Academic literature on the topic 'Projection de graphe'
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Journal articles on the topic "Projection de graphe"
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Mezroui, Yahya. "Projection orthogonale sur le graphe d’une relation linéaire fermé." Transactions of the American Mathematical Society 352, no. 6 (December 15, 1999): 2789–800. http://dx.doi.org/10.1090/s0002-9947-99-02410-1.
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Ledermann, Florian. "Classifying Cartographic Projections Based on Dynamic Analysis of Program Code." Abstracts of the ICA 2 (October 9, 2020): 1. http://dx.doi.org/10.5194/ica-abs-2-38-2020.
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Abstract. Analyzing a given map to identify its projection and other geometrical properties has long been an important aspect of cartographic analysis. If explicit information about the projection used in a particular map is not available, the properties of the cartographic transformation can sometimes be reconstructed from the map image. However, such a process of projection analysis requires significant manual labor and oversight.For digital maps, we usually expect the projection from geographic space to map space to have been calculated by a computer program. Such a program can be expected to contain the implementation of the mathematical rules of the projection and subsequent coordinate transformations such as translation and scaling. The program code, therefore, contains information that would allow an analyst to reliably identify map projections and other geometrical transformations applied to the input data.In the case of interactive online maps, the code generating the map is in fact delivered to the map user and could be used for cartographic analysis. The core idea of our novel method proposed for map analysis is to apply reverse engineering techniques on the code implementing the cartographic transformations in order to retrieve the properties of the applied map projection. However, automatic reasoning about computer code by way of static analysis (analyzing the source code without running it) is provably limited – for example, the code delivered to the map user may contain a whole library of different map projections, of which only a specific one may be actually used at runtime. Instead, we propose a dynamic analysis approach to observe and monitor the operations performed by the code as the program runs, and to retrieve the mathematical operations that have been used to calculate the coordinates of every graphical element on the map.The presented method produces, for every graphical element of the map, a transformation graph consisting of low-level mathematical operations. Cartographic projections can be identified as distinctive patterns in the transformation graph, and can be distinguished in a fully automatic way by matching a set of predefined patterns against a particular graph.Projections vary widely in their arithmetic structure, and therefore by the structure of the corresponding transformation graphs extracted from program code. Some projections can be computed directly using continuous equations involving trigonometric functions. Other projections involve solving nonlinear equations, which need to be solved by approximation. Composite projections use different projections depending on some threshold value. Yet other projections, such as the Robinson projection, define a table of predefined values, between which interpolation is used etc.. In each of these cases, we expect to find the operations corresponding to the mathematical structure of the projection in the transformation graph extracted by the presented method.For verifying the method, we have implemented the patterns of several well-known cartographic projections based on the literature and have used it on the transformation graphs extracted from a variety of sample programs. To ensure a diversity of implementations, we have evaluated programs using different and independent JavaScript implementations of projections, including the open source libraries D3.js, proj4js, Leaflet, OpenLayers, and informal implementations of example programs found online. For these case studies, we could successfully identify many projections based on identifying patterns in the transformation graph in a fully automated, unsupervised manner.In the future, the proposed method may be further developed for many innovative application scenarios, such as building a “cartographic search engine” or constructing novel tools for semi-automatic cartographic analysis and review.
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Dilworth, Stephen J., Denka Kutzarova, and Mikhail I. Ostrovskii. "Lipschitz-free Spaces on Finite Metric Spaces." Canadian Journal of Mathematics 72, no. 3 (February 13, 2019): 774–804. http://dx.doi.org/10.4153/s0008414x19000087.
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AbstractMain results of the paper are as follows:(1) For any finite metric space $M$ the Lipschitz-free space on $M$ contains a large well-complemented subspace that is close to $\ell _{1}^{n}$.(2) Lipschitz-free spaces on large classes of recursively defined sequences of graphs are not uniformly isomorphic to $\ell _{1}^{n}$ of the corresponding dimensions. These classes contain well-known families of diamond graphs and Laakso graphs.Interesting features of our approach are: (a) We consider averages over groups of cycle-preserving bijections of edge sets of graphs that are not necessarily graph automorphisms. (b) In the case of such recursive families of graphs as Laakso graphs, we use the well-known approach of Grünbaum (1960) and Rudin (1962) for estimating projection constants in the case where invariant projections are not unique.
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Bae, Yeolhui, Yugyeom Yi, Jeongmoo Lee, and Sungmo Kang. "Research on Definition of BLL Graphs of Knot Diagrams and its Applications." Korean Science Education Society for the Gifted 14, no. 3 (December 30, 2022): 229–36. http://dx.doi.org/10.29306/jseg.2022.14.3.229.
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This paper is the research on the Knot theory in Topology. A knot is a simple closed curve in ℝ and its projection onto a plane in ℝ is called a knot projection. As the results of this paper we define a BLL(Bidirectional Linear Link) graph for a knot projection which is a bidirectional linear link representing the relations between arcs of a knot projection and obtain some properties of the BLL graphs. We also define an Eulerian cycle of the BLL graph and an Eulerian cycle of a knot projection. As the main results of this paper, we obtain the equivalent conditions of being an alternation knot projection as follows: (1) an out-degree of every vertex of the corresponding BLL graph is 2; (2) the corresponding BLL graph has an Eulerian cycle; (3) the knot projection has an Eulerian cycle. As the subsequent study, using these results of the BLL graphs, we propose the analysis on the BLL graphs for deformation operation obtaining a new alternating knot projection, decision on the tricolorability of a knot projection, and a polynomial of a knot projection.
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Larose, Benoit. "Strongly Projective Graphs." Canadian Journal of Mathematics 54, no. 4 (August 1, 2002): 757–68. http://dx.doi.org/10.4153/cjm-2002-029-7.
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AbstractWe introduce the notion of strongly projective graph, and characterise these graphs in terms of their neighbourhood poset. We describe certain exponential graphs associated to complete graphs and odd cycles. We extend and generalise a result of Greenwell and Lovász [6]: if a connected graph G does not admit a homomorphism to K, where K is an odd cycle or a complete graph on at least 3 vertices, then the graph G × Ks admits, up to automorphisms of K, exactly s homomorphisms to K.
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Kaliszewski, S., Alex Kumjian, John Quigg, and Aidan Sims. "Topological realizations and fundamental groups of higher-rank graphs." Proceedings of the Edinburgh Mathematical Society 59, no. 1 (June 10, 2015): 143–68. http://dx.doi.org/10.1017/s0013091515000061.
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AbstractWe investigate topological realizations of higher-rank graphs. We show that the fundamental group of a higher-rank graph coincides with the fundamental group of its topological realization. We also show that topological realization of higher-rank graphs is a functor and that for each higher-rank graphΛ, this functor determines a category equivalence between the category of coverings ofΛand the category of coverings of its topological realization. We discuss how topological realization relates to two standard constructions fork-graphs: projective limits and crossed products by finitely generated free abelian groups.
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NIKKUNI, RYO. "COMPLETELY DISTINGUISHABLE PROJECTIONS OF SPATIAL GRAPHS." Journal of Knot Theory and Its Ramifications 15, no. 01 (January 2006): 11–19. http://dx.doi.org/10.1142/s0218216506004282.
