With increasing number of applications in Internet and mobile environments, distributed software systems are demanded to be more powerful and flexible, especially in terms of dynamism and security. This dissertation describes my work concerning three aspects: dynamic reconfiguration of component software, security control on middleware applications, and web services dynamic composition. <br><br> Firstly, I proposed a technology named Routing Based Workflow (RBW) to model the execution and management of collaborative components and realize temporary binding for component instances. The temporary binding means component instances are temporarily loaded into a created execution environment to execute their functions, and then are released to their repository after executions. The temporary binding allows to create an idle execution environment for all collaborative components, on which the change operations can be immediately carried out. The changes on execution environment will result in a new collaboration of all involved components, and also greatly simplifies the classical issues arising from dynamic changes, such as consistency preserving etc. <br><br> To demonstrate the feasibility of RBW, I created a dynamic secure middleware system - the Smart Data Server Version 3.0 (SDS3). In SDS3, an open source implementation of CORBA is adopted and modified as the communication infrastructure, and three secure components managed by RBW, are created to enhance the security on the access of deployed applications. SDS3 offers multi-level security control on its applications from strategy control to application-specific detail control. For the management by RBW, the strategy control of SDS3 applications could be dynamically changed by reorganizing the collaboration of the three secure components. <br><br> In addition, I created the Dynamic Services Composer (DSC) based on Apache open source projects, Apache Axis and WSIF. In DSC, RBW is employed to model the interaction and collaboration of web services and to enable the dynamic changes on the flow structure of web services. <br><br> Finally, overall performance tests were made to evaluate the efficiency of the developed RBW and SDS3. The results demonstrated that temporary binding of component instances makes slight impacts on the execution efficiency of components, and the blackout time arising from dynamic changes can be extremely reduced in any applications. / Heutige Softwareanwendungen fuer das Internet und den mobilen Einsatz erfordern bezueglich Funktionalitaet und Sicherheit immer leistungsstaerkere verteilte Softwaresysteme. Diese Dissertation befasst sich mit der dynamischen Rekonfiguration von Komponentensoftware, Sicherheitskontrolle von Middlewareanwendungen und der dynamischen Komposition von Web Services. <br><br> Zuerst wird eine Routing Based Workflow (RBW) Technologie vorgestellt, welche die Ausfuehrung und das Management von kollaborierenden Komponenten modelliert, sowie fuer die Realisierung einer temporaeren Anbindung von Komponenteninstanzen zustaendig ist. D.h., Komponenteninstanzen werden zur Ausfuehrung ihrer Funktionalitaet temporaer in eine geschaffene Ausfuehrungsumgebung geladen und nach Beendigung wieder freigegeben. Die temporaere Anbindung erlaubt das Erstellen einer Ausfuehrungsumgebung, in der Rekonfigurationen unmittelbar vollzogen werden koennen. Aenderungen der Ausfuehrungsumgebung haben neue Kollaborations-Beziehungen der Komponenten zufolge und vereinfachen stark die Schwierigkeiten wie z.B. Konsistenzerhaltung, die mit dynamischen Aenderungen verbunden sind. <br><br> Um die Durchfuehrbarkeit von RBW zu demonstrieren, wurde ein dynamisches, sicheres Middleware System erstellt - der Smart Data Server, Version 3 (SDS3). Bei SDS3 kommt eine Open Source Softwareimplementierung von CORBA zum Einsatz, die modifiziert als Kommunikationsinfrasturkutur genutzt wird. Zudem wurden drei Sicherheitskomponenten erstellt, die von RBW verwaltet werden und die Sicherheit beim Zugriff auf die eingesetzten Anwendungen erhoehen. SDS3 bietet den Anwendungen Sicherheitskontrollfunktionen auf verschiedenen Ebenen, angefangen von einer Strategiekontrolle bis zu anwendungsspezifischen Kontrollfunktionen. Mittels RBW kann die Strategiekontrolle des SDS3 dynamisch durch Reorganisation von Kollabortions-Beziehungen zwischen den Sicherheitskomponenten angepasst werden. <br><br> Neben diesem System wurde der Dynamic Service Composer (DSC) implementiert, welcher auf den Apache Open Source Projekten Apache Axis und WSIF basiert. Im DSC wird RBW eingesetzt, um die Interaktion und Zusammenarbeit von Web Services zu modellieren sowie dynamische Aenderungen der Flussstruktur von Web Services zu ermoeglichen. <br><br> Nach der Implementierung wurden Performance-Tests bezueglich RBW und SDS3 durchgefuehrt. Die Ergebnisse der Tests zeigen, dass eine temporaere Anbindung von Komponenteninstanzen nur einen geringen Einfluss auf die Ausfuehrungseffizienz von Komponeten hat. Ausserdem bestaetigen die Testergebnisse, dass die mit der dynamischen Rekonfiguration verbundene Ausfallzeit extrem niedrig ist.

