[Show abstract][Hide abstract] ABSTRACT: Hard real-time operating systems have been mostly designed for uniprocessors. Driven by the high computational demand of real-time systems, these operating systems have been re-designed for multiprocessors. Researchers have been identifying issues that affect the predictability of multiprocessor hard real-time systems. These sources of unpredictability make it difficult to accurately predict safe and tight worst-case execution time bounds of real-time tasks. As a result, the performance of multiprocessor hard real-time systems is compromised. In this paper, we present a middleware architecture that aims to provide predictability and high efficiency for multiprocessor hard real-time systems. The middleware supports hybrid hard real-time tasks, which are adaptive hard real-time services that intend to ensure predictability and performance. We also present a prototype of this architecture. Moreover, we identify and discuss issues that affect the predictability and performance of multiprocessor hard real-time systems.
[Show abstract][Hide abstract] ABSTRACT: This paper describes the design and development of a proof-of-concept platooning application, which operates in a mobile and dynamic environment and makes use of architectural and middleware solutions that were proposed in the scope of the HIDENETS project. With this application it is possible to demonstrate the practical feasibility of a hybrid system architecture, with realms of operation with distinct synchrony properties, and the benefits of adopting such architecture. In particular, we show that it is possible to improve the performance and behavior of the platooning application, which operates over an intrinsically uncertain environment (due to mobility and wireless communication), and still secure fundamental safety-critical requirements.
[Show abstract][Hide abstract] ABSTRACT: Building distributed embedded systems in wireless and mobile environments is more challenging than if fixed network infrastructures
can be used. One of the main issues is the increased uncertainty and lack of reliability caused by interferences and fading
in the communication, dynamic topologies, and so on.
When predictability is an important requirement, then the uncertainties created by wireless networks become a major concern.
The problem may be even more stringent if some safety critical requirements are also involved.
In this paper we discuss the use of hybrid models and architectural hybridization as one of the possible alternatives to deal
with the intrinsic uncertainties of wireless and mobile environments in the design of distributed embedded systems. In particular,
we consider the case of safety-critical applications in the automotive domain, which must always operate correctly in spite
of the existing uncertainties. We provide the guidelines and a generic architecture for the development of these applications
in the considered hybrid systems. We also refer to interface issues and describe a programming model that is “hybridization-aware”.
Finally, we illustrate the ideas and the approach presented in the paper using a practical application example.