154 research outputs found
Coherent Concept-based Explanations in Medical Image and Its Application to Skin Lesion Diagnosis
Early detection of melanoma is crucial for preventing severe complications
and increasing the chances of successful treatment. Existing deep learning
approaches for melanoma skin lesion diagnosis are deemed black-box models, as
they omit the rationale behind the model prediction, compromising the
trustworthiness and acceptability of these diagnostic methods. Attempts to
provide concept-based explanations are based on post-hoc approaches, which
depend on an additional model to derive interpretations. In this paper, we
propose an inherently interpretable framework to improve the interpretability
of concept-based models by incorporating a hard attention mechanism and a
coherence loss term to assure the visual coherence of concept activations by
the concept encoder, without requiring the supervision of additional
annotations. The proposed framework explains its decision in terms of
human-interpretable concepts and their respective contribution to the final
prediction, as well as a visual interpretation of the locations where the
concept is present in the image. Experiments on skin image datasets demonstrate
that our method outperforms existing black-box and concept-based models for
skin lesion classification.Comment: Under IEEE Copyright. Accepted for publication at CVPR 2023 Workshop
Safe Artificial Intelligence for Automated Driving (SAIAD
Associations between vocal emotion recognition and socio-emotional adjustment in children
The human voice is a primary channel for emotional communication. It is often presumed that being able to recognize vocal emotions is important for everyday socio-emotional functioning, but evidence for this assumption remains scarce. Here, we examined relationships between vocal emotion recognition and socio-emotional adjustment in children. The sample included 141 6- to 8-year-old children, and the emotion tasks required them to categorize five emotions (anger, disgust, fear, happiness, sadness, plus neutrality), as conveyed by two types of vocal emotional cues: speech prosody and non-verbal vocalizations such as laughter. Socio-emotional adjustment was evaluated by the children's teachers using a multidimensional questionnaire of self-regulation and social behaviour. Based on frequentist and Bayesian analyses, we found that, for speech prosody, higher emotion recognition related to better general socio-emotional adjustment. This association remained significant even when the children's cognitive ability, age, sex and parental education were held constant. Follow-up analyses indicated that higher emotional prosody recognition was more robustly related to the socio-emotional dimensions of prosocial behaviour and cognitive and behavioural self-regulation. For emotion recognition in non-verbal vocalizations, no associations with socio-emotional adjustment were found. A similar null result was obtained for an additional task focused on facial emotion recognition. Overall, these results support the close link between children's emotional prosody recognition skills and their everyday social behaviour
Numerical Modelling and Validation of Mixed-Mode Fracture Tests to Adhesive Joints Using J-Integral Concepts
The interest in the design and numerical modelling of adhesively-bonded components and structures for industrial application is increasing as a research topic. Although research on joint failure under pure mode is widespread, applied bonded joints are often subjected to a mixed mode loading at the crack tip, which is more complex than the pure mode and affects joint strength. Failure of these joints under loading is the objective of predictions through mathematical and numerical models, the latter based on the Finite Element Method (FEM), using Cohesive Zone Modelling (CZM). The Single leg bending (bending) testing is among those employed to study mixed mode loading. This work aims to validate the application of FEM-CZM to SLB joints. Thus, the geometries used for experimental testing were reproduced numerically and experimentally obtained properties were employed in these models. Upon the validation of the numerical technique, a parametric study involving the cohesive laws’ parameters is performed, identifying the parameters with the most influence on the joint behaviour. As a result, it was possible to numerically model SLB tests of adhesive joints and estimate the mixed-mode behaviour of different adhesives, which enables mixed-mode modelling and design of adhesive structures.info:eu-repo/semantics/publishedVersio
Mechanical characterization of Iroko wood using small specimens
Despite their favorable physical and mechanical properties for structural use, tropical woods, such as Iroko (Milicia excelsa), present knowledge gaps to be filled mainly about their mechanical characterization, which currently limit their use or result in under- or overdimensioned structural elements. Visual classification, one of the most used methods for characterizing wood, is inaccurate in the case of Iroko due to the wide variety of geographical locations in which this species can be found. In addition, mechanical characterization using test pieces with structural dimensions leads to high and impractical costs. In this context, this study aims to verify the mechanical properties of Iroko (imported from the Republic of the Congo) from small size specimens, a process that is currently standardized only for softwoods, and to verify the correlation of different properties through bending properties and ultrasound tests. Prior to the bending tests, the speed of propagation of ultrasonic waves was measured using the direct method. The results obtained show a good correlation between density and bending properties and the velocity of propagation of ultrasonic waves
Predicting olive phenology in Portugal in a warming climate
Prediction of flowering of olive trees should account for
chilling requirements, using an appropriate chilling unit
for the accounting of chilling accumulation. After chilling
requirements are satisfied, dormancy break takes place.
Thereafter, the trees enter the forcing phase, in which
the thermal time approach is used, but an appropriate
base temperature must be determined. Such a model was
developed, calibrated and validated for many olive cultivars
(De Melo-Abreu et al., 2004).
After flowering, the occurrence of developmental stages
may be predicted using a thermal time approach, but
for warm regions a saw-tooth model, which is a model
that reduces the effect of supra-optimal temperatures, is
mandatory (Garcia-Huidobro et al., :1.982).
According to the simulations of the model HadCM3,
developed by the Hadley Centre, global climate warming
will result in average temperature anomalies in winter, in
Continental Portugal, of about 2°C, in SRES scenarios 81
and 82, 3°C in scenario A2, and 4 °C in scenario A:tFI, by the
end of XXI century. (Miranda et al., 2006).
