Добірка наукової літератури з теми "Affectation du trafic"

This research evaluated the effect of pruning, fertilization and pesticide injection on crown dieback in urban trees in Colombia and analyzed the factors involved. Systemic insecticides and/or fungicides were applied through injections in the trunk of 15 tree species affected by the progressive deterioration of the crown in the urban forests of the Metropolitan Area of the Aburrá Valley. The presence of progressive deterioration was evaluated qualitatively on a scale from zero to three in an average sample of 12 individuals for each species. Two treatments were used: i) application of insecticide + fungicide, and ii) application of insecticide, both treatments were applied three times, plus a general treatment of pruning and fertilization. Also, two controls were evaluated: healthy trees and diseased trees without treatment. The probability of individual progressive deterioration (PD) during the study period according to the species, treatment applied, and the initial state of affectation was estimated using a generalized linear mixed model. The analysis of factors involved also included planting site, traffic flow of the site, the wood density of the species, and time. The results suggest that the deterioration is a dynamic phenomenon associated with environmental stresses caused mainly by the climatic variability. From the evaluated variables, the species seems to be the most determinant factor for the affectation, since intrinsic variables of the species, like wood density, can favor its appearance. On the contrary, the treatments evaluated did not affect the recovery of the species. The action of insects and pathogens seems to be opportunistic once trees are affected.

Highlights two works being carried out by the French Laboratoire Central des Ponts et Chaussées in the field of smart sensors. The first concerns the knowledge of loads applied to bridges in order to evaluate extreme load effects and fatigue load effects over their lifetime. To achieve these goals, a data acquisition system based on smart sensors extracting and classifying extrema in the traffic loads signal has been developed. The second concerns distributed systems software cost reduction by means of a generic model. The aim of the model is the design of a software generator for smart sensor‐based systems. The key of the system is in the description of an instrumentation plan under the form of a data dependence graph (DDG). The goal of the generator is to map and “execute” that DDG on the physical architecture according to the number of transducers, their affectation to the smart sensors and a PC‐based system controller.

Habitat fragmentation is considered a main cause of the global biodiversity crisis. Particularly, the presence of linear transport infrastructures is one of the main causes of habitat fragmentation and its effects represent a threat to the diversity and richness of habitats and to the dispersal capacity of species. This study assesses the state of fragmentation of Natura 2000 habitats (LIC and ZEPA) on Mallorca (Balearic Islands) and analyses its relationship with the presence of road infrastructures, through application of different physiographic and morphometric indicators. The analysis shows a higher degree of fragmentation in the Natura 2000 habitats located in north of Mallorca and the western sector of the Tramuntana mountain range. Those are also more vulnerable to external disturbance, due to a higher proportion of edge habitat in relation to interior habitat. The average use of roads that intersect with protected areas is 5500 vehicles per day. However, the main affectations caused by traffic are concentrated in specific sectors of the Tramuntana range and in the north of the island (Pollença bay, Alcúdia bay and Artá) where the average use is higher than 10,000 vehicles per day.

The purpose of the article is to examine John Donneʼs poems “An Anatomy of the World: The First Anniversary” and “Of the Progress of the Soul: The Second Anniversary” as a part of the Petrarchan poetic tradition. In order to accomplish this purpose, we have applied a complex approach by using elements of biographical, genealogical, typological, hermeneutic, comparative and structural-semiotic methods of literary analysis. The article analyzes scientific investigations devoted to the issue of the Petrarchan impulses in “The First” and “The Second Anniversary”. The circumstances and history of their creation have been disclosed, their dominant problems have been highlighted, and their direct connection with the poetic practice of European Petrarchism has been emphasized. It has been noted that the initial idea of the writer – to connect the decay and decline of the world with the death of an innocent young girl – was not new. He often used the theme of death and in such poems as, for example, “A Fever” and “A Nocturnal upon Saint Lucyʼs Day”, the death of the heroine was associated with catastrophic, sometimes even global consequences for the natural world and society. And this is not surprising, because at the center of John Donneʼs universe and the microcosm of his lyrical hero, there has always been a woman – the basis and determinant of all processes and phenomena. Naturally, with her death, the world loses its foothold and all possibilities for further existence and development. Such a position absolutely correlates with the European Petrarchistsʼ concept of a woman, where the death of the main character was traditionally accompanied by hyperbolized cries, titanic suffering and signs of cosmic disturbance. Conclusion. Based on the direct textual parallels between “Canzoniere” and John Donneʼs poems we present the following research results. In “The Anniversaries” the English author involved almost the entire arsenal of images (the main character as a queen, the soul of the universe, its heart and beauty, foundation, measure and harmony, etc.), motifs (the rapid decline and complete destruction of the world due to the tragic death of the heroine; the ennobling influence that Elizabeth had on everything surrounding her; poetic creativity, which may be immortal, but is unable to reflect the external and internal perfection of the girl; the importance of neglecting the earthly for the sake of the heavenly, for what the short life of the heroine can serve as an example; a woman as the cause of a manʼs death; the unearthly, angelic nature of the main character, who had no place on the sinful earth, etc.), means and methods of images creation (portrayal of a female character using images of gold and various kinds of jewelry; excessive idealization of the heroine; excessive hyperbolization and affectation; complex rhetorical periods, etc.), which in Francesco Petrarchʼs “Canzoniere” dealt with the untimely death of Laura, its irreparable consequences and the protagonistʼs suffering on this occasion. At the same time, John Donne significantly expanded the semantic volume of the borrowed Petrarchan elements, and even those which were only barely outlined in the works of the Italian poet himself, acquired additional details (for example, the comparison of Elizabeth with the state) and scale (pictures of the soul’s afterlife journey through the heavenly spheres) in the English writerʼs texts. It has been shown that many of the Petrarchan images are even more hyperbolic in John Donneʼs poems (grave world, corpse world). At the same time, it has been established that certain images and motifs are also somewhat simplified, schematized (the heroine’s singing in the heavenly choir). Therefore, it has been concluded that, when turning to “Canzoniere” as a source of the toposes and concepts, the writer did not just use them as a convenient but frozen language strategy, which was typical for most European Petrarchists, but creatively reinterpreted them according to his own intentions. It has been proved that reading John Donneʼs “The First” and “The Second Anniversary” through the prism of Petrarchan receptions not only allows us to put these texts into a very organic analytical context, but also helps to solve certain applied problems, such as, for example, the problem of the prototype of the main character.

