La stabilité est un facteur très important dans tous les modes de fonctionnement pour un Système à Puissance Distribué (SPD). En SPD, les charges sont connectées au bus DC à travers d’un filtre entré LC. La plupart des charges de SPD d'avions présents une caractéristique de charge à puissance constante dans un domaine de fonctionnement dans laquelle ils sont étroitement contrôlés. Ainsi, elles peuvent être modélisées comme une résistance négative. Changement de la charge dans un sous-système peut conduire un système stable dans l'instabilité.Une solution pratique pour diminuer le risque d'instabilité est présentée dans cette thèse qui consiste à modifier le contrôle des convertisseurs ou système onduleur-moteur connecté au bus DC. Cette solution permet de stabiliser le système, même avec un condensateur plus petit. Dans la première partie de la thèse, une méthode linéaire est présentée qui permet étudier la stabilité locale d'un système onduleur-moteur connecté au réseau par un filtre LC et un redresseur. Une technique de compensation d’oscillation est utilisée pour améliorer la marge de stabilité du système et la taille de la capacité dc-link sans modifier la structure des boucles de courant ou de couple. Cette technique consiste à superposer une puissance stabilisant sur la puissance absorbée par le drive. Bien que les modèles linéaires puissent être employées avec succès pour décrire le comportement d'un système physique au niveau local, ils échouent souvent de fournir une caractérisation satisfaisante de large-signal. Dans la deuxième partie, deux méthodes pour la stabilisation large-signal du système électrique sont présentées. Dans la dernière partie, une nouvelle méthode, basée sur les spécifications dynamiques est proposée pour étudier la stabilité d'un système électrique en cascade / Stability is the first and very important factor in all modes of operation for a Distributed Power System (DPS). In DPS, loads are connected to the DC-bus through an input LC filter. Most of the loads in DPS of aircraft present a constant power load characteristic within a domain of operation in which they are tightly controlled. So they can be modeled as negative resistance. Change of the load in one subsystem may lead a stable system into instability. A practical solution to decrease the risk of instability presented in this thesis which consists in modifying the control of the converters or inverter-motor drive system connected to the DC-bus. This solution permits to stabilize the system even with a smaller size of capacitor. In the first part of the thesis, a linear method is presented which allows investigating local stability of an inverter-motor-drive system connected to the grid through an LC filter and a rectifier. An oscillation compensation technique is used to improve the stability margin of the system and the size of the dc-link capacitance without modifying structure of the torque or current loops. This technique consists in superposing a stabilizing power on the absorbed power by the drive. Although linear models can be successfully employed to locally describe the behavior of a physical system, they often fail to provide a satisfactory large signal characterization. In the second part, two methods for the large signal stabilization of the electrical system are presented. In the last part, a new method, based on dynamic specifications, is proposed to study the stability of a cascaded electric system

In current design of steel eccentrically braced frames (EBFs), the yielding link is coupled with the floor beam. This often results in oversized link elements, which leads to over-designed structures and foundations. In addition, the beams are expected to sustain significant damage through repeated inelastic deformations under design level earthquakes, and thus the structure may require extensive repair or need to be replaced. These drawbacks can be mitigated by designing EBFs with replaceable shear links. Two different replaceable link types with alternate section profiles, connection configurations, welding details and intermediate stiffener spacing were tested. A total of 13 cyclic quasi-static full-scale cyclic tests were performed, which included tests on eccentrically braced frames with the replaceable shear links, to study their inelastic seismic performance. The links exhibited a very good ductile behaviour, developing stable and repeatable yielding. Additional inelastic rotation capacity can be achieved with bolted replaceable links when allowing bolt bearing deformations to occur. The on-site replaceability of the link sections is confirmed even in the presence of residual deformations of 0.5% drift.

