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Publicações

Publicações por BIO

2020

A robust fingerprint presentation attack detection method against unseen attacks through adversarial learning

Autores
Pereira, JA; Sequeira, AF; Pernes, D; Cardoso, JS;

Publicação
2020 INTERNATIONAL CONFERENCE OF THE BIOMETRICS SPECIAL INTEREST GROUP (BIOSIG)

Abstract
Fingerprint presentation attack detection (PAD) methods present a stunning performance in current literature. However, the fingerprint PAD generalisation problem is still an open challenge requiring the development of methods able to cope with sophisticated and unseen attacks as our eventual intruders become more capable. This work addresses this problem by applying a regularisation technique based on an adversarial training and representation learning specifically designed to to improve the PAD generalisation capacity of the model to an unseen attack. In the adopted approach, the model jointly learns the representation and the classifier from the data, while explicitly imposing invariance in the high-level representations regarding the type of attacks for a robust PAD. The application of the adversarial training methodology is evaluated in two different scenarios: i) a handcrafted feature extraction method combined with a Multilayer Perceptron (MLP); and ii) an end-to-end solution using a Convolutional Neural Network (CNN). The experimental results demonstrated that the adopted regularisation strategies equipped the neural networks with increased PAD robustness. The adversarial approach particularly improved the CNN models' capacity for attacks detection in the unseen-attack scenario, showing remarkable improved APCER error rates when compared to state-of-the-art methods in similar conditions.

2020

Multivariate and Multiscale Complexity of Long-Range Correlated Cardiovascular and Respiratory Variability Series

Autores
Martins, A; Pernice, R; Amado, C; Rocha, AP; Silva, ME; Javorka, M; Faes, L;

Publicação
ENTROPY

Abstract
Assessing the dynamical complexity of biological time series represents an important topic with potential applications ranging from the characterization of physiological states and pathological conditions to the calculation of diagnostic parameters. In particular, cardiovascular time series exhibit a variability produced by different physiological control mechanisms coupled with each other, which take into account several variables and operate across multiple time scales that result in the coexistence of short term dynamics and long-range correlations. The most widely employed technique to evaluate the dynamical complexity of a time series at different time scales, the so-called multiscale entropy (MSE), has been proven to be unsuitable in the presence of short multivariate time series to be analyzed at long time scales. This work aims at overcoming these issues via the introduction of a new method for the assessment of the multiscale complexity of multivariate time series. The method first exploits vector autoregressive fractionally integrated (VARFI) models to yield a linear parametric representation of vector stochastic processes characterized by short- and long-range correlations. Then, it provides an analytical formulation, within the theory of state-space models, of how the VARFI parameters change when the processes are observed across multiple time scales, which is finally exploited to derive MSE measures relevant to the overall multivariate process or to one constituent scalar process. The proposed approach is applied on cardiovascular and respiratory time series to assess the complexity of the heart period, systolic arterial pressure and respiration variability measured in a group of healthy subjects during conditions of postural and mental stress. Our results document that the proposed methodology can detect physiologically meaningful multiscale patterns of complexity documented previously, but can also capture significant variations in complexity which cannot be observed using standard methods that do not take into account long-range correlations.

2020

B-Mode Ultrasound Breast Anatomy Segmentation

Autores
Teixeira, JF; Carreiro, AM; Santos, RM; Oliveira, HP;

Publicação
Image Analysis and Recognition - 17th International Conference, ICIAR 2020, Póvoa de Varzim, Portugal, June 24-26, 2020, Proceedings, Part II

Abstract
Breast Ultrasound has long been used to support diagnostic and exploratory procedures concerning breast cancer, with an interesting success rate, specially when complemented with other radiology information. This usability can further enhance visualization tasks during pre-treatment clinical analysis by coupling the B-Mode images to 3D space, as found in Magnetic Resonance Imaging (MRI) per instance. In fact, Lesions in B-mode are visible and present high detail when comparing with other 3D sequences. This coupling, however, would be largely benefited from the ability to match the various structures present in the B-Mode, apart from the broadly studied lesion. In this work we focus on structures such as skin, subcutaneous fat, mammary gland and thoracic region. We provide a preliminary insight to several structure segmentation approaches in the hopes of obtaining a functional and dependable pipeline for delineating these potential reference regions that will assist in multi-modal radiological data alignment. For this, we experiment with pre-processing stages that include Anisotropic Diffusion guided by Log-Gabor filters (ADLG) and main segmentation steps using K-Means, Meanshift and Watershed. Among the pipeline configurations tested, the best results were found using the ADLG filter that ran for 50 iterations and H-Maxima suppression of 20% and the K-Means method with $$K=6$$. The results present several cases that closely approach the ground truth despite overall having larger average errors. This encourages the experimentation of other approaches that could withstand the innate data variability that makes this task very challenging. © Springer Nature Switzerland AG 2020.

