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We perform a joint analysis of gravity and magnetic data sets in the Tyrrhenian Sea region to infer the rock physical properties of several volcanic seamounts. We propose a moving‐window application using Poisson's theorem, which relates the total gradient of the magnetic field to the total gradient of the first‐order vertical derivative of the gravity field data. In volcanic environments, where strong intensity of remanent magnetization is expected, the total gradient of the magnetic field is particularly useful since it is almost independent on the direction of the total‐magnetization. The moving‐window approach resulted necessary due to the heterogeneous magnetization distribution of the volcanoes. First, we perform synthetic tests based on realistic seamount models which exhibit inhomogeneous magnetization intensity and orientation. Using the total gradients, we demonstrate that our approach can provide an appropriate magnetization‐to‐density ratio in different subareas of seamounts. The results of the correlation analysis for the Palinuro, Marsili, Vavilov, and Magnaghi seamounts provide interesting information on the variability of magnetization associated with different epochs of formation and demagnetization effects due to hydrothermal alteration processes. Plain Language Summary: We analyzed gravity and magnetic data sets to determine the rock properties of the main seamounts in Southern Tyrrhenian Sea. This study shows that the correlation analysis based on a window‐by‐window approach is an efficient tool for studying potential field anomalies in areas where inhomogeneous distribution of magnetization is expected. We also show that, by studying the total gradients of the magnetic field and the first order vertical derivative of the gravity field, the correlation analysis is almost insensitive to the direction of the remanent magnetization. We obtain interesting information on the variability in magnetization for each seamount and identify possible areas of demagnetization due to hydrothermal alteration processes. Key Points: We may infer the rock magnetization of seamounts by the correlation analysis of gravity and magnetic anomaliesThe study of the potential field total gradients is particularly useful when the source has strong remanent magnetizationWe found inhomogeneous magnetization in the Palinuro, Marsili, Magnaghi and Vavilov seamounts, likely due to hydrothermal activity [ABSTRACT FROM AUTHOR]

Abstract—The features of potential fields characterizing the Islas Orcadas and Meteor undersea rises located in the South Atlantic are considered. The rises are located at approximately the same distance to the west and to the east from the axis of the southern segment of the Mid-Atlantic Ridge. Density modeling along the profiles intersecting the rises was carried out. The analysis of potential fields and the results of density modeling shows a generally similar structure of the crust and lithosphere of the Islas Orcadas Rise and the Meteor Rise, which supports the common nature of their formation as a result of the splitting of the lithosphere of the small Agulhas plate due to kinematic restructuring, which led to the extinction of the Agulhas Ridge and formation of the southern segment of the Mid-Atlantic Ridge. However, some features in the density structure of these rises, both along their north-south trend where the influence of hot spots on the heating of the mantle is particularly evident, and along the conjugate profiles, indicate an asymmetric structure of the rises during the initial stage of their formation. [ABSTRACT FROM AUTHOR]

This paper proposes the complex dynamics of collective behavior through an interdisciplinary approach that integrates individual cognition with potential fields. Firstly, the interaction between individual cognition and external potential fields in complex social systems is explored, integrating perspectives from physics, cognitive psychology, and social science. Subsequently, a new modeling method for the multidimensional potential field mechanism is proposed, aiming to reduce individual behavioral errors and cognitive dissonance, thereby improving system efficiency and accuracy. The approach uses cooperative control and distributed learning algorithms to simulate collective behavior, allowing individuals to iteratively adapt based on local information and collective intelligence. Simulations highlight the impact of factors such as individual density, noise intensity, communication radius, and negative potential fields on collective dynamics. For instance, in a high-density environment with 180 individuals, increased social friction and competition for resources significantly decrease collective search efficiency. Validation is achieved by comparing simulation results with existing research, showing consistency and improvements over traditional models. In noisy environments, simulations maintain higher accuracy and group cohesion compared to standard methods. Additionally, without communication, the Mean Squared Error (MSE) initially drops rapidly as individuals adapt but stabilizes over time, emphasizing the importance of communication in maintaining collective efficiency. The study concludes that collective behavior emerges from complex nonlinear interactions between individual cognition and potential fields, rather than being merely the sum of individual actions. These insights enhance the understanding of complex system dynamics, providing a foundation for future applications in adaptive urban environments and the design of autonomous robots and AI systems. [ABSTRACT FROM AUTHOR]

