Durch ein zunehmendes Verkehrsaufkommen wächst die Notwendigkeit den Verkehr in irgendeiner Form "intelligent" zu organisieren. In diesem Kontext sind die sogenannten Intelligent Transportation Systems (ITS) in den Fokus der Forschung gerückt. Diese Systeme zielen in der Regel auf die dynamische Optimierung der Routenwahlen von Verkehrsteilnehmern ab und sollen dadurch die Effizienz des Verkehrs verbessern. Grundsätzlich kann die Vorstellung einer optimalen Routenwahl in eine von zwei Kategorien eingeteilt werden: das Nash Gleichgewicht und die systemoptimale Routenwahl. Während Nash Gleichgewichte vergleichsweise einfach erzielt werden können-beispielsweise dadurch, dass jeder Fahrer seine Route egoistisch optimiert-ist das Erreichen des Systemoptimums ungleich schwerer. Dieses setzt nämlich voraus, dass alle Fahrer miteinander kooperieren und gemeinsam eine Lösung finden, von der die Gesamtheit als solche profitiert. In dieser Dissertation diskutieren wir das Design eines dezentralisierten ITS, welches in der Lage ist, eine systemoptimale Routenzuweisung im Straßennetzwerk zu approximieren, so dass die Fahrzeuge den price of anarchy nicht mehr in voller Höhe bezahlen müssen. Der besondere Fokus liegt hierbei auf der Anwendbarkeit des Ansatzes in realistischen Umgebungen, in denen eine Vielzahl von Schwierigkeiten zu erwarten ist. Dies beinhaltet beispielsweise eine unvollständige oder inkorrekte Sicht auf die aktuelle Verkehrssituation, das Fehlen von Wissen über Fahrzeuge, die erst in der Zukunft das Straßennetz betreten sowie ein nicht perfekter oder ressourcenlimitierter Kommunikationskanal. / The increasing amount of road traffic necessitates approaches that somehow "intelligently" organize traffic. In this context, the study of intelligent transportation systems (ITS) has been performed for some time. The goals of such systems include, e.g., is the dynamic optimization of route choices in a road network and hence the improvement of traffic conditions. There are two main methodologies how an optimization can be performed: the optimization towards a Nash equilibrium or towards a system optimum. While Nash equilibria can be easily reached, e.g., when every driver selfishly optimizes his own route, reaching the system optimum is a challenging task and requires all drivers to cooperate in an altruistic manner in favor of the system from a global perspective. In this work, we discuss the design of a decentralized ITS that is capable of approximating system optimal route choices in the network avoiding that the drivers have to pay the full price of anarchy. The focus, in this context, lies on the applicability to real life situations where a number of difficulties has to be expected, e.g., an incomplete or incorrect view on the current traffic situation, the lack of future knowledge and an imperfect or limited communication channel. Facing these challenging questions, we develop solutions to a number of research questions, that arise from the aforementioned difficulties. Before we can do so, we focus on the fundamental concepts of traffic optimization with an emphasis both on the theoretical concepts as well as their applicability in real world environments.

