Dans les travaux existants, les analyses basées sur les modèles de la Sûreté de Fonctionnement (SdF) d'un système automatisé sont généralement focalisées uniquement sur la partie procédé. Aussi, les stratégies de reconfiguration du procédé - réalisées par le contrôle-commande - ne sont souvent pas modélisées, sinon de manière imprécises et sans échec possible. Pourtant, ces stratégies ont un impact certain sur la SdF du système bouclé, qui doit être pris en compte dans les modèles afin d'améliorer la pertinence des analyses. Le travail dont rend compte cette thèse contribue à la modélisation et à l'analyse de la SdF des systèmes dynamiques, réparables et reconfigurables. Premièrement, un nouveau formalisme de modélisation est proposé pour prendre en compte avec précision les différentes stratégies de reconfiguration du système avec leurs possibles échecs. Ce formalisme développe et généralise le principe des BDMP (Boolean logic Driven Markov Processes en anglais), auxquels il associe des machines de Moore afin de spécifier formellement les stratégies de reconfiguration. Dans un second temps, deux techniques d'analyse basées sur un modèle GBDMP (BDMP Généralisé) sont décrites. Ces techniques permettent d'obtenir un résultat qualitatif : l'ensemble des plus courtes Séquences de Coupe Minimales (SCM), ainsi qu'un résultat quantitatif : indicateur probabiliste de la disponibilité du système. Finalement, la modélisation GBDMP et l'analyse de SdF basée sur un modèle GBDMP sont expérimentées sur un cas d'étude représentatif de plusieurs problématiques industrielles liées au secteur de la production d'énergie électrique. / Existing works on Model Based Safety Analysis of an automated system generally focus on the process part. Process reconfiguration strategies that are driven by the control are often modeled without failure and with a lack of accuracy. However these strategies have a real impact on the safety of the closed-loop system. In order to improve the relevance of analysis, this impact has to be captured in models. This thesis contributes to modeling and analysis of dynamic repairable reconfigurable systems. Firstly a new modeling formalism is proposed to relevantly take into account different reconfiguration strategies that can fail. This formalism develops and generalizes the principle of Boolean logic Driven Markov Processes (BDMP), and enriches it with Moore machine for formally specifying reconfiguration strategies. In a second stage, two analysis techniques based on a Generalized BDMP (GBDMP) model are described. These techniques allow to obtain a qualitative result: the set of shortest Minimal Cut Sequences (MCS), and a quantitative result: probabilistic indicator of system availability. Finally, a case study coming from the electric power production field is addressed. This case study shows how several industrial problems can be solved in GBDMP framework.

Nous proposons de concevoir et de mettre en oeuvre un environnement logiciel pour une "gestion guidée par les modèles" des changements dans les architectures des applications distribuées coopératives. Les aspects adaptabilité des applications, les aspects transformations de graphe et les aspects particuliers des applications distribuées coopératives sont étudiés. Une approche d'adaptation s'appuyant sur une modélisation par les graphes et un style architectural de type Poducteur/Consommateur est présentée pour des applications communicantes collaboratives sensibles au contexte. Une démarche de raffinement est proposée permettant de garantir un certain degré d'adaptabilité en faisant un compromis entre les différents paramètres du contexte. Ces travaux de recherche ont aussi permis de définir un cadre algorithmique générique de reconfiguration architecturale multi-niveaux pour la sélection des architectures de déploiement les plus adaptées à un contexte et aux situations associées. Ce cadre a été appliqué au cas de la communication et de la coopération de groupe. Elle a aussi permis de modéliser le style architectural Producteur/Consommateur pour une communication orientée événement. Des règles d'adaptation ont été définies. Elles comportent une partie basée sur SWRL pour la description du contexte et des règles d'adaptation, et une partie basée sur les grammaires de graphes pour la transformation des configurations de déploiement / In this work, we study dynamic reconfiguration of collaborative communicating applications. Providing generic and scalable solutions for automated self-reconfiguration in group collaboration support systems can be driven by rule-based reconfiguration policies. To achieve this goal, we elaborate a dynamic graph-based modeling approach and we develop structural models that can represent the different interaction dependencies from different configuration-related point of views: communication flows between the distributed machines, the networked deployment nodes, and the service composition. Our solution is based on graph grammars rewriting. We provide graph transformation to specify rules for changing deployment architecture while being in conformance to an architectural style. In order to handle the complex design of communicating collaborative system architectures and the related adaptation issues, we propose a multi-layer modelling approach. This approach assures generic solutions for automatic context aware adaptation. Our approach is based on the observation that semantic data analysis that can be exploited to manage priorities and more generally to manage communications. This allows us to represent, in a richer way, the semantics of the managed systems

