With the global increase in maritime activities, the frequency of maritime accidents has risen, underscoring the urgent need for faster and more efficient search and rescue (SAR) solutions. This study presents an intelligent unmanned aerial vehicle (UAV)-based maritime rescue system that combines GPS-driven dynamic path planning with vision-based dual-target detection and tracking. Developed within the Gazebo simulation environment and based on modular ROS architecture, the system supports stable takeoff and smooth transitions between multi-rotor and fixed-wing flight modes. An external command module enables real-time waypoint updates. This study proposes three path-planning schemes based on the characteristics of drones. Comparative experiments have demonstrated that the triangular path is the optimal route. Compared with the other schemes, this path reduces the flight distance by 30–40%. Robust target recognition is achieved using a darknet-ROS implementation of the YOLOv4 model, enhanced with data augmentation to improve performance in complex maritime conditions. A monocular vision-based ranging algorithm ensures accurate distance estimation and continuous tracking of rescue vessels. Furthermore, a dual-target-tracking algorithm—integrating motion prediction with color-based landing zone recognition—achieves a 96% success rate in precision landings under dynamic conditions. Experimental results show a 4% increase in the overall mission success rate compared to traditional SAR methods, along with significant gains in responsiveness and reliability. This research delivers a technically innovative and cost-effective UAV solution, offering strong potential for real-world maritime emergency response applications.
The attitude controller design for the underactuated rigid spacecraft is addressed by considering that there are only 2 reaction wheels in the spacecraft. Most of the existing attitude control methods for underactuated spacecraft suffer from long system state convergence times and large overshoots. To improve the rapidity and stability of the attitude control system, in this paper, the predefined-time control technique is investigated for solving the attitude stabilization control issue for the underactuated spacecraft for the first time. By combining the sliding control method, a kind of predefined-time attitude stabilization control scheme is developed for the underactuated spacecraft. It is shown that the attitude variables and the angular velocity of the underactuated spacecraft are convergent into 2 non-empty sets within a predefined time by theoretical analysis. The simulation results illustrate the predefined-time convergence of the presented control scheme. In addition, the advantages of the proposed control strategy in this paper are demonstrated by comparing it with some existing control methods.
Motor vehicles. Aeronautics. Astronautics, Astronomy
A tethered towing system provides an effective method for capturing pieces of space debris and dragging them out of orbit. This paper focuses on the in-plane stability analysis and libration control of a two-segment tethered towing system. The first segment is the same as the traditional single-tether towing system. The second segment is similar to a simplified space tether net. The dynamic equations are established in the orbit frame. Considering the elasticity of the tethers, the equilibrium solutions are obtained and the stability of equilibrium solutions is proved. An in-plane libration controller based on the sliding mode control scheme is designed to ensure the safety of the towing mission and save fuel. The controller suppressed the librations of the in-plane angles in the desired state by applying two external torques. Finally, simulation results are provided to validate the effectiveness of the proposed controller.
Vladislav T. Todorov, Dmitry Rakov, Andreas Bardenhagen
Disruptive technologies and novel aircraft generations represent a potential approach to address the ambitious emission reduction goals in aviation. However, the introduction of innovative concepts is a time-consuming process, which might not necessarily yield an optimal design for a given flight mission and within the defined time frame. In order to address the need for a structured and more exhaustive search for novel concept generations, the Advanced Morphological Approach (AMA) and its further enhancement was introduced earlier. It implies the decomposition of design problems into functional attributes and appropriate technological alternatives. Subsequently, these are evaluated and combined into solutions, which are then projected onto a solution space. The current paper focuses on the technology evaluation step by deriving and integrating structured expert judgment elicitation (SEJE) techniques into conceptual aircraft design with the AMA. For this purpose, the first aim of the work is to justify the developed method by giving an overview and discussing the most prominent SEJE methods and their applications in aerospace. Then, the derived SEJE concept is described and applied in the form of an expert workshop on the use case of wing morphing architecture. As a result, a solution space of wing morphing architecture configurations is generated and analyzed. The workshop conduction and the expert feedback serve as valuable findings for both the further AMA enhancement and similar research.