The constantly growing capacity of reconfigurable devices allows simultaneous execution of complex applications on those devices. The mere diversity of applications deems it impossible to design an interconnection network matching the requirements of every possible application perfectly, leading to suboptimal performance in many cases. However, the architecture of the interconnection network is not the only aspect affecting performance of communication. The resource manager places applications on the device and therefore influences latency between communicating partners and overall network load. Communication protocols affect performance by introducing data and processing overhead putting higher load on the network and increasing resource demand. Approaching communication holistically not only considers the architecture of the interconnect, but communication-aware resource management, communication protocols and resource usage just as well. Incorporation of different parts of a reconfigurable system during design- and runtime and optimizing them with respect to communication demand results in more resource efficient communication. Extensive evaluation shows enhanced performance and flexibility, if communication on reconfigurable devices is regarded in a holistic fashion. / Die Leistungsfähigkeit rekonfigurierbarer Rechensysteme steigt kontinuierlich und ermöglicht damit die parallele Ausführung von immer mehr und immer größeren Anwendungen. Die Vielfalt an Anwendungen macht es allerdings unmöglich ein optimales Kommunikationsnetzwerk zu entwickeln, welches die Anforderung jeder denkbaren Anwendung berücksichtigt. Die Performanz des rekonfigurierbaren Rechensystems sinkt. Das Kommunikationsnetzwerk ist jedoch nicht der einzige Teil des Systems, der Einfluss auf die Kommunikation- sperformanz nimmt. Die Ressourcenverwaltung des Systems beeinflusst durch die Platzierung der Anwendungen die Latenz zwischen Kommunikationspartnern und die Kommunikationslast im Netzwerk. Kommunikationsprotokolle beeinträchtigen die Performanz der Kommunikation durch Daten und Rechen- overhead, die ebenso zu erhöhter Netzwerklast sowie Ressourcenanforderungen führen. In einem ganzheitlichen Kommunikationsansatz wird nicht nur das Kommunikationsnetzwerk berücksichtigt, sondern außerdem Ressourcenverwaltung, Kommunikationsprotokolle und die anderweitige Verwendung vorhandener, temporär ungenutzter Kommunikationsressourcen. Durch Einbeziehung dieser Aspekte während Entwurfs- und Laufzeit und durch Optimierung unter Berücksichtigung der Kommunikationsanforderungen, wird eine ressourceneneffizien tere Kommunikation erreicht. Ausführliche Evaluationen zeigen, dass eine ganzheitliche Betrachtung von Kommunikationsfaktoren, Verbesserungen von Performanz und Flexibilität erzielt.

