Academic literature on the topic 'Graphes de mots'
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Journal articles on the topic "Graphes de mots"
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Shukur, Ali A., Akbar Jahanbani, and Haider Shelash. "The Behavior of Weighted Graph’s Orbit and Its Energy." Mathematical Problems in Engineering 2021 (May 17, 2021): 1–6. http://dx.doi.org/10.1155/2021/9933072.
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Studying the orbit of an element in a discrete dynamical system is one of the most important areas in pure and applied mathematics. It is well known that each graph contains a finite (or infinite) number of elements. In this work, we introduce a new analytical phenomenon to the weighted graphs by studying the orbit of their elements. Studying the weighted graph's orbit allows us to have a better understanding to the behaviour of the systems (graphs) during determined time and environment. Moreover, the energy of the graph’s orbit is given.
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Bailblé, Olivier, and Eric Bailblé. "Les nouvelles technologies face à l’historiographie positiviste de l’histoire de France : étude sur le 19ème siècle en français : enjeux et perspectives." Matices en Lenguas Extranjeras, no. 9 (January 1, 2015): 68–90. http://dx.doi.org/10.15446/male.n9.54913.
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Cet article a donné la possibilité de rendre compte d’une analyse lexicale du 19ème siècle français dans l’édition mondiale produite durant les 19ème et 20ème siècles à l’aide d’un nouvel outil lexicométrique nommé « N-gram-Viewer » (visualisateur de fréquence de mots). Cet instrument numérique en ligne sur l’Internet nous a permis de réaliser une approche assez précise des occurrences lexicales des deux derniers siècles. Ce logiciel qui manipule un corpus de 5 millions de livres numérisés est à la fois linguistique et historique. Il offre en effet des possibilités nouvelles pour apprécier et expliquer l’histoire du 19ème siècle français entre mythe et réalité.La problématique centrale de cet article a donc été la suivante : dans quelle mesure peut-on dire que les nouvelles technologies linguistiques permettent d’obtenir un autre re- gard sur l’histoire dite traditionnelle d’un pays ? Et plus avant encore : dans quelle mesure peut-on dire aussi qu’une analyse structurelle macro-lexicale peut débusquer des représen- tations inédites et constitutives gravitant autour des « Grands Hommes » liés naturellement à l’histoire événementielle ou des positivistes d’un pays ?Les données obtenues ont permis de construire des courbes d’occurrences lexicales (nommées N-grammes) qui nous ont donné accès à un monde numérique jusqu’ici caché. Cet outil nous a permis surtout de voir un double immatériel de la mémoire de l’humanité car il offre l’accès à des traitements algorithmiques accélérés et à des enregistrements mas- sifs d’information connectés à l’édition mondiale.La science de fouilles de données (data mining), la science de réseaux (les graphes obtenus par l’Internet) et leur mise à jour par des « datas centers », tels ont été les trois pa- ramètres essentiels de cette recherche. Ces trois aspects techniques ont constitué la toile de fond de cette étude qui dispose au final de plus de 500 milliards de mots, soit environ 5 téraoctets. La création numérique de ce méga-texte réalisé par les laboratoires « Google » et l’université d’Harvard en 2010 a donc ouvert des perspectives inédites entre culture et nu- mérique, d’où le néologisme récent de « Culturomique » pour nommer ce microscope d’analyse linguistique au service de l’histoire.
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Bielak, Halina. "On graphs with restricted link graphs and the chromatic number at most $3$." Časopis pro pěstování matematiky 113, no. 3 (1988): 225–31. http://dx.doi.org/10.21136/cpm.1988.108781.
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Ndjapou, François. "Images&mots." Le sociographe 49, no. 1 (2015): 29. http://dx.doi.org/10.3917/graph.049.0029.
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Monge, Julia. "Des mots en fumées." Le sociographe 39, no. 3 (2012): 46. http://dx.doi.org/10.3917/graph.039.0046.
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Belzeaux, Annick. "Des mots pour le dire." Le sociographe 27, no. 3 (2008): 12. http://dx.doi.org/10.3917/graph.027.0012.
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Portal, Brigitte. "Des mots et des sens." Le sociographe 37, no. 1 (2012): 19. http://dx.doi.org/10.3917/graph.037.0019.
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Abbou, Julie. "(Typo)graphies anarchistes. Où le genre révèle l’espace politique de la langue." Mots, no. 113 (March 9, 2017): 53–72. http://dx.doi.org/10.4000/mots.22637.
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Pasquet, Guy-Noël. "Jouer des jeux de mots du jouet." Le sociographe 41, no. 1 (2013): 4. http://dx.doi.org/10.3917/graph.041.0004.
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Burgy, Caroline, Samia Mahalaine, Manuella Ngnafe, and Teddy Samson. "Des mots aux images, histoire de dire..." Le sociographe N° 57, no. 1 (2017): 85. http://dx.doi.org/10.3917/graph.057.0085.
Full textDissertations / Theses on the topic "Graphes de mots"
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Parshina, Olga. "Structures périodiques en mots morphiques et en colorations de graphes circulants infinis." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1071/document.
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Cette thèse est composée de deux parties : l’une traite des propriétés combinatoires de mots infinis et l’autre des problèmes de colorations des graphes.La première partie du manuscrit concerne les structures régulières dans les mots apériodiques infinis, à savoir les sous-séquences arithmétiques et les premiers retours complets.Nous étudions la fonction qui donne la longueur maximale d’une sous-séquence arithmétique monochromatique (une progression arithmétique) en fonction de la différence commune d pour une famille de mots morphiques uniformes, qui inclut le mot de Thue-Morse. Nous obtenons la limite supérieure explicite du taux de croissance de la fonction et des emplacements des progressions arithmétiques de longueurs maximales et de différences d. Pour étudier des sous-séquences arithmétiques périodiques dans des mots infinis, nous définissons la notion d'indice arithmétique et obtenons des bornes supérieures et inférieures sur le taux de croissance de la fonction donnant l’indice arithmétique dans la même famille de mots.Dans la même veine, une autre question concerne l’étude de deux nouvelles fonctions de complexité de mots infinis basées sur les notions de mots ouverts et fermés. Nous dérivons des formules explicites pour les fonctions de complexité ouverte et fermée pour un mot d'Arnoux-Rauzy sur un alphabet de cardinalité finie.La seconde partie de la thèse traite des colorations parfaites (des partitions équitables) de graphes infinis de degré borné. Nous étudions les graphes de Caley de groupes additifs infinis avec un ensemble de générateurs fixé. Nous considérons le cas où l'ensemble des générateurs est composé d'entiers de l'intervalle [-n, n], et le cas où les générateurs sont des entiers impairs de [-2n-1, 2n+1], où n est un entier positif. Pour les deux familles de graphes, nous obtenons une caractérisation complète des colorations parfaites à deux couleursThe content of the thesis is comprised of two parts: one deals with combinatorial properties of infinite words and the other with graph coloring problems.The first main part of the manuscript concerns regular structures in infinite aperiodic words, such as arithmetic subsequences and complete first returns.We study the function that outputs the maximal length of a monochromatic arithmetic subsequence (an arithmetic progression) as a function of the common difference d for a family of uniform morphic words, which includes the Thue-Morse word. We obtain the explicit upper bound on the rate of growth of the function and locations of arithmetic progressions of maximal lengths and difference d. To study periodic arithmetic subsequences in infinite words we define the notion of an arithmetic index and obtain upper and lower bounds on the rate of growth of the function of arithmetic index in the same family of words.Another topic in this direction involves the study of two new complexity functions of infinite words based on the notions of open and closed words. We derive explicit formulae for the open and closed complexity functions for an Arnoux-Rauzy word over an alphabet of finite cardinality.The second main part of the thesis deals with perfect colorings (a.k.a. equitable partitions) of infinite graphs of bounded degree. We study Caley graphs of infinite additive groups with a prescribed set of generators. We consider the case when the set of generators is composed of integers from the interval [-n,n], and the case when the generators are odd integers from [-2n-1,2n+1], where n is a positive integer. For both families of graphs, we obtain a complete characterization of perfect 2-colorings
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Lestrée, Laurent. "Recherche de mots et d'arbres en parallèle." Paris 7, 1993. http://www.theses.fr/1993PA077074.
