The Economics of Truck Toll Lanes

This paper extends an earlier paper by the authors ("Maintenance and congestion pricing with competing roads" presented at ERSA 2005) by introducing two user groups: heavy and light vehicles (viz. trucks and cars). This extension is important since heavy vehicles generate higher congestion and (much) higher pavement damage externalities than do light vehicles. The model features a simple road network with two routes linking a common origin and destination. Pavement quality on each route depreciates with usage and due to natural weathering. Three administration regimes are analysed. The first two regimes are the second best and first best optima. In the second-best regime maintenance levels are chosen for the two routes, but no tolls are applied. In the first-best regime, both maintenance levels and tolls are set to support an optmal division of traffic between the two routes as well as an optimal quality of service. The final regime is a Duopoly. In this regime each route is owned and operated by a different firm that maximises its own profit by choosing a maintenance level and a toll. The analysis (which is still in progress) entails solution and comparison of the outcomes of the three administration regimes. Among other things, we are interested to see in which regimes routes are differentiated so that one route is mainly used by heavy vehicles and the other by light vehicles. Preliminary results suggest that (as in the case of homogeneous users) private ownership is distorted towards excessive tolls and low maintenance effort.

A Monocentric City With Discrete Transit Stations

We extend the monocentric model by considering a discrete number of accessible mass transit stations. Households combine two modes for their daily home-to-work trip: a first mode for terminal access to stations and a second (long haul) mode which consists in radial mass transit axes. The urban equilibrium, i.e. city size and households' distribution, is derived as a function of the mass transit network and the distribution of land housing capacity. Then at the urban equilibrium the land rent is peaked at transit stations and decreases with the travel cost from the city center rather than with the distance to it. Accordingly, the housing lot size increases with the travel cost from the city center. These features distinguish our framework from previous monocentric models. Our analysis is based on the assumptions that land-owners are absent and city is open (the households' level of utility is given and the population size is endogenous). For numerical illustration, the model is calibrated to a selected rail network in the Paris area. A sensitivity analysis of the urban structure and land-use equilibrium is conducted with respect to the key model parameters.

Conception et implémentation de nouvelles configurations de matrice de Butler en technologies planaire et conforme

Dans ce rapport, nous présentons des nouvelles configurations de matrice de Butler en technologies planaire et conforme. L'étude comporte deux volets portant respectivement sur la conception d'une matrice de Butler à large bande ayant 3 GHz de bande passante (opérant de 4.5 jusqu'à 7.5 GHz), et la conception d'une matrice de Butler conforme à 2.4 GHz. Dans un premier temps, nous présentons une étude théorique et expérimentale de deux coupleurs qui sont les composants clés de la matrice de Butler large bande. Le premier coupleur est directionnel, large bande, à couplage par fente et conçu en technologie CB-CPW, permettant d'éviter l'utilisation de croissements dans la matrice de Butler grâce à sa caractéristique multicouches. Le deuxième coupleur, étant directionnel et large bande, conçu en topologie elliptique et en technologie CBCPW, permettant ainsi de minimiser les pertes et d'assurer une bande passante plus large comparé aux coupleurs hybrides conventionnels. La matrice de Butler, ainsi conçue à base de ces deux coupleurs, offre des bonnes performances couvrant la bande de 4.5 jusqu'à 7,5 GHz. Dans l'étape suivante, nous détaillons nos travaux de recherches liés à une architecture de matrice de Butler conforme opérant à 2.4 GHz en technologie microruban. La topologie conforme à été déjà explorée avec les réseaux d'antennes de différentes formes (cylindriques, sphériques...). L'originalité de nos travaux de recherche, consiste à mettre au point tout un système d'antenne intelligente (matrice de Butler + réseau d'antennes) en topologie conforme permettant de lever le défi concernant la géométrie, ce qui facilite l'intégration du système à n'importe quel milieu de travail et évite les coûts d' installations supplémentaires. En plus avoir le système d'antenne intelligente en entier conforme (réseau d'antenne + matrice de Butler), permet d'avoir une couverture de 360° dépendamment de sa configuration. Les résultats obtenus ont montré des bonnes performances en termes de directivité et de contrôle de diagramme de rayonnement. Une étude paramétrique concernant l'effet de la courbure de la structure sur les diagramme de rayonnement a été détaillée dans la suite

