liu.seSearch for publications in DiVA
Change search
Link to record
Permanent link

Direct link
Saar de Moraes, Rodrigo
Publications (4 of 4) Show all publications
Saar de Moraes, R. (2024). Exploring Trade-offs in Concept Design of Integrated Modular Avionic Platform Configurations: Topology Generation, Resource Adequacy, and Dependability. (Doctoral dissertation). Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Exploring Trade-offs in Concept Design of Integrated Modular Avionic Platform Configurations: Topology Generation, Resource Adequacy, and Dependability
2024 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Modern aircraft heavily depend on computer systems to carry out various tasks. From managing flight surfaces and engines to processing radar and imagery data and facilitating communication with other aircraft and ground stations, computers are involved in almost every aspect of an aircraft’s operation. These computer systems, known as Integrated Modular Avionics (IMA) systems, have long life cycles that span several decades and undergo regular updates. Despite this, a significant portion of the overall life cycle costs is determined very early in the life cycle, in the concept design phase. 

While the early concept stage provides the best opportunity to influence the design of the system and its future costs, it is also the stage where information about the system is most limited. During this early stage, selecting a suitable IMA platform configuration must ensure sufficient resources for the intended aircraft functionalities, particularly in computing and networking capabilities. Additionally, the decisions regarding safety and security measures must align with application requirements. However, this is a complex task due to conflicting requirements, necessitating compromises, and the limited information available at this early stage. 

This thesis explores the analysis and generation of avionic architecture configurations during the concept stage, addressing the problem on two fronts. The first focuses on verifying whether a chosen IMA platform configuration provides sufficient resources to ensure timely communication for a specified set of avionic applications. The second centers on exploring the conceptual design space to find IMA platform configurations aligned with computing, networking, fault-tolerance, and security application needs. 

To contribute to the problem’s verification aspect, this thesis introduces two high-level abstractions, namely timed automata and a domain-specific model based on Unified Modelling Languages (UML), to model IMA systems at the concept stage. These are designed to capture inter-process message ex-changes within networked IMA platforms. Additionally, we propose a workflow and a supporting tool explicitly designed to translate our proposed model into a network calculus model for further analysis. The approach’s practicality and scalability are showcased through its application to an avionics use case. 

In exploring conceptual design space, this thesis proposes NetGAP, a domain-specific method in which interconnection patterns in generic networked system topologies are represented as graph grammars. Combined with Monte Carlo Tree Search and genetic algorithms, these grammars are used to navigate the solution space and generate candidate IMA platform configurations tailored to the requirements of an envisaged application. Through application to an avionics use case, NetGAP is shown to be scalable and suitable for different types of requirements. To further expedite the process, NetGAP has evolved into NeuralGAP. The latter employs graph neural networks to assess network topology compatibility with the target application, accelerating the concept exploration and improving its results.  

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2024. p. 67
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 2384
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-203166 (URN)10.3384/9789180756143 (DOI)9789180756136 (ISBN)9789180756143 (ISBN)
Public defence
2024-06-05, Key 1, Key-building, Campus Valla, Linköping, 13:00 (English)
Opponent
Supervisors
Funder
Vinnova, NFFP7 2017-04890; 2023-01183
Available from: 2024-04-30 Created: 2024-04-30 Last updated: 2024-05-24Bibliographically approved
Saar de Moraes, R. & Nadjm-Tehrani, S. (2022). Concept Level Explorationof IMA-based Networked Platforms with Mixed Time-Sensitive Communication Requirements. In: 33rd Congress of the International Council of the Aeronautical Sciences, Stockholm, Sweden, 2022: . Paper presented at ICAS2022, Stockholm, Sweden, 4-9 September, 2022.
Open this publication in new window or tab >>Concept Level Explorationof IMA-based Networked Platforms with Mixed Time-Sensitive Communication Requirements
2022 (English)In: 33rd Congress of the International Council of the Aeronautical Sciences, Stockholm, Sweden, 2022, 2022Conference paper, Published paper (Refereed)
Abstract [en]

In this paper, we apply a grammar-based approach to generate computation and communication platforms for avionic applications with mixed classes of time-sensitive communication messages. Then, we propose an evolutionary algorithm to schedule communication in the platform considering the interaction between timetriggered and bandwidth-constrained traffic. Together, the platform generation approach and the scheduling algorithm support the exploration of avionic systems at the concept level.

Keywords
platform architecture exploration; time-sensitive networks; mixed-critical communication; communication scheduling; timeliness analysis
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-203165 (URN)
Conference
ICAS2022, Stockholm, Sweden, 4-9 September, 2022
Available from: 2024-04-30 Created: 2024-04-30 Last updated: 2024-04-30Bibliographically approved
Saar de Moraes, R., Bernardi, S. & Nadjm-Tehrani, S. (2021). A model-based approach for analysing network communication timeliness in IMA systems at concept level. In: Proceedings of the 29th International Conference on Real-Time Networks and Systems: . Paper presented at RTNS'2021: 29th International Conference on Real-Time Networks and Systems NANTES France April 7 - 9, 2021 (pp. 78-88). Association for Computing Machinery
Open this publication in new window or tab >>A model-based approach for analysing network communication timeliness in IMA systems at concept level
2021 (English)In: Proceedings of the 29th International Conference on Real-Time Networks and Systems, Association for Computing Machinery , 2021, p. 78-88Conference paper, Published paper (Refereed)
Abstract [en]