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Cette thèse examine les possibilités et les performances de la recherche sur les mots et les arbres en parallèle. La première partie traite de la recherche de mots dans un texte, sur les modèles Pram et hyper cube. Nous présentons un nouvel algorithme qui réalise cette recherche en temps o(log n) sur un hyper cube Simd, montrant qu'il est possible d'atteindre le minima temporel pour ce problème. La seconde partie examine la recherche parallèle de motifs dans les arbres. Nous généralisons des techniques sur les automates d'arbres. Finalement, la dernière partie expose les principes d'un langage fonctionnel parallèle base sur la recherche d'arbres, et elle décrit l'implémentation de ce langage sur la connection machine cm-2
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Vaslet, Elise. "Répétitions dans les mots et seuils d'évitabilité." Thesis, Aix-Marseille 2, 2011. http://www.theses.fr/2011AIX22048/document.
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Nous étudions dans cette thèse différents problèmes d'évitabilité des répétitions dans les mots infinis. Soulevée par Thue et motivée par ses travaux sur les mots sans carrés, la problématique s'est développée au cours du XXe siècle, et est aujourd'hui devenue un des grands domaines de recherche en combinatoire des mots. En 1972, Dejean proposa une importante conjecture, dont la validation étape par étape s'est terminée récemment (2009). La conjecture concerne le seuil des répétitions d'un alphabet, i.e., la borne inférieure des exposants évitables sur cet alphabet. La notion de seuil, comme frontière entre évitabilité et non-évitabilité d'un ensemble donné de mots, est le fil directeur de nos travaux. Nous nous intéressons d'abord à une généralisation du seuil des répétitions (nous donnons des encadrements de sa valeur). Cette notion permet d'ajouter, pour décrire l'ensemble des répétitions à éviter, au paramètre de l'exposant, celui de la longueur des répétitions. Puis, nous étudions des problèmes d'existence de mots dans lesquels, simultanément, certaines répétitions sont interdites et d'autres sont forcées. Nous répondons, pour l'alphabet ternaire, à la question : quels réels sont l'exposant critique d'un mot infini sur un alphabet fixé? Nous introduisons ensuite une notion de haute répétitivité, et établissons une description partielle des couples d'exposants paramètrant une double contrainte de haute répétitivité et d'évitabilité. Pour finir, nous utilisons des résultats et techniques issus de ces problématiques pour résoudre une question de coloration de graphes : nous introduisons un seuil des répétitions, calqué sur celui connu pour les mots, et donnons sa valeur pour deux classes de graphes, les arbres et les graphes de subdivisionsIn this thesis we study various problems on repetition avoidance in infinite words. Raised by Thue and motivated by his work on squarefree words, the topic developed during the 20th century, and has nowadays become a principal area of research in combinatorics on words. In 1972, Dejean proposed an important conjecture whose verification in steps was completed recently (2009). The conjecture concerns the repetition threshold for an alphabet, i.e., the infimum of the avoidable exponents for that alphabet. The notion of threshold as a borderline between avoidability and unavoidability for a given set of words is the guiding line of our work. First, we focus on a generalization of the repetition threshold. This concept allows us to include, in addition to the exponent, the length of the repetitions as a parameter in the description of the set of repetitions to avoid. We obtain various bounds in that respect. We then study existence problems for words in which simultaneously some repetitions are forbidden, and others are forced. For the ternary alphabet, we answer the question: what real numbers are the critical exponent of some infinite word over a given alphabet? Also, we introduce a notion of highly repetitive words and give a partial description of the pairs of exponents which parameterize the existence of words both highly repetitive and repetition-free. Finally, we use results and techniques stemming from those problems to solve a question on graph colouring: we introduce a repetition threshold adapted from the thresholds we know for words, and give its value for two classes of graphs, namely, trees and subdivision graphs
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Kabil, Mustapha. "Enveloppe injective de graphes et de systèmes de transitions et idéaux de mots." Lyon 1, 1992. http://www.theses.fr/1992LYO10149.
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Cette these a pour but de montrer la pertinence du concept d'enveloppe injective dans la description des varietes de retractes absolus. Etant donne un systeme de transition m:=(q,t) sur un alphabet a, la distance entre deux etats x, y est le langage accepte par l'automate a:=(mx,y ayant x pour etat initial et y pour etat final. Nous supposons l'alphabet ordonne et muni d'une involution preservant l'ordre et nous considerons des systemes de transitions qui sont reflexifs et involutifs. Lorsque a est forme de deux lettres a,b et a=b, ces systemes sont ceux associes aux graphes reflexifs non necessairement symetrques et la distance zig-zag introduite par a. Quilliot en 1983. On peut voir les systemes de transitions reflexifs et involutifs comme des espaces metriques dont la distance prend ses valeurs dans l'algebre de heyting constituee des sections finales de a* muni de l'ordre de higman. De meme que, comme l'a montre j. Isbell, les espaces metriques ordinaires ont une enveloppe injective, chaque espace metrique a valeurs dans cette algebre de heyting a egalement une enveloppe injective; en outre celle-ci est un systeme de transition reflexif et involutif. Si dans le cas des espaces ordinaires, l'enveloppe injective d'un espace a deux elements est le segment qui joint ces deux elements, dans notre cas, meme sur l'alphabet a deux lettres, la structure de l'enveloppe injective peut etre tres compliquee. Or ces enveloppes injectives jouent un role important. Elles permettent de construire toutes les enveloppes injectives et ainsi determinent la variete ar#t formee des systemes de transitions qui sont retractes de toutes leurs extensions isometriques, systemes que nous appelons retractes absolus. Elles interviennent egalement dans la description des sous-varietes. Nous inspirant du schema de classification propose par d. Duffus et i. Rival, nous appelons representation d'un espace metrique e sur notre algebre de heyting toute famille (e#i) d'espaces metriques telle que e est retracte du produit e#i et chaque e#i est retracte de e. Nous disons qu'un espace metrique e est irreductible si pour toute representation (e#i) de e, l'espace e est retracte d'un certain e#i. L'espace e est indecomposable (resp. Finiment indecomposable) si pour toute famille (resp. Finie) (e#i) d'espaces metriques, e retracte du produit e#i implique qu'il est retracte de l'un des facteurs. Nous montrons que les irreductibles sont des enveloppes injectives d'espaces a deux elements. Avec une hypothese de finitude sur l'alphabet a, nous montrons que tout retracte absolu a une representation par des irreductibles. Nous montrons egalement que les sous-varietes de ar#t sont en nombre continupotent des que l'alphabet a au moins deux lettres. Pour une section finale f de a*, notons s#f l'enveloppe injective de l'espace a deux elements (x,y) tel que d(x,y)=f. Nous montrons que e est indecomposable (resp. Finiment indecomposable) si et seulement si il est de la forme s#f avec f completement irreductible (resp. Irreductible) dans l'algebre de heyting. Le premier cas revient a dire que f est de la forme a*u ou u est un mot, le second que f=a*j ou j est un ideal de a. Nous decrivons les systemes de transitions associes aux elements completement irreductibles de l'algebre de heyting et nous montrons qu'ils engendrent la variete des retractes absolus. Comme sous produit nous obtenons une description de la variete des graphes reflexifs non necessairement symetriques, semblable a celle obtenue par r. Nowakowski et i. Rival, et independamment par a. Quilliot, dans le cas symetrique. La description des finiment indecomposables fait appel a une description des ideaux de mots sur un alphabet ordonne. Nous montrons que tout ideal de mots est un produit fini d'ideaux de mots sur un alphabet ordonne. Nous montrons que tout ideal de mots est un produit fini d'ideaux de la forme j union le mot vide avec j ideal de a ou de la forme i* avec i section initiale de a si et seulement si l'alphabet est belordonne. Ce resultat avait ete obtenu par p. Jullien 4 dans le cas ou l'alphabet est une antichaine finie
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Dulucq, Serge. "Etude combinatoire de problème d'énumération, d'algorithmique sur les arbres et de codage par les mots." Bordeaux 1, 1987. http://www.theses.fr/1987BOR10579.
