Model-Based System Engineering Methodology for Implementing Networked Aircraft Control System on Integrated Modular Avionics - Environmental Control System Case Study

Integrated Modular Avionics (IMA) architecture host multiple federated avionics applications into a single platform and provides benefits in terms of Size, Weight and Power (SWaP), nonetheless brings a high level of complexity to aircraft control systems. The thesis presents Model-Based System Engineering a novel, structured development methodology to cope efficiently with increased complexity due to IMA. Using ARCADIA methodology and the open source Capella tool, the developed methodology is implemented for a complete design cycle: starting with capturing requirements from the aircraft level to streamlining the development, integration of avionics application in an ARINC 653 platform. The proposed methodology provides effective traceability and management of specification artifacts from aircraft to system to item-level adhering to SAE ARP4754A guideline. Further, the thesis presents the capability of the MBSE framework to effectively address a few technological variants through the proposed methodology. To illustrate the efficiency of the methodology and MBSE approach an Environmental Control System (ECS) case study is presented. The case study focuses on implementing ECS in an IMA architecture using MBSE framework and proposed methodology. However, the derived methodology is also applicable to other systems. Further, the case study also presents a demonstration of integrating Cabin Pressure Control Sub-system (CPCS) into a real-time IMA platform for validation of MBSE approach. In addition, the thesis provides important insights in challenges and advantages of the MBSE process in contrast to the traditional paper-based specification process

Integration of generic operating systems in partitioned architectures

Tese de mestrado, Engenharia Informática (Arquitectura, Sistemas e Redes de Computadores), Universidade de Lisboa, Faculdade de Ciências, 2009The Integrated Modular Avionics (IMA) specification defines a partitioned environment hosting multiple avionics functions of different criticalities on a shared computing platform. ARINC 653, one of the specifications related to the IMA concept, defines a standard interface between the software applications and the underlying operating system. Both these specifications come from the world of civil aviation, but they are getting interest from space industry partners, who have identified common requirements to those of aeronautic applications. Within the scope of this interest, the AIR architecture was defined, under a contract from the European Space Agency (ESA). AIR provides temporal and spatial segregation, and foresees the use of different operating systems in each partition. Temporal segregation is achieved through the fixed cyclic scheduling of computing resources to partitions. The present work extends the foreseen partition operating system (POS) heterogeneity to generic non-real-time operating systems. This was motivated by documented difficulties in porting applications to RTOSs, and by the notion that proper integration of a non-real-time POS will not compromise the timeliness of critical real-time functions. For this purpose, Linux is used as a case study. An embedded variant of Linux is built and evaluated regarding its adequacy as a POS in the AIR architecture. To guarantee safe integration, a solution based on the Linux paravirtualization interface, paravirt-ops, is proposed. In the course of these activities, the AIR architecture definition was also subject to improvements. The most significant one, motivated by the intended increased POS heterogeneity, was the introduction of a new component, the AIR Partition OS Adaptation Layer (PAL). The AIR PAL provides greater POS-independence to the major components of the AIR architecture, easing their independent certification efforts. Other improvements provide enhanced timeliness mechanisms, such as mode-based schedules and process deadline violation monitoring.A especificação Integrated Modular Avionics (IMA) define um ambiente compartimentado com funções de aviónica de diferentes criticalidades a coexistir numa plataforma computacional. A especificação relacionada ARINC 653 define uma interface padrão entre as aplicações e o sistema operativo subjacente. Ambas as especificações provêm do mundo da aviónica, mas estão a ganhar o interesse de parceiros da indústria espacial, que identificaram requisitos em comum entre as aplicações aeronáuticas e espaciais. No âmbito deste interesse, foi definida a arquitectura AIR, sob contrato da Agência Espacial Europeia (ESA). Esta arquitectura fornece segregação temporale espacial, e prevê o uso de diferentes sistemas operativos em cada partição. A segregação temporal é obtida através do escalonamento fixo e cíclico dos recursos às partições. Este trabalho estende a heterogeneidade prevista entre os sistemas operativos das partições (POS). Tal foi motivado pelas dificuldades documentadas em portar aplicações para sistemas operativos de tempo-real, e pela noção de que a integração apropriada de um POS não-tempo-real não comprometerá a pontualidade das funções críticas de tempo-real. Para este efeito, o Linux foi utilizado como caso de estudo. Uma variante embedida de Linux é construída e avaliada quanto à sua adequação como POS na arquitectura AIR. Para garantir uma integração segura, é proposta uma solução baseada na interface de paravirtualização do Linux, paravirt-ops. No decurso destas actividades, foram também feitas melhorias à definição da arquitectura AIR. O mais significante, motivado pelo pretendido aumento da heterogeneidade entre POSs, foi a introdução de um novo componente, AIR Partition OS Adaptation Layer (PAL). Este componente proporciona aos principais componentes da arquitectura AIR maior independência face ao POS, facilitando os esforços para a sua certificação independente. Outros melhoramentos fornecem mecanismos avançados de pontualidade, como mode-based schedules e monitorização de incumprimento de metas temporais de processos.ESA/ITI - European Space Agency Innovation Triangular Initiative (through ESTEC Contract 21217/07/NL/CB-Project AIR-II) and FCT - Fundação para a Ciência e Tecnologia (through the Multiannual Funding Programme

