Search Results (245)

The sparse iterative covariance-based estimation (SPICE) method has recently gained significant attraction in the field of scanning radar super-resolution imaging because of its angular resolution enhancement capability. However, it is unable to preserve the target profile, and the estimator is constrained by high computational complexity and memory consumption. In this paper, a grid-updating split SPICE-TV algorithm is presented. The method allows for the efficient updating of reconstruction results with both contour and resolution, and a recursive grid-updating implementation framework of the split SPICE-TV has the capability to reduce the computational complexity. First, the scanning radar angular super-resolution problem is transformed into a constrained optimization problem by simultaneously employing sparse covariance fitting criteria and TV regularization constraints. Then, the split Bregman method is employed to derive an efficient closed-form solution to the problem. Ultimately, the matrix inversion problem is transformed into an online iterative equation to reduce the computational complexity and memory consumption. The superiority of the proposed method is verified by simulation and experimental data. Full article

Purpose: This pilot study aimed to evaluate how deviations in X-ray tube head angulation and digital sensor alignment affect the radiographic measurement of the profile angle in CAD-CAM abutments. Materials and Methods: A mandibular model was used with five implant positions (central, buccal, and lingual offsets). Custom CAD-CAM abutments were designed with identical bucco-lingual direction contours and varying mesio-distal asymmetry for the corresponding implant positions. Periapical radiographs were acquired under controlled conditions by systematically varying vertical tube angulation, horizontal tube angulation, and horizontal sensor rotation from 0° to 20° in 5° increments for each parameter. Profile angles, interthread distances, and proximal overlaps were measured and compared with baseline STL data. Results: Profile angle measurements were significantly affected by both X-ray tube and sensor deviations. Horizontal tube angulation produced the greatest profile angle distortion, particularly in buccally positioned implants. Vertical x-ray tube angulations beyond 15° led to progressive underestimation of profile angles, while horizontal tube head rotation introduced asymmetric mesial–distal variation. Sensor rotation also caused marked interthread elongation, in some cases exceeding 100%, despite vertical projection being maintained. Profile angle deviations greater than 5° occurred in multiple conditions. Conclusions: X-ray tube angulation and sensor alignment influence the reliability of profile angle measurements. Radiographs with > 10% interthread elongation or crown overlap may be inaccurate and warrant re-acquisition. Special attention is needed when imaging buccally positioned implants. Full article

This study proposes an iterative method based on thermal equilibrium equations to calculate the radial temperature distribution of long-span overhead transmission lines under forced convection. This paper takes the ACSR 500/280 conductor as the research object, establishes the three-dimensional finite element model considering the helix angle of the conductor, and carries out the experimental validation for the LGJ 300/40 conductor under the same conditions. The model captures internal temperature distribution through contour analysis and examines the effects of current, wind speed, and ambient temperature. Unlike traditional models assuming uniform conductor temperature, this method reveals internal thermal gradients and introduces a novel three-stage radial attenuation characterization. The iterative method converges and accurately reflects temperature variations. The results show a non-uniform radial distribution, with a maximum temperature difference of 8 °C and steeper gradients in aluminum than in steel. Increasing current raises temperature nonlinearly, enlarging the radial difference. Higher wind speeds reduce both temperature and radial difference, while rising ambient temperatures increase conductor temperature with a stable radial profile. This work provides valuable insights for the safe operation and optimal design of long-span transmission lines and supports future research on dynamic and environmental coupling effects. Full article

Aiming at the problems of the imprecise safety distance standards for low-altitude UAVs within complex low-altitude environments and the difficulty of managing heterogeneous vehicles, a UAV safety interval calibration method based on random heading is proposed. Firstly, a UAV clustering model based on K-Means++ was established for the performance characteristics of UAVs, using evaluation indexes such as contour coefficient, sum of squares of errors, Davidson–Bourdain index, etc. Then, combining this with the characteristics of UAVs with random heading, a UAV safety interval calibration model based on random heading was constructed, and the conflict probability and airspace utilization rate were determined and metered for UAV safety interval calibration. The experimental results showed that the profile coefficient, sum of squares of errors, and Davidson–Berding index of the iteratively optimized UAV clustering were optimized by 53.9%, 55.6%, and 46.6%, respectively, compared with the initial clustering results, and that the safe intervals calibrated in the experimental environment of a single category of UAVs were also applicable to the fusion airspace environment after validation. The research results can provide a theoretical basis and methodological support for the safety interval calibration of UAVs in low-altitude fusion operations. Full article

