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关键词： 3D reconstruction   boundary marking   CAD   geometric accuracy   photogrammetry   reverse engineering  

摘要： Photogrammetric modelling, a widely used technique for reconstructing 3D models from photographic data, relies on achieving high geometric accuracy to minimize post-processing efforts. This study proposes an enhancement to the photogrammetric reconstruction workflow through the introduction of the Boundary Marking Technique. By visibly marking the edges surrounding object surfaces, this method aims to improve edge definition and overall reconstruction quality. The technique was applied to both metal and plastic objects of identical geometry. 3D models were generated using close-range photogrammetry for both marked and unmarked versions, and deviation analyses were conducted against their CAD references. A total of 16 analyses comprising one 3D and three 2D per object were performed using computer-aided comparison tools. Results indicate that the Boundary Marking Technique significantly enhances geometric accuracy, particularly along edges and adjacent surfaces, ultimately improving model topology and dimensional fidelity across the entire reconstruction.

关键词： drive cycles   electric vehicles (EVs)   induction machine (IM)   interior permanent magnet synchronous machine (i-PMSM)   steady state thermal analysis   transient thermal analysis  

摘要： A comparative thermal performance study is carried out on an induction machine (IM) and an interior permanent magnet synchronous machine (i-PMSM) for electric vehicle applications under the standardized Highway Fuel Economy Test (HWFET) and Worldwide Harmonized Light Vehicles Test Procedure (WLTP) Class 3 drive cycles, using ANSYS Motor-CAD in this paper. To allow a fair comparison of steady state and transient thermal behavior, identical cooling boundary conditions were set while considering a consistent electromagnetic thermal modeling framework. The results show that i-PMSM has lower total losses (2.265 kW) than the IM (3.37 kW) under representative drive cycle operating conditions, since there are no rotor copper losses involved. In the case of operation during WLTP Class 3, peak stator winding temperatures reached 173.3 degrees C and 133.6 degrees C for the IM and i-PMSM, respectively, with substantially larger thermal stresses in the IM. From this, it can be seen that the transient thermal response exhibited by i-PMSM was much smoother, with reduced temperature oscillations under dynamic loading, whereas the thermal fluctuation of the IM was significant during frequent acceleration and deceleration events. Although peak efficiency regions above 97% have been observed in both machines at specific torque-speed combinations, drive-cycle-integrated loss behavior has shown that i-PMSM maintains lower overall thermal burden across the investigated operating conditions. These findings consequently bring to the fore the importance of drive cycle dependent thermal evaluation in electric vehicle motor selection and reveal that while the IM has strong benefits regarding robustness and cost, i-PMSM will have superior thermal efficiency and stability during realistic driving scenarios. The presented comparative framework offers practical insights into traction motor design and technology selection in electric vehicle applications.

关键词： Conjugate cams   clearance collisions   lubrication   cam wear   dynamic characteristics  

摘要： Conjugate cams are widely used in the beating-up mechanism of modern high-speed rapier looms, and the collision and friction between the cams and rollers significantly impact the service life of the cams. To investigate the relationships among cam rotation speed, clearance collision, and lubrication wear, the conjugate cam beating-up mechanism was selected as the research object. A dynamic model for clearance collision of conjugate cam pairs was established, and cam wear under different working conditions was simulated and calculated based on the Archard adhesion wear model. The research results indicate that as the driving speed increases, the cam impact force also increases accordingly, leading to increased cam wear. Additionally, an increase in cam clearance can raise the peak contact load between the cam and the roller, resulting in an increase in the peak depth of cam wear. By establishing a model and comprehensively analyzing the effects of speed and clearance, important theoretical basis is provided for predicting and enhancing the service life of conjugate cams.

关键词： Random access memory   Circuits   Logic   Transistors   Optimization   Nonvolatile memory   Integrated circuit reliability   MOS devices   Layout   Arrays   Content addressable memory (CAM)   embedded dynamic random access memory (eDRAM)   logic-in-memory   Boolean logic operation  

