@ulisboa.pt
Department of Computer Science and Engineering
INESC-ID, Instituto Superior Técnico, Universidade de Lisboa
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Diogo A. P. Nunes, Dan Furrer, Sara Berger, Guillermo Cecchi, Joana Ferreira‐Gomes, et al.
European Journal of Pain, 2026
Background Placebo analgesia is a widely studied clinical phenomenon, yet placebo responses vary widely across individuals. Prior research has identified biopsychosocial factors that determine the likelihood of an individual to respond to placebo, yet generalizability and ecological validity in those studies have been limited due to the inability to account for dynamic personal and treatment effects. Methods We assessed fine‐tuned large language models (LLMs) for the prediction of placebo responses in chronic low‐back pain using contextual features extracted from patient interviews, as they speak about their lifestyle, pain, and treatment history. Interviews were conducted as part of two RCTs designed to study the placebo effect. These interviews were collected after treatment in the first trial (discovery cohort) and prior to treatment in the second trial (validation cohort). Results Semantic features extracted with LLMs can predict which individuals respond to a placebo, with an accuracy of 74% in unseen data, and validating with 70% accuracy in an independent cohort. Furthermore, in contrast to previous work, LLMs eliminated the need for pre‐selecting search terms, enabling a fully data‐driven approach, and provided interpretable insights into psychosocial factors underlying placebo responses. Conclusions These findings expand on prior research by integrating state‐of‐art NLP techniques to address limitations in interpretability and context sensitivity of the traditional methods in related work. This method highlights the role of language models to link language and psychological states, paving the way for a deeper quantitative exploration of biopsychosocial phenomena, and to understand how they relate to treatment outcomes. Significance Statement This study paves the way for a deeper yet quantitative exploration of biopsychosocial phenomena through language, and to understand how they relate to treatment outcomes, namely placebo. In this case it highlights nuanced linguistic patterns linked to responder status, which tap into semantic dimensions such as “anxiety,” “resignation,” and “hope”.
Catarina Botelho, David Gimeno-Gómez, Francisco Teixeira, John Mendonça, Patrícia Pereira, et al.
Proceedings of the Annual Conference of the International Speech Communication Association Interspeech, 2025
Eugénio Ribeiro, Ricardo Ribeiro, David Martins de Matos
Ijcai International Joint Conference on Artificial Intelligence, 2023
From the perspective of a dialog system, the identification of the intention behind the segments in a dialog is important, as it provides cues regarding the information present in the segments and how they should be interpreted. The ISO 24617-2 standard for dialog act annotation defines a hierarchically organized set of general-purpose communicative functions that correspond to different intentions that are relevant in the context of a dialog. In this paper, we explore the automatic recognition of these functions. To do so, we propose to adapt existing approaches to dialog act recognition, so that they can deal with the hierarchical classification problem. More specifically, we propose the use of an end-to-end hierarchical network with cascading outputs and maximum a posteriori path estimation to predict the communicative function at each level of the hierarchy, preserve the dependencies between the functions in the path, and decide at which level to stop. Additionally, we rely on transfer learning processes to address the data scarcity problem. Our experiments on the DialogBank show that this approach outperforms both flat and hierarchical approaches based on multiple classifiers and that each of its components plays an important role in the recognition of general-purpose communicative functions.
Diogo A.P. Nunes, Joana Ferreira-Gomes, Daniela Oliveira, Carlos Vaz, Sofia Pimenta, et al.