Background/Objectives: Treatment of locally advanced rectal cancer (LARC) very often requires a neoadjuvant multimodal approach. Neoadjuvant treatment (NAT) encompasses treatments like chemoradiotherapy (CRT), short-course radiotherapy (SCRT), radiotherapy (RT) or a combination of either of these two with additional induction or consolidation chemotherapy, namely total neoadjuvant treatment (TNT). In case of complete radiological and clinical response, the non-operative watch-and-wait strategy can be adopted in selected patients. This strategy is impacted by a regrowth rate of approximately 30%. Predicting biomarkers of tumor response to NAT could improve guidance of clinicians during clinical decision making, improving treatment outcomes and decreasing unnecessary treatment exposure. To this day, there is no validated biomarker to predict tumor response to any NAT strategies in clinical use. Most research focused on CRT neglects the study of other regimens. Methods: We conducted a narrative literature review which aimed at summarizing the status of biomarkers predicting tumor response to NAT other than CRT in LARC. Results: Two hundred and fourteen articles were identified. After screening, twenty-one full-text articles were included. Statistically significant markers associated with improved tumor response pre-treatment were as follows: low circulating CEA levels; BCL-2 expression; high cellular expression of Ku70, MIB-1(Ki-67) and EGFR; low cellular expression of VEGF, hPEBP4 and nuclear β-catenin; the absence of TP53, SMAD4, KRAS and LRP1B mutations; the presence of the G-allel of LCS-6; and MRI features such as the conventional biexponential fitting pseudodiffusion (Dp) mean value and standard deviation (SD), the variable projection Dp mean value and lymph node characteristics (short axis, smooth contour, homogeneity and Zhang et al. radiomic score). In the interval post-treatment and before surgery, significant markers were as follows: a reduction in the median value of circulating free DNA, higher presence of monocytic myeloid-derived suppressor cells, lower presence of CTLA4+ or PD1+ regulatory T cells and standardized index of shape changes on MRI. Conclusions: Responders to neoadjuvant SCRT and RT tended to have a tumor microenvironment with an immune–active phenotype, whereas responders to TNT tended to have a less active tumor profile. Although some biomarkers hold great promise, scarce publications, inconsistent results, low statistical power, and low reproducibility prevent them from reliably predicting tumor response following NAT. Full article

The contact characteristics of radial tires are crucial for optimizing stress distribution, deformation, and wear. The non-uniform contact stress behavior induced by complex tread patterns remains under-explored in existing tire mechanics research. Taking the 205/50R17 radial tire as a representative case, a reverse modeling approach was employed to develop an accurate finite element model for tires incorporating intricate tread pattern features. The fidelity of the proposed tire simulation model was confirmed utilizing high-precision contour profiling techniques. The impact of diverse usage conditions and design parameters on the tire outer profile and ground contact characteristics under static and free-rolling states was analyzed. Experimental observations demonstrate that the increased inflation pressure leads to a proportional decrease in contact area. Under incremental vertical loading, the contact patch develops progressively into a saddle-shaped geometry featuring elevated shoulder regions and a recessed central zone. Increasing the belt angle compromises its hoop-stiffening function, thereby inducing elliptical contact patch geometry. Larger design diameters compromise contact length symmetry in shoulder regions. Variation in shoulder thickness at 85% of the tread width results in a significant difference in contact length between the left and right tread blocks in the rolling state. This work enables refinement strategies for both tread configurations and tire dimensional designs in industrial applications. Full article

An Abramson-type oblique-incident interferometer was used for the surface-form measurement of hand-scraped marks consisting of rough surfaces. Although the Abramson interferometer could measure the rough surface of hand-scraped marks under noncontact conditions, the inconsistency in the measurement results was caused by the differences in the incident direction of the measuring light. This study investigated the inconsistency in the measurement results of the Abramson interferometer caused by the oblique incidence of the measuring light. The reproducibility of inconsistencies due to the difference in the incident direction of the measuring light was confirmed, and the relationship between the inconsistency of the measurement results and the incident angle of the measuring light was investigated. Consequently, it was confirmed that the inconsistency of the measurement results due to the difference in the incident direction of the measuring light could be reduced by decreasing the incident angle of the measuring light. To avoid the overcrowding of the interference fringes caused by the reduction in the incident angle of the measuring light, an oblique-incident interferometer with a near-infrared laser was constructed. The validity of the developed oblique-incident interferometer was evaluated by comparison with a commercially available contour measurement instrument. The surface form obtained by the developed oblique-incident interferometer was confirmed to be consistent with the envelope of the cross-sectional profile measured by the contour measurement instrument. Full article