Le déploiement sensible au contexte et la reconfiguration des applications dans les sessions collaboratives sont les processus permettant de gérer la distribution initiale et ultérieure des outils collaboratifs sur les nSuds des participants en prenant en compte diverses contraintes. Ces contraintes proviennent de la structure de la session, des environnements d'exécution et des relations entre les participants. La majorité des travaux liés au déploiement et à la reconfiguration proposent des solutions qui couvrent essentiellement les deux premiers points mais qui n'accordent pas beaucoup d'importance au dernier point. Ainsi, les applications déployées couvrent les besoins des utilisateurs et sont compatibles avec le contexte local mais l'interopérabilité avec les applications déjà déployées sur les nSuds des voisins n'est pas vérifiée. De plus, le contrôle du déploiement et la découverte des applications requises se fait de façon centralisée et nécessite l'intervention humaine. Nous proposons une approche de déploiement et de reconfiguration automatique basée sur un algorithme décentralisé qui s'exécute sur chaque nSud de déploiement. Cet algorithme utilise des modèles abstraits pour générer des configurations de déploiement valides permettant de respecter les diverses contraintes. Nous avons développé une plate-forme Pair-à-Pair offrant des modules génériques pour supporter cet algorithme. Enfin, nous avons réalisé des prototypes et nous avons mené des tests de performance afin d'évaluer expérimentalement notre approche.

Reproduction de : Habilitation à diriger des recherches : Sciences physiques : Lille 1 : 2004. / N° d'ordre (Lille 1) : 427. Titre provenant de la page de titre du document numérisé. Bibliogr. p. 109-116. Liste des publications et communications.

Diese neu ins Leben gerufene Schriftenreihe widmet sich einer sehr aktuellen Thematik der Technischen Informatik, den eingebetteten, selbstorganisierenden Systemen (ESS). Seit Jahren durchdringen eingebettete Systeme unseren Alltag in fast allen Lebensbereichen. Angefangen von automatisierten Türöffnungssystemen, über komplex gesteuerte Servicemaschinen, z.B. Waschmaschinen, bis hin zu mobilen, persönlich zugeordneten Systemen wie Mobiltelefone und Handheld-Computer sind eingebettete Systeme zu Selbstverständlichkeit geworden. Neue Anforderungen durch den Kunden, der in immer kürzeren Zeitintervallen Neuerungen erwartet und steigende Festkosten für die Einrichtung einer Produktlinie haben einen neuen Aspekt in den Entwurf und Betrieb eingebetteter Systeme gebracht: Selbstorganisation. Einzelaspekte der Selbstorganisation können Selbstdiagnose, Selbsttest, Selbstheilung oder auch statische sowie dynamische Rekonfigurierung von Systemen sein. Dabei sind die Aspekte der Funktionalität und der Kommunikation zu unterscheiden. Beide haben großen Einfluss auf die Performanz und Stabilität eines eingebetteten Systems. Im Bereich der Kommunikation sind die Schnittstellen, die Komponenten des eingebetteten Systems verbinden, von besonderem Interesse. / This newly launched book series addresses a very current subject of computer engineering, embedded selforganising systems (ESS). For years, embedded systems permeate our everyday lives in almost all areas of life. Ranging from automated door opening systems through complex controlled service machines, e.g. Washing machines, to mobile, personally associated systems such as mobile phones and handheld computers, embedded systems have become for granted. New requirements by the customer, who expected changes in shorter time intervals and rising fixed costs of setting up a product line have brought a new aspect in the design and operation of embedded systems: selforganisation. Individual aspects of selforganisation may be self-diagnosis, self-test, self-healing or static as well as dynamic reconfiguration of systems. The aspects of the functionality of communication are distinguished. Both have great influence on the performance and reliability of an embedded system. In the field of the communication interfaces of the embedded system are of particular interest.

