Remote Monitoring of Civil Infrastructure Based on TomoSAR

Structural health monitoring and damage detection tools are extremely important topics nowadays with the civil infrastructure aging and deteriorating problems observed in urban areas. These tasks can be done by visual inspection and by using traditional in situ methods, such as leveling or using traditional mechanical and electrical sensors, but these approaches are costly, labor-intensive and cannot be performed with a high temporal frequency. In recent years, remote sensing has proved to be a very promising methodology in evaluating the health of a structure by assessing its deformation and thermal dilation. The satellite-based Synthetic Aperture Radar Tomography (TomoSAR) technique, based on the exploitation of a stack of multi-temporal SAR images, allows to remotely sense the movement and the thermal dilation of individual structures with a centimeter-to millimeter-level accuracy, thanks to new generation high-resolution satellite-borne sensors. In this paper, the effectiveness of a recently developed TomoSAR technique in assessing both possible deformations and the thermal dilation evolution of man-made structures is shown. The results obtained using X-band SAR data in two case studies, concerning two urban structures in the city of Naples (Italy), are presented

Characteristics and coastal effects of a destructive marine storm in the Gulf of Naples (southern Italy)

Destructive marine storms bring large waves and unusually high surges of water to coastal areas, resulting in significant damages and economic loss. This study analyses the characteristics of a destructive marine storm on the strongly inhabited coastal area of Gulf of Naples, along the Italian coasts of the Tyrrhenian Sea. This is highly vulnerable to marine storms due to the accelerated relative sea level rise trend and the increased anthropogenic impact on the coastal area. The marine storm, which occurred on 28 December 2020, was analyzed through an unstructured wind-wave coupled model that takes into account the main marine weather components of the coastal setup. The model, validated with in situ data, allowed the establishment of threshold values for the most significant marine and atmospheric parameters (i.e., wind intensity and duration) beyond which an event can produce destructive effects. Finally, a first assessment of the return period of this event was evaluated using local press reports on damage to urban furniture and port infrastructures

Performance Improvement for SAR Tomography Based on Local Plane Model

Multilook approaches have been applied in synthetic aperture radar (SAR) tomography (TomoSAR), for improving the density and regularity of persistent scatterers reconstructed from multipass SAR images in both rural and urban regions. Multilook operations assume that all scatterers in a given neighborhood are similar in height, thereby providing additional data for recovering the position and reflectivity of a single scatterer, so that a higher signal-to-noise ratio can be achieved. This is equivalent to assuming that scatterers belonging to a local neighborhood of range-azimuth cells are located on horizontal planes. The present article generalizes this approach by adopting the so-called local plane (LP) model for TomoSAR imaging in urban areas, accounting for local variations in the height of scatterers that are not negligible. Furthermore, an LP-generalized likelihood ratio test (LP-GLRT) algorithm is developed to implement the previous idea. Compared with the multilook generalized likelihood ratio test algorithm, LP-GLRT shows better performance in the case of urban structures and terrains in experiments based on both simulated data and TerraSAR-X images

Influence of wind-induced effects on laser disdrometer measurements: Analysis and compensation strategies

Nowadays, laser disdrometers constitute a very appealing tool for measuring surface precipitation properties, by virtue of their capability to estimate not only the rainfall amount and intensity, but also the number, the size and the velocity of falling drops. However, disdrometric measures are affected by various sources of error being some of them related to environmental conditions. This work presents an assessment of Thies Clima laser disdrometer performance with a focus on the relationship between wind and the accuracy of the disdrometer output products. The 10-min average rainfall rate and total rainfall accumulation obtained by the disdrometer are systematically compared with the collocated measures of a standard tipping bucket rain gauge, the FAK010AA sensor, in terms of familiar statistical scores. A total of 42 rainy events, collected in a mountainous site of Southern Italy (Montevergine observatory), are used to support our analysis. The results show that the introduction of a new adaptive filtering in the disdrometric data processing can reduce the impact of sampling errors due to strong winds and heavy rain conditions. From a quantitative perspective, the novel filtering procedure improves by 8% the precipitation estimates with respect to the standard approach widely used in the literature. A deeper examination revealed that the signature of wind speed on raw velocity-diameter spectrographs gradually emerges with the rise of wind strength, thus causing a progressive increase of the wrongly allocated hydrometeors (which reaches 70% for wind speed greater than 8 m s−1). With the aid of reference rain-gauge rainfall data, we designed a second simple methodology that makes use of a correction factor to mitigate the wind-induced bias in disdrometric rainfall estimates. The resulting correction factor could be applied as an alternative to the adaptive filtering suggested by this study and may be of practical use when dealing with disdrometric data processing

Response of the Pacific Sector of the Southern Ocean to wind stress variability from 1995 to 2017