Proceedings IEEE Symposium on Computer Based Medical Systems, 2023
We demonstrate a proof-of-concept for the analysis of the language of chronic pain for pain intensity estimation. Importantly, we show that focus on specific words/themes is especially correlated with specific pain intensity categories. We interviewed chronic pain patients and collected demographic and clinical data. 65 patients (40 females), averaging $\\mathbf{56.4} \\pm \\mathbf{12.7}$ years of age, participated in the study. Patients reported their current pain intensity on a Visual Analogue Scale, which we discretized into 3 classes: mild, moderate, and severe pain. We extracted language features from the transcribed interview of each patient and used them to classify their pain intensity category. We measured performance with the weighted $\\mathbf{F}_{\\mathbf{1}}$ score. Finally, we analyzed potential confounding variables for internal validity. The best performing model was the Support Vector Machine with an Early Fusion of select language features, with an $\\mathbf{F}_{\\mathbf{1}}$ of 0.60, improving 39.5% upon the baseline. Patients with mild pain focused more on verbs, whilst moderate and severe pain patients focused on adverbs, and nouns and adjectives, respectively. We show that language features from patient narratives indeed convey information relevant for pain intensity estimation, and that our models can take advantage of that.
Francisco Afonso Raposo, David Martins de Matos, Ricardo Ribeiro
Neuroinformatics, 2022
Embodied Cognition (EC) states that semantics is encoded in the brain as firing patterns of neural circuits, which are learned according to the statistical structure of human multimodal experience. However, each human brain is idiosyncratically biased, according to its subjective experience, making this biological semantic machinery noisy with respect to semantics inherent to media, such as music and language. We propose to represent media semantics using low-dimensional vector embeddings by jointly modeling the functional Magnetic Resonance Imaging (fMRI) activity of several brains via Generalized Canonical Correlation Analysis (GCCA). We evaluate the semantic richness of the resulting latent space in appropriate semantic classification tasks: music genres and language topics. We show that the resulting unsupervised representations outperform the original high-dimensional fMRI voxel spaces in these downstream tasks while being more computationally efficient. Furthermore, we show that joint modeling of several subjects increases the semantic richness of the learned latent vector spaces as the number of subjects increases. Quantitative results and corresponding statistical significance testing demonstrate the instantiation of music and language semantics in the brain, thereby providing further evidence for multimodal embodied cognition as well as a method for extraction of media semantics from multi-subject brain dynamics.
Eugénio Ribeiro, Ricardo Ribeiro, David Martins de Matos
Journal of Artificial Intelligence Research, 2022
From the perspective of a dialog system, it is important to identify the intention behind the segments in a dialog, since it provides an important cue regarding the information that is present in the segments and how they should be interpreted. ISO 24617-2, the standard for dialog act annotation, defines a hierarchically organized set of general-purpose communicative functions which correspond to different intentions that are relevant in the context of a dialog. We explore the automatic recognition of these communicative functions in the DialogBank, which is a reference set of dialogs annotated according to this standard. To do so, we propose adaptations of existing approaches to flat dialog act recognition that allow them to deal with the hierarchical classification problem. More specifically, we propose the use of an end-to-end hierarchical network with cascading outputs and maximum a posteriori path estimation to predict the communicative function at each level of the hierarchy, preserve the dependencies between the functions in the path, and decide at which level to stop. Furthermore, since the amount of dialogs in the DialogBank is small, we rely on transfer learning processes to reduce overfitting and improve performance. The results of our experiments show that our approach outperforms both a flat one and hierarchical approaches based on multiple classifiers and that each of its components plays an important role towards the recognition of general-purpose communicative functions.
Francisco Afonso Raposo, David Martins de Matos, Ricardo Ribeiro
Neural Computing and Applications, 2021
Music semantics is embodied, in the sense that meaning is biologically mediated by and grounded in the human body and brain. This embodied cognition perspective also explains why music structures modulate kinetic and somatosensory perception. We explore this aspect of cognition, by considering dance as an overt expression of semantic aspects of music related to motor intention, in an artificial deep recurrent neural network that learns correlations between music audio and dance video. We claim that, just like human semantic cognition is based on multimodal statistical structures, joint statistical modeling of music and dance artifacts is expected to capture semantics of these modalities. We evaluate the ability of this model to effectively capture underlying semantics in a cross-modal retrieval task, including dance styles in an unsupervised fashion. Quantitative results, validated with statistical significance testing, strengthen the body of evidence for embodied cognition in music and demonstrate the model can recommend music audio for dance video queries and vice versa.
