1,721,080 research outputs found
Knowledge distillation for efficient standard scanplane detection of fetal ultrasound
No full textAbstract: In clinical practice, ultrasound standard planes (SPs) selection is experience-dependent and it suffers from inter-observer and intra-observer variability. Automatic recognition of SPs can help improve the quality of examinations and make the evaluations more objective. In this paper, we propose a method for the automatic identification of SPs, to be installed onboard a portable ultrasound system with limited computational power. The deep Learning methodology we design is based on the concept of Knowledge Distillation, transferring knowledge from a large and well-performing teacher to a smaller student architecture. To this purpose, we evaluate a set of different potential teachers and students, as well as alternative knowledge distillation techniques, to balance a trade-off between performances and architectural complexity. We report a thorough analysis of fetal ultrasound data, focusing on a benchmark dataset, to the best of our knowledge the only one available to date. Graphical abstract: [Figure not available: see fulltext.]
Monitoring saltwater intrusion in the area surrounding the Grado lagoon (NE Italy)
No full textCoastal aquifers are heavily influenced by seawater intrusion, a phenomenon exacerbated by current climate change, which is affecting the availability of freshwater for drinking and irrigation purposes. This occurrence also leads to a progressive salinization of agricultural lands, adversely affecting crop yields. Despite the importance of groundwater salinization management for coastal agriculture in the Friuli Venezia Giulia region (NE Italy), there is currently a lack of detailed study on the topic. To partly fill this gap, a first field campaign was carried out in the inland areas surrounding the Grado lagoon, as part of an ongoing PhD project focusing on the regional issue. The Grado lagoon is a low energy environment characterized by higher salinity compared to the Adriatic Sea and the nearby Marano lagoon, due to shallower depth and limited presence of freshwater tributaries. In the inland regions of the Grado lagoon, which are mainly situated below sea level and predominantly utilized for agriculture, ensuring environmental sustainability rely heavily upon effective water resource management. In order to tackle this challenge and manage the water resource effectively, it is crucial to establish a comprehensive hydrogeological model of the area. Non-invasive geophysical investigation techniques have commonly been employed for this purpose in similar contexts. In this study, Electromagnetic induction (EMI) technique has been utilized for studying saline intrusion in the subsurface, thanks to its ability to explore large areas in relatively short times, detecting depth and lateral variations in electrical conductivity which can be associated with soil salinity changes. During this campaign, more than 30 km electrical conductivity profiles were collected along the lagoon margin, highlighting electrical conductivity variations, directly linked to the presence of saltwater in the aquifers closer to the saltwater body. The data obtained from EMI surveys were validated through Electrical Resistivity Tomography profiles performed in selected location and through direct sampling of groundwater, conducted via manual boreholes drilled to varying depths relatively to the groundwater level. The material retrieved from the drillings also enabled us to obtain short stratigraphic logs, which have contributed to a better understanding of the salinity distribution in the coastal aquifers. The combined approach has demonstrated its worth by providing crucial insights into the extent of salinization in the coastal phreatic aquifers. A thorough understanding of seawater intrusion is essential for future strategic planning of water resource management and agricultural development in the study area
Comparison of electrical resistivity tomography and frequency domain electromagnetic methods for mapping seawater intrusion in shallow aquifers -
No full textSeawater intrusion into coastal aquifers is an increasingly critical global issue, exacerbated by climate change, rising sea levels, and overexploitation of groundwater. Effective monitoring and assessment tools are crucial to ensure the long-term sustainability of freshwater resources. While conventional hydrogeological techniques such as borehole logging and Electrical Resistivity Tomography (ERT) provide detailed subsurface data, they are often constrained by limited spatial coverage and labor-intensive acquisition due to the need for direct ground contact. This study explores the use of Frequency Domain Electromagnetic (FDEM) methods as a rapid, non-invasive alternative for identifying shallow seawater intrusion. Field measurements were carried out at four distinct coastal sites in the Friuli Venezia Giulia region (N-E Italy), each presenting unique salinity gradients, geological settings, and seasonal variations. Two FDEM instruments were tested: a multioffset, constant-frequency device and a single-offset, multi-frequency system, both selected for their ability to efficiently acquire broad, spatially continuous datasets. ERT was used as the reference technique for evaluating subsurface conductivity. Apparent electrical conductivity (ECa) values from FDEM surveys were normalized and statistically compared with ERT-derived data to assess accuracy and correlation. Although differences in absolute conductivity values were observed between the FDEM devices and the ERT profiles, the overall spatial trends in salinity distribution were consistent. Statistical calibration via cross-plot analysis significantly improved data alignment, though the effectiveness of such remained site- and season-dependent. The results demonstrate that, when appropriately calibrated, FDEM systems can reliably map shallow salinity distributions and are well-suited for extended survey areas and three-dimensional investigations. While ERT continues to serve as a powerful tool for localized, high-resolution studies, FDEM offers a faster and more practical solution for large-scale monitoring. Furthermore, this calibration approach is adaptable to a wide range of geological and environmental applications beyond hydrogeological studies. In summary, the integration of ERT and FDEM methods advances our capacity to monitor coastal aquifer salinization and supports the design of efficient, wide-area assessment strategies essential for sustainable groundwater management in at-risk coastal environments
La carta della vulnerabilità intrinseca ed integrata alla contaminazione per l'area carsica del Monte Covria (Friuli , Italia)
No full textL'area del monte Covria è caratterizzata dalla presenza di differenti formazioni a grado di carsivicabilità differente.
All'interno di alcune di esse sono presenti ampli sistemi carsici che alimentano acquedotti degli agglomerati urbani di fondovalle.
L'area è stata studiata utilizzando il metodo SINTACS per realizzarene la carta di vulnerabilità intrinseca ed integrata
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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