AbstractDrifter, satellite, expendable bathythermograph (XBT), and Argo float data are used to study the response of the Pacific Sector of the Southern Ocean (PSSO) to the wind stress field in the period 1995–2017, in terms of eddy field, water mass transport, and heat fluxes at large and regional scales. Increasing wind stress over the PSSO in those two decades led to a growth of the Eddy Kinetic Energy (EKE) in the region of the Antarctic Circumpolar Current (ACC). Increases of the EKE occur with delays of 1–4 years with respect to peaks in the zonal component of the wind stress. The persistent ACC meander located south of New Zealand (between 150°E and 180°W and 50°S to 66°S) responds to the interannual wind variations earlier than the entire ACC branch in the PSSO. In the same area, an estimate of the ACC transport based on in situ data shows interannual variability but no significant decadal trend over the study period. The effects of the EKE variability on the meridional eddy heat fluxes are significant on interannual scales. The strengthening of the EKE field leads to a local increase in the poleward meridional eddy heat fluxes in the PSSO, especially in the ACC band. The weakening of the EKE field defines an area of equatorward meridional eddy heat fluxes in the middle of the PSSO (south of 40°S, between 130°W and 160°W) and prevalent poleward fluxes in the further western and eastern regions

Image sensors for wave monitoring in shore protection: Characterization through a machine learning algorithm

Waves propagating on the water surface can be considered as propagating in a dispersive medium, where gravity and surface tension at the air–water interface act as restoring forces. The velocity at which energy is transported in water waves is defined by the group velocity. The paper reports the use of video‐camera observations to study the impact of water waves on an urban shore. The video‐monitoring system consists of two separate cameras equipped with progressive RGB CMOS sensors that allow 1080p HDTV video recording. The sensing system delivers video signals that are processed by a machine learning technique. The scope of the research is to identify features of water waves that cannot be normally observed. First, a conventional modelling was performed using data delivered by image sensors together with additional data such as temperature, and wind speed, measured with dedicated sensors. Stealth waves are detected, as are the inverting phenomena encompassed in waves. This latter phenomenon can be detected only through machine learning. This double approach allows us to prevent extreme events that can take place in offshore and onshore areas

Anticancer drugs and hyperthermia enhance cytotoxicity induced by polyamine enzymatic oxidation products

A correlation between regulation of cell proliferation and polyamine metabolism is described. The latter can enter protein synthesis through the modification of eukaryotic initiation factor 5A (eIF5A) and the formation of the peculiar amino acid hypusine. Specific inhibitors of hypusine formation induce apoptosis that can be potentiated by the combination with cytokines such as interferon alpha (IFN alpha) that itself decreases hypusine synthesis. We have also demonstrated that the concomitant treatment of cancer cells with IFNa and the protein synthesis inhibitor fusion protein TGF alpha/Pseudomonas Aeruginosa toxin synergize in inducing cancer cell growth inhibition. Another way used by polyamines to induce apoptosis is the generation of intracellular oxidative stress through the interaction with bovine serum amine oxidase (BSAO). This enzyme used simultaneously to spermine induces apoptosis, necrosis, inhibition of cell proliferation and inhibition of DNA and protein synthesis in several cell types. The enzymatic oxidation products of polyamine, H2O2 and aldehyde(s) cause these effects. We have recently found that the cytotoxicity of anti-cancer agents, either etoposide or docetaxel, in cancer cells is potentiated in the presence of BSAO/Spermine. In conclusion, polyamine metabolites could be useful in the design of new therapeutic strategies

URBAN MONITORING BASED ON SENTINEL-1 DATA USING PERMANENT SCATTERER INTERFEROMETRY AND SAR TOMOGRAPHY

A lot of research and development has been devoted to the exploitation of satellite SAR images for deformation measurement and monitoring purposes since Differential Interferometric Synthetic Apertura Radar (InSAR) was first described in 1989. In this work, we consider two main classes of advanced DInSAR techniques: Persistent Scatterer Interferometry and Tomographic SAR. Both techniques make use of multiple SAR images acquired over the same site and advanced procedures to separate the deformation component from the other phase components, such as the residual topographic component, the atmospheric component, the thermal expansion component and the phase noise. TomoSAR offers the advantage of detecting either single scatterers presenting stable proprieties over time (Persistent Scatterers) and multiple scatterers interfering within the same range-azimuth resolution cell, a significant improvement for urban areas monitoring. This paper addresses a preliminary inter-comparison of the results of both techniques, for a test site located in the metropolitan area of Barcelona (Spain), where interferometric Sentinel-1 data were analysed

A liver angioma colonized by colon cancer cells in a patient with two primitive localizations by colon adenocarcinoma: biologic, diagnostic and therapeutic implications

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