Home networks are evolving vigorously and are also becoming more and more heterogeneous and complex. Home networks contain new services and numerous devices with wired and wireless links. At the same time, users demand high levels of quality of service for many new applications. Hence, the supervision of links quality tends to be mandatory in emergent home networks, to trigger QoS mechanisms. In this context, this dissertation proposes the utilization of the available bandwidth as a performance indicator in hybrid home networks (e.g. for remote service-evaluation, diagnosis and fault detection) and as link-state metric for a number of QoS mechanisms (e.g., admission control, path selection and load balancing). In this dissertation, we firstly explain why available bandwidth probing is a fundamental tool in the new QoS architectures for hybrid home networks and we explore different use cases. We investigate the networking constraints that affect bandwidth probing in hybrid home networks. We explain why most tools to measure available bandwidth on Internet paths are not very efficient on home networks. We make a taxonomic study of a number of state-of-the-art probing techniques and probing tools for available bandwidth. At that aim, we propose a functional framework, called Metrics Profile Capture Filter and Feedback (MPCFF). Based on these studies, we choose Iperf in TCP mode as an attractive tool to estimate available bandwidth. Then, we conduct a performance evaluation on an experimental test bed, to compare Iperf in lightweight TCP-mode vs. various state-of-the-art tools (Wbest, Pathchirp, Pathload and IGI/PTR). We show that Iperf in lightweight TCP mode is superior in terms of accuracy and speed of convergence. Finally, we integrate Iperf in lightweight TCP mode into a path selection protocol using the Inter-MAC software (developed in the Omega European project). We show, on a test bed, how Iperf in lightweight TCP mode enhances the Inter-MAC path selection by eliminating performance deterioration due to time-varying capacity links. Our results show that Iperf in lightweight TCP mode, accurately, triggers path selection and load balancing mechanisms, to adapt the network resources to the strong degradation of WiFi and PLC links. Available bandwidth probing detects and helps to control real-time deviations of the quality of experience, associated of sensitive applications. At the same time, available-bandwidth probing helps the service provider to isolate failures and to monitor the end-to-end residential service, on demand or on long-term periodicity basis.

In current design of steel eccentrically braced frames (EBFs), the yielding link is coupled with the floor beam. This often results in oversized link elements, which leads to over-designed structures and foundations. In addition, the beams are expected to sustain significant damage through repeated inelastic deformations under design level earthquakes, and thus the structure may require extensive repair or need to be replaced. These drawbacks can be mitigated by designing EBFs with replaceable shear links. Two different replaceable link types with alternate section profiles, connection configurations, welding details and intermediate stiffener spacing were tested. A total of 13 cyclic quasi-static full-scale cyclic tests were performed, which included tests on eccentrically braced frames with the replaceable shear links, to study their inelastic seismic performance. The links exhibited a very good ductile behaviour, developing stable and repeatable yielding. Additional inelastic rotation capacity can be achieved with bolted replaceable links when allowing bolt bearing deformations to occur. The on-site replaceability of the link sections is confirmed even in the presence of residual deformations of 0.5% drift.

