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VIRGILI, LUCA. "Graphs behind data: A network-based approach to model different scenarios." Doctoral thesis, Università Politecnica delle Marche, 2022. http://hdl.handle.net/11566/295088.
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Al giorno d’oggi, i contesti che possono beneficiare di tecniche di estrazione della conoscenza a partire dai dati grezzi sono aumentati drasticamente. Di conseguenza, la definizione di modelli capaci di rappresentare e gestire dati altamente eterogenei è un argomento di ricerca molto dibattuto in letteratura. In questa tesi, proponiamo una soluzione per affrontare tale problema. In particolare, riteniamo che la teoria dei grafi, e più nello specifico le reti complesse, insieme ai suoi concetti ed approcci, possano rappresentare una valida soluzione. Infatti, noi crediamo che le reti complesse possano costituire un modello unico ed unificante per rappresentare e gestire dati altamente eterogenei. Sulla base di questa premessa, mostriamo come gli stessi concetti ed approcci abbiano la potenzialità di affrontare con successo molti problemi aperti in diversi contesti. Nowadays, the amount and variety of scenarios that can benefit from techniques for extracting and managing knowledge from raw data have dramatically increased. As a result, the search for models capable of ensuring the representation and management of highly heterogeneous data is a hot topic in the data science literature. In this thesis, we aim to propose a solution to address this issue. In particular, we believe that graphs, and more specifically complex networks, as well as the concepts and approaches associated with them, can represent a solution to the problem mentioned above. In fact, we believe that they can be a unique and unifying model to uniformly represent and handle extremely heterogeneous data. Based on this premise, we show how the same concepts and/or approach has the potential to address different open issues in different contexts.
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Silva, Marcos Afonso da [UNESP]. "Análise complexa e aplicações." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/153862.
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Submitted by Marcos Afonso Da Silva (marcos.da.silvaaf@gmail.com) on 2018-05-02T18:35:06Z
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O objetivo principal deste trabalho é desenvolver um estudo introdutório, porém detalhado, sobre Análise Complexa e algumas de suas aplicações. Apresentamos o corpo dos números complexos, exploramos as funções complexas de uma variável complexa, exibimos parte da teoria das funções analíticas e parte da teoria de integração complexa. Provamos importantes resultados, tais como o Teorema de Cauchy, o Teorema de Taylor, o Teorema dos Resíduos, entre outros igualmente relevantes. Como aplicação da teoria, destacamos a utilização do Teorema dos Resíduos para determinar a transformada inversa de Laplace de uma função F(s).
The main objective of this work is to develop an introductory but detailed study on Complex Analysis and some of its applications. We present the field of the complex numbers, explore the complex functions of a complex variable, exhibit part of the theory of analytic functions, and part of the complex integration theory. We prove important results, such as Cauchy’s Theorem, Taylor’s Theorem, Residue Theorem, among others equally relevant. As an application of the theory, we highlight the use of the Residue Theorem to determine the inverse Laplace transform of a function F(s).
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Gontard, Sébastien. "Courbures de métriques invariantes dans les variétés complexes non compactes." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAM027/document.
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Nous étudions les relations entre des propriétés géométriques et des propriétés métriques dans les domaines de C^n.Plus précisément, nous nous intéressons au comportement des courbures bisectionnelles holomorphes de métriques de Kähler invariantes, la métrique de Bergman et la métrique de Kähler-Einstein, au voisinage du bord des domaines pseudoconvexe bornés à bord lisse.Nous prouvons qu'aux points de stricte pseudoconvexité ou tels que la fonction squeezing du domaine tend vers 1 les courbures bisectionnelles holomorphes de la métrique de Kähler-Einstein du domaine tendent vers les courbures bisectionnelles holomorphes de la métrique de Kähler-Einstein de la boule.Nous étudions également les courbures de la métrique de Kähler-Einstein et de la métrique de Bergman dans certains domaines polynomiaux (notamment les domaines tubes et les domaines de Thullen de C^2) qui servent de modèles locaux aux points du bord qui sont de type fini. A partir de ces études nous prouvons qu'en certains points du bord de domaines convexes bornés lisse de type fini dans C^2 il existe un voisinage non tangentiel tel que les courbures bisectionnelles holomorphes de la métrique de Kâhler-Einstein sont pincées négativement. Nous prouvons également que pour tout domaine pseudoconvexe borné de type fini qui est Reinhardt complet il existe un voisinage du bord relatif au domaine tel que les courbures bisectionnelles holomorphes de la métrique de Bergman sont comprises entre deux constantes strictement négativesWe study the relationships between geometric properties and metric properties of domains in C^n.More precisely, we are interested in the behavior of holomorphic bisectional curvatures of invariant Kähler metrics, namely the Bergman metric and the Kähler-Einstein metric, near the boundary of bounded pseudoconvex domains with smooth boundary.We prove that at boundary points that are either strictly pseudoconvex or such that the squeezing function of the domain tends to one the holomorphic bisectional curvatures of the Kähler-Einstein metric of the domain tends to the holomorphic bisectional curvatures of the Kähler-Einstein metric of the ball.We also study the holomorphic bisectional curvatures of the Kähler-Einstein metric and of the Bergman metric in some polynomial domains (namely tube and Thullen domains in C^2) which serve as local models at boundary point of finite type. Using these studies we prove that at certain boundary points of smoothly bounded convex domains of finite type there exists a non tangential neighbourhood such the holomorphic bisectional curvatures of the Kähler-Einstein metric are pinched between two negative constants. We also prove that for every smoothly bounded pseudoconvex complete Reinhardt domain of finite type inf C^2 there exists a neighbourhood of the boundary relative to the domain in which the holomorphic bisectional curvatures of the Bergman metric are pinched between two negative constants
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DA, SILVA PEREIRA DANIEL FILIPE. "Qualitative modelling of ecological systems: Extending calculation procedures and applications." Doctoral thesis, Università degli studi di Ferrara, 2020. http://hdl.handle.net/11392/2487971.
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The aim of this Ph.D. was to contribute to the discipline of ecosystems networks, in particular to loop analysis, by improving on the current algorithm implementations, with particular emphasis in developing an approach to couple systems quantitative information to the analytical processes of loop analysis, and through it allow the exploration the mechanism behind a systems responsiveness to perturbations, that is, the importance of both the variables, the structure of linkages between them and the intensity of those linkages.
In this thesis, after a presentation of the loop analysis and its main drawback, the inherent lack of associated link intensity and the repercussions these have on the system’s responsiveness, three chapters follow. In Chapter 3, the LevinsAnalysis R package is presented. In this package the improved code and its applications explained and demonstrated through the application of the package functions to a case study, the Savannah Fires (Bodini & Clerici, 2016) model. This case was specifically selected to demonstrate the potential of the package and its novel approach to identification of the importance of linkage strength and path analysis. In Chapter 4, I explore the Caspian Sea network prior to Mnemiopsis leidyi invasion, with the aim of investigating the mechanism behind the changes observed on multiple species and their importance compared with one another, the role that different species, the strength of interaction of the links and paths connecting them might have played in the system response to the different pressures it suffered. The result of this analysis, pointing to the importance of both kilkas and bony fish in the system’s response to perturbations such as overfishing. Phytoplankton also emerges as potentially playing an important role in the system, in particular a possible negative input on this variable seems to be of importance in describing the changes observed in the system. From this chapter also comes about how the strength of interplay between variables and from there the strength of pathways connecting the system play a central role in the Caspian Sea system and its response to press perturbations. In Chapter 5, a discussion is taken on the viability and potential use of loop analysis in the study of systems whose variables lay across the social and the ecological domains: species populations, predators and prey, but also governmental organizations, human dynamics and social mechanisms.Lo scopo di questo lavoro di dottorato è di contribuire allo sviluppo della scienza delle reti in ambito ecologico. In particolare il lavoro si focalizza sulla tecnica della loop analysis ampliandone le potenzialità dell’algoritmo implementato su piattaforma informatizzata introducendo un’estensione quantitativa dell’algoritmo di predizione. Lo scopo è quello di rendere più efficace la ricerca dei maccanismi alla base delle risposte degli ecosistemi agli eventi perturbativi. Dopo una presentazione della metodologia e dei suoi limiti, con particolare attenzione alla mancanza di quantificazione dei coefficienti di interazione tra le component dell’ecosistema la tesi si sviluppa in tre capitoli. Nel capitolo 3 è presentato il software “LevinsAnalysis”, che è stato sviluppato in ambiente R. Lo compongono diverse funzioni che consentono una più agevole applicazione dell’algoritmo previsionale a qualsiasi rete interattiva di tipo ecologico (e non solo). L’applicabilità di tali funzioni è sviluppata attraverso un caso di studio inerente l’ecologia degli ambienti di savana. Il Capitolo 4 è dedicato a una applicazione ecologica e riguarda lo studio della comunità del Mar Caspio finalizzato alla comprensione dei meccanismi che hanno generato le trasformazioni ecologiche osservate in quell’ecosistema, con particolare riferimento alla riduzione drastica di alcune specie ittiche e di mammiferi e all’esplosione degli organismi gelatinosi. Lo studio ha mostrato l’importanza di alcune componenti dal punto di vista dinamico, e ha consentito di formulare ipotesi causative sulle risposte dell’ecosistema alle perturbazioni, risposte che si ricavano dallo studio dei percorsi di interazione e della loro intensità. Il capitolo 5 è sostanzialmente un capitolo di discussione in cui si enfatizzano gli aspetti applicativi della loop analysis anche in contesti non strettamente ecologici, data la versatilità della tecnica. Così lo strumento diventa importante per analizzare sistemi socio-ecologici, che considerano, cioè, non solo variabili ecologiche come prede e predatori ma anche le interferenze di organizzazioni governative, e gli effetti delle dinamiche sociali.
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FICARA, Annamaria. "Social network analysis approaches to study crime." Doctoral thesis, Università degli Studi di Palermo, 2022. http://hdl.handle.net/10447/537005.
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Social Network Analysis (SNA) studies groups of individuals and can be applied in a lot of areas such us organizational studies, psychology, economics, information science and criminology. One of the most important results of SNA has been the definition of a set of centrality measures (e.g., degree, closeness, betweenness, or clustering coefficient) which can be used to identify the most influential people with respect to their network of relationships.
The main problem with computing centrality metrics on social networks is the typical big size of the data. From the computational point of view, SNA represents social networks as graphs composed of a set of nodes connected by another set of edges on which the metrics of interest are computed.
To overcome the problem of big data, some computationally-light alternatives to the standard measures, such as Game of Thieves or WERW-Kpath, can be studied. In this regard, one of my main research activities was to analyze the correlation among standard and nonstandard centrality measures on network models and real-world networks.
The centrality metrics can greatly contribute to intelligence and criminal investigations allowing to identify, within a covert network, the most central members in terms of connections or information flow. Covert networks are terrorist or criminal networks which are built from the criminal relationships among members of criminal organizations. One of the most renowned criminal organizations is the Sicilian Mafia.
The focal point of my research work was the creation of two real-world criminal networks from the judicial documents of an anti-mafia operation called Montagna conducted by a specialized anti-mafia police unit of the Italian Carabinieri in Messina (i.e., the third largest city on the island of Sicily). One network includes meetings and the other one records telephone calls among suspected criminals of two Sicilian Mafia families. This dataset is unique and it might represent a valuable resource for better understanding complex criminal phenomena from a quantitative standpoint.
Different SNA approaches have been used on these Montagna networks to describe their structure and functioning, to predict missing links, to identify leaders or to evaluate police interventions aimed at dismantling and disrupting the networks. Graph distances have been used to find a network model able to properly mime the structure of a Mafia network and to quantify the impact of incomplete data not only on Mafia networks such as the Montagna ones but also on terrorist and street gangs networks.
The two simple Montagna networks have been finally used to build a multilayer network trying to obtain a more nuanced understanding of the network structure and of the strategic position of nodes in the network.
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De, Poi Rossella. "Mass spectrometry as an emerging tool for the detection of proteins in complex matrices: from untargeted to targeted analysis." Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3425394.
