Thèses : « Tree distance »

1

Rhodes, Benjamin Robert. « On the Discrete Number of Tree Graphs ». Thesis, Virginia Tech, 2020. http://hdl.handle.net/10919/98536.

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We study a generalization of the problem of finding bounds on the number of discrete chains, which itself is a generalization of the Erdős unit distance problem. Given a set of points in Euclidean space and a tree graph consisting of a much smaller number of vertices, we study the maximum possible number of tree graphs which can be represented by a prescribed tree graph. We derive an algorithm for finding tight bounds for this family of problems up to chain bound discrepancy, and give upper and lower bounds in special cases.
Master of Science
We study a generalization of the problem of finding bounds on the number of discrete chains, which itself is a generalization of the Erdős unit distance problem, a famous mathematics problem named after mathematician Paul Erdős. Given a set of points, and a tree graph of a much smaller amount of vertices, we study the maximum possible number of tree graphs which can be represented by a prescribed tree graph. We derive an algorithm for finding tight bounds for this family of problems up to chain bound discrepancy, and give upper and lower bounds in special cases.

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Mou, Chengcheng. « A Comparative Study of Dual-tree Algorithms for Computing Spatial Distance Histogram ». Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5836.

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Particle simulation has become an important research technique in many scientific and engineering fields in latest years. However, these simulations will generate countless data, and database they required would therefore deal with very challenging tasks in terms of data management, storage, and query processing. The two-body correlation function (2-BCFs), a statistical learning measurement to evaluate the datasets, has been mainly utilized to measure the spatial distance histogram (SDH). By using a straightforward method, the process of SDH query takes quadratic time. Recently, a novel algorithm has been proposed to compute the SDH based on the concept of density map (DM), and it reduces the running time to ϴ(N(3/2)) for two-dimensional data and ϴ (N(5/3) ) for three-dimensional data, respectively. In the DM-SDH algorithm, there are two types of DMs that can be plugged in for computation: Quad-tree (Oct-tree for three-dimensional data) and k-d tree data structure. In this thesis paper, by using the geometric method, we prove the unre- solvable ratios on the k-d tree. Further, we analyze and compare the difference in the performance in each potential case generated by these DM-SDH algorithms. Experimental results confirm our analysis and show that the k-d tree structure has better performance in terms of time complexity in all cases. However, our qualitative analysis shows that the Quad-tree (Oct-tree) has an advantage over the k-d tree on aspect of space complexity.

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García-González, Ignacio. « Comparison Of Different Distance Measures For Cluster Analysis Of Tree-Ring Series ». Tree-Ring Society, 2008. http://hdl.handle.net/10150/622565.

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Sixty individual ring-width series of oak (Quercus robur L.) from six sites in the northwestern Iberian Peninsula, ranging from 50 to 120 years, were grouped using hierarchical cluster analysis with different types of distance measures. Euclidean distances as well as other linkage distances based on statistics used to crossdate tree-ring series (Gleichläufigkeit and coefficient of correlation with its corresponding t-value) were compared. In addition, a new distance measure based on a corrected inversion of the Student’s t is proposed in the present paper, which takes into consideration the number of years used for series comparison. The Euclidean distances, commonly used in ecological analyses, inefficiently identified homogeneous units of trees based on their ring-width patterns. Among crossdating statistics, the correlation coefficient was more effective than Gleichläufigkeit, but the most satisfactory results were obtained when 1/t was used as distance measure. Finally, these methods of cluster analysis have been implemented into a computer program for future use of the dendrochronological community.

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Sharma, Luetel Sadhana. « Performance analysis of a binary-tree-based algorithm for computing Spatial Distance Histograms ». [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0003136.

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5

Billingham, Martin Robert. « Genetic structure, localised adaptation and optimal outcrossing distance in two neotropical tree species ». Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301795.

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Comtet, Jean. « Passive phloem loading and long-distance transport in a synthetic tree-on-a-chip ». Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/101330.

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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 45-46).
According to the Munch mechanism, vascular plants rely on osmotic pressure gradients to export sugars from regions of synthesis (mature leaves) to sugar sinks (roots, fruits). A crucial step in this process is the loading of sugars from photosynthetic cells to the export conduit (the phloem). In this thesis, we developed a synthetic microfluidic osmotic pump mimicking the mechanism of passive phloem loading, where sugars are transported by diffusion from a sugar reservoir to the phloem. This design allows the development of steady flow over several hours. We show that in our system, phloem concentration is set by a relative balance between loading by diffusion from the source and export by convection through the phloem, via a single nondimensional system-scale Peclet number that we call the flushing number. For large flushing numbers, export is limited by diffusion from the source, and flow rates scale weakly with transport resistance. For low flushing numbers, export is limited by convection through the phloem and phloem concentration is close to that of the source, leading to efficient export of water and sugars. In plants, passive phloem loading is used predominantly by trees. We show that the hydrostatic pressures developed in our synthetic system can reach up to ten bars and are thus compatible with the pressures expected to drive long-distance transport in large trees. Moreover, we show that the regime of efficient export in passive loaders is more accessible to plants with large transport resistances, providing a rational for the use of the passive loading mechanism by most tree species.
by Jean Comtet.
S.M.

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Mori, Tomoya. « Methods for Analyzing Tree-Structured Data and their Applications to Computational Biology ». 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/202741.

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Elias, Isaac. « Computational problems in evolution : Multiple alignment, genome rearrangements, and tree reconstruction ». Doctoral thesis, KTH, Numerical Analysis and Computer Science, NADA, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4170.

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Reconstructing the evolutionary history of a set of species is a fundamental problem in biology. This thesis concerns computational problems that arise in different settings and stages of phylogenetic tree reconstruction, but also in other contexts. The contributions include:

• A new distance-based tree reconstruction method with optimal reconstruction radius and optimal runtime complexity. Included in the result is a greatly simplified proof that the NJ algorithm also has optimal reconstruction radius. (co-author Jens Lagergren)

• NP-hardness results for the most common variations of Multiple Alignment. In particular, it is shown that SP-score, Star Alignment, and Tree Alignment, are NP hard for all metric symbol distances over all binary or larger alphabets.

• A 1.375-approximation algorithm for Sorting By Transpositions (SBT). SBT is the problem of sorting a permutation using as few block-transpositions as possible. The complexity of this problem is still open and it was a ten-year-old open problem to improve the best known 1.5-approximation ratio. The 1.375-approximation algorithm is based on a new upper bound on the diameter of 3-permutations. Moreover, a new lower bound on the transposition diameter of the symmetric group is presented and the exact transposition diameter of simple permutations is determined. (co-author Tzvika Hartman)

• Approximation, fixed-parameter tractable, and fast heuristic algorithms for two variants of the Ancestral Maximum Likelihood (AML) problem: when the phylogenetic tree is known and when it is unknown. AML is the problem of reconstructing the most likely genetic sequences of extinct ancestors along with the most likely mutation probabilities on the edges, given the phylogenetic tree and sequences at the leafs. (co-author Tamir Tuller)

• An algorithm for computing the number of mutational events between aligned DNA sequences which is several hundred times faster than the famous Phylip packages. Since pairwise distance estimation is a bottleneck in distance-based phylogeny reconstruction, the new algorithm improves the overall running time of many distancebased methods by a factor of several hundred. (co-author Jens Lagergren)

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Emprin, Gustave. « Une topologie pour les arbres labellés, application aux arbres aléatoires s-compacts ». Thesis, Paris Est, 2019. http://www.theses.fr/2019PESC1032.

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Dans cette thèse, nous développons un nouvel espace pour l'étude des espaces métriques labellés et mesurés, dans l'optique de décrire des arbres généalogiques dont la racine est infiniment ancienne. Dans ces arbres, le temps est représenté par une fonction label qui est 1-Lipschitz. On appelle espace métrique labellé S-compact et mesuré tout espace métrique E équipé d'une mesure nu et d'une fonction-label 1-Lipschitz de E dans R, avec la condition supplémentaire que chaque tranche (l'ensemble des points de E dont le label appartient à un compact de R) doit être compact et avoir mesure finie. On note XS l'ensemble des espaces métriques labellés mesurés S-compacts, considérés à isométries près. Sur XS, on définit une distance dLGHP de type Gromov qui compare les tranches. Il s'ensuit une étude de l'espace (XS, dLGHP), dont on montre qu'il est polonais. De cette étude, on déduit les propriétés de l'ensemble T des éléments de XS qui sont des arbres continus dont les labels décroissent à vitesse 1 quand on se déplace vers la ``racine'' (qui peut être infiniment loin). Chaque valeur possible de la fonction label représente une génération de l'arbre généalogique. On montre que (T, dLGHP) est aussi polonais. On définit ensuite quelques opérations mesurables sur T, dont le recollement aléatoire d'une forêt sur un arbre.On utilise enfin cette dernière opération pour construire un arbre aléatoire qui est un bon candidat pour généraliser l'arbre brownien conditionné par son temps local (construction due à Aldous)
In this thesis, we develop a new space for the study of measured labelled metric spaces, ultimately designed to represent genealogical trees with a root at generation minus infinity. The time in the genealogical tree is represented by a 1-Lipschitz label function. We define the notion of S-compact measured labelled metric space, that is a metric space E equipped with a measure nu and a 1-Lipschitz label function from E to R, with the additional condition that each slice (the set of points with labels in a compact of R) must be compact and have finite measure. On the space XS of measured labelled metric spaces (up to isometry), we define a distance dLGHP by comparing the slices and study the resulting metric space, which we find to be Polish.We proceed with the study of the set T of all elements of XS that are real tree in which the label function decreases at rate 1 when we go toward the root" (which can be infinitely far). Each possible value of the label function corresponds to a generation in the genealogical tree. We prove that (T, dLGHP) is Polish as well. We define a number of measurable operation on T, including a way to randomly graft a forest on a tree. We use this operation to build a particular random tree generalizing Aldous' Brownian motion conditioned on its local time

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Tsunamoto, Yoshihiro. « Seed dispersal dynamics of a fleshy-fruited tree Swida controversa by various frugivorous animals ». Kyoto University, 2018. http://hdl.handle.net/2433/235096.

