Translation Of AADL To PNML To Ensure The Utilization Of Petri Nets

Architecture Analysis and Design Language (AADL), which is used to design and analyze software and hardware architectures of embedded and real-time systems, has proven to be a very efficient way of expressing the non-functional properties of safety-critical systems and architectural modeling. Petri nets are the graphical and mathematical modeling tools used to describe and study information processing systems characterized as concurrent and distributed. As AADL lacks the formal semantics needed to show the functional properties of such systems, the objective of this research was to extend AADL to enable other Petri nets to be incorporated into Petri Net Markup Language (PNML), an interchange language for Petri nets. PNML makes it possible to incorporate different types of analysis using different types of Petri net. To this end, the interchange format Extensible Markup Language (XML) was selected and AADL converted to AADL-XML (the XML format of AADL) and Petri nets to PNML, the XML-format of Petri nets, via XSLT script. PNML was chosen as the transfer format for Petri nets due to its universality, which enables designers to easily map PNML to many different types of Petri nets. Manual conversion of AADL to PNML is error-prone and tedious and thus requires automation, so XSLT script was utilized for the conversion of the two languages in their XML format. Mapping rules were defined for the conversion from AADL to PNML and the translation to XSLT automated. Finally, a PNML plug-in was designed and incorporated into the Open Source AADL Tool Environment (OSATE)

Rich Interfaces for Dependability: Compositional Methods for Dynamic Fault Trees and Arcade models

This paper discusses two behavioural interfaces for reliability analysis: dynamic fault trees, which model the system reliability in terms of the reliability of its components and Arcade, which models the system reliability at an architectural level. For both formalisms, the reliability is analyzed by transforming the DFT or Arcade model to a set of input-output Markov Chains. By using compositional aggregation techniques based on weak bisimilarity, significant reductions in the state space can be obtained

The safety case and the lessons learned for the reliability and maintainability case

This paper examine the safety case and the lessons learned for the reliability and maintainability case

A bibliography on formal methods for system specification, design and validation

Literature on the specification, design, verification, testing, and evaluation of avionics systems was surveyed, providing 655 citations. Journal papers, conference papers, and technical reports are included. Manual and computer-based methods were employed. Keywords used in the online search are listed

Performance evaluation of Fractal component based systems

International audienceComponent based system development is now a well accepted design approach in software engineering. Numerous component models have been proposed and for most of them, specific software tools allow building Component Based System (CBS). Although these tools perform several checks on the built system, few of them provide formal verification of behavioural properties nor performance evaluation of the resulting system. In this context, we have developed a general method associating to a CBS, a formal model, based on Stochastic Well formed Nets, a class of high level Petri Nets, allowing qualitative behavioural analysis together with performance evaluation of this CBS. The definition of the model heavily depends on the (run time) component model used to describe the CBS. In this paper, we instantiate our method to Fractal CBS and its reference Java implementation Julia. The method starts from the Fractal architectural description of a system, and defines rules to systematically generate elements models of the CBS and their interactions. We then apply a structured method both for qualitative and performance analysis taking into account the given implementation of the Fractal model. The main interest of our method is to take advantage of the compositional definition of such systems to carry out an efficient analysis. The paper concentrates on performance evaluation and presents our method step by step with an illustrative example

Analysis of emergency situations on the process of thermal power plants using mathematical apparatus of Petri nets

Article is dedicated to the issues of accident scenarios analysis on the process of thermal power plants. The theoretical foundations of the graphical and analytical representation of Petri nets are shown. The article describes the steam cycle process and listing of its technology protections. A state model for power unit equipment and technological protections under the influence of changes in critical process parameters (steam’s temperature, pressure, level) is presented. Conclusions about the plans for further work in this direction are proposed. 

Applications of Bayesian networks and Petri nets in safety, reliability, and risk assessments: A review

YesSystem safety, reliability and risk analysis are important tasks that are performed throughout the system lifecycle to ensure the dependability of safety-critical systems. Probabilistic risk assessment (PRA) approaches are comprehensive, structured and logical methods widely used for this purpose. PRA approaches include, but not limited to, Fault Tree Analysis (FTA), Failure Mode and Effects Analysis (FMEA), and Event Tree Analysis (ETA). Growing complexity of modern systems and their capability of behaving dynamically make it challenging for classical PRA techniques to analyse such systems accurately. For a comprehensive and accurate analysis of complex systems, different characteristics such as functional dependencies among components, temporal behaviour of systems, multiple failure modes/states for components/systems, and uncertainty in system behaviour and failure data are needed to be considered. Unfortunately, classical approaches are not capable of accounting for these aspects. Bayesian networks (BNs) have gained popularity in risk assessment applications due to their flexible structure and capability of incorporating most of the above mentioned aspects during analysis. Furthermore, BNs have the ability to perform diagnostic analysis. Petri Nets are another formal graphical and mathematical tool capable of modelling and analysing dynamic behaviour of systems. They are also increasingly used for system safety, reliability and risk evaluation. This paper presents a review of the applications of Bayesian networks and Petri nets in system safety, reliability and risk assessments. The review highlights the potential usefulness of the BN and PN based approaches over other classical approaches, and relative strengths and weaknesses in different practical application scenarios.This work was funded by the DEIS H2020 project (Grant Agreement 732242)