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An investigation was made into the characteristics of program elements and removals of Weapon Replaceable Assemblies aggregated at the system level for the purpose of developing a method to predict removals during initial provisioning periods. From examination of nine avionic systems over a 28 month period a binomial model was developed using a removal rate based on aircraft-months as a program element. The model is to be used before Fleet data are generated by obtaining aircraft-month estimates from the contractor and removal rate estimates from similar operational equipments. A probability distribution reflecting the degree of certainty is selected as a prior estimate. Then, as Fleet experience is accumulated the distribution is updated using Bayesian techniques and maturity growth curves. This distribution is used to give an estimate of current removal rate and to extrapolate to future removal rates.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Multiple antennas promise high data capacity for wireless communications. Most space-time coding schemes in literature focus on the rich scatter environment. In this paper, we argue that minimax criterion is a good design criterion for space-time codes over the avionic telemetry channels. This design criterion is different than those of space-time codes over rich scattering Rayleigh fading channels. Theoretical and numerical results show that the codes with optimal performance in Rayleigh fading channels do not necessarily have optimal performance in avionic telemetry channels. Therefore, the space-time codes should be carefully designed/selected when used in the avionic telemetry channels.

De nos jours, les systèmes embarqués sont les éléments Cœurs des Systèmes avioniques. De plus en plus de fonctions sont intégrées et de ce fait leurs complexités croît. Afin que cette complexité puisse rester maîtrisable, l’architecture des systèmes avionique a également évolué de façon à minimiser les interactions entre les équipements. Cette évolution des Architectures a introduit, au niveau avionique, la notion de réseau largement répandue dans le monde dit « consumer ». Nos travaux de Recherche ont pour but d’accompagner cette évolution architecturale en minimisant l’impact des ruptures technologiques qu’il a été nécessaire d’introduire afin de supporter cette évolution. Pour cela, nous proposons une approche qui va nous permettre de dé-risquer chaque nouvelle brique technologique avant son introduction au sein des Systèmes Embarqués. Cette introduction pourra donc être réalisée en ayant au préalable défini les conditions ainsi que les limites d’utilisation de chaque nouvelle technologie, qu’elle soit matérielle et/ou logicielle. / Nowadays, Embedded Systems are key elements of the Avionic Systems. As more and more functions are integrated, their complexity goes increasing. In order to keep mastering this complexity, Avionic Systems Architecture has also evolved so as to minimize the interactions between equipment. This evolution of the Architectures introduced, at the avionic level, the notion of network widely spread in the consumer domain. Our research works aim at accompanying this architectural evolution by minimizing the impact of the technological breakthroughs which were necessary to introduce to support this evolution. For that purpose, we propose an approach which is going to allow us to derisk every new technological brick before its introduction within the Embedded Systems. This introduction can thus be performed by having beforehand defined the conditions as well as the limits of use of every new technology that it is Hardware and/or Software.

ARINC 664/AFDX (Avionics Full Duplex Switched Ethernet) protocol is a leading onboard communication technology in civil aviation. As AFDX is a new technology, unit cost of the hardware devices are high and protocol is open to changes. This thesis discusses the design of an AFDX End System application for test environment with a software based solution with cheap COTS (Commercial offthe shelf) equipment, explains the implementation of the software and analysis the performance.

