Automatic facial expression recognition is essential for many potential applications. Thus, having a clear overview on existing datasets that have been investigated within the framework of face ...expression recognition is of paramount importance in designing and evaluating effective solutions, notably for neural networks-based training. In this survey, we provide a review of more than eighty facial expression datasets, while taking into account both macro- and micro-expressions. The proposed study is mostly focused on spontaneous and in-the-wild datasets, given the common trend in the research is that of considering contexts where expressions are shown in a spontaneous way and in a real context. We have also provided instances of potential applications of the investigated datasets, while putting into evidence their pros and cons. The proposed survey can help researchers to have a better understanding of the characteristics of the existing datasets, thus facilitating the choice of the data that best suits the particular context of their application.
Infrastructure networks have become increasingly complex, whose progressively higher levels of interdependence make them even more vulnerable. This empirical analysis based on the Morandi bridge ...collapse examines the robustness and vulnerability of the motorway and railway networks in north-western Italy. By following a network topology-based approach, motorways and railways are studied as one single interconnected multi-layer transport infrastructure. Based on the concepts of geographic and functional interdependence the study provides insight into which nodes (and links) should be restored as quickly as possible when an emergency and destructive event renders them inaccessible. Moreover, it highlights the greater fragility of the intermodal network which opens up the debate on regulation and coordination of restoring measures carried out by the relevant authorities.
For decades, researchers of different areas, ranging from artificial intelligence to computer vision, have intensively investigated human-centered data, i ....
The popular Mogi model, describing deformation due to a small pressurized spherical cavity embedded in a homogeneous elastic half-space, is shortly reviewed, similarities and differences with other ...isotropic deformation models are discussed and the interpretation of the different volume changes accompanying source inflation is provided. The model is then generalized to viscoelastic rheology. The overpressure needed within the source to reproduce the large deformation, sometimes observed in volcanic regions, is found to be strongly dependent on rheological parameters, so that reasonably low values may be obtained if the relaxation time of the medium surrounding the source is short (months), instead of the extremely high values inferred from the elastic theory. If the inflation of the source is due to the input of new magma from remote distance, the resulting residual gravity change Δ
g may be easily computed, thanks to the spherical geometry of the source, and the density of the newly emplaced material may be inferred from the ratio of Δ
g/
w, between the gravity change and the uplift. This ratio is independent of the overpressure and the radius of the source, which are generally ill defined parameters, and is slightly dependent on the relaxation time in the transient phase. Explicit solutions are shown for a step-like overpressure history and for a constant magma supply rate. A more realistic model is also proposed, in which the viscoelastic properties are restricted to a small spherical volume around the source, surrounded by an elastic medium. Even if an accurate interpretation of deformation and gravity changes in volcanic areas generally requires taking into account topography, elastic layering and the triaxial geometry of the inflation source, values computed according to the generalized Mogi model are compared with observations made during the 1982–84 uplift episode at Campi Flegrei caldera (Italy), for the sake of illustration.
Facial Action Units (AUs) correspond to the deformation/contraction of individual facial muscles or their combinations. As such, each AU affects just a small portion of the face, with deformations ...that are asymmetric in many cases. Generating and analyzing AUs in 3D is particularly relevant for the potential applications it can enable. In this paper, we propose a solution for 3D AU detection and synthesis by developing on a newly defined 3D Morphable Model (3DMM) of the face. Differently from most of the 3DMMs existing in the literature, which mainly model global variations of the face and show limitations in adapting to local and asymmetric deformations, the proposed solution is specifically devised to cope with such difficult morphings. During a training phase, the deformation coefficients are learned that enable the 3DMM to deform to 3D target scans showing neutral and facial expression of the same individual, thus decoupling expression from identity deformations. Then, such deformation coefficients are used, on the one hand, to train an AU classifier, on the other, they can be applied to a 3D neutral scan to generate AU deformations in a subject-independent manner. The proposed approach for AU detection is validated on the Bosphorus dataset, reporting competitive results with respect to the state-of-the-art, even in a challenging cross-dataset setting. We further show the learned coefficients are general enough to synthesize realistic 3D face instances with AUs activation.
We study the electrical and morphological properties of random arrays of Ge nanowires (NW) deposited on sapphire substrates. NW-based devices were fabricated with the aim of developing ...chemiresistive-type sensors for the detection of explosive vapours. We present the results obtained on pristine and annealed NWs and, focusing on the different phenomenology observed, we discuss the critical role played by NW–NW junctions on the electrical conduction and sensing performances. A mechanism is proposed to explain the high efficiency of the annealed arrays of NWs in detecting 2,4,6 trinitrotoluene vapours. This study shows the promising potential of Ge NW-based sensors in the field of civil security.