Cette thèse porte premièrement sur la reconfiguration dynamique et la simulation hétérogène dans les Réseaux des Capteurs sans Fil. Ces réseaux sont constitués d'une multitude de systèmes électroniques communicants par radio-fréquence, très contraints en énergie. La partie de communication radio entre ces nœuds est la plus consommatrice. C'est pourquoi la minimisation du temps effectif est désirée. On a implémenté une solution qui consiste à envoyer au nœud un fichier de reconfiguration codé utilisant un langage de programmation haut niveau (MinTax). Le nœud sera capable de compiler ce fichier et générer le code object associé à son architecture, in-situ. Grâce au caractère abstrait du MinTax, plusieurs architectures matérielles et systèmes d'exploitation sont visés. Dans un deuxième temps, ce travail de thèse est lié au simulateur de réseaux de capteurs IDEA1TLM.IDEA1TLM permet de prédire quels circuits et configurations sont les plus adéquats à une application sans fil donnée. Ce simulateur a été amélioré pour permettre la simulation rapide des systèmes électroniques matériellement différents dans le même réseau ainsi que le logiciel présent sur les noeuds. Mots clés : Reconfiguration dynamique, Compilation in-situ, MinTax, Hétérogénéité, IDEA1TLM.

Dans ce manuscrit, 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 évènement. 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

Recently, interest in Smart Grid (SG) as a tool for modernization and automation of the current distribution system has rapidly increased. This interest can be explained by the common belief that SG technologies greatly enhance system reliability, power quality and overall efficiency. One of the most important objectives of an SG is to accommodate a wide variety of generation options. This objective aligns with the new trends and policies that encourage higher penetration levels of Distributed Generation (DG) according to environmental, regulatory and economical concerns. Most DG units are either renewable or low emission energy sources, thus meeting the Canadian emission portfolios, while they remain attractive for both utilities and customers for different reasons. DG units can postpone large investment in transmission and central generation, reduce energy losses, and increase system reliability and power quality. SG is centered on several objectives such as self-healing, motivating consumers to participate in grid operation, resisting attacks, accommodating a wide variety of DG units and storage devices, and optimizing assets. Yet, one of the main goals of SG is to increase the reliability of power systems. Reliability is a vital factor in power system performance, due to the full dependence of today???s life on electricity and the high cost of system outages, especially for critical loads. Therefore, one of the main salient features of SG is its ability of self-healing. The insertion of DG units changes distribution networks from being passive with unidirectional power flow and a single power source (the primary substation) towards active networks with multi-directional power flow and several power sources (the primary substation, along with DG units). As a result, the interconnection of DG units creates several impacts on different practices such as voltage profile, power flow, power quality, stability, reliability, fault detection, and restoration. Current policies call for the direct disconnection of all DG units once any failure occurs in the network. However, with a high DG power penetration, the utilities cannot operate the system efficiently without the DG units??? support. Furthermore, automatic disconnection of the DG units during faults reduces the expected benefits associated with DG units drastically. Motivated by the above facts, the overall target of this thesis is to introduce distribution system mechanisms to facilitate realizing the concept of Smart Distribution System (SDS) in both normal and emergency modes. In particular, three main functions are dealt with in this research work: distribution network reconfiguration, DG allocation and self-healing. First, for distribution network reconfiguration, a method based on genetic algorithm is presented to address the reconfiguration problem for distribution systems while the effect of load variation and the stochastic power generation of renewable-based DG units are taken into consideration. The presented method determines the annual distribution network reconfiguration scheme considering switching operation costs in order to minimize annual energy losses by determining the optimal configuration for each season of the year. Second, for DG allocation, a joint optimization algorithm has been proposed to tackle the DG allocation and network reconfiguration problems concurrently, as these two issues are inherently coupled. The two problems are dealt with together while the objectives are minimizing the cost, as an economic issue, and greenhouse gas emissions, as an environmental issue. The proposed method takes the probabilistic nature of both the renewable energy resources and loads into account. The last operation function dealt with in this thesis is distribution system restoration. In order to accomplish this function, two stages are presented: In the first stage, numerous practical aspects related to service restoration problem have been investigated. These aspects include variations in the load and customer priorities, price discounts for in-service customers based on their participation in a load-curtailment scheme that permits other customers to be supplied, the presence of manual and automated switches, and the incorporation of DG units (dispatchable and wind-based units) in the restoration process. In the second stage, the smart grid concept and technologies have been applied to construct a self-healing framework to be applied in smart distribution systems. The proposed multi-agent system is designed to automatically locate and isolate faults, and then decide and implement the switching operations to restore the out-of-service loads. Load variation has been taken into consideration to avoid the need for further reconfigurations during the restoration period. An expert-based decision-making algorithm has been used to govern the control agents. The rules have been extracted from the practical issues related to the service restoration problem, discussed in the first stage.