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BERNARDINI, GIULIA. « COMBINATORIAL METHODS FOR BIOLOGICAL DATA ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2021. http://hdl.handle.net/10281/305220.

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Lo scopo di questa tesi è di elaborare e analizzare metodi rigorosi dal punto di vista matematico per l’analisi di due tipi di dati biologici: dati relativi a pan-genomi e filogenesi. Con il termine “pan-genoma” si indica, in generale, un insieme di sequenze genomiche strettamente correlate (tipicamente appartenenti a individui della stessa specie) che si vogliano utilizzare congiuntamente come sequenze di riferimento per un’intera popolazione. Una filogenesi, invece, rappresenta le relazioni evolutive in un gruppo di entità, che siano esseri viventi, geni, lingue naturali, manoscritti antichi o cellule tumorali. Con l’eccezione di uno dei risultati presentati in questa tesi, relativo all’analisi di filogenesi tumorali, il taglio della dissertazione è prevalentemente teorico: lo scopo è studiare gli aspetti combinatori dei problemi affrontati, più che fornire soluzioni efficaci in pratica. Una conoscenza approfondita degli aspetti teorici di un problema, del resto, permette un'analisi matematicamente rigorosa delle soluzioni già esistenti, individuandone i punti deboli e quelli di forza, fornendo preziosi dettagli sul loro funzionamento e aiutando a decidere quali problemi vadano ulteriormente investigati. Oltretutto, è spesso il caso che nuovi risultati teorici (algoritmi, strutture dati o riduzioni ad altri problemi più noti) si possano direttamente applicare o adattare come soluzione ad un problema pratico, o come minimo servano ad ispirare lo sviluppo di nuovi metodi efficaci in pratica. La prima parte della tesi è dedicata a nuovi metodi per eseguire delle operazioni fondamentali su un testo elastico-degenerato, un oggetto computazionale che codifica in maniera compatta un insieme di testi simili tra loro, come, ad esempio, un pan-genoma. Nello specifico, si affrontano il problema di cercare una sequenza di lettere in un testo elastico-degenerato, sia in maniera esatta che tollerando un numero prefissato di errori, e quello di confrontare due testi degenerati. Nella seconda parte si considerano sia filogenesi tumorali, che ricostruiscono per l'appunto l'evoluzione di un tumore, sia filogenesi "classiche", che rappresentano, ad esempio, la storia evolutiva delle specie viventi. In particolare, si presentano nuove tecniche per confrontare due o più filogenesi tumorali, necessarie per valutare i risultati di diversi metodi che ricostruiscono le filogenesi stesse, e una nuova e più efficiente soluzione a un problema di lunga data relativo a filogenesi "classiche", consistente nel determinare se sia possibile sistemare, in presenza di dati mancanti, un insieme di specie in un albero filogenetico che abbia determinate proprietà.
The main goal of this thesis is to develop new algorithmic frameworks to deal with (i) a convenient representation of a set of similar genomes and (ii) phylogenetic data, with particular attention to the increasingly accurate tumor phylogenies. A “pan-genome” is, in general, any collection of genomic sequences to be analyzed jointly or to be used as a reference for a population. A phylogeny, in turn, is meant to describe the evolutionary relationships among a group of items, be they species of living beings, genes, natural languages, ancient manuscripts or cancer cells. With the exception of one of the results included in this thesis, related to the analysis of tumor phylogenies, the focus of the whole work is mainly theoretical, the intent being to lay firm algorithmic foundations for the problems by investigating their combinatorial aspects, rather than to provide practical tools for attacking them. Deep theoretical insights on the problems allow a rigorous analysis of existing methods, identifying their strong and weak points, providing details on how they perform and helping to decide which problems need to be further addressed. In addition, it is often the case where new theoretical results (algorithms, data structures and reductions to other well-studied problems) can either be directly applied or adapted to fit the model of a practical problem, or at least they serve as inspiration for developing new practical tools. The first part of this thesis is devoted to methods for handling an elastic-degenerate text, a computational object that compactly encodes a collection of similar texts, like a pan-genome. Specifically, we attack the problem of matching a sequence in an elastic-degenerate text, both exactly and allowing a certain amount of errors, and the problem of comparing two degenerate texts. In the second part we consider both tumor phylogenies, describing the evolution of a tumor, and “classical” phylogenies, representing, for instance, the evolutionary history of the living beings. In particular, we present new techniques to compare two or more tumor phylogenies, needed to evaluate the results of different inference methods, and we give a new, efficient solution to a longstanding problem on “classical” phylogenies: to decide whether, in the presence of missing data, it is possible to arrange a set of species in a phylogenetic tree that enjoys specific properties.

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Howell, Gareth. « Normalised distance function considered over the partition of the unit interval generated by the points of the Farey tree ». Thesis, Cardiff University, 2010. http://orca.cf.ac.uk/55096/.

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Hao, Guangyou. « Water Relations and Carbon Economy of Hemiepiphytic and Non-hemiepiphytic Ficus Tree Species in Southwest China ». Scholarly Repository, 2010. http://scholarlyrepository.miami.edu/oa_dissertations/385.

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Hemiepiphytes are important components of tropical forests and are attractive to scientists due to their unique epiphytic growth habit during some period of their life cycle. Unique characteristics in plant water relations and carbon economy have been found in hemiepiphytic plants; however, to further understand this group of species on an evolutionary basis it is necessary to carry out comparative studies between hemiepiphytes and their close relatives. In this dissertation I conduced a comparative study in a suite of functional traits related to plant water relations and photosynthesis between hemiepiphytic and non-hemiepiphytic tree species from a single genus-Ficus. Great differentiation in functional traits has been found between species of the two growth forms both during juvenile and adult stages. Seedlings of hemiepiphytic Ficus species (H) had significantly lower xylem hydraulic conductivity, stomatal conductance, net light saturated CO2 assimilation, and higher water use efficiency than congeneric non-hemiepiphytic species (NH), which are adaptive to a drought-prone epiphytic growth conditions under natural conditions. The conservative water use adaptation in H species is likely crucial to the drought tolerance and survival in the forest canopy but is related to much lower growth rates than NH species. Species of the two growth forms both showed relatively large plasticity in responding to variation in light level as in typical light-demanding species. Surprisingly, the NH species showed characteristics related to higher light demand than H species, which is opposite from the prediction that H species are more light-demanding than NH species. Thus, although commonly accepted, it is likely that light was not the selective pressure for the evolution of hemiepiphytism in Ficus. Using adult trees grown in a common garden, I found that H species showed characteristics of more conservative water use even after they established connections to the soil. Moreover, H species showed significantly different traits in photochemistry compared to NH species due to hydraulic-photosynthetic coordination. The evolution of an epiphytic growth habit during the juvenile stage of a life cycle in the hemiepiphytic Ficus species thus involved changes in a suite of functional traits that persist during their terrestrial growth stages.

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Baseski, Emre. « Context-sensitive Matching Of Two Shapes ». Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607353/index.pdf.

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The similarity between two shapes is typically calculated by measuring how well the properties and the spatial organization of the primitives forming the shapes agree. But, when this calculations are done independent from the context, i.e. the whole set of shapes in the experiments, a priori significance to the primitives is assigned, which may cause problematic similarity measures. A possible way of using context information in similarity measure between shape A and shape B is using the category information of shape B in calculations. In this study, shapes are represented as depth-1 shape trees and the dissimilarity between two shapes is computed by using an approximate tree matching algorithm. The category information is created as the union of shape trees that are in the same category and this information guides the matching process between a query shape and a shape whose category is known.

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BALDASSARRE, ALESSIO. « Advances On The Analysis Of Ordinal Data Expressed As Rankings And Paired Comparisons : Distance-based Approaches, New Probabilistic Models, And Tree-based Applications ». Doctoral thesis, Università degli Studi di Cagliari, 2022. http://hdl.handle.net/11584/333409.

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This thesis represents an original contribution to knowledge on ordinal data, which constitutes the leitmotif of the entire research product. Specifically, a short review of preference data presents the leading distance and correlations measures with a focus on two weighted measures (i.e., distance and correlation). A simulation study investigates the effect of introducing positional weights when preferences are analyzed through distance-based approaches. The weighted correlation coefficient is then used as cost function within an evolutionary algorithm for finding the consensus ranking. Then, we will focus on analyzing ordinal data through probabilistic approaches, presenting a new tree-based model, the Bradley-Terry Regression Trunk model (BTRT). Again, a simulation study is conducted to evaluate the performance of the pruning procedure implemented in the new algorithm. This model is applied on two different datasets: the first is composed of self-reported data by students from the University of Cagliari; the second derives from well-known databases and contains financial information about tax revenues by central governments worldwide and their socio-economic characteristics. The BTRT model is applied to the first dataset to partition students based on their preference rankings about the attributes they expect from an ideal professor. For the second dataset, the goal is to apply the BTRT model for partitioning countries based on the size of their tax revenues and how their socio-economic characteristics influence these revenues. The BTRT model furnishes an easy-to-read partition in the form of a small regression tree, called trunk, able to capture the interactions between covariates that cause the most significant decrease in model deviance. Hence, it finds the best interactions between covariates by simultaneously considering their main effects. Finally, the last chapter shows an advance for the BTRT model by following the Mallows specification of the Bradley-Terry model. The Mallows specification works on rankings instead of paired comparisons. It assumes independence across the ranked objects so that the probability of observing a specific ranking is proportional to the product of the estimated worth parameters for each object. The BTRT model with the Mallows specification is applied to the financial dataset to discover the causal effect between government expenditure and tax revenues.

