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Ce document présente nos contributions aux algorithmes d'ordonnancement à criticité mixte pour multi-processeurs. La correction de l'exécution des applications temps réel critiques est assurée par l'utilisation d'un ordonnancement vérifié à la conception. Dans ce contexte, le dimensionnement des plate-formes d'exécution vise à minimiser le nombre de processeurs nécessaires pour assurer un ordonnancement correct. Ce dimensionnement est affecté par les exigences de sûreté de fonctionnement. Ces exigences poussent à surestimer le temps nécessaire garantissant l'exécution correcte des applications. Il en découle un dimensionnement assez coûteux. Les méthodes d'ordonnancement des systèmes à criticité mixte proposent des compromis sur les garanties d'exécution des applications améliorant le dimensionnement. Différents compromis ont été proposés mais tous reposent sur la notion de mode d'exécution. Les modes sont ordonnés, et les tâches voient leur temps d'exécution requis croître avec les modes. Cependant, afin de diminuer le dimensionnement du système, seul l'ordonnancement des tâches les plus critiques est garanti. Ce modèle est appelé "discarding". La majorité des algorithmes proposés se limitent à deux modes d'exécutions par simplicité. De plus, les algorithmes les plus efficaces pour multi-processeurs exhibent un nombre élevé de préemptions, ce qui constitue un frein à leur adoption. Finalement, ces algorithmes sont rarement généralisables. Pourtant, la prise en compte de plus de deux modes, ou de tâches aux périodes élastiques permettrait une adoption plus large par le milieu industriel. L'approche proposée repose sur la séparation des préoccupations entre la prise en compte des modes de fonctionnement, et l'ordonnancement des tâches sur multi-processeurs. Cette méthode permet de concevoir une politique d'ordonnancement efficace et adaptable à différents modèles de systèmes à criticité mixte. Notre approche consiste à transformer un lot de tâches à criticité mixte en un lot de tâches qui n'est plus à criticité mixte. Ceci nous permet d'utiliser un algorithme d'ordonnancement temps réel optimal engendrant peu de préemptions et de migrations, à savoir RUN. Cette approche, appliquée en premier pour le modèle discarding avec deux modes d'exécution, rempli son objectif d'efficacité. Nous illustrons sa généricité en utilisant le même principe pour ordonnancer des systèmes discarding avec plus de deux modes d'exécution. Enfin, une démarche reposant sur la décomposition de tâche permet de généraliser l'approche au cas des tâches élastiques. / This thesis focuses on the scheduling of mixed-criticality scheduling algorithms for multi-processors. The correctness of the execution of the real-time applications is ensured by a scheduler and is checked during the design phase. The execution platform sizing aims at minimising the number of processors required to ensure this correct scheduling. This sizing is impacted by the safety requirements. Indeed, these requirements tend to overestimate the execution times of the applications to ensure their correct executions. Consequently, the resulting sizing is costly. The mixed-criticality scheduling theory aims at proposing compromises on the guarantees of the execution of the applications to reduce this over-sizing. Several models of mixed-criticality systems offering different compromises have been proposed but all are based on the use of execution modes. Modes are ordered and tasks have non decreasing execution times in each mode. Yet, to reduce the sizing of the execution platform, only the execution of the most critical tasks is ensured. This model is called the discarding model. For simplicity reasons, most of the mixed-criticality scheduling algorithms are limited to this model. Besides, the most efficient scheduling policies for multi-processors entail too many preemptions and migrations to be actually used. Finally, they are rarely generalised to handle different models of mixed-criticality systems. However, the handling of more than two execution modes or of tasks with elastic periods would make such solutions more attractive for the industry. The approach proposed in this thesis is based on the separation of concerns between handling the execution modes and the scheduling of the tasks on the multi-processors. With this approach, we achieve to design an efficient scheduling policy that schedules different models of mixed-criticality systems. It consists in performing the transformation of a mixed-criticality task set into a non mixed-criticality one. We then schedule this task set by using an optimal hard real-time scheduling algorithm that entails few preemptions and migrations: RUN. We first apply our approach on the discarding model with two execution modes. The results show the efficiency of our approach for such model. Then, we demonstrate the versatility of our approach by scheduling systems of the discarding model with more than two execution modes. Finally, by using a method based on the decomposition of task execution, our approach can schedule systems based on elastic tasks.

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Together with electrification of the transportation sector and the introduction of renewable energy in the electricity grid, the demand for lithium-ion batteries is increasing. As a result of this emerging need, large-scale battery manufacturing is a promising and developing industry. Currently, there exist a challenge for lithium-ion battery manufacturers to ensure supply of the desired material and to guarantee operation in a sustainable manner. The material included in a battery cell possess unique characteristics, has high criticality, and experience limited availability, which has resulted in an un- certain business environment with high complexity. Hence, the aim of this thesis is to investigate how unique material characteristics affect the purchasing environment and can be considered to obtain a sustainable inbound supply chain for lithium-ion battery manufacturers. The study is based on the following research question; How can purchasing of critical direct material for lithium-ion battery manufacturers support a sustainable inbound supply chain?

yes / In modern chemical plants, it is essential to establish an effective maintenance strategy which will deliver financially driven results at optimised conditions, that is, minimum cost and time, by means of a criticality review of equipment in maintenance. In this article, a fuzzy logic-based criticality assessment system (FCAS) for the management of a local company’s equipment maintenance is introduced. This fuzzy system is shown to improve the conventional crisp criticality assessment system (CCAS). Results from case studies show that not only can the fuzzy logic-based system do what the conventional crisp system does but also it can output more criticality classifications with an improved reliability and a greater number of different ratings that account for fuzziness and individual voice of the decision-makers.

