Synthetic Maps Research Articles

Liquefaction and Related Ground Failure from July 2019 Ridgecrest Earthquake Sequence

ABSTRACT The 2019 Ridgecrest earthquake sequence produced a 4 July M 6.5 foreshock and a 5 July M 7.1 mainshock, along with 23 events with magnitudes greater than 4.5 in the 24 hr period following the mainshock. The epicenters of the two principal events were located in the Indian Wells Valley, northwest of Searles Valley near the towns of Ridgecrest, Trona, and Argus. We describe observed liquefaction manifestations including sand boils, fissures, and lateral spreading features, as well as proximate non-ground failure zones that resulted from the sequence. Expanding upon results initially presented in a report of the Geotechnical Extreme Events Reconnaissance Association, we synthesize results of field mapping, aerial imagery, and inferences of ground deformations from Synthetic Aperture Radar-based damage proxy maps (DPMs). We document incidents of liquefaction, settlement, and lateral spreading in the Naval Air Weapons Station China Lake US military base and compare locations of these observations to pre- and postevent mapping of liquefaction hazards. We describe liquefaction and ground-failure features in Trona and Argus, which produced lateral deformations and impacts on several single-story masonry and wood frame buildings. Detailed maps showing zones with and without ground failure are provided for these towns, along with mapped ground deformations along transects. Finally, we describe incidents of massive liquefaction with related ground failures and proximate areas of similar geologic origin without ground failure in the Searles Lakebed. Observations in this region are consistent with surface change predicted by the DPM. In the same region, geospatial liquefaction hazard maps are effective at identifying broad percentages of land with liquefaction-related damage. We anticipate that data presented in this article will be useful for future liquefaction susceptibility, triggering, and consequence studies being undertaken as part of the Next Generation Liquefaction project.

Phase noise reduction in wavelength scanning interferometry using a phase synthesis approach

We proposed a method to reduce the phase noise in wavelength scanning interferometry (WSI). The method utilizes the two different mechanisms of Fourier transform and the least squares algorithm to produce a synthetic phase map. For validation, the deformation of a fiberglass reinforced resin matrix composite specimen under mechanical loading was measured using a self-built WSI system. The results demonstrate the decrease of phase noise points by more than 20% without sacrificing spatial resolution. The reduction of phase noise can provide high quality phase unwrapping and increase the accuracy of deformation measurements.

Salient object detection for RGB-D images by generative adversarial network

Salient object detection for RGB-D image aims to automatically detect the objects of human interest by color and depth information. In the paper generative adversarial network is adopted to improve its performance by adversarial learning. Generator network takes RGB-D images as inputs and outputs synthetic saliency maps. It adopts double stream network to extract color and depth feature individually and then fuses them from deep to shallow progressively. Discriminator network takes RGB image and synthetic saliency maps (RGBS), RGB image and ground truth saliency map (RGBY) as inputs, and outputs their labels indicating whether input is synthetics or ground truth. It consists of three convolution blocks and three fully connected layers. In order to pursuit long-range dependency of feature, self-attention layer is inserted in both generator and discriminator network. Supervised by real labels and ground truth saliency map, discriminator network and generator network are adversarial trained to make generator network cheat discriminator network successfully and discriminator network distinguish synthetics or ground truth correctly. Experiments demonstrate adversarial learning enhances the ability of generator network, RGBS and RGBY input in discriminator network and self-attention layer play an important role in improving the performance. Meanwhile our method outperforms state-of-the-art methods.