L’évolution actuelle des systèmes embarqués à bord des systèmes complexes (avions,satellites, navires, automobiles, etc.) les rend de plus en plus vulnérables à des attaques,en raison de : (1) la complexité croissante des applications ; (2) l’ouverture des systèmes vers des réseaux et systèmes qui ne sont pas totalement contrôlés ; (3) l’utilisation de composants sur étagère qui ne sont pas développés selon les méthodes exigées pour les systèmes embarqués critiques ; (4) le partage de ressources informatiques entre applications, qui va de pair avec l’accroissement de puissance des processeurs. Pour faire face aux risques de malveillances ciblant les systèmes embarqués, il est nécessaire d’appliquer ou d’adapter les méthodes et techniques de sécurité qui ont fait leurs preuves dans d’autres contextes : Méthodes formelles de spécification, développement et vérification ;Mécanismes et outils de sécurité (pare-feux, VPNs, etc.) ; Analyse de vulnérabilités et contre-mesures. C’est sur ce dernier point que portent nos travaux de thèse.En effet, cet aspect de la sécurité a peu fait l’objet de recherche, contrairement aux méthodes formelles. Cependant, il n’existe pas actuellement de modèle formel capable de couvrir à la fois des niveaux d’abstraction suffisamment élevés pour permettre d’exprimer les propriétés de sécurité désirées, et les détails d’implémentation où se situent la plupart des vulnérabilités susceptibles d’être exploitées par des attaquants : fonctions des noyaux d’OS dédiées à la protection des espaces d’adressage, à la gestion des interruptions et au changement de contextes, etc. ; implémentation matérielle des mécanismes de protection et d’autres fonctions ancillaires. C’est sur ces vulnérabilités de bas niveau que se focalise notre étude.Nos contributions sont résumées par la suite. Nous avons proposé une classification des attaques possibles sur un système temps-réel. En nous basant sur cette classification,nous avons effectué une analyse de vulnérabilité sur un système réaliste : une plateforme avionique expérimentale fournie par Airbus. Il s’agit d’un noyau temps-réel critique ordonnancé avec plusieurs autres applications, le tout exécuté sur une plateforme Freescale QorIQ P4080. C’est à travers une application dite « malveillante », présente parmi l’en-semble des applications, que nous essayons de modifier le comportement des autres applications ou du système global pour détecter des vulnérabilités. Cette méthode d’analyse de vulnérabilités a permis de détecter plusieurs problèmes concernant les accès mémoire,la communication entre applications, la gestion du temps et la gestion des erreurs qui pouvaient conduire à la défaillance du système global. Enfin, nous avons proposé des contre-mesures spécifiques à certaines attaques et des contre-mesures génériques pour le noyau temps-réel qui permet d’empêcher une application d’obtenir des accès privilégiés ou encore de perturber le comportement du système. / Security is becoming a major concern for embedded computing systems in variouscritical industrial sectors (aerospace, satellites, automotive, etc.). Indeed, recent trendsin the development and operation of such systems, have made them more and morevulnerable to potential attacks, for the following reasons : 1) increasing complexity of theapplications ; 2) openness to applications and networks that are note completely undercontrol ; 3) Use Commercial-Off-The-Shelf (COTS) hardware and software components ;4) Resource sharing among different applications, driven by the increase of processorscapabilities.To improve the security of such systems, it is necessary to apply or adapt methodsand techniques that have proven their efficiency in other contexts : Formal methods forspecification, development and verification ; Security mechanisms and tools (firewalls,VPNs, etc.) ; Vulnerability assessment and countermeasure provision.The research carried out in this thesis adresses the latter technique. This aspect ofsecurity analysis cannot be easily covered by current formal methods, since no exist-ing model is able to cover both high-level abstractions, where security properties canbe defined, and low-level implementation details, where most vulnerabilities that couldbe exploited by attackers lie : OS kernel implementation of address space protection,interrupt management, context switching, etc. ; hardware implementation of protectionmechanisms and other ancillary functions. Very few research projects are addressing thisaspect of security, which is the main objective of this thesis. In particular, our researchfocuses on low-level vulnerabilities, but contrarily with common practice, we aim todiscover and analyze them during the development process.Our contributions are summarized as follows. We elaborated a classification of low-level vulnerabilities for different implementations of real-time embedded systems. Basedon this classification, we carried out a vulnerability analysis study on a realistic system :An experimental avionic platform provided by Airbus. It consists of a critical real-timekernel scheduling the execution of different applications on a freescale QorIQ P4080platform. The identification and analysis of vulnerabilities is carried out based on a“malicious” application hosted on the platform that attempts to corrupt the behavior ofthe other applications or the global system considering different types of low level attacks.Such experiments allowed us to identify some problems related to the management ofmemory accesses, the communication between applications, time management and errorhandling that could lead to the global system failure.We have also proposed genericcounter measures to protect the real-time kernel against specific attacks, and to preventa given application from escalating its privileges or trying to compromise the systembehavior

