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22 pages, 1515 KB  
Article
Living Rhythms: Investigating Networks and Relational Sensorial Island Rhythms Through Artistic Research
by Ann Burns
Arts 2026, 15(2), 31; https://doi.org/10.3390/arts15020031 - 3 Feb 2026
Abstract
Awaken, aware, arise, perform, pause, and repeat. The actions of the everyday. Without it, we fall into dysregulation. This paper seeks to examine creative research developed as an experiment during COVID-19, an audiovisualscape in virtual reality (VR). Rhythmanalysis+ is a social, ecological, and [...] Read more.
Awaken, aware, arise, perform, pause, and repeat. The actions of the everyday. Without it, we fall into dysregulation. This paper seeks to examine creative research developed as an experiment during COVID-19, an audiovisualscape in virtual reality (VR). Rhythmanalysis+ is a social, ecological, and sensorial enquiry into materiality, grounded in archipelagic thinking, through the lens of Rhythmanalysis, a form of analysis focusing on the everyday, through the lens of cyclical and linear rhythms. (Lefebvre). The research will also draw on Deleuze and Guattari’s rhizome theory, a botanical and philosophical investigation into networks. Networks form the backbone of the research. Lars Bang Larsen also argues that networks offer a distinctive view on how factual, speculative, historical, and non-human elements envelop and intertwine. Glissant’s archipelagic thought promotes transformation, multiplicity, and a sense of unpredictability. For this work, four inhabitants from Sherkin, a small island off the southwest coast of Ireland with a population of 100, became the research focus. Across four weeks, islanders gathered data from their daily sensory rhythms. Flight patterns of birds and bats were recorded, daily tasks noted, pathways cycled. Relational impacts of animal-odour on farming, weather, and tides were processed remotely, and an immersive cartographic score was created as a direct response in a three-dimensional virtual space. Rhythmanalysis+ analyses our newly altered perceptions of time and space as a material within a virtual world. VR, created as a gaming platform, is being pushed by art itself, forcing us to relook at the natural world, which is not static, but relational. Fluid but equally extractive, it is important to look at technology’s impact on all that is human and how it is perceived within the body as it is reframed digitally. Full article
(This article belongs to the Special Issue The Impact of the Visual Arts on Technology)
32 pages, 11526 KB  
Review
Transferability and Robustness in Proximal and UAV Crop Imaging
by Jayme Garcia Arnal Barbedo
Agronomy 2026, 16(3), 364; https://doi.org/10.3390/agronomy16030364 - 2 Feb 2026
Viewed by 35
Abstract
AI-driven imaging is becoming central to crop monitoring, with proximal and unmanned aerial vehicle (UAV) platforms now routinely used for disease and stress detection, yield estimation, canopy structure, and fruit counting. Yet, as these models move from plots to farms, the main bottleneck [...] Read more.
AI-driven imaging is becoming central to crop monitoring, with proximal and unmanned aerial vehicle (UAV) platforms now routinely used for disease and stress detection, yield estimation, canopy structure, and fruit counting. Yet, as these models move from plots to farms, the main bottleneck is no longer raw accuracy but robustness under distribution shift. Systems trained in one field, season, cultivar, or sensor often fail when the scene, sensor, protocol, or timing changes in realistic ways. This review synthesizes recent advances on robustness and transferability in proximal and UAV imaging, drawing on a corpus of 42 core studies across field crops, orchards, greenhouse environments, and multi-platform phenotyping. Shift types are organized into four axes, namely scene, sensor, protocol, and time. The article also maps the empirical evidence on when RGB imaging alone is sufficient and when multispectral, hyperspectral, or thermal modalities can potentially improve robustness. This serves as a basis to synthesize acquisition and evaluation practices that often matter more than architectural tweaks, which include phenology-aware flight planning, radiometric standardization, metadata logging, and leave-one-field/season-out splits. Adaptation options are consolidated into a practical symptom/remedy roadmap, ranging from lightweight normalization and small target-set fine-tuning to feature alignment, unsupervised domain adaptation, style translation, and test-time updates. Finally, a benchmark and dataset agenda are outlined with emphasis on object-oriented splits, cross-sensor and cross-scale collections, and longitudinal datasets where the same fields are followed across seasons under different management regimes. The goal is to outline practices and evaluation protocols that support progress toward deployable and auditable systems, noting that such claims require standardized out-of-distribution testing and transparent reporting as emphasized in the benchmark specification and experiment suite proposed here. Full article
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16 pages, 7688 KB  
Article
Vision-Only Localization of Drones with Optimal Window Velocity Fusion
by Seokwon Yeom
Electronics 2026, 15(3), 637; https://doi.org/10.3390/electronics15030637 - 2 Feb 2026
Viewed by 44
Abstract
Drone localization is essential for various purposes such as navigation, autonomous flight, and object tracking. However, this task is challenging when satellite signals are unavailable. This paper addresses database-free vision-only localization of flying drones using optimal window template matching and velocity fusion. Assuming [...] Read more.
