Aiming at the difficulty of trajectory prediction caused by the changing motion mode of hypersonic glide vehicle and the short prediction window, the trajectory characteristics of hypersonic glide vehicle under typical mission scenarios are analyzed, and an intelligent trajectory prediction algorithm based on intention information is proposed. Firstly, the conversion formula for identifying control parameters of hypersonic glide vehicle under radar system is derived. Then, the influence of intention on hypersonic glide vehicle control parameters is analyzed from the defense point of view, and the core influencing factors are determined such as the approach speed, course angle deviation and tangential distance from the center of the nearest no-fly zone. Finally, taking core factors, historical control parameters and historical location information as characteristic values, the future trajectory of hypersonic glide vehicle is predicted by introducing sequence-to-sequence deep learning model of attention mechanism. The simulation results show that the trajectory prediction algorithm designed in this paper has better accuracy than traditional trajectory prediction algorithm that only use position information.
Wireless charging for drones is significant for solving problems such as the frequent manual plugging and unplugging of cables. A large number of densely packed transmitting coils and fully independent on-off control can precisely track the receiver with random access location. To balance the excitation area of the transmitter, additional hardware cost, and receiving voltage fluctuation, the wireless charging system of drones based on a D3-type transmitter is proposed in this article. The circuit model considering states of multiple switches is developed for three excitation modes. The dual-coil excitation mode is selected after comparative analysis. The transmitter reconfiguration method with low hardware cost and high receiving-excitation area ratio is proposed based on one detection sensor of DC current and one relay furtherly. Finally, an experimental prototype is built to verify the theoretical analysis and proposed method. When the output voltage fluctuation is limited to ±10%, the ratios of the maximum misalignment value in the <i>x</i>-axis and <i>y</i>-axis directions to the side length of the receiver reach 66.7% and 46.7%, respectively. The receiving-excitation area ratio of 37.5% is achieved, significantly reducing the excitation area not covered by the receiver. The maximum receiving power is 289.44 W, while the DC-DC efficiency exceeds 87.05%.
High-fidelity simulations are used to study the stability of a coupled parachute–payload system in different configurations. A 8.53 m ring–slot canopy is attached to two separate International Organization for Standardization (ISO) container payloads representing a Twenty Foot Equivalent (TEU). To minimize risk and as an alternative to a relatively expensive traditional test program, a multi-phase design and evaluation program using computational tools validated for uncoupled parachute system components was completed. The interaction of the payload wake suspended at different locations and orientations below the parachute were investigated to determine stability characteristics for both subsonic and supersonic freestream conditions. The DoD High-Performance Computing Modernization Program CREATE<sup>TM</sup>-AV Kestrel suite was used to perform CFD and fluid–structure interaction (FSI) simulations using both delayed detached-eddy simulations (DDES) and implicit Large Eddy Simulations (iLES). After analyzing the subsonic test cases, the simulations were used to predict the coupled system’s response to the supersonic flow field during descent from a high-altitude deployment, with specific focus on the effect of the payload wake on the parachute bow shock. The FSI simulations included structural cable element modeling but did not include aerodynamic modeling of the suspension lines or suspension harness. The simulations accurately captured the turbulent wake of the payload, its coupling to the parachute, and the shock interactions. Findings from these simulations are presented in terms of code validation, system stability, and drag performance during descent.
The Lunar Augmented Navigation Service (LANS) is the lunar equivalent of GNSS for future lunar explorations. It offers users accurate position, navigation, and timing (PNT) capabilities on and around the Moon. The Augmented Forward Signal (AFS) is a standardized signal structure for LANS, and its recommended standard was published online on 7 February 2025. This work presents software-defined radio (SDR) implementations of the LANS AFS simulator and receiver, which were rapidly developed within a month of the signal specification release. Based on open-source GNSS software, including GPS-SDR-SIM and Pocket SDR, our system provides a valuable platform for future algorithm research and hardware-in-the-loop testing. The receiver can operate on embedded platforms, such as the Raspberry Pi 5, in real-time. This feature makes it suitable for lunar surface applications, where conventional PC-based SDR systems are impractical due to their size, weight, and power requirements. Our approach demonstrates how open-source SDR frameworks can be rapidly applied to emerging satellite navigation signals, even for extraterrestrial PNT applications.
