In this paper, an efficient method is proposed for constructing the seismic fragility curves of bridge piers, in which the dynamical reliability assessment is developed from methods of moment. The main procedure for constructing seismic fragility curves consists of four steps. First, the non-stationary seismic acceleration process samples are simulated by the random function-spectrum representation

The traveling wave resonance phenomenon exhibits in the seismic response of the symmetric bridge structure. However, there is a scarcity of shaking table tests validating the traveling wave resonance. A 1/70-scale pile-soil-cable-stayed bridge model was fabricated following the preliminary design of a cable-stayed bridge with a main span of 1400 m. Shaking table tests were performed to verify the traveling

Nonlinear site response modeling is a crucial aspect of Probabilistic Seismic Hazard Analysis. Site amplification models routinely rely on a rock intensity measure to characterize the strength of the bedrock motion. However, the adequacy of such intensity measures towards predicting amplifications across the oscillator period range has not been investigated in the literature. This paper analyzes the

Owing to the good strength and stability of loess under dry and static conditions, many buildings in loess areas are built on slopes in western China, i.e., an earthquake-prone area. A phenomenon was discovered in the Minxian-Zhangxian Ms 6.6 earthquake and Jiuzhaigou Ms 7.0 earthquake, that is, the damage to the buildings on the top of the slope was more serious than that on the horizontal site, and

The high-energy rate of shock waves, as an important part of explosion energy, plays a significant role in the mechanism of rock fragmentation. This energy rate and the mechanism of rock fracturing are controlled by several parameters related to both the explosive charge and rock mechanical properties. In this study, the mechanism of rock fragmentation due to blast-induced shock waves in a single blasthole

This study investigates the evidence of shallow gas from a newly collected dataset comprising 2D multi-channel seismic (MCS), single-channel seismic (SCS), Chirp sub-bottom profiler (SBP), and multi-beam echo sounder (MBES) data from the southwestern continental shelf of the Ulleung Basin, East Sea, Korea. Various indicators of shallow gas were identified in this part the shelf, including seismic chimneys

The 1800 Ma monzonitic to syenitic Raftsund intrusion is the largest intrusive body of the Lofoten-Vesterålen AMCG (anorthosite-mangerite-charnockite-granite) suite. It is composed of three units that can be differentiated based on their textures. This study focuses on the most voluminous, predominately equigranular, unit consisting of a pigeonite-augite syenite and a fayalite-augite monzonite. The

The effects of supercritical CO2 (scCO2) on coal pores play a critical role in the geological storage of CO2 and enhanced coalbed methane recovery (CO2-ECBM). To investigate the effects of scCO2 - H2O on the mesopore - macropore structure of high-rank coals, a series of experimental simulations and analyses were performed. Coal samples from the Qinshui Basin, China were exposed to scCO2 and deionized

The active earth pressure evaluation was typically conducted assuming dry backfills and/or two-dimensional collapse mechanisms. In practice, retained slope collapse usually shows a three-dimensional (3D) feature and soils are usually unsaturated. The present work develops a framework for evaluating the 3D active earth pressure under transient unsaturated flow conditions. The framework is implemented

The characteristics of coal deposits are relatively homogeneous in general; therefore, their geometric and quality parameters have stationary distributions. However, the geological setting could change this stationarity characteristic; thus, the coal may contain spatially different data trends. These data trends should be treated to derive an accurate estimation of the available coal resources. The

The NNW-SSE trending Teruel Basin rift is the largest Late Miocene-Quaternary extensional intracontinental structure located within the central-eastern Iberian Chain (Spain). The structural and morphotectonic study carried out in the central-northern part of this half graben basin (north of Teruel city) has allowed us to analyse rift segmentation, deformation partitioning and rift evolution. Results

Auto-extraction of convective clouds is of great significance. Convective clouds often bring heavy rain, strong winds, and other disastrous weather. Early warning of convection can effectively reduce loss. Using remote sensing images, we can get large-scale cloud information, which provides many effective methods for convective clouds detection. In this letter, we proposed a novel method to extract

