and adults who did not continue their studies and those who have not joined primary and/or elementary school at appropriate age. This is youth and adults education (EJA). The aim is to encourage student's participation in Portuguese classes, in public schools of the State of Rio de Janeiro (NEJA) assuming that the use of stand up comedy discursive genre would stimulate them to develop reading activities, textual production and reflection on linguistic uses, focusing on the study and use of anaphoric direct object. For this purpose, this research was based on Collaborative Learning Theory (BEHRENS, 2013), which enabled the organicity of mediation in order to promote a participatory education in which the interaction between student and teacher is the basis of the work. In addition, in linguistic theories we searched assumptions to justify the proposal. Namely: Referencing Theory (KOCH and ELIAS, 2012; CHAN, 2004) and the continuous variation of Linguistics (BORTONI-RICARDO, 2004, 2005), with emphasis on continuous orality-literacy. The first one allowed the understanding of anaphoric relations, especially the Anaphoric Direct Objetc one, in a text; the second one enabled the recognition that linguistic accomplishments, variables, such as those in this category, are in a continuous line rather than on opposite sides. We also keep this continuous association with the discursive genres continuous proposed by Marcuschi (2001). This work also aimed to achieve specific objectives in Portuguese classes just as teaching referral strategies in acusativess forms, as well as other more general like promoting discussion, the collectivity, the sharing of ideas and mutual respect between teacher and students.
Este trabalho tem por objetivo desenvolver uma media??o did?tica, de base colaborativa, para estudo e uso do objeto direto anaf?rico (ODA), a partir do g?nero discursivo stand-up comedy, em turmas de educa??o para jovens e adultos que n?o deram continuidade aos estudos e para os que n?o ingressaram no Ensino Fundamental e/ou M?dio com a idade apropriada. Trata-se do segmento Educa??o de Jovens e Adultos (EJA). Busca-se incentivar a participa??o, nas aulas de L?ngua Portuguesa, dos alunos inseridos nos cursos da Educa??o de Jovens e Adultos da rede p?blica do estado do Rio de Janeiro (NEJA), partindo-se da hip?tese de que o uso do referido g?nero os estimularia a desenvolver atividades de leitura, produ??o textual e reflex?o sobre usos lingu?sticos, com foco no estudo e uso do ODA. Para tanto, esta pesquisa baseou-se na Teoria Colaborativa de Aprendizagem (BEHRENS, 2013), que possibilitou a organicidade da media??o para promovermos um ensino participativo em que a intera??o entre aluno e professor constitui a base do trabalho. Al?m disso, buscamos, em teorias lingu?sticas, pressupostos para fundamenta??o da proposta. A saber: a teoria da Referencia??o (KOCH E ELIAS, 2012; CAVALCANTE, 2004) e a dos Cont?nuos de varia??o lingu?stica (BORTONI-RICARDO, 2004, 2005), com ?nfase no cont?nuo oralidade-letramento. A primeira permitiu o entendimento das rela??es anaf?ricas, sobretudo a do ODA, em um texto; a segunda possibilitou o reconhecimento de que as realiza??es lingu?sticas, as vari?veis, como as dessa categoria, situam-se em uma linha cont?nua e n?o em lados opostos. Procedemos ainda ? associa??o desse cont?nuo com o cont?nuo dos g?neros discursivos proposto por Marcuschi (2001). Este trabalho buscou, ainda, atingir objetivos espec?ficos da disciplina de L?ngua Portuguesa, como ensinar estrat?gias de referencia??o em formas acusativas, al?m de outros mais gerais, como promover o debate, a coletividade, o compartilhamento de ideias e o respeito m?tuo entre professor e alunos.
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Métivier, Laurent. "Influence des variations latérales de densité et de paramètres rhéologiques sur la déformation de la terre." Paris 7, 2004. http://www.theses.fr/2004PA077237.
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A l'heure du développement de la gravimétrie spatiale (satellites GRACE et GOCE), de nouveaux modèles de déformation gravito-élastique de la Terre deviennent indispensables. La Terre se déforme en chaque instant sous l'action de la Lune et du Soleil (la marée luni-solaire), et sous l'action des surcharges de surface engendrées par les enveloppes fluides de la planète (l'atmosphère, les océans et les eaux continentales). Actuellement, ces déformations élastiques sont modélisées en supposant la Terre comme un solide sphérique (ou ellipsoïdale) dont la structure interne est hydrostatique et à symétrie radiale. Or, la planète contient des variations latérales de densité et de paramètres rhéologiques, engendrées par sa dynamique interne, qui sont négligées dans ces modèles. Nous avons réalisé un nouveau modèle de déformation de la planète qui, pour la première fois, tient compte des variations latérales internes des paramètres physiques de la Terre, de son état de précontraintes non-hydrostatique et de ses topographies dynamiques aux interfaces de discontinuités. Ces aspects sont intégrés dans les équations de la gravito-élasticité utilisant la théorie des perturbations. Le système d'équations est résolu à l'aide d'une méthode numérique : les éléments spectraux associés au maillage de la "sphère cubique". Le modèle a été validé avec une bonne précision sur des problèmes géodynamiques connus. Nous avons dans ce but repris les travaux analytiques réalisés par Love concernant une Terre homogène incompressible. Nous nous consacrons ensuite à de premières applications. Nous réévaluons l'impact de l'ellipticité de la Terre sur sa réponse de marée solide, et sur sa réponse aux surcharges de surface. Nous prenons l'exemple de la surcharge de pression atmosphérique et son influence sur les variations zonales de la gravité (les coefficients J2 et J3). Enfin nous discutons des applications de ce modèle à la détermination de l'influence des méga-panaches mantelliques sur la réponse de marée et la réponse de surcharges de la TerreNowadays with the development of space gravimetry (GRACE and GOCE satellites), new elasto-gravity deformation models become essential. Earth is continuously deformed by the Sun and the Moon attraction (luni-solar tides), and under the action of surface loading due to external fluid layers (atmosphere, ocean and continental water). Presently these elastic deformations are modelized assuming that the Earth is a spherical solid (or ellipsoïdal) with a radially symmetrical hydrostatic structure. However, the internal dynamic of the planet induces lateral variations of density and rheological parameters that are neglected into these models. We built an Earth deformation model which, for the first time, takes into account the internal lateral variations of the planet physical parameters, its no-hydrostatic prestresses, and the dynamical topographies of its discontinuity interfaces. These particularities are integrated into the elasto-gravitational equations using the perturbation theory. The equation System is solved with a numerical method: the spectral element method associated to the "cubed sphere" mesh. The model has been validated on known geophysical problems with a good accuracy. With this aim, we recovered the Love analytical work concerning a homogeneous incompressible Earth. We then made first applications. We appraised the impact of Earth ellipticity on solid tides and on the Earth response to surface loadings. We took the example of the influence of atmospheric pressure on zonal gravity variations (J2 and J3 coefficients). Finally, we discuss the ability of the model to determine the influence of mantellic superplumes on the tidal response and the loading response of the Earth
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Drescher, Nils Alexander [Verfasser], Götz Silvester [Akademischer Betreuer] Uhrig, and Kai Phillip [Gutachter] Schmidt. "Variational and perturbative extensions of continuous unitary transformations for low-dimensional spin systems / Nils Alexander Drescher. Betreuer: Götz Silvester Uhrig. Gutachter: Kai Phillip Schmidt." Dortmund : Universitätsbibliothek Dortmund, 2014. http://d-nb.info/1101476842/34.