Diogo Vaz, David Matos, Miguel Pardal, Miguel Correia
ACM International Conference Proceeding Series, 2020
Many popular mobile applications rely on the Backend-as-a-Service (BaaS) cloud computing model to simplify the development and management of services like data storage, user authentication and notifications. However, vulnerabilities and other issues may lead to malicious operations on the mobile application client-side and malicious requests being sent to the backend, corrupting the state of the application in the cloud. To deal with these attacks after they happen and are successful, it is necessary to remove the immediate effects created by the malicious requests and subsequent effects derived from later requests. In this paper, we present MIRES, an intrusion recovery service for mobile applications based on BaaS. MIRES uses a two-phase recovery process that restores the integrity of the mobile application and minimizes its unavailability. We implemented MIRES in Android and with the Firebase platform and made experiments with 3 mobile applications that showed results of 1000 operations reverted in less than 1 minute and with the mobile application inaccessible only for less than 15 seconds.
Eugénio Ribeiro, Andreia Sofia Teixeira, Ricardo Ribeiro, David Martins de Matos
Applied Network Science, 2020
Resources such as FrameNet, which provide sets of semantic frame definitions and annotated textual data that maps into the evoked frames, are important for several NLP tasks. However, they are expensive to build and, consequently, are unavailable for many languages and domains. Thus, approaches able to induce semantic frames in an unsupervised manner are highly valuable. In this paper we approach that task from a network perspective as a community detection problem that targets the identification of groups of verb instances that evoke the same semantic frame and verb arguments that play the same semantic role. To do so, we apply a graph-clustering algorithm to a graph with contextualized representations of verb instances or arguments as nodes connected by edges if the distance between them is below a threshold that defines the granularity of the induced frames. By applying this approach to the benchmark dataset defined in the context of SemEval 2019, we outperformed all of the previous approaches to the task, achieving the current state-of-the-art performance.
Anna Pompili, Alberto Abad, David Martins de Matos, Isabel Pavao Martins
IEEE Journal on Selected Topics in Signal Processing, 2020
Clinical literature provides convincing evidence that language deficits in Alzheimer's disease (AD) allow for distinguishing patients with dementia from healthy subjects. Currently, computational approaches have widely investigated lexicosemantic aspects of discourse production, while pragmatic aspects like cohesion and coherence, are still mostly unexplored. In this article, we aim at providing a more comprehensive characterization of language abilities for the automatic identification of AD in narrative description tasks by also incorporating pragmatic aspects of speech production. To this end, we investigate the relevance of a recently proposed set of pragmatic features extracted from an automatically generated topic hierarchy graph in combination with a complementary set of state-of-the-art features encoding lexical, syntactic and semantic cues. Experimental results on the DementiaBank corpus show an accuracy improvement from 82.6% to 85.5% in identifying AD patients when pragmatic features are incorporated to the set of lexicosemantic features. Nevertheless, these results are obtained relying on manual transcriptions, which strongly limits the applicability of computational analysis to clinical settings. Thus, in this work we additionally carry out an analysis of the errors introduced by a speech recognition system and the way in which they impact the performance of the proposed method. In spite of the high word error rates obtained on these data (∼40%), automatic AD identification accuracy decreased only to 79.7%, which is considered a remarkable result when compared with solutions based on manual transcriptions.
