Formal Scenario Definition Language for Aviation: Aircraft Landing Case Study

Although the importance of scenarios in modeling and simulation has long been well known, there still exists a lack of common understanding and standardized practices in simulation scenario development. This paper proposes a Domain-Specific Language (DLS) to provide a standard scenario specification that will lead to a common mechanism for verifying and executing aviation scenarios, effective sharing of scenarios among various simulation environments, improve the consistency among different simulators and simulations, and even enable the reuse of scenario specifications. Following DSL design practices, the proposed Aviation Scenario Definition Language (ASDL) will provide a well-structured definition language to formally specify complete aircraft landing scenarios. In order to capture the necessary constructs for a simulation scenario, Simulation Interoperability Standards Organization (SISO) Base Object Model (BOM) is adopted as the baseline metamodel. This baseline is extended using the fundamentals of aircraft landing that cover all the domain-related concepts and terminology as constructs. By taking a formal approach in defining aviation scenarios, ASDL aims at providing consistency and completeness checking, and model-to-text transformations capabilities for various targets in the aviation scenario definition domain. The results of this work will be used to develop a graphical modeling environment and automatic means to transform scenario models into executable scenario scripts. The work presented here is the first stepping stone in formal scenario definition in aviation domain

Flight Simulator Model Integration for Supporting Pilot-in-the-Loop Testing in Model-Based Rotorcraft Design

Model-Based Design (MBD) enables iterative design practices and boosts the agility of the air vehicle development programs. Flight simulators are extensively employed in these programs for evaluating the handling qualities of the designed platforms. In order to keep up with the agility provided by the MBD, integration of the air vehicle models in fairly complex flight simulators needs to be addressed. The AVES Software Development Kit (SDK), which is the simulation software suite of DLR Air Vehicle Simulator (AVES), enables tackling the model integration starting from the modeler’s desktop. Additionally, 2Simulate, which is the enabling real-time simulation infrastructure of AVES SDK, provides automated model integration workflow for MATLAB/Simulink models using Simulink Coder code generation facilities. This paper presents the successful employment of AVES SDK and the 2Simulate model integration workflow for addressing integration challenges for Pilot-in-the-Loop Testing in AVES

Towards Enabling Level 3A AI in Avionic Platforms

The role of AI evolves from human assistance over human/machine collaboration towards fully autonomous systems. As the push towards more autonomy subsequently removes the reliance on a human overseeing the system, means of self supervision must be provided to enable safe operations. This work explores dynamic reconfiguration to provide resilience to unforeseen environmental conditions that exceed the systems capabilities, but also against normal faults. We focus on providing the means for this in an ARINC 653 compliant environment, since we target avionics platforms. Scheduling and communication are two major aspects of dynamic reconfiguration. Hence, we discuss multiple respective implementation approaches. The third pillar of reconfiguration, the process of deciding when to reconfigure is also investigated. Combining these yields the building blocks for a self-supervising system

Model-based Development of Enhanced Ground Proximity Warning System for Heterogeneous Multi-Core Architectures

The aerospace domain, very much similar to other cyber-physical systems domains such as automotive or automation, is demanding new methodologies and approaches for increasing performance and reducing cost, while maintaining safety levels and programmability. While the heterogeneous multi-core architectures seem promising, apart from certification issues, there is a solid necessity for complex toolchains and programming processes for exploiting their full potential. The ARGO (WCET-Aware PaRallelization of Model-Based Ap-plications for HeteroGeneOus Parallel Systems) project is addressing this challenge by providing an inte-grated toolchain that realizes an innovative holistic approach for programming heterogeneous multi-core sys-tems in a model-based workflow. Model-based design elevates systems modeling and promotes simulation with the executing these models for verification and validation of the design decisions. As a case study, the ARGO toolchain and workflow will be applied to a model-based Enhanced Ground Proximity Warning System (EGPWS) development. EGPWS is a readily available system in current aircraft which provides alerts and warnings for obstacles and terrain along the flight path utilizing high resolution terrain databases, Global Positioning System and other sensors-. After a gentle introduction to the model-based development approach of the ARGO project for the heterogeneous multi-core architectures, the EGPWS and the EGPWS systems modelling will be presented

Automatic Deployment of Embedded Real-time Software Systems to Hypervisor-managed Platforms

The deterministic integration of concurrent func- tions on shared multicore platforms is a challenging yet important task. Especially in safety-critical environments, hypervisors can be used to achieve time and space partitioning, but their sole application is often insufficient to guarantee deterministic timing and data flow behavior. Considering the growing complexity of modern embedded systems, for example in terms of functionality and mixed-criticality requirements, model-based approaches are a promising starting point to tackle this issue. In this work, we bridge the gap between a model-based behavior specification methodology based on the Logical Execution Time (LET) concept and target platforms running a commercially available bare- metal hypervisor. Therefore, this paper describes a runtime environment that implements LET semantics at the level of hypervisor partitions and a tool-supported design methodology that deploys software to this runtime environment. From a be- havior specification provided as a system model with annotated C code, the presented deployment tool generates binary images with guaranteed timing and data-flow behavior for the XtratuM hypervisor. The approach is finally validated by applying it to a Flight Assistance System (FAS) from the avionics domain

Interactive Parallelization of Embedded Real-Time Applications Starting from Open-Source Scilab & Xcos