2020

A Breast 3D model as a possible tool for non-invasive tumour localization in breast surgery

Autores
Gouveia, P; Bessa, S; Oliveira, H; Batista, E; Aleluia, M; Ip, J; Costa, J; Nuno, L; Pinto, D; Mavioso, C; Anacleto, J; Abreu, N; Morgado, P; Martinho, M; Teixeira, J; Carvalho, P; Cardoso, J; Alves, C; Cardoso, F; Cardoso, MJ;

Publicação
EUROPEAN JOURNAL OF CANCER

Abstract

2020

Transcriptomic signatures across human tissues identify functional rare genetic variation

Autores
Aguet, F; Barbeira, AN; Bonazzola, R; Brown, A; Castel, SE; Jo, B; Kasela, S; Kim Hellmuth, S; Liang, Y; Oliva, M; Flynn, ED; Parsana, P; Fresard, L; Gamazon, ER; Hamel, AR; He, Y; Hormozdiari, F; Mohammadi, P; Muñoz Aguirre, M; Park, Y; Saha, A; Segrè, AV; Strober, BJ; Wen, X; Wucher, V; Ardlie, KG; Battle, A; Brown, CD; Cox, N; Das, S; Dermitzakis, ET; Engelhardt, BE; Garrido Martín, D; Gay, NR; Getz, GA; Guigó, R; Handsaker, RE; Hoffman, PJ; Im, HK; Kashin, S; Kwong, A; Lappalainen, T; Li, X; MacArthur, DG; Montgomery, SB; Rouhana, JM; Stephens, M; Stranger, BE; Todres, E; Viñuela, A; Wang, G; Zou, Y; Anand, S; Gabriel, S; Graubert, A; Hadley, K; Huang, KH; Meier, SR; Nedzel, JL; Nguyen, DT; Balliu, B; Conrad, DF; Cotter, DJ; deGoede, OM; Einson, J; Eskin, E; Eulalio, TY; Ferraro, NM; Gloudemans, MJ; Hou, L; Kellis, M; Li, X; Mangul, S; Nachun, DC; Nobel, AB; Park, Y; Rao, AS; Reverter, F; Sabatti, C; Skol, AD; Teran, NA; Wright, F; Ferreira, PG; Li, G; Melé, M; Yeger Lotem, E; Barcus, ME; Bradbury, D; Krubit, T; McLean, JA; Qi, L; Robinson, K; Roche, NV; Smith, AM; Sobin, L; Tabor, DE; Undale, A; Bridge, J; Brigham, LE; Foster, BA; Gillard, BM; Hasz, R; Hunter, M; Johns, C; Johnson, M; Karasik, E; Kopen, G; Leinweber, WF; McDonald, A; Moser, MT; Myer, K; Ramsey, KD; Roe, B; Shad, S; Thomas, JA; Walters, G; Washington, M; Wheeler, J; Jewell, SD; Rohrer, DC; Valley, DR; Davis, DA; Mash, DC; Branton, PA; Barker, LK; Gardiner, HM; Mosavel, M; Siminoff, LA; Flicek, P; Haeussler, M; Juettemann, T; Kent, WJ; Lee, CM; Powell, CC; Rosenbloom, KR; Ruffier, M; Sheppard, D; Taylor, K; Trevanion, SJ; Zerbino, DR; Abell, NS; Akey, J; Chen, L; Demanelis, K; Doherty, JA; Feinberg, AP; Hansen, KD; Hickey, PF; Jasmine, F; Jiang, L; Kaul, R; Kibriya, MG; Li, JB; Li, Q; Lin, S; Linder, SE; Pierce, BL; Rizzardi, LF; Smith, KS; Snyder, M; Stamatoyannopoulos, J; Tang, H; Wang, M; Carithers, LJ; Guan, P; Koester, SE; Little, AR; Moore, HM; Nierras, CR; Rao, AK; Vaught, JB; Volpi, S;

