Search Results (633)

With the rapid development of the low-altitude economy, the application of drones in both military and civilian fields has become increasingly widespread. The safety and accuracy of their positioning and navigation have become critical factors in ensuring the successful execution of missions. Currently, GNSS spoofing attack techniques are becoming increasingly sophisticated, posing a serious threat to the reliability of drone positioning. This paper proposes a GNSS spoofing detection and autonomous positioning method for drones operating in mission mode, which is based on visual sensors and does not rely on additional hardware devices. First, during the deception detection phase, the ResNet50-SE twin network is used to extract and match real-time aerial images from the drone’s camera with satellite image features obtained via GNSS positioning, thereby identifying positioning anomalies. Second, once deception is detected, during the positioning recovery phase, the system uses the SuperGlue network to match real-time aerial images with satellite image features within a specific area, enabling the drone’s absolute positioning. Finally, experimental validation using open-source datasets demonstrates that the method achieves a GNSS spoofing detection accuracy of 89.5%, with 89.7% of drone absolute positioning errors controlled within 13.9 m. This study provides a comprehensive solution for the safe operation and stable mission execution of drones in complex electromagnetic environments. Full article

Real-time positioning is a technological field with a multitude of applications, which expand across many scopes: from positioning within a large area to localization within smaller spaces; from locating people to locating equipment; from large-scale industrial or military applications to commercially available solutions. There are at least as many implementations of real-time positioning as there are applications and challenges. Within the domain of Radio Frequency (RF) systems, positioning has been approached from multiple angles. Some of the more common solutions involve using Time of Flight (ToF) and time difference of arrival (TDoA) technologies. Within TDoA-based systems, one common limitation stems from the computational power necessary to run the multi-lateration algorithms at a high enough speed to provide high-frequency refresh rates on the tag positions. The system presented in this study implements a complete hardware and software TDoA-based real-time positioning system, using wireless Ultra-Wideband (UWB) technology. This system demonstrates improvements in the state of the art by addressing the above limitations through the use of a hybrid Machine Learning solution combined with algorithmic fine tuning in order to reduce computational power while achieving the desired positioning accuracy. This study presents the design, implementation, verification and validation of the aforementioned system, as well as an overview of similar solutions. Full article

Flying wing UAVs are widely used in both civil and military areas and they are vulnerable to being affected by multi-source disturbances and actuator faults due to their unique aerodynamic configuration. This paper proposes composite continuous high-order nonsingular terminal sliding mode control controllers for the longitudinal command tracking control of flying wing UAVs. The proposed method guarantees not only the finite-time convergence of command tracking errors, but also the continuity of control actions. Simulation results validate the effectiveness of the proposed method. Full article

Hydraulic actuated legged robots display bright prospects and significant research value in areas such as unmanned area surveying, disaster rescue, military fields, and other scenarios owing to their excellent bionic characteristics, particularly their heavy payload capabilities and high power density. To realize the all-terrain adaptation locomotion of the hydraulic hexapod robot (HHR) with a heavy payload, one alternative control framework is position–posture control based on joint position control. As the foundation for the steady locomotion of HHRs, it is imperative to realize high-precision joint position control to improve the robustness under external disturbances during the walking process and to complete the attitude control task. To address the above issues, this paper proposes a sliding mode repetitive control based on the unknown dynamics estimator (SMRC + UDE) for the knee and hip joints of the HHR with a two-stage supply pressure hydraulic system (TSS). The effectiveness of the SMRC + UDE method is verified using a simulation environment and the ZJUHEX01 prototype experimental platform, and it is compared with the results for PID and adaptive robust sliding mode control (ARSMC). The results show that SMRC + UDE may be more suitable for our HHR, considering both the control performance and efficiency factors. Full article

