Quantifying the behavior of complex systems arguably presents the common ¡°hard¡±problem across the physical, biological, social, economic sciences. Individual-based or agent-based models have proved useful in a variety of different real world systems: from the physical, biological, medical domains through to social and even financial domains. There are many different models in each of these fields, each with their own particular assumptions, strengths and weaknesses for particular application areas. However, there is a lack of minimal model analysis in which both numerical and analytic results can be obtained, and hence allowing different application domains to be analyzed on a common footing. This thesis focuses on a few simple, yet highly non-trivial, minimal models of a population of interacting objects (so-called agents) featuring internal dynamical grouping. In addition to analyzing these models, I apply them to a number of distinct real world systems. Both the numerical and analytical results suggest that these simple models could be key factors in explaining the overall collective behavior and emergent properties in a wide range of real world complex systems. In particular, I study variants of a particular model (called the EZ model) in order to explain the attrition time in modern conflicts, and the evolution of contagion phenomena in such a dynamically evolving population. I also study and explain the empirical data obtained for online guilds and offline gangs, leading to a team-based model which captures the common quantitative features of the data. I then move on to develop a resource competition model (i.e. the so-called El Farol model) and apply it to the carbon emissions market, mapping the different market factors into model parameters which enable me to explore the potential market behaviors under a variety of scenarios.

Nous assistons aujourd’hui à un développement continu et rapide du Web Structuré, dans lequel les documents (les pages Web) ne sont plus composés que du texte non structuré mais sont centrés sur les données, présentant des contenus structurés et des objets complexes. Ces pages Web sont générées le plus souvent de façon dynamique à partir d’une base de données accessible via des formulaires (Web caché), et sont organisées selon une structure régulière et prédéfinie. Les plates-formes de recherche actuelles ne permettent d’obtenir que des pages en utilisant des méthodes traditionnelles de recherche par des mots-clés, qui sont inadaptées pour interroger le Web structuré. En effet, la recherche par mots-clés est sémantiquement pauvre et ignore les liens structurels existant entre les différents contenus des objets complexes (ex. dans une page Web d’un site commercial, constituée d’une liste de livres, les entités élémentaires “titre” et “auteur” composant chaque “livre” sont présentées selon une disposition qui illustre leurs relations. De nouveaux moyens de recherche sur le Web sont donc nécessaires, pour permettre à l’utilisateur de cibler des données complexes avec une sémantique précise. L’objectif de cette thèse est de fournir des algorithmes efficaces pour l’extraction et la recherche des objets structurées (un livre, un concert de musique, etc.) de façon automatique, à l’aide de méthodes adaptées allant au-delà de la recherche par mots-clés. Nous avons proposé une approche d’interrogation du Web en deux étapes, qui permet à l’utilisateur de décrire le schéma des objets ciblés, de façon souple et précise. Les deux problématiques principales adressées sont : (1) la sélection de sources Web structurées les plus pertinentes pour un schéma fourni par l’utilisateur (c-à-d, contenant les objets, instances de ce schéma), et (2) la construction de wrappers (extracteurs) pour l’extraction des objets complexes ciblés à partir des sources sélectionnées, en exploitant la régularité des structures des pages et la sémantique des données. Notre approche est générique, dans le sens où elle nŠest pas spécifique à des sources ou des objets d’un domaine particulier. Elle a été implantée (système ObjectRunner) et testée sur des sources Web appartenant à des domaines variés. Les résultats obtenus montrent, en particulier, une pertinente élevée au niveau de la sélection de sources et un gain significatif au niveau de la qualité de l’extraction par rapport aux approches existantes. / We are witnessing in recent years a steady growth of the so-called structured Web, in which documents (Web pages) are no longer quasi-textual, but are data-centric, presen-ting structured content, complex objects. Such schematized pages are often generated dynamically by means of formatting templates over a database, possibly using user input via forms (hidden Web). The current Web search platforms allow only to retrieve Web pages by traditional keyword search methods, which are not adapted to query the structured Web. Indeed, keyword search is semantically poor and ignores the existing structural links between various components of complex objects (e.g., in a commercial Web site page, providing book lists, the atomic entities “title” and “author” forming each “book” are displayed in a way that illustrates their relationship. New ways of searching the Web are thus required, in order to enable users to target complex data, with a clear semantics. The main aim of this thesis is to provide effective algorithms for extracting and retrieving structured objects (e.g., a book, a music concert, etc.) automatically, using adapted methods rather going beyond the keyword search ones. We propose a two-phase querying approach of the Web, which allows users to first describe the schema of the targeted objects, in a flexible, lightweight and precise manner. The two main problems we address are : (1) the selection of the most relevant structured Web sources with respect to the schema provided by the user (i.e., containing objects, instances of this schema), and (2) the construction of wrappers for extracting the targeted complex objects from the selected sources, leveraging both the regularity of the pages and the semantics of the data. Our approach is generic, in the sense that it can be applied to any domain and schema for complex objects. It has been implemented in the ObjectRunner system, and tested extensively. The experimental results show high source-selection relevance and significant improvements over existing techniques in terms of extraction precision.

