Managing complexity is an increasing challenge in the development of embedded systems (ES). Some of the factors contributing to the increase in complexity are the growing complexity of hardware and software, and the increased pressure to deliver full-featured products with reduced time-to-market. An attractive approach to manage the software complexity, reduce time-to-market and decrease development costs lies in the adoption of component-based development that has been proven as a successful approach in other domains. Another raising challenge, due to complexity increase, in ES, is predictability, i.e., the ability to anticipate the behavior of a system at run-time. The particular predictability requirements of ES call for a development framework equipped with techniques and tools that can be applied to deal with requirements, such as timing, and resource utilization, already at early-stage of development. Modeling and formal analysis play increasingly important roles in achieving predictability, since they can help us to understand how systems function, validate the design and verify some important properties. In this thesis, we present a resource-aware framework for designing predictable component-based ES. The proposed framework consists of (i) the formally specified ProCom component model that takes into account the characteristics of control-intensive ES, and (ii) the resource-aware timed behavioral language - REMES for modeling and reasoning about components’ and systems’ functional and extra-functional behavior that includes relevant resource types for ES, associated analysis techniques for various resource-wise properties, and a set of associated tools. To demonstrate the potential application of our framework, we present a number of case studies, out of which one is an industrial research prototype, where ProCom and REMES are applied. / PROGRESS

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As predicted by Gordon Moore, the number of transistors on a chip has roughly doubled every two years. Microprocessors featuring over a billion transistors are no longer science fiction. For example, Intel’s Itanium 9000 series and Intel’s Xeon 7400 series of processors feature 1.7 and 1.9 billion transistors respectively. To keep up with the emerging needs of contemporary very large scale integration (VLSI) design, industrial hardware description languages (HDLs) like Verilog and VHDL must be significantly enhanced. This thesis pinpoints some of the main shortcomings of the latest Verilog standard (IEEE 1364-2005) and shows how to overcome them by extending the language in a backward compatible way. To be able to cope with more complex circuits, well-understood higher-level abstraction mechanisms are needed. Verilog is already equipped with promising generative constructs making it possible to concisely describe a family of circuits as a parameterized module; however these constructs suffer from two problems: First, their expressivity is limited and second, they are not adequately supported by current tools. For instance, there are no static guarantees about the properties of the description generated as a result of instantiating a generic description with particular parameter values. Addressing both problems while remaining backward compatible led us to select a statically typed two-level languages (STTL) formal framework. By formalizing a core subset of Verilog as an STTL, we were able to define a static type system capable of: 1) checking the realizability of a description, 2) detecting bus width mismatches and array bounds violations, and 3) providing parametric guarantees on the resources required to realize a generic description. The power of the chosen framework is once more demonstrated as it also allows us to enrich the language with a new set of constructs that are designed to be expanded away when instantiated. To experiment with these ideas we implemented VPP, a Verilog Preprocessor with a built-in type checker. VPP is an unobtrusive tool accepting extended Verilog descriptions but generating descriptions compatible with any tool compliant with the Verilog standard. Our experience throughout this research showed that STTLs present a particularly suitable framework to formalize and implement generative features of a language. / Rice University, National Science Foundation (NSF) SoD award 0439017, Intel Corporation, Semiconductor Research Corporation (SRC) Task ID 1403.001

In computing the available computing power has continuously fallen short of the demanded computing performance. As a consequence, performance improvement has been the main focus of processor design. However, due to the phenomenon called 'Power Wall' it has become infeasible to build faster processors by just increasing the processor's clock speed. One of the resulting trends in hardware design is to integrate several simple and power-efficient cores on the same chip. This design shift poses challenges of its own. In the past, with increasing clock frequency the programs became automatically faster as well without modifications. This is no longer true with many-core architectures. To achieve maximum performance the programs have to run concurrently on more than one core, which forces the general computing paradigm to become increasingly parallel to leverage maximum processing power. In this thesis, we will focus on the Reactive Stream Program (RSP). In stream processing, the system consists of computing nodes, which are connected via communication streams. These streams simplify the concurrency management on modern many-core architectures due to their implicit synchronisation. RSP is a stream processing system that implements the reactive system. The RSPs work in tandem with their environment and the load imposed by the environment may vary over time. This provides a unique opportunity to increase performance per watt. In this thesis the research contribution focuses on the design of the execution layer to run RSPs on tiled many-core architectures, using the Intel's Single-chip Cloud Computer (SCC) processor as a concrete experimentation platform. Further, we have developed a Dynamic Voltage and Frequency Scaling (DVFS) technique for RSP deployed on many-core architectures. In contrast to many other approaches, our DVFS technique does not require the capability of controlling the power settings of individual computing elements, thus making it applicable for modern many-core architectures, with which power can be changed only for power islands. The experimental results confirm that the proposed DVFS technique can effectively improve the energy efficiency, i.e. increase the performance per watt, for RSPs.

