Many who study complex systems believe that the complexity we observe in the world around us is frequently the product of a large number of interactions between components following a simple rule. However, the task of discerning the rule governing the evolution of any given system is often quite difficult, requiring intuition, guesswork, and a great deal of expertise in that domain. To circumvent this issue, researchers have considered the inverse problem where one searches among many candidate rules to reveal those producing interesting behavior. This approach has its own challenges because the search space grows exponentially and interesting behavior is rare and difficult to rigorously define. Therefore, the contribution of this work includes tools and techniques for searching for dimer automaton rules that exhibit self-organization (the transformation of disorder into structure in the absence of centralized control). Dimer automata are simple, discrete, asynchronous rewriting systems that operate over the edges of an arbitrary graph. Specifically, these contributions include a number of novel, surprising, and useful applications of dimer automata, practical methods for measuring self-organization, advanced techniques for searching for dimer automaton rules, and two efficient GPU parallelizations of dimer automata to make searching and simulation more tractable. / Ph. D.

Communication applications have diverse network service requirements. For instance, <em>Voice over IP</em> (VoIP) demands short end-to-end delay, whereas <em>File Transfer Protocol</em> (FTP) benefits more from high throughput than short delay. However, the Internet delivers a uniform best-effort service. As a result, much research has been conducted to enhance the Internet to provide service differentiation. Most of the existing proposals require additional access-control mechanisms, such as admission control and pricing, which are complicated to implement and render these proposals not incrementally deployable. <em>Incentive-compatible Differentiated Scheduling</em> (ICDS) provides incentives for applications to choose a service class according to their burst characteristics without additional access-control mechanisms. <br /><br /> This thesis investigates the behaviour of ICDS with different types of traffic by analysis and extensive simulations. The results show some evidences that ICDS can achieve its design goal. In addition, this thesis revises the initial ICDS algorithm to provide fast convergence for TCP traffic.

Esta pesquisa apresenta um estudo de caso cujo objetivo é descrever os saberes produzidos no processo de auto-organização de grupos de mulheres da Rede Xique-Xique de Comercialização Solidária, nos municípios de Mossoró, Upanema, Governador Dix-Sept Rosado, Baraúna, Grossos, Tibau e Apodi, no estado do Rio Grande do Norte. Trata-se de uma análise sócio histórica e econômica das categorias discursivas de termos como \'mulheres\', \'trabalho, \'família\' e \'história\', assim como da capacidade de transformação social que estes saberes apresentam. A pesquisa de campo foi guiada essencialmente pelo método da observação participante, com procedimentos aplicados pelo método biográfico, mais especificamente pela história de vida. Sobre a coleta dos dados, foram realizadas 11 entrevistas individuais com as mulheres dos grupos auto-organizados; uma entrevista com a coordenadora do CF8 e uma entrevista coletiva, na qual estavam presentes mulheres participantes de seis grupos da região. Além das entrevistas, foram realizadas visitas aos grupos produtivos, participação em reuniões e seminários promovidos pela Rede Xique-Xique ou instituições parceiras. Para analisar todos os dados registrados, as entrevistas foram transcritas e categorizadas. A análise foi realizada a partir do objetivo apresentado e da referenciação das categorias supracitadas, com o auxílio do Software NVivo10. Nesse sentido, foi possível descrever e apreender que o processo de auto-organização dessas mulheres permite a construção de um ato comunicativo entre estas, que por sua vez possibilita a produção de saberes. Esse ato comunicativo torna-se emancipatório na medida em que se caracteriza como uma prática constante de autorreflexão a respeito dos efeitos da organização produtiva autogerida e contribui assim com a transformação de vida dessas mulheres. Sobre a estrutura textual do presente trabalho, a dissertação está dividida em três capítulos. O primeiro capítulo trata da descrição dos aspectos sócio históricos do estado do Rio Grande do Norte e sua relação constitutiva com a ação atual da Rede Xique-Xique. O capítulo dois descreve a estrutura de princípios ou pilares que sustentam a prática da Rede: agroecologia, economia solidária e feminismo. No capítulo três, com base nas categorias discursivas propostas, analiso as histórias de vidas das mulheres entrevistadas durante o trabalho de campo. Por fim, as considerações finais são apresentadas. / This research presents a case study which aims to describe the knowledge produced in the process of self-organizing groups of women Xique-Xique Network Marketing Partnership located in Mossoró, Upanema, Governador Dix-Sept Rosado, Baraúna, Grossos, Tibau e Apodi in the state of Rio Grande do Norte. It is a historical and socioeconomic analysis of the discursive categories of terms such as \'women\', \'work\', \'family\' and \'history\', as well as the ability to social transformation this knowledge presents. The field research was guided essentially by the method of participant observation with procedures applied by the biographical method, more specifically the history of life. On data collection, 11 individual interviews with women of self-organized groups were conducted; interview with the coordinator of the CF8 and a press conference, in which women from six groups in the region were present. Besides the interviews, visits to productive groups, participation in meetings and seminars sponsored by Xique-Xique Network or partner institutions were conducted. To analyze all the recorded data, the interviews were transcribed and using NVivo10, categorized. The analysis was based on the discursive and historical referencing of the above categories. Thus, it was possible to describe and understand that the process of self-organization of these women allows the construction of a communicative act between them, which in turn enables the production of knowledge. This communicative act becomes emancipatory in that it is characterized as a constant practice of self-reflection about the effects of self-managed productive organization and thus contributes to the transformation of these women\'s lives. On the textual structure of the present paper, it is divided into three chapters. The first chapter presents the description of the historical and social aspects of the state of Rio Grande do Norte and its constitutive relationship with the Xique-Xique Network current action. Chapter two describes the structure of principles that support the practice of the group: agroecology, economic solidarity and feminism. In chapter three, based on the discursive categories proposed, I analyze the life histories of the women interviewed during the field work. Finally, the concluding remarks are presented.

