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Publicações

2023

Witnessing a Forbush Decrease with a Microscintillator Ionisation Detector over the Atlantic Ocean

Autores
Tabbett, J; Aplin, K; Barbosa, S;

Publicação

Abstract
<p>A novel ionisation detector, previously deployed on meteorological radiosonde flights, has demonstrated responsivity to X-rays and gamma radiation, and additionally, is thought to be sensitive to ionising radiation from cosmic rays. The PiN detector, composed of a 1x1x0.8 cm<sup>3 </sup>CsI(Tl) microscintillator coupled to a PiN photodiode, was deployed on the NRP Sagres sailing vessel on a cruise in the Atlantic between Portugal and the Azores in 2021. The instrument can determine both the count rate and energy of incoming ionising radiation particles.</p><p>The instrument was operational during the voyage in November 2021 when a coronal mass ejection event induced a sudden decrease in the observed cosmic ray intensity, known as a Forbush decrease. We present data recorded by the ionisation detector during this period, to characterise the instrument’s ability to detect cosmic ray events, and we compare the performance with neutron monitoring stations Oulu in Finland, and Dourbes in Belgium. As the PiN detector provides spectral and count rate data, it is possible to group events by their energy, and investigate the count rates of specific energy regimes. This approach is useful as many sources – including high and low energy ionising radiation from cosmic rays – contribute to the background energy spectrum. As a result, more meaningful comparisons and relationships can be established with the neutron monitoring stations.</p>

2023

Quantum Bayesian Decision-Making

Autores
de Oliveira, M; Barbosa, LS;

Publicação
FOUNDATIONS OF SCIENCE

Abstract
As a compact representation of joint probability distributions over a dependence graph of random variables, and a tool for modelling and reasoning in the presence of uncertainty, Bayesian networks are of great importance for artificial intelligence to combine domain knowledge, capture causal relationships, or learn from incomplete datasets. Known as a NP-hard problem in a classical setting, Bayesian inference pops up as a class of algorithms worth to explore in a quantum framework. This paper explores such a research direction and improves on previous proposals by a judicious use of the utility function in an entangled configuration. It proposes a completely quantum mechanical decision-making process with a proven computational advantage. A prototype implementation in Qiskit (a Python-based program development kit for the IBM Q machine) is discussed as a proof-of-concept.

2023

Lung CT image synthesis using GANs

Autores
Mendes, J; Pereira, T; Silva, F; Frade, J; Morgado, J; Freitas, C; Negrao, E; de Lima, BF; da Silva, MC; Madureira, AJ; Ramos, I; Costa, JL; Hespanhol, V; Cunha, A; Oliveira, HP;

Publicação
EXPERT SYSTEMS WITH APPLICATIONS

Abstract
Biomedical engineering has been targeted as a potential research candidate for machine learning applications, with the purpose of detecting or diagnosing pathologies. However, acquiring relevant, high-quality, and heterogeneous medical datasets is challenging due to privacy and security issues and the effort required to annotate the data. Generative models have recently gained a growing interest in the computer vision field due to their ability to increase dataset size by generating new high-quality samples from the initial set, which can be used as data augmentation of a training dataset. This study aimed to synthesize artificial lung images from corresponding positional and semantic annotations using two generative adversarial networks and databases of real computed tomography scans: the Pix2Pix approach that generates lung images from the lung segmentation maps; and the conditional generative adversarial network (cCGAN) approach that was implemented with additional semantic labels in the generation process. To evaluate the quality of the generated images, two quantitative measures were used: the domain-specific Frechet Inception Distance and Structural Similarity Index. Additionally, an expert assessment was performed to measure the capability to distinguish between real and generated images. The assessment performed shows the high quality of synthesized images, which was confirmed by the expert evaluation. This work represents an innovative application of GAN approaches for medical application taking into consideration the pathological findings in the CT images and the clinical evaluation to assess the realism of these features in the generated images.

2023

Nudge applied to tobacco consumption : Effect on smokers and non-smokers

Autores
Moço, B; Duarte, S; Oliveira, F; Walter, CE; Freitas, R; Au-Yong-Oliveira, M;

Publicação
2023 18th Iberian Conference on Information Systems and Technologies (CISTI)

Abstract

2023

Risco de perturbações do comportamento Alimentar e Desejabilidade Social em estudantes do Ensino Superior: Comparação de estudantes de Nutrição com outros Cursos

Autores
Fernandes, Sandra; Costa, Carolina; Nakamura, Ingrid; Poínhos, Rui; Bruno M P M Oliveira;

Publicação

Abstract

2023

A review of greenwashing and supply chain management: Challenges ahead

Autores
Ines, A; Diniz, A; Moreira, AC;

Publicação
CLEANER ENVIRONMENTAL SYSTEMS

Abstract
As being environmentally responsible is a potential source of competitive advantage, incorporating genuine environmental practices across the supply chain may help firms capitalize on the growing demand for corporate accountability and consumer awareness. Therefore, it is important to understand to what extent firms are using greenwashing to mislead their stakeholders in the supply chain. The purpose of this paper is to review the existing literature regarding greenwashing in supply chain management (SCM) to shed light on the main thematic groups addressed in the literature, understand its challenges and develop a framework that highlights the key drivers that companies need to tackle to prevent greenwashing in supply chains. For this purpose, we have conducted a systematic literature review, following a three-stage method. It was possible to identify possible solutions to prevent greenwashing across four main dimensions of SCM: consumers/customers; relationships between focal firms and suppliers; certification programs and reporting assessment; and corporate leadership. We provide a framework to help firms develop their sustainable strategy and prevent greenwashing along the supply chain. This paper synthesizes the challenges that firms face when implementing a sustainable supply chain, suggests solutions to prevent greenwashing and provides future research avenues.

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