The multimodal freight network models are traditionally based on the four stages approach in which generation, distribution, modal split and assignment are seen as separated modules. An alternative approach is to represent the multimodal network by a service network, in which each transport operation (loading, unloading, transhipment...) is represented by a dedicated “virtual link”. In such a network, modal choice and assignment can be combined in a single step. This approach, adopted by several authors and known as “super-networks” or “virtual networks” gives interesting results, but requires dedica­ted assignment methods, which have to distribute flows from an origin to a particular destination over several alternative routes.It comes out that equilibrium assignment techniques are not appropriate when they are used for long haul trips and when only aggregate data on the demand is available. Indeed, the obtained results appear to be very close to an All-or-Nothing assignment, and don’t lead to a sufficient distribution over alternative routes. This can mainly be explained by the fact that, for inter-city, interregional or international traffic, only a small part of the trips is performed during the peak periods in congested areas. Moreover, the demand data collected for large areas is often only available on an annual basis, making it difficult to estimate what happens at a given period of the day. This paper describes a multi-flow, multimodal assignment procedure to be applied to large virtual networks for freight transport. At the end, an application of the suggested assignment method on the detailed trans-European network will be presented. Les modèles multimodaux de fret sont traditionnellement basés sur le modèle à quatre étapes dans lequel la génération, la distribution, la répartition modale et l’affectation sont autant de modules séparés. Une approche alternative est de représenter le réseau multimodal par un réseau de service dans lequel cha­que opération de transport (chargement, déchargement, transbordement…) est représentée par un « arc virtuel » dédié. Dans un tel réseau, le choix modal et l’affectation peuvent être effectués en une seule étape. Cette appro­che, adoptée par plusieurs auteurs et connue sous les vocables « super-ré­seaux » ou « réseaux virtuels », donne des résultats intéressants, mais nécessi­te la mise en œuvre de méthodes d’affectation appropriées, qui peuvent répar­tir les flux d’une origine à une destination particulière entre des itinéraires alternatifs.Il s’avère que les techniques d’affectation d'équilibre ne conviennent pas lorsqu’elles sont utilisées sur des réseaux internationaux pour lesquels seules des données agrégées pour la demande sont disponibles. En effet, les solu­tions obtenues sont très proches d’une affectation « tout ou rien », et n’abou­tissent donc pas à une répartition suffisante entre chemins alternatifs. Ceci peut principalement être expliqué par le fait que, dans le trafic interurbain, interrégional ou international, une petite partie du voyage seulement est faite pendant les heures de pointes dans des zones congestionnées. De plus, les données de demande collectées sur de grandes zones sont souvent disponibles uniquement sur base annuelle, rendant difficile une estimation fine pour une période donnée du jour. C’est dans ce contexte que cet article décrit une tech­nique d’affectation multi-flux qui peut être appliquée sur de grands réseaux virtuels de transport de fret. L’article se termine avec une application de la méthode au réseau transeuropéen.

Wireless Mesh Network (WMN) is a convincing theme to many net researchist because of its minimal effort in sending, straightforwardness in the establishment and heartiness in activity. Notwithstanding, current routing protocols intended for MANET, can't work productively in WMN on the grounds that spine in WMN shaped by Mesh Router has low portability and are not put under power and memory duress. In this paper, we are coming with a new idea of routing using geographic multipath, which will be beneficial for an Infrastructural WMNetwork and also don't depend on node's location. The proposed protocols has awareness, about the node's congestion and the node's location of all next neighbors, and utilize Hop-Count array technique. Furthermore, with help of a procedure of congestion-cognizant, nodes can select the perfect connection with adequate bandwidth for the requirement of comer traffic. In the proposed protocol for routing we accomplish various remarkable characteristics of Hop-count array (metric) depend on routing algorithm: straightforwardness, durability and feasibility of affectation. Results demonstrate that throughput increments extraordinarily with our proposed protocol when contrasted with unadulterated AODV and AOMDVin heavily loaded traffic situation.