A emergência de estruturas espaço-temporais auto-organizadas em sistemas químicos abertos e afastados do estado de equilíbrio termodinâmico resulta da cooperação entre os processos de reação e transporte de espécies ativas e tem se tornado uma área de intensa atividade nos últimos anos. Auto-organização dinâmica na interface sólido/líquido durante a eletrodeposição de Cu-Sn em regime oscilatório é o tema central do presente trabalho. O sistema estudado consistiu da co-eletrodeposição de cobre e estanho sobre eletrodo de ouro policristalino na presença do surfactante Triton X-100. Instabilidades temporais na forma de oscilações de corrente sob controle potenciostático resultantes da presença de uma região de resistência diferencial negativa no perfil voltamétrico têm sido experimentalmente observadas nesse sistema. Acompanhando essas oscilações de corrente há uma deposição intercalada em multicamadas de diferentes composições (basicamente Cu e CuSn), espessuras e morfologias. Especificamente foram estudadas neste trabalho a variedade dinâmica (i.e., o formato e escala de tempo das oscilações de corrente) e a estrutura e composição dos eletrodepósitos formados. Esse estudo tomou como base o mapeamento das regiões de instabilidade no plano (resistência externa, Rext) x (voltagem aplicada, U) sob diferentes concentrações das espécies eletroativas. Curvas de polarização foram obtidas por meio de experimentos quasi-estacionários de varredura catódica a baixas velocidades. De posse do conhecimento da localização das regiões nas quais oscilações de corrente foram observadas, experimentos estacionários foram realizados, e a morfologia e composição dos depósitos foram investigadas ex-situ por meio de microscopia eletrônica de varredura (MEV) e EDX, respectivamente. / The study of the dynamics self-organization on the solid/liquid interface during the co-electro deposition of copper and tin in the presence of adsorbed surfactant was carried out. Temporal instabilities in form of current oscillations under potentiostatic control resulted from the presence of a negative differential resistance in the voltametric profile has been reported in this system. The electro deposits obtained by this oscillatory regimen exhibit layer-by-layer structure with different compositions of Cu-Sn alloys. In the present work current density (j) versus potential(U) curves and j versus time (t) curves were recorded for the co-electro depositions under a series of external resistances (Rext) and polarization potentials. The characterization of the films were carried out by scanning electron microscope (SEM) and energy dispersive x-ray (EDX) analysis. The results confirm that for different values of external resistance and polarization potentials different compositions of the electro deposited Cu-Sn alloys were obtained.

L'Internet des objets est un large sujet qui englobe tous les objets communicants comme les réseaux de capteurs et les systèmes RFID. Ce mémoire résume mes principales contributions dans l'auto-organisation et le passage à l'échelle de la RFID active et passive, plus précisément au travers des intergiciels RFID et des réseaux de capteurs et d'actionneurs sans fil. Cette HDR résume les études et solutions proposées à différents niveaux pour ces différents types de réseaux : auto-organisation, localisation, routage, contrôle de topologie.

In swarm robotics, the control of a group of robots is often fully distributed and does not rely on any leader. In this thesis, we are interested in understanding how to design collective decision making processes in such groups. Our approach consists in taking inspiration from nature, and especially from self organization in social insects, in order to produce effective collective behaviors in robot swarms. We have devised four robotics experiments that allow us to study multiple facets of collective decision making. The problems on which we focus include cooperative transport of objects, robot localization, resource selection, and resource discrimination. We study how information is transferred inside the groups, how collective decisions arise, and through which particular interactions. Important properties of the groups such as scalability, robustness, and adaptivity are also investigated. We show that collective decisions in robot swarms can effectively arise thanks to simple mechanisms of imitation and amplification. We experimentally demonstrate their implementation with direct or indirect information transfer, and with robots that can distinguish the available options partially or not at all.

