Dangerous Regions Research Articles

Iterative graph deformation for aircraft trajectory planning considering ensemble forecasting of thunderstorms

Convective weather poses a major threat that compromises the safe operation of flights while inducing delay and cost. The aircraft trajectory optimization problem under thunderstorms is addressed, proposing a novel heuristic approach that incorporates uncertainties in the evolution of convective cells. Namely, the Augmented Random Search (ARS) algorithm is used to deform a directed graph iteratively in the search of an optimal path. Flight time and fuel consumption are optimized while avoiding unsafe regions. By means of parallel programming on graphical processing units (GPUs), the computational times are reduced to enable near real-time operation. The suggested method is tested considering a dynamic model of an aircraft flying between two waypoints at constant flight level; the test scenario consists of a real weather forecast described by an ensemble of equiprobable members. The influence of the maximum number of iterations and the relative weights between optimization objectives is analysed. Results show that the methodology is able to avoid dangerous regions and find the balance between total time of flight and fuel consumption.

The Conditional Probability of Correlating East Pacific Earthquakes with NOAA Electron Bursts

A correlation between low L-shell 30–100 keV electrons precipitating into the atmosphere and M ≥ 6 earthquakes in West Pacific was presented in past works where ionospheric events anticipated earthquakes by 1.5–3.5 h. This was a statistical result obtained from the Medium Energy Protons Electrons Detector on board the NOAA-15 satellite, which was analyzed for 16.5 years. The present analysis, utilizing the same database, translated into adiabatic coordinates during geomagnetic quiet periods, lead to another significant correlation regarding East Pacific strong earthquakes. This new correlation is still observed between high energy precipitating electrons detected by the NOAA-15 0° telescope and M ≥ 6 events of another very dangerous seismic region of the Pacific ring of fire. The particle precipitation that contributed to this correlation was characterized by electron L-shell, pitch-angle, possible disturbance altitudes, and geographical locations. This correlation occurred circa 57 h prior to the East Pacific earthquakes, according to past single cases of reports. The conditional probability corresponding to the cross-correlation peak of 0.024 per binary events reached a value of 0.011. A probability gain of 2 was calculated for earthquakes after an independent L-shell EBs detection, it is therefore applicable for future earthquake forecasting experiments. Moreover, a time-dependent probability gain approaching the correlation peak was estimated.

Predict the Rover Mobility Over Soft Terrain Using Articulated Wheeled Bevameter

Robot mobility is critical for mission success, especially in soft or deformable terrains, where the complex wheel-soil interaction mechanics often leads to excessive wheel slip and sinkage, causing the eventual mission failure. To improve the success rate, online mobility prediction using vision, infrared imaging, or model-based stochastic methods have been used in the literature. This paper proposes an on-board mobility prediction approach using an articulated wheeled bevameter that consists of a force-controlled arm and an instrumented bevameter (with force and vision sensors) as its end-effector. The proposed bevameter, which emulates the traditional terramechanics tests such as pressure-sinkage and shear experiments, can measure contact parameters ahead of the rover's body in real-time, and predict the slip and sinkage of supporting wheels over the probed region. Based on the predicted mobility, the rover can select a safer path in order to avoid dangerous regions such as those covered with quicksand. Compared to the literature, our proposed method can avoid the complicated terramechanics modeling and time-consuming stochastic prediction; it can also mitigate the inaccuracy issues arising in non-contact vision-based methods. We also conduct multiple experiments to validate the proposed approach.

Analyzing the Synchronous Acoustic and Electric Response of Coal Burst Failure: Validation through the On-Site Application