The geological efficiency of seismic exploration and, as a result, the reliability of structural constructions in areas of intense tectonic dislocations (normal, reverse and thrust faults) is significantly reduced. At the same time, it is in such areas, that the presence of lithostratigraphic complexes contrasting in density or magnetic properties in the section and the abundance of subvertical boundaries provide prerequisites for the successful use of potential field methods (gravity exploration, magnetic exploration) to verify and supplement the structural interpretation of seismic exploration data. The paper presents the technology of complex interpretation of magnetic and seismic exploration data, tested on one of the objects of the Pechora Sea. In the course of the research, the connection of local magnetic anomalies with the seismic structural plan was established, which made it possible to identify and trace a magnetically active complex in the sedimentary strata with parameters typical of volcanogenic sedimentary rocks, weakly contrasting in seismic records. As a result of 3D modeling, the morphology of the roof and the base of the magnetic layer were determined, and the three-dimensional distribution of magnetization was calculated. It is proved that the sources of local magnetic field anomalies, a priori considered as isolated intrusive massifs, are associated with the distribution of magnetization within a single stratified volcanogenic-sedimentary strata. The obtained result was used in the construction of an updated geological and geophysical model. The developed technology is recommended as one of the promising approaches for building seismomagnetic models in similar physical and geological situations. [ABSTRACT FROM AUTHOR]

We analyzed magnetic data of a deep-water area in the Eastern Mediterranean, offshore Egypt where there are numerous salt domes. Regional-residual separation of the reduced to pole (RTP) magnetic anomalies was performed with the discrete wavelet transform, and the residual magnetic anomalies were interpreted as mainly due to the susceptibility contrast between sediments and salt bodies. A multiscale boundary analysis of the anomalies yielded meaningful lineaments at both large and short scales. Salt bodies lineaments are very well defined in the short-scale map. Then, we inverted the data by a nonlinear and non-iterative 3D inversion technique, to delineate the salt bodies and estimate their magnetization contrast. We used the depths obtained from the Euler deconvolution to form a set of maxima and minima constraints in the inversion. Our procedure yielded an interesting map of the top of salt in the deep-water region, entirely based on the magnetic data, which agrees well with the seismic top of salt. This is a somewhat surprising result, in some respects not obvious, demonstrating that magnetic prospecting can be an important and low-cost tool for the exploration of salt diapirs, especially when seismic data are partially or completely inaccessible or of poor quality. [ABSTRACT FROM AUTHOR]

Understanding vehicles’ movement in complex environments becomes cruical with the fast development of connected automated vehicles (CAVs). Current microscopic traffic flow models lack consideration for vehicle dynamics and complex road topologies. This study develops a model addressing these issues, retrieving vehicles’ maneuvers and predicting vehicles’ two-dimensional motion. It introduces a two-dimensional intelligent driving model utilizing steering angle and acceleration as control inputs. Intricate road topologies are represented with potential fields and a virtual boundary to capture the heterogeneous environment’s complexity. A driving potential field model is also developed for off-ramp areas. Model parameters are optimized with the dynamic time warping (DTW) and particle swarm optimization (PSO) algorithm. Furthermore, model predictive control (MPC) enhances the realism of the model’s output. Field validation results demonstrate that the proposed models can accurately describe vehicles’ two-dimensional movement in intricate environments, offering valuable support for research on heterogeneous traffic flows for CAVs and CVs. [ABSTRACT FROM AUTHOR]

In complex systems, single micro/nanorobots encounter challenges related to limited loading capacity and navigation, hindering their effective utilization in targeted therapy and drug delivery. To solve these challenges, this paper explores potential field mechanisms as a means to simulate natural collective behavior. This approach aims to enhance the navigation and efficiency of micro/nanorobots in high-demand therapeutic areas. The mechanism enables micro/nanorobots to dynamically adapt to environmental gradients, minimizing off-target effects while maximizing therapeutic efficacy and enhancing robustness through redundancy. Additionally, this study introduces innovative distributed learning and cooperative control strategies. Each micro/nanorobot updates its navigation strategy through local interactions and influences with the dynamic environment. This allows micro/nanorobots to share information and improve their navigation toward therapeutic targets. The simulation results demonstrate that collective behavior and potential field mechanisms can enhance the precision and efficiency of targeted therapy and drug delivery in dynamically changing environments. In conclusion, the proposed approach can improve the limitations of single micro/nanobot, offering new possibilities for the development of advanced therapeutics and drug delivery systems.