Les véhicules modernes sont équipés de périphériques permettant d'automatiser des tâches (changement de vitesse de transmission, régulation de vitesse, etc.) ou de fournir des services à l'utilisateur (aide à la conduite, détection d'obstacles, etc.). Les communications entre les véhicules permettent d'élargir ces services grâce à la collaboration de plusieurs véhicules (prévention des accidents, gestion du trafic routier, etc.). La multiplication de ces périphériques, de leurs interfaces et protocoles rend l'échange de données plus complexe. Par ailleurs, la communication inter- véhicules est plus contraignante à cause de la haute mobilité des véhicules. Dans cette thèse, nous proposons la conception d'un canal de communication Connect to All (C2A) qui permet d'assurer l'interopérabilité entre les périphériques embarqués dans un véhicule. En effet, il détecte la connexion à chaud d'un équipement, le reconnaît et lui permet d'échanger des données avec les autres périphériques connectés. La conception du canal commence par la modélisation de ce canal en utilisant deux techniques différentes (l'outil de modélisation et de vérification UPPAAL et le Langage de Description et de Spécification (LDS)). La vérification des modèles proposés a pour but de valider le fonctionnement. Ensuite, nous détaillons une implémentation réelle du canal sur une carte embarquée qui vise à démontrer la faisabilité du concept d'interopérabilité de C2A.Nous avons aussi étudié les effets de la mobilité dans la communication inter-véhiculaires grâce à une approche hybride mixant le routage et un service de localisation. Cette approche offre un mécanisme qui permet de réduire les coûts de la localisation des véhicules tout en augmentant les performances de routage. En plus, nous comparons deux applications de cette approche : Hybrid Routing and Grid Location Service (HRGLS) et Hybrid Routing and Hierarchical Location Service (HRHLS) avec des approches originelles pour démontrer la valeur ajoutée. Cette approche est enrichie avec un algorithme de prédiction de mobilité. Ce dernier permet de mieux cerner le déplacement des véhicules en les estimant. De même, l'approche hybride avec prédiction de mobilité Predictive Hybrid Routing and Hierarchical Location Service (PHRHLS) est comparée à HRHLS et l'approche originelle afin de révéler les bénéfices de la prédiction de mobilité. / Modern vehicles are equipped with various devices that aim to automate tasks (shift transmission, cruise control, etc.) or to provide services to the user (driver assistance, obstacle detection, etc.). Communications between vehicles help to expand these services through the collaboration of several vehicles (accident prevention, traffic management, etc.). The proliferation of these devices, their interfaces and protocols makes the data exchange more complex. In addition, inter-vehicle communication is more restrictive because of the vehicles' high mobility.In this work, we propose the design of a communication channel Connect to All (C2A) that ensures the interoperability between embedded devices in a vehicle. In fact, it detects the equipment connection, recognizes it and allows it to exchange data with other devices. The channel design starts by the modelling step using two different techniques (the model checker tool UPPAAL and the Specification and Description Language (SDL). Then, we validate the designed models. We also detail a concrete implementation of the channel on an embedded chip that aims to show the C2A interoperability concept feasibility.We also studied the mobility effects in the inter-vehicular communication through a hybrid approach mixing routing and location-based service. This approach provides a mechanism to reduce vehicle-tracking costs while increasing routing performances. Moreover, we compare two applications of this approach: Hybrid Routing and Grid Location Service (HRGLS) and Hybrid Routing and Hierarchical Location Service (HRHLS) with classical approaches to prove the added value. Then, this approach is improved with a mobility prediction algorithm. The latter allows a better understanding of the vehicle movements by estimating them. Similarly, the hybrid approach with mobility prediction Predictive Hybrid Routing and Hierarchical Location Service (PHRHLS) is compared with the basic approach and HRHLS in order to show the mobility prediction advantages.

Dans cette thèse nous nous sommes intéressés à sécuriser les réseaux véhiculaires ad hoc (VANETs) contre les attaques de déni de service (DoS) jugées comme étant les plus dangereuses pour ces réseaux. Notre travail peut être subdivisé en trois grandes parties.Dans un premier temps, nous avons étudié les différentes vulnérabilités auxquelles sont exposés les VANETs, spécialement les attaques DoS. Vu notre expertise en matière de la cryptographie, nous avons exploré, dégagé et classifié des solutions possibles à une grande panoplie de brèches de sécurité VANETs. En effet, nous avons montré que la cryptographie permet de résoudre divers problèmes de sécurité VANETs. Notre première contribution dans ce sens est un algorithme de génération de clés de groupe pour les convois de véhicules. Dans notre deuxième contribution nous avons conçu deux nouvelles méthodes de détection d’attaques DoS. Dans ce contexte, notre premier algorithme de détection est basé sur la régression linéaire, la logique floue ainsi que la définition de trois nouvelles métriques spécifiques VANETs. Dans notre deuxième algorithme de détection nous avons défini une nouvelle métrique à base de l'entropie de Shannon que nous avons introduite pour la première fois pour détecter tel type d’attaques. Notre troisième contribution a été consacrée à la réaction contre les attaques une fois détectées. Pour cela, nous avons eu recourt à l'utilisation des techniques offertes par la théorie des jeux. Nous avons proposé deux jeux non-coopératifs de réaction sous forme stratégique et extensive. Pour chacune des phases de détection et de réaction, les expérimentations ont été faites essentiellement pour les attaques greedy et jamming. Nos algorithmes proposés présentent l'avantage de la rapidité, d'être exécutés par n'importe quel nœud du réseau et ne nécessitent aucune modification du protocole IEEE 802.11p utilisée comme standard de la couche MAC et PHY des réseaux véhiculaires.Au cours de ce travail, nous avons pu participer à la sécurisation des réseaux VANETs. Cependant nous jugeons qu'il reste beaucoup à faire. A savoir par exemple, l'étude des solutions cryptographiques que nous avons menée nous a permis de découvrir à quel point l'usage de la cryptographie pour la sécurité des VANETs est un sujet assez vaste et qui nécessite d'être encore mieux exploré. Ceci constituera pour nous une ouverture assez prometteuse. / In this thesis we interested in securing Vehicular Ad hoc Networks (VANETs) against Denial of Service attacks (DoS) judged to be the most dangerous attacks to such networks. Our work can be divided into three main parts. First, we studied all the various possible existing vulnerabilities to which are exposed VANETs, we focused especially on denial of service attacks. Based on our expertise in cryptography, we explored, identified and classified the possible solutions to a wide range of VANET security breaches from a cryptographic point of view. Indeed, we showed that cryptography with its primitives and fairly powerful tools solves many VANET security problems. Our first contribution in this direction is a secure group key generation algorithm for VANET platoons. In our second contribution, we have developed two new techniques to detect denial of service attacks in VANET networks mainly characterized by the high mobility and frequent disconnections which considerably complicate the detection. Our first detection algorithm is based on the linear regression mathematical concept, fuzzy logic and three newly defined VANET appropriate metrics. In our second algorithm we define a new Shannon Entropy based metric that we introduced for the first time to detect DoS attacks in VANET. Our third contribution was devoted to the reaction against the detected attacks. For that, we used the techniques offered by game theory. We have proposed two non-cooperative reaction games in strategic and extensive forms. For both detection and reaction proposed schemes, experiments were made essentially for the greedy behavior and jamming attacks. All our proposed algorithms present the advantage of rapidity, to be executed by any node of the network and do not require any modification of the 802.11p MAC layer protocol used as a standard for VANETs. In this work, we have participated in securing VANETs, however we believe that much remains to be done. Namely, for example the study of cryptographic solutions we have conducted, allowed us to discover how the use of cryptography for VANET security is a fairly broad topic which needs to be better explored. This will be for us a very promising subject.

