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This paper presents the design, fabrication, and experimental validation of a compact four-port metasurface for tri-band X-band multiple-input multiple-output (MIMO) applications operating at 8.75 GHz, 9.75 GHz, and 10.5 GHz. The proposed structure employs a scalable unit-cell configuration to enhance radiation performance while maintaining a compact footprint. A four-port feeding mechanism is integrated to support MIMO operation with improved channel diversity and reduced mutual coupling. The metasurface is realized using a

32 \times 32

unit-cell array, where increasing the number of unit cells significantly improves gain due to enhanced aperture efficiency. The fabricated prototype is experimentally characterized, and the measured S-parameters demonstrate good impedance matching at the three operating frequencies, with acceptable agreement between simulation and measurement results. In addition, reduced mutual coupling between ports confirms effective MIMO performance across the three bands. Radiation characteristics are evaluated through both 2D and 3D patterns. The radiation patterns were measured for a single port at frequencies where the reflection coefficient shows optimal performance, specifically at 8.75 GHz, 9.75 GHz, and 10.5 GHz. At these frequencies, the antenna exhibits well-defined main lobes with symmetrical radiation characteristics, indicating stable radiation behavior across the operating band. The realized gain exceeds 12 dBi at all three frequencies, with a peak gain of approximately 13 dB, along with satisfactory directivity and radiation efficiency. The results confirm that array scaling is an effective approach for gain enhancement without significantly increasing system complexity. In addition, the proposed MIMO metasurface achieves excellent diversity performance with ECC values below 0.04, DG values close to 10 dB, balanced MEG characteristics, and CCL values below 4 bits/s/Hz. The obtained results confirm that the proposed metasurface is a promising candidate for compact high-performance X-band MIMO systems for radar and advanced wireless communication applications. Full article

(This article belongs to the Special Issue Current Research Progress in Microwave Metamaterials and Metadevices)

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19 pages, 312 KB

Open AccessArticle

Evaluation of Homomorphic Encryption Integration Strategies in Database Management Systems

by Henrique Jorge, Cristina Wanzeller and João Henriques

J. Cybersecur. Priv. 2026, 6(4), 110; https://doi.org/10.3390/jcp6040110 (registering DOI) - 27 Jun 2026

Abstract

Homomorphic Encryption (HE) has emerged as a promising approach for data processing without exposing sensitive information. Despite significant advances, the practical strategies for the integration of HE into widely used database management systems (DBMSs) remain limited due to performance constraints and architectural challenges. This paper explores HE integration strategies within DBMS, focusing on SQL Server, PostgreSQL, and M̃ariaDB. A methodology is proposed to assess the feasibility and performance of multiple HE schemes, including BFV, CKKS, BGV, TFHE, Paillier, and RSA (without padding). The evaluation considers different integration strategies, namely Python-based execution and native C++ extensions, across Windows and Debian environments. Experimental results obtained from four configurations demonstrate that the choice of HE scheme and integration strategy significantly impacts performance. Lattice-based schemes (BFV, CKKS, BGV) provide a balanced trade-off between functionality and efficiency, while TFHE incurs high computational costs due to its bit-level design. Native C++ integrations consistently outperform Python-based approaches, although the latter offer greater flexibility and ease of development. The findings highlight the feasibility of integrating HE into DBMS while emphasizing the importance of selecting appropriate schemes and integration mechanisms to meet application-specific requirements. The proposed evaluation framework provides preliminary insights into the relative behavior of different HE schemes and integration strategies under controlled experimental conditions, supporting future work on privacy-preserving DBMS design. Full article

(This article belongs to the Topic Recent Advances in Security, Privacy, and Trust, 2nd Edition)

23 pages, 16263 KB

Open AccessArticle

Spatial Behavior and Academic Performance Among Architecture Students: A Gender-Based Comparative Study

by Jamil Binabid

Buildings 2026, 16(13), 2576; https://doi.org/10.3390/buildings16132576 (registering DOI) - 27 Jun 2026

Abstract

Educational buildings are characterized by daily movement and continuous interaction between formal and informal learning spaces. Understanding how students navigate and occupy these environments and how these experiences affect their academic performance is essential for developing responsive, human-centered architectural strategies. This research investigates spatial behavior, movement patterns, and physical classroom environments, and their relationship with academic achievement among students in the College of Architecture and Digital Design building at Dar Al-Uloom University. A mixed-methods approach is adopted, combining student surveys, movement mapping, and grade analysis. Movement mapping was used to document circulation patterns, spatial occupancy, and pause behavior across different periods of the academic day. In addition, academic performance categories, together with observed movement and space-use patterns, are used to contextualize spatial engagement. Additionally, an investigative comparative analysis is conducted across two campuses (male and female). The findings indicate that higher-performing students generally exhibit greater movement diversity and spatial engagement, with observable differences in spatial behavior between male and female students. Full article

