Peter Müllner

dblp:283/5722 · also Peter Muellner · DBLP profile ↗
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7ranked-venue papers
5as first author
7since 2021 · last 2026
0000-0001-6581-1945ORCID · corroborated

Domains — the database's venue-derived domains; a paper can count in several

Databases, data management, data science and information retrieval · 5 · 4 first-author · 5 since 2021Artificial intelligence and machine learning · 2 · 2 since 2021Graphics, computer vision, multimedia, augmented reality and games · 1 · 1 since 2021Human-computer interaction and ubiquitous computing · 1 · 1 first-author · 1 since 2021
YearPublicationVenuePosition
2026 Meta-Learning and Targeted Differential Privacy to Improve the Accuracy-Privacy Trade-off in Recommendations
Peter Müllner, Dominik Kowald, Markus Schedl, Elisabeth Lex
UMAP1
2024 AI-Powered Immersive Assistance for Interactive Task Execution in Industrial Environments
abstract
Many industrial sectors rely on well-trained employees that are able to operate complex machinery. In this work, we demonstrate an immersive assistance system powered by Artificial Intelligence (AI) that supports users in performing complex tasks in industrial environments. Our system leverages a Virtual Reality (VR) environment that resembles a juice mixer setup. This digital twin of a physical setup simulates complex industrial machinery used to mix preparations or liquids (e.g., similar to the pharmaceutical industry) and includes various containers, sensors, pumps, and flow controllers. This setup demonstrates our system’s capabilities in a controlled environment while acting as a proof-of-concept for broader industrial applications. The core components of our multimodal AI assistant are a large language model and a speech-to-text model that process a video and audio recording of an expert performing the task in a VR environment. The video and speech input extracted from the expert’s video enables it to provide step-by-step guidance to support users in executing complex tasks. This demonstration showcases the potential of our AI-powered assistant to reduce cognitive load, increase productivity, and enhance safety in industrial environments.
Tomislav Duricic, Peter Müllner, Nicole Weidinger, Neven A. M. ElSayed, Dominik Kowald, Eduardo E. Veas
ECAI2
2024 The Impact of Differential Privacy on Recommendation Accuracy and Popularity Bias
abstract
Collaborative filtering-based recommender systems leverage vast amounts of behavioral user data, which poses severe privacy risks. Thus, often random noise is added to the data to ensure Differential Privacy (DP). However, to date, it is not well understood in which ways this impacts personalized recommendations. In this work, we study how DP affects recommendation accuracy and popularity bias when applied to the training data of state-of-the-art recommendation models. Our findings are three-fold: First, we observe that nearly all users’ recommendations change when DP is applied. Second, recommendation accuracy drops substantially while recommended item popularity experiences a sharp increase, suggesting that popularity bias worsens. Finally, we find that DP exacerbates popularity bias more severely for users who prefer unpopular items than for users who prefer popular items.
Peter Müllner, Elisabeth Lex, Markus Schedl, Dominik Kowald
ECIR (4)1
2024 Making Alice Appear Like Bob: A Probabilistic Preference Obfuscation Method For Implicit Feedback Recommendation Models
Gustavo Escobedo, Marta Moscati, Peter Müllner, Simone Kopeinik, Dominik Kowald, Elisabeth Lex, Markus Schedl
ECML/PKDD (7)3
2023 User Privacy in Recommender Systems
Peter Müllner
ECIR (3)1
2023 ReuseKNN: Neighborhood Reuse for Differentially Private KNN-Based Recommendations
abstract
User-based KNN recommender systems ( UserKNN ) utilize the rating data of a target user’s k nearest neighbors in the recommendation process. This, however, increases the privacy risk of the neighbors, since the recommendations could expose the neighbors’ rating data to other users or malicious parties. To reduce this risk, existing work applies differential privacy by adding randomness to the neighbors’ ratings, which unfortunately reduces the accuracy of UserKNN . In this work, we introduce ReuseKNN , a novel differentially private KNN-based recommender system. The main idea is to identify small but highly reusable neighborhoods so that (i) only a minimal set of users requires protection with differential privacy and (ii) most users do not need to be protected with differential privacy since they are only rarely exploited as neighbors. In our experiments on five diverse datasets, we make two key observations. Firstly, ReuseKNN requires significantly smaller neighborhoods and, thus, fewer neighbors need to be protected with differential privacy compared with traditional UserKNN . Secondly, despite the small neighborhoods, ReuseKNN outperforms UserKNN and a fully differentially private approach in terms of accuracy. Overall, ReuseKNN leads to significantly less privacy risk for users than in the case of UserKNN .
Peter Müllner, Elisabeth Lex, Markus Schedl, Dominik Kowald
ACM Trans. Intell. Syst. Technol.1
2021 Robustness of Meta Matrix Factorization Against Strict Privacy Constraints
Peter Müllner, Dominik Kowald, Elisabeth Lex
ECIR (2)1