In this paper we study the impact of port activities on local employment by analyzing a sample of about 560 regions located in ten West European countries and observed over the period 2000–2006. The ...biggest European ports of OECD countries belong to our sample, which includes 116 ports. The empirical analysis is based on the estimation of a set of employment equations with the GMM-System estimator of Blundell and Bond (1998) that allows us to take into account persistence effects in employment, regional unobserved time-invariant heterogeneity, and endogeneity of port activity.
Our main findings can be summarized as follows: first, regional employment is positively correlated to port throughput, while the number of passengers is not; in second place, we found a higher impact of port throughput when the liquid bulk is considered only for 10% of its weight; third, our main results are confirmed if we consider service and manufacturing employment instead of total employment.
► The paper studies the impact of port activities on local employment. ► The paper analyses a sample of about 560 European regions, over the period 2000–2006. ► The analysis is based on a set of employment equations with the GMM-System estimator. ► Regional employment is positively correlated to port throughput. ► The distinction among service and manufacturing employment confirms the results.
Orthorhombic κ-Ga2O3 thin films were grown for the first time on polycrystalline diamond free-standing substrates by metal-organic vapor phase epitaxy at a temperature of 650 °C. Structural, ...morphological, electrical, and photoelectronic properties of the obtained heterostructures were evaluated by optical microscopy, X-ray diffraction, current-voltage measurements, and spectral photoconductivity, respectively. Results show that a very slow cooling, performed at low pressure (100 mbar) under a controlled He flow soon after the growth process, is mandatory to improve the quality of the κ-Ga2O3 epitaxial thin film, ensuring a good adhesion to the diamond substrate, an optimal morphology, and a lower density of electrically active defects. This paves the way for the future development of novel hybrid architectures for UV and ionizing radiation detection, exploiting the unique features of gallium oxide and diamond as wide-bandgap semiconductors.
In 2013 Chinese government unveiled one of the biggest transport plan schemes worldwide: the One Belt One Road (OBOR) strategy, now called the Belt and Road Initiative (BRI). This scheme includes the ...development of a group of specific transport and logistics corridors that encompass three different continents (i.e. Asia, Africa, and Europe) with both land and maritime corridors. Both these planned interventions are expected to greatly impact on the maritime transport between Far East and Northern Europe through new port investments (e.g. Piraeus, the proposed Venice container offshore terminal) and providing rail alternatives (e.g. Beijing-Hamburg rail service) that could impact on the geography of international trades. These modifications of current transport patterns might drastically change the overall organisation of the shipping services in the Mediterranean, increasing competition of transport alternatives (e.g. rail vs road; rail vs sea) and promoting the nodes included in the BRI. Thus, the current study aims at discussing effects of BRI on current maritime patterns with a specific focus on the effects into port competition within the Mediterranean area.
Background
Macrophytes may modify benthic biodiversity and biogeochemistry via radial oxygen loss from roots. This condition contrasts sediments anoxia, allows roots respiration, and facilitates ...aerobic microbial communities and processes in the rhizosphere. Simultaneously, the rhizosphere can stimulate anaerobic microorganisms and processes via exudates or by favoring the build-up of electron acceptors as nitrate. As eutrophication often results in organic enrichment in sediments and large internal nutrients recycling, an interesting research question is to investigate whether plants maintain the capacity to stimulate aerobic or anaerobic microbial communities and processes also under elevated organic pollution.
Methods
A manipulative experiment was carried out under laboratory-controlled conditions. Microcosms containing bare sediments and sediments transplanted with the macrophyte
Vallisneria spiralis
L. were created. The effect of the plant was investigated on sediments with moderate (8%) and elevated (21%) organic matter content, after an acclimatization period of 30 days. Chemical and physical parameters, microbial community composition and the potential rates of nitrification, denitrification and nitrate ammonification were measured at two different depths (0–1 and 1–5 cm) after the acclimatization period to evaluate the role of roots.
Results
Vallisneria spiralis
grew and assimilated pore water nutrients at the two organic matter levels and vegetated sediments had always nutrient-depleted porewaters as compared to bare sediments. Nitrifying microbes had a lower relative abundance and diversity compared to denitrifying bacteria. However, regardless of the organic content, in vegetated sediments nitrifiers were detected in deeper horizons as compared to bare sediments, where nitrification was confined near the surface. In contrast, potential denitrification rates were not affected by the presence of roots, but probably regulated by the presence of nitrate and by root-dependent nitrification. Potential nitrate ammonification rates were always much lower (< 3%) than potential denitrification rates.
Conclusions
Vallisneria spiralis
affects N-related microbial diversity and biogeochemistry at moderate and elevated organic matter content, smoothing bottom water–pore water chemical gradients and stimulating nitrification and nitrogen loss via denitrification. These results suggest the possibility to deploy
V. spiralis
as a nature-based solution to counteract eutrophication in freshwater systems impacted by high loads of organic matter, for example, downstream of wastewater treatment plants.
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