Multistatic radar optimization for radar sensor network applications

The design of radar sensor networks (RSN) has undergone great advancements in recent years. In fact, this kind of system is characterized by a high degree of design flexibility due to the multiplicity of radar nodes and data fusion approaches. This thesis focuses on the development and analysis of RSN architectures to optimize target detection and positioning performances. A special focus is placed upon distributed (statistical) multiple-input multipleoutput (MIMO) RSN systems, where spatial diversity could be leveraged to enhance radar target detection capabilities. In the first part of this thesis, the spatial diversity is leveraged in conjunction with cognitive waveform selection and design techniques to quickly adapt to target scene variations in real time. In the second part, we investigate the impact of RSN geometry, particularly the placement of multistatic radar receivers, on target positioning accuracy. We develop a framework based on cognitive waveform selection in conjunction with adaptive receiver placement strategy to cope with time-varying target scattering characteristics and clutter distribution parameters in the dynamic radar scene. The proposed approach yields better target detection performance and positioning accuracy as compared with conventional methods based on static transmission or stationary multistatic radar topology. The third part of this thesis examines joint radar and communication systems coexistence and operation via two possible architectures. In the first one, several communication nodes in a network operate separately in frequency. Each node leverages the multi-look diversity of the distributed system by activating radar processing on multiple received bistatic streams at each node level in addition to the pre-existing monostatic processing. This architecture is based on the fact that the communication signal, such as the Orthogonal Frequency Division Multiplexing (OFDM) waveform, could be well-suited for radar tasks if the proper waveform parameters are chosen so as to simultaneously perform communication and radar tasks. The advantage of using a joint waveform for both applications is a permanent availability of radar and communication functions via a better use of the occupied spectrum inside the same joint hardware platform. We then examine the second main architecture, which is more complex and deals with separate radar and communication entities with a partial or total spectrum sharing constraint. We investigate the optimum placement of radar receivers for better target positioning accuracy while reducing the radar measurement errors by minimizing the interference caused by simultaneous operation of the communication system. Better performance in terms of communication interference handling and suppression at the radar level, were obtained with the proposed placement approach of radar receivers compared to the geometric dilution of precision (GDOP)-only minimization metric

Cordon pricing in the Monocentric city model: Theory and application to Ile-de- France

International audienceWe propose a method to compute an equilibrium solution for the monocentric city model with traffic congestion, and to quantify the im- pact of cordon tolls on social surplus. The focus of this paper is on the comparison of road pricing of one and two cordons, with the no toll and first-best situations as benchmarks. We find that a one-cordon toll yields a social efficiency of 63% with respect to first-best, and that an optimal two-cordon toll increases the efficiency to 73%. Both policies have a pos- itive impact on CO2 emissions because they reduce the average length of trips and reduce the road size

Congestion pricing and long term urban form: Application to Ile-de-France

We propose an efficient algorithm that solves the monocentric city model with traffic congestion, and use it to explore the impact of congestion pricing on urban forms and, hence, on transport volume, CO2 emissions and energy consumption. The application focuses on the region Ie-de-France. Four pricing policies are considered: no toll, where transport cost is equal to the vehicle operating cost, cordon toll where users pay the toll when they drive inside cordon region linear toll (optimal under the class of linear tolls) and optimal toll (or first-best toll). The linear toll is equivalent to an increase in the vehicle operating cost. It performs well with respect to the first-best solution but, since it applies identically to all trips, it is not likely to be relevant in practice. By comparison to the no-toll situation, optimal congestion pricing reduces the radius of the city and the average travel distance by 34% and 15%, respectively.Nous proposons un algorithme de résolution du modèle monocentrique de transport avec congestion. Nous utilisons cet algorithme afin d'explorer l'impact de différents schémas de tarification de la congestion sur la forme urbaine, et par conséquent, sur les véhiculeskilomètres (émissions de CO2) à long terme. L'application empirique concerne la région Îlede- France. Quatre régimes de tarification sont considérés : (i) absence de tarification, où une taxe linéaire reflète le coût d'usage du véhicule ; (ii) péage cordon, où les voitures payent pour passer à l'intérieur d'une zone donnée ; (iii) taxe linéaire optimale, proportionnelle à la distance parcourue (optimale dans la classe des taxes linéaires) ; et (iv) taxe optimale (optimum de premier rang). Par rapport à (i), la taxe optimale aboutit à des réductions de 34% et 15%, respectivement pour le rayon de la ville et la distance parcourue moyenne

Congestion pricing and long term urban form: Application to Ile-de-France

We propose an efficient algorithm that solves the monocentric city model with traffic congestion, and use it to explore the impact of congestion pricing on urban forms and, hence, on transport volume, CO2 emissions and energy consumption. The application focuses on the region Ie-de-France. Four pricing policies are considered: no toll, where transport cost is equal to the vehicle operating cost, cordon toll where users pay the toll when they drive inside cordon region linear toll (optimal under the class of linear tolls) and optimal toll (or first-best toll). The linear toll is equivalent to an increase in the vehicle operating cost. It performs well with respect to the first-best solution but, since it applies identically to all trips, it is not likely to be relevant in practice. By comparison to the no-toll situation, optimal congestion pricing reduces the radius of the city and the average travel distance by 34% and 15%, respectively.Monocentric model; Equilibrium computation; Transport pricing; Long term impacts

First-Best Congestion Pricing

International audienc

EVOLUTION AND THE COMPLEXITY OF FINITE AUTOMATA

Prisoner's dilemma played by finite automata is reviewed again using a slightly modified measure of complexity. At a first step, an equilibrium with a large number of possible outcomes is shown to hold. At a second stage, we consider a game of repeated interaction, and show that on (limit) equilibrium only cooperative actions are played. We conclude that cooperation is the result of a (complex) long interaction.Finite automata, complexity of the strategy, cooperation, evolution