Search Results (86)

Insufficient three-dimensional (3D) geolocation accuracy of interferometric synthetic aperture radar (InSAR) scatterers on dikes often hampers the distinction between the dike crest and slopes. This limitation hinders effective monitoring and interpretation of deformation associated with different dike structures using the multi-temporal InSAR (MT-InSAR) technique. To address this, we propose a geolocation improvement method by integrating light detection and ranging (LiDAR) point cloud. We first construct and transform a 3D error ellipsoid of each InSAR scatterer by quantitatively estimating its geolocation uncertainty. Next, we design and employ a rotation matrix and projection model to extract LiDAR points located within each error ellipsoid. Then we use the mean position and height of the extracted LiDAR counterparts to improve the geolocation accuracy of the InSAR scatterers. The Houtribdijk, as our test site, is a 26.5 km long dike in the Netherlands, where we used both ascending and descending Sentinel-1 tracks acquired from 2018 to 2022. Results show that the original geocoded InSAR scatterers exhibit positional and height discrepancies between the two datasets, and their height variations fail to reflect the actual topographic features of individual slopes. After improvement, the heights of the InSAR scatterers agree well with LiDAR measurements, with root mean square errors reduced by up to 97%. Coefficients of determination with the AHN4-derived digital surface model increase from 0.22 and 0.24 to 0.82 and 0.78 for ascending and descending tracks, respectively, and reach 0.96 along the Houtribdijk. The percentage of boundary scatterers located within the dike extent also increases from 42% and 20% to 85% and 84% for the ascending and descending tracks, respectively. This test demonstrates that our method effectively improves InSAR geolocation and provides the spatial and geometric basis for deformation analysis of different dike structures. Full article

To address unstable seed filling and susceptibility to seed damage in air-suction peanut seed-metering devices, a flexible cell-hole seed-metering device comprising a double-layer seed-metering disc, elastic rubber cell-hole inserts, and conical springs was developed. EDEM simulations, bench tests, and field tests were conducted to investigate the effects of cell-hole type, cell-hole height, and seed-metering disc speed. Seed velocity, force, and disturbance transmission characteristics were analyzed in the simulations, while seed-metering performance was evaluated using the miss-seeding, multiple-seeding, and seed-damage indices in the bench tests. The results showed that the single ellipsoid cell-hole type produced greater consistency between the directions of seed motion and cell-hole movement. A cell-hole height of 5 mm provided an effective balance between seed disturbance and damage reduction, while a seed-metering disc speed of 20 r/min improved seed-adsorption stability. In the field tests, the mean miss-seeding, multiple-seeding, and seed-damage indices were 3.75%, 4.54%, and 1.75%, respectively. These findings demonstrate that flexible cell holes can guide seeds to move with the cell holes and promote the stable transmission of localized disturbance throughout the seed mass, thereby providing an effective approach to improving seed-adsorption stability while limiting mechanical damage. Full article

Conventional vibrational spectroscopy provides chemically specific identification of microplastics but often requires extensive sample preparation and particle-by-particle analysis. This study numerically examines a terahertz split-ring resonator (SRR) metasurface as a transducer for local dielectric perturbations in water. A finite-element model was used to quantify the spatial response of the active gap. A 5 × 5 sensitivity map yielded frequency shifts of 0.37–0.97 GHz for equivalent local polystyrene perturbations, with maxima at the gap corners, consistent with simulated field localization. An equal-volume shape study compared a spherical inclusion (Δf = 4.34 GHz) with ellipsoids of identical volume and constant height; shifts of 4.25–4.56 GHz demonstrated dependence on in-plane orientation. At the highest-sensitivity cell, shifts of 1.12, 0.97, 0.69, 0.25, and 0.24 GHz were obtained for PE, PS, PET, and two synthetic high-permittivity references, respectively. For three four-corner configurations, the observed shifts agreed with reference-cell estimates within 1.4%. The results identify positional, dielectric, and geometric factors that should be controlled in future microfluidic preconcentration and hybrid-sensing experiments. Full article

