Academic literature on the topic 'Graphes en rubans'

The purpose of this study was to examine the effect of instruction in the use of specific rhythmic nuances on the timings of a musical performance. Volunteer subjects were asked to perform Bach's Suite no. 3 for Violoncello solo, Bouree no. 1, using a computer software program that controlled pitches, amplitude, and all other musical variables. The only aspect of the performance that the operator controlled was the rhythmic onset of each pitch. When the subjects had generated a performance with which they were pleased, they recorded it. Subjects in the experimental group were then given a model of rhythmic variations that represented the aggregate of the rubato variations used by 15 professional cellists in performances of this work. This model was presented visually informs, including a version of the score that had been marked up to indicate incidences of rubato, graphs of these incidences, and a prose synopsis. Subjects were then given time to practice until they believed that they were prepared to make a second recording that incorporated these rhythmic variations. Subjects in the control group repeated the pretest procedures. All note-onset data were analyzed to determine the extent to which subjects imitated the model. Results indicated that both groups' pretests, as well as the control group's posttest, had almost no correlation with the model; while the results of the experimental group's posttest significantly correlated with the rhythmic model.

Dans cette thèse on étudie les liens entre les récurrences topologique et géométrique et les volumes de Masur-Veech des espaces des modules des différentielles quadratiques et Abéliennes. On a choisi de s'intéresser aux graphes en rubans car ils peuvent être utilisé pour calculer les volumes de Masur-Veech. Dans le cas des graphes trivalents on propose une formule de récurrence géométrique, qui a été donnée indépendamment dans "On the Kontsevich geometry of the combinatorial Teichmüller space". On étudie ensuite les graphes en rubans orientés, dans ce cas on propose une décomposition des graphes que l'on a choisi d'appeler "La décomposition acyclique''. Cette décomposition permet de décomposer un graphe en ruban général en une famille de graphes à un sommet. En utilisant ce théorème on peut maintenant calculer les volumes des espaces des modules. On relie ensuite la décomposition acyclique aux opérateurs de "cut and join''. A la fin du mémoire on étudie les dégénérescences de graphes en rubans et on montre que les volumes des espaces des modules admettent un prolongement par continuité
In this thesis we study the relations between topological and geometric recursions and Masur Veech volumes of moduli spaces of quadratic and Abelian differentials. We chose to study ribbon graphs because they can be used to compute these volumes. In the case of trivalent ribbon graphs we give a geometric recursion formula that was also independently found in "On the Kontsevich geometry of the combinatorial Teichmüller space". We also study oriented ribbon graphs, in this case we found decomposition of graphs that we call "The acyclic decomposition''. This decomposition allow to decompose general oriented ribbon graphs into graphs with only one vertex. Using this we are able to compute volumes of their moduli spaces. We relate the acyclic decomposition to cut and joins operators. At the end of the memoir we study degenerations of ribbon graphs and show that volumes of moduli spaces of oriented ribbon graphs admit continuous extensions

