How to solve ODEs in real-time HLA distributed simulation

In the context of the Research Platform for Embedded Systems Engineering (PRISE) Project, we are developing and maintaining a complete aircraft flight simulation using the High Level Architecture (HLA), an IEEE standard for distributed simulation. This complex distributed simulation is composed of different distributed HLA simulators (e.g., Flight Dynamics, Sensors), whose dynamic behaviors are implemented as Ordinary Differential Equations (ODEs). The resolution of these equations is done, locally for each simulator, by numerical integration with methods like Euler or Adams-Bashforth. The global behavior of this distributed simulation, where each component runs its own local resolution, is a key challenge. The main problem is to ensure the global simulation consistency and, in particular, the specific data flows between components with the correct temporal real-time behavior. This paper specifically addresses the problem of solving ODEs over an HLA distributed architecture and offers a complete study (specifications, implementation and validation) where several theoretical concepts and methods are discussed

Automatic Anomaly Detection over Sliding Windows: Grand Challenge

With the advances in the Internet of Things and rapid generation of vast amounts of data, there is an ever growing need for leveraging and evaluating event-based systems as a basis for building realtime data analytics applications. The ability to detect, analyze, and respond to abnormal patterns of events in a timely manner is as challenging as it is important. For instance, distributed processing environment might affect the required order of events, time-consuming computations might fail to scale, or delays of alarms might lead to unpredicted system behavior. The ACM DEBS Grand Challenge 2017 focuses on real-time anomaly detection for manufacturing equipments based on the observation of a stream of measurements generated by embedded digital and analogue sensors. In this paper, we present our solution to the challenge leveraging the Apache Flink stream processing framework and anomaly ordering based on sliding windows, and evaluate the performance in terms of event latency and throughput

Harmony An Architecture For Network Centric Heterogeneous Terrain Database Re-generation

Homogeneous proprietary online terrain databases are prolific. So also is the one directional generation and update process for these terrain databases. The existence of architectures and common ontologies that enable consistent and harmonious outcomes between distributed, multi-directional, heterogeneous terrain databases are lacking. Further due to technological change that empowers end-users, the expectations for immediate terrain database update are constantly increasing. As an example, a variety of incompatible synthetic environmental representations are used for military Modeling and Simulation applications. Regeneration and near-real-time update of compiled synthetic environments in a distributed, heterogeneous run time environment is an issue that is relevant to correlation of geospecific representations that are optimized for live, virtual, constructive and distributed simulation applications. Military systems of systems like the Future Combat Systems are emblematic of the regeneration challenge. The battlefields of the future will need constant updates of diverse synthetic representations of the real world environment. These updates will be driven by near real-time data from the battlefield as well as other constantly evolving intelligence and remote sensing sources. Since the Future Combat Systems will use embedded training, it will need to maintain a representation correlated with the actual battlefield as well as many other systems. To iv achieve this correlation, constant updates to the heterogeneous synthetic environment representations in the Future Combat Systems platforms will be required. An approach to overcoming the implicit bandwidth and communication limitations is to limit updates to changes only. Today’s traditional military Terrain Database (TDB) generation systems convert standard geographical source data products into many different target formats using what is refer to as pipeline flow paradigm. In the pipeline paradigm, TDBs are originally generated centrally upstream and flow downstream out to numerous divergent and distributed formats. In the pipeline paradigm, updates are centrally managed and distributed. This pipeline paradigm does not account for updates occurring on target formats and therefore such updates are not reflected upstream on the source data that originally generated the TDB. Since target format changes are not incorporated into the upstream geographical source data, adjacent streams of dependent target formats derived from the same geographical source data may not receive the changes either. The outcome of change in the pipeline TDB generation systems paradigm is correlation and interoperability errors between target formats as well as between the original upstream data source. An alternative paradigm that addresses data synchronization of geographical source data and target formats while accommodating bandwidth limitation is needed. This v dissertation proposes a “partial bi-directional TDB regeneration” paradigm, which envisions network based TDB updates between reliable partners. Partial bi-directional TDB regeneration is an approach that is very attractive as it reduces the amount of changes by only updating the affected target format data element. This research, presents an implementation of distributed, partial and bi-directional TDB regeneration through agent theory and ontologies over a network. Agent theory and ontologies are used to interpret data changes on external target formats and implement the necessary transformations on the Internal TDB generation system data elements to achieve consistency between all correlated representations. In this approach a variety of agents will exist and their behavior and knowledge will be customized based on ontologies that describe the target format. It is expected that such a system will provide a TDB generation paradigm that can address the implicit issues of: distribution, time, expertise, monetary, labor-constraints, and update frequency, while addressing the explicit issue of correlation between the external targets formats over time and at the same time reducing bandwidth requirements associated with traditional TDB generation system