From an interview with “Mr A”, executive producer and co-creator of the Getaway in Stockholm (GiS) films: Mr A: Yeah, when I tell my girlfriend, ‘You should watch this, it’s good, it’s a classic, it’s an old movie’ and she thinks it’s, like, the worst. And when I actually look at it and it is the worst, it is just a car chase … [Laughs] But you have to look a lot harder, to how it is filmed, you have to learn … Because, you can’t watch car racing for instance, because they are lousy at filming; you get no sensation of speed. If you watch the World Rally Championship it looks like they go two miles an hour. The hardest thing [of the whole thing] is capturing the speed … I want to engage with the notion of “speed” in terms of the necessary affects of automobility, but first I will give some brief background information on the Getaway in Stockholm series of films. Most of the information on the films is derived from the interview with Mr A carried out over dinner in Stockholm, October 2004. Contact was made via e-mail and I organised with the editors of Autosalon Magazine for an edited transcription to be published as an incentive to participate in the interview. Mr A’s “Tarantino-style” name is necessary because the films he makes with Mr X (co-creator) and a small unnamed group of others involve filming highly illegal acts: one or two cars racing through the streets of Stockholm evading police at sustained speeds well over 200 km/h. Due to a quirk in Swedish traffic law, unless they are caught within a certain time frame of committing driving offences or they actually admit to the driving offences, then they cannot be charged. The Swedish police are so keen to capture these renegade film makers that when they appeared on Efterlyst (pron: ef-de-list; the equivalent of “Sweden’s Most Wanted”) instead of the normal toll-free 1-800 number that viewers could phone to give tips, the number on the screen was the direct line to the chief of Stockholm’s traffic unit. The original GiS film (2000) was made as a dare. Mr A and some friends had just watched Claude Lelouch’s 1976 film C’était un Rendez-vous. Rumour has it that Lelouch had a ten-minute film cartridge and had seen how a gyro stabilised camera worked on a recent film. He decided to make use of it with his Ferrari. He mounted the camera to the bonnet and raced through the streets of Paris. In typical Parisian style at the end of the short nine minute film the driver parks and jumps from the Ferrari to embrace a waiting woman for their “rendezvous”. Shortly after watching the film someone said to Mr A, “you don’t do that sort of thing in Stockholm”. Mr A and Mr X set out to prove him wrong. Nearly all the equipment used in the filming of the first GiS film was either borrowed or stolen. The Porsche used in the film (like all the cars in the films) was lent to them. The film equipment consisted of, in Mr A’s words, a “big ass” television broadcast camera and a smaller “lipstick” camera stolen from the set of the world’s first “interactive” reality TV show called The Bar. (The Bar followed a group of people who all lived together in an apartment and also worked together in a bar. The bar was a “real” bar and served actual customers.) The first film was made for fun, but after Mr A and his associates received several requests for copies they decided to ramp up production to commercial levels. Mr A has a “real job” working in advertising; making the GiS films once a year is his main job with his advertising job being on a self-employed, casual basis. As a production team it is a good example of amateurs becoming semi-professionals within the culture industries. The GiS production team distributes one film per year under the guise of being a “documentary” which allows them to escape the wrath of Swedish authorities due to further legal quirks. Although they still sell DVDs from their Website, the main source of income comes from the sale of the worldwide distribution rights to British “powersports” specialist media company Duke Video. Duke also sells a digitally remastered DVD version of Rendezvous on their Website. As well as these legitimate distribution methods, copies of all six GiS films and Rendezvous are available on the internet through various peer-to-peer file-sharing networks. Mr A says there isn’t much he can do about online file sharing besides asking people to support the franchise if they like the films by buying the DVDs. There are a number of groups making films for car enthusiast using similar guerilla film production methods. However, most of the films are one-offs or do not involve cars driven at such radical speeds. An exception was another Swedish film maker who called himself “Ghostrider” and who produced similar films using a motorbike. Police apprehended a man who they alleged is “Ghostrider” in mid-2004 within the requisite timeframe of an offence that had been allegedly committed. The GiS films alongside these others exist within the automotive cultural industry. The automotive cultural industry is a term I am using to describe the overlap between the automotive industry and the cultural industries of popular culture. The films tap in to a niche market of car enthusiasts. There are many different types of car enthusiasts, everything from petite-bourgeois vintage-car restorers to moral panic-inducing street racers. Obviously the GiS films are targeted more towards the street racing end of the spectrum, which is not surprising because Sweden has a very developed underground street racing scene. A good example is the Stockholm-based “Birka Cup”: a quasi-professional multi-round underground street-racing tournament with 60,000 SEK (approx. AUD$11,000) prize money. The rules and rankings for the tournament are found on the tournament Website. To give some indication of what goes on at these events a short teaser video clip for the 2003 Birka Cup DVD is also available for download from the Website. The GiS films have an element of the exotic European-Other about them, not only because of the street-racing pedigree exemplified by the Birka Cup and similar underground social institutions (such as another event for “import” street racers called the “Stockholm Open”), but because they capture an excess within European car culture normally associated with exotic supercars or the extravagant speeds of cars driven on German autobahns or Italian autostradas. For example, the phrase “European Styling” is often used in Australia to sell European designed “inner-city” cars, such as the GM Holden Barina, a.k.a. the Vauxhall Corsa or the Opel Corsa. Cars from other regional manufacturing zones often do not receive such a specific regional identification; for example, cars built in Asian countries are described as “fully imported” rather than “Asian styling”. Tom O’Dell has noted that dominant conception of automobility in Sweden is different to that of the US. That is, “automobility” needs to be qualified with a national or local context and I assume that other national contexts in Europe would equally be just as different. However, in non-European, mainly post-colonial contexts, such as Australia, the term “European” is an affectation signaling something special. On a different axis, “excess” is directly expressed in the way the police are “captured” in the GiS films. Throughout the GiS series there is a strongly antagonist relation to the police. The initial pre-commercial version of the first GiS film had NWA’s “Fuck the Police” playing over the opening credits. Subsequent commercially-released versions of the film had to change the opening title music due to copyright infringement issues. The “bonus footage” material of subsequent DVDs in the series represents the police as impotent and foolish. Mr A describes it as a kind of “prank” played on police. His rationale is that they live out the fantasy that “everyone” wishes they could do to the police when they are pulled over for speeding and the like; as he puts it, “flipping the bird and driving off”. The police are rendered foolish and captured on film, which is an inversion of the normative traffic-cop-versus-traffic-infringer power relation. Mr A specifies the excess of European modernity to something specific to automobility, which is the near-universal condition of urbanity in most developed nations. The antagonism between the GiS drivers and the police is figured as a duel. The speed of the car(s) obviously exceeds what is socially and legally acceptable and therefore places the drivers in direct conflict with police. The speed captured on film is in part a product of this tension and gives speed a qualitative cultural dimension beyond a simple notion from rectilinear physics of speed as a rate of motion. The qualitative dimension of speed as been noted by Peter Wollen: Speed is not simply thrilling in itself, once sufficiently accelerated, but also enables us to enter exposed and unfamiliar situations, far removed from the zones of safety and normality – to travel into space, for instance, beyond the frontiers of the known. (106) Knowledge is subsumed by the dialect of road safety: “safety” versus “speed”. Knowledge takes on many forms and it is here that speed gains its complexity. In the high-school physics of rectilinear motion speed refers to a rate. Mr A discusses speed as a sensation (“thrill” in the language of Wollen) in the quote at the beginning of the essay. If the body develops sensations from affects and percepts (Deleuze and Guattari 179-83), then what are the affects and percepts that are developed by the body into the sensation of speed? The catchphrase for the GiS films is “Reality Beats Fiction By Far!” The “reality” at stake here is not only the actuality of cars traveling at high speeds within urban spaces, which in the vernacular of automotive popular culture is more “real” than Hollywood representations, but the “reality” of automobilised bodies engaging with and “getting away” from the police. Important here is that the police serve as the symbolic representatives of the governmental institutions and authorities that regulate and discipline populations to be automobilised road users. The police are principally symbolic because one’s road-user body is policed, to a large degree, by one’s self; that is, by the perceptual apparatus that enables us to judge traffic’s rates of movement and gestures of negotiation that are indoctrinated into habit. We do this unthinkingly as part of everyday life. What I want to suggest is that the GiS films tap into the part of our respective bodily perceptual and affective configurations that allow us to exist as road users. To explain this I need to go on a brief detour through “traffic” and its relation to “speed”. Speed serves a functional role within automobilised societies. Contrary to the dominant line from the road safety industry, the “speed limit” we encounter everyday on the road is not so much a limit, but a guide for the self-organisation of traffic. To think the “speed limit” as a limit allows authorities to imagine a particular movement-based threshold of perception and action that bestows upon drivers the ability to negotiate the various everyday hazard-events that constitute the road environment. This is a negative way to look at traffic and is typical of the (post)modernist preoccupation with incorporating contingency (“the accident”) into behavioural protocol and technical design (Lyotard 65-8). It is not surprising that the road safety industry is an exemplary institution of what Gilles Deleuze called the “control society”. The business of the road safety industry is the perpetual modulation of road user populations in a paradoxical attempt to both capture (forecast and study) the social mechanics of the accident-event while postponing its actualisation. Another way to look at traffic is to understand it as a self-organising system. Ilya Prigogine and Robert Herman modeled vehicle traffic as two flows – collective and individual – as a function of the concentration and speed of vehicles. At a certain tipping point the concentration of traffic is such that individual mobility is subsumed by the collective. Speed plays an important role both in the abstract sense of a legislated “speed limit” and as the emergent consistency of mobile road users distributed in traffic. That is, automotive traffic does not move at a constant speed, but nominally moves at a consistent speed. The rate and rhythms of traffic have a consistency that we all must become familiar with to successfully negotiate the everyday system of automobility. For example, someone simply walking becomes a “pedestrian” in the duration of automobilised time-space. Pedestrians must embody a similar sense of the rate of traffic as that perceived by drivers in the cars that constitute traffic. The pedestrian uses this sense of speed when negotiating traffic so as to cross the road, while the driver uses it to maintain a safe distance from the car in front and so on. The shared sense of speed demands an affective complicity of road-user bodies to allow them to seamlessly incorporate themselves into the larger body of traffic on a number of different registers. When road users do not comply with this shared sense of speed that underpins traffic they are met with horn blasts, rude figure gestures, abuse, violence and so on. The affects of traffic are accelerated in the body and developed by the body into the sensations and emotions of “road rage”. Road users must performatively incorporate the necessary dispositions for participating with other road users in traffic otherwise they disrupt the affective script (“habits”) for the production of traffic. When I screened the first GiS film in a seminar in Sweden the room was filled with the sound of horrified gasps. Afterwards someone suggested to me that they (the Swedes) were more shocked than I (an Australian) about the film. Why? Is it because I am a “hoon”? We had all watched the same images heard the same sounds, yet, the “speeds” were not equal. They had experienced the streets in the film as a part of traffic. Their bodies knew just how slow the car was meant to be going. The film captured and transmitted the affects of a different automobilised body. Audiences follow the driver “getting away” from those universally entrusted (at least on a symbolic level) with the governance of traffic – the police – while, for a short period, becoming a new body that gets away from the “practiced perception” (Massumi 189) of habits that normatively enable the production of traffic. What is captured in the film – the event of the getaway – has the potential to develop in the body of the spectator as the sensation of “speed” and trigger a getaway of the body. Acknowledgement I would like to acknowledge the generous funding from the Centre for Cultural Research and the College of Arts, Education and Social Sciences, University of Western Sydney, in awarding me the 2004 CCR CAESS Postgraduate International Scholarship, and the support from my colleagues at the Advanced Cultural Studies Institute of Sweden where I carried out this research as a doctoral exchange student. References Deleuze, Gilles. “Postscript on Control Societies”. Negotiations. Trans. Martin Joughin. New York: Columbia UP, 1995. Deleuze, Gilles, and Felix Guattari. What Is Philosophy? Trans. Graham Burchill and Hugh Tomlinson. London: Verso, 1994. Getaway in Stockholm series. 21 Oct. 2005 http://www.getawayinstockholm.com>. Lyotard, Jean François. The Inhuman: Reflections on Time. Trans. Geoffrey Bennington and Rachel Bowlby. Stanford, California: Stanford UP, 1991. Massumi, Brian. “Parables for the Virtual: Movement, Affect, Sensation”. Post-Contemporary Interventions. Eds. Stanley Fish and Fredric Jameson. Durham, London: Duke UP, 2002. O’Dell, Tom. “Raggare and the Panic of Mobility: Modernity and Everyday Life in Sweden.” Car Culture. Ed. Daniel Miller. Oxford: Berg, 2001. 105-32. Prigogine, Ilya, and Robert Herman. “A Two-Fluid Approach to Town Traffic.” Science 204 (1979): 148-51. Wollen, Peter. “Speed and the Cinema.” New Left Review 16 (2002): 105–14. Citation reference for this article MLA Style Fuller, Glen. "The Getaway." M/C Journal 8.6 (2005). echo date('d M. Y'); ?> <http://journal.media-culture.org.au/0512/07-fuller.php>. APA Style Fuller, G. (Dec. 2005) "The Getaway," M/C Journal, 8(6). Retrieved echo date('d M. Y'); ?> from <http://journal.media-culture.org.au/0512/07-fuller.php>.