The focus of this thesis is on specialising the configuration of a field-programmable gate array (FPGA) to allow dynamic reconfiguration of real-time applications. The dynamic reconfiguration of an application has numerous advantages, but due to the overhead introduced by this process, it is only advantageous if the execution time exceeds reconfiguration time. This implies that dynamic reconfiguration is more suited to quasi-static applications, and real-time applications are therefore typically not reconfigured. A method proposed in the literature to ameliorate the overhead from the configuration process is to use a block-RAM (BRAM) based, hardware-controlled reconfiguration architecture, eliminating the need for a processor bus by storing the configuration in localised memory. The drawback of this architecture is the limited size of the BRAM, implying only a subset of configurations can be stored. The work presented in this thesis aim to address this size limitation by proposing a specialiser capable of adapting the configuration stored in the BRAM to represent different sets of hardware. This is done by directly manipulating the bits in the configuration using passive hardware. This not only allows the configuration to be specialised practically immediately, but also allows this specialiser to be device independent. By incorporating this specialiser into the BRAM-based architecture, this study sets out to establish that it is possible to reduce the overhead of the reconfiguration process to such an extent that dynamic reconfiguration can be used for real-time applications. Since the composition of the configuration is not publicly available, a method had to be found to parse and analyse the configuration in order to map the configuration space of the device. The approach used was to compare numerous different configurations and mapping the differences. By analysing these differences, it was found that there is a logical relationship between the slice coordinates and the configuration space of the device. The encoding of the lookup tables was also determined from their initialisation parameters. This allows the configuration of any lookup table to be changed by simply changing the corresponding bits in the configuration. Using this proposed reconfiguration architecture, a distributed multiply-accumulate was reconi figured and its functional density measured. The reason for selecting this specific application is because the multiply-accumulate instruction can be found at the heart of many real-time applications. If the functional density of the reconfigured application is comparable to those of its static equivalent, a strong case can be made for real-time reconfiguration in general. Functional density is an indication of the composite benefits dynamic reconfiguration obtains above its static generic counterpart. Due to the overhead of the reconfiguration process, the functional density of reconfigured applications is traditionally significantly lower than those of static applications. If the functional density of the reconfigured application can rival those of the static equivalent, the overhead from the reconfiguration process becomes negligible. Using this metric, the functional density of the distributed multiply-accumulate was compared for different reconfiguration implementations. It was found that the reconfiguration architecture proposed in this thesis yields a significant improvement over other reconfiguration methods. In fact, the functional density of this method rivalled that of its static equivalent, implying that it is possible to dynamically reconfigure a real-time application. It was also found that the proposed architecture reduces specialisation and reconfiguration time to such an extent that it is possible complete the reconfiguration process within strict time constraints. Even though the proposed method is only capable of reconfiguring the LUTs of a real-time application, this is the first step towards allowing full reconfiguration of applications with dynamic characteristics. The first contribution this thesis makes is a novel method to parse and analyse the configuration of a XilinxR VirtexR -5 FPGA. It also successfully maps the configuration space to the configuration data. Even though this method is applied to a specific device, it is device independent and can easily be applied to any other FPGA. The second contribution comes from using the information obtained from this analysis to design and implement a configuration specialiser, capable of adapting lookup tables in real time. Lastly, the third contribution combines this specialiser with the BRAM-based architecture to allow the reconfiguration of applications typically not reconfigured. / PhD (Computer and Electronic Engineering), North-West University, Potchefstroom Campus, 2015