Drone localization is essential for various purposes such as navigation, autonomous flight, and object tracking. However, this task is challenging when satellite signals are unavailable. This paper addresses database-free vision-only localization of flying drones using optimal window template matching and velocity fusion. Assuming the ground is flat, multiple optimal windows are derived from a piecewise linear segment (regression) model of the image-to-real world conversion function. The optimal window is used as a fixed region template to estimate the instantaneous velocity of the drone. The multiple velocities obtained from multiple optimal windows are integrated by a hybrid fusion rule: a weighted average for lateral (sideways) velocities, and a winner-take-all decision for longitudinal velocities. In the experiments, a drone performed a total of six medium-range (800 m to 2 km round trip) and high-speed (up to 14 m/s) maneuvering flights in rural and urban areas. The flight maneuvers include forward-backward, zigzags, and banked turns. Performance was evaluated by root mean squared error (RMSE) and drift error of the GNSS-derived ground-truth trajectories and rigid-body rotated vision-only trajectories. Four fusion rules (simple average, weighted average, winner-take-all, hybrid fusion) were evaluated, and the hybrid fusion rule performed the best. The proposed video stream-based method has been shown to achieve flight errors ranging from a few meters to tens of meters, which corresponds to a few percent of the flight length. Full article
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22 pages, 122921 KB  
Article
GD-DAMNet: Real-Time UAV-Based Overhead Power-Line Presence Recognition Using a Lightweight Knowledge Distillation with Mamba-GhostNet v2 and Dual-Attention
by Shuyu Sun, Yingnan Xiao, Gaoping Li, Yuyan Wang, Ying Tan, Jundong Xie and Yifan Liu
Entropy 2026, 28(2), 166; https://doi.org/10.3390/e28020166 - 31 Jan 2026
Viewed by 83
Abstract
Power-line presence recognition technology for unmanned aerial vehicles (UAVs) is one of the key research directions in the field of UAV remote sensing. With the rapid development of UAV technology, the application of UAVs in various fields has become increasingly widespread. However, when [...] Read more.
Power-line presence recognition technology for unmanned aerial vehicles (UAVs) is one of the key research directions in the field of UAV remote sensing. With the rapid development of UAV technology, the application of UAVs in various fields has become increasingly widespread. However, when flying in urban and rural areas, UAVs often face the danger of obstacles such as power lines, posing challenges to flight safety and stability. To address this issue, this study proposes a novel method for presence recognition in UAVs for power lines using an improved GhostNet v2 knowledge distillation dual-attention mechanism convolutional neural network. The construction of a real-time UAV power-line presence recognition system involves three aspects: dataset acquisition, a novel network model, and real-time presence recognition. First, by cleaning, enhancing, and segmenting the power-line data collected by UAVs, a UAV power-line presence recognition image dataset is obtained. Second, through comparative experiments with multi-attention modules, the dual-attention mechanism is selected to construct the CNN, and the UAV real-time power-line presence recognition training is conducted using the SGD optimiser and Hard-Swish activation function. Finally, knowledge distillation is employed to transfer the knowledge from the dual-attention mechanism-based CNN to the nonlinear function and Mamba-enhanced GhostNet v2 network, thereby reducing the model’s parameter count and achieving real-time recognition performance suitable for mobile device deployment. Experiments demonstrate that the UAV-based real-time power-line presence recognition method proposed in this paper achieves real-time recognition accuracy rates of over 91.4% across all regions, providing a technical foundation for advancing the development and progress of UAV-based real-time power-line presence recognition. Full article
(This article belongs to the Section Signal and Data Analysis)
28 pages, 12856 KB  
Article
Numerical Study on the Aerodynamic Performance of a UAV S-Shaped Inlet with Grilles
by Shu Yang, Mingshuang Shi, Dongpo Li, Zhenlong Wu, Huijun Tan, Jiahao Ren and Liming Yang
Aerospace 2026, 13(2), 129; https://doi.org/10.3390/aerospace13020129 - 29 Jan 2026
Viewed by 120
Abstract
This investigation designs grilles of two configurations inside an S-shaped inlet for UAVs. The present work numerically investigates the effects of the configurations, numbers, diameters, and lengths of the grilles on the inlet aerodynamic performance under different flight conditions, such as airflow Mach [...] Read more.