Sea surface temperature (SST) significantly affects the processes of air–sea interactions, and, thus, forms an important indicator of climate changes. In SST predictions, the approach of artificial neural networks (ANNs) is data-driven, unlike that of the numerical models, which are physics-based. In this letter, Operational SST and Ice Analysis (OSTIA) data set were used for training ANN models and

The leaf area index (LAI) is a crucial parameter that governs the physical and biophysical processes of plant canopies and acts as an input variable in land surface and soil moisture modeling. The ScatSat-1 is the latest microwave Ku-band scatterometer mission of Indian Space Research Organization (ISRO), provides data at a higher temporal and spatial resolution for various applications. Due to its

In most cases, reservoir properties at one certain depth in the layer can be explicated by logging signals at just this depth point. In fact, the properties of complex reservoirs are often implicated in logging signals from the whole adjacent region of this certain depth point. So far, there is no effective way to solve this problem completely. For the first time, this letter tried to build a fully

Land surface temperature (LST) and its diurnal variation are the critical factors in many aspects of climate study, surface energy balance, and environmental applications. Several satellite-based LST products are available for retrievals from regional to a global scale. However, due to the differences in sensor configurations and retrieval algorithms, these products may not necessarily be consistent

We present a 2.5-D finite difference (FD) algorithm to simulate the logging-while-drilling (LWD) electromagnetic (EM) measurements with arbitrarily oriented magnetic dipole sources in 2-D anisotropic media. The real 3-D modeling in the spatial domain is converted to a series of independent 2-D equations in the spectral domain by implementing the Fourier transform (FT). By replacing the dipoles with

This letter presents the joint reconstruction of unknown subsurface structures by the full-wave inversion (FWI) and reverse time migration (RTM) imaging. In the FWI, the 1-D distorted Born iteration method (DBIM) is employed to retrieve the dielectric parameters of the layered subsurface medium by minimizing the difference between measured fields and calculated fields via Fréchet derivatives. Based

This letter analyzes the background signals and thermal noise received over ocean scenes in spaceborne global navigation satellite system (GNSS)-reflectometry (GNSS-R) remote sensing using observations from the cyclone GNSS (CYGNSS) constellation. The measured noise floor contains a stable and predictable radiometric thermal noise component and a more variable background signal component from unintended

We explore the use of convolutional neural networks (CNNs) for filling voids in digital elevation models (DEM). We propose a baseline approach using a fully convolutional network to predict complete from incomplete DEMs, which is trained in a supervised fashion. We then extend this to a shadow-constrained CNN (SCCNN) by introducing additional loss functions that encourage the restored DEM to adhere

S4 index is the rapid modification of signals when propagating through small-scale structures in the ionosphere, called ionospheric irregularities. The rapid modification of the signal causes the scintillation of the power. The purpose of this letter is to confirm the superposition property of the S4 index by using the ray-tracing method to simulate the signal propagation path through the ionospheric

Precipitation nowcasting is an important task in operational weather forecasts. The key challenge of the task is the radar echo map extrapolation. The problem is mainly solved by an optical-flow method in existing systems. However, the method cannot model rapid and nonlinear movements. Recently, a convolutional gated recurrent unit (ConvGRU) method is developed, which aims to model such movements based

Sky-wave over-the-horizon radar (OTHR) systems are of particular interest to the Canadian Department of National Defence (DND) since they provide the potential for surveillance of Canada. Because of dynamic ionospheric conditions in polar regions, any OTHR would necessitate a system where the operating frequencies and elevation angles change periodically to maintain constant detection of targets downrange

Deep neural networks have shown promise in the radar-based human activity analysis application. Different from existing deep learning models that take either micro-Doppler spectrograms or range profiles as their input, the proposed method can process micromotion signatures in a 3-D way. In this letter, we first transform radar echoes into range-Doppler (RD) time points and then directly process the