Analyzing the resource adequacy of complex cyber-physical systems at concept development stage can be a challenging task since there are a lot of uncertainties about the system at this stage. In Integrated Modular Avionics (IMA) systems, with a life-cycle over several decades and potential functionality changes, we need to estimate resource needs at the early stage but leave capacity to absorb future modifications. Given an envisaged set of functions and a mapping to a candidate platform, one needs to assure that the selected network configuration will provide adequate resources to meet communication timeliness. In particular, whether the set of switches, the topology, and the available bandwidth are sufficient to meet the envisaged needs. In this paper, timeliness requirements are expressed as constraints on the freshness of data and a strict bounding of end-to-end latency. We support generation of UML/MARTE-based specifications by creating a domain-specific meta-model for IMA systems and a resource modelling approach for the study of time-critical systems. The instances of this model then specify the application requirements and various network configurations that can be formally analyzed. We present a tool, M2NC, for automatic derivation of a network calculus model through model transformation, and use the state-of-art NC tools for deriving the bounds for end-to-end timeliness. The approach is illustrated on an example avionics case study, consisting of 91 computational processes that exchange 629 different types of messages. The results of the analysis show that our approach can efficiently provide feedback on configurations that are compliant with the requirements imposed by the application and the toolchain provides a systematic mechanism to quickly identify potential future bottlenecks.

Place, publisher, year, edition, pages
Association for Computing Machinery, 2021
Series
RTNS ’21
Keywords
UML-MARTE, Real-Time Systems, Network Resource Adequacy, Model Verification, Concept Analysis
National Category
Computer Systems
Identifiers
urn:nbn:se:liu:diva-203160 (URN)10.1145/3453417.3453427 (DOI)
Conference
RTNS'2021: 29th International Conference on Real-Time Networks and Systems NANTES France April 7 - 9, 2021
Note

Funding: This work was supported by the Swedish Governmental Agency for Innovation Systems- Vinnova, as part of the national projects on aeronautics, NFFP7, project CLASSICS (NFFP7 2017-04890). Simona Bernardi was partially supported by the project Medrese (RTI2018098543-B-I00) by the Spanish Ministry of Science, Innovation and Universities.

Available from: 2024-04-30 Created: 2024-04-30 Last updated: 2024-04-30
Saar de Moraes, R. & Nadjm-Tehrani, S. (2020). Verifying Resource Adequacy of Networked IMA Systems at Concept Level. In: Hasan, O. and Mallet, F. (Ed.), Formal Techniques for Safety-Critical Systems: . Paper presented at Formal Techniques for Safety-Critical Systems (FTSCS), Shenzhen, China, November 9, 2019 (pp. 40-56). Cham: Springer
Open this publication in new window or tab >>Verifying Resource Adequacy of Networked IMA Systems at Concept Level
2020 (English)In: Formal Techniques for Safety-Critical Systems / [ed] Hasan, O. and Mallet, F., Cham: Springer, 2020, p. 40-56Conference paper, Published paper (Refereed)
Abstract [en]

Complex cyber-physical systems can be difficult to analyze for resource adequacy at the concept development stage since relevant models are hard to create. During this period, details about the functions to be executed or the platforms in the architecture are partially unknown. This is especially true for Integrated Modular Avionics (IMA) Systems, for which life-cycles span over several decades, with potential changes to functionality in the future. To support the engineers evaluating conceptual designs there is a need for tools that model resources of interest in an abstract manner and allow analyses of changing architectures in a modular and scalable way. This work presents a generic timed automata-based model of a networked IMA system abstracting complex networking and computational elements of an architecture, but representing the communication needs of each application function using UPPAAL templates. The proposed model is flexible and can be modified/extended to represent different types of network topologies and communication patterns. More specifically, the different components of the IMA network, Core Processing Modules, Network End-Systems, and Switches, are represented by different templates. The templates are then instantiated to represent a conceptual design, and fed into a model checker to verify that a given platform instance supports the desired system functions in terms of network bandwidth and buffer size adequacy - in particular, whether messages can reach their final destination on time. The work identifies the limits of the tool used for this evaluation, but the conceptual model can be carried over to other tools for further studies.

Place, publisher, year, edition, pages
Cham: Springer, 2020
Series
Communications in Computer and Information Science, ISSN 1865-0929 ; 1165
Keywords
Timed automata, UPPAAL, IMA system, Concept analysis, Network resource adequacy
National Category
Computer Engineering
Identifiers
urn:nbn:se:liu:diva-170069 (URN)10.1007/978-3-030-46902-3_3 (DOI)978-3-030-46901-6 (ISBN)
Conference
Formal Techniques for Safety-Critical Systems (FTSCS), Shenzhen, China, November 9, 2019
Projects
NFFP7, project CLASSICS (NFFP7-04890)
Funder
Vinnova, NFFP7-04890
Available from: 2020-09-28 Created: 2020-09-28 Last updated: 2024-04-30Bibliographically approved
Organisations

Search in DiVA

Show all publications