The ambitious governmental policies, particularly in Europe, in pursuit of established energy targets require an increase in distributed generation. As a result, photovoltaic (PV) technologies have emerged, predominantly at residential Low Voltage (LV) feeders. However, PV rich LV feeders are highly likely to pose technical challenges such as significant voltage rise and thermal overloading. This inevitably limits the volume of PV systems that can be hosted on LV feeders. Therefore, the deployment of solutions that can enable feeders to accommodate greater volumes of PV systems without having any technical issues is crucial. This thesis, consequently, thoroughly investigates one of the potential solutions: transforming the radial operation of LV feeders into ring operation. European-style LV feeders are typically operated in a radial fashion and yet are designed to be reconfigurable with neighbouring feeders. It is, therefore, essential to identify the best pairing option (of PV rich LV feeders) in a practical and straightforward manner due to the large number of existing LV feeders in a given Distribution Network Operator (DNO) area. This thesis proposes a generic innovative methodology to enable DNOs to straightforwardly identify the best pairing feeder; a decision-making tool to facilitate the rapid uptake of PV systems. To accomplish this goal, an impact assessment of a set of real residential LV feeders is carried out to identify the first technical issue/constraint that limits their hosting capacity. Next, regression analyses are carried out to gain an understanding of the relation between this first occurrence of technical issue/constraint and the corresponding level of PV penetration. The most practical and adequately accurate metric needs to be chosen. Feeders are then classified based on the range of metrics to cover all possible pairing cases. Finally, the ring operation of feeders in each class is analysed and hosting capacities are compared to those of radial ones. This process creates a practical matrix from which DNOs can easily identify the best pairing feeders. DNOs are likely to be hesitant to adopt permanent ring operation as it is not typically adopted in traditional LV feeders. Therefore, the switch located between feeders can be operated over time (i.e., dynamic ring operation) to reduce the duration for which ring operation is in place. It is, however, challenging to identify the most favourable control strategy. This thesis proposes different strategies for dynamic ring operation. Note that the most preferable control strategy is that which preserves the benefits of permanent ring operation with the minimum duration of ring operation and minimum number of switching. To achieve this, four different control strategies are explored-using different control cycles and considering hosting capacity, duration and switching. The best control strategy is found to be able to increase hosting capacity as permanent ring operation, reduce switching actions and minimise duration of ring operation compared to other proposed strategies and, crucially, operate ring operation only when it is truly needed. Finally, this thesis investigates the use of ring operation with an LV on-load tap changer (OLTC) as this is recently available voltage control technologies and is increasingly drawing the attention of DNOs. Two approaches are investigated to increase hosting capacity and limit ring operations: the use of the switch and OLTC are controlled separately using local measurements (i.e., localised) and their simultaneous control at the LV transformer level (i.e., centralised). The latter gives the priority to the OLTC to minimise the duration of the ring operation. The assessments are extended to cover an integrated medium and low voltage network to obtain more realistic results. The results show that centralised approach provides better performance considering hosting capacity, the number of switching/tap actions and the duration of ring operation.