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L'etude d'une transformation sur les arbres a permis de determiner la complexite moyenne d'un algorithme distribue d'exclusion mutuelle. En considerant une famille d'arbres binaires croissants, le probleme pose par dullin relatif a l'enumeration de certaines cartes planaires est resolu. Dans une deuxieme partie est etudie le codage par des mots de langages algebriques. L'ensemble de facteurs des suites de sturm sont aussi etudies d'un point de vue algebrique et arithmetique. La derniere partie est situee dans le domaine de la combinatoire enumerative
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Zohoorianazad, Elahe. "Comportement asymptotique des mots aléatoires et des arbres aléatoires, et applications." Nancy 1, 2007. http://www.theses.fr/2007NAN10034.
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Cette thèse est divisée en deux parties. La première partie s’intéresse à l’analyse probabiliste des mots, particulièrement les mots de Lyndon. Nous trouvons la loi limite de la longueur du facteur droit standard d’un mot aléatoire de Lyndon, en considérant d’abord le cas simple des mots aléatoires finis à deux lettres équiprobables, puis le cas des mots aléatoires finis avec des lettres indépendantes tirées d’un alphabet fini ou infini totalement ordonné selon une loi de probabilité générale. Par ailleurs dans ce cas général, nous trouverons la loi jointe asymptotique des longueurs normalisées des facteurs de Lyndon d’un mot aléatoire fini. Nous donnons finalement un coup d’oeil sur la structure des arbres de Lyndon. La deuxième partie étudie, en première place, la distribution limite d’une fonctionnelle additive définie sur les arbres de Cayley. Ensuite, on étudie un nouveau type de modèle de percolation de dimension 1, le modèle de parking avec stratégie de marches aléatoires pour les déplacements des voituresThis thesis is divided in two parts. The first part is interested in the probabilistic analysis on words, especially in what concerns Lyndon words. We find in this part the limit law of the length of the standard right factor of random Lyndon words, first in the simple case of the alphabet of two equiprobable letters, then in the case of the finite random words with independent letters pulled of a totally ordered finite or infinite alphabet, according to a general probability distribution. Moreover in this general case, we shall find the asymptotic joint law of the normalized lengths of the Lyndon factors of a finite word. We finally give in this part, a look on the structure of Lyndon trees. The second part studies first the limit distribution of an additive functional on Cayley trees, then a new type of a one dimensional percolation model that can be seen as the study of cars parking after a random walk
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Bui, Quang Anh. "Vers un système omni-langage de recherche de mots dans des bases de documents écrits homogènes." Thesis, La Rochelle, 2015. http://www.theses.fr/2015LAROS010/document.
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Notre thèse a pour objectif la construction d’un système omni-langage de recherche de mots dans les documents numérisés. Nous nous plaçons dans le contexte où le contenu du document est homogène (ce qui est le cas pour les documents anciens où l’écriture est souvent bien soignée et mono-scripteur) et la connaissance préalable du document (le langage, le scripteur, le type d’écriture, le tampon, etc.) n’est pas connue. Grâce à ce système, l'utilisateur peut composer librement et intuitivement sa requête et il peut rechercher des mots dans des documents homogènes de n’importe quel langage, sans détecter préalablement une occurrence du mot à rechercher. Le point clé du système que nous proposons est les invariants, qui sont les formes les plus fréquentes dans la collection de documents. Pour le requêtage, l’utilisateur pourra créer le mot à rechercher en utilisant les invariants (la composition des requêtes), grâce à une interface visuelle. Pour la recherche des mots, les invariants peuvent servir à construire des signatures structurelles pour représenter les images de mots. Nous présentons dans cette thèse la méthode pour extraire automatiquement les invariants à partir de la collection de documents, la méthode pour évaluer la qualité des invariants ainsi que les applications des invariants à la recherche de mots et à la composition des requêtesThe objective of our thesis is to build an omni-language word retrieval system for scanned documents. We place ourselves in the context where the content of documents is homogenous and the prior knowledge about the document (the language, the writer, the writing style, etc.) is not known. Due to this system, user can freely and intuitively compose his/her query. With the query created by the user, he/she can retrieve words in homogenous documents of any language, without finding an occurrence of the word to search. The key of our proposed system is the invariants, which are writing pieces that frequently appeared in the collection of documents. The invariants can be used in query making process in which the user selects and composes appropriate invariants to make the query. They can be also used as structural descriptor to characterize word images in the retrieval process. We introduce in this thesis our method for automatically extracting invariants from document collection, our evaluation method for evaluating the quality of invariants and invariant’s applications in the query making process as well as in the retrieval process
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Dao, Ngoc Bich. "Réduction de dimension de sac de mots visuels grâce à l’analyse formelle de concepts." Thesis, La Rochelle, 2017. http://www.theses.fr/2017LAROS010/document.
