893 research outputs found
Expression Recognition with Deep Features Extracted from Holistic and Part-based Models
International audienceFacial expression recognition aims to accurately interpret facial muscle movements in affective states (emotions). Previous studies have proposed holistic analysis of the face, as well as the extraction of features pertained only to specific facial regions towards expression recognition. While classically the latter have shown better performances, we here explore this in the context of deep learning. In particular, this work provides a performance comparison of holistic and part-based deep learning models for expression recognition. In addition, we showcase the effectiveness of skip connections, which allow a network to infer from both low and high-level feature maps. Our results suggest that holistic models outperform part-based models, in the absence of skip connections. Finally, based on our findings, we propose a data augmentation scheme, which we incorporate in a part-based model. The proposed multi-face multi-part (MFMP) model leverages the wide information from part-based data augmentation, where we train the network using the facial parts extracted from different face samples of the same expression class. Extensive experiments on publicly available datasets show a significant improvement of facial expression classification with the proposed MFMP framework
A multidating approach applied to historical slackwater flood deposits of the Gardon River, SE France
A multidating approach was carried out on slackwater flood deposits, preserved in valley side rock cave and terrace, of the Gardon River in Languedoc, southeast France. Lead-210, caesium-137, and geochemical analysis of mining-contaminated slackwater flood sediments have been used to reconstruct the history of these flood deposits. These age controls were combined with the continuous record of Gardon flow since 1890, and the combined records were then used to assign ages to slackwater deposits. The stratigraphic records of terrace GE and cave GG were excellent examples to illustrate the effects of erosion/preservation in a context of a progressively self-censoring, vertically accreting sequence. The sedimentary flood record of the terrace GE located at 10 m above the channel bed is complete for years post-1958 but incomplete before. During the 78-year period 1880-1958, 25 floods of a sufficient magnitude (> 1450 m3/s) have covered the terrace. Since 1958, however, the frequency of inundation of the deposits has been lower:only 5 or 6 floods in 52 years have been large enough to exceed the necessary threshold discharge (> 1700 m3/s). The progressive increase of threshold discharge and the reduced frequency of inundation at the terrace could allow stabilisation of the vegetation cover and improved protection against erosion from subsequent large magnitude flood events. The sedimentary flood record seems complete for cave GG located at 15 m above the channel bed. Here, the low frequency of events would have enabled a high degree of stabilisation of the sedimentary flood record, rendering the deposits less susceptible to erosion. Radiocarbon dating are used in this study and compared to the other dating techniques.Eighty percent of radiocarbon dates on charcoals were considerably older than those obtained by the other techniques in the terrace. On the other hand, radiocarbon dating on seeds provided better results. This discrepancy between radiocarbon dates on charcoal and seeds is explained by the nature of the dated material (permanent wood vs. annual production and resistance to degradation process). Finally, we showed in this study that although the most common dating technique used in paleoflood hydrology is radiocarbon dating, usually on charcoal preserved within slackwater flood sediments, this method did not permitus to define a coherent age model. Only the combined use of lead-210, caesium-137, and geochemical analysis of mining-contaminated sediments with the instrumental flood record can be applied to discriminate and date the recent slackwater deposits of the terrace GE and cave GG.Une approche par datations multiples a Ă©tĂ© menĂ©e sur les dĂ©pĂŽts de sĂ©diments de crue retrouvĂ©s dans les gorges du Gardon (Languedoc). Le plomb-210, le cĂ©sium-137 et lâanalyse gĂ©ochimique des sĂ©diments contaminĂ©s par les mines ont Ă©tĂ© utilisĂ©s pour reconstruire lâhistoire des dĂ©pĂŽts de crue. Cette approche a Ă©tĂ© combinĂ©e avec lâhistorique des crues du Gardon depuis 1890 pour affiner lâapproche gĂ©ochronologique. Au niveau de la cavitĂ© GG et de la terrasse GE les analyses ont permis dâillustrer les mĂ©canismes dâĂ©rosion-redĂ©position pouvant perturber les sĂ©quences de sĂ©diments. Les enregistrements des dĂ©pĂŽts de sĂ©diments de crue sont complets sur la