This investigation designs grilles of two configurations inside an S-shaped inlet for UAVs. The present work numerically investigates the effects of the configurations, numbers, diameters, and lengths of the grilles on the inlet aerodynamic performance under different flight conditions, such as airflow Mach number, angle of attack, and sideslip angle. The influences of the baseline configuration, Configuration 1, and Configuration 2 on the aerodynamic performance of the inlet are systematically compared. The numerical results show that after installing the grilles, the total pressure recovery decreases by an average of 5.42% for Configuration 1 and 3.46% for Configuration 2. In terms of the absolute circumferential total pressure distortion, which decreases by 1.26% for Configuration 1 and 2.34% for Configuration 2, the swirl distortion index of Configuration 2 approaches zero. It is found that a large sideslip angle significantly degrades the inlet performance, and Configuration 1 experiences the maximum decline of approximately 0.0124 in the total pressure recovery. Based on the optimized design of Configuration 1, the optimal parameters are determined as 5 grille rows, a grille diameter of 4 mm, and a grille length of 6 mm. This configuration achieves an optimal balance between flow regulation and resistance suppression, with a maximum total pressure recovery of 0.9884 and the absolute circumferential total pressure distortion controlled below 0.015. This study clarifies the optimization direction of key parameters for grilles and provides a theoretical basis and technical reference for the design of UAV S-shaped inlet and grille integrations. Full article
(This article belongs to the Section Aeronautics)
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14 pages, 6270 KB  
Article
First Clinical Experiences with the Ultra-Fast Time-of-Flight BIOGRAPH One Next-Generation Hybrid PET/MRI System
by Otto M. Henriksen, Kirsten Korsholm, Annika Loft, Johanna M. Hall, Annika R. Langkilde, Vibeke A. Larsen, Thomas S. Kristensen, Caroline Ewertsen, Frederikke E. Høi-Hansen, Patrick M. Lehmann, Karen Kettless, Flemming L. Andersen, Thomas L. Andersen and Ian Law
Diagnostics 2026, 16(3), 398; https://doi.org/10.3390/diagnostics16030398 - 27 Jan 2026
Viewed by 350
Abstract
Objective: We present the first clinical experience with the BIOGRAPH One next-generation PET/MRI system scanner, evaluating its performance for body and brain imaging in patients across multiple tracers. Methods: A total of 59 patients were scanned on the BIOGRAPH One PET/MRI following [...] Read more.