The focus of this thesis is on specialising the configuration of a field-programmable gate array (FPGA) to allow dynamic reconfiguration of real-time applications. The dynamic reconfiguration of an application has numerous advantages, but due to the overhead introduced by this process, it is only advantageous if the execution time exceeds reconfiguration time. This implies that dynamic reconfiguration is more suited to quasi-static applications, and real-time applications are therefore typically not reconfigured. A method proposed in the literature to ameliorate the overhead from the configuration process is to use a block-RAM (BRAM) based, hardware-controlled reconfiguration architecture, eliminating the need for a processor bus by storing the configuration in localised memory. The drawback of this architecture is the limited size of the BRAM, implying only a subset of configurations can be stored. The work presented in this thesis aim to address this size limitation by proposing a specialiser capable of adapting the configuration stored in the BRAM to represent different sets of hardware. This is done by directly manipulating the bits in the configuration using passive hardware. This not only allows the configuration to be specialised practically immediately, but also allows this specialiser to be device independent. By incorporating this specialiser into the BRAM-based architecture, this study sets out to establish that it is possible to reduce the overhead of the reconfiguration process to such an extent that dynamic reconfiguration can be used for real-time applications. Since the composition of the configuration is not publicly available, a method had to be found to parse and analyse the configuration in order to map the configuration space of the device. The approach used was to compare numerous different configurations and mapping the differences. By analysing these differences, it was found that there is a logical relationship between the slice coordinates and the configuration space of the device. The encoding of the lookup tables was also determined from their initialisation parameters. This allows the configuration of any lookup table to be changed by simply changing the corresponding bits in the configuration. Using this proposed reconfiguration architecture, a distributed multiply-accumulate was reconi figured and its functional density measured. The reason for selecting this specific application is because the multiply-accumulate instruction can be found at the heart of many real-time applications. If the functional density of the reconfigured application is comparable to those of its static equivalent, a strong case can be made for real-time reconfiguration in general. Functional density is an indication of the composite benefits dynamic reconfiguration obtains above its static generic counterpart. Due to the overhead of the reconfiguration process, the functional density of reconfigured applications is traditionally significantly lower than those of static applications. If the functional density of the reconfigured application can rival those of the static equivalent, the overhead from the reconfiguration process becomes negligible. Using this metric, the functional density of the distributed multiply-accumulate was compared for different reconfiguration implementations. It was found that the reconfiguration architecture proposed in this thesis yields a significant improvement over other reconfiguration methods. In fact, the functional density of this method rivalled that of its static equivalent, implying that it is possible to dynamically reconfigure a real-time application. It was also found that the proposed architecture reduces specialisation and reconfiguration time to such an extent that it is possible complete the reconfiguration process within strict time constraints. Even though the proposed method is only capable of reconfiguring the LUTs of a real-time application, this is the first step towards allowing full reconfiguration of applications with dynamic characteristics. The first contribution this thesis makes is a novel method to parse and analyse the configuration of a XilinxR VirtexR -5 FPGA. It also successfully maps the configuration space to the configuration data. Even though this method is applied to a specific device, it is device independent and can easily be applied to any other FPGA. The second contribution comes from using the information obtained from this analysis to design and implement a configuration specialiser, capable of adapting lookup tables in real time. Lastly, the third contribution combines this specialiser with the BRAM-based architecture to allow the reconfiguration of applications typically not reconfigured. / PhD (Computer and Electronic Engineering), North-West University, Potchefstroom Campus, 2015

Au cours des dernières années, le cinéma tridimensionnel a connu un regain de popularité. La réalisation de plusieurs films d'animation 3D de qualité, de même que le succès fulgurant du film Avatar aura permis au grand public de constater la qualité de cette nouvelle génération de technologies 3D. Cependant, un problème fondamental ralentit toujours l'adoption à la maison de ce mode de divertissement. En effet, tout contenu visuel produit en se basant sur des techniques de stéréoscopie subira des distorsions visuelles lorsqu'observé dans des conditions différentes de celles considérées lors de la création du contenu. Autrement dit, un film 3D tourné pour un cinéma de grande dimension n'aura pas une richesse de profondeur aussi grande lorsqu'il sera visualisé sur un écran domestique. Ce mémoire présente un cadre de travail, un modèle mathématique et un ensemble de techniques permettant de"reconfigurer", en générant de nouvelles images, le contenu stéréoscopique original afin que l'effet de profondeur original soit préservé dans les nouvelles conditions de visualisation.

