http://jasss.soc.surrey.ac.uk Journal of Artificial Societies and Social Simulation: For the exploration and understanding of social processes by means of computer simulation en-GB Copyright Journal of Artificial Societies and Social Simulation 2010-02-01 epress@soc.surrey.ac.uk yearly 4 2010-02-01 http://jasss.soc.surrey.ac.uk/gifs/JASSS-small.jpg http://jasss.soc.surrey.ac.uk martin.neumann@uni-bayreuth.de (Martin Neumann) Article http://jasss.soc.surrey.ac.uk/13/1/12.html Sun, 31 Jan 2010 12:00:00 +0000 Martin Neumann: In this article, principles of architectures relating to normative agents are evaluated with regard to the question whether and to what extend results of empirical research are incorporated in the architecture. In the human sciences, internalisation is a crucial element within the concept of norms. Internalisation distinguishes normative behaviour regulation from mere coercion. The aim of this article is to begin answering the question of to what extent normative agent architectures represent the theoretical construct of norm internalisation. The relevant research in this area may be found in socialisation research in psychology and sociology. Evaluation of conclusions from the empirical sciences allows to identify drawbacks and opportunities in existing architectures, as well as to develop suggestions for future development. ebruch@umich.edu (Elizabeth Bruch) Review http://jasss.soc.surrey.ac.uk/13/1/reviews/bruch.html Sun, 31 Jan 2010 12:00:00 +0000 Review of: Sociology and Complexity Science: A New Field of Inquiry (Understanding Complex Systems) by Castellani, Brian and Hafferty, Frederic William, reviewed by Elizabeth Bruch j.keirstead@imperial.ac.uk (James Keirstead) Review http://jasss.soc.surrey.ac.uk/13/1/reviews/keirstead.html Sun, 31 Jan 2010 12:00:00 +0000 Review of: The Hydrogen Economy: Opportunities and Challenges by Ball, Michael and Wietschel, Martin (eds.), reviewed by James Keirstead stuart.rossiter@eee.strath.ac.uk (Stuart Rossiter, Jason Noble and Keith R.W. Bell) Article http://jasss.soc.surrey.ac.uk/13/1/10.html Sun, 31 Jan 2010 12:00:00 +0000 Stuart Rossiter, Jason Noble and Keith R.W. Bell: Because of features that appear to be inherent in many social systems, modellers face complicated and subjective choices in positioning the scientific contribution of their research. This leads to a diversity of approaches and terminology, making interdisciplinary assessment of models highly problematic. Such modellers ideally need some kind of accessible, interdisciplinary framework to better understand and assess these choices. Existing texts tend either to take a specialised metaphysical approach, or focus on more pragmatic aspects such as the simulation process or descriptive protocols for how to present such research. Without a sufficiently neutral treatment of why a particular set of methods and style of model might be chosen, these choices can become entwined with the ideological and terminological baggage of a particular discipline. This paper attempts to provide such a framework. We begin with an epistemological model, which gives a standardised view on the types of validation available to the modeller, and their impact on scientific value. This is followed by a methodological framework, presented as a taxonomy of the key dimensions over which approaches are ultimately divided. Rather than working top-down from philosophical principles, we characterise the issues as a practitioner would see them. We believe that such a characterisation can be done 'well enough', where 'well enough' represents a common frame of reference for all modellers, which nevertheless respects the essence of the debate's subtleties and can be accepted as such by a majority of 'methodologists'. We conclude by discussing the limitations of such an approach, and potential further work for such a framework to be absorbed into existing, descriptive protocols and general social simulation texts. maltaweel@anl.gov (Mark Altaweel, Lilian N. Alessa and Andrew D. Kliskey) Article http://jasss.soc.surrey.ac.uk/13/1/15.html Sun, 31 Jan 2010 12:00:00 +0000 Mark Altaweel, Lilian N. Alessa and Andrew D. Kliskey: This paper presents a model, using concepts from artificial neural networks, that explains how small rural communities make decisions that affect access to potable freshwater. Field observations indicate that social relationships as well as individual goals and perceptions of decision makers have a strong influence on decisions that are made by community councils. Our work identifies three types of agents, which we designate as alpha, beta, and gamma agents. We address how gamma agents affect decisions