Space, the final frontier…

In the fastest ever journal submission to publication I have ever experienced, the following paper has just been published online, and free to grab a copy of:

“Space, the Final Frontier”: How Good are Agent-Based Models at Simulating Individuals and Space in Cities?

It is co-written with Nick Malleson and Andrew Crooks.

Here is the abstract to whet your appetite:

Abstract

Cities are complex systems, comprising of many interacting parts. How we simulate and understand causality in urban systems is continually evolving. Over the last decade the agent-based modeling (ABM) paradigm has provided a new lens for understanding the effects of interactions of individuals and how through such interactions macro structures emerge, both in the social and physical environment of cities. However, such a paradigm has been hindered due to computational power and a lack of large fine scale datasets. Within the last few years we have witnessed a massive increase in computational processing power and storage, combined with the onset of Big Data. Today geographers find themselves in a data rich era. We now have access to a variety of data sources (e.g., social media, mobile phone data, etc.) that tells us how, and when, individuals are using urban spaces. These data raise several questions: can we effectively use them to understand and model cities as complex entities? How well have ABM approaches lent themselves to simulating the dynamics of urban processes? What has been, or will be, the influence of Big Data on increasing our ability to understand and simulate cities? What is the appropriate level of spatial analysis and time frame to model urban phenomena? Within this paper we discuss these questions using several examples of ABM applied to urban geography to begin a dialogue about the utility of ABM for urban modeling. The arguments that the paper raises are applicable across the wider research environment where researchers are considering using this approach.

Question is, what famous line to try and get into the title of a paper next time..?

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ABM and urban economics

New paper just published…

Olner D; Evans A; Heppenstall A (2015) An agent model of urban economics: Digging into emergence, Computers, Environment and Urban Systems, . doi: 10.1016/j.compenvurbsys.2014.12.003

Abstract

Screenshot 2015-10-20 14.09.43This paper presents an agent-based ‘monocentric’ model: assuming only a fixed location for firms, outcomes closely parallel those found in classical urban economic models, but emerge through ‘bottom-up’ interaction in an agent-based model. Agents make buying and movement decisions based on a set of simple costs they face from their current location. These spatial costs are reduced to two types: the costs of moving people and goods across geographical distances and the costs (and benefits) of ‘being here’ (the effects of being at a particular location such as land costs, amenities or disamenities). Two approaches to land cost are compared: landlords and a ‘density cost’ proxy. Emergent equilibrium outcomes are found to depend on the interaction of externalities and time. These findings are produced by looking at how agents react to changing four types of cost, two spatial and two non-spatial: commuting, wage, good cost and good delivery. The models explore equilibrium outcomes, the effect of changing costs and the impact of heterogeneous agents, before focusing in on one example to find the source of emergence in the externalities of agent choice. The paper finishes by emphasising the importance of thinking about emergence as a tool, not an end in itself.