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A Cyber-physical System (CPS) can be described as a network of interlinked, concurrent computational components that interact with the physical world. Such a system is usually of reactive nature and must satisfy strict timing requirements to guarantee a correct behaviour. The components can be of mixed-criticality which implies different progress models and communication models, depending whether the focus of a component lies on predictability or resource efficiency. In this dissertation I present a novel approach that bridges the gap between stream processing models and Labelled Transition Systems (LTSs). The former offer powerful tools to describe concurrent systems of, usually simple, components while the latter allow to describe complex, reactive, components and their mutual interaction. In order to achieve the bridge between the two domains I introduce the novel LTS Synchronous Interface Automaton (SIA) that allows to model the interaction protocol of a process via its interface and to incrementally compose simple processes into more complex ones while preserving the system properties. Exploiting these properties I introduce an analysis to identify permanent blocking situations in a network of composed processes. SIAs are wrapped by the novel component-based coordination model Process Network with Synchronous Communication (PNSC) that allows to describe a network of concurrent processes where multiple communication models and the co-existence and interaction of heterogeneous processes is supported due to well defined interfaces. The work presented in this dissertation follows a holistic approach which spans from the theory of the underlying model to an instantiation of the model as a novel coordination language, called Streamix. The language uses network operators to compose networks of concurrent processes in a structured and hierarchical way. The work is validated by a prototype implementation of a compiler and a Run-time System (RTS) that allows to compile a Streamix program and execute it on a platform with support for ISO C, POSIX threads, and a Linux operating system.

Submitted by Adriene Marchiori (adrienemarchiori@yahoo.com.br) on 2017-06-12T14:51:38Z No. of bitstreams: 1 FACED_DISSERTAÇÃO-YURI BASTOS WANDERLEY.pdf: 2278085 bytes, checksum: 52191a30f859e881aa5813660b1a7521 (MD5) / Approved for entry into archive by Maria Auxiliadora da Silva Lopes (silopes@ufba.br) on 2017-06-13T10:30:50Z (GMT) No. of bitstreams: 1 FACED_DISSERTAÇÃO-YURI BASTOS WANDERLEY.pdf: 2278085 bytes, checksum: 52191a30f859e881aa5813660b1a7521 (MD5) / Made available in DSpace on 2017-06-13T10:30:50Z (GMT). No. of bitstreams: 1 FACED_DISSERTAÇÃO-YURI BASTOS WANDERLEY.pdf: 2278085 bytes, checksum: 52191a30f859e881aa5813660b1a7521 (MD5) / Por atender, em sua maioria, jovens das classes populares, as Redes Públicas de Ensino podem desempenhar um papel estratégico na diminuição das barreiras impostas por condições históricas e culturais, provenientes das desigualdades sociais e econômicas, que limitam um maior potencial das apropriações tecnológicas por parte dos jovens das classes populares. O desafio não é apenas incluir a escola pública e a sua comunidade no mundo da tecnologia por meio da distribuição de equipamentos, mas contribuir para a construção de bases pedagógicas, técnicas e políticas que possibilitem e estimulem apropriações tecnológicas críticas, contextualizadas e colaborativas, dentro e fora das escolas. A pesquisa teve como objeto de estudo o Programa de Difusão de Mídias e Tecnologias Educacionais da Rede Pública Estadual de Ensino da Bahia, a Rede Anísio Teixeira, no qual o pesquisador atua como educador e gestor. Por meio de um Estudo de Caso inspirado na Etnopesquisa Crítica e Implicada e a Pesquisa da Experiência propostas por Macedo (2009, 2010 e 2015), buscou compreender as experiências vivenciadas pelos educadores nos processos de gestão, formação, produção e compartilhamento de Mídias e Tecnologias Educacionais Livres desenvolvidos no Programa. Ao considerar as experiências dos educadores como principais elementos de seu exercício de compreensão, a pesquisa trouxe para o centro da discussão as relações humanas, suas compreensões e implicações. Experiências vivenciadas no contexto de um programa de governo, orientado por uma proposta de apropriação tecnológica nos processos de ensino e aprendizagem, que se inspira na criticidade, na contextualização e na colaboração. Apesar de ser um programa de difusão tecnológica, as experiências dos educadores da Rede Anísio Teixeira, mostraram que as tecnologias não precisam ser compreendidas como o fim em si, mas como linguagens que promovem relações, permeadas por desafios e potencialidades, oportunidades e ameaças, que podem ser apropriadas pela comunidade escolar como dispositivos políticos de afirmação social, histórica e cultural. / ABSTRACT By mostly assisting young people of the popular classes, the public-school system can play a strategic role in reducing the barriers imposed by historical and cultural conditions, resulting from social and economic inequalities, which limit the greater potential of technological appropriations by the popular classes teenagers. The challenge is not only to include public schools and their communities in the technological world by distributing equipment, but to contribute to the construction of pedagogical, technical and political bases that allow and stimulate critical, contextualized and collaborative technological appropriations inside and outside school. This research had as its object of study the “Rede Anísio Teixeira”, which is the Educational Media and Technologies Dissemination Program of Bahia’s Public School System, in which the researcher acts as an educator and manager. Through a case study inspired by the critical and involved “ethnoresearch” and the experience research proposed by Macedo (2009, 2010 and 2015), he sought to understand the experiences lived by educators in the processes of management, formation, production and sharing of Free Educational Media and Technologies developed in the Program. In considering the experiences as the main element of its exercise of understanding, the research brought to the center of the discussion the human relationships, their understandings and implications. Experiences lived in the context of a government program, guided by a proposal of technological appropriation in the teaching and learning processes, which is inspired by criticality, contextualization and collaboration. Although it is a technological dissemination program, the experiences of “Rede Anísio Teixeira” educators have shown that technologies need not be understood as an end in themselves, but as languages that foster relationships, permeated by challenges and potentialities, opportunities and threats, that can be appropriated by the school community as political devices of social, historical and cultural affirmation.

