Search results for "Geotechnical engineering"
showing 10 items of 489 documents
Drones - New technologies for geophysics?
2015
Drones, also referred as Unmanned Aircraft Systems (UAS), Unmanned Aerial Vehicles (UAV) or Remotely Piloted Aircraft (RPA), are aircraft without pilot on board. USA is today the leading country in the field of UAS but recently, seven European countries have pledged to launch joint programs for drones, with the aim of producing the next generation of UAS before 2020. According to some studies on the potential market of UAS in Europe, the geoscience sector is definitely one of the most promising. In this paper, we bring a short description and classification of drones, according to their sized and shaped, with particular attention to the advantages and drawbacks of each type in reference to …
Uncertainty in urban flood damage assessment due to urban drainage modelling and depth-damage curve estimation
2010
Due to the increased occurrence of flooding events in urban areas, many procedures for flood damage quantification have been defined in recent decades. The lack of large databases in most cases is overcome by combining the output of urban drainage models and damage curves linking flooding to expected damage. The application of advanced hydraulic models as diagnostic, design and decision-making support tools has become a standard practice in hydraulic research and application. Flooding damage functions are usually evaluated by a priori estimation of potential damage (based on the value of exposed goods) or by interpolating real damage data (recorded during historical flooding events). Hydrau…
Nature and origin of fault-controlled fluid seepage across the Maltese Islands
2018
The Maltese Islands are intersected by two major fault systems associated with two diverse rifting episodes affect the islands. The first and most widespread system is Early Miocene to mid-Pliocene in age, and consists of faults that are orientated ENE-WSW. The most distinct of these faults is the Great Fault (known also as the Victoria Lines Fault). The younger system of faults (Late Miocene-Early Pliocene) is still active and consists of faults striking NW to SE that often cross-cut the first generation of faults. The most extensive of these faults is the Maghlaq Fault, located along the southern coastline of the Maltese Islands.
Measuring Field Rill Erodibility by a Simplified Method
2015
Many process-oriented erosion prediction models reproduce rill erosion as affected by site-specific parameters, as for example, rill erodibility, and thus, their practical application requires the measurement of these parameters or their estimate. The aim of this paper was establishing a method for indirectly measuring field rill erodibility. A simple mathematical approach based on a known soil detachment equation and accounting for the rill erosion dynamic process is applied. Field measurements carried out for seven natural rainfall events occurring at the plots of the Sparacia experimental station, southern Italy, are used for indirectly measuring the rill erodibility of the investigated …
The reaction structure of the LEDA research centre: Development and design
2017
In the last twenty years, the field of earthquake engineering experienced a noticeable improvement. The results of experimental and theoretical researches have contributed to the development of modern technical codes, which provide innovative solutions for the structural assessment and new design approaches. Despite this large amount of improvements, several open questions are still open, and the need for large scale testing has been deeply proved and discussed. A new research facility, namely the Laboratory of Earthquake engineering and Dynamic Analysis (LEDA), has been recently completed at the University of Enna "Kore". This research centre, funded with a grant from Italian Ministry of E…
Outgassing: Influence on speed of magma fragmentation
2013
[1] Predicting explosive eruptions remains an outstanding challenge. Knowledge of the controlling parameters and their relative importance is crucial to deepen our understanding of conduit flow dynamics and accurately model the processes involved. This experimental study sheds light on one important parameter—outgassing—and evaluates its influence on magma fragmentation behavior. We perform fragmentation experiments based on the shock tube theory at room temperature on natural pyroclastic material with a connected porosity ranging from 15% to 78%. For each sample series, we determine the initial pressure (P) required to initiate magma fragmentation (fragmentation threshold, Pth). Furthermor…
Efficient Nonlinear RX Anomaly Detectors
2020
Current anomaly detection algorithms are typically challenged by either accuracy or efficiency. More accurate nonlinear detectors are typically slow and not scalable. In this letter, we propose two families of techniques to improve the efficiency of the standard kernel Reed-Xiaoli (RX) method for anomaly detection by approximating the kernel function with either {\em data-independent} random Fourier features or {\em data-dependent} basis with the Nystr\"om approach. We compare all methods for both real multi- and hyperspectral images. We show that the proposed efficient methods have a lower computational cost and they perform similar (or outperform) the standard kernel RX algorithm thanks t…
Accounting for Input Noise in Gaussian Process Parameter Retrieval
2020
Gaussian processes (GPs) are a class of Kernel methods that have shown to be very useful in geoscience and remote sensing applications for parameter retrieval, model inversion, and emulation. They are widely used because they are simple, flexible, and provide accurate estimates. GPs are based on a Bayesian statistical framework which provides a posterior probability function for each estimation. Therefore, besides the usual prediction (given in this case by the mean function), GPs come equipped with the possibility to obtain a predictive variance (i.e., error bars, confidence intervals) for each prediction. Unfortunately, the GP formulation usually assumes that there is no noise in the inpu…
Warped Gaussian Processes in Remote Sensing Parameter Estimation and Causal Inference
2018
This letter introduces warped Gaussian process (WGP) regression in remote sensing applications. WGP models output observations as a parametric nonlinear transformation of a GP. The parameters of such a prior model are then learned via standard maximum likelihood. We show the good performance of the proposed model for the estimation of oceanic chlorophyll content from multispectral data, vegetation parameters (chlorophyll, leaf area index, and fractional vegetation cover) from hyperspectral data, and in the detection of the causal direction in a collection of 28 bivariate geoscience and remote sensing causal problems. The model consistently performs better than the standard GP and the more a…
Effect of FRP strengthening on the flexural behaviour of calcarenite masonry walls
2017
The use of fiber-reinforced polymers (FRP) for structural strengthening has become increasingly popular in recent years. Several applications of FRP have been proposed and applied, depending on the target of the technique, kind and/or material of the structural member. In particular, because of their great tensile strength, FRP materials are commonly used to enhance the out-of-plane behaviour of masonry walls, allowing to increase their strength, ductility and improving safety against overturning. For these reasons, FRP laminates are often applied in vulnerable ancient buildings in seismic areas to reinforce façades and walls with poor structural features. However, some issues arise when a…