Data integration aims to combine data of different sources and to provide users with a unified view on these data. This task is as challenging as valuable. In this thesis we propose algorithms for dependency discovery to provide necessary information for data integration. We focus on inclusion dependencies (INDs) in general and a special form named conditional inclusion dependencies (CINDs): (i) INDs enable the discovery of structure in a given schema. (ii) INDs and CINDs support the discovery of cross-references or links between schemas. An IND “A in B” simply states that all values of attribute A are included in the set of values of attribute B. We propose an algorithm that discovers all inclusion dependencies in a relational data source. The challenge of this task is the complexity of testing all attribute pairs and further of comparing all of each attribute pair's values. The complexity of existing approaches depends on the number of attribute pairs, while ours depends only on the number of attributes. Thus, our algorithm enables to profile entirely unknown data sources with large schemas by discovering all INDs. Further, we provide an approach to extract foreign keys from the identified INDs. We extend our IND discovery algorithm to also find three special types of INDs: (i) Composite INDs, such as “AB in CD”, (ii) approximate INDs that allow a certain amount of values of A to be not included in B, and (iii) prefix and suffix INDs that represent special cross-references between schemas. Conditional inclusion dependencies are inclusion dependencies with a limited scope defined by conditions over several attributes. Only the matching part of the instance must adhere the dependency. We generalize the definition of CINDs distinguishing covering and completeness conditions and define quality measures for conditions. We propose efficient algorithms that identify covering and completeness conditions conforming to given quality thresholds. The challenge for this task is twofold: (i) Which (and how many) attributes should be used for the conditions? (ii) Which attribute values should be chosen for the conditions? Previous approaches rely on pre-selected condition attributes or can only discover conditions applying to quality thresholds of 100%. Our approaches were motivated by two application domains: data integration in the life sciences and link discovery for linked open data. We show the efficiency and the benefits of our approaches for use cases in these domains. / Datenintegration hat das Ziel, Daten aus unterschiedlichen Quellen zu kombinieren und Nutzern eine einheitliche Sicht auf diese Daten zur Verfügung zu stellen. Diese Aufgabe ist gleichermaßen anspruchsvoll wie wertvoll. In dieser Dissertation werden Algorithmen zum Erkennen von Datenabhängigkeiten vorgestellt, die notwendige Informationen zur Datenintegration liefern. Der Schwerpunkt dieser Arbeit liegt auf Inklusionsabhängigkeiten (inclusion dependency, IND) im Allgemeinen und auf der speziellen Form der Bedingten Inklusionsabhängigkeiten (conditional inclusion dependency, CIND): (i) INDs ermöglichen das Finden von Strukturen in einem gegebenen Schema. (ii) INDs und CINDs unterstützen das Finden von Referenzen zwischen Datenquellen. Eine IND „A in B“ besagt, dass alle Werte des Attributs A in der Menge der Werte des Attributs B enthalten sind. Diese Arbeit liefert einen Algorithmus, der alle INDs in einer relationalen Datenquelle erkennt. Die Herausforderung dieser Aufgabe liegt in der Komplexität alle Attributpaare zu testen und dabei alle Werte dieser Attributpaare zu vergleichen. Die Komplexität bestehender Ansätze ist abhängig von der Anzahl der Attributpaare während der hier vorgestellte Ansatz lediglich von der Anzahl der Attribute abhängt. Damit ermöglicht der vorgestellte Algorithmus unbekannte Datenquellen mit großen Schemata zu untersuchen. Darüber hinaus wird der Algorithmus erweitert, um drei spezielle Formen von INDs zu finden, und ein Ansatz vorgestellt, der Fremdschlüssel aus den erkannten INDs filtert. Bedingte Inklusionsabhängigkeiten (CINDs) sind Inklusionsabhängigkeiten deren Geltungsbereich durch Bedingungen über bestimmten Attributen beschränkt ist. Nur der zutreffende Teil der Instanz muss der Inklusionsabhängigkeit genügen. Die Definition für CINDs wird in der vorliegenden Arbeit generalisiert durch die Unterscheidung von überdeckenden und vollständigen Bedingungen. Ferner werden Qualitätsmaße für Bedingungen definiert. Es werden effiziente Algorithmen vorgestellt, die überdeckende und vollständige Bedingungen mit gegebenen Qualitätsmaßen auffinden. Dabei erfolgt die Auswahl der verwendeten Attribute und Attributkombinationen sowie der Attributwerte automatisch. Bestehende Ansätze beruhen auf einer Vorauswahl von Attributen für die Bedingungen oder erkennen nur Bedingungen mit Schwellwerten von 100% für die Qualitätsmaße. Die Ansätze der vorliegenden Arbeit wurden durch zwei Anwendungsbereiche motiviert: Datenintegration in den Life Sciences und das Erkennen von Links in Linked Open Data. Die Effizienz und der Nutzen der vorgestellten Ansätze werden anhand von Anwendungsfällen in diesen Bereichen aufgezeigt.

