Uppsala Universitet
Inspired by the way
people move at heavy metal concerts, an international team of researchers from
Uppsala University and Harvard University have learned how to spot danger zones
in mass gatherings before disaster strikes.
Publishing online in
the journal Physical Review Letters Nov. 23rd, Uppsala
University's graduate student Arianna Bottinelli, and professor in applied
mathematics David Sumpter, have developed computational tools to predict
large-scale collective motion in simulated mass gatherings.
The team started with simulated crowds so they could reliably keep track of everyone's position. "From this data, we're able to predict the most risky collective motions that naturally arise in a dense shoulder-to-shoulder crowd," says first author Bottinelli, who will defend her PhD thesis in applied mathematics on the 25th of November.
Sumpter adds,
"The next step is to apply these techniques to real-time video data. If we
can use computer vision to track people, then our analytical tools can warn
event planners of potential hazards before they arise."
Overwhelmingly, mass
gatherings are held without incident. But sometimes things go wrong. People can
be trampled or asphyxiated by crushing pressures generated by the crowd itself.
These types of collective motion have been previously studied, but the new
physics-based insights in this work provide an explanation for how these
disasters occur in the first place.
Bottinelli, who lead
the research, describes it like this: "It all comes down to way people
gather into a randomly packed group. Physical body-to-body contacts are the
foundation for potentially dangerous collective motion. Our work shows how to
identify the emergent risks based on which people are touching each
other."
The project started as
a study in the way people "dance" at heavy metal concerts. These
"mosh pits" forcefully separate the crowd, creating areas near the
stage where the crowd is densely packed.
"We were staring
at the concert data when we realized there were direct similarities with
rallies, protests, and Black Friday sales events," said Dr. Silverberg,
postdoctoral fellow at Harvard University, who has been collaborating on this
work.
"The more we dug, the richer the physics became. Pretty soon we
found ideas from material science and field theory could be applied directly to
human crowds in extreme situations," he adds. The researchers noted that
awareness is the key to safety. With the Black Friday shopping holiday
in America and the general increase in protest events across the globe, there
are increasingly hidden dangers in crowds. The team's conclusions and
suggestion to the public is to "keep an eye on your surroundings -- if
you're packed densely, then there's an inherent risk, and the best way to
protect yourself and others is to spread out and move to an area with more
physical space" the team concluded.
The research,
"Emergent structural mechanisms for high-density collective motion
inspired by human crowds" was supported by the Centre for
Interdisciplinary Mathematics in Uppsala University, Sweden.