Linear dust polarization during the embedded phase of protostar formation

Context. Measuring polarization from thermal dust emission can provide important constraints on the magnetic field structure around embedded protostars. However, interpreting the observations is challenging without models that consistently account for both the complexity of the turbulent protostellar birth environment and polarization mechanisms. Aims. We aim to provide a better understanding of dust polarization maps of embedded protostars with a focus on bridge-like structures such as the structure observed toward the protostellar multiple system IRAS 16293–2422 by comparing synthetic polarization maps of thermal reemission with recent observations. Methods. We analyzed the magnetic field morphology and properties associated with the formation of a protostellar multiple based on ideal magnetohydrodynamic 3D zoom-in simulations carried out with the RAMSES code. To compare the models with observations, we postprocessed a snapshot of a bridge-like structure that is associated with a forming triple star system with the radiative transfer code POLARIS and produced multiwavelength dust polarization maps. Results. The typical density in the most prominent bridge of our sample is about 10−16 g cm−3, and the magnetic field strength in the bridge is about 1 to 2 mG. Inside the bridge, the magnetic field structure has an elongated toroidal morphology, and the dust polarization maps trace the complex morphology. In contrast, the magnetic field strength associated with the launching of asymmetric bipolar outflows is significantly more magnetized (~100 mG). At λ = 1.3 mm, and the orientation of the grains in the bridge is very similar for the case accounting for radiative alignment torques (RATs) compared to perfect alignment with magnetic field lines. However, the polarization fraction in the bridge is three times smaller for the RAT scenario than when perfect alignment is assumed. At shorter wavelength (λ ≲ 200 μm), however, dust polarization does not trace the magnetic field because other effects such as self-scattering and dichroic extinction dominate the orientation of the polarization. Conclusions. Compared to the launching region of protostellar outflows, the magnetic field in bridge-like structures is weak. Synthetic dust polarization maps of ALMA Bands 6 and 7 (1.3 mm and 870 μm, respectively) can be used as a tracer of the complex morphology of elongated toroidal magnetic fields associated with bridges.

A generalized 2-DOF model for optimal design of MDOF structures controlled by Tuned Mass Damper Inerter (TMDI)

The paper illustrates a methodology to perform the optimal design of a Tuned Mass Damper Inerter (TMDI) equipped on a multi degree of freedom (MDOF) structure through a generalized model. The TMDI is considered in both configurations grounded and ungrounded. A generalized 2-DOF model is obtained: the primary oscillator, representing the original MDOF structure and the secondary oscillator, representing the control system. A Gaussian zero mean white noise random process is adopted for the excitation. The TMDI design is carried out adopting an energy objective function, maximized over the space of the design parameters which are: the mass and inertance ratios, the frequency ratio, the damping factor and a parameter that accounts for the TMDI location on the MDOF structure. Synthetic performance-based design maps of the TMDI parameters are carried out. It is shown that is possible to have different design configurations to achieve a target performance level. The maps furnish, as limit cases, the design of a Tuned Inerter Damper (TID) and a Tuned Mass Damper (TMD), when the mass or the inertance ratios are respectively assumed null. It is shown straightforwardly the regions of the design parameters where the inerter enhances the performances achievable by classical TMD. Furthermore, an analytical expression which links the optimal design variables necessary to obtain a desired target performance is proposed. Frequency response functions and modal parameters of certain 2-DOF models with optimally designed control system are reported and considerations on how the design parameters influence the system dynamics and the damping capabilities are highlighted. Comparisons of the TMDI optimally designed with cases of no control and same mass TMD are evidenced throughout the paper. Finally, the main responses of the primary structure and the TMDI are estimated in the space of variation of the design parameters in order to assess the effectiveness of the control system.

Producing synthetic maps of dust polarization using a velocity channel gradient technique

ABSTRACT In modern cosmology, many efforts have been made to detect the primordial B-mode of cosmic microwave background polarization from gravitational waves generated during inflation. Considering the foreground dust contamination of microwave polarization maps, it is essential to obtain a precise prediction for polarization in dust emission. In this work, we show a new method to produce synthetic maps of dust polarization in the magnetized turbulent interstellar medium from more abundant high-resolution H i data. By using the velocity channel gradient technique, we are able to predict both the direction and degree of dust polarization by investigating spectroscopic H i information in position–position–velocity space. We apply our approach to the Galactic Arecibo L-band Feed Array H i data, and find a good correspondence between synthesized maps and Planck’s polarization measurements at 353 GHz.