Gas flow in the seal system can be expected during the operation of a turbocharger and is associated with negative effects on the quality of the lubricant or turbocharger efficiency. Gas flow also affects particulate matter production due to lubricant entrainment in the compressor or turbine. The prediction of gas flow rates depends on many design parameters and the operating conditions of the turbocharger, but sufficiently accurate descriptions of the gas flow mechanisms and their quantification depending on the operating conditions have not yet been presented. The proposed computational approach simultaneously solves the gas dynamics in the seal system, the heat transfer in the turbocharger rotor-bearing system and the dynamics of the seal rings and rotor, including the bearings. The computational model for the turbocharger of a heavy-duty vehicle engine is experimentally validated. Two mechanisms have major influences on gas mass flow: the gas flow through the thin gap between the moving ring and groove and the flow through the ring gap. The results show that the importance of these mechanisms depends on several geometrical dimensions of the seal system and the operating conditions of the turbocharger, with a strong connection to the rotor dynamics and thermal load of the impellers. Influences involving rotor movement or rotor thermal conditions are crucial, and their non-inclusion limits the ability to correctly predict gas mass flow.
The SHELL (Software, Hardware, Environment, Liveware) model is one
of the models for determining the cause of aviation accidents. The human factors of
medical accidents are analyzed through the SHELL model. This study is a case study
that analyzed a total of three cases, including two medical accident court precedents
and one large fire at a medical institution. In the human factor analysis of cases 1
and 2, the main factors were that liveware (human) violated the duty of care and did
not follow the guidelines of the institution. The large fire incident in the hospital in
Case 3 was caused by a lack of awareness of the safety of managers, the installation
of illegal facilities and environments, lack of medical staff’s response and training,
and the condition of patients who were mostly elderly. The liveware at the center of
the SHELL model is the most important human factor, and the environment, facilities,
and equipment surrounding liveware must be supplemented to prevent future medical
accidents.
Victor V. Kuzenov, Sergei V. Ryzhkov, Aleksey Yu. Varaksin
This paper provides an overview of modern research on magnetoplasma methods of influencing gas-dynamic and plasma flows. The main physical mechanisms that control the interaction of plasma discharges with gaseous moving media are indicated. The ways of organizing pulsed energy input, characteristic of plasma aerodynamics, are briefly described: linearly stabilized discharge, magnetoplasma compressor, capillary discharge, laser-microwave action, electron beam action, nanosecond surface barrier discharges, pulsed spark discharges, and nanosecond optical discharges. A description of the physical mechanism of heating the gas-plasma flow at high values of electric fields, which are realized in high-current and nanosecond (ultrafast heating) electric discharges, is performed. Methods for magnetoplasma control of the configuration and gas-dynamic characteristics of shock waves arising in front of promising and advanced aircraft (AA) are described. Approaches to the control of quasi-stationary separated flows, laminar–turbulent transitions, and static and dynamic separation of the boundary layer (for large PA angles of attack) are presented.
Background. The geological conditions of the Russian site for deep burial of radioactive waste near
the Yenisei are considered. Not only isolated within the boundaries of a given site, as was the case before. But also
taking into account more ambitious factors: tectonics of lithospheric plates, properties of a number of functionally
similar sites in transitional conditions (Baltic–Yenisei–Pacific Ocean), zoning of the local adjacent territory by mineral
resources, the presence of other disposal facilities near the site. Materials and methods. In such a semantic connection,
it is proposed to study at the exploration stage the main engineering-geological parameter of the rock mass for safety – the state of the underground hydrosphere. The need reliable regulatory and legal framework was noted. Results
and conclusions. Based on the results of the initial stages of work on the deep disposal site for radioactive waste,
shortcomings in the application and implementation of legislation and technical standards were identified. A proposal
has been formulated for a legal examination of documents prepared for the Yeniseisky site.
Ketan Kotecha, Deepak Garg, Balmukund Mishra
et al.