Complex system is a dynamic open system. Through its interactive variables, we can set up a multiple objectives integrative model, using goal programming technique, to help decision makers making decisions more scientifically. With the outcomes forecasted by complex system, decision makers can make strategy more reasonably and precisely. Adoption of Complex system will make strategy management become more scientific and systematic. Non-profit organizations are star industry of 21-th century. How to manage a non-profit organization well and keep it sustainable forever, management science doesn¡¦t develop a system yet. In this research, we take Kaohsiung as a case study to use complex system in managing non-profit organizations. According to complex system-- multiple objectives integrative model in population, economic, social development resource, environment and sanitation, we can make a systematic plan and forecast to help public policy and budget making. The application shows that the model could find a new way for non-profit organization management and provide a connection in theory and practice.

No description available.

This thesis addresses some theoretical issues generated by the results of recent analysis of EEG time series proving the brain dynamics are driven by abrupt changes making them depart from the ordinary Poisson condition. These changes are renewal, unpredictable and non-ergodic. We refer to them as crucial events. How is it possible that this form of randomness be compatible with the generation of waves, for instance alpha waves, whose observation seems to suggest the opposite view the brain is characterized by surprisingly extended coherence? To shed light into this apparently irretrievable contradiction we propose a model based on a generalized form of Langevin equation under the influence of a periodic stimulus. We assume that there exist two different forms of time, a subjective form compatible with Poisson statistical physical and an objective form that is accessible to experimental observation. The transition from the former to the latter form is determined by the brain dynamics interpreted as emerging from the cooperative interaction among many units that, in the absence of cooperation would generate Poisson fluctuations. We call natural time the brain internal time and we make the assumption that in the natural time representation the time evolution of the EEG variable y(t) is determined by a Langevin equation perturbed by a periodic process that in this time representation is hardly distinguishable from an erratic process. We show that the representation of this random process in the experimental time scale is characterized by a surprisingly extended coherence. We show that this model generates a sequence of damped oscillations with a time behavior that is remarkably similar to that derived from the analysis of real EEG's. The main result of this research work is that the existence of crucial events is not incompatible with the alpha wave coherence. In addition to this important result, we find another result that may help our group, or any other research group working on the analysis of brain's dynamics, to prove or to disprove the existence of crucial events. We study the diffusion process generated by fluctuations emerging from the same model after filtering out the alpha coherence, and we study the recursion to the origin. We study the survival probability of this process, namely the probability that up to a given time no re-crossing of the origin occurs. We find that this is an inverse power law with a power that depends on whether or not crucial events exist.

No description available.

