Fabrice Bernardi

Model design using hierarchical Web-based libraries

Design tools can be profitably associated with libraries of reusable modeling components that will make the description and also the validation of the models much easier. Furthermore, applications of today and tomorrow will be increasingly based on three fundamental technologies: Object Orientation, Client/Server and Internet. We propose in this article an object-oriented architecture for the definition of Web-based hierarchical models libraries. The originality of our approach lies in the facts that it is based on: (i) a notion of genericity of use, (ii) notions like inheritance and abstraction links between the stored models and (iii) Web-based storing and consulting libraries procedures.

BFS-DEVS: A General DEVS-Based Formalism For Behavioral Fault Simulation

Discrete event modeling allows designing an easy-to-handle and reusable representation of a system but, in its classical form, only permits one simulation at a time for a system. Concurrent and Comparative Simulation (CCS) with Multi-List Propagation (MLP) appears to be an adapted solution, by providing a way to perform several simulations in a single execution run. Concurrent Fault Simulation (CFS) has been one of the first applications of the CCS. The main obstacles to a wide use of this technique are the high complexity of the concurrent simulation algorithms, along with the difficulty to integrate them in a simulation kernel. We focus in this paper on the CFS with MLP of systems described in the new BFS-DEVS formalism, which is an evolution of the original DEVS Simulator that integrates the CCS algorithm. The appli- cation is performed in the behavioral digital domain of systems described in the VHDL language.

A generic framework for environmental modeling and simulation

Because of their complexity, natural systems are often studied using various modeling paradigms. This paper describes a generic framework for natural systems studies allowing the modeler to use all these paradigms in a unique environment. This framework is composed of a DEVS based modeling and simulation environment called JDEVS, and a models library called HMLib. The associated formal framework ensures that models are reusable and interoperable components with well-defined interfaces. Integration is performed using a Web based connector allowing a distributed work. The coupling between these two tools provides a powerful framework focusing on models interoperability and reusability.

Transformation of VHDL descriptions into DEVS models for fault modeling

We propose in this article an approach for the transformation of VHDL descriptions into DEVS models for an easy and fast fault simulation. VHDL allows description of the structure of a design, that is how it is decomposed into sub-designs, and how those designs are interconnected. The specification of the function of designs are performed using familiar programming language forms. One of the main problems is that today tools are unable to quickly and easily create and simulate fault models directly from the VHDL descriptions. A way to solve this problem is to encapsulate these descriptions in easily simulating and evolutive models. We propose to use the DEVS formalism to achieve this encapsulation.