Objective: We present the first clinical experience with the BIOGRAPH One next-generation PET/MRI system scanner, evaluating its performance for body and brain imaging in patients across multiple tracers. Methods: A total of 59 patients were scanned on the BIOGRAPH One PET/MRI following standard clinical PET/CT (n = 52) or first-generation PET/MRI (Biograph mMR, n = 7). Scans comprised 30 total body (TB), whole body (WB), or regional scans with [18F]FDG, and 29 brain scans with either [18F]FDG (n = 5), [18F]FE-PE2I (n = 10), [18F]FET (n = 4), or [68Ga]Ga-DOTATOC (n = 10). The PET image quality was visually assessed using a 5-point Likert scale (1 = very good to 5 = very bad) and compared with clinical scans acquired on either a current-generation digital PET/CT or a first-generation PET/MRI system, including evaluation of diagnostic concordance. PET quantification and image noise was compared in brain and WB/TB [18F]FDG PET scans. Results: PET image quality was rated as good or very good in 93% of scans with a median [inter-quartile range] score of 1.5 [1.5;2]. In 99% of cases, image quality was judged equal to or better than the clinical reference scan (median score 3 [2.5;3]). Diagnostic concordance was observed in 99% of readings. Imaging metrics revealed the anticipated regional bias in brain imaging, while no significant bias was observed in body imaging. Image noise was comparable to that observed with digital PET/CT and demonstrated superiority over first-generation PET/MRI despite potential degradation related to isotope decay in BIOGRAPH One PET/MRI acquisitions scans performed at the end of the imaging workflow. Conclusions: Within the study limitations related to sequential imaging, the BIOGRAPH One PET/MRI scanner demonstrated improved PET sensitivity and workflow potential over its first-generation predecessor, which may allow for broader clinical and research applications. Full article
(This article belongs to the Section Medical Imaging and Theranostics)
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25 pages, 7286 KB  
Article
High-Altitude UAV-Based Detection of Rice Seedlings in Large-Area Paddy Fields
by Zhenhua Li, Xinfeng Yao, Songtao Ban, Dong Hu, Minglu Tian, Tao Yuan and Linyi Li
Agriculture 2026, 16(3), 307; https://doi.org/10.3390/agriculture16030307 - 26 Jan 2026
Viewed by 151
Abstract
Accurate quantification of field-grown rice seedlings is essential for evaluating yield potential and guiding precision field management. Unmanned aerial vehicle (UAV)-based remote sensing, with its high spatial resolution and broad coverage, provides a robust basis for accurate seedling detection and population density estimation. [...] Read more.
Accurate quantification of field-grown rice seedlings is essential for evaluating yield potential and guiding precision field management. Unmanned aerial vehicle (UAV)-based remote sensing, with its high spatial resolution and broad coverage, provides a robust basis for accurate seedling detection and population density estimation. However, in previous studies, UAVs were typically employed at relatively low altitudes, which provided high-resolution imagery and facilitated seedling recognition but limited efficiency. To enable large-area monitoring, higher flight altitudes are required, which reduces image resolution and adversely affects rice seedling recognition accuracy. In this study, UAVs were flown at a height of 30 m, and the resulting lower-resolution imagery, combined with the small size of seedlings, their dense spatial distribution, and the complex field background, necessitated algorithmic improvements for accurate detection. To address these challenges, we propose an enhanced You Only Look Once version 8 nano (YOLOv8n)-based detection model specifically designed to improve seedling recognition under high-altitude UAV imagery. The model incorporates an improved Bidirectional Feature Pyramid Network (BiFPN) for multi-scale feature fusion and small-object detection, a Global-to-Local Spatial Aggregation (GLSA) module for enriched spatial context modeling, and a Content-Guided Attention Fusion (CGAFusion) module to enhance discriminative feature learning. Experiments on high-altitude UAV imagery demonstrate that the proposed model achieves an mAP@0.5 of 94.7%, a precision of 91.0%, and a recall of 91.2%, representing a 2.3% improvement over the original YOLOv8n. These results highlight the model’s innovation in handling high-altitude UAV imagery for large-area rice seedling detection, demonstrating its effectiveness and practical potential under complex field conditions. Full article
(This article belongs to the Section Artificial Intelligence and Digital Agriculture)
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26 pages, 2167 KB  
Article
AI-Powered Service Robots for Smart Airport Operations: Real-World Implementation and Performance Analysis in Passenger Flow Management
by Eleni Giannopoulou, Panagiotis Demestichas, Panagiotis Katrakazas, Sophia Saliverou and Nikos Papagiannopoulos
Sensors 2026, 26(3), 806; https://doi.org/10.3390/s26030806 - 25 Jan 2026
Viewed by 325
Abstract
The proliferation of air travel demand necessitates innovative solutions to enhance passenger experience while optimizing airport operational efficiency. This paper presents the pilot-scale implementation and evaluation of an AI-powered service robot ecosystem integrated with thermal cameras and 5G wireless connectivity at Athens International [...] Read more.