Background: To evaluate anatomical and functional outcomes following pars plana vitrectomy (PPV) for traumatic macular hole (TMH), investigate optical coherence tomography (OCT)-based prognostic factors, and compare outcomes between flap-based and non-flap internal limiting membrane (ILM) techniques. Methods: This retrospective consecutive case series included 33 eyes of 33 patients undergoing PPV for TMH between January 2017 and June 2024 at a tertiary referral center. Preoperative spectral-domain OCT parameters, including minimum linear diameter (MLD), basal diameter (BD), hole height (HH), intraretinal cysts, subretinal fluid, epiretinal membrane, and ellipsoid zone disruption, were evaluated. Anatomical closure and postoperative best-corrected visual acuity (BCVA) outcomes were analyzed. Results: The mean patient age was 28.7 ± 15.0 years, and blunt trauma accounted for 87.9% of cases. Median trauma-to-surgery interval was 10 weeks (IQR: 4–24 weeks). Mean BCVA improved significantly from 1.34 ± 0.54 logMAR preoperatively to 0.95 ± 0.59 logMAR postoperatively (p = 0.004). Single-surgery anatomical closure was achieved in 28 of 33 eyes (84.8%). Larger MLD and BD were significantly associated with poorer final BCVA, whereas greater HH was associated with successful anatomical closure. Flap-assisted techniques achieved higher closure rates compared with conventional ILM peeling (95.8% vs. 55.6%, p = 0.013). Conclusions: PPV for TMH was associated with favorable anatomical and functional outcomes. Larger hole dimensions were associated with poorer visual prognosis, whereas greater HH was associated with anatomical closure. Flap-assisted ILM techniques may improve anatomical success in TMH surgery. Full article

Background/Objectives: Accurate estimation of augmentation volume is essential for successful maxillary sinus augmentation planning. Manual CBCT-derived volumetric calculations remain time-consuming and operator-dependent. Artificial intelligence (AI)-assisted volumetric estimation may provide a standardized and reproducible alternative. This study evaluated the agreement and reliability of an AI-assisted volumetric estimation tool compared with CBCT-derived manually calculated augmentation volumes for sinus augmentation planning. Methods: A retrospective comparative study was conducted on 60 CBCT scans obtained from patients undergoing implant treatment planning. Radiographic measurements included bone width (A), residual alveolar bone height (B), sinus lift height (C), sinus lift width (D), and sinus lift depth (E). Manual augmentation volume was calculated using a geometric ellipsoid approximation formula derived from standardized linear measurements. AI-assisted volumetric estimation was performed using the volumetric analysis tool integrated within Planmeca Romexis 6.3 software. Two calibrated periodontists repeated both manual and AI-assisted measurements twice with a two-week interval. Reliability was assessed using intraclass correlation coefficients (ICC), while agreement between methods was evaluated using ICC and Bland–Altman analysis. Results: The mean manually calculated planned augmentation volume per implant site was 0.47 ± 0.11 cm³, whereas the mean AI-assisted planned augmentation volume was 0.52 ± 0.10 cm³. AI-assisted measurements were significantly greater than manual measurements (p < 0.001). Manual measurements demonstrated moderate intra- and inter-examiner reliability (ICC = 0.722, 0.701, and 0.649), whereas AI-assisted measurements demonstrated excellent reliability (ICC = 0.917, 0.924, and 0.903). Agreement between AI-assisted and manual volumetric estimation was good (ICC = 0.847). Bland–Altman analysis demonstrated a mean bias of 0.061 cm³ with limits of agreement ranging from 0.028 to 0.094 cm³. No significant associations were observed between augmentation volume and age, sex, or number of missing teeth after normalization per implant site (p > 0.05). Conclusions: AI-assisted volumetric estimation demonstrated excellent reproducibility and good agreement with manually calculated augmentation volumes while producing slightly higher volume estimates. AI-assisted volumetric estimation may serve as a reliable adjunctive tool for sinus augmentation planning by improving standardization and reducing operator-dependent variability. Full article

