Dissertations / Theses on the topic 'Large'
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Horsley, David James. "Large-diameter large-ratio hot tap tees." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0009/MQ31321.pdf.
Full textLaflamme, Simon Ph D. Massachusetts Institute of Technology. "Control of large-scale structures with large uncertainties." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/66852.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (p. 279-300).
Performance-based design is a design approach that satisfies motion constraints as its primary goal, and then verifies for strength. The approach is traditionally executed by appropriately sizing stiffnesses, but recently, passive energy dissipation systems have gained popularity. Semi-active and active energy dissipation systems have been shown to outperform purely passive systems, but they are not yet widely accepted in the construction and structural engineering fields. Several factors are impeding the application of semi-active and active damping systems, such as large modeling uncertainties that are inherent to large-scale structures, limited state measurements, lack of mechanically reliable control devices, large power requirements, and the need for robust controllers. In order to enhance acceptability of feedback control systems to civil structures, an integrated control strategy designed for large-scale structures with large parametric uncertainties is proposed. The control strategy comprises a novel controller, as well as a new semi-active mechanical damping device. Specifically, the controller is an adaptive black-box representation that creates and optimizes control laws sequentially during an excitation, with no prior training. The novel feature is its online organization of the input space. The representation only requires limited observations for constructing an efficient representation, which allows control of unknown systems with limited state measurements. The semi-active mechanical device consists of a friction device inspired by a vehicle drum brakes, with a viscous and a stiffness element installed in parallel. Its unique characteristic is its theoretical damping force reaching the order of 100 kN, using a friction mechanism powered with a single 12-volts battery. It is conceived using mechanically reliable technologies, which is a solution to large power requirement and mechanical robustness. The integrated control system is simulated on an existing structure located in Boston, MA, as a replacement to the existing viscous damping system. Simulation results show that the integrated control system can mitigate wind vibrations as well as the current damping strategy, utilizing only one third of devices. In addition, the system created effective control rules for several types of earthquake excitations with no prior training, performing similarly to an optimal controller using full parametric and state knowledge.
by Simon Laflamme.
Ph.D.
Pechenik, Oliver. "Large Cardinals." Oberlin College Honors Theses / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=oberlin1279129907.
Full textBroomfield, Susannah Elizabeth. "Large deflection, nonlinear loads analysis, with application to large winglets." Thesis, University of Bristol, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492476.
Full textGoldschmidt, Christina Anna. "Large random hypergraphs." Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.615618.
Full textCuervo, Maria Cristina. "Datives at large." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/7991.
Full textIncludes bibliographical references (p. 206-211).
This dissertation is a study of the syntactic and semantic properties of dative arguments. The main source of data is Spanish, where dative arguments can appear with all types of verbs, and can have a wide range of meanings: goal, possessor, source, experiencer, affected object, causee, location, benefactive, malefactive, ethical dative. The challenge for a theory of dative arguments, which form a natural class morphologically, is to explain both what they have in common and how they differ syntactically and semantically. I argue that dative arguments have structural meanings, i.e., the meaning of a dative DP can be derived directly from the position in which it is licensed. To be able to predict the possible meanings of dative arguments, it is crucial to take into account the details of the syntactic configuration, which include the properties of the head that licenses the dative DP and of the functional heads that construct the event structure. Dative arguments are not direct arguments of the verb; they are, like subjects, licensed syntactically and semantically by a specialized head. This argument introducing head, the Applicative, licenses the dative DP as its specifier and relates this DP to the structure it takes as a complement. The range of possible meanings of a dative DP is predicted from the range of possible complements an applicative head can take (i.e. a DP or a vP), and from the range of heads that the applicative phrase can be a complement of. Applicative heads are also sensitive to the type of event expressed by the vP (e.g., dynamic or stative, activity or causative). The theory provides a set of positions into which an applicative head can merge and license an argument DP, as well as the set of interpretations the argument can get in each position.
(cont.) The set of positions is universal, but languages can differ with respect to the positions into which an applicative head is allowed to merge. These predictions generalize to applied arguments in languages in which they are not marked by dative case (e.g., English and Bantu languages).
by María Cristina Cuervo.
Ph.D.
Tew, David Peter. "Large amplitude vibration." Thesis, University of Cambridge, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619693.
Full textWu, Junyang. "Large current rectifiers." Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611994.