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Drescher, Nils [Verfasser], Götz Silvester [Akademischer Betreuer] Uhrig, and Kai Phillip [Gutachter] Schmidt. "Variational and perturbative extensions of continuous unitary transformations for low-dimensional spin systems / Nils Alexander Drescher. Betreuer: Götz Silvester Uhrig. Gutachter: Kai Phillip Schmidt." Dortmund : Universitätsbibliothek Dortmund, 2014. http://d-nb.info/1101476842/34.
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Mell, Hugo. "Fast-slow strategies in human populations : applying insights from life history theory to explain patterns of interindividual variation." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEE074.
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Des gradients sociaux ont été documentés pour une variété de comportements individuels. Au sein des pays occidentaux par exemple, les personnes ayant un statut socio-économique plus bas ont tendance à investir moins dans leur éducation, à fumer davantage, sont plus susceptibles de souffrir d'obésité et plus enclines à prendre des risques dans des contextes économiques. Ainsi, être exposé à des conditions de vie précaire semble engendrer une série de comportements, covariant de manière systématique. Ce syndrome comportemental a été principalement interprété comme le produit de déficits cognitifs ayant traits à la prise de décision et/ou à un manque de volonté. Dans ce manuscrit, nous explorons une approche différente, qui s'ancre dans les explications adaptationnistes des comportements humains. Au lieu d'appréhender les comportements observés chez les individus en situation de précarité comme des anomalies, ceux-ci sont perçus comme des ajustements des stratégies individuelles d'histoire de vie, adaptés à la vie dans des environnements précaires. En effet, nous approfondirons l'hypothèse selon laquelle un environnement précaire sélectionne des stratégies qui accordent davantage de poids aux bénéfices immédiats plutôt qu’aux investissements de long terme, affectant dès lors toute une gamme de comportements. Dans un premier temps, nous analyserons par le biais de modèles d'équations structurelles, différents jeux de données afin de mesurer le degré de covariation de comportements ayant trait à la reproduction, à l'investissement dans la santé et au niveau de confiance, ainsi que leur association éventuelle avec le niveau de précarité éprouvé pendant l'enfance ou à l'âge adulte. Globalement, nos résultats indiquent qu'une réduction de l’investissement dans la santé co-varie avec une stratégie de reproduction plus court-termiste, ainsi qu'un plus faible niveau de confiance. De plus, ce pattern est surreprésenté chez les personnes en situation de précarité, avec des effets persistants des conditions pendant l'enfance. En parallèle de ces travaux empiriques, nous nous sommes par ailleurs intéressés aux fondements théoriques de nos hypothèses de travail. Précisément, nous avons développé un modèle formel de stratégie d'histoire de vie prédisant les changements de préférences temporelles intra- et interindividuelles. Celui-ci nous a permis de mettre en évidence l’importance de deux facteurs distincts pour déterminer le degré optimal avec lequel des individus doivent préférer les récompenses de court-terme : 1) le niveau d'incertitude sur la probabilité de collecter une récompense délayée dans le temps, et 2) le coût d'opportunité à ne pas bénéficier de la récompense pendant la période de délai. Enfin, nous concluons ce travail en discutant des perspectives particulièrement intéressantes offertes par une intégration plus poussée de l'approche développée dans cette thèse, avec d'autres sciences sociales et sciences du comportement plus traditionnellesSocial gradients in behavior have been documented across various domains of people’s lives. In western countries, low SES individuals tend for instance to invest less in their education, to smoke more, are more subject to overweight and are more willing to take risks in financial settings. Being exposed to deprivation therefore seems to elicit a constellation of behaviors that appear to covary in a systematic fashion. This behavioral constellation of deprivation has been mostly interpreted as the product of poor decision making abilities, of a general failure of willpower. In this dissertation we explore a different interpretation that is rooted in adaptive explanations of human behavior. Instead of viewing the behaviors of low SES individuals as suboptimal deviations from a global optimum, they are seen as adjustments of people’s overall life strategies that are, from an evolutionary point of view, adaptive in the particular context of a deprived ecology. Indeed, we will explore the idea that deprived environments select for strategies that put more weight on present outcomes over uncertain future outcomes, and that this present orientation in low SES individuals propagates across a range of decision domains, giving rise to the constellation. To this aim, we first use structural equation models on observational data from a diversity of samples, to analyze the covariation between peoples’ behaviors in several relevant domains (health, reproduction, social trust) and their exposure to deprivation during childhood and/or adulthood. Overall, we find that a lower somatic effort tends to covary with a more short-term reproductive strategy, as well as lower social trust. This pattern is associated with a higher exposure to deprivation, with unique effects of early life conditions. In addition to this empirical work, we further investigate the theoretical underpinnings of our working hypotheses, from an adaptationist perspective. Specifically, we build a formal life history model to predict optimal changes in discounting within and between individuals. This allows us to highlight that the extent to which individuals prefer short-term rewards, should vary depending on two main parameters: 1) the uncertainty around their ability to actually collect delayed rewards, and 2) the opportunity costs of not having the reward during the delay. Finally, we conclude by discussing the promising perspective of further integrating the approach adopted in the present thesis, with more traditional social and behavioural sciences
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Ortigosa, Martinez Rogelio. "On a new variational and computational framework for polyconvex nonlinear continuum mechanics and convex multi-variable nonlinear electro-elasticity." Thesis, Swansea University, 2016. https://cronfa.swan.ac.uk/Record/cronfa34893.