Nous nous intéressons à la modélisation de l'affectation du trafic routier, c'est à dire, à la façon dont les flux de véhicules se répartissent à l'intérieur d'un réseau de routes, en particulier lorsqu'une information est diffusée aux usagers, par exemple grâce à un panneau à messages variables. Le réseau est décrit à l'aide de points de choix où les flux de véhicules peuvent se séparer pour emprunter différentes options, en fonction du coût prévu de chacune de ces options. Ce coût prévu est modélisé à l'aide d'un nombre flou qui permet de représenter l'imprécision et l'incertitude qui résident dans la prévision en situation dynamique. La diffusion d'une information routière modifie justement ce coût prévu, en rendant, par exemple, plus précise une estimation, ou plus certaine l'occurrence d'un événement. Nous proposons 2 types de modèles de répartition des flux entre les options basées sur les 2 approches classiques rencontrées dans les modèles d'affectation (modèles stochastiques et équilibre de Wardrop). Ils permettent de retrouver les résultats de ces modèles lorsque la situation n'est pas dynamique mais certaine et précise. Les solutions proposées sont encore loin d'être opérationnelles, mais nous fournissons un nouveau formalisme intéressant qui permet d'introduire dans la modélisation de l'affectation l'incertitude liée à l'aspect dynamique du problème et de modéliser l'influence de l'information routière
We are interested in traffic assignment modeling (that is describing the way trafic spreads over a road network) especially when traffic information is given to drivers, for example using variable message signs. Network is described with some choice-nodes where trafic streams can split between different options, regarding the predicted cost of each option. This predicted cost is modeled with a fuzzy number, representing both vagueness and uncertainty due to the dynamic aspect of the problem. . . [etc. ]