Full textБашлак, Ірина Анатоліївна, Ирина Анатольевна Башлак, Iryna Anatoliivna Bashlak, and T. Nikolaenko. "Large hadron collider." Thesis, Вид-во СумДУ, 2009. http://essuir.sumdu.edu.ua/handle/123456789/16770.
Full textДядечко, Алла Миколаївна, Алла Николаевна Дядечко, Alla Mykolaivna Diadechko, and D. A. Dedik. "Large hadron collider." Thesis, Видавництво СумДУ, 2010. http://essuir.sumdu.edu.ua/handle/123456789/18312.
Full textSonnenwald, Diane H., Paul Soloman, Noriko Hara, Reto Bolliger, and Tom Cox. "Collaboration in the large: Using video conferencing to facilitate large group interaction." Idea Publishing Co, 2002. http://hdl.handle.net/10150/106015.
Full textO'Mahony, Kevin. "Large scale plasmid production /." [S.l.] : [s.n.], 2005. http://library.epfl.ch/theses/?nr=3320.
Full textMatt, Urs von. "Large constrained quadratic problems /." Zürich, 1993. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=9979.
Full textBatlle, Subirós Elisabet. "Large-Scale Surface registration." Doctoral thesis, Universitat de Girona, 2008. http://hdl.handle.net/10803/7606.
Full textThe main contribution of this thesis is the proposal of a new 3D multiview registration strategy. The proposed approach detects revisited regions obtaining cycles of views that are used to reduce the inaccuracies that may exist in the final model due to error propagation. The method takes advantage of both global and local information of the registration process, using graph theory techniques in order correlate multiple views and minimize the propagated error by registering the views in an optimal way. The proposed method has been tested using both synthetic and real data, in order to show and study its behavior and demonstrate its reliability.
La primera part d'aquest treball presenta una anàlisi acurada de les tècniques de registre 3D es rellevants, incloent tècniques d'estimació de la posició inicial, registre pairwise i registre entre múltiples vistes. S'ha proposat una nova classificació de les tècniques, depenent de les seves aplicacions i de l'estratègia utilitzada.
La contribució mes important d'aquesta tesi és la proposta d'un nou mètode de registre 3D utilitzant múltiples vistes. El mètode proposat detecta regions ja visitades prèviament, obtenint cicles de vistes que s'utilitzen per tal de reduir els desalineaments en el model final deguts principalment a la propagació de l'error durant el procés de registre. Aquest mètode utilitza tant informació global com local, correlacionant les vistes mitjançant tècniques de grafs que permeten minimitzar l'error propagat i registrar les vistes de forma òptima. El mètode proposat ha estat provat utilitzant dades sintètiques i reals, per tal de mostrar i analitzar el seu comportament i demostrar la seva eficàcia.
Das, Sarma Atish. "Algorithms for large graphs." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34709.
Full textBorsa, Christopher. "Large Area Graphene Synthesis." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-93758.
Full textBanon, Navarro Alejandro. "Gyrokinetic large Eddy simulations." Doctoral thesis, Universite Libre de Bruxelles, 2012. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209592.
Full textDu point de vue théorique, la turbulence plasma est décrite par les équations gyrocinétiques, un ensemble d équations aux dérivées partielles non linéaires couplées. Par suite des très différentes échelles spatiales mises en jeu dans des conditions expérimentales réelles, une simulation numérique directe et complète (DNS) de la turbulence gyrocinétique est totalement hors de portée des plus puissants calculateurs actuels, de sorte que démontrer la faisabilité d’une alternative permettant de réduire l’effort numérique est primordiale. En particulier, les simulations de grandes échelles (”Large-Eddy Simulations” - LES) constituent un candidat pertinent pour permettre une telle r éduction. Les techniques LES ont initialement été développées pour les simulations de fluides turbulents à haut nombre de Reynolds. Dans ces simulations, les plus grandes échelles sont explicitement simulées numériquement, alors que l’influence des plus petites est prise en compte via un modèle implémenté dans le code.