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Riveros, Jaeger Cristian. « Repairing strings and trees ». Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:012d384f-d1d0-471b-ae6e-bbf337892680.

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What do you do if a computational object fails a specification? An obvious approach is to repair it, namely, to modify the object minimally to get something that satisfies the constraints. In this thesis we study foundational problems of repairing regular specifications over strings and trees. Given two regular specifications R and T we aim to understand how difficult it is to transform an object satisfying R into an object satisfying T. The setting is motivated by considering R to be a restriction -- a constraint that the input object is guaranteed to satisfy -- while T is a target -- a constraint that we want to enforce. We first study which pairs of restriction and target specifications can be repaired with a ``small'' numbers of changes. We formalize this as the bounded repair problem -- to determine whether one can repair each object satisfying R into T with a uniform number of edits. We provide effective characterizations of the bounded repair problem for regular specifications over strings and trees. These characterizations are based on a good understanding of the cyclic behaviour of finite automata. By exploiting these characterizations, we give optimal algorithms to decide whether two specifications are bounded repairable or not. We also consider the impact of limitations on the editing process -- what happens when we require the repair to be done sequentially over serialized objects. We study the bounded repair problem over strings and trees restricted to this streaming setting and show that this variant can be characterized in terms of finite games. Furthermore, we use this characterization to decide whether one can repair a pair of specifications in a streaming fashion with bounded cost and how to obtain a streaming repair strategy in this case. The previous notion asks for a uniform bound on the number of edits, but having this property is a strong requirement. To overcome this limitation, we study how to calculate the maximum number of edits per character needed to repair any object in R into T. We formalize this as the asymptotic cost -- the limit of the number of edits divided by the length of the input in the worst case. Our contribution is an algorithm to compute the asymptotic cost for any pair of regular specifications over strings. We also consider the streaming variant of this cost and we show how to compute it by reducing this problem to mean-payoff games.

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Preuksakarn, Chakkrit. « Reconstructing plant architecture from 3D laser scanner data ». Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20116/document.

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Les modèles virtuels de plantes sont visuellement de plus en plus réalistes dans les applications infographiques. Cependant, dans le contexte de la biologie et l'agronomie, l'acquisition de modèles précis de plantes réelles reste un problème majeur pour la construction de modèles quantitatifs du développement des plantes.Récemment, des scanners laser 3D permettent d'acquérir des images 3D avec pour chaque pixel une profondeur correspondant à la distance entre le scanner et la surface de l'objet visé. Cependant, une plante est généralement un ensemble important de petites surfaces sur lesquelles les méthodes classiques de reconstruction échouent. Dans cette thèse, nous présentons une méthode pour reconstruire des modèles virtuels de plantes à partir de scans laser. Mesurer des plantes avec un scanner laser produit des données avec différents niveaux de précision. Les scans sont généralement denses sur la surface des branches principales mais recouvrent avec peu de points les branches fines. Le cœur de notre méthode est de créer itérativement un squelette de la structure de la plante en fonction de la densité locale de points. Pour cela, une méthode localement adaptative a été développée qui combine une phase de contraction et un algorithme de suivi de points.Nous présentons également une procédure d'évaluation quantitative pour comparer nos reconstructions avec des structures reconstruites par des experts de plantes réelles. Pour cela, nous explorons d'abord l'utilisation d'une distance d'édition entre arborescence. Finalement, nous formalisons la comparaison sous forme d'un problème d'assignation pour trouver le meilleur appariement entre deux structures et quantifier leurs différences
In the last decade, very realistic rendering of plant architectures have been produced in computer graphics applications. However, in the context of biology and agronomy, acquisition of accurate models of real plants is still a tedious task and a major bottleneck for the construction of quantitative models of plant development. Recently, 3D laser scanners made it possible to acquire 3D images on which each pixel has an associate depth corresponding to the distance between the scanner and the pinpointed surface of the object. Standard geometrical reconstructions fail on plants structures as they usually contain a complex set of discontinuous or branching surfaces distributed in space with varying orientations. In this thesis, we present a method for reconstructing virtual models of plants from laser scanning of real-world vegetation. Measuring plants with laser scanners produces data with different levels of precision. Points set are usually dense on the surface of the main branches, but only sparsely cover thin branches. The core of our method is to iteratively create the skeletal structure of the plant according to local density of point set. This is achieved thanks to a method that locally adapts to the levels of precision of the data by combining a contraction phase and a local point tracking algorithm. In addition, we present a quantitative evaluation procedure to compare our reconstructions against expertised structures of real plants. For this, we first explore the use of an edit distance between tree graphs. Alternatively, we formalize the comparison as an assignment problem to find the best matching between the two structures and quantify their differences

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Gao, Zhiyun. « Novel multi-scale topo-morphologic approaches to pulmonary medical image processing ». Diss., University of Iowa, 2010. https://ir.uiowa.edu/etd/805.

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The overall aim of my PhD research work is to design, develop, and evaluate a new practical environment to generate separated representations of arterial and venous trees in non-contrast pulmonary CT imaging of human subjects and to extract quantitative measures at different tree-levels. Artery/vein (A/V) separation is of substantial importance contributing to our understanding of pulmonary structure and function, and immediate clinical applications exist, e.g., for assessment of pulmonary emboli. Separated A/V trees may also significantly boost performance of airway segmentation methods for higher tree generations. Although, non-contrast pulmonary CT imaging successfully captures higher tree generations of vasculature, A/V are indistinguishable by their intensity values, and often, there is no trace of intensity variation at locations of fused arteries and veins. Patient-specific structural abnormalities of vascular trees further complicate the task. We developed a novel multi-scale topo-morphologic opening algorithm to separate A/V trees in non-contrast CT images. The algorithm combines fuzzy distance transform, a morphologic feature, with a topologic connectivity and a new morphological reconstruction step to iteratively open multi-scale fusions starting at large scales and progressing towards smaller scales. The algorithm has been successfully applied on fuzzy vessel segmentation results using interactive seed selection via an efficient graphical user interface developed as a part of my PhD project. Accuracy, reproducibility and efficiency of the system are quantitatively evaluated using computer-generated and physical phantoms along with in vivo animal and human data sets and the experimental results formed are quite encouraging. Also, we developed an arc-skeleton based volumetric tree generation algorithm to generate multi-level volumetric tree representation of isolated arterial/venous tree and to extract vascular measurements at different tree levels. The method has been applied on several computer generated phantoms and CT images of pulmonary vessel cast and in vivo pulmonary CT images of a pig at different airway pressure. Experimental results have shown that the method is quite accurate and reproducible. Finally, we developed a new pulmonary vessel segmentation algorithm, i.e., a new anisotropic constrained region growing method that encourages axial region growing while arresting cross-structure leaking. The region growing is locally controlled by tensor scale and structure scale and anisotropy. The method has been successfully applied on several non-contrast pulmonary CT images of human subjects. The accuracy of the new method has been evaluated using manually selection of vascular and non-vascular voxels and the results found are very promising.

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Ghadie, Mohamed A. « Analysis and Reconstruction of the Hematopoietic Stem Cell Differentiation Tree : A Linear Programming Approach for Gene Selection ». Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32048.

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Stem cells differentiate through an organized hierarchy of intermediate cell types to terminally differentiated cell types. This process is largely guided by master transcriptional regulators, but it also depends on the expression of many other types of genes. The discrete cell types in the differentiation hierarchy are often identified based on the expression or non-expression of certain marker genes. Historically, these have often been various cell-surface proteins, which are fairly easy to assay biochemically but are not necessarily causative of the cell type, in the sense of being master transcriptional regulators. This raises important questions about how gene expression across the whole genome controls or reflects cell state, and in particular, differentiation hierarchies. Traditional approaches to understanding gene expression patterns across multiple conditions, such as principal components analysis or K-means clustering, can group cell types based on gene expression, but they do so without knowledge of the differentiation hierarchy. Hierarchical clustering and maximization of parsimony can organize the cell types into a tree, but in general this tree is different from the differentiation hierarchy. Using hematopoietic differentiation as an example, we demonstrate how many genes other than marker genes are able to discriminate between different branches of the differentiation tree by proposing two models for detecting genes that are up-regulated or down-regulated in distinct lineages. We then propose a novel approach to solving the following problem: Given the differentiation hierarchy and gene expression data at each node, construct a weighted Euclidean distance metric such that the minimum spanning tree with respect to that metric is precisely the given differentiation hierarchy. We provide a set of linear constraints that are provably sufficient for the desired construction and a linear programming framework to identify sparse sets of weights, effectively identifying genes that are most relevant for discriminating different parts of the tree. We apply our method to microarray gene expression data describing 38 cell types in the hematopoiesis hierarchy, constructing a sparse weighted Euclidean metric that uses just 175 genes. These 175 genes are different than the marker genes that were used to identify the 38 cell types, hence offering a novel alternative way of discriminating different branches of the tree. A DAVID functional annotation analysis shows that the 175 genes reflect major processes and pathways active in different parts of the tree. However, we find that there are many alternative sets of weights that satisfy the linear constraints. Thus, in the style of random-forest training, we also construct metrics based on random subsets of the genes and compare them to the metric of 175 genes. Our results show that the 175 genes frequently appear in the random metrics, implicating their significance from an empirical point of view as well. Finally, we show how our linear programming method is able to identify columns that were selected to build minimum spanning trees on the nodes of random variable-size matrices.