Robotic exploration has long captivated researchers aiming to map complex environments efficiently. Techniques such as potential fields and frontier exploration have traditionally been employed in this pursuit, primarily focusing on solitary agents. Recent advancements have shifted towards optimizing exploration efficiency through multiagent systems. However, many existing approaches overlook critical real-world factors, such as broadcast range limitations, communication costs, and coverage overlap. This paper addresses these gaps by proposing a distributed maze exploration strategy (CU-LVP) that assumes constrained broadcast ranges and utilizes Voronoi diagrams for better area partitioning. By adapting traditional multiagent methods to distributed environments with limited broadcast ranges, this study evaluates their performance across diverse maze topologies, demonstrating the efficacy and practical applicability of the proposed method. The code and experimental results supporting this study are available in the following repository: https://github.com/manouslinard/multiagent-exploration/.

This paper proposes the complex dynamics of collective behavior through an interdisciplinary approach that integrates individual cognition with potential fields. Firstly, the interaction between individual cognition and external potential fields in complex social systems is explored, integrating perspectives from physics, cognitive psychology, and social science. Subsequently, a new modeling method for the multidimensional potential field mechanism is proposed, aiming to reduce individual behavioral errors and cognitive dissonance, thereby improving system efficiency and accuracy. The approach uses cooperative control and distributed learning algorithms to simulate collective behavior, allowing individuals to iteratively adapt based on local information and collective intelligence. Simulations highlight the impact of factors such as individual density, noise intensity, communication radius, and negative potential fields on collective dynamics. For instance, in a high-density environment with 180 individuals, increased social friction and competition for resources significantly decrease collective search efficiency. Validation is achieved by comparing simulation results with existing research, showing consistency and improvements over traditional models. In noisy environments, simulations maintain higher accuracy and group cohesion compared to standard methods. Additionally, without communication, the Mean Squared Error (MSE) initially drops rapidly as individuals adapt but stabilizes over time, emphasizing the importance of communication in maintaining collective efficiency. The study concludes that collective behavior emerges from complex nonlinear interactions between individual cognition and potential fields, rather than being merely the sum of individual actions. These insights enhance the understanding of complex system dynamics, providing a foundation for future applications in adaptive urban environments and the design of autonomous robots and AI systems.

Quadruped robots have garnered significant attention in recent years due to their ability to navigate through challenging terrains. Among the various environments, agriculture fields are particularly difficult for legged robots, given the variability of soil types and conditions. To address this issue, this study proposes a novel navigation strategy that utilizes ground reaction forces to calculate online artificial potential fields, which are then applied to the robot's feet to avoid low-traversability regions. The strategy also incorporates the net vector of the attractive potential field towards the goal and the repulsive field to avoid slippery regions, which dynamically adjusts the quadruped's gait. A realistic simulation environment validates the proposed navigation framework with case studies on randomly generated terrains. A comprehensive comparison with baseline navigation methods is conducted to assess the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

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Advancements in UAVs have enabled them to act as flying access points that can be positioned to create an interconnected wireless network in complex environments. The primary aim of such networks is to provide bandwidth coverage to users on the ground in case of an emergency or natural disaster when existing network infrastructure is unavailable. However, optimal UAV placement for creating an ad hoc wireless network is an NP-hard and challenging problem because of the UAV's communication range, unknown users' distribution, and differing user bandwidth requirements. Many techniques have been presented in the literature for wireless mesh network deployment, but they lack either generalizability (with different users' distributions) or real-time adaptability as per users' requirements. This paper addresses the UAV placement and control problem, where a set of genetic-algorithm-optimized potential fields guide UAVs for creating long-lived ad hoc wireless networks that find all users in a given area of interest (AOI) and serve their bandwidth requirements. The performance of networks deployed using the proposed algorithm was compared with the current state of the art on several experimental simulation scenarios with different levels of communication among UAVs, and the results show that, on average, the proposed algorithm outperforms the state of the art by 5.62 % to 121.73 % . [ABSTRACT FROM AUTHOR]

