Multi-agent modeling of urban growth distribution in systems of cities

A strong regularity in urban systems has long been identified : the hierarchical distribution of city sizes. Moreover, a closer observation of the evolution of this distribution shows that in the majority of city systems, there is a trend towards a more and more unequal distribution of city sizes. Why does the majority of urban systems show those strong regularities? What are the common growth processes involved? Several dynamic growth models have been proposed but no consensus has yet been reached because of the under-determination of models by those empirical laws. In this presentation we describe a new method of agent-based parsimonious modeling that we think can contribute to the identification of the common urban growth processes. This modeling method is based  on  intensive model exploration for quantitative evaluation of implemented mechanisms. The exploration tools were first developed for the evaluation of SimpopLocal, a model of the organization of urban systems when cities first emerged. The use of those exploration tools was then generalized into a modeling method that was applied for the first time with the construction of the MARIUS family of models which aims at reproducing the evolution of Soviet urbanisation between 1959 and 1989. Those two examples show how this new modeling method can help the construction of urban theories by helping the evaluation of assumptions made on urban processes.

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Communication at the seminar Quanturb, ISC-PIF (Paris), November 19th.

Clara Schmitt and Paul Chapron

Intensive computing for the Social Sciences

Workshop organized around Intensive Computing in Social Sciences at the Complex Systems Institute in Paris, May 21st, from 10:00 am to 5:00 pm, 113 rue Nationale, Paris 13th, France.

Free but necessary registration :


Preliminary Programme

> 10:00-10:30. Introduction : Patrice Bourdelais, Head of INSHS, CNRS

Presentation of the ERC GeoDiverCity : Denise Pumain, UMR Géographie-Cités

Presentation of the Complex Systems Institute : David Chavalarias, UMR CAMS

> 10:30- 11:30. OpenMOLE and its uses in Social Sciences

The OpenMOLE plateform, presentation and tutorial : Romain Reuillon and Mathieu Leclaire, ERC GeoDiverCity / ISC-PIF

A collective and interdisciplininary approach of geographical modeling around OpenMOLE : Paul Chapron, Clémentine Cottineau, Sébastien Rey Coyrehourcq, Clara Schmitt, ERC GeoDiverCity / UMR Géographie-Cités

> 11:30-12:30. Questions and discussion

> 2:00-4:00. “Regards croisés”

Big data and intensive computing : The Social Sciences in revolution ? : David Chavalarias, ISC-PIF

Equipex Matrice : Denis Peschanski, CNRS/Université Paris 1 (to be confirmed)

The “Run My Code” experiment, Christophe Perignon, HEC Paris (to be confirmed)

The MEXICO network : Robert Faivre, INRA

The interdisciplinary MAPS network : Marion Amalric, UMR CITERES

The SimTools network : Patrick Taillandier, UMR Idées

The research group GDR Modys : Xavier Rodier, UMR CITERES

> 4:00-5:00. Discussion : Modeling and intensive computing in Social Sciences

Michel Audiffren (GIS Réseau National des MSH), David Chavalarias (ISC-PIF), Guillaume Deffuant (IRSTEA), Catherine Garbay (IMAG), Michel Gollac (CREST), Thérèse Libourel (LIRMM), Anne Ruas (IFFSTAR), Françoise Thibault (Alliance Athena), Hervé Zwirn (CVT Alliance Athéna)

GeoDiverCity open simulation platform

OpenMOLE has originally been developed in a generic way (and in particular with the cooperation of geographer modelers) to be scientific field independent. That is why dealing with geographical models within the Geodivercity program is straightforward. More specific features for geography will be added during the ERC depending on the needs of the modelers.

A first attempt is to build the Simprocess platform for the multi-level exploration of agent-based models of the Simpop type (PhD by Sébastien Rey-Coyrehourcq).

The next versions will include:

  •   new environments (remote servers through ssh, PBS clusters, cloud),
  •   a standardised serialisation format for workflows,
  •   an integration of cutting edge scientific method for model exploration (optimization, calibration, fitness landscape analysis, sensitivity analysis…),
  •   live visualization based on generic tools,
  •   many other good things!

Romain Reuillon, Mathieu Leclaire, Sébastien Rey-Coyrehourcq, Hélène Mathian, Clara Schmitt and Arnaud Banos

The OpenMOLE software

OpenMOLE (version 0.5) is a piece of software for intensive scientific computing. OpenMOLE is the result of 4 years of daily work with model exploration issues in diverse fields (Human Sciences, Physics, Geography, Food-processing,…). It is 100% FOSS (Free and Open Source Software), 100% written in Scala.

It targets modelers who explore their models at wide scales. It makes it possible to generate automatically wide design of experiments (full-factorial, LHS, Saltelli…) and to take advantage of the computing power of massively parallel execution environments such as computing grids and clusters. It exposes a workflow formalism to design parallel processings in a natural way.

Strengths of OpenMOLE:

  •  a zero-deployment approach: the programs (C, C++, Python, Java, Scala, NetLogo, etc) are embedded at runtime and do not require installing software on execution machines,
  •  a small number of base concepts to handle (4):
    1. tasks (the executable components containing the model for instance);
    2. prototypes (types variables) which are transferred from one task to another;
    3. samplings (how to explore my model?);
    4. environments (where my jobs are executed?);
  •  a modular development for extending the platform with plug-ins in short time and based on OSGi,
  • an optimized and effortless access to grid resources (automatic resource discovery, eager submission, failure handling, management of data transfer …),
  •  a specific task to embed NetLogo models,
  •  a formal workflow validation prior to the execution based on a strongly typed dataflow,
  •  its scalability: it manages  up to hundreds of thousands of task executions from a laptop;
  •  a scripted interface as well as an ergonomic graphical user interface.

Mathieu Leclaire and Romain Reuillon