Quentin Hillebrand

About

I am currently a postdoctoral researcher at the University of Copenhagen, hosted by Rasmus Pagh. Previously, I completed a PhD in Computer Science at the University of Tokyo, where my thesis focused on accurate graph statistics publication under local differential privacy.

Publications

Conference Proceedings

Quentin Hillebrand, Pasin Manurangsi, Vorapong Suppakitpaisarn, and Phanu Vajanopath. Improved Differentially Private Algorithms for Rank Aggregation. AAAI 2026
Quentin Hillebrand, Vorapong Suppakitpaisarn, and Tetsuo Shibuya. Communication-Efficient Publication of Sparse Vectors under Differential Privacy via Poisson Private Representation Asia CCS 2026
Quentin Hillebrand, Vorapong Suppakitpaisarn, and Tetsuo Shibuya. Cycle Counting Under Local Differential Privacy for Degeneracy-Bounded Graphs. STACS 2025
Kevin Pfisterer, Quentin Hillebrand, and Vorapong Suppakitpaisarn. Facility Location Problem Under Local Differential Privacy Without Super-Set Assumption. DBSec 2025
Vorapong Suppakitpaisarn, Donlapark Ponnoprat, Nicha Hirankarn, and Quentin Hillebrand. Counting Graphlets of Size k under Local Differential Privacy. AISTATS 2025
Louis Betzer, Vorapong Suppakitpaisarn, and Quentin Hillebrand. Publishing Number of Walks and Katz Centrality under Local Differential Privacy. UAI 2024
Quentin Hillebrand, Vorapong Suppakitpaisarn, and Tetsuo Shibuya. Unbiased Locally Private Estimator for Polynomials of Laplacian Variables. KDD 2023

Journal Articles

Quentin Hillebrand, Vorapong Suppakitpaisarn, and Tetsuo Shibuya. Communication Cost Reduction for Subgraph Counting under Local Differential Privacy via Hash Functions. TMLR 2025

Preprints

Quentin Hillebrand, Jacob Imola, Rasmus Pagh, and Sia Sejer. Privacy by Postprocessing the Discrete Laplace Mechanism. ArXiv 2026
Kevin Pfisterer, Quentin Hillebrand, and Vorapong Suppakitpaisarn. Publishing Below-Threshold Triangle Counts under Local Weight Differential Privacy. Arxiv 2026