Modellierung von Kommunikationssystemen zum Zweck der Systemanalyse und des Systementwurfs

Einen wesentlichen Beitrag zu Innovationen und Weiterentwicklungen in der Automobilindustrie leisten elektronische Komponenten. Der funktionale Wachstum in den Bereichen Sicherheit, Komfort und Fahrerassistenz führt zu einer Erhöhung der Komplexität. Neben der Anzahl der Komponenten steigert sich auch der Bedarf an Kooperation und Datenaustausch. Insbesondere by-wire- und Assistenzsysteme (Hochautomatisiertes Fahren) zeichnen sich durch hohe Anforderungen in den Bereichen Zuverlässigkeit, Datenkonsistenz, Fehlertoleranz und Ausfallsicherheit aus. Die Zusammenarbeit einzelner Steuergeräte fordert von der Kommunikationsstruktur neben hohen Datenraten auch Determinismus und Echtzeitverhalten. Die Entwicklung dieser komplexen verteilten Systeme profitiert durch modellbasierte Entwurfsprozesse. Der Nachweis von grundlegenden Systemeigenschaften mit dem Schwerpunkt Kommunikation soll bereits in frühen Entwurfsphasen mit Hilfe von ausführbaren Spezifikationen modell- und simulationsbasiert erfolgen. In dieser Arbeit wird ein Modellierungsansatz entworfen, welcher die typischen ereignis- und zeitgesteuerten Protokolle in der Domäne Automotive adressiert. Der Fokus liegt auf den Buszugriffsverfahren. Modelle auf unterschiedlichen Abstraktionsebenen werden am Beispiel von Controller Area Network (CAN) und FlexRay definiert und realisiert. Neben der reinen Kommunikation werden die angrenzenden Themenfelder Gateway (heterogene Kopplung) und Betriebssystem berücksichtigt. Detaillierte Modelle eignen sich zur Analyse spezifischer Protokolleigenschaften sowie zur Weiterentwicklung von Protokollfunktionen auf Modellebene. Mit abstrakteren Modellen lassen sich Leistungs- und Eigenschaftsanalysen von großen heterogenen Systemen durchführen. Echtzeitkommunikation, vernetzte Systeme und Anwendungsfelder für modellbasierte Entwurfsprozesse finden sich auch außerhalb des Automobilbereiches. Die Anwendung wird am Beispiel der Entwicklung und Optimierung eines komplexen verteilten Systems zur Steuerung einer Nanopositionier- und Nanomessmaschine demonstriert. Innerhalb des Entwicklungsprozesses werden Entwurf, Realisierung und Leistungsbewertung bezüglich der Architektur des Gesamtsystems, der Verteilung von Funktionen und der Realisierung einzelner Komponenten sowie applikationsspezifische Kommunikationsprotokolle betrachtet.Major innovations and improvements in the automotive industry base on the electronic components. The growing number of functionality in the areas safety, comfort and driver assistance lead to an increase of the complexity. Not only the number of components increase. Especially to realize complex assistance systems the cooperation and data exchange gets more important. In particular, by-wire and assistance systems (highly-automated driving) have high requirements on reliability, data consistency and safety. The cooperation of single control units to realize these complex functions require not only high data rates but also determinism and real-time behavior of the communication architecture. The development of these complex distributed systems benefits from model-based design processes. The verification and validation of system properties with a focus on communication should be possible in early design phases using model and simulation-based approaches based on executable specifications. In this thesis, a modeling approach is developed addressing the typical event-driven and time-triggered protocols in the automotive domain. Models on different abstraction levels are defined and implemented. The Controller Area Network (CAN) and FlexRay are used as examples. Beside the communication protocols some related topics: gateway-functionality (heterogeneous communication) and operating system. The developed detailed models are adequate for the analysis of specific protocol properties as well as the improvement of protocol functions on model level. More abstract models can be used to analyze the performance, real-time behavior and characteristics of large heterogeneous systems. Real-time communication, distributed embedded systems and model-based design processes are not limited to the automotive sector. Therefore the utilization of the modeling approach is demonstrated within the development and optimization of a distributed embedded system: a signal- and dataprocessing unit of a nanopositioning- and nanomeasuringmachine. The example covers most parts of the development process. Selected topics are the design of the system architecture, the distributed allocation of functionality, the realization of single components and the development of application specific communication protocols