Sarah Rebecca Ondraszek, Jörg Waitelonis, Katja Keller
et al.
An essential component for evaluating and comparing physical and cognitive capabilities between populations is the testing of various factors related to human performance. As a core part of sports science research, testing motor performance enables the analysis of the physical health of different demographic groups and makes them comparable. The Motor Research (MO|RE) data repository, developed at the Karlsruhe Institute of Technology, is an infrastructure for publishing and archiving research data in sports science, particularly in the field of motor performance research. In this paper, we present our vision for creating a knowledge graph from MO|RE data. With an ontology rooted in the Basic Formal Ontology, our approach centers on formally representing the interrelation of plan specifications, specific processes, and related measurements. Our goal is to transform how motor performance data are modeled and shared across studies, making it standardized and machine-understandable. The idea presented here is developed within the Leibniz Science Campus ``Digital Transformation of Research'' (DiTraRe).
Gino Rodrigo Lavagnino Sanchez, Odenir de Almeida, Fernando Martini Catalano
Small multirotor unmanned aerial systems (sUAS) have become more accessible and efficient recently, spurring their development for various personal and commercial uses. However, this rapid evolution raises concerns about security, control, and public health due to the proliferation of noisy drones. This study focuses on investigating a major noise source in drones called rotor-airframe interaction, which generates tonal noise through pressure fluctuations and wake interactions. To address this issue, we designed and tested three airframes with varying arm configurations. High-definition microphones and data acquisition systems were employed to measure pressure levels, and MATLAB code helped analyze the data as A-weighted signals to identify noise reduction possibilities. The key finding was that motor noise was a significant contributor, producing multiple pure tones at mid and high frequencies. Additionally, the noise signature was heavily influenced by the arm’s geometric shape and angles, underscoring the complex nature of rotor-airframe flow and acoustic interactions.
Technology, Motor vehicles. Aeronautics. Astronautics
Noora A. Hashim, Rasha Hayder Hashim, Fatima Mohammed K. Al-Fatlwe
et al.
Recently, solar energy has become most favorable source of energy. It is sustainable and environmentally friendly, and one of the most common application of solar energy is the solar water heater, which has a wide commercial and domestic applications. To enhance the performance of this device, many modifications are recommended. The enhancements may involve changes in pipe shape or materials or in absorber plate manufacturing, or sometimes by using a thermal storage tank to maintain heating. In this study, a variable cross-sectional area pipe is used to enhance heat transfer. Firstly, the vertical length is increased at the outlet to 1.2-1.8 ratios, while the horizontal sides remain constant. Then, for the same ratio, the horizontal sides are varied while the vertical sides remain constant. Finally, both the vertical and horizontal sides are increase. A three-dimensional numerical analysis is used to investigate the conjugated heat transfer and the flow characteristics in the pipe under study for each case. FLUENT ANSYS 17.2 is used to achieve this analysis using finite volume technique. Energy, Navier-Stokes, and continuity equations are solved at constant heat flux condition for a range of Reynolds numbers from 100 to 500. The hydraulic-thermal function ε is adopted in this study. The best increase in ε is 48%, achieved in the case of changes to both vertical and horizontal dimensions at a ratio of 1.8. The lowest percentage of decrease in pressure drop is 9.7%, and the highest temperature difference found is and 45.5% for the same case when compared with the uniform case for Reynolds number of 100. The present work is validated with another study adopting Shah’s empirical relation with a very good agreement.