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A generic immersion of a finite graph into the 2-space with p double points is said to be completely distinguishable if any two of the 2p embeddings of the graph into the 3-space obtained from the immersion by giving over/under information to each double point are not ambient isotopic in the 3-space. We show that only non-trivializable graphs and non-planar graphs have a non-trivial completely distinguishable immersion. We give examples of non-trivial completely distinguishable immersions of several non-trivializable graphs, the complete graph on n vertices and the complete bipartite graph on m + n vertices.
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HUH, YOUNGSIK. "AN ELEMENTARY SET FOR EMBEDDED BOUQUET GRAPHS WITH TWO CYCLES." Journal of Knot Theory and Its Ramifications 20, no. 02 (February 2011): 305–25. http://dx.doi.org/10.1142/s0218216511008796.
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A projection of the bouquet graph B with two cycles is said to be trivial if only trivial embeddings are obtained from the projection. In this paper a finite set of nontrivial embeddings of B is shown to be minimal among those which produce all nontrivial projections of B.
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Filippova, P. A. "Values of the weight system on a family of graphs that are not the intersection graphs of chord diagrams." Sbornik: Mathematics 213, no. 2 (February 1, 2022): 235–67. http://dx.doi.org/10.1070/sm9519.
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Abstract The Chmutov-Lando theorem claims that the value of a weight system (a function on the chord diagrams that satisfies the four-term Vassiliev relations) corresponding to the Lie algebra depends only on the intersection graph of the chord diagram. We compute the values of the weight system at the graphs in several infinite series, which are the joins of a graph with a small number of vertices and a discrete graph. In particular, we calculate these values for a series in which the initial graph is the cycle on five vertices; the graphs in this series, apart from the initial one, are not intersection graphs. We also derive a formula for the generating functions of the projections of graphs equal to the joins of an arbitrary graph and a discrete graph to the subspace of primitive elements of the Hopf algebra of graphs. Using the formula thus obtained, we calculate the values of the weight system at projections of the graphs of the indicated form onto the subspace of primitive elements. Our calculations confirm Lando’s conjecture concerning the values of the weight system at projections onto the subspace of primitives. Bibliography: 17 titles.
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HUH, YOUNGSIK, and KOUKI TANIYAMA. "IDENTIFIABLE PROJECTIONS OF SPATIAL GRAPHS." Journal of Knot Theory and Its Ramifications 13, no. 08 (December 2004): 991–98. http://dx.doi.org/10.1142/s0218216504003640.
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A generic map from a finite graph to the 2-space is called identifiable if any two embeddings of the graph into the 3-space obtained by lifting the map with respect to the natural projection from the 3-space to the 2-space are ambient isotopic in the 3-space. We show that only planar graphs have identifiable maps. We characterize the identifiable maps for some planar graphs.
Dissertations / Theses on the topic "Projection de graphe"
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Taki, Sara. "Anonymisation de données liées en utilisant la confidentialité différentielle." Electronic Thesis or Diss., Bourges, INSA Centre Val de Loire, 2023. http://www.theses.fr/2023ISAB0009.
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Cette thèse étudie le problème de la protection de la vie privée dans le LinkedOpen Data (ou « LOD », en français « web des données ouvertes » ou encore « donnéesliées ouvertes »). Ce travail se situe à l’intersection d’une longue série de travaux sur laconfidentialité des données et le LOD. Notre objectif est d’étudier l’impact des aspectssémantiques sur la publication des données et sur les fuites éventuelles d’information.Nous considérons RDF comme le format de représentation du LOD et la confidentialitédifférentielle (DP) comme le principal critère de protection de la vie privée. La DP a étéinitialement conçue pour définir la confidentialité dans le domaine des bases de donnéesrelationnelle. Elle est basée sur une quantification de la difficulté pour un attaquantd’identifier, en observant le résultat d’un algorithme, quelle base de données parmis unvoisinage a été utilisée pour le produire.Les objectifs de cette thèse sont au nombre de quatre: O1) améliorer la protectiondes données LOD. En particulier, proposer une approache permettant de construire desméchanismes DP utilisables sur RDF ; O2) étudier comment les définitions des voisinagessur les bases de données relationnelles en présence de contraintes de clés étrangères (FK) peuvent être traduites en RDF : O3) proposer de nouvelles définitions de voisinages sur des bases de données relationnelles équivalente à des notions existantes de voisinage sur les graphes (avec une sémantique précise) et O4) proposer un formalisme facilitant laconception et l’implémentation de mécanismes d’anonymisation de données RDF.Concernant O1, nous proposons une nouvelle approche basée sur la projection degraphes pour adapter le concept de DP à RDF. Pour O2, nous déterminons le modèlede protection qui correspond à la traduction de modèles déjà existants pour des basesde données relationnelles sous contraintes FK. Pour O3, nous introduisons le conceptde restrict deletion neighborhood (voisinage d’effacement limité) équivalent envoisinage de type "typed-node" (noeud typé). Nous proposons également une relaxation de la définition permettant de traduite les voisinages "typed-outedge" (arc sortanttypé). Pour O4, nous proposons un langage de transformation de graphes basé sur leconcept de réécriture de graphes, qui sert de fondation pour construire divers mécanismes d’anonymisation sur des graphes attribués.L’ensemble de nos contributions théoriques ont été implémentées par des prototypes"preuve de concept" et ont été évalués sur des jeux de données réels, afin de montrerl’applicabilité de nos travaux à des cas d’usage réelsThis thesis studies the problem of privacy in linked open data (LOD). Thiswork is at the intersection of long lines of work on data privacy and linked open data.Our goal is to study how the presence of semantics impacts the publication of data andpossible data leaks. We consider RDF as the format to represent LOD and DifferentialPrivacy (DP) as the main privacy concept. DP was initially conceived to define privacyin the relational database (RDB) domain and is based on a quantification of the difficultyfor an attacker observing an output to identify which database among a neighborhoodis used to produce it.The objective of this thesis is four-fold: O1) to improve the privacy of LOD. Inparticular, to propose an approach to construct usable DP-mechanisms on RDF; O2) tostudy how neighborhood definitions over RDB in the presence of foreign key (FK) constraints translate to RDF; O3) to propose new neighborhood definitions over relationaldatabase translating into existing graph concepts to ease the design of DP mechanisms;and O4) to support the implementation of sanitization mechanisms for RDF graphs witha rigorous formal foundation.For O1, we propose a novel approach based on graph projection to adapt DP toRDF. For O2, we determine the privacy model resulting from the translation of popularprivacy model over RDB with FK constraints to RDF. For O3, we propose the restrictdeletion neighborhood over RDB with FK constraints whose translation to the RDFgraph world is equivalent to typed-node neighborhood. Moreover, we propose a looserdefinition translating to typed-outedge neighborhood. For O4, we propose a graphtransformation language based on graph rewriting to serve as a basis for constructingvarious sanitization mechanisms on attributed graphs.We support all our theoretical contributions with proof-of-concept prototypes thatimplement our proposals and are evaluated on real datasets to show the applicability ofour work
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Hadjar, Ahmed. "Composition de polyèdres associés aux problèmes d'optimisation combinatoire." Phd thesis, Grenoble INPG, 1996. http://tel.archives-ouvertes.fr/tel-00345405.