Constraining the radial drift of millimeter-sized grains in the protoplanetary disks in Lupus

Context. Recent ALMA surveys of protoplanetary disks have shown that for most disks the extent of the gas emission is greater than the extent of the thermal emission of millimeter-sized dust. Both line optical depth and the combined effect of radially dependent grain growth and radial drift may contribute to this observed effect. To determine whether or not radial drift is common across the disk population, quantitative estimates of the effect of line optical depth are required. Aims. For a sample of ten disks from the Lupus survey we investigate how well dust-based models without radial dust evolution reproduce the observed 12CO outer radius, and determine whether radial dust evolution is required to match the observed gas–dust size difference. Methods. Based on surface density profiles derived from continuum observations we used the thermochemical code DALI to obtain 12CO synthetic emission maps. Gas and dust outer radii of the models were calculated using the same methods as applied to the observations. The gas and dust outer radii (RCO, Rmm) calculated using only line optical depth were compared to observations on a source-by-source basis. Results. For five disks, we find RCO, obs∕Rmm, obs > RCO, mdl∕Rmm, mdl. For these disks we need both dust evolution and optical depth effects to explain the observed gas–dust size difference. For the other five disks, the observed RCO∕Rmm lies within the uncertainties on RCO, mdl∕Rmm, mdl due to noise. For these disks the observed gas–dust size difference can be explained using only line optical depth effects. We also identify six disks not included in our initial sample but part of a survey of the same star-forming region that show significant signal-to-noise ratio (S∕N ≥ 3) 12CO J = 2−1 emission beyond 4 × Rmm. These disks, for which no RCO is available, likely have RCO∕Rmm ≫ 4 and are difficult to explain without substantial dust evolution. Conclusions. Most of the disks in our sample of predominantly bright disks are consistent with radial drift and grain growth. We also find six faint disks where the observed gas–dust size difference hints at considerable radial drift and grain growth, suggesting that these are common features among both bright and faint disks. The effects of radial drift and grain growth can be observed in disks where the dust and gas radii are significantly different, while more detailed models and deeper observations are needed to see this effect in disks with smaller differences.

Geomorphology of Naples and the Campi Flegrei: human and natural landscapes in a restless land

ABSTRACT Naples and its surroundings are a very young landscape, originated from 40 ka in response to strong and explosive volcanic processes, which created the Campi Flegrei, one of the largest volcanic fields of the world. Despite the repeated and continuous volcanic activity, this territory was selected for human settlements since Neolithic times and hosted some of the most important Greek and Roman towns in the Mediterranean area (e.g., Cuma, Parthenope, Neapolis, Baia and Puteoli). Geoarcheological data and historical chronicles testify to human coexistence with eruptions, bradyseismic ground motions, coastline changes, floods and landslides. With the aim of describing the geomorphological evolution of this area to a wide audience, including also non-experts, we constructed a synthetic geomorphological map of the area and sketches that synthesise the main stages of the geomorphological evolution of the historical centre of Naples and the coastal belt of the Gulf of Pozzuoli during the last millennia.

Introduction to the Special Issue

Introduction to the Special Issue

Young bilateral supernova remnants evolving into a turbulent interstellar magnetic field

ABSTRACT We employ 3D magnetohydrodynamic simulations to study the morphology and synchrotron emission of young supernova remnants evolving in a turbulent interstellar magnetic field, seeking to shed new light on to the polarization structure of the emission and on the debate concerning the quasi-parallel and quasi-perpendicular acceleration mechanisms. In the simulations, we consider a non-homogeneous interstellar medium magnetic field by introducing small random perturbations in the direction and intensity of the field. In order to analyse the dependence of the radio morphology on the degree of magnetic field perturbation and the observer’s point of view, we compute synthetic maps of the polarized intensity, position-angle, polarization fraction, and the polar-reference angle. By comparing the distribution of this angle to the polarization intensity, we show that it is possible to identify what type of acceleration mechanism is taking place at the main shock front.

Depth Map Denoising and Inpainting using Object Shape Priors

We present a system that improves the quality of noisy and incomplete depth maps captured with inexpensive range sensors. We use a model-based approach that measures the discrepancy between a model hypothesis and observed depth data. We represent the model hypothesis as a 3D level-setembedding function and the observed data as a point cloud coming from a segmented region associated to the object of interest. The discrepancy between the model and the observed data defines an objective function, that is minimized to obtain pose, scale and shape. The variation in shape of the object of interest is mapped with Gaussian Process Latent Variable Models GPLVM and the object pose is estimated using Lie algebra. The integration of a synthetic depth map, obtained from the optimal model, and the observed depth map is carriedout with variational techniques. As consequence, we work in the observed space (depth space) rather than in a high dimensional space (3D points or volumetric space), achieving outstanding results in the improved depth maps.