C-EMO: A Modeling Framework for Collaborative Network Emotions

Recent research in the area of collaborative networks is focusing on the social and organizational complexity of collaboration environments as a way to prevent technological failures and consequently contribute for the collaborative network’s sustainability. One direction is moving towards the need to provide “human-tech” friendly systems with cognitive models of human factors such as stress, emotion, trust, leadership, expertise or decision-making ability. In this context, an emotion-based system is being proposed with this thesis in order to bring another approach to avoid collaboration network’s failures and help in the management of conflicts. This approach, which is expected to improve the performance of existing CNs, adopts some of the models developed in the human psychology, sociology and affective computing areas. The underlying idea is to “borrow” the concept of human-emotion and apply it into the context of CNs, giving the CN players the ability to “feel emotions”. Therefore, this thesis contributes with a modeling framework that conceptualizes the notion of “emotion” in CNs and a methodology approach based on system dynamics and agent-based techniques that estimates the CN player’s “emotional states” giving support to decision-making processes. Aiming at demonstrating the appropriateness of the proposed framework a simulation prototype was implemented and a validation approach was proposed consisting of simulation of scenarios, qualitative assessment and validation by research community peers.Recentemente a área de investigação das redes colaborativas tem vindo a debruçar-se na complexidade social e organizacional em ambientes colaborativos e como pode ser usada para prevenir falhas tecnológicas e consequentemente contribuir para redes colaborativas sustentáveis. Uma das direcções de estudo assenta na necessidade de fornecer sistemas amigáveis “humano-tecnológicos” com modelos cognitivos de factores humanos como o stress, emoção, confiança, liderança ou capacidade de tomada de decisão. É neste contexto que esta tese propõe um sistema baseado em emoções com o objectivo de oferecer outra aproximação para a gestão de conflitos e falhas da rede de colaboração. Esta abordagem, que pressupõe melhorar o desempenho das redes existentes, adopta alguns dos modelos desenvolvidos nas áreas da psicologia humana, sociologia e affective computing. A ideia que está subjacente é a de “pedir emprestado” o conceito de emoção humana e aplicá-lo no contexto das redes colaborativas, dando aos seus intervenientes a capacidade de “sentir emoções”. Assim, esta tese contribui com uma framework de modelação que conceptualiza a noção de “emoção” em redes colaborativas e com uma aproximação de metodologia sustentada em sistemas dinâmicos e baseada em agentes que estimam os “estados emocionais” dos participantes e da própria rede colaborativa. De forma a demonstrar o nível de adequabilidade da framework de modelação proposta, foi implementado um protótipo de simulação e foi proposta uma abordagem de validação consistindo em simulação de cenários, avaliação qualitativa e validação pelos pares da comunidade científica