This paper explores ways to improve the coordinate transformation of maps from the First and Second Military Surveys of the Austro-Hungarian Monarchy using airborne laser scanning (ALS) data. The paper analyses the current positional accuracy of georeferenced maps from the first two military mappings from available spatial data sources. Several areas of interest with different terrain ruggedness (plain, undulated terrain, mountains) were selected for analysis to investigate whether terrain ruggedness has an impact on the accuracy of these maps. The next part of the paper deals with the georeferencing of military mapping maps using current, mid-20th-century maps and ALS data using affine and second-degree polynomial transformations. The paper concludes with a statistical analysis and evaluation of the potential of ALS data for solving this type of problem. The results obtained in the paper indicate that ALS data can be a suitable source for finding control points to transform early topographic maps. Full article

Wireless sensor networks (WSNs) have found extensive applications in a variety of fields, including military surveillance, wildlife monitoring, industrial process monitoring, and more. The gradual energy depletion of sensor nodes with limited battery energy leads to the dysfunction of some of the nodes, thus creating coverage holes in the monitored area. Coverage holes can cause the network to fail to deliver high-quality data and can also affect network performance and the quality of service. Therefore, the detection and recovery of coverage holes are major issues in WSNs. In response to these issues, we propose a method for detecting and recovering coverage holes in wireless sensor networks. This method first divides the network into equally sized units, and then selects a representative node for each unit based on two conditions, called an agent. Then, the percentage of each unit covered by nodes can be accurately calculated and holes can be detected. Finally, the holes are recovered using the average of the key perceptual intersections as the initial value of the global optimal point of the particle swarm optimization algorithm. Simulation experiments show that the algorithm proposed in this paper reduces network energy consumption by 6.68%, decreases the distance traveled by mobile nodes by 8.51%, and increases the percentage of network hole recovery by 2.16%, compared with other algorithms. Full article

Disruptive color on animals’ bodies can reduce the risk of being caught. This study explores the camouflaging effect of disruptive color when applied to military targets. Disruptive and non-disruptive color patterns were placed on the target surface to form simulation materials. Then, the simulation target was set in woodland-, grassland-, and desert-type background images. The detectability of the target in the background was obtained by collecting eye movement indicators after the observer observed the background targets. The influence of background type (local and global), camouflage pattern type, and target viewing angle on the disruptive-color camouflage pattern was investigated. This study aims to design eye movement observation experiments to statistically analyze the indicators of first discovery time, discovery frequency, and first-scan amplitude in the target area. The experimental results show that the first discovery time of mixed disruptive-color targets in a forest background was significantly higher than that of non-mixed disruptive-color targets (t = 2.54, p = 0.039), and the click frequency was reduced by 15% (p < 0.05), indicating that mixed disruptive color has better camouflage effectiveness in complex backgrounds. In addition, the camouflage effect of mixed disruptive colors on large-scale targets (viewing angle ≥ 30°) is significantly improved (F = 10.113, p = 0.01), providing theoretical support for close-range reconnaissance camouflage design. Full article

Introduction: Recent technological progress in optical imaging—such as adaptive optics, interferometry and tomography—has greatly improved the resolution of retinal imaging. The ability to capture sequential images over time is particularly valuable for continuous monitoring and assessment of retinal diseases. Methods: This cross-sectional study involved patients with type 2 diabetes mellitus and age-matched controls from the Diabetes and Ophthalmology Department of the Emergency Military Clinical Hospital “Dr. Constantin Papilian” Cluj-Napoca between October 2023 and October 2024. These patients were assessed for inclusion and exclusion criteria and then categorized into two groups: the diabetes group and control group. Each participant underwent a comprehensive ophthalmological examination and retinal evaluation using SS-OCT (Spectralis Heidelberg Engineering, Heidelberg, Germany). The parameters measured included the superficial and deep foveal avascular zones (FAZ) in only one eye for each patient, selected based on image quality. Additionally, each patient underwent quantitative analysis of serum C-reactive protein (CRP) levels. Results: A total of 33 patients (33 eyes) featured, 13 men and 20 women. The DM group showed statistically significant higher results for CRP value compared to healthy subjects (p < 0.001). Also, both superficial and deep FAZ areas were statistically significantly higher for diabetes patients compared to the healthy controls (p < 0.05). The correlation analysis revealed that there was no significant correlation between CRP and either superficial FAZ (p = 0.809) or deep FAZ (p = 0.659). However, a significant positive moderate correlation was found between superficial FAZ and deep FAZ (r = 0.577, p = 0.015). Conclusions: Our findings showed a significantly enlarged FAZ in diabetic patients compared to healthy individuals, highlighting its potential as an early indicator of microvascular alterations in diabetes. While CRP levels were notably elevated in the diabetic group, no significant association was found between CRP and FAZ measurements, suggesting that FAZ changes may occur independently of systemic inflammatory status. Full article

