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Caracterização e conformação de fluxos de tráfego ATM no ambiente de usuário / Characterization and shaping of ATM traffic flows in the user environmentRochol, Juergen January 2001 (has links)
Apresenta-se um framework que permite a caracterização, conformação e escalonamento de todas as categorias de serviços A TM, dentro do ambiente de usuário (CEP). Propõem-se um modelo de tráfego otimizado para este ambiente que oferece condições de garantias de QoS individuais para fluxos VBR, tempo real ou não, CBR, ABR e UBR. O modelo proposto, denominado de PCSTS (priority class services traffic shaping), inclui um módulo que permite a obtenção do descritor de tráfego de fluxos desconhecidos. Os fluxos são conformados de forma individual, e em tempo real, segundo um conformador baseado num algoritmo de escalonamento virtual duplo baseado no GCRA do ITU/ ATM Forum. Para a multiplexação dinâmica dos diferentes fluxos do ambiente de usuário, no enlace de acesso, é proposto um algoritmo de escalonamento EDD, modificado através de um sinal de realimentação entre conformador e escalonador, e desta forma tem-se condições de oferecer garantias de limite de atraso e jitter para fluxos individuais de serviços rt-VBR ou nrt-VBR. São apresentadas simulações, tanto da caracterização dos fluxos desconhecidos como da arquitetura do escalonador, que comprovam o comportamento esperado do modelo de tráfego PCSTS. / We present a framework that enhances the characterization, shaping and scheduling of ATM traffic flows for ali ATM service categories in the customer prernise equipment (CPE) environment. We propose an optirnized traffic model, capable to guarantee QoS parameters at per connection levei for VBR services, real time or not, CBR, ABR and UBR services. The model proposed, narned PCSTS (priority classes services traffic shaping), includes a module that performs the characterization of services with unknown traffic descriptor. The flows are shaped individually, in real time, through a shaper based on the double discrete time scheduling algorithm of the GCRA from ITU/ ATM Forum. For the dynarnic multiplexing of the different service flows , at the link levei, a modified EDD scheduling algorithm is proposed with a feedback signal between the scheduling and shaping modules. As a result, it is demonstrated that it is possible to grant jitter and delay bounds for the rt-VBR and nrt-VBR services. We present simulations of the traffic characterization module and of the scheduling architecture, for different services, which confirms the expected behavior of the PCSTS model.
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Link Dependent Origin-Destination Matrix Estimation : Nonsmooth Convex Optimisation with Bluetooth-Inferred Trajectories / Estimation de Matrices Origine-Destination-Lien : optimisation convexe et non lisse avec inférence de trajectoires BluetoothMichau, Gabriel 21 July 2016 (has links)
L’estimation des matrices origine-destination (OD) est un sujet de recherche important depuis les années 1950. En effet, ces tableaux à deux entrées recensent la demande de transport d'une zone géographique donnée et sont de ce fait un élément clé de l'ingénierie du trafic. Historiquement, les seules données disponibles pour leur estimation par les statistiques étaient les comptages de véhicules par les boucles magnétiques. Ce travail s'inscrit alors dans le contexte de l'installation à Brisbane de plus de 600 détecteurs Bluetooth qui ont la capacité de détecter et d'identifier les appareils électroniques équipés de cette technologie.Dans un premier temps, il explore la possibilité offerte par ces détecteurs pour les applications en ingénierie du transport en caractérisant ces données et leurs bruits. Ce projet aboutit, à l'issue de cette étude, à une méthode de reconstruction des trajectoires des véhicules équipés du Bluetooth à partir de ces seules données. Dans un second temps, en partant de l'hypothèse que l'accès à des échantillons importants de trajectoires va se démocratiser, cette thèse propose d'étendre la notion de matrice OD à celle de matrice OD par lien afin de combiner la description de la demande avec celle de l'utilisation du réseau. Reposant sur les derniers outils méthodologies développés en optimisation convexe, nous proposons une méthode d'estimation de ces matrices à partir des trajectoires inférées par Bluetooth et des comptages routiers.A partir de peu d'hypothèses, il est possible d'inférer ces nouvelles matrices pour l'ensemble des utilisateurs d'un réseau routier (indépendamment de leur équipement en nouvelles technologies). Ce travail se distingue ainsi des méthodes traditionnelles d'estimation qui reposaient sur des étapes successives et indépendantes d'inférence et de modélisation. / Origin Destination matrix estimation is a critical problem of the Transportation field since the fifties. OD matrix is a two-entry table taking census of the zone-to-zone traffic of a geographic area. This traffic description tools is therefore paramount for traffic engineering applications. Traditionally, the OD matrix estimation has solely been based on traffic counts collected by networks of magnetic loops. This thesis takes place in a context with over 600 Bluetooth detectors installed in the City of Brisbane. These detectors permit in-car Bluetooth device detection and thus vehicle identification.This manuscript explores first, the potentialities of Bluetooth detectors for Transport Engineering applications by characterising the data, their noises and biases. This leads to propose a new methodology for Bluetooth equipped vehicle trajectory reconstruction. In a second step, based on the idea that probe trajectories will become more and more available by means of new technologies, this thesis proposes to extend the concept of OD matrix to the one of link dependent origin destination matrix that describes simultaneously both the traffic demand and the usage of the network. The problem of LOD matrix estimation is formulated as a minimisation problem based on probe trajectories and traffic counts and is then solved thanks to the latest advances in nonsmooth convex optimisation.This thesis demonstrates that, with few hypothesis, it is possible to retrieve the LOD matrix for the whole set of users in a road network. It is thus different from traditional OD matrix estimation approaches that relied on successive steps of modelling and of statistical inferences.
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