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La réduction des informations redondantes et/ou non-pertinentes dans la description de données est une étape importante dans plusieurs domaines scientifiques comme les statistiques, la vision par ordinateur, la fouille de données ou l’apprentissage automatique. Dans ce manuscrit, nous abordons la réduction de la taille des signatures des images par une méthode issue de l’Analyse Formelle de Concepts (AFC), qui repose sur la structure du treillis des concepts et la théorie des treillis. Les modèles de sac de mots visuels consistent à décrire une image sous forme d’un ensemble de mots visuels obtenus par clustering. La réduction de la taille des signatures des images consiste donc à sélectionner certains de ces mots visuels. Dans cette thèse, nous proposons deux algorithmes de sélection d’attributs (mots visuels) qui sont utilisables pour l’apprentissage supervisé ou non. Le premier algorithme, RedAttSansPerte, ne retient que les attributs qui correspondent aux irréductibles du treillis. En effet, le théorème fondamental de la théorie des treillis garantit que la structure du treillis des concepts est maintenue en ne conservant que les irréductibles. Notre algorithme utilise un graphe d’attributs, le graphe de précédence, où deux attributs sont en relation lorsque les ensembles d’objets à qui ils appartiennent sont inclus l’un dans l’autre. Nous montrons par des expérimentations que la réduction par l’algorithme RedAttsSansPerte permet de diminuer le nombre d’attributs tout en conservant de bonnes performances de classification. Le deuxième algorithme, RedAttsFloue, est une extension de l’algorithme RedAttsSansPerte. Il repose sur une version approximative du graphe de précédence. Il s’agit de supprimer les attributs selon le même principe que l’algorithme précédent, mais en utilisant ce graphe flou. Un seuil de flexibilité élevé du graphe flou entraîne mécaniquement une perte d’information et de ce fait une baisse de performance de la classification. Nous montrons par des expérimentations que la réduction par l’algorithme RedAttsFloue permet de diminuer davantage l’ensemble des attributs sans diminuer de manière significative les performances de classificationIn several scientific fields such as statistics, computer vision and machine learning, redundant and/or irrelevant information reduction in the data description (dimension reduction) is an important step. This process contains two different categories : feature extraction and feature selection, of which feature selection in unsupervised learning is hitherto an open question. In this manuscript, we discussed about feature selection on image datasets using the Formal Concept Analysis (FCA), with focus on lattice structure and lattice theory. The images in a dataset were described as a set of visual words by the bag of visual words model. Two algorithms were proposed in this thesis to select relevant features and they can be used in both unsupervised learning and supervised learning. The first algorithm was the RedAttSansPerte, which based on lattice structure and lattice theory, to ensure its ability to remove redundant features using the precedence graph. The formal definition of precedence graph was given in this thesis. We also demonstrated their properties and the relationship between this graph and the AC-poset. Results from experiments indicated that the RedAttsSansPerte algorithm reduced the size of feature set while maintaining their performance against the evaluation by classification. Secondly, the RedAttsFloue algorithm, an extension of the RedAttsSansPerte algorithm, was also proposed. This extension used the fuzzy precedence graph. The formal definition and the properties of this graph were demonstrated in this manuscript. The RedAttsFloue algorithm removed redundant and irrelevant features while retaining relevant information according to the flexibility threshold of the fuzzy precedence graph. The quality of relevant information was evaluated by the classification. The RedAttsFloue algorithm is suggested to be more robust than the RedAttsSansPerte algorithm in terms of reduction
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Laurence, Grégoire. "Normalisation et Apprentissage de Transductions d'Arbres en Mots." Phd thesis, Université des Sciences et Technologie de Lille - Lille I, 2014. http://tel.archives-ouvertes.fr/tel-01053084.
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Le stockage et la gestion de données sont des questions centrales en infor- matique. La structuration sous forme d'arbres est devenue la norme (XML, JSON). Pour en assurer la pérennité et l'échange efficace des données, il est nécessaire d'identifier de nouveaux mécanismes de transformations automati- sables. Nous nous concentrons sur l'étude de transformations d'arbres en mots représentées par des machines à états finies. Nous définissons les transducteurs séquentiels d'arbres en mots ne pouvant utiliser qu'une et unique fois chaque nœud de l'arbre d'entrée pour décider de la production. En réduisant le problème d'équivalence des transducteurs séquentiels à celui des morphismes appliqués à des grammaires algébriques (Plandowski, 95), nous prouvons qu'il est décidable en temps polynomial. Cette thèse introduit la notion de transducteur travailleur, forme norma- lisée de transducteurs séquentiels, cherchant à produire la sortie le "plus tôt possible" dans la transduction. A l'aide d'un algorithme de normalisation et de minimisation, nous prouvons qu'il existe un représentant canonique, unique transducteur travailleur minimal, pour chaque transduction de notre classe. La décision de l'existence d'un transducteur séquentiel représentant un échantillon, i.e. paires d'entrées et sorties d'une transformation, est prouvée NP-difficile. Nous proposons un algorithme d'apprentissage produisant à par- tir d'un échantillon le transducteur canonique le représentant, ou échouant, le tout en restant polynomial. Cet algorithme se base sur des techniques d'infé- rence grammaticales et sur l'adaptation du théorème de Myhill-Nerode.
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Vandomme, Elise. "Contributions to combinatorics on words in an abelian context and covering problems in graphs." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GRENM010/document.
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Cette dissertation se divise en deux parties, distinctes mais connexes, qui sont le reflet de la cotutelle. Nous étudions et résolvons des problèmes concernant d'une part la combinatoire des mots dans un contexte abélien et d'autre part des problèmes de couverture dans des graphes. Chaque question fait l'objet d'un chapitre. En combinatoire des mots, le premier problème considéré s'intéresse à la régularité des suites au sens défini par Allouche et Shallit. Nous montrons qu'une suite qui satisfait une certaine propriété de symétrie est 2-régulière. Ensuite, nous appliquons ce théorème pour montrer que les fonctions de complexité 2-abélienne du mot de Thue--Morse ainsi que du mot appelé ''period-doubling'' sont 2-régulières. Les calculs et arguments développés dans ces démonstrations s'inscrivent dans un schéma plus général que nous espérons pouvoir utiliser à nouveau pour prouver d'autres résultats de régularité. Le deuxième problème poursuit le développement de la notion de mot de retour abélien introduite par Puzynina et Zamboni. Nous obtenons une caractérisation des mots sturmiens avec un intercepte non nul en termes du cardinal (fini ou non) de l'ensemble des mots de retour abélien par rapport à tous les préfixes. Nous décrivons cet ensemble pour Fibonacci ainsi que pour Thue--Morse (bien que cela ne soit pas un mot sturmien). Nous étudions la relation existante entre la complexité abélienne et le cardinal de cet ensemble. En théorie des graphes, le premier problème considéré traite des codes identifiants dans les graphes. Ces codes ont été introduits par Karpovsky, Chakrabarty et Levitin pour modéliser un problème de détection de défaillance dans des réseaux multiprocesseurs. Le rapport entre la taille optimale d'un code identifiant et la taille optimale du relâchement fractionnaire d'un code identifiant est comprise entre 1 et 2 ln(|V|)+1 où V est l'ensemble des sommets du graphe. Nous nous concentrons sur les graphes sommet-transitifs, car nous pouvons y calculer précisément la solution fractionnaire. Nous exhibons des familles infinies, appelées quadrangles généralisés, de graphes sommet-transitifs pour lesquelles les solutions entière et fractionnaire sont de l'ordre |V|^k avec k dans {1/4, 1/3, 2/5}. Le second problème concerne les (r,a,b)-codes couvrants de la grille infinie déjà étudiés par Axenovich et Puzynina. Nous introduisons la notion de 2-coloriages constants de graphes pondérés et nous les étudions dans le cas de quatre cycles pondérés particuliers. Nous présentons une méthode permettant de lier ces 2-coloriages aux codes couvrants. Enfin, nous déterminons les valeurs exactes des constantes a et b de tout (r,a,b)-code couvrant de la grille infinie avec |a-b|>4. Il s'agit d'une extension d'un théorème d'AxenovichThis dissertation is divided into two (distinct but connected) parts that reflect the joint PhD. We study and we solve several questions regarding on the one hand combinatorics on words in an abelian context and on the other hand covering problems in graphs. Each particular problem is the topic of a chapter. In combinatorics on words, the first problem considered focuses on the 2-regularity of sequences in the sense of Allouche and Shallit. We prove that a sequence satisfying a certain symmetry property is 2-regular. Then we apply this theorem to show that the 2-abelian complexity functions of the Thue--Morse word and the period-doubling word are 2-regular. The computation and arguments leading to these results fit into a quite general scheme that we hope can be used again to prove additional regularity results. The second question concerns the notion of return words up to abelian equivalence, introduced by Puzynina and Zamboni. We obtain a characterization of Sturmian words with non-zero intercept in terms of the finiteness of the set of abelian return words to all prefixes. We describe this set of abelian returns for the Fibonacci word but also for the Thue-Morse word (which is not Sturmian). We investigate the relationship existing between the abelian complexity and the finiteness of this set. In graph theory, the first problem considered deals with identifying codes in graphs. These codes were introduced by Karpovsky, Chakrabarty and Levitin to model fault-diagnosis in multiprocessor systems. The ratio between the optimal size of an identifying code and the optimal size of a fractional relaxation of an identifying code is between 1 and 2 ln(|V|)+1 where V is the vertex set of the graph. We focus on vertex-transitive graphs, since we can compute the exact fractional solution for them. We exhibit infinite families, called generalized quadrangles, of vertex-transitive graphs with integer and fractional identifying codes of order |V|^k with k in {1/4,1/3,2/5}. The second problem concerns (r,a,b)-covering codes of the infinite grid already studied by Axenovich and Puzynina. We introduce the notion of constant 2-labellings of weighted graphs and study them in four particular weighted cycles. We present a method to link these labellings with covering codes. Finally, we determine the precise values of the constants a and b of any (r,a,b)-covering code of the infinite grid with |a-b|>4. This is an extension of a theorem of Axenovich
Books on the topic "Graphes de mots"
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Biville, Frédérique. Graphie et prononciation des mots grecs en latin. Louvain: Société pour l'information grammaticale<, 1987.