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The world of smart materials has experienced a dramatic revolution in the last decades. Electro Active and Magneto Active Materials are some of the most iconic of these, among which, dielectric and magnetostrictive elastomers are becoming extremely popular due to their outstanding actuation capabilities, and in lesser degree, to their energy harvesting capabilities. A clear example illustrating these extraordinary capabilities has been reported in the experimental literature, which has shown unprecedented extreme electrically induced deformations for the most representative dielectric elastomer, namely the acrylic elastomer VHB 4910.This thesis is focused on the development of well-posed constitutive models for nonlinear electro-elasticity in scenarios characterised by extreme deformations and extreme electric fields. This fundamental objective represents the underlying ingredient for the novel variational and computational frameworks developed hereby in the context of electro-elasticity. Very remarkably, the similarity between the equations in both electro-elasticity and magneto-elasticity, enables the variational and computational frameworks developed to be extended to the latter scenario, characterised by magnetomechanical interactions. Despite the enormous interest of the experimental and computational scientific community, the definition of suitable constitutive models is still at its early stages for both electro and magneto active materials. In the more specic context of elasticity, considerable effort has been devoted to the denition of polyconvex energy functionals, which entail the most widely accepted constitutive restriction, namely the ellipticity or Legendre-Hadamard condition. This condition, strongly related to the material stability of the constitutive equations, ensures the well-posedness of the governing equations. An extension of the ellipticity condition to the context of nonlinear electro-elasticity and hence, magneto-elasticity, is proposed in this work, ensuring the well-posedness of the equations for the entire range of deformations and electric or magnetic fields. It is important to emphasise that in this work, the extension of the ellipticity condition to the field of electro-elasticity is exclusively based on material stability considerations. The energy functional encoding the constitutive response of the electro active material is defined according to a novel convex multi-variable representation in terms of an extended set of arguments which ensures material stability. The extended set of arguments, including those characterising the concept of polyconvexity in the more specic scenario of nonlinear elasticity, is further enriched with additional electromechanical entities. Unfortunately, proof of sequential weak lower semicontinuity of the proposed definition of multi-variable convexity is not provided in this work. This condition, and the additional requirement of appropriate coercivity conditions on the energy functional, would ensure the existence of minimisers. Nevertheless, although of extreme relevance and scientific interest, this topic is not in the scope of the thesis and could be the objective of further research.
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Vermeeren, Mats [Verfasser], Yuri B. [Akademischer Betreuer] Suris, Yuri B. [Gutachter] Suris, Christian [Gutachter] Lubich, and Frank W. [Gutachter] Nijhoff. "Continuum limits of variational systems / Mats Vermeeren ; Gutachter: Yuri B. Suris, Christian Lubich, Frank W. Nijhoff ; Betreuer: Yuri B. Suris." Berlin : Technische Universität Berlin, 2018. http://d-nb.info/1174251263/34.
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Zabiba, Mohammed. "Variational approximation of interface energies and applications." Thesis, Avignon, 2017. http://www.theses.fr/2017AVIG0419/document.
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Les problèmes de partition minimale consistent à déterminer une partition d’un domaine en un nombre donné de composantes de manière à minimiser un critère géométrique. Dans les champs d’application tels que le traitement d’images et la mécanique des milieux continus, il est courant d’incorporer dans cet objectif une énergie d’interface qui prend en compte les longueurs des interfaces entre composantes. Ce travail est focalisé sur le traitement théorique et numérique de problèmes de partition minimale avec énergie d’interface. L’approche considérée est basée sur une approximation par Gamma-convergence et des techniques de dualitéMinimal partition problems consist in finding a partition of a domain into a given number of components in order to minimize a geometric criterion. In applicative fields such as image processing or continuum mechanics, it is standard to incorporate in this objective an interface energy that accounts for the lengths of the interfaces between components. The present work is focused on thetheoretical and numerical treatment of minimal partition problems with interface energies. The considered approach is based on a Gamma-convergence approximation and duality techniques
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Dalu, Tatenda. "Spatio-temporal variation in the phytobenthos and phytoplankton community structure and composition of particulate matter along a river-estuary continuum assessed using microscopic and stable isotope analyses." Thesis, Rhodes University, 2015. http://hdl.handle.net/10962/54416.