Cette thèse présente les premiers développements de techniques LES dans le cadre des équations gyrocinétiques (GyroLES). La modélisation des plus petites échelles est basée sur des bilans d’énergie libre. En effet, l’energie libre joue un rôle important dans la théorie gyrocinétique car elle en est un invariant non lin éaire bien connu. Il est démontré que sa dynamique partage de nombreuses propriétés avec le transfert d’energie dans la turbulence fluide. En particulier, il est montré l’existence d’une cascade d énergie libre, fortement locale et dirigée des grandes échelles vers les petites, dans le plan perpendiculaire â celui du champ magnétique ambiant.
La technique GyroLES est aujourd’hui implantée dans le code GENE et a été testée avec succès pour les instabilités de gradient de température ionique (ITG), connues pour jouer un rôle crucial dans la micro-turbulence gyrocinétique. A l’aide des GyroLES, le spectre du flux de chaleur obtenu dans des simulations à très hautes résolutions est correctement reproduit, et ce avec un gain d’un facteur 20 en termes de coût numérique. Pour ces raisons, les simulations gyrocinétiques GyroLES sont potentiellement un excellent candidat pour réduire l’effort numérique des codes gyrocinétiques actuels.
/ Anomalous transport due to plasma micro-turbulence is known to play an important role in confinement properties of magnetically confined fusion plasma devices such as ITER. Indeed, plasma turbulence is strongly connected to the energy confinement time, a key issue in thermonuclear fusion research. Plasma turbulence is described by the gyrokinetic equations, a set of nonlinear partial differential equations. Due to the various scales characterizing the turbulent fluctuations in realistic experimental conditions, Direct Numerical Simulations (DNS) of gyrokinetic turbulence remain close to the computational limit of current supercomputers, so that any alternative is welcome to decrease the numerical effort. In particular, Large-Eddy Simulations (LES) are a good candidate for such a decrease. LES techniques have been devised for simulating turbulent fluids at high Reynolds number. In these simulations, the large scales are computed explicitly while the influence of the smallest scales is modeled.
In this thesis, we present for the first time the development of the LES for gyrokinetics (GyroLES). The modeling of the smallest scales is based on free energy diagnostics. Indeed, free energy plays an important role in gyrokinetic theory, since it is known to be a nonlinear invariant. It is shown that its dynamics share many properties with the energy transfer in fluid turbulence. In particular, one finds a (strongly) local, forward (from large to small scales) cascade of free energy in the plane perpendicular to the background magnetic field.
The GyroLES technique is implemented in the gyrokinetic code Gene and successfully tested for the ion temperature gradient instability (ITG), since ITG is suspected to play a crucial role in gyrokinetic micro-turbulence. Employing GyroLES, the heat flux spectra obtained from highly resolved direct numerical simulations are recovered. It is shown that the gain of GyroLES runs is 20 in terms of computational time. For this reason, Gyrokinetic Large Eddy Simulations can be considered a serious candidate to reduce the numerical cost of gyrokinetic simulations.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Woynicz, Richard A. "Large data network survivability." Master's thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-01202010-020136/.
Full textAkkerman, Hylke Broer. "Large-area molecular junctions." [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 2008. http://irs.ub.rug.nl/ppn/.
Full textHoover, Douglas Allan. "Supersymmetric large extra dimensions." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32520.
Full textCette thèse examine la viabilité d'une approche récente, dite des Dimensions Supplémentaires Larges Supersymétriques (Supersymmetric Large Extra Dimensions, or SLED), qui propose une solution au problème de la constante cosmologique et à celui de la hiérarchie. Un aspect central de cette approche est l'existence de deux dimensions supplémentaires de grande taille r_c ~ 10 micromètres, et la faible valeur de l'échelle de gravité, M_* ~ 10 TeV. Afin d'éviter un conflit immédiat avec l'expérience, tous les champs du Modèle Standard sont supposés être confinés dans les quatre dimensions observées (i.e. sur une brane). Une implémentation de cette idée de SLED est realisée par le biais de la supergravité 6D de Nishino et Sezgin (NS), dont on sait qu'elle a des compactifications 4D-plates. Un certain nombre de questions, laissées ouvertes lorsque cette thèse à débutée, sont à présent partiellement ou complètement résolues. En particulier, nous étendons les solutions connues de la supergravité NS; elle incluent à present: compactifications déformées ayant la symétrie de Sitter ou anti-de Sitter 4D, solutions statiques avec invariance de Lorentz 4D brisée, et solutions d'échelle ("scaling'') dépendentes du temps. La relation entre les propriétés des branes et la forme asymptotique des champs de bulk lorsqu'ils approchent la brane est mise en lumière et expliquée. La stabilité marginale des solutions 4D-plate est démontrée pour une large classe de conditions de bord. Etant donné que les solutions déformées de la supergravité NS que l'on considère sont singulières à l'emplacement de la brane, une procédure explicite de rég
Webster, Ali Matthew. "Quantifying large-scale structure." Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624308.