The design and investigation of electrochromic devices have advanced significantly, including distinct applications such as self-charged smart windows, aerospace interactive windows, low power flexible and ecofriendly displays, automatic dimming rearview, wearable smart textiles, military and civilian camouflage systems, electrochromic sensors, among others. Although significant progress has been made in related fields, achieving the full potential of electrochromic devices to meet the standards of maturity and practical applications remains a persistent challenge. Electrochromic devices are typically multilayered structures that can be designed as either rigid or flexible systems, depending on the type of substrate employed. Conventional electrochromic devices comprise layered structures that include transparent electrodes, electrochromic materials, ionic conductors, and ion storage materials. On the other hand, multifunctional systems integrate bifunctional materials or distinct functional layers to simultaneously achieve optical modulation and additional capabilities such as energy storage. The development of advanced materials, comprehensive electrochemical kinetic analysis, the optimization and advancement of process techniques and deposition methods, and innovative device designs are active areas of extensive global research. This review focuses on the recent advances in multifunctional electrochromic materials and devices with particular emphasis on the integration of electrochromic technology with other functional technologies. It further identifies current challenges, proposes potential solutions, and outlines future research directions focused on advancing this technology in both niche and scalable applications. Full article

Seoul systematically removed all graveyards that once lay within the city and its surrounding areas, a phenomenon notably distinct from urban development patterns in other parts of the world. After the Korean War, refugees and migrants poured into the devastated capital. In this postwar environment, cemeteries—traditionally sites of mourning and death—transformed into spaces of survival for displaced populations. With the military demarcation line preventing their return home, refugees began to envision their lost hometowns as “absent places”: unattainable utopias, idealized lands where all beauty resides—the very origin and endpoint of life. In contrast, Seoul, where they were forced to settle, became a “dystopia,” stripped of sanctity. Over time, however, the next generation reinterpreted this dystopia, gradually transforming it into a heterotopia. As Seoul’s urban landscape expanded, this heterotopia evolved into a Christian paradise. The second generation, having never experienced the trauma of displacement, found the newly constructed city comfortable and secure. Reinforced concrete buildings and asphalt roads became symbolic of paradise. The development of Gangnam—famously captured in Psy’s global hit “Gangnam Style”—represents a belated cultural revolution among younger generations in modern South Korea and exemplifies the transformation into a concrete paradise. Full article

Background and Objectives: Military capability may be reduced in hot environments with individuals at risk of exertional heat stroke (EHS). Heat tolerance testing (HTT) can be used to indicate readiness to return to duty following EHS. HTT traditionally relies on rectal core temperature (T_re) assessment via a rectal probe. This study investigated the use of gastrointestinal core temperature (T_gi) as an alternative to T_re during HTT. A secondary aim was to compare physiological factors between heat-tolerant and heat-intolerant trials. Materials and Methods: Australian Defence Force personnel undergoing HTT following known or suspected heat stroke volunteered (n = 23 cases participating in 26 trials) along with 14 controls with no known heat illness history. Confusion matrices enabled comparison of HTT outcome based on T_gi and T_re. The validity of T_gi compared to T_re during HTT was assessed using correlation and bias. Comparisons between heat-tolerant and intolerant trials were performed using non-parametric tests. Results: Although T_gi correlated closely with T_re (Spearman’s rank correlation $\rho$ = 0.893; median bias 0.2 °C) there was no consistent pattern in the differences between measures. Importantly, the two measures only agreed on heat tolerance outcome in 80% of trials with T_gi failing to detect heat intolerance identified by T_re in 6 of 8 trials. If T_gi was relied upon for diagnostic outcome, return to duty may occur before full recovery. None of the assessed covariates were related to the difference between T_re and T_gi. In addition, resting heart rate and systolic blood pressure were significantly lower and body surface area to mass ratio significantly higher in heat-tolerant compared to intolerant trials. Conclusions: It is not recommended to rely on T_gi instead of T_re during HTT. Resting heart rate and systolic blood pressure findings point to the importance of aerobic exercise in conveying heat tolerance along with body composition. Full article

