Archives par mot-clé : Complexity

Urban Dynamics and Simulation Models

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Urban Dynamics and Simulation Models | ERC GeoDiverCityNew book, published by Springer International.

Pumain D., Reuillon R. (eds.), 2017, Urban Dynamics and Simulation Models, Springer, 123p.
DOI 10.1007/978-3-319-46497-8

Authors. Chapron P., Chérel G., Cottineau C., Cura R., Leclaire M., Pumain D., Rey-Coyrehourcq S., Reuillon R., Schmitt C., Swerts E.

Abstract. This monograph presents urban simulation methods that help in better understanding urban dynamics. Over historical times, cities have progressively absorbed a larger part of human population and will concentrate three quarters of humankind before the end of the century. This “urban transition” that has totally transformed the way we inhabit the planet is globally understood in its socio-economic rationales but is less frequently questioned as a spatio-temporal process. However, the cities, because they are intrinsically linked in a game of competition for resources and development, self organize in “systems of cities” where their future becomes more and more interdependent. The high frequency and intensity of interactions between cities explain that urban systems all over the world exhibit large similarities in their hierarchical and functional structure and rather regular dynamics. They are complex systems whose emergence, structure and further evolution are widely governed by the multiple kinds of interaction that link the various actors and institutions investing in cities their efforts, capital, knowledge and intelligence. Simulation models that reconstruct this dynamics may help in better understanding it and exploring future plausible evolutions of urban systems. This would provide better insight about how societies can manage the ecological transition at local, regional and global scales. The author has developed a series of instruments that greatly improve the techniques of validation for such models of social sciences that can be submitted to many applications in a variety of geographical situations. Examples are given for several BRICS countries, Europe and United States. The target audience primarily comprises research experts in the field of urban dynamics, but the book may also be beneficial for graduate students.

Key-words. Simulation, Simulation models, Simpop, Systems of Cities, Complexity, Urban systems, Urban systems dynamics, BRICS.

Link. http://www.springer.com/us/book/9783319464954

Beyond Corroboration: Strengthening Model Validation by Looking for Unexpected Patterns

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diversityNew Paper, in PLoS ONE

Chérel G., Cottineau C., Reuillon R., 2015, « Beyond Corroboration: Strengthening Model Validation by Looking for Unexpected Patterns », PLoS ONE 10(9): e0138212. doi:10.1371/journal.pone.0138212

Abstract. Models of emergent phenomena are designed to provide an explanation to global-scale phenomena from local-scale processes. Model validation is commonly done by verifying that the model is able to reproduce the patterns to be explained. We argue that robust validation must not only be based on corroboration, but also on attempting to falsify the model, i.e. making sure that the model behaves soundly for any reasonable input and parameter values. We propose an open-ended evolutionary method based on Novelty Search to look for the diverse patterns a model can produce. The Pattern Space Exploration method was tested on a model of collective motion and compared to three common a priori sampling experiment designs. The method successfully discovered all known qualitatively different kinds of collective motion, and performed much better than the a priori sampling methods. The method was then applied to a case study of city system dynamics to explore the model’s predicted values of city hierarchisation and population growth. This case study showed that the method can provide insights on potential predictive scenarios as well as falsifiers of the model when the simulated dynamics are highly unrealistic.

Key-words. Simulation and Modelling, Evolutionary Algorithm, Population Growth, Space Exploration, Urbanisation, Complex Systems.

Complex Systems and Geography

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GeoDiverCity Team was active at presenting their work to a diverse and large audience at the inauguration of the Complex Systems Institute in Paris.

Here are some documents we presented :

> A selection of visual results in geographical modeling

[gview file= »http://geodivercity.parisgeo.cnrs.fr/blog/wp-content/uploads/2014/03/GeoModelingok1.pdf »]

Paul Chapron, Clémentine Cottineau, Robin Cura, César Ducruet, Julie Fen-Chong, Sébastien Haule, Marion Le Texier, Nora Marei and Clara Schmitt

Picture Refs : 1. C. Cottineau, 2. D. Holten & J. W. Jarke, 3. R. Cura, 4.5. C. Ducruet, 6. M. Le Texier, 7. C. Cottineau, 8. P. Chapron, 9.10. C. Schmitt

> Netlogo models of systems of cities

  • SimpopNet

Clara Schmitt

 

  • MARIUS : Modeling of Agglomerations of Imperial Russia and the Soviet Union

Clémentine Cottineau and Paul Chapron

 

> A poster about a method to conceive, build and evaluate models at the intersection of generic systems of cities and the specific case of post-Soviet cities

