Abstract not found

Depending on the physical structuring of large distributed safety-critical real-time systems, one can distinguish federated and integrated system architectures. This paper investigates the communication services of an integrated system architecture, which combines the complexity management advantages of federated systems with the functional integration and hardware benefits of an integrated approach. A major challenge is the need to accommodate the communication services to the different types of integrated application subsystems that range from ultradependable control applications (e.g., an x-by-wire system) to non safety-critical applications such as multimedia or comfort systems. In particular, the encapsulation of the communication activities of different application subsystems is required not only to prevent error propagation from non safety-critical application subsystems to higher levels of criticality, but also to facilitate complexity management and permit independent development activities.

Cyber-Physical Systems (CPS) are integrations of computation and physical processes. Embedded computers and networks monitor and control the physical processes, usually with feedback loops where physical processes affect computations and vice versa. The economic and societal potential of such systems is vastly greater than what has been realized, and major investments are being made worldwide to develop the technology. There are considerable challenges, particularly because the physical components of such systems introduce safety and reliability requirements qualitatively different from those in generalpurpose computing. Moreover, physical components are qualitatively different from object-oriented software components. Standard abstractions based on method calls and threads do not work. This paper examines the challenges in designing such systems, and in particular raises the question of whether today’s computing and networking technologies provide an adequate foundation for CPS. It concludes that it will not be sufficient to improve design processes, raise the level of abstraction, or verify (formally or otherwise) designs that are built on today’s abstractions. To realize the full potential of CPS, we will have to rebuild computing and networking abstractions. These abstractions will have to embrace physical dynamics and computation in a unified way. 1

The steady increase in electronics in automotive systems in order to meet the customers expectation of a cars functionality has led to the development of integrated architectures, as already partly deployed in avionics. Integrated architectures overcome the "1 Function -- 1 Electronic Control Unit (ECU)" design philosophy by providing an infrastructure that allows the sharing of ECUs between multiple applications. As a consequence, integrated systems promise massive cost savings through the reduction of resource duplication. In addition, integrated systems permit an optimal interplay of application subsystems, reliability improvements with respect to wiring and connectors, and overcome limitations for spare components and redundancy management.

Depending on the physical structuring of large distributed safety-critical real-time systems, one can distinguish federated and integrated system architectures. This paper describes an integrated system architecture, which combines the complexity management advantages of federated systems with the functional integration and hardware benefits of an integrated approach. In order to control complexity, the overall functionality is divided into a set of application subsystems, each with dedicated architectural communication services, allowing developers to act as if they were building an application for a federated architecture. The introduced architecture builds upon the validated services of a time-triggered core architecture, which provides a physical network as a shared resource for the communication activities of more than one application subsystem. The communication resources are encapsulated and multiplexed between application subsystems. In analogy, encapsulated partitions are used to share node computers among software modules of multiple application subsystems. Architectural encapsulation mechanisms ensure that the assumptions and abstractions performed in the functional system structuring also hold after combining the different subsystems on the target platform.

Keywords: The DECOS architecture is an integrated architecture that builds upon the validated services of a timetriggered network, which serves as a shared resource for the communication activities of more than one application subsystem. In addition, encapsulated partitions are used to share the computational resources of Electronic Control Units (ECUs) among software modules of multiple application subsystems. This paper investigates the benefits of the DECOS architecture as an electronic infrastructure for future car generations. The shift to an integrated architecture will result in quantifiable cost reductions in the areas of system hardware cost and system development. In the paper we present a current federated Fiat car E/E architecture and discuss a possible mapping to an integrated solution based on the DECOS architecture. The proposed architecture provides a foundation for mixed criticality integration with both safety-critical and non safety-critical subsystems. In particular, this architecture supports applications up to the highest criticality classes (10 −9 failures per hour), thereby taking into account the emerging dependability requirements of by-wire functionality in the automotive industry. real-time systems, system architectures, automotive electronics, communication networks, legacy systems, dependability, component-based integration

This paper addresses component-based approach for embedded systems. Due to the specific characteristics of embedded systems the general-purpose component technologies such as COM, .NET, or EJB have not been the most appropriate choices for their development. Although attractive, component-based approach has not been successful in this domain as in other domains. However in recent years the interest for component-based approach in embedded systems increases. The experience has shown that existing technologies cannot be used, or at least used directly. On the other hand an increasing understanding of principles of component-based approach makes it possible to utilize these principles in implementation of different component-based models, more appropriate for embedded systems. This paper gives an overview of basic characteristics of embedded systems, their requirements and constraints, and the implications to component models for these systems.

this paper is to provide an introduction to the time-triggered approach. The remainder of this paper is structured as follows: Section 2 introduces the concept of a sparse time base, the notion of state, real-time entities and real-time images, and discusses the di#erence between state and event information. Section 3 explains some principles of time-triggered systems such as a temporal firewall, composability, and dependability. Section 4 discusses properties of a time-triggered communication such as synchrony, common communication schedule, and clock synchronization. The paper is concluded in section 5. 2 Related Concepts 2.1 Sparse Time For most real time applications it is su#cient to model time according to Newtonian physics [1]. Hence, time progresses along a dense timeline, consisting of an infinite set of instants from past to future. Logical clocks, as introduced by Lamport in [2], usually are imprecise whenever physical time is essential. However, when global physical time is used to deduce causality of distributed events, it is necessary to synchronize the local clocks precisely

The increasing use of electronics in the automotive and avionic domain has lead to dramatic improvements with respect to functionality, safety, and cost. However, with this growth of electronics the likelihood of failures due to faults originating from electronic equipment also increases. In order to tackle prevalent diagnostic problems such as the reduction of the fault-not-found ratio, a maintenance-oriented fault model is needed that serves as the basis for the classification of experienced failures.

Reduced time–to–market in spite of increasing the system’s functionality, reuse of software on different hardware platforms, and the demand for performing validation activities earlier in the development phase raise the need for revising the state–of–the–art development methodologies for distributed embedded systems. The Model Driven Architecture is a design methodology addressing these emerging requirements. Developing embedded systems according to this model-based paradigm requires a platform-independent representation of the functionality of the application as well as a precise model of the targeted hardware platform. In this paper we introduce a meta-model for capturing the resources of hardware platforms realizing the DECOS architecture, which is an integrated time-triggered architecture aimed at the development of distributed embedded systems. Furthermore, we present a tool chain based on this meta-model that speeds up the modeling process and reduces the likelihood of human errors by facilitating the reuse of hardware building blocks from libraries. 1.