Magnetic data can be acquired from a number of different platforms (e.g., ground, drone, helicopter) using a variety of sensors (e.g., caesium vapour‐type optically pumped magnetometers, fluxgate, superconducting quantum interference devices) with different flight line configurations. To detect a magnetic anomaly associated with a mineral commodity that is not exposed but is thought to be associated with the anomalous magnetic mineral content, it is necessary to optimize the survey parameters through a complete data integration process. Prior petrophysical measurements provide insight into the physical contrast that might be expected between adjacent lithologic units and between the ore zone and the encompassing lithology. Oriented rock samples provide access to magnetic remanence data through palaeomagnetic laboratory measurements. Knowing the typical morphology of the ore zone one can compute a forward model of the expected anomalous response and determine which combination of survey parameters provides the highest probability of detecting the commodity being sought. In this study, we analyse magnetic patterns associated with thin dipping skarn bodies from the Geyer mining district in Erzgebirge, Germany. Petrophysical measurements indicate that the skarns are more magnetic than the surrounding host rock. Partially oriented samples from a bore core record a Variscan age metamorphic remanence. Forward modelling indicates that clusters of skarn bodies are required to produce a reliably detectable magnetic signal. Ground, or low elevation drone surveys are needed to detect these anomalies with standard scalar‐type optically pumped magnetometer or fluxgate magnetic surveys. The enhanced spatial resolution and long‐wavelength rejection of a superconducting quantum interference device based full‐tensor magnetic gradiometer provide an improvement over optically pumped magnetometers for an aircraft‐based survey platform. [ABSTRACT FROM AUTHOR]

Quadruped robots have garnered significant attention in recent years due to their ability to navigate through challenging terrains. Among the various environments, agriculture fields are particularly difficult for legged robots, given the variability of soil types and conditions. To address this issue, this study proposes a novel navigation strategy that utilizes ground reaction forces to calculate online artificial potential fields, which are then applied to the robot’s feet to avoid low-traversability regions. The strategy also incorporates the net vector of the attractive potential field towards the goal and the repulsive field to avoid slippery regions, which dynamically adjusts the quadruped’s gait. A realistic simulation environment validates the proposed navigation framework with case studies on randomly generated terrains. A comprehensive comparison with baseline navigation methods is conducted to assess the effectiveness of the proposed approach.

Advancements in UAVs have enabled them to act as flying access points that can be positioned to create an interconnected wireless network in complex environments. The primary aim of such networks is to provide bandwidth coverage to users on the ground in case of an emergency or natural disaster when existing network infrastructure is unavailable. However, optimal UAV placement for creating an ad hoc wireless network is an NP-hard and challenging problem because of the UAV’s communication range, unknown users’ distribution, and differing user bandwidth requirements. Many techniques have been presented in the literature for wireless mesh network deployment, but they lack either generalizability (with different users’ distributions) or real-time adaptability as per users’ requirements. This paper addresses the UAV placement and control problem, where a set of genetic-algorithm-optimized potential fields guide UAVs for creating long-lived ad hoc wireless networks that find all users in a given area of interest (AOI) and serve their bandwidth requirements. The performance of networks deployed using the proposed algorithm was compared with the current state of the art on several experimental simulation scenarios with different levels of communication among UAVs, and the results show that, on average, the proposed algorithm outperforms the state of the art by 5.62% to 121.73%.

We describe here the results of the characterization of subsurface structures in an area of the south-eastern edge of the Bohemian Massif, in Austria by high-resolution geophysical survey techniques and advanced analysis methods of potential fields. The employed methods included potential field multiscale techniques for source-edge location and characterization of sources at depth. Our results confirmed the presence of already known structures: the location of the Diendorf Fault and the Moldanubian Shearzone are clearly recognized in the data at the same location as on the geological maps, even where the Diendorf fault is covered with sediments of the Molasse Basin. In addition, we detected several geological contacts between different rock types in the Bohemian Massif west of the Diendorf Fault. From our results, we were also able to quickly identify and image, without a priori information, previously unknown structures, such as faults with-depth-to-the top of about 500 m and magmatic intrusions about 400 m deep. [ABSTRACT FROM AUTHOR]

