From modularity to emergence: a primer on the design and science of complex systems

Electrical networks, flocking birds, transportation hubs, weather patterns, commercial organisations, swarming robots... Increasingly, many of the systems that we want to engineer or understand are said to be ‘complex’. These systems are often considered to be intractable because of their unpredictability, non-linearity, interconnectivity, heterarchy and ‘emergence’. Such attributes are often framed as a problem, but can also be exploited to encourage systems to efficiently exhibit intelligent, robust, self-organising behaviours. But what does it mean to describe systems as complex? How do these complex systems differ from the more easily understood ‘modular’ systems that we are familiar with? What are the underlying similarities between different systems, whether modular or complex? Answering these questions is a first step in approaching the design and science of complexity. However, to do so, it is necessary to look beyond the specifics of any particular system or field of study. We need to consider the fundamental nature of systems, looking for a common way to view ostensibly different phenomena. This primer introduces a domain-neutral framework and diagrammatic scheme for characterising the ways in which systems are modular or complex. Rather than seeing modularity and complexity as inherent attributes of systems, we instead see them as ways in which those systems are characterised by those who are interested in them. The framework is not tied to any established mode of representation (e.g. networks, equations, formal modelling languages) nor to any domain-specific terminology (e.g. ‘vertex’, ‘eigenvector’, ‘entropy’). Instead, it consists of basic system constructs and three fundamental attributes of modular system architecture, namely structural encapsulation, function-structure mapping and interfacing. These constructs and attributes encourage more precise descriptions of different aspects of complexity (e.g. emergence, self-organisation, heterarchy). This allows researchers and practitioners from different disciplines to share methods, theories and findings related to the design and study of different systems, even when those systems appear superficially dissimilar

Dealing with abstraction: Case study generalisation as a method for eliciting design patterns

Developing a pattern language is a non-trivial problem. A critical requirement is a method to support pattern writers with abstraction, so as they can produce generalised patterns. In this paper, we address this issue by developing a structured process of generalisation. It is important that this process is initiated through engaging participants in identifying initial patterns, i.e. directly dealing with the 'cold-start' problem. We have found that short case study descriptions provide a productive 'way into' the process for participants. We reflect on a 1-year interdisciplinary pan-European research project involving the development of almost 30 cases and over 150 patterns. We provide example cases, detailing the process by which their associated patterns emerged. This was based on a foundation for generalisation from cases with common attributes. We discuss the merits of this approach and its implications for pattern development

Pareto on the History of Economic Thought as an Aspect of Experimental Economics

The reasons for studying the history of economic thought are diverse. The extreme range of reasons include suggestions that research in this field is: a way of passing time on an intellectual curiosity; an investment in human capital which contributes to a more profound understanding of modern economic theory; an activity of historical interest only, totally devoid of concern with the purely scientific merits of theories; or a subject for sociologists intent on understanding the culture of science and how this has influenced the evolution of scientific knowledge. Interestingly, Pareto had a well developed idea of the scientific reasons for undertaking histories of economic thought, which he saw as an aspect of “experimental economics”. This paper investigates how, and why, Pareto incorporated the history of economic thought as a central element of experimental economics. His approach to the history of economics is shown to be historical, albeit in a limited sense, and non-historical, in the sense that it provided data for the development of experimental hypotheses and theory pertaining to the sociological part of the economic phenomenon.Exegesis, experimental economics, history of economic thought, Pareto

Economics in Relation to Sociology: Dualisms and Vilfredo Pareto's Pluralistic Methodology

Many economists remember the masters of Lausanne for their important contributions to general equilibrium and welfare economics, but Leon Walras and Vilfredo Pareto both pursued much broader social research agendas. Walras did this within the general framework of economics, by complementing his ‘pure economics’ with ‘social economics’. Pareto, in contrast, first isolated economic theory from the influence of other social phenomena and distinguished between the result of theoretical economics and the concrete economic phenomenon. He then developed a general theory of social equilibrium which, inter alia, provided for a synthetic reconciliation of economics with sociology to understand the concrete phenomenon. This paper investigates the relationship between Pareto’s economics and his sociology. Its main contribution is the clarification of the pluralistic character of his methodology. This is done by considering how dualistic distinctions became an important device for Pareto, with particular reference to Sheila Dow’s notion of dualism and Andrew Mearman’s categories of dualism. Pareto’s pluralistic approach is shown as a neo-positive blend of ‘temporary’ Cartesian and non-Cartesian elements, which is not consistent with Dow’s own Babylonian approach to economics. The paper also reveals the economic phenomena that Pareto considered were dominated by sociological influences and, therefore, not amenable to Cartesian analysis.economic equilibrium, pluralism, Vilfredo Pareto, social equilibrium

An Architecture-Centric Approach for Information System Architecture Modeling, Enactement and Evolution

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Regulated MAS: Social Perspective

This chapter addresses the problem of building normative multi-agent systems in terms of regulatory mechanisms. It describes a static conceptual model through which one can specify normative multi-agent systems along with a dynamic model to capture their operation and evolution. The chapter proposes a typology of applications and presents some open problems. In the last section, the authors express their individual views on these mattersMunindar Singh’s effort was partially supported by the U.S. Army Research Office under grant W911NF-08-1-0105. The content of this paper does not necessarily reflect the position or policy of the U.S. Government; no official endorsement should be inferred or implied. Nicoletta Fornara’s effort is supported by the Hasler Foundation project nr. 11115-KG and by the SER project nr. C08.0114 within the COST Action IC0801 Agreement Technologies. Henrique Lopes Cardoso’s effort is supported by Fundação para a Ciência e a Tecnologia (FCT), under project PTDC/EIA-EIA/104420/2008. Pablo Noriega’s effort has been partially supported by the Spanish Ministry of Science and Technology through the Agreement Technologies CONSOLIDER project under contract CSD2007-0022, and the Generalitat of Catalunya grant 2009-SGR-1434.Peer Reviewe