Ein Vorteil von Mathcad^® ist das übersichtliche Arbeitsblatt. Mathematische Gleichungen werden nicht als verwirrende Kette von Buchstaben und Zahlen dargestellt, sondern in eindeutiger mathematischer Notation. Die Gleichungen werden standardmäßig nach der Eingabe auf Plausibilität geprüft. Viele Funktionen - auch komplexe Lösungsalgorithmen - werden bereits mitgeliefert. Weiterhin können formatierte Textfelder für eine gute Dokumentation genutzt werden, z.B. für Berechnungsnachweise. Daher kann das Arbeitsblatt in sehr kurzer Zeit entwickelt werden und ist für neue Anwender leicht nachzuvollziehen. Jedoch wird jeder Vorteil durch einen Nachteil erkauft. So liegen eine geringere Rechengeschwindigkeit, eingeschränkter Codeschutz und nur wenige Möglichkeiten zur Kommunikation mit anderen Programmen vor. Diese Nachteile können durch dynamische Bibliotheken verringert werden. Dieser Artikel stellt die Vorteile der DLL-Programmierung für Mathcad^® dar und zeigt einige Beispiele zur Erhöhung der Rechengeschwindigkeit, zum Quellcodeschutz und zur Codeportierung. / One advantage of Mathcad^® is the well arranged worksheet. Mathematic equations are not displayed in confusing chains of characters but in clear mathematical notation. The equations normaly are checked of plausibility including units after writing. Many functions - even complex solving algorithms - are already defined. Furthermore formatted comments lead to a good documentation, e.g. for calculation reports. Hence the calculation sheets are developed in a very short time and they are easy to comprehend for new users. However every advantage is bought by a disadvantage. Therefore there is a less calculation speed, limited possibilities for code protection and only few possibilities of communication with other programs. These disadvantages can be removed by using dynamic link libraries (DLL's). This article gives an introduction of programming DLL's in Mathcad^® and shows some examples to increase calculation efficiency, code protection and code transfer.

Texte remanié de: Dissertation--Frankfurt-am-Main--Philosophisch-Theologische Hochschule Sankt Georgen, 2007. / Bibliogr. p. 627-663.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The experiment was carried out to evaluate the herbage production, sward structure, stocking rate, weight gain per area and nutritive value of forage as grazed in alexandergrass (Urochloa plantaginea (Link) Hitch) pasture fertilized with nitrogen (N). The experimental design was completely randomized following a repeated measurements arrangement. The treatments were 0; 100; 200 or 300 kg/ha of N. The experimental animals were Angus heifers with initial age and body weight of 15 month and 241.5±5 kg, respectively. The grazing method was continuous stocking with variable number of animals. The N utilization regardless of the amount increases 25% the daily herbage accumulate rate. The N fertilization increases 23% the weight gain per area. The quantity of 97.2 kg/ha of N allows greater leaf mass and increases in 20% the leaf:steam ratio. The alterations in sward structure changes the nutritive value of forage as grazed. The utilization of 112.7 kg/ha of N allows higher stocking rate (2049.8 kg/ha of BW) equivalent to 7.5 heifers per hectare. / Objetivou-se estudar a produção de forragem, estrutura do dossel, taxa de lotação, ganho de peso por área e o valor nutritivo da forragem aparentemente consumida por bezerras de corte em pastagem de papuã (Urochloa plantaginea (Link) Hitch) adubada com nitrogênio (N). O delineamento experimental foi inteiramente casualizado, com medidas repetidas no tempo. Os tratamentos foram 0; 100; 200 ou 300 kg/ha de N. Os animais experimentais foram bezerras da raça Angus com idade e peso iniciais de 15 meses e 241±5 kg, respectivamente. O método de pastejo foi contínuo, com número variável de animais. A utilização de N, independente da quantidade, aumentou em 25% a taxa de acúmulo de forragem. A adubação com N proporciona aumento de 23% no ganho de peso por área. A dose de 97,2 kg/ha de N proporciona maior massa de lâminas foliares e aumento de 20% na razão folha:colmo. As alterações na estrutura do dossel modificam o valor nutritivo da forragem aparentemente colhida pelas bezerras. A dose de 112,7 kg/ha de N permite a manutenção da maior taxa de lotação (2049,8 kg/ha de PC), equivalendo a 7,5 bezerras por hectare.