Le problème de l'affectation du trafic consiste à déterminer les itinéraires empruntés par les usagers d'une infrastructure de transport. Ce problème a fait l'objet de nombreuses études, en particulier dans le contexte de l'analyse des scénarios de développement des infrastructures routières et des stratégies tarifaires. Sa formulation repose principalement sur le principe de l'équilibre de Wardrop, où les itinéraires sont définis de manière que les utilisateurs n'aient aucun intérêt à modifier leurs trajets. En l'absence d'une politique tarifaire, cet équilibre garantit l'équité des temps de trajet entre chaque paire origine-destination. Cependant, il entraîne un coût social car l’équité ne garantit pas une utilisation optimale du réseau.L'évolution des systèmes de transport intelligents, ainsi que l'avènement des véhicules autonomes et connectés, présentent de nouveaux défis pour les approches actuelles de résolution du problème d'affectation du trafic. Ces approches reposent sur plusieurs itérations de simulation pour estimer les temps de trajet et ajuster les itinéraires en suivant la descente du gradient. Cependant, ces méthodes présentent deux limitations majeures. D'une part, elles ne permettent pas de générer en temps réel des itinéraires équilibrés. D'autre part, elles ne tiennent pas compte de la capacité des véhicules autonomes et connectés à acquérir des informations précises sur les conditions de circulation. Les travaux de cette thèse visent à aborder ces deux limites des approches actuelles. L'objectif est de définir les interactions entre les divers systèmes intelligents du trafic, afin de développer une approche capable de tirer parti des informations pertinentes pour générer en temps réel des itinéraires à la fois équitables et efficaces. Pour atteindre cet objectif, il est essentiel d'utiliser la modélisation et la simulation du trafic à base d’agents.Les premiers systèmes multi-agents proposés de cette thèse sont inspirés des différentes hypothèses d'affectation du trafic de la littérature. Toutefois, les résultats obtenus ont montré quelques lacunes. Il est apparu que la connaissance précise des temps de trajet dépend principalement de la gestion des conflits aux nœuds du réseau. En conséquence, cette thèse propose une nouvelle approche basée sur la réservation multi-agent des intersections. Cette approche permet d’affecter dynamiquement la demande des véhicules autonomes et connectés. Les résultats montrent qu'il est possible de garantir l'équité des trajets fournis en temps-réel tout en améliorant significativement l’efficacité du trafic
The problem of traffic assignment consists of determining the routes taken by users of a transportation infrastructure. This problem has been the subject of numerous studies, particularly in the context of analyzing scenarios for the development of road infrastructure and pricing strategies. Its formulation is primarily based on the principle of Wardrop equilibrium, where routes are defined in such a way that users have no incentive to change their paths. In the absence of pricing policies, this equilibrium ensures fairness in travel times between each origin-destination pair. However, it results in a social cost because fairness does not necessarily allow for optimal use of the network.The evolution of intelligent transportation systems, as well as the emergence of connected and autonomous vehicles, present new challenges to current approaches for solving the traffic assignment problem. These approaches rely on several simulation iterations to estimate travel times and adjust vehicle routes following gradient descent. However, these methods have two major limitations. Firstly, they do not enable real-time generation of balanced routes. Secondly, they do not take into account the ability of connected and autonomous vehicles to acquire precise information about traffic conditions. The work of this thesis aims to address these two limitations of current approaches. The goal is to define the interactions between various intelligent transportation systems, capable of leveraging relevant information to generate real-time routes that are both equitable and efficient. To achieve this objective, the thesis uses agent-based traffic modeling and simulation.The initial multi-agent systems proposed in this thesis draw inspiration from various traffic assignment assumptions in the literature. However, the results obtained revealed some shortcomings. Simulations show that the precise knowledge of travel times primarily depends on managing conflicts at network nodes. As a result, this thesis proposes a new approach based on multi-agent reservation of intersections. This approach dynamically assigns itineraries for autonomous and connected vehicles. The results show that it is possible to compute fair routes in real-time while significantly improving traffic efficiency