This thesis applies an interdisciplinary cybernetic and phenomenological analysis to contemporary theories of representation and interpretation of architecture, resulting in a speculative theoretical model of architectural experience as a behavioural system. The methodological model adopted for this research defines the main structure of the thesis where the narrative and the contributing parts of its complexity emerge. The narrative is presented through objectives and hypotheses that shift and slide between architectural representation and its experience based on three key internal components in architecture: the architectural forms and spaces, the active observers that interact with their environment, and finally, the responsive environment. Three interrelated research questions are considered. The first seeks to define the influence of the theoretical instability between complex life processes, emerging technologies and active perception upon architecture. The second questions the way in which the architectural experience is generated. The third asks: Does architecture behave? And if so, is it possible to define its behavioural characteristics related to its representation, experience and the medium of communication in-between? The thesis begins by exploring the effect of developments in digitally interactive, biological, and hybrid technologies on representation in architecture. An account of architectural examples considers the shift in the meaning of representation in architecture from the actual and literal to the more conceptual and experimental, from the individual human body and its relations to the multifaceted ecosystem of collective and connected cultures. The writings of Kester Rattenbury, Neil Leach, and Peter Cook among others contribute to the transformation of the ordinary perceptual experience of architecture, the development of experimental practices in architectural theory, and the dynamism of our perception. The thesis goes on to suggest that instability in architectural representation does not only depend on the internal components of the architectural system but also on the principles and processes of complex systems as well as changes in active perception and our consciousness that act as the external influences on the system. Established theoretical endeavours in biology of D’Arcy Thompson, Alan Turing, and John Holland and philosophies of Merleau-Ponty, Richard Gregory, and Deleuze and Guattari are discussed in this context. Pre-programmed and computational models, illustrative and generative, are presented throughout the thesis. In the final stage of the development of the thesis architecture is analysed as a system. This is not an unprecedented notion, however defining the main elements and components of this system and their interactions and thereafter identifying that the system behaves and defining its behavioural characteristics, adds to the knowledge in the field of theoretical and experimental architecture. This thesis considers the behavioural characteristics of architecture to be derived from the hypothetical links and unstable thresholds of its non-dualistic notions of materiality and immateriality, reality and virtuality, and finally, intentionality and interpretation.

Dans cette thèse, nous abordons les problèmes de la transmission et du traitement de l'information par les assemblées de neurones, du point de vue de l'approche inter-disciplinaire des systèmes complexes en nous référant principalement aux formalismes de la théorie de l'information et de la théorie des systèmes dynamiques. Dans ce contexte, nous nous focalisons sur les mécanismes de représentation de l'information sensorielle par les activités neuronales à travers le codage neuronal. Nous explorons la structure de ce code, à plusieurs échelles grâce à l'étude de différents signaux électrophysiologiques issus de populations de neurones (signaux unitaires, LFP et EEG). Sur le plan méthodologique, nous avons implémenté différents indices permettant d'extraire objectivement l'information des activités neuronales, mais également d'en caractériser la dynamique sous-jacente à partir de séries temporelles de taille finie (le taux d'entropie). Nous avons également étudié un indicateur peu utilisé (le taux d'information mutuelle), qui permet de quantifier l'auto-organisation et les relations de couplage entre deux systèmes. Grâce à des approches théoriques et numériques, nous analysons les propriétés caractéristiques de ces indices et proposons leur utilisation dans le cadre de l'étude des systèmes neuronaux. Ce travail permet de caractériser la complexité de différentes activités neuronales associées aux dynamiques de transmission de l'information. / In this thesis, we address the problem of transmission and information processing by neuronal assemblies, in terms of the interdisciplinary approach of complex systems by referring mainly to the formalisms of information theory and dynamical systems. In this context, we focus on the mechanisms underlying sensory information representation by neuronal activity through neural coding. We explore the structure of this code under several scales through the study of different neuronal population electrophysiological signals (singel unit, LFP and EEG). We have implemented various indices in order to extract objectively information from neural activity, but also to characterize the underlying dynamics from finite size time series (the entropy rate). We also defined a new indicator (the mutual information rate), which quantifies self-organization and relations of coupling between two systems. Using theoretical and numerical approaches, we analyze some characteristic properties of these indices and propose their use in the context of the study of neural systems. This work allows us to characterize the complexity of different neuronal activity associated to information transmission dynamics.