International audienceIn this paper, we introduce the workflow of interactive parallelization for optimizing embedded real-time applications for multicore architectures. In our approach, the real-time applications are written in the Scilab high-level mathematical & scientific programming language or with a Scilab Xcos block-diagram ap-proach. By using code generation and code parallelization technol-ogy combined with an interactive GUI, the end user can map appli-cations to the multicore processor iteratively. The approach is eval-uated on two use cases: (1) an image processing application written in Scilab and (2) an avionic system modeled in Xcos. Using the workflow, an end-to-end model-based approach targeting multicore processors is enabled resulting in a significant reduction in devel-opment effort and high application speedup. The workflow de-scribed in this paper is developed and tested within the EU-funded ARGO project focused on WCET-Aware Parallelization of Model-Based Applications for Heterogeneous Parallel Systems

Cybersecurity Engineering: Bridging the Security Gaps in Avionics Architectures and DO-326A/ED-202A

Urban Air Mobility is envisioned as an on-demand, highly automated and autonomous air transportation modality. It requires the use of advanced sensing and data communication technologies to gather, process, and share flight-critical data. Where this sharing of mix-critical data brings opportunities, if compromised, presents serious cybersecurity threats and safety risks due to the cyber-physical nature of the airborne vehicles. Therefore the avionics system design approach of adhering to functional safety standards (DO-178C) alone is inadequate to protect the mission-critical avionics functions from cyber-attacks. To approach this challenge, the DO-326A/ED-202A standard provides a baseline to effectively manage cybersecurity risks and to ensure the airworthiness of airborne systems. In this regard, this paper pursues a holistic cybersecurity engineering and bridges the security gap by mapping the DO-326A/ED-202A system security risk assessment activities to the Threat Analysis and Risk Assessment process. It introduces Resilient Avionics Architecture as an experimental use case for Urban Air Mobility by apprehending the DO-326A/ED-202A standard guidelines. It also presents a comprehensive system security risk assessment of the use case and derives appropriate risk mitigation strategies. The presented work facilitates avionics system designers to identify, assess, protect, and manage the cybersecurity risks across the avionics system life cycle

Pragmatic model transformations for refactoring in Scilab/Xcos

Model-Based Development has become an industry wide standard paradigm. As an open source alternative, Scilab/Xcos is being widely employed as a hybrid dynamic systems modeling tool. With the increasing efficiency in implementation using graphical model development and code generation, the modeling and simulation community is struggling with assuring quality as well as maintainability and extendibility. Refactoring is defined as an evolutionary modernization activity where, most of the time, the structure of the artifact is changed to alter its quality characteristics, while keeping its behaviour unchanged. It has been widely established as a technique for textual programming languages to improve the code structure and quality. While refactoring is also regarded as one of the key practices of model engineering, the methodologies and approaches for model refactoring are still under development. Architecture-Driven Modernization (ADM) has been introduced by the software engineering community as a model-based approach to software modernization, in which the implicit information that lies in software artifacts is extracted to models and model transformations are applied for modernization tasks. Regarding refactoring as a low level modernization task, the practices from ADM are adaptable. Accordingly, this paper proposes a model-based approach for model refactoring in order to come up with more efficient and effective model refactoring methodology that is accessible and extendable by modelers. Like other graphical modeling tools, Scilab/Xcos also possesses a formalized model specification conforming to its implicit metamodel. Rather than proposing another metamodel for knowledge extraction, this pragmatic approach proposes to conduct in place model-to-model transformations for refactoring employing the Scilab/Xcos model specification. To construct a structured model-based approach, the implicit Scilab/Xcos metamodel is explicitly presented utilizing ECORE as a meta-metamodel. Then a practical model transformation approach is established based on Scilab scripting. A Scilab toolset is provided to the modeler for in-place model-to-model transformations. Using a sample case study, it is demonstrated that proposed model transformation functions in Scilab provide a valuable refactoring tool

Yörünge benzetimi için ontoloji temelli yeniden kullanım altyapısı.

In this research, we developed an ontology based reuse infrastructure for trajectory simulation and investigated the use of ontologies and domain engineering practices to develop a formalized methodology to make use of the experience and knowledge leveraged from the past trajectory simulation projects. Trajectory simulation in this context is a computational tool to calculate the flight path and other parameters of munition such as its orientation or angular rates during its operation In this thesis, engineering knowledge to simulate the trajectory of a munition is captured in an ontology called Trajectory Simulation ONTology (TSONT). Concepts of trajectory simulation and the relation among these concepts are captured by using Web Ontology Language and presented as a domain model that is available for reuse. Using the formalized domain knowledge, reuse infrastructure specifications are constructed to enable the reuse of software artifacts for two main programming paradigms, which are object oriented programming and function oriented programming. UML and application frameworks are used when constructing for object oriented paradigm. And data flow diagrams are used to formalize the design of the function oriented simulations to compute the trajectory of munition. Object oriented and function oriented platform independent designs are constructed to specify the infrastructure using the knowledge captured in TSONT and made available for reuse. With constructing two different designs for two different paradigms by using the same domain model, evidence of knowledge reuse were produced. Three different case studies were carried out as infrastructure implementation. In the first case study, an object oriented application framework was developed in MATLAB for six degrees of freedom trajectory simulation using platform independent object oriented design. This framework is reused to develop two different simulations. Using the developed framework for two applications produced evidence of code reuse. In the second case, a point mass trajectory simulation framework is designed to be implemented in C# reusing the same platform independent object oriented design. This case produced the evidence of design reuse. In the last case study, a MATLAB Simulink Blockset is developed for point mass unguided trajectory simulations and two different simulations are built using the Blockset. By this case, we collected the evidence of code reuse also in function oriented paradigm.Ph.D. - Doctoral Progra