Entropy

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Entropy Models (Alan Wilson, 1970-2011) take as their hypothesis that Boltzmann’s theory of entropy as microcanonical ensemble can be used to model human mobility in urban travel models. In use since 1970 as travel demand models, Wilson’s entropy models have evolved into BLV models which use Lotka-Volterra dynamics to model the evolution of urban space.

In this particular example we see a regional retail model which models both the fast-scale urban travel demand resulting from retail activity, along with the slow-scale evolution of retail space as retail centers grow and diminish. The video depicts the navigation of model outcomes in a grid that represents a parameter surface.

BLV models are part of a shift towards modeling cities as complex systems, providing a probabilistic basis (statistical physics) for determining the state of an urban model under constraints. The complexity paradigm forces planners to accept that multiple equilibria mean a range of possible outcomes can result from even the smallest planning interventions.

See Also: Bifurcation, The Living City, Fractal