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Graphic design: The 50 most influential graphic designers in the world. London: A & C Black Publishers, 2010.
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illustrator, Di Vito Andrea, Rosemann Bill editor, and Basso Mark editor, eds. Galaxy's most wanted. Minneapolis, Minnesota: ABDO Spotlight, 2016.
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Starr, Sadie. Sadie Starr presents Beading graphs plus many wonderful beading patterns, including rosettes: The most comprehensive collection of beading graphs available. Camp Verde, AZ: Shooting Starr, 1994.
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Western Energy and Land Use Team. MOSS user's manual. 8th ed. Denver, Colo: U.S. Department of the Interior, Bureau of Land Management, Division of Advanced Technology, 1985.
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Lust: A collaborative art journal from the world's most creative graphic designers. Beverly, Mass: Rockport Publishers, 2011.
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Sonneborn, Scott. Tiger Moth: Attack of the zom-bees! North Mankato, Minn: Capstone Stone Arch Books, 2013.
Find full textBook chapters on the topic "Graphes de mots"
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Kano, Mikio, Tomoki Yamashita, and Zheng Yan. "Spanning Caterpillars Having at Most k Leaves." In Computational Geometry and Graphs, 95–100. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-45281-9_9.
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Aronoff, Janee, Francine Spiegel, and Pete Walsh. "Web Graphics: Buttons and Interfaces." In Photoshop Elements 2 Most Wanted, 199–219. Berkeley, CA: Apress, 2002. http://dx.doi.org/10.1007/978-1-4302-5119-4_10.
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Rela, Guillermo, Franco Robledo, and Pablo Romero. "Uniformly Most-Reliable Graphs and Antiholes." In Machine Learning, Optimization, and Data Science, 434–44. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-37599-7_36.
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Braun, Tanya, and Ralf Möller. "Lifted Most Probable Explanation." In Graph-Based Representation and Reasoning, 39–54. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-91379-7_4.
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Keszegh, Balázs, János Pach, Dömötör Pálvölgyi, and Géza Tóth. "Drawing Cubic Graphs with at Most Five Slopes." In Graph Drawing, 114–25. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-70904-6_13.
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Gehrke, Marcel, Tanya Braun, and Ralf Möller. "Lifted Temporal Most Probable Explanation." In Graph-Based Representation and Reasoning, 72–85. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-23182-8_6.
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Averbouch, Ilia, Benny Godlin, and Johann A. Makowsky. "A Most General Edge Elimination Polynomial." In Graph-Theoretic Concepts in Computer Science, 31–42. Berlin, Heidelberg: Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-92248-3_4.
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Xiao, Yingzhe, and Huiwen Meng. "A Survey of the Most Acceptable Handle for Express Boxes." In Advances in Graphic Communication, Printing and Packaging, 652–59. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-3663-8_88.
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Chakraborty, Dibyayan, Sandip Das, Mathew C. Francis, and Sagnik Sen. "On Rectangle Intersection Graphs with Stab Number at Most Two." In Algorithms and Discrete Applied Mathematics, 124–37. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-11509-8_11.
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Potočnik, Primož, Pablo Spiga, and Gabriel Verret. "Groups of Order at Most 6,000 Generated by Two Elements, One of Which Is an Involution, and Related Structures." In Symmetries in Graphs, Maps, and Polytopes, 273–86. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-30451-9_14.
Full textConference papers on the topic "Graphes de mots"
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Nikolentzos, Giannis, Polykarpos Meladianos, Stratis Limnios, and Michalis Vazirgiannis. "A Degeneracy Framework for Graph Similarity." In Twenty-Seventh International Joint Conference on Artificial Intelligence {IJCAI-18}. California: International Joint Conferences on Artificial Intelligence Organization, 2018. http://dx.doi.org/10.24963/ijcai.2018/360.
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The problem of accurately measuring the similarity between graphs is at the core of many applications in a variety of disciplines. Most existing methods for graph similarity focus either on local or on global properties of graphs. However, even if graphs seem very similar from a local or a global perspective, they may exhibit different structure at different scales. In this paper, we present a general framework for graph similarity which takes into account structure at multiple different scales. The proposed framework capitalizes on the well-known k-core decomposition of graphs in order to build a hierarchy of nested subgraphs. We apply the framework to derive variants of four graph kernels, namely graphlet kernel, shortest-path kernel, Weisfeiler-Lehman subtree kernel, and pyramid match graph kernel. The framework is not limited to graph kernels, but can be applied to any graph comparison algorithm. The proposed framework is evaluated on several benchmark datasets for graph classification. In most cases, the core-based kernels achieve significant improvements in terms of classification accuracy over the base kernels, while their time complexity remains very attractive.
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Botler, Fábio, Cristina G. Fernandes, and Juan Gutiérrez. "On Tuza's conjecture for graphs with treewidth at most 6." In III Encontro de Teoria da Computação. Sociedade Brasileira de Computação - SBC, 2018. http://dx.doi.org/10.5753/etc.2018.3141.
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Tuza (1981) conjectured that the size τ (G) of a minimum set of edges that meets every triangle of a graph G is at most twice the size ν(G) of a maximum set of edge-disjoint triangles of G. In this paper we verify this conjecture for graphs with treewidth at most 6. In this paper, all graphs considered are simple and the notation and terminology are standard. A triangle transversal of a graph G is a set of edges of G whose deletion results in a triangle-free graph; and a triangle packing of G is a set of edge-disjoint triangles of G. We denote by τ (G) (resp. ν(G)) the size of a minimum triangle transversal (resp. triangle packing) of G. In [Tuza 1981] the following conjecture was posed: Conjecture (Tuza, 1981). For every graph G, we have τ (G) ≤ 2ν(G).
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Antani, Kavit R., Bryan Pearce, Mary E. Kurz, Laine Mears, Kilian Funk, and Maria E. Mayorga. "Manual Precedence Mapping and Application of a Novel Precedence Relationship Learning Technique to Real-World Automotive Assembly Line Balancing." In ASME 2013 International Manufacturing Science and Engineering Conference collocated with the 41st North American Manufacturing Research Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/msec2013-1235.