(This article belongs to the Section Building Energy, Physics, Environment, and Systems)

38 pages, 11358 KB

Open AccessArticle

CP5-Centered Parietal HD-tACS Is Associated with Improved Performance in a Smartphone-Based Shopping Task in Older Adults: A Behavioral and EEG Investigation

by Jiabao Hu, Yuhao Zhu, Mengdie Wang, Xiaorong Cheng, Xianfeng Ding and Zhao Fan

Brain Sci. 2026, 16(7), 678; https://doi.org/10.3390/brainsci16070678 (registering DOI) - 27 Jun 2026

Abstract

Background/Objectives: Older adults often experience difficulties in smartphone use, especially when digital tasks require goal maintenance, visual search, sequential action, and response verification. Working memory and parietal theta-band activity may support these cognitively demanding operations, but it remains unclear whether a single session of theta-frequency high-definition transcranial alternating current stimulation (HD-tACS), centered over CP5 as a parietal scalp location intended to approximate the left inferior parietal region, is associated with short-term changes in smartphone-task performance in aging. Methods: This study examined performance in a controlled smartphone-based shopping task and exploratory post-stimulation EEG correlates. In Experiment 1, 40 older adults were randomly assigned to active HD-tACS or sham stimulation. In Experiment 2, 28 older adults completed a reduced-trial EEG extension of the same task with electroencephalography (EEG) recording before and after stimulation. Results: Active stimulation improved smartphone-task performance, including faster completion under high cognitive load, higher target selection accuracy, and reduced difficulty–time slope. Working-memory performance on a two-back task was also improved, and individual differences in working-memory gains were associated with improvements in smartphone-task efficiency. Active HD-tACS most strongly improved target selection accuracy, and exploratory post-stimulation theta-power changes in posterior/parietal regions may have accompanied high-demand target-selection-accuracy improvement. These neural findings should be interpreted cautiously because the omnibus EEG effects were trend-level, EEG–behavior correlations were based on a small active-stimulation subgroup, data-quality sensitivity analyses indicated artifact-related instability in theta-power estimates, and the full exploratory EEG–behavior correlation matrix did not survive FDR correction. Conclusions: These findings provide short-term behavioral evidence that CP5-centered parietal HD-tACS may support performance in a cognitively demanding smartphone-based task and motivate further work at the intersection of neuromodulation, cognitive aging, and human–technology interaction. Full article

(This article belongs to the Special Issue Noninvasive Brain Stimulation for Cognitive Enhancement)

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25 pages, 2864 KB

Open AccessArticle

Research on Simulation Optimization of ART Charging Strategies in Automated Container Terminals

by Hongqi Huang, Rong Yang, Mengjie He, Nenad Zrnic, Ning Zhao and Xiangwei Liu

J. Mar. Sci. Eng. 2026, 14(13), 1183; https://doi.org/10.3390/jmse14131183 (registering DOI) - 27 Jun 2026

Abstract

In automated container terminals, Autonomous Rail-guided Transporters (ARTs) are responsible for horizontal transportation tasks between quay cranes and yard blocks during unloading operations. Their charging strategies directly affect operational continuity, charging resource utilization, and road traffic load. To improve the consistency between the simulation environment and the actual terminal layout, this study constructs a DXF-based directed traffic network based on the CAD/DXF layout of Tianjin Port Second Container Terminal. A coupled discrete-event simulation model integrating ART operations, charging behavior, and traffic dynamics is developed using SimPy. The study further compares several charging strategies, including threshold charging, conventional opportunity charging, safe opportunity charging, interval charging, and Distance-Aware Interval Charging (DAIC). The results indicate that the conventional opportunity charging strategy suffers from battery depletion failures under continuous unloading task flows due to the absence of mandatory low-battery protection. After introducing a safety threshold, the safe opportunity charging strategy effectively eliminates the risk of battery depletion. Considering comprehensive performance indicators, including operational success rate, task completion time, charging travel distance, charging frequency, minimum State of Charge (SOC), and road congestion level, the 40%/70% interval charging strategy demonstrates strong overall robustness, while the 40%/80% interval charging strategy shows advantages in completion time and charging resource utilization. Both strategies can therefore be regarded as key candidate charging schemes for ART operations in Tianjin Port Second Container Terminal. Full article

