Critical mass: When does a crowd become dangerous

There was an interesting article in the UKs' The Guardian a few months ago entitled "Critical mass: When does a packed but happy crowd become a dangerous, even lethal one?" which discusses as the title suggests when does a crowd become dangerous? The article starts with an incident in occurring at a Walmart's store in the US on Black Friday in 2008 where a crowd rushed into a store searching for bargains and a security guard died in the rush.

The reason I am blogging about it is that the paper sums up quite nicely and in understandable way the use of pedestrian modeling to understand such events and ways to potentially mitigate such occurrences from happening again.

One line I like is this that "in the almost weekly occurrence, somewhere in the world, of someone being injured or killed in a crowd." Other incidents for example, include the opening of the Primark flagship store in London in 2007 (below) or Jamarat bridge incident, where in 2004 more than 250 people were killed during a ritual part of the hajj known as the "stoning of the devil".

Shoppers at the opening of Primark in London tussle to get into the store (see the article).

Muslim pilgrims walk over a Jamarat bridge during the 'Jamarat' ritual, in Mina near Mecca.

The full article can be found here.

AAG SPECIAL SESSION: Modeling Geographic Complexity

For those interested we are organizing a special session(s) at the forthcoming AAG in Washington DC. See below for details:

LOCATION AND DATES:
Association of American Geographers Annual Meeting
April 14-18, 2010, Washington, DC, USA

SPONSORS:
Spatial Analysis and Modeling, Geographic Information Systems and Science, Human Dimensions of Global Change Specialty Groups of the AAG and the Geographical Information Science Group of the Royal Geographical Society.

DESCRIPTION:

Understanding geographical systems represents one of the greatest challenges of our time. Complexity has emerged as a useful paradigm to effectively study linked human, socioeconomic and biophysical systems at a variety of different spatial and temporal scales. As a result, descriptive and predictive models of various levels of sophistication and using mostly agents, genetic algorithms, cellular automata and neural networks are now beginning to regularly appear in the geographic literature. However, there still remains many unresolved conceptual, technical and application challenges associated with these complexity based models. The goal of this session is to focus on the following themes:

1. Conceptual: shared and unique complexity signatures in geographic systems; existing and emerging geographical and complexity theories; epistemological and ontological influences; complexity based model designs; networks and hybrid models; linking classical and spatial statistics in complexity studies.
2. Technical: space-time patterns and dynamics; standardizing the development and representation of complex systems; rule selection and implementation; multiple-scale interactions and structure, system evolution and self-organization; learning and adaptation; calibration, validation and verification; path-dependence; non-linearity.
3. Applications: effectiveness of complexity models when embedded in political, institutional and socio-economic systems; human-environment interactions; earth systems science; land use science; landscape ecology; sustainability analysis.

In order to widely disseminate the ideas emerging from this session, the organizers of the session are exploring the possibility for a special issue of a journal and /or an edited book so that authors will have the opportunity to suitably revise their presentations for publication. Priority will be given for work that has not been published, in review or in press.

Please e-mail the abstract and key words with your expression of intent to Andrew Crooks by October 19th, 2009. Please make sure that your abstract conforms to the AAG guidelines in relation to title, word limit and key words and as specified at <http://www.aag.org/annualmeetings/2010/papers.htm#instructions>. An abstract should be no more than 250 words that describes the presentation's purpose, methods, and conclusions as well as to include keywords. Full submissions will be given priority over submissions with just a paper title.

ORGANIZERS:

Arika Ligmann-Zielinska, Michigan State University <ligmannz@msu.edu>
Andrew Crooks, George Mason University <acrooks2@gmu.edu>
Alison Heppenstall, University of Leeds <A.J.Heppenstall@leeds.ac.uk>
Moira Zellner, University of Illinois at Chicago <mzellner@uic.edu>
Suzana Dragicevic, Simon Fraser University <suzanad@sfu.ca>,

TIMELINE:
September 3nd, 2009: Call for papers.

October 19th, 2009: Abstract submission and expression of intent to session organizers. E-mail Andrew Crooks by this date if you are interested in being in this session. Please submit an abstract and key words with your expression of intent. Full submissions will be given priority over submissions with just a paper title.

October 22nd, 2009: Session finalization. Session organizers determine session order and content and notify authors.

October 26th, 2009: Final abstract submission to AAG, via www.aag.org. All participants must register individually via this site. Upon registration you will be given a participant number (PIN). Send the PIN and a copy of your final abstract to Andrew Crooks . Neither the organizers nor the AAG will edit the abstracts.

October 28th, 2009: AAG registration deadline. Sessions submitted to AAG for approval.

April 14th -18th, 2010: AAG meeting, Washington DC, USA

Jobs at CASA

CASA and the UCL Centre for Transport Studies each have a Research Associate vacancy attached to the SCALE project: (Small Changes leAd to Large Effects) Changing Energy Costs in Transport and Location Policy, funded by the EPSRC.

Click here for further details.

New Publication: Random planar graphs and the London street network

We have just had news that the work we did examining the London road network has been accepted in The European Physical Journal B: Condensed Matter and Complex Systems. The paper combines GIS and network analysis (graph theory) by Paolo Masucci, Duncan Smith, Mike Batty and myself to explore the street network of London both in its primary and dual representation.

For this research we took a radius of 27.6Km from the City of London, where the first Roman settlement was located and contains 95 percent of the population of the 33 boroughs that comprise the Greater London Authority which is also bounded by the M25 orbital road. In this way, we obtain a network we obtain a network with 163 878 intersections (the vertices), and 199 931 street segments (the edges) with 184191 nodes and 220688 links.

This data was derived from two Ordnance Survey (OS) dataset products, OS Meridian^TM 2 which includes Motorways, A Roads, B Roads and Minor Roads, and the OS Integrated Transport Network (ITN). The latter includes all the above roads but in more detail with respect to a much greater number of minor roads.

Below is the abstract:

"In this paper we analyse the street network of London both in its primary and dual representation. To understand its properties, we consider three idealised models based on a grid, a static random planar graph and a growing random planar graph. Comparing the models and the street network, we find that the streets of London form a self-organising system whose growth is characterised by a strict interaction between the metrical and informational space. In particular, a principle of least effort appears to create a balance between the physical and the mental effort required to navigate the city."

The paper can be downloaded from here, while the full reference is:

Masucci, A. P., Smith, D., Crooks, A.T. and Batty, M. (2009) Random Planar Graphs and the London Street Network, The European Physical Journal B, 71 (2): 259-271. (pdf)

News of this research also featured in the Russian Newsweek. For those who read Russian the article can be found here.

The spread of pandemics

Following on from some previous posts on the spread of pandemics (1 and 2) such as the swine flu (H1N1) and the recent article in Nature by Joshua Epstein from the Center on Social and Economic Dynamics. I just cam across this movie (below) which explores these issues in a easy to understand way.

The Brookings site is also worth exploring for those interested pandemics and public health.

There is also this spatial model from the Los Alamos National Lab who have modeled Avian flu on a supercomputer which explores vaccine and isolation options for thwarting a pandemic. Full details about the work can be seen here.

On a slightly bizarre side note there was also an interesting article on the BBC entitled "Science ponders 'zombie attack'" where researchers from the University of Ottawa showed if zombies actually existed, an attack by them would lead to the collapse of civilisation unless dealt with quickly and aggressively. The full paper can be read here.