Full textXu, Changliang. "Large deviation for martingale." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.547460.
Full textTaylor, Amelia May. "Substructures in large graphs." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7241/.
Full textSchmid, Patrick R. (Patrick Raphael). "Large scale disease prediction." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/43068.
Full textIncludes bibliographical references (leaves 69-73).
The objective of this thesis is to present the foundation of an automated large-scale disease prediction system. Unlike previous work that has typically focused on a small self-contained dataset, we explore the possibility of combining a large amount of heterogeneous data to perform gene selection and phenotype classification. First, a subset of publicly available microarray datasets was downloaded from the NCBI Gene Expression Omnibus (GEO) [18, 5]. This data was then automatically tagged with Unified Medical Language System (UMLS) concepts [7]. Using the UMLS tags, datasets related to several phenotypes were obtained and gene selection was performed on the expression values of this tagged microarray data. Using the tagged datasets and the list of genes selected in the previous step, classifiers that can predict whether or not a new sample is also associated with a given UMLS concept based solely on the expression data were created. The results from this work show that it is possible to combine a large heterogeneous set of microarray datasets for both gene selection and phenotype classification, and thus lays the foundation for the possibility of automatic classification of disease types based on gene expression data in a clinical setting.
by Patrick R. Schmid.
S.M.
Pontzen, Andrew Peter. "Cosmology : small and large." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608426.
Full textFurman, Yoel Avraham. "Forecasting with large datasets." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:69f2833b-cc53-457a-8426-37c06df85bc2.
Full textRío, Pareja José Manuel. "Ornamentum : for large orchestra /." May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
Full textVorapanya, Anek. "Large-scale distributed services." [Florida] : State University System of Florida, 2000. http://etd.fcla.edu/etd/uf/2000/ana6855/dissertation.pdf.
Full textTitle from first page of PDF file. Document formatted into pages; contains xi, 112 p.; also contains graphics. Vita. Includes bibliographical references (p. 108-111).
Hellsten, Alex. "Diamonds on large cardinals." Helsinki : University of Helsinki, 2003. http://ethesis.helsinki.fi/julkaisut/mat/matem/vk/hellsten/.
Full textKermarrec, Anne-Marie. "Diffusion fiable large-échelle." [S.l.] : [s.n.], 2002. http://www.irisa.fr/centredoc/publis/HDR/2002/irisapublication.2005-08-03.2412138638.
Full textMazumdar, Suvodeep. "Visualising large semantic datasets." Thesis, University of Sheffield, 2013. http://etheses.whiterose.ac.uk/5932/.
Full textHill, Simon John. "Large amplitude fish swimming." Thesis, University of Leeds, 1998. http://etheses.whiterose.ac.uk/12760/.
Full textWAN, DER-SHEN. "OPTICS FOR LARGE TELESCOPE." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184226.
Full textLe, Tien Nam. "Patterns in Large Graphs." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEN079/document.
Full textA graph is a set of nodes, together links connecting pairs of nodes. With the accumulating amount of data collected, there is a growing interest in understanding the structures and behavior of very large graphs. Nevertheless, the rapid increasing in size of large graphs makes studying the entire graphs becomes less and less efficient. Thus, there is a compelling demand for more effective methods to study large graphs without requiring the knowledge of the graphs in whole. One promising method to understand the behavior of large graphs is via exploiting specific properties of local structures, such as the size of clusters or the presence locally of some specific pattern, i.e. a given (usually small) graph. A classical example from Graph Theory (proven cases of the Erdos-Hajnal conjecture) is that if a large graph does not contain some specific pattern, then it must have a set of nodes pairwise linked or not linked of size exponentially larger than expected. This thesis will address some aspects of two fundamental questions in Graph Theory about the presence, abundantly or scarcely, of a given pattern in some large graph: - Can the large graph be partitioned into copies of the pattern? - Does the large graph contain any copy of the pattern?We will discuss some of the most well-known conjectures in Graph Theory on this topic: the Tutte's flow conjectures on flows in graphs and the Erdos-Hajnal conjecture mentioned above, and present proofs for several related conjectures -- including the Barát-Thomassen conjecture, a conjecture of Haggkvist and Krissell, a special case of Jaeger-Linial-Payan-Tarsi's conjecture, a conjecture of Berger et al, and another one by Albouker et al
Clough, Eric C. "Large-displacement Lightweight Armor." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1122.