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My PhD was performed in Mérieux NutriSciences, a company which provides analytical services. During my PhD I worked on three projects, whose common determinant was the application of mass spectrometry (MS) to the analysis of proteins. The main study deals with MS as a new tool for the analysis of food allergens. Food allergy is an important health problem involving immunological reactions that arise following exposure to protein allergens. In the absence of a cure, patients need to avoid the offending food to prevent allergic reactions. In the European Union, 14 allergens must be indicated in food labels when intentionally added. However, one of the main causes triggering allergic reactions is represented by undesired contamination of food by allergens in production facilities. Even tiny amounts of allergens can trigger severe manifestations; thus, to protect consumers sensitive analytical methods are required. Recently, methods based on MS have received increasing attention for the quantification of food allergens in complex matrices. In the present study, the development of a method based on MS for the simultaneous detection of egg, milk, tree nuts and peanuts allergens into bakery products is described. The method is based on the detection of specific peptides generated from the enzymatic hydrolysis of the target allergens and employs a technique called Multiple Reaction Monitoring, in which the mass spectrometer is operated to selectively acquire signals deriving from specific couples of m/z values, corresponding to a peptide ion and to one of its fragments. The method developed allows to detect target allergens in a specific way and with acceptable sensitivities and can be considered as a valuable alternative to other common analytical techniques, such as ELISA and PCR. A second topic of this thesis is bovine beta-casein, a polymorphic protein for which 12 genetic variants have been identified, the most common being A1 and A2. Some reports suggested a possible association between the consumption of A1 beta-casein and the etiology of some human diseases, including ischemic heart disease and diabetes. At the basis of the effects caused by A1 beta-casein there would be a bioactive peptide with opioid-like activity, released by proteolytic enzymes upon gastrointestinal digestion. This peptide, called beta-casomorphin-7, was shown to be produced only from certain beta-casein isoforms, having a histidine in position 67, including the A1 variant. On the other hand, variants possessing a proline in position 67, such as the A2 variant, would not be able to generate beta-casomorphin-7. Based on these assumptions, some companies now sell “A2 milk”, a milk containing only A2 beta-casein. In this project, a LC-MS analytical method was developed to discriminate between A2 milk and commercial milk, which typically contains a mixture of A1 and A2 beta-casein. The final purpose is to offer milk producers an analytical tool to certify that a milk labeled as “A2 milk” is really as such, eventually capable to identify possible frauds or contaminations. Finally, in this thesis a minor project is described, having as object the enzyme transglutaminase (TGase) from microbial origin. TGase catalyses the formation of isopeptide bonds between carboxamides of glutamine residues and amine groups of lysine, resulting in protein cross-linking. The action of TGase can determine significant changes in the physico-chemical properties of proteins, leading to changes in viscosity, thermal stability and elasticity. For these reasons, TGase finds application as an additive in the food industry. In this study a TGase from an unknown microbial source has been characterized and identified by applying a bottom-up proteomic approach. The identified enzyme is produced from a bacterial strain different from the one most commonly used in food industrial applications, S. mobaraense. Moreover, a method for the measurement of TGase enzymatic activity by the hydroxamate assay has been set up and has now become a service offered by the Mérieux NutriSciences.Il mio dottorato di ricerca si è svolto in Mérieux NutriSciences, un’ azienda che fornisce servizi analitici. Durante il mio periodo di dottorato ho lavorato su tre progetti, il cui determinante comune era l'applicazione della spettrometria di massa (SM) all'analisi delle proteine. Lo studio principale riguarda la SM applicata all'analisi degli allergeni alimentari. L'allergia alimentare è una patologia importante, dovuta a reazioni immunologiche che insorgono a seguito dell'esposizione di un soggetto ad allergeni proteici. Poiché ad oggi non esiste cura, per prevenire le reazioni allergiche i pazienti devono evitare di assumere alimenti contenenti allergeni. Nell'Unione Europea, 14 allergeni devono essere indicati sulle etichette degli alimenti se aggiunti intenzionalmente. Tuttavia, una delle principali cause di reazione allergica è rappresentata dalla contaminazione indesiderata degli alimenti con allergeni all'interno degli impianti di produzione. Anche piccole quantità di allergene possono scatenare gravi reazioni; dunque, per proteggere i consumatori sono necessari metodi analitici sensibili. Recentemente, i metodi basati sulla SM hanno ricevuto crescente attenzione per la quantificazione degli allergeni alimentari in matrici complesse. Nel presente studio viene descritto lo sviluppo di un metodo basato sulla SM per il rilevamento simultaneo di allergeni da uova, latte, arachidi e frutta secca in prodotti da forno. Il metodo si basa sull'identificazione di specifici peptidi generati dall'idrolisi enzimatica degli allergeni target ed impiega una tecnica chiamata Multiple Reaction Monitoring, in cui lo spettrometro di massa è utilizzato per acquisire selettivamente segnali derivanti da coppie di specifici valori m/z, corrispondenti a uno ione peptidico e ad uno dei suoi frammenti. Il metodo sviluppato consente di rilevare gli allergeni target in modo specifico e con sensibilità accettabile e può essere considerato una valida alternativa ad altre comuni tecniche analitiche, come l’ELISA e la PCR. Un secondo argomento trattato in questa tesi riguarda la beta-caseina bovina, una proteina polimorfica per la quale sono state identificate 12 varianti genetiche, fra cui le più comuni sono la A1 e la A2. Alcuni studi hanno suggerito una possibile associazione fra il consumo di beta-caseina A1 e l'eziologia di alcune malattie, tra cui l’ischemia cardiaca e il diabete. Alla base degli effetti causati dalla beta-caseina A1 ci sarebbe un peptide bioattivo con attività simil-oppiode, rilasciato da specifici enzimi proteolitici durante la digestione. Questo peptide, chiamato beta-casomorphin-7, viene generato solo a partire da alcune isoforme di beta-caseina, contenenti un'istidina in posizione 67, inclusa la variante A1. Al contrario, le varianti che possiedono una prolina in posizione 67, come la variante A2, non sarebbero in grado di generare il peptide beta-casomorphin-7. Sulla base di queste ipotesi, alcune aziende vendono ora il cosiddetto "latte A2", un tipo di latte contenente solo beta-caseina A2. In questo progetto di dottorato è stato sviluppato un metodo analitico LC-MS per discriminare il latte A2 dal latte commerciale, che tipicamente contiene una miscela di beta-caseina A1 e A2. Lo scopo finale è offrire ai produttori di latte uno strumento analitico per certificare che un latte etichettato come "latte A2" sia realmente tale, ed eventualmente in grado di identificare possibili frodi o contaminazioni. Infine, in questa tesi viene descritto un progetto che ha come oggetto l'enzima transglutaminasi (TGasi) di origine microbica. La TGasi catalizza la formazione di legami isopeptidici tra residui di glutammina e di lisina, determinando la formazione di cross-linking fra proteine. L'azione della TGasi può determinare cambiamenti significativi nelle proprietà fisico-chimiche delle proteine, portando a modifiche nella viscosità, nella stabilità termica e nella elasticità. Per questi motivi, la TGasi trova applicazione come additivo nell'industria alimentare. In questo studio, una specie di TGasi di origine microbica è stata caratterizzata e identificata applicando un approccio proteomico “bottom-up”. L'enzima identificato viene prodotto da un ceppo batterico diverso da quello più comunemente utilizzato nelle applicazioni industriali alimentari, denominato S. mobaraense. Infine, è stato sviluppato un metodo per la misurazione dell'attività enzimatica della TGasi mediante il saggio dell'idrossammato, che è ora diventato un servizio analitico offerto da Mérieux NutriSciences.
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Arnold, Rachel Florence. "Complex Analysis on Planar Cell Complexes." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/32230.
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This paper is an examination of the theory of discrete complex analysis that arises from the
framework of a planar cell complex. Construction of this theory is largely integration-based.
A combination of two cell complexes, the double and its associated diamond complex, allows
for the development of a discrete Cauchy Integral Formula.Master of Science
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RADICIONI, Tommaso. "All the ties that bind. A socio-semantic network analysis of Twitter political discussions." Doctoral thesis, Scuola Normale Superiore, 2021. http://hdl.handle.net/11384/109224.
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Social media play a crucial role in what contemporary sociological reflections define as a ‘hybrid
media system’. Online spaces created by social media platforms resemble global public
squares hosting large-scale social networks populated by citizens, political leaders, parties
and organizations, journalists, activists and institutions that establish direct interactions and
exchange contents in a disintermediated fashion. In the last decade, an increasing number
of studies from researchers coming from different disciplines has approached the study of the
manifold facets of citizen participation in online political spaces. In most cases, these studies
have focused on the investigation of direct relationships amongst political actors. Conversely,
relatively less attention has been paid to the study of contents that circulate during online
discussions and how their diffusion contributes to building political identities. Even more
rarely, the study of social media contents has been investigated in connection with those concerning
social interactions amongst online users. To fill in this gap, my thesis work proposes
a methodological procedure consisting in a network-based, data-driven approach to both
infer communities of users with a similar communication behavior and to extract the most
prominent contents discussed within those communities. More specifically, my work focuses
on Twitter, a social media platform that is widely used during political debates. Groups
of users with a similar retweeting behavior - hereby referred to as discursive communities -
are identified starting with the bipartite network of Twitter verified users retweeted by nonverified
users. Once the discursive communities are obtained, the corresponding semantic
networks are identified by considering the co-occurrences of the hashtags that are present in
the tweets sent by their members.
The identification of discursive communities and the study of the related semantic networks
represent the starting point for exploring more in detail two specific conversations that took
place in the Italian Twittersphere: the former occured during the electoral campaign before
the 2018 Italian general elections and in the two weeks after Election day; the latter
centered on the issue of migration during the period May-November 2019. Regarding the
social analysis, the main result of my work is the identification of a behavior-driven picture
of discursive communities induced by the retweeting activity of Twitter users, rather than
determined by prior information on their political affiliation. Although these communities
do not necessarily match the political orientation of their users, they are closely related to
the evolution of the Italian political arena. As for the semantic analysis, this work sheds light
on the symbolic dimension of partisan dynamics. Different discursive communities are, in
fact, characterized by a peculiar conversational dynamics at both the daily and the monthly
time-scale. From a purely methodological aspect, semantic networks have been analyzed by
employing three (increasingly restrictive) benchmarks. The k-shell decomposition of both
filtered and non-filtered semantic networks reveals the presence of a core-periphery structure
providing information on the most debated topics within each discursive community and
characterizing the communication strategy of the corresponding political coalition.
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Sadykov, Timour. "Hypergeometric functions in several complex variables." Doctoral thesis, Stockholm : Univ, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-198.
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Edwards, Samuel. "Complex Absorbing Potential Method: theory and implementation." Thesis, Uppsala universitet, Analys och tillämpad matematik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-171553.
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Sabourova, Natalia. "Real and complex operator norms." Licentiate thesis, Luleå : Luleå University of Technology, 2007. http://epubl.luth.se/1402-1757/2007/09.
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Inzoli, S. "EXPERIMENTAL AND STATISTICAL METHODS TO IMPROVE THE RELIABILITY OF SPECTRAL INDUCED POLARIZATION TO INFER LITHO-TEXTURAL PROPERTIES OF ALLUVIAL SEDIMENTS." Doctoral thesis, Università degli Studi di Milano, 2016. http://hdl.handle.net/2434/360596.
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The characterization of the shallow subsurface constitutes a challenging issue in several applications of science and engineering. Among the other disciplines, hydrogeophysics deals with the use of geophysical methods for the exploration, management, and monitoring of soil and groundwater. One of the main topics is the study of the petrophysical relationships between electrical properties and hydraulic conductivity, mainly through the dependence of such physical parameters on textural properties. The general aim of this work consists in an investigation of porous materials typical of alluvial environments with spectral induced polarization (SIP) method. The driving question of the research is the feasibility of the use of SIP to characterize both the textural assemblage of the sediments and the fluid properties, in presence of interacting effects related to particles’ mineralogy, organic matter, sediments’ fabric, etc. The samples’ set is constituted by 19 unconsolidated materials collected in four sites of the Po plain south of Milano (Orio Litta, Senna Lodigiana, and Landriano) and west of Milano (Lozzolo), and saturated with seven NaCl-water solutions with electrical resistivity varying from 0.9 Ωm to 315 Ωm. The textural composition of the samples varies between slightly-sandy mud and gravelly sand, and the porosity of the repacked samples between 0.26 and 0.63. The measurements are executed with an experimental system designed and realized at the Laboratory of Hydrogeophysics of the Università degli Studi di Milano. The resistivity amplitude and phase spectra are firstly modelled with single-relaxation models (Cole-Cole and generalized Cole-Cole) in a bounded low-frequency interval. Besides a traditional optimization based on the root-mean-square error, an original multi-optimization approach with separated amplitude and phase errors is tested to obtain a set of optimal solutions and an uncertainty interval for each model parameter, in order to avoid the misinterpretation of petrophysical relationships with scarcely reliable parameters. Significant relationships are identified between DC-resistivity and water resistivity, and between chargeability and mud content. The 10-based logarithm of the relaxation time is inversely correlated with a characteristic diameter of the sample. On the other hand, a Debye-decomposition, multi-relaxation model is applied to identify several polarization processes, characterized by different relaxation times, over the whole frequency interval. In order to maintain the whole spectral information also in the search for electrical-textural relationships, a combination of cluster analysis (CA) and principal component analysis (PCA) is adopted. This constitutes a new approach to relate spectral electrical behaviour to litho-textural properties, avoiding the selection of individual parameters or individual investigation frequency. The CA permits to classify the samples on the basis of their electrical behaviour, and the PCA allows to interpret the variability within the database in terms of a series of parameters ordered by importance. A textural characterization (characteristic diameters, gravel and mud contents, uniformity coefficients) is associated to each cluster, based on the characteristics of the corresponding samples. Analogously, a typical range of water resistivity is attributed to each cluster. This association of variability ranges of electrical and sedimentological properties is then used to infer the sediments’ properties of samples external to the input database, with satisfactory results. The high flexibility of the hierarchical clustering also allows evaluating the differences in the inferred properties according to the number of selected clusters. Finally, some preliminary SIP tests are performed in the field; field and laboratory results are not completely comparable, due to the differences in porosity, water content, and scale of investigation. However, some peculiar characters of the laboratory spectra are recognized in the corresponding field spectra, thus supporting a future application of the proposed methodology to interpret the resistivity amplitude and phase distribution in the subsurface.