The accurate monitoring and early warning of coal and rock dynamic disasters become challenging in complex geological environments. Mostly, the signal information contains interferences, which misguides the technician, and thus leads to inaccurate monitoring results. To reduce the influence of interference signals, the synchronous response of the acoustic emission (AE) and electromagnetic emission (EME) signals before the failure of coal specimens during uniaxial loading was investigated in this study. Additionally, the coupling relationship between M value, AE energy/AE ringing count per unit time, and the damage of coal is established, and the early warning index of AE and EME (R value) was computed and verified through the field investigations. The results show that a strong synchronization of the acoustoelectric signals occurs only after the specimen enters the strain strengthening area. The analysis of the obtained results showed that the M value of the AE-EME synchronous response signal represents a strong degree of damage occurring in the coal body, however, this is still subject to false alarms. In contrast, the analysis of the R value accurately helped in determining the damage evaluation, thus, it can be regarded as one of the precursors of the imminent failure of coal. With R > 1, the specimen is closed to the failure state, thereby dangerous regions are identified with a dense concentration of R > 1 events. The obtained R value index through on-site AE and EME monitoring corresponds closely with the stress distribution cloud map of the roadway. It is inferred that the anti-interference ability and the reliability of the R value index are stronger than the routine early warning indicators of the single-AE or EME energy.

LEGAL STATE OF DOCTORS WITHOUT BORDERS (MÉDECINS SANS FRONTIÈRES) IN THE INTERNATIONAL LAW

Médecins Sans Frontières (MSF) is a non-profit organization that offers health and medical services to people based on their requirements irrespective of race, gender, beliefs, religion, and political origins. Physicians, as the MSF's most important members, assist people in their greatest need. They provide services ranging from consultations, vaccinations, and primary care to the most complex surgeries. Given that the doctors in the organization are very active members of the MSF and understand the risk of their presence in dangerous regions with prevalent epidemic and contagious diseases or under distress, insecurity, and war in underdeveloped or third world countries, research into the legal status of this self-giving and venture group of the international society is critical. The legal status of humanitarian aid workers such as the physicians in doctors without borders in international law has not been studied and recognized. This is due to the absence of a complete definition of “humanitarian aid workers” in international humanitarian law. Furthermore, the issue of the status of humanitarian NGOs in international law is novel. Therefore, studying the legal status of the humanitarian aid workers is an essential case because they are exposed to many potential risks in facing armed conflicts. This research planned a web-based survey as part of our study to find articles, books, reports, or studies in relationship with national and international humanitarian organizations and workers, NGOs, and the legal status of these organizations and their workers. We did normative legal research using secondary data from the internet, references, etc. While the operation of the MSF is mainly aimed at supporting the survival and recovery of people within a war or disease outbreak-afflicted country, its efforts put the lives of its personnel at risk. Herein, we will investigate how the MSF can adequately support its primary staff, the physicians. We can get the response to this question by studying the legal status of the doctors without borders in international law.

LEGAL STATE OF DOCTORS WITHOUT BORDERS (MÉDECINS SANS FRONTIÈRES) IN THE INTERNATIONAL LAW

Médecins Sans Frontières (MSF) is a non-profit organization that offers health and medical services to people based on their requirements irrespective of race, gender, beliefs, religion, and political origins. Physicians, as the MSF's most important members, assist people in their greatest need. They provide services ranging from consultations, vaccinations, and primary care to the most complex surgeries. Given that the doctors in the organization are very active members of the MSF and understand the risk of their presence in dangerous regions with prevalent epidemic and contagious diseases or under distress, insecurity, and war in underdeveloped or third world countries, research into the legal status of this self-giving and venture group of the international society is critical. The legal status of humanitarian aid workers such as the physicians in doctors without borders in international law has not been studied and recognized. This is due to the absence of a complete definition of “humanitarian aid workers” in international humanitarian law. Furthermore, the issue of the status of humanitarian NGOs in international law is novel. Therefore, studying the legal status of the humanitarian aid workers is an essential case because they are exposed to many potential risks in facing armed conflicts. This research planned a web-based survey as part of our study to find articles, books, reports, or studies in relationship with national and international humanitarian organizations and workers, NGOs, and the legal status of these organizations and their workers. We did normative legal research using secondary data from the internet, references, etc. While the operation of the MSF is mainly aimed at supporting the survival and recovery of people within a war or disease outbreak-afflicted country, its efforts put the lives of its personnel at risk. Herein, we will investigate how the MSF can adequately support its primary staff, the physicians. We can get the response to this question by studying the legal status of the doctors without borders in international law.

