Crowd Modelling
(updated 23rd December 2007)
Keywords: simulating people, simulating crowds, simulating crowd dynamics, workshops, simulating people, station simulation. modelling crowds
Extracts from Dr. G. Keith Still's PhD Thesis "Crowd Dynamics"
In 1994 a crowd modelling system (Legion) was developed by G. Keith Still during three years field study at Wembley Stadium (1992-1995) while working with the security staff and operations teams. The system was developed using QuickBasic and algorithms were based on simulated annealing. It could handle 30,000 entities at 20 seconds per frame for an area of 530 by 200 square metres at 30 centimetre resolution. The user could edit the screens and create basic geometries. This programme was the basis of Keith's PhD Crowd Dynamics. The original modelling system (see below) was very crude but demonstrated that the psychological parameters can be reduced to a set of rules for agent based simulations. Models included Station Simulation (Balham) and the Hong Kong Jockey Club.
Keith developed the algorithms, wrote the quick basic code and validated the system against known and observed field data for crowd dynamics. The original Crowd Dynamics system was designed as an investigation tool for the study of large scale interactive systems. The crowd modelling system (as shown below) appeared twice on the cover disk of Personal Computer World (1994 and again in 1996). This tool, which was placed in the public domain as "freeware" was NOT designed as a crowd behavioural analysis system. Over 1,000,000 million CDROM's with a copy of the this crowd modelling system were distributed via Personal Computer World.
Since then Keith has developed even more powerful tools to investigate and manage (real-time decision support tools) crowds. Myriad II has been applied to the worlds largest and most complex crowd dynamics problems from the Haj (Jamarat Bridge), real-time command and control (evacuation) of Canary Wharf and most recently the real-time decision support system used for the London New Year Fireworks.
Uses of Crowd Dynamics software around the world
UK Cabinet Office Emergency Planning College - Workshops
London New Year Fireworks (Real-Time Decision Support)
Wide Area Evacuation (Real-Time Decision Support and information system)
DWELL Time models - train loading/unloading under high density conditions
The PhD Crowd Dynamics modelling ( Dr. Still's PhD Thesis Crowd Dynamics)
This simulation shows 1000 people moving to the front of stage at Wembley Stadium. The simulation shows location (Top Screen) and Space Utilisation (Bottom Screen). Its first serious application was for Cubic Transportation Limited to model a London Underground Station for passenger operated machinery. Simulated annealing is an effective pedestrian simulation system in places of public assembly.
This model shows a typical London Underground station with a subtle change in the design (top to bottom) we can estimate the increase in flow, efficiency and space utilisation. This model is part of a validation study - commissioned by Cubic Transportation Limited.
Screen shot from my PhD thesis validation tool developed to test different types of algorithms (dual screen, two algorithms), This established the high-density bi-directional flow analysis and confirmed the shockwave dynamics in crowded environments. Details of this can be found in my PhD thesis.
The original simulation system was split over two screens - the top screen (below) shows the entity positions (yellow), the bottom screen their space utilisation (how much a point in space was being used over time). Described as a "scientific breakthrough of the highest order" back in 1998. The Crowd Dynamics modelling system was a microscopic simulation technique. Its main strength (and the theme of Dr. Still's PhD thesis) was to analyse the dynamical behaviour of crowds in complex spaces. The first prototypes displayed three screens showing flow/density and space utilisation simultaneously.
Myriad and beyond
Once you understand a system you can progress from the discovery stage and develop better, faster, more efficient tools and models for the analysis of complex spaces. Over the last decade there have been considerable advances made in the field of crowd modelling. Computers have become more powerful, memory access has extended and the wide body of scientists now working in this exciting area has led to some significant improvements in our general understanding of Crowd Dynamics.
At Crowd Dynamics Limited our work uses Myriad - a collection of tools. Myriad can produce analysis of complex spaces with minimum user inputs. It is a major advance for the process of model building, ease of use and quality of data output. See What they say about us for further information.
"I have had a chance this weekend to review your report in detail. My review confirms my initial impression of the report and the other examples on the website: that Myriad is a major advance in spatial planning, in terms of its basic approach, graphic outputs to explain the results to other players, and the speed of response." Colin Henson, Principle, Ove Arup (Australia), October 2002.
Myriad is not one tool, but a combination of many different tools and techniques (hence the name Myriad) built within a single interface. The principle of Occam's Razor should apply to all modelling techniques. Myriad modelling is firmly based in the principle of Occam's Razor - namely "when presented with a number of solutions - the simplest method is usually the best".
Agent Based Analysis of the Rajm Process (Jamarat Bridge)
Dwell Analysis using Agents