The objective of this research is to enhance the network performance under realistic mobile ad-hoc networks environments without modification of the standard. Overview of this research is summarized as follows: First, a packet-fragmentation technique to improve network throughput under the worst channel conditions is proposed. While the conventional packet-fragmentation technique research focuses only on random-bit errors, the proposed technique employs both random bit errors and hidden-node collisions. The analytical models based on Markov-chain model shows that the optimal fragmentation technique can effectively reduce the number of retransmissions caused by both collisions from hidden nodes and corrupted packets by random bit errors, and eventually improving throughput in noisy VANETs channels. As a second contribution, a dynamic service-channel allocation (DSCA) scheme is proposed to maximize the network throughput by dynamically assigning different service channels to the users. The theoretical analysis in this thesis will consider wireless access in the vehicular environment (WAVE) protocol, which is the main characteristic of the vehicular ad-hoc networks standard (the IEEE 802.11p). To summarize, the main contribution of this research is that two schemes will improve the network throughput significantly without modification of the standard. Therefore, there is no implementation issue to deploy the proposed schemes in real devices.

Vehicular Ad hoc Network (VANET) is a promising emerging technology that enables road safety, traffic management, and passengers and drivers comfort applications. Many applications require multi-hop routing; position-based routing (PBR) is a well-recognized routing paradigm that performs well in the vehicular context to enable these applications. However, there are many security challenges and various routing attacks which may prevent the deployment of PBR protocols. In this study, we propose a novel security scheme called ESPR to secure PBR protocols in VANETs. ESPR considers both digital signature and keyed Hash Message Authentication Code (HMAC) to meet the unique requirements of PBR. In ESPR, all legitimate members share a secret key. ESPR scheme applies a novel probabilistic key distribution to allow unrevoked members to update the shared secret key. Furthermore, it defines a set of plausibility checks that enables network members to detect and avoid PBR attacks autonomously. By conducting security analysis and performance evaluation, ESPR scheme demonstrated to outperform its counterparts in terms of communication overhead and delay while achieving robust and secure operation.

Vehicular Ad hoc Network (VANET) is a promising emerging technology that enables road safety, traffic management, and passengers and drivers comfort applications. Many applications require multi-hop routing; position-based routing (PBR) is a well-recognized routing paradigm that performs well in the vehicular context to enable these applications. However, there are many security challenges and various routing attacks which may prevent the deployment of PBR protocols. In this study, we propose a novel security scheme called ESPR to secure PBR protocols in VANETs. ESPR considers both digital signature and keyed Hash Message Authentication Code (HMAC) to meet the unique requirements of PBR. In ESPR, all legitimate members share a secret key. ESPR scheme applies a novel probabilistic key distribution to allow unrevoked members to update the shared secret key. Furthermore, it defines a set of plausibility checks that enables network members to detect and avoid PBR attacks autonomously. By conducting security analysis and performance evaluation, ESPR scheme demonstrated to outperform its counterparts in terms of communication overhead and delay while achieving robust and secure operation.

