Paul De Meulenaere

Incorporation of AUTOSAR in an Embedded Systems Development Process: A Case Study

AUTOSAR, the Automotive Open System Architecture, is growing to an accepted industrial standard for the development of automotive embedded software. The AUTOSAR design method describes a software development process starting at the architectural design up to the deployment of the developed software on embedded controllers. Since most companies already have their own system development process, the introduction of AUTOSAR will have a direct impact on these processes. In this paper we will demonstrate the integration of AUTOSAR in a system development process that is similar to an industrial development process. This process is validated by means of an ABS case study. It is shown that introducing AUTOSAR has a relative small impact on the existing system development process.

Ontological reasoning for consistency in the design of cyber-physical systems

The design of Cyber-Physical Systems (CPS) involves a multitude of stakeholders. Each of these stakeholders has a specific view on the system under design. Unfortunately, when designers create artefacts in their different views in a concurrent manner, the integration of the different views may reveal inconsistencies. This leads to time consuming, iterative design processes where inconsistencies are resolved, in turn possibly creating new ones. It is hence necessary to reason explicitly about the view-specific properties that depend on, and influence properties of other views. This enables consistency during integration and reduces the development time and effort. In this paper we formalise the interrelationships between the different views, in the context of different design processes, to allow designers to meaningfully and efficiently manage inconsistencies. Our formalisation introduces ontological domain properties and their relations as the link between the view-specific properties used by the stakeholders. Thus, our approach combines the state of the art of Model-Based Systems Engineering (MBSE) and Semantic Web. The relevance of this approach is demonstrated by means of a motivating example.

DEVS for AUTOSAR-based system deployment modeling and simulation:

AUTOSAR (AUTomotive Open System ARchitecture) is an open and standardized automotive software architecture, developed by automobile manufacturers, suppliers, and tool developers. Its design is a direct consequence of the increasingly important role played by software in vehicles. As design choices during the software deployment phase have a large impact on the behavior of the system, designers need to explore various trade-offs. Examples of such design choices are the mapping of software components to processors, the priorities of tasks and messages, and buffer allocation. In this paper, we evaluate the appropriateness of DEVS, the Discrete-Event System specification, for modeling and subsequent performance evaluation of AUTOSAR-based systems. Moreover, a DEVS simulation model is constructed for AUTOSAR-based electronic control units connected by a communication bus. To aid developers in evaluating a deployment solution, the simulation model is extended with co-simulation with a plant and environment model, evaluation at different levels of detail, and fault injection. Finally, we examine how the simulation model supports the relationship between the supplier and the original equipment manufacturer in the automotive industry. We demonstrate and validate our work by means of a power window case study.

Ontological Reasoning as an Enabler of Contract-Based Co-design

Because of the combination of computational, networking and physical artifacts, different engineering disciplines are involved in the design of a Cyber-Physical System (CPS). This multidisciplinary approach leads to different, often contradicting, views on the system under design which in the end might lead to inconsistencies between domain specific properties. Contract-Based Design (CBD) aims to prevent these contradictions by defining possible conflicting properties in a contract. These contracts consist of a set of pre- and postconditions.

DASH7 Alliance Protocol in Monitoring Applications

In this paper we introduce important aspects of the recently published DASH7 Alliance Protocol v1.0 specification for wireless sensor and actuator networks. The main contribution of this paper is the discussion of the different communication schemes and the accompanying trade-offs which can be used when designing a DASH7 network. Finally, we describe two practical use cases as examples of how DASH7 can be used to efficiently solve specific problems as well as the hardware developed that uses energy harvesting.

Powerwindow: a Multi-component TACLeBench Benchmark for Timing Analysis

Timing analysis is used to extract the timing properties of a system. Different timing analysis techniques and tools have been developed over the past decades. Well-rounded benchmark suites are in a high demand for the evaluation of those techniques and tools. TACLeBench is aiming to provide a benchmark suite to fulfil the requirement. It is not only limited to single-core systems but also will be replenished with complex benchmarks for multi-core systems. In this paper, we propose a multi-component benchmark which can be easily converted to benchmarks for single-core, parallel, distributed or even multi-core systems without fundamental changes.