Future manned systems advanced avionics study

COTS+ was defined in this study as commercial off-the-shelf (COTS) products, ruggedized and militarized components, and COTS technology. This study cites the benefits of integrating COTS+ in space, postulates a COTS+ integration methodology, and develops requirements and an architecture to achieve integration. Developmental needs and concerns were identified throughout the study; these needs, concerns, and recommendations relative to their abatement are subsequently presented for further action and study. The COTS+ concept appears workable in part or in totality. No COTS+ technology gaps were identified; however, radiation tolerance was cited as a concern, and the deferred maintenance issue resurfaced. Further study is recommended to explore COTS+ cost-effectiveness, maintenance philosophy, needs, concerns, and utility metrics. The generation of a development plan to further investigate and integrate COTS+ technology is recommended. A COTS+ transitional integration program is recommended. Sponsoring and establishing technology maturation programs and COTS+ engineering and standards committees are deemed necessary and are recommended for furthering COTS+ integration in space

Conceptual Models for Assessment & Assurance of Dependability, Security and Privacy in the Eternal CONNECTed World

This is the first deliverable of WP5, which covers Conceptual Models for Assessment & Assurance of Dependability, Security and Privacy in the Eternal CONNECTed World. As described in the project DOW, in this document we cover the following topics: • Metrics definition • Identification of limitations of current V&V approaches and exploration of extensions/refinements/ new developments • Identification of security, privacy and trust models WP5 focus is on dependability concerning the peculiar aspects of the project, i.e., the threats deriving from on-the-fly synthesis of CONNECTors. We explore appropriate means for assessing/guaranteeing that the CONNECTed System yields acceptable levels for non-functional properties, such as reliability (e.g., the CONNECTor will ensure continued communication without interruption), security and privacy (e.g., the transactions do not disclose confidential data), trust (e.g., Networked Systems are put in communication only with parties they trust). After defining a conceptual framework for metrics definition, we present the approaches to dependability in CONNECT, which cover: i) Model-based V&V, ii) Security enforcement and iii) Trust management. The approaches are centered around monitoring, to allow for on-line analysis. Monitoring is performed alongside the functionalities of the CONNECTed System and is used to detect conditions that are deemed relevant by its clients (i.e., the other CONNECT Enablers). A unified lifecycle encompassing dependability analysis, security enforcement and trust management is outlined, spanning over discovery time, synthesis time and execution time