Construction of a 3D geological model for the eastern Lachlan Orogen provided a new reference model for a combined magnetic and gravity model of the Macquarie Arc, an intra-oceanic arc accreted to Gondwana during the Late Ordovician to early Silurian Benambran Orogeny. Geologically constrained, iterative 2.5 D forward modelling represented the entire thickness of the crust over a west-to-east profile extending for 230 km, approximately coinciding with seismic reflection profiles 99AGSL1 and 99AGSL2. The output model, referred to here as the Forbes model, confirms west-dipping thrust stacks of the Junee-Narromine and Molong volcanic belts of the Macquarie Arc, in packages that also comprise underlying arc basement, overlying Ordovician turbidites, and overlying Silurian–Devonian volcanic and sedimentary units. Ordovician rocks in the Parkes Fault Zone are distributed in wedges within a flower-fault structure. These structural elements are broadly similar to an earlier interpretation of the seismic profiles and corresponding potential-field models but differ in the nature of the substrate to the Macquarie Arc. The arc substrate is best fitted with physical properties broadly that of an intermediate calc-alkaline rock, rather than mid-ocean ridge basalt (MORB) as previously inferred. Highly magnetic metamafic rocks of the Jindalee Group appear to occupy relatively narrow fault-bounded slivers and may correspond to mafic volcanic rocks in the forearc rather than fragments of MORB basement. The thick intermediate-composition crustal profile required by the Forbes model cannot distinguish between an Izu-Bonin-like thickened arc or a compound of an Ordovician arc developed on a pre-existing Cambrian arc, but the simple MORB substrate previously assumed for the Macquarie Arc can be excluded, as can obduction of the Macquarie Arc as a nappe over the Wagga Belt. A 3D model for the Lachlan Orogen provides geological constraints on joint magnetic and gravity model across the accreted intra-oceanic Macquarie Arc. The substrate of the arc is best fitted with magnetic susceptibility and density typical of an intermediate composition, in contrast with previous interpretations that the substrate preserves an oceanic crust basement. Western and central belts of the Macquarie Arc are stacked by west-dipping thrusts, inconsistent with emplacement as an allochthonous nappe. [ABSTRACT FROM AUTHOR]

The the southwestern part of the Indian Ocean, where the Mozambique and Madagascar ridges are located was studied. The ideas about the tectonic structure of these ridges are still under debate. The anomalous structure of the crust of these ridges can be explained either by underplating (thickening of the oceanic crust from below due to magmatism), or by stretching and thinning of the continental crust. Based on the data on anomalous gravitational and magnetic fields, seismotomography, and other geological and geophysical information, density modeling was performed along four profiles, which revealed differences in the crustal structure and evolution of the Mozambique and Madagascar ridges. [ABSTRACT FROM AUTHOR]

In complex systems, single micro/nanorobots encounter challenges related to limited loading capacity and navigation, hindering their effective utilization in targeted therapy and drug delivery. To solve these challenges, this paper explores potential field mechanisms as a means to simulate natural collective behavior. This approach aims to enhance the navigation and efficiency of micro/nanorobots in high-demand therapeutic areas. The mechanism enables micro/nanorobots to dynamically adapt to environmental gradients, minimizing off-target effects while maximizing therapeutic efficacy and enhancing robustness through redundancy. Additionally, this study introduces innovative distributed learning and cooperative control strategies. Each micro/nanorobot updates its navigation strategy through local interactions and influences with the dynamic environment. This allows micro/nanorobots to share information and improve their navigation toward therapeutic targets. The simulation results demonstrate that collective behavior and potential field mechanisms can enhance the precision and efficiency of targeted therapy and drug delivery in dynamically changing environments. In conclusion, the proposed approach can improve the limitations of single micro/nanobot, offering new possibilities for the development of advanced therapeutics and drug delivery systems., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Geomagnetic measurements detect the superposition of both regional and residual anomalies. Regional anomalies are caused by deep geological structures, while the residual ones are due to shallow sources. The presence of regional anomalies complicates the interpretation of magnetic data; to this end, a variety of techniques have been proposed for regional-residual anomaly separation. Most of them are based on Fourier transforms. Although valid results can be obtained from these methods, they have some limitations, such as requiring basic knowledge on approximate cut-off frequencies. This study focuses on spatial filtering employing factorial kriging (FK) for geomagnetic anomaly separation. FK employs geostatistical filtering based on spatial dependencies of the data. In contrast to the upward continuation, which is a trial and error method and needs to be checked with different distances of continuations, the utilisation of FK on synthetic data revealed that FK could automatically perform the separation and also helps to find the optimum distance for the upward continuation method. Following experiments with a synthetic model, the method was applied to real magnetic data of Bashmaq in northwestern Iran. Applying FK on a complicated real case study showed that it could separate the regional and residual components satisfactorily. Furthermore, results from the proposed approach have been compared against the Gaussian Separation Method (GSM). The results are compared to borehole information. The lithological columns are presented as part of the geology investigation. As demonstrated in the case study, the FK method has proven to be an accurate tool to better determine the mineralisation zones compared to GSM, which, in turn, facilitates the interpretation. [ABSTRACT FROM AUTHOR]