made by community councils in passing resolutions that benefit a village's collective access to clean freshwater. The model, which we call the Agent Types Model (ATM), demonstrates the effects of social interactions, corporate influence, and agent-specific factors that determine choices for agents. Data from two different villages in rural Alaska and several parameter sensitivity tests are applied to the model. Results demonstrate that minimizing the social significance and agent-specific factors affecting gamma agents' negative compliance increases the likelihood that communities adopt measures promoting potable freshwater access. The significance of this work demonstrates which types of communities are potentially more socially vulnerable or resilient to social-ecological change affecting water supplies. roth@ehess.fr (Camille Roth) Review http://jasss.soc.surrey.ac.uk/13/1/reviews/roth.html Sun, 31 Jan 2010 12:00:00 +0000 Review of: Connections: An Introduction to the Economics of Networks by Goyal, Sanjeev, reviewed by Camille Roth research@criticalconnections.com.au (Jennifer Badham and Rob Stocker) Article http://jasss.soc.surrey.ac.uk/13/1/11.html Sun, 31 Jan 2010 12:00:00 +0000 Jennifer Badham and Rob Stocker: Social networks generally display a positively skewed degree distribution and higher values for clustering coefficient and degree assortativity than would be expected from the degree sequence. For some types of simulation studies, these properties need to be varied in the artificial networks over which simulations are to be conducted. Various algorithms to generate networks have been described in the literature but their ability to control all three of these network properties is limited. We introduce a spatially constructed algorithm that generates networks with constrained but arbitrary degree distribution, clustering coefficient and assortativity. Both a general approach and specific implementation are presented. The specific implementation is validated and used to generate networks with a constrained but broad range of property values. seppo.sallila@stakes.fi (Seppo Sallila) Article http://jasss.soc.surrey.ac.uk/13/1/1.html Sun, 31 Jan 2010 12:00:00 +0000 Seppo Sallila: In this study, a static microsimulation model SOMA is used to optimize Finland's tax-benefit legislation to alleviate poverty or at least to reduce it significantly. The method is a classical optimization method using a greed optimization strategy. This means an iterative process, where only one poverty diminishing parameter is changed by 10% from its earlier value at each iteration. Expenses are also optimized to reduce inequality as measured by the Gini-coefficient. Revenues and expenses are balanced at every iteration. Certain parameters of social assistance were found to be the most effective in reducing poverty. However by raising substantially the basic unemployment benefit, basic pensions, housing benefits and study grants - leaving social assistance untouched - poverty was reduced by under 50 percent. This means that social assistance is still required to reduce poverty further. Costs are most effectively financed by raising capital income tax. emile@chappin.com (Emile Chappin) Review http://jasss.soc.surrey.ac.uk/13/1/reviews/chappin.html Sun, 31 Jan 2010 12:00:00 +0000 Review of: From System Complexity to Emergent Properties (Understanding Complex Systems) by Aziz-Alaoui, M.A. and Bertelle, C. (eds.), reviewed by Emile Chappin magd@icm.edu.pl (Franciszek Rakowski, Magdalena Gruziel, Michal Krych and Jan P Radomski) Article http://jasss.soc.surrey.ac.uk/13/1/13.html Sun, 31 Jan 2010 12:00:00 +0000 Franciszek Rakowski, Magdalena Gruziel, Michal Krych and Jan P Radomski: In this study we describe a simulation platform used to create a virtual society of Poland, with a particular emphasis on contact patterns arising from daily commuting to schools or workplaces. In order to reproduce the map of contacts, we are using a geo-referenced Agent Based Model. Within this framework, we propose a set of different stochastic algorithms, utilizing available aggregated census data. Based on this model system, we present selected statistical analysis, such as the accessibility of schools or the location of rescue service units. This platform will serve as a base for further large scale epidemiological and transportation simulation studies. However, the first approach to a simple, country-wide transportation model is also presented here. The application scope of the platform extends beyond the simulations of epidemic or transportation, and pertains to any situation where there are no easily available means, other than computer