Monday, January 19, 2009

Generations Model

The Schelling (1971, 1978) model of segregation is probably one of the best known agent-based models and unknowingly, one of the pioneers in the field of Aagent-based modelling (Schelling, 2006). He emphasised the value of starting with rules of behaviour for individuals and using simulation to discover the implications for large scale aggregate outcomes through the interactions of these individuals. This key feature of the model arises because the decisions of any one individual can impact in unexpected and unanticipated ways upon the decisions of others.

While the model is excellent in the sense that it uses of simple logic to illustrate how segregation could emerge, through the mild tastes and preferences to locate amongst like social or economic groups. The model has no population turnover (Fossett and Waren, 2005), households are ‘immortal’ and thus a satisfied household can reside in the same location for ever.

While I been exploring Schellings model (see Crooks, 2008), recently I cam across the "Generations Model" by Hugh Stimson which extends Schellings model so that agents have a chance of of dying and giving birth. But what is interesting about the model is that depending on how many agents of opposite type live nearby, agents may give birth to a new 'mixed' type of agent, who do not share their parent’s biases.

The model is programmed in RepastJ and can be downloaded from here (30kb). More information about the model can be found on Hugh Stimson's blog.


Crooks, A. T. (2008), Constructing and Implementing an Agent-Based Model of Residential Segregation through Vector GIS, Centre for Advanced Spatial Analysis (University College London): Working Paper 133, London, England. (pdf)

Fossett, M. and Waren, W. (2005), Overlooked Implications of Ethnic Preferences for Residential Segregation in Agent-Based Models, Urban Studies, 42(11): 1893-1917.

Schelling, T.C. (1971), Dynamic Models of Segregation, Journal of Mathematical Sociology 1: 143-186.

Schelling, T.C. (1978), Micromotives and Macrobehavior, WW Norton and Company, New York, NY.

Schelling, T.C. (2006), Some Fun, Thirty-Five Years Ago, in Tesfatsion, L. and Judd, K.L. (eds.), Handbook of Computational Economics: Agent-Based Computational Economics, North-Holland Publishing, Amsterdam, Netherlands, pp. 1639-1644.

Wednesday, January 14, 2009

Kvintus Model

Hans Skov-Petersen and his team from the Forest and Landscape Centre at the University of Copenhagen has created the Kvintus model. An agent-based model implemented in Repast and visualised on Google Maps at runtime. Within the model recreationalists (walkers, runners, mountain bikers etc.) can be simulated along with animals (e.g. roe deer). Such a style of model has similarities with the RBSim model (click here to see a previous blog post).

In the YouTube movie below; the yellow squares are joggers (which run at 10 km/h, and prefers marked trails), the circles are Roe deer (the green and blue are deer at various stages in eating and searching for food, red is when they are scared by a jogger, white is when they are searching for a hiding place and black when the deer is hiding.

For more information about the model, readers may be interested in a presentation entitled “Kvintus - an agent-based model of recreational behaviour” on slideshare.

If you like these sorts of models it may be worth reading “Monitoring, simulation and management of visitor landscapes” by Randy Gimblett and Hans Skov-Petersen (eds.). University of Arizona Press. 2008.

Tuesday, January 13, 2009

CASA S4 Modelling Tour Workshop

Last week CASA hosted a two day workshop showcasing our work along with researchers from the University of Leeds as part of the of the S4 European Spatial Analysis network modelling tour. Over 150 people both from the public and private sector came to the event from all across Europe. The first day of the event was designed to showcase CASA's use of new technologies for mapping and visualizing information about cities and was entitled "Geographic Information in a Web-Based World."

Talks ranged from introducing GMapCreator and MapTube which enable web-based mapping for sharing and visualising geographic information, to public engagement via the London Profiler, Public Profiler and the E-Society Classification websites. The geography and ethnicity of people's names was explored which introduced the WorldNames and Onomap websites.

Other talks on the first day explored the use of MapTube and GMapCreator for Crowdsourcing near-real time spatial surveys and understanding crowdsourced geographical information via the analysis of OpenStreetMap. On a more data oriented side, there were talks on exploring urban data collection and mapping, analysing and visualising fine scale urban form and socio-economic datasets. The day concluded with a talk by Andrew Hudson-Smith from Digital Urban on Web 2.0 and neogeography in real and virtual spaces: from geocaching through to Second Life.

The second day of the workshop was entitled "Developments in Urban Models, Simulation and Spatial Analysis" and talks ranged from: rank clocks and scaling in city sizes, geodemographics, retail modelling, the need to capture urban form patterns and processes in agent-based models, pedestrian modelling, consumer behaviour, microsimulation and 3D visualisation and communication of agent-based models.

Click here to see the full program and to download the presentations.

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