Height systems form a mathematical interface between physical geodesy, engineering surveying, and digital cartography. Although satellite positioning efficiently provides ellipsoidal heights, practical infrastructure, mapping, hydrological, and monitoring tasks require gravity-related heights that are compatible with national vertical datums. This paper develops a denominator-based framework in which dynamic, orthometric, and normal heights are interpreted as metric realizations of a common geopotential number. Starting from the line-integral definition of geopotential, the principal height formulae are derived; first-order sensitivities to geoid undulation, height anomaly, and mean gravity are established; and uncertainty propagation is analyzed. A Romania-oriented computational experiment, explicitly defined as a representative model-behavior study rather than an official national adjustment, uses lowland, plateau, and mountain-influenced settings consistent with the Constanta and Black Sea 1975 normal-height context. The results show that modeled normal-orthometric separations remain below 3 mm in representative low-relief locations but increase to 17.1 mm in Suceava, 29.5 mm in Cluj-Napoca, and 85.6 mm in the mountain-influenced Brasov case. The dynamic-normal differences remain small at low elevations but become systematic where the normal-gravity denominator departs from the selected reference value. The Monte Carlo experiment indicates standard uncertainties of approximately 4.2–4.4 cm for normal heights when a 1.5 cm ellipsoidal-height uncertainty and a 4.0 cm quasi-geoid uncertainty are assumed. A single-point covariance example gives 31.7 mm for normal-height conversion and 36.9 mm for orthometric-height conversion under the stated correlation assumptions. The transformation-surface comparison further shows that a quadratic local model reduces leave-one-out cross-validation error from 16.73 mm to 9.95 mm relative to a planar model in the synthetic Romania-oriented scenario. The study concludes that the height-system label must be treated as part of the mathematical model and metadata, and it proposes a geopotential-centered computational pathway for survey adjustment, uncertainty control, and metadata-safe geospatial export. Full article

Background/Objectives: A macular hole represents a significant surgical condition in an increasingly aging population. Advances in surgical techniques, particularly pars plana vitrectomy with inverted internal limiting membrane (ILM) flap, have established high anatomical closure rates exceeding 90%. The prognostic factors influencing visual recovery remain incompletely understood, and it is unclear which patients can be expected to achieve optimal functional outcomes. Methods: This retrospective longitudinal study included 35 eyes of 32 patients followed for 3–12 months. Preoperative OCT parameters (minimum linear diameter, basal diameter, and hole height) and derived indices were correlated with functional outcomes, including best-corrected visual acuity (BCVA) and microperimetry, stratified as central macular sensitivity (CMS) and sensitivity at 4° and 20°. Postoperative ellipsoid zone (EZ) and external limiting membrane (ELM) integrity were also analyzed. Predictive performance was assessed using root mean square error (RMSE) and coefficient of determination (R²). A linear regression model based on BCVA served as baseline, while Extreme Gradient Boosting (XGBoost) models incorporating OCT features were developed. Feature importance was evaluated using Shapley Additive Explanations (SHAP). Results: Overall closure rate was 100%, including 91.4% Type 1 and 8.6% Type 2 closure. Models incorporating OCT parameters outperformed BCVA-based models (lower RMSE, and higher R²). Minimum linear diameter and hole height were the strongest predictors of postoperative outcomes. Microperimetry detected functional improvement beyond BCVA and correlated with EZ and ELM restoration. Conclusions: Preoperative macular hole morphology represents a key determinant of postoperative functional recovery. These structural parameters provide meaningful prognostic value beyond visual acuity alone, supporting the role of combined OCT and microperimetric assessment in predicting surgical outcomes. Full article