Synthetic aperture radar (SAR) is now recognized as a critical source of observational data in domains such as military reconnaissance, maritime monitoring, and disaster response, owing to its ability to deliver fine spatial resolution and broad-area imaging irrespective of weather or daylight conditions [...] Full article

In many areas of operation, application-specific logic implemented in FPGAs (Field Programmable Gate Arrays) is critical. In these situations, various mitigation methods are used to reduce or completely eliminate malfunctions in the circuit resulting from undesired physical phenomena (e.g., ionizing radiation). Such phenomena may occur, among others, in medicine, the military, nuclear power, and space systems. One of the most popular methods is the use of triple modular redundancy (TMR). Here, the FPGA provides a good basis for building TMR-based safety-critical systems due to its concurrent processing. This paper presents an overview of the implementation of logic structures using TMR. In this paper, the authors focus on different concepts for the implementation of FSMs. The different concepts differ in the way TMR voters are attached and the extent of redundancy of the individual FSM components. The article compares the efficiency of the different solutions. In order to evaluate this efficiency, it is crucial to determine the logic utilization or the power consumption of a given implementation. In the experimental part of the article, the authors show the results of the synthesis of FSM benchmarks, for different mitigation models. The synthesis was carried out for both commercial and academic tools. Full article

The increasing frequency and intensity of wildfires in hard-to-reach and hazardous areas represents a significant challenge for traditional firefighting methods. Wildfires pose a growing threat to the environment, property, and human lives. In many cases, conventional suppression techniques prove ineffective, highlighting the need for innovative and efficient solutions. Recent fires in the Bohemian Switzerland National Park in the Czech Republic; the Los Angeles area in California, USA; and the southeastern region of South Korea have underscored the necessity for alternative wildfire mitigation strategies. This article explores the potential of employing military technologies, such as artillery systems and specialized munitions, in wildfire suppression. The analysis includes a review of previous experiments, the research into non-standard methods, and an assessment of the risks and limitations associated with these approaches. Based on the research and simulations, it was found that one salvo (eight rounds) of fire-suppressant shells can cover up to 650 m² of terrain with suppressant. Finally, this article proposes a direction for further research aimed at integrating military and civilian technologies to enhance the effectiveness of wildfire response. This work contributes to the ongoing discussion on the integration of artillery capabilities into crisis management and provides a foundation for the future research in this field. Full article

The civil and military use of autonomously or remotely controlled unmanned aerial vehicles (UAVs) has become standard in many sectors. However, their role as supplementary vehicles for helicopter emergency medical services (HEMS) or search and rescue (SAR)—particularly when aiding individuals in hard-to-reach terrains—remains underexplored and in need of further innovation. The feasibility of using UAVs in such operations depends on multiple factors, including legislative, economic, and market conditions. However, the most critical considerations are external factors that impact UAV flight, such as meteorological conditions (wind speed and direction), the designated operational area, the proficiency of the pilot–operator, and the classification and certification of the UAV, particularly if it has been modified for such missions. Additionally, the feasibility of the remote or autonomous control of the UAV in mountainous environments plays a crucial role in determining their effectiveness. Establishing a specialized simulation environment to address these challenges is essential for assessing UAV performance in mountainous regions. This is particularly relevant in the Slovak Republic, a very rugged landscape, where the planned expansion of UAV-assisted rescue operations must be preceded by thorough testing, flight verification, and operational planning within protected landscape areas. Moreover, significant legislative changes will be required, which can only be implemented after the comprehensive testing of UAV operations in these specific mountain environments. Full article