Mes travaux de recherche ont pour sujet unificateur : les déplacements et les réseaux de transport ; et ils ont été traités par une approche unique, la modélisation physico-économique à caractère mathématique et algorithmique.
Une telle modélisation comporte quatre aspects : un contenu sémantique, à caractère physique ou économique ; une formulation mathématique ; un solveur technique ; un aspect empirique (métrologie, statistique, économétrie).
Les disciplines mises en œuvre sont variées : théorie des réseaux, optimisation, informatique algorithmique, probabilités et statistiques, et aussi économie, socio-économie et physique du trafic. Mes contributions théoriques concernent la théorie des réseaux, l'économie du transport et la physique du trafic.
Mes travaux se répartissent en quatre thèmes :
A. La mesure et la modélisation du trafic. Au niveau local d'une route, j'ai analysé la relation entre flux et vitesse en mettant en cohérence l'analyse désagrégée, probabiliste au niveau du mobile individuel ; et l'analyse macroscopique en termes de flux et de distribution statistique des temps.
B. La modélisation des réseaux et des cheminements. L'équilibre entre offre de transport et demande de déplacement conjugue une dimension spatiale - topologique, une dimension temporelle, et une dimension comportementale - économique. Les enjeux de modélisation concernent : la représentation de l'offre et la demande ; la formulation et les propriétés d'existence – unicité – stabilité ; les algorithmes. Je me suis intéressé à la diversité des comportements ; et à la modélisation fine de l'offre et à la dimension temporelle.
C. L'analyse socio-économique des déplacements. Je me suis intéressé à l'usage de divers moyens de transport et à la prospection de leur clientèle potentielle ; au choix d'horaire de déplacement ; aux caractéristiques à la fois économiques et dynamiques de la congestion.
D. La distribution spatiale des déplacements et des activités. Je me suis intéressé d'une part à l'observation des flux par relation origine-destination (O-D) et à l'inférence statistique des matrices O-D ; et d'autre part, à la justification microéconomique des déplacements en raison de la localisation et de l'utilité des activités.

