This book lays out a vision for a coherent framework for understanding complex systems. By developing the genuine idea of Brownian agents, the author combines concepts from informatics, such as multiagent systems, with approaches of statistical many-particle physics. It demonstrates that Brownian agent models can be successfully applied in many different contexts, ranging from physicochemical pattern formation to swarming in biological systems.

This open access book, published in the Soft and Biological Matter series, presents an introduction to selected research topics in the broad field of flowing matter, including the dynamics of fluids with a complex internal structure -from nematic fluids to soft glasses- as well as active matter and turbulent phenomena. Flowing matter is a subject at the crossroads between physics, mathematics, chemistry, engineering, biology and earth sciences, and relies on a multidisciplinary approach to describe the emergence of the macroscopic behaviours in a system from the coordinated dynamics of its microscopic constituents. Depending on the microscopic interactions, an assembly of molecules or of mesoscopic particles can flow like a simple Newtonian fluid, deform elastically like a solid or behave in a complex manner. When the internal constituents are active, as for biological entities, one generally observes complex large-scale collective motions. Phenomenology is further complicated by the invariable tendency of fluids to display chaos at the large scales or when stirred strongly enough. This volume presents several research topics that address these phenomena encompassing the traditional micro-, meso-, and macro-scales descriptions, and contributes to our understanding of the fundamentals of flowing matter. This book is the legacy of the COST Action MP1305 “Flowing Matter”.

Recently, there has been an increasing focus on various biological and physical systems known as "active matter". Examples of such systems range from individual units, such as motile cells or artificial self-propelled particles, to large systems of interacting active particles or individuals. The emergence of large-scale collective motion, as exhibited by flocks of birds or bacterial colonies, is just one prominent and fascinating example of self-organization in active matter systems. In this work, we discuss different individual-based models of active matter using the concept of active Brownian motion. The first part of this work explores the dynamical behavior of single active particles with a particular emphasis on the impact of so-called active fluctuations. The second part extends the scope of this study to interacting active Brownian particles and their collective behavior. First, a systematic derivation of kinetic equations for active Brownian particles with velocity alignment is presented. Further on, motivated by recent biological observations, a new type of "escape-pursuit" model of collective motion is introduced and successfully employed in modeling collective locust behavior.

This book constitutes the refereed proceedings of the Workshops which complemented the 11th International Conference on Practical Applications of Agents and Multi-Agent Systems, PAAMS 2013, held in Salamanca, Spain, in May 2013. This volume presents the papers that have been accepted for the workshops: Workshop on Agent-based Approaches for the Transportation Modeling and Optimization, Workshop on Agent-Based Solutions for Manufacturing and Supply Chain, Workshop on User-Centric Technologies and Applications, Workshop on Conflict Resolution in Decision Making, Workshop on Multi-Agent System Based Learning Environments, Workshop on Multi-agent based Applications for Sustainable Energy Systems, Workshop on Agents and multi-agent Systems for AAL and e-Health

Economics and the social sciences are, in fact, the “hard” sciences, as Herbert Simon argued, because the complexity of the problems dealt with cannot simply be reduced to analytically solvable models or decomposed into separate subprocesses. Nevertheless, in recent years, the emerging interdisciplinary “sciences of complexity” have provided new methods and tools for tackling these problems, ranging from complex data analysis to sophisticated computer simulations. In particular, advanced methods developed in the natural sciences have recently also been applied to social and economic problems. The twenty-one chapters of this book reflect this modern development from various modeling perspectives (such as agent-based models, evolutionary game theory, reinforcement learning and neural network techniques, time series analysis, non-equilibrium macroscopic dynamics) and for a broad range of socio-economic applications (market dynamics, technological evolution, spatial dynamics and economic growth, decision processes, and agent societies). They jointly demonstrate a shift of perspective in economics and the social sciences that is allowing a new outlook in this field to emerge. Contents:Market Dynamics:Trading Behavior and Excess Volatility in Toy Markets (M Marsili & D Challet)Percolation Models of Financial Market Dynamics (D Stauffer)Electrodynamical Model of Quasi-Efficient Financial Markets (K N Ilinski & A S Stepanenko)Multi-Agent Market Modeling of Foreign Exchange Rates (G Zimmermann et al.)Forecasting Price Increments Using an Artificial Neural Network (F Castiglione)Spectral Regularization, Data Complexity and Agent Behavior (A Ilyinsky)Technological Evolution:Dynamics of Economic and Technological Search Processes in Complex Adaptive Landscapes (W Ebeling et al.)New Results in a Self-Organized Model of Technological Evolution (A Arenas et al.)Firms' Decision-Making Process in an Evolutionary Model of Industrial Dynamics (W Kwasnicki)Spatial Dynamics and Economic Growth:Modelling Migration and Economic Agglomeration with Active Brownian Particles (F Schweitzer)The Evolution of Industrial Clusters — Simulating Spatial Dynamics (T Brenner & N Weigelt)The Growth Dynamics of German Business Firms (J Voit)A Dynamic Theory of a Firm: An Application of ‘Economic Forces’ (M Estola)Decision Processes:Adaptive Platform Dynamics in Multi-Party Spatial Voting (B M R Stadler)Subtle Nonlinearity in Popular Album Charts (R A Bentley & H D G Maschner)Dynamical Aspects in the Adoption of Agri-Environmental Measures (G Weisbuch & G Boudjema)Collective Choice and Mutual Knowledge Structures (D Richards et al.)Agent Societies:Evolutionary Study of Interethnic Co-Operation (V Kvasnicka & J Pospichal)Coalition Factor in the Evolution of Non-Kin Altruism (J-L Dessalles)Optimal Payoff Functions for Members of Collectives (D H Wolpert & K Tumer)A Day at the Beach: Human Agents Self-Organizing on the Sand Pile (H Ishii et al.) Readership: Researchers in the field of complex system science, economists, sociologists, physicists with an interdisciplinary focus, graduates, and professionals. Keywords:

This book reconciles the existence of technical trading with the Efficient Market Hypothesis. By analyzing a well-known agent-based model, the Santa Fe Institute Artificial Stock Market (SFI-ASM), it finds that when selective forces are weak, financial evolution cannot guarantee that only the fittest trading rules will survive. Its main contribution lies in the application of standard results from population genetics which have widely been neglected in the agent-based community.

This book constitutes the refereed proceedings of the 7th European Conference on Artificial Life, ECAL 2003, held in Dortmund, Germany in September 2003. The 96 revised full papers presented were carefully reviewed and selected from more than 140 submissions. The papers are organized in topical sections on artificial chemistries, self-organization, and self-replication; artificial societies; cellular and neural systems; evolution and development; evolutionary and adaptive dynamics; languages and communication; methodologies and applications; and robotics and autonomous agents.