We describe here the results of the characterization of subsurface structures in an area of the south-eastern edge of the Bohemian Massif, in Austria by high-resolution geophysical survey techniques and advanced analysis methods of potential fields. The employed methods included potential field multiscale techniques for source-edge location and characterization of sources at depth. Our results confirmed the presence of already known structures: the location of the Diendorf Fault and the Moldanubian Shearzone are clearly recognized in the data at the same location as on the geological maps, even where the Diendorf fault is covered with sediments of the Molasse Basin. In addition, we detected several geological contacts between different rock types in the Bohemian Massif west of the Diendorf Fault. From our results, we were also able to quickly identify and image, without a priori information, previously unknown structures, such as faults with-depth-to-the top of about 500 m and magmatic intrusions about 400 m deep.

The downward continuation of potential fields is a process of calculating their values in a lower plane based on those of a certain plane. This technology is not only a data processing method for resource exploration but also plays an extremely important role in military applications. However, the downward continuation of potential fields is a typical linear inverse problem that is ill-posed. Generalized minimal residuals (GMRES) is an effective solution to ill-posed inverse problems, but it is unstable under the condition wherein the GMRES is directly applied in the calculation process. Moreover, the long-term behavior of its iterative computation is a disordered, divergent result. Therefore, to obtain stable solutions, GMRES is applied to solve the normal equations of the downward continuation of potential fields; it is also used to prequalify for occasional interruptions in the operation process by adding the damping coefficient, thus strengthening the stability conditions of the equations of residual minimization. Finally, the stable downward continuation of the potential fields method is proposed. As indicated by the theoretical data and the measured testing data, the method proposed in this paper has the advantages of high-precision and excellent stability. Furthermore, compared with the Tikhonov iteration method, the proposed method avoids the need to choose regularization parameters. [ABSTRACT FROM AUTHOR]

This study considers the anomalous gravity and magnetic fields in the Alutaguse petrological–structural domain, eastern Estonia. A 10 km wide local maximum (+6.26 mGal) Bouguer anomaly field was discovered at 58.96°N, 26.61°E from the ground gravity data by the Estonian Land Board in 2010–2011. The ground magnetic field intensity measurements indicated a positive magnetic anomaly of 600 nT, in addition to the local gravity maximum. Based on depth estimations, the centre of the anomaly source is placed at 2500–3000 m within the ~1.8 to 1.9 Ga Svecofennian basement. To provide information on the physical properties of the causative source of the anomalies, the geophysical modelling of potential fields was carried out by testing a number of lithologies as sources. The lithologies considered were the known post-orogenic and anorogenic magmatic intrusions in the Estonian basement, as well as typical metamorphic rocks of the Alutaguse domain. The obtained models indicate that the Luusika feature has a range of densities from 2760 to 2920 kg/m3 and magnetic susceptibilities from 20 000 × 10–6 to 56 000 × 10–6 SI. These models suggest that the Luusika causative source is an intermediate to the mafic rock unit, similar to post-orogenic or anorogenic massifs of the Svecofennian basement of Estonia.

Industrial robotics, military, surveying, and delivery applications have laid a foundation for research into autonomous machines, including unmanned aerial vehicles, autonomous ground vehicles, and autonomous undersea vehicles. This paper supports this research by developing a new guidance method which combines potential fields, typically used for obstacle avoidance, and parallel navigation, a popular missile guidance method. The new unified algorithm allows a mobile robot interceptor to guide to, and rendezvous with, a moving target while avoiding obstacles in its path. A Matlab simulator is used to analyze performance for different interceptor-target geometries and obstacle densities. Simulations and analysis show that the combined algorithm increases performance by reducing the time-to-contact in most of the cases. Specifically, it was found to provide a 14.4%–21.3% improvement in approximately 96%–98% of the simulation cases.