Full textMoberg, Désirée. "Transmission alternatives for grid connection of large offshore wind farms at large distance." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-65804.
Full textMed den stora potentialen hos världens hav, börjar havsbaserad vindkraft bli en betydande energikälla. Den ökande storleken på vindkraftsturbinerna tillsammans med de ökade avstånden mellan vindkraftsparkerna och land, gör att transmissionslösningen blir en mer betydelsefull komponent. Flera olika parametrar kan vara avgörande för transmissionslösningens lönsamhet, som investeringskostnad och effektförluster, men också saker som drift & underhåll och projektets ledtid. Studien är baserad på en planerad vindkraftspark med en märkeffekt på 1 200 MW och på ett avstånd på 125 km till anslutningspunkten. Fyra modeller av transmissionssnätet har gjorts, där tekniken har bestått av HVAC, HVDC samt en blandning av dessa. Simuleringarna har gjort i EeFarm II, ett program baserat på Matlab och Simulink. De fyra modellerna har jämförts tekniskt, med för- och nackdelar poängterade, och även ekonomiskt med hjälp av LCOE, NPV och IRR. Kostnader, effektförluster och tillgängligheten för vindkraftsturbinerna och internnätet i vindkraftsparken är inte inkluderade i studien. Resultaten av simuleringarna visar på att HVAC-lösningen är den mest lönsamma, med lägst Levelized Cost of Energy och högst Net Price Value och Internal Rate of Return. Värdena för dessa är 25,11 €/MWh, 387,60 M€ respektive 15,32 %. En HVDC-lösning med enbart en DC-plattform och likriktarstation för hela märkeffekten, har en LCOE inte långt ifrån HVAC-lösningen, men med en lite större skillnad i NPV och IRR (25,71 €/MWh, 300,76 M€ respektive 14,84 %). För att analysera påverkan av olika parametrar på de ekonomiska mätvärdena, har en osäkerhetsanalys gjort. Den största påverkan på resultatet syntes av förändringar av investeringskostnader och ledtider. Ovanstående resultat tyder på, med transmissionslösningar enligt modellerna i detta arbete, att brytpunkten där en HVDC-lösning är mer lönsam än en HVAC-lösning inte än är passerad vid ett avstånd på 125 km till anslutningspunkten. Med en fortfarande väldigt ung teknik för HVDC, kan den ständigt utvecklande tekniken i framtiden betyda kortare ledtider och en lägre investeringskostnad för en HVDC-lösning och möjligheten att vara en mer lönsam lösning. Komplikationer med en HVAC-lösning pga den extra landkabeln, som större landanvändning och med kabeltillverkningen som en flaskhals, kan ändå göra en HVDC-lösning mer praktisk.
Jacobson, A. P. "Large carnivores under threat : investigating human impacts on large carnivores in East Africa." Thesis, University College London (University of London), 2017. http://discovery.ucl.ac.uk/1559725/.
Full textJerhov, Carolina. "IN LARGE SCALE : the art of knitting a small shell in large scale." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-26582.
Full textMaged, Shireen. "The pedagogy of large classes : challenging the "large class equals gutter education" myth." Master's thesis, University of Cape Town, 1997. http://hdl.handle.net/11427/16133.
Full textThe study takes the work of three teachers to examine whether the popular belief of "small is better" is substantiated in the practice of these teachers. The study observes and analyses the classroom instruction of each of these teachers in a small class as well as in a large class. The observation is done with the use of an observation schedule, and the analysis of data is done within a Vygotskian framework. The study shows that the pedagogy and the teaching style of the three teachers does not change when they teach differently sized classes. In other words, their classroom practice is the same for both the small and large classes. The study further shows that the pedagogy of the teacher determines the effectiveness or quality of instruction, and that class size does not impact, either positively (in the case of the small class) or negatively (in the case of a large class) on the effectiveness or quality of instruction.