Vehicular Ad hoc Networks (VANETs) are emerging as a promising approach to improving traffic safety and providing a wide range of wireless applications for drivers and passengers. To perform reliable and trusted vehicular communications, one prerequisite is to ensure a peer vehicle’s credibility by means of digital certificates validation from messages that are sent out by other vehicles. However, in vehicular communication systems, certificates validation is more time consuming than in traditional networks, due to the fact that each vehicle receives a large number of messages in a short period of time. Another issue that needs to be addressed is the unsuccessful delivery of information between vehicles and other entities on the road as a result of their high mobility rate. For these reasons, we need new solutions to accelerate the process of certificates validation. In this thesis, we propose a certificate revocation status validation scheme using the concept of clustering; based on data mining practices, which can meet the aforementioned requirements. We employ the technique of k -means clustering to boost the efficiency of certificates validation, thereby enhancing the security of a vehicular ad hoc network. Additionally, a comprehensive analysis of the security of the proposed scheme is presented. The analytical results demonstrate that this scheme can effectively improve the validation of certificates and thus secure the vehicular communication in vehicular networks.

No description available.

There are still many challenges in the field of VANETs that encouraged researchers to conduct further investigation in this field to meet these challenges. The issue pertaining to routing protocols such as delivering the warning messages to the vehicles facing Non-Line of Sight (NLOS) situations without causing the storm problem and channel contention, is regarded as a serious dilemma which is required to be tackled in VANET, especially in congested environments. This requires the designing of an efficient mechanism of routing protocol that can broadcast the warning messages from the emergency vehicles to the vehicles under NLOS, reducing the overhead and increasing the packet delivery ratio with a reduced time delay and channel utilisation. The main aim of this work is to develop the novel routing protocol for a high-density environment in VANET through utilisation of its high mobility features, aid of the sensors such as Global Positioning System (GPS) and Navigation System (NS). In this work, the cooperative approach has been used to develop the routing protocol called the Co-operative Volunteer Protocol (CVP), which uses volunteer vehicles to disseminate the warning message from the source to the target vehicle under NLOS issue; this also increases the packet delivery ratio, detection of NLOS and resolution of NLOS by delivering the warning message successfully to the vehicle under NLOS, thereby causing a direct impact on the reduction of collisions between vehicles in normal mode and emergency mode on the road near intersections or on highways. The cooperative approach adopted for warning message dissemination reduced the rebroadcast rate of messages, thereby decreasing significantly the storm issue and the channel contention. A novel architecture has been developed by utilising the concept of a Context-Aware System (CAS), which clarifies the OBU components and their interaction with each other in order to collect data and take the decisions based on the sensed circumstances. The proposed architecture has been divided into three main phases: sensing, processing and acting. The results obtained from the validation of the proposed CVP protocol using the simulator EstiNet under specific conditions and parameters showed that performance of the proposed protocol is better than that of the GRANT protocol with regard to several metrics such as packet delivery ratio, neighbourhood awareness, channel utilisation, overhead and latency. It is also successfully shown that the proposed CVP could detect the NLOS situation and solves it effectively and efficiently for both the intersection scenario in urban areas and the highway scenario.

A real-time Vehicle Make and Model Recognition (VMMR) system is a significant component of security applications in Intelligent Transportation Systems (ITS). A highly accurate and real-time VMMR system significantly reduces the overhead cost of resources otherwise required. In this thesis, we present a VMMR system that provides very high classification rates and is robust to challenges like low illumination, occlusions, partial and non-frontal views. These challenges are encountered in realistic environments and high security areas like parking lots and public spaces (e.g., malls, stadiums, and airports). The VMMR problem is a multi-class classification problem with a peculiar set of issues and challenges like multiplicity, inter- and intra-make ambiguity among various vehicles makes and models, which need to be solved in an efficient and reliable manner to achieve a highly robust VMMR system. To reliably overcome the ambiguity challenges, a global features representation approach based on the Bag-of-Features paradigm is proposed. We extract key features from different make-model classes in an optimized dictionary, through two different dictionary building strategies. We represent different samples from each class with respect to the learned dictionary. We also present two classification schemes based on multi-class Support Vector Machines (SVMs): (1) Single multi-class SVM and (2) Attribute Bagging-based Ensemble of multi-class SVMs. These classification schemes allow simultaneous learning of the differences between global representations of different classes and the similarities between different shapes or generations within a same make-model class, to further overcome the multiplicity challenges for real-time application. Extensive experiments conducted using our approaches yield superior results for images that were occluded, under low illumination, partial camera views, or even non-frontal views, available in a recently published real-world VMMR dataset. The approaches presented herewith provide a highly accurate VMMR system for real-time applications in realistic environments.