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An assembly line is a flow-oriented production system where the productive units performing the operations, referred to as stations, are aligned in a serial manner. The work pieces visit stations successively as they are moved along the line usually by some kind of transportation system, e.g., a conveyor belt. An important decision problem, called Assembly Line Balancing Problem (ALBP), arises and has to be solved when (re-) configuring an assembly line. It consists of distributing the total workload for manufacturing any unit of the product to be assembled among the work stations along the line. The assignment of tasks to stations is constrained by task sequence restrictions which can be expressed in a precedence graph. However, most manufacturers usually do not have precedence graphs or if they do, the information on their precedence graphs is inadequate. As a consequence, the elaborate solution procedures for different versions of ALBP developed by more than 50 years of intensive research are often not applicable in practice. Unfortunately, the known approaches for precedence graph generation are not suitable for the conditions in the automotive industry. Therefore, we describe a detailed application of a new graph generation approach first introduced by Klindworth et al. [1] that is based on learning from past feasible production sequences. This technique forms a sufficient precedence graph that guarantees feasible line balances. Experiments indicate that the proposed procedure is able to approximate the real precedence graph sufficiently well to detect nearly optimal solutions even for a real-world automotive assembly line segment with up to 317 tasks. In particular, it seems to be promising to use interviews with experts in a selective manner by analyzing maximum and minimum graphs to identify still assumed relations that are crucial for the graph’s structure. Thus, the new approach seems to be a major step to close the gap between theoretical line balancing research and practice of assembly line planning.
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Aghaei, Sareh, and Anna Fensel. "Finding Similar Entities Across Knowledge Graphs." In 7th International Conference on Advances in Computer Science and Information Technology (ACSTY 2021). AIRCC Publishing Corporation, 2021. http://dx.doi.org/10.5121/csit.2021.110301.
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Finding similar entities among knowledge graphs is an essential research problem for knowledge integration and knowledge graph connection. This paper aims at finding semantically similar entities between two knowledge graphs. This can help end users and search agents more effectively and easily access pertinent information across knowledge graphs. Given a query entity in one knowledge graph, the proposed approach tries to find the most similar entity in another knowledge graph. The main idea is to leverage graph embedding, clustering, regression and sentence embedding. In this approach, RDF2Vec has been employed to generate vector representations of all entities of the second knowledge graph and then the vectors have been clustered based on cosine similarity using K medoids algorithm. Then, an artificial neural network with multilayer perception topology has been used as a regression model to predict the corresponding vector in the second knowledge graph for a given vector from the first knowledge graph. After determining the cluster of the predicated vector, the entities of the detected cluster are ranked through sentence-BERT method and finally the entity with the highest rank is chosen as the most similar one. To evaluate the proposed approach, experiments have been conducted on real-world knowledge graphs. The experimental results demonstrate the effectiveness of the proposed approach.
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Grüttemeier, Niels, and Christian Komusiewicz. "Learning Bayesian Networks Under Sparsity Constraints: A Parameterized Complexity Analysis." In Twenty-Ninth International Joint Conference on Artificial Intelligence and Seventeenth Pacific Rim International Conference on Artificial Intelligence {IJCAI-PRICAI-20}. California: International Joint Conferences on Artificial Intelligence Organization, 2020. http://dx.doi.org/10.24963/ijcai.2020/586.
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We study the problem of learning the structure of an optimal Bayesian network when additional structural constraints are posed on the network or on its moralized graph. More precisely, we consider the constraint that the moralized graph can be transformed to a graph from a sparse graph class Π by at most k vertex deletions. We show that for Π being the graphs with maximum degree 1, an optimal network can be computed in polynomial time when k is constant, extending previous work that gave an algorithm with such a running time for Π being the class of edgeless graphs [Korhonen & Parviainen, NIPS 2015]. We then show that further extensions or improvements are presumably impossible. For example, we show that when Π is the set of graphs in which each component has size at most three, then learning an optimal network is NP-hard even if k=0. Finally, we show that learning an optimal network with at most k edges in the moralized graph presumably is not fixed-parameter tractable with respect to k and that, in contrast, computing an optimal network with at most k arcs can be computed is fixed-parameter tractable in k.
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Wang, Pinghui, Junzhou Zhao, Xiangliang Zhang, Zhenguo Li, Jiefeng Cheng, John C. S. Lui, Don Towsley, Jing Tao, and Xiaohong Guan. "MOSS-5: A Fast Method of Approximating Counts of 5-Node Graphlets in Large Graphs (Extended Abstract)." In 2018 IEEE 34th International Conference on Data Engineering (ICDE). IEEE, 2018. http://dx.doi.org/10.1109/icde.2018.00244.
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Botler, Fábio, and Luiz Hoffmann. "Decomposition of (2k+1)-regular graphs containing special spanning 2k-regular Cayley graphs into paths of length 2k+1." In Encontro de Teoria da Computação. Sociedade Brasileira de Computação - SBC, 2020. http://dx.doi.org/10.5753/etc.2020.11078.
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A Pl-decomposition of a graph G is a set of paths with l edges in G that cover the edge set of G. Favaron, Genest, and Kouider (2010) conjectured that every (2k+1)-regular graph that contains a perfect matching admits a P2k+1-decomposition. They also verified this conjecture for 5-regular graphs without cycles of length 4. In 2015, Botler, Mota, and Wakabayashi extended this result to 5-regular graphs without triangles. In this paper, we verify this conjecture for (2k+1)-regular graphs that contain the k-th power of a spanning cycle; and for 5-regular graphs that contain certain spanning 4-regular Cayley graphs.
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Gao, Jun, and Jianliang Gao. "A Similarity Measurement Method Based on Graph Kernel for Disconnected Graphs." In Twenty-Eighth International Joint Conference on Artificial Intelligence {IJCAI-19}. California: International Joint Conferences on Artificial Intelligence Organization, 2019. http://dx.doi.org/10.24963/ijcai.2019/904.
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Disconnected graphs are very common in the real world. However, most existing methods for graph similarity focus on connected graph. In this paper, we propose an effective approach for measuring the similarity of disconnected graphs. By embedding connected subgraphs with graph kernel, we obtain the feature vectors in low dimensional space. Then, we match the subgraphs and weigh the similarity of matched subgraphs. Finally, an intuitive example shows the feasibility of the method.
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Ding, Huafeng, and Zhen Huang. "Isomorphism Identification of Graphs of Kinematic Chains." In ASME 2007 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/detc2007-34148.
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Isomorphism identification of graphs is one of the most important and challenging problems in the fields of mathematics, computer science and mechanisms. This paper attempts to solve the problem by finding a unique representation of graphs. First, the perimeter loop of a graph is identified from all the loops of the graph obtained through a new algorithm. From the perimeter loop a corresponding perimeter graph is derived, which renders the forms of the graph canonical. Then, by relabelling the perimeter graph, the canonical perimeter graph is obtained, reducing the adjacency matrices of a graph from hundreds of thousands to several or even just one. On the basis of canonical adjacency matrix set, the unique representation of the graph, the characteristic adjacency matrix, is obtained. In such a way, isomorphism identification, sketching, and establishment of the database of common graphs, including the graphs of kinematic chains, all become easy to realize. Computational complexity analysis shows that, in the field of kinematic chains the approach is much more efficient than McKay’s algorithm which is considered the fastest so far. Our algorithm remains efficient even when the links of kinematic chains increase into the thirties.
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Gottstein, Cyprien, Philippe Raipin Parvedy, Michel Hurfin, Thomas Hassan, and Thierry Coupaye. "Inverse Space Filling Curve Partitioning Applied to Wide Area Graphs." In 9th International Conference on Natural Language Processing (NLP 2020). AIRCC Publishing Corporation, 2020. http://dx.doi.org/10.5121/csit.2020.101417.