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Bonada, i. Cruells Eduard. « Building ethernet connectivity services for provider networks ». Doctoral thesis, Universitat Pompeu Fabra, 2012. http://hdl.handle.net/10803/85413.

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Network providers are motivated to deploy Ethernet in their infrastructures. However, this represents a new application for Ethernet technology that leads to new requirements. In Ethernet networks, the Rapid Spanning Tree Protocol (RSTP) creates an active tree on top of the physical topology to avoid potential loops and allows the bridge functionalities to work properly. However, there are some implications of using RSTP to prune the physical topology into an active tree: unused links and sub-optimal paths. In addition, RSTP suffers count-to-infinity and takes too long to recover from critical failures. In this thesis we propose a complete solution based on RSTP extensions that addresses the shortcomings. We design and evaluate two extensions: RSTP-Conf to provide quick recoveries and RSTP-SP to operate with optimal path communications.
Els proveïdors de xarxa estan motivats per implementar Ethernet en les seves infraestructures. No obstant, això representa una nova aplicació per Ethernet que comporta nous requeriments. En les xarxes Ethernet, el protocol de Rapid Spanning Tree (RSTP) crea un arbre actiu per evitar cicles i permetre que les xarxes Ethernet funcionin correctament. Hi ha però algunes implicacions de l'ús de RSTP per transformar la topologia física en un arbre actiu: alguns enllaços no utilitzats i la creació de rutes sub-òptimes. A més, RSTP pateix count-to-infinity i tarda massa temps per recuperar-se de caigudes crítiques. En aquesta tesi es proposa una solució completa basada en extensions d’RSTP que aborda les seves deficiències. Dissenyem i avaluem dues extensions: RSTP-Conf per proporcionar una ràpida recuperació i RSTP-SP per operar amb comunicacions per camins òptims.

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Santos, Edméa Oliveira dos. « O currículo e o digital : educação presencial e a distância ». reponame:Repositório Institucional da UFBA, 2002. http://www.repositorio.ufba.br/ri/handle/ri/11775.

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141 f.
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Terceiro Milênio. Estamos inaugurando um novo século num contexto de agenciamentos sócio-técnicos diversos. As novas tecnologias digitais de informação e comunicação vêm condicionando mudanças paradigmáticas nos campos da economia, nas relações sociais e culturais principalmente nas formas e meios de produção e socialização de saberes e conhecimentos. Nesse contexto as relações de aprendizagem vêm se configurando por novas bases. O currículo fragmentado, disciplinar, linear, descontextualizado da vida e desejo dos sujeitos está sendo posto em xeque. Este trabalho procurou analisar, através de estudo de casos, práticas curriculares de educação presencial (uso do software Árvore de Conhecimentos no curso de pós-graduação em Comunicação e Semiótica da PUC-SP) e a distância (curso de extensão oferecido pela UVB - Universidade Virtual Brasileira) estruturadas por dispositivos comunicacionais, interfaces digitais. O estudo evidenciou a tensão entre o campo instituído do currículo (grade curricular, programas, linhas de pesquisa) e seu campo instituinte (movimentos dos sujeitos na ação comunicativa). As tecnologias digitais de comunicação, não garantem por si só, mudanças nas práticas curriculares, mas podem potencializa-las, pois permite a emergência de um coletivo mais comunicativo, independente da sua localização espaço/temporal.
Salvador

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Collins, Karen L. (Karen Linda). « Distance matrices of trees ». Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/77687.

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Aymak, Onur. « Ad Hoc Packet Routing Simulation And Tactical Picture Display Tool For Navy ». Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/2/12605266/index.pdf.

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The importance of communication is vital in wartime. The capability of having all the position information of the allied and enemy forces in a single Tactical Information Display System (TIDS), maintains a great advantage for deciding what to do before the enemy reacts. A Naval Information Distributing System (NIDS) is developed for building an effective communication infrastructure between the war ships. In the designed network, besides the mobile platforms (ships), some fixed platforms (land stations) are used to transfer the information coming from these mobile platforms to all the other platforms. To demonstrate the performance and effectiveness of the Naval Information Distribution System, a discrete event simulation model is developed on a Geographic Information System. The goal of this thesis is to describe and experimentally evaluate an effective and feasible information sharing and routing system for Navy.

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Schläppy, Romain. « Snow avalanche hazard assessment in the French Alps using a combination of dendrogeomorphic and statistical approaches ». Thesis, Paris 1, 2014. http://www.theses.fr/2014PA010679/document.

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Les avalanches sont susceptibles d’affecter le réseau routier et les infrastructures bâties, mettant en péril la population. L’extension des avalanches est généralement évaluée à l’aide de modèles physiques et/ou statistiques. Ces modèles sont très performants pour simuler des événements relativement fréquents, cependant, les incertitudes augmentent dès lors que l’on considère des événements plus rares. Il est donc indispensable de valider les procédures de modélisation afin de confirmer les prédictions qui en découlent. Dans ce travail, la dendrogéomorphologie a été utilisée comme un outil de validation. Cette approche se fonde sur le fait que les arbres forment un cerne de croissance par année et que les individus affectés par des processus naturels enregistrent l’évidence d’une perturbation dans leurs cernes. Cette thèse a permis de proposer une nouvelle approche pour l’identification des événements avalancheux fondée sur l’expertise du dendrogéomorphologue et d’évaluer la qualité de l’approche dendrogéomorphologique. Il a également été possible de réaliser une validation croisée entre des avalanches extrêmes prédites par un modèle statistique-dynamique et des informations sur des périodes de retour d’avalanches similaires obtenues à l’aide de l’approche dendrogéomorphologique. Les résultats montrent une très bonne concordance pour des événements dont la période de retour est égale ou inférieure à 300 ans. Finalement, une analyse des relations statistiques avalanche-climat a montré que les arbres enregistrent préférentiellement les événements qui ont eu lieu durant des épisodes froids associés à des tempêtes hivernales accompagnées de fortes précipitations
Snow avalanches are a significant natural hazard that impact roads, structures and threaten human lives in mountainous terrain. The extent of avalanches is usually evaluated using topographic or statistic models. These models are well capable to simulate contemporary events, but uncertainties increase as soon as longer return periods are investigated. Thus, there is a real need for validation of modelling procedures to corroborate model predictions. In the present work, dendrogeomorphology has been used as a validation tool. This approach is based on the fact that trees affected by mass movements record the evidence of geomorphic disturbance in their growth-ring series and thereby provide a precise geochronological tool for the reconstruction of past mass movement activity. This PhD thesis presents a new tree-ring-based semi-quantitative approach for the identification of avalanche events based on the analytical skills of the dendrogeomorphic expert and proposes an evaluation of the completeness of tree-ring records. Furthermore, this work proposes the first cross-validation of high return period avalanches derived from a locally calibrated statistical-dynamical model and the long-term, higher-return period information gathered from tree-ring records. Comparison of relations between runout distances and return periods between both approaches shows very good agreement for events with return periods of < 300 yr. Finally, a statistical analysis of avalanche-climate relations suggests that tree rings preferentially record events that occurred during cold winter storms with heavy precipitation

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Amavi, Joshua. « Comparaison et évolution de schémas XML ». Thesis, Orléans, 2014. http://www.theses.fr/2014ORLE2053/document.

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XML est devenu le format standard d’échange de données. Nous souhaitons construire un environnement multi-système où des systèmes locaux travaillent en harmonie avec un système global, qui est une évolution conservatrice des systèmes locaux. Dans cet environnement, l’échange de données se fait dans les deux sens. Pour y parvenir nous avons besoin d’un mapping entre les schémas des systèmes. Le but du mapping est d’assurer l’évolution des schémas et de guider l’adaptation des documents entre les schémas concernés. Nous proposons des outils pour faciliter l’évolution de base de données XML. Ces outils permettent de : (i) calculer un mapping entre le schéma global et les schémas locaux, et d’adapter les documents ; (ii) calculer les contraintes d’intégrité du système global à partir de celles des systèmes locaux ; (iii) comparer les schémas de deux systèmes pour pouvoir remplacer un système par celui qui le contient ; (iv) corriger un nouveau document qui est invalide par rapport au schéma d’un système, afin de l’ajouter au système. Des expériences ont été menées sur des données synthétiques et réelles pour montrer l’efficacité de nos méthodes
XML has become the de facto format for data exchange. We aim at establishing a multi-system environment where some local original systems work in harmony with a global integrated system, which is a conservative evolution of local ones. Data exchange is possible in both directions, allowing activities on both levels. For this purpose, we need schema mapping whose is to ensure schema evolution, and to guide the construction of a document translator, allowing automatic data adaptation wrt type evolution. We propose a set of tools to help dealing with XML database evolution. These tools are used : (i) to compute a mapping capable of obtaining a global schema which is a conservative extension of original local schemas, and to adapt XML documents ; (ii) to compute the set of integrity constraints for the global system on the basis of the local ones ; (iii) to compare XML types of two systems in order to replace a system by another one ; (iv) to correct a new document with respect to an XML schema. Experimental results are discussed, showing the efficiency of our methods in many situations

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Dinc, Havva. « Alu Insertion Polymorphisms In Anatolian Turks ». Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1169929/index.pdf.

