Issues of Hierarchical Heterogeneous Modeling in Component Reusability

International audienceHeterogeneous systems are systems that obey different functioning laws. For instance, during the design of embedded systems, it is generally necessary to study both the controller and the environment that it controls, these two subsystems being clearly different in nature. Moreover, data processing applications are also increasingly heterogeneous, mixing different technical domains such as telecommunications, man-machine interface, analog and digital electronic, signal processing algorithms. To combine these different technology domains, modeling languages and platforms generally use a hierarchical approach. This paper highlights how the hierarchy of the model and the changes of model of computation are coupled and why this coupling forbids the use of components that have inputs or outputs that obey different models of computation. In addition, this paper shows that what happens when data crosses the boundary between two domains depends on the modeling environment and it gives some means of managing component in the same level of the hierarchy

An Approach of Domain Polymorph Component Design

International audienceHeterogeneous modelling and design tools allow the design of software systems using several computation models. The designed system is built by assembling components that obey a computation model. The internal behavior of a component is specified either in some programming language or by assembling sub-components that obey a possibly different computation model. When the same behavior is used in several computation models, it must be implemented in as many components as there are models, or, if the design platform supports it, it may be implemented as a generic component. Model-specific components require the recoding of the same core behavior several times, and generic components may not take model- specific features into account. In this paper, we introduce the notion of domain-polymorph component. Such a component is able to adapt a core behavior to the semantics of several computation models. The core behavior is implemented only once and is automatically adapted to the semantics of different computation models. Domain-polymorph components can be chosen by a system designer and integrated in a computation model: they will benefit from an appropriate execution environment and their semantics will be adapted to the host model. The designer will have the choice for several parameters of the adaptation. Contrary to generic components, such components adapt their behavior to the host model instead of letting the host model interpret their generic behavior. We also present an implementation of the concept of domain-polymorph component in the Ptolemy~II framework

Flat Heterogeneous Modeling

International audienceMost heterogeneous modeling environments allow only one model of computation at each hierarchical level of a model. The consequences are that (1) the transformations that occur at the boundary of two models of computation depend on the modeling tool and (2) the hierarchical structure of the model is perturbed by layers introduced to allow changes of model of computation. We introduce "heterogeneous interface components" to allow flat heterogeneous modeling. Such components have inputs and outputs that obey different models of computation. We present an execution model that allows the use of these components with any model of computation

Le paradigme acteur dans la modélisation des systèmes embarqués

International audienceLa conception d'un système embarqué implique une phase préalable de modélisation grâce à des outils (langages ou plate-formes) de modélisation. Chacun de ces outils utilise une approche de modélisation appropriée ; ce qui induit une dépendance forte entre la méthodologie et l'outil de modélisation. Il s'ensuit que le choix de la méthodologie par le concepteur est dicté par celui de l'outil à utiliser. Ce choix dépend à la fois des contraintes spécifiques du système et du niveau d'abstraction auquel il sera modélisé. Il est déterminant au niveau de la mise en œuvre du système car, il oriente la modélisation et contraint donc la conception. Ainsi, un mauvais choix peut compromettre la qualité et le coût de la conception. Cet article présente la méthodologie de modélisation basée sur des composants appelés « acteurs ». Sa valeur distinctive est présentée sur le plan de la structuration du système, de la séparation des préoccupations, et de la décomposabilité et recomposabilité modulaire

Execution Model for Non-Hierarchical Heterogeneous Modeling

International audienceTo combine different technology domains, modeling languages and platforms generally use a hierarchical approach. This approach avoids the combinatorial explosion of the number of interfaces between models of computation (MoC), but it for bids the use of components which have inputs or outputs that obey different MoCs. This affects the modularity and the reuse of the components. Moreover, the communication between two MoCs is implicitly defined in the modelling tool, and the designer doesnot have control over the semantics of what happens at the border between MoCs. In[7], we introduced a new approach that allows non-hierarchical heterogeneity based on heterogenous-interface components (HIC). In this paper, we present thearchitecture and the execution model we have designed to support HICs in PtolemyII

An Overall Specification of a Meta-Model of Computation For Model- Driven Embedded Systems

International audienceThe prototyping of embedded systems being long and expensive, software models are often defined to be used as a behavioral reference for better exploration and evaluation of the systems properties. However, embedded systems being naturally heterogeneous, they require the coexistence of several models of computation. In software engineering, the great challenge is how to specify heterogeneous interfaces for ensuring well defined communications because various semantic properties are mixed. Therefore, some existing approaches use only a set of few models of computation to reduce this complexity. Some others can use an open set of models of computation but reduce the complexity by forbidding to use different models of computation in the same hierarchical level. This paper proposes a modeling approach based on the meta-modeling of models of computation. It allows to mix different models of computation by using a meta-model of computation which provides a common semantic description at a higher abstraction level. This makes easier to specify the interactions between models of computation