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The most recent developments in graph partitioning research often consider scale-free graphs. Instead we focus on partitioning geometric graphs using a less usual strategy: Inverse Spacefilling Partitioning (ISP). ISP relies on a space filling curve to partition a graph and was previously applied to graphs essentially generated from Meshes. We extend ISP to apply it to a new context where the targets are now Wide Area Graphs. We provide an extended comparison with two state-of-the-art graph partitioning streaming strategies, namely LDG and FENNEL. We also propose customized metrics to better understand and identify the use cases for which the ISP partitioning solution is best suited. Experimentations show that in favourable contexts, edge-cuts can be drastically reduced, going from more 34% using FENNEL to less than 1% using ISP.
Reports on the topic "Graphes de mots"
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Chaparro, Rodrigo, Maria Netto, Patricio Mansilla, and Daniel Magallon. Energy Savings Insurance: Advances and Opportunities for Funding Small- and Medium-Sized Energy Efficiency and Distributed Generation Projects in Chile. Inter-American Development Bank, December 2020. http://dx.doi.org/10.18235/0002947.
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The Energy Savings Insurance Program seeks to promote investment in energy efficiency and distributed generation in Latin America, primarily through small- and medium-sized enterprises (SMEs). It focuses on developing an innovative scheme of guaranteed energy performance that mitigates project risk and generates investor confidence (ESI Model). The Inter-American Development Bank (IDB) facilitates the development of the ESI Program in alliance with the National Development Banks (NDBs). The ESI Model includes a contract for the supply, installation, and maintenance of equipment for generating a stipulated amount of energy or energy savings over a specific time period; validation by an independent body; insurance coverage that backs the savings or the guaranteed energy generation; and project financing. This paper describes the main attributes of the ESI Model (the contract, the insurance, validation and financing), evaluates market potential and the most attractive technologies, and identifies the priority sectors for implementing projects in Chile. The most promising economic sectors were found to be the hospitality industry, food processing industry, grape growing/wine production, and the fishing industry, and the technologies of electric motors, boilers, air conditioning systems and photovoltaic solar generation. In each of these sectors, estimates were made of financing requirements as well as CO2 emission reductions that could be achieved.
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Brown, Yolanda, Twonia Goyer, and Maragaret Harvey. Heart Failure 30-Day Readmission Frequency, Rates, and HF Classification. University of Tennessee Health Science Center, December 2020. http://dx.doi.org/10.21007/con.dnp.2020.0002.
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30 Day Hospital Readmission Rates, Frequencies, and Heart Failure Classification for Patients with Heart Failure Background Congestive heart failure (CHF) is the leading cause of mortality, morbidity, and disability worldwide among patients. Both the incidence and the prevalence of heart failure are age dependent and are relatively common in individuals 40 years of age and older. CHF is one of the leading causes of inpatient hospitalization readmission in the United States, with readmission rates remaining above the 20% goal within 30 days. The Center for Medicare and Medicaid Services imposes a 3% reimbursement penalty for excessive readmissions including those who are readmitted within 30 days from prior hospitalization for heart failure. Hospitals risk losing millions of dollars due to poor performance. A reduction in CHF readmission rates not only improves healthcare system expenditures, but also patients’ mortality, morbidity, and quality of life. Purpose The purpose of this DNP project is to determine the 30-day hospital readmission rates, frequencies, and heart failure classification for patients with heart failure. Specific aims include comparing computed annual re-admission rates with national average, determine the number of multiple 30-day re-admissions, provide descriptive data for demographic variables, and correlate age and heart failure classification with the number of multiple re-admissions. Methods A retrospective chart review was used to collect hospital admission and study data. The setting occurred in an urban hospital in Memphis, TN. The study was reviewed by the UTHSC Internal Review Board and deemed exempt. The electronic medical records were queried from July 1, 2019 through December 31, 2019 for heart failure ICD-10 codes beginning with the prefix 150 and a report was generated. Data was cleaned such that each patient admitted had only one heart failure ICD-10 code. The total number of heart failure admissions was computed and compared to national average. Using age ranges 40-80, the number of patients re-admitted withing 30 days was computed and descriptive and inferential statistics were computed using Microsoft Excel and R. Results A total of 3524 patients were admitted for heart failure within the six-month time frame. Of those, 297 were re-admitted within 30 days for heart failure exacerbation (8.39%). An annual estimate was computed (16.86%), well below the national average (21%). Of those re-admitted within 30 days, 50 were re-admitted on multiple occasions sequentially, ranging from 2-8 re-admissions. The median age was 60 and 60% male. Due to the skewed distribution (most re-admitted twice), nonparametric statistics were used for correlation. While graphic display of charts suggested a trend for most multiple re-admissions due to diastolic dysfunction and least number due to systolic heart failure, there was no statistically significant correlation between age and number or multiple re-admissions (Spearman rank, p = 0.6208) or number of multiple re-admissions and heart failure classification (Kruskal Wallis, p =0.2553).
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Wells, Aaron, Tracy Christopherson, Gerald Frost, Matthew Macander, Susan Ives, Robert McNown, and Erin Johnson. Ecological land survey and soils inventory for Katmai National Park and Preserve, 2016–2017. National Park Service, September 2021. http://dx.doi.org/10.36967/nrr-2287466.
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This study was conducted to inventory, classify, and map soils and vegetation within the ecosystems of Katmai National Park and Preserve (KATM) using an ecological land survey (ELS) approach. The ecosystem classes identified in the ELS effort were mapped across the park, using an archive of Geo-graphic Information System (GIS) and Remote Sensing (RS) datasets pertaining to land cover, topography, surficial geology, and glacial history. The description and mapping of the landform-vegetation-soil relationships identified in the ELS work provides tools to support the design and implementation of future field- and RS-based studies, facilitates further analysis and contextualization of existing data, and will help inform natural resource management decisions. We collected information on the geomorphic, topographic, hydrologic, pedologic, and vegetation characteristics of ecosystems using a dataset of 724 field plots, of which 407 were sampled by ABR, Inc.—Environmental Research and Services (ABR) staff in 2016–2017, and 317 were from existing, ancillary datasets. ABR field plots were located along transects that were selected using a gradient-direct sampling scheme (Austin and Heligers 1989) to collect data for the range of ecological conditions present within KATM, and to provide the data needed to interpret ecosystem and soils development. The field plot dataset encompassed all of the major environmental gradients and landscape histories present in KATM. Individual state-factors (e.g., soil pH, slope aspect) and other ecosystem components (e.g., geomorphic unit, vegetation species composition and structure) were measured or categorized using standard classification systems developed for Alaska. We described and analyzed the hierarchical relationships among the ecosystem components to classify 92 Plot Ecotypes (local-scale ecosystems) that best partitioned the variation in soils, vegetation, and disturbance properties observed at the field plots. From the 92 Plot Ecotypes, we developed classifications of Map Ecotypes and Disturbance Landscapes that could be mapped across the park. Additionally, using an existing surficial geology map for KATM, we developed a map of Generalized Soil Texture by aggregating similar surficial geology classes into a reduced set of classes representing the predominant soil textures in each. We then intersected the Ecotype map with the General-ized Soil Texture Map in a GIS and aggregated combinations of Map Ecotypes with similar soils to derive and map Soil Landscapes and Soil Great Groups. The classification of Great Groups captures information on the soil as a whole, as opposed to the subgroup classification which focuses on the properties of specific horizons (Soil Survey Staff 1999). Of the 724 plots included in the Ecotype analysis, sufficient soils data for classifying soil subgroups was available for 467 plots. Soils from 8 orders of soil taxonomy were encountered during the field sampling: Alfisols (<1% of the mapped area), Andisols (3%), Entisols (45%), Gelisols (<1%), Histosols (12%), Inceptisols (22%), Mollisols (<1%), and Spodosols (16%). Within these 8 Soil Orders, field plots corresponded to a total of 74 Soil Subgroups, the most common of which were Typic Cryaquents, Typic Cryorthents, Histic Cryaquepts, Vitrandic Cryorthents, and Typic Cryofluvents.