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Olivier, Julien. "Fluides vitreux, sutures craniofaciales, diffusion réactive : quelques contributions à l'étude de ces systèmes multi-échelles ou singuliers." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00625455.
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On s'attache à étudier des modèles mathématiques multi-échelles pour des domaines variés : la rhéologie des matériaux vitreux, la biochimie dans la balnéothérapie et la biomécanique des sutures craniofaciales. Pour les matériaux vitreux, nous étudions un modèle de type cinétique et justifions mathématiquement des propriétés macroscopiques (transition vitreuse à faible cisaillement et comportement de type fluide newtonien à fort taux de cisaillement) après avoir remarqué une certaine analogie avec la pénalisation d'obstacles en mécanique des fluides. Nous proposons également une généralisation multi-dimensionnelle de ce modèle afin de prendre en compte des types d'écoulements généraux. En biochimie nous présentons un premier modèle très simplifié de réaction-diffusion et montrons comment concevoir un schéma numérique adapté en utilisant les hypothèses de modélisation. Enfin nous proposons un modèle de couplage biomécanique pour le développement des sutures qui rend compte du phénomène d'interdigitation que l'on observe en pratique.
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Persson, Aron. "The Automorphism Groups on the Complex Plane." Thesis, Umeå universitet, Institutionen för matematik och matematisk statistik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-139446.
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The automorphism groups in the complex plane are defined, and we prove that they satisfy the group axioms. The automorphism group is derived for some domains. By applying the Riemann mapping theorem, it is proved that every automorphism group on simply connected domains that are proper subsets of the complex plane, is isomorphic to the automorphism group on the unit disc.Automorfigrupperna i det komplexa talplanet definieras och vi bevisar att de uppfyller gruppaxiomen. Automorfigruppen på några domän härleds. Genom att applicera Riemanns avbildningssats bevisas att varje automorfigrupp på enkelt sammanhängande, öppna och äkta delmängder av det komplexa talplanet är isomorf med automorfigruppen på enhetsdisken.
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Lestrade, Kévin. "Simulation de trajectoires complexes à l’aide d’un hexapode de mouvement : application aux sports de glisse." Thesis, Paris, ENSAM, 2016. http://www.theses.fr/2016ENAM0037/document.
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Le projet SIMUSURF consiste en l’utilisation d’un robot hexapode de mouvement pour l’analyse de la réponse biomécanique d’un sujet positionné sur un plateau mobile et soumis à des mouvements de translation et/ou de rotation. Ce robot permet l’apprentissage d’activités sportives nécessitant des conditions particulières d’équilibre. Les sports de glisse tels que le surf, le ski ou le snowboard sont des activités qui nécessitent la conduite de trajectoire du support (planche de surf, skis ou snowboard) et l’équilibre du sportif. Pour un simulateur de surf, l’hexapode équipé de plates-formes de forces permettra alors d’établir des relations entre figures et réponse biomécanique du surfeur, d’étudier la variabilité interindividuelle pour exécuter un mouvement donné et d’optimiser le geste sportif dans un but d’aide à la performance.L’étude concernant le développement de ce simulateur à partir de l’hexapode a été abordée sous deux aspects.- D’un point de vue instrumentation et acquisition, la simulation des trajectoires correspondant aux mouvements de l’ensemble {surfeur + planche} sur l’eau a nécessité la constitution d’une base de données expérimentales permettant notamment d’identifier un modèle dynamique de comportement d’interactions entre le surfeur, sa planche et la vague. Pour ces mesures in situ, l’instrumentation d’une planche a été nécessaire. La conception d’une planche instrumentée et la mise en place d’un protocole d’acquisition dans les conditions extrêmes que représente l’environnement marin ont été un des verrous technologiques associés à ce projet.- D’un point de vue mécanique et robotique, il a été indispensable d’optimiser le pilotage de cette machine (au total 6 vérins avec des vitesses potentielles de 5 m/s) pour atteindre les trajectoires désirées ou les efforts multiaxiaux à imposer dans le cas particulier d’un pilotage complexe en effort.Afin d’être réaliste, un simulateur de surf réalisé autour d’un hexapode devait être capable de reproduire les mouvements complexes et de dynamiques élevées d’une planche de surf sur une vague et soumis aux efforts du surfeur. Ces performances ont été atteintes en tenant compte des phénomènes de couplage dynamiques existants entre ses actionneurs et en mettant en œuvre une approche de commande multivariable efficace : une approche CRONE permettant de synthétiser des lois de commande à la fois performantes et robustes, c’est-à-dire résistant à une connaissance imparfaite du système commandéThe project SIMUSURF consists in using an hexapod to analyze the biomechanical response of a human subject positioned on the moving platform of the hexapod and submitted to a translation and/or rotation movement. This robot allows practice of sport activities where balanced specific conditions are required. Riding sports such as surf, ski or snowboard are sports for which special skills to steer the support (surfboard, snowboard or ski for instance) are needed. The development of a surf simulator, using the hexapod equipped with multi-axis force plates, will allow to study the relations between figure and biomechanical response of the surfer, the interindividual variability to execute a given movement and to optimise the actions of the person aiming at better performances.The development of this simulator from the hexapod has been approached from two aspects.- From an instrumentation and acquisition point of view, simulation of the trajectories corresponding to the movements of the set {surfer + board} on the ocean required the constitution of an experimental database to identify such a behavioral dynamic model of the interactions between the surfer, his board and the wave. For these in situ experimentations, instrumentation of a surfboard was required. The design of an instrumented board and the implementation of an acquisition protocol in the extreme conditions due to the marine environment have been one of the technological hurdles associated.- From a mechanical and robotics point of view, it was essential to optimize the control of the hexapode (a total of 6 actuators with the potential speed of 5 m/s) to reach the desired trajectory or multiaxial efforts to impose in the special case of a force complex command.To be realistic, a surfing simulator designed with an hexapod had to be able to reproduce the complex movements and high dynamic of a surfboard on a wave and submitted to the efforts of surfer. These specifications were reached by taking account of existing dynamic coupling phenomena between actuators and implementing effective multivariable control approach: CRONE approach synthesizing control laws both powerful and robust, that is resistant to imperfect knowledge of the controlled system
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McQuaid, Michael James. "Spectroscopic characterization of metal-based complexes and metal-based complex oxidation processes." Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/30334.
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Cukic, Sonja. "Topological properties of complexes of graph homomorphisms." Licentiate thesis, KTH, Mathematics, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-329.
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Scremin, Greice. "TECIDO COMPLEXO FORMATIVO DOCENTE: REPERCUSSÕES DOS CONHECIMENTOS ESPECÍFICOS DAS ÁREAS NOS PROCESSOS FORMATIVOS DAS LICENCIATURAS." Universidade Federal de Santa Maria, 2014. http://repositorio.ufsm.br/handle/1/3479.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThis study is a doctorate s thesis and was performed in the research line 1 formation. Knowledges and profisional development, from Education Post Graduation Program of Federal University of Santa Maria (UFSM), Southern Brazil. This study arises from debates of in CNPq Reseach Group trajectories of Formation GTFORMA, concerned with formative way (personals and professionals) experienced by high level teachers. The general aim of this study was to analyse how specific knowledges repercute in teacher s formative processes. Paradigm of complexity under a case study research and following a qualitative methodology was used to give direction to this study, in which the investigations instruments were official documents (education laws and Licenciate Pedagogical Projects) and narrative interviewing carried out with teachers of UFSM Licenciate courses. Theoretical elements inrolled in this study were aligned to types of knowledges and competencies to be developed by teachers inicial courses, in order to promote a reflexion on veral reality aspects of these courses at UFSM context. Complex interpretative Analysis concept is presented as way of results analysis oriented by complexity principles and Morin s tetragram. It was possible to get to a complex comprehension about formative processes in licenciate courses based on referred analysis. A conceptual term, Teacher Formative Complex Tissue, was coined for getting to this understanding, evidencing that teacher formation needs to be conceived in its complexity at licenciate domains. Tissue is network intertwined by tree complex nets (Specific area net, Teacher s formative net, and Operative-formative net). In this study, interpretation presented has got involved through inter relacional dynamics among tree nets, rebuilded in each interaction. Complexity based on systemic thinking redirect the look to the analyzed reality for making possible the proposition of a new signification and to highlight the importance of rethinking this reality in a more integrated mode. Therephore, the Teacher Formative Complex Tissue is characterized by the incoherence between how teacher formation would be ideally and how efectivelly it is revealed by the study. So, comprehending two important dimensions of this process (official documents and teacher s discourse) in this study, allowed to show the way how the teacher formative process was understood from studied reality.
Este trabalho de tese de doutorado em Educação foi desenvolvido na Linha de Pesquisa 1 Formação, Saberes e Desenvolvimento Profissional, do Programa de Pós-graduação em Educação, da Universidade Federal de Santa Maria. Este estudo emerge a partir das discussões no grupo de pesquisa do CNPq Trajetórias de Formação GTFORMA, que tem suas preocupações voltadas para as trajetórias formativas (pessoais e profissionais) percorridas por docentes do nível superior. A pesquisa teve o objetivo geral de analisar como os conhecimentos específicos das áreas repercutem nos processos formativos nas licenciaturas. A metodologia utilizada esteve pautada no paradigma da complexidade sob uma abordagem qualitativa, de tipo estudo de caso em que os instrumentos da investigação foram documentos oficiais (legislação e Projetos Pedagógicos de Curso) e entrevistas narrativas realizadas com docentes dos cursos de licenciatura da UFSM. Os elementos teóricos envolvidos nesse trabalho dizem respeito aos conhecimentos, saberes e competências a serem desenvolvidos pelos cursos de formação inicial de professores, a fim de refletir sobre aspectos da realidade desses cursos, no contexto da UFSM. Apresenta-se como forma de análise dos resultados desse estudo o conceito de Análise Interpretativa Complexa que está pautada nos princípios descritores da Complexidade e no Tetragrama Organizacional. Com base nas análises realizadas, foi possível alcançar uma compreensão complexa acerca dos processos formativos nos cursos de licenciatura. Para essa compreensão, foi cunhado o termo Tecido Complexo Formativo Docente, evidenciando que a formação docente no campo das licenciaturas precisa ser compreendida em sua complexidade. O Tecido é entretecido por três Redes Complexas (Rede específica da área, Rede formativa docente e Rede operativa formativa). A interpretação apresentada nesse trabalho envolveu a dinâmica inter-relacional entre as três Redes, reconstruídas a cada interação. A complexidade fundamentada no pensamento sistêmico, direcionou o olhar para a realidade analisada, tornando possível propor novos significados e destacar a importância de repensá-la de modo mais integrado. O Tecido Complexo Formativo Docente caracteriza-se, portanto, por incoerências entre o modo como a formação docente deveria ser, idealmente, e como efetivamente é revelada na pesquisa. Desse modo, abarcar duas dimensões importantes desse processo de formação (documentos e discursos docentes), permitiu evidenciar o modo como o processo formativo docente foi entendido na realidade estudada.
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Leite, Daiani Canabarro. "Estudo teórico-experimental de complexo metálico de amilopectina." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2013. http://hdl.handle.net/10183/80418.