During the last few years there was a tremendous growth of scientific activities in the fields related to both Physics and Control theory: nonlinear dynamics, micro- and nanotechnologies, self-organization and complexity, etc. New horizons were opened and new exciting applications emerged. Experts with different backgrounds starting to work together need more opportunities for information exchange to improve mutual understanding and cooperation. The Conference "Physics and Control 2007" is the third international conference focusing on the borderland between Physics and Control with emphasis on both theory and applications. With its 2007 address at Potsdam, Germany, the conference is located for the first time outside of Russia. The major goal of the Conference is to bring together researchers from different scientific communities and to gain some general and unified perspectives in the studies of controlled systems in physics, engineering, chemistry, biology and other natural sciences. We hope that the Conference helps experts in control theory to get acquainted with new interesting problems, and helps experts in physics and related fields to know more about ideas and tools from the modern control theory.

Communication applications have diverse network service requirements. For instance, <em>Voice over IP</em> (VoIP) demands short end-to-end delay, whereas <em>File Transfer Protocol</em> (FTP) benefits more from high throughput than short delay. However, the Internet delivers a uniform best-effort service. As a result, much research has been conducted to enhance the Internet to provide service differentiation. Most of the existing proposals require additional access-control mechanisms, such as admission control and pricing, which are complicated to implement and render these proposals not incrementally deployable. <em>Incentive-compatible Differentiated Scheduling</em> (ICDS) provides incentives for applications to choose a service class according to their burst characteristics without additional access-control mechanisms. <br /><br /> This thesis investigates the behaviour of ICDS with different types of traffic by analysis and extensive simulations. The results show some evidences that ICDS can achieve its design goal. In addition, this thesis revises the initial ICDS algorithm to provide fast convergence for TCP traffic.