Dans le domaine des réseaux, deux précieux objectifs doivent être atteints, à savoir la QoS et la sécurité, plus particulièrement lorsqu’il s’agit des réseaux à caractère critique et à fortes contraintes temporelles. Malheureusement, un conflit existe : tandis que la QoS œuvre à réduire les temps de traitement, les mécanismes de sécurité quant à eux requièrent d’importants temps de traitement et causent, par conséquent, des délais et dégradent la QoS. Par ailleurs, les systèmes temps réel, la QoS et la sécurité ont très souvent été étudiés séparément, par des communautés différentes. Dans le contexte des réseaux avioniques de données, de nombreux domaines et applications, de criticités différentes, échangent mutuellement des informations, souvent à travers des passerelles. Il apparaît clairement que ces informations présentent différents niveaux de sensibilité en termes de sécurité et de QoS. Tenant compte de cela, le but de cette thèse est d’accroître la robustesse des futures générations de réseaux avioniques de données en contrant les menaces de sécurité et évitant les ruptures de trafic de données. A cet effet, nous avons réalisé un état de l’art des mécanismes de sécurité, de la QoS et des applications à contraintes temporelles. Nous avons, ensuite étudié la nouvelle génération des réseaux avioniques de données. Chose qui nous a permis de déterminer correctement les différentes menaces de sécurité. Sur la base de cette étude, nous avons identifié à la fois les exigences de sécurité et de QoS de cette nouvelle génération de réseaux avioniques. Afin de les satisfaire, nous avons proposé une architecture de passerelle de sécurité tenant compte de la QoS pour protéger ces réseaux avioniques et assurer une haute disponibilité en faveur des données critiques. Pour assurer l’intégration des différentes composantes de la passerelle, nous avons développé une table de session intégrée permettant de stocker toutes les informations nécessaires relatives aux sessions et d’accélérer les traitements appliqués aux paquets (filtrage à états, les traductions d’adresses NAT, la classification QoS et le routage). Cela a donc nécessité, en premier lieu, l'étude de la structure existante de la table de session puis, en second lieu, la proposition d'une toute nouvelle structure répondant à nos objectifs. Aussi, avons-nous présenté un algorithme permettant l’accès et l’exploitation de la nouvelle table de session intégrée. En ce qui concerne le composant VPN IPSec, nous avons détecté que le trafic chiffré par le protocole ESP d’IPSec ne peut pas être classé correctement par les routeurs de bordure. Afin de surmonter ce problème, nous avons développé un protocole, Q-ESP, permettant la classification des trafics chiffrés et offrant les services de sécurité fournis par les protocoles AH et ESP combinés. Plusieurs techniques de gestion de bande passante ont été développées en vue d’optimiser la gestion du trafic réseau. Pour évaluer les performances offertes par ces techniques et identifier laquelle serait la plus appropriée dans notre cas, nous avons effectué une comparaison basée sur le critère du délai, par le biais de tests expérimentaux. En dernière étape, nous avons évalué et comparé les performances de la passerelle de sécurité que nous proposons par rapport à trois produits commerciaux offrant les fonctions de passerelle de sécurité logicielle en vue de déterminer les points forts et faibles de notre implémentation pour la développer ultérieurement. Le manuscrit s’organise en deux parties : la première est rédigée en français et représente un résumé détaillé de la deuxième partie qui est, quant à elle, rédigée en anglais. / QoS and security are two precious objectives for network systems to attain, especially for critical networks with temporal constraints. Unfortunately, they often conflict; while QoS tries to minimize the processing delay, strong security protection requires more processing time and causes traffic delay and QoS degradation. Moreover, real-time systems, QoS and security have often been studied separately and by different communities. In the context of the avionic data network various domains and heterogeneous applications with different levels of criticality cooperate for the mutual exchange of information, often through gateways. It is clear that this information has different levels of sensitivity in terms of security and QoS constraints. Given this context, the major goal of this thesis is then to increase the robustness of the next generation e-enabled avionic data network with respect to security threats and ruptures in traffic characteristics. From this perspective, we surveyed the literature to establish state of the art network security, QoS and applications with time constraints. Then, we studied the next generation e-enabled avionic data network. This allowed us to draw a map of the field, and to understand security threats. Based on this study we identified both security and QoS requirements of the next generation e-enabled avionic data network. In order to satisfy these requirements we proposed the architecture of QoS capable integrated security gateway to protect the next generation e-enabled avionic data network and ensure the availability of critical traffic. To provide for a true integration between the different gateway components we built an integrated session table to store all the needed session information and to speed up the packet processing (firewall stateful inspection, NAT mapping, QoS classification and routing). This necessitates the study of the existing session table structure and the proposition of a new structure to fulfill our objective. Also, we present the necessary processing algorithms to access the new integrated session table. In IPSec VPN component we identified the problem that IPSec ESP encrypted traffic cannot be classified appropriately by QoS edge routers. To overcome this problem, we developed a Q-ESP protocol which allows the classifications of encrypted traffic and combines the security services provided by IPSec ESP and AH. To manage the network traffic wisely, a variety of bandwidth management techniques have been developed. To assess their performance and identify which bandwidth management technique is the most suitable given our context we performed a delay-based comparison using experimental tests. In the final stage, we benchmarked our implemented security gateway against three commercially available software gateways. The goal of this benchmark test is to evaluate performance and identify problems for future research work. This dissertation is divided into two parts: in French and in English respectively. Both parts follow the same structure where the first is an extended summary of the second.