L'utilisation de réseaux de capteurs sans-fils (RCSF) se développe dans de nombreux domaines où l'informatique doit être intégrée au plus proche de l'environnement. Ce principe appelé informatique omniprésente se popularise par des applications dans de multiples domaines, de la domotique à l'étude d'environnements naturels en passant par la régulation des transports ou encore la surveillance de bâtiments à risques. Si les RCSF présentent de bonnes perspectives pour le domaine de l'informatique omniprésente, le matériel utilisé présente souvent des capacités très limitées et il est souvent compliqué de développer des applications ou de configurer de tels réseaux. Des travaux récemment réalisés au laboratoire DOMUS amènent la vision d'une informatique omniprésente autonome qui permettrait à plusieurs éléments d'un réseau de s'organiser entre eux pour limiter les interventions humaines. Dans cette vision, la reprogrammation dynamique des noeuds est utilisée pour simplifier et alléger le processus de reconfiguration du réseau. Le présent projet s'est donc intéressé à la problématique de la reprogrammation des noeuds du réseau dans une optique future d'informatique omniprésente autonome adaptée aux RCSF. Le présent projet de maîtrise a permis dans un premier temps de mettre en place un cadriciel de programmation par composants adapté aux ressources contraintes des RCSF. Ce système de programmation par composants (POC) appelé Nodecom se place comme une amélioration par rapport aux solutions de POC déjà existantes. En effet, Nodecom présente la première architecture hybride permettant à la fois de programmer en utilisant des composants statiques et à la fois de pouvoir charger de nouveaux composants de manière dynamique. Cette architecture hybride a permis d'alléger l'impact du système de programmation par composants tout en conservant la possibilité de reprogrammer dynamiquement certains composants. Dans un second temps, le projet a consisté à réaliser un dépôt distribué de composants qui permet à chaque noeud de charger dynamiquement n'importe quel composant publié à travers le réseau. Dans ce dépôt distribué, chaque noeud peut se voir attribuer le rôle de conserver une copie d'un fichier de composant dans sa mémoire locale. Pour ce faire, l'implémentation réalisée repose sur un algorithme de routage par clé inspiré des réseaux pair-à-pair traditionnels et adapté aux contraintes des plateformes utilisées. Les résultats de l'évaluation de ce système de composants distribué pour les réseaux de capteurs sans-fils sont encourageants puisqu'ils mettent en évidence les faibles besoins en mémoire du système. L'implémentation réalisée dans ce projet se place alors comme un bon support pour les travaux futurs qui chercheront à adapter la vision d'informatique omniprésente autonome au contexte des réseaux de capteurs sans-fils.

Self-reconfigurable robotic systems are variable-morphology machines capable of changing their overall structure by rearranging the modules they are composed of. Individual modules are capable of connecting and disconnecting to and from one another, which allows the robot to adapt to changing environments. Optimally reconfiguring such systems is computationally prohibitive and thus in general self-reconfiguration approaches aim at approximating optimal solutions. Nonetheless, even for approximate solutions, centralized methods scale poorly in the number of modules. Therefore, the objective of this research is the development of decentralized self-reconfiguration methods for modular robotic systems. Building on completeness results of the centralized algorithms in this work, decentralized methods are developed that guarantee stochastic convergence to a given target shape. A game-theoretic approach lays the theoretical foundation of a novel potential game-based formulation of the self-reconfiguration problem. Furthermore, two extensions to the basic game-theoretic algorithm are proposed that enable agents to modify the algorithms' parameters during runtime and improve convergence times. The flexibility in the choice of utility functions together with runtime adaptability makes the presented approach and the underlying theory suitable for a range of problems that rely on decentralized local control to guarantee global, emerging properties. The experimental evaluation of the presented algorithms relies on a newly developed multi-robotic testbed called the "Robotarium" that is equipped with custom-designed miniature robots, the "GRITSBots". The Robotarium provides hardware validation of self-reconfiguration on robots but more importantly introduces a novel paradigm for remote accessibility of multi-agent testbeds with the goal of lowering the barrier to entrance into the field of multi-robot research and education.

