2026
Authors
Rebelo, D; Moreira, J; Farinha, JT; Nicola, S; Mota, A; Castro, H; Ferreira, LP; Bastos, J; Sá, JC; Avila, P;
Publication
JOURNAL OF QUALITY IN MAINTENANCE ENGINEERING
Abstract
PurposeIn an increasingly competitive market, equipment availability is a strategic variable for the competitiveness and success of companies. The objective of the research in this article is to present contributions to reduce unplanned production stoppages and optimise the operational efficiency of an injection moulding machine. This will be achieved by developing a systematic strategy to integrate predictive and condition-based maintenance systems with maintenance management software.Design/methodology/approachThe model developed is based on the continuous monitoring of electrical signals and vibrations, with the processing of data collected in real time through a script developed in Python. This integrates the information into the maintenance management software, facilitating a quick and accurate response to component wear conditions. The methodology employed was action research, as it was a case study developed in a real context, with active participation in development and implementation, with the aim of continuous improvement.FindingsIn August, a substantial increase was observed in the primary indicators: The mean time between failures (MTBF) increased by 97.36%, the mean time to repair (MTTR) increased by 313.31%, and the downtime was reduced by 65.04%. In December, although the figures were more moderate, significant improvements were maintained: The MTBF increased by 20%, the MTTR increased by 84%, and the downtime was reduced by 79%.Originality/valueThe findings of the study indicated that the implementation of a structured approach for the acquisition and monitoring of electrical signals and vibration data was imperative to achieve substantial gains.
2026
Authors
Nouaji, R; Bitchebe, S; Macedo, R; Balmau, O;
Publication
EuroSys
Abstract
Machine learning (ML) frameworks, such as PyTorch and TensorFlow, rely on data loaders to preprocess data before feeding it to accelerators. When preprocessing is inefficiently pipelined, GPUs can remain idle over long periods of time, leading to substantial training delays. For example, PyTorch’s default data loaders can cause up to 76% GPU idleness. A key bottleneck is the variability in preprocessing time across samples within the same dataset. Existing data loaders are oblivious to this variability, training all samples uniformly. In this case, a single slow sample can stall the entire batch, causing head-of-line blocking. We present MinatoLoader, a general-purpose data loader for PyTorch that accelerates training and improves GPU utilization under single-server, multi-GPU settings. It continuously prepares data in background and constructs batches by prioritizing fast-to-process samples, while slower samples are processed in parallel. Experiments conducted over NVIDIA V100 and A100 GPUs show that MinatoLoader accelerates training by up to 7.5× (3.6× on average) over PyTorch DataLoader and Pecan, and up to 3× (2.2× on average) over DALI. It also increases average GPU utilization from 46% with PyTorch to 90%, while preserving model accuracy and enabling faster convergence. © 2026 Copyright held by the owner/author(s)
2026
Authors
Patrício, C; Barbano, CA; Fiandrotti, A; Renzulli, R; Grangetto, M; Teixeira, LF; Neves, JC;
Publication
PATTERN RECOGNITION LETTERS
Abstract
Contrastive Analysis (CA) detects anomalies by contrasting patterns unique to a target group (e.g., unhealthy subjects) from those in a background group (e.g., healthy subjects). In the context of brain MRIs, existing CA approaches rely on supervised contrastive learning or variational autoencoders (VAEs) using both healthy and unhealthy data, but such reliance on target samples is challenging in clinical settings. Unsupervised Anomaly Detection (UAD) learns a reference representation of healthy anatomy, eliminating the need for target samples. Deviations from this reference distribution can indicate potential anomalies. In this context, diffusion models have been increasingly adopted in UAD due to their superior performance in image generation compared to VAEs. Nonetheless, precisely reconstructing the anatomy of the brain remains a challenge. In this work, we bridge CA and UAD by reformulating contrastive analysis principles for the unsupervised setting. We propose an unsupervised framework to improve the reconstruction quality by training a self-supervised contrastive encoder on healthy images to extract meaningful anatomical features. These features are used to condition a diffusion model to reconstruct the healthy appearance of a given image, enabling interpretable anomaly localization via pixel-wise comparison. We validate our approach through a proof-of-concept on a facial image dataset and further demonstrate its effectiveness on four brain MRI datasets, outperforming baseline methods in anomaly localization on the NOVA benchmark.