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Polímeros com funções quelantes têm sido amplamente encontrados no campo de separação e recuperação de íons metálicos de efluentes, sendo também utilizados na área de cosmetologia. O polímero utilizado neste trabalho foi obtido pela solubilização do Amidex 40003, amido geneticamente modificado contendo majoritariamente amilopectina, utilizando a mistura dimetilsulfóxido (DMSO)/H2O 90/10% v/v como solvente. O objetivo foi a formação de complexos de amilopectina com os íons metálicos Cr3+, Fe3+, Cu2+, Ni2+, Co2+ e Pb2+ nas formas de sais de acetato, nitrato e cloreto. O estudo buscou a otimização de alguns fatores considerados importantes para a obtenção de melhores rendimentos de reação, realizados através de um planejamento fatorial completo 23, nos quais as variáveis estudadas foram temperatura, tempo e massa do sal. Além disso, foram realizadas análises de pH, condutividade, infravermelho (FT-IR), UV-Visível (UV-Vis) e termogravimetria (TGA) para a comprovação dos complexos formados e para o estudo aprofundado das mudanças ocorridas nas características do polímero. O estudo também compreendeu a realização de cálculos ab initio utilizando a Teoria do Funcional da Densidade (DFT) com o intuito de entender a conformação da amilopectina no vácuo e em solvente implícito, obter um espectro vibracional teórico da amilopectina a fim de comparação com aquele obtido experimentalmente e, através do cálculo de cargas parciais, verificar os potenciais sítios de coordenação da amilopectina na complexação com o metal. Na primeira etapa experimental do trabalho foi verificado através do cálculo do efeito das variáveis que os fatores tempo e massa do sal devem ser mantidas no nível superior (+) e o fator temperatura deve ser mantido no nível inferior (-). As análises de pH, condutividade, FT-IR, UV-Vis e TGA evidenciaram a formação dos complexos devido às mudanças observadas antes e após a complexação. O estudo conformacional teórico da amilopectina revelou a importância dos efeitos estereoeletrônicos e a influência do conjunto de base utilizado no cálculo. O cálculo das cargas parciais mostrou que os prováveis sítios de coordenação da amilopectina são os oxigênios ligados ao C2 e C3, corroborando com dados da literatura. O espectro vibracional teórico apresentou resultados correlacionáveis com aqueles encontrados experimentalmente.Polymers with chelating functions have been widely found in the field of separation and recovery of metal ions from wastewater and are also used in the cosmetology area. The polymer used in this work was the Amidex 40003, a genetically modified starch containing mostly amylopectin, using the mixture dimethylsulfoxide (DMSO)/H2O 90/10% v/v as solvent. The purpose was the formation of amylopectin complexes with Cr3+, Fe3+, Cu2+, Ni2+, Co2+ and Pb2+ metal ions in the form of acetate, nitrate and chloride salts. The study sought to optimize some factors considered important for obtaining better reaction yields, carried out through a 23 full factorial design, which the variables studied were temperature, time and mass of salt. In addition, analysis of pH, conductivity, infrared (FT-IR), UV-Visible (UV-Vis) and thermogravimetry (TGA) were performed to prove the complexes formed and for detailed study of the changes in the polymer characteristics. The study also included the achievement of ab initio calculations using Density Functional Theory (DFT) in order to understand the amylopectin conformation in vacuum and implicit solvent, get a theoretical vibrational spectrum of amylopectin in order to compare with the one experimentally obtained and, through the partial charges calculation, check the potential amylopectin coordination sites in the complexation with the metal ion. In the first step of the experimental work was verified by variables effect calculations that time and mass of salt variables should be maintained at the higher level (+) and the temperature variable should be maintained at the lower level (-). Analysis of pH, conductivity, FT-IR, UV-Vis and TGA proved the complexes formation due to the changes observed before and after complexation. The theoretical conformational study of amylopectin showed the significance of stereo electronics effects and the influence of the basis set used in the calculation. Partial charges calculation showed that the probable amylopectin coordination sites are the oxygen atoms connected to C2 and C3, confirming literature data. The theoretical vibrational spectrum presented results comparable with those experimentally found.
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Parra, Rodrigo. "Equidistribution towards the Green current in complex dynamics." Doctoral thesis, KTH, Matematik (Inst.), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-34264.
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Given a holomorphic self-map of complex projective space of de-gree larger than one, we prove that there exists a finite collection oftotally invariant algebraic sets with the following property: given anypositive closed (1,1)-current of mass 1 with no mass on any element of this family, the sequence of normalized pull-backs of the current converges to the Green current. Under suitable geometric conditions on the collection of totally invariant algebraic sets, we prove a sharper equidistribution result.QC 20110530
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Coustaty, Mickaël. "Contribution à l'analyse complexe de documents anciens, application aux lettrines." Phd thesis, Université de La Rochelle, 2011. http://tel.archives-ouvertes.fr/tel-00691922.
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De nombreux projets de numérisation sont actuellement menés en France et en Europe pour sauvegarder le contenu de dizaines de milliers de documents anciens. Les images de ces documents sont utilisées par les historiens pour identifier l'historique des livres. Cette thèse s'inscrit dans le projet Navidomass (ANR-06-MDCA-012) qui a pour but de valoriser le patrimoine écrit français de la Renaissance, en proposant d'identifier ses images pour les indexer. Dans le cadre de cette thèse, nous nous sommes particulièrement intéressés aux images graphiques. Ces documents,qui sont apparus avec le début de l'imprimerie, sont composées d'images complexes puisque composées de différentes couches d'informations (images de traits).Afin de répondre à ce problème, nous proposons un modèle ontologique d'analyse complexe d'images de documents anciens. Ce modèle permet d'intégrer dans une même base les connaissances propres aux historiens, et les connaissances extraites par des traitements d'images. De par la nature complexe de ces images, les méthodes habituelles d'analyse d'images et d'extraction automatique de connaissances sont inopérantes. Nous proposons donc une nouvelle approche d'analyse des images de documents anciens qui permet de les caractériser à partir de leurs spécificités. Cette approche commence par simplifier les images en les séparant en différentes couches d'informations (formes et traits). Puis, pour chaque couche, nous venons extraire des motifs utilisés pour décrire les images. Ainsi, les images sont caractérisées à l'aide de sacs de motifs fréquents, et de sacs de traits. Pour ces deux couches d'informations, nous venons également extraire des graphes de régions qui permettent d'extraire une connaissance structurelle des images. La complexification de ces deux descriptions est insérée dans la base de connaissances, pour permettre des requêtes complexes. Le but de cette base est de proposer à l'utilisateur de rechercher une image en indiquant soit un exemple d'images recherchées, soit des éléments caractéristiques des images.
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Al-Lawati, Nabila J. M. "Analysis of complex antibiotics." Thesis, University of Brighton, 2012. https://research.brighton.ac.uk/en/studentTheses/6af329d7-a44a-4c05-bd26-5664eddcbb1c.
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The emergence of multidrug resistant Gram-negative bacteria such as Pseudomonas aeruginosa and Acinetobacter baumannii has been recognized worldwide and some clinical isolates of these bacteria are now resistant to most of the antibiotics currently available. Unfortunately, there are at present not enough new antimicrobial drugs being produced by the pharmaceutical industry to keep pace with the continuing development of antibiotic resistance. Colistin is an old antibiotic and in the form of colistin methanesulphonate sodium (CMS) has re-emerged as a major treatment for burn patients colonised with Acinetobacter baumannii. However, this antibiotic can lead to profound toxicity and for this reason the blood levels of CMS should be carefully monitored. Unfortunately the methods available for measuring it in serum are not robust and are not able to differentiate between the two forms of colistin i.e. colistin sulphate (CLS) and CMS. In this study the chemical (Thin Layer Chromatography and High Performance Liquid Chromatography) and microbiological methods for CLS and CMS analysis were investigated to develop a methodology for reproducible quantification of CLS and CMS in water or serum. Since CMS in aqueous solution has the potential to hydrolyze to produce a complex mixture of colistin sulphomethylated derivatives as well as colistin base, the optimized chemical and microbiological methods were used to determine the degradation of CLS or CMS in aqueous solution and serum. The bacteriostatic and bactericidal activity of CLS and CMS were probed by calculations of minimum inhibitory concentrations and time survivor studies. Depending on their concentrations, both antibiotics were found to exhibit bacteriostatic and bactericidal properties against a range of Gram-negative bacteria. Membrane damage caused by both forms of colistin was investigated using Acinetobacter lwoffii R46383 anddetennining intracellular potassium leakage and 260nm absorbing materials leakage. CLS was shown to cause substantial membrane damage, indicated by rapid, gross potassium leakage, while the effect of CMS on the membrane appeared to be more subtle, with cells exhibiting a more concentration dependent loss of potassium. Adsorption isotherms ofCLS gave results that were indicative of high affmity isotherm (H- shape), while adsorption isotherms of CMS were indicative of co-operative sorption (S- shape). Investigations into CLS and CMS cytotoxicity were performed using normal rat kidney (NRK-52E) cell line; the investigations revealed that neither forms of colistin has a major adverse effect on the rat renal cells even at concentrations higher than the therapeutic doses.
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Friol, Natália Rizzo. "Filogenia e evolução das espécies do gênero Phrynops (Testudines, Chelidae)." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/41/41133/tde-09032015-083240/.
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O gênero Phrynops abrange quatro espécies válidas, incluindo o complexo da espécies Phrynops geoffroanus, e apresenta uma filogenia historicamente mal compreendida. Esse projeto objetivou estudar este gênero, com ênfase especial nas populações de P. geoffroanus, através de análises morfométricas, morfológicas, osteológicas e moleculares, a fim de entender sua taxonomia e definir suas relações filogenéticas. Para tanto, foram coletados e emprestados espécimes das populações de P. geoffroanus de dez bacias hidrográficas brasileiras, além de P. tuberosus, P. williamsi e P. hilarii para compôr a análise. A partir disso, foi feita uma análise morfométrica linear dos espécimes das populações de P. geoffroanus, bem como uma comparação do padrão de coloração desses indivíduos com o intuito de definir as populações taxonomicamente distintas dentro da área de distribuição da espécie. Para as análises filogenéticas, foram preparados esqueletos completos e sequenciados os genes 12S, cytb, ND4, R35 e Rag 2 das espeçies de Phrynops e do seu grupo externo, considerando todos os gêneros e quase todas as espécies de Chelidae, bem como representantes de Podocnemididae e Pelomedusidae. Foram conduzidos três conjuntos distintos de análises filogenéticas com os dados moleculares e morfológicos obtidos durante este estudo: 1) uma análise de parcimônia da matriz morfológica; 2) uma análise de máxima verossimilhança das sequências moleculares; 3) uma análise de parcimônia dos dados morfológicos e moleculares concatenados. Como resultados, os dados morfométricos e osteológicos mostram que a população de P. geoffroanus da bacia do rio Paraná representa uma espécie nova, distinta das demais populações pertencentes ao complexo geoffroanus. Além disso, a população de P. geoffroanus do Rio Doce é claramente distinta das demais populações nas hipóteses moleculares. O exemplar de P. williamsi do Rio Iguaçu se distingue molecularmente do clado formado pelos demais exemplares de P. williamsi do Rio do Peixe. Os dados morfológicos e moleculares concatenados mostram que o gênero Phrynops representa um grupo monofilético. As populações de P. geoffroanus apresentaram evidências de agrupamento por bacias. Nas análises moleculares e concatenadas, P. hilarii se posiciona dentro do clado formado pelas populações de P. geoffroanus. O conjunto de dados osteológicos posiciona Mesoclemmys como grupo-irmão de Phrynops, porém, no conjunto de dados moleculares Phrynops aparece como grupo-irmão dos demais gêneros, exceto Hydromedusa e Chelus que encontram-se em uma posição mais basal nessa hipótese. Desta forma, não foi possível definir com clareza o grupo-irmão do gênero Phrynops neste estudo. Os caracteres osteológicos e moleculares evidenciaram Mesoclemmys como um grupo parafilético, pela não inclusão de Mesoclemmys hogei nesse gênero. Por fim, neste estudo, fica evidente que P. geoffroanus e P. tuberosus pertencem à calha norte do rio Amazonas e não se distinguem através do conjunto de dados osteológicos e morfométricos empregados aqui. Entretanto, uma amostragem das localidades específicas será necessária para definir objetivamente o status taxonômico de P. tuberosusThe genus Phrynops covers four valid species, including the species complex Phrynops geoffroanus. The genus has a confuse and poorly resolved taxonomic and phylogenetic history. This project aimed to study the genus Phrynops, with particular emphasis on populations of P. geoffroanus and P. tuberosus, through morphometric, morphological, osteological and molecular analyzes, in order to understand their taxonomy and provide a phylogenetic hypothesis for their interrelationships. Specimens representing populations of P. geoffroanus from ten Brazilian river basins, as well as P. tuberosus, P. williamsi and P. hilarii, were collected or loaned from institutions. A linear morphometric analysis and comparison of color patterns were performed in individuals belonging to the populations of P. geoffroanus in order to define taxonomically distinct populations within the range of the species. For the phylogenetic analyzes, complete skeletons were prepared and tissue samples were sequenced for the genes 12S, cytb, ND4, R35 and Rag 2, for most species of Phrynops and its outgroup taxa, considering all genera and almost all species of Chelidae, as well as representatives of Podocnemididae and Pelomedusidae. Three distinct sets of phylogenetic analyzes were performed with the molecular and morphological data obtained during this study:1) a parsimony analysis of the morphological matrix;2) a maximum likelihood analysis of molecular sequences;3) a parsimony analysis of the combined morphological and molecular data. As a result, the morphometric and osteological data show that the population of P. geoffroanus from the Paraná River basin is a distinct species, and therefore new. The population of P. geoffroanus from the Doce River is clearly distinct from other populations in the molecular hypotheses. The specimen of P. williamsi from the Iguaçu River separates molecularly from the clade formed by the remaining populations of P. williamsi from the Peixe River. The combined morphological and molecular data show that the genus Phrynops corresponds to a well supported monophyletic group.The sampled populations of P. geoffroanus showed evidence of grouping by distinct river basins. In both molecular and combined analyzes, P. hilarii is rooted within the clade formed by the populations of P. geoffroanus. The set of skeletal data supports Mesoclemmys as the sister group of Phrynops, while the molecular data set shows Phrynops as the sister group of a clade composed by all the remaining genera, except Hydromedusa and Chelus that are positioned more basally in the tree. Therefore, the present analysis failed to define without ambiguity the sister-group relationship of the genus Phrynops. Both osteological and molecular datasets showed Mesoclemmys as a paraphyletic group, with the exclusion of Mesoclemmys hogei from the genus. Finally, it seems evident that P. tuberosus and P. geoffroanus belong to the north region of the Amazon River and are not distinguishable by the set of osteological and morphometric data used in the present study. However, a larger sampling of specific locations will be required to objectively define the taxonomic status of P. tuberosus
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Di, Mauro Gianmarco 1985. "Functional analysis of the extraproteasomal ubiquitin receptor Dsk2/UBQLN in Drosophila and human cells." Doctoral thesis, Universitat Pompeu Fabra, 2019. http://hdl.handle.net/10803/666204.