Due to multipath (MP) scattering, many special phenomena and details about the targets in high-resolution synthetic aperture radar (SAR) images are hard to understand. In this letter, a more elaborate improved model combined with the synthetic aperture progress is presented, to analyze the MP scattering. We explore the defocusing and displacement phenomena of MP scattering through signal modeling and

The spaceborne stripmap range sweep synthetic aperture radar (SAR) (SS-RSSAR) is a new-concept SAR mode proposed to efficiently image regions of interest (ROI) squinted with respect to satellite orbit. The most distinct feature of the SS-RSSAR is the beam sweeping in the elevation for continuous squinted ROI illumination. A wide nonlinear chirp scaling algorithm (WNLCSA) has been proposed to directly

Differential synthetic aperture radar tomography (D-TomoSAR) has proven an effective method for retrieving the elevations and deformations of both terrains and urban infrastructures. Particularly, D-TomoSAR with high-resolution X-band SAR data provides even higher accuracy for monitoring of deformations of the man-made structures. However, higher frequency increases the sensitivity of the system to

By introducing curvilinear structures extraction (CSE) instead of watershed algorithm (WA) or nonmaximum suppression (NMS) to edge strength map (ESM), an improved ratio of exponentially weighted averages (ROEWA) edge detector with better capacity for weak edges detection is proposed to extract smooth edges and edge direction of synthetic aperture radar (SAR) images. Using the ROEWA, the ESM is calculated

Displaced phase center array (DPCA) and along-track interferometry (ATI) have been widely used for ground moving target indication (GMTI) in multi-channel circular synthetic aperture radar (CSAR) system. In ideal conditions, these methods can suppress background clutter effectively. However, the nonideal movement of platform may create a nonzero crab angle, which will induce a cross-track baseline

This letter proposes a new synthetic aperture radar (SAR) image building detection method based on the bi-dimensional empirical mode decomposition (BEMD) algorithm, well adapted to nonlinear and nonstationary signals. First, the SAR image is decomposed by the BEMD algorithm to generate intrinsic mode functions (IMFs), and the IMFs are combined to extract bright regions and dark regions from the SAR

In multi-channel synthetic aperture radar-ground moving target indication (SAR-GMTI), most radial velocity estimation methods are based on the phase difference between channels. However, the image coregistration and channel phase errors will have a severe impact on the phase difference between channels. Moreover, it deteriorates the performance of the moving target radial velocity estimation. To solve

Pan-sharpening aims to fuse a low-spatial-resolution multispectral (MS) image with an associated higher resolution panchromatic image (PAN) in order to produce a high-resolution MS (HRMS) image to overcome physical limitation of satellite sensors. In this letter, we propose a new generalized Laplacian pyramid gain injection prediction based on convolutional neural networks (GIP-CNN) for pan-sharpening

Observation of the Earth using satellites mounted with optical sensors is an important application of remote sensing. Owing to physical constraints, multispectral (MS) sensors acquire images of lower spatial resolution than a single-band panchromatic (PAN) sensor that acquires images of the same scene. Pansharpening fuses the MS and PAN images to obtain an MS image with the same spatial resolution

Hyperspectral anomaly detection is a hot topic in remote sensing applications. Most of the conventional detectors are based on the Reed–Xiaoli (RX) method and assumedly targets and backgrounds follow a Gaussian distribution in which two problems exist: the outliers in the Gaussian distribution statistics limit the detection accuracy of RX method, and the larger proportions between the backgrounds and

To fuse hyperspectral and Light Detection And Ranging (LiDAR), we propose a semisupervised graph fusion (SSGF) approach. We apply morphological filters to LiDAR and the first few components of hyperspectral data to model the height and spatial information, respectively. Then, the proposed SSGF is used to project the spectral, elevation, and spatial features onto a lower subspace to obtain the new features

