The real-time scheduling theory provides analytical methods to assess the temporal predictability of embedded systems. Nevertheless, their use is limited in a Model-Based Systems Engineering approach. In fact, the large number of applicability conditions makes the use of real-time scheduling analysis tedious and error-prone. Key issues are left to the engineers: when to apply a real-time scheduling analysis? What to do with the analysis results? This article presents an approach to systematize and then automate the analysis of non-functional properties in Model-Based Systems Engineering. First, preconditions and postconditions define the applicability of an analysis. In addition, contracts specify the analysis interfaces, thereby enabling to reason about the analysis process. We present a proof-of-concept implementation of our approach using a combination of constraint languages (REAL for run-time analysis) and specification languages (Alloy for describing interfaces and reasoning about them). This approach is experimented on architectural models written with the Architecture Analysis and Design Language (AADL).

Model-Driven Engineering (MDE) is a relevant approach to support the engineering of distributed embedded systems with performance and dependability constraints. MDE involves models definitions and transformations to cover most of the system life-cycle: design, implementation and Verification & Validation activities towards system qualification. Still, few works evaluate the early integration of performance evaluation based on architectural models. In this paper, we investigate the early-stage use of analysis in AADL modeling. Precisely, we exemplify on an avionics case study how to dimension the data flows for an application distributed over an AFDX network. Based on the insight from this study, we suggest a simple framework and associated techniques to efficiently support analysis activities in the early-stage design phases.

Abstract-In the design of real-time systems, models are usual artifacts to capture and represent the various features of the system. They are later analyzed to check for their correctness. A key issue is to handle models and analyses in a systematic, consistent and efficient way. This paper presents an approach for the systematic and correct execution of analyses on real-time system models along with a proof-of-concept.The contribution aims at 1) directing the analyses targeting goals and 2) using contracts to reason about models, analyses and goals. An example of goal is to enrich a model with missing information or to obtain precise data to conclude about the system quality. In our approach, contracts are used to formally depict both the properties required and provided by the analyses ; but also models and goals. Through the concept of contracts, we identify all the feasible paths to execute the analyses in order to reach a goal.