An elegant four-dimensional Lorentz-invariant first-integral of the energy–momentum equations for viscous flow, comprised of a single tensor equation, is derived assuming a flat space–time and that the energy–momentum tensor is symmetric. It represents a generalisation of corresponding Galilei-invariant theory associated with the classical incompressible Navier–Stokes equations, with the key features that the first-integral: (i) while taking the same form, overcomes the incompressibility constraint associated with its two- and three-dimensional incompressible Navier–Stokes counterparts; (ii) does not depend at outset on the constitutive fluid relationship forming the energy–momentum tensor. Starting from the resulting first integral: (iii) a rigorous asymptotic analysis shows that it reduces to one representing unsteady compressible viscous flow, from which the corresponding classical Galilei-invariant field equations are recovered; (iv) its use as a solid platform from which to solve viscous flow problems is demonstrated by applying the new general theory to the case of propagating acoustic waves, with and without viscous damping, and is shown to recover the well-known classical expressions for sound speed and damping rate consistent with those available in the open literature, derived previously as solutions of the linearised Navier–Stokes equations. [ABSTRACT FROM AUTHOR]

We show that high‐resolution aeromagnetic surveys, although rarely employed in the research of salt structures, may be an effective and low‐cost tool for mapping diapirism. A multiscale analysis of a high‐resolution magnetic data set at Nordkapp Basin in the Barents Sea, allows a clear reconstruction of the main salt diapirs of the basin using Multiridge and Compact Depth from Extreme Points methods. We provide a 3‐D model of the diapirs extended from 500 to 4,000 m below sea level, characterized by a general low magnetization contrast no larger than −0.08 A/m. The 3‐D model is consistent with the salt top depth estimated by 2‐D seismics, with borehole data and with the 2‐D gravity model of the Uranus diapir. Our imaging shows the capability of the magnetic method that gives new and comprehensive pictures of salt diapirism. Key Points: We interpret the magnetic field of the Nordkapp Basin by a multiscale approachImaging methods applied to magnetic data can well identify the top, bottom, and shape of saline structuresHigh‐resolution aeromagnetic surveys are a valid and low‐cost tool for mapping diapirism where other methods are not entirely effective [ABSTRACT FROM AUTHOR]

Rotor blades of large, modern wind turbines are susceptible to lightning strikes. In order to produce a design that resists lightning strikes, it is crucial to simulate lightning current propagation in the blade components. Since the current in the blade is generated by the superposition of potential and induced electric fields, a coupling exists between electric and magnetic fields which need to be calculated by an imposed integral constraint at each time step. Commercial software packages can deal with such constraints, but it results in time‐consuming computations. Therefore, this work aims to develop a numerical methodology able to compute the voltage which drives the lightning current through the structure. In this way, the problem is reformulated as a voltage‐driven one which in turn allows a simple subsequent coupling of electrical and magnetic problems. The computation of the voltage waveform was accomplished using the fast Fourier transform and the finite element method (FEM) to compute the structure impedance in the frequency domain. The developed procedure showed high efficiency for a blade subjected to different lightning impulses. It allows a description of the time‐dependent lightning current to be given, as well as the distribution of current within the blade conductors. [ABSTRACT FROM AUTHOR]

The Kerguelen Plateau is the largest submarine rise in the southern Indian Ocean. The heterogeneous structure of the crust, plume magmatic activity, and different ages of the adjacent basins indicate different structures of different marginal zones of the plateau. On the basis of geological and geophysical information, various morphodynamic types of margins of the Kerguelen Plateau are identified. Analysis of the bottom topography and potential field data, together with two-dimensional density modeling, allows us to specify the deep structure of the tectonosphere in the Kerguelen Plateau margins and take a fresh look at their nature. [ABSTRACT FROM AUTHOR]

A study of the fracture systems in the basement of the Matatlan urban waste dump of Guadalajara City, near the western edge of the Rio Grande de Santiago canyon (southwestern Mexico), is reported. The Matatlan dumpsite was developed on top of andesitic and rhyolitic rocks. Measurements at outcrops indicated that N–S (0°–15° and 165°–180°), N45–90E and N105–135E fracture systems affect the basement. Statistical analysis (micromagnetic method) of magnetic lineament azimuths indicated the presence of two lineament groups. The major one (N60–120E) has a maximum at N90–105E, and a secondary group (N120–165E). The gravity anomalies are featured by a major group (N60–120E, with maximums at N60–75E, and N105–120E) and a secondary group (N120–180E). Thus, a good to fair correlation exists between the measured fracture orientations and the lineaments featuring the gravity and magnetic anomalies. Horizontal derivative and tilt angle depicted horizontal limits of anomaly‐causative bodies. Results of the micromagnetic method are consistent with fracture orientations and with the limits established through edge‐detection techniques. Lineaments established by means of the gravity and magnetic Euler deconvolution are also consistent. Gravity and magnetic Euler deconvolution helped to estimate the depth extent of the limits of gravity and magnetic common sources. Euler deconvolution indicated the fault or contact nature of these lineaments. Furthermore, Euler deconvolution indicated slopes of the limits of gravity and magnetic sources. The fault or fracture nature of the major lineaments was finally confirmed by forward modelling (forward 2D cooperative modelling of gravity and magnetic profiles). For example, lineaments delimiting the northern depression could be characterized as normal faults. In general, this study indicates that it is possible, based on gravity and magnetic data, to characterize fractures affecting the basement of a dumpsite, a key parameter in hydrogeophysical studies. In particular, through this study, the inferred structures could be associated with regional tectonic faulting, which might provide migration paths to unhealthy lixiviate outside the dumpsite, giving rise to the contamination of the neighbouring environment. In particular, the study explains the presence of an unhealthy leachate waterfall to the northeast of the dumping site. Heavy metal contents in samples from this waterfall support that lixiviates originate at the dumpsite. [ABSTRACT FROM AUTHOR]