Depth Map Denoising and Inpainting using Object Shape Priors

We present a system that improves the quality of noisy and incomplete depth maps captured with inexpensive range sensors. We use a model-based approach that measures the discrepancy between a model hypothesis and observed depth data. We represent the model hypothesis as a 3D level-setembedding function and the observed data as a point cloud coming from a segmented region associated to the object of interest. The discrepancy between the model and the observed data defines an objective function, that is minimized to obtain pose, scale and shape. The variation in shape of the object of interest is mapped with Gaussian Process Latent Variable Models GPLVM and the object pose is estimated using Lie algebra. The integration of a synthetic depth map, obtained from the optimal model, and the observed depth map is carriedout with variational techniques. As consequence, we work in the observed space (depth space) rather than in a high dimensional space (3D points or volumetric space), achieving outstanding results in the improved depth maps.

Deep learning-based attenuation map generation for myocardial perfusion SPECT.

Attenuation correction using CT transmission scanning increases the accuracy of single-photon emission computed tomography (SPECT) and enables quantitative analysis. Current existing SPECT-only systems normally do not support transmission scanning and therefore scans on these systemsare susceptible to attenuation artifacts. Moreover, the use of CT scans also increases radiation dose to patients and significant artifacts can occur due to the misregistration between the SPECT and CT scans as a result of patient motion. The purpose of this study is to develop an approach to estimate attenuation maps directly from SPECT emission data using deep learning methods. Both photopeak window and scatter window SPECT images were used as inputs to better utilize the underlying attenuation information embedded in the emission data. The CT-based attenuation maps were used as labels with which cardiac SPECT/CT images of 65 patients were included for training and testing. We implemented and evaluated deep fully convolutional neural networks using both standard training and training using an adversarial strategy. The synthetic attenuation maps were qualitatively and quantitatively consistent with the CT-based attenuation map. The globally normalized mean absolute error (NMAE) between the synthetic and CT-based attenuation maps were 3.60% ± 0.85% among the 25 testing subjects. The SPECT reconstructed images corrected using the CT-based attenuation map and synthetic attenuation map are highly consistent. The NMAE between the reconstructed SPECT images that were corrected using the synthetic and CT-based attenuation maps was 0.26% ± 0.15%, whereas the localized absolute percentage error was 1.33% ± 3.80% in the left ventricle (LV) myocardium and 1.07% ± 2.58% in the LV blood pool. We developed a deep convolutional neural network to estimate attenuation maps for SPECT directly from the emission data. The proposed method is capable of generating highly reliable attenuation maps to facilitate attenuation correction for SPECT-only scanners for myocardial perfusion imaging.

Impact of a companion and of chromospheric emission on the shape of chromosome maps for globular clusters

Context. Globular clusters (GCs) host multiple populations of stars that are well-separated in a photometric diagram – the chromosome map – built from specific Hubble Space Telescope (HST) filters. Stars from different populations feature at various locations on this diagram due to peculiar chemical compositions. Stars of the first population, with field star-like abundances, sometimes show an unexpected extended distribution in the chromosome map. Aims. We aim to investigate the role of binaries and chromospheric emission on HST photometry of globular clusters’ stars. We quantify their respective effects on the position of stars in the chromosome map, especially among the first population. Methods. We computed atmosphere models and synthetic spectra for stars of different chemical compositions, based on isochrones produced by stellar evolution calculations with abundance variations representative of first and second populations in GCs. From this we built synthetic chromosome maps for a mixture of stars of different chemical compositions. We subsequently replaced a fraction of stars with binaries, or stars with chromospheric emission, using synthetic spectroscopy. We studied how the position of stars is affected in the chromosome map. Results. Binaries can, in principle, explain the extension of the first population in the chromosome map. However, we find that given the binary fraction reported for GCs, the density of stars in the extended part is too small. Another difficulty of the binary explanation is that the shape of the distribution of the first population in the chromosome map is different in clusters with similar binary fractions. Also, the decrease of the binary fraction with radius is not mirrored in the shape of the chromosome map. Additionally, we find that the contribution of chromospheric emission lines to the HST photometry is too small to have an observable impact on the shape of the chromosome map. Continuum chromospheric emission has an effect qualitatively similar to binaries. Conclusions. We conclude that binaries do have an impact on the morphology of the chromosome map of GCs, but they are unlikely to explain entirely the shape of the extended distribution of the first population stars. Uncertainties in the properties of continuum chromospheric emission of stars in GCs prevent any quantitative conclusion. Therefore, the origin of the extended first population remains unexplained.