Background/Objectives: Significant weight loss, whether through bariatric surgery or medication-assisted approaches, presents unique challenges for body contouring procedures. A thorough preoperative evaluation is essential to optimize outcomes and minimize risks. Methods: A comprehensive literature search was conducted across various databases to identify studies on assessment, nutritional optimization, thromboembolic risk, and surgical planning for post-weight-loss patients, with a particular focus on those undergoing medication-assisted weight loss using Glucagon-like peptide-1 (GLP-1) agonists. Results: A detailed review of medical history, comorbidities, weight loss trajectory, and nutritional status is essential. Common conditions such as diabetes, hypertension, and sleep apnea often improve after weight loss but require ongoing management. Nutritional deficiencies, particularly in vitamins and minerals, necessitate dietary counseling and supplementation. Patients who have undergone significant weight loss are at increased risk of thromboembolic events, particularly after body contouring procedures. Surgical planning should be patient-centered, setting realistic expectations and employing a strategic, staged approach when necessary to optimize outcomes. GLP-1 agonists users require special consideration due to their distinct metabolic and physiological profiles. Conclusions: Optimizing preoperative assessment, nutrition, and thromboprophylaxis is critical for safe and effective body contouring in post-weight-loss patients. With the increasing prevalence of medication-assisted weight loss, surgical strategies must adapt to address the distinct anatomical and physiological features of these patients. Full article

Flash LiDAR can be used to capture the depth information or contour profile of a target area in one shot and, therefore, has become an important feature in depth sensing devices. Current flash LiDAR devices still suffer from resolution issues due to difficulties in reducing the pixel size of the array sensor. In this paper, a solution has been proposed to resolve this resolution issue by introducing multi-view imaging optics into the flash LiDAR device. Together with scanning illumination over the target area and range image tiling, a fourfold increase in spatial resolution has been achieved, and the working concept can be further extended for resolution enhancement via array expansion. A calibration procedure and shielding mechanism have also been developed to compensate for the issues of crosstalk and stray light, ensuring the quality of the tiled range image. The prototype and corresponding experiment have demonstrated the feasibility of the proposed architecture as an optical solution for enhancing the resolution of flash LiDAR. Full article

Left ventricle (LV) segmentation is crucial for cardiac diagnosis but remains challenging in echocardiography. We present ShapeNet, a fully automatic method combining a convolutional neural network (CNN) ensemble with an improved active shape model (ASM). ShapeNet predicts optimal pose (rotation, translation, and scale) and shape parameters, which are refined using the improved ASM. The ASM optimizes an objective function constructed from gray-level profiles concatenated into a single contour appearance vector. The model was trained on 4800 augmented CAMUS images and tested on both CAMUS and EchoNet databases. It achieved a Dice coefficient of 0.87 and a Hausdorff Distance (HD) of 4.08 pixels on CAMUS, and a Dice coefficient of 0.81 with an HD of 10.21 pixels on EchoNet, demonstrating robust performance across datasets. These results highlight the improved accuracy in HD compared to previous semantic and shape-based segmentation methods by generating statistically valid LV contours from ultrasound images. Full article

The purpose of infrared and visible image fusion is to generate a composite image that can contain both the thermal radiation profile information of the infrared image and the texture details of the visible image. This kind of composite image can be used to detect targets under various lighting conditions and offer high scene spatial resolution. However, the existing image fusion algorithms rarely consider light factor in the modeling process. The study presents a novel image fusion approach (AIF) that can adaptively fuse infrared and visible images under various lighting conditions. Specifically, the infrared image and the visible image are extracted by the AdC feature extractor, respectively, and both of them are adaptively fused under the guidance of the illumination perception subnetwork. The image fusion model is trained in an unsupervised manner with a customized loss function. The AdC feature extractor adopts an ascending–descending feature extraction mechanism to organize convolutional layers and combines these convolutional layers with cross-modal interactive differential modules to achieve the effective extraction of hierarchical complementary and differential information. The illumination perception subnetwork obtains the scene lighting condition based on the visible image, which determines the contribution weights of the visible image and the infrared image in the composite image. The customized loss function consists of illumination loss, gradient loss, and intensity loss. It is more targeted and can effectively improve the fusion effect of visible images and infrared images under different lighting conditions. Ablation experiments demonstrate the effectiveness of the loss function. We compare our method with nine other methods on public datasets, including four traditional methods and five deep-learning-based methods. Qualitative and quantitative experiments show that our method performs better in terms of indicators such as SD, and the fused image has more prominent contour information and richer detail information. Full article