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Financial Stability Report - First Semester of 2020. Banco de la República de Colombia, March 2021. http://dx.doi.org/10.32468/rept-estab-fin.1sem.eng-2020.
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In the face of the multiple shocks currently experienced by the domestic economy (resulting from the drop in oil prices and the appearance of a global pandemic), the Colombian financial system is in a position of sound solvency and adequate liquidity. At the same time, credit quality has been recovering and the exposure of credit institutions to firms with currency mismatches has declined relative to previous episodes of sudden drops in oil prices. These trends are reflected in the recent fading of red and blue tonalities in the performance and credit risk segments of the risk heatmaps in Graphs A and B.1 Naturally, the sudden, unanticipated change in macroeconomic conditions has caused the appearance of vulnerabilities for short-term financial stability. These vulnerabilities require close and continuous monitoring on the part of economic authorities. The main vulnerability is the response of credit and credit risk to a potential, temporarily extreme macroeconomic situation in the context of: (i) recently increased exposure of some banks to household sector, and (ii) reductions in net interest income that have led to a decline in the profitability of the banking business in the recent past. Furthermore, as a consequence of greater uncertainty and risk aversion, occasional problems may arise in the distribution of liquidity between agents and financial markets. With regards to local markets, spikes have been registered in the volatility of public and private fixed income securities in recent weeks that are consistent with the behavior of the international markets and have had a significant impact on the liquidity of those instruments (red portions in the most recent past of some market risk items on the map in Graph A). In order to adopt a forward-looking approach to those vulnerabilities, this Report presents a stress test that evaluates the resilience of credit institutions in the event of a hypothetical scenario thatseeks to simulate an extreme version of current macroeconomic conditions. The scenario assumes a hypothetical negative growth that is temporarily strong but recovers going into the middle of the coming year and has extreme effects on credit quality. The results suggest that credit institutions have the ability to withstand a significant deterioration in economic conditions in the short term. Even though there could be a strong impact on credit, liquidity, and profitability under the scenario being considered, aggregate capital ratios would probably remain at above their regulatory limits over the horizon of a year. In this context, the recent measures taken by both Banco de la República and the Office of the Financial Superintendent of Colombia that are intended to help preserve the financial stability of the Colombian economy become highly relevant. In compliance with its constitutional objectives and in coordination with the financial system’s security network, Banco de la República will continue to closely monitor the outlook for financial stability at this juncture and will make the decisions that are necessary to ensure the proper functioning of the economy, facilitate the flow of sufficient credit and liquidity resources, and further the smooth functioning of the payment system. Juan José Echavarría Governor
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Monetary Policy Report - October 2020. Banco de la República de Colombia, February 2021. http://dx.doi.org/10.32468/inf-pol-mont-eng.tr4.-2020.
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Recent data suggest that the technical staff’s appraisals of the condition and development of economic activity, inflation and the labor market have been in line with current trends, marked by a decline in demand and the persistence of ample excess productive capacity. A significant projected fall in output materialized in the second quarter, contributing to a decline in inflation below the 3% target and reflected in a significant deterioration of the labor market. A slow recovery in output and employment is expected to continue for the remainder of 2020 and into next year, alongside growing inflation that should remain below the target. The Colombian economy is likely to undergo a significant recession in 2020 (GDP contraction of 7.6%), though this may be less severe than projected in the previous report (-8.5%). Output is expected to have begun a slow recovery in the second half of this year, though it is not projected to return to pre-pandemic levels in 2021 amid significant global uncertainty. The output decline in the first half of 2020 was less severe than anticipated, thanks to an upward revision in first-quarter GDP and a smaller contraction in the second quarter (-15.5%) than had been projected (-16.5%). Available economic indicators suggest an annual decline in GDP in the third quarter of around 9%. No significant acceleration of COVID-19 cases that would imply a tightening of social distancing measures is presumed for the remainder of this year or in 2021. In that context, a gradual opening of the economy would be expected to continue, with supply in sectors that have been most affected by the pandemic recovering slowly as restrictions on economic activity continue to be relaxed. On the spending side, an improvement in consumer confidence, suppressed demand for goods and services, low interest rates, and higher expected levels of foreign demand should contribute to a recovery in output. A low base of comparison would also help explain the expected increase in GDP in 2021. Based on the conditions laid out above, economic growth in 2020 is expected to be between -9% and -6.5%, with a central value of -7.6%. Growth in 2021 is projected to be between 3% and 7%, with a central value of 4.6% (Graph 1.1). Upward revisions compared to the July report take into account a lower-than-expected fall in first-semester growth and a somewhat faster recovery in the third quarter in some sectors. The forecast intervals for 2020 and 2021 growth tightened somewhat but continue to reflect a high degree of uncertainty over theevolution of the pandemic, the easures required to deal with it, and their effects on global and domestic economic activity.
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Monetary Policy Report - January 2021. Banco de la República de Colombia, March 2021. http://dx.doi.org/10.32468/inf-pol-mont-eng.tr1.-2021.
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Macroeconomic Summary Overall inflation (1.61%) and core inflation (excluding food and regulated items) (1.11%) both declined beyond the technical staff’s expectations in the fourth quarter of 2020. Year-end 2021 forecasts for both indicators were revised downward to 2.3% and 2.1%, respectively. Market inflation expectations also fell over this period and suggested inflation below the 3% target through the end of this year, rising to the target in 2022. Downward pressure on inflation was more significant in the fourth quarter than previously projected, indicating weak demand. Annual deceleration among the main groups of the consumer price index (CPI) was generalized and, except for foods, was greater than projected in the October report. The CPI for goods (excluding foods and regulated items) and the CPI for regulated items were subject to the largest decelerations and forecasting discrepancies. In the first case, this was due in part to a greater-than-expected effect on prices from the government’s “VAT-fee day” amid weak demand, and from the extension of some price relief measures. For regulated items, the deceleration was caused in part by unanticipated declines in some utility prices. Annual change in the CPI for services continued to decline as a result of the performance of those services that were not subject to price relief measures, in particular. Although some of the overall decline in inflation is expected to be temporary and reverse course in the second quarter of 2021, various sources of downward pressure on inflation have become more acute and will likely remain into next year. These include ample excesses in capacity, as suggested by the continued and greater-than-expected deceleration in core inflation indicators and in the CPI for services excluding price relief measures. This dynamic is also suggested by the minimal transmission of accumulated depreciation of the peso on domestic prices. Although excess capacity should fall in 2021, the decline will likely be slower than projected in the October report amid additional restrictions on mobility due to a recent acceleration of growth in COVID-19 cases. An additional factor is that low inflation registered at the end of 2020 will likely be reflected in low price adjustments on certain indexed services with significant weight in the CPI, including real estate rentals and some utilities. These factors should keep inflation below the target and lower than estimates from the previous report on the forecast horizon. Inflation is expected to continue to decline to levels near 1% in March, later increasing to 2.3% at the end of 2021 and 2.7% at year-end 2022 (Graph 1.1). According to the Bank’s most recent survey, market analysts expect inflation of 2.7% and 3.1% in December 2021 and 2022, respectively. Expected inflation derived from government bonds was 2% for year-end 2021, while expected inflation based on bonds one year forward from that date (FBEI 1-1 2022) was 3.2%.