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Publicações

Publicações por CRACS

2022

Evolution of Heart Rate Complexity Indices in the Early Detection of Neonatal Sepsis

Autores
Ribeiro, M; Castro, L; Carrault, G; Pladys, P; Costa Santos, C; Henriques, T;

Publicação
2022 44th Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC)

Abstract

2022

Compression of Different Time Series Representations in Asphyxia Detection

Autores
Silva, B; Ribeiro, M; Henriques, TS;

Publicação
2022 10th E-Health and Bioengineering Conference, EHB 2022

Abstract
Physiological signals offer a vast amount of information about the well-being of the human system. Understanding the behavior and complexity of these signs is important for accurate assessments and diagnoses. This study focuses on fetal heart rate (FHR) analysis and its potential to detect perinatal asphyxia by analyzing how different representations of the FHR series could aid in asphyxia detection. Additionally, different compression schemes were applied to evaluate the potential of compression as a measure of complexity. For this purpose, text files containing data of the last hour of the FHR before birth were converted into different types of images (Time Series, Time Series with fixed axes, Recurrence Plot and Poincaré Plot). We then applied compression schemes for text (BZIP2 and GZIP) and images (Lempel-Ziv-Welch, DEFLATE, and JPG) in 5, 10, and 30-minute windows. Correlation analysis revealed that similar compressed formats, such as BZIP2/GZIP and TIFF LZW/TIFF DEFLATE/JPG LOSSY/JPG LOSSLESS, showed the highest values and the correlation between uncompressed and compressed formats became increasingly more negative for larger time windows. Mann-Whitney test between groups (with and without asphyxia) revealed that compressed patterned images, such as Recurrence Plots, showed the highest potential in detecting asphyxia. Moreover, we confirm that larger time windows allow for better detection, due to the presence of more detailed patterns. These findings confirmed the potential of time series image representation in detecting fetal conditions, as well as show that the compression of images leads to better results than the compression of text files. © 2022 IEEE.

2022

Entropy Analysis of Total Respiratory Time Series for Sepsis Detection

Autores
Sousa, H; Ribeiro, M; Henriques, TS;

Publicação
2022 10th E-Health and Bioengineering Conference, EHB 2022

Abstract
Neonatal sepsis is characterized by the system’s extreme response to an infection and persists as one of the biggest life-threatening diseases. The gold standard treatment is administrating an antibiotic, which, unfortunately, is often made too late. The diagnosis should be easier, faster, and achieved through non-invasive methods. Recently, entropy, a non-linear feature, has been applied to different physiological signals to detect diseases having very promising results. In this study, several entropy measures were applied to the breathing cycle duration (TTot) of the respiratory signals for 20 neonates. In total, 18 distinct methods of entropy were initially applied to 30-minute segments. Using Spearman’s correlation, it was detected strong correlation similarities between some of the measures. On the other hand, bubble, attention, phase, and spectral entropies were negatively correlated with all the other measures. To detect the presence of Sepsis, the slope of the multiscale entropy index was analyzed. Also, a changing point in the slope was probed, when possible, and then was applied linear regression to two subsets of data, before and after the changing point. Effectively, the Wilcoxon Sign Rank Test showed that the results for the total slope of the Sample, Corrected Conditional, Distribution, Permutation, Fuzzy, Gridded Distribution, Incremental, and Entropy of Entropy were statistically significant to infer that entropy decreases with time. Nonetheless, further work should confirm these results with a larger dataset that includes healthy and pathological neonates. © 2022 IEEE.

2022

The rabbit as an animal model to study innate immunity genes: Is it better than mice?

Autores
Soares, J; Pinheiro, A; Esteves, PJ;

Publicação
FRONTIERS IN IMMUNOLOGY

Abstract
The European rabbit (Oryctolagus cuniculus) was the first animal model used to understand human diseases like rabies and syphilis. Nowadays, the rabbit is still used to study several human infectious diseases like syphilis, HIV and papillomavirus. However, due to several mainly practical reasons, it has been replaced as an animal model by mice (Mus musculus). The rabbit and mouse share a recent common ancestor and are classified in the superorder Glires which arose at approximately 82 million years ago (mya). These species diverged from the Primates' ancestor at around 92 million years ago and, as such, one expects the rabbit-human and mouse-human genetic distances to be very similar. To evaluate this hypothesis, we developed a set of tools for automatic data extraction, sequence alignment and similarity study, and a web application for visualization of the resulting data. We aligned and calculated the genetic distances for 2793 innate immune system genes from human, rabbit and mouse using sequences available in the NCBI database. The obtained results show that the rabbit-human genetic distance is lower than the mouse-human genetic distance for 88% of these genes. Furthermore, when we considered only genes with a difference in genetic distance higher than 0.05, this figure increase to 93%. These results can be explained by the increase of the mutation rates in the mouse lineage suggested by some authors and clearly show that, at least looking to the genetic distance to human genes, the European rabbit is a better model to study innate immune system genes than the mouse.

2022

Blockchain-based Device Identity Management with Consensus Authentication for IoT Devices

Autores
Mukhandi M.; Damiao F.; Granjal J.; Vilela J.P.;

Publicação
Proceedings - IEEE Consumer Communications and Networking Conference, CCNC

Abstract
To decrease the IoT attack surface and provide protection against security threats such as introduction of fake IoT nodes and identity theft, IoT requires scalable device identity and authentication management. This work proposes a blockchain-based identity management approach with consensus authentication as a scalable solution for IoT device authentication management. The proposed approach relies on having a blockchain secure tamper proof ledger and a novel lightweight consensus-based identity authentication. The results show that the proposed decentralised authentication system is scalable as we increase number of nodes.

2022

Effect of User Expectation on Mobile App Privacy: A Field Study

Autores
Mendes, R; Brandao, A; Vilela, JP; Beresford, AR;

Publicação
2022 IEEE INTERNATIONAL CONFERENCE ON PERVASIVE COMPUTING AND COMMUNICATIONS (PERCOM)

Abstract
Runtime permission managers for mobile devices allow requests to be performed at the time in which permissions are required, thus enabling the user to grant/deny requests in context according to their expectations. However, in order to avoid cognitive overload, second and subsequent requests are usually automatically granted without user intervention/awareness. This paper explores whether these automated decisions fit user expectations. We performed a field study with 93 participants to collect their privacy decisions, the surrounding context and whether each request was expected. The collected 65261 permission decisions revealed a strong misalignment between apps' practices and expectation as almost half of requests are unexpected by users. This ratio strongly varies with the requested permission, the category and visibility of the requesting application and the user itself; that is, expectation is subjective to each individual. Moreover, privacy decisions are most strongly correlated with user expectation, but such correlation is also highly personal. Finally, Android's default permission manager would have violated the privacy of our participants 15% of the time.

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