simulations, to conduct large scale investigations of complex population dynamics. bruce@edmonds.name (Bruce Edmonds) Review http://jasss.soc.surrey.ac.uk/13/1/reviews/edmonds.html Sun, 31 Jan 2010 12:00:00 +0000 Review of: Indeterminacy: The Mapped, the Navigable, and the Uncharted by Ciprut, V. Jose (Ed.), reviewed by Bruce Edmonds Nuno.David@iscte.pt (Nuno David, José Castro Caldas and Helder Coelho) Article http://jasss.soc.surrey.ac.uk/13/1/14.html Sun, 31 Jan 2010 12:00:00 +0000 Nuno David, José Castro Caldas and Helder Coelho: [No abstract] floriana.gargiulo@cemagref.fr (Floriana Gargiulo) Review http://jasss.soc.surrey.ac.uk/13/1/reviews/gargiulo.html Sun, 31 Jan 2010 12:00:00 +0000 Review of: Adaptive Networks. Theory, Models and Applications (Understanding Complex Systems) by Gross, Thilo and Sayama, Hiroki (eds.), reviewed by Floriana Gargiulo dphan@msh-paris.fr (Denis Phan and Franck Varenne) Article http://jasss.soc.surrey.ac.uk/13/1/5.html Sun, 31 Jan 2010 12:00:00 +0000 Denis Phan and Franck Varenne: Now that complex Agent-Based Models and computer simulations spread over economics and social sciences - as in most sciences of complex systems -, epistemological puzzles (re)emerge. We introduce new epistemological concepts so as to show to what extent authors are right when they focus on some empirical, instrumental or conceptual significance of their model or simulation. By distinguishing between models and simulations, between types of models, between types of computer simulations and between types of empiricity obtained through a simulation, section 2 gives the possibility to understand more precisely - and then to justify - the diversity of the epistemological positions presented in section 1. Our final claim is that careful attention to the multiplicity of the denotational powers of symbols at stake in complex models and computer simulations is necessary to determine, in each case, their proper epistemic status and credibility. wolfgang.radax@econ.tuwien.ac.at (Wolfgang Radax) Review http://jasss.soc.surrey.ac.uk/13/1/reviews/radax.html Sun, 31 Jan 2010 12:00:00 +0000 Review of: Artificial Economics (Lecture Notes in Economics and Mathematical Systems) by Hernandez, Cesareo, Posada, Marta and Lopez-Paredes, Adolfo (eds.), reviewed by Wolfgang Radax abaker1@swarthmore.edu (Alan Baker) Article http://jasss.soc.surrey.ac.uk/13/1/9.html Sun, 31 Jan 2010 12:00:00 +0000 Alan Baker: One approach to characterizing the elusive notion of emergence is to define that a property is emergent if and only if its presence can be derived but only by simulation. In this paper I investigate the pros and cons of this approach, focusing in particular on whether an appropriately distinct boundary can be drawn between simulation-based and non-simulation-based methods. I also examine the implications of this definition for the epistemological role of emergent properties in prediction and in explanation. jean-philippe.rennard@grenoble-em.com (Jean-Philippe Rennard) Review http://jasss.soc.surrey.ac.uk/13/1/reviews/rennard.html Sun, 31 Jan 2010 12:00:00 +0000 Review of: Allure of Machinic Life: Cybernetics, Artificial Life, and the New AI (Bradford Books) by Johnston, John, reviewed by Jean-Philippe Rennard maaike@cs.uu.nl (Maaike Harbers, John-Jules Meyer and Karel van den Bosch) Article http://jasss.soc.surrey.ac.uk/13/1/4.html Sun, 31 Jan 2010 12:00:00 +0000 Maaike Harbers, John-Jules Meyer and Karel van den Bosch: Several strategies are used to explain emergent interaction patterns in agent-based simulations. A distinction can be made between simulations in which the agents just behave in a reactive way, and simulations involving agents with also pro-active (goal-directed) behavior. Pro-active behavior is more variable and harder to predict than reactive behavior, and therefore it might be harder to explain. However, the approach presented in this paper tries to make advantage of the agents' pro-activeness by using it to explain their behavior. The aggregation of the agents' explanations form a basis for explaining the simulation as a whole. In this paper, an agent model that is able to generate (pro-active) behavior and explanations about that behavior is introduced, and the implementation of the model is discussed. Examples show how the link between behavior generation and explanation in the model can contribute to the explanation of a simulation. aszabo@aitia.ai (Attila Szabo) Review http://jasss.soc.surrey.ac.uk/13/1/reviews/szabo.html Sun, 31 Jan 2010 12:00:00 +0000 Review of: Tax and Benefit Policies in the Enlarged Europe (Public Policy and Social Welfare) by Lelkes, Orsolya and Sutherland, Holly, reviewed by