Visual data collected from drones has opened a new direction for surveillance applications and has recently attracted considerable attention among computer vision researchers. Due to the availability and increasing use of the drone for both public and private sectors, it is a critical futuristic technology to solve multiple surveillance problems in remote areas. One of the fundamental challenges in recognizing crowd monitoring videos’ human action is the precise modeling of an individual’s motion feature. Most state-of-the-art methods heavily rely on optical flow for motion modeling and representation, and motion modeling through optical flow is a time-consuming process. This article underlines this issue and provides a novel architecture that eliminates the dependency on optical flow. The proposed architecture uses two sub-modules, FMFM (faster motion feature modeling) and AAR (accurate action recognition), to accurately classify the aerial surveillance action. Another critical issue in aerial surveillance is a deficiency of the dataset. Out of few datasets proposed recently, most of them have multiple humans performing different actions in the same scene, such as a crowd monitoring video, and hence not suitable for directly applying to the training of action recognition models. Given this, we have proposed a novel dataset captured from top view aerial surveillance that has a good variety in terms of actors, daytime, and environment. The proposed architecture has shown the capability to be applied in different terrain as it removes the background before using the action recognition model. The proposed architecture is validated through the experiment with varying investigation levels and achieves a remarkable performance of 0.90 validation accuracy in aerial action recognition.
Ablative-cooled hybrid rockets could potentially combine a similar versatility of a liquid propulsion system with a much simplified architecture. These characteristics make this kind of propulsion attractive, among others, for applications such as satellites and upper stages. In this paper, the use of hybrid rockets for those situations is reviewed. It is shown that, for a competitive implementation, several challenges need to be addressed, which are not the general ones often discussed in the hybrid literature. In particular, the optimal thrust to burning time ratio, which is often relatively low in liquid engines, has a deep impact on the grain geometry, that, in turn, must comply some constrains. The regression rate sometime needs to be tailored in order to avoid unreasonable grain shapes, with the consequence that the dimensional trends start to follow some sort of counter-intuitive behavior. The length to diameter ratio of the hybrid combustion chamber imposes some packaging issues in order to compact the whole propulsion system. Finally, the heat soak-back during long off phases between multiple burns could compromise the integrity of the case and of the solid fuel. Therefore, if the advantages of hybrid propulsion are to be exploited, the aspects mentioned in this paper shall be carefully considered and properly faced.
The paper assumes a Bayesian estimate of the telecommunication systems availability ratio. Downtime and uptime are described by gamma distributions with positive integer parameters. Estimates of the distribution parameters are obtained using the maximum likelihood method. For the set samples, the values of the desired probability distribution densities are found and an expression for estimating the availability ratio is derived. Numerical estimates for the standard and assumed estimates are given. For a system with two states, a Bayesian estimate of the availability function with consideration of downtime and serviceable condition takes into account the features of backup equipment and the effect of its failure defined by performance reliability and features that ensure the reliability of information signals. The proposed Bayesian approach has the following advantages: it is possible to conduct quantitative estimates with lack of sufficient statistics on functional use indicators; it takes into account all destabilizing factors of various nature; the presence of a lower mean square error compared to traditional methods. To implement the proposed approach that estimates the availability ratio, confidence probabilities are introduced relative to the indicator of failure flows and equipment recovery. The parameters of the a priori information can be determined by different methods or on the basis of sufficient statistical data. To illustrate the discussed calculation algorithm, a digital data transmission system of a standard satellite navigation system consisting of terminal, radio equipment, and a transponder is considered. To estimate the required values, we used data on interruptions in the operation of equipment due to its malfunction during a conditional year. The frequency of downtime caused by signal propagation conditions and equipment failures was evaluated. It was shown that the gamma distribution is suitable for describing the frequency distribution of downtime. The frequency distribution of the cyclicity coefficient with the condition of the selected time interval was also taken into account. Sample mathematical expectations and mean square deviations of the downtime coefficient were found. As a result, the numerical example shows the correctness of using the Bayesian estimate of weighted equipment preparedness.