Re-use of tests and arguments for assesing dependable mixed-critically systems

The safety assessment of mixed-criticality systems (MCS) is a challenging activity due to system heterogeneity, design constraints and increasing complexity. The foundation for MCSs is the integrated architecture paradigm, where a compact hardware comprises multiple execution platforms and communication interfaces to implement concurrent functions with different safety requirements. Besides a computing platform providing adequate isolation and fault tolerance mechanism, the development of an MCS application shall also comply with the guidelines defined by the safety standards. A way to lower the overall MCS certification cost is to adopt a platform-based design (PBD) development approach. PBD is a model-based development (MBD) approach, where separate models of logic, hardware and deployment support the analysis of the resulting system properties and behaviour. The PBD development of MCSs benefits from a composition of modular safety properties (e.g. modular safety cases), which support the derivation of mixed-criticality product lines. The validation and verification (V&V) activities claim a substantial effort during the development of programmable electronics for safety-critical applications. As for the MCS dependability assessment, the purpose of the V&V is to provide evidences supporting the safety claims. The model-based development of MCSs adds more V&V tasks, because additional analysis (e.g., simulations) need to be carried out during the design phase. During the MCS integration phase, typically hardware-in-the-loop (HiL) plant simulators support the V&V campaigns, where test automation and fault-injection are the key to test repeatability and thorough exercise of the safety mechanisms. This dissertation proposes several V&V artefacts re-use strategies to perform an early verification at system level for a distributed MCS, artefacts that later would be reused up to the final stages in the development process: a test code re-use to verify the fault-tolerance mechanisms on a functional model of the system combined with a non-intrusive software fault-injection, a model to X-in-the-loop (XiL) and code-to-XiL re-use to provide models of the plant and distributed embedded nodes suited to the HiL simulator, and finally, an argumentation framework to support the automated composition and staged completion of modular safety-cases for dependability assessment, in the context of the platform-based development of mixed-criticality systems relying on the DREAMS harmonized platform.La dificultad para evaluar la seguridad de los sistemas de criticidad mixta (SCM) aumenta con la heterogeneidad del sistema, las restricciones de diseño y una complejidad creciente. Los SCM adoptan el paradigma de arquitectura integrada, donde un hardware embebido compacto comprende múltiples plataformas de ejecución e interfaces de comunicación para implementar funciones concurrentes y con diferentes requisitos de seguridad. Además de una plataforma de computación que provea un aislamiento y mecanismos de tolerancia a fallos adecuados, el desarrollo de una aplicación SCM además debe cumplir con las directrices definidas por las normas de seguridad. Una forma de reducir el coste global de la certificación de un SCM es adoptar un enfoque de desarrollo basado en plataforma (DBP). DBP es un enfoque de desarrollo basado en modelos (DBM), en el que modelos separados de lógica, hardware y despliegue soportan el análisis de las propiedades y el comportamiento emergente del sistema diseñado. El desarrollo DBP de SCMs se beneficia de una composición modular de propiedades de seguridad (por ejemplo, casos de seguridad modulares), que facilitan la definición de líneas de productos de criticidad mixta. Las actividades de verificación y validación (V&V) representan un esfuerzo sustancial durante el desarrollo de aplicaciones basadas en electrónica confiable. En la evaluación de la seguridad de un SCM el propósito de las actividades de V&V es obtener las evidencias que apoyen las aseveraciones de seguridad. El desarrollo basado en modelos de un SCM incrementa las tareas de V&V, porque permite realizar análisis adicionales (por ejemplo, simulaciones) durante la fase de diseño. En las campañas de pruebas de integración de un SCM habitualmente se emplean simuladores de planta hardware-in-the-loop (HiL), en donde la automatización de pruebas y la inyección de faltas son la clave para la repetitividad de las pruebas y para ejercitar completamente los mecanismos de tolerancia a fallos. Esta tesis propone diversas estrategias de reutilización de artefactos de V&V para la verificación temprana de un MCS distribuido, artefactos que se emplearán en ulteriores fases del desarrollo: la reutilización de código de prueba para verificar los mecanismos de tolerancia a fallos sobre un modelo funcional del sistema combinado con una inyección de fallos de software no intrusiva, la reutilización de modelo a X-in-the-loop (XiL) y código a XiL para obtener modelos de planta y nodos distribuidos aptos para el simulador HiL y, finalmente, un marco de argumentación para la composición automatizada y la compleción escalonada de casos de seguridad modulares, en el contexto del desarrollo basado en plataformas de sistemas de criticidad mixta empleando la plataforma armonizada DREAMS.Kritikotasun nahastuko sistemen segurtasun ebaluazioa jarduera neketsua da beraien heterogeneotasuna dela eta. Sistema hauen oinarria arkitektura integratuen paradigman datza, non hardware konpaktu batek exekuzio plataforma eta komunikazio interfaze ugari integratu ahal dituen segurtasun baldintza desberdineko funtzio konkurrenteak inplementatzeko. Konputazio plataformek isolamendu eta akatsen aurkako mekanismo egokiak emateaz gain, segurtasun arauek definituriko jarraibideak jarraitu behar dituzte kritikotasun mistodun aplikazioen garapenean. Sistema hauen zertifikazio prozesuaren kostua murrizteko aukera bat plataformetan oinarritutako garapenean (PBD) datza. Garapen planteamendu hau modeloetan oinarrituriko garapena da (MBD) non modeloaren logika, hardware eta garapen desberdinak sistemaren propietateen eta portaeraren aurka aztertzen diren. Kritikotasun mistodun sistemen PBD garapenak etekina ateratzen dio moduluetan oinarrituriko segurtasun propietateei, adibidez: segurtasun kasu modularrak (MSC). Modulu hauek kritikotasun mistodun produktu-lerroak ere hartzen dituzte kontutan. Berifikazio eta balioztatze (V&V) jarduerek esfortzu kontsideragarria eskatzen dute segurtasun-kiritikoetarako elektronika programagarrien garapenean. Kritikotasun mistodun sistemen konfiantzaren ebaluazioaren eta V&V jardueren helburua segurtasun eskariak jasotzen dituzten frogak proportzionatzea da. Kritikotasun mistodun sistemen modelo bidezko garapenek zeregin gehigarriak atxikitzen dizkio V&V jarduerari, fase honetan analisi gehigarriak (hots, simulazioak) zehazten direlako. Bestalde, kritikotasun mistodun sistemen integrazio fasean, hardware-in-the-loop (Hil) simulazio plantek V&V iniziatibak sostengatzen dituzte non testen automatizazioan eta akatsen txertaketan funtsezko jarduerak diren. Jarduera hauek frogen errepikapena eta segurtasun mekanismoak egiaztzea ahalbidetzen dute. Tesi honek V&V artefaktuen berrerabilpenerako estrategiak proposatzen ditu, kritikotasun mistodun sistemen egiaztatze azkarrerako sistema mailan eta garapen prozesuko azken faseetaraino erabili daitezkeenak. Esate baterako, test kodearen berrabilpena akats aurkako mekanismoak egiaztatzeko, modelotik X-in-the-loop (XiL)-ra eta kodetik XiL-rako konbertsioa HiL simulaziorako eta argumentazio egitura bat DREAMS Europear proiektuan definituriko arkitektura estiloan oinarrituriko segurtasun kasu modularrak automatikoki eta gradualki sortzeko