摘要： Content-addressable memory (CAM) is regarded as an attractive solution for data-intensive applications with high-density search demands. To further improve functional flexibility yet at a low cost, several CAM macros have been developed to support multiple bit-wise logic operations. However, conventional SRAM-based CAM designs are constrained by the large bitcell area, posing significant challenges to achieve higher density. To address this issue, we propose a complementary 3T (C3T) based embedded dynamic random access memory (eDRAM) macro for high-density dual-direction CAM searching and logic-in-memory operations. First, we propose a compact C3T bitcell featuring a pair of complementary decoupled read ports, enabling dual-port read and efficient CAM operations. Second, we present a compact dynamic-circuit-based sense amplifier (DSA) to optimize the area of readout peripheral circuitry while mitigating the read bit line saturation issue. Additionally, we implement dual-direction CAM searching and logic-in-memory operations exploiting the C3T-based eDRAM macro. A 4 Kb C3T-based eDRAM macro has been validated in a commercial 40-nm CMOS process. Post-layout results demonstrate a 53% reduction in the bitcell area and a 58.1% reduction in the macro area compared to the state-of-the-art 6T compute SRAM. Moreover, the proposed design achieves a maximum frequency of 578 MHz for binary CAM (BCAM) searching operations and 694 MHz for logic operations, with energy consumption of 1.12 fJ/bit and 26.8 fJ/bit, respectively.

关键词： Activated charcoal   Whitening toothpaste   Toothbrushing simulation   CAD/CAM   Hybrid ceramic   Feldspathic ceramic   Lithium disilicate ceramic   Resin nanoceramic   Surface roughness   Digital volumetric loss  

摘要： Objective Activated charcoal (AC) toothpaste has gained popularity for its whitening properties. However, its abrasive effect on computer-aided design and computer-aided manufacturing (CAD/CAM) surfaces compared to conventional whitening toothpaste (WH) remains unclear. This study aimed to evaluate and compare the abrasive impact of AC and WH toothpastes on the surfaces of CAD/CAM materials. Materials and methods A total of ninety-six specimens were prepared from four different types of CAD/CAM materials: Feldspathic ceramic (Vita Mark II, Group VM), lithium disilicate-reinforced glass ceramic (IPS *** CAD, Group EMC), polymer-infiltrated network hybrid ceramic (Vita Enamic, Group VE), and resin nanoceramic (Lava Ultimate, Group LU). Each specimen was prepared to a thickness of 2 mm and manually polished. Initial surface roughness was determined with profilometric analyses. The materials were then divided into subgroups (n = 8) based on three different brushing mediums: distilled water (DW), whitening toothpaste (WH), and activated charcoal toothpaste (AC). A toothbrushing simulator was used to simulate short-term (10,000 cycles-10k, about 1 year) and long-term (30,000 cycles-30k, about 3 years) brushing. After simulation, roughness measurements were repeated on the brushed surfaces, and changes in surface topography were evaluated using scanning electron microscopy images. Volumetric loss was calculated via digital volumetric analyses. Two-way repeated mixed analysis of variance was conducted to assess the effects of material type, brushing medium, and brushing time on the surface roughness, with significance set at alpha = 0.05. Results Group VM exhibited a significant increase in surface roughness after 10k cycles with AC, surpassing the clinical threshold (Ra > 0.2 mu m). EMC showed no change at 10k but demonstrated a statistically significant increase at 30k cycles, also exceeding the threshold. Hybrid ceramics displayed increased roughness values, but all re

关键词： Class activation mapping   Second-order gradient   Differential evolution algorithm   Visual explanation  

摘要： Class activation mapping (CAM) is key to understanding how convolutional neural networks (CNNs) make decisions, but current approaches face considerable challenges. First-order gradient-based methods are often affected by noise and are prone to gradient saturation, leading to less accurate localization. These methods also tend to rely on manual selection and merging of feature maps, limiting their ability to leverage complementary information across network layers and resulting in weaker visual explanations. To address these issues, we propose a smooth second-order gradient class activation mapping (SSG-CAM) method. By incorporating second-order gradients, SSG-CAM captures changes in feature importance to alleviate gradient saturation and integrates a smoothing technique to reduce noise. Additionally, SSG-CAM is integrated with the differential evolution (DE) algorithm to create a collaborative DE-SSG-CAM optimization framework, which automatically screens and fuses the optimal combination of multi-level feature maps. Extensive experiments on multiple benchmark tasks, including weakly supervised object localization and semantic segmentation, demonstrate that our method outperforms existing baselines across various metrics. Notably, the DE-SSG-CAM framework demonstrated a mean Intersection over Union (mIoU) of 62.38% in the complex task of localizing malarial parasite lesions in red blood cells, highlighting its exceptional performance in biomedical image analysis. In this study, we present an accurate and robust visual explanation tool, offering an innovative approach for automatically distilling optimal visual interpretations from deep neural networks.

