Keynote Speakers

Franco Maria Nardini, ISTI CNR, Pisa, Italy

Title: Learned Sparse Representations of Text: A Story of Indexing and Retrieval

Abstract: In recent years, transformer-based large language models (LLMs) have fundamentally reshaped the way large textual collections are indexed and retrieved. A key driver of this transformation is the use of LLMs to learn high-dimensional, contextual sparse representations of input text. These representations are rapidly gaining popularity for several reasons: 1) they perform competitively with learned dense representations, 2) they are grounded in the LLM's vocabulary, enabling interpretability by design, and 3) they can be efficiently leveraged with a well-established data structure---the inverted index---to support fast maximum inner product search. In this talk, we will review recent advancements that enable efficient indexing and retrieval based on these sparse representations. We will then discuss current limitations and emerging challenges in this rapidly evolving area.

Bio: Franco Maria Nardini is a Senior Researcher with ISTI-CNR in Pisa, Italy. His research interests focus on Web Information Retrieval and Machine/Deep Learning. He authored over 100 papers in peer-reviewed international journals, conferences, and other venues. He has served as General Co-Chair of ECIR 2025, Program Committee Co-Chair of SPIRE 2023, and Tutorial Co-Chair of ACM WSDM 2021. He is a co-recipient of the ECIR 2025 Best Student Short Paper Award, the ACM SIGIR 2024 Best Paper Runner-Up Award, the ECIR 2022 Industry Impact Award, the ACM SIGIR 2015 Best Paper Award, and the ECIR 2014 Best Demo Paper Award. He coordinated activities in several EU and IT research projects. He is a member of the editorial board of ACM TOIS and a PC member of SIGIR, ECIR, SIGKDD, CIKM, WSDM, IJCAI, and ECML-PKDD. He currently teaches "Information Retrieval" in the Computer Science and AI Master's Degrees of the University of Pisa.

Maria Soledad Pera, TU Delft, The Netherlands

Title: “This Will All Make Sense When I’m Older”: Goals, Gaps, & the Road Ahead for Child-Aware IR

Abstract: Information Retrieval (IR) is at the core of information access systems that shape how children perceive the world and engage with digital media. Yet, these systems are rarely designed or evaluated with young users in mind; often exposing them to content that is misleading, inappropriate, or simply misaligned with their needs and developmental stages. Despite advances in IR (& AI), creating safe, effective, and age-appropriate digital experiences remains an open challenge. In this talk, we will explore how mainstream search and recommender algorithms influence children's online experiences and review current IR research aimed at addressing these gaps. We will examine how information access systems can be reimagined to better serve young users and reflect on the challenges IR researchers and practitioners face when considering underserved populations. Most importantly, we will focus on opportunities for innovation, the ethical implications of algorithmic design, and the responsibility to uphold children's rights and well-being in digital spaces.

Bio: Dr Sole Pera is an Associate Professor at the Web Information Systems group of the EEMCS faculty at TU Delft. Sole's research is in Information Retrieval, with a special emphasis on enhancing information access for underserved user groups. Sole's main area of expertise is in Information Retrieval with emphasis on non-traditional populations. Currently, her work centers on identifying the limitations and designing algorithmic support so that search and recommender systems can better serve all users, particularly children. Sole is a co-principal investigator on the SNSF-funded project “Scaffolding to foster independence when children search Online for Learning” (SOL). Sole regularly serves on the senior program committees of major conferences, including SIGIR, UMAP, RecSys, and ECIR. She is also a co-organizer of the KidRec and IR4U2 workshop series, co-located with IDC, ECIR, and SIGIR. Her service to the research community includes roles such as General Chair for RecSys’18 and IDC’23, as well as Program Chair for UMAP’23, CIKM’24, and RecSys’25.