Smart Cities

The Circular Economy

Posted on March 15, 2016 by Michael Batty

The new book from the Ellen MacArthur Foundation contains a series of articles on cities and the built environment that relates to renewability and regeneration in terms of energy, information and new ways of conserving both physical and human resources. I have a chapter here on cities where I examine how we might think about circularity of resources use within the city arguing that we need to generate a renewable infrastructure with respect to how we move between places in the city. To break the non renewable cycle generating ever more urban growth we need to generate a balanced city structure in which our movement patterns are supported and sustained by resources that are self-generated. This probably means a shift from non renewable fuels but ti does not necessarily mean the end of urban growth for it the system is sustainable, then cities can begin to grow in a balanced way. Besides changing our use of energy we may substitute it with information and that probably means autonomous vehicles that use much less energy (but still some) but focus on how best to move using information as a key resource. Anyway what I walk about is rather speculative but it is all part of our new concern for the fact that new urban forms will emerge as we move towards a circylkar economy, with the age-old link between form and functions – which is breaking anyway in the information age – becoming significant in very different ways from the past.

There are lost of other interesting articles in this book and let me list them

Circular business opportunities for the built environment—Ellen Franconi, Brett Bridgeland
The renewable energy transition—Insights from Germany’s Energiewende-Patrick Graichen and Markus Steigenberger
Towards a regenerative food system — Martin Stuchtey and Morten Rossé
Ecosystems as a unifying model for cities and industry— Michael Pawlyn
The circular economy of soil— L. Hunter Lovins
Remanufacturing and the circular economy—Nabil Nasr
Selling access over ownership—Ken Webster
Broader lessons from self-organising traffic lights in city transport systems— Dirk Helbing and Stefan Lämmer
Challenges and capabilities for scaling up circular economy business models—a change management perspective— Markus Zils, Phil Hawkins and Peter Hopkinson
Cities as flows in a circular economy— Michael Batty
Circularity indicators— Chris Tuppen

Posted in city size, Complexity, Emergence, Smart Cities, Urban Dynamics | Leave a comment

Classifying Models: What Krugman Says

Posted on March 13, 2016 by Michael Batty

You may think that this blog has enough on ‘models’ to sink a ship and I have a new editorial on this in EPB. But there is a wonderful article by Paul Krugman on models which I have just come across although written two decades or so ago. Krugman compares evolutionary theory with evolutionary economics in a talk given to the European Association for Evolutionary Political Economy in 1995. The talk is republished here and although it says much on evolution and economics, he has some choice comments about how we should deal with models of the economy (and cities I hesitate to advance). In essence, he says that simulation models must always be interpreted from some meta model, some toy model that abstracts to the point where one really has two models: the full blown simulation and the handy reference – the toy model. He says: “By all means let us use simulation to push out the boundaries of our understanding; but just running a lot of simulations and seeing what happens is a frustrating and finally unproductive exercise unless you can somehow create a “model of the model” that lets you understand what is going on”.

In short he argues that we need models as metaphors and he concludes that: “In short, I believe that economics would be a more productive field if we learned something important from evolutionists: that models are metaphors, and that we should use them, not the other way around”. As all our theories are abstractions, then models represent the way we make these abstractions more practical, more operational. I have had another go at reclassifying models in our urban realm largely because they are continually morphing into new forms and the emphasis is changing, as much because the focus of our interest in cities is changing – witness the growth of the smart cities movement. So you can read the editorial here but Krugman’s essay is really the essential reading.

Posted in Agent-Based Models, Complexity, Interactions, LUTI models, Transport Models, Urban Models | Leave a comment

Variability in Regularity: Transit in Big Cities

Posted on February 24, 2016 by Michael Batty

Chen Zhong is leading CASA’s work in measuring variability and regularity in big data from automated capture of travel demand on subway systems in three world cities. This paper in PLOS One is our first on a comparison of tap in and tap out data in London, Singapore and Beijing where we show how variability is greater in London than Singapore, then Beijing. We argue that this is likely to be due to the much grater crowding on the London than the other systems but also that demand management is less at subway stations than in Singapore and Beijing. Thus the culture of these places and how people travel plays a part. You can get the PDF directly with the online version here

Here is what we say about this work from the paper’s abstract:

“To discover regularities in human mobility is of fundamental importance to our understanding of urban dynamics, and essential to city and transport planning, urban management and policymaking. Previous research has revealed universal regularities at mainly aggregated spatio-temporal scales but when we zoom into finer scales, considerable heterogeneity and diversity is observed instead. The fundamental question we address in this paper is at what scales are the regularities we detect stable, explicable, and sustainable. This paper thus proposes a basic measure of variability to assess the stability of such regularities focusing mainly on changes over a range of temporal scales. We demonstrate this by comparing regularities in the urban mobility patterns in three world cities, namely London, Singapore and Beijing using one-week of smart-card data. The results show that variations in regularity scale as non-linear functions of the temporal resolution, which we measure over a scale from 1 minute to 24 hours thus reflecting the diurnal cycle of human mobility. A particularly dramatic increase in variability occurs up to the temporal scale of about 15 minutes in all three cities and this implies that limits exist when we look forward or backward with respect to making short-term predictions. The degree of regularity varies in fact from city to city with Beijing and Singapore showing higher regularity in comparison to London across all temporal scales. A detailed discussion is provided, which relates the analysis to various characteristics of the three cities. In summary, this work contributes to a deeper understanding of regularities in patterns of transit use from variations in volumes of travellers entering subway stations, it establishes a generic analytical framework for comparative studies using urban mobility data, and it provides key points for the management of variability by policy-makers intent on for making the travel experience more amenable. “