Technology, Motor vehicles. Aeronautics. Astronautics
The consequences of emergencies in aviation are significant fatalities and considerable material damage. Ensuring the safety of transport infrastructure facilities is an important strategic task for both the State and the operating organizations. The aviation accident statistics show that for the period from 1950 to 2019 there were 614 occurrences (57% of the total number) due to the human factor (from malice to piloting errors), which actualizes the human-factor problem in the operation and safety of aviation transport. According to the ICAO data, 210 accidents occurred and 641 people were killed in the period 2019–2021. The task of the Aviation Security Service (ASS) employees is the proper performance of duties to ensure safety, prevent abnormal and emergency situations. The assigned duties impose special responsibility on the ASS employees and predetermine their compliance with the specified criteria. The personnel work carried out by the personnel departments of the airlines is aimed at selecting the most appropriate candidates for a position. The article considers the problem of selecting candidates as a task of multi-criteria assessment and selection, where the elements are the criteria (qualities) of a candidate, and their weighted assessments are set by experts. The existing methods of personnel selection in the ASS and the issue of choosing the candidates, who are the most balanced in their personal, qualification and other requirements, are considered. A method of selecting personnel in the ASS is proposed by the method of threshold aggregation of a non-compensatory nature, which has significant advantages over common selection methods by summing points and calculating the arithmetic mean. The results of the study are confirmed by the practical personnel selection of candidates for two airlines, as a result of which the group of ASS inspectors in a growing number, selected by using the threshold aggregation method, passed the probation period more successfully than the group selected by using the summation of criteria points. The results presented in the article allow us to consider the threshold aggregation method of candidates for the airline ASS as a promising method of personnel selection, the purpose of which is to improve the quality of air transport safety, which will reduce the risks of accidents, save human lives and prevent significant material damage.
The reward system is one of the fundamental drivers of animal behaviors and is critical for survival and reproduction. Despite its importance, the problem of how the reward system has evolved is underexplored. In this paper, we try to replicate the evolution of biologically plausible reward functions and investigate how environmental conditions affect evolved rewards' shape. For this purpose, we developed a population-based decentralized evolutionary simulation framework, where agents maintain their energy level to live longer and produce more children. Each agent inherits its reward function from its parent subject to mutation and learns to get rewards via reinforcement learning throughout its lifetime. Our results show that biologically reasonable positive rewards for food acquisition and negative rewards for motor action can evolve from randomly initialized ones. However, we also find that the rewards for motor action diverge into two modes: largely positive and slightly negative. The emergence of positive motor action rewards is surprising because it can make agents too active and inefficient in foraging. In environments with poor and poisonous foods, the evolution of rewards for less important foods tends to be unstable, while rewards for normal foods are still stable. These results demonstrate the usefulness of our simulation environment and energy-dependent birth and death model for further studies of the origin of reward systems.
Patricio Arrué, Kaveh Laksari, Nancy Sweitzer
et al.
Background: Aortic stenosis (AS) is the most common acquired valvar disease and is associated with increased risk for frailty. Frailty as a geriatric syndrome is associated with muscle weakness and a compromised autonomic nervous system (ANS) performance in older adults. The purpose of the current work was to assess differences in both motor and ANS performance, and interaction between them, as symptoms of frailty in community dwelling older adults with and without AS. Results: Eighty-six participants were recruited, including 30 with (age=72$\pm$11, 10 non-frail and 20 pre-frail/frail) and 56 without AS (age=80$\pm$8, 12 non-frail and 44 pre-frail/frail). There was a significant difference in UEF motor score between older adults with and without AS (p<0.01, mean values of 0.57$\pm$0.25 and 0.48$\pm$0.23, respectively). Differences in UEF motor score was also observed between the frailty groups (p=0.02, mean values of 0.55$\pm$0.24 and 0.40$\pm$0.20 for pre-frail/frail and non-frail, respectively). CCM parameters showed significant differences between the frailty groups (p=0.02, mean CCM of 0.69$\pm$0.05 for non-frail and 0.54$\pm$0.03 for pre-frail/frail), but not between the AS groups (p>0.70). No significant interaction was observed between frailty and AS condition (p>0.08). Conclusion: Current findings suggest that ANS measures may be highly associated with frailty regardless of AS condition. Combining motor and HR dynamics parameters in a multimodal model may provide a promising tool for frailty assessment
Carlos Calvo Tapia, Ivan Y. Tyukin, Valeriy A. Makarov Slizneva
Social learning is widely observed in many species. Less experienced agents copy successful behaviors, exhibited by more experienced individuals. Nevertheless, the dynamical mechanisms behind this process remain largely unknown. Here we assume that a complex behavior can be decomposed into a sequence of $n$ motor motifs. Then a neural network capable of activating motor motifs in a given sequence can drive an agent. To account for $(n-1)!$ possible sequences of motifs in a neural network, we employ the winner-less competition approach. We then consider a teacher-learner situation: one agent exhibits a complex movement, while another one aims at mimicking the teacher's behavior. Despite the huge variety of possible motif sequences we show that the learner, equipped with the provided learning model, can rewire ``on the fly'' its synaptic couplings in no more than $(n-1)$ learning cycles and converge exponentially to the durations of the teacher's motifs. We validate the learning model on mobile robots. Experimental results show that indeed the learner is capable of copying the teacher's behavior composed of six motor motifs in a few learning cycles. The reported mechanism of learning is general and can be used for replicating different functions, including, for example, sound patterns or speech.