Cette thèse porte sur les modèles d'affectation dynamique du trafic et l'équilibre offre-demande du trafic, afin d'en évaluer la capacité opérationnelle et d'en développer certains aspects. L'analyse porte essentiellement sur le modèle LADTA de Leurent (2003), dont les hypothèses physiques et économiques sont proches de l'affectation statique tout en ajoutant la dimension chronologique et un traitement par file d'attente de la congestion sur les arcs du réseau de transport. Nous reprenons la formulation analytique de ce modèle dans une expression abstraite qui est générique pour l'affectation dynamique, ce qui nous permet d'élaborer des approches algorithmiques variées en termes de formulation mathématique et de variables endogènes basiques. Nous discutons des algorithmes d'équilibrage et proposons un algorithme hybride qui traite conjointement des volumes et des temps par arcs. Nous donnons une analyse formalisée du mesurage de convergence, et nous élaborons des critères de convergence rigoureux et parcimonieux. Le modèle dans une version simplifiée, les algorithmes d'équilibrage et les critères de convergence ont été programmés dans un prototype, et expérimentés sur des cas d'école, afin d'établir le comportement des algorithmes et des critères, et de procéder à des réglages pour certains paramètres.

Le trafic aérien en Europe représente environ 30 000 vols quotidiens actuellement. Selon les prévisions de l’organisme Eurocontrol, ce trafic devrait croître de 70% d’ici l’année 2020 pour atteindre 50 000 vols quotidiens. L’espace aérien, découpé en zones géographiques appelées secteurs de contrôle, atteindra bientôt son niveau de saturation vis-à-vis des méthodes actuelles de planification et de contrôle. Afin d’augmenter la quantité de trafic que peut absorber le système, il est nécessaire de diminuer la charge de travail des contrôleurs aériens en les aidant dans leur tâche de séparation des avions. En se fondant sur les demandes de plans de vol des compagnies aériennes, nous proposons une méthode de planification des trajectoires en 4D permettant de présenter au contrôleur un trafic dont la plupart des conflits auront été évités en avance. Cette planification s’établit en deux étapes successives, ayant chacune un unique degré de liberté : une allocation de niveaux de vol permettant la résolution des conflits en croisière puis une allocation d’heures de décollage permettant de résoudre les conflits restants. Nous présentons des modèles pour ces deux problèmes d’optimisation fortement combinatoires, que nous résolvons en utilisant la programmation par contraintes ou les algorithmes évolutionnaires, ainsi que des techniques permettant de prendre en compte des incertitudes sur les heures de décollage ou le suivi de trajectoire. Les simulations conduites sur l’espace aérien français mènent à des situations où tous les conflits sont évités, avec des retards alloués de l’ordre d’une minute en moyenne (80 à90 minutes pour le vol le plus retardé) et un écart par rapport à l’altitude optimale limité à un niveau de vol pour la quasi totalité des vols. La prise en compte d’incertitudes de manière statique dégrade fortement ces solutions peu robustes, mais nous proposons un modèle dynamique utilisant une fenêtre glissante susceptible de prendre en compte des incertitudes de quelques minutes avec un impact réduit sur le coût de l’allocation
Air traffic in Europe represents about 30,000 flights each day and forecasts from Eurocontrol predict a growth of 70% by 2020 (50,000 flights per day). The airspace, made up of numerous control sectors, will soon be saturated given the current planification and control methods. In order to make the system able to cope with the predicted traffic growth, the air traffic controllers workload has to be reduced by automated systems that help them handle the aircraft separation task. Based on the traffic demand by airlines, this study proposes a new planning method for 4D trajectories that provides conflict-free traffic to the controller. This planning method consists of two successive steps, each handling a unique flight parameter : a flight level allocation phase followed by a ground holding scheme. We present constraint programming models and an evolutionary algorithm to solve these large scale combinatorial optimization problems, as well as techniques for improving the robustness of the model by handling uncertainties of takeoff times and trajectory prediction. Simulations carried out over the French airspace successfully solved all conflicts, with a mean of one minute allocated delay (80 to 90 minutes for the most delayed flight) and a discrepancy from optimal altitude of one flight level for most of the flights. Handling uncertainties with a static method leads to a dramatic increase in the cost of the previous non-robust solutions. However, we propose a dynamic model to deal with this matter, based on a sliding time horizon, which is likely to be able to cope with a few minutes of uncertainty with reasonable impact on the cost of the solutions

Le travail développé dans cette thèse porte sur l'élaboration d'un système de tarification dynamique des secteurs aériens pour réduire la congestion de l'espace. Un modèle décrivant la relation entre les prix d'entrée dans les secteurs et le choix des routes et des périodes de décollage par les compagnies aériennes est proposé. Les paramètres du modèle sont estimés en minimisant la différence entre un nombre de vols observés et un nombre de vols issus du modèle. Les prix de secteurs sont calculés de manière à minimiser la différence entre un nombre de vols définis par une cible et un nombre de vols issus du modèle. La cible correspond à une répartition du trafic dans le temps et dans l'espace qui conduit à une forte réduction de la congestion. Deux stratégies de tarification sont envisagées. La première consiste à établir des prix par secteur et par période indépendamment les uns des autres. La deuxième stratégie de tarification consiste à limiter le nombre de valeurs de prix et à affecter un niveau de prix à chaque secteur à chaque période. Plusieurs algorithmes basés sur la méthode du gradient, le recuit simulé et la méthode Tabou sont développés pour résoudre les problèmes d'optimisation. Tous ces algorithmes sont testés et comparés sur trois scénarios de trafic. Les résultats de l'optimisation et des simulations de trafic montrent que la tarification mise en place permet d'orienter partiellement le choix des compagnies et de diminuer les pointes de congestion.