terrasse GE situĂ©e Ă 10 m au-dessus du lit mineur Ă partir de 1958, et incomplets auparavant. Sur la pĂ©riode 1880-1958, 25 crues ont eu un dĂ©bit suffisant (>1450 m3/s) pour recouvrir la terrasse, alors que lâon recense seulement 5 Ă 6 crues depuis 1958 (pour un dĂ©bit de submersion supĂ©rieur Ă 1700 m3/s). Lâaugmentation progressive du dĂ©bit de submersion et la frĂ©quence moindre dâinondation de la terrasse ont pu permettre sur la pĂ©riode rĂ©cente la stabilisation de la couche de surface par la vĂ©gĂ©tation et limiter lâĂ©rosion lors de crues importantes. Les enregistrements semblent complets dans la cavitĂ© GG situĂ©e Ă 15 m au-dessus du lit mineur. La frĂ©quence moindre de submersion Ă ce niveau plus Ă©levĂ© peut expliquer une meilleure stabilisation des dĂ©pĂŽts de crue, rendus moins vulnĂ©rables Ă lâĂ©rosion. La datation au radiocarbone a Ă©tĂ© testĂ©e mĂȘme si elle ne permet pas de dater avec prĂ©cision les dĂ©pĂŽts de crue des derniers siĂšcles. Sur la terrasse GE, 80% des dates au carbone 14 sur charbon de bois sont beaucoup trop vieilles par rapport aux autres techniques de datation, ce qui peut sâexpliquer par une remobilisation/dĂ©stockage de charbons de bois anciens. Les datations radiocarbone sur graines donnent de meilleurs rĂ©sultats, car issues dâune production annuelle, plus facilement dĂ©composable et moins sujette Ă des dĂ©pĂŽts intermĂ©diaires. Au final, il apparaĂźt que la technique de datation par radiocarbone sur des charbons de bois retrouvĂ©s dans les sĂ©quences sĂ©dimentaires nâest pas fiable, alors quâelle est la plus pratiquĂ©e en palĂ©o-hydrologie. Lâutilisation combinĂ©e du plomb-210, du cĂ©sium-137, de lâanalyse gĂ©ochimique des sĂ©diments et des informations sur les crues historiques a permis de discriminer et de dater les diffĂ©rents dĂ©pĂŽts de crue de ce dernier siĂšcle dans la cavitĂ© GG et la terrasse GE
Automatic Video Monitoring system for assessment of Alzheimer's Disease symptoms
International audienceIn order to fully capture the complexity of the behavioural, functioning and cognitive disturbances in Alzheimer Disease (AD) and related disorders information and communication techniques (ICT), could be of interest. This article presents using 3 clinical cases the feasibility results of an automatic video monitoring system aiming to assess subjects involved in a clinical scenario
On the external forcing of global eruptive activity in the past 300 years
The decryption of the temporal sequence of volcanic eruptions is a key step
in better anticipating future events. Volcanic activity is the result of a
complex interaction between internal and external processes, with time scales
spanning multiple orders of magnitude. We review periodicities that have been
detected or correlated with volcanic eruptions/phenomena and interpreted as
resulting from external forces. Taking a global perspective and longer time
scales than a few years, we approach this interaction by analyzing three time
series using singular spectral analysis: the global number of volcanic
eruptions (NVE) between 1700 and 2022, the number of sunspots (ISSN), a proxy
for solar activity, the polar motion (PM) and length of day (lod), two proxies
for gravitational force. Several pseudo-periodicities are common to NVE and
ISSN, in addition to the 11-year Schwabe cycle that has been reported in
previous work, but NVE shares even more periodicities with PM. These
quasi-periodic components range from ~5 to ~130 years. We interpret our
analytical results in light of the Laplace's paradigm and propose that,
similarly to the movement of Earth's rotation axis, global eruptive activity is
modulated by commensurable orbital moments of the Jovian planets, whose
influence is also detected in solar activity
Global hybrids from the semiclassical atom theory satisfying the local density linear response
We propose global hybrid approximations of the exchange-correlation (XC)
energy functional which reproduce well the modified fourth-order gradient
expansion of the exchange energy in the semiclassical limit of many-electron
neutral atoms and recover the full local density approximation (LDA) linear
response. These XC functionals represent the hybrid versions of the APBE
functional [Phys. Rev. Lett. 106, 186406, (2011)] yet employing an additional
correlation functional which uses the localization concept of the correlation
energy density to improve the compatibility with the Hartree-Fock exchange as
well as the coupling-constant-resolved XC potential energy. Broad energetical
and structural testings, including thermochemistry and geometry, transition
metal complexes, non-covalent interactions, gold clusters and small
gold-molecule interfaces, as well as an analysis of the hybrid parameters, show
that our construction is quite robust. In particular, our testing shows that