Avec l’homogénéisation d’un mode de développement à l’image de celui des pays occidentaux les ressources terrestres sont de plus en plus mises à mal rendant de plus en plus urgent un développement durable. Pour atteindre un tel développement, il est nécessaire d’intégrer la dimension environnementale dès les premières étapes du processus de conception de produits. De nombreux outils d’écoconception ont été développés pour satisfaire aux conditions du développement durable. Cependant, ces outils ne sont généralement pas adaptés à la conception de systèmes mécaniques complexes car soit trop spécifiques soit trop généraux ou reposent sur des règles empiriques souvent invérifiables. C'est pourquoi nous proposons dans ce travail de recherche de mettre en place une méthodologie et des outils adaptés à la conception de systèmes complexes. Les travaux effectués nous ont amenés à développer 4 approches méthodologiques permettant à chaque fois d’apporter des réponses aux aspects problématiques identifiés : 1. Les outils d’écoconception actuels sont-ils adaptés à la prise en compte des dimensions multiples de la conception de systèmes ? 2. Comment identifier et hiérarchiser les axes d’amélioration environnemental les plus prometteurs ? 3. Comment déterminer les solutions technologiques adaptées à un système complexe et garantissant la meilleure performance environnementale ? 4. Quelles fonctionnalités pour des performances environnementales optimales pour un système complexe? D’abord, l’approche Pareto/ ACV, introduit dans le chapitre 3, repose sur une simplification du système en considérant que les principales sources d’impact sont générées par une faible partie du système. C’est une approche qui consiste à réaliser une succession d’ACV pour chaque alternative proposée, c’est un processus d’optimisation fastidieux. Toutefois Cette approche fourni des résultats « justes » et est bien adaptée aux raisonnements des concepteurs. En effet par leur expérience du métier et par leur connaissance du produit, le concepteur peut facilement identifier les principaux contributeurs d’impacts. Nous avons, ensuite, développé une approche combinant plans d’expériences et ACV, présentée dans le chapitre 4. Cette approche s’appuie sur une modélisation complète du produit. Le principal apport de la méthode DoE/ ACV est la possibilité de hiérarchiser les paramètres du système en fonction de leur influence sur la performance environnementale du système. Afin de répondre aux limites identifiées lors de l’étude des deux outils précédents nous avons proposé une nouvelle approche basée sur la satisfaction des contraintes (CSP) combinée avec l’ACV et présentée dans le chapitre 5. La phase la plus fastidieuse consiste à modéliser le système (définition des variables de conception, des contraintes du système sous la forme d’équation et des variables de performances que l’on souhaite satisfaire). Il est nécessaire de recueillir des informations sur chaque processus et composants du système, sur la phase d’usage, la maintenance, etc. L’avantage par rapport aux outils précédents est la capacité de l’outil à garantir un ensemble complet de solutions et permet au concepteur de choisir une solution valable selon des variables de performance (amélioration de la performance environnementale selon des indicateurs environnementaux) et contraintes spécifiées lors de la définition du cahier des charges. En complément à l’approche CSP/ ACV, nous avons proposé l’approche EcoCSP, dans le chapitre 6, dans laquelle les spécifications fonctionnelles ne sont plus figées. La méthode ecoCSP permet d’appréhender la configuration de l’architecture produit correspondant à une évolution des performances fonctionnelles. L’approche méthodologique EcoCSP est utilisée pour faire des arbitrages fonctionnels qui modifient l’unité fonctionnelle du système avec les conséquences que cela entraine / The tendency towards a homogenous mode of development modeled on that of Western countries means that sustainable development has become increasingly urgent. In order to implement such development, it is not enough to make superficial reductions of environmental impacts; it is necessary to thoroughly redefine products and their expected performances in such a way that the consequences are compatible with sustainable development. Many ecodesign tools have been developed to meet the requirements of sustainable development. However, these tools are not generally suitable for the design of complex systems because there are either too specific, too general or based on rules of thumb often unverifiable. That is why we propose in this research to develop a methodological approach for ecodesign complex systems. This research work has led us to develop four methodological approaches each time to provide answers to the identified problem areas: 1. Are the current eco-design tools adapted to take into account the multiple dimensions of system design? 2. How to identify and hierarchize the most promising areas of environmental improvement at the early stages of the design process? 3. How to determine technological solutions adapted to a complex system and guarantee the best environmental performance? 4. Which are the necessary features for optimal environmental performances for a complex system? First, the Pareto / LCA approach, introduced in Chapter 3, is based on a simplification of the system considering that the main sources of impact are generated by a small part of it. It consists of a succession of LCA for each proposed alternative; it is a tedious process optimization. However, this approach provides “good” results and is well suited to designers’ reasoning. Indeed by their industry experience and knowledge of the product, the designer can easily identify the main contributors to impacts. Then we developed an approach presented in Chapter 4 that combines Design of Experiment (DoE) and LCA. This approach is based on a complete modeling of the product. The main contribution of the DoE / ACV approach is the ability to prioritize the system parameters according to their influence on the environmental performance of the system. To address the limitations identified in the study of the two previous tools we have proposed a new methodological approach based on Constraint Satisfaction Problem (CSP) combined with LCA and presented in Chapter 5. The most time consuming step is to model the system (definition of design parameters, constraints, equation and performance). It is necessary to gather information about each process and system components, the use phase, maintenance, etc. The advantage over previous tools is the ability of the approach to ensure a complete set of solutions, allowing the designer to choose a good one that complies to environmental performance and constraints specified in the definition specifications. In addition to the CSP / LCA approach, we propose an EcoCSP approach, in Chapter 6. In it, the functional specifications are no longer “frozen”. The approach EcoCSP allows us to understand the configuration of the product corresponding to a change in functional performance. The EcoCSP is used to make functional trade-offs that affect the functional unit of the system with the consequences this entails.

