A formal approach using SysML for capturing functional requirements in avionics domain

In this work,a Model-Based Systems Engineering approach based on Sys ML is proposed.This approach is used for the capture and the definition of functional requirements in avionics domain.The motivation of this work is triple:guide the capture of functional requirements,validate these functional requirements through functional simulation,and verify efficiently the consistency of these functional requirements.The proposed approach is decomposed into several steps that are detailed to go from conceptual model of avionics domain to a formal functional model that can be simulated in its operating context.To achieve this work,a subset of Sys ML has been used as an intermediate modelling language to ensure progressive transformation that can be understood and agreed by system stakeholders.Formal concepts are introduced to ensure theoretical consistency of the approach.In addition,transformation rules are defined and the mappings between concepts of ARP4754 A civil aircraft guidelines and Sys ML are formalized through meta-model.The resulting formalization enables engineers to perform functional simulation of the top-level functional architecture extracted from operational scenarios.Finally,the approach has been tested on an industrial avionics system called the Onboard Maintenance System.

Efficient schedulability analysis for mixed-criticality systems under deadline-based scheduling

Safety-critical avionics systems which become more complex and tend to integrate multiple functionalities with different levels of criticality for better cost and power efficiency are subject to certifications at various levels of rigorousness. In order to simultaneously guarantee temporal constraints at all different levels of assurance mandated by different criticalities, novel scheduling techniques are in need. In this paper, a mixed-criticality sporadic task model with multiple virtual deadlines is built and a certification-cognizant dynamic scheduling approach referred as earliest virtual-deadline first with mixed-criticality（EVDF-MC） is considered, which exploits different relative deadlines of tasks in different criticality modes. As for the corresponding schedulability analysis problem, a sufficient and efficient schedulability test is proposed on the basis of demand-bound functions derived in the mixed-criticality scenario. In addition, a modified simulated annealing（MSA）-based heuristic approach is established for virtual deadlines assignment. Experiments performing simulations with randomly generated tasks indicate that the proposed approach is computationally efficient and competes well against the existing approaches.

An overview on development of miniature unmanned rotorcraft systems

In this article,we attempt to document a technical overview on modern miniature unmanned rotorcraft systems.We first give a brief review on the historical development of the rotorcraft unmanned aerial vehicles(UAVs),and then move on to present a fairly detailed and general overview on the hardware configuration,software integration,aerodynamic modeling and automatic flight control system involved in constructing the unmanned system.The applications of the emerging technology in the military and civilian domains are also highlighted.