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In the present study
ten autosomal human-specific Alu insertion polymorphisms
ACE, APO, A25, B65, D1, FXIIIB, HS4.32, HS4.69, PV92 and TPA25 were analyzed in approximately 100 unrelated individuals from Anatolia. Alu insertion polymorphisms offer several advantages over other nuclear DNA polymorphisms for human evolution studies. The frequencies of the ten biallelic Alu insertions in Anatolians were calculated and all systems were found to be in Hardy-Weinberg equilibrium (p>
0.05). By combining the results of this study with results of previous studies done on worldwide populations, the genetic distance (Nei&rsquo
s DA) between each pair of populations was calculated and neighbor joining trees were constructed. In general, geographically closer populations were found to be also genetically similar. Principal component analysis (PCA) was performed and Anatolia was found to be in the European cluster. As a result of PCA
it was concluded that FXIIIB, PV92 and ACE were the variables contributing the most to the explanation of the variation between the populations. Additionally
canonical variates analysis (CVA) concluded that the most discriminative markers for the groups of populations were PV92, D1, ACE and HS4.32. Pair-wise Fst values were also calculated between Anatolians and some of the populations for which the data was available. It was concluded that, Anatolians have non-significant pair-wise Fst values with Swiss and French Acadian populations. Lastly, heterozygosity vs. distance from centroid graph was constructed and it was found that Anatolians and India-Hindu had exactly the expected heterozygosity value predicted by the model of Harpending and Ward (1982).

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Suliman, Tammam [Verfasser], Uta [Gutachter] Berger, der Maaten-Theunissen Mareike [Gutachter] van et Wael [Gutachter] Ali. « Understanding the dynamics of even-aged stands of Brutia pine (Pinus brutia Ten.) in the coastal region of Syria based on a distance-independent individual-tree growth model / Tammam Suliman ; Gutachter : Uta Berger, Mareike van der Maaten-Theunissen, Wael Ali ». Dresden : Technische Universität Dresden, 2020. http://d-nb.info/1227833695/34.

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McCaffery, Martin. « The mat sat on the cat : investigating structure in the evaluation of order in machine translation ». Thesis, University of St Andrews, 2017. http://hdl.handle.net/10023/12080.

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We present a multifaceted investigation into the relevance of word order in machine translation. We introduce two tools, DTED and DERP, each using dependency structure to detect differences between the structures of machine-produced translations and human-produced references. DTED applies the principle of Tree Edit Distance to calculate edit operations required to convert one structure into another. Four variants of DTED have been produced, differing in the importance they place on words which match between the two sentences. DERP represents a more detailed procedure, making use of the dependency relations between words when evaluating the disparities between paths connecting matching nodes. In order to empirically evaluate DTED and DERP, and as a standalone contribution, we have produced WOJ-DB, a database of human judgments. Containing scores relating to translation adequacy and more specifically to word order quality, this is intended to support investigations into a wide range of translation phenomena. We report an internal evaluation of the information in WOJ-DB, then use it to evaluate variants of DTED and DERP, both to determine their relative merit and their strength relative to third-party baselines. We present our conclusions about the importance of structure to the tools and their relevance to word order specifically, then propose further related avenues of research suggested or enabled by our work.

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Al-Qasem, Ruby. « True Selves : Narrative Distance in Stories of Fiction and Nonfiction ». Thesis, University of North Texas, 2009. https://digital.library.unt.edu/ark:/67531/metadc12069/.

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True Selves: Narrative Distance in Stories of Fiction and Nonfiction consists of a scholarly preface and four creative works. The preface discusses narrative distance as used in both fiction and nonfiction, and as compares to other narrative agents such as point of view, especially in contemporary creative writing. The selection of stories examines relationships, especially familial, and themes of isolation, community, and memory. Collection includes two chapters of a novel-in-progress, Fences, short fiction story "Trees and Furniture," and creative nonfiction essays, "Floating" and "On the Sparrow."

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Al-Qasem, Ruby Rodman Barbara Ann. « True selves narrative distance in stories of fiction and nonfiction / ». [Denton, Tex.] : University of North Texas, 2009. http://digital.library.unt.edu/ark:/67531/metadc12069.

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Huff, Paul A. « PyAline : Automatically Growing Language Family Trees Using the ALINE Distance ». BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2389.

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Several methods for determining a numerical distance between languages have been proposed in the literature. In this thesis I implement one of them, the ALINE distance, and develop a methodology for comparing its results with other language distance metrics. I then compare it with a leading distance metric, the LDND distance, proposed by the ASJP project.

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Zaina, Luciana Aparecida Martinez. « Acompanhamento do aprendizado do aluno em cursos à distância através da Web : metodologias e ferramenta ». Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/3/3141/tde-13012003-095336/.

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O crescimento de cursos a distância oferecidos através da Web tem promovido uma grande reflexão sobre como acompanhar a evolução do aluno através deste curso. Em um curso presencial o docente possui meios mais seguros e concretos de observar e gerenciar o processo de aprendizagem já que os participantes estão em contato físico constante. Além disto, normalmente em um curso a distância, o aluno faz seu horário de estudo o que resulta num esforço ainda maior por parte do docente para acompanhar os alunos, pois terá que analisar momentos diferentes do curso ao mesmo tempo. A escolha de métodos para acompanhar a evolução do estudante em um curso on-line é sempre muito difícil de ser realizada e deve ser adequada as necessidades específicas do contexto estudado. Este trabalho apresenta além de conceitos pedagógicos relacionados a avaliação da aprendizagem presencial ambientes de gerenciamento de cursos a distância através da Web, sendo estes os alicerces das propostas realizadas nesta dissertação. As alternativas apresentadas, dentro de um ambiente interativo e através de testes objetivos, para realização de uma avaliação formativa tem como principal objetivo acompanhar o desenvolvimento do aluno no processo de aprendizagem. Como resultado da aplicação da metodologia para a construção de testes objetivos obteve-se uma ferramenta denominada AvaliaOnline, cuja finalidade é criar e aplicar questões do tipo múltipla-escolha em problemas que possuem valores numéricos e fórmulas ou algoritmos relacionados a sua resolução. A ferramenta permite que os valores numéricos que constituem o enunciado de uma questão sejam modificados toda vez que a mesma é apresentada, através do sorteio aleatório destes valores que serão utilizados para resolução do problema. Ou seja, a resposta correta da questão é gerada no momento da exibição da mesma. Além disto, é possível realizar uma dependência entre as questões que constituem o teste, construíndo uma árvore de questões onde o docente verifica o caminho percorrido pelo aluno durante o teste, dando subsídios para um acompanhamento mais detalhado sobre a resolução do estudante. Finalizando este trabalho, são apresentados exemplos práticos da utilização das ferramentas interativas para acompanhamento do aluno e da criação e aplicação de um teste desenvolvido através da ferramenta AvaliaOnline.
The increase in the number of distance courses in the Web has caused much reflection on how to track the students evolution through this course. In a live course it is possible for the teacher to observe and manage the learning process through safer and more concrete ways, once the participants are in constant physical contact. In addition, in a distance course the student usually determines how many hours he must study as well as when he will be studying. This will demand a bigger effort on the part of the teacher to track students once he may have to analyse different moments of the course at the same time. The choice of methods to track the stucents evolution in an on-line course is always very difficult to be made and it must be suitable to the specific needs of the studied context. This work presents pedagogical concepts related to tradicional learning evaluation as well as distance course managing environments through the Web, having these as the foundations of the proposals made in this dissertation. The alternatives presented, in an interactive environment and through objective tests, in order to have a formative evaluation, have as their main goal to track the development of the student in the learning process. As a result of the application of methodology for the construction of objective tests, a tool named AvaliaOnline was obtained, whose aim is to create and apply multiple-choice type questions to problems that have numerical values and formulas or algorithms related to their resolution. The tool allows the numerical values in the description of a question to be modified every time it is presented, through random sorting out of these values, which will be used for the resolution of the problem, that is, the correct answer of the question is produced at the moment of its exhibition. Besides, it is possible to establish dependence among the test questions, building a tree of questions where the teacher verifies the path followed by the student during the test, providing support for more detailed tracking on the resolution of the student. At the end of this work, practical examples are presented on the use of interactive tools to track the student and on the creation and application of a test developed through the tool AvaliaOnline. The experiments made show the potencial of such alternatives once they are used in a suitable context and under teacher tracking with.

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Richter, Yoram 1971. « Distant hemodynamic impact of local geometric alterations in the arterial tree ». Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/29944.