Les principaux objectifs de cette thèse sont la fabrication et la caractérisation structurale à haute résolution de nanorubans de graphène à bords atomiquement lisses ainsi que leur intégration dans des composants et l'étude du transport électronique. En premier lieu, nous montrons que des nanorubans de graphène cristallins de largeur inférieure à 100 nm et avec des qualités structurales supérieures l'état de l'art peuvent être découpé par un faisceau électronique focalisé d'énergie modérée en présence d'oxygène. Les caractéristiques des rubans obtenus sont également supérieures à l'approche précédente utilisant la vapeur d'eau. Dans un deuxième temps, la structure des nanorubans est caractérisée jusqu'à l'échelle atomique par microscopie électronique en transmission corrigée des aberrations sphériques. Nous montrons que la cristallinité des nanorubans, tant en leur centre que le long des bords de découpe, est préservée. Les performances de notre approche atteignent l'état de l'art et sa reproductibilité permet de fabriquer des rubans longs de plusieurs centaines de nanomètres mais de largeur aussi fine que 16 nm. Ensuite, nous avons transposé la découpe de nanoruban suspendus à une configuration partiellement suspendue sur substrat SiO2/Si permettant de les intégrer dans des composants adaptés aux mesures de transport électronique à basse température et sous champ magnétique. Le transport électronique dans les rubans contactés de 60 x 300 nm présente un gap et des oscillations en balayage de grille arrière qui sont en accord avec un mécanisme de blocage de Coulomb dans un domaine de taille de l'ordre de la taille du ruban. Si ces résultats montrent la persistance de barrières tunnel, ses bords semblent de qualité suffisante pour ne pas induire de confinement supplémentaire. Au-delà des composants mésoscopiques, notre méthode de fabrication des rubans par gravure électronique sous oxygène ouvre des perspectives dans deux domaines en émergence. Elle est compatible avec l'ultravide et parfaitement adaptée au développement d'une technologie atomique à base de graphène. Une caractérisation de la contamination du graphène ainsi qu'une caractérisation électrique de dispositifs de graphène qui a été fait par microscopie à effet tunnel multisonde en ultra vide. Enfin, les rubans de graphène que nous produisons ont les dimensions et qualités structurales requises pour observer un comportement plasmonique du graphène dans le visible et ainsi interagir avec des structures plasmoniques métalliques. Ce couplage a été examiné en étudiant le signal Raman du graphène au voisinage de colloïdes d'or
The main objectives of this thesis are the fabrication and high-resolution structural characterisation of graphene nanoribbons with atomically smooth edges as well as their device integration and electronic transport study. In first place, we show that crystalline graphene nanoribbons with width under 100 nm and structural properties better than the state of the art can be patterned by a focused electron beam in presence of oxygen. The structural characteristics of the ribbons are also better than the old process using water vapour. Secondly, nanoribbons structure is characterized down to the atomic scale by spherical aberration corrected transmission electron microscopy. We show that the nanoribbons crystallinity, of the centre as well as along the cut edges, is preserved. The performance of our process reaches the state of the art and its reproducibility allows to produce ribbons with length of hundreds of nanometer but as narrow as 16 nm. After that, we have transposed the suspended nanoribbon etching to a partially suspended configuration on a SiO2/Si substrate allowing the integration in devices suitable for electronic transport measurements at low temperature and under magnetic field. The electronic transport in contacted ribbons of 60x300 nm shows a gap and oscillations on backgate scanning measurements that are in agreement with a Coulomb blockade mechanism with dot sizes in the range of the ribbon surface. Even though those results show the persistence of tunnel barriers, the edges quality look good enough to avoid additional confinement. Other than mesoscopic devices, our ribbon fabrication process by electronic beam under oxygen atmosphere opens perspectives in two emergent fields. The process is ultra high vacuum compatible and perfectly adapted to the development of an atomic graphene based technology. A characterisation of contaminants of graphene samples as well as electrical characterisation of graphene devices has been performed in a multiprobe scanning tunnelling microscope in ultra high vacuum. Finally, our graphene nanoribbons have the right dimensions and structural qualities required for the observation of plasmonic behaviour of graphene in visible light and so interact with metallic plasmonic structures. This coupling has been analysed by studying the Raman signal of graphene at the close environment of gold colloids