The modern military aircraft can be defined as a System of Systems (SoS); several distinct systems operating simultaneously across boundary interfaces. As the on-board subsystems have become more complex and diverse, the development process has become more isolated. When considering thermal management of distributed heat loads, the aircraft has become a collection of individually optimised components and subsystems, rather than the implementation of a single system to perform a given task. Avionic thermal management is quickly becoming a limiting factor of aircraft performance, reliability and effectiveness. The challenge of avionic thermal management is growing with the increasing complexity and power density of avionic packages. The aircraft relies on a heat rejection growth capacity to accommodate the additional through-life avionic heat loads. Growth capacity is defined as an allowable thermal loading growth designed into the system by the underutilisation of spatial and cooling supply at aircraft introduction; however, this is a limited resource and aircraft subsystem cooling capability is reaching a critical point. The depleted growth capacity coupled with increased avionic power demands has led to component thermal failure. However, due to the poor resolution of existing data acquisition, experimental facilities or thermodynamic modeling, the exact inflight-operating conditions remain relatively unknown. The knowledge gap identified in this work is the lack of definitive methodology to generate high fidelity data of in-flight thermal conditions of fast-jet subsystems and provide evidence towards effective future thermal management technologies. It is shown that, through the development of a new methodology, the knowledge gap can be reduced and as an output of this approach the unknown system behaviour can be defined. A multidisciplinary approach to the replication, analysis and optimisation of a fast-jet TMS is detailed. The development of a new Ground Test Facility (GTF) allows previously unidentified system thermal behaviour to be evaluated at component, subsystem and system level. The development of new data to characterise current thermal performance of a fast jet TMS allows recommendations of several new technologies to be implemented through a component led integrative system optimisation. This approach is to consider the TMS as a single system to achieve a single goal of component thermal management. Three technologies are implemented to optimise avionic conditions through the minimisation of bleed air consumption, improve avionic reliability through increased avionic component isothermalisation and increase growth capacity through improved avionic heat exchanger fin utilisation. These component level technologies improved system level performance. A reduction in TMS bleed air consumption from 1225kg to 510kg was found to complete a typical flight profile. A peak predicted aircraft specific fuel consumption saving of 1.23% is seen at a cruise flight condition because of this approach to avionic thermal management.

Development of software for electronic systems in the aviation industry is strongly regulated by pre-defined standards. The aviation industry spends significant costs of development in ensuring flight safety and showing conformance to these standards. Some safety requirements can be satisfied by performing formal verification. Formal verification is seen as a way to reduce costs of showing conformance of software with the requirements or formal specifications. Therefore, the correctness of formal specifications is critical. Writing formal specifications is at least as difficult as developing software [36]. This work proposes an approach to generate formal specifications from example data. This example data illustrates the natural language requirements and represents the ground truth about the system. This work eases the task of an engineer who has to write formal specifications by allowing the engineer to specify the example data instead. The use of a relationship model and a marking syntax and semantics are proposed that make the creation of formal specifications goal oriented. The evaluation of the approach shows that the proposed syntax and semantics capture more information than is strictly needed to generate formal specifications. The relationship model reduces the computational load and only produces formal specifications that are interesting for the engineer.

Yes / In this paper, a novel multilink selection framework is developed for different applications with various quality of service (QoS) requirements in avionic systems, based on the multi-attribute decisionmaking model. Two metaheuristic algorithms are proposed to solve this model while optimizing the multilink selection performances. Multilink configuration and multi-homing capabilities are generally required for aircrafts operating in a heterogeneous wireless network environment. The first algorithm, called Analytic Hierarchy Process and Simulated Annealing (AHP-SA), utilises a two-phase process. In Phase one, an analytic hierarchy process (AHP) is used to choose the decision weight factors. Then, in Phase two, a simulated annealing process is applied to select suitable networks, for various service requests, based on the weights obtained from first phase. Further, to improve customer satisfaction, Simulated Annealing algorithm for Simultaneous Weights and Network Selection Optimisation (SA-SWNO) is developed, in which a simulated annealing algorithm is applied to dynamically optimise weight factors of objective functions and the request-to-network assignment matrix. Simulation results demonstrates that both proposed algorithms outperform the commonly used price-based or QoS-based network selection scheme with much higher averaged satisfaction degree and lower computational complexity. / Cockpit NetwOrk CoMmunications Environment Testing (COMET) Project under the European Commission’s Program Clean Sky2 in partnership with the European Aeronautical Industry