Les conditions de circulation sur un réseau routier subissent souvent de la congestion. Selon ses sources, la congestion routière peut être classée en deux catégories : la congestion récurrente déterminée par les lois de trafic et la congestion non-récurrente due aux incidents, accidents ou autres aléas sur la route. Grâce à l'avancement des technologies, notamment en informatique, communication et techniques de traitement des données, l'exploitant est devenu capable de détecter les perturbations, de mesurer les effets et même d'anticiper l'état du trafic afin de mieux adapter ses actions d'exploitation. L'information dynamique concernant les conditions de trafic permet aux usagers de réduire l'inconfort et d'effectuer leur choix d'itinéraire de manière plus raisonnable. Pour l'exploitant, le service d'information aux usagers peut servir à la gestion du trafic. Nous avons étudié la contribution potentielle de l'information dynamique au profit individuel des usagers et à la performance collective du système en prenant en compte : i) la congestion récurrente et non-récurrente ; ii) des différents comportements de choix d'itinéraire en fonction de l'accessibilité à l'information ; iii) d'autres actions de gestion du trafic menées par l'exploitant. Un modèle théorique avec une application analytique sur un réseau élémentaire de deux routes parallèles, une paire origine-destination et deux classes d'usagers respectivement informée ou non-informée nous a permis de retirer de nombreuses indications : i) la diffusion excessive de l'information avec un contenu " neutre " dégrade à la fois le profit individuel et la performance du système ; ii) l'information dynamique avec certain contenu " coopératif " peut contribuer l'optimisation du système sans causer le problème d'acceptabilité ; iii) l'information dynamique et d'autres mesures de gestion dynamique s'interagissent de manière complémentaire à l'optimisation du trafic

Un modèle représente un système, ses composants et les interactions entre composants. Il sert à analyser et simuler les interactions, en déduisant les conséquences logiques d'hypothèses sur les variables d'état du système, ou sur des variables de contrôle ou de perturbation. Comment juger, ou mieux mesurer, si le modèle est proche de la réalité ? La thèse établit les principes d'un tel examen, appelé audit technique d'un modèle. Il s'agit de détecter, identifier, et si possible réduire, les erreurs et les incertitudes, que nous décomposons en quatre classes : (i) erreur de conception (quels mécanismes explicatifs constituent la composition conceptuelle, quelles schématisations ?), (ii) erreur formelle (la synthèse mathématique des mécanismes explicatifs dans une formule caractéristique, doit être conforme au contenu conceptuel et cohérente), (iii) erreur algorithmique (le dispositif de résolution fournit-il vraiment une solution ? Avec quelle précision ?), (iv) enfin une incertitude de type économétrique qui englobe l'erreur d'estimation et l'erreur exogène a priori sur les inputs. Chaque classe d'erreur relève d'une discipline spécifique, ce qui confère autant de dimensions à l'audit : audit conceptuel à base d'analyse systémique, audit formel à caractère mathématique, audit algorithmique de caractère physique ou informatique, audit économétrique. Nous proposons une méthode systématique d'audit. Nous l'appliquons à un modèle d'équilibre entre offre et demande, précisément un modèle de choix d'itinéraire sur un réseau avec une offre sujette à congestion et une demande qui arbitre de façon diversifiée entre prix et temps. Nous établissons une formule caractéristique (inéquation variationnelle en dimension finie) dont la solution jouit de propriétés d'existence et d'unicité ; nous proposons et testons plusieurs algorithmes et critères de convergence ; nous effectuons l'analyse de sensibilité pour propager l'erreur économétrique exogène à travers le modèle.

La méthode de Frank Wolfe offre une approche efficace pour la résolution des programmes convexes avec contraintes linéaires. Dans le contexte des réseaux de transport l'algorithme se réduit à une série de problèmes de plus court chemin et de recherches unidimensionnelles. Nous présentons une approche unifiée de la résolution d'une large variété de problèmes lies au système de planification du trafic urbain par la méthode de Frank Wolfe. Enfin, nous proposons une modification de l'algorithme de Frank Wolfe pour la résolution du problème de l'affectation du trafic urbain.

This chapter follows the trail of books from Charles Lamb's library. Those old books have a perennial fascination—even if, in themselves, they were not worth much. By focusing on the dispersal of Charles Lamb's library in New York in 1848 and the story of book collectors in America, the chapter brings together and recalls to life the leading figures from the transatlantic book world at midcentury, a time when Americans were busy assembling libraries, public as well as private, from masses of old books in circulation. The chapter reviews how Lamb inspired American bibliophiles, as well as the language necessary to combat the idea that bookishness was an Old World affectation incompatible with life in the New. The chapter concludes by arguing that the library sale catalogue of virtually every major American book collector in the nineteenth century who owned books from Charles Lamb's library appealed to its audience by boasting of its association with Saint Charles. It emphasizes that to some degree, Lamb's popularity was owing to the fact that he was a working man of letters: he served as a mouthpiece for all those whose weekdays were spent in the grind of economic survival but whose evenings and fugitive hours were all spent with books.