Esta dissertação tem como principal objetivo a introdução à obra do designer Ruben de Freitas Martins (1929 - 1968), apreendendo a sua trajetória e algumas das principais características criativas de seu trabalho. Ele iniciou sua carreira como artista plástico, derivando-a para o design até atingir a posição de empresário do setor, engajado na divulgação da profissão no Brasil. Nessa condição, durante a década de 60 dirigiu a Forminform, considerado o primeiro escritório de design do país. Na primeira parte da dissertação, com o intuito de analisar de forma eficaz e comparativa o seu trabalho, buscamos investigar e reconstruir a trajetória de Ruben Martins, sua formação profissional e o círculo social com o qual conviveu. Para tanto, foi realizado um levantamento de dados sobre a história e o contexto do designer, incluindo a coleta de matérias jornalísticas, artigos e entrevistas realizadas com personalidades que possuem informações sobre o próprio, como João Carlos Cauduro e Karl Heinz Bergmiller, além da constante pesquisa junto ao Acervo Pessoal de Ruben Martins, recolhido pela família. Na segunda parte, encontra-se a análise detalhada de um de seus principais trabalhos, a marca criada para a Rede de Hotéis Tropical (1967), \"leitura\" esta construída a partir do rebatimento das informações levantadas na primeira parte do trabalho.
This dissertation has as main objective the introduction to the work of designer Ruben de Freitas Martins (1929 - 1968), seizing his career and some key features of his creative work. He began his career as an artist, deriving her to the design to reach the position of manager of the sector, engaged in spreading the profession in Brazil. In this condition, during the 60´s, directed the office Forminform, considered the first design office in the country. In the first part of the dissertation, in order to effectively analyze and compare their work, we investigate and reconstruct the trajectory of Ruben Martins, vocational training and social circle with whom he lived. To that end, we conducted a survey about the history and context of the designer, including collection of news stories, articles and interviews with personalities who have information about him, as João Carlos Cauduro and Karl Heinz Bergmiller, farther the constant search with the Personal Collection of Ruben Martins, picked up by family. The second part is the detailed analysis of one of his major works, the brand created for the Network of Tropical Hotels (1967), the \"reading\" is built from information gathered in the first part of the dissertation.

Les propriétés optoélectroniques de jonctions moléculaires sont étudiées par microscopie à effet tunnel (STM). Premièrement, les structures moléculaires sont synthétisées sur une surface Au(111). Puis, par manipulation, nous soulevons et suspendons une molécule entre la pointe du STM et la surface d’or pour obtenir une jonction moléculaire. En appliquant une tension entre la pointe et l'échantillon, un courant est généré, ce qui conduit à l'excitation de la molécule. Ce processus est médié par des modes de plasmons de surface localisé de la pointe. Finalement, la molécule se désexcite de manière radiative et génère un signal de fluorescence. On utilise cette technique pour étudier deux systèmes moléculaires. Dans le premier, un émetteur (porphyrin) est suspendu dans la jonction grâce à des fils organiques (oligothiophène). Ce type de jonction génère une émission de lumière étroite dont la couleur est contrôlée en sélectionnant la structure chimique de l'émetteur. Le contrôle de la largeur du pic d’émission est obtenu en détachant progressivement l'unité émettrice de la surface. On observe aussi des pics vibroniques décalés vers le rouge qui fournissent une empreinte chimique de l’émetteur, et des pics décalés vers le bleu, signe d’une deséxcitation d’un exciton non-thermalisé. Le deuxième type de jonction est composé de nano-rubans de graphène (GNRs) dont la largeur et la structure de l’arrête sont définis avec une précision atomique. Une fois suspendu dans la jonction, les GNRs qui présentent une terminaison spécifique (terminaison C) montrent un spectre d’émission de lumière avec un pic principal et deux pics vibroniques décalés vers le rouge. Le pic principale est associé à une transition intra-ruban entre un état Tamm localisé et un état delocalisé
This thesis presents a study of the optoelectronic properties of molecular junctions performed by scanning tunneling microscopy (STM). First, the molecular structures are synthesized on a Au(111) surface. Then, by manipulation we lift and suspend a molecule between the tip of the STM and the gold surface, creating a single molecule junction. By applying a voltage bias between the tip and the sample, a current is generated, which leads to the excitation of the molecule. This process is mediated by the localized surface plasmon modes of the tip. Eventually, the molecule de-excites in a radiative way, generating a fluorescence signal. We use this technique to study two different molecular junctions. First, an emitting unit (fused-porphyrin) is suspended in the junction by means of organic linkers (oligothiophene). This type of junction generates a narrow-line emission of light whose color is controlled by selecting the chemical structure of the emitting unit. Moreover, control over the linewidth is obtained by progressively detaching the emitting unit from the surface. Also, we observe red-shifted vibronic features that provide a chemical fingerprint of the emitter, and blue- shifted vibronic features that are a sign of hot-luminescence. For the second type of junctions we use graphene nanoribbons (GNRs) of atomically precise width and edge structure. When lifted in the junction, GNRs with a specific type of termination (C-terminated) exhibit a light emission spectrum with a main peak and two red-shifted vibrational features. The main peak is associated to an intra-ribbon transition between a localized state (Tamm) and a delocalized state