The proliferation of air travel demand necessitates innovative solutions to enhance passenger experience while optimizing airport operational efficiency. This paper presents the pilot-scale implementation and evaluation of an AI-powered service robot ecosystem integrated with thermal cameras and 5G wireless connectivity at Athens International Airport. The system addresses critical challenges in passenger flow management through real-time crowd analytics, congestion detection, and personalized robotic assistance. Eight strategically deployed thermal cameras monitor passenger movements across check-in areas, security zones, and departure entrances while employing privacy-by-design principles through thermal imaging technology that reduces personally identifiable information capture. A humanoid service robot, equipped with Robot Operating System navigation capabilities and natural language processing interfaces, provides real-time passenger assistance including flight information, wayfinding guidance, and congestion avoidance recommendations. The wi.move platform serves as the central intelligence hub, processing video streams through advanced computer vision algorithms to generate actionable insights including passenger count statistics, flow rate analysis, queue length monitoring, and anomaly detection. Formal trial evaluation conducted on 10 April 2025, with extended operational monitoring from April to June 2025, demonstrated strong technical performance with application round-trip latency achieving 42.9 milliseconds, perfect service reliability and availability ratings of one hundred percent, and comprehensive passenger satisfaction scores exceeding 4.3/5 across all evaluated dimensions. Results indicate promising potential for scalable deployment across major international airports, with identified requirements for sixth-generation network capabilities to support enhanced multi-robot coordination and advanced predictive analytics functionalities in future implementations. Full article
(This article belongs to the Section Sensors and Robotics)
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25 pages, 4895 KB  
Article
Drone-Enabled Non-Invasive Ultrasound Method for Rodent Deterrence
by Marija Ratković, Vasilije Kovačević, Matija Marijan, Maksim Kostadinov, Tatjana Miljković and Miloš Bjelić
Drones 2026, 10(2), 84; https://doi.org/10.3390/drones10020084 - 25 Jan 2026
Viewed by 295
Abstract
Unmanned aerial vehicles open new possibilities for developing technologies that support more sustainable and efficient agriculture. This paper presents a non-invasive method for repelling rodents from crop fields using ultrasound. The proposed system is implemented as a spherical-cap ultrasound loudspeaker array consisting of [...] Read more.
Unmanned aerial vehicles open new possibilities for developing technologies that support more sustainable and efficient agriculture. This paper presents a non-invasive method for repelling rodents from crop fields using ultrasound. The proposed system is implemented as a spherical-cap ultrasound loudspeaker array consisting of eight transducers, mounted on a drone that overflies the field while emitting sound in the 20–70 kHz range. The hardware design includes both the loudspeaker array and a custom printed circuit board hosting power amplifiers and a signal generator tailored to drive multiple ultrasonic transducers. In parallel, a genetic algorithm is used to compute flight paths that maximize coverage and increase the probability of driving rodents away from the protected area. As part of the validation phase, artificial intelligence models for rodent detection using a thermal camera are developed to provide quantitative feedback on system performance. The complete prototype is evaluated through a series of experiments conducted both in controlled laboratory conditions and in the field. Field trials highlight which parts of the concept are already effective and identify open challenges that need to be addressed in future work to move from a research prototype toward a deployable product. Full article
(This article belongs to the Special Issue Advances of UAV in Precision Agriculture—2nd Edition)
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20 pages, 3207 KB  
Article
Reliability Case Study of COTS Storage on the Jilin-1 KF Satellite: On-Board Operations, Failure Analysis, and Closed-Loop Management
by Chunjuan Zhao, Jianan Pan, Hongwei Sun, Xiaoming Li, Kai Xu, Yang Zhao and Lei Zhang
Aerospace 2026, 13(2), 116; https://doi.org/10.3390/aerospace13020116 - 24 Jan 2026
Viewed by 206
Abstract
In recent years, the rapid development of commercial satellite projects, such as low-Earth orbit (LEO) communication and remote sensing constellations, has driven the satellite industry toward low-cost, rapid development, and large-scale deployment. Commercial off-the-shelf (COTS) components have been widely adopted across various commercial [...] Read more.