Les réseaux sociaux occupent une place de plus en plus importante dans notre vie quotidienne et représentent une part considérable des activités sur le web. Ce succès s’explique par la diversité des services/fonctionnalités de chaque site (partage des données souvent multimédias, tagging, blogging, suggestion de contacts, etc.) incitant les utilisateurs à s’inscrire sur différents sites et ainsi à créer plusieurs réseaux sociaux pour diverses raisons (professionnelle, privée, etc.). Cependant, les outils et les sites existants proposent des fonctionnalités limitées pour identifier et organiser les types de relations ne permettant pas de, entre autres, garantir la confidentialité des utilisateurs et fournir un partage plus fin des données. Particulièrement, aucun site actuel ne propose une solution permettant d’identifier automatiquement les types de relations en tenant compte de toutes les données personnelles et/ou celles publiées. Dans cette étude, nous proposons une nouvelle approche permettant d’identifier les types de relations à travers un ou plusieurs réseaux sociaux. Notre approche est basée sur un framework orientéutilisateur qui utilise plusieurs attributs du profil utilisateur (nom, age, adresse, photos, etc.). Pour cela, nous utilisons des règles qui s’appliquent à deux niveaux de granularité : 1) au sein d’un même réseau social pour déterminer les relations sociales (collègues, parents, amis, etc.) en exploitant principalement les caractéristiques des photos et leurs métadonnées, et, 2) à travers différents réseaux sociaux pour déterminer les utilisateurs co-référents (même personne sur plusieurs réseaux sociaux) en étant capable de considérer tous les attributs du profil auxquels des poids sont associés selon le profil de l’utilisateur et le contenu du réseau social. À chaque niveau de granularité, nous appliquons des règles de base et des règles dérivées pour identifier différents types de relations. Nous mettons en avant deux méthodologies distinctes pour générer les règles de base. Pour les relations sociales, les règles de base sont créées à partir d’un jeu de données de photos créées en utilisant le crowdsourcing. Pour les relations de co-référents, en utilisant tous les attributs, les règles de base sont générées à partir des paires de profils ayant des identifiants de mêmes valeurs. Quant aux règles dérivées, nous utilisons une technique de fouille de données qui prend en compte le contexte de chaque utilisateur en identifiant les règles de base fréquemment utilisées. Nous présentons notre prototype, intitulé RelTypeFinder, que nous avons implémenté afin de valider notre approche. Ce prototype permet de découvrir différents types de relations, générer des jeux de données synthétiques, collecter des données du web, et de générer les règles d’extraction. Nous décrivons les expériementations que nous avons menées sur des jeux de données réelles et syntéthiques. Les résultats montrent l’efficacité de notre approche à découvrir les types de relations. / In recent years, social network sites exploded in popularity and become an important part of the online activities on the web. This success is related to the various services/functionalities provided by each site (ranging from media sharing, tagging, blogging, and mainly to online social networking) pushing users to subscribe to several sites and consequently to create several social networks for different purposes and contexts (professional, private, etc.). Nevertheless, current tools and sites provide limited functionalities to organize and identify relationship types within and across social networks which is required in several scenarios such as enforcing users’ privacy, and enhancing targeted social content sharing, etc. Particularly, none of the existing social network sites provides a way to automatically identify relationship types while considering users’ personal information and published data. In this work, we propose a new approach to identify relationship types among users within either a single or several social networks. We provide a user-oriented framework able to consider several features and shared data available in user profiles (e.g., name, age, interests, photos, etc.). This framework is built on a rule-based approach that operates at two levels of granularity: 1) within a single social network to discover social relationships (i.e., colleagues, relatives, friends, etc.) by exploiting mainly photos’ features and their embedded metadata, and 2) across different social networks to discover co-referent relationships (same real-world persons) by considering all profiles’ attributes weighted by the user profile and social network contents. At each level of granularity, we generate a set of basic and derived rules that are both used to discover relationship types. To generate basic rules, we propose two distinct methodologies. On one hand, social relationship basic rules are generated from a photo dataset constructed using crowdsourcing. On the other hand, using all weighted attributes, co-referent relationship basic rules are generated from the available pairs of profiles having the same unique identifier(s) attribute(s) values. To generate the derived rules, we use a mining technique that takes into account the context of users, namely by identifying frequently used valid basic rules for each user. We present here our prototype, called RelTypeFinder, implemented to validate our approach. It allows to discover appropriately different relationship types, generate synthetic datesets, collect web data and photo, and generate mining rules. We also describe here the sets of experiments conducted on real-world and synthetic datasets. The evaluation results demonstrate the efficiency of the proposed relationship discovery approach.

