Imperial College London


Faculty of EngineeringDyson School of Design Engineering

Senior Lecturer



+44 (0)20 7594 2584h.haddadi Website




Dyson BuildingSouth Kensington Campus






BibTex format

author = {Katevas, K and Hänsel, K and Clegg, R and Leontiadis, I and Haddadi, H and Tokarchuk, L},
title = {Finding Dory in the Crowd: Detecting Social Interactions using Multi-Modal Mobile Sensing},
url = {},

RIS format (EndNote, RefMan)

AB - Remembering our day-to-day social interactions is challenging even if youaren't a blue memory challenged fish. The ability to automatically detect andremember these types of interactions is not only beneficial for individualsinterested in their behavior in crowded situations, but also of interest tothose who analyze crowd behavior. Currently, detecting social interactions isoften performed using a variety of methods including ethnographic studies,computer vision techniques and manual annotation-based data analysis. However,mobile phones offer easier means for data collection that is easy to analyzeand can preserve the user's privacy. In this work, we present a system fordetecting stationary social interactions inside crowds, leveraging multi-modalmobile sensing data such as Bluetooth Smart (BLE), accelerometer and gyroscope.To inform the development of such system, we conducted a study with 24participants, where we asked them to socialize with each other for 45 minutes.We built a machine learning system based on gradient-boosted trees thatpredicts both 1:1 and group interactions with 77.8% precision and 86.5% recall,a 30.2% performance increase compared to a proximity-based approach. Byutilizing a community detection-based method, we further detected the variousgroup formation that exist within the crowd. Using mobile phone sensors alreadycarried by the majority of people in a crowd makes our approach particularlywell suited to real-life analysis of crowd behavior and influence strategies.
AU - Katevas,K
AU - Hänsel,K
AU - Clegg,R
AU - Leontiadis,I
AU - Haddadi,H
AU - Tokarchuk,L
TI - Finding Dory in the Crowd: Detecting Social Interactions using Multi-Modal Mobile Sensing
UR -
ER -