Publicação
Science

Abstract
INTRODUCTION: The human genome contains tens of thousands of rare (minor allele frequency <1%) variants, some of which contribute to disease risk. Using 838 samples with whole-genome and multitissue transcriptome sequencing data in the Genotype-Tissue Expression (GTEx) project version 8, we assessed how rare genetic variants contribute to extreme patterns in gene expression (eOutliers), allelic expression (aseOutliers), and alternative splicing (sOutliers). We integrated these three signals across 49 tissues with genomic annotations to prioritize high-impact rare variants (RVs) that associate with human traits. RATIONALE: Outlier gene expression aids in identifying functional RVs. Transcriptome sequencing provides diverse measurements beyond gene expression, including allele-specific expression and alternative splicing, which can provide additional insight into RV functional effects. RESULTS: After identifying multitissue eOutliers, aseOutliers, and sOutliers, we found that outlier individuals of each type were significantly more likely to carry an RV near the corresponding gene. Among eOutliers, we observed strong enrichment of rare structural variants. sOutliers were particularly enriched for RVs that disrupted or created a splicing consensus sequence. aseOutliers provided the strongest enrichment signal when evaluated from just a single tissue. We developed Watershed, a probabilistic model for personal genome interpretation that improves over standard genomic annotation–based methods for scoring RVs by integrating these three transcriptomic signals from the same individual and replicates in an independent cohort. To assess whether outlier RVs identified in GTEx associate with traits, we evaluated these variants for association with diverse traits in the UK Biobank, the Million Veterans Program, and the Jackson Heart Study. We found that transcriptome-assisted prioritization identified RVs with larger trait effect sizes and were better predictors of effect size than genomic annotation alone. CONCLUSION: With >800 genomes matched with transcriptomes across 49 tissues, we were able to study RVs that underlie extreme changes in the transcriptome. To capture the diversity of these extreme changes, we developed and integrated approaches to identify expression, allele-specific expression, and alternative splicing outliers, and characterized the RV landscape underlying each outlier signal. We demonstrate that personal genome interpretation and RV discovery is enhanced by using these signals. This approach provides a new means to integrate a richer set of functional RVs into models of genetic burden, improve disease gene identification, and enable the delivery of precision genomics.

2020

Combined Aerobic and Resistance Exercise in Walking Performance of Patients With Intermittent Claudication: Systematic Review

Autores
Machado, I; Sousa, N; Paredes, H; Ferreira, J; Abrantes, C;

Publicação
FRONTIERS IN PHYSIOLOGY

Abstract
Background: The short-term benefits of aerobic and resistance exercise in subjects affected by Peripheral Arterial Disease (PAD) are scarcely examined in interaction. This study aimed to identify the effects of combined aerobic and resistance exercise programs on walking performance compared with isolated aerobic exercise or with the usual care in patients with intermittent claudication. Methods: A systematic review was conducted following the PRISMA statement. A total of five electronic databases were searched (until October 2019) for randomized and non-randomized controlled trials. The focus comprised PAD patients with intermittent claudication who performed a combined aerobic and resistance exercise program that assessed the walking performance. Results: Seven studies include combined aerobic and resistance exercise vs. isolated aerobic or vs. usual care. The studies represented a sample size of 337 participants. The follow-up ranged from 4 to 12 weeks, 2 to 5 times-per-week. The risk of bias in the trials was a deemed moderate-to-high risk. After the interventions, the percent change in walking performance outcomes had a large variation. In the combined and isolated aerobic programs, the walking performance always improved, while in the usual care group oscillates between the deterioration and the improvement in all outcomes. Combined exercise and isolated aerobic exercise improved the claudication onset distance from 11 to 396%, and 30 to 422%, the absolute claudication distance from 81 to 197%, and 53 to 121%, and the maximal walking distance around 23 and 10%, respectively. Conclusions: Currently, there is insufficient evidence about the effects of combined aerobic and resistance exercise compared to isolated aerobic exercise or usual care on walking performance. However, despite the low quality of evidence, the combined aerobic and resistance exercise seems to be an effective strategy to improve walking performance in patients with intermittent claudication. These combined exercise modes or isolated aerobic exercise produce positive and significant results on walking performance. The usual care approach has a trend to deteriorate the walking performance. Thus, given the scarcity of data, new randomized controlled trial studies that include assessments of cardiovascular risk factors are urgently required to better determine the effect of this exercise combination.

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