Accurately forecasting the weighted mean temperature (Tm) is critical for converting the zenith wet delay (ZWD) into global navigation satellite system (GNSS)-based precipitable water vapor (PWV) for real-time sensing and forecasting applications. The forecast Vienna Mapping Function 1 (VMF1-FC) is a global forecast product developed by TU Wien based on numerical weather prediction models and can provide grid-wise Tm one day ahead. In this study, we evaluate the accuracy of VMF1-FC-forecasted Tm using observations from 319 global radiosonde (RS) sites during 2019–2021. The results indicate that VMF1-FC-forecasted Tm shows a relatively low RMSE but a relatively large bias (0.75 K) relative to the widely used Global Pressure and Temperature 3 (GPT3) model. To improve the accuracy of VMF1-FC-forecasted Tm, three refined models, XTm, LTm, and CTm, are developed using Extreme Gradient Boosting (XGBoost), Light Gradient Boosting Machine (LightGBM), and Categorical Boosting (CatBoost), respectively, based on observations from 319 RS sites. The models use longitude, latitude, ellipsoidal height, floating day of year (fdoy), and VMF1-FC Tm as input features, and RS Tm as the target variable. Validation using RS data from 2022 that are not involved in model development shows that the refined models significantly reduce bias, with biases of 0 K, 0 K, and −0.03 K for XTm, LTm, and CTm, respectively. Benefiting from the effective reduction in bias, the root mean square error (RMSE) is correspondingly reduced. The RMSEs of XTm, LTm, and CTm are 1.45 K, 1.45 K, and 1.46 K, respectively, achieving improvements of 18.50%/64.93%, 18.44%/64.91%, and 18.11%/64.76% compared with the VMF1-FC and GPT3 models. In addition, three refined models demonstrate higher accuracy and improve stability across different latitude bands, ellipsoidal height ranges, and temporal scales. The refined models provide more accurate global-scale Tm and offer strong potential for GNSS meteorological applications, particularly real-time GNSS-based PWV sensing and weather forecasting. Full article

Lago Argentino and Lago Viedma are large lakes fed by glaciers in Southern Patagonia, characterized by extraordinarily strong, persistent westerly winds and sharp gradients in regional relief, climate, and gravity field. We present operational models of spatio-temporal lake-level variations that represent instantaneous ellipsoidal lake-surface height as the superposition of three components: (i) a time-averaged lake-level topography derived from geoid modeling and ICESat-2 residuals, (ii) temporally varying water-volume changes in the lake estimated from tide gauge time series corrected for atmospherically driven perturbations, and (iii) a static hydrodynamic response to wind stress and air-pressure forcing. The atmospheric response is parametrized through empirically derived transfer functions obtained by regressing instantaneous lake-level anomalies against ERA5 wind and pressure fields, capturing wind-driven tilting. Standard deviations of ICESat-2 ATL13 elevations amount to 106 cm and 70 cm over Lago Argentino and Lago Viedma, respectively. The subtraction of our models reduces these standard deviations to 8 cm (Argentino) and 14 cm (Viedma). Surface waves incompletely averaged out within ICESat-2’s narrow footprint are identified as a principal source for the residual variability. A standard deviation of ATL13 elevations below 2 cm on calm days demonstrates ICESat-2’s unprecedented capability of monitoring water resources from space in a region of sparse hydrological infrastructure. Full article

Height anomaly, defined as the separation between the quasi-geoid and the reference ellipsoid, is fundamental to quasi-geoid refinement. While the Goddard Mars Model-3 (GMM-3) developed by NASA’s Goddard Space Flight Center (GSFC) and the JPL Mars gravity field MRO120D (JGMRO_120D) model developed by NASA’s Jet Propulsion Laboratory (JPL) stand as two representative Martian gravity field models, the systematic differences between them and their associated physical implications remain insufficiently quantified. This study establishes a validated computational framework for Martian height anomaly determination using updated physical parameters and spherical harmonic expansions. Validation against terrestrial datasets confirms high reliability (standard deviation: 0.0695 m relative to International Centre for Global Earth Models (ICGEM)), ensuring confidence in subsequent analysis. Our analysis reveals three critical findings: (1) Systematic latitudinal biases between GMM-3 and JGMRO_120D exhibit a monotonic gradient from −1.3 m near the equator to +3.9 m at the North Pole, suggesting differential parameterization of polar mass loading or tidal models between the two centers. (2) Polar clustering of uncertainties and outliers exceeding the 95th percentile (>7 m) concentrate non-randomly at latitudes >60°, which is attributed to sparse satellite tracking and seasonal ice cap modeling limitations. (3) There is error amplification in lowland terrains, where relative errors exceed 60% in flat regions (near-zero anomalies), posing critical risks for precision landing missions. While global consistency between models is high (R² = 0.9999), the identified discrepancies provide new constraints on Mars’s geophysical models and essential guidance for future gravity field improvements and mission planning. Full article

