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Publicações

Publicações por LIAAD

2021

INNOVATIVE APPLICATIONS OF ARTIFICIAL INTELLIGENCE ON SCADA DATA

Autores
Almeida, B; Santos, J; Louro, M; Santos, M; Ribeiro, F; Bessa, J; Gouveia, C; Andrade, R; Silva, E; Rocha, N; Viana, P;

Publicação
IET Conference Proceedings

Abstract
As AI algorithms thrive on data, SCADA would be considered a natural ground for Artificial Intelligence (AI) applications to be developed, translating that avalanche of information into meaningful and fast insights to human operators. However, presently, the high complexity of the events, the data semantics, the large variety of equipment and technologies translate into very few AI applications developed in SCADA. Aware of the enormous potential yet to be explored, E-REDES partnered with INESC TEC to experiment on the development of two novel AI applications based on SCADA data. The first tool, called Alarm2Insights, identifies anomalous behaviours regarding the performance of the protection functions associated with HV and MV line panels. The second tool, called EventProfiler, uses unsupervised learning to identify similar events (i.e., with similar log messages) in HV line panels, and supervised learning to classify new events into previously defined clusters and detect unique or rare events. Aspects associated to data handling and pre-processing are also discussed. The project's results show a very promising potential of applying AI to SCADA data, enhancing the role of the operator and support him in doing better and more informed decisions. © 2021 The Institution of Engineering and Technology.

2021

Layered Learning for Acute Hypotensive Episode Prediction in the ICU: An Alternative Approach

Autores
Ribeiro, B; Cerqueira, V; Santos, R; Gamboa, H;

Publicação
2021 INTERNATIONAL CONFERENCE ON E-HEALTH AND BIOENGINEERING (EHB 2021), 9TH EDITION

Abstract
Precise machine learning models for the early identification of anomalies based on biosignal data retrieved from bedside monitors could improve intensive care, by helping clinicians make decisions in advance and produce on-time responses. However, traditional models show limitations when dealing with the high complexity of this task. Layered Learning (LL) emerges as a solution, as it consists of the hierarchical decomposition of the problem into simpler tasks. This paper explores the uncovered potential of LL in the early detection of Acute Hypotensive Episodes (AHEs). We leverage information from the MIMIC-III Database to test different subdivisions of the main task and study how to combine the outcomes from distinct layers. In addition to this, we also test a novel approach to reduce false positives in AHE predictions.

2021

Automated imbalanced classification via meta-learning

Autores
Moniz, N; Cerqueira, V;

Publicação
EXPERT SYSTEMS WITH APPLICATIONS

Abstract
Imbalanced learning is one of the most relevant problems in machine learning. However, it faces two crucial challenges. First, the amount of methods proposed to deal with such problem has grown immensely, making the validation of a large set of methods impractical. Second, it requires specialised knowledge, hindering its use by those without such level of experience. In this paper, we propose the Automated Imbalanced Classification method, ATOMIC. Such a method is the first automated machine learning approach for imbalanced classification tasks. It provides a ranking of solutions most likely to ensure an optimal approximation to a new domain, drastically reducing associated computational complexity and energy consumption. We carry this out by anticipating the loss of a large set of predictive solutions in new imbalanced learning tasks. We compare the predictive performance of ATOMIC against state-of-the-art methods using 101 imbalanced data sets. Results demonstrate that the proposed method provides a relevant approach to imbalanced learning while reducing learning and testing efforts of candidate solutions by approximately 95%.

2021

AutoFITS: Automatic Feature Engineering for Irregular Time Series

Autores
Costa, P; Cerqueira, V; Vinagre, J;

Publicação
CoRR

Abstract

2021

Forecasting hotel demand for revenue management using machine learning regression methods

Autores
Pereira, LN; Cerqueira, V;

Publicação
CURRENT ISSUES IN TOURISM

Abstract
This paper compares the accuracy of a set of 22 methods for short-term hotel demand forecasting for lead times up to 14 days ahead. Machine learning models are compared with methods ranging from seasonal naive to exponential smoothing methods for double seasonality. The machine learning methods considered include a new approach based on arbitrating, in which several forecasting models are dynamically combined to obtain predictions. Arbitrating is a metalearning approach that combines the output of experts according to predictions of the loss that they will incur. Particularly, the dynamic ensemble method is used. The methods were compared using a real time series of daily demand for a four-star hotel located in the south of Europe. The forecasting performance of those methods was assessed using three alternative accuracy measures. Results from extensive empirical experiments led us to conclude that machine learning methods outperform traditional hotel demand forecasting methods. We found that the use of machine learning models can reduce the root mean squared error up to 54% for a 1-day forecast horizon, and up to 45% for a 14-days forecast horizon, when compared with traditional exponential smoothing methods.

2021

Investigating the Effect of a Structured Intervention on the Development of Self-Care Behaviors With Arteriovenous Fistula in Hemodialysis Patients

Autores
Sousa, CN; Paquete, ARC; Teles, P; Pinto, CMCB; Dias, VFF; Ribeiro, OMPL; Manzini, CSS; Nicole, AG; Souza, LH; Ozen, N;

Publicação
CLINICAL NURSING RESEARCH

Abstract
This study aimed to assess the effectiveness of a structured intervention on the frequency of self-care behaviors with arteriovenous fistula (AVF) by patients on hemodialysis. This is a quasi-experimental study with pre- and post-measurements. Participants were assigned to an intervention group (IG) (n = 48) or to a control group (CG) (n = 41). IG patients were subject to a structured intervention on self-care with AVF (SISC-AVF) consisting of both a theoretical and a practical part. After SISC-AVF application, patients in the IG showed better overall self-care behaviors with AVF than patients in the CG (79.2% and 91.4%, respectively, p < .001) as well as better self-care concerning both the management of signs and symptoms (90.1% and 94.4% respectively, p = .004) and the prevention of complications (72.7% and 89.5%, respectively, p < .001). The study results suggest that the SISC-AVF had positive effects on patients in the IG.

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