(This article belongs to the Special Issue Sustainable Maritime Transport, Ports, Supply Chain Intelligence, and Marine Environmental Engineering)

34 pages, 1477 KB

Open AccessArticle

Fractional Stochastic Modeling of Nonlinear Dynamical Systems: Application to an Electromechanical Process with Memory Effects

by Anwarud Din

Fractal Fract. 2026, 10(7), 440; https://doi.org/10.3390/fractalfract10070440 (registering DOI) - 27 Jun 2026

Abstract

In this study, a comprehensive stochastic and fractional-order modeling framework is developed to investigate the dynamic behavior of a shunt DC motor under random disturbances and memory effects. The motor dynamics are formulated as a system of stochastic differential equations incorporating Gaussian noise to represent uncertainties in the electrical and mechanical subsystems. The existence, stochastic ultimate boundedness, stationary distribution, and ergodic properties of the proposed model are established. To further enhance modeling capabilities, a modified Atangana–Baleanu–Caputo (mABC) fractional operator is introduced, enabling the incorporation of nonlocal memory effects inherent in electromechanical systems. The series solution is derived using the Laplace transform and the Adomian decomposition method to handle nonlinearities. Qualitative analysis of the solution is performed through fixed-point theory, while stability assessments utilize the T-Picard method. The results of the numerical simulation indicate that the stochastic model exhibits limited variability around the operating regimes, whereas the fractional-order representation is more effective at smoothing transient responses and limiting oscillatory behavior. The study proposes a realistic and adaptable method to analyze the dynamics of shunt DC motors with uncertainty and also presents useful information for the design and control of electromechanical systems. Full article

(This article belongs to the Section Life Science, Biophysics)

35 pages, 3092 KB

Open AccessArticle

Jerk-Constrained Feedrate Scheduling for Biaxial Contouring Systems: A Planning-to-Execution Simulation Study

by Yiqian Jia, Ruoqing Wu, Zeyun Shang, Jihang Wang, Yilin Yang and Sumin Guo

Appl. Sci. 2026, 16(13), 6432; https://doi.org/10.3390/app16136432 (registering DOI) - 27 Jun 2026

Abstract

Biaxial contouring systems are widely used in planar precision motion applications, where the assigned feedrate profile strongly affects motion smoothness, contour-following accuracy, and robustness during servo execution. However, many existing studies mainly focus on either controller-side contour-error regulation or planning-layer time optimality, while the influence of jerk-sensitive feedrate transitions on downstream contouring behavior is still insufficiently examined. To address this issue, this paper proposes a jerk-constrained and execution-aware feedrate scheduling framework for biaxial contouring systems. Starting from the admissible feedrate boundary determined by contour geometry and motion constraints, an acceleration-feasible baseline schedule is first generated through bidirectional reachability propagation. Then, jerk-oriented smoothness refinement and critical-region-preserving correction are introduced to suppress abrupt local transitions while maintaining dynamic admissibility and practical traversal efficiency. The refined path-domain schedule is further reconstructed into time-domain axis-level references for closed-loop contouring evaluation. A planning-to-execution simulation study is conducted on three representative contours, including a rounded triangular contour, an elliptical contour, and a butterfly-cross contour. The proposed method is compared with several baseline scheduling strategies under nominal, low-bandwidth, flexible-resonance, and parameter-mismatch conditions. The simulation results indicate that the proposed scheduler can reduce concentrated jerk responses and resonance-sensitive high-frequency excitation while achieving a more balanced tradeoff among traversal time, contouring accuracy, and robustness. The results also show that the benefit of the proposed method becomes more evident for geometrically complex contours and deteriorated servo conditions. The present study provides simulation-based evidence that execution-aware feedrate scheduling is an effective way to improve biaxial contouring performance without redesigning the low-level servo controller. Full article

18 pages, 1756 KB

Open AccessArticle

AI-Based Detection of Osteoporosis on Dental Radiographs: Influence of Region-of-Interest Selection on Classification Performance

by Michael Moncher, Vincent Traboulsi, Florian Kofler, Sarah Müller, Felix Steinbauer and Constantin von See

