1,721,074 research outputs found
Public Transport Priority for Multimodal Urban Traffic Control
Get PDFIn order to improve the travel time of surface public transport vehicles (bus, tramway, etc.), several cities use Urban Traffic Control (UTC) systems enabling to give priority to public transport. This paper reviews these systems. Further on after a debate on their insufficiencies in the global regulation of the urban traffic on a whole network, the paper proposes intermodal regulation strategies, operating on intersection traffic lights to regulate the traffic, favouring the public transport. All these strategies are based on the Linear Quadratic (LQ) optimal control theory, but they are different in their ways of taking into account the public transport in the optimization problem. The simulation tests are carried out in a network of eight intersections and two public transport lines.Fil: Bhouri, Neila. Université Paris Est; FranciaFil: Mayorano, Fernando Javier. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Grupo de Plasmas Densos Magnetizados. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Grupo de Plasmas Densos Magnetizados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lotito, Pablo Andres. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Grupo de Plasmas Densos Magnetizados. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Grupo de Plasmas Densos Magnetizados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Haj Salem, Habib. Université Paris Est; FranciaFil: Lebacque, Jean Patrick. Université Paris Est; Franci
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Modeling of multimodal transportation systems of large networks
No full textL’objectif de ce travail consiste en la modélisation des flux de véhicules d’un grand et dense réseau de transport multimodal. Le travail s’organise en deux parties: un aspect théorique et un aspect développement. L’étude théorique met l’accent sur la façon dont un réseau multimodal peut être modélisé et comment sa performance en termes d’offre peut être optimisée. Pour ce faire, trois études principales sont réalisées: la prévision et la régulation des flux de trafic sur les grands réseaux de surface, la multimodalité véhiculaire dans les grands réseaux de surface prenant en compte les nouvelles formes de mobilité, et enfin l’impact de l’information sur le coût des itinéraires. La partie développement consiste en la conception d’un simulateur de flux de trafic pour réguler le trafic multimodal véhiculaire. Le simulateur développé devrait aider les opérateurs de transport et les collectivités territoriales dans leurs stratégies de gestion des flux de traficThe objective of this work consists on the modeling of traffic flow of a large multimodaltransportation network. The work is organized in two parts: a theoretical study part anda development part. The theoretical study emphasizes on how a multimodal network canbe model and how its performance in terms of supply can be optimized. To do so, threemain studies are discussed: the traffic flow prediction and regulation on large surface net-works, the vehicular multimodality in big surface networks taking into account new forms ofmobility, and finally the impact of the information on the cost of the itineraries. The devel-opment part consists on the conception of a traffic flow simulator to regulate the vehicularmultimodal traffic. The developed simulator should assist transport operators and territorialcommunities in their traffic flow management strategie
Bidimensional traffic flow models.
No full textParallel sessionInternational audience1. Motivation 2. Static assignment 3. Pedestrian models 4. Macroscopic fundamental diagrams 5. Anisotropic model
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Algorithms for optimal guidance of users in road networks
No full textNous nous intéressons dans ce travail au guidage optimal des usagers dans un réseau routier. Plus précisément, nous nous focalisons sur les stratégies adaptatives de guidage avec des garanties en termes de fiabilité des temps de parcours, et en termes de robustesse de ces stratégies. Nous nous basons sur une approche stochastique où des distributions de probabilités sont associées aux temps de parcours sur les liens du réseau. Le guidage est adaptatif et individuel. L'objectif de ce travail de recherche est le développement de stratégies « robustes » de guidage des usagers dans un réseau de transport routier. Une stratégie de guidage d’un nœud origine vers un nœud destination est dite robuste, ici, si elle minimise la détérioration de sa valeur maximale calculée au départ de l’origine, contre d’éventuelles reconfigurations du réseau dues à des coupures de liens (accidents, travaux, etc.) La valeur de la stratégie de guidage est maximisée par rapport à la moyenne et à la fiabilité des temps de parcours associées à la stratégie. Deux principales parties sont distinguées dans ce travail. Nous commençons par l’aspect statique du guidage, où la dynamique du trafic n’est pas prise en compte. Nous proposons une extension d’une approche existante de guidage, pour tenir compte de la robustesse des itinéraires calculés. Dans une deuxième étape, nous combinons notre nouvel algorithme avec un modèle microscopique du trafic pour avoir l’effet de la dynamique du trafic sur le calcul d’itinéraires robustesIn this work, we are interested in the optimal guidance of users on road networks. More precisely, we are focused on the adaptive strategies of guidance with guarantees in terms of the travel time reliability and in terms of the robustness of the strategies. We base here on a stochastic approach, where probability distributions are associated to travel times on the links of the network. The guidance is adaptive and user-based. The objective of this work is the development of "robust" strategies for user guidance in a road network. A guidance strategy is said to be robust, here, if it minimizes the deterioration of its maximum value calculated at the origin, against eventual reconfigurations of the network due to link failures (accidents, works, etc.) The value of a guidance strategy is maximized with respect to the mean travel time and its reliability. Two main parts are distinguished in this work. We start with the static aspect of the guidance, where the traffic dynamics are not taken into account. We propose an extension of an existing guidance approach, to take into account the robustness of the calculated itineraries. In a second step, we combine our new guidance algorithm with a microscopic traffic model in order to have the effect of the traffic dynamics on the robust route calculatio
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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