Pathologic myopia has become a major global cause of blindness, making timely surgical management for myopic traction maculopathy (MTM) increasingly important. This study aimed to identify prognostic factors associated with functional and anatomical outcomes following surgery for MTM and to determine the optimal timing for intervention. This retrospective study included 33 eyes from 28 patients with MTM without full-thickness macular hole who underwent pars plana vitrectomy with internal limiting membrane peeling and gas tamponade. Better preoperative best-corrected visual acuity (BCVA) and lower foveal height were associated with better postoperative BCVA, whereas longer axial length, higher MTM, and higher Atrophy–Traction–Neovascularization (ATN) classification grade were correlated with thinner postoperative central foveal thickness. Foveal detachment (FD), ellipsoid zone (EZ) disruption, and advanced MTM grade were associated with poorer functional and anatomical outcomes. Postoperative visual outcomes should be interpreted with caution, as they may have been influenced by lens-related factors, including combined cataract surgery, post-vitrectomy cataract progression, and posterior capsule opacity. Nonetheless, consistent anatomical improvement was observed, supporting early surgical consideration in eyes with MTM showing progressive macular traction or EZ disruption, even in the absence of FD. These findings highlight the importance of serial OCT monitoring and individualized surgical timing based on preoperative assessments. Full article

Accurate assessment of tunnel lining deformations and stress distributions critically governs structural integrity, while miscalculations may trigger construction delays and budget overruns. A mechanical shell model for tunnel supports was developed, integrating the modified ellipsoid theory to analytically resolve vertical displacements and internal stresses. Numerical validation through finite element simulations confirmed model efficacy. The influence of key geometric and material parameters encompassing height-to-width ratio, burial depth, lining thickness, and elastic modulus on tunnel support displacement and stress distributions was systematically investigated. Parametric analysis revealed that vertical displacement exhibited greater sensitivity to height-to-width ratio variations compared to burial depth. Longitudinal distributions demonstrated similar trends axial force and vertical displacement, with bending moments and shear forces exhibiting analogous behavioral patterns. Transver sely, axial forces and vertical displacements adopted a symmetrical trough (U-shaped) profile, while bending moments and shear forces formed a bimodal (M-shaped) distribution with attenuated gradients near the crown region. This computational model establishes a practical analytical tool for evaluating post-support tunnel deformation and structural load distributions. Full article

In precision agriculture, accurate, non-destructive estimation of fruit volume is crucial for quality grading, yield prediction, and post-harvest management. While vision-based methods provided some usefulness, fruits with complex geometry—such as mangosteen (Garcinia mangostana L.)—are difficult due to their large calyx, which may lead to difficulties in solving using traditional form-modeling methods. Traditional geometric solutions such as ellipsoid approximations, diameter–height estimation, and shape-from-silhouette reconstruction often fail because the irregular calyx generates asymmetric protrusions that violate their basic form assumptions. We offer a novel study framework employing both multi-view instance segmentation and hybrid geometrical feature modeling to quantitatively model mangosteen volume with traditional 2D imaging. A You Only Look Once (YOLO)-based segmentation model was employed to explicitly separate the fruit body from the calyx. Calyx inclusion resulted in dense geometric noise and reduced model performance ($R^2<0.40$). We trained eight regression models on a curated and augmented 900 image dataset ($N=720$, test $N=180$). The models used single-view and multi-view geometric regressors ($V\propto A^{1.5}$), polynomial hybrid configurations, ellipsoid-based approximations, as well as hybrid feature formulations. Multi-view models consistently outperformed single-view models, and the average predictive accuracy improved from $R^2=0.6493$ to $R^2=0.7290$. The best model is indeed a hybrid linear regression model with side- and bottom-area features—($A_s^{1.5}$, $A_b^{1.5}$)—combined with ellipsoid-derived volume estimation—($V_{\mathrm{ellipsoid}}$)—which resulted in $R^2=0.7290$, a Mean Absolute Percentage Error (MAPE) of 16.04%, and a Root Mean Square Error (RMSE) of 31.9 ${\mathrm{cm}}^3$ on the test set. These results confirm the proposed model as a low-cost, interpretable, and flexible model for real-time fruit volume estimation, ready for incorporation into automated sorting and grading systems integrated in post-harvest processing pipelines. Full article