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Le polyèdre associé à un problème d'optimisation combinatoire est l'enveloppe convexe des (vecteurs d'incidence des) solutions réalisables de ce problème. De nombreux problèmes d'optimisation combinatoire se formulent comme une maximisation de fonctions linéaires sur les polyèdres qui leurs sont associés. La description du polyèdre par un système d'inéquations linéaires est intimement liée à la résolution du problème correspondant, par le biais de la programmation linéaire. Afin de déterminer un tel système, une approche classique consiste à décomposer le problème en sous-problèmes tels que les polyèdres associés soient connus ; une composition ultérieure de ces derniers conduit à une description du polyèdre associé au problème considéré. L'objet principal de cette thèse est l'étude de la composition des polyèdres. Dans un premier temps, une approche de composition, basée sur la programmation dynamique et les méthodes de projection polyédrale, est étudiée et des résultats généraux sont proposés, permettant ainsi d'unifier des recherches existantes dans ce domaine. Cette approche est, ensuite, appliquée à la composition de polyèdres associés au problème du voyageur de commerce. En seconde partie, considérant le problème du stable, des opérations sur les graphes (composition par identification de sous-graphes de deux graphes donnés, adjonction d'une nouvelle arête) sont traitées. Des résultats polyédraux sont donc donnés, et des conséquences concernant la perfection et la h-perfection des graphes sont montrés
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Phan, Minh-Son. "Contribution à l'estimation de la similarité dans un ensemble de projections tomographiques non-orientées." Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAD041/document.
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La cryo-microscopie électronique est une technique tomographique permettant de reconstituer la structure 3D d’un objet complexe en biologie à partir d’un jeu d’acquisitions. Ces images de l’objet complexe sont appelées les projections et sont acquises sous orientations inconnues. Un des avantages de la cryo-microscopie électronique est l’obtention d’un modèle 3D de très haute résolution de l’objet dans un état naturel. La procédure de reconstruction comporte plusieurs étapes telles que l’alignement, la classification des projections, l’estimation de leurs orientations et le raffinement des projections. Lors de ces étapes, la distance entre deux projections est fréquemment mesurée. Le travail réalisé au cours de cette thèse s’organise autour de la recherche théorique d’une distance entre des projections non-orientées avec comme objectif l’amélioration de la procédure de reconstruction tomographique en cryo-microscopie électronique. La contribution de ce travail de thèse est une méthode permettant d’estimer la différence angulaire entre deux projections dans les cas 2D et 3D. Notre méthode est basée sur la construction d’un graphe de voisinage dont les sommets sont les projections, dont les arêtes relient des projections voisines et sont pondérées par une approximation locale de la différence angulaire. Le calcul de ces poids repose sur les propriétés des moments de projection. Notre méthode est testée sur des images simulées de différentes résolutions et de différents niveaux du bruit. La comparaison avec des autres méthodes d’estimation de la différence angulaire est aussi réaliséeCryo-electron microscopy is a tomographic technique allowing to reconstruct a 3D model of complex structure in biology from a set of acquired images. These images are known as the tomographic projections and are taken at unknown directions. The advantage of the cryo-electron microscopy is the 3D reconstruction at very high resolution. The reconstruction procedure consists of many steps such as projection alignment, projection classification, orientation estimation and projection refinement. During these steps, the distance between two projections is frequently measured. The work in this thesis aims at studying the distances mesured between two unknown-direction projections with the objective of improving the reconstruction result in the cryo-electron microscopy. The contribution of this thesis is the developement of a method for estimating the angular difference between two projections in 2D and 3D. Our method is based on the construction of a neighborhood graph whose vertices are the projections, whose edges link the projection neighbors and are weighted by a local approximation of the angular difference. The calculation of the weights relies on the projection moment properties. The proposed method has been tested on simulated images with different resolutions and at different noise levels. The comparison with others estimation methods of angular difference has been realised
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Sun, Qiang. "A contribution to the theory of (signed) graph homomorphism bound and Hamiltonicity." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS109/document.
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Dans cette thèse, nous etudions deux principaux problèmes de la théorie des graphes: problème d’homomorphisme des graphes planaires (signés) et problème de cycle hamiltonien.Comme une extension du théorème des quatre couleurs, il est conjecturé([80], [41]) que chaque graphe signé cohérent planaire de déséquilibré-maille d+1(d>1) admet un homomorphisme à cube projective signé SPC(d) de dimension d. La question suivant étalés naturelle:Est-ce que SPC(d) une borne optimale de déséquilibré-maille d+1 pour tous les graphes signés cohérente planaire de déséquilibré-maille d+1?Au Chapitre 2, nous prouvons que: si (B,Ω) est un graphe signé cohérente dedéséquilibré-maille d qui borne la classe des graphes signés cohérents planaires de déséquilibré-maille d+1, puis |B| ≥2^{d−1}. Notre résultat montre que si la conjecture ci-dessus est vérifiée, alors le SPC(d) est une borne optimale à la fois en terme du nombre des sommets et du nombre de arêtes.Lorsque d=2k, le problème est équivalent aux problème des graphes:est-ce que PC(2k) une borne optimale de impair-maille 2k+1 pour P_{2k+1} (tous les graphes planaires de impair-maille au moins 2k+1)? Notez que les graphes K_4-mineur libres sont les graphes planaires, est PC(2k) aussi une borne optimale de impair-maille 2k+1 pour tous les graphes K_4-mineur libres de impair-maille 2k+1? La réponse est négative, dans[6], est donné une famille de graphes d’ordre O(k^2) que borne les graphes K_4-mineur libres de impair-maille 2k+1. Est-ce que la borne optimale? Au Chapitre 3, nous prouvons que: si B est un graphe de impair-maille 2k+1 qui borne tous les graphes K_4-mineur libres de impair-maille 2k+1, alors |B|≥(k+1)(k+2)/2. La conjonction de nos résultat et le résultat dans [6] montre que l’ordre O(k^2) est optimal. En outre, si PC(2k) borne P_{2k+1}, PC(2k) borne également P_{2r+1}(r>k).Cependant, dans ce cas, nous croyons qu’un sous-graphe propre de P(2k) serait suffisant à borner P_{2r+1}, alors quel est le sous-graphe optimal de PC2k) qui borne P_{2r+1}? Le premier cas non résolu est k=3 et r= 5. Dans ce cas, Naserasr [81] a conjecturé que le graphe Coxeter borne P_{11}. Au Chapitre 4, nous vérifions cette conjecture pour P_{17}.Au Chapitres 5, 6, nous étudions les problèmes du cycle hamiltonien. Dirac amontré en 1952 que chaque graphe d’ordre n est hamiltonien si tout sommet a un degré au moins n/2. Depuis, de nombreux résultats généralisant le théorème de Dirac sur les degré ont été obtenus. Une approche consiste à construire un cycle hamiltonien à partir d'un ensemble de sommets en contrôlant leur position sur le cycle. Dans cette thèse, nous considérons deux conjectures connexes. La première est la conjecture d'Enomoto: si G est un graphe d’ordre n≥3 et δ(G)≥n/2+1, pour toute paire de sommets x,y dans G, il y a un cycle hamiltonien C de G tel que dist_C(x,y)=n/2.Notez que l’ ́etat de degre de la conjecture de Enomoto est forte. Motivé par cette conjecture, il a prouvé, dans [32], qu’une paire de sommets peut être posé des distances pas plus de n/6 sur un cycle hamiltonien. Dans [33], les cas δ(G)≥(n+k)/2 sont considérés, il a prouvé qu’une paire de sommets à une distance entre 2 à k peut être posé sur un cycle hamiltonien. En outre, Faudree et Li ont proposé une conjecture plus générale: si G est un graphe d’ordre n≥3 et δ(G)≥n/2+1, pour toute paire de sommets x,y dans G et tout entier 2≤k≤n/2, il existe un cycle hamiltonien C de G tel que dist_C(x,y)=k. Utilisant de Regularity Lemma et Blow-up Lemma, au chapitre 5, nous donnons une preuve de la conjeture d'Enomoto conjecture pour les graphes suffisamment grand, et dans le chapitre 6, nous donnons une preuve de la conjecture de Faudree et Li pour