Dr. Stefania Ionescu

Since January 2020, Stefania has been a member of the Social Computing Research Group. In May 2024, she finished her PhD studies (grade: summa cum laude) under the supervision of Prof. Aniko Hannak. Her thesis is titled Society as a stakeholder: understanding the societal impact of systems allocating visibility algorithmically (pdf). She has since been working as a postdoctoral researcher in the group.

In 2016, Stefania completed the Mathematical Tripos, thus receiving a BA degree from the University of Cambridge. In 2018, she received an MSc degree (grade: cum laude) in Logic, Language, and Computation from the University of Amsterdam and ILLC. There, her focus was on Theoretical Computer Science; she wrote her thesis on efficient usage of sparse knowledge in qualitative models and simulations under the joint supervision of Dr Bert Bredeweg and Dr Jaap Kamps.

Stefania is currently interested in the role of filter, search, sorting, and recommendation tools in shaping our society. Her primary goal is to find what methods are generally useful to anticipate and understand the effects of these tools on society. As such, her work spreads across various application domains (e.g., online news,  school choice, foster care) and different areas of study (e.g., Algorithmic Fairness, Recommender Systems, AI, Social Networks, Game Theory, Matching Markets). From a methodological perspective, she primarily uses simulations and theoretical analysis.

1. Ionescu S, Du Y, Joseph K, Hannak A.
   Strategic Behavior in Two-sided Matching Markets with Recommendation-enhanced Preference-formationProceedings of the 37th Conference on Neural Information Processing Systems (NeurIPS 2023).
2. Ionescu S, Hannak A, Pagan N.  Group Fairness for Content Creators: the Role of Human and Algorithmic Biases under Popularity-based Recommendations. Proceedings of the 17th ACM Conference on Recommender Systems (RecSys 2023).
3. Ionescu S, Hannak A, Pagan N. The Role of Luck in the Success of Social Media Influencers. Applied Network Science. 2023.
4. Ionescu S, Pagan N, Hannak A. Individual Fairness for Social Media Influencers. 11th International Conference on Complex Networks and their Applications 2022.
5. Joseph K, Chen HY, Ionescu S, Du Y, Sankhe P, Hannak A, Rudra A. A qualitative, network-centric method for modeling socio-technical systems, with applications to evaluating interventions on social media platforms to increase social equality. Applied Network Science. 2022 Dec;7(1):1-27.
6. Du Y, Ionescu S, Sage M, Joseph K. A Data-Driven Simulation of the New York State Foster Care System. In 2022 ACM Conference on Fairness, Accountability, and Transparency 2022 Jun 21 (pp. 1028-1038).
7. Urman A, Ionescu S, Garcia D, Hannák A. The politicization of medical preprints on Twitter during the early stages of COVID-19 pandemic. Journal of Quantitative Description: Digital Media. 2022 Feb 8;2
8. Ionescu S, Hannak A, Joseph K. An Agent-based Model to Evaluate Interventions on Online Dating Platforms to Decrease Racial Homogamy. In Proceedings of the 2021 ACM Conference on Fairness, Accountability, and Transparency 2021 Mar 3 (pp. 412-423).

• 2023: Guest lecturer for Social Computing
• 2022: Guest lecturer for Social Computing
• 2021: Guest lecturer for Social Computing
  2021: Head teaching assistant for Social Computing
• 2020: Guest lecturer for Social Computing
  2020: Teaching assistant for Social Computing
• 2019: Teaching assistant for Economics and Computation
• 2018: Teaching assistant for Economics and Computation

• Balancing fairness and revenue in ad auctions
• Signaling in Matching Markets: the effects of different interpretations of signals in the job market
• Fair and efficient signaling on satellite navigation softwares
• Using AI to improve fairness on ride-sharing platforms

In addition to the ideas listed above, Stefania is happy to work on projects based on her past papers. Moreover, you can email her if you are interested in another project that intersects with her research interests. When emailing, please make sure you include the information mentioned on the Student Projects Page. 

• 09/2021 - 04/2022. Predicting Ride-Hailing Demand: A Potential Solution For Decreasing the Income Inequality of Drivers (Christian Skorski, BSc Thesis, UZH)
• 10/2021 - 05/2022. Fairness in Online Ad Auctions: the Role of the Auction Mechanism (Simon Giesch, BSc Thesis, UZH)
• 10/2022 - 05/2023. ‘Trust Me, I Am A Doctor’: The Credibility Of Doctor Titles On Twitter (Chuqiao Yan, MSc Thesis, UZH)
• 04/2023 - 11/2023. An Agent-based Modelling Approach to Evaluate the Effects of Different Interventions on Reducing Game Addiction (Sabyasachi Banik, Ying Fan, Weihang Sun, MSc Project, UZH)
• 08/2023 - 12/2023. Fairness of Content Creators with Different Posting Frequencies: a Simulation Approach (Siqi Bao, MSc Thesis, UZH)