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Phytoplankton and phytobenthos communities play an important role in lotic systems as primary producers providing essential biomolecules to higher trophic oganisms and are important indicators for environmental or ecological change. In this thesis, field studies (observational and experimental) along a river–estuary continuum were conducted to assess the spatio-temporal variation and development of phytobenthos and phytoplankton communities using a combination of stable isotope and community analyses in a temperate southern African system across four study periods: September (early spring) and November/December (late spring) 2012, and February (summer) and May/June (winter) 2013. Additionally, the sources and composition of the particulate organic matter were also analysed using stable isotope (δ15N and δ13C) analysis. The effects of substrate type and flood occurrence were assessed through experimental studies at an up- and downstream site of the river after a major flood event that occurred between October and November 2012. Common household tiles were used as artificial substrates to study the development/succession of phytobenthos communities after the flood disturbance. Distinct diatom communities were observed between upstream and downstream sites and at each site, community structure changed with time indicating succession. In addition to recording diatom characteristics on three natural substrates, namely; macrophytes, rocks and sediment, artificial substrates observations were also made on three different types of artificial substrates, namely; brick, brown clay and grey clay tiles. The natural (species richness 78) and artificial substrates (sp. richness 93) had different communities with the latter having greater species richness. Common phytobenthos taxa were not restricted to a single substrate but preference was generally high for the artificial substrates, especially brown tiles (mean sp. richness 47). Results of the redundancy analysis (RDA) analysis indicated that ammonium, conductivity, total dissolved solids, salinity, pH, oxygen reduction potential, phosphate and water depth were the major determinants of the phytobenthos composition at the two sites. The spatio–temporal variation of phytoplankton and phytobenthos communities and allochthonous organic matter along the river–estuary continuum was assessed at 8 sites using a combination of community and stable isotope analyses. A total of 178 species belonging to 78 genera were recorded with diatoms being predominant, accounting for 81.9 % of the total abundance. The total chl-a concentration along the river-estuary continuum increased from spring to a high in summer before decreasing to a low in winter. Periphyton communities were observed to be significantly different across sites (p < 0.05) in terms of species richness, abundances and isotopically The high periphytic δ15N values (range 7.9–15.2 ‰) recorded at the downstream sites compared to the pristine upstream sites (δ15N values range 4–7 ‰) suggest nutrient enrichment most likely derived from anthropogenic sources. Overall, our results reveal general patterns of periphyton communities and stable isotopes and provide improved information in the use of periphyton δ15N as an excellent indicator of anthropogenic nitrogen pollution. Ecologists are interested in the factors that control, and the variability in, the contributions of different sources to mixed organic materials traveling through lotic systems. We hypothesized that the source matter fuelling mixed organic pools in a river-estuary continuum varies over space and time, with the upper reaches of a system characterized by allochthonous-dominated material and autochthonous contributions becoming more important in the lower reaches. Samples of the mixed organic pools and allochthonous and autochthonous source materials were collected during the four study periods. The C:N ratios of suspended particulate matter (SPM) collected during summer and winter indicated that the lower reaches of the system had similar organic matter contributions from the freshwater and terrestrial sources. Stable isotope analysis in R revealed that the contributions of autochthonous organic matter were high in SPM along the entire continuum, and aquatic macrophytes were significant contributors to SPM specifically in the upper reaches. The terrestrial leaves made major contributions to the SPM in the middle regions of the system (i.e. downstream sites of the river, particularly in early and late spring). Bulk detritus had large allochthonous matter components in the lower reaches (estuary), and the contributions of aquatic macrophytes and benthic algae to bulk detritus were high (> 50 %) in the upper to middle reaches (river), but low (< 20 %) in the lower reaches (estuary). The current investigation represents the first attempt to assess the validity of the River Continuum Concept (RCC) in a southern African temperate river. The phytoplankton and phytobenthos communities, and chl-a concentration followed a trend similar to that proposed for the river continuum concept (RCC). The middle reaches based on the phytobenthos or phytoplankton communities and chl-a concentrations which were employed as proxies for primary production, were the most productive, while the upper reaches were the least primary productive. The evaluation of organic matter contributions to the SPM and detritus along the river–estuary continuum provided a baseline assessment of the nature and sources of potential food for consumers inhabiting different locations during different times of the year. Incorporating such spatio-temporal variations in SPM and detritus into food web studies will improve our understanding of the flow of carbon through aquatic systems.
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Lukas, Martynas. "Elektrinio variatoriaus panaudojimas dyzelinio variklio darbo optimizavimui." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2013. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2013~D_20130611_134356-26786.
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Darbe nagrinėjami elektros varikliais valdomi planetiniai reduktoriai - variatoriai. Atliktos mokslinių straipsnių analizės metu susipažinta su įvairių rūšių automobiliuose naudojamomis transmisijomis: pateikta jų klasifikacija, apžvelgtos dažniausiai naudojamos transporte pavarų dėžės. Pateikta tyrimo metodika, apžvelgti eksperimentinių tyrimų įrenginiai ir priemonės. Atlikti elektros varikliu valdomo planetinio reduktoriaus eksperimentai su suprojektuotu tyrimo stendu. Palygintos belaipsnės pavarų dėžės su parinktu dyzeliniu varikliu, bei pateiktos išvados ir rekomendacijos.This thesis analyzes the electric motor which controlled by planetary gearboxes - variator. Accomplished scientific articles during the analysis been familiarized with different kinds of transmissions which used in vehicles: submitted their classification, reviewed most commonly gearbox which used in transport. Submitted research methods, an overview of experimental research equipment and facilities. Performed experiments of electric motor controlled by planetary gear with designed study stand. Were was compared continuous variable transmission with a selected on diesel engine, submitted conclusions and recommendations.
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Shahdin, Amir. "Surveillance vibratoire de l'endommagement dû à l'impact sur poutres en matériaux composites stratifiés, sandwiches et matériaux enchevêtrés par variations des paramètres modaux." Toulouse, ISAE, 2009. http://www.theses.fr/2009ESAE0019.
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La Surveillance de la Santé des Structures (SSS) s'effectue par la mesure de réponses pertinentes sous sollicitations extérieurs. L'identification a pour but de détecter, de localiser et de quantifier ces défauts. La thèse porte sur les deux premiers niveaux de SSS, la détection et la localisation de dommage. Le but est d'étudier les effets d'impacts symétriques par variations des paramètres modaux en faisant un nombre important d'expériences. Une validation par recalage de modèles éléments finis est effectuée sur différents matériaux composites dédiés à l'aéronautique. Pour tous les spécimens (poutres), il a été observé que, avec l'accumulation de l'endommagement (impact), il y a une diminution de la fréquence propre (flexion) accompagnée par une augmentation du taux d'amortissement. Un aspect nouveau de cette thèse concerne la fabrication et les essais mécaniques (statique et dynamique) d'un matériau innovant (sandwich avec âme en fibre de carbones enchevêtrés) possédant des taux d'amortissements élevés ainsi qu'une meilleure résistance à l'impact. La modélisation par éléments finis (Samcef) est utilisée pour calculer la réponse dynamique de ces poutres. Ces modèles recalés permettent de donner un indicateur de taux de dégradation et peuvent servir d'outils diagnostic (et d'alarme) pour la surveillance de l'intégrité des structures. Une partie innovante de cette thèse concerne la localisation de l'endommagement et sa validation sur les poutres composites stratifiées par optimisation topologique (Nastran), en utilisant les paramètres modaux obtenus expérimentalement. Ainsi on estime avec succès les zones d'endommagement pour des défauts isolés.
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Akpossan, Johanne. "La consonne /R/ comme indice de la variation lectale : cas du français en contact avec le créole guadeloupéen." Thesis, Sorbonne Paris Cité, 2015. http://www.theses.fr/2015PA030010/document.