les graphe suffisamment grandIn this thesis, we study two main problems in graph theory: homomorphism problem of planar (signed) graphs and Hamiltonian cycle problem.As an extension of the Four-Color Theorem, it is conjectured ([80],[41]) that every planar consistent signed graph of unbalanced-girth d+1(d>1) admits a homomorphism to signed projective cube SPC(d) of dimension d. It is naturally asked that:Is SPC(d) an optimal bound of unbalanced-girth d+1 for all planar consistent signed graphs of unbalanced-girth d+1?In Chapter 2, we prove that: if (B,Ω) is a consistent signed graph of unbalanced-girth d which bounds the class of consistent signed planar graphs of unbalanced-girth d, then |B|≥2^{d-1}. Furthermore,if no subgraph of (B,Ω) bounds the same class, δ(B)≥d, and therefore,|E(B)|≥d·2^{d-2}.Our result shows that if the conjecture above holds, then the SPC(d) is an optimal bound both in terms of number of vertices and number of edges.When d=2k, the problem is equivalent to the homomorphisms of graphs: isPC(2k) an optimal bound of odd-girth 2k+1 for P_{2k+1}(the class of all planar graphs of odd-girth at least 2k+1)? Note that K_4-minor free graphs are planar graphs, is PC(2k) also an optimal bound of odd-girth 2k+1 for all K_4-minor free graphs of odd-girth 2k+1 ? The answer is negative, in [6], a family of graphs of order O(k^2) bounding the K_4-minor free graphs of odd-girth 2k+1 were given. Is this an optimal bound? In Chapter 3, we prove that: if B is a graph of odd-girth 2k+1 which bounds all the K_4-minor free graphs of odd-girth 2k+1,then |B|≥(k+1)(k+2)/2. Our result together with the result in [6] shows that order O(k^2) is optimal.Furthermore, if PC(2k) bounds P_{2k+1},then PC(2k) also bounds P_{2r+1}(r>k). However, in this case we believe that a proper subgraph of PC(2k) would suffice to bound P_{2r+1}, then what’s the optimal subgraph of PC(2k) that bounds P_{2r+1}? The first case of this problem which is not studied is k=3 and r=5. For this case, Naserasr [81] conjectured that the Coxeter graph bounds P_{11} . Supporting this conjecture, in Chapter 4, we prove that the Coxeter graph bounds P_{17}.In Chapter 5,6, we study the Hamiltonian cycle problems. Dirac showed in 1952that every graph of order n is Hamiltonian if any vertex is of degree at least n/2. This result started a new approach to develop sufficient conditions on degrees for a graph to be Hamiltonian. Many results have been obtained in generalization of Dirac’s theorem. In the results to strengthen Dirac’s theorem, there is an interesting research area: to control the placement of a set of vertices on a Hamiltonian cycle such that thesevertices have some certain distances among them on the Hamiltonian cycle.In this thesis, we consider two related conjectures, one is given by Enomoto: if G is a graph of order n≥3, and δ(G)≥n/2+1, then for any pair of vertices x, y in G, there is a Hamiltonian cycle C of G such that dist_C(x, y)=n/2. Motivated by this conjecture, it is proved,in [32],that a pair of vertices are located at distances no more than n/6 on a Hamiltonian cycle. In [33], the cases δ(G) ≥(n+k)/2 are considered, it is proved that a pair of vertices can be located at any given distance from 2 to k on a Hamiltonian cycle. Moreover, Faudree and Li proposed a more general conjecture: if G is a graph of order n≥3, and δ(G)≥n/2+1, then for any pair of vertices x, y in G andany integer 2≤k≤n/2, there is a Hamiltonian cycle C of G such that dist_C(x, y) = k. Using Regularity Lemma and Blow-up Lemma, in Chapter 5, we give a proof ofEnomoto’s conjecture for graphs of sufficiently large order, and in Chapter 6, we give a proof of Faudree and Li’s conjecture for graphs of sufficiently large order
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Douar, Brahim. "Fouille de sous-graphes fréquents à base d'arc consistance." Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20108/document.
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Avec la croissance importante du besoin d'analyser une grande masse de données structurées tels que les composés chimiques, les structures de protéines ou même les réseaux sociaux, la fouille de sous-graphes fréquents est devenue un défi réel en matière de fouille de données. Ceci est étroitement lié à leur nombre exponentiel ainsi qu'à la NP-complétude du problème d'isomorphisme d'un sous-graphe général. Face à cette complexité, et pour gérer cette taille importante de l'espace de recherche, les méthodes classiques de fouille de graphes ont exploré des heuristiques de recherche basées sur le support, le langage de description des exemples (limitation aux chemins, aux arbres, etc.) ou des hypothèses (recherche de sous-arborescence communes, de chemins communs, etc.). Dans le cadre de cette thèse, nous nous basons sur une méthode d'appariement de graphes issue du domaine de la programmation par contraintes, nommée AC-projection, qui a le mérite d'avoir une complexité polynomiale. Nous introduisons des approches de fouille de graphes permettant d'améliorer les approches existantes pour ce problème. En particulier, nous proposons deux algorithmes, FGMAC et AC-miner, permettant de rechercher les sous-graphes fréquents à partir d'une base de graphes. Ces deux algorithmes profitent, différemment, des propriétés fortes intéressantes de l'AC-projection. En effet, l'algorithme FGMAC adopte un parcours en largeur de l'espace de recherche et exploite l'approche par niveau introduite dans Apriori, tandis que l'algorithme AC-miner parcourt l'espace en profondeur par augmentation de motifs, assurant ainsi une meilleure mise à l'échelle pour les grands graphes. Ces deux approches permettent l'extraction d'un type particulier de graphes, il s'agit de celui des sous-graphes AC-réduits fréquents. Dans un premier temps, nous prouvons, théoriquement, que l'espace de recherche de ces sous-graphes est moins important que celui des sous-graphes fréquents à un isomorphisme près. Ensuite, nous menons une série d'expérimentations permettant de prouver que les algorithmes FGMAC et AC-miner sont plus efficients que ceux de l'état de l'art. Au même temps, nous prouvons que les sous-graphes AC-réduits fréquents, en dépit de leur nombre sensiblement réduit, ont le même pouvoir discriminant que les sous-graphes fréquents à un isomorphisme près. Cette étude est menée en se basant sur une évaluation expérimentale de la qualité des sous-graphes AC-réduits fréquents dans un processus de classification supervisée de graphesWith the important growth of requirements to analyze large amount of structured data such as chemical compounds, proteins structures, social networks, to cite but a few, graph mining has become an attractive track and a real challenge in the data mining field. Because of the NP-Completeness of subgraph isomorphism test as well as the huge search space, frequent subgraph miners are exponential in runtime and/or memory use. In order to alleviate the complexity issue, existing subgraph miners have explored techniques based on the minimal support threshold, the description language of the examples (only supporting paths, trees, etc.) or hypothesis (search for shared trees or common paths, etc.). In this thesis, we are using a new projection operator, named AC-projection, which exhibits nice complexity properties as opposed to the graph isomorphism operator. This operator comes from the constraints programming field and has the advantage of a polynomial complexity. We propose two frequent subgraph mining algorithms based on the latter operator. The first one, named FGMAC, follows a breadth-first order to find frequent subgraphs and takes advantage of the well-known Apriori levelwise strategy. The second is a pattern-growth approach that follows a depth-first search space exploration strategy and uses powerful pruning techniques in order to considerably reduce this search space. These two approaches extract a set of particular subgraphs named AC-reduced frequent subgraphs. As a first step, we have studied the search space for discovering such frequent subgraphs and proved that this one is smaller than the search space of frequent isomorphic subgraphs. Then, we carried out experiments in order to prove that FGMAC and AC-miner are more efficient than the state-of-the-art algorithms. In the same time, we have studied the relevance of frequent AC-reduced subgraphs, which are much fewer than isomorphic ones, on classification and we conclude that we can achieve an important performance gain without or with non-significant loss of discovered pattern's quality
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Matignon, Daniel. "Plans projectifs créés par obturation de Dehn : application à l'impossibilité d'obtenir l'espace projectif réel de dimension trois." Aix-Marseille 1, 1996. http://www.theses.fr/1996AIX11024.