J. Imaging 2026, 12(7), 285; https://doi.org/10.3390/jimaging12070285 (registering DOI) - 27 Jun 2026

Abstract

Osteoporosis may alter mandibular bone structure and peri-implant remodeling, but it remains unclear whether such changes are detectable on dental radiographs using deep learning. This retrospective study evaluated whether osteoporosis can be discriminated in two mandibular regions of interest: peri-implant bone and the mental foramen region. Digital periapical radiographs acquired between November 2012 and October 2024 were analyzed in 51 women, including 25 patients with osteoporosis and 26 non-osteoporotic controls without a documented history or diagnosis of osteoporosis; the osteoporosis group was significantly older than the control group. Two binary classification experiments were performed using patient-level fivefold grouped cross-validation. The peri-implant experiment included 1682 cropped images and used an image-plus-metadata ResNet-18 model incorporating the time interval between implant placement and radiograph acquisition. The mental foramen experiment included 102 cropped images and used an image-only ResNet-18 model. Mean accuracy, F1 score, and area under the receiver operating characteristic curve were 0.613, 0.628, and 0.713 for the peri-implant region of interest (ROI) and 0.701, 0.713, and 0.744 for the mental foramen ROI, respectively. Both experiments showed substantial fold-to-fold variability. These findings suggest that ROI selection influences model behavior, but neither approach yielded sufficiently stable ROI-level classification performance under patient-level grouped validation to support individual patient-level screening claims. Nondiscriminatory AI results should therefore be interpreted as limited evidence under the present experimental conditions rather than as proof of radiographic equivalence. Full article

(This article belongs to the Section AI in Imaging)

28 pages, 5143 KB

Open AccessArticle

Hardware-in-the-Loop Simulation Platform for Hands-On Training in Grid-Connected Photovoltaic Systems

by Tania Castellanos Parada, Mauricio Bautista Porras, Juan M. Rey, María A. Mantilla Villalobos, Fausto Osorio Silva, Johann F. Petit Suárez and Rolando A. Rincón Saravia

Electricity 2026, 7(3), 62; https://doi.org/10.3390/electricity7030062 (registering DOI) - 27 Jun 2026

Abstract

The rapid expansion of photovoltaic (PV) generation has increased the need for educational and experimental platforms that allow students and researchers to study the dynamics, control strategies, and power conversion stages of grid-connected PV systems under realistic operating conditions. Although Hardware-in-the-Loop (HIL) simulation is widely used to validate power electronic converters and control algorithms, many existing platforms rely on specialized real-time simulators that limit their accessibility in academic environments. This paper presents the design and implementation of a cost-effective HIL simulation platform for grid-connected PV systems intended for research and training applications. The proposed system integrates real hardware under test within a real-time environment that emulates PV array behavior and grid conditions, combining Controller Hardware-in-the-Loop (CHIL) and Power Hardware-in-the-Loop (PHIL) techniques. A Texas Instruments C2000 microcontroller is used as the real-time digital simulator, providing an accessible alternative to conventional real-time simulation platforms. The platform architecture, the real-time PV emulator, and the experimental implementation are described and validated through simulation and experimental results. Finally, guided laboratory practices are presented to support hands-on training in PV systems and power electronics. Full article

18 pages, 4343 KB

Open AccessArticle

Evaluation of Durability of Clay Stabilized with Philippine Quarry Dust-Based Geopolymer

by John Henry Andes Escoto and Erica Elice Saloma Uy

Appl. Sci. 2026, 16(13), 6430; https://doi.org/10.3390/app16136430 (registering DOI) - 27 Jun 2026

Abstract

High-plasticity clays (CH) are widely recognized in geotechnical engineering for their poor engineering behavior, including low shear strength, high compressibility, and swelling potential, yet their presence in infrastructure projects is often unavoidable. This study investigates a sustainable alternative to ordinary Portland cement (OPC) by evaluating the durability of soil–geopolymer mixtures (SGMs) incorporating quarry dust (QD), an industrial by-product from sand and gravel operations in the Philippines. Durability assessment was emphasized due to the country’s tropical climate, marked by alternating wet and dry seasons that may accelerate deterioration of stabilized soils. QD was activated using sodium silicate (SS) and sodium hydroxide (SH) and blended with CH to form SGMs. Index property tests were conducted to characterize raw materials and identify optimal mix proportions. After 28 days of curing, specimens were subjected to wetting–drying (WD) cycles consisting of 5 h of water submersion and 42 h of oven-drying at 70 °C. Mass loss and surface degradation were evaluated by brushing in accordance with ASTM procedures. The SGMs exhibited an average mass loss of 6.83% after 12 WD cycles, satisfying the Portland Cement Association (PCA) criterion of less than 7.00% for stabilized clays. These results demonstrate that QD-based geopolymers are a viable and sustainable stabilizer for CH soils in tropical environments. Full article