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Cette thèse a pour objectif de définir l’apport de la phonétique expérimentale dans l’identification d’une variété lectale, en prenant pour exemple les langues parlées en Guadeloupe. En Guadeloupe, deux langues cohabitent : le français et le créole. Mais, dans les faits, il y a une diversité de variétés de français d’une part, et de créole d’autre part. Chacune de ces variétés va de l’acrolecte au basilecte en passant par le mésolecte : il y a donc un continuum français et un continuum créole. La situation sociolinguistique de la Guadeloupe peut être ainsi représentée par un double continuum.Ces différentes variétés de français peuvent-elles se distinguer par des caractéristiques (1) acoustiques, (2) phonétiques, (3) phonologiques et (4) perceptives de la consonne /R/? La durée du contact avec le créole, a t-elle une influence sur la variété de français parlée par un locuteur ?Nos résultats montrent que plus la variété de français est basilectale, (1) plus la diffusion de l’énergie spectrale du /R/ est faible avec un taux de bruit réduit et une hauteur moyenne des fréquences basse ; (2) plus la variante fricatisée du /R/ est rare et plus la variante approximante est fréquente ; (3) plus le taux d’élision du /R/ en coda de syllabe augmente ainsi que le taux de réalisation de /R/ en tant que [w] en contexte labial; (4) plus la variété est perçue comme ayant un faible degré d’accent français. Généralement, plus la durée du contact entre le français et le créole est longue, plus cette variété est basilectale.Si les caractéristiques de la consonne /R/ permettent de discriminer la variété acrolectale de la variété basilectale (variétés extrêmes), il apparait plus difficile d’établir une liste d’indices (ou « lectomètres ») qui permettraient d’identifier les variétés se trouvant dans la zone intermédiaire : le mésolecte est doté d’une certaine imprévisibilitéThe goal of this thesis is to determine the contribution of experimental phonetics in the identification of a lectal variety, in taking for example languages spoken in Guadeloupe. In Guadeloupe, two languages coexist : French and Creole. But in fact, there is a diversity of varieties of French on the one hand, and of Creole on the other hand. Each of these varieties goes from acrolect to basilect through mesolect : so there are a French continuum and a Creole continuum. Thus, the sociolinguistic situation of Guadeloupe can be represented by a double continuum.These different varieties of French can they be distinguished by (1) acoustic, (2) phonetic, (3) phonological (4) and perceptual characteristics of /R/ consonant? Does the contact duration with Creole have an influence on the variety of French spoken by a speaker?Our results show that the more basilectal the variety of French is, (1) the lower spectral diffusion of /R/ energy is, with a reduced rate noise and a low frequency mean; (2) the more infrequent /R/ constrictive variants are and the more common /R/ approximant variants are ; (3) the greater rates of /R/ elision in coda of syllable and /R/ realization as [w] in labial context increase ;(4) and the more the variety is perceived as having a low degree of French accent. Usually, the longer duration of the contact between French and Creole is, the more basilectal the variety of French is.If characteristics of /R/ consonant can distinguish acrolect and basilect (extreme varieties), it’s not so easy to establish a list of indications (or « lectomètres ») in order to identify varieties in the intermediate zone: mesolect has a certain unpredictability
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Geromel, fischer Arthur. "Variational approach to dynamic fracture and applications to the fragmentation of metals and ceramics." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLX096/document.
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Le principal objectif de ce travail est l'étude de la fragmentation d'enveloppes métalliques. Cette thèse est divisée en quatre parties : la construction d'un modèle d'endommagement, l'implémentation numérique, la calibration des paramètres du modèle en utilisant des données expérimentales, et des travaux analytiques.Tout d'abord, nous avons considéré des modèles qui couplent les modèles d'endommagement classiques avec la plasticité et la dynamique. En utilisant l'énergie et l'action du système, nous avons obtenu toutes les équations qui décrivent le modèle dynamique et ductile : l'équation de la dynamique, le critère de plasticité et le critère d'endommagement. Nous avons ensuite détaillé l'implémentation numérique de ces modèles.Des résultats qualitatifs ont ensuite pu être obtenus, comme le nombre et la direction des fissures, ainsi que la convergence vers le modèle quasi-statique.Afin de mieux comprendre l'influence de chaque paramètre du modèle, nous avons étudié analytiquement le problème. A partir de l'observation de l'amplitude des perturbations, nous avons pu décrire comment obtenir une approximation analytique du nombre de fissures dans le cas d'un anneau en expansion.Cependant, pour être capable de simuler des problèmes réalistes, il est nécessaire de calibrer les paramètres du modèle. Nous nous sommes intéressés plus particulièrement au cas des matériaux fragiles. Les données expérimentales ont été obtenues par une série d'expériences réalisée par le CEA.Afin d'empêcher la localisation de la déformation plastique dans des bandes d'épaisseur nulle, d'autres formes de régularisation ont été étudiées, comme par exemple, l'utilisation des propriétés dissipatives du champ de température.Enfin, nous avons conclu ce travail en proposant des modèles de plasticité où l'énergie dépend aussi du gradient de la déformation plastique (modèles de plasticité à gradient)The main objective of this work was the study of the fragmentation of a metallic shell. This thesis is divided into four parts: construction of a damage model, numerical implementation, calibration of the model parameters using experimental data and analytical works.In this work, we considered a model that couples the standard gradient damage models with plasticity and dynamics. Using the energy and the action of the system, we could obtain all the equations necessary to describe the dynamic ductile model: the equations of dynamics, the plasticity criterion and the damage criterion. We then detail the numerical implementation of these models.Some qualitative behaviours are then obtained, such as the number and the direction of cracks, and the convergence to the quasi-static model.In order to better understand the influence of the parameters, we studied the problem analytically. By studying the amplitude of the perturbations, we describe how to obtain an analytic approximation for the number of cracks in a ring under expansion.In order to run realistic simulations, it is needed to calibrate the material parameters. We focus here on a simple case of brittle materials. The experimental data were obtained in a series of shockless spalling tests performed by the CEA.We also study other forms of regularization, now applied to the plastic strain, avoiding localization in zero-thickness bands.We considered using the dissipative properties of the temperature field to regularize the model. Finally, we conclude with plasticity models where we add a term depending on the gradient of the plastic strain (gradient plasticity models)
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Junuthula, Ruthwik Reddy. "Modeling, Evaluation and Analysis of Dynamic Networks for Social Network Analysis." University of Toledo / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1544819215833249.