Clémentine Cottineau, Paul Chapron, Denise Pumain and Romain Reuillon

 

> Accessing the European Grid computing power

Mathieu Leclaire and Romain Reuillon

 

ECCS 2013 Satellite meeting

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Urban Systems Modeling: advances from GeoDiverCity and MECHANICITY ERC programmes

Organizing Committee:

Denise Pumain and Arnaud Banos, UMR Géographie-cités and ERG S4 (Spatial Simulation for Social Sciences), CNRS France

pumain@parisgeo.cnrs.fr

arnaud.banos@iscipif.fr

Michael Batty, CASA, University College London, London, UK

m.batty@ucl.ac.uk

Topic:

GeoDiverCity and MECHANICITY are two projects founded by an advanced ERC Grant. Both are about spatial modelling of urban systems with a specific interest in complex systems approaches and are thus within the main area of researches that are of interest for Complex Systems Society and Conference. The GeoDiverCity programme led by Denise Pumain is analysing and modelling the geographical diversity of cities and systems of cities with applications in Europe, USA, Russia, India, China and South Africa. MECHANICITY stands for Morphology, Energy & Climate cHANge In the CITY and is a five year project lead by Mike Batty. It explores ideas about how energy flows tie the components of cities and their morphology together.

Topics covered by this meeting: Urban systems as complex systems, scaling methods, simulation models of urban systems, validation methods for multi-agents models, development of simulation platforms, spatio-temporal modeling of social systems (relevant for tracks 1-fundamentals of complex systems- 3 – infrastructure, planning and environment-  and  6 –social systems-  of ECCS2013 and possibly 2 since of massive use of ICT in model design and testing as well as urban data analysis).

Previous meetings:

This meeting will present advances in research made since the first joint workshop MECHANICITY-GeoDiverCity held in Avignon, April 24th 2012, within the framework of the AGILE Conference (on geomatic and geographical information systems)

Date:

September 19th, 2013

Schedule:

As the workshop is organised by two research teams wanting to compare their experiences, the meeting will at first introduce presentations from each team and is open to a few other selected presentations. Of course the attendance is open and we expect much of the reactions and comments of other specialists in complex system sciences.

From the GeoDiverCity team presentations will be made on use of mobile phone data for urban mobility analysis, urban networks simulation models, new developments of the series of Simpop multi-agents models (SimpopLocal and SimpopNet) as well as the OpenMOLE simulation platform.

From MECHANICITY team presentations will emphasize developments in scaling analysis, spatio-temporal modelling and vizualization tools.

Invited speakers are: Denise Pumain, Arnaud Banos, Clémentine Cottineau,  Clara Schmitt, Sébastien Rey, Elfie Swerts, Romain Reuillon, Mathieu Leclaire, Stefano Ugliano, Michael Batty, Elsa Arcaute, Robin Edwards, Anders Johansson, Sarah Sheppard, Pete Ferguson, Federico Battiston, Melanie Bosredon. Other speakers will be selected according to the available time and the theme of their presentation.

Presentations:

GeoDiverCity

Denise Pumain: Which theoretical bases for understanding the diversity of urban systems?

Clara Schmitt & Sébastien Rey: Simprocess, a method and platform for building geographical simulation models

Romain Reuillon & Mathieu Leclaire: the OpenMOLE simulation platform

Clémentine Cottineau & Paul Chapron: Back in the USSR: a series of models for simulating urban evolution

Elfie Swerts: Complex system view for comparing Indian and Chinese urban systems

Stefano Ugliano: A hypothesis of mutual repulsion for urban networks generated by multinational firms in the food processing sector

Arnaud Banos: title to be confirmed

MECHANICITY

Mike Batty:The New Science of Cities

Elsa Arcaute: Scaling laws and urban hierarchies through percolation theory

Peter Ferguson: Predicting urban activity distributions using new measures of network accessibility

Joan Serras: Testing mobility models: results of the England and Wales case study

Jiaqiu Wang: Using percolation theory to extract street networks of city cores

Roberto Murcio: Urban entropy measures

Evolution and urban modeling: a complexity perspective on the Brazilian city system

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The project performed in this thesis, aiming at the knowledge of the Brazilian system of cities, sets out to demonstrate, within an historical and legal frame, the peculiarities of the history of urbanization in Brazil, a large and populous developing country that is widely considered to have completed an early urban transition.

