An implementation of the behavior annex in the AADL-toolset Osate2

AADL is a modeling language to design and analyze High-Integrity Distributed and Real-time systems. Embedded sub-languages published as AADL annexes extend an AADL model to enhance analysis. The behavior annex specifies the behavior of an AADL application model. An implantation of this annex allows to perform behavior analysis. In addition, as there are several AADL annexes, the implementation of generic mechanisms to support each one of them is challenging. The behavior annex is a valid candidate to illustrate these challenges by combining several sub-languages. In this paper we expose our experiment to support the behavior annex in the reference AADL toolset OSATE2. This one, supports the AADL version 2 by providing a front-end and a set of analysis plug-ins to analyze an AADL model

An architecture-based dependability modeling framework using AADL

For efficiency reasons, the software system designers' will is to use an integrated set of methods and tools to describe specifications and designs, and also to perform analyses such as dependability, schedulability and performance. AADL (Architecture Analysis and Design Language) has proved to be efficient for software architecture modeling. In addition, AADL was designed to accommodate several types of analyses. This paper presents an iterative dependency-driven approach for dependability modeling using AADL. It is illustrated on a small example. This approach is part of a complete framework that allows the generation of dependability analysis and evaluation models from AADL models to support the analysis of software and system architectures, in critical application domains

AADLib, A Library of Reusable AADL Models

The SAE Architecture Analysis and Design Language is now a well-established language for the description of critical embedded systems, but also cyber-physical ones. A wide range of analysis tools is already available, either as part of the OSATE tool chain, or separate ones. A key missing elements of AADL is a set of reusable building blocks to help learning AADL concepts, but also experiment already existing tool chains on validated real-life examples. In this paper, we present AADLib, a library of reusable model elements. AADLib is build on two pillars: 1/ a set of ready-to- use examples so that practitioners can learn more about the AADL language itself, but also experiment with existing tools. Each example comes with a full description of available analysis and expected results. This helps reducing the learning curve of the language. 2/ a set of reusable model elements that cover typical building blocks of critical systems: processors, networks, devices with a high level of fidelity so that the cost to start a new project is reduced. AADLib is distributed under a Free/Open Source License to further disseminate the AADL language. As such, AADLib provides a convenient way to discover AADL concepts and tool chains, and learn about its features

The AADL Constraint Annex

The SAE Architecture Analysis and Design Language -- AADL has been defined with a strong focus on the careful modeling of critical real-time embedded systems. Around this formalism, several analysis tools have been defined, e.g. scheduling, safety, security or performance. The SAE AS2-C wishes to complement the AADL with a versatile language to support project-specific analysis. The Model Constraints Sublanguage Annex (or in short the Constraints Annex) provides a standard AADL sublanguage extension with three major objectives: •to allow specification of project specific AADL language subsets and enforce consistent use of the language subset over all classifiers in a package and all packages in a project •to allow specification of project specific Structural Assertions on AADL instance models of component implementations and specification of Structural Assertions on classifier types (component types, feature group types and their extensions) •to allow the specification of Behavior Assertions for feature groups, component types and component implementations, grouped as Assumptions and Guarantees. Assumptions group together Behavior Assertions describing expected behavior of the environment in which a component will operate. Guarantees group together Behavior Assertions which must be honored by all instances of the component, assuming that it is deployed into an environment that honors the Assumptions Behavior Assertions. In this presentation, we will provide an overview of this language, and report on ongoing implementation efforts to date for this language

Combining SysML and AADL for the design, validation and implementation of critical systems

The realization of critical systems goes through multiple phases of specification, design, integration, validation, and testing. It starts from high-level sketches down to the final product. Model-Based Design has been acknowledged as a good conveyor to capture these steps. Yet, there is no universal solution to represent all activities. Two candidates are the OMG-based SysML to perform high-level modeling tasks, and the SAE AADL to perform lower-level ones, down to the implementation. The paper shares an experience on the seamless use of SysML and the AADL to model, validate/verify and implement a flight management system

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

A Model-based transformation process to validate and implement high-integrity systems

Despite numerous advances, building High-Integrity Embedded systems remains a complex task. They come with strong requirements to ensure safety, schedulability or security properties; one needs to combine multiple analysis to validate each of them. Model-Based Engineering is an accepted solution to address such complexity: analytical models are derived from an abstraction of the system to be built. Yet, ensuring that all abstractions are semantically consistent, remains an issue, e.g. when performing model checking for assessing safety, and then for schedulability using timed automata, and then when generating code. Complexity stems from the high-level view of the model compared to the low-level mechanisms used. In this paper, we present our approach based on AADL and its behavioral annex to refine iteratively an architecture description. Both application and runtime components are transformed into basic AADL constructs which have a strict counterpart in classical programming languages or patterns for verification. We detail the benefits of this process to enhance analysis and code generation. This work has been integrated to the AADL-tool support OSATE2

A MDE-based process for the design, implementation and validation of safety critical systems

Distributed Real-Time Embedded (DRE) systems have critical requirements that need to be verified. They are either related to functional (e.g. stability of a furnace controller) or non-functional (e.g. meeting deadlines) aspects. Model-Driven Engineering (MDE) tools have emerged to ease DRE systems design. These tools are also capable of generating code. However, these tools either focus on the functional aspects or on the runtime architecture. Hence, the development cycle is partitioned into pieces with heterogeneous modeling notations and poor coordination. In this paper, we propose a MDE-based process to create DRE systems without manual coding. We show how to integrate functional and architecture concerns in a unified process. We use industry-proven modeling languages to design functional elements of the system, and automatically integrate them using our AADL toolchain

Expressing and enforcing user-defined constraints of AADL models

The Architecture Analysis and Design Language AADL allows one to model complete systems, but also to define specific extensions through property sets and library of models. Yet, it does not define an explicit mechanism to enforce some semantics or consistency checks to ensure property sets are correctly used. In this paper, we present REAL (Requirements and Enforcements Analysis Language) as an integrated solution to this issue. REAL is defined as an AADL annex language. It adds the possibility to express constraints as theorems based on set theory to enforce implicit semantics of property sets or AADL models. We illustrate the use of the language on case studies we developed with industrial partners