CSP channels for CAN-bus connected embedded control systems

Closed loop control system typically contains multitude of sensors and actuators operated simultaneously. So they are parallel and distributed in its essence. But when mapping this parallelism to software, lot of obstacles concerning multithreading communication and synchronization issues arise. To overcome this problem, the CT kernel/library based on CSP algebra has been developed. This project (TES.5410) is about developing communication extension to the CT library to make it applicable in distributed systems. Since the library is tailored for control systems, properties and requirements of control systems are taken into special consideration. Applicability of existing middleware solutions is examined. A comparison of applicable fieldbus protocols is done in order to determine most suitable ones and CAN fieldbus is chosen to be first fieldbus used. Brief overview of CSP and existing CSP based libraries is given. Middleware architecture is proposed along with few novel ideas

Modeling a distributed Heterogeneous Communication System using Parametric Timed Automata

In this report, we study the application of the Parametric Timed Automata(PTA) tool to a concrete case of a distributed Heterogeneous Communication System (HCS). The description and requirements of HCS are presented and the system modeling is explained carefully. The system models are developed in UPPAAL and validated by different test cases. Part of the system models are then converted into parametric timed automata and the schedulability checking is run to produce the schedulability regions

Simulation-Based Fault Injection as a Verification Oracle for the Engineering of Time-Triggered Ethernet networks

TTEthernet (TTE) is considered for use as high-speed backbone in the avionics of next-generation orbital space launchers. Given the key role of communication in launchers, the OEM must acquire a precise understanding of TTE’s functioning and its performances in nominal and error conditions. This holds especially true for the clock synchronization algorithm, the cornerstone of time-triggered communication in TTE, which involves complex distributed algorithms. In this study, we use both an experimental platform and fault-injection on a simulation model to gain quantified insights in these questions. We first describe a fine-grained simulation model of TTE model and discuss how it has been validated against communication traces recorded on the TTE platform. We then present experiments that evaluate the accuracy of the clock synchronization in TTE in the fault-free case as well as considering permanent link failure and transient transmission errors. Finally, we discuss what we have learned during the project in terms of development process and programming language support for complex simulation models used in the design of critical systems

Model-based WCET Analysis with Invariants

The integration of worst case execution time (WCET) analysis in model-based designs allows timing problems to be discovered in the early phases of development, when they are less expensive to correct than in later phases. In this paper, we show how model-based WCET analysis can improve timing calculations compared to program-based WCET analysis. The models are described by hierarchical state machines with concurrency, probabilistic transition, stochastic transitions, costs/rewards attached to states and transitions, and invariants attached to states. In these models, user-specified invariants serve to check the correctness of designs by restricting allowed state configurations. Our contribution is to use invariants additionally to determine transition combinations (paths) that can be eliminated from the WCET analysis, with the help of a decision procedure, thus making the analysis more precise. The assembly code of transitions for a specific target is generated and execution time for that code calculated. From the model, a probabilistic timed automaton (PTA) or Markov decision process (MDP) can be created. On that model, execution times of transitions are calculated as costs

Modeling and Analysis of Mixed Synchronous/Asynchronous Systems

Practical safety-critical distributed systems must integrate safety critical and non-critical data in a common platform. Safety critical systems almost always consist of isochronous components that have synchronous or asynchronous interface with other components. Many of these systems also support a mix of synchronous and asynchronous interfaces. This report presents a study on the modeling and analysis of asynchronous, synchronous, and mixed synchronous/asynchronous systems. We build on the SAE Architecture Analysis and Design Language (AADL) to capture architectures for analysis. We present preliminary work targeted to capture mixed low- and high-criticality data, as well as real-time properties in a common Model of Computation (MoC). An abstract, but representative, test specimen system was created as the system to be modeled

An Energy-autonomous Wireless Sensor Network Development Platform

Internet-of-things enabled applications are increasingly popular and are expected to spread even more in the next few years. Energy efficiency is fundamental to support the widespread use of such systems. This paper presents a practical framework for the development and the evaluation of low-power Wireless Sensor Networks equipped with energy harvesting, aiming at energy-autonomous applications. An experimental case study demonstrates the capabilities of the solution

A Modular Approach for Synchronized Wireless Multimodal Multisensor Data Acquisition in Highly Dynamic Social Settings