The life cycle of the Central Molecular Zone - II. Distribution of atomic and molecular gas tracers.

We use the hydrodynamical simulation of our inner Galaxy presented in Armillotta etal. to study the gas distribution and kinematics within the Central Molecular Zone (CMZ). We use a resolution high enough to capture the gas emitting in dense molecular tracers such as NH3 and HCN, and simulate a time window of 50Myr, long enough to capture phases during which the CMZ experiences both quiescent and intense star formation. We then post-process the simulated CMZ to calculate its spatially dependent chemical and thermal state, producing synthetic emission data cubes and maps of both H i and the molecular gas tracers CO, NH3, and HCN. We show that, as viewed from Earth, gas in the CMZ is distributed mainly in two parallel and elongated features extending from positive longitudes and velocities to negative longitudes and velocities. The molecular gas emission within these two streams is not uniform, and it is mostly associated with the region where gas flowing towards the Galactic Centre through the dust lanes collides with gas orbiting within the ring. Our simulated data cubes reproduce a number of features found in the observed CMZ. However, some discrepancies emerge when we use our results to interpret the position of individual molecular clouds. Finally, we show that, when the CMZ is near a period of intense star formation, the ring is mostly fragmented as a consequence of supernova feedback, and the bulk of the emission comes from star-forming molecular clouds. This correlation between morphology and star formation rate should be detectable in observations of extragalactic CMZs.

ASSESSMENT AND MAPPING OF SOIL SENSITIVITY TO EROSION USING GIS IN MELLEGUE CATCHMENT, NORTHEAST OF ALGERIA

In Algeria, there is an urgent need for cartographic zones touched by erosion and also to target priority risk areas to improve the consistency of erosion prevention actions. Such a mapping must be able to display the areas at sensitivity to erosion and must take into account the developments to be undertaken. It is in this perspective that this study is carried out for (a) to map the sensitivity to erosion in the Mellegue catchment by relying on three factors of erosion namely topography, lithology and land use; and (b) to propose a management plan for vulnerable areas. This study is conducted using a Geographic Information System, which has allowed to characterize different areas of the study catchment and its sub-basins by producing a synthetic map of degrees of susceptibility to erosion.The results has shown that the basin has dominant areas of medium to high sensitivity to erosion, despite the existence of a considerable low sensitive area, corresponding to 47% of the basin area and observed mainly at the Meskiana sub-basin. The integration of the results into three levels of sub-basins has allowed identifying the most susceptible areas to erosion. This study provides sufficient data for a prioritization of the study basin according to their degree of erosion, making possible to the different actors, the management of the territory.

Studies of the influence of tropospheric factors on the formation of noctilucent clouds by a cartographic method

The influence of a certain type of tropospheric factors on the appearance and formation of noctilucent clouds at mid-latitudes is studied by utilizing a method of construction and analysis of synthetic weather maps. The method is based on a cartographic comparison of satellite images of large fields of noctilucent clouds over most of northern Eurasia and standard meteorological maps for the same territory. The time of obtained satellite images and meteorological maps coincides within up to half a day. Based on the full set of synthetic weather maps constructed for the 2015 summer season, it is statistically shown that in almost all cases the localization of noctilucent clouds fields is associated with the evolution of a number of typical weather processes in the troposphere. The most pronounced weather processes have been associated with the movement of cyclones and cold fronts, the development of occlusions and extensive thunderstorms. A general explanation of the revealed facts is proposed which is based on the influence of internal gravity waves, arising in the troposphere, on the cloud formation in the upper atmosphere. Prospects for further research on tropospheric-mesospheric interactions are considered.