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Dsk2/UBQLN is a conserved extraproteasomal ubiquitin receptor that has been widely described as a protein involved in the ubiquitin proteasome pathway. In Drosophila, this protein has been recently reported in a non-proteolitic function as part of the dHP1c transcription complex together with the zinc finger proteins WOC and ROW, and the heterocromatin protein HP1c. Here we show that the dHP1c complex present a specific functional organization with WOC playing a direct role in the recruitment of dDsk2 to the nuclear compartment. This interaction results in the formation of a WOC-dDsk2 sub-complex that is able to bind chromatin only through ROW. Moreover, we show that UBQLN1, which is the human homologue that shares the highest degree of similarity with dDsk2, is not able to bind chromatin when ectopically expressed in Drosophila and in human-derived cell lines endogenous UBQLN1 is not found associated with chromatin.Dsk2/UBQLN es un receptor extraproteasomal de ubiquitina altamente conservado que se ha descrito ampliamente como una proteína involucrada en la vía ubiquitina-proteasoma. En Drosophila, se ha descrito recientemente una función no proteolítica para Dsk2 como parte del complejo de transcripción dHP1c conjuntamente con las proteínas “zinc finger” WOC y ROW y la proteína de heterocromatina HP1c. Aquí mostramos que el complejo transcripcional dHP1c tiene una organización funcional, en la que WOC desempeña un papel directo en el reclutamiento de dDsk2 al compartimento nuclear. Esta interacción da como resultado la formación de un sub-complejo estable WOC-dDsk2 que es capaz de unirse a la cromatina solo a través de ROW. Además, mostramos que UBQLN1, que es el homólogo humano que comparte el mayor grado de similitud con dDsk2, no es capaz de unirse a la cromatina cuando se expresa ectópicamente en Drosophila y, en líneas celulares humanas, UBQLN1 no se asocía con la cromatina.
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Bravo, Francini Garcia. "Evolução do modelo de jogo nas categorias de base do voleibol feminino." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/39/39134/tde-28102015-073250/.
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O objetivo desse trabalho foi observar a evolução do modelo de jogo entre as categorias de base do voleibol feminino, analisando como cada categoria conquista o ponto e a como as variantes das ações de jogo que antecedem o ataque influenciam no seu desempenho no complexo I. Foram analisados três jogos das quatro melhores equipes classificadas da categoria infantil, infanto-juvenil e juvenil feminino, participantes do quadrangular final do Campeonato Metropolitano de São Paulo em 2009 organizado pela FPV. A coleta de dados foi realizada pelo sistema de vídeo. A análise dos dados comportou a estatística descritiva, pela obtenção de frequências e porcentagens, e a estatística inferencial pelo recurso ao Qui-quadrado e ao Phi de Cramer, no sentido de verificar a possível relação de dependência entre as vaiáveis do estudo. Através da análise descritiva observamos que a categoria infantil conquista mais pontos com o erro do adversário e as categorias infanto-juvenil e juvenil conquistam mais pontos com a ação de ataque. Com o avanço de categoria observamos uma tendência de aumento na recepção perfeita, na utilização do levantamento com toque em suspensão, do ataque contra um bloqueio duplo quebrado, na realização do ataque pela zona 2 bem como, um aumento na ocorrência dos ataques de 1º e 2º tempo e do ataque ponto. Assim como, uma diminuição na utilização do toque sem salto para o levantamento, dos ataques contra um bloqueio duplo compacto, da utilização dos ataques de 3º tempo e dos ataques que proporcionam a continuação do rally. Pela análise inferencial observamos uma relação de dependência estatisticamente significante do resultado do ataque com o resultado da recepção, a zona de levantamento, a técnica de levantamento, o resultado do levantamento, bem como com a zona de ataque, o tempo de ataque e tipo de ataque para todas as categoriasThe main purpose of this study was to determine game model evolution on female volleyball under-age divisions. It was analyzed how each category wins the point and how the game actions that occur before the attack affects the performance on complex I. We analyzed three games of the four best ranked female teams in infantil, infanto-juvenil and juvenil divisions, participants of the city of São Paulo Championship in 2009. The data base was captured using video system. Data analysis included descriptive statistics, by obtaining frequencies and percentages, and inferential statistics by using chi- square and Phi Cramer, in order to verify the possible relationship of dependency between the study variables. Descriptive analysis revealed that the infantil division obtain more points with the errors of the opponent and the infanto-juvenil and juvenil divisions obtain more points with the attack. As players advance through the age divisions, there is a trend toward increasing the occurrence of perfect receptions, the use of jump sets, the attack against a broken double block, the attack in zone 2 as well as an increase in the occurrence of attacks of 1st and 2nd tempo and the attack point. Moreover, we observed a decrease in the use of overhead set without jump, attack against a compact double block, the use of 3rd tempo attack and attack that provide continued rally. For the inferential analysis we observed a statistically significant relationship of dependency between attack result and the serve reception result, the set zone, set technique, the result of the set, as well as the attack zone, the attack tempo and type of attack for all categories
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Labonde, Jean-Marc. "Analyse complexe." Paris 11, 1985. http://www.theses.fr/1985PA112358.
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On étudie dans cette thèse une nouvelle famille d’ensembles pics pour A(Un). La méthode utilisée consiste à construire des fonctions pics sur les compacts étudiés : elle reprend en les adaptant au polydisque des arguments développés par divers auteurs dans le cadre des domaines strictement pseudoconvexes. On donne également, en utilisant les mêmes techniques une caractérisation des ensembles de pics pour A∞(Un). Les résultats obtenus pour A (Un) permettent ensuite de mettre en évidence des compacts de mesure nulle pour certaines familles de mesures sur IRn et Tn. On retrouve en particulier parmi ces compacts les ensembles pics de la partie précédenteWe study in this thesis a new family of peak sets for A(Un). The used method consists in explicit construction of peak functions on the studied compacts: it takes again, adapting them to the polydisc, some arguments exposed by various author within strictly pseudoconvex domains. We also give, using the same technics, a characterization of peaks sets for A∞(Un). The results obtained for A(Un) enable us to obtain some sets of measure zero for some measures on IRn and Tn. We recognize particularly among these compacts the peak sets of the preceding part
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Mougenot, Pierre. "Etude theorique ab initio scf et ci de complexes organometalliques binucleaires." Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13025.
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Analyse approfondie du spectre photoelectronique se(fe(c::(5)h::(5)))::(2)(no)::(2). Etude critique des resultats experimentaux anterieurs concernant le diamagnetisme suppose se(co(c::(5)h::(5)))::(2)(no)::(2). Bon accord avec l'experience dans l'etude theorique de l'etat fondamental du cation dirhodium tetraacetate dihydrate. Etude sur la nature de l'interaction metal-metal dans (v(c::(5)h::(5)))::(2) (c::(8)h::(8))
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Memon, Sohail Ahmed. "Mathematical modelling of complex dynamics." Thesis, University of Central Lancashire, 2017. http://clok.uclan.ac.uk/20497/.
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Soft materials have a wide range of applications, which include the production of masks for nano–lithography, the separation of membranes with nano–pores, and the preparation of nano–size structures for electronic devices. Self–organization in soft matter is a primary mechanism for the formation of structure. Block copolymers are long chain molecules composed of several different polymer blocks covalently bonded into a single macromolecule, which belong to an important class of soft materials which can self–assemble into different nano–structures due to their natural ability to microphase separate. Experimental and theoretical studies of block copolymers are quite challenging and, without computer simulations, it is difficult and problematic to analyse modern experiments. The Cell Dynamics Simulation (CDS) technique is a fast and accurate computational technique, which has been used to investigate block copolymers. The stability has been analysed by making use of different discrete Laplacian operators using well–chosen time steps in CDS. This analysis offers stability conditions for phase–field, based on the Cahn–Hilliard Cook (CHC) equations of which CDS is the finite difference approximation. To overcome grid related artefacts (discretization errors) in the computational grid, the study has been done for employing an isotropic Laplacian operator in the CDS framework. Several 2D and 3D discrete Laplacians have been quantitatively compared for their isotropy. The novel 2D 9–point BV(D2Q9) isotropic stencil operators have been derived from the B.A.C. van Vlimmeren method and their isotropy measure has been determined optimally better than other exiting 2D 9–point discrete Laplacian operators. Overall, the stencils in 9–point family Laplacians in 2D and the 19–point stencil operators in 3D have been found to be optimal in terms of isotropy and time step stability. Considerable implementation of Laplacians with good isotropy has played an important role in achieving a proper structure factor in modelling methods of block copolymers. The novel models have been developed by implementing CDS via more stable implicit methods, including backward Euler, Crank–Nicolson (CN) and Alternating Direction Implicit (ADI) methods. The CN scheme were implemented for both one order and two order parameter systems in CDS and successful results were obtained compared to forward Euler method. Due to the implementation of implicit methods, the CDS has achieved second–order accuracy both in time and space and it has become stronger, robust and more stable technique for simulation of the phase–separation phenomena in soft materials.
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Zymonopoulou, Maria-Isavella. "Sections of complex convex bodies." Diss., Columbia, Mo. : University of Missouri-Columbia, 2008. http://hdl.handle.net/10355/5528.
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Thesis (Ph. D.)--University of Missouri-Columbia, 2008.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on June 18, 2009) Vita. Includes bibliographical references.
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Zhu, Yueying. "Investigation on uncertainty and sensitivity analysis of complex systems." Thesis, Le Mans, 2017. http://www.theses.fr/2017LEMA1021/document.
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Par un développement en série de Taylor, une relation analytique générale est établie pour calculer l’incertitude de la réponse du modèle, en assumant l'indépendance des entrées. En utilisant des relations de puissances et exponentielles, il est démontré que l’approximation souvent utilisée permet d’évaluer de manière satisfaisante l’incertitude sur la réponse du modèle pourvu que l’incertitude d’entrée soit négligeable ou que le modèle soit presque linéaire. La méthode est appliquée à l’étude d’un réseau de distribution électrique et à un modèle d’ordre économique.La méthode est étendue aux cas où les variables d’entrée sont corrélées. Avec la méthode généralisée, on peux déterminer si les corrélations d'entrée doivent ou non être considérées pour des applications pratiques. Des exemples numériques montrent l'efficacité et la validation de notre méthode dans l'analyse des modèles tant généraux que spécifiques tels que le modèle déterministe du VIH. La méthode est ensuite comparée à celle de Sobol. Les résultats montrent que la méthode de Sobol peut surévaluer l’incidence des divers facteurs, mais sous-estimer ceux de leurs interactions dans le cas d’interactions non linéaires entre les paramètres d’entrée. Une modification est alors introduite, aidant à comprendre la différence entre notre méthode et celle de Sobol. Enfin, un modèle numérique est établi dans le cas d’un jeu virtuel prenant en compte la formation de la dynamique de l'opinion publique. L’analyse théorique à l’aide de la méthode de modification d'un paramètre à la fois. La méthode basée sur l'échantillonnage fournit une analyse globale de l'incertitude et de la sensibilité des observationsBy means of taylor series expansion, a general analytic formula is derived to characterise the uncertaintypropagation from input variables to the model response,in assuming input independence. By using power-lawand exponential functions, it is shown that the widelyused approximation considering only the first ordercontribution of input uncertainty is sufficiently good onlywhen the input uncertainty is negligible or the underlyingmodel is almost linear. This method is then applied to apower grid system and the eoq model.The method is also extended to correlated case. Withthe extended method, it is straightforward to identify theimportance of input correlations in the model response.This allows one to determine whether or not the inputcorrelations should be considered in practicalapplications. Numerical examples suggest theeffectiveness and validation of our method for generalmodels, as well as specific ones such as thedeterministic hiv model.The method is then compared to Sobol’s one which isimplemented with sampling based strategy. Resultsshow that, compared to our method, it may overvaluethe roles of individual input factors but underestimatethose of their interaction effects when there arenonlinear coupling terms of input factors. A modificationis then introduced, helping understand the differencebetween our method and Sobol’s one.Finally, a numerical model is designed based on avirtual gambling mechanism, regarding the formation ofopinion dynamics. Theoretical analysis is proposed bythe use of one-at-a-time method. Sampling-basedmethod provides a global analysis of output uncertaintyand sensitivity
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Lopez, Jean Pierre Huertas. "Análise de dados utilizando a medida de tempo de consenso em redes complexas." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/55/55134/tde-12052011-112532/.