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Les principaux resultats de ce travail concernent la possibilite d'obtenir l'espace projectif reel de dimension trois, note p#3, par chirurgie de dehn sur un nud non-trivial de s#3. Nous ramenons le probleme chirurgical a un probleme purement combinatoire. Il s'agit d'etudier les proprietes d'un couple de graphes d'intersection (g, h) provenant respectivement d'un plan projectif minimal (dans p#3) et d'une 2-sphere de niveau prise dans une presentation mince du nud (dans s#3). C. Mca. Gordon et j. Luecke ont utilise une demarche similaire dans la solution au probleme du complement (s#3 jouant le role de p#3). L'existence d'une arete projective nous permet d'utiliser la regle de parite, indispensable dans ce type d'argumentation combinatoire. Nous montrons d'une part que les graphes g et h ne representent pas tous les types, et d'autre part qu'ils ne contiennent pas de grand-cycle. Pour cela, nous utilisons les contraintes topologiques de s#3 et de p#3. Grace a cette etude, nous prouvons le resultat suivant: p#3 n'est pas obtenu par chirurgie de dehn sur un nud s'il a moins de quatre ponts. Nous nous placons ensuite, dans le contexte plus general de la creation d'un plan projectif reel par obturation de dehn. L'espace du nud est substitue par une 3-variete compacte connexe irreductible, avec un bord torique. Nous montrons que si le bord torique contient deux pentes distinctes qui produisent un plan projectif par obturation de dehn, alors elles se coupent essentiellement en un seul point ; par suite il y en a au plus trois en general, et au plus une si la variete est l'espace d'un nud de s#3
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Delhommé, Christian. "Propriétés de projection." Lyon 1, 1995. http://www.theses.fr/1995LYO10159.
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La propriete de projection a ete introduite par ernest corominas pour les ensembles ordonnes : un ensemble ordonne est 2-projectif si les projections sont ses seules operations binaires, croissantes et identiques sur la diagonale. L'objet de cette these est l'etude d'extensions de cette notion, a des operations d'arite superieure (projectivite de hamming finie et projectivite cartesienne infinie) et a des structures plus generales. Notre etude des proprietes de projection de hamming (relatives a des operations regulieres par rapport a chaque argument) est fondee sur des idees de topologie algebrique de base. Nous introduisons divers complexes de chaines, dont les proprietes nous fournissent des criteres de projectivite. Ainsi, nous etablissons par exemple, qu'un graphe fini, connexe, sans sommet pendant, est hamming 2-projectif des qu'il n'a ni triangle ni carre, et plus generalement pour n>2, qu'il est hamming n-projectif, quand il n'a pas cycle de longueur inferieure ou egale a n + 1 et qu'il n'est pas lui-meme un cycle. En particulier, cela fournit les premiers exemples de graphes verifiant la propriete de 3-projection de hamming. Notre point de vue va egalement nous permettre d'introduire les proprietes de n-projection simple et double. Notre approche des proprietes de projection infinies (relatives a des operations infinitaires) est de nature plus ensembliste. Nous montrons en particulier, qu'un graphe projectif de diametre fini est denombrablement projectif, des qu'il n'est pas compact pour les systemes atomiques a un nombre fini d'inconnues. Cette these est partagee en sept chapitres regroupes en trois parties. La premiere est consacree a l'expose de generalites. Nous y etablissons egalement la projectivite de certaines structures homogenes, qui nous permettront d'illustrer la suite de notre propos. Dans une seconde partie, nous mettons en place un cadre algebrique pour l'etude des proprietes de projection de hamming. Dans la troisieme, nous etudions des proprietes de projection infinie, que nous illustrons notamment par les exemples des shift-graphs et des structures homogenes.
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Hansen, Bret. "Graphic Design as Projection." VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/2117.
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I imagined a world where designing is projecting and where the entire design field is called projection. My research into what it means to be a projector culminates in a participatory creative project that embodies concepts of projection taken from a range of disparate subjects.
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Tsukamoto, Tatsuya. "Knot-inevitable projections of planar graphs /." Electronic version of summary, 1999. http://www.wul.waseda.ac.jp/gakui/gaiyo/2870.pdf.
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Luqman, Muhammad Muzzamil. "Fuzzy multilevel graph embedding for recognition, indexing and retrieval of graphic document images." Thesis, Tours, 2012. http://www.theses.fr/2012TOUR4005/document.
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Cette thèse aborde le problème du manque de performance des outils exploitant des représentationsà base de graphes en reconnaissance des formes. Nous proposons de contribuer aux nouvellesméthodes proposant de tirer partie, à la fois, de la richesse des méthodes structurelles et de la rapidité des méthodes de reconnaissance de formes statistiques. Deux principales contributions sontprésentées dans ce manuscrit. La première correspond à la proposition d'une nouvelle méthode deprojection explicite de graphes procédant par analyse multi-facettes des graphes. Cette méthodeeffectue une caractérisation des graphes suivant différents niveaux qui correspondent, selon nous,aux point-clés des représentations à base de graphes. Il s'agit de capturer l'information portéepar un graphe au niveau global, au niveau structure et au niveau local ou élémentaire. Ces informationscapturées sont encapsulés dans un vecteur de caractéristiques numériques employantdes histogrammes flous. La méthode proposée utilise, de plus, un mécanisme d'apprentissage nonsupervisée pour adapter automatiquement ses paramètres en fonction de la base de graphes àtraiter sans nécessité de phase d'apprentissage préalable. La deuxième contribution correspondà la mise en place d'une architecture pour l'indexation de masses de graphes afin de permettre,par la suite, la recherche de sous-graphes présents dans cette base. Cette architecture utilise laméthode précédente de projection explicite de graphes appliquée sur toutes les cliques d'ordre 2pouvant être extraites des graphes présents dans la base à indexer afin de pouvoir les classifier.Cette classification permet de constituer l'index qui sert de base à la description des graphes etdonc à leur indexation en ne nécessitant aucune base d'apprentissage pré-étiquetées. La méthodeproposée est applicable à de nombreux domaines, apportant la souplesse d'un système de requêtepar l'exemple et la granularité des techniques d'extraction ciblée (focused retrieval)This thesis addresses the problem of lack of efficient computational tools for graph based structural pattern recognition approaches and proposes to exploit computational strength of statistical pattern recognition. It has two fold contributions. The first contribution is a new method of explicit graph embedding. The proposed graph embedding method exploits multilevel analysis of graph for extracting graph level information, structural level information and elementary level information from graphs. It embeds this information into a numeric feature vector. The method employs fuzzy overlapping trapezoidal intervals for addressing the noise sensitivity of graph representations and for minimizing the information loss while mapping from continuous graph space to discrete vector space. The method has unsupervised learning abilities and is capable of automatically adapting its parameters to underlying graph dataset. The second contribution is a framework for automatic indexing of graph repositories for graph retrieval and subgraph spotting. This framework exploits explicit graph embedding for representing the cliques of order 2 by numeric feature vectors, together with classification and clustering tools for automatically indexing a graph repository. It does not require a labeled learning set and can be easily deployed to a range of application domains, offering ease of query by example (QBE) and granularity of focused retrieval
Books on the topic "Projection de graphe"
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Hemispherical projection methods in rock mechanics. London: Allen & Unwin, 1985.