Managing Heterogeneity in Model-Based Systems Engineering of Cyber-Physical Systems

Model-based Systems Engineering plays a pivotal role in the design of distributed embedded systems by enabling early virtual integration of the different parts of the system. Traditionally, the system model is composed of subsystem models at the same level of abstraction and with one particular view. However, in some cases the system model may comprise sub-system models at different levels of abstraction. Integration of these different abstraction level models imposes some important drawbacks which hinder the overall system simulations. These drawbacks need to be addressed to facilitate the simulation of systems composed with multi-level subsystem models. In this paper we report on modelling techniques for embedded and distributed systems to deal with this heterogeneity. We describe a methodology to (semi-)automatically generate an executable multi-level system simulation model starting from an abstract system architecture of the system. A platooning system example is used to demonstrate the new modelling techniques.

Semantic adaptation for FMI co-simulation with hierarchical simulators

Model-based design can shorten the development time of complex systems by the use of simulation techniques. However, it can be hard to simulate the system as a whole if it is developed in a concurrent fashion by multiple and specialized teams. Co-simulation, with the support of the Functional Mockup Interface (FMI) Standard, is proposed as a way to promote tool interoperability while protecting the intellectual property of subsystems. The standard allows uniform communication between subsystem simulators, but does not state how the inputs and outputs should be interpreted, nor how the subsystems should interact correctly. Semantic adaptations can be quickly made to correct the interactions with subsystem simulators that were produced with different assumptions, and avoid changing those subsystems, their simulators, or the orchestration algorithm that computes the co-simulation. In this work, we explore how to describe common adaptations and what their meaning is in the context of FMI co-simulation. The result is a sound language that enables the implementation of adaptations with minimal effort. A distinct feature is that it describes adaptations for groups of interconnected subsystem simulators in the same way as for a single simulator, and the implementation is itself a simulator, thanks to a sound definition of hierarchical co-simulation. This work paves the way for research into the correct combination and interfacing of different adaptations.

Model-Based Physical System Deployment on Embedded Targets with Contract-Based Design

Designing model-based physical systems has growing demand in consequence of increasing system complexity. In particular, observers/estimators are extensively used for the applications requiring state or disturbance estimation. Designing and deploying such numerically intensive physical systems onto embedded targets is a challenging task that requires codesign among various stakeholders from different technical backgrounds.The most important challenge is to obtain a numeric behavior of the estimator from an embedded target, that is able to represent the physical system states/disturbance with an acceptable error margin. Moreover, this error margin needs to be decided by the stakeholders, which makes the overall embedded deployment a co-design problem. The main contribution of this paper is to investigate the cause of the estimation error of an estimator that is deployed to embedded targets. This error is studied in the form of precision loss in addition to the error originating in the decreasing estimator measurement frequency for the embedded targets. We propose Assume-Guarantee (A/G) contracts to reconcile the viewpoints of the stakeholders, who reside at different abstraction levels. The feasibility of the proposed physical system deployment method is presented by utilizing a model-based virtual sensor estimator deployment for embedded targets as a case study.

Migrating from a Proprietary RTOS to the OSEK Standard Using a Wrapper

The drive towards standardization in the automotive sector puts a lot of pressure on software suppliers to comply with standards such as OSEK and AUTOSAR. However, many of these suppliers have a vested interest in proprietary software and are seeking ways to migrate their existing code base to comply with these standards. This paper reports on a feasibility study to migrate an automotive off-highway application to the OSEK-OS using a wrapper around the proprietary real-time operating system (RTOS). Besides investigating whether this is feasible, we also assess the performance impact in terms of computation time and memory consumption, as this is critically important for real-time systems. Finally some pitfalls are given when porting a given application to OSEK-compliant RTOS. As such, we evaluate the typical trade-offs one has to make when adopting an incremental migration strategy towards a standard compliant interface.