Prediction of Wildfires Based on the Spatio-Temporal Variability of Fire Danger Factors

Most methods in the field of wildfire prevention are based on expert assessment of fire danger factors. However, their weights are usually assumed constant for the entire application area despite the geographical and seasonal changes of factors. This study aimed to develop a wildfire prevention method based on partial and general fire danger ratings taking into account their spatio-temporal variability. The study was conducted for Krasnoyarsk territory, Orenburg region and the Meschera lowland as the most forest, steppe and peat fire dangerous regions of Russia respectively. Surface temperature, moisture, vegetation structure, anthropogenic load, topography and their variation over subzones and in time were used as fire danger factors. They were evaluated by measuring parameters such as radiobrightness temperature, Normalized Difference Water Index (NDWI), Normalized Difference Vegetation Index (NDVI), Soil-Adjusted Vegetation Index (SAVI), distance to settlements and roads, elevation, slope and aspect. Materials from the Terra/Aqua, Sentinel-3, Landsat-8, Sentinel-2 satellites, ASTER Global Digital Elevation Model and Open Street Maps vector layers were used in the study. Correlation between these parameters and the actual fires in 2016-2018 was analyzed. Linear relationships were established, and correlation coefficients, equations of partial ratings and prevention 90%-threshold values were identified. On their basis, the parameter weights were computed to integrate them into the general fire danger rating. The developed method was validated using data over 2019. The results showed 67% confidence and 61% reliability of fire prevention along with the spatio-temporal patterns of fire danger factors. The method is recommended for preventing wildfires within the study areas and can be extend to similar regions.

DeepGlobal: A framework for global robustness verification of feedforward neural networks

Feed forward neural networks (FNNs) have been deployed in a variety of domains, though achieving great success, also pose severe safety and reliability concerns. Existing adversarial attack generation and automatic verification techniques cannot formally verify a network globally, i.e., finding all adversarial dangerous regions (ADRs) of a network is out of their reach. To address this problem, we develop a global robustness verifiable FNN framework DeepGlobal with four components: 1) a rule-generator finding all potential boundaries of a network by logical reasoning; 2) a new network architecture Sliding Door Network (SDN) enabling rule generation in a feasible way; 3) a selector which selects real boundaries from the generated potential boundaries; 4) a filter finding ADRs with meaningful adversarial examples. The ADRs can be represented by the identified real boundaries. We demonstrate the effectiveness of our approach on both synthetic and real datasets.

Research on collaborative control technology of coal spontaneous combustion and gas coupling disaster in goaf based on dynamic isolation

Coupled thermodynamic disasters in goaf, such as coal fires and gas explosions have long been one of the most serious disasters in major accidents of coal mines worldwide. In the case of deep mining becoming the new normal of future mine mining, there is still a lack of targeted technical methods for the prevention and treatment of major thermodynamic disasters, especially coal spontaneous combustion and gas coupling disaster. Rapid dangerous region identification and effective prevention of such disasters in goaf is extremely important for mine safety production. Based on the analysis of the coupling relationship between coal spontaneous combustion and gas disaster in fully mechanized caving goaf and the mechanism of collaborative control technology, coal spontaneous combustion and gas disaster formation characteristics, occurrence process and prevention and control methods were fully utilized. By injecting isolation material through the interval between the hydraulic support frames to form a row of discontinuous isolation blocking zones, a dynamic pressure injectionisolation technology for collaborative control of coupling thermodynamic disaster in goaf in special mining period was proposed and the isolation parameters of the field goaf were designed. The field measurement was carried out to obtain data and the distribution characteristics of spontaneous combustion-prone. The gas drainage and collaborative control efficiency befor an after isolation were verified. Our approach offers a new concept and method to identify and collaboratively control of coal spontaneous combustion and gas coupling disasters in goaf, which provides theoretical and technical ideas for the prevention and control of such disasters and guarantees the safe and efficient mining of deep mines.

