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Publications

2026

pt-image-ir-dataset: An Image Retrieval Dataset in European Portuguese

Authors
Duarte, R; Branco, A; Proença, H; Campos, R;

Publication
ADVANCES IN INFORMATION RETRIEVAL, ECIR 2026, PT IV

Abstract
With the surge of multimodal models and the demand for effective image Information Retrieval (IR) systems, high-quality text-to-image datasets have become paramount. However, most existing datasets are primarily in English, limiting their applicability to multilingual settings. To address this, we introduce the pt-image-ir-dataset, a manually annotated resource for text-based Image IR in European Portuguese. The dataset comprises 80 diverse queries and a curated pool of 5,201 images, each annotated for relevance by multiple human judges. The proposed dataset is a step forward in supporting the development and evaluation of image IR systems for European Portuguese, addressing a clear gap in multilingual multimodal research. To this end, we have made our dataset publicly available, alongside baseline experimental results, demonstrating its suitability on the Image IR task across different retrieval paradigms, including traditional text-based lexical IR methods, semantic dense retrieval models based on language embeddings, cutting-edge vision-language models and proprietary black-box image retrieval systems. Results demonstrate that vision-language models, particularly OpenCLIP/xlm-roberta-base-ViT-B-32, significantly outperform other approaches (MRR = 0.610).

2026

Advances in Information Retrieval - 48th European Conference on Information Retrieval, ECIR 2026, Delft, The Netherlands, March 29 - April 2, 2026, Proceedings, Part II

Authors
Campos, R; Jatowt, A; Lan, Y; Aliannejadi, M; Bauer, C; MacAvaney, S; Anand, A; Ren, Z; Verberne, S; Bai, N; Mansoury, M;

Publication
ECIR (2)

Abstract

2026

Multi-Tier UAV Swarm Deployment for JRC Systems: Distributed Optimization With Learning-Based Adaptation

Authors
Abdellatif, AA; Aboeleneen, A; Abdallah, M; Fontes, H; Campos, R;

Publication
IEEE OPEN JOURNAL OF THE COMMUNICATIONS SOCIETY

Abstract
This paper proposes a multi-tier coordination framework for autonomous Unmanned Aerial Vehicle (UAV) swarm deployment in joint radar-communication (JRC)-enabled post-disaster assessment. The proposed framework adopts a distributed/coordinated optimization approach, where analytical updates are derived for the initial 3D UAV positioning and bandwidth-power allocation, jointly optimizing sensing quality and communication performance under resource constraints. Building on this foundation, a Deep Reinforcement Learning (DRL) agent is also developed to dynamically refine UAVs' positions in real time, adapting to environmental uncertainties and mission dynamics. The proposed hybrid optimization-learning framework targets the balance between optimality and complexity by enabling adaptive and intelligent decision-making for real-time and efficient deployment of distributed UAV swarms. The DRL policy adapts well to dynamic, mobile-target scenarios, while the distributed optimization enables rapid and pre-training-free deployment, making it ideal for time-critical missions. Unlike existing approaches that either rely on centralized control or neglect the interplay between sensing and communication, our framework enables distributed, infrastructure-free coordination. Simulation results show that the proposed framework achieves up to 13% and 27% higher average sensing SNR when varying the number of targets and total available power per UAV, respectively, compared to communication-centric, radar-centric, and learning-based baselines. These results confirm the effectiveness of distributed optimization and DRL-based coordination for scalable, resilient, and adaptable UAV deployment in disaster response and other mission-critical scenarios.

2026

Order allocation in online retail: Classification and literature review

Authors
Vasconcelos, S; Figueira, G; Almada-Lobo, B;

Publication
EUROPEAN JOURNAL OF OPERATIONAL RESEARCH

Abstract
Online retail is transforming the way distribution networks are managed. One prominent change is that retailers can now use their full network to fulfil orders. This process involves allocating orders to fulfilment nodes and, depending on the setting, can include other operational decisions, such as order consolidation, shipping mode selection and product substitution. This order allocation problem (OAOR) has garnered considerable attention in recent years. However, there is no comprehensive view of what has been done in the literature, nor a consistent terminology across papers, which makes it hard to position existing work and identify research gaps. To address these concerns, we conduct a systematic literature review, where we find over 60 articles contributing to the OAOR literature. From this review, we formulate the baseline problem, consider multiple extensions, and identify key problem characteristics. Additionally, we analyse and categorize the solution methods found based on the optimization mechanism, policy class, and incorporation of future information and learning. Our review points to several avenues for future research, both in problems and in solution methods.

2026

VotIE: Information Extraction from Meeting Minutes

Authors
Evans, JP; Cunha, LF; Silvano, P; Jorge, A; Guimarães, N; Nunes, S; Campos, R;

Publication
CoRR

Abstract

2026

ImageSeek: A Hybrid Text-to-Image Image Retrieval System for Domain-Specific Collections

Authors
Duarte, R; Silva, R; Branco, A; Proença, H; Campos, R;

Publication
ADVANCES IN INFORMATION RETRIEVAL, ECIR 2026, PT IV

Abstract
Large image collections are typically organized around basic metadata and keyword tags, making content discovery challenging for users seeking specific visual information. Although images may be accompanied by descriptive text, traditional retrieval systems often struggle to bridge the semantic gap between textual descriptions and visual content. In this demo, we present ImageSeek, a hybrid text-to-image retrieval system designed to enhance search effectiveness by combining text and image-based retrieval methods through an asymmetric score adjustment mechanism. The system leverages multilingual CLIP models to encode both visual and textual information, creating unified representations for cross-modal retrieval. Users can search through natural language queries in any supported language, with results ranked using a hybrid approach that treats image-based retrieval as a reliable baseline while harmonizing text-based scores through position-dependent adjustments. The demonstration system operates on a dataset of 42,333 images from the Portuguese Presidency website, providing an appropriate testbed for multimodal retrieval performance. The web application enables direct comparison between conventional CLIP-based retrieval and our hybrid approach, supporting image searches under the same conditions on external platforms, including Google Images and the Arquivo.pt image search system, enabling comparative analysis of the results. To evaluate its effectiveness, ImageSeek allows users to experience differences between retrieval modes while exploring domain-specific visual content.

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