Attila Szabo ahmadreza.asgharpour@gmail.com (Ahmadreza Asgharpour) Review http://jasss.soc.surrey.ac.uk/13/1/reviews/asgharpour.html Sun, 31 Jan 2010 12:00:00 +0000 Review of: Social Structures by Martin, John Levi, reviewed by Ahmadreza Asgharpour dphan@msh-paris.fr (Pierre Livet, Jean-Pierre Muller, Denis Phan and Lena Sanders) Article http://jasss.soc.surrey.ac.uk/13/1/3.html Sun, 31 Jan 2010 12:00:00 +0000 Pierre Livet, Jean-Pierre Muller, Denis Phan and Lena Sanders: Agent-Based Models are useful to describe and understand social, economic and spatial systems' dynamics. But, beside the facilities which this methodology offers, evaluation and comparison of simulation models are sometimes problematic. A rigorous conceptual frame needs to be developed. This is in order to ensure the coherence in the chain linking at the one extreme the scientist's hypotheses about the modeled phenomenon and at the other the structure of rules in the computer program. This also systematizes the model design from the thematician conceptual framework as well. The aim is to reflect upon the role that a well defined ontology, based on the crossing of the philosophical and the computer science insights, can play to solve such questions and help the model building. We analyze different conceptions of ontology, introduce the 'ontological test' and show its usefulness to compare models. Then we focus on the model building and show the place of a systematic ABM ontology. The latter process is situated within a larger framework called the 'knowledge framework' in which not only the ontologies but also the notions of theory, model and empirical data take place. At last the relation between emergence and ontology is discussed. ccioffi@gmu.edu (Claudio Cioffi-Revilla) Article http://jasss.soc.surrey.ac.uk/13/1/7.html Sun, 31 Jan 2010 12:00:00 +0000 Claudio Cioffi-Revilla: Social simulation - an emerging field of computational social science - has progressed from simple toy models to increasingly realistic models of complex social systems, such as agent-based models where heterogeneous agents interact with changing natural or artificial environments. These larger, multidisciplinary projects require a scientific research methodology distinct from, say, simpler social simulations with more limited scope, intentionally minimal complexity, and typically under a single investigator. This paper proposes a methodology for complex social simulations - particularly inter- and multi-disciplinary socio-natural systems with multi-level architecture - based on a succession of models akin to but distinct from the late Imre Lakatos' notion of a 'research programme'. The proposed methodology is illustrated through examples from the Mason-Smithsonian project on agent-based models of the rise and fall of polities in Inner Asia. While the proposed methodology requires further development, so far it has proven valuable for advancing the scientific objectives of the project and avoiding some pitfalls. ciarli@econ.mpg.de (Tommaso Ciarli) Review http://jasss.soc.surrey.ac.uk/13/1/reviews/ciarli.html Sun, 31 Jan 2010 12:00:00 +0000 Review of: Innovation Networks. New Approaches in Modelling and Analyzing by Pyka, Andreas and Scharnhorst, Andrea (eds.), reviewed by Tommaso Ciarli bruce@edmonds.name (Bruce Edmonds) Article http://jasss.soc.surrey.ac.uk/13/1/8.html Sun, 31 Jan 2010 12:00:00 +0000 Bruce Edmonds: There are considerable difficulties in the way of the development of useful and reliable simulation models of social phenomena, including that any simulation necessarily includes many assumptions that are not directly supported by evidence. Despite these difficulties, many still hope to develop quite general models of social phenomena. This paper argues that such hopes are ill-founded, in other words that there will be no short-cut to useful and reliable simulation models. However this paper argues that there is a way forward, that simulation modelling can be used to "boot-strap" useful knowledge about social phenomena. If each bit of simulation work can result in the rejection of some of the possible processes in observed social phenomena, even if this is about a very specific social context, then this can be used as part of a process of gradually refining our knowledge about such processes in the form of simulation models. Such a boot-strapping process will only be possible if simulation models are more carefully judged, that is a greater selective pressure is applied. In particular models which are just an analogy of social processes in computational form should be treated as "personal" rather than "scientific" knowledge. Such analogical models are