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Shepherd, Angela. Australian wine grape production and winery intake: Projections to 2002-03. Canberra: ABARE, 2000.
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Projective graphics: The first album. London: Hertfordshire Press, 2014.
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Ali, Abdalla, and Australian Bureau of Agricultural and Resource Economics., eds. Wine grapes: Projections of wine grape production and winery intake to 1994-95. Canberra: Australian Bureau of Agricultural and Resource Economics, 1992.
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Guriev, T. S. Trimetricheskie proekt͡s︡ii. Moskva: "Nedra", 1992.
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Sal'kov, Nikolay. Descriptive geometry. ru: INFRA-M Academic Publishing LLC., 2022. http://dx.doi.org/10.12737/1874094.
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The textbook contains a complete course on descriptive geometry for architects. It covers the theoretical issues of orthogonal projections, axonometry, perspective and shadow theory in these sections.
It fully meets the requirements of the Federal State Educational Standard of Secondary Vocational Education, approved by the order of the Ministry of Education and Science of the Russian Federation No. 850 dated July 28, 2014.
It is addressed to students of secondary vocational education institutions studying in the specialty 07.02.01 "Architecture". It can be useful for students of other fields of study, as well as teachers of geometric and graphic disciplines.
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Rodin, Esquejo, and Alphona Adrian, eds. Mind the gap: Intimate strangers. Berkeley, Calif: Image Comics, 2012.
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Dunn, Brenda. Les spectacles de lanterne magique et l'armée britannique: Matériel de projection de la garnison de Halifax dans les années 1860. Ottawa, Ont: Patrimoine canadien, Parcs Canada, 1994.
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1624-1683, Guarini Guarino, and Università di Roma. Dipartimento di rilievo, analisi, disegno dell'ambiente e dell'architettura., eds. La scienza della rappresentazione nella concezione di Guarino Guarini. Roma: Gangemi, 2008.
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Shades of Simon Gray. New York: Delacorte Press, 2001.
Find full textBook chapters on the topic "Projection de graphe"
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Falb, Peter. "Projective Algebraic Geometry III: Products, Graphs, Projections." In Methods of Algebraic Geometry in Control Theory: Part II, 173–80. Boston, MA: Birkhäuser Boston, 1999. http://dx.doi.org/10.1007/978-1-4612-1564-6_11.
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Falb, Peter. "Projective Algebraic Geometry III: Products, Graphs, Projections." In Methods of Algebraic Geometry in Control Theory: Part II, 173–80. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-96574-1_10.
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Yarwood, A. "Orthographic Projection." In Work Out Graphic Communication GCSE, 33–49. London: Macmillan Education UK, 1988. http://dx.doi.org/10.1007/978-1-349-10242-6_3.
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van Wyk, Barend Jacobus, Michaël Antonie van Wyk, and Hubert Edward Hanrahan. "Successive Projection Graph Matching." In Lecture Notes in Computer Science, 263–71. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/3-540-70659-3_27.
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Aravind, N. R., and Udit Maniyar. "Planar Projections of Graphs." In Algorithms and Discrete Applied Mathematics, 453–62. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-39219-2_36.
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Bose, Prosenjit, Pedro Ramos, Francisco Gomez, and Godfried Toussaint. "Drawing nice projections of objects in space." In Graph Drawing, 52–63. Berlin, Heidelberg: Springer Berlin Heidelberg, 1996. http://dx.doi.org/10.1007/bfb0021790.
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Husák, Martin, Joseph Khoury, Đorđe Klisura, and Elias Bou-Harb. "On the Provision of Network-Wide Cyber Situational Awareness via Graph-Based Analytics." In Complex Computational Ecosystems, 167–79. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-44355-8_12.
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AbstractIn this paper, we posit how semi-static (i.e., not changing very often) complex computer network-based intelligence using graph-based analytics can become enablers of Cyber Situational Awareness (CSA) (i.e., perception, comprehension, and projection of situations in a cyber environment). A plethora of newly surfaced cyber security researchers have used graph-based analytics to facilitate particular down tasks in dynamic complex cyber environments. This includes graph-, node- and edge-level detection, classification, and others (e.g., credit card fraudulent transactions as an edge classification problem). To the best of our knowledge, very limited efforts have consolidated the outputs of heterogeneous computer network monitoring and reconnaissance tools (e.g., Nmap) in enabling actionable CSA. As such, in this work, we address this literature gap while describing several use cases of graph traversal, graph measures, and subgraph mining in vulnerability and security state assessment, attack projection and mitigation, and device criticality estimation. We highlight the benefits of the graph-based approaches compared to traditional methods. Finally, we postulate open research and application challenges in graph-based analytics for CSA to prompt promising research directions and operational capabilities.
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Dwyer, Tim, and George Robertson. "Layout with Circular and Other Non-linear Constraints Using Procrustes Projection." In Graph Drawing, 393–404. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-11805-0_37.
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Willems, M. "Projection and unification for conceptual graphs." In Conceptual Structures: Applications, Implementation and Theory, 278–92. Berlin, Heidelberg: Springer Berlin Heidelberg, 1995. http://dx.doi.org/10.1007/3-540-60161-9_44.
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de Ridder, H. N., and H. L. Bodlaender. "Graph automorphisms with maximal projection distances." In Fundamentals of Computation Theory, 204–14. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/3-540-48321-7_16.
Full textConference papers on the topic "Projection de graphe"
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Liu, Hanyang, Junwei Han, and Feiping Nie. "Semi-supervised Orthogonal Graph Embedding with Recursive Projections." In Twenty-Sixth International Joint Conference on Artificial Intelligence. California: International Joint Conferences on Artificial Intelligence Organization, 2017. http://dx.doi.org/10.24963/ijcai.2017/321.
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Many graph based semi-supervised dimensionality reduction algorithms utilize the projection matrix to linearly map the data matrix from the original feature space to a lower dimensional representation. But the dimensionality after reduction is inevitably restricted to the number of classes, and the learned non-orthogonal projection matrix usually fails to preserve distances well and balance the weight on different projection direction. This paper proposes a novel dimensionality reduction method, called the semi-supervised orthogonal graph embedding with recursive projections (SOGE). We integrate the manifold smoothness and label fitness as well as the penalization of the linear mapping mismatch, and learn the orthogonal projection on the Stiefel manifold that empirically demonstrates better performance. Moreover, we recursively update the projection matrix in its orthocomplemented space to continuously learn more projection vectors, so as to better control the dimension of reduction. Comprehensive experiment on several benchmarks demonstrates the significant improvement over the existing methods.