In recent years, the rapid development of commercial satellite projects, such as low-Earth orbit (LEO) communication and remote sensing constellations, has driven the satellite industry toward low-cost, rapid development, and large-scale deployment. Commercial off-the-shelf (COTS) components have been widely adopted across various commercial satellite platforms due to their advantages of low cost, high performance, and plug-and-play availability. However, the space environment is complex and hostile. COTS components were not originally designed for such conditions, and they often lack systematically flight-verified protective frameworks, making their reliability issues a core bottleneck limiting their extensive application in critical missions. This paper focuses on COTS solid-state drives (SSDs) onboard the Jilin-1 KF satellite and presents a full-lifecycle reliability practice covering component selection, system design, on-orbit operation, and failure feedback. The core contribution lies in proposing a full-lifecycle methodology that integrates proactive design—including multi-module redundancy architecture and targeted environmental stress screening—with on-orbit data monitoring and failure cause analysis. Through fault tree analysis, on-orbit data mining, and statistical analysis, it was found that SSD failures show a significant correlation with high-energy particle radiation in the South Atlantic Anomaly region. Building on this key spatial correlation, the on-orbit failure mode was successfully reproduced via proton irradiation experiments, confirming the mechanism of radiation-induced SSD damage and providing a basis for subsequent model development and management decisions. The study demonstrates that although individual COTS SSDs exhibit a certain failure rate, reasonable design, protection, and testing can enhance the on-orbit survivability of storage systems using COTS components. More broadly, by providing a validated closed-loop paradigm—encompassing design, flight verification and feedback, and iterative improvement—we enable the reliable use of COTS components in future cost-sensitive, high-performance satellite missions, adopting system-level solutions to balance cost and reliability without being confined to expensive radiation-hardened products. Full article
(This article belongs to the Section Astronautics & Space Science)
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29 pages, 19977 KB  
Article
Drone-Based Road Marking Condition Mapping: A Drone Imaging and Geospatial Pipeline for Asset Management
by Minh Dinh Bui, Jubin Lee, Kanghyeok Choi, HyunSoo Kim and Changjae Kim
Drones 2026, 10(2), 77; https://doi.org/10.3390/drones10020077 - 23 Jan 2026
Viewed by 210
Abstract
This study presents a drone-based method for assessing the condition of road markings from high-resolution imagery acquired by a UAV. A DJI Matrice 300 RTK (Real-Time Kinematic) equipped with a Zenmuse P1 camera (DJI, China) is flown over urban road corridors to capture [...] Read more.
This study presents a drone-based method for assessing the condition of road markings from high-resolution imagery acquired by a UAV. A DJI Matrice 300 RTK (Real-Time Kinematic) equipped with a Zenmuse P1 camera (DJI, China) is flown over urban road corridors to capture images with centimeter-level ground sampling distance. In contrast to common approaches that rely on vehicle-mounted or street-view cameras, using a UAV reduces survey time and deployment effort while still providing views that are suitable for marking. The flight altitude, overlap, and corridor pattern are chosen to limit occlusions from traffic and building shadows while preserving the resolution required for condition assessment. From these images, the method locates individual markings, assigns a class to each marking, and estimates its level of deterioration. Candidate markings are first detected with YOLOv9 on the UAV imagery. The detections are cropped and segmented, which refines marking boundaries and thin structures. The condition is then estimated at the pixel level by modeling gray-level statistics with kernel density estimation (KDE) and a two-component Gaussian mixture model (GMM) to separate intact and distressed material. Subsequently, we compute a per-instance damage ratio that summarizes the proportion of degraded pixels within each marking. All results are georeferenced to map coordinates using a 3D reference model, allowing visualization on base maps and integration into road asset inventories. Experiments on unseen urban areas report detection performance (precision, recall, mean average precision) and segmentation performance (intersection over union), and analyze the stability of the damage ratio and processing time. The findings indicate that the drone-based method can identify road markings, estimate their condition, and attach each record to geographic space in a way that is useful for inspection scheduling and maintenance planning. Full article
(This article belongs to the Special Issue Urban Traffic Monitoring and Analysis Using UAVs)
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24 pages, 4004 KB  
Article
Spherical Bezier Curve-Based 3D UAV Smooth Path Planning Utilizing an Efficient Improved Exponential-Trigonometric Optimization
by Yitao Cao, Kang Chen and Gang Hu
Biomimetics 2026, 11(2), 85; https://doi.org/10.3390/biomimetics11020085 - 23 Jan 2026
Viewed by 238
Abstract
Path planning, as a key technology in unmanned aerial vehicle (UAV) systems, affects the overall efficiency of task completion and is often limited by energy consumption, obstacles, and maneuverability in complex application environments. Traditional algorithms have insufficient performance in nonlinear, multimodal, and multiconstraints [...] Read more.