Este trabalho apresenta o projeto e arquitetura de uma plataforma para execução de Agentes com funções implementadas em hardware, tomando vantagem do uso de hardware reconfigurável. Os Agentes em hardware são implementados utilizando dispositivos FPGA (Field-programmable Gate Array). O trabalho estende trabalhos anteriores semelhantes na área, com o diferencial de adicionar suporte às funcionalidades de reconfiguração parcial do hardware, suportar aplicações que demandam alto desempenho em hardware – como processamento de sinais e imagens – e redução de recursos de hardware necessários para execução da interface em software. A plataforma proposta utiliza o framework JADE (Java Agent Development Framework), que é um dos frameworks mais populares no estado da arte de desenvolvimento de Agentes e compatível com outros frameworks de Agentes através da conformidade aos padrões FIPA (Foundation for Intelligent Physical Agents). Com o uso do JADE, a plataforma possibilita a comunicação entre Agentes com funções implementadas em hardware e Agentes puramente implementados em software dentro de um mesmo SMA (Sistema Multi-Agente). Uma funcionalidade notável do JADE é a possibilidade de migração de Agentes entre plataformas de um mesmo SMA. Através do uso da reconfiguração parcial de hardware em conjunto com o JADE, a plataforma permite a migração de Agentes de software para hardware e vice-versa, além de suportar reconfiguração de múltiplos Agentes em hardware com um único FPGA. A plataforma faz uso de um único chip através do uso de um processador soft core implementado na lógica programável. O uso deste processador é um diferencial neste trabalho, e mostra que é possível utilizar o JADE em sistemas embarcados com recursos de processamento limitados. Ou seja, em um Agente cuja principal função é implementada em hardware, basta um processador bastante simples para atuar como uma interface entre o hardware e o framework de Agentes. O uso do processador dentro do FPGA tem também o benefício de oferecer formas de acesso mais integrado ao hardware, permitindo maior desempenho na transmissão de dados ao hardware. A plataforma foi validada através de estudos de caso de Agentes com implementações em hardware e em software, incluindo um estudo de caso aplicado de processamento de imagem embarcado utilizando VANTs (Veículos Aéreos Não-Tripulados). O estudo também apresenta comparações de desempenho entre a execução dos Agentes em hardware e em outras plataformas embarcadas de prateleira. Os experimentos realizados mostram um ganho significativo de desempenho nas implementações em FPGA, especialmente considerando processamento de imagens de alta resolução, mesmo considerando que o FPGA executa em frequências consideravelmente reduzidas em comparação às outras plataformas testadas. / This work described the design and architecture of a platform for execution of Agents whose functions are implemented in hardware, by leveraging the use of reconfigurable hardware. The hardware Agents are implemented using FPGA (Field-programmable Gate Array) devices. This work extends previous similar work in this field, while adding the features of hardware partial reconfiguration, supporting applications which require high performance in hardware – such as image or signal processing – and reducing the hardware resource for the software interface execution. The proposed platform makes use of the JADE (Java Agent Development Framework) framework, which is one of the most popular frameworks in state-of-the-art Agent development, and is also compatible with other Agent development frameworks due to compliance with FIPA (Foundation for Intelligent Physical Agents) standards. With the use of JADE, the platform enables communication among Agents which are implemented in hardware and Agents purely implemented in software, inside the same MAS (Multi-Agent System). One notable feature of JADE is the possibility of migrating Agents among platforms inside a single MAS. Through the use of hardware partial reconfiguration along with JADE, the platform enables the migration of Agents from software to hardware and viceversa, in addition to supporting múltiple hardware Agents in a single FPGA. The platform makes use of a single chip, by using a MicroBlaze soft core processor implemented in programmable logic. The use of this processor is a distinction on this work, and it shows that it is possible to use JADE on embedded systems with limited processing power. That is, in an Agent whose main function is implemented in hardware, a very simple processor to act as an interface between hardware and the Agent framework is enough. The use of the soft core processor inside the FPGA also has the benefit of offering more integrated ways of accessing hardware, enabling higher performance for transferring data to hardware. The platform was validated through case studies of hardware and software Agent implementation, including a case study applied to image processing using UAVs (Unmanned Aerial Vehicles). The study also shows performance comparisons between the Agent execution in hardware and in other off-the-shelf embedded platforms. The performed experiments report a significative performance increase in the FPGA implementations, particularly in high resolution image processing, even considering that the FPGA runs in considerably lower clock frequency than the other tested platforms.