Dimension Reduction and Analysis of a 10-Year Physicochemical and Biological Water Database Applied to Water Resources Intended for Human Consumption in the Provence-Alpes-Côte d’Azur Region, France

The SISE-Eaux database of water intended for human consumption, archived by the French Regional Health Agency (ARS) since 1990, is a rich source of information. However, more or less regular monitoring over almost 30 years and the multiplication of parameters lead to a sparse matrix (observations × parameters) and a large dimension of the hyperspace of data. These characteristics make it difficult to exploit this database for a synthetic mapping of water quality, and to identify of the processes responsible for its diversity in a complex geological context and anthropized environment. A 10-year period (2006–2016) was selected from the Provence-Alpes- Côte d’Azur region database (PACA, southeastern France). We extracted 5,295 water samples, each with 15 parameters. A treatment by principal component analysis (PCA) followed with orthomax rotation allows for identifying and ranking six principal components (PCs) totaling 75% of the initial information. The association of the parameters with the principal components, and the regional distribution of the PCs make it possible to identify water-rock interactions, bacteriological contamination, redox processes and arsenic occurrence as the main sources of variability. However, the results also highlight a decrease of useful information, a constraint linked to the vast size and diversity of the study area. The development of a relevant tool for the protecting and managing of water resources will require identifying of subsets based on functional landscape units or the grouping of groundwater bodies.

Indoor WLAN Intelligent Target Intrusion Sensing Using Ray-Aided Generative Adversarial Network

An indoor target intrusion sensing technique has been used in many fields, such as smart home management, security monitoring, counter-terrorism, and disaster relief. At the same time, with the wide deployment of wireless local area network (WLAN) and general support of the IEEE 802.11 protocol by various mobile devices, the target intrusion sensing can be realized based on the existing WLAN infrastructure without requiring the target to carry any special device. However, the existing indoor WLAN target intrusion sensing approaches usually depend on the radio map construction with huge labor and time cost, which is the major barrier of current systems. In response to this compelling problem, we propose the new ray-aided generative adversarial model (RaGAM) to automatically construct the radio map, which is used for the indoor WLAN intelligent target intrusion sensing and localization. To achieve the low labor and time cost, the RaGAM uses the adaptive-depth ray tree based the quasi three-dimensional ray-tracing model to depict the difference of WLAN signals between the silence and intrusion environments with the purpose of constructing the synthetic radio map. Considering the gap between the synthetic and actual radio maps, we modify the conventional generative adversarial network by the joint synthetic and unsupervised learning (or called S+U learning) from the actual unlabeled received signal strength (RSS) data to improve the precision of the proposed ray-tracing model, and consequently obtain the refined radio map. After that, the statistical characteristics of the refined radio map are utilized to construct the training set for the probabilistic neural network (PNN), and then by using the well-trained PNN to classify the newly collected RSS data, the target intrusion sensing, and localization are achieved. The experimental results show that the proposed approach cannot only perform well in terms of computation cost and the ray-tracing accuracy, but also sense the target intrusion states accurately.

SRMM: A Social Relationship-Aware Human Mobility Model

Since human movement patterns are important for validating the performance of wireless networks, several traces of human movements in real life have been collected. However, collecting data about human movements is costly and time-consuming. Moreover, multiple traces are demanded to test various network scenarios. As a result, a lot of synthetic models of human movement have been proposed. Nevertheless, most of the proposed models were often based on random generation, and cannot produce realistic human movements. Although there have been a few models that tried to capture the characteristics of human movement in real life (e.g., flights, inter-contact times, and pause times following the truncated power-law distribution), those models still cannot reflect realistic human movements due to a lack of consideration for social context among people. To address those limitations, in this paper, we propose a novel human mobility model called the social relationship–aware human mobility model (SRMM), which considers social context as well as the characteristics of human movement. SRMM partitions people into social groups by exploiting information from a social graph. Then, the movements of people are determined by considering the distances to places and social relationships. The proposed model is first evaluated by using a synthetic map, and then a real road map is considered. The results of SRMM are compared with a real trace and other synthetic mobility models. The obtained results indicate that SRMM is consistently better at reflecting both human movement characteristics and social relationships.