the resulting hybrid, including 20\% of Hartree-Fock exchange and named hAPBE,
performs remarkably well for a broad palette of systems and properties, being
generally better than popular hybrids (PBE0 and B3LYP). Semi-empirical
dispersion corrections are also provided.Comment: 12 pages, 4 figure
Reconstructing 15 000Â years of southern France temperatures from coupled pollen and molecular (branched glycerol dialkyl glycerol tetraether) markers (Canroute, Massif Central)
Climatic changes in southern Europe during the Holocene are characterized by a strong spatial and temporal heterogeneity whose patterns are still poorly understood, notably the presence or not of a Holocene thermal maximum (HTM; 10â000â6000âcalâBP). The climatic patterns also differ according to the proxies used (e.g. pollen, chironomid) and the latitude of the record. Here, a multi-proxy approach combining pollen and lipid biomarkers (branched glycerol dialkyl glycerol tetraethers, brGDGTs) is applied to the Canroute sedimentological sequence (Massif Central, France) to reconstruct the climatic variation over the last 15â000Â years in southern Europe. This area is poorly documented in terms of vegetation and climate change. To provide reliable climate reconstructions, we have (1)Â performed a multi-method approach applied to pollen (modern analogue technique, MAT; weighted averaging partial least squares regression, WA-PLS; boosted regression trees, BRT; and random forest, RF) and molecular biomarkers brGDGTs (five calibrations) and (2)Â investigated the role of modern databases and calibrations in climate reconstructions. Three different databases were tested for pollen data: one global database based on a Eurasian pollen database and two regional databases corresponding to MediterraneanâTemperate Europe and Temperate EuropeâScandinavian databases respectively. Five global calibrations were tested for lipid biomarkers including four for soil and one for peat. Results show that the use of different modern databases highlights the importance of considering environmental and ecological constraints when using transfer functions on pollen sequences. Pollen- and brGDGT-inferred climate trends are consistent, notably for the Late Glacial and the Early and Late Holocene. However, the reconstructions notably differ concerning the presence of a Holocene thermal maximum with the MAT pollen-based method, but no difference is apparent with the BRT pollen method nor brGDGT. The temperature reconstructions estimated from the two independent pollen and lipid proxies are then compared to regional climate signals (chironomids, pollen, molecular biomarkers) to better understand global regional climatic patterns in southern Europe. Altogether, our results from the Canroute sequence and those already available in southern Europe reveal that for the Late Glacial and Early Holocene, the regional climate trends are consistent between sites and proxies, supporting the reliability of their reconstructions despite some discrepancies. During the Holocene, the temperature signal of Canroute does not indicate the clear presence of a pronounced HTM, but rather stable temperatures.</p
Automatic Video Monitoring system for assessment of Alzheimer's Disease symptoms
International audienceIn order to fully capture the complexity of the behavioural, functioning and cognitive disturbances in Alzheimer Disease (AD) and related disorders information and communication techniques (ICT), could be of interest. This article presents using 3 clinical cases the feasibility results of an automatic video monitoring system aiming to assess subjects involved in a clinical scenario
Buffer layer-assisted growth of Ge nanoclusters on Si
In the buffer layer-assisted growth method, a condensed inert gas layer of xenon, with low-surface free energy, is used as a buffer to prevent direct interactions of deposited atoms with substrates. Because ofâŁan unusually wide applicability, the buffer layer-assisted growth method has provided a unique avenue for creation of nanostructures that are otherwise impossible to grow, and thus offered unprecedented opportunities for fundamental and applied research in nanoscale science and technology. In this article, we review recent progress in the application of the buffer layer-assisted growth method to the fabrication of Ge nanoclusters on Si substrates. In particular, we emphasize the novel configurations of the obtained Ge nanoclusters, which are characterized by the absence of a wetting layer, quasi-zero dimensionality with tunable sizes, and high cluster density in comparison with Ge nanoclusters that are formed with standard Stranski-Krastanov growth methods. The optical emission behaviors are discussed in correlation with the morphological properties
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