Multi-jet polishing (MJP) is a promising method for enhanced polishing efficiency by integrating multiple nozzles, allowing for the high-efficiency polishing of large-scale surfaces. However, the optimization of the structural parameters, such as the distribution form of the nozzles and outlet diameter, remains a critical challenge for achieving uniform and stable polishing performance. This paper presents a dynamic model of MJP based on the theory of fluid dynamic pressure and particle erosion. The flow field and particle motion characteristics in multi-nozzle jet polishing were studied using simulation experiments. The influence of the nozzle spacing and form and outlet diameter on the flow field characteristics and material removal profile was explored, and the structural parameters of the multi-nozzle polishing tool were optimized. According to the simulation results, two kinds of multi-nozzle polishing tools with a linear arrangement and cross arrangement were processed, and a series of single-point and surface polishing experiments was carried out. The optimized multi-nozzle jet polishing tool has no interference in the removal contour of each point, exhibits high consistency and stability, and is consistent with the theoretical model prediction results, which effectively improve the surface polishing efficiency. The results can provide a theoretical and experimental reference for MJP in the ultra-precision and high-efficiency polishing of large-sized components. Full article

This study seeks to automate the Rapid Entire Body Assessment (REBA) in dentistry with Artificial Intelligence (AI) technologies, notably MediaPipe, to improve accuracy and obviate the necessity for expert judgment. This research utilizes time-synchronized videos and averages across frames to mitigate mistakes resulting from visual occlusion and over- or underestimation, respectively. The REBA scores of the observed dentists were evaluated and compared with the conventional single image-based method. Among the evaluated dentists, 83% of dentists are at high risk, and the other 17% of dentists are at very high risk, requiring solutions to lower their REBA scores and prevent musculoskeletal disorders (MSDs). The individual REBA point profiles differed, necessitating a collective study through response surface methodology (RSM) utilizing Design Expert software. The RSM model exhibited substantial results, as indicated by R² = 0.9055 and p = < 0.0001 values. A linear regression equation was established, and contour graphs depicted the relative variation of REBA points. The optimized REBA score profile establishes a maximum attainable threshold for dentists, directing them towards the lower scores. This streamlined contour functions as a design restriction for creating ergonomic solutions in dental practice. Full article

This study investigated the enhancement of the mechanical and tribological properties of MWCNT-reinforced bio-based epoxy composites through systematic experiments and analysis. Composites incorporating MWCNTs at varying weight percentages were evaluated for hardness, wear rate, interfacial shear strength, and friction coefficient under diverse load, sliding speed, and distance conditions. An optimal MWCNT content of 0.3–0.4% resulted in a maximum hardness of 4 GPa and a minimum wear rate of 0.0058 mm³/N·m, demonstrating a substantial improvement over the non-reinforced system. FTIR and XRD analyses confirmed robust interfacial bonding between the MWCNTs and epoxy matrix, while molecular dynamics simulations revealed cohesive energy density and stress distribution profiles. The Taguchi optimization identified the MWCNT weight percentage as the most influential parameter, contributing over 85% to wear rate reduction. Contour plots and correlograms further illustrate the parameter interdependencies, emphasizing the role of MWCNT dispersion in enhancing the composite properties. These findings establish that MWCNT-reinforced bio-based epoxy composites are promising candidates for high-performance and sustainable tribological applications. Full article

Background/Objectives: The peri-implant soft tissue seal is crucial for the long-term success of subcrestally placed implants (SPIs). However, conventional biologic width—now referred to as supracrestal tissue attachment (STA)—models, originally developed for natural teeth, fail to account for the three-dimensional nature of peri-implant soft tissue adaptation. This study introduces a novel framework integrating the concepts of the transitional zone (TZ) and subcrestal zone (SZ) to systematically optimize peri-implant soft tissue architecture. Methods: A mathematical model was developed to determine the optimal implant placement depth by incorporating the emergence angle (EA), soft tissue thickness (STT), and peripheral crestal offset (PCO). Additionally, a three-dimensional peri-implant soft tissue analysis (3DSTA) approach utilizing cone beam computed tomography (CBCT) imaging was implemented to evaluate peri-implant soft tissue adaptation and emergence profile design. Clinical parameters were analyzed to establish guidelines for optimizing SPI placement depth and peri-implant soft tissue stability. Results: This study introduces the concept of self-sustained soft tissue (SSST), a biologically functional structure composed of the TZ and SZ, which enhances peri-implant health and stability. The proposed framework provides clinical guidelines for optimizing SPI placement depth, emergence profile contouring, and peri-implant soft tissue thickness to mitigate the risk of peri-implant mucositis. By shifting from a traditional two-dimensional perspective to a multidimensional analysis, this approach offers an evidence-based foundation for achieving biologically stable and esthetically predictable outcomes. Conclusions: The proposed three-dimensional model advances the understanding of peri-implant soft tissue adaptation by integrating novel anatomical and biomechanical concepts. By redefining peri-implant biologic width through the introduction of TZ and SZ, this study provides a structured framework for optimizing SPI placement and soft tissue management. Future research should focus on validating this model through histological studies and long-term clinical trials to refine its application in clinical practice. Full article