A novel hyperspectral image (HSI) classification method based on joint collaborative representation with shape adaptive region and locally adaptive dictionary (SALJCR) is proposed in this letter. First, the shape adaptive (SA) region is selected for each pixel to exploit the neighboring spatial information adaptively. The average filtering (according to SA regions) is performed for the whole image

Owing to the relatively small size of vehicles in remote sensing images, lacking sufficient detailed appearance to distinguish vehicles from similar objects, the detection performance is still far from satisfactory compared with the detection results on everyday images. Inspired by the positive effects of super-resolution convolutional neural network (SRCNN) for object detection and the stunning success

The spatial resolution of remote sensing images is continuously improved by the development of remote sensing satellite and sensor technology. Hence, background information in an image becomes increasingly complex and causes considerable interference to the object detection task. Can we pay as much attention to the object in an image as human vision does? This letter proposes a multi-scale spatial

Water-body segmentation in high-resolution satellite imagery is challenging because of the significant variations in the appearance, size, and shape of water bodies. In this letter, a novel multiscale refinement network (MSR-Net) is proposed for water-body segmentation. Similar to most learning-based methods, the MSR-Net resorts to the multiscale information for segmentation, but it improves existing

In the optical remote sensing and earth observation fields, clouds severely obscure the land’s visibility and degrade the image. In recent years, there have been many excellent efforts to mitigate the effects of cloud cover. However, it has been found that there will be some blurs in the area if a single degraded image is restored by autoencoder-based methods. This letter focuses on removing clouds

To better reveal time-varying spectral components of nonstationary seismic signals, time–frequency analysis (TFA) has been widely applied in seismic processing and analysis. In this letter, we propose an advanced seismic TFA method based on an optimal spectral mode separation and an adaptive wavelet bank design. The proposed adaptive mode separation-based wavelet transform (AMSWT) generates a superior

In seismic exploration, random noise is an obstacle to the extraction of the effective signals, so the investigation aimed at random noise is the basis of signal processing. It is of great significance to analyze the noise properties and establish accurate noise models. Since the complex changes of the actual medium seriously affect propagation characteristics, it is necessary to establish a noise

Subsurface scatters are sometimes masked by reflectors in seismic migration images, because the diffractions are much weaker in energy than the reflections. We propose a novel imaging method, named reflection-damped plane-wave least-squares reverse time migration (RD_PLSRTM), to enhance the scatters in the migration image. We formulate seismic imaging as an inverse problem that minimizes a weighted

Time–frequency (TF) analysis algorithms are widely used to process seismic data. Unfortunately, most TF analysis algorithms cannot process 2-D seismic data, which contain more information than 1-D data. In fact, 2-D $x$ – $t$ domain seismic data should be analyzed in the multi-dimensional phase space (MDPS). In this letter, we develop and explain an MDPS analysis method for 2-D seismic data. In order

Representation-based target detectors for hyperspectral imagery (HSI) have recently aroused a lot of interests. However, existing methods ignore the dictionary structure and cannot guarantee an informative and discriminative representation of test pixels for target detection. To alleviate the problem, this letter proposes a novel sparse and dense hybrid representation-based target detector (SDRD).

The semantic interpretation using point clouds, especially regarding light detection and ranging (LiDAR) point cloud classification, has attracted a growing interest in the fields of photogrammetry, remote sensing, and computer vision. In this letter, we aim at tackling a general and typical feature learning problem in 3-D point cloud classification— how to represent geometric features by structurally

High pressure phase relations for much of the Cu-Fe-S system have not previously been determined experimentally. Experimental studies have concentrated on low-pressure phase relations and cannot explain high pressure sulfide mineral inclusion assemblages in some natural blueschists and eclogites. In particular, the co-existence of pyrite + covellite at 1.0 GPa, and pyrite + bornite at 1.9 GPa, observed