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Abuhelou, Fayez. "Les variations spatiales et temporelles de l'occurrence et de la distribution de composés aromatiques polycycliques dans un système fluvial affecté par activités industrielles passées." Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0233/document.
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La contamination en composés aromatiques polycycliques (CAP) a été suivie entre 2014 et 2015 au cours de six campagnes d’échantillonnage sur 8 sites différents entre Auboué et Richemont. Cette section du cours d’eau correspond à la partie aval de la vallée de l’Orne profondément affectée par plus d’un siècle d’activités minières et sidérurgiques qui ont cessé entre 1968 et 2009. L’Orne a donc été le réceptacle de rejets industriels et urbains et a été profondément perturbée dans son hydrodynamisme avec la construction de plusieurs barrages. Dans ce contexte, l’occurrence des 16 hydrocarbures aromatiques polycycliques réglementaires (HAP), de 11 CAP oxygénés (O-CAP) et de 5 CAP azotés (N-CAP) et leur distribution dans les fractions dissoute et particulaire des eaux de l’Orne ont été étudiées en mettant en place des protocoles d’échantillonnage et d’analyse adaptés. Le premier objectif de ce travail a été de comparer les méthodes d’échantillonnage des matières en suspension par filtration et par centrifugation à flux continu sur le terrain. Des différences significatives ont pu être identifiées entre les deux techniques, la filtration amenant à des concentrations en CAP plus élevées du fait d’une plus grande abondance des CAP de bas poids moléculaire. Nous avons pu mettre en évidence le rôle de la fraction fine (< 5µm) et/ou colloïdale plus ou moins retenue par les filtres et qui, de part sa réactivité, piège des CAP. La comparaison des deux méthodes dans différentes situations hydrologiques nous montre que cette rétention n’est pas systématique mais plutôt corrélée à des situations de fort hydrodynamisme. Les deux méthodes d’échantillonnage des matières en suspension ne sont donc pas comparables mais complémentaires. Le suivi saisonnier et multi-sites des eaux de l’Orne montre que la concentration en CAP varie entre 1.6 et 223.7 ng L-1 dans la fraction dissoute et entre 1.5 et 105.5 µg g-1 dans la fraction particulaire avec des variations spatiales de ±35% et ±45% respectivement. Les variations de concentration des CAP dans la fraction dissoute sont importantes d’un site à l’autre lorsque le débit est faible (de 0.5 à 34 m3.s-1). Les concentrations en CAP sont faibles autour de 20 ng.L-1 et spatialement homogènes en périodes de haut débit (> 50 m3.s-1) du fait de la dilution. Les concentrations en CAP dans les matières en suspension varient entre 2.8 to 36.3 µg g-1, et montrent des concentrations stables quelles que soient les situations hydrologiques lorsqu’elles sont collectées par la centrifugeuse de terrain. La fraction dissoute est enrichie en HAP de bas poids moléculaire dans les périodes d’étiage et est marquée par l’occurrence des HAP à 5 et 6 cycles aromatiques au cours des épisodes de crue. Les CAP polaires sont au moins aussi abondants que les HAP dans la fraction dissoute et évoluent de la même façon que les HAP. La part des CAP polaires dans la fraction particulaire est significativement plus basse (de 10 à 20% de l’ensemble des CAP)The spatio-temporal variations of the concentration and distribution of dissolved and particulate polycyclic aromatic compounds (PACs), namely 16 polycyclic aromatic hydrocarbons (PAHs), 11 oxygenated PACs (O-PACs) and 5 nitrogen PACs (N-PACs), were studied in the Orne, a river impacted for more than one century by iron mining and steel-making industry. The first objective of this work was to compare the influence of two different methods of separation of suspended particulate matter (SPM), filtration (FT) and field continuous flow centrifuge (CFC). Results showed that in half of the sampling campaigns, PAC concentrations were 2 to 8 times higher for PAHs and 2 to 10 times higher for O-PAC when SPM were collected by filtration. These differences that were not observed systematically over the six sampling campaigns could be explained by the retention of colloidal matter on glass-fiber filters that appeared as a very reactive phase particularly enriched in low molecular PACs. The two methods were then considered as complementary methods to study SPM. The second objective of this work was to perform a long term monitoring of PAC concentrations and distributions in dissolved and particulate fractions. The results from the six sampling campaigns between May 2014 and September 2015 in eight different sites showed that the PAC concentrations ranged between 1.6 to 223.7 ng L-1 in the dissolved fraction (?PACTD), and between 1,55 to 105,5 µg g-1 in the total particulate fraction, with maximum spatial variation of ±35% and ±45% respectively. The dissolved PACs spatial variations were strongly influenced by the hydrological conditions and less spatial variation was observed during high flow events as the result of dilution and homogenization of pollutants. During low flow events, particulate PACSPM-CFC concentrations were more stable and equivalent in values and distribution to the corresponding PACSPM-FT samples. Overall it was in a range between 2.8 to 36.3 µg g-1. The dominance of dissolved low molecular weight PAHTD in the low flow events decreased during high flow events due to the appearance of penta- and hexa-cyclic PAHs. The dissolved polar PACs were as high as the PAHs contribution and also subjected to seasonal changes, the O-PACs ranged between 5.6 to 90.3 ng L-1 and N-PAHs from 1.0 to 42.5 ng L-1. The particulate polar PACs concentrations and contribution were significantly lower, the highest concentrations of 8,76 µg g-1 and 29,41 µg g-1 was observed during high flow event for O-PACs and during low flow event for N-PAH respectively
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Le, Duc Trung. "Modèle d'endommagement à gradient : approche par homogénéisation." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066662/document.
