Using bluetooth to track crowds at the Paléo music festival

Jul 22, 2013

For her semester project, an EPFL Master's student applied a different approach to tracking the flow of the crowds at the Paléo music festival – using cell phone data and statistics.

Tracking individuals in a large group, be they or humans, is no trivial task. By applying statistics to mobile phone signals picked up in a , Master's student Elisaveta Kondratieva developed a way to more accurately follow and understand the behavior of the individuals that make up the crowd. For her semester project, she evaluated an extensive dataset gathered at the 2010 Paléo music festival, revealing the potential and the pitfalls of this new approach.

Every year, the Paléo music festival attracts well over 40,000 music aficionados per day. Many carry mobile phones with activated bluetooth devices. In 2010, ten "agents," students and researchers, were part of the crowd, equipped with special mobile phones programmed to pick up and store the identity of all detectable bluetooth devices in their vicinity. The data they gathered provides a list of all of the detectable bluetooth devices surrounding each of the walking agents at any given time throughout the evening.

Often, these data are not enough to discriminate between different nearby locations. Were the detected individuals at the Asian food stall, the stand right next to it, or were they on the way to their next concert? Detecting the presence of bluetooth signals narrows down the position of the mobile phone that emits it, and that of its owner, to a radius around 10 to 20 meters around the agent. The inaccuracy of the agent's GPS adds up to 10 more meters of uncertainty. Furthermore, many devices were only detected a handful of times in the course of the evening.

This is where statistics come in handy. "Using an approach based on Bayesian statistics, that is by taking into account certain pieces of available information, the accuracy of the outcome can be improved," she says. Concert schedules, a of the festival grounds, and other sources of information can help fill in the gaps between separate detections and provide likely estimates of the exact locations of the individuals.

For such an approach to work, a significant fraction of the audience have to have their set to be detectable. Fortunately, this turned out to be the case: fixed detectors at the entrance to the festival detected over 3,300 devices - just over 8% of the 40,500 people that attended the festival that day.

The quality of the results depends largely on how effectively the agents fan out across the festival grounds. "Two of our agents basically spent the entire evening at the festival together," says the student, "so the data they obtained overlapped. Also, none of our agents ever went to one of the more remote stages." To fix these loopholes, future campaigns could involve a larger number of fixed detectors and mobile agents. Additionally, a similar approach could be adopted to follow individuals using their WiFi signals.

Explore further: Key decisions on drones likely from Congress

add to favorites email to friend print save as pdf

Related Stories

Calgary rolls out Bluetooth travel time system

Dec 09, 2012

(Phys.org)—The City of Calgary, Alberta, now uses Bluetooth-based tracking to give people real-time information about travel time during their commute. The system collects information from Bluetooth devices ...

Comedy Central to launch Twitter comedy festival

Apr 22, 2013

Putting a new test to the adage that brevity is the soul of wit, Comedy Central is partnering with Twitter for a comedy festival played out in 140 characters and 6-second videos.

IPhone 4S first phone for low-power Bluetooth

Oct 24, 2011

The iPhone 4S has a little-heralded feature that makes it unique among phones, at least for a while: It can talk to a new class of wireless devices, such as watches and glucose and heart-rate monitors.

Recommended for you

Key decisions on drones likely from Congress

7 hours ago

The Obama administration is on the verge of proposing long-awaited rules for commercial drone operations in U.S. skies, but key decisions on how much access to grant drones are likely to come from Congress ...

Building a machine that sorts candy colors with iPhone

Dec 23, 2014

The very idea of a machine being able to color-sort M&Ms teases an inventor's imagination and interest in machines, electronics and programming. A person with a website called "reviewmylife" had heard about ...

Laser technology aids CO2 storage capabilities

Dec 23, 2014

DOE's National Energy Technology Laboratory is attracting private industry attention and winning innovation awards for harnessing the power of lasers to monitor the safe and permanent underground storage ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.