The paper presents a proposal for a simple method of transforming initial GNSS vectors into a spatial local conventional reference frame. This transformation can serve as an alternative to the complex traditional procedure, which involves projecting coordinates onto a reference ellipsoid, mapping them onto a plane of an official local reference frame, and converting ellipsoidal heights into a system of orthometric heights. Local vectors (increments in horizontal coordinates and height differences) are often used in land surveying to analyse relative ground displacement, for example. The article offers a detailed definition of a local conventional reference frame and discusses its potential value for surveying practice. The proposed computation procedure was verified using a control network established to monitor displacement in a mining area. The calculated values of vector components in the local conventional reference frame were compared with the results of the traditional method for transforming GNSS vectors into official local reference frames (the PL-2000 coordinate system and the PL-EVRF2007-NH vertical reference frame). The results of both methods were verified against reference values from typical terrestrial surveys (electronic distance measurement and high-precision geometric levelling). The analysis demonstrates that the proposed numerical procedure is appropriate for control networks with certain areal limitations (up to about 300 m). Full article

Ports pose distinctive monitoring challenges due to harsh marine conditions, mixed construction typologies, and heterogeneous ground conditions. These factors complicate the routine use of satellite InSAR, especially when medium-resolution scatterers must be reliably attributed to specific assets for risk and asset management decisions. In current practice, persistent and distributed scatterer (PS/DS) points are often interpreted in map view without an explicit positional uncertainty model or systematic linkage to three-dimensional infrastructure geometry. We present an end-to-end Differential InSAR framework tailored to large ports that fuses medium-resolution Sentinel-1 Level 2 Co-registered Single-Look Complex (L2-CSLC) stacks with high-resolution airborne LiDAR at the post-processing stage. For the Port of Bahía de Algeciras (Spain), we process 123 Sentinel-1A/B images (2020–2022) in ascending and descending geometry using PS/DS time-series analysis with ETAD-like timing corrections and RAiDER tropospheric/ionospheric mitigation. LiDAR is then used to (i) derive look-specific shadow/layover masks and (ii) perform a whitening-transformed nearest-neighbor association that assigns PS/DS points to LiDAR points under an explicit range–azimuth–cross-range (RAC) uncertainty ellipsoid. The RAC standard deviations $({\sigma }_r,{\sigma }_a,{\sigma }_c)$ are derived from the effective CSLC range/azimuth resolution and from empirical height correction statistics, providing a geometry- and data-informed prior on positional uncertainty. Finally, we render dual-geometry red–green composites (ascending to R, descending to G; shared normalization) on the LiDAR point cloud, enabling consistent inspection in plan and elevation. Across asset types, rigid steel/concrete elements (trestles, quay faces, and dolphins) sustain high coherence, small whitened offsets, and stable backscatter in both looks; cylindrical storage tanks are bright but exhibit look-dependent visibility and larger cross-range residuals due to height and curvature; and container yards and vessels show high amplitude dispersion and lower temporal coherence driven by operations. Overall, LiDAR-assisted whitening-based linking reduces effective positional ambiguity and improves structure-specific attribution for most scatterers across the port. The fusion products, geometry-aware linking plus three-dimensional dual-geometry RGB, enhance the interpretability of medium-resolution SAR and provide a transferable, port-oriented basis for integrating deformation evidence into risk and asset management workflows. Full article