Chaque année en Europe, 1.300.000 accidents de la route ont comme conséquence 1.700.000 blessés. Le coût financier d’accidents de la route est évalué à 160 milliards d’euros (approximativement le même coût aux Etats-Unis). VANET (Vehicular Ad-hoc NETwork) est une des technologies clés qui peut permettre de réduire d’une façon significative le nombre d’accidents de la route (e.g. message d’urgence signalant la présence d’un obstacle ou d’un véhicule en cas de brouillard). En plus de l’amélioration de la sécurité et du confort des conducteurs et des passagers, VANET peut contribuer à beaucoup d’applications potentielles telles que la prévision et la détection d’embouteillages, la gestion d’infrastructure de système de transport urbain (e.g. système de transport intelligent multimodal) etc. Dans cette thèse, je présenterai un système embarqué dédié à la communication inter-véhicule particulièrement pour les applications sécuritaires de passagers et de conducteurs. Nos efforts de recherche et de développement sont centrés sur deux principaux objectifs : minimiser le temps de latence intra-noeud et le délai de communication inter-véhicule en prenant en compte le changement dynamique du VANET. De ce fait pour atteindre ces objectifs, des nouvelles approches (e.g. inter-couche ‘Cross-layering’) ont été explorées pour respecter les contraintes de ressource (QoS, mémoire, CPU et énergie de la communication inter-véhicule) d’un système embarqué à faible coût. Le système de communication embarqué proposé comporte deux composants logiciels principaux : un protocole de communication dénommé CIVIC (Communication Inter Véhicule Intelligente et Coopérative) et un système d’exploitation temps réel appelé HEROS (Hybrid Event-driven and Real-time multitasking Operating System). CIVIC est un protocole de communication géographique à faible consommation énergétique et à faible temps de latence (délai de communication). HEROS gère contextuellement l’ensemble du système (matériel et logiciel) en minimisant le temps de latence et la consommation des ressources (CPU et mémoire). En outre, le protocole de communication CIVIC est équipé d’un système de localisation LCD-GPS (Low Cost Differential GPS). Pour tester et valider les différentes techniques et théories, la plateforme matérielle LiveNode (LImos Versatile Embedded wireless sensor NODE) a été utilisée. En effet, la plateforme LiveNode permet de développer et de prototyper rapidement des applications dans différents domaines. Le protocole de communication CIVIC est basé sur la technique de ‘broadcast’ à un saut ; de ce fait il est indépendant de la spécificité du réseau. Pour les expérimentations, seule la norme d’IEEE 802.15.4 (ZigBee) a été choisie comme médium d’accès sans fil. Il est à noter que le médium d’accès sans fil ZigBee a été adopté comme le médium standard pour les réseaux de capteurs sans fil (RCSFs) et le standard 6LoWPAN ; car il est peu coûteux et peu gourmand en énergie. Bien que le protocole de communication à l’origine soit conçu pour répondre aux exigences de VANET, ses domaines d’application ne sont pas limités à VANET. Par exemple il a été utilisé dans différents projets tels que MOBI+ (système de transport urbain intelligent) et NeT-ADDED (projet européen FP6 : agriculture de précision). Les VANETs et les RCSFs sont les réseaux fortement dynamiques, mais les causes de changement topologique de réseau sont différentes : dans le réseau VANET, il est dû à la mobilité des véhicules, et dans le RCSF, il est dû aux pannes des noeuds sans fil. Il est à noter que le VANET et le RCSF sont généralement considérés comme un sous-ensemble du réseau MANET (réseau ad-hoc mobile). Cependant, ils sont réellement tout à fait différents du MANET classique, et leurs similitudes et différences seront expliquées en détail dans la thèse. La contribution principale de mes travaux est le protocole CIVIC, qui échange des messages en basant sur l’information géographique des noeuds (position). (...) / Each year in Europe, 1,300,000 vehicle accidents result in 1,700,000 personal injuries. The financial cost of vehicle accidents is evaluated at 160 billion Euros (approximately the same cost in the USA). VANET (Vehicular Ad-Hoc NETwork) is a key technology that can enable hazard alarming applications to reduce the accident number. In addition to improve the safety for drivers and passengers, VANET can contribute to many potential applications such as detecting and predicting traffic jams, auto-optimizing the traffic flow, and helping disabled passengers to access public transports.This thesis will present an embedded communication system dedicated to VANET especially for the safety-related applications. Our design mainly tries to achieve two requirements: as one can imagine, the embedded communication system for VANET requires extra effort to deal with the highly dynamic network topology caused by moving vehicles, thus to shorten the intra-node system latency and inter-node network delay is essential requirement for such embedded communication system. Besides, a fundamental requirement for any practical embedded system is resource-awareness. Although the embedded communication system on vehicles may gain