A histórica desconsideração da variável ambiental dentro da concepção teórica e dos modelos de crescimento econômico revela um posicionamento ideológico muito claro: a resistência na aceitação do ambiente como fator limitante ou mesmo como elemento estratégico do ponto de vista da riqueza de uma nação ou região. Para além das questões mais frequentemente debatidas, que associam os elementos do ambiente a meros insumos necessários aos processos produtivos, a consideração de conceitos não usuais no arcabouço teórico da economia tradicional, como serviços ecossistêmicos, resiliência, entropia e histerese, teria condições de ampliar e relativizar a interpretação de uma série de premissas e dogmas da ciência econômica tradicional. O conceito de capital natural, neste sentido, apresenta-se como fundamental e estratégico, uma vez que permite acomodar toda a complexidade inerente à dimensão ambiental e relacioná-la com o sistema socioeconômico, adequando e balizando o enquadramento da questão da sustentabilidade. Ainda, o presente trabalho parte da definição fundamentada de que ambos os sistemas - econômico e ambiental - são essencialmente complexos e, que os efeitos das relações entre os mesmos não são triviais e possuem altos níveis de incerteza associados à sua dinâmica. Dentro dessa orientação, o trabalho se propôs a realizar uma reflexão sobre a sustentabilidade sob a ótica dos sistemas complexos, por meio de uma revisão bibliográfica crítica e de um exercício de modelagem baseada em agentes para a simulação do crescimento econômico considerando a variável ambiental. As análises realizadas indicam que a incorporação de novos conceitos oriundos dos sistemas complexos poderiam estabelecer um novo suporte para a análise de políticas macroeconômicas de crescimento, da sustentabilidade e, em última instância, contribuir com o fortalecimento de premissas básicas da economia ecológica. / The historical disregard of the environmental issue in the theoretical conception and the economic growth models reveals a clear ideological positioning: the resistance to accept the environment as a limiting factor or as a strategic element from the point of view of nations or regions wealth. Beyond the frequently debated questions, that associate the environmental elements to simple inputs that are necessary to productive processes, the consideration of the non-usual concepts of the traditional economic theory, like ecosystem services, resilience, entropy and hysteresis, would give better conditions to expand and relativize the interpretation of a series of premises and traditional economy dogmas. The natural capital concept, in this sense, represents itself as an essential and strategic concept, since it permits to accommodate all the complexity inherent to the environmental dimension and associate it to the economic system, fitting and marking out the sustainability framework. Still, the present work starts from the definition that both of the systems environmental and economic are essentially complex and that the effects of the relations between them are not trivial and have high levels of uncertainty associated to its dynamic. Whitin this orientation, this work proposed to realize a reflection about sustainability under the complex systems perspective, through a critical literature review and a multi-agent based modeling exercise, to simulate economic growth considering the environmental dimension. This analyses indicated that the incorporation of new concepts, from the complex systems theory, could establish a new support for the macroeconomic policies analysis, as well for the sustainability policies and, ultimately, to contribute to the strengthening of the basic ecological economy premises.