Home » Best ACM SIGMM 2023 PhD Thesis Award for Silvia Rossi

Best ACM SIGMM 2023 PhD Thesis Award for Silvia Rossi


Silvia Rossi is a postdoctoral researcher of the Distributed and Interactive Systems (DIS) group at Centrum Wiskunde & Informatica (CWI) in the Netherlands. She received her PhD from University College London (UCL), London (UK) in 2022 with a thesis on the behavioural analysis of interactive users in immersive experiences and its impact on next-generation multimedia systems. After one year as an ERCIM fellow, she is now a postdoctoral researcher as part of the European research project, TRANSMIXR (https://transmixr.eu/). She is also an active member of the multimedia community being part of the Special Interest Group of Multimedia (SIGMM) Records team. Truly passionate about multimedia and technology, her research interests are at the crossroads between multimedia processing, data processing and analysis, machine learning, and communication systems.

Thesis Abstract

Recent technological advances have opened the gate to a novel way to communicate remotely still feeling connected. In these immersive communications, humans are at the centre of virtual or augmented reality with a full sense of immersion and the possibility to interact with the new environment as well as other humans virtually present. These next-generation communication systems hide a huge potential that can invest in major economic sectors. However, they also posed many new technical challenges, mainly due to the new role of the final user: from merely passive to fully active in requesting and interacting with the content. Thus, we need to go beyond the traditional quality of experience research and develop user-centric solutions, in which the whole multimedia experience is tailored to the final interactive user. With this goal in mind, a better understanding of how people interact with immersive content is needed and it is the focus of this thesis. In this thesis, we study the behaviour of interactive users in immersive experiences and its impact on the next-generation multimedia systems. The thesis covers a deep literature review on immersive services and user centric solutions, before develop- ing three main research strands. First, we implement novel tools for behavioural analysis of users navigating in a 3-DoF Virtual Reality (VR) system. In detail, we study behavioural similarities among users by proposing a novel clustering algorithm. We also introduce information-theoretic metrics for quantifying similarities for the same viewer across contents. As a second direction, we show the impact and advantages of taking into account user behaviour in immersive systems. Specifically, we formulate optimal user centric solutions i) from a server-side perspective and ii) a navigation aware adaptation logic for VR streaming platforms. We conclude by exploiting the aforementioned behavioural studies towards a more in- interactive immersive technology: a 6-DoF VR. Overall in this thesis, experimental results based on real navigation trajectories show key advantages of understanding any hidden patterns of user interactivity to be eventually exploited in engineering user centric solutions for immersive systems.


The ACM Special Interest Group on Multimedia (SIGMM) provides a forum for researchers, engineers, and practitioners in all aspects of multimedia computing, communication, storage, and applications. SIGMM sponsors the ACM Multimedia Conference series and ad hoc workshops on emerging areas of multimedia. In addition, SIGMM supports the upcoming “ACM Transactions on Multimedia, Applications, and Computing” (TOMCCAP, early 2005) and the SIGMM Website which contains forums and other relevant material. All SIGMM publications are available through the ACM Digital Library.