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Redes são representações poderosas para muitos sistemas complexos, onde vértices representam elementos do sistema e arestas representam conexões entre eles. Redes Complexas podem ser definidas como grafos de grande escala que possuem distribuição não trivial de conexões. Um tópico importante em redes complexas é a detecção de comunidades. Embora a detecção de comunidades tenha revelado bons resultados na análise de agrupamento de dados com grupos de diversos formatos, existem ainda algumas dificuldades na representação em rede de um conjunto de dados. Outro tópico recente é a caracterização de simplicidade em redes complexas. Existem poucos trabalhos nessa área, no entanto, o tema tem muita relevância, pois permite analisar a simplicidade da estrutura de conexões de uma região de vértices, ou de toda a rede. Além disso, mediante a análise de simplicidade de redes dinâmicas no tempo, é possível conhecer como vem se comportando a evolução da rede em termos de simplicidade. Considerando a rede como um sistema dinâmico de agentes acoplados, foi proposto neste trabalho uma medida de distância baseada no tempo de consenso na presença de um líder em uma rede acoplada. Utilizando essa medida de distância, foi proposto um método de detecção de comunidades para análise de agrupamento de dados, e um método de análise de simplicidade em redes complexas. Além disso, foi proposto uma técnica de construção de redes esparsas para agrupamento de dados. Os métodos têm sido testados com dados artificiais e reais, obtendo resultados promissoresNetworks are powerful representations for many complex systems, where nodes represent elements of the system and edges represent connections between them. Complex networks can be defined as graphs with no trivial distribution of connections. An important topic in complex networks is the community detection. Although the community detection have reported good results in the data clustering analysis with groups of different formats, there are still some dificulties in the representation of a data set as a network. Another recent topic is the characterization of simplicity in complex networks. There are few studies reported in this area, however, the topic has much relevance, since it allows analyzing the simplicity of the structure of connections between nodes of a region or connections of the entire network. Moreover, by analyzing simplicity of dynamic networks in time, it is possible to know the behavior in the network evolution in terms of simplicity. Considering the network as a coupled dynamic system of agents, we proposed a distance measure based on the consensus time in the presence of a leader in a coupled network. Using this distance measure, we proposed a method for detecting communities to analyze data clustering, and a method for simplicity analysis in complex networks. Furthermore, we propose a technique to build sparse networks for data clustering. The methods have been tested with artificial and real data, obtaining promising results
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Ha, Dinh Truc. "Line outage vulnerabilities of power systems : models and indicators." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAT018/document.
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La vulnérabilité des systèmes électriques est l'un des problèmes liés à leur complexité. Il a fait l’objet d’une attention croissante des chercheurs au cours des dernières décennies. Malgré cela, les phénomènes fondamentaux qui régissent la vulnérabilité du système ne sont pas encore bien compris.Comprendre comment la vulnérabilité des réseaux électriques émerge de leur topologie est la motivation principale du présent travail. Pour cela, le présent travail de recherché propose une nouvelle méthode pour évaluer la vulnérabilité des systèmes électriques et identifier leurs éléments les plus critiques. La méthode permet d’avoir une bonne compréhension des liens entre la topologie d’un réseau et sa vulnérabilité à des pertes d’ouvrages (lignes ou transformateurs).La première partie de ce travail consiste en une analyse critique des approches rencontrées dans la littérature, s’appuyant sur la théorie des graphes, pour analyser la vulnérabilité des réseaux électriques. Les résultats fournis par ces approches pour quatre réseaux IEEE sont comparés à ceux fournis par une analyse de contingence de référence, basée sur une résolution d’un load-flow AC. Des avantages et inconvénients de chaque approche est tirée une méthode améliorée pour l'évaluation de la vulnérabilité des réseaux électriques aux pertes d’ouvrage. Cette méthode est basée sur une approximation courant continue du load flow.La deuxième partie propose une nouvelle approche basée sur la théorie spectrale des graphes et son utilisation pour la résolution d’un load flow DC. Elle permet de mieux comprendre comment la vulnérabilité des réseaux électriques et leurs composants critiques émergent de la topologie du graphe sous-jacent au réseauThe vulnerability of electrical systems is one of the problems related to their complexity. It has received increasing attention from researchers in recent decades. Despite this, the fundamental phenomena that govern the vulnerability of the system are still not well understood.Understanding how the vulnerability of power systems emerges from their complex organization is, therefore, the main motivation of the present work. It proposes the definition of a standard method to assess the vulnerability of power systems and identify their most critical elements. The method enables a better understanding of the links between the topology of the grid and the line outage vulnerabilities.The first part of this research work offers a critical review of literature approaches used to assess system vulnerability. The results provided by these approaches for four IEEE test systems are confronted to a reference contingency analysis using AC power flow calculations. From these analyses, pros and cons of each approach are outlined. An improved method for assessment of system vulnerability to line outages is defined from this confrontation. It is based on DC load flow and graph theory.The second part proposes a new approach based on spectral graph theory and solving of DC power flow to identify how system vulnerability and critical components emerge from the power network topology
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Alexandersson, Per. "On eigenvalues of the Schrödinger operator with a complex-valued polynomial potential." Licentiate thesis, Stockholms universitet, Matematiska institutionen, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-52064.
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In this thesis, we generalize a recent result of A. Eremenko and A. Gabrielov on irreducibility of the spectral discriminant for the Schroedinger equation with quartic potentials. In the first paper, we consider the eigenvalue problem with a complex-valued polynomial potential of arbitrary degree d and show that the spectral determinant of this problem is connected and irreducible. In other words, every eigenvalue can be reached from any other by analytic continuation. We also prove connectedness of the parameter spaces of the potentials that admit eigenfunctions satisfying k > 2 boundary conditions, except for the case d is even and k = d/2. In the latter case, connected components of the parameter space are distinguished by the number of zeros of the eigenfunctions. In the second paper, we only consider even polynomial potentials, and show that the spectral determinant for the eigenvalue problem consists of two irreducible components. A similar result to that of paper I is proved for k boundary conditions.
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Alotaibi, Abdullah Mathker. "Complex analysis using Nevanlinna theory." Thesis, University of Nottingham, 2005. http://eprints.nottingham.ac.uk/13793/.
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In this thesis, we mainly worked in the following areas: value distributions of meromorphic functions, normal families, Bank-Laine functions and complex oscillation theory. In the first chapter we will give an introduction to those areas and some related topics that are needed. In Chapter 2 we will prove that for a meromorphic function f and a positive integer k, the function af(f(k))n -1, n ≥ 2, has infinitely many zeros and then we will prove that it is still true when we replace f(k) by a differential polynomial. In Chapter 3 we will prove that for a merornorphic function f and a positive integer k, the function af f(k) -1 with N1(r, 1/f^((k)) ) = S(r, f) has infinitely many zeros and then we will prove that it is still true when we replace f(k) by a differential polynomial. In Chapter 4 we will apply Bloch's Principle to prove that a family of functions meromorphic on the unit disc B(0, 1), such that f(f1)m≠ 1, m ≠ 2, is normal. Also we will prove that a family of functions meromorphic on B(0,1), such that each f ≠ 0 and f(f(k))m ,k, m ∈N omits the value 1, is normal. In the fifth chapter we will generalise Theorem 5.1.1 for a sequence of distinct complex numbers instead of a sequence of real numbers. Also, we will get very nice new results on Bank-Laine functions and Bank-Laine sequences. In the last chapter we will work on the relationship between the order of growth of A and the exponent of convergence of the solutions y(k) +Ay =0, where A is a transcendental entire function with ρ(A) < 1/2.
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Boyer, Lee Christian. "Analysis of a Bap31 complex." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0035/MQ64325.pdf.
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Alexandersson, Per. "Combinatorial Methods in Complex Analysis." Doctoral thesis, Stockholms universitet, Matematiska institutionen, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-88808.
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The theme of this thesis is combinatorics, complex analysis and algebraic geometry. The thesis consists of six articles divided into four parts. Part A: Spectral properties of the Schrödinger equation This part consists of Papers I-II, where we study a univariate Schrödinger equation with a complex polynomial potential. We prove that the set of polynomial potentials that admit solutions to the Schrödingerequation is connected, under certain boundary conditions. We also study a similar result for even polynomial potentials, where a similar result is obtained. Part B: Graph monomials and sums of squares In this part, consisting of Paper III, we study natural bases for the space of homogeneous, symmetric and translation-invariant polynomials in terms of multigraphs. We find all multigraphs with at most six edges that give rise to non-negative polynomials, and which of these that can be expressed as a sum of squares. Such polynomials appear naturally in connection to expressing certain non-negative polynomials as sums of squares. Part C: Eigenvalue asymptotics of banded Toeplitz matrices This part consists of Papers IV-V. We give a new and generalized proof of a theorem by P. Schmidt and F. Spitzer concerning asymptotics of eigenvalues of Toeplitz matrices. We also generalize the notion of eigenvalues to rectangular matrices, and partially prove the a multivariate analogue of the above. Part D: Stretched Schur polynomials This part consists of Paper VI, where we give a combinatorial proof that certain sequences of skew Schur polynomials satisfy linear recurrences with polynomial coefficients.At the time of doctoral defence the following papers were unpublished and had a status as follows: Paper 5: Manuscript; Paper 6: Manuscript
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Possamai, Lino <1978>. "Multidimensional analysis of complex networks." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5389/1/possamai_lino_tesi.pdf.
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Complex Networks analysis turn out to be a very promising field of research, testified by many research projects and works that span different fields. Those analysis have been usually focused on characterize a single aspect of the system and a study that considers many informative axes along with a network evolve is lacking.
We propose a new multidimensional analysis that is able to inspect networks in the two most important dimensions, space and time. To achieve this goal, we studied them singularly and investigated how the variation of the constituting parameters drives changes to the network as a whole.
By focusing on space dimension, we characterized spatial alteration in terms of abstraction levels. We proposed a novel algorithm that, by applying a fuzziness function, can reconstruct networks under different level of details. We verified that statistical indicators depend strongly on the granularity with which a system is described and on the class of networks.
We keep fixed the space axes and we isolated the dynamics behind networks evolution process.
We detected new instincts that trigger social networks utilization and spread the adoption of novel communities. We formalized this enhanced social network evolution by adopting special nodes (called sirens) that, thanks to their ability to attract new links, were able to construct efficient connection patterns. We simulated the dynamics of the system by considering three well-known growth models.
Applying this framework to real and synthetic networks, we showed that the sirens, even when used for a limited time span, effectively shrink the time needed to get a network in mature state. In order to provide a concrete context of our findings, we formalized the cost of setting up such enhancement and provided the best combinations of system's parameters, such as number of sirens, time span of utilization and attractiveness.
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Possamai, Lino <1978>. "Multidimensional analysis of complex networks." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5389/.
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Complex Networks analysis turn out to be a very promising field of research, testified by many research projects and works that span different fields. Those analysis have been usually focused on characterize a single aspect of the system and a study that considers many informative axes along with a network evolve is lacking.
We propose a new multidimensional analysis that is able to inspect networks in the two most important dimensions, space and time. To achieve this goal, we studied them singularly and investigated how the variation of the constituting parameters drives changes to the network as a whole.
By focusing on space dimension, we characterized spatial alteration in terms of abstraction levels. We proposed a novel algorithm that, by applying a fuzziness function, can reconstruct networks under different level of details. We verified that statistical indicators depend strongly on the granularity with which a system is described and on the class of networks.
We keep fixed the space axes and we isolated the dynamics behind networks evolution process.
We detected new instincts that trigger social networks utilization and spread the adoption of novel communities. We formalized this enhanced social network evolution by adopting special nodes (called sirens) that, thanks to their ability to attract new links, were able to construct efficient connection patterns. We simulated the dynamics of the system by considering three well-known growth models.
Applying this framework to real and synthetic networks, we showed that the sirens, even when used for a limited time span, effectively shrink the time needed to get a network in mature state. In order to provide a concrete context of our findings, we formalized the cost of setting up such enhancement and provided the best combinations of system's parameters, such as number of sirens, time span of utilization and attractiveness.
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ARGENTO, CLAUDIO. "Complex networks: analysis and control." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2008. http://hdl.handle.net/2108/596.
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The introduction provides an overview on complex networks, trying to investigate what apparently different kinds of networks have in common. Some statistical properties are illustrated and a simulation tool for the analysis of complex networks is presented. A weighted directed random graph is used as network model. The graph contains a fixed number N of nodes and a variable number of edges: in particular, each edge is present with probability p. Some statistical properties (such as strong connection, global and local efficiency, cost, etc) are computed and their reliance on probability p is studied. Some probability distributions (such as shortest path, edge/node load) are also drawn and, by using the method of stages, the best fitting curves are computed. The way as parameters characterizing such curves change when p varies is also investigated. The general structure of the proposed fitting technique allows to model several aspects of complex networks and makes possible its use in many different fields. Finally, the tracking control problem of linear time invariant (LTI) systems when the plant and the controller belong to the same network is considered. Time delays can degrade significantly the performance of a networked control system, eventually leading to instability. The problem characterized by constant and known network delays is analytically examined, showing how to construct a plant state predictor in order to compensate the time delays between the plant and the controller, so to allow the tracking of a reference signal. Computer simulations illustrate the effectiveness of the proposed technique, also when time delays slightly vary around a mean value.
