Performance analysis plays an increasingly important role in the design of embedded real-time systems. Time-to-market pressure in this domain is high while the available implementation technology is often pushed to its limit to minimize cost. This requires analysis of performance as early as possible in the life cycle. Simulation-based techniques are often not sufficiently productive. We present an alternative, analytical, approach based on Real-Time Calculus. Modular performance analysis is presented through a case study in which several candidate architectures are evaluated for a distributed in-car radio navigation system. The analysis is efficient due to the high abstraction level of the This work has been carried out as part of the boderc project under the responsibility of the Embedded Systems Institute.

The development of complex embedded control systems can be improved significantly by applying formal techniques from control engineering and software engineering. It is shown how these approaches can be combined to improve the design and analysis of high-tech systems, both in theory and practice. The semantics of the integration of two established rigorous techniques has been defined formally in this work. The strength of this integrated semantics is demonstrated by means of a significant industrial case study: the embedded control of a printer paper path, whereby the full development life-cycle from model to realization is covered. The resulting model-driven design approach fits the current engineering practice in industry and is both flexible and effective.

Overture is a community-based initiative that aims to develop a common open-source platform integrating a range of tools for constructing and analysing formal models of systems using VDM. The mission is to both provide an industrial-strength tool set for VDM and also to provide an environment that allows researchers and other stakeholders to experiment with modifications and extensions to the tools and language. This paper presents the current status and future vision of the Overture project.

Abstract. This paper presents initial results of research aimed at developing methods and tools for multidisciplinary collaborative development of dependable embedded systems. We focus on the construction and analysis by co-simulation of formal models that combine discrete-event specifications of computer-based controllers with continuous-time models of the environment with which they interact. Basic concepts of collaborative modelling and co-simulation are presented. A pragmatic realisation using the VDM and Bond Graph formalisms is described and illustrated by means of an example, which includes the modelling of both normal and faulty behaviour. Consideration of a larger-scale example from the personal transportation domain suggests the forms of support needed to explore the design space of collaborative models. Based on experience so far, challenges for future research in this area are identified.

The effective use of model-based formal methods in the development of complex embedded systems requires the integration of discrete-event models of controllers with continuous-time models of their environments. This paper proposes a new approach to the development of such combined models (co-models), in which an initial discrete-event model may include approximations of continuous-time behaviour that can subsequently be replaced by couplings to continuous-time models. An operational semantics of co-simulation allows the discrete and continuous models to run on their respective simulators and managed by a coordinating co-simulation engine. This permits the exploration of the composite co-model's behaviour in a range of operational scenarios. The approach has been realised using the Vienna Development Method (VDM) as the discrete-event formalism, and 20-sim as the continuous-time framework, and has been applied successfully to a case study based on the distributed controller for a personal transporter device.