About 60 percent of the electricity production in Belgium originates from nuclear power plants. Belgium owns 7 nuclear pressurized water reactors, which are located in two sites: 4 reactors in Doel and 3 reactors in Tihange. Together they have a capacity of approximately 5900 MWe. All these reactors use classical uranium oxide fuel assemblies. Two of them (Doel3, Tihange2) have also accepted a limited number of mixed (uranium and plutonium) oxide fuel assemblies. These mixed fuel assemblies came from the reprocessing of spent uranium oxide fuel assemblies in La Hague (France). The reprocessing of spent fuel gives birth to vitrified high-level waste, and to different isotopes of uranium and plutonium, which can be used in the manufacture of mixed oxide fuel assemblies. Each country producing radioactive waste must find a solution to dispose them safely. The internationally accepted solution is to dispose high-level radioactive waste in a deep and stable geological layer. This seems to be the most secure and environment-friendly way to get rid of the high-level radioactive waste. One of the few stable geological layers, which could accept radioactive waste in Belgium, is the Boom clay layer. Another possible layer is the Ypresian clay layer, but it is not the reference option for the moment. The Boom clay layer is quite thin (about 100 m thick) and is not at a large depth (about 240 m below the ground surface) at the proposed disposal site, beneath the SCK CEN Nuclear Research Centre in Mol. A large number of studies have already been performed on the Boom clay layer, and on the possibility of building a high-level radioactive waste repository in this geological medium. Since 1993, the Belgian government has promulgated a moratorium on the reprocessing of spent uranium oxide fuels in La Hague. Since then, spent fuel assemblies are considered as waste, and ONDRAF/NIRAS (the Belgium Agency for Radioactive Waste and Enriched Fissile Materials) has thus to deal with them as waste. This rises a number of questions on how to deal with this new kind of waste. A solution is to directly dispose these spent fuel assemblies in containers in a repository, just like the other high-level radioactive waste. This repository would be build in the Boom clay layer at a depth of about 240 m beneath the SCK CEN. One of the questions raised by this new kind of waste is: "could the direct disposal of the spent nuclear fuel assemblies lead to nuclear criticality risks in the future?". Nuclear criticality is the ability of a system to sustain a nuclear fission chain reaction. This question was not a key issue with vitrified high-level waste because these do not include fissile uranium and plutonium isotopes, which could lead to a criticality event. The spent fuel repository will be designed in order to totally avoid the occurrence of a criticality event at the closure time. But in the future history of the repository, external events could possibly affect this. These events could maybe lead to criticality inside the repository, and this has also to be avoided. This work tries to answer this question, and to determine how to avoid a long-term criticality event inside the repository. The only complete research work answering this question has been performed in the U.S. for the Yucca Mountain repository but this design is fully different from the Belgian one studied here: for example, the waste are not only spent fuel waste, and the geological layer is volcanic tuff.<p>The main achievements of this work are: <p>*A first set of in-package criticality scenarios for different design options for a Belgian spent fuel repository in the Boom clay layer. <p>*A large number of criticality calculations with different parameters (fuel type, fuel burnup, fuel enrichment, distance between the fuel assemblies, distance between the fuel rods, water fraction inside the overpack) for the different design options. <p>*A preliminary study of the effects of the spent fuel assemblies isotopic evolution with time on the multiplication factor. <p>*For the first time, a coupling between the in-package criticality scenarios and the criticality calculations has been performed. / Doctorat en sciences appliquées / info:eu-repo/semantics/nonPublished