useful for informing the intuition of its developers and users, but do not help the community of social simulators and social scientists to "boot-strap" reliable social knowledge. However, it is argued that both participatory modelling and evidence-based modelling can play a useful part in this process. Some kinds of simulation model are discussed with respect to their suitability for the boot-strapping of social knowledge. The knowledge that results is likely to be of a more context-specific, conditional and mundane nature than many social scientists hope for. kgt@uni-koblenz.de (Klaus G. Troitzsch) Review http://jasss.soc.surrey.ac.uk/13/1/reviews/troitzsch.html Sun, 31 Jan 2010 12:00:00 +0000 Review of: The Complexity of Human Communication (Hampton Press Communication) by Salem, Philip, reviewed by Klaus G. Troitzsch schutte@icr.gess.ethz.ch (Sebastian Schutte) Article http://jasss.soc.surrey.ac.uk/13/1/2.html Sun, 31 Jan 2010 12:00:00 +0000 Sebastian Schutte: The pioneering works in Agent-Based Modeling (ABM) - notably Schelling (1969) and Epstein and Axtell (1996) - introduced the method for testing hypotheses in "complex thought experiments" (Cederman 1997, 55). Although purely theoretical experiments can be important, the empirical orientation of the social sciences demands that the gap between modeled "thought experiments" and empirical data be as narrow as possible. In an ideal setting, an underlying theory of real-world processes would be tested directly with empirical data, according to commonly accepted technical and methodological standards. A possible procedure for narrowing the gap between theoretical assumptions and empirical data comparison is presented in this paper. It introduces a two-stage process of optimizing a model and then reviewing it critically, both from a quantitative and qualitative point of view. This procedure systematically improves a model's performance until the inherent limitations of the underlying theory become evident. The reference model used for this purpose simulates air traffic movements in the approach area of JFK International Airport in New York. This phenomenon was chosen because it provides a testbed for evaluating an empirical ABM in an application of sufficient complexity. The congruence between model and reality is expressed in simple distance measurements and is visually contrasted in Google Earth. Context knowledge about the driving forces behind controlled approaches and genetic optimization techniques are used to optimize the results within the range of the underlying theory. The repeated evaluation of a model's 'fitness' - defined as the ability to hit a set of empirical data points - serves as a feedback mechanism that corrects its parameter settings. The successful application of this approach is demonstrated and the procedure could be applied to other domains. federico.cecconi@istc.cnr.it (Federico Cecconi, Marco Campenni, Giulia Andrighetto and Rosaria Conte) Article http://jasss.soc.surrey.ac.uk/13/1/6.html Sun, 31 Jan 2010 12:00:00 +0000 Federico Cecconi, Marco Campenni, Giulia Andrighetto and Rosaria Conte: In this work simulation-based and analytical results on the emergence steady states in traffic-like interactions are presented and discussed. The objective of the paper is twofold: i) investigating the role of social conventions in coordination problem situations, and more specifically in congestion games; ii) comparing simulation-based and analytical results to figure out what these methodologies can tell us on the subject matter. Our main issue is that Agent-Based Modelling (ABM) and the Equation-Based Modelling (EBM) are not alternative, but in some circumstances complementary, and suggest some features distinguishing these two ways of modeling that go beyond the practical considerations provided by Parunak H.V.D., Robert Savit and Rick L. Riolo. Our model is based on the interaction of strategies of heterogeneous agents who have to cross a junction. In each junction there are only four inputs, each of which is passable only in the direction of the intersection and can be occupied only by an agent one at a time. The results generated by ABM simulations provide structured data for developing the analytical model through which generalizing the simulation results and make predictions. ABM simulations are artifacts that generate empirical data on the basis of the variables, properties, local rules and critical factors the modeler decides to implement into the model; in this way simulations allow generating controlled data, useful to test the theory and reduce the complexity, while EBM allows to close them, making thus possible to falsify them.