Existing data acquisition literature for human behavior research provides wired solutions, mainly for controlled laboratory setups. In uncontrolled free-standing conversation settings, where participants are free to walk around, these solutions are unsuitable. While wireless solutions are employed in the broadcasting industry, they can be prohibitively expensive. In this work, we propose a modular and cost-effective wireless approach for synchronized multisensor data acquisition of social human behavior. Our core idea involves a cost-accuracy trade-off by using Network Time Protocol (NTP) as a source reference for all sensors. While commonly used as a reference in ubiquitous computing, NTP is widely considered to be insufficiently accurate as a reference for video applications, where Precision Time Protocol (PTP) or Global Positioning System (GPS) based references are preferred. We argue and show, however, that the latency introduced by using NTP as a source reference is adequate for human behavior research, and the subsequent cost and modularity benefits are a desirable trade-off for applications in this domain. We also describe one instantiation of the approach deployed in a real-world experiment to demonstrate the practicality of our setup in-the-wild.Comment: 9 pages, 8 figures, Proceedings of the 28th ACM International Conference on Multimedia (MM '20), October 12--16, 2020, Seattle, WA, USA. First two authors contributed equall

Property driven verification framework: application to real time property for UML MARTE software design

Les techniques formelles de la famille « vérification de modèles » (« model checking ») se heurtent au problème de l’explosion combinatoire. Ceci limite les perspectives d’exploitation dans des projets industriels. Ce problème est provoqué par la combinatoire dans la construction de l’espace des états possibles durant l’exécution des systèmes modélisés. Le nombre d’états pour des modèles de systèmes industriels réalistes dépasse régulièrement les capacités des ressources disponibles en calcul et stockage. Cette thèse défend l’idée qu’il est possible de réduire cette combinatoire en spécialisant les outils pour des familles de propriétés. Elle propose puis valide expérimentalement un ensemble de méthodes pour le développement de ce type d’outils en suivant une approche guidée par les propriétés appliquée au contexte temps réel. Il s’agit donc de construire des outils d’analyse performants pour des propriétés temps réel qui soient exploitables pour des modèles industriels de taille réaliste. Les langages considérés sont, d’une part UML étendu par le profil MARTE pour la modélisation par les utilisateurs, et d’autre part les réseaux de Petri temporisés comme support pour la vérification. Les propositions sont validées sur un cas d’étude industriel réaliste issu du monde avionique : l’étude de la latence et la fraicheur des données dans un système de gestion des alarmes exploitant les technologies d’Avionique Modulaire Intégrée. Ces propositions ont été mise en oeuvre comme une boite à outils qui intègre les cinq contributions suivantes: la définition de la sémantique d’exécution spécifiques aux propriétés temps réel pour les modèles d’architecture et de comportement spécifiés en UML/MARTE; la spécification des exigences temps réel en s’appuyant sur un ensemble de patrons de vérification atomiques dédiés aux propriété temps réel; une méthode itérative d’analyse à base d’observateurs pour des réseaux de Petri temporisés; des techniques de réduction de l’espace d’états spécifiques aux propriétés temps réel pour des Réseaux de Petri temporisés; une approche pour l’analyse des erreurs détectées par « vérification des modèles » en s’appuyant sur des idées inspirées de la « fouille de données » (« data mining »). ABSTRACT : Automatic formal verification such as model checking faces the combinatorial explosion issue. This limits its application in indus- trial projects. This issue is caused by the explosion of the number of states during system’s execution , as it may easily exceed the amount of available computing or storage resources. This thesis designs and experiments a set of methods for the development of scalable verification based on the property-driven approach. We propose efficient approaches based on model checking to verify real-time requirements expressed in large scale UML-MARTE real-time system designs. We rely on the UML and its profile MARTE as the end-user modeling language, and on the Time Petri Net (TPN) as the verification language. The main contribution of this thesis is the design and implementation of a property-driven verification prototype toolset dedicated to real-time properties verification for UML-MARTE real-time software designs. We validate this toolset using an avionic use case and its user requirements. The whole prototype toolset includes five contributions: definition of real-time property specific execution semantics for UML-MARTE architecture and behavior models; specification of real- time requirements relying on a set of verification dedicated atomic real- time property patterns; real-time property specific observer-based model checking approach in TPN; real-time property specific state space reduction approach for TPN; and fault localization approach in model checking