Walid Karamti

Using MDE and priority time petri nets for the schedulability analysis of embedded systems modeled by UML activity diagrams

This paper proposes a model driven approach for the schedulability analysis at an early stage of the embedded system development life-cycle. The activity diagram of Unified Modeling Language (UML) annotated with the profile for the Modeling and Analysis of Real-Time and Embedded systems (MARTE) is mapped into Priority Time Petri Net (PTPN) to enhance formal schedulability test of given real time tasks. The generated PTPN model is interpreted and executed to check whether a schedule of a task execution meets the imposed timing constraints. Therefore, the present paper focuses on the definition of temporal properties and tasks dependency by means of activity diagram and MARTE profile. Besides, it describes the transformation rules from analysis model to formal model.

Compositional specification of real time embedded systems by priority time Petri Nets

An important key challenge in Embedded Real Time Systems (ERTS) analysis is to provide a seamless scheduling strategy. Formal methods for checking the temporal characteristics and timing constraints at a high abstraction level have proven to be useful for making the development process reliable. In this paper, we present a Petri Net modeling formalism and an analysis technique which supports not only systems scheduling analysis but also the compositional specification of real time systems. The proposed Priority Time Petri Net gives determinism aspect to the model and accelerates its execution. Indeed, a compositional specification of a PTPN for complex application and multiprocessor architecture that solves the problem of hierarchy is presented.

Scheduling analysis based on model checking for multiprocessor real-time systems

Real-time systems (RTS) are omnipresent in several domains. The trend is to use multiprocessor architecture to satisfy the timing constraints of such systems. The model-checking methods have proven to be useful for making the development process reliable at a high abstraction level. Based on this approach, the present paper proposes a new technique for scheduling analysis of a partitioned multiprocessor RTS. Starting from a model with dynamic priority time Petri Nets modeling the system, we have proposed a generation of a reduced states graph. Thus, through the properties of the graph the schedulability is checked. Our approach provides an implementation of a Partition Checker tool, which produces an affirmation of the schedulability or a counterexample in the case of non-schedulable system to reduce the SW/HW space exploration.

Transformation process of RTS scheduling analysis requirements from UML/MARTE to dynamic priority time Petri Nets

The real-time system (RTS) design is a major challenge due to the complexity of the considered application and the appearance of multiprocessor architectures. Most of the research in this area is interested in high abstraction level methods to decrease the design convolution. In particular, the Unified Modeling Language (UML) profiles and the Model Driven Engineering (MDE) aim at being an adequate solution to support the whole life cycle of RTS design with its real-time constraints and performance issues. Based on MDE and the Modeling and Analysis of Real-Time and Embedded systems (MARTE) profile, the present manuscript proposes an interactive partitioning scheduling of RTS running on multiprocessor architecture. A special attention is paid to the scheduling analysis step to accelerate the exploration of HW/SW space solution. Starting from a candidate solution modeled with UML activity and annotated with MARTE stereotypes, a mapping process to dynamic priority time Petri Nets (dPTPN) was defined. The considered dPTPN is able to prove the schedulability or provide a counterexample to determine the partitions causes of temporal fault. This counterexample presents a useful feedback to the HW/SW space solution explorer in the aim to exclude all solution containing the described partitions.

States Graph Generation from dynamic Priority Time Petri Nets

dynamic Priority Time Petri Nets (dPTPN) is a mathematical formalism dedicated to modeling Real-Time System (RTS) and checking its schedulability. The present paper proposes a states graph generation from a reduced dPTPN model in order to deal with the scheduling analysis. Based on hierarchical modeling, the present model presents only the interaction between all RTS components and excluding their internal behavior. According to this reduction, a new denition of state is given. Hence, all reachable states and edges connecting between them are generated to show a prediction of the RTS scheduling. Thus, the resulting graph gives birth to an open research area in the purpose of checking its properties and deducing the schedulability.

A model driven engineering based method for scheduling analysis

MDE can be used to model and analyze ERTS. However, scheduling problems are not totally covered using this approach. Traditionally, the design of these systems is limited to the characterization of the architecture and the application. Since MDE neglects task scheduling, designers are obliged to use simulation methods. This paper presents a scheduling analysis method for real time systems at an early stage. The proposed approach adopts the MDE concept based UML models and rule transformation in order to find a feasible schedule that satisfies timing constraints.