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Publications

2022

Retinal and choroidal vasoreactivity in central serous chorioretinopathy

Authors
Penas, S; Araujo, T; Mendonca, AM; Faria, S; Silva, J; Campilho, A; Martins, ML; Sousa, V; Rocha Sousa, A; Carneiro, A; Falcao Reis, F;

Publication
GRAEFES ARCHIVE FOR CLINICAL AND EXPERIMENTAL OPHTHALMOLOGY

Abstract
Purpose This study aims to investigate retinal and choroidal vascular reactivity to carbogen in central serous chorioretinopathy (CSC) patients. Methods An experimental pilot study including 68 eyes from 20 CSC patients and 14 age and sex-matched controls was performed. The participants inhaled carbogen (5% CO2 + 95% O-2) for 2 min through a high-concentration disposable mask. A 30 degrees disc-centered fundus imaging using infra-red (IR) and macular spectral domain optical coherence tomography (SD-OCT) using the enhanced depth imaging (EDI) technique was performed, both at baseline and after a 2-min gas exposure. A parametric model fitting-based approach for automatic retinal blood vessel caliber estimation was used to assess the mean variation in both arterial and venous vasculature. Choroidal thickness was measured in two different ways: the subfoveal choroidal thickness (SFCT) was calculated using a manual caliper and the mean central choroidal thickness (MCCT) was assessed using an automatic software. Results No significant differences were detected in baseline hemodynamic parameters between both groups. A significant positive correlation was found between the participants' age and arterial diameter variation (p < 0.001, r= 0.447), meaning that younger participants presented a more vasoconstrictive response (negative variation) than older ones. No significant differences were detected in the vasoreactive response between CSC and controls for both arterial and venous vessels (p = 0.63 and p = 0.85, respectively). Although the vascular reactivity was not related to the activity of CSC, it was related to the time of disease, for both the arterial (p = 0.02, r = 0.381) and venous (p = 0.001, r= 0.530) beds. SFCT and MCCT were highly correlated (r= 0.830, p < 0.001). Both SFCT and MCCT significantly increased in CSC patients (p < 0.001 and p < 0.001) but not in controls (p = 0.059 and 0.247). A significant negative correlation between CSC patients' age and MCCT variation (r = - 0.340, p = 0.049) was detected. In CSC patients, the choroidal thickness variation was not related to the activity state, time of disease, or previous photodynamic treatment. Conclusion Vasoreactivity to carbogen was similar in the retinal vessels but significantly higher in the choroidal vessels of CSC patients when compared to controls, strengthening the hypothesis of a choroidal regulation dysfunction in this pathology.

2022

Using Evolving Ensembles to Deal with Concept Drift in Streaming Scenarios

Authors
Ramos, D; Carneiro, D; Novais, P;

Publication
INTELLIGENT DISTRIBUTED COMPUTING XIV

Abstract
In a time in which streaming data becomes the new normal in Machine Learning problems, to the detriment of batch data, new challenges arise. In the past, a data source would be static in the sense that all data were known at the moment of the training of the model. A model would be trained and it would be in use for relatively long periods of time. Nowadays, data arrive in real-time and their statistical properties may also change over time, rendering trained models outdated. In this paper we propose an approach to deal with the concept drift problem with minimal computational effort. Specifically, we continuously update an ensemble with new weak learners and adjust their weights according to their performance. This approach is suitable to be used in real-time in the form of an ever-evolving model that adapts to change in the data.