Das Forschungsfeld Schwarmintelligenz, also die Anwendung des Verhaltens dezentraler selbstorganisierender Tierkollektive, im Kontext der Informatik hat eine Reihe von state-of-the-art Kontroll- und Optimierungsmechanismen hervorgebracht. Die Untersuchung selbstorganisierender biologischer Systeme fördert zum einen das Design neuer robuster und adaptiver Algorithmen. Zum anderen kann sie das Verständnis der Funktionalität von selbstorganisierenden Prinzipien, welche in der Natur auftreten, unterstützen. Diese Arbeit deckt beide zuvor beschriebenen Aspekte ab. Unter Verwendung von Modellen und Simulation werden offene Fragen bezüglich der Organisation und des Verhaltens von sozialen Insekten beleuchtet. Weiter werden Abstraktionen von selbstorganisierenden Konzepten, welche man bei sozialen Insekten findet, genutzt, um neue Methoden zur Optimierung zu entwickeln. Der erste Teil dieser Arbeit untersucht allgemeine Aspekte der Arbeitsteilung sozialer Insekten. Zuerst wird die Anpassungsfähigkeit von unterschiedlich großen Kolonien, bezüglich dynamischer Veränderungen in der Umwelt untersucht. Die Ergebnisse zeigen, dass die Fähigkeit einer Kolonie, auf Veränderung in der Umwelt zu reagieren, von der Koloniegröße beeinflusst wird. Ein weiterer Aspekt der Arbeitsteilung, welcher in dieser Arbeit untersucht wird, ist, inwieweit eine räumliche Verteilung von Aufgaben und Individuen einen Einfluss auf die Arbeitsteilung hat. Die Ergebnisse deuten an, dass soziale Insekten von einer räumlichen Trennung, der zu bewerkstelligenden Aufgaben profitieren, da eine solche Trennung die Produktivität der Kolonie erhöht. Das könnte erklären, warum eine räumliche getrennte Anordnung von Aufgaben und Individuen häufig in realen Kolonien sozialer Insekten beobachtet werden kann. Der zweite Teil dieser Arbeit untersucht verschiedene Aspekte von Selbstorganisation bei Honigbienen. Zunächst wird der Einfluss der räumlichen Verteilung von Nestplätzen auf die Nestplatzsuche der europäischen Honigbiene Apis mellifera untersucht. Die Ergebnisse legen nahe, dass die Nestplatzsuche eines Schwarms aktiv durch die Anordnung der Nestplätze in der Umwelt beeinflusst wird. Eine nestplatzreiche Umgebung kann den Prozess eines Schwarms, sich für einen Nestplatz zu entscheiden, stark behindern. Das könnte erklären, warum Honigbienenarten, die geringe Anforderungen an Nestplätze haben, was die Anzahl von potenziellen Nestplätzen natürlich erhöht, eine sehr ungenaue Form der Nestplatzsuche aufweisen. Ein zweiter Aspekt der Honigbienen, welcher untersucht wird, sind die Steuerungsmechanismen, die dem kollektiven Flug eines Bienenschwarms unterliegen. Zwei mögliche Führungsmechanismen, aktive und passive Führung, werden hinsichtlich ihrer Fähigkeit verglichen, die Flugeigenschaften eines echten Honigbienenschwarms zu reproduzieren. Die Simulationsergebnisse bestätigen aktuelle empirische Befunde und zeigen, dass aktive Führung in der Lage ist, Charakteristika fliegender Schwärme widerzuspiegeln. Bei passiver Führung ist das nicht der Fall. Eine Anwendung biologischer Konzepte im Bereich der Informatik wird anhand der Nestplatzsuche demonstriert. Diese ist ein natürlicher Optimierungsprozess, basierend auf einfachen Regeln. Erzielt wird eine lokale Optimierung, die es einem Schwarm ermöglicht, Nestplätze in einer bisher unbekannten Umgebung zu finden und aus diesen den besten Nestplatz zu wählen. Das ist die Motivation, Nestplatzsuche im Bereich der Optimierung anzuwenden. Hierfür wird zuerst das Optimierungspotenzial der biologischen Nestplatzsuche mit Hilfe eines biologischen Modells untersucht. Basierend auf der Nestplatzsuche wird ein abstrahiertes algorithmisches Schema, das so genannte „Bee Nest-Site Selection Scheme“ (BNSSS) entworfen. Basierend auf dem Schema wird der erste Nestplatzsuche inspirierte Optimierungsalgorithmus „Bee-Nest\\\'\\\' für die Anwendung im Bereich von molekular Docking entwickelt. Im Vergleich zu anderen Optimierungsalgorithmen erzielt „Bee-Nest“ eine sehr gute Leistung. / The application in computer science of the behaviour found in decentralized self-organizing animal collectives -- also known as swarm intelligence -- has brought forward a number of state-of-the art control and optimization mechanisms. Further study of such self-organizing biological systems can foster the design of new robust and adaptive algorithms, as well as aid in the understanding of self-organizing processes found in nature. This thesis covers both of the aspects described above, namely the use of computational models to investigate open questions regarding the organization and behaviour of social insects, as well as using the abstraction of concepts found in social insects to generate new optimization methods. In the first part of this work, general aspects of division of labour in social insects are investigated. First the adaptiveness of different-sized colonies to dynamic changes in the environment is analysed. The findings show that a colony\\\'s ability to react to changes in the environment scales with its size. Another aspect of division of labour which is investigated is the extent to which different spatial distributions of tasks and individuals influence division of labour. The results suggest that social insects can benefit from a spatial separation of tasks within their environment, as this increases the colony\\\'s productivity. This could explain why a spatial organization of tasks and individuals is often observed in real social insect colonies. The second part of this work investigates several aspects of self-organization found in honeybees. First the influence of spatial nest-site distribution on the ability of the European honeybee Apis mellifera to select a new nest-site is studied. The results suggest that a swarm\\\'s habitat can influence its decision-making process. Nest-site rich habitats can obstruct a swarm\\\'s ability to choose a single site if all sites are of equal quality. This could explain why in nature honeybee species which have less requirements regarding a new nest-site have evolved a more imprecise form of nest-site selection than cavity-nesting species. Another aspect of honeybees which is investigated is the guidance behaviour in migrating swarms. Two potential guidance mechanisms, active and passive guidance, are compared regarding their ability to reproduce real honeybee swarm flight characteristics. The simulation results confirm previous empirical findings, as they show that active guidance is able to reflect a number of characteristics which can be observed in real moving honeybee swarms, while this is not the case for passive guidance. Nest-site selection in honeybees can be regarded as a natural optimization process. It is based on simple rules and achieves local optimization as it enables a swarm to decide between several potential nest-sites in a previously unknown dynamic environment. These factors motivate the application of the nest-site selection process to the problem domain of function optimization. First, the optimization potential of the biological nest-site selection process is studied. Then a general algorithmic scheme called ``Bee Nest-Site Selection Scheme\\\'\\\' (BNSSS) is introduced. Based on the scheme the first nest-site inspired optimization algorithm ``Bee-Nest\\\'\\\' is introduced and successfully applied to the domain of molecular docking.

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