2026
Authors
Amado, P; Penedos-Santiago, E; Lima, C; Simoes, S; Giesteira, B; Peçaibes, V;
Publication
ARTSIT, INTERACTIVITY AND GAME CREATION, ARTSIT 2024, PT II
Abstract
This integrative literature review synthesizes insights from multiple disciplines to address the challenges and opportunities in designing digital communication interfaces for persons with Locked-In Syndrome (LIS). The paper highlights the importance of a multidisciplinary approach that includes ethical co-design, visual design principles, and Human-Computer Interaction (HCI). It emphasizes how important it is to have user-friendly, visually appealing, and accessible interfaces to help persons with LIS to communicate more effectively. Important technologies are evaluated for their potential to improve communication, including Augmented and Virtual Reality (AR & VR), Eye Tracking, and Brain-Computer Interfaces (BCI). To guarantee that the emerging technologies are both efficient and considerate of user demands, the review emphasizes the significance of ethical considerations and patient-centered design. This study intends to direct future design-based action research in constructing functional digital communication systems, using head-mounted Extended Reality (XR) technologies, by combining the various research findings from the review.
2026
Authors
Peixoto, B; Bessa, LCP; Gonçalves, G; Bessa, M; Melo, M;
Publication
FRONTIERS IN VIRTUAL REALITY
Abstract
Introduction Immersive virtual reality (iVR) offers a multisensory environment for education, yet the integration of olfaction remains underexplored. This study examined whether incorporating ambient olfactory stimuli into an iVR environment enhances foreign language vocabulary retention and the user's sense of presence.Methods A between-subjects experiment was conducted with 59 participants who learned German vocabulary in a virtual airport scenario. Participants were assigned to one of five ambient olfactory conditions systematically selected to represent distinct quadrants of the circumplex model of affect: no scent (control), spearmint (pleasant-arousing), lavender (pleasant-calming), burning wood (unpleasant-arousing), or sewage (unpleasant-calming). Vocabulary retention was measured using matching pre- and post-tests, while subjective presence was assessed using the standardised Igroup Presence Questionnaire (IPQp).Results The results indicated that ambient olfactory stimulation, regardless of affective valence or arousal level, did not significantly improve immediate vocabulary retention compared to the control condition. However, scent did impact the subjective experience of presence; notably, an unpleasant, high-arousal scent (burning wood) served as a distraction, significantly reducing perceived spatial presence.Discussion These findings establish an important boundary condition for multisensory educational VR. They demonstrate that the simple addition of ambient, affective scents as a background stimulus is insufficient to drive immediate cognitive learning gains, and may even detract from immersion if unpleasant. Multisensory iVR design must be guided by pedagogical priorities rather than novelty alone, suggesting that relying solely on ambient emotional modulation via olfaction is not a viable strategy for complex cognitive tasks.
2026
Authors
Silva, E; e Alvelos, eF; Marto, M;
Publication
Lecture Notes in Operations Research
Abstract
We consider the problem of selecting bases for firefighting activities (e.g., vigilance, water refill, initial attack) and links between them in the context of wildfire promptness. Bases can be facilities, such as watchtowers and water tanks, or positions from where an initial attack is conducted. It is assumed that it is advantageous to connect bases in such a way that resources (e.g. ground crews) can quickly move between them. The general problem is modelled in a general way as integration of a set covering problem (for selecting the location of the bases) and a travelling salesman problem where the cities are the selected locations and the arcs the links that connect them. We propose a mixed integer programming model where objectives are addressed by lexicographic optimization. The first objective is related to cover potential ignition points with a high estimate of their initial spread rate of the fire at the detection time. Computational experiments are discussed for a scenario, of an actual landscape, with parameters estimated from a fire behaviour model that takes into account slope, fuels, and wind. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2026.
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