better hardware supports, the characteristics of embedded hardware still have to cope with resource constraints in terms of QoS, memory, CPU and energy. The embedded communication system involves two major software components: a routing protocol called CIVIC (Communication Inter Véhicule Intelligente et Coopérative) and an embedded operating system called HEROS (Hybrid Event-driven and Real-time multitasking Operating System). The former is a quick reaction and low resource consumption geographic protocol for inter-vehicle message transmissions; and the latter controls the whole system and assures intra-node resource awareness. In addition, the system can use a localization software solution called LCD-GPS (Low Cost Differential GPS) to improve the accuracy of locations. The hardware platform is LiveNode (LImos Versatile Embedded wireless sensor NODE), which is a versatile wireless sensor node enabling to implement rapidly a prototype for different application domains. The communication system is based on the one-hop broadcast, thus it does not have a strict limitation on network specification. For the experiments only, the IEEE 802.15.4 standard is chosen as the underlying wireless access medium. The standard is well known as a low-power consumption standard requiring low-cost devices. Notice that the IEEE 802.15.4 standard is also the wireless access medium of 6LoWPAN. Although the embedded communication system is originally designed to meet the requirements of VANET, but its application domains are not limited to VANET. For example, another network which can use the embedded communication system is WSN (Wireless Sensor Network). CIVIC was used to implement different real-world projects such MOBI+ (intelligent urban transportation system) and EU-FP6 NeT-ADDED (precision agriculture). Both VANET and WSN are highly dynamic networks, but the causes of changing network topology are different: the former is because of the high-mobility feature of vehicles, and the latter is because of the fault of wireless sensors. Note that, although VANET and WSN are both commonly considered as the subset of MANET (Mobile Ad-hoc NETwork), they are actually quite different from the classical MANET, and the similarities and differences will be further explained in the thesis. The major contribution of my works relates to the CIVIC protocol, which routes messages based on the geographic information. The related works of the thesis will focus on the geographic routing techniques, problems and solutions, but other related techniques will also be addressed. Note that, although some related projects were investigated but their implementation and experiment aspects were not detailed. (...)

Chaque année en Europe, 1.300.000 accidents de la route ont comme conséquence 1.700.000 blessés. Le coût financier d'accidents de la route est évalué à 160 milliards d'euros (approximativement le même coût aux Etats-Unis). VANET (Vehicular Ad-hoc NETwork) est une des technologies clés qui peut permettre de réduire d'une façon significative le nombre d'accidents de la route (e.g. message d'urgence signalant la présence d'un obstacle ou d'un véhicule en cas de brouillard). En plus de l'amélioration de la sécurité et du confort des conducteurs et des passagers, VANET peut contribuer à beaucoup d'applications potentielles telles que la prévision et la détection d'embouteillages, la gestion d'infrastructure de système de transport urbain (e.g. système de transport intelligent multimodal) etc. Dans cette thèse, je présenterai un système embarqué dédié à la communication inter-véhicule particulièrement pour les applications sécuritaires de passagers et de conducteurs. Nos efforts de recherche et de développement sont centrés sur deux principaux objectifs : minimiser le temps de latence intra-noeud et le délai de communication inter-véhicule en prenant en compte le changement dynamique du VANET. De ce fait pour atteindre ces objectifs, des nouvelles approches (e.g. inter-couche 'Cross-layering') ont été explorées pour respecter les contraintes de ressource (QoS, mémoire, CPU et énergie de la communication inter-véhicule) d'un système embarqué à faible coût. Le système de communication embarqué proposé comporte deux composants logiciels principaux : un protocole de communication dénommé CIVIC (Communication Inter Véhicule Intelligente et Coopérative) et un système d'exploitation temps réel appelé HEROS (Hybrid Event-driven and Real-time multitasking Operating System). CIVIC est un protocole de communication géographique à faible consommation énergétique et à faible temps de latence (délai de communication). HEROS gère contextuellement l'ensemble du système (matériel et logiciel) en minimisant le temps de latence et la consommation des ressources (CPU et mémoire). En outre, le protocole de communication CIVIC est équipé d'un système de localisation LCD-GPS (Low Cost Differential GPS). Pour tester et valider les différentes techniques et théories, la plateforme matérielle LiveNode (LImos Versatile Embedded wireless sensor NODE) a été utilisée. En effet, la plateforme LiveNode permet de développer et de prototyper rapidement des applications dans différents domaines. Le protocole de