Chu, Wen-Hwa Martin. "Microfabricated tweezers with a large gripping force and a large range of motion." Case Western Reserve University School of Graduate Studies / OhioLINK, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=case1057869514.
Full textHipp, Guy L. "A strategy for team building with a large staff in a large church." Theological Research Exchange Network (TREN), 1993. http://www.tren.com.
Full textFeng, Shui 1962 Carleton University Dissertation Mathematics. "Large deviations of particle systems." Ottawa.:, 1992.
Find full textColomés, Gené Oriol. "Large scale finite element solvers for the large eddy simulation of incompressible turbulent flows." Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/392718.
Full textEn aquesta tesi s'han desenvolupat diferents algoritmes per la simulació a gran escala de fluxos turbulents incompressibles mitjançant el mètode dels Elements Finits. En primer lloc s'ha avaluat el comportament dels mètodes de multiescala variacional (VMS) basats en el residu, per la simulació de grans vòrtexs (LES) de fluxos turbulents. S'han considerat diferents models VMS tenint en compte diferents aproximacions de les subescales, que inclouen tant subescales estàtiques o dinàmiques, una definicó lineal o nolineal, i diferents seleccions de l'espai de les subescales. S'ha demostrat que els mètodes VMS pensats com a models LES poden ser una alternativa als models basats en la física del problema. Aquest tipus de mètode normalment es combina amb l'ús de parelles de velocitat i pressió amb igual ordre d'interpolació. En aquest treball, també s'ha considerat un enfocament diferent, basat en l'ús d'elements inf-sup estables conjuntament amb estabilització del terme convectiu. Amb aquest objectiu, s'ha definit un mètode d'estabilització amb projecció simètrica del terme convectiu mitjançant una descomposició ortogonal de les subescales. En aquesta tesi també s'ha valorat la precisió i eficiència d'aquest mètode comparat amb mètodes basats en el residu fent servir interpolacions amb igual ordre per velocitats i pressions. A més, s'ha proposat un esquema d'integració en temps basat en els mètodes de Runge-Kutta que té dues propietats destacables. En primer lloc, el càlcul de la velocitat i la pressió es segrega al nivell de la integració temporal, sense la necessitat d'introduir tècniques de fraccionament del pas de temps. En segon lloc, els esquemes segregats de Runge-Kutta proposats, mantenen el mateix ordre de precisió tant per les velocitats com per les pressions. Precisament, els mètodes d'estabilització amb projecció simètrica són adequats per ser integrats en temps mitjançant esquemes segregats de Runge-Kutta. Aquesta combinació, juntament amb l'ús de tècniques de precondicionament en blocs, dóna lloc a problemes tipus elasticitat i Laplacià que poden ser òptimament precondicionats fent servir els anomenats \textit{balancing domain decomposition by constraints preconditioners}. La escalabilitat dèbil d'aquesta formulació s'ha demostrat en aquest document. Adicionalment, també s'ha contemplat la imposició de forma dèbil de les condicions de contorn de Dirichlet en problemes de fluxos turbulents delimitats per parets. En aquesta tesi principalment s'han considerat quatre problemes ben coneguts per fer els experiments numèrics: el decaïment de turbulència isotròpica i homogènia, el problema del vòrtex de Taylor-Green, el flux turbulent en un canal i el flux turbulent al voltant d'una ala.
Wang, Dun. "Determination of Rupture Propagation for Large Earthquakes from Back-Projection Analyses Using Large Arrays." 京都大学 (Kyoto University), 2013. http://hdl.handle.net/2433/175126.
Full textZhang, Xu. "Large comportement au temps large de l'équation de Prandtl et des systèmes de magnétohydrodynamique." Rouen, 2016. http://www.theses.fr/2016ROUES015.