Lrec 2020 12th International Conference on Language Resources and Evaluation Conference Proceedings, 2020
Eugénio Ribeiro, Andreia Sofia Teixeira, Ricardo Ribeiro, David Martins de Matos
Studies in Computational Intelligence, 2020
Ricardo Moura, David R. Matos, Miguel L. Pardal, Miguel Correia
IFIP Advances in Information and Communication Technology, 2020
Eugénio Ribeiro, Ricardo Ribeiro, David Martins de Matos
Journal of Artificial Intelligence Research, 2019
Miguel Vasco, Francisco S. Melo, David Martins de Matos, Ana Paiva, Tetsunari Inamura
IEEE International Conference on Intelligent Robots and Systems, 2019
Francisco Afonso Raposo, David Martins de Matos, Ricardo Ribeiro
Pattern Recognition Letters, 2019
Eugénio Ribeiro, Ricardo Ribeiro, David de Matos
Information Switzerland, 2019
Eugénio Ribeiro, Ricardo Ribeiro, David Martins de Matos
Linguamatica, 2019
Proceedings of the International Joint Conference on Autonomous Agents and Multiagent Systems Aamas, 2019
Eugénio Ribeiro, Vânia Mendonça, Ricardo Ribeiro, David Martins de Matos, Alberto Sardinha, et al.
Naacl Hlt 2019 International Workshop on Semantic Evaluation Semeval 2019 Proceedings of the 13th Workshop, 2019
David R. Matos, Miguel L. Pardal, Georg Carle, Miguel Correia
Proceedings of the 19th International Middleware Conference Middleware 2018, 2018
Hugo Rosa, David Matos, Ricardo Ribeiro, Luisa Coheur, Joao P. Carvalho
Proceedings of the International Joint Conference on Neural Networks, 2018
David R. Matos, Miguel L. Pardal, Pedro Adão, António Rito Silva, Miguel Correia
Proceedings of the Workshop on Privacy by Design in Distributed Systems P2ds 2018 Co Located with European Conference on Computer Systems Eurosys 2018, 2018
Eugénio Ribeiro, Ricardo Ribeiro, David Martins de Matos
4th International Conference Iberspeech 2018, 2018
Eugénio Ribeiro, Ricardo Ribeiro, David Martins de Matos
Lecture Notes in Computer Science Including Subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics, 2018
DAP Oliveira, L Teodoro, DM de Matos
Pattern Recognition, 113703 , 2026
2026
D Oliveira, DM de Matos
arXiv preprint arXiv:2602.21829 , 2026
2026
DAP Nunes, D Furrer, S Berger, G Cecchi, J Ferreira‐Gomes, F Neto, ...
European Journal of Pain 30 (1), e70184 , 2026
2026
Citations: 4
DAP Oliveira, E Ribeiro, D Martins de Matos
Information 16 (9), 812 , 2025
2025
Citations: 10
DAP Oliveira, DM de Matos
arXiv preprint arXiv:2507.07340 , 2025
2025
DAP Oliveira, DM de Matos
arXiv preprint arXiv:2505.10292 , 2025
2025
Citations: 5
DAP Oliveira, L Teodoro, DM de Matos
arXiv preprint arXiv:2502.13898 , 2025
2025
Citations: 7
C Botelho, D Gimeno-Gómez, F Teixeira, J Mendonça, P Pereira, ...
Proc. Interspeech 2025, 1418-1422 , 2025
2025
Citations: 4
C Botelho, D Gimeno-Gómez, F Teixeira, J Mendonça, P Pereira, ...
arXiv preprint arXiv:2501.00145 , 2024
2024
Citations: 3
DAP Nunes, J Ferreira-Gomes, F Neto, DM de Matos
arXiv preprint arXiv:2404.16226 , 2024
2024
Citations: 3
DAP Nunes, J Ferreira-Gomes, D Oliveira, C Vaz, S Pimenta, F Neto, ...