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.
The market of solar-powered Unmanned Aerial Vehicles (UAVs) for defence purposes and drone services is expected to grow by a factor of more than 2 in the next decade. From an aircraft design perspective, the main challenge is the scalability of the proposed architectures, which is needed to increase the payload capabilities. Beside some successful examples of wing-tail UAVs, some newcomers are developing prototypes with tandem-wing architectures, hence enlarging the possible design. The present paper aims to introduce a further step in this direction, taking also the box-wing architecture into account to show how the presence of wing tip joiners can provide benefits from the aeroelastic point of view. UAVs with take-off mass within 25 kg are considered and the main tools adopted are presented. These are an in-house developed Multi-Disciplinary Analysis and Optimization (MDAO) code called SD2020 and the open source aeroelastic code ASWING, both presented together with an assessment of their accuracy by means of higher fidelity numerical results. SD2020 results are presented for the case of small box-wing solar UAVs optimized to achieve the longest endurance, focusing on the strategy implemented to achieve feasible solutions under an assigned set of constraints. Further results are presented for comparable box-wing and tandem-wing UAVs from both the aerodynamic and aeroelastic standpoints. Whereas the aerodynamic advantages introduced by the box-wing are marginal, significant advantages result from the aeroelastic analyses which indicate that, if the joiners are removed from the box-wing configuration, safety margin from flutter speed is halved and the bending-torsion divergence occurs at relatively low speed values.
A gas–solid-coupled sandwich combustion model was established for ammonium perchlorate (AP)/hydroxyl-terminated polybutadiene (HTPB) composite propellant. Numerical simulations were conducted to investigate the influence of the content of AP and the relative position of the coarse AP on the flame structure and the burning rate of the propellant. The results indicated that the overall AP mass fraction has a significant effect on the gas-phase flame temperature and burning rate, and there exists an optimal oxygen-to-fuel ratio that maximizes the burning rate. As the mass fraction of fine AP increased, the premixed flame above the binder matrix gradually took over the dominance of the diffusion flame, and the intensity of the diffusion flame near the interface of coarse AP and binder matrix also increased, resulting in a significant increase in the burning rate. As the mass fraction of fine AP increases from 0% to 70.0%, the average surface temperature increases from 937 K to 1026 K, and the burning rate rises from 0.9 cm/s to 2.7 cm/s. The location of the coarse AP causes the flame tilts to the side with less binder matrix, but it had little effect on the burn rate of the propellant.
This paper proposes a sensorless electromagnetic docking method suitable for micro- and nanosatellites. Based on the circuit model of the electromagnetic docking device, an algorithm for calculating the distance between two satellites on the basis of the high-frequency injection (HFI) method has been developed. In the specific implementation, first, a high-frequency (HF) voltage is injected into one of the two electromagnets; second, the HF currents induced by both electromagnets are measured and their respective root-mean-squares (RMSs) are calculated; third, two RMSs are substituted into a specific formula to obtain a variable carrying distance information; finally, the variable is utilized to calculate the distance estimation using the look-up table interpolation method. This paper presents a closed-loop electromagnetic docking controller which includes an outer distance loop and an inner speed loop and adopts the distance estimation as the feedback. The proposed sensorless electromagnetic docking method is verified by the distance estimation tracking response test and the ground-based docking test. The results indicate that low-impact docking can be achieved under the initial condition that the two satellites have a certain degree of misalignment. The proposed method can be adopted as a primary or as a redundant electromagnetic docking solution for resource-critical micro- and nanosatellites.