Software for Embedded Control Systems

The research of our team deals with the realization of control schemes on digital computers. As such the emphasis is on embedded control software implementation. Applications are in the field of mechatronic devices, using a mechatronic design approach (the integrated and optimal design of a mechanical system and its embedded control system). The ultimate goal is to support the application developer (i.e. mechatronic design engineer) such that implementing control software according to ðo it the first time right¿ becomes business as usual

HLA high performance and real-time simulation studies with CERTI

Our work takes place in the context of the HLA standard and its application in real-time systems context. Indeed, current HLA standard is inadequate for taking into consideration the different constraints involved in real-time computer systems. Many works have been invested in order to provide real-time capabilities to Run Time Infrastructures (RTI). This paper describes our approach focusing on achieving hard real-time properties for HLA federations through a complete state of the art on the related domain. Our paper also proposes a global bottom up approach from basic hardware and software basic requirements to experimental tests for validation of distributed real-time simulation with CERTI

Verifying service continuity in a satellite reconfiguration procedure: application to a satellite

The paper discusses the use of the TURTLE UML profile to model and verify service continuity during dynamic reconfiguration of embedded software, and space-based telecommunication software in particular. TURTLE extends UML class diagrams with composition operators, and activity diagrams with temporal operators. Translating TURTLE to the formal description technique RT-LOTOS gives the profile a formal semantics and makes it possible to reuse verification techniques implemented by the RTL, the RT-LOTOS toolkit developed at LAAS-CNRS. The paper proposes a modeling and formal validation methodology based on TURTLE and RTL, and discusses its application to a payload software application in charge of an embedded packet switch. The paper demonstrates the benefits of using TURTLE to prove service continuity for dynamic reconfiguration of embedded software

CAN Fieldbus Communication in the CSP-based CT Library

In closed-loop control systems several realworld entities are simultaneously communicated to through a multitude of spatially distributed sensors and actuators. This intrinsic parallelism and complexity motivates implementing control software in the form of concurrent processes deployed on distributed hardware architectures. A CSP based occam-like architecture seems to be the most convenient for such a purpose. Many, often conflicting, requirements make design and implementation of distributed real-time control systems an extremely difficult task. The scope of this paper is limited to achieving safe and real-time communication over a CAN fieldbus for an\ud existing CSP-based framework

Federated Embedded Systems – a review of the literature in related fields

This report is concerned with the vision of smart interconnected objects, a vision that has attracted much attention lately. In this paper, embedded, interconnected, open, and heterogeneous control systems are in focus, formally referred to as Federated Embedded Systems. To place FES into a context, a review of some related research directions is presented. This review includes such concepts as systems of systems, cyber-physical systems, ubiquitous computing, internet of things, and multi-agent systems. Interestingly, the reviewed fields seem to overlap with each other in an increasing number of ways