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Thesis (Ph. D.)--Harvard-MIT Division of Health Sciences and Technology, 2003.
Includes bibliographical references (leaves 164-169).
Hemodynamics has long been identified as a major factor in the determination and localization of atherosclerotic lesions. While the precise mechanism by which different hemodynamic factors act is not yet clear, the fact that they correlate highly with atherogenesis suggests that local disturbances in flow through blood vessels can promote arterial disease. These issues have become increasingly acute as physicians seek to alter the pathological arterial anatomy with bypass grafting or endovascular manipulations such as angioplasty or stenting. We proposed that local vascular interventions might cause previously unforeseen effects elsewhere in the arterial tree. As an example of these interactions, manipulation of one branch of a bifurcation might adversely affect the contralateral branch of the bifurcation. The goal of this work was to study the distant impact of local flow alterations, as well as to classify and evaluate the different parameters that determine their severity. Dynamic flow models of the arterial system were developed that allowed for the continuous alteration of model geometry in a controlled fashion to simulate the healthy and diseased states as well as the entire range in between. Moreover, these models permit simulation of different strategies of clinical intervention. Flow through the models was investigated using both qualitative and quantitative tools. Boundary layer separation and vascular resistance in one location of the arterial tree varied with geometrical alterations in another. In-vivo models were developed that allowed investigation of the effect of side branch occlusion or dilation on the acute and chronic outcome of main branch stenting in a bifurcation. Chronic side branch occlusions were protective of main branch stenting as reflected by a reduction in in-stent neo-intimal hyperplasia.
(cont.) This protective influence was mediated by an acute modulation of monocyte adhesion and accumulation on the lateral wall of the main branch, correlating with the location of flow disturbance demonstrated by the flow models. Chronic main branch vascular remodeling plays a major role in achieving this beneficial effect. The results of this study could have important implications for the diagnosis, treatment and long-term follow-up of the large number of patients who suffer from complex arterial diseases and undergo vascular interventions. In clinical manipulation of one arterial site one may well need to consider the hemodynamic impact on vascular segments at a distance.
by Yoram Richter.
Ph.D.

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Richter, Yoram 1971. « Distant hemodynamic impact of local geometric alterations in the arterial tree ». Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/29548.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.
Includes bibliographical references (leaf 96).
Hemodynamics has long been identified as a major factor in the determination and localization of atherosclerotic lesions. Atherosclerosis is focal and often forms in specific locations in the arterial tree such as bifurcations. Many different aspects of fluid mechanics have been suggested as the trigger for atherogenesis - non-laminar and/or unstable flow, flow separation, regions of higher/lower and/or oscillatory shear stress etc. While the precise mechanism by which these hemodynamic factors act is not yet clear, the fact that they correlate highly with atherogenesis suggests that local disturbances in flow through blood vessels can promote arterial disease. These issues have become increasingly acute as physicians seek to alter the pathological arterial anatomy with bypass grafting or endovascular manipulations such as angioplasty or stenting. We proposed that vascular interventions might cause previously unforeseen effects in the arterial tree especially at branch points. Manipulation of one branch of a bifurcation might adversely affect the contralateral branch of the bifurcation. The goal of this work was to study the distant impact of local flow alterations, as well as to classify and evaluate the different parameters that determine their severity. Dynamic flow models of the arterial system were developed that allowed for the continuous alteration of model geometry in a controlled fashion. This property allows for the simulation not only of the healthy or diseased states, but also of the entire range in between. Moreover, these models permit simulation of different strategies of clinical intervention. Flow through the models was investigated using both qualitative (flow visualization) and quantitative (flow and pressure readings) tools. Flow separation and vascular resistance in one location of the arterial tree varied with geometrical alterations in another. The results of this study could have important implications for the diagnosis, treatment and long-term follow-up of the large number of patients who suffer from these diseases and undergo vascular interventions. Clinical arterial manipulation of one arterial site may well need to consider the hemodynamic impact on vascular segments at a distance.
by Yoram Richter.
S.M.

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Sanchez, Inès. « Etude de la variabilite enzymatique de terminalia superba engler et diels : arbre forestier d'afrique tropicale ». Paris 7, 1988. http://www.theses.fr/1988PA077148.

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ZOUACHE, NOUREDDINE. « Mecanismes de disruption dans le vide a tres petites distances ». Clermont-Ferrand 2, 1997. http://www.theses.fr/1997CLF21904.

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Une meilleure connaissance des mecanismes conduisant a la ruptrue de l'isolement est essentielle, pour la conception et l'amelioration des performances des appareils haute tension a usage industriel. Les alliages et pseudo-alliages a base d'argent, offrent aux constructeurs d'appareils de coupure un meilleur compromis, entre le cout et les performances des materiaux de contacts. L'etude de disruption pour ces materiaux presente un interet sur le plan fondamental vu leur nature composite. Le dispositif experimental comprend un groupe de pompage ultra-vide, un systeme de montage et de reglage d'ecartement des electrodes, une installation electrique et des moyens de mesure le conditionnement des electrodes, fait augmenter la tension d'amorcage suivant une loi exponentielle qui nous renseigne sur les modifications et de la surface. Les mesures de la tension d'amorcage, du temps de commutation, du temps de retard, ainsi que les observations au microscope electronique et l'analyse par spectrometrie x de la surface des electrodes apres l'amorcage, nous ont permis de montrer principalement les phenomenes suivants : - pour la plupart des materiaux etudies, le processus initiateur de la decharge dans le vide, a l'echelle du micrometre, est l'emission electronique. L'amorcage est de type anodique pour l'argent et l'agcdo, et cathodique pour les agni et l'agsno#2. - l'augmentation du pourcentage du nickel dans l'alliage agni, permet d'obtenir une amelioration de l'isolation de l'espace interelectrodes. - pour l'agcdo, la decomposition du cdo absorbe une partie de l'energie de la decharge, ce qui limite l'erosion de l'anode. - pour l'agzno, la disruption est instantanee par contact local des electrodes pour les tres faibles ecartements interelectrodes, et par impact d'une microparticule sur la surface cathodique pour les distances les plus grandes. - pour l'ensemble des materiaux etudies, l'initiation et le developpement de la decharge dans le vide, dependent de l'etat microscopique de la surface des electrodes et de ses proprietes thermiques, emissives et mecaniques. La determination photoelectrique du travail de sortie des alliages metalliques agw (50/50) et agcw (50/50), a montre que pour un alliage metallique binaire a#xb#1#-#x, la valeur de son travail de sortie est une fonction lineaire de la proportion atomique x.

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ブラーエヴァ, マリアエドアルドヴナ, Maria Eduardovna BULAEVA, Katsuo TAMAOKA, Yulei HUANG, 賀津雄玉岡 et 郁蕾黄. « 中国語母話者の日本学習によるポライトネスの構造と意識の変容 : 依頼に対する断り難さに着目して ». 名古屋大学言語文化研究会, 2014. http://hdl.handle.net/2237/20907.

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Williams, Vincent Troy. « An Experimental Study of Distance Sensitivity Oracles ». Scholar Commons, 2010. http://scholarcommons.usf.edu/etd/3697.

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The paper \A Nearly Optimal Oracle for Avoiding Failed Vertices and Edges" by Aaron Bernstein and David Karger lays out a nearly optimal algorithm for nding the shortest distances and paths between vertices with any given single failure in constant time without reconstructing the oracle. Using their paper as a guideline, we have implemented their algorithm in C++ and recorded each step in this thesis. Each step has its own pseudo-code and its own analysis to prove that the entire oracle construction stays within the stated running time and total space bounds, from the authors. The effciency of the algorithm is compared against that of the brute-force methods total running time and total space needed. Using multiple test cases with an increasing number of vertices and edges, we have experimentally validated that their algorithm holds true to their statements of space, running time, and query time.

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Vadják, Šimon. « Statistické vyhodnocení fylogeneze biologických sekvencí ». Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-221143.

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The master's thesis provides a comprehensive overview of resampling methods for testing the correctness topology of the phylogenetic trees which estimate the process of phylogeny on the bases of biological sequences similarity. We focused on the possibility of errors creation in this estimate and the possibility of their removal and detection. These methods were implemented in Matlab for Bootstrapping, jackknifing, OTU jackknifing and PTP test (Permutation tail probability). The work aims to test their applicability to various biological sequences and also to assess the impact of the choice of input analysis parameters on the results of these statistical tests.

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Pedralho, André de Souza. « Extração automática de dados de páginas HTML utilizando alinhamento em dois níveis ». Universidade Federal do Amazonas, 2011. http://tede.ufam.edu.br/handle/tede/2897.

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Made available in DSpace on 2015-04-11T14:02:41Z (GMT). No. of bitstreams: 1 andre.pdf: 821975 bytes, checksum: 8b72d2493d068d6a827082e5eb108bf6 (MD5) Previous issue date: 2011-07-28
There is a huge amount of information in the World Wide Web in pages composed by similar objects. E-commerce Web sites and on-line catalogs, in general, are examples of such data repositories. Although this information usually occurs in semi-structured texts, it is designed to be interpreted and used by humans and not processed by machines. The identification of these objects inWeb pages is performed by external applications called extractors or wrappers. In this work we propose and evaluate an automatic approach to the problem of generating wrappers capable of extracting and structuring data records and the values of their attributes. It uses the Tree Alignment Algorithm to find in the Web page examples of objects of interest. Then, our method generates regular expressions for extracting objects similar to the examples given using the Multiple Sequence Alignment Algorithm. In a final step, the method decomposes the objects in sequences of text using the regular expression and common formats and delimiters, in order to identify the value of the attributes of the data records. Experiments using a collection composed by 128 Web pages from different domains have demonstrated the feasibility of our extraction method. It is evaluated regarding the identification of blocks of HTML source code that contain data records and regarding record extraction and the value of its attributes. It reached a precision of 83% and a recall of 80% when extracting the value of attributes. These values mean a gain in precision of 43.37% and in recall of 68.75% when compared to similar proposals.
Existe uma grande quantidade de informação na World Wide Web em páginas compostas por objetos similares. Web sites de comércio eletrônico e catálogos online, em geral, são exemplos destes repositórios de dados. Apesar destes dados serem apresentados em porções de texto semi-estruturados, são projetados para serem interpretados e utilizados por humanos e não processados por máquinas. A identificação destes objetos em páginas Web é feita por aplicações externas chamadas extratores ou wrappers. Neste trabalho propomos e avaliamos um método automático para o problema de extrair e estruturar registros e valores de seus atributos presentes em páginas Web ricas em dados. O método utiliza um Algoritmo de Alinhamento de Árvores para encontrar nestas páginas exemplos de registros que correspondem a objetos de interesse. Em seguida, o método gera expressões regulares para extrair objetos similares aos exemplos dados usando o Algoritmo de Alinhamento de Múltiplas Sequências. Em um passo final, o método decompõe os registros em sequências de texto aplicando a expressão regular criada e formatações e delimitadores comuns, com o intuito de identificar os valores dos atributos dos registros. Experimentos utilizando uma coleção composta por 128 páginasWeb de diferentes domínios demonstram a viabilidade do nosso método de extração. O método foi avaliado em relação à identificação de blocos de código HTML que contêm os registros e quanto à extração dos registros e dos valores de seus atributos. Obtivemos precisão de 83% e revocação de 80% na extração de valores de atributos. Estes valores significam um ganho na precisão de 43,37% e na revocação de 68,75%, em relação a propostas similares

