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Publications

2021

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

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

Publication
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

A Review of Graph-Based Models for Entity-Oriented Search

Authors
Devezas, JL; Nunes, S;

Publication
SN Comput. Sci.

Abstract
Entity-oriented search tasks heavily rely on exploiting unstructured and structured collections. Moreover, it is frequent for text corpora and knowledge bases to provide complementary views on a common topic. While, traditionally, the retrieval unit was the document, modern search engines have evolved to also retrieve entities and to provide direct answers to the information needs of the users. Cross-referencing information from heterogeneous sources has become fundamental, however a mismatch still exists between text-based and knowledge-based retrieval approaches. The former does not account for complex relations, while the latter does not properly support keyword-based queries and ranked retrieval. Graphs are a good solution to this problem, since they can be used to represent text, entities and their relations. In this survey, we examine text-based approaches and how they evolved to leverage entities and their relations in the retrieval process. We also cover multiple aspects of graph-based models for entity-oriented search, providing an overview on link analysis and exploring graph-based text representation and retrieval, leveraging knowledge graphs for document or entity retrieval, building entity graphs from text, using graph matching for querying with subgraphs, exploiting hypergraph-based representations, and ranking based on random walks on graphs. We close with a discussion on the topic and a view of the future to motivate the research of graph-based models for entity-oriented search, particularly as joint representation models for the generalization of retrieval tasks.

2021

PREFAB Framework - PRoduct quality towards zEro deFects for melAmine surface Boards industry

Authors
Dias, RC; Senna, PP; Goncalves, AF; Reis, J; Michalaros, N; Alexopoulos, K; Gomes, M;

Publication
IFAC PAPERSONLINE

Abstract
Zero Defects is one of the ultimate targets for manufacturing quality control and assurance. Such systems are becoming common in advanced manufacturing industries but are at an initial stage in more traditional industrial sectors, such as wood panels, laminates production, pulp and paper processing and composite panels production. This paper proposes the PREFAB framework, applied to the wood based panels industry, to minimize rejected products using AI, machine learning and IoT devices. The framework was built through action research with a Portuguese wood-based panel manufacturing. This framework delivered an innovative decision support system that provides relevant and timely recommendations for shopfloor decision making and to support process/product engineering. Copyright (C) 2021 The Authors.

2021

Anomaly Detection in Cyber-Physical Systems: Reconstruction of a Prediction Error Feature Space

Authors
Oliveira, N; Sousa, N; Oliveira, J; Praca, I;

Publication
2021 14TH INTERNATIONAL CONFERENCE ON SECURITY OF INFORMATION AND NETWORKS (SIN 2021)

Abstract
Cyber-physical systems are infrastructures that use digital information such as network communications and sensor readings to control entities in the physical world. Many cyber-physical systems in airports, hospitals and nuclear power plants are regarded as critical infrastructures since a disruption of its normal functionality can result in negative consequences for the society. In the last few years, some security solutions for cyber-physical systems based on artificial intelligence have been proposed. Nevertheless, knowledge domain is required to properly setup and train artificial intelligence algorithms. Our work proposes a novel anomaly detection framework based on error space reconstruction, where genetic algorithms are used to perform hyperparameter optimization of machine learning methods. The proposed method achieved an Fl-score of 87.89% in the SWaT dataset.

2021

Mobility as a Service (MaaS): Past and Present Challenges and Future Opportunities

Authors
Amaral, A; Barreto, L; Baltazar, S; Pereira, T;

Publication
Advances in Intelligent Systems and Computing

Abstract
Recently, Mobility as a Service (MaaS) concept and its main theoretical approaches have been under discussion, to positively influence the future of mobility. Namely, by contextualizing MaaS’s role in modern societies explaining its main functions, characteristics, and attributes, as well as identifying all the stakeholders involved in this comprehensive challenge towards ensuring its widespread implementation. The environmental, societal, technological and cultural changes needed to ensure a sustainable mobility ecosystem are an utmost challenge that requires an intense effort and involvement of all different types of stakeholders within their perspectives, roles, responsibilities and contributions to the mobility system overall behavior and performance. Notwithstanding, the global tendency of digital transformation, also referred as digitization, in society and businesses are upbringing a new technological evolution that will lead to a new mobility paradigm bringing together MaaS and the internet of Mobility (IoM), thus creating what we call the Internet of Mobility as a Service (IoMaaS). The future trends of mobility will have to be ‘human-centric’, to properly balance the amount of technology requested into the ecosystem to ensure the whole system’s universality, to be inclusive, as well as developing the appropriate amount of technology, accordingly to the different users’ technological skills. Furthermore, different types of incentives and penalties need to be included in supporting a broad cultural shift regarding citizen’s mobility routines habits. This will be of great importance to ensure the sustainability of this new mobility paradigm as well as of the ability to attain all its benefits. © 2021, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG.

2021

Simple Matrix Factorization Collaborative Filtering for Drug Repositioning on Cell Lines

Authors
Carrera, I; Tejera, E; Dutra, I;

Publication
HEALTHINF: PROCEEDINGS OF THE 14TH INTERNATIONAL JOINT CONFERENCE ON BIOMEDICAL ENGINEERING SYSTEMS AND TECHNOLOGIES - VOL. 5: HEALTHINF

Abstract
The discovery of new biological interactions, such as interactions between drugs and cell lines, can improve the way drugs are developed. Recently, there has been important interest for predicting interactions between drugs and targets using recommender systems; and more specifically, using recommender systems to predict drug activity on cellular lines. In this work, we present a simple and straightforward approach for the discovery of interactions between drugs and cellular lines using collaborative filtering. We represent cellular lines by their drug affinity profile, and correspondingly, represent drugs by their cell line affinity profile in a single interaction matrix. Using simple matrix factorization, we predicted previously unknown values, minimizing the regularized squared error. We build a comprehensive dataset with information from the ChEMBL database. Our dataset comprises 300,000+ molecules, 1,200+ cellular lines, and 3,000,000+ reported activities. We have been able to successfully predict drug activity, and evaluate the performance of our model via utility, achieving an Area Under ROC Curve (AUROC) of near 0.9.

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