Path planning, as a key technology in unmanned aerial vehicle (UAV) systems, affects the overall efficiency of task completion and is often limited by energy consumption, obstacles, and maneuverability in complex application environments. Traditional algorithms have insufficient performance in nonlinear, multimodal, and multiconstraints problems. Based on this, this paper proposes an improved exponential-trigonometric optimization (ETO) to solve a 3D smooth path planning model based on a spherical Bezier curve. Firstly, a fixed arc length resampling strategy is proposed to address the issue of the insufficient adaptability of existing path smoothing methods to dynamic threats. Generate a uniformly distributed set of reference points along the Bezier curve and combine it with spherical projection to improve the safety and efficiency of the flight path. On this basis, establish a total cost function that includes four types of costs. Secondly, a new ETO variant called IETO is proposed by introducing the alpha evolution strategy, noise and physical attack strategy, and opposition-based cross teaching strategy into ETO. Then, the effectiveness of IETO for addressing various optimization problems is showcased through population diversity analysis, ablation analysis, and benchmark experiments. Finally, the results of the simulation experiment indicate that IETO stably provides shorter and smoother safe paths for UAVs in three elevation maps with different terrain features. Full article
(This article belongs to the Section Biological Optimisation and Management)
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18 pages, 10692 KB  
Article
Short-Time Homomorphic Deconvolution (STHD): A Novel 2D Feature for Robust Indoor Direction of Arrival Estimation
by Yeonseok Park and Jun-Hwa Kim
Sensors 2026, 26(2), 722; https://doi.org/10.3390/s26020722 - 21 Jan 2026
Viewed by 203
Abstract
Accurate indoor positioning and navigation remain significant challenges, with audio sensor-based sound source localization emerging as a promising sensing modality. Conventional methods, often reliant on multi-channel processing or time-delay estimation techniques such as Generalized Cross-Correlation, encounter difficulties regarding computational complexity, hardware synchronization, and [...] Read more.
Accurate indoor positioning and navigation remain significant challenges, with audio sensor-based sound source localization emerging as a promising sensing modality. Conventional methods, often reliant on multi-channel processing or time-delay estimation techniques such as Generalized Cross-Correlation, encounter difficulties regarding computational complexity, hardware synchronization, and reverberant environments where time difference in arrival cues are masked. While machine learning approaches have shown potential, their performance depends heavily on the discriminative power of input features. This paper proposes a novel feature extraction method named Short-Time Homomorphic Deconvolution, which transforms multi-channel audio signals into a 2D Time × Time-of-Flight representation. Unlike prior 1D methods, this feature effectively captures the temporal evolution and stability of time-of-flight differences between microphone pairs, offering a rich and robust input for deep learning models. We validate this feature using a lightweight Convolutional Neural Network integrated with a dual-stage channel attention mechanism, designed to prioritize reliable spatial cues. The system was trained on a large-scale dataset generated via simulations and rigorously tested using real-world data acquired in an ISO-certified anechoic chamber. Experimental results demonstrate that the proposed model achieves precise Direction of Arrival estimation with a Mean Absolute Error of 1.99 degrees in real-world scenarios. Notably, the system exhibits remarkable consistency between simulation and physical experiments, proving its effectiveness for robust indoor navigation and positioning systems. Full article
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38 pages, 6647 KB  
Article
ST-DCL: A Spatio-Temporally Decoupled Cooperative Localization Method for Dynamic Drone Swarms
by Hao Wu, Zhangsong Shi, Zhonghong Wu, Huihui Xu and Zhiyong Tu
Drones 2026, 10(1), 69; https://doi.org/10.3390/drones10010069 - 20 Jan 2026
Viewed by 181
Abstract
In GPS-denied environments, the spatio-temporal coupling of errors caused by dynamic network topologies poses a fundamental challenge to cooperative localization, presenting existing methods with a dilemma: approaches pursuing global optimization lack dynamic adaptability, while those focusing on local adaptation struggle to guarantee global [...] Read more.