2022

Communication-efficient hierarchical federated learning for IoT heterogeneous systems with imbalanced data

Authors
Abdellatif, AA; Mhaisen, N; Mohamed, A; Erbad, A; Guizani, M; Dawy, Z; Nasreddine, W;

Publication
Future Generation Computer Systems

Abstract

2022

Enriching Legal Knowledge Through Intelligent Information Retrieval Techniques: A Review

Authors
Gomes, M; Oliveira, B; Sousa, C;

Publication
PROGRESS IN ARTIFICIAL INTELLIGENCE, EPIA 2022

Abstract
This work aims to systematize the knowledge on emerging Intelligent Information Retrieval (IIR) practices in scenarios whose context is similar to the field of tax law. It is a part of a project that covers the emerging techniques of IIR and its applicability to the tax law domain. Furthermore, it presents an overview of different approaches for representing legal data and exposes the challenging task of providing quality insights to support decision-making in a dedicated legal environment. It also offers an overview of the related background and prior research referring to the techniques for information retrieval in legal documents, establishing the current state-of-the-art, and identifying its main drawbacks. A summary of the most appropriate technologies and research approaches of the technologies that apply artificial intelligence technology to help legal tasks is also depicted.

2022

Map-Optimize-Learn: Predicting Cardiac Pathology in Children and Teenagers with a Deep Learning Based Tabular Learning Method

Authors
Neto, MTRS; Dutra, I; Mollinetti, MAF;

Publication
2022 INTERNATIONAL JOINT CONFERENCE ON NEURAL NETWORKS (IJCNN)

Abstract
Convolutional Neural Networks (CNN) have been successfully applied to images, text and audio, but their performance are not so good when applied to feature-based tabular data. Exceptions are works such as TabNet and DeepInsight, which employ end-to-end approaches. In this work, we propose an alternative way of using CNNs to model tabular data where knowledge is extracted from the feature space before being introduced to the network. Our strategy, Map-Optimize-Learn (MOL), changes the shape representation of samples in order to produce suitable input data for the CNN architecture. The strategy is applied to a real-world scenario of children and teenagers with cardiac pathology and compared against baseline and state of the art Machine Learning (ML) algorithms for tabular datasets. Preliminary results suggest that the strategy has potential to improve prediction quality of tabular data over end-to-end CNN methods and classical ML methods.

2022

REVIEW OF ENERGY AUDIT AND BENCHMARKING TOOLS TO STUDY ENERGY EFFICIENCY THROUGH REDUCING CONSUMPTION IN WASTEWATER TREATMENT SYSTEMS

Authors
Esteves, F; Cardoso, JC; Leitao, S; Pires, EJS; Baptista, J;

Publication
CADERNOS EDUCACAO TECNOLOGIA E SOCIEDADE

Abstract
Wastewater treatment systems are major consumers of electricity being responsible for 3 to 5% of global energy consumption, and 56% of greenhouse gas emissions into the atmosphere in the water treatment sector. Climate change currently imposes the definition of a new pattern of human behavior in the defense and sharing of a common space that is the planet, so the optimization of water treatment models plays a crucial role in the definition of sustainability strategies as part of the challenges for decarbonization by 2050. The physical-chemical characteristics of the influent, the treatment techniques and associated technologies and the unpredictability of external phenomena of inefficiency transform wastewater treatment plants (WWTPs) into complex systems, sometimes difficult to understand. The study of energy efficiency plays an important role in the emergence of a standard behavior model, which allows the correction of unbalanced situations in the expected energy consumption. Given the importance of the topic, the present review aims to study energy auditing techniques and benchmarking tools developed for the wastewater treatment sector to reduce the current electricity consumption, which could represent up to 90% of total energy consumption. The result of the research was organized according to the criteria defined for the characterization of auditing techniques and benchmarking tools. A review was conducted from 51 scientific papers from different reference research platforms published in the last 20 years according to the keywords. This literature review has shown that there are, in the classification of consumption reduction, energy auditing and benchmarking tools; energy management techniques and methods directed to the energy efficiency of the treatment stages and specific equipment; and, finally, decision support tools. According to the methodology followed, it was possible to conclude that although the concern is not recent, there are techniques and tools for assessing energy performance more suitable for the wastewater sector. However, the authors recognize that associated with the complexity of wastewater treatment systems, inefficiency phenomena still strongly impact energy efficiency assessment, so the contributions for their identification and quantification may represent an added value for data analysis, systematization, and optimization methodologies.

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