Software dependability modeling using an industry-standard architecture description language

Performing dependability evaluation along with other analyses at architectural level allows both making architectural tradeoffs and predicting the effects of architectural decisions on the dependability of an application. This paper gives guidelines for building architectural dependability models for software systems using the AADL (Architecture Analysis and Design Language). It presents reusable modeling patterns for fault-tolerant applications and shows how the presented patterns can be used in the context of a subsystem of a real-life application

Mapping AADL to Petri Net Tool-Sets Using PNML Framework

Architecture Analysis and Design Language (AADL) has been utilized to specify and verify non- functional properties of Real-Time Embedded Systems (RTES) used in critical application systems. Examples of such critical application systems include medical devices, nuclear power plants, aer- ospace, financial, etc. Using AADL, an engineer is enable to analyze the quality of a system. For example, a developer can perform performance analysis such as end-to-end flow analysis to guarantee that system components have the required resources to meet the timing requirements relevant to their communications. The critical issue related to developing and deploying safety critical systems is how to validate the expected level of quality (e.g., safety, performance, security) and functionalities (capabilities) at design level. Currently, the core AADL is extensively applied to analyze and verify quality of RTES embed in the safety critical applications. The notation lacks the formal semantics needed to reason about the logical properties (e.g., deadlock, livelock, etc.) and capabilities of safety critical systems. The objective of this research is to augment AADL with exit- ing formal semantics and supporting tools in a manner that these properties can be automatically verified. Toward this goal, we exploit Petri Net Markup Language (PNML), which is a standard act- ing as the intermediate language between different classes of Petri Nets. Using PNML, we interface AADL with different classes of Petri nets, which support different types of tools and reasoning. The justification for using PNML is that the framework provides a context in which interoperability and exchangeability among different models of a system specified by different types of Petri nets is possible. The contributions of our work include a set of mappings and mapping rules between AADL and PNML. To show the feasibility of our approach, a fragment of RT-Embedded system, namely, Cruise Control System has been used

Scheduling Multi Clock Real Time Systems: From Requirements to Implementation

NewPort BeachInternational audienceThis paper presents an approach for modeling simulating and analyzing multi clocks real time systems during the different steps of a design. These steps range from the first requirements to a model allocated on a specific execution platform. The \uml \marte profile and the \ccsl language are used together to specify the causal and temporal characteristics of the software as well as the hardware parts of the system. The \tsq environment allows a simulation of such specification and the detection of potential errors and deadlocks. When the specification refinement is finished, to prove the specification correctness, the \ccsl specification is used to generate a synchronous model and some observers in Esterel. We illustrate the approach through a spark ignition control system

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)

Dependability modeling and evaluation – From AADL to stochastic Petri nets

Conduire des analyses de sûreté de fonctionnement conjointement avec d'autres analyses au niveau architectural permet à la fois de prédire les effets des décisions architecturales sur la sûreté de fonctionnement du système et de faire des compromis. Par conséquent, les industriels et les universitaires se concentrent sur la définition d'approches d'ingénierie guidées par des modèles (MDE) et sur l'intégration de diverses analyses dans le processus de développement. AADL (Architecture Analysis and Design Language) a prouvé son aptitude pour la modélisation d'architectures et ce langage est actuellement jugé efficace par les industriels dans de telles approches. Notre contribution est un cadre de modélisation permettant la génération de modèles analytiques de sûreté de fonctionnement à partir de modèles AADL dans l‘objectif de faciliter l'évaluation de mesures de sûreté de fonctionnement comme la fiabilité et la disponibilité. Nous proposons une approche itérative de modélisation. Dans ce contexte, nous fournissons un ensemble de sous-modèles génériques réutilisables pour des architectures tolérantes aux fautes. Le modèle AADL de sûreté de fonctionnement est transformé en un RdPSG (Réseau de Petri Stochastique Généralisé) en appliquant des règles de transformation de modèle. Nous avons implémenté un outil de transformation automatique. Le RdPSG résultant peut être traité par des outils existants pour obtenir des mesures de sûreté de fonctionnement. L'approche est illustrée sur un ensemble du Système Informatique Français de Contrôle de Trafic Aérien. ABSTRACT : Performing dependability evaluation along with other analyses at architectural level allows both predicting the effects of architectural decisions on the dependability of a system and making tradeoffs. Thus, both industry and academia focus on defining model driven engineering (MDE) approaches and on integrating several analyses in the development process. AADL (Architecture Analysis and Design Language) has proved to be efficient for architectural modeling and is considered by industry in the context presented above. Our contribution is a modeling framework allowing the generation of dependability-oriented analytical models from AADL models, to facilitate the evaluation of dependability measures, such as reliability or availability. We propose an iterative approach for system dependability modeling using AADL. In this context, we also provide a set of reusable modeling patterns for fault tolerant architectures. The AADL dependability model is transformed into a GSPN (Generalized Stochastic Petri Net) by applying model transformation rules. We have implemented an automatic model transformation tool. The resulting GSPN can be processed by existing tools to obtain dependability measures. The modeling approach is illustrated on a subsystem of the French Air trafic Control System