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Wilde, D. J. "Two Generalizations of the Isometric Projection in Geometric Design." In ASME 1987 Design Technology Conferences. American Society of Mechanical Engineers, 1987. http://dx.doi.org/10.1115/detc1987-0045.
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Abstract The well-known pictorial drafting technique of isometric drawing is here generalized in two ways, called “isoclinal” and “axial”, or collectively, “symmetric”. Although the isoclinal projection preserves the useful property of foreshortening adjacent edges equally, and the axial projection foreshortens adjacent edges equally, the directions for these projections usually differ from that for isometric projection. Formulas are derived for the isoclinal and axial directions and their foreshortening factors and rotation matrices. Although intended for three-dimensional computer-aided design, the symmetric projections can also be performed on a drawing board with a protractor. Graphic examples involving design of non-rectangular connectors for three skew structural members and adjacent plates in space are presented.
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Lu, Yueheng, Runjia Tian, Ao Li, Xiaoshi Wang, and Garcia del Castillo Lopez Jose Luis. "CubiGraph5K - Organizational Graph Generation for Structured Architectural Floor Plan Dataset." In CAADRIA 2021: Projections. CAADRIA, 2021. http://dx.doi.org/10.52842/conf.caadria.2021.1.081.
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Shekhawat, Krishnendra. "A Graph Theoretic Approach for the Automated Generation of Dimensioned Floorplans." In CAADRIA 2021: Projections. CAADRIA, 2021. http://dx.doi.org/10.52842/conf.caadria.2021.1.141.
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Wan, Hai, Yonghao Luo, Bo Peng, and Wei-Shi Zheng. "Representation Learning for Scene Graph Completion via Jointly Structural and Visual Embedding." 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.2018/132.
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This paper focuses on scene graph completion which aims at predicting new relations between two entities utilizing existing scene graphs and images. By comparing with the well-known knowledge graph, we first identify that each scene graph is associated with an image and each entity of a visual triple in a scene graph is composed of its entity type with attributes and grounded with a bounding box in its corresponding image. We then propose an end-to-end model named Representation Learning via Jointly Structural and Visual Embedding (RLSV) to take advantages of structural and visual information in scene graphs. In RLSV model, we provide a fully-convolutional module to extract the visual embeddings of a visual triple and apply hierarchical projection to combine the structural and visual embeddings of a visual triple. In experiments, we evaluate our model on two scene graph completion tasks: link prediction and visual triple classification, and further analyze by case studies. Experimental results demonstrate that our model outperforms all baselines in both tasks, which justifies the significance of combining structural and visual information for scene graph completion.
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Mathieson, James L., and Joshua D. Summers. "Complexity Metrics for Directional Node-Link System Representations: Theory and Applications." In ASME 2010 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/detc2010-28561.
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This paper presents an approach to defining and quantifying the complexity of systems as represented in mixed (directed and non-directed) bipartite graphs through the presentation of a central example as well as other applications. The approach presented defines nine measurements of different properties of the graph system. These measurements are derived from the representation of the system into a three dimension relational design structure matrix as well as the projections and transformations of this matrix. The metrics generated address dimensional and connective size, shortest path properties, and the decomposability of the system. Finally, a normalization and aggregate approach of these metrics is then given. This aggregation is visualized with spider graphs that facilitate viewing multiple aspects of complexity within a single perspective.
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Eslami, Mohammed, George Zheng, Hamed Eramian, and Georgiy Levchuk. "Deriving cyber use cases from graph projections of cyber data represented as bipartite graphs." In 2017 IEEE International Conference on Big Data (Big Data). IEEE, 2017. http://dx.doi.org/10.1109/bigdata.2017.8258511.
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Horvat, E.-A., and K. A. Zweig. "One-mode Projection of Multiplex Bipartite Graphs." In 2012 International Conference on Advances in Social Networks Analysis and Mining (ASONAM 2012). IEEE, 2012. http://dx.doi.org/10.1109/asonam.2012.101.
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Ahmed, Nesreen, Nick Duffield, and Liangzhen Xia. "Sampling for Approximate Bipartite Network Projection." 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.2018/456.
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Bipartite graphs manifest as a stream of edges that represent transactions, e.g., purchases by retail customers. Recommender systems employ neighborhood-based measures of node similarity, such as the pairwise number of common neighbors (CN) and related metrics. While the number of node pairs that share neighbors is potentially enormous, only a relatively small proportion of them have many common neighbors. This motivates finding a weighted sampling approach to preferentially sample these node pairs. This paper presents a new sampling algorithm that provides a fixed size unbiased estimate of the similarity matrix resulting from a bipartite edge stream projection. The algorithm has two components. First, it maintains a reservoir of sampled bipartite edges with sampling weights that favor selection of high similarity nodes. Second, arriving edges generate a stream of similarity updates, based on their adjacency with the current sample. These updates are aggregated in a second reservoir sample-based stream aggregator to yield the final unbiased estimate. Experiments on real world graphs show that a 10% sample at each stage yields estimates of high similarity edges with weighted relative errors of about 1%.
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Weng, Yulai, Andrew Specian, and Mark Yim. "Low Cost Optical Mechanical System for Human Robot Interaction." In ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-87885.
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This paper presents the design of a low cost system that can be used as a spherical humanoid robot head to display expressive animations for social robotics. The system offers a versatile canvas for Human Robot Interaction (HRI), especially for face to face communication. To maximize flexibility, both in the style and apparent motion of the robot’s head, we exploit the relatively recent availability of low-cost portable projectors in a retro-projected animated face (RAF). The optical mechanical system is comprised of a projector whose light is reflected off a hemispherical mirror and onto a 360 degree section of the spherical head with sufficient resolution and illumination. We derive the forward and inverse mapping relation between the pixel coordinates on the projection plane of the projector, and the outer spherical surface to offer fast graphic generation. Calibration of the system is achieved by controlling three parameters of image translation and scaling, resulting in a specifically devised light cone whose edges are tangential to the hemispherical mirror. Several facial expressions are tested in illuminated indoor environments to show its potential as a modular low cost robot head for HRI.
Reports on the topic "Projection de graphe"
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Beck, D. M., M. J. Scott, S. F. Shindle, B. A. Napier, A. G. Thurman, N. C. Batishko, M. D. Davis, and D. B. Pittenger. Hanford Area 1990 population and 50-year projections. [Appendix contains computer programming for population projections and graphs showing them by grid areas]. Office of Scientific and Technical Information (OSTI), October 1991. http://dx.doi.org/10.2172/5070450.
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Tavella, Pilar, and Andrew Powell. Revelation of Expectations in Latin America (REVELA): Issue 24: September, 2012. Inter-American Development Bank, September 2012. http://dx.doi.org/10.18235/0008079.
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REVELA analyzes market expectations of growth and inflation in Latin American countries. The figures analyzed represent the results of surveys of private sector actors conducted by the central banks of each country according to their own specific methodologies. They do not represent official projections by the IDB or any other official body. RES collects the results of these surveys from central banks on a monthly basis to produce a report and a set of illustrative graphs and tables.
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Salazni, Mariana, and Andrew Powell. Revelation of Expectations in Latin America (REVELA): No. 12 : April, 2008. Inter-American Development Bank, April 2008. http://dx.doi.org/10.18235/0008245.