In this study, we discuss the prediction of flowering and
subsequent phenological stages and calculate and map
the times of occurrence of flowering under three warming
scenarios. No flowering or abnormal flowering events are
also predicted.Portuguese Foundation for Science and Technology (FCT) under Project Futurolive (PTDC/AGR-AAM/:1.04562/2008)
Impact of Ionic Liquid Structure and Loading on Gas Sorption and Permeation for ZIF-8-Based Composites and Mixed Matrix Membranes
Carbon dioxide (CO2) capture has become of great importance for industrial processes due
to the adverse environmental effects of gas emissions. Mixed matrix membranes (MMMs) have been
studied as an alternative to traditional technologies, especially due to their potential to overcome
the practical limitations of conventional polymeric and inorganic membranes. In this work, the
effect of using different ionic liquids (ILs) with the stable metal–organic framework (MOF) ZIF-8
was evaluated. Several IL@ZIF-8 composites and IL@ZIF-8 MMMs were prepared to improve the
selective CO2 sorption and permeation over other gases such as methane (CH4) and nitrogen (N2).
Different ILs and two distinct loadings were prepared to study not only the effect of IL concentration,
but also the impact of the IL structure and affinity towards a specific gas mixture separation. Single
gas sorption studies showed an improvement in CO2/CH4 and CO2/N2 selectivities, compared with
the ones for the pristine ZIF-8, increasing with IL loading. In addition, the prepared IL@ZIF-8 MMMs
showed improved CO2 selective behavior and mechanical strength with respect to ZIF-8 MMMs,
with a strong dependence on the intrinsic IL CO2 selectivity. Therefore, the selection of high affinity
ILs can lead to the improvement of CO2 selective separation for IL@ZIF-8 MMMsinfo:eu-repo/semantics/publishedVersio
Use of hemispherical photography for plant area index determination in young olive trees (Olea europaea L.)
O índice de área foliar (LAI) é um parâmetro
essencial para a caracterização da
estrutura das copas e consequentemente
para a avaliação da vitalidade das plantas.
Neste estudo compararam-se valores de
LAI obtidos através de métodos directos
destrutivos e através da análise de fotografia
hemisférica, em oliveiras jovens das cultivares
‘Galega’ e ‘Cordovil de Serpa’, num olival
da região de Moura.
Os valores determinados por fotografia
hemisférica subestimaram significativamente
(P<0,05) os obtidos pelas medições directas.
Assumindo que os métodos directos estimam
o LAI com maior precisão, os valores
obtidos destrutivamente foram utilizados
como referência para o cálculo de equações
de regressão entre os resultados dos métodos
indirecto e directo. A partir destas ajustaram-
se os valores determinados através da
fotografia hemisférica, de forma a permitir a
sua aplicação futura para avaliação do LAI
em oliveiras jovens. Os resultados obtidos indicam que o
método e o equipamento utilizados podem
ser adequados para a determinação do LAI
em oliveiras jovens desde que devidamente
calibrados
Impact of Ionic Liquid Structure and Loading on Gas Sorption and Permeation for ZIF-8-Based Composites and Mixed Matrix Membranes
CEECIND/ 00793/2018
LA/P/0008/2020
PTDC/CTM-TM/30326/2017Carbon dioxide (CO2) capture has become of great importance for industrial processes due to the adverse environmental effects of gas emissions. Mixed matrix membranes (MMMs) have been studied as an alternative to traditional technologies, especially due to their potential to overcome the practical limitations of conventional polymeric and inorganic membranes. In this work, the effect of using different ionic liquids (ILs) with the stable metal–organic framework (MOF) ZIF-8 was evaluated. Several IL@ZIF-8 composites and IL@ZIF-8 MMMs were prepared to improve the selective CO2 sorption and permeation over other gases such as methane (CH4) and nitrogen (N2). Different ILs and two distinct loadings were prepared to study not only the effect of IL concentration, but also the impact of the IL structure and affinity towards a specific gas mixture separation. Single gas sorption studies showed an improvement in CO2 /CH4 and CO2 /N2 selectivities, compared with the ones for the pristine ZIF-8, increasing with IL loading. In addition, the prepared IL@ZIF-8 MMMs showed improved CO2 selective behavior and mechanical strength with respect to ZIF-8 MMMs, with a strong dependence on the intrinsic IL CO2 selectivity. Therefore, the selection of high affinity ILs can lead to the improvement of CO2 selective separation for IL@ZIF-8 MMMs.publishersversionpublishe
The African hind's (Cephalopholis taeniops, serranidae) use of artificial reefs off Sal Island (Cape Verde): a preliminary study based on acoustic telemetry
The African hind Cephalopholis taeniops (Valenciennes, 1828) is one of the most important commercial demersal species caught in the Cape Verde archipelago. The species is closely associated with hard substrate and is one of the main attractions for SCUBA divers. In January 2006 a former Soviet fishing vessel - the Kwarcit - was sunk off Santa Maria Bay (Sal Island). Young C. taeniops are commonly observed in this artificial reef (AR). In order to investigate the species' use of the AR, 4 specimens were captured and surgically implanted underwater with Vemco brand acoustic transmitters. The fish were monitored daily with an active telemetry receiver for one week after release. Simultaneously, an array of 3 passive VR2 / VR2W receivers was set for 63 days, registering data that allowed an analysis of spatial, daily and short term temporal activity patterns. The results showed site fidelity to the AR, with no migrations to the nearby natural reef. The method used allowed to register a consistent higher activity during daytime and a preference for the area opposite the dominant current
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