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CALEGARI, ELENA. « La distanza conta : Tre elaborati in Economia Spaziale ». Doctoral thesis, Università Cattolica del Sacro Cuore, 2016. http://hdl.handle.net/10280/12222.

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Waldo Tobler, con la sua prima legge della geografia, afferma “Ogni cosa è correlata con qualsiasi altra, ma le cose vicine sono più relazionate di quelle lontane" (Tobler, 1970). Se questo era certamente vero nel 1970, tale convinzione è stata messa in discussione con l’avvento delle Tecnologie dell’Informazione e della Comunicazione (ICT). Nel dibattito riguardo al processo di globalizzazione molti studiosi e giornalisti sostengono infatti che, con la velocizzazione delle telecomunicazioni, la distanza fisica è destinata a perdere il proprio potere esplicativo relativamente a molti fenomeni socio-economici (Cairncross, 2001; Friedman, 2005). Questa dissertazione vuole contribuire al dibattito rispondendo, seppure parzialmente, alla domanda “La distanza importa ancora?” e definire alcune possibili implicazioni di policy. L’obiettivo è quello di mostrare il ruolo della distanza geografica in tre diversi contesti economici caratterizzati da differenti dimensioni dell’unità di analisi. I risultati suggeriscono che, anche se su scala globale lo sviluppo delle nuove tecnologie ha modificato la percezione individuale della distanza come deterrente alle interazioni, lo spazio geografico mantiene ancora la sua rilevanza del definire le relazioni socio-economiche locali, aumentando il ruolo di città e regioni quali centri della maggioranza delle attività economiche.
Waldo Tobler, with his first law of geography, stated “Everything is related to everything else, but near things are more related than distant things" (Tobler, 1970). If it was certainly true in 1970, this belief is called into question in an era of development of Information and Communication Technologies (ICTs). In the debate over globalization processes, several scholars and journalists argue indeed that, with the increasing speed of telecommunications, physical distance is losing its explanatory power as determinant of socio-economical relationships (Cairncross, 2001; Friedman, 2005). This dissertation aims to give a contribution to this debate, partially answering to the broad question “Does distance still matter?" and to draw possible policy implications. The purpose is to show the role of geographical distance in three different economic environments, characterized by diversified size of the unit of analysis. Results suggest that, even if at a global scale improvements in ICTs have changed the individual perception of the distance as deterrent in interactions, geographical space still maintains its relevance in defining local socio-economic relationships, increasing the role of cities and regions as the core of most of economic activities.

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Samuelsson, Axel. « Weighting Edit Distance to Improve Spelling Correction in Music Entity Search ». Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-210036.

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This master’s thesis project undertook investigation of whether the extant Damerau- Levenshtein edit distance measurement between two strings could be made more useful for detecting and adjusting misspellings in a search query. The idea was to use the knowledge that many users type their queries using the QWERTY keyboard layout, and weighting the edit distance in a manner that makes it cheaper to correct misspellings caused by confusion of nearer keys. Two different weighting approaches were tested, one with a linear spread from 2/9 to 2 depending on the keyboard distance, and the other had neighbors preferred over non-neighbors (either with half the cost or no cost at all). They were tested against an unweighted baseline as well as inverted versions of themselves (nearer keys more expensive to replace) against a dataset of 1,162,145 searches. No significant improvement in the retrieval of search results were observed when compared to the baseline. However, each of the weightings performed better than its corresponding inversion on a p < 0.05 significance level. This means that while the weighted edit distance did not outperform the baseline, the data still clearly points toward a correlation between the physical position of keys on the keyboard, and what spelling mistakes are made.
Detta examensarbete åtog sig att undersöka om det etablerade Damerau-Levenshtein-avståndet som mäter avståndet kan anpassas för att bättre hitta och korrigera stavningsfel i sökfrågor. Tanken var att använda det faktum att många användare skriver sina sökfrågor på ett tangentbord med QWERTY-layout, och att vikta ändrings- avståndet så att det blir billigare att korrigera stavfel orsakade av hopblandning av två knappar som är närmare varandra. Två olika viktningar testades, en hade vikterna utspridda linjärt mellan 2/9 och 2, och den andra föredrog grannar över icke-grannar (antingen halva kostnaden eller ingen alls). De testades mot ett oviktat referensavstånd samt inversen av sig själva (så att närmare knappar blev dyrare att byta ut) mot ett dataset bestående av 1 162 145 sökningar. Ingen signifikant förbättring uppmättes gentemot referensen. Däremot presterade var och en av viktningarna bättre än sin inverterade motpart på konfidensnivå p < 0,05. Det innebär att trots att de viktade distansavstånden inte presterade bättre än referensen så pekar datan tydligt mot en korrelation mellan den fysiska positioneringen av knapparna på tangentbordet och vilka stavningsmisstag som begås.

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DI, NUOVO ELISA. « VALICO-UD : annotating an Italian learner corpus ». Doctoral thesis, Università degli studi di Genova, 2022. http://hdl.handle.net/11567/1095350.

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Previous work on learner language has highlighted the importance of having annotated resources to describe the development of interlanguage. Despite this, few learner resources, mainly for English L2, feature error and syntactic annotation. This thesis describes the development of a novel parallel learner Italian treebank, VALICO-UD. Its name suggests two main points: where the data comes from—i.e. the corpus VALICO, a collection of non-native Italian texts elicited by comic strips—and what formalism is used for linguistic annotation—i.e. Universal Dependencies (UD) formalism. It is a parallel treebank because the resource provides for each learner sentence (LS) a target hypothesis (TH) (i.e., parallel corrected version written by an Italian native speaker) which is in turn annotated in UD. We developed this treebank to be exploitable for interlanguage research and comparable with the resources employed in Natural Language Processing tasks such as Native Language Identification or Grammatical Error Identification and Correction. VALICO-UD is composed of 237 texts written by English, French, German and Spanish native speakers, which correspond to 2,234 LSs, each associated with a single TH. While all LSs and THs were automatically annotated using UDPipe, only a portion of the treebank made of 398 LSs plus correspondent THs has been manually corrected and released in May 2021 in the UD repository. This core section features also an explicit XML-based annotation of the errors occurring in each sentence. Thus, the treebank is currently organized in two sections: the core gold standard—comprising 398 LSs and their correspondent THs—and the silver standard—consisting of 1,836 LSs and their correspondent THs. In order to contribute to the computational investigation about the peculiar type of texts included in VALICO-UD, this thesis describes the annotation schema of the resource, provides some preliminary tests about the performance of UDPipe models on this treebank, reports on inter-annotator agreement results for both error and linguistic annotation, and suggests some possible applications.

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Sorwar, Golam 1969. « A novel distance-dependent thresholding strategy for block-based performance scalability and true object motion estimation ». Monash University, Gippsland School of Computing and Information Technology, 2003. http://arrow.monash.edu.au/hdl/1959.1/5510.

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Nakache, Elie. « Chemin optimal, conception et amélioration de réseaux sous contrainte de distance ». Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4023/document.