2023 IEEE 36th International Symposium on Computer-Based Medical Systems … , 2023
2023
Citations: 5
DAP Nunes, J Ferreira-Gomes, F Neto, D Martins de Matos
Information 14 (4), 237 , 2023
2023
Citations: 9
DAP Nunes, J Ferreira-Gomes, F Neto, D Martins de Matos
2023
Citations: 1
D Oliveira, DM de Matos
arXiv preprint arXiv:2210.09969 , 2022
2022
Citations: 2
FA Raposo, D Martins de Matos, R Ribeiro
Neuroinformatics 20 (2), 451-461 , 2022
2022
Citations: 3
E Ribeiro, R Ribeiro, DM de Matos
arXiv preprint arXiv:2202.03040 , 2022
2022
E Ribeiro, R Ribeiro, DM De Matos
Journal of Artificial Intelligence Research 73, 397–436-397–436 , 2022
2022
Citations: 7
F Reynaud, E Ribeiro, DM de Matos
IberSPEECH, 141-145 , 2022
2022
FA Raposo, D Martins de Matos, R Ribeiro
Neural Computing and Applications 33 (21), 14481-14493 , 2021
2021
Citations: 9
DAP Nunes, JF Gomes, F Neto, DM de Matos
arXiv preprint arXiv:2109.00402 , 2021
2021
Citations: 8
H Rosa, DM de Matos, R Ribeiro, L Coheur, JP Carvalho
IJCNN, 1-8 , 2018
2018
Citations: 94
L Marujo, W Ling, I Trancoso, C Dyer, AW Black, A Gershman, ...
Proceedings of the 53rd Annual Meeting of the Association for Computational … , 2015
2015
Citations: 86
PC Vaz, D Martins de Matos, B Martins, P Calado
Proceedings of the 12th ACM/IEEE-CS joint conference on Digital Libraries … , 2012
2012
Citations: 78
L Marujo, W Ling, R Ribeiro, A Gershman, J Carbonell, DM De Matos, ...
Knowledge-Based Systems 94, 33-42 , 2016
2016
Citations: 48
E Ribeiro, R Ribeiro, DM de Matos
arXiv preprint arXiv:1506.00839 , 2015
2015
Citations: 42
A Pompili, A Abad, DM De Matos, IP Martins
IEEE Journal of Selected Topics in Signal Processing 14 (2), 261-271 , 2020
2020
Citations: 40
N Neves, N Sebastião, D Matos, P Tomás, P Flores, N Roma
IEEE Transactions on Very Large Scale Integration (VLSI) Systems 23 (7 … , 2014
2014
Citations: 39
M Aparício, P Figueiredo, F Raposo, DM De Matos, R Ribeiro, L Marujo
Pattern Recognition Letters 73, 7-12 , 2016
2016
Citations: 34
R Ribeiro, DM de Matos
Journal of Artificial Intelligence Research 42, 275-308 , 2011
2011
Citations: 34
PV Lobo, DM De Matos
LREC 10, 1472-1475 , 2010
2010
Citations: 32
F Raposo, R Ribeiro, DM De Matos
IEEE/ACM Transactions on Audio, Speech, and Language Processing 24 (6), 1119 … , 2016
2016
Citations: 29
C Rosao, R Ribeiro, DM De Matos
ismir, 517-522 , 2012
2012
Citations: 29
PC Vaz, R Ribeiro, DM De Matos
Proceedings of the 2013 international conference on information systems and … , 2013
2013
Citations: 25
E Ribeiro, R Ribeiro, DM De Matos
Journal of Artificial Intelligence Research 66, 861-899 , 2019
2019
Citations: 24
E Ribeiro, V Mendonça, R Ribeiro, DM de Matos, A Sardinha, AL Santos, ...
Proceedings of the 13th International Workshop on Semantic Evaluation, 130-136 , 2019
2019
Citations: 24
A Mazalov, B Martins, D Matos
Proceedings of the 9th Workshop on Geographic Information Retrieval, 1-7 , 2015
2015
Citations: 23
G Carvalho, DM De Matos, V Rocio
Proceedings of the ACM first Ph. D. workshop in CIKM, 125-130 , 2007
2007
Citations: 23
PC Vaz, D Martins de Matos, B Martins
Proceedings of the fifth acm workshop on research advances in large digital … , 2012
2012
Citations: 22
R Ribeiro, DM De Matos
International Conference on Text, Speech and Dialogue, 115-122 , 2007
2007
Citations: 22
LF Garcia, LC de Oliveira, DM de Matos
Assistive Technology 28 (2), 83-92 , 2016
2016
Citations: 20