We present a brief review of the widely used and well‐known stabilizers in the inversion of potential field data. These include stabilizers that use L2, L1 and L0 norms of the model parameters and the gradients of the model parameters. These stabilizers may all be realized in a common setting using two general forms with different weighting functions. Moreover, we show that this unifying framework encompasses the use of additional stabilizations which are not common for potential field inversion. [ABSTRACT FROM AUTHOR]

This article deals with the issue of trajectory optimization of autonomous terrestrial vehicles on a specific range handled by the human driver. The main contributions of this paper are a genetic algorithm-potential field combined method for optimized trajectory planning, the definition of the multi-criteria optimization problem by including a time variable, dynamical vehicle constraints, obstacle motion for collision avoidance, and improvements on the attractive and repulsive potential field definitions. The main interests of the proposed method are its efficiency even in only arc-connected spaces with holes, trajectory optimality thanks to the genetic algorithm that minimizes multi-criteria optimization, reactivity thanks to the potential field through the consideration for nature and motion of obstacles, its orientation toward situations a human driver would consider, and finally the inclusion of constraints to avoid danger and to take into account vehicle dynamics. The global trajectory, optimized through genetic algorithm, is used as a reference in a fractional potential field, which is a reactive local path planning method. The repulsive potential field is made safer by adding fractional orders to the obstacles, and the attractive potential field is improved by creating a dynamical optimal target seen from a robust control point of view. This target replaces the unique attractive potential field point and avoids its drawbacks such as local minima. Autonomous car simulation results are given for a crossroad and an overtaking scenarios. [ABSTRACT FROM AUTHOR]

The modes in which the lithosphere deforms during continental collision and the mechanisms involved are not well understood. While continental subduction and mantle delamination are often invoked in tectonophysical studies, these processes are difficult to be confirmed in more complex tectonic regions such as the Gibraltar Arc. We study the present‐day density and compositional structure of the lithosphere along a transect running from South Iberia to North Africa crossing the western Gibraltar Arc. This region is located in the westernmost continental segment of the African‐Eurasian plates, characterized by a diffuse transpressive plate boundary. An integrated and self‐consistent geophysical‐petrological methodology is used to model the lithosphere structure variations and the thermophysical properties of the upper mantle. The crustal structure is mainly constrained by seismic experiments and geological data, whereas the composition of the lithospheric mantle is constrained by xenolith data. The results show large lateral variations in the topography of the lithosphere‐asthenosphere boundary. We distinguish different chemical lithospheric mantle domains that reproduce the main trends of the geophysical observables and the modeled P and S wave seismic velocities. A sublithospheric body colder than the surrounding mantle is needed beneath the Betics‐Rif to adjust the measured potential fields. We link this body to the Iberian slab localized just to the east of the profile and having some effect on the geoid and Bouguer anomalies. Local isostasy allows explaining most of the topography, but an elastic thickness higher than 10 km is needed to explain local misfits between the Atlas and the Rif Mountains. Key Points: Lithosphere structure and upper mantle thermophysical properties in the Gibraltar Arc‐Atlas is obtained using an integrated geophysical‐petrological modelA sublithospheric thermo‐compositional anomaly is found across the Iberia‐Africa plate boundary (Gibraltar)The thick lithosphere beneath the Betics and Rif tectonic domain, related to the W‐E slab, pulls down the topography about 1,500 m [ABSTRACT FROM AUTHOR]