Mit dem Übergang von bauwerksorientierter zu prozessorientierter Arbeitsweise erlangt die domänenübergreifende Bereitstellung von Informationen wachsende Bedeutung. Das betrifft bspw. die Erstellung von Controlling-Kennwerten, die Vorbereitung von Simulationen oder die Betrachtung neuer Aspekte wie Energieeffizienz. Aktuelle Datenformate und Erschließungsmethoden können diese Herausforderung jedoch nicht befriedigend bewältigen. Daher bedarf es einer Methode, welche interdisziplinäre Bauinformationsprozesse uneingeschränkt ermöglicht. Vorhandene Kommunikationsprozesse und Fachanwendungen sollen dabei beibehalten und weitergenutzt werden können. Mit der Multimodell-Methode wird ein Lösungsansatz für die strukturellen Probleme interdisziplinärer Bauinformationsprozesse vorgestellt. Multimodelle bündeln heterogene Fachmodelle unterschiedlicher Domänen und erlauben die Verbindung ihrer Elemente in externen, ID-basierten Linkmodellen. Da die Fachmodelle unberührt bleiben, wird auf diesem Weg eine lose und temporäre Kopplung ermöglicht. Durch den Verzicht auf ein führendes oder integrierendes Datenschema werden keine Transformationsprozesse benötigt, können etablierte und heute übliche Datenformate weitergenutzt und die verlinkten Fachmodelle neutral ausgetauscht werden. Die in Multimodellen verknüpften Daten bieten einen informationellen Mehrwert gegenüber alleinstehenden Fachmodellen. Zusammengehörende Informationen können über die persistenten Links automatisch ausgewertet werden, anstelle manuell vom Menschen immer wieder flüchtig neu zugeordnet werden zu müssen. Somit erscheint ein Multimodell gegenüber einem Benutzer wie ein einziger abgeschlossener Informationsraum. Um solche datenmodell-, datenformat- und domänenübergreifenden Informationsräume komfortabel erstellen und filtern zu können, wird die deklarative Multimodell-Abfragesprache MMQL eingeführt. Diese erlaubt einen generischen Zugriff auf die Originaldaten und bildet die Kernkonzepte der Multimodell-Erschließung - mehrwertige Linkerzeugung und strukturelle Linksemantik - ab. Ein zugehöriger Interpreter ermittelt den Lösungsweg für konkrete Anweisungen und führt diesen auf realen Daten aus. Die Umsetzung und Bereitstellung der Konzepte als IT-Komponenten auf verschiedenen Ebenen - von der Datenstruktur über Bibliotheken und Services bis hin zur alleinstehenden, universellen Multimodell-Software M2A2 - erlaubt die sofortige und direkte Anwendung der Multimodell-Methode in der Praxis. / With the transition of building-oriented to process-oriented work, the provision of cross-domain information gained growing importance - for example in the creation of controlling parameters, the preparation of simulations or when considering new aspects such as energy efficiency. However, current data formats and access methods cannot cope with this challenge satisfactory. Therefore, a method is required, that enables interdisciplinary construction information processes fully. Thereby existing communication processes and domain applications have to be retained and continued to be used as possible. With the multi-model method, an approach to structural problems of such interdisciplinary construction information processes is presented. Multi-models combine heterogeneous models of different domains and allow the connection of their elements in external ID-based link models. As the domain models remain unaffected, a loose and temporary coupling is possible in this way. By not using a leading or integrating data schema, no transformation processes are required, common established data formats can be retained and the linked domain models can be exchanged neutrally. The linked data in multi-models offer an additional value of information over single domain models. Information belonging together can be automatically evaluated by the persistent links - instead of being repeatedly reassigned by people in a volatile way. Thus, a multi-model appears to a user as a single self-contained information space. In order to create and filter such cross-format and cross-domain information spaces comfortably, the declarative multi-model query language MMQL is introduced. It allows for generic access to the original data and integrates the core concepts of the multi-model development - n-ary link generation and structural link semantics. An associated interpreter determines the approach for specific instructions and executes it on real data. The implementation and deployment of the concepts as IT components at various levels - from the data structure via libraries and services, to the universal multi-model software M2A2 - allows an immediate and direct application of the multi-model method in practice.