Published on May 25, 2021 Updated on May 25, 2021

The OPERA-Wireless Communications team reveals its recipe for MUFINS. This system, a cross between waves and AI, uses smartphone signals to detect the density of the crowd in order to predict its behaviour in Brussels during events or, more recently, during deconfinement.

This article was first published in GSquare #33, which appeared in late November 2019. In the context of the Covid-19 epidemic, the team installed its system on Rue Neuve. The City of Brussels will thus be able to monitor compliance with decontamination measures in real time and observe the evolution of the situation over the coming weeks and months.

MUFINS stands for Multi-Fidelity Intelligent Network for Crowd Monitoring. This exciting programme is part of the desire of the Opera professors to pool their research strengths to boost expertise in 5G communication and mobile location, notably by integrating their work with joint projects. MUFINS is being deployed in parallel with other achievements of the same department, such as the Amoobi spin-off (analysis of customer behaviour in shopping centres and supermarkets), or the ERDF projects and national Excellence of Science (fundamental research)...

Event-driven query

The history of MUFINS is closely linked to the invitation, nearly three years ago, of the Brussels Major Events (BME) association, the umbrella organisation for major events in the capital (Plaisirs d'Hiver, Hello Summer, Feux de Laeken, Fête de la Fédération Wallonie-Bruxelles, etc.), to collaborate with a view to better controlling and anticipating crowd movements linked to them. "The objective is safety. Studies show that beyond 2.5 to 3 people per square metre, they can no longer control their movements, and that in the presence of such a density, the probability of an incident occurring is close to 100%. It is also imperative to be able to detect any panic phenomenon as quickly as possible," explains Philippe De Doncker. Let's take the example of an event on the Grand Place in Brussels: the main method currently in use is visual counting, 'à la louche'; as soon as an observer posted on the balcony of the Town Hall considers that the threshold of 6,000 people has been reached, he issues an order to close off the site. Thanks to MUFINS, this count of the assembled population is close to exact. "Different methods are possible for this mission. BME had also thought of using camera-based crowd tracking," says François Horlin, "but our technology is less intrusive in terms of privacy protection, but also more reliable and robust depending on the weather conditions, darkness or obstruction.

The OPERA proposal

The system developed by the OPERA-Wireless Communications group is based on wifi, combined with the knowledge that nowadays few of us walk down the street without our smartphone. The latter sends out signals at regular intervals to detect nearby Wi-Fi networks, which are used - anonymised and encrypted - to determine the number of people present near a given point. This technology convinced BME during a first full-scale test at the 2017 Winter Funfest, which earned the researchers Team-Up funding from Innoviris. "Added to the support of our partner Proximus, this amount enabled us to hire two post-doctoral students over a period of two years, Jean-François Determe and Utkarsh Singh, and to acquire and parameterise a system of 30 sensors to cover an entire event in several locations", Philippe De Doncker is delighted to say.

These sensors are the hardware part of the technology. They receive the signals from the phones, count and sort them to avoid duplicates, and anonymise the data before sending it to a server via a 4G link. But the real intelligence of the system comes from the software side, which includes a web interface that allows event organisers to control the flow of their visitors at any time, but also the whole artificial intelligence (AI) part. The latter consists of the application of several algorithms on the people counting data, to allow the prediction of the crowd density (see our box).

Tomorrows that count

Since 2017, the OPERA-Wireless Communications group has multiplied its presence at events: Feux de Laeken, Fête de la Fédération Wallonie-Bruxelles, Bruxelles-les-Bains, Brussels Summer Festival 2018, etc. The MUFINS project will end in January 2020, at the end of the current edition of Plaisirs d'Hiver, where we were able to install the final system, which can be used by Brussels Major Events," says Philippe De Doncker. We now hope to be able to use it, in one form or another, with other organisations or companies.

Because the applications based on the technology could be multiplied! For example, tests have been carried out on the use of libraries at the ULB, as François Horlin explains to us... "Enrolment at the university is increasing to such an extent that it is useful to make better use of our infrastructures. Let's take the case of the libraries. Our system allows us to evaluate the number of people present on each floor. Placed online, this data would allow students to go directly to the less busy areas to study.

As for the future of MUFINS? It could be called LUMINET, the name of the project financed by Wallonia and developed in collaboration with the BEAMS department (Prof. François Quitin) of the School, the UCL and the firm Schréder. The idea of OPERA is to equip street lamps with the system, so that it is possible to inventory and classify the different types of road users in certain places. A further step towards smart cities...

Hugues Henry