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Persson, Håkan. "On Stein Neighborhood Bases and the Nebenhülle." Thesis, Umeå University, Mathematics and Mathematical Statistics, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-31704.
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This thesis consists of three parts. The first part is a introduction to the theory of domains of holomorphy through holomorphic convexity. The second part gives a introduction to Stein neighborhood bases in Cn and presents some minor results on the Nebenhülle of a compact set in Cn. The third and final part reviews some results on the existence of Stein neighborhood bases.
Denna uppsats består av tre delar. Den första delen introducerar holomorfiområden genom teorin för konvexitet med avseende på holomorfa funktioner. Den andra delen är en introduktion till Steinomgivningsbaser i Cn och presenterar några smärre resultat rörande Nebenhüllet till en kompakt mängd i Cn. Den tredje och sista delen ger en överblick över en del resultat om existensen av Steinomgivningsbaser.
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Liu, Jiangchao. "Static analysis on numeric and structural properties of array contents." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEE046/document.
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Dans cette thèse, nous étudions l'analyse statique par interprétation abstraites de programmes manipulant des tableaux, afin d'inférer des propriétés sur les valeurs numériques et les structures de données qui y sont stockées. Les tableaux sont omniprésents dans de nombreux programmes, et les erreurs liées à leur manipulation sont difficile à éviter en pratique. De nombreux travaux de recherche ont été consacrés à la vérification de tels programmes. Les travaux existants s'intéressent plus particulièrement aux propriétés concernant les valeurs numériques stockées dans les tableaux. Toutefois, les programmes bas-niveau (comme les systèmes embarqués ou les systèmes d'exploitation temps réel) utilisent souvent des tableaux afin d'y stocker des structures de données telles que des listes, de manière à éviter d'avoir recours à l'allocation de mémoire dynamique. Dans cette thèse, nous présentons des techniques permettant de vérifier par interprétation abstraite des propriétés concernant à la fois les données numériques ainsi que les structures composites stockées dans des tableaux. Notre première contribution est une abstraction qui permet de décrire des stores à valeurs numériques et avec valeurs optionnelles (i.e., lorsqu'une variable peut soit avoir une valeur numérique, soit ne pas avoir de valeur du tout), ou bien avec valeurs ensemblistes (i.e., lorsqu'une variable est associée à un ensemble de valeurs qui peut être vide ou non). Cette abstraction peut être utilisée pour décrire des stores où certaines variables ont un type option, ou bien un type ensembliste. Elle peut aussi servir à la construction de domaines abstraits pour décrire des propriétés complexes à l'aide de variables symboliques, par exemple, pour résumer le contenu de zones dans des tableaux. Notre seconde contribution est un domaine abstrait pour la description de tableaux, qui utilise des propriétés sémantiques des valeurs contenues afin de partitionner les cellules de tableaux en groupes homogènes. Ainsi, des cellules contenant des valeurs similaires sont décrites par les mêmes prédicats abstraits. De plus, au contraire des analyses de tableaux conventionnelles, les groupes ainsi formés ne sont pas nécessairement contigüs, ce qui contribue à la généralité de l'analyse. Notre analyse peut regrouper des cellules non-congitües, lorsque celles-ci ont des propriétés similaires. Ce domaine abstrait permet de construire des analyses complètement automatiques et capables d'inférer des invariants complexes sur les tableaux. Notre troisième contribution repose sur une combinaison de cette abstraction des tableaux avec différents domaines abstraits issus de l'analyse de forme des structures de données et reposant sur la logique de séparation. Cette combinaison appelée coalescence opère localement, et relie des résumés pour des structures dynamiques à des groupes de cellules du tableau. La coalescence permet de définir de manière locale des algorithmes d'analyse statique dans le domaine combiné. Nous l'utilisons pour relier notre domaine abstrait pour tableaux et une analyse de forme générique, dont la tâche est de décrire des structures chaînées. L'analyse ainsi obtenue peut vérifier à la fois des propriétés de sûreté et des propriétés de correction fonctionnelle. De nombreux programmes bas-niveau stockent des structures dynamiques chaînées dans des tableaux afin de n'utiliser que des zones mémoire allouées statiquement. La vérification de tels programmes est difficile, puisqu'elle nécessite à la fois de raisonner sur les tableaux et sur les structures chaînées. Nous construisons une analyse statique reposant sur ces trois contributions, et permettant d'analyser avec succés de tels programmes. Nous présentons des résultats d'analyse permettant la vérification de composants de systèmes d'exploitation et pilotes de périphériquesWe study the static analysis on both numeric and structural properties of array contents in the framework of abstract interpretation. Since arrays are ubiquitous in most software systems, and software defects related to mis-uses of arrays are hard to avoid in practice, a lot of efforts have been devoted to ensuring the correctness of programs manipulating arrays. Current verification of these programs by static analysis focuses on numeric content properties. However, in some lowlevel programs (like embedded systems or real-time operating systems), arrays often contain structural data (e.g., lists) without using dynamic allocation. In this manuscript, we present a series of techniques to verify both numeric and structural properties of array contents. Our first technique is used to describe properties of numerical stores with optional values (i.e., where some variables may have no value) or sets of values (i.e., where some variables may store a possibly empty set of values). Our approach lifts numerical abstract domains based on common linear inequality into abstract domains describing stores with optional values and sets of values. This abstraction can be used in order to analyze languages with some form of option scalar type. It can also be applied to the construction of abstract domains to describe complex memory properties that introduce symbolic variables, e.g., in order to summarize unbounded memory blocks like in arrays. Our second technique is an abstract domain which utilizes semantic properties to split array cells into groups. Cells with similar properties will be packed into groups and abstracted together. Additionally, groups are not necessarily contiguous. Compared to conventional array partitioning analyses that split arrays into contiguous partitions to infer properties of sets of array cells. Our analysis can group together non-contiguous cells when they have similar properties. Our abstract domain can infer complex array invariants in a fully automatic way. The third technique is used to combine different shape domains. This combination locally ties summaries in both abstract domains and is called a coalesced abstraction. Coalescing allows to define efficient and precise static analysis algorithms in the combined domain. We utilize it to combine our array abstraction (i.e., our second technique) and a shape abstraction which captures linked structures with separation logicbased inductive predicates. The product domain can verify both safety and functional properties of programs manipulating arrays storing dynamically linked structures, such as lists. Storing dynamic structures in arrays is a programming pattern commonly used in low-level systems, so as to avoid relying on dynamic allocation. The verification of such programs is very challenging as it requires reasoning both about the array structure with numeric indexes and about the linked structures stored in the array. Combining the three techniques that we have proposed, we can build an automatic static analysis for the verification of programs manipulating arrays storing linked structures. We report on the successful verification of several operating system kernel components and drivers
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Mercat, Christian. "Analyse Complexe Discrète." Habilitation à diriger des recherches, Université Montpellier II - Sciences et Techniques du Languedoc, 2009. http://tel.archives-ouvertes.fr/tel-00439782.
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Ma contribution principale porte sur la géométrie différentielle discrète, spécialement la géométrie conforme discrète. Les champs d'application principaux que j'étudie sont l'imagerie par ordinateur et les systèmes intégrables, tant les systèmes intégrables discrets que les systèmes statistiques intégrables. Ma thèse sur le modèle d'Ising a identifié la criticité dans le modèle de taille fini comme un point où le fermion, une observable particulière, devient holomorphe pour une structure conforme discrète sous-jacente. À l'université de Melbourne, je me suis intéressé avec Paul Pearce aux modèles ADE qui sont une généralisation du modèle d'Ising, dans le but (inachevé mais en bonne voie) d'y identifier un analogue discret de l'algèbre des opérateurs vertex (les conditions de bord conformes et intégrables) et des blocs conformes, en particulier dans l'espoir de comprendre la criticité comme une compatibilité à l'holomorphie discrète. À l'université technique de Berlin, avec Alexander Bobenko et son équipe, j'ai compris la nature intégrable du modèle associé à l'holomorphie discrète (linéaire et quadratique) et utilisé les outils très puissants de cette théorie (isomonodromie, transformations de Darboux-Bäcklund, finite-gap) pour mettre à jour la position centrale de l'analyse complexe discrète dans la hiérarchie des systèmes intégrables discrets. À Montpellier, dans l'équipe Arith dirigée par Valérie Berthé, j'ai appliqué cette théorie dans le cadre de la géométrie différentielle discrète, particulièrement dans le cadre voxellique de la géométrie digitale.
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Kahloul, Senda. "Analyse structurale et fonctionnelle de la sous-unité SKP1 du complexe SCF (Skp1-Cullin-Fbox) chez le riz (Oryza sativa)." Thesis, Clermont-Ferrand 2, 2012. http://www.theses.fr/2012CLF22326/document.
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Chez les eucaryotes, la voie de protéolyse Ub/ protéasome 26S est responsable de la dégradation sélective de la plupart des protéines intracellulaires. Cette dégradation par le protéasome 26S est initiée par une polyubiquitination de la protéine réalisée grâce à l’action d’une cascade enzymatique impliquant 3 types d'enzymes nommées « ubiquitin-activating enzyme » (E1), « ubiquitin-conjugating enzyme » (E2) et « ubiquitin-protein ligase » (E3). Il existe différentes classes d’ubiquitines ligases (E3), parmi lesquelles la plus connue est le complexe SCF (Skp1-Cullin-F-box). La protéine SKP1 fixe à la fois la Culline et la F-box qui va reconnaitre spécifiquement la protéine cible. Contrairement aux protistes, les champignons et certains vertébrés qui possèdent un unique gène SKP1 fonctionnel, de nombreux animaux et espèces de plantes présentent plusieurs SKP1 homologues. Vingt et un et trente deux gènes SKP1 ont été décrits respectivement chez Arabidopsis thaliana et Oryza sativa. En dépit de l’importance du complexe SCF, chez le riz, peu de travaux décrivent les interactions entre les dizaines de protéines « SKP1-like » et les centaines de protéines F-box. Dans un premier temps, nous avons collecté et analysé les séquences de 288 gènes « SKP1-like » appartenant à 17 espèces, dont la mousse Physcomitrella patens, cinq monocotylédones et 11 eudicotylédones. Les analyses structurales et phylogénétiques de ces gènes indiquent qu’ils peuvent être divisés en différentes sous-familles. Nos analyses ont montré qu’OSK1 et OSK20 chez le riz constituent une classe de gènes SKP1 à intron unique conservé. Dans un deuxième temps, nous avons étudié le profil d’expression des gènes « SKP1-like » chez le riz. Notre investigation sur le nombre d’EST a montré que les gènes OSK1 et OSK20 sont les plus largement représentés dans les bases de données EST publiques. La méta-analyse de l’expression des gènes « SKP1-like » chez le riz, indique que les gènes OSK présentent des profils d'expression hétérogènes selon les tissus et les conditions physiologiques. Les résultats des intearctions protéine-protéine en double hybride ont révélé que les protéines OSK présentent différentes capacités d’interactions avec les protéines F-box. Cependant, OSK1 et OSK20 semblent interagir avec la plupart des protéines F-box testées. Les études de localisation subcellulaire ont indiqué que OSK1 et OSK20 sont des protéines nucléaires et cytosoliques. En se basant sur les divers résultats obtenus dans ce travail, nous pouvons suggérer que chez le riz, les gènes OSK1 et OSK20 sont fonctionnellement équivalents aux gènes ASK1 et ASK2 chez Arabidopsis thaliana. Nous pouvons également proposer les équivalents de ces gènes chez les autres espèces végétales dont le génome a été séquencéIn eukaryotes, the ubiquitin Ub/26S proteasome pathway is responsible for the selective degradation of most intracellular proteins. This cellular process is initiated by protein polyubiquitination mediated by a three-step cascade involving: an ubiquitin-activating enzyme (E1), an ubiquitin-conjugating enzyme (E2) and an ubiquitin-protein ligase (E3). The E3 ubiquitin ligases contain several classes, among which the best-known are Skp1-Cullin-F-box (SCF) complexes. The SKP1 protein binds both Cullin and F-box which recognizes specifically the target proteins. Whereas protists, fungi and some vertebrates have a single functional SKP1 gene, many animal and plant species possess multiple SKP1 homologues. Twenty one and thirty-two SKP1-related genes have been described respectively in the Arabidopsis and Oryza sativa genome. Despite the importance of the SCF complex, there have been a few reports of systematic surveys of interactions between the dozens of SKP1-like proteins and the hundreds of F-box proteins in rice. In a first step, we retrieved and analyzed 288 SKP1-like genes belonging to 17 species including the moss Physcomitrella patens, five monocots and 11 eudicots. Structural and phylogenetic analysis of rice OSK genes and other plant SKP1-like genes have indicated that the different members of the plant SKP1 can be split into different subfamily. Our analyses indicated that OSK1 and OSK20 belong to a class of SKP1 genes that contain one intron at a conserved position. In a second step, we studied expression profiles of the rice Skp1-like genes. Our EST survey indicated that OSK1 and OSK20 are the most widely represented genes in public EST databases. Meta-analysis of the expression of rice SKP1-like genes indicated that OSK genes exhibit an expression profile that was heterogeneous in terms of tissues, conditions and overall intensity. Yeast two-hybrid results revealed that OSK proteins display a differing ability to interact with F-box proteins. However, OSK1 and OSK20 seemed to interact with most F-box proteins tested. Subcellular localization studies indicated that OSK1 and OSK20 are nuclear and cytosolic proteins. Based on the results obtained in this study, we can suggest that rice OSK1 and OSK20 are likely to have similar functions as do the Arabidopsis ASK1 and ASK2 genes. Similarly, we suggest a list of functional equivalent in the other sequenced plant genomes
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da, Silva Dilma Menezes. "A framework for building complex systems." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/9229.