Thesis (DTh (Practical Theology and Missiology))--University of Stellenbosch, 2008. / This dissertation aims to analyse and evaluate the traditional Malawian Choral music as sung by young people in the Church of Central Africa Presbyterian (CCAP) Nkhoma Synod with careful and critical consideration of the theological–liturgical outcomes. Such an analysis and evaluation reveals the neglected areas and the implications thereof for the Church, in aid of serving effectively her members. This will enrich and advance contextual theology as well as the liturgy in the Church. Chapter 2 discusses the approach the writers of Mark and Philippians took to fit into the new situations in which they were. This chapter functions as the basis for the subsequent chapters, as it tries to show how reinterpretation could have taken place. In so doing, a living expression of a living reality, which was reinterpreted in a particular place, at a particular time, for a particular purpose, will be noted in a reconfigured state. Chapter 3 will give an overview of theological–liturgical development in Malawi, and how the Gospel was brought in the light of the liturgy that evangelization assumed. The aftermath of traditional theology will then be assessed, including the impact of traditional theology on the Malawian people. Subsequently, the possibilities of coming up with a theology and a liturgy that is sensitive to the users are discussed. Chapter 4 examines traditional Malawian Choral music before the arrival of Christianity. A discussion of the way missionaries used English/Scottish music without blending it with the traditional music in the liturgy then follows. The consequence of such type of liturgizing and the initiative in the development of both English/Scottish, as well as traditional Malawian music will be shown. Chapter 5 provides an empirical study on what the young people in Malawi are singing in the CCAP-Nkhoma Synod by means of some sample areas. This includes an examination of possible influences that are compelling the young people to compose and sing these songs. This examination comprises an analysis of songs, the themes that are developing, and the reason for such themes. Chapter 6 contains suggestions for hymnological development in Malawi, based on the findings of the empirical study. This thesis acknowledges the importance of reinterpretation because of different confrontations that an individual or group experiences. To achieve this, a process of reconfiguration that involves re-interpretation and blending has been suggested and discussed. This dissertation will discuss the dialectic of experience and interpretation as regards continuous experiences of humankind due to new challenges. Such an approach provides the framework for the investigation of current experiences of present readers of the New Testament in relation to the first Christians’ experiences, which forced the reshaping of that symbolic world due to new religious convictions and experiences.

The work of this thesis is concerned with the aggregation and advancement of modelling practise as used within modern day product development and optimisation environments making use of Model Based Design ('MBD') and similar procedures. A review of model development and use forms the foundation of the work, with the findings being aggregated into two unique approaches for rapid model development and reconfiguration; the Plug-and-Simulate ('PaS') approach and the Paradigm for Large Model Creation ('PLMC'); each shown to posses its own advantages. To support the MBD process a model optimisation algorithm that seeks to eliminate parameters that are of little or no significance to a simulation is developed. Eliminations are made on the basis of an energy analysis which determines the activity of a number of energy elements. Low activity elements are said to be of less significance to the global dynamics of a model and thus become targets for elimination. A model configuration tool is presented that brings together the PLMC and parameter elimination algorithm. The tool is shown to be useful for rapid configuration and reconfiguration of models and is capable of automatically running the optimisation algorithms thus producing a simulation model that is parametrically and computationally optimised. The response of the plug-and-simulate drivetrain submodels, assembled to represent a front wheel drive drivetrain, is examined. The resulting model is subjected to a torque step-input and an empirically obtained torque curve that characterises the input to a drivetrain undergoing steady acceleration. The model displays the expected response in both its full parameter and parameter reduced versions with simulation efficiency gains observed in the parameter reduced version.

In this thesis, a retail market mechanism that provides differentiated reliability services is proposed. The differentiated reliability services beyond the standard level utilize advanced metering infrastructure, automated distribution reconfiguration and distributed generation (DG). The service quality at the standard level is regulated, while high reliability services are offered through a market mechanism. This proposed market mechanism is designed in two different models of managing the distribution networks. The first model assumes that an independent distribution system operator (DSO) as an administrative firm provides operational support for delivery and reliability services in a retail market, while the second model does not have a DSO. Main reliability market participants are distribution utilities, retail electricity providers (REPs), non-utility-owned DG units, and end users. The REPs, as end users’ representatives and aggregators, purchase delivery service with high reliability level and backup power from the utilities and DG units, respectively. The prices for these services are based on bidding by all market participants. Bids are created by each market participant optimizing its objective with respect to its own interests; therefore, the market participant can assess the investment costs and manage its own risk in setting the service charge. Notably, the proposed market mechanism, which is based on knowing customers’ willingness to pay, and preferences for reliability, aims to give long-term investment signals to service providers for planning investments in new technologies at value. In addition, the provision of high reliability services can be considered a means that enables the service providers to improve system resilience. The modified IEEE Roy Billinton Test System Bus 2 is simulated to demonstrate proof-of-concept for the proposed retail market by showing the iii process of settling the service prices and utilities’ expected compensation design. By comparing the settled service prices between the two market models, we show that the service prices are quite similar, but the number of end users obtaining backup power is different.