Full textThis thesis is made up of two parts. One is about the long time wellposedness of Prandtl equations with monotonicity assumption. The other one is the study of global solutions for inhomogeneous Magnetohydrodynamics system with bounded positive density. Recently, under the monotonic assumption, by using the energy method, Alexandre-Wang-Xu-Yang and Masmoudi-Wong have obtained the local in time existence of smooth solution in Sobolev space for Prandtl boundary layer equation, but the life span of their solution are very small. On the meantime, Xin-Zhang proved the global-in-time weak solution by Crocco transformation under monotonicity and favorable pressure assumption. The long time behavior of the Prandtl equations is important to make progress towards the inviscid limit of the Navier-Stokes equations. With this motivation, in the first part of this thesis, we study the long time well-posedness for the nonlinear Prandtl boundary layer equation on the half plane. We consider a class of the initial data as perturbations around a monotonic shear profile and we prove the existence, uniqueness and stability of solutions in weighted Sobolev space, whose life span can be arbitrarily long while the initial perturbations are small enough. We use the energy method to prove the existence of solutions by a parabolic regularizing approximation. The nonlinear cancellation properties of Prandtl equations under the monotonic assumption are the main ingredients to establish a new energy estimate. The second part of this thesis is about global well-posedness of inhomogeneous magnetohydrodynamics(MHD) system. Recently, Danchin-Mucha have obtained well posedness of inhomogeneous Navier-Stokes equation while the density could be discontinuous by using Lagrangian transformation, or the material derivative. We will prove the global well-posedness of inhomogeneous MHD system while the density just has a positive lower bound and the initial magnetic field contains large oscillations. We first get the à priori estimate in Euler coordinate and then prove the local-in-time well-posedness of inhomogeneous MHD system in Lagrangian coordinate. Moreover, local solutions become global if the usual H1 norm of velocity and L2\L4 norm of magnetic field are small enough. Here, the smallness assumptions are different on initial velocities and initial magnetic fields. Moreover, we don’t need to demand gradient of magnetic field to be small enough as that of velocities. So the initial magnetic filed can contain large oscillation
U, Leong-Hou. "Matching problems in large databases." Click to view the E-thesis via HKUTO, 2010. http://sunzi.lib.hku.hk/hkuto/record/B43910488.
Full textJonge, Dave de. "Negotiations over large agreement spaces." Doctoral thesis, Universitat Autònoma de Barcelona, 2015. http://hdl.handle.net/10803/295709.
Full textIn this thesis we investigate negotiation algorithms for domains with non-linear utility functions and where the space of possible agreements is so large that the application of exhaustive search is impossible. Furthermore, we explore the relationship between the fields of Automated Negotiations, Game Theory, Electronic Institutions, and Constraint Optimization. We present three case studies with increasing complexity. Firstly, we introduce an automated negotiator based on Genetic Algorithms, which is applied to a domain where the set of possible agreements is explicitly given as a vector space and, although the utility functions are non-linear, the utility value of any given deal can be calculated quickly by solving a linear equation. Secondly, we introduce a general purpose negotiation algorithm called NB3, which is based on Branch & Bound. We apply this to a new negotiation test case in which the value of any given deal can only be determined by solving an NP-hard problem. Our third case involves the game of Diplomacy, which is even harder than the previous test cases, because a given deal usually does not entirely x the agent's possible actions. The utility obtained by an agent thus also depends on the actions it performs after making the deal. Moreover, its utility also depends on the actions chosen by the other agents, so one needs to take Game Theoretical considerations into account. We argue that in this Game Theoretical model there no longer exists a satisfactory de nition of a reservation value, unlike the models commonly used in classical bargaining theory. Furthermore, we argue that negotiations require a mechanism, known as an Electronic Institution, to ensure that agreements are obeyed. One framework for the development of Electronic Institutions is EIDE and we introduce a new extension to EIDE that provides a user interface so that humans can interact within such Electronic Institutions. Moreover, we argue that in the future it should be possible for humans and agents to negotiate which protocols to follow in an Electronic Institution. This could be especially useful for the development of a new kind of social network in which the users can set the rules for their own private communities. Finally, we argue that the EIDE framework is too complicated to be used by average people who do not have the technical skills of a computer scientist. We therefore introduce a new language for the definition of protocols, which is very similar to natural language so that it can be used and understood by anyone.
Tsaprounis, Konstantinos. "Large cardinals and resurrection axioms." Doctoral thesis, Universitat de Barcelona, 2012. http://hdl.handle.net/10803/97038.
Full textLoeliger, Teddy. "Large-area photosensing in CMOS /." Zürich, 2001. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=14038.
Full textPetraglio, Gabriele Carlo Luigi. "Large scale motions in macromolecules /." Zürich : ETH, 2006. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=16786.
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