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McGoverin, Cushla Maree, and n/a. "Raman spectroscopy of complex mixtures." University of Otago. Department of Chemistry, 2008. http://adt.otago.ac.nz./public/adt-NZDU20081103.112612.
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This thesis presents several Raman spectroscopic studies of bovine milk-derived products (skim and whole milk powder, anhydrous milk fat, processed cheese and soy cheese made from milk protein). Raman spectroscopy, unlike infrared spectroscopy (both mid- and near-infrared), has not been widely used as an analytical tool within the dairy industry. The purpose of this project was to assess the utility of Raman spectroscopy in several dairy industry relevant problems. FT-Raman spectroscopy coupled with partial least squares (PLS) reliably predicted the concentration of fat and protein within whole milk and protein within skim milk powders as evidenced by ratios of prediction to deviation in excess of three. It was shown that sample geometry did not significantly affect the calculated predictive models, thereby allowing the simplest, quickest method of sample presentation to be utilised without harming quantification model efficacy.
The fat fraction of milk was further investigated, and it was shown that Raman spectra collected from anhydrous milk fat samples were a good basis for solid fat content (SFC) determination. Such spectra were collected when the samples were held at 40 �C, pretreated by baselining and area normalisation, and analysed using PLS with modified jack-knifing (PLS1-JK). Triacylglycerol class concentrations were also well predicted by PLS1-JK models developed from Raman spectroscopic data. Resonance enhancement of β-carotene within fat was shown to have little effect on the reliability of the optimal prediction model when compared to SFC Raman quantification.
Raman microscopic mapping for heterogeneity description of processed cheese and soy cheese mimics was examined. The FT-Raman milk powder constituents study had shown fat and protein Raman spectra within complex dairy mixtures could be distinguished, hence this utility was applied to mapping of cheese systems. Univariate, principal components analysis and multivariate curve resolution methods of analyses were compared; as expected the more complex samples required multivariate methods of analyses. Raman microscopic mapping was not a time efficient method in comparison to the standard method of confocal laser scanning microscopy. However, Raman spectroscopic mapping is a more universal technique which allowed the presence of an unexpected localised constituent within the soy cheese mimics to be observed. It was proposed that this constituent was a crystalline form of a short saturated fatty acid.
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Bui, Quang Vu. "Pretopology and Topic Modeling for Complex Systems Analysis : Application on Document Classification and Complex Network Analysis." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEP034/document.
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Les travaux de cette thèse présentent le développement d'algorithmes de classification de documents d'une part, ou d'analyse de réseaux complexes d'autre part, en s'appuyant sur la prétopologie, une théorie qui modélise le concept de proximité. Le premier travail développe un cadre pour la classification de documents en combinant une approche de topicmodeling et la prétopologie. Notre contribution propose d'utiliser des distributions de sujets extraites à partir d'un traitement topic-modeling comme entrées pour des méthodes de classification. Dans cette approche, nous avons étudié deux aspects : déterminer une distance adaptée entre documents en étudiant la pertinence des mesures probabilistes et des mesures vectorielles, et effet réaliser des regroupements selon plusieurs critères en utilisant une pseudo-distance définie à partir de la prétopologie. Le deuxième travail introduit un cadre général de modélisation des Réseaux Complexes en développant une reformulation de la prétopologie stochastique, il propose également un modèle prétopologique de cascade d'informations comme modèle général de diffusion. De plus, nous avons proposé un modèle agent, Textual-ABM, pour analyser des réseaux complexes dynamiques associés à des informations textuelles en utilisant un modèle auteur-sujet et nous avons introduit le Textual-Homo-IC, un modèle de cascade indépendant de la ressemblance, dans lequel l'homophilie est fondée sur du contenu textuel obtenu par un topic-modelThe work of this thesis presents the development of algorithms for document classification on the one hand, or complex network analysis on the other hand, based on pretopology, a theory that models the concept of proximity. The first work develops a framework for document clustering by combining Topic Modeling and Pretopology. Our contribution proposes using topic distributions extracted from topic modeling treatment as input for classification methods. In this approach, we investigated two aspects: determine an appropriate distance between documents by studying the relevance of Probabilistic-Based and Vector-Based Measurements and effect groupings according to several criteria using a pseudo-distance defined from pretopology. The second work introduces a general framework for modeling Complex Networks by developing a reformulation of stochastic pretopology and proposes Pretopology Cascade Model as a general model for information diffusion. In addition, we proposed an agent-based model, Textual-ABM, to analyze complex dynamic networks associated with textual information using author-topic model and introduced Textual-Homo-IC, an independent cascade model of the resemblance, in which homophily is measured based on textual content obtained by utilizing Topic Modeling
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Silva, Jonathan Cardoso. "Optimisation-based methodologies for complex data analysis." Thesis, King's College London (University of London), 2018. https://kclpure.kcl.ac.uk/portal/en/theses/optimisationbased-methodologies-for-complex-data-analysis(7ef64e5c-f9ef-44e7-804a-a21ec25dd007).html.
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Networks are a natural representation of data collected across many disciplines. The complex relationships between entities studied in these fields, whether it be people, computers or molecules, cannot be fully characterised individually but are, instead, better described by computational models as a function of their overall interactions. This thesis focuses on the development of such models to detect communities and to predict outcome variables in real networks using mathematical programming, a transparent, flexible and customisable modelling paradigm. First, the temporal evolution of groups in complex social networks is explored. Various methods detect groups in dynamic networks either by aggregating all temporal contact information into a single network or by looking at snapshots of time independently. In this work, a more robust approach is employed where, at each time step, both the current and previous modular structures of a network are considered. A mixed integer non-linear programming (MINLP) model is proposed to capture more stable patterns of change and was shown to match the ground truth of networks. Next, the development of Quantitative Structure-Activity Relationship models (QSAR) is addressed. These regression models are vastly used in drug discovery and aim to predict biological activity from the attributes of molecules. In this work, algorithms are proposed to divide the compounds in sub-groups either by their molecular features or from modules that naturally arise when representing this data as a network. Suitable equations that predict biological activity are then identified for each group by a mathematical programming model. These algorithms create predictive, customisable and interpretable QSAR sub-models, which can later be used for virtual screening, SAR studies or lead optimisation of drug candidates. Overall, this thesis proposes computational models to optimisation problems in regression and network analysis. The proposed methods produce transparent and interpretable solutions towards a better understanding of the dynamics of social systems and have the potential to assist in the endeavours of drug discovery.
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Buchet, Mickaël. "Topological inference from measures." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112367/document.
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La quantité de données disponibles n'a jamais été aussi grande. Se poser les bonnes questions, c'est-à-dire des questions qui soient à la fois pertinentes et dont la réponse est accessible est difficile. L'analyse topologique de données tente de contourner le problème en ne posant pas une question trop précise mais en recherchant une structure sous-jacente aux données. Une telle structure est intéressante en soi mais elle peut également guider le questionnement de l'analyste et le diriger vers des questions pertinentes. Un des outils les plus utilisés dans ce domaine est l'homologie persistante. Analysant les données à toutes les échelles simultanément, la persistance permet d'éviter le choix d'une échelle particulière. De plus, ses propriétés de stabilité fournissent une manière naturelle pour passer de données discrètes à des objets continus. Cependant, l'homologie persistante se heurte à deux obstacles. Sa construction se heurte généralement à une trop large taille des structures de données pour le travail en grandes dimensions et sa robustesse ne s'étend pas au bruit aberrant, c'est-à-dire à la présence de points non corrélés avec la structure sous-jacente.Dans cette thèse, je pars de ces deux constatations et m'applique tout d'abord à rendre le calcul de l'homologie persistante robuste au bruit aberrant par l'utilisation de la distance à la mesure. Utilisant une approximation du calcul de l'homologie persistante pour la distance à la mesure, je fournis un algorithme complet permettant d'utiliser l'homologie persistante pour l'analyse topologique de données de petite dimension intrinsèque mais pouvant être plongées dans des espaces de grande dimension. Précédemment, l'homologie persistante a également été utilisée pour analyser des champs scalaires. Ici encore, le problème du bruit aberrant limitait son utilisation et je propose une méthode dérivée de l'utilisation de la distance à la mesure afin d'obtenir une robustesse au bruit aberrant. Cela passe par l'introduction de nouvelles conditions de bruit et l'utilisation d'un nouvel opérateur de régression. Ces deux objets font l'objet d'une étude spécifique. Le travail réalisé au cours de cette thèse permet maintenant d'utiliser l'homologie persistante dans des cas d'applications réelles en grandes dimensions, que ce soit pour l'inférence topologique ou l'analyse de champs scalairesMassive amounts of data are now available for study. Asking questions that are both relevant and possible to answer is a difficult task. One can look for something different than the answer to a precise question. Topological data analysis looks for structure in point cloud data, which can be informative by itself but can also provide directions for further questioning. A common challenge faced in this area is the choice of the right scale at which to process the data.One widely used tool in this domain is persistent homology. By processing the data at all scales, it does not rely on a particular choice of scale. Moreover, its stability properties provide a natural way to go from discrete data to an underlying continuous structure. Finally, it can be combined with other tools, like the distance to a measure, which allows to handle noise that are unbounded. The main caveat of this approach is its high complexity.In this thesis, we will introduce topological data analysis and persistent homology, then show how to use approximation to reduce the computational complexity. We provide an approximation scheme to the distance to a measure and a sparsifying method of weighted Vietoris-Rips complexes in order to approximate persistence diagrams with practical complexity. We detail the specific properties of these constructions.Persistent homology was previously shown to be of use for scalar field analysis. We provide a way to combine it with the distance to a measure in order to handle a wider class of noise, especially data with unbounded errors. Finally, we discuss interesting opportunities opened by these results to study data where parts are missing or erroneous
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Lashgari, Iman. "Global stability analysis of complex fluids." Licentiate thesis, KTH, Mekanik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-139405.
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The main focus of this work is on the non-Newtonian effects on the inertial instabilities in shear flows. Both inelastic (Carreau) and elastic models (Oldroyd-B and FENE-P) have been employed to examine the main features of the non-Newtonian fluids; shear-thinning, shear-thickening and elasticity. Several classical configurations have been considered; flow past a circular cylinder, in a lid-driven cavity and in a channel. We have used a wide range of tools for linear stability analysis, modal, non-modal, energy and sensitivity analysis, to determine the instability mechanisms of the non-Newtonian flows and compare them with those of the Newtonian flows. Direct numerical simulations have been also used to prove the results obtained by the linear stability analysis. Significant modifications/alterations in the instability of the different flows have been observed under the action of the non-Newtonian effects. In general, shear-thinning/shear-thickening effects destabilize/stabilize the flow around the cylinder and in a lid driven cavity. Viscoelastic effects both stabilize and destabilize the channel flow depending on the ratio between the viscoelastic and flow time scales. The instability mechanism is just slightly modified in the cylinder flow whereas new instability mechanisms arise in the lid-driven cavity flow. We observe that the non-Newtonian effect can alter the inertial flow at both baseflow and perturbation level (e.g. Carreau fluid past a cylinder or in a lid driven cavity) or it may just affect the perturbations (e.g. Oldroyd-B fluid in channel). In all the flow cases studied, the modifications in the instability dynamics are shown to be strongly connected to the contribution of the different terms in the perturbation kinetic energy budget.QC 20140113
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Belinschi, Serban Teodor. "Complex analysis methods in noncommutative probability." [Bloomington, Ind.] : Indiana University, 2005. http://wwwlib.umi.com/dissertations/fullcit/3182615.
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Thesis (Ph.D.)--Indiana University, Dept. of Mathematics, 2005.Source: Dissertation Abstracts International, Volume: 66-07, Section: B, page: 3738. Adviser: Hari Bercovici. Title from dissertation home page (viewed Oct. 5, 2006).