In GPS-denied environments, the spatio-temporal coupling of errors caused by dynamic network topologies poses a fundamental challenge to cooperative localization, presenting existing methods with a dilemma: approaches pursuing global optimization lack dynamic adaptability, while those focusing on local adaptation struggle to guarantee global convergence. To address this challenge, this paper proposes ST-DCL, a cooperative localization framework based on a novel principle of closed-loop spatio-temporal decoupling. The core of ST-DCL comprises two modules: a Dynamic Weighted Multidimensional Scaling (DW-MDS) optimizer, responsible for providing a globally consistent coarse estimate with provable convergence, and a specially designed Spatio-Temporal Graph Neural Network (ST-GNN) corrector, tasked with compensating for local nonlinear errors. The DW-MDS effectively suppresses interference from historical errors via an adaptive sliding window and confidence weights derived from our error propagation model. The key innovation of the ST-GNN lies in its two newly designed components: a Dynamic Topological Attention Module for actively modulating neighbor aggregation to inhibit spatial error diffusion, and a Dilated Causal Convolution Module for modeling long-term temporal dependencies to curb error accumulation. These two modules form a closed loop via a confidence feedback mechanism, working in synergy to achieve continuous error suppression. Theoretical analysis indicates that the framework exhibits bounded-error convergence under dynamic topologies. In simulations involving 200 nodes, velocities up to 50 m/s, and 15% NLOS links, the ST-DCL achieves a normalized root mean square error (NRMSE) of 0.0068, representing a 21% performance improvement over state-of-the-art methods. The practical efficacy and real-time capability are further validated through real-world flight experiments with a 10-UAV swarm in complex, GPS-denied scenarios. Full article
(This article belongs to the Section Drone Communications)
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20 pages, 3982 KB  
Article
AI-Driven Decimeter-Level Indoor Localization Using Single-Link Wi-Fi: Adaptive Clustering and Probabilistic Multipath Mitigation
by Li-Ping Tian, Chih-Min Yu, Li-Chun Wang and Zhizhang (David) Chen
Sensors 2026, 26(2), 642; https://doi.org/10.3390/s26020642 - 18 Jan 2026
Viewed by 177
Abstract
This paper presents an Artificial Intelligence (AI)-driven framework for high-precision indoor localization using single-link Wi-Fi channel state information (CSI), targeting real-time deployment in complex multipath environments. To overcome challenges such as signal distortion and environmental dynamics, the proposed system integrates adaptive and unsupervised [...] Read more.
This paper presents an Artificial Intelligence (AI)-driven framework for high-precision indoor localization using single-link Wi-Fi channel state information (CSI), targeting real-time deployment in complex multipath environments. To overcome challenges such as signal distortion and environmental dynamics, the proposed system integrates adaptive and unsupervised intelligence modules into the localization pipeline. A refined two-stage time-of-flight (TOF) estimation method is introduced, combining a minimum-norm algorithm with a probability-weighted refinement mechanism that improves ranging accuracy under non-line-of-sight (NLOS) conditions. Simultaneously, an adaptive parameter-tuned DBSCAN algorithm is applied to angle-of-arrival (AOA) sequences, enabling unsupervised spatio-temporal clustering for stable direction estimation without requiring prior labels or environmental calibration. These AI-enabled components allow the system to dynamically suppress multipath interference, eliminate positioning ambiguity, and maintain robustness across diverse indoor layouts. Comprehensive experiments conducted on the Widar2.0 dataset demonstrate that the proposed method achieves decimeter-level accuracy with an average localization error of 0.63 m, outperforming existing methods such as “Widar2.0” and “Dynamic-MUSIC” in both accuracy and efficiency. This intelligent and lightweight architecture is fully compatible with commodity Wi-Fi hardware and offers significant potential for real-time human tracking, smart building navigation, and other location-aware AI applications. Full article
(This article belongs to the Special Issue Sensors for Indoor Positioning)
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