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Cette thèse porte sur différents problèmes d'optimisation combinatoire dont nous avons caractérisé la difficulté en décrivant des réductions et des algorithmes polynomiaux exacts ou approchés.En particulier, nous étudions le problème de trouver, dans un graphe orienté sans cycle dont les sommets sont étiquetés, un chemin qui passe par un maximum d'étiquettes différentes. Nous établissons qu'il n'existe pas d'algorithme polynomial avec un facteur constant pour ce problème. Nous présentons aussi un schéma qui permet d'obtenir, pour tout $epsilon >0$, un algorithme polynomial qui calcule un chemin collectant $ O(OPT^{1-epsilon})$ étiquettes.Nous étudions ensuite des variantes du problème de l'arbre couvrant de poids minimum auquel nous ajoutons des contraintes de distance et d'intermédiarité. Nous prouvons que certaines variantes se résolvent en temps polynomial comme des problèmes de calcul d'un libre de poids minimum commun à deux matroïdes. Pour une autre variante, nous présentons un algorithme d'approximation facteur 2 et nous prouvons qu'il n'existe pas d'algorithme polynomial avec un meilleur facteur constant.Enfin, nous étudions un problème d'améliorations de réseaux du point de vue du partage des coûts. Nous montrons que la fonction de coût associée à ce problème est sous-modulaire et nous utilisons ce résultat pour déduire un mécanisme de partage des coûts qui possède plusieurs bonnes propriétés
In this thesis, we investigate several combinatorial optimization problems and characterize their computational complexity and approximability by providing polynomial reductions and exact or approximation algorithms.In particular, we study the problem of finding, in a vertex-labeled directed acyclic graph, a path collecting a maximum number of distinct labels. We prove that no polynomial time constant factor approximation algorithm exists for this problem. Furthermore, we describe a scheme that produces, for any $epsilon >0$, a polynomial time algorithm that computes a solution collecting $O(OPT^{1-epsilon})$ labels. Then, we study several variants of the minimum cost spanning tree problem that take into account distance and betweenness constraints. We prove that most of these problems can be solved in polynomial time using a reduction to the weighted matroid intersection problem. For an other problem, we give a factor 2 approximation algorithm and prove the optimality of this ratio.Finally, we study a network improvement problem from a cost sharing perspective. We establish that the cost function corresponding to this problem is submodular and use this result to derive a cost sharing mechanism having several good properties

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MENAGER, ERIC. « Etude du controle stereochimique a tres longue distance par des complexes organometalliques. Applications en synthese de macrolides ». Rennes 1, 1994. http://www.theses.fr/1994REN10155.

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Le travail presente dans ce memoire concerne la synthese de macrolactones insaturees possedant une partie dienique complexee a un motif fer tricarbonyle. Un premier modele a 16 chainons et portant un carbonyle en du complexe organometallique a ete envisage. Differentes voies de synthese ont ete tentees malheureusement sans succes: des difficultes inattendues sont apparues aux etapes de macrocyclisation. Ces divers essais nous ont cependant permis de choisir une methode plus efficace pour l'elaboration d'un deuxieme modele a 20 chainons qui a ete obtenu d'une maniere satisfaisante par une reaction de macrolactonisation. La structure de ce compose a ete etablie notamment a l'aide de la diffraction des rayons x. Divers essais de cycloaddition (diels-alder, 1,3-dipolaire) ou d'addition de nucleophiles varies (organocuprates ou organomanganeux) effectues sur ce dernier modele ont permis d'apprecier sa reactivite particuliere. Cette etude a ete completee par une analyse theorique effectuee par des calculs de mecanique moleculaire. Ceci nous a permis de proposer une hypothese d'equilibre conformationnel rapide pour interpreter la faible diastereoselectivite observee avec ce type de modeles non alkyles en de l'oxygene de la lactone

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Bashar, Mohammad Ehsanul. « Average case analysis of algorithms for the maximum subarray problem ». Thesis, University of Canterbury. Computer Science and Software Engineering, 2007. http://hdl.handle.net/10092/1194.

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Maximum Subarray Problem (MSP) is to find the consecutive array portion that maximizes the sum of array elements in it. The goal is to locate the most useful and informative array segment that associates two parameters involved in data in a 2D array. It's an efficient data mining method which gives us an accurate pattern or trend of data with respect to some associated parameters. Distance Matrix Multiplication (DMM) is at the core of MSP. Also DMM and MSP have the worst-case complexity of the same order. So if we improve the algorithm for DMM that would also trigger the improvement of MSP. The complexity of Conventional DMM is O(n³). In the average case, All Pairs Shortest Path (APSP) Problem can be modified as a fast engine for DMM and can be solved in O(n² log n) expected time. Using this result, MSP can be solved in O(n² log² n) expected time. MSP can be extended to K-MSP. To incorporate DMM into K-MSP, DMM needs to be extended to K-DMM as well. In this research we show how DMM can be extended to K-DMM using K-Tuple Approach to solve K-MSP in O(Kn² log² n log K) time complexity when K ≤ n/log n. We also present Tournament Approach which solves K-MSP in O(n² log² n + Kn²) time complexity and outperforms the K-Tuple

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Heinken, Thilo, Marcus Schmidt, Goddert von Oheimb, Wolf-Ulrich Kriebitzsch et Hermann Ellenberg. « Soil seed banks near rubbing trees indicate dispersal of plant species into forests by wild boar ». Universität Potsdam, 2006. http://opus.kobv.de/ubp/volltexte/2010/4647/.

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Current knowledge about processes that generate long-distance dispersal of plants is still limited despite its importance for persistence of populations and colonization of new potential habitats. Today wild large mammals are presumed to be important vectors for long-distance transport of diaspores within and between European temperate forest patches, and in particular wild boars recently came into focus. Here we use a specific habit of wild boar, i.e. wallowing in mud and subsequent rubbing against trees, to evaluate epizoic dispersal of vascular plant diaspores. We present soil seed bank data from 27 rubbing trees versus 27 control trees from seven forest areas in Germany. The mean number of viable seeds and the plant species number were higher in soil samples near rubbing trees compared with control trees. Ten of the 20 most frequent species were more frequent, and many species exclusively appeared in the soil samples near rubbing trees. The large number of plant species and seeds – approximated > 1000 per tree – in the soils near rubbing trees is difficult to explain unless the majority were dispersed by wild boar. Hooked and bristly diaspores, i.e. those adapted to epizoochory, were more frequent, above that many species with unspecialised diaspores occurred exclusively near rubbing trees. Different to plant species closely tied to forest species which occur both in forest and open vegetation, and non-forest species were more frequent near rubbing trees compared with controls. These findings are consistent with previous studies on diaspore loads in the coats and hooves of shot wild boars. However, our method allows to identify the transport of diaspores from the open landscape into forest stands where they might especially emerge after disturbance, and a clustered distribution of epizoochorically dispersed seeds. Moreover, accumulation of seeds of wetness indicators near rubbing trees demonstrates directed dispersal of plant species inhabiting wet places between remote wallows.
Das aktuelle Wissen über Prozesse, die zur Fernausbreitung von Pflanzen führen, ist trotz ihrer Bedeutung für das Überleben von Populationen und die Besiedlung neuer potenzieller Habitate noch immer sehr begrenzt. Wildlebende Großsäuger sind heutzutage vermutlich wichtige Vektoren für den Ferntransport von Diasporen innerhalb und zwischen den einzelnen Waldflächen in Mitteleuropa, und speziell das Wildschwein (Sus scrofa L.) spielt dabei offenbar eine herausragende Rolle. Wir nutzen hier ein spezifisches Verhalten des Wildschweins – Suhlen im Schlamm und nachfolgendes Scheuern an sogenannten Malbäumen – um die epizoochore Ausbreitung von Gefäßpflanzen-Diasporen einzuschätzen. Dargestellt werden die Ergebnisse von Samenbank-Untersuchungen von 27 Malbäumen im Vergleich zu 27 Kontrollbäumen aus sieben Waldgebieten in Deutschland. Sowohl die mittlere Zahl lebensfähiger Samen als auch die Artenzahl waren höher in Bodenproben neben Malbäumen. Zehn der 20 in der Samenbank verbreitetsten Pflanzenarten hatten hier ihren Schwerpunkt, und viele Arten kamen ausschließlich in den neben Malbäumen gewonnenen Proben vor. Die große Zahl von Pflanzenarten und Samen – zumindest > 1000 pro Baum – im Boden an Malbäumen lässt sich nur durch die Aktivität der Wildschweine erklären. Mit Haken oder Borsten ausgestattete, d.h. an Epizoochorie angepasste Diasporen waren häufiger, aber auch viele Arten mit unspezialisierten Diasporen kamen ausschließlich in der Samenbank bei Malbäumen vor. Anders als weitgehend an Wald gebundene Pflanzenarten waren solche, die sowohl im Wald und im Offenland vorkommen, sowie nicht im Wald vorkommende Arten häufiger neben Malbäumen als neben Kontrollbäumen. Diese Befunde stimmen mit denen früherer Untersuchungen von Diasporenladungen im Fell und in den Hufen geschossener Wildschweine überein. Unsere Methode erlaubt darüber hinaus aber die Identifizierung des Diasporentransports aus dem Offenland in die Waldbestände, wo sie insbesondere nach Störungen keimen dürften, sowie einer ungleichmäßigen Verteilung epizoochor ausgebreiteter Diasporen. Außerdem zeigt die Akkumulation von Samen von Nässezeigern neben den Malbäumen eine gezielte Ausbreitung nasse Standorte bewohnender Pflanzenarten zwischen entfernt gelegenen Suhlen.

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Cui, Lingfei. « A Likelihood Method to Estimate/Detect Gene Flow and A Distance Method to Estimate Species Trees in the Presence of Gene Flow ». The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1406158261.

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Viktorsson, Arvid, et Illya Kyrychenko. « Spell checker for a Java Application ». Thesis, Karlstads universitet, Institutionen för matematik och datavetenskap (from 2013), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-78054.

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Many text-editor users depend on spellcheckers to correct their typographical errors. The absence of a spellchecker can create a negative experience for the user. In today's advanced technological environment spellchecking is an expected feature. 2Consiliate Business Solutions owns a Java application with a text-editor which does not have a spellchecker. This project aims to investigate and implement available techniques and algorithms for spellcheckers and automated word correction. During implementation, the techniques were tested for their performance and the best solutions were chosen for this project. All the techniques were gathered from earlier written literature on the topic and implemented in Java using default Java libraries. Analysis of the results proves that it is possible to create a complete spellchecker combining available techniques and that the quality of a spellchecker largely depends on a well defined dictionary.

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Thèses sur le sujet « Tree distance »

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