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L'objectif de cette thèse est de proposer une démarche de modélisation à partir de niveau microstructure pour obtenir un modèle d'endommagement à gradient. Elle se fonde, d'une part, sur la méthode d'homogénéisation pour construire un milieu effectif à partir de la microstructure donnée, et d'autre part, sur la formulation variationnelle, à l'échelle macroscopique, d'une loi d'évolution d'endommagement à partir du milieu homogénéisé. Nous construisons dans un premier temps une approche basée sur le développement asymptotique et de la méthode variationnelle pour homogénéiser un milieu élastique périodique. Afin de modéliser le phénomène de localisation d'endommagement , cette approche a été étendue à un milieu hétérogène quasi périodique. Par un exemple du milieu micro fissuré quasi périodique, nous obtenons une énergie élastique qui dépend non seulement du gradient de l'endommagement mais aussi du gradient de déformation. Dans la deuxième partie, nous construisons un modèle d'endommagement à gradient à partir de l'énergie élastique homogénéisé en se basant sur la principe de minimisation d'énergie. En ajoutant des hypothèse pour simplifier le modèle, nous pouvons construit explicitement des états localisés d'endommagement et de déformation. Enfin, un schéma de résolution numérique, basé sur un algorithme de minimisation alternée, a été proposé pour le cas d'un barre en traction. A partir des résultats numériques, les avantages et les inconvénients du modèle sont discutésThe aim of this work is to propose a general framework to obtain a gradient damage model from the micro-structural level. It is based, firstly, on the homogenization method to derive an effective medium from the microstructure, and secondly, on the variational formulation of a damage evolution law from the homogenized medium. We propose, as a first step, an approach based on asymptotic expansion and the variational method for homogenizing a periodic elastic medium. To model the localization of damage, this approach has been extended to a quasi-periodic heterogeneous medium. From an example of quasi periodically micro-cracked solid, we obtain an elastic energy that not only depends on the gradient of the damage but also the strain gradients. Based on the principle of energy minimization, we propose the construction of a gradient damage model from the elastic energy homogenized in the second part. By adding some hypothesis to simplify the model, we can construct localized damage and strain solutions in closed form. Finally, a numerical resolution scheme, which is based on an alternate minimization algorithm, is proposed for the one-dimensional traction bar test. From the numerical results, the advantages and disadvantages of the model are discussed
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Biazolli, Caroline Carnielli [UNESP]. "Posição de clíticos pronominais em duas variedades do português: inter-relações de estilo, gênero, modalidade e norma." Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/144643.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O propósito desta tese é avaliar como a questão de continua – estilístico e fala/escrita – e de gêneros textuais contribui para o entendimento de processos em variação. Para isso, investiga-se o fenômeno variável da posição de clíticos pronominais, observando-se como as variantes previstas – pré-verbal e pós-verbal, no caso de lexias verbais simples, e pré-complexo verbal, intra-complexo verbal, com ênclise ao primeiro verbo ou próclise ao segundo, e pós-complexo verbal – se manifestam em quatro gêneros textuais jornalísticos (entrevista na TV, noticiário de TV, carta do leitor e editorial), produzidos nos primeiros anos do século XXI e marcados por diferenças relacionadas às suas concepções discursivas, aos seus meios de produção e a outras características situacionais. Desenvolve-se um estudo descritivo-comparativo entre o português europeu (PE) e o português brasileiro (PB), fundamentado nos pressupostos teórico-metodológicos da Teoria da Variação e Mudança Linguísticas (WEINREICH; LABOV; HERZOG, 2006[1968]; LABOV, 1966, 1982, 1994, 2001a, 2003, 2008[1972]) e em conceitos relativos a estilo (LABOV, 1966, 2008[1972]; BELL, 1984, 2001), gêneros textuais (BAKHTIN, 1992[1979]; MARCUSCHI, 2005, 2008, 2010; BIBER; CONRAD, 2009), modalidades de uso da língua (CHAFE, 1982; 1985; BIBER, 1988; MARCUSCHI, 2008, 2010) e normas linguísticas (COSERIU, 1979[1952]; BAGNO, 2003, 2011, 2012; FARACO, 2008, 2011, 2012). Antes de se chegar às análises qualitativas que versam sobre influências externas no fenômeno em foco, detalham-se os possíveis condicionamentos linguísticos favorecedores das formas alternantes de colocação pronominal, valendo-se do tratamento estatístico oferecido pelo programa Goldvarb X (SANKOFF et al., 2005). Os resultados sinalizam que, no PE, a posição dos pronomes clíticos está intimamente relacionada a fatores estruturais, enquanto no PB tal objeto parece também ser sensível à ação de elementos não linguísticos. Desse modo, com base nos registros da variedade brasileira do português, mostra-se a coerência de se unir à observação de motivações linguísticas uma investigação sobre o maior número possível de aspectos vinculados às situações comunicativas. Confirma-se, portanto, que o continuum estilístico, correlacionado aos próprios gêneros e ao continuum fala/escrita, funciona como caminho de difusão de fenômenos em variação. Por último, cumpre destacar que o presente estudo colabora com a profícua discussão, vigente na literatura linguística, acerca da colocação pronominal e, de modo mais amplo, além de auxiliar no aprofundamento teórico relacionado às variações diafásica, diamésica e sociocultural, coopera com a pesquisa sociolinguística desenvolvida em Portugal e no Brasil, acrescentando mais resultados à descrição dessas variedades e da língua portuguesa como um todo.
