An Architecture Pattern Enabling Safety at Lower Cost and with Higher Performance

International audienceIn both avionic and automotive systems, it might become very costly and/or restricting the functional performance, to prove functions safe in all operational conditions and for 100% of the mission time. This is especially true if the quality of sensor data and of communication data may vary very much. One way to solve this trade-off paradox is to leave part of the safety assessment from design-time to run-time. This paper proposes a general architectural pattern for this, and also how to instantiate this pattern in Integrated Modular Avionics (IMA) for the avionic domain, and in AUTOSAR for the automotive domain. The solutions imply some extensions of ARINC 653 and of AUTOSAR respectively, but they are not in conflict with the existing concepts. The proposed solutions are also fully in-line what is prescribed by the standards for functional safety of the two domains

On the calculation of time alignment errors in data management platforms for distribution grid data

The operation and planning of distribution grids require the joint processing of measurements from different grid locations. Since measurement devices in low- and medium-voltage grids lack precise clock synchronization, it is important for data management platforms of distribution system operators to be able to account for the impact of nonideal clocks on measurement data. This paper formally introduces a metric termed Additive Alignment Error to capture the impact of misaligned averaging intervals of electrical measurements. A trace-driven approach for retrieval of this metric would be computationally costly for measurement devices, and therefore, it requires an online estimation procedure in the data collection platform. To overcome the need of transmission of high-resolution measurement data, this paper proposes and assesses an extension of a Markov-modulated process to model electrical traces, from which a closed-form matrix analytic formula for the Additive Alignment Error is derived. A trace-driven assessment confirms the accuracy of the model-based approach. In addition, the paper describes practical settings where the model can be utilized in data management platforms with significant reductions in computational demands on measurement devices

Safety Kernel for cooperative sensor-based systems

Tese de mestrado em Segurança Informática, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2013Os sistemas críticos, usados em indústrias como a aeroespacial, aeronáutica ou automóvel, requerem novas soluções tecnológicas para responder à constante procura por novas funcionalidades que respondam aos novos desafios do futuro, tornando-se cada vez mais complexos. Estes sistemas necessitam, contudo, de respeitar elevados e rígidos requisitos, não só em termos de segurança na operação e fiabilidade, mas também em termos de requisitos de tamanho, peso e consumo energético. Arquiteturas tradicionais usadas no desenho deste tipo de sistemas críticos baseiam a segurança na operação possibilidade de provar, em tempo de desenvolvimento, que o sistema garante a previsibilidade necessária. Contudo, o aparecimento de novas tecnologias acarreta um aumento na complexidade das aplicações usadas, o que torna o objetivo de provar a sua fiabilidade uma tarefa árdua ou mesmo impossível, limitando as funcionalidades passíveis de serem integradas nestes sistemas. Por exemplo, o aparecimento de comunicações sem fios abriu um novo mundo de oportunidades: a mesma poderia permitir um conjunto de veículos comunicar e cooperar mutuamente para atingir um objetivo comum. Contudo, a incerteza que caracteriza este tipo de comunicações tem travado o desenvolvimento de aplicações passiveis de ser usados por sistemas críticos. Nesta tese, propomos uma arquitetura híbrida, constituída por componentes simples e previsíveis que coexistem com componentes complexos e imprevisíveis sem que isso, sem que essa coexistência ponha em causa as garantias de segurança na operação. A possibilidade de incluir novas aplicações, que façam uso de novas tecnologias, abre portas à introdução de novas funcionalidades em sistemas críticos, permitindo melhorar a performance e serviço prestado pelos sistemas atualmente existentes. A nossa arquitetura assenta num componente chamado Núcleo de Segurança (Safety Kernel), que tem como tarefa a monitorização dos requisitos de segurança e a gestão da configuração do sistema, assegurando-se que este se adapta às limitações observadas e que podem por em causa a segurança do sistema, evitando assim possíveis acidentes. Este documento descreve a arquitetura deste componente bem como a integração e interação do mesmo na arquitetura do sistema, apresentando a implementação de um protótipo do mesmo na arquitetura AIR - uma arquitetura baseada no conceito de compartimentação no espaço e tempo (CET) desenvolvida para sistemas aeroespaciais.Future safety-critical systems, used in, for example, the aerospacial, aeronautic and automotive industries, call for innovative computing architectures, with increased complexity. These systems must still cope with strict requirements, not only in terms of safety and reliability, but also in terms of size, weight and power consumption (SWaP). Traditional approaches used in the design of such critical systems, rely on proving and guaranteeing, at design time, the safety and predictability of their applications. However, with the emergence of new technological solutions and the increase of the complexity of applications, it gets harder or even infeasible to prove their safety by design, limiting the scope and possible features to include in such systems. For instance, the use of wireless communications opens a new world of possibilities: it may be used to develop smart vehicles that cooperate with each other to achieve some common goal. However, due to its uncertainty, the development of such applications for safety-critical systems turns out to be a challenging task. In this thesis, we propose a hybrid architecture, in which simple and predictable components coexist with complex and unpredictable ones, without compromising safety, despite the unavoidable uncertainty. The inclusion of complex components into safetycritical systems allows the emergence of new applications that provide new features or that improve the existing ones. Furthermore, we want to deal with the uncertainty that characterizes wireless communications and provide mechanisms which allow systems to cooperate with each other in a safe way. We rely on a component called Safety Kernel, in charge of monitoring and managing the runtime configuration of the system, forcing it to adapt to faults and runtime constraints in order to avoid hazardous situations. We describe the architecture and role of such Safety Kernel, and how they interact with other components in the system architecture, including the functional components of the control system. Finally we present a prototype implementation of such Safety Kernel over AIR, an architecture based on the concept of Time- and Space Partitioning (TSP) developed for aerospace systems

Proceedings. 27. Workshop Computational Intelligence, Dortmund, 23. - 24. November 2017

Dieser Tagungsband enthält die Beiträge des 27. Workshops Computational Intelligence. Die Schwerpunkte sind Methoden, Anwendungen und Tools für Fuzzy-Systeme, Künstliche Neuronale Netze, Evolutionäre Algorithmen und Data-Mining-Verfahren sowie der Methodenvergleich anhand von industriellen und Benchmark-Problemen