Khrulev Alexander E., Saraiev Olexii V., Saraieva Irina
Problem. The main trends in the car gasification are considered. It is shown that after the global automakers lost the interest in the creation and production of gas engines, the development of gas systems continues in the secondary market. A noticeable decrease in the valve train durability due to the valve recession was noted, which can make the conversion of the engine to gas fuel technically inexpedient and economically ineffective. However, in practice, a detailed economic analysis is either not carried out at all, or is done in a simplified manner. Goal of the work is to develop a methodology and obtain the quantitative data that allow assessing the economic efficiency and technical feasibility of converting the gasoline engines to gas engine fuel. Methodology includes the analysis of the friction process in the valve-seat interface zone using semi-empirical methods. Based on the data obtained, a list of constructive measures was compiled to reduce wear when converting the gasoline engine to gas fuel. A method for calculating the economic efficiency of a gasoline engine operating on gas, taking into account the initial and operating costs, has been developed. Results. It is noted that the transfer of a serial gasoline engine to gas without making changes to the valve train design means an absolutely inevitable decrease in the resource of the valve-seat interface. The area of effective application of gas equipment in car transport is obtained by calculation. It is shown that despite the large difference in price between gasoline and gas, the total economic effect of converting a gasoline engine to gas fuel does not exceed 15-20% and in general has a number of serious limitations not only of an economic but also of a technical nature. Originality. For the first time, it has been shown that any options for unauthorized conversion of car engines to another fuel should be considered, first of all, in terms of economic efficiency over the entire service life of the car, and not as private advantages obtained during certain periods of its operation. Practical value. The results obtained can be used in practice in the development of transport gasification programs, in assessing the real economic efficiency of the use of gas cylinder equipment, as well as in the search for the faults caused by the engine design change if converting it to another fuel.
The aerodynamic characteristics of a NACA0012 wing geometry at low Reynold’s numbers and angle of attack ranging from 0º to 90º are investigated using numerical simulations and the results are validated by wind tunnel experiments. Further experiments are conducted at low Reynold’s numbers of 1 × 105, 2 × 105 and 3 × 105. Findings of the study show a similar trend for the lift and drag coefficients at all the investigated Reynold’s numbers. The lift coefficient is linearly increased with angle of attack until it reaches its maximum value at 32º which is the stall angle. It is observed that further increment in angle of attack results in decrement of lift coefficient until it reaches its minimum value at 90º angle of attack. The drag force acting on the airfoil increases as the angle of attack is increased and increment in the drag force results in change of laminar flow to turbulent flow. As the turbulence gets higher the flow starts to separate from the airfoil surface due to eddies generated by turbulence. Hence, the lift force generated by the wing is reduced and drag force is increased simultaneously, which results in poor performance of the wing.
Technology, Motor vehicles. Aeronautics. Astronautics
Henning Teickner, Jan R. K. Lehmann, Patrick Guth
et al.
In ecological research, a key interest is to explore movement patterns of individual organisms across different spatial scales as one driver of biotic interactions. While various methods exist to detect and record the presence and movements of individuals in combination with UAS, addressing these for smaller animals, such as insects, is challenging and often fails to reveal information on potential interactions. Here, we address this gap by combining the UAS-based detection of small tracers of fluorescent dyes by means of a simple experiment under field conditions for the first time. We (1) excited fluorescent tracers utilizing an UV radiation source and recorded images with an UAS, (2) conducted a semi-automated selection of training and test samples to (3) train a simple SVM classifier, allowing (4) the classification of the recorded images and (5) the automated identification of individual traces. The tracer detection success significantly decreased with increasing altitude, increasing distance from the UV radiation signal center, and decreasing size of the fluorescent traces, including significant interactions amongst these factors. As a first proof-of-principle, our approach has the potential to be broadly applicable in ecological research, particularly in insect monitoring.