Undertaking a research on this topics means, primarily, to handle with a problem of an apparent dearth of literature; even if is possible to find many works on Brazilian urbanization, above all in Portuguese language, only a few of these treats urbanization under the aegis of complex systems, as an adaptation process to changes arising from massive urbanization and from insertion in a global, hierarchized network of cities, in which, each metropolitan area is compelled to adapt its internal structure in response to demographic, economic and technical changes. Brazilian main centers will be considered as nodes of a hierarchized structure extending their influence over other agglomerations and territories.

A complexity perspective can provide a general appropriate context within which to understand the behavior of socio-economic systems, notably urban cities systems; computer based models will be associated to a geographical conception in order to analyze urban systems starting with geographical and historical data and trying to foresee their future dynamics through modeling.

By the means of an analysis of both geographical conception and computer-based conception of cities, we will try to set up a model that simulates the peculiarities and so the dynamics of cities and this will be explicitly done using the software Netlogo in order to realize a simulation of a cities system in Brazil. The testing done with our model will be also used to simulate the possible effects of climate changes on the future evolution of urbanization.

Cosmo Antonio Ignazzi

How to explore the future of cities? An evolutionary theory including urban dynamics and territorial history

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Within the framework of the GeoDiverCity programme we are attempting at modelling the future evolution of cities. As cities are very complex systems, any exact prediction is impossible. However, the exploration of plausible futures is possible, with an increasing approximation according to the length of time duration.

The theory behind our modelling is that cities have to be considered not as isolated entities but as interdependent systems being embedded in complex situations summarised by three major aspects:

–       the system of cities with which they have most of their interactions

–       the territory to which they belong

–       the historical period under consideration

Cities are depending on multiple interactions that occur with other cities in multiple networks for all kind of urban activities from local to global scales – that is why we always consider them as part of systems of cities; cities also are rooted in administrative and political territories that generate specific rules and constraints for their development, at local, regional, national and international levels; during the about ten thousands years period of their existence, the type of relations that cities have had with their environment has changed and despite its rather massive common features the urbanisation process has taken a wide range of variations in different parts of the world.

Analysing the evolution of systems of cities from large urban data bases, we suggest recognising that they share many common features but also exhibit a fundamental geo-diversity that is the expression of path dependence in their development. We can model the common dynamics of systems of cities from the interactions between cities, but for understanding and predicting their differentiated evolution we have to take into account their history.  This does not mean building a narrative of successive events but a careful selection of a few specific historical regimes that contextualise the development of systems of cities all over the world (including for instance quality of natural environment, steps of the demographic transition, or relative situation in innovation networks), as well as a restricted set of events that may have more specifically occurred during the history when trying to predict the evolution of any individual city.

Denise Pumain

Pre-AGILE joint workshop MECHANICITY VS GEODIVERCITY (ERC)

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On Tuesday April 24th 2012, the ERC programs MECHANICITY and GEODIVERCITY met at a pre-AGILE workshop in Avignon.

First part: joint session with Workshop “Complexity modelling for urban structure and dynamics” organised by Bin Jiang  and Itzhak Benenson

Mike Batty and Robin Morphet, « Spatial complexity »

Denise Pumain, « Organizing a variety of agent-based models for solving theoretical problems »

Itzhak Benenson, « Equations or geosimulation? To understand the phenomenon you need both! »

Bin Jiang, « Head/tail breaks: A new classification scheme for data with a heavy-tailed distribution »

Second part: MECHANICITY and GEODIVERCITY

Urban Growth, Chair: Denise Pumain

Elsa Arcaute (MECHANICITY), « Looking for scaling in UK Cities »

Clémentine Cottineau (GEODIVERCITY), « A tool for assessing the specificity of the evolutionary path of Russian cities »

 

Urban Boundaries, Chair: Mike Batty

Erez Hatna (MECHANICITY), « Redefining urban boundaries towards scaling »

Elfie Swerts (GEODIVERCITY), « A multi-level analysis of urban growth in the Indian urban system »

Simulating cities, Chair: Arnaud Banos

Mathieu Leclaire and Romain Reuillon (GEODIVERCITY), « Openmole, a generic platform for model experimentation using distributed computing »

Clara Schmitt and Sebastien Rey-Coyrehourcq (GEODIVERCITY), « Simpoplocal, a simulation model for early urban settlements : automated calibration with genetic algorithm »

Erez Hatna (MECHANICITY), « The Schelling model of Segregation: the effect of agents with distributed tolerance thresholds »

Thomas Louail (GEODIVERCITY), « SimpopNano, a model for exploring the effect of networks on urban dynamics »

Conclusion of the day, discussion and perspectives of collaboration