Nous commençons par développer la notion de groupe fondamental d'un champ algébrique, à l'aide de sa catégorie de revêtements étales. Cette définition coïncide avec celle, en termes de schémas simpliciaux, de T. Oda. Nous montrons aussi qu'elle permet de retrouver le groupe fondamental profini de l'orbifold analytique associé puis établissons une suite exacte reliant groupe fondamental géométrique et algébrique d'un champ algébrique sur un corps. Dans un deuxième chapitre, après avoir défini les notions d'espace tangent et de diviseur à croisements normaux dans le cadre des champs algébriques, nous généralisons celle de point base tangentiel, bien connue pour les schémas de carcatéristique nulle, aux champs algébriques en caractéristique quelconque. Dans un troisième chapitre, nous montrons que les strates ouvertes de la stratification de l'espace de modules de courbes stables de genre $g$ à $n$ points marqués peuvent se décrire à l'aide des espaces de modules de courbes lisses de dimension inférieure. Nous expliquons aussi comment un graphe en rubans permet de décrire un point-base tangenciel sur ces espaces de modules. Dans un dernier chapitre, nous détaillons certains liens entre la tour des groupoïdes fondamentaux des espaces de modules de courbes lisses relatifs aux points-bases tangenciels précédemment construits et le groupoïde de Lyubashenko, en y construisant certains chemins (torsion, tressage) et en établissant certaines relations entre ces chemins. Dans deux appendices, nous détaillons les notions de champ algébrique et de 2-catégorie.

Abstract Over the last few years there has been growing interest in graphical models and in particular in those based on directed acyclic graphs as a general framework to describe and infer causal relations (Pearl 1995, 2000; Dawid 2000; Lauritzen 2001). This new graphical approach is related to other approaches to formalize the concept of causality, such as Neyman and Rubin’s potential-response model (Neyman 1935; Rubin 1974; Robins 1986) and path analysis or structural equation models (Wright 1921; Haavelmo 1943). The latter concept has been applied in particular by economists to describe the equilibrium distributions of systems that typically evolve over time.

Mobile laser scanning is the most comprehensive type of engineering surveys for the preparation of information models of highways with adjacent infrastructure. This article presents the author's observations based on the processing of the results of mobile laser scanning of roads of the regional center of the Russian Federation in the summer of 2021 as part of the tender for updating the CSODD (comprehensive scheme organization of road's traffics) for urban roads subordinated to the regional transport committee. The article also provides numerical formulas to use it to estimate the labor costs for conducting and processing scanning results (expressed in man-hours and rubles), which can be used to calculate the preliminary cost of public tenders for conducting and processing the results of mobile laser scanning of public roads. So, for 1000 km of urban roads, the price can range from 59.6 million to 150.1 million rubles in prices for the middle of 2023.

This study investigated the use of multistable perception to modulate steady-state visual evoked potentials (SSVEPs) using a computer graphics program and an LCD monitor. The Rubin’s vase ambiguous image was employed for this purpose. A visual stimulator was developed in C++ using the Open Graphics Library (OpenGL). EEG was measured on the occipital area (Oz) of the subject, and a Brain-Computer Interface (BCI) was developed to control a robot in a virtual reality environment. Commands were recognized using the Multivariate Synchronization Index (MSI) method. The results demonstrate the feasibility of eliciting and modulating SSVEP response. During online evaluation, the subject were able to command a virtual telepresence robot with over 80% accuracy and an Information Transfer Rate (ITR) of 7 bits/min.