communication CIVIC est basé sur la technique de 'broadcast' à un saut ; de ce fait il est indépendant de la spécificité du réseau. Pour les expérimentations, seule la norme d'IEEE 802.15.4 (ZigBee) a été choisie comme médium d'accès sans fil. Il est à noter que le médium d'accès sans fil ZigBee a été adopté comme le médium standard pour les réseaux de capteurs sans fil (RCSFs) et le standard 6LoWPAN ; car il est peu coûteux et peu gourmand en énergie. Bien que le protocole de communication à l'origine soit conçu pour répondre aux exigences de VANET, ses domaines d'application ne sont pas limités à VANET. Par exemple il a été utilisé dans différents projets tels que MOBI+ (système de transport urbain intelligent) et NeT-ADDED (projet européen FP6 : agriculture de précision). Les VANETs et les RCSFs sont les réseaux fortement dynamiques, mais les causes de changement topologique de réseau sont différentes : dans le réseau VANET, il est dû à la mobilité des véhicules, et dans le RCSF, il est dû aux pannes des noeuds sans fil. Il est à noter que le VANET et le RCSF sont généralement considérés comme un sous-ensemble du réseau MANET (réseau ad-hoc mobile). Cependant, ils sont réellement tout à fait différents du MANET classique, et leurs similitudes et différences seront expliquées en détail dans la thèse. La contribution principale de mes travaux est le protocole CIVIC, qui échange des messages en basant sur l'information géographique des noeuds (position). Les travaux relatifs de la thèse se concentreront sur les techniques, les problèmes et les solutions de routage géographique, mais d'autres techniques de routage seront également adressées. Quelques projets relatifs au protocole de communication ont été étudiés mais leur implémentation et les aspects d'expérimentation n'ont pas été détaillés. Enfin la thèse ne présente pas simplement les techniques et concepts adoptés, et les résultats de simulation, mais en outre, elle expliquera les aspects techniques importants pour la réalisation et l'expérimentation des différentes applications ainsi que les résultats concrets obtenus.

Networked control over wireless networks is of growing importance in many application domains such as industrial control, building automation and transportation systems. Wide deployment however, requires systematic design tools to enable efficient resource usage while guaranteeing close-loop control performance. The control system may be greatly affected by the inherent imperfections and limitations of the wireless medium and malfunction of system components. In this thesis, we make five important contributions that address these issues.  In the first contribution, we consider event- and self-triggered control and investigate how to efficiently tune and execute these paradigms for appropriate control performance. Communication strategies for aperiodic control are devised, where we jointly address the selection of medium-access control and scheduling policies. Experimental results show that the best trade-off is obtained by a hybrid scheme, combining event- and self-triggered control together with contention-based and contention-free medium access control. The second contribution proposes an event-based method to select between fast and slow periodic sampling rates. The approach is based on linear quadratic control and the event condition is a quadratic function of the system state. Numerical and experimental results show that this hybrid controller is able to reduce the average sampling rate in comparison to a traditional periodic controller, while achieving the same closed-loop control performance. In the third contribution, we develop compensation methods for out-of-order communications and time-varying delays using a game-theoretic minimax control framework. We devise a linear temporal coding strategy where the sensor combines the current and previous measurements into a single packet to be transmitted. An experimental evaluation is performed in a multi-hop networked control scenario with a routing layer vulnerability exploited by a malicious application. The experimental and numerical results show the advantages of the proposed compensation schemes. The fourth contribution proposes a distributed reconfiguration method for sensor and actuator networks. We consider systems where sensors and actuators cooperate to recover from faults. Reconfiguration is performed to achieve model-matching, while minimizing the steady-state estimation error covariance and a linear quadratic control cost. The reconfiguration scheme is implemented in a room heating testbed, and experimental results demonstrate the method's ability to automatically reconfigure the faulty system in a distributed and fast manner. The final contribution is a co-simulator, which combines the control system simulator Simulink with the wireless network simulator COOJA. The co-simulator integrates physical plant dynamics with realistic wireless network models and the actual embedded software running on the networked devices. Hence, it allows for the validation of the complete wireless networked control system, including the study of the interactions between software and hardware components. / <p>QC 20140929</p>