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REVELA analyzes market expectations of growth and inflation in Latin American countries. The figures analyzed represent the results of surveys of private sector actors conducted by the central banks of each country according to their own specific methodologies. They do not represent official projections by the IDB or any other official body. RES collects the results of these surveys from participating central banks on a monthly basis to produce a report and a set of illustrative graphs and tables. In this April issue, REVELA reports that growth expectations for 2008 on average remained almost unchanged in Latin America at 5.23%. There are six countries with higher expected 2008 growth rates and two with lower expectations than last month's survey. On the other hand, inflation expectations continue to rise; now the expected inflation rate for 2008 is 7.7%, up from last month's 7.6%.
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Salazni, Mariana, and Andrew Powell. Revelation of Expectations in Latin America (REVELA): No. 10 : February, 2008. Inter-American Development Bank, February 2008. http://dx.doi.org/10.18235/0008243.
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REVELA analyzes market expectations of growth and inflation in Latin American countries. The figures analyzed represent the results of surveys of private sector actors conducted by the central banks of each country according to their own specific methodologies. They do not represent official projections by the IDB or any other official body. RES collects the results of these surveys from participating central banks on a monthly basis to produce a report and a set of illustrative graphs and tables. In this February issue, REVELA reports that growth expectations in Latin America for 2008 remain relatively high and stable. The average expected 2008 growth rate for the countries surveyed is now 5.2%. Inflation expectations continue to rise, increasing most significantly in Bolivia, Guatemala, Honduras and Peru. Now the expected inflation rate for 2008 is 7.1%, 0.1% higher than last surveyed.
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Salazni, Mariana, and Andrew Powell. Revelation of Expectations in Latin America (REVELA): No. 9 : January, 2008. Inter-American Development Bank, January 2008. http://dx.doi.org/10.18235/0008260.
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REVELA analyzes market expectations of growth and inflation in Latin American countries. The figures analyzed represent the results of surveys of private sector actors conducted by the central banks of each country according to their own specific methodologies. They do not represent official projections by the IDB or any other official body. RES collects the results of these surveys from participating central banks on a monthly basis to produce a report and a set of illustrative graphs and tables. In this January issue, REVELA reports that growth expectations in Latin America for 2008 were stable or even increased, except in Chile. The average expected 2008 growth rate for the countries surveyed is now 5.21%, higher than December's prediction of 5.03%. Inflation expectations increased in six countries and declined in four. In particular, expected 2008 inflation in Bolivia fell from 14.02% to 12.54%.
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Salazni, Mariana, and Andrew Powell. Revelation of Expectations in Latin America (REVELA): No. 11 : March, 2008. Inter-American Development Bank, March 2008. http://dx.doi.org/10.18235/0008244.
Full textAbstract:
REVELA analyzes market expectations of growth and inflation in Latin American countries. The figures analyzed represent the results of surveys of private sector actors conducted by the central banks of each country according to their own specific methodologies. They do not represent official projections by the IDB or any other official body. RES collects the results of these surveys from participating central banks on a monthly basis to produce a report and a set of illustrative graphs and tables. In this March issue, REVELA reports that although growth expectations in Latin America for 2008 remain almost unchanged at 5.2%, there are six countries with lower expected 2008 growth rates. On the other hand, Inflation expectations continue to rise, now the expected inflation rate for 2008 is 7.6%, 0.54% higher than last month. The most significant increase occurred in Bolivia where the expected inflation rate rose from 12.91% to 16.97%.
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Pinzon, Mauricio, and Arturo Galindo. Revelation of Expectations in Latin America (REVELA): No. 17 : September, 2008. Inter-American Development Bank, September 2008. http://dx.doi.org/10.18235/0008250.
Full textAbstract:
REVELA analyzes market expectations of growth and inflation in Latin American countries. The figures analyzed represent the results of surveys of private sector actors conducted by the central banks of each country according to their own specific methodologies. They do not represent official projections by the IDB or any other official body. RES collects the results of these surveys from participating central banks on a monthly basis to produce a report and a set of illustrative graphs and tables. The September issue of REVELA reports that growth expectations for 2008 are almost unchanged with respect to last month's survey. Now the simple average expected growth rate is 5.29%. However, growth is expected to slow in 2009, to an average of 4.7%, slightly down from last month 4.8% 2009 forecast. On the other hand, the expected inflation rate for 2008 increased from 9.43% to 9.59%. Inflation expectations for 2009 decreased, reaching a simple average of 8.63%.
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Galindo, Arturo, and Mauricio Pinzon. Revelation of Expectations in Latin America (REVELA): No. 23 : March, 2009. Inter-American Development Bank, March 2009. http://dx.doi.org/10.18235/0008255.
Full textAbstract:
REVELA analyzes market expectations of growth and inflation in Latin American countries. The figures analyzed represent the results of surveys of private sector actors conducted by the central banks of each country according to their own specific methodologies. They do not represent official projections by the IDB or any other official body. RES collects the results of these surveys from participating central banks on a monthly basis to produce a report and a set of illustrative graphs and tables. In this March issue, REVELA reports that growth expectations for 2009 decreased with respect to last month's survey. Now the simple average expected growth rate is 1.91%. In the same way, growth is expected to slow in 2010, to an average of 3.29%, down from last month's 3.62% 2010 forecast. On the other hand, the expected inflation rate for 2009 decreased from 7.25% to 6.66%. The simple average of the expected inflation rate for 2010 is 5.99%.
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Salazni, Mariana, Andrew Powell, Mauricio Pinzon, and Arturo Galindo. Revelation of Expectations in Latin America (REVELA): No. 16 : August, 2008. Inter-American Development Bank, August 2008. http://dx.doi.org/10.18235/0008249.
Full textAbstract:
REVELA analyzes market expectations of growth and inflation in Latin American countries. The figures analyzed represent the results of surveys of private sector actors conducted by the central banks of each country according to their own specific methodologies. They do not represent official projections by the IDB or any other official body. RES collects the results of these surveys from participating central banks on a monthly basis to produce a report and a set of illustrative graphs and tables. In this August issue, REVELA reports that growth expectations for 2008 are almost unchanged with respect to last month's survey. Now the simple average expected growth rate is 5.31%. However, growth is expected to slow in 2009, to an average of 4.8%, slightly down from last month 4.9% 2009 forecast. On the other hand, inflation expectations continue to rise; the expected inflation rate for 2008 increased from 8.95% to 9.43%. Inflation expectations for 2009 have also increased, reaching a simple average of 8.4%.
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Pinzon, Mauricio, and Arturo Galindo. Revelation of Expectations in Latin America (REVELA): No. 21 : January, 2009. Inter-American Development Bank, January 2009. http://dx.doi.org/10.18235/0008253.
Full textAbstract:
REVELA analyzes market expectations of growth and inflation in Latin American countries. The figures analyzed represent the results of surveys of private sector actors conducted by the central banks of each country according to their own specific methodologies. They do not represent official projections by the IDB or any other official body. RES collects the results of these surveys from participating central banks on a monthly basis to produce a report and a set of illustrative graphs and tables. In this January issue, REVELA reports that growth expectations for 2009 decreased with respect to last month's survey. Now the simple average expected growth rate is 2.97%. In the same way, growth is expected to slow in 2010, to an average of 3.54%, down from last month's 3.62% 2010 forecast. On the other hand, the expected inflation rate for 2009 decreased from 8.09% to 7.56%. The simple average of the expected inflation rate for 2010 is 5.96%.