Effects of landing gear layout on the safe rollout envelope of equipped–skid aircraft

Rollout is an inevitable phase of realizing horizontal landing for an equipped–skid aircraft; therefore, one should pay attention to the safety of the entire rollout process. The research presented herein analyzes the effects of the landing gear layout on the safe rollout envelope, which is the set of all states where the aircraft can remain in the desired state region during the entire rollout phase. First, the nonlinear reachability analysis and its internal relation with a safe envelope are briefly described. To improve the calculation efficiency of approximating the safe envelope, a mixed implicit explicit (MIE) scheme is introduced. Subsequently, a simple yet accurate model of nonlinear aircraft dynamics is established and the dangerous state region during the rollout phase is defined. Finally, based on the numerical results, the effects of the layout type on the safe envelope are discussed. In addition, a reasonable safety evaluation index is proposed to quantitatively analyze the effects of position parameters on the rollout safety. The results indicate that with the application of the variable friction skid, the safe envelope of the wheel–skid aircraft is larger than that of the all–skid aircraft. Compared with the original position parameters, the optimized values increase the rollout safety of the wheel–skid aircraft by 4.18%.

The relationship of strong earthquakes, volcanoes and typhoons in the Philippine plate region as a result of the mutual influence of geospheres

The Philippine lithospheric plate is located at the intersection of the zones of intense influence of geosystems responsible for the evolution of the Earth’s outer shells, and is one of the most dangerous regions of the globe. The study of temporal variations of natural disasters at the end of the 20th — beginning of the 21st century is based on lies the premise of the relationship of strong earthquakes, volcanic eruptions and tropical atmospheric eddies in areas of complex high instability of geospheres.

ASPECTS OF PROVIDING THE BALANCED DEVELOPMENT OF LOCAL BUDGETS UNDER THE CONDITIONS OF MARITAL LAW

Objective. The objective of the study is the analysis of current measures for the budget process organizing and the identification of alternative sources of balancing local budgets in the conditions of martial law in order to reduce the negative impact of war on the formation of local budgets and the implementation of operational management of the formation of territorial communities' resources. Methods. A set of general and special methods of scientific research of economic processes were used, in particular: a systematic approach, comparison, grouping, detailing, generalization, methods of statistical analysis, etc. Results. Aspects of providing the balanced development of local budgets under martial law are studied. It was determined that during the independence of Ukraine, martial law was never introduced, therefore there are no studies of theoretical and practical aspects of the formation of local budgets in the specified conditions. It was noted that the local budgets assumed a significant part of the costs for the formation of the resource potential for effective countermeasures against the enemy and, at the same time, for solving the socio-economic problems of the population living in this territory and internally displaced persons from occupied and particularly dangerous regions. After all, the war caused large-scale destruction of civil infrastructure, a humanitarian catastrophe, and has devastating economic consequences. The authors have made an attempt to summarize the measures regarding the organization of the budget process in the conditions of martial law, which were taken by the central bodies of executive power of various levels in order to reduce the negative impact on the formation of local budgets and the implementation of operational management of the formation of resources of territorial communities. These measures are classified according to the areas that have the greatest impact on local finances, such as tax, social and budgetary policy. It was emphasized that as a result of the listed measures implementation, the central governmental bodies in Ukraine managed to create a certain environment that contributes to the protection of the sphere of local finances and forms the basis for its stability in the conditions of modern uncertainty. However, it is clear that despite the state of war, every community needs to take measures to balance local budgets and find reserves to fill local budgets by attracting new sources and using existing funds effectively. The authors express the opinion that in the process of finding new sources for replenishing local budgets, first of all, it is necessary to pay attention to the potential of internally displaced persons, to the possibility of attracting enterprises to relocation, providing production sites, especially to enterprises that have lost production in the south and east of the country, etc. Optimization of the expenditure part of local budgets, according to the authors, is possible due to the suspension of funding of those measures that do not contain a strategic component of improving the security of the territorial community.

Simulation Analysis of Ammonia Leakage and Dispersion in a Large-Scale Refrigeration System

The use of ammonia in large-scale refrigeration systems (such as those used for a stadium) requires adequate ammonia leakage prevention mechanisms are put in place. In the present study, numerical simulations have been conducted to study the dispersion law in the ammonia machinery room of the refrigeration system for the 2022 Beijing Winter Olympics. The wind speed, and release location have been varied to investigate their effects on the dispersion profile. Different positions of the leakage points in the ammonia storage tank have been found to lead to different areas affected accordingly. In general, the dangerous region area decreases with an increase in the wind speed. However, when the wind is aligned with the leakage direction, this trend is reverted. The study may offer an effective method to predict the impact of ammonia dispersion and implement the safe operation of such large-scale systems.