Pre-existing joints have a significant influence on the geometry of the fracture network induced by hydraulic fracturing. Understanding the interaction between hydraulic fractures (HF) and pre-existing joints is of great importance to optimize the design of hydraulic fracturing operations in many applications. A three-dimensional hydro-mechanical coupled lattice-spring code was employed to investigate

The Cretaceous Yunshan caldera complex in SE China consists of an unusual coexisting assemblage of peraluminous and peralkaline rhyolites and a resurgent intra-caldera porphyritic quartz monzonite. In this study, we use zircon trace element data to study the compositional differences of zircons from cogenetic magmas and to track the evolution of the entire magmatic system. Our results indicate that

Alteration of oceanic lithosphere plays an important role in the global element cycling due to its dominant abundance on the Earth's surface. The formation of rodingites, a Ca rich lithology that occurs intimately associated with Ca depleted serpentinite complexes, is a widespread process during strong alteration of ocean-floor lithologies and may represent a key process that influences the global

This paper presents a study on mitigating the degradation of ballast by placing an under-sleeper rubber pad (USP) beneath a sleeper. Large-scale track process simulation apparatus (TPSA) tests have been carried out on ballast assemblies (with and without USP) subjected to cyclic loadings. Numerical modelling has been performed using a coupled discrete-continuum modelling (coupled DEM-FDM) approach

A stability analysis of slurry-supported trenches in horizontally layered cohesive-frictional soils by using the kinematical approach of limit analysis is presented. To ensure the kinematical admissibility, the failure surface in the formulated multi-block rotational mechanism was composed of several segments of logarithmic spirals with a same rotation center. To account for varying soil properties

Bacteria are ubiquitous in all depositional environments, especially in marine environments where anoxic/euxinic conditions prevail. In such environments, sulfate-reducing bacteria play a critical role to supply sulfur as a biogenic source for H2S through biomass degradation. In the biodegradation process, chemical and mechanical properties of the organic matter alter. In order to document these variations

The late Neogene marls from the Lorca, Murcia and Vera basins in S-E. Spain contains abundant dolomite nodules that were formed due to intense methane-rich fluid migration. The pathways for these fluids are evidenced by dense networks of fractures that are crossing the sedimentary layers and eventually the dolomite nodules. The fractures are generally filled by secondary fibrous gypsum that form veins

Geochemistry of volatiles in active volcanoes provides insights into the magmatic processes and evolution at depth, such as magma evolution and degassing, which can be implemented into volcanic hazards assessment. Deception Island is one of the most active volcanoes in Antarctica, with more than twenty explosive eruptions documented over the past two centuries. Hydrogen and oxygen isotopic variations

Analytical methods based on linear elasticity have been used to model the dynamic response of foundations. These solutions commonly assume that soils are isotropic and elastic. Incorporation of anisotropy and the two-phased nature of soils (solid skeleton with pores filled with water) is important in the study of dynamic response of foundations. This paper presents the explicit analytical solutions

The aim of this article was to optimize the shape and modulus of T-shaped deep cement mixing (TDM) and conventional deep cement mixing (DCM) columns for supporting embankment over soft soil. Objective of optimization is minimizing the column costs and differential settlement while maximizing the stress efficacy. A 2D axisymmetric numerical modelling was employed to investigate the behavior of TDM and

Coal ash is one of the largest industrial waste streams in the United States and contains elevated concentrations of hazardous elements that could pose environmental and human health risks. Due to the relatively high strontium concentrations in coal ash and the distinctive 87Sr/86Sr ratios, Sr isotopes have been utilized to trace coal ash contaminants in impacted water resources. While previous studies

A “permeability equilibration time” is typically assumed in interpreting permeability measurements – indicating that equilibration has been reached and both sorption-induced changes in deformation and their impact on permeability evolution have ceased. However, for extremely low matrix permeability (tight) dual porosity rocks, this “permeability equilibration time” may easily exceed the time interval