Real-time scheduling in multicore : time- and space-partitioned architectures

Tese de doutoramento, Informática (Engenharia Informática), Universidade de Lisboa, Faculdade de Ciências, 2014The evolution of computing systems to address size, weight and power consumption (SWaP) has led to the trend of integrating functions (otherwise provided by separate systems) as subsystems of a single system. To cope with the added complexity of developing and validating such a system, these functions are maintained and analyzed as components with clear boundaries and interfaces. In the case of real-time systems, the adopted component-based approach should maintain the timeliness properties of the function inside each individual component, regardless of the remaining components. One approach to this issue is time and space partitioning (TSP)—enforcing strict separation between components in the time and space domains. This allows heterogeneous components (different real-time requirements, criticality, developed by different teams and/or with different technologies) to safely coexist. The concepts of TSP have been adopted in the civil aviation, aerospace, and (to some extent) automotive industries. These industries are also embracing multiprocessor (or multicore) platforms, either with identical or nonidentical processors, but are not taking full advantage thereof because of a lack of support in terms of verification and certification. Furthermore, due to the use of the TSP in those domains, compatibility between TSP and multiprocessor is highly desired. This is not the present case, as the reference TSP-related specifications in the aforementioned industries show limited support to multiprocessor. In this dissertation, we defend that the active exploitation of multiple (possibly non-identical) processor cores can augment the processing capacity of the time- and space-partitioned (TSP) systems, while maintaining a compromise with size, weight and power consumption (SWaP), and open room for supporting self-adaptive behavior. To allow applying our results to a more general class of systems, we analyze TSP systems as a special case of hierarchical scheduling and adopt a compositional analysis methodology.Fundação para a Ciência e a Tecnologia (FCT, SFRH/BD/60193/2009, programa PESSOA, projeto SAPIENT); the European Space Agency Innovation (ESA) Triangle Initiative program through ESTEC Contract 21217/07/NL/CB, Project AIR-II; the European Commission Seventh Framework Programme (FP7) through project KARYON (IST-FP7-STREP-288195)

Medical devices with embedded electronics: design and development methodology for start-ups

358 p.El sector de la biotecnología demanda innovación constante para hacer frente a los retos del sector sanitario. Hechos como la reciente pandemia COVID-19, el envejecimiento de la población, el aumento de las tasas de dependencia o la necesidad de promover la asistencia sanitaria personalizada tanto en entorno hospitalario como domiciliario, ponen de manifiesto la necesidad de desarrollar dispositivos médicos de monitorización y diagnostico cada vez más sofisticados, fiables y conectados de forma rápida y eficaz. En este escenario, los sistemas embebidos se han convertido en tecnología clave para el diseño de soluciones innovadoras de bajo coste y de forma rápida. Conscientes de la oportunidad que existe en el sector, cada vez son más las denominadas "biotech start-ups" las que se embarcan en el negocio de los dispositivos médicos. Pese a tener grandes ideas y soluciones técnicas, muchas terminan fracasando por desconocimiento del sector sanitario y de los requisitos regulatorios que se deben cumplir. La gran cantidad de requisitos técnicos y regulatorios hace que sea necesario disponer de una metodología procedimental para ejecutar dichos desarrollos. Por ello, esta tesis define y valida una metodología para el diseño y desarrollo de dispositivos médicos embebidos