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Accurate Segmentation of Dermoscopic Images based on Local Binary Pattern Clustering
Publication . Pereira, Pedro M. M.; Fonseca-Pinto, Rui; Paiva, Rui Pedro; Tavora, Luis M. N.; Assunção, Pedro A. A.; Faria, Sérgio M. M. de
Segmentation is a key stage in dermoscopic image processing, where the accuracy of the border line that defines skin lesions is of utmost importance for subsequent algorithms (e.g., classification) and computer-aided early diagnosis of serious medical conditions. This paper proposes a novel segmentation method based on Local Binary Patterns (LBP), where LBP and K-Means clustering are combined to achieve a detailed delineation in dermoscopic images. In comparison with usual dermatologist-like segmentation (i.e., the available ground-truth), the proposed method is capable of finding more realistic borders of skin lesions, i.e., with much more detail. The results also exhibit reduced variability amongst different performance measures and they are consistent across different images. The proposed method can be applied for cell-based like segmentation adapted to the lesion border growing specificities. Hence, the method is suitable to follow the growth dynamics associated with the lesion border geometry in skin melanocytic images.
Body composition, strength static and isokinetic, and bone health: comparative study between active adults and amateur soccer players
Publication . Óscar M. Tavares; João P. Duarte; André O. Werneck; Daniela C. Costa; Paulo Sousa-e-Silva; Diogo Martinho; Leonardo G. O. Luz; Morouço, Pedro; João Valente-dos-Santos; Rui Soles-Gonçalves; Jorge Conde; José M. Casanova; Manuel J. Coelho-e-Silva
Objective:
To compare tissue composition, total and regional bone mineral content and bone mineral density, static hand grip and knee joint isokinetic strength between amateur soccer players and Control Group.
Methods:
Cross-sectional study. Air displacement plethysmography was used to estimate body volume and, in turn, density. Body composition, bone mineral content and bone mineral density were assessed for the whole body and at standardized regions using dual energy X-ray absorptiometry. Static grip strength was assessed with an adjustable dynamometer, and peak torque derived from isokinetic strength dynamometer (concentric muscular knee actions at 60°/s). Magnitude of the differences between groups was examined using d-Cohen.
Results:
Compared to healthy active adults, soccer players showed larger values of whole body bone mineral content (+651g; d=1.60; p<0.01). In addition, differences between groups were large for whole body bone mineral density (d=1.20 to 1.90; p<0.01): lumbar spine, i.e. L1-L4 (+19.4%), upper limbs (+8.6%) and lower limbs (+16.8%). Soccer players attained larger mean values in strength test given by static hand grip protocol (+5.6kg, d=0.99; p<0.01).
Conclusion:
Soccer adequately regulates body composition and is associated better bone health parameters (bone mineral content and density at whole-body and at particular sites exposed to mechanical loadings).
Accuracy measures for binary classification based on a quantitative variable
Publication . Santos, Rui; Felgueiras, Miguel; Martins, João Paulo; Ferreira, Liliana
The identification of the right methodology to perform binary classification based on an observed quantitative variable is usually a complex choice. Thus, the use of appropriate accuracy measures is crucial. In fact, the ROC curve reveals a lot of information about the accuracy of the applied methodology for all the possible values of the cut-point. In particular, the integral and partial areas under the ROC curve are widely used. The φ index, in which sensitivity equals specificity, may also be applied. Nevertheless, the accuracy at one specific cut-point may be sufficient to assess the accuracy in some applications. Therefore, different ways to define the optimal cut-point may be applied, such as the maximization of the Youden index, the maximization of the concordance probability or the minimization of the distance to the point with absence of misclassification. To compare the adequacy of these measures, a simulation study was performed under different scenarios. The results highlight the advantages and disadvantages of each procedure and advise the use of the φ index.
Metric Indices for Performance Evaluation of a Mixed Measurement based State Estimator
Publication . Vide, Paula Sofia; Barbosa, Fernando Pires Maciel; Carvalho, José António Beleza
With the development of synchronized phasor measurement technology in recent years, it gains great interest the use of PMU measurements to improve state estimation performances due to their synchronized characteristics and high data transmission speed The ability of the Phasor Measurement Units (PMU) to directly measure the system state is a key over SCADA measurement system. PMU measurements are superior to the conventional SCADA measurements in terms of resolution and accuracy. Since the majority of measurements in existing estimators are from conventional SCADA measurement system, it is hard to be fully replaced by PMUs in the near future so state estimators including both phasor and conventional SCADA measurements are being consideredIn this paper, a mixed measurement (SCADA and PMU measurements) state estimator is proposedSeveral useful measures for evaluating various aspects of the performance of the mixed measurement state estimator are proposed and explainedState Estimator validity, performance and characteristics of the results on IEEE 14 bus test system and IEEE 30 bus test system are presented.
Changing behavior towards physical activity and exercise
Publication . Rodrigues, Filipe; Bastos, Vasco; Teixeira, Diogo Santos; Monteiro, Diogo
A inatividade física constitui um desafio de saúde pública que resiste a décadas de intervenções focadas
meramente na educação e na decisão racional. Esta obra confronta esse paradigma, propondo uma
abordagem integradora e contemporânea sobre a ciência da mudança comportamental aplicada ao
exercício.
Partindo das limitações dos modelos sociocognitivos clássicos na explicação da "lacuna intenção comportamento", o texto aprofunda as Teorias de Duplo Processamento. A análise centra-se na
complexa interação entre sistemas reflexivos e impulsivos, explorando determinantes críticos como a
resposta afetiva ao esforço, a formação de hábitos e a tendência evolutiva para a minimização do
esforço. Argumenta-se que o comportamento humano não resulta apenas da vontade, mas de
mecanismos automáticos e hedónicos frequentemente negligenciados na prática clínica.
Através da exposição de modelos inovadores, como a Affective-Reflective Theory e o Physical Activity
Adoption and Maintenance Model, fundamenta-se a necessidade de transitar de uma prescrição técnica
para uma "arquitetura de experiências". A obra defende que a adesão sustentada depende do
alinhamento estratégico entre a cognição e a resposta afetiva, reposicionando o prazer como uma
variável clínica essencial. Trata-se de um recurso fundamental para a atualização científica de
investigadores e profissionais que procuram estratégias baseadas na evidência para promover estilos de
vida ativos.