The aim of this work is to evaluate how the question of continua – stylistic and speech/writing – and how textual genres contribute to the understanding of the variation process. It was investigated the variable phenomenon of the placement of pronominal clitics, observing how the predicted variables – pre-verbal and post-verbal, in the case of simple verbal lexical items, and pre-verbal complex, intra-verbal complex, with enclisis in the first verb or proclisis in the second, and post-verbal complex – are manifested in four journalistic textual genres (TV interview, TV news, readers’ letter and editorial), produced in the first years of the 21st century and marked by differences related to their discursive conceptions, to their means of production and other situational characteristics. It was developed a descriptive-comparative study between the European Portuguese (EP) and the Brazilian Portuguese (BP), founded in the theoretical-methodological assumptions of the Theory of Variation and Linguistic Change (WEINREICH; LABOV; HERZOG, 2006[1968]; LABOV, 1966, 1982, 1994, 2001a, 2003, 2008[1972]) and in concepts related to style (LABOV, 1966, 2008[1972]; BELL, 1984, 2001), textual genres (BAKHTIN, 1992[1979]; MARCUSCHI, 2005, 2008, 2010; BIBER; CONRAD, 2009), modalities of language use (CHAFE, 1982; 1985; BIBER, 1988; MARCUSCHI, 2008, 2010) and linguistic norms (COSERIU, 1979[1952]; BAGNO, 2003, 2011, 2012; FARACO, 2008, 2011, 2012). Before the qualitative analysis about the external influences in this phenomenon, it was detailed the possible linguistic conditioning which favour the alternating forms of pronominal collocation using the statistic treatment offered by Goldvarb X (SANKOFF et al., 2005). The results show that in EP, the placement of pronominal clitics is intimately related to structural factors, while in BP, it also seems to be sensitive to the action of non-linguistic elements. In this way, according to the data of Brazilian Portuguese, it is observed the consistency to join the observation of linguistic motivations and the investigation about the highest number of aspects bounded to communicative situations. It is validated, thus, that the stylistic continuum, correlated to the genres and to the continuum speech/writing, works as a way of diffusion of variable phenomena. At last, it is required to highlight that this study collaborates with the fruitful discussion – current in the linguistic literature – about the pronominal collocation and, in a broader way, it also auxiliaries in the further theoretical development related to the diaphasic, diamesic and sociocultural variations, cooperates with the sociolinguistics research developed in Portugal and in Brazil, adding more results to the description of these varieties and to the Portuguese language as a whole.
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Signorini, Caroline de Arruda [UNESP]. "Condições de otimalidade em cálculo das variações no contexto não-suave." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/149892.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Nosso principal propósito neste trabalho é o estudo de condições necessárias e suficientes de otimalidade para problemas de Cálculo das Variações no contexto não-suave. Este estudo partirá da formulação básica suave, passando por problemas com restrições Lagrangianas, até o caso em que consideramos Lagrangianas não-suaves e soluções absolutamente contínuas. Neste caminho, abordaremos um importante avanço na teoria de Cálculo das Variações: os resultados de existência e regularidade de soluções. Além das condições necessárias, analisaremos as condições suficientes através de um conceito de convexidade generalizada, o qual denominamos E-pseudoinvexidade.
Our main purpose in this work is the study of necessary and sufficient optimality conditions for Calculus of Variations problems in the nonsmooth context. This study will comprehend the smooth basic formulation, constrained problems (with Lagrangian restrictions), non-smooth Lagrangians and absolutely continuous solutions. Moreover, we will approach an important advance in Calculus of Variations theory: the existence and regularity of solutions. In addition to necessary conditions, we will analyze sufficient conditions through a generalized convexity concept, which we called E-pseudoinvexity.
FAPESP: 2014/24271-6
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CARDOSO, Cristiane Alves de Lima. "Concord?ncia verbal de 1? PP no 6? ano: do diagn?stico ? interven??o pedag?gica." Universidade Federal Rural do Rio de Janeiro, 2015. https://tede.ufrrj.br/jspui/handle/jspui/1296.
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CAPES
This paper aims to present a pedagogical intervention proposal for the study of variable rule verbal agreement of the 1st person plural in the 6th grade of Elementary School, based on the diagnosis done in 2014, in a public school of Duque de Caxias. Three aspects were taken into consideration in the composition of this diagnosis: (1) a study based on the Labovian Variationist Sociolinguistic (WEINREICH; LABOV; HERZOG, 1968) concerning the verbal agreement of the 1st person plural produced by 6th graders, (2) a survey carried out through a questionnaire of the beliefs and attitudes of Portuguese teachers of the school as to the use and study of this linguistic phenomenon and (3) an analysis of the pedagogical approach proposed by the coursebook chosen by the school. The results of the sociolinguistic study showed a considerable variation of the 1st person plural agreement in the student?s speaking and writing. The answers to the beliefs and attitudes test indicated that the pedagogical action around this variable phenomenon has concentrated on correction and reading practices. The analyzed coursebook does not consider the verbal agreement phenomenon explicitly, but presents an extensive grammatical study of verbs from which it can be concluded that it is up to the school teaching the explicit realization of bending 1st person plural. In developing the proposal itself, the theoretical methodological foundation was based on association between the Model of Continuous (BORTONI-RICARDO, 2004), with an emphasis on the continuous stylistic monitoring and didactic-pedagogic approach of the collaborative apprenticeship (BEHRENS, 2013).
Este trabalho tem como objetivo apresentar uma proposta de interven??o pedag?gica para o estudo da regra vari?vel de concord?ncia verbal de 1? pessoa do plural no 6? ano do Ensino Fundamental, elaborada a partir do diagn?stico realizado no ano de 2014, em uma escola da Rede Municipal de Duque de Caxias. Tr?s aspectos foram considerados na composi??o desse diagn?stico: (1) um estudo com base na Sociolingu?stica Variacionista Laboviana (WEINREICH; LABOV; HERZOG, 1968) sobre o estatuto da concord?ncia verbal de 1? pessoa do plural produzida por alunos do 6? ano, (2) uma sondagem, por meio de um question?rio, das cren?as e atitudes dos professores de L?ngua Portuguesa da escola quanto ao uso e ao estudo desse fen?meno lingu?stico e (3) uma an?lise da abordagem pedag?gica proposta pelo livro did?tico adotado na unidade escolar. Os resultados obtidos no estudo sociolingu?stico revelaram uma acentuada varia??o da concord?ncia de 1? pessoa do plural na fala e na escrita dos estudantes. As respostas ao teste de atitudes e cren?as indicaram que a a??o pedag?gica em torno desse fen?meno vari?vel tem se concentrado em pr?ticas de corre??o e de leitura. O livro did?tico analisado n?o contempla explicitamente o fen?meno da concord?ncia verbal, mas apresenta um extenso estudo gramatical sobre verbos a partir do qual se conclui que ? escola cabe o ensino da realiza??o expl?cita da flex?o de 1? pessoa do plural. Para a elabora??o da proposta propriamente dita, procedeu-se, como fundamenta??o te?rico-metodol?gica, ? associa??o entre o Modelo dos Cont?nuos (BORTONI-RICARDO, 2004), com ?nfase no cont?nuo de monitoramento estil?stico, e a abordagem did?tico-pedag?gica de aprendizagem colaborativa (BEHRENS, 2013).