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Publications

Publications by LIAAD

2024

Early Failure Detection for Air Production Unit in Metro Trains

Authors
Zafra, A; Veloso, B; Gama, J;

Publication
Hybrid Artificial Intelligent Systems - 19th International Conference, HAIS 2024, Salamanca, Spain, October 9-11, 2024, Proceedings, Part I

Abstract
Early identification of failures is a critical task in predictive maintenance, preventing potential problems before they manifest and resulting in substantial time and cost savings for industries. We propose an approach that predicts failures in the near future. First, a deep learning model combining long short-term memory and convolutional neural network architectures predicts signals for a future time horizon using real-time data. In the second step, an autoencoder based on convolutional neural networks detects anomalies in these predicted signals. Finally, a verification step ensures that a fault is considered reliable only if it is corroborated by anomalies in multiple signals simultaneously. We validate our approach using publicly available Air Production Unit (APU) data from Porto metro trains. Two significant conclusions emerge from our study. Firstly, experimental results confirm the effectiveness of our approach, demonstrating a high fault detection rate and a reduced number of false positives. Secondly, the adaptability of this proposal allows for the customization of configuration of different time horizons and relationship between the signals to meet specific detection requirements. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.

2024

Federated Online Learning for Heavy Hitter Detection

Authors
Silva, PR; Vinagre, J; Gama, J;

Publication
ECAI 2024 - 27th European Conference on Artificial Intelligence, 19-24 October 2024, Santiago de Compostela, Spain - Including 13th Conference on Prestigious Applications of Intelligent Systems (PAIS 2024)

Abstract
Effective anomaly detection in telecommunication networks is essential for securing digital transactions and supporting the sustainability of our global information ecosystem. However, the volume of data in such high-speed distributed environments imposes strict latency and scalability requirements on anomaly detection systems. This study focuses on distributed heavy hitter detection in telephone networks – a critical component of network traffic analysis and fraud detection. We propose a federated version of the Lossy Counting algorithm and compare it to its centralized version. Our experimental results reveal that the federated approach can detect considerably more unique heavy hitters than the centralized method while enhancing privacy. Furthermore, Federated Lossy Counting does not need a large amount of centralized processing power since it can leverage the networked infrastructure with minimal impact on bandwidth and computing power.

2024

A Systematic Review on Long-Tailed Learning

Authors
Zhang, C; Almpanidis, G; Fan, G; Deng, B; Zhang, Y; Liu, J; Kamel, A; Soda, P; Gama, J;

Publication
CoRR

Abstract

2024

Forecasting financial market structure from network features using machine learning

Authors
Castilho, D; Souza, TTP; Kang, SM; Gama, J; de Carvalho, ACPLF;

Publication
Knowl. Inf. Syst.

Abstract

2024

AI's effect on innovation capacity in the context of industry 5.0: a scoping review

Authors
Bécue, A; Gama, J; Brito, PQ;

Publication
Artif. Intell. Rev.

Abstract

2024

Achieving rapid and significant results in healthcare services by using the theory of constraints

Authors
Bacelar Silva, GM; Cox, JF III; Rodrigues, P;

Publication
HEALTH SYSTEMS

Abstract
Lack of timeliness and capacity are seen as fundamental problems that jeopardise healthcare delivery systems everywhere. Many believe the shortage of medical providers is causing this timeliness problem. This action research presents how one doctor implemented the theory of constraints (TOC) to improve the throughput (quantity of patients treated) of his ophthalmology imaging practice by 64% in a few weeks with little to no expense. The five focusing steps (5FS) guided the TOC implementation - which included the drum-buffer-rope scheduling and buffer management - and occurred in a matter of days. The implementation provided significant bottom-line results almost immediately. This article explains each step of the 5FS in general terms followed by specific applications to healthcare services, as well as the detailed use in this action research. Although TOC successfully addressed the practice problems, this implementation was not sustained after the TOC champion left the organisation. However, this drawback provided valuable knowledge. The article provides insightful knowledge to help readers implement TOC in their environments to provide immediate and significant results at little to no expense.

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