CONTROLLING THE PARAMETRIC ROLL OF A CONTAINER SHIP MODEL BY CHANGING THE HEADING ANGLE

Parametric roll on ships is an auto-parametric resonance phenomenon whose onset causes a sudden rise in roll oscillations leading to dangerous situations for the ship, the cargo and the crew. In the paper, we have numerically investigated the effect of modifying the heading angle on the roll amplitudes. We followed three strategies. In the first, we allowed the heading angle to decrease with a constant angular acceleration so that the encounter frequency has left the dangerous region of the resonance. However, this option involves changing the course of the ship in the long run, which is of course a shortcoming. In the second strategy, we changed the heading angle up and down around an average value that generates large roll amplitudes, by using different periodic sinusoidal or triangular profiles. The beneficial effect of this action is to keep the course, even if at the cost of a momentary delay. We noticed that both control techniques listed above generally managed to significantly reduce the roll amplitudes if certain thresholds have been exceeded. As a last idea for decreasing the parametric roll amplitudes, we used the combined effect of ship forward speed and heading angle change.

Smart border patrol using drones and wireless charging system under budget limitation

Harsh environmental factors surrounding the national borders as well as their extensive length make the use of manned systems for monitoring every location on the border a risky, expensive, and hardly possible task. Smart border patrol using small-size drones may provide significant help in patrolling areas inaccessible to patrol agents, reduce agent response time, and increase the safety of patrol agents working in dangerous regions. However, the short flight duration associated with small-size drones due to battery limitation can be a serious drawback for such a system for seamless surveillance. Therefore, this paper proposes a drone-based continuous surveillance system for border patrol with a dynamic wireless battery charging system that is built onto an electrification line (E-line). To control the maximum time interval between two consecutive flights to a particular section of the border, a permitted revisiting gap is assigned to each location on the border based on its criticality. A multi-objective mixed-integer non-linear programming (MINLP) model is developed to minimize both the total length of the E-line system for the wireless charging system and the number of drones to satisfy the revisiting gap constraint for a secure border patrol. A solution algorithm is proposed to achieve the Pareto-optimal set. This method provides the decision-maker with a set of candidate solutions to choose from based on their priorities and budgetary constraints. We illustrate our method using a case study on a segment of the US-Mexico borderline.

Trajectory planning of autonomous mobile robots applying a particle swarm optimization algorithm with peaks of diversity

This paper presents a new quantum-behaved particle swarm optimization (QPSO) algorithm for the trajectory planning task of mobile robotic vehicles in static and dynamic environments—it is called enhanced diversity particle swarm optimization (EDPSO). The main characteristic of this algorithm is that it has peaks of diversity in its population, making it possible to escape from local minima effectively, avoiding stagnation. Through the proposed PSO, it is possible to obtain safe and efficient routes, avoiding energy waste and maintaining system integrity in several possible applications. The parameters of the proposed algorithm were tuned using the benchmarking functions. The same functions were used to compare the algorithm with those already established in the literature. Once the proposed algorithm showed promising results, it was simulated in four environments, each with different complexities, presenting dangerous regions and terrains unsuitable for robot navigation, and a large number of obstacles or even moving objects. Further, the algorithms used for comparison were also simulated and the EDPSO presented satisfactory results. Through simulations it was possible to notice that the proposed approach resulted in collision-free and planned routes, and the algorithm presented increased exploration features owing to the diversity peaks that occur during the optimization.

