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Publicações

Publicações por Guilherme Moreira Aresta

2015

Optical Flow Based Approach for Automatic Cardiac Cycle Estimation in Ultrasound Images of the Carotid

Autores
Araujo, T; Aresta, G; Rouco, J; Ferreira, C; Azevedo, E; Campilho, A;

Publicação
IMAGE ANALYSIS AND RECOGNITION (ICIAR 2015)

Abstract
This paper proposes a method to detect a reference frame in an ultrasound video of the carotid artery. This reference frame, usually located at the end of the diastole, is used as the location to measure several vascular biomarkers. Our approach is based on the analysis of the movement of the carotid walls in ultrasound images using an optical flow technique. A periodic movement resembling heart beat is observed in the resulting signals. The comparison of these signals with electrocardiograms validates the proposed method for detecting the reference frame.

2017

Classification of breast cancer histology images using Convolutional Neural Networks

Autores
Araujo, T; Aresta, G; Castro, E; Rouco, J; Aguiar, P; Eloy, C; Polonia, A; Campilho, A;

Publicação
PLOS ONE

Abstract

2017

Improving convolutional neural network design via variable neighborhood search

Autores
Araujo, T; Aresta, G; Almada Lobo, B; Mendonca, AM; Campilho, A;

Publicação
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

Abstract
An unsupervised method for convolutional neural network (CNN) architecture design is proposed. The method relies on a variable neighborhood search-based approach for finding CNN architectures and hyperparameter values that improve classification performance. For this purpose, t-Distributed Stochastic Neighbor Embedding (t-SNE) is applied to effectively represent the solution space in 2D. Then, k-Means clustering divides this representation space having in account the relative distance between neighbors. The algorithm is tested in the CIFAR-10 image dataset. The obtained solution improves the CNN validation loss by over 15% and the respective accuracy by 5%. Moreover, the network shows higher predictive power and robustness, validating our method for the optimization of CNN design. © Springer International Publishing AG 2017.

2017

Detection of juxta-pleural lung nodules in computed tomography images

Autores
Aresta, G; Cunha, A; Campilho, A;

Publicação
Medical Imaging 2017: Computer-Aided Diagnosis

Abstract

2016

Effects of hypergravity on the angiogenic potential of endothelial cells

Autores
Costa Almeida, R; Carvalho, DTO; Ferreira, MJS; Aresta, G; Gomes, ME; van Loon, JJWA; Van der Heiden, K; Granja, PL;

Publicação
Journal of the Royal Society Interface

Abstract
Angiogenesis, the formation of blood vessels from pre-existing ones, is a key event in pathology, including cancer progression, but also in homeostasis and regeneration. As the phenotype of endothelial cells (ECs) is continuously regulated by local biomechanical forces, studying endothelial behaviour in altered gravity might contribute to new insights towards angiogenesis modulation. This study aimed at characterizing EC behaviour after hypergravity exposure (more than 1g), with special focus on cytoskeleton architecture and capillary-like structure formation. Herein, human umbilical vein ECs (HUVECs) were cultured under two-dimensional and three-dimensional conditions at 3g and 10g for 4 and 16 h inside the large diameter centrifuge at the European Space Research and Technology Centre (ESTEC) of the European Space Agency. Although no significant tendency regarding cytoskeleton organization was observed for cells exposed to high g's, a slight loss of the perinuclear localization of b-tubulin was observed for cells exposed to 3g with less pronounced peripheral bodies of actin when compared with 1g control cells. Additionally, hypergravity exposure decreased the assembly of HUVECs into capillary-like structures, with a 10g level significantly reducing their organization capacity. In conclusion, short-term hypergravity seems to affect EC phenotype and their angiogenic potential in a time and g-level-dependent manner.

2018

Towards an Automatic Lung Cancer Screening System in Low Dose Computed Tomography

Autores
Aresta, G; Araujo, T; Jacobs, C; van Ginneken, B; Cunha, A; Ramos, I; Campilho, A;

Publicação
Image Analysis for Moving Organ, Breast, and Thoracic Images - Third International Workshop, RAMBO 2018, Fourth International Workshop, BIA 2018, and First International Workshop, TIA 2018, Held in Conjunction with MICCAI 2018, Granada, Spain, September 16 and 20, 2018, Proceedings

Abstract

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