Joachim Denil

A characterization of integrated multi-view modeling in the context of embedded and cyber-physical systems

Embedded systems, with their tight technology integration, and multiple requirements and stakeholders, are characterized by tightly interrelated processes, information and tools. Embedded systems will as a consequence be described by multiple, heterogeneous and interrelated descriptions such as for example requirements documents, design and analysis models, software and hardware descriptions. We refer to a system designed this way as a multi-view (MV) system. The main contribution of this paper is a characterization of model-based approaches to MV systems. The characterization takes three main perspectives for the relations between viewpoints: semantic relations (content), relations over time (process), and manipulation of views (operations). We complement these perspectives by investigating MV system challenges and by a survey of related approaches. The characterization aims to provide a basis for a better understanding, design and implementation of MV systems, and thereby to overcome the current fragmented points of view on integrated multi-view modeling (MVM).

FTG+PM: An Integrated Framework for Investigating Model Transformation Chains

In this paper, we describe our ongoing work on model transformation chains. Model transformation chains refer to the sequences of model transformations in Model Driven Engineering (MDE). The transformations represent and formalise typical model/software engineering activities, and their chaining is the natural composition of such activities. Model transformation chains found in industrial practice vary widely, depending on the specific domain they are used in. By explicitly modelling development activities, these activities can be analysed and the MDE process may be improved. As a step towards such analyses, we propose an integrated framework to describe all the artifacts involved in model transformation chains, as well as the means to execute “enact” those chains. We describe the Formalism Transformation Graph + Process Model (FTG+PM) which is at the heart of our framework in detail.

The FTG+PM framework for multi-paradigm modelling: an automotive case study

In recent years, many new concepts, methodologies, and tools have emerged, which have made Model Driven Engineering (MDE) more usable, precise and automated. We have earlier proposed a conceptual framework, FTG+PM, that acts as a guide for carrying out model transformations, and as a basis for unifying key MDE practices, namely multi-paradigm modelling, meta-modelling, and model transformation. The FTG+PM consists of the Formalism Transformation Graph (FTG) and its complement, the Process Model (PM), and charts activities in the MDE lifecycle such as requirements development, domain-specific design, verification, simulation, analysis, calibration, deployment, code generation, execution, etc. In this paper, we apply the FTG+PM approach to a case study of a power window in the automotive domain. We present a FTG+PM model for the automotive domain, and describe the MDE process we applied based on our experiences with the power window system.

Search-Based Model Optimization Using Model Transformations

Design-Space Exploration (DSE) and optimization look for a suitable and optimal candidate solution to a problem, with respect to a set of quality criteria, by searching through a space of possible solution designs. Search-Based Optimization (SBO) is a well-known technique for design-space exploration and optimization. Model-Driven Engineering (MDE) offers many benefits for creating a general approach to SBO, through a suitable problem representation. In MDE, model transformation is the preferred technique to manipulate models. The challenge thus lies in adapting model transformations to perform SBO tasks. In this paper, we demonstrate that multiple SBO techniques are easily incorporated into MDE. Through a non-trivial example of electrical circuit generation, we show how this approach can be applied, how it enables simple switching between different SBO approaches, and integrates domain knowledge, all within the modeling paradigm.

Towards domain-specific property languages: the ProMoBox approach

Domain-specific modeling (DSM) is one major building block of model-driven engineering. By moving from the solution space to the problem space, systems are designed by domain experts. The benefits of DSM are not unique to the design of systems, the specification and verification of desired properties of the designed systems by the help of DSM seems the next logical step. However, this latter aspect is often neglected by DSM approaches or only supported by translating design models to formal representations on which temporal properties are defined and evaluated. Obviously, this transition to the solution space is in contradiction with DSM. To shift the specification and verification tasks to the DSM level, we extend traditional Domain-Specific Modeling Languages (DSMLs) for design with ProMoBox, a language family comprising three DSMLs covering design, property specification, and verification results. By using ProMoBox, temporal properties can be described for finite-state systems and verified by the SPIN model checker, by compiling them to Promela and Linear Temporal Logic (LTL). For specifying properties we present a DSML that is based on Dwyers specification patterns and mash it up with adapted versions of the design DSML to formulate structural patterns. In particular, we show that a ProMoBox can be generated from a single root meta-model and we demonstrate our approach with a ProMoBox for statecharts.

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.

Automated testing support for reactive domain-specific modelling languages

Domain-specific modelling languages (DSML) enable domain users to model systems in their problem domain, using concepts and notations they are familiar with. The process of domain-specific modelling (DSM) consists of two stages: a language engineering stage where a DSML is created, and a system modelling stage where the DSML is used. Because techniques such as metamodelling and model transformation allow for a efficient creation of DSMLs, and using DSMLs significantly increases productivity, DSM is very suitable for early prototyping. Many systems that are modelled using DSMLs are reactive, meaning that during their execution, they respond to external input. Because of the complexity of input and response behaviour of reactive systems, it is desirable to test models as early as possible. However, while dedicated testing support for specific DSMLs has been provided, no systematic support exists for testing DSML models according to DSM principles. In this paper, we introduce a technique to automatically generate a domain-specific testing framework from an annotated DSML definition. In our approach, the DSML definition consists of a metamodel, a concrete syntax definition and operational semantics described as a schedule of graph rewrite rules, thus covering a large class of DSMLs. Currently, DSMLs with deterministic behaviour are supported, but we provide an outlook to other (nondeterministic, real-time or continuous-time) DSMLs. We illustrate the approach with a DSML for describing an elevator controller. We evaluate the approach and conclude that compared to the state-of-the-art, our testing support is significantly less costly, and similar or better (according to DSM principles) testing support is achieved. Additionally, the generative nature of the approach makes testing support for DSMLs less error-prone while catering the need for early testing.

Testing IoT systems using a hybrid simulation based testing approach

This paper presents an extensive overview of the challenges that arise when testing large IoT applications at the system level. In order do that we start from analyzing behavior of local entities such as IoT devices or people interacting with the IoT system. The interactions of these local entities eventually leads to an emergent behavior. Both the emergent behavior and the local behavior need to be taken into account when testing IoT systems. Therefore, we present a novel hybrid simulation based testing approach that is able to effectively facilitate interactions of these local entities. Furthermore, we introduce various solutions to the challenges that arise when implementing this hybrid methodology. These challenges are mainly related to the IoT development pipeline, synchronization between real-life and simulation environment and the scalability constraints of modern simulation techniques.

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.