Thermo-structural behavior of thermal barrier coatings for thrust chamber applications

The investigation of the failure mechanism is essential for the application of thermal barrier coating in the thrust chamber of liquid rocket engines. In this work, a four-layer thermal barrier coating system in a typical regeneratively-cooled thrust chamber was simulated by finite element method, and the interface morphology between layers was represented by an ideal cosinusoidal curve. A thermo-structural analysis, the boundary conditions of which were calculated by a fluid-thermal coupling method, was carried out to study the influence of the interface roughness and thermally grown oxide on the temperature and stress distributions under thermal cycles. Elasto-plastic deformation and creep behavior were also taken into consideration. The computed results reveal that the roughness parameters including interface amplitude and wavelength as well as the thermally grown oxide thickness have limited effects on the temperature distribution in the thrust chamber wall, but a significant impact on the residual stress distribution in thermal barrier coatings. As these parameters grow, the magnitude of residual stress generally increases, meanwhile, the dangerous regions transform in a complicated way. Much attention should be paid to the interface of thermal barrier coatings in thrust chambers.

Numerical study of tornado-borne debris on a low-rise building through large eddy simulation

Tornado-borne debris is considered as a major source of damage. However, effects of tornado-borne debris on buildings have been seldom investigated. This study performed large eddy simulation to reproduce a tornado and examined the characteristics of incident debris on building surfaces, considering two factors: debris diameter (d=2, 5, and 10 cm), and distance between tornado center and building (r). The debris was assumed to be wooden. It has been found that the probability of the debris hitting the building is the highest when d=5 cm, and the debris mainly hit the windward surface and the far-tornado lee-side wall of the building. The downward flying debris is the reason of relatively high intensities of the debris hitting the building roof when r=0. The highest speed of the debris hitting the building occurs when the building is mounted at the core boundary of the tornado, reaching 126 m/s. In addition, interaction between the tornado and building disturbs and accelerates the flying debris. The windward wall of the building experiences the strongest debris hit, with the maximum hitting speed of 102 m/s, 126 m/s, and 188 m/s, when the debris diameter is 2, 5, and 10 cm, respectively. The most dangerous region is identified as the near-core part of windward building surface.

An Improved Method for Automatic Identification and Assessment of Potential Geohazards Based on MT-InSAR Measurements

Multi-temporal Interferometric Synthetic Aperture Radar (MT-InSAR) has been widely used for ground motion identification and monitoring over large-scale areas, due to its large spatial coverage and high accuracy. However, automatically locating and assessing the state of the ground motion from the massive Interferometric Synthetic Aperture Radar (InSAR) measurements is not easy. Utilizing the spatial-temporal characteristics of surface deformation on the basis of the Small Baseline Subsets InSAR (SBAS-InSAR) measurements, this study develops an improved method to locate potential unstable or dangerous regions, using the spatial velocity gradation and the temporal evolution trend of surface displacements in large-scale areas. This method is applied to identify the potential geohazard areas in a mountainous region in northwest China (Lajia Town in Qinghai province) using 73 and 71 Sentinel-1 images from the ascending and descending orbits, respectively, and an urban area (Dongguan City in Guangdong province) in south China using 32 Sentinel-1 images from the ascending orbit. In the mountainous area, 23 regions with potential landslide hazards have been identified, most of which have high to very high instability levels. In addition, the instability is the highest at the center and decreases gradually outward. In the urban area, 221 potential hazards have been identified. The moderate to high instability level areas account for the largest proportion, and they are concentrated in the farmland irrigation areas, and construction areas. The experiment results show that the improved method can quickly identify and evaluate geohazards on a large scale. It can be used for disaster prevention and mitigation.

Optimizing the Flight Route of UAV Using Biology Migration Algorithm

Optimizing the flight trajectory unmanned aerial vehicles (UAVs) is always a popular optimization problem in computation intelligence field, which aims to search optimal flight path for avoiding detection and complementing some highly difficult missions in complex military environments. This paper mainly utilizes a recent proposed biology migration algorithm (BMA) inspired by the species migration mechanism for dealing with the UAV trajectory optimization problem. The main goal of the UAV model is to search feasible parameters including the flight angle, coordinates and distance for minimizing the flight price computed based on the threat and fuel costs. As one of swarm intelligence techniques, BMA has the characteristics of self-organization, fast convergence and self-adaption in the optimization process, So, it is able to find a safe flight route between the start point and target point while avoiding the dangerous regions and minimum cost. Simulation experiments show that BMA can generate promising and better results with respective to other compared algorithms.