(This article belongs to the Special Issue Recent Advancements in Soil Mechanics and Geotechnical Engineering)

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14 pages, 3426 KB

Open AccessArticle

Rheology-Informed Working Thresholds for HME/FDM Processability in a PVA–Sorbitol–Paracetamol Model System

by Sofiya Ilieva, Dilyana Georgieva, Valentina Petkova and Milen Dimitrov

Pharmaceutics 2026, 18(7), 791; https://doi.org/10.3390/pharmaceutics18070791 (registering DOI) - 27 Jun 2026

Abstract

Background/Objectives: Oscillatory rheology is widely used in hot-melt extrusion (HME) and fused deposition modeling (FDM), but its translation into compact formulation-screening criteria remains limited. This study re-analyzed an existing PVA–sorbitol–paracetamol dataset to derive rheology-informed working thresholds for HME/FDM processability. Methods: Temperature-ramp oscillatory rheology was used to extract formulation-level descriptors: process-temperature complex viscosity (|η*|) at 185 and 200 °C, Processing Window Fraction (PWF) within the 0.8–10 kPa·s corridor, and crossover-related temperature information. These descriptors were interpreted against empirical extrusion at 200 °C and printing at 185 °C. Results: S1.25 and S1.5 showed rheological behavior compatible with successful extrusion, whereas S1.75 showed pronounced softening consistent with over-plasticization and process failure. Paracetamol further reduced complex viscosity while maintaining processability in P5–P15. The lowest successful process-temperature viscosity values, observed for P15, supported working thresholds of approximately 0.460 kPa·s at 200 °C and 0.899 kPa·s at 185 °C. PWF complemented thresholding by describing the practical temperature flexibility of each formulation. Conclusions: Process-temperature |η*|, PWF, and crossover-informed interpretation provided a compact, formulation-specific screening framework for this PVA-based HME/FDM model system. The proposed thresholds are operational derivation outputs and require prospective external confirmation. Full article

(This article belongs to the Special Issue 3D Printing Technologies in Pharmaceutical Formulation)

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38 pages, 5124 KB

Open AccessReview

Intrusion Detection Datasets for IIoT and ICS: A Taxonomic Review with a Decision-Aid Scoring Rubric

by Ayman Termanini, Hadj Bourdoucen, Dawood Al-Abri and Ahmed Al Maashri

Sensors 2026, 26(13), 4099; https://doi.org/10.3390/s26134099 (registering DOI) - 27 Jun 2026

Abstract

Dataset quality significantly affects the effectiveness of a machine learning (ML) model in an intrusion detection system (IDS) for cyber-physical industrial control systems (CPS/ICS) and Industrial Internet of Things (IIoT). Existing surveys compare datasets qualitatively or along limited dimensions, whereas this review introduces quantitative documentation and decision-aid scoring across 23 ICS/OT/IIoT datasets. These datasets are analyzed along seven measurable axes, with their attacks mapped to MITRE ATT&CK for ICS tactics. Quantitatively, 14 of the 23 datasets (60.9%) are built on physical testbeds, and 22 of the 23 map to MITRE ATT&CK for ICS, spanning 11 of the 12 tactics. We introduce a checklist for documentation completeness (0–7) and a decision-aid rubric (0–15) covering realism, attack diversity, class imbalance, documentation, and reproducibility. Protocol coverage across these datasets is skewed toward Modbus (13 of 23 datasets, 57%), while many other protocols (such as Profinet and OPC UA) are underrepresented relative to their industry deployment. The available datasets show structural gaps in capturing multi-stage adversary behavior. In practice, dataset selection should pair a realism-anchored dataset with a high-reproducibility one, and account for protocol diversity and APT representation. Full article

(This article belongs to the Special Issue Cyber Security and Privacy in Internet of Things (IoT))

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31 pages, 3510 KB

Open AccessArticle

Stability, Bifurcation Analysis and Chaos in a Discretized Fractional-Order Predator–Prey System with Nonlinear Functional Response

by Ibraheem M. Alsulami, Najat A. Alghamdi, M. T. Alharthi and Rizwan Ahmed

Mathematics 2026, 14(13), 2290; https://doi.org/10.3390/math14132290 (registering DOI) - 27 Jun 2026