Trailing edge surface of aerofoil is an important source of broadband aerodynamic noise production. In this
paper, three aerofoil self-noise mechanisms from turbulent boundary layer near trailing edge surface are studied. Numerical
computations were performed for a three bladed 2 MW horizontal axis upwind turbine of blade length 37 m and source height
of 80 m, for wind speeds of 8-15 m/s. A weighted 1/3rd octave band sound power levels (SPL) are evaluated for receiver
located at distance of total turbine height and at 2 m above ground. The results obtained for sound power level using baseline
models showed maximum values occurring between 300 Hz and 1 kHz region of spectrum. The trends for BPM model showed
a reduction of ~2 dBA near 1 kHz region of spectrum at 10 m/s, but Grosveld’s and Lowson model were identical and agreed
over the entire spectrum. The effect of rotational speed on sound power levels using three baseline models are illustrated at a
wind speed of 8 m/s for 2 MW turbine. Results showed that for a change of ±10% rotor speed from the rated value, there is
an increase of 2 to 6 dBA over the entire sound spectrum due to differences in blade tip speed.
Technology, Motor vehicles. Aeronautics. Astronautics
Leonardo Juan Ramírez López, Andrés Fernando Marín López, Arturo Rodríguez García
La Enfermedad Pulmonar Obstructiva Crónica – EPOC, corresponde a las diversas dolencias pulmonares crónicas que limitan el flujo de aire en los pulmones. Actualmente, presenta un importante aumento en su prevalencia y mortalidad a nivel mundial, siendo actualmente, según la Organización Mundial de la Salud, la cuarta causa de mortalidad en el mundo, donde más del 90 % de estas muertes se producen en países de bajos y medianos ingresos. En Colombia es la cuarta causa de muerte, llegando en el 2016 a 38 muertes diarias. Por esto, el Plan Decenal de Salud Pública 2012-2021, establece las intervenciones que deben ser implementadas desde la prevención, detección temprana, tratamiento y rehabilitación. Esta investigación propone la implementación del Internet de las Cosas en una solución costo- efectiva para el monitoreo de esta enfermedad, mediante la medición constante de la temperatura corporal, saturación de oxígeno y frecuencia cardíaca con sensores de bajo costo que permitan analizar y emitir alarmas de prevención temprana. Los resultados permiten afirmar que todas las medidas realizadas con el Sistema IoT desarrollado permanecen en el intervalo de confianza de los equipos tomados como referencia.
Motor vehicles. Aeronautics. Astronautics, Military Science
It should be noted that a number of countries consider that the Arctic is the property of all mankind and therefore the legal regime of the usage of this region territory is necessary to be reconsidered. The intensification of the armed forces activities on the northern borders is caused by aggravated international disagreements on the issues of territorial influence in this region, by the need to ensure the safety of increasing freight traffic through the Northern Sea Route and also by an increase in production capacities of domestic extractive enterprises on the shelf. The article deals with the challenge of the accelerated development in the Arctic region of Russia. It is noted that the major role in the solution of this problem belongs to an air-transport complex which is almost the only means to provide the operational availability to objects in the region. For the effective usage of the air-transport complex the approach based on the concept of radio-technical flight support, founded on the technologies of global navigation satellite systems and automatic dependent observation is offered. The existence of readymade technical solutions for these technologies implementation allows to accelerate the solvation of social and economic development problems of the Arctic region in general, alongside with the problems of national security of Russia.
To minimize the cost and maximize the ease of use, a class of dual-spin mortars is designed which only rely on GPS receiver and geomagnetic measurements. However, there are some problems to be solved when the range is small, such as low correction authority and trajectory bending. Guidance law design for this mortar is detailed. Different guidance laws were designed for the ascending and descending segments, respectively. By taking variable parameter guidance law in the vertical plane and using compensation in the lateral plane, the problems mentioned above were resolved. Roll angle resolving algorithms with geomagnetic measurements were demonstrated and the experiment results proved to be effective. In order to verify the effectiveness, Seven-Degrees-of-Freedom (7-DOF) rigid ballistic model were established and hardware in the loop simulation was introduced. After the transform function of the actuator was obtained, the control model of the shell was improved. The results of the Monte Carlo simulation demonstrate that the guidance law is suitable and the mortar can be effectively controlled.