关键词： Free fibula flap   Reconstructive surgery   Facial reconstruction   Fibula harvesting  

摘要： Background The free fibula flap (FFF) is a cornerstone in facial skeletal reconstruction, but its harvest may be challenging in 5-10% of cases due to concerns over vascularization. While lower limb CT angiography is widely used to assess vascular patency, it involves ionizing radiation and iodinated contrast, posing risks, especially for patients with renal insufficiency or allergies. This study investigates the use of stock fibula models, derived from average anatomical measurements, as a reliable alternative to patient-specific fibulae for surgical planning, thereby eliminating the need for CT angiography. The safeness of fibula harvesting is guaranteed by US color Doppler. Methods A total of 40 fibulas (20 male, 20 female) were analyzed using DICOM data obtained from standard CT scans. Data segmentation and measurement were performed by an open source software (3Dslicer). Results Statistical analysis showed significant differences in fibular dimensions between genders (p < 0.00001), with minimal variability (CV Width M: 8.66%, CV Thickness M: 10.43%, CV Width F: 10.88%, CV Thickness F: 14.43%), confirming the suitability of stock models for accurate reconstructive plans. Importantly, bypassing CT angiography eliminates radiation exposure and the administration of iodinated contrast, reducing patient risks. Conclusions The results suggest that stock fibula models, based on population averages, provide an effective and safe solution for facial reconstruction, ensuring high surgical precision without the need for CT angiography or contrast *** of Evidence: Level III, risk / prognostic study.

关键词： CAD drawing completion   point cloud   curvature-driven   masked Autoencoder  

摘要： The loss of geometric information in computer-aided design (CAD) drawings presents a significant obstacle to creating high-fidelity digital models. To address this, we propose a novel self-supervised completion method. Our approach begins by converting 2D CAD drawings into a structured 3D point cloud, where the geometric attributes of primitives are uniquely encoded into a meaningful depth dimension. At the core of our method is a masked autoencoder framework empowered by a pivotal curvature-driven adaptive mechanism. This mechanism guides the model to intelligently preserve and reconstruct critical details by focusing on high-curvature regions like corners and intersections during both encoding and decoding. Our method demonstrates superior restoration performance across diverse corruption scenarios on the FloorPlanCAD dataset. Furthermore, its learned features show powerful generalization, achieving state-of-the-art 94.01% accuracy on the ModelNet40 classification benchmark.

关键词： Coronary artery disease (CAD)   Stenosis   Coronary computed tomography angiography (CCTA)   Radiomics   CAD-RADS   Machine learning   Atherosclerotic plaque  

摘要： Synthesizing coronary radiomic data to obtain a single patient-wise Coronary Artery Disease-Reporting and Data System (CAD-RADS) score remains challenging. This work proposes four strategies for summarizing radiomic features extracted from 2779 multiplanar reconstruction images derived from coronary computed tomography angiography of 238 patients. A cascade pipeline was developed to train gradient boosting classifiers for CAD-RADS scoring through consecutive tasks, considering 80%-20% training/test split with five-fold cross-validation on the training set. Two statistical-based and two majority voting approaches were implemented to obtain patient-level classification. The former consisted in computing features average, minimum, maximum and standard deviation, across the coronary images, leading to intermediate coronary classification, followed by patient classification according to the worst coronary class. The latter consisted in single image predictions and the application of majority voting either to all the images, to obtain patient classification (MV_P), or to the images of single coronary arteries, followed by patient classification according to the worst coronary class (MV_C). Majority-voting approaches outperformed statistical-based ones, with MV_P achieving an AUC of CAD-RADS_0 = 0.94, CAD-RADS_1 = 0.92, CAD-RADS_2 = 0.97, CAD-RADS_3 = 0.77, CAD-RADS_4 = 0.88, CAD-RADS_5 = 0.85, and MV_C of CAD-RADS_0 = 0.82, CAD-RADS_1 = 0.78, CAD-RADS_2 = 0.84, CAD-RADS_3 = 0.96, CAD-RADS_4 = 0.98 and CAD-RADS_5 = 0.85. This study represents a significant advancement toward robust and reproducible coronary radiomics tools for automated CAD-RADS scoring.