Fateh Kaakai, Shridhar "Shreeder" Adibhatla, Ganesh Pai
et al.
We give a first rigorous characterization of Operational Design Domains (ODDs) for Machine Learning (ML)-based aeronautical products. Unlike in other application sectors (such as self-driving road vehicles) where ODD development is scenario-based, our approach is data-centric: we propose the dimensions along which the parameters that define an ODD can be explicitly captured, together with a categorization of the data that ML-based applications can encounter in operation, whilst identifying their system-level relevance and impact. Specifically, we discuss how those data categories are useful to determine: the requirements necessary to drive the design of ML Models (MLMs); the potential effects on MLMs and higher levels of the system hierarchy; the learning assurance processes that may be needed, and system architectural considerations. We illustrate the underlying concepts with an example of an aircraft flight envelope.
Parking road vehicles is one of the most tedious and challenging tasks a human driver performs. Despite the low speeds involved, parking manoeuvres are among the main causes of minor and sometimes major traffic accidents, especially in urban areas where limited parking spaces are available. Furthermore, searching for a parking space wastes time and contributes to unnecessary road occupancy and pollution. This paper is dedicated to the development of an autonomous parking system for on-street parking in urban areas. The system is capable of fully automated parking manoeuvres from drop-off to pick-up zones, thus removing human drivers from the vehicle control loop. The system autonomously navigates to the parking space and parks the vehicle without human intervention. The proposed system incorporates a communication protocol that connects automated vehicles, parking infrastructure, and drivers. Several convenient human–machine interface concepts for efficient system communication and state monitoring have been developed. A methodology for validating the system in real time is proposed, which includes functionality requirements and a description of parallel and perpendicular parking manoeuvres. The proposed pipeline is tested on an electric vehicle platform with automated functions, where successful technological functionality is demonstrated.
Mechanical engineering and machinery, Machine design and drawing
Background. In the last century, about 20 statistical criteria for testing the hypothesis of normal distribution
of data and about 20 statistical criteria for testing the hypothesis of uniform distribution of data were created.
The article considers a method for synthesizing new statistical criteria by multiplying or dividing their output states.
Materials and methods. It is proposed to multiply (divide) the response of the classical almost orthogonal Legendre
polynomial to the response of the classical Vasicek statistical test. Results and conclusions. It is shown that the proposed
procedures allow two new strong statistical tests to be combined with the Vasicek test. The result is a binary
output code with threefold redundancy. Code redundancy folding reduces the probability of occurrence of errors of the
first and second kind by 5 times.
Vehicle Ad-hoc Networks (VANETs) act as the core of vehicular communications and provide the fundamental wireless communication architecture to support both vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communication. Therefore, by leveraging only communication technologies, Connected Vehicles (CVs) can navigate through the dynamic road network. However, such vehicles are still in their infancy but are expected to have a significant impact on safety and mobility such as reducing non-recurrent congestion in case of a vehicle breakdown or other roadway incidents. To evaluate their impacts, this research examines the benefits of having CVs when a vehicle breakdown occurs by developing an intelligent proactive re-routing algorithm. Due to a lack of real-world data, this paper adopts an integrated simulated framework consisting of a V2X (OMNET++) communication simulator and a traffic microscopic simulator (SUMO). The developed algorithm functions such that when a vehicle is broken down within a live traffic lane, the system detects the breakdown, generates warning messages immediately and transmits them to approaching vehicles. Based on the real-time notification, informed vehicles proactively re-route to alternative roads to avoid the breakdown zone. Two scenarios were developed where a breakdown occurs within and outside a junction for both V2X-enabled and disabled systems. Results show that V2X-enabled CV re-routing mechanism can improve traffic efficiency by reducing congestion and enhance traffic safety by smoothing accelerations and decelerations of affected vehicles with low infrastructure costs. The algorithm would be useful to highway agencies (Department for Transport) and vehicle manufacturers in introducing CVs onto existing road networks.