1,721,009 research outputs found
New improvements of the extended minimum cost flow phase unwrapping for processing multitemporal full resolution interferograms
No full textWe present an efficient space-time phase unwrapping (PhU) algorithm allowing us to analyze sequences of multitemporal full resolution differential Synthetic Aperture Radar (SAR) interferograms for the generation of deformation time-series. The core of the proposed technique is represented by the extended minimum cost flow (EMCF) PhU algorithm. Our method is based on a joint analysis of the spatial and temporal relationships among a set of properly selected multitemporal differential interferograms. More specifically, the key idea is to split the complex MCF network problem into that of simpler sub-networks. Accordingly, we start by identifying and solving a primary network that involves a proper selection of coherent pixels of the computed interferograms, representing the backbone structure of the overall network. Subsequently, this result is applied for constraining the solution of the sub-networks connected to the primary one, involving the entire set of analyzed pixels. This task is achieved by solving a constrained optimization problem based on the computation of a Constrained Delaunay Triangulation in the Azimuth/Range domain. The experimental results, achieved by applying the proposed approach to a dataset consisting of European Remote Sensing (ERS) SAR data acquired, from June 1992 to August 2007 over the Napoli (Italy) bay area, confirm the effectiveness of the proposed PhU approach
Long-term ERS/ENVISAT deformation time-series generation at full spatial resolution via the extended SBAS technique
No full textWe extend the small baseline subset (SBAS) differential synthetic aperture radar (SAR) interferometry (DInSAR) approach to allow the generation of deformation time-series by processing, at the full spatial resolution scale, long sequences of European Remote Sensing (ERS-1 and ERS-2) and Environmental Satellite (ENVISAT) SAR data acquired with the same illumination geometry. In particular, we avoid the generation of ERS/ENVISAT cross-interferograms, which are severely affected by noise phenomena due to the carrier frequency separation of the two SAR systems, and we focus on single-platform interferograms only (i.e. ERS/ERS and ENVISAT/ENVISAT interferograms) that are properly combined by applying the singular value decomposition (SVD)-based SBAS approach. Moreover, we exploit the Doppler centroid variations of the post-2000 acquisitions of the ERS-2 sensor and the carrier frequency difference between the ERS-1/2 and the ENVISAT systems, in order to maximize the number of investigated SAR pixels and to improve their geocoding. The presented results, achieved on two data sets relevant to the Napoli Bay area and to the Murge region, both located in southern Italy, confirm the effectiveness of the extended SBAS technique and demonstrate the relevance of deformation analysis carried out at the scale of single buildings or human-made structures with more than 15 years of ERS and ENVISAT acquisitions
The Extended SBAS Technique For Generating Long Term Full Resolution Ers/Envisat Deformation Time-Series
No full textThe extended SBAS technique for generating full resolution ERS/ENVISAT deformation time-series
No full textThe SBAS-DInSAR technique: A tool for deformation monitoring in the urban damage assessment
No full textNon-invasive deformation analysis of historical buildings through the advanced SBAS-DInSAR technique: the case of the city of Roma (Italy)
No full textDamage assessment through the use of SBAS-DInsar data: an application to the “Vittorino da Feltre” Masonry School building in Rome
No full textThe detection and monitoring of deformation patterns induced by causes of various nature is fundamental to prevent and mitigate the associated risk. To this aim, one of the most innovative, non-invasive monitoring approaches is based on the use of satellite radar images through the advanced multi-temporal Differential Interferometry Synthetic Aperture Radar (DInSAR) technique, which is able to detect deformations induced by slowly evolving phenomena. In this work, the multi-temporal DInSAR technique referred to as full resolution SBAS approach is exploited for the monitoring of the ground deformations and their effects on the “Vittorino da Feltre” school building located in the city of Rome (Italy), which is undergoing a retrofitting project. The displacement measurements were obtained by using the COSMO-SkyMed satellite dataset related to the city of Rome during the 2011–2019 time interval, processed with full resolution Small. The damage progression during the last years has been evaluated by comparing a recent survey of the structural damage with the previously available ones. An integration of SAR-derived data and outcomes of the on-site damage surveys is presented, aimed to perform a damage assessment of the structure using literature scales of damage
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
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