Abstract

This study examines a discrete fractional-order predator–prey system incorporating a Holling type-III functional response. The Caputo fractional derivative is employed because it naturally incorporates memory and hereditary effects while preserving biologically meaningful initial conditions. The system is formulated from a biologically relevant continuous fractional-order framework through the application of the piecewise constant argument approach, enabling an analysis of how memory-dependent effects and discrete dynamics influence predator–prey interactions. The existence and local stability of fixed points are determined by using the Jacobian matrix and eigenvalue conditions. The bifurcation of the positive fixed point is analyzed by using the center manifold and normal form methods. Numerical simulations, including bifurcation diagrams, phase portraits, and maximum Lyapunov exponent plots, confirm our analytical results and reveal periodic, quasiperiodic, and chaotic behavior. The findings of this study reveal that the combined influence of memory-dependent dynamics, nonlinear predator–prey interactions, and discrete-time effects can generate rich and complicated behaviors in fractional-order predator-prey systems. Full article

(This article belongs to the Special Issue On Stability, Bifurcation, and Chaos in Dynamical Systems: Theory and Applications)

14 pages, 14696 KB

Open AccessArticle

Ti₂O-Based Saturable Absorbers: From Material Synthesis to Broadband Mode-Locked Fiber Laser Applications

by Guokai Dai, Yuanxiao Qu, Jinjuan Cheng, Chengcheng He, Wei Xu, Luo Yan and Jia Guo

Nanomaterials 2026, 16(13), 798; https://doi.org/10.3390/nano16130798 (registering DOI) - 27 Jun 2026

Abstract

Saturable absorbers (SAs) are critical for passive mode-locking in ultrafast fiber lasers. Although many materials have been studied as SAs, new candidates with broadband and stable performance are still needed. In this work, we report the synthesis and fabrication of Ti₂O-based SAs and present the first systematic investigation of their performance in broadband ultrafast fiber lasers. Specifically, phase-pure Ti₂O crystals were synthesized via solid-state sintering. High-performance Ti₂O SAs were then fabricated through a photodeposition method. The balanced synchronous twin-detector measurement method demonstrated that Ti₂O exhibited obvious and stable saturable absorption behavior. To validate their broadband mode-locking capability, the as-prepared Ti₂O SAs were integrated into the Yb-doped and Er-doped fiber lasers, respectively. Experimental results show that both laser systems deliver stable pulsed output, with pulse durations of 441.7 ps at 1 μm and 522.5 fs at 1.5 μm. This work pioneers the application of Ti₂O in ultrafast photonics, and provides an important reference and novel research insights for the design and development of advanced broadband optical devices and systems. Full article

(This article belongs to the Special Issue Nonlinear Optical Performance of Nanomaterials)

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36 pages, 6924 KB

Open AccessArticle

A New Fixed-Cost Approximation for Ellipse–Ellipse Intersection: A Case Study in Tree-Crown Delineation Post-Processing

by Mohamad Shatnawi, Enas Elshebli, Erdős Ferenc and Földesi Péter

Remote Sens. 2026, 18(13), 2096; https://doi.org/10.3390/rs18132096 (registering DOI) - 27 Jun 2026

Abstract

The intersection area between two arbitrarily rotated ellipses is a recurring geometric primitive in imaging, computer vision, and robotics. In the general case, its evaluation is often associated with intersection-point recovery, topology-dependent case handling, adaptive refinement, or dense boundary approximation. This study presents a fixed-cost computational framework for ellipse–ellipse intersection based on a rotated-frame slice formulation. A coordinate-frame rotation expresses one ellipse in axis-aligned form while representing the second as a general conic. This yields a hybrid formulation that reduces the intersection area to a one-dimensional overlap integral of vertical slice height over the admissible horizontal interval. The integral is evaluated using fixed-order quadrature, with optional sine mapping to improve conditioning near grazing configurations. Numerical evaluation on 100,000 synthetic ellipse pairs shows that the proposed formulation reaches a low-error regime earlier than polygonal approximation while remaining substantially faster across the tested range. The formulation is further examined through a tree-crown delineation case study on the BAMFORESTS dataset, a benchmark forest dataset of very-high-resolution UAV imagery. In this case study, ellipse proxies derived from axis-aligned and oriented bounding box detections are used for overlap computation during non-maximum suppression (NMS). Using ellipse-proxy overlap during NMS preserves nearly the same peak F1 score of 0.785 while modestly shifting NMS behavior toward lower thresholds and producing slightly broader near-peak intervals. Full article

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