Hi — curious minds of the internet. I am Saber Zerhoudi, currently an Information Retrieval research scientist, based in Passau, Germany. My current research focuses on user simulation, user-centric evaluation of interactive search systems, and agentic AI.

Previously, I earned my Ph.D. at University of Passau, where I contributed to the OpenWebSearch project on large-scale, distributed web crawling and the creation of an open web index, and to the SINIR project on simulation-based evaluation of interactive search behavior in digital libraries.

I'm a user simulation and search researcher. I'm broadly interested in how we can evaluate and design information access systems from a user-centric perspective, especially now that generative models and agents are part of the picture. My work falls into three interconnected themes:

• User Simulation: I develop user simulators to model search behavior in classic and conversational settings. Notable contributions include SimIIR 2.0, SimIIR 3, and UXSim. These modular frameworks extend previous work by integrating LLM-based components and hybrid cognitive layers with traditional methods. They provide a unified testbed for systematic experimentation across diverse user types, interfaces, and tasks.

• Open Web Crawling & Indexing: I help design and operate large-scale crawling pipelines and infrastructure for the European Open Web Index, this involves the Open Web Search Crawler (OWLer) and its ecosystem for distributed, efficient crawling. Furthermore, I contribute to services exposing the Open Web Index for search, analytics, and generative AI applications.

• User-Centric RAG & Agents: I investigate agent-based retrieval-augmented generation systems that adapt to users. A central framework is PersonaRAG, which employs agents to analyze interactions and maintain user personas. This approach guides retrieval and generation processes to provide personalized, stable answers for complex questions.

Additionally, I also founded and maintain SearchSim, a small community hub that curates work on user-centric search simulation and provides TL;DR-style updates on new papers and resources.

At the University of Passau, I am involved in teaching and supporting courses in: