1,148 research outputs found

    Lightweight Image Inpainting by Stripe Window Transformer with Joint Attention to CNN

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    Image inpainting is an important task in computer vision. As admirable methods are presented, the inpainted image is getting closer to reality. However, the result is still not good enough in the reconstructed texture and structure based on human vision. Although recent advances in computer hardware have enabled the development of larger and more complex models, there is still a need for lightweight models that can be used by individuals and small-sized institutions. Therefore, we propose a lightweight model that combines a specialized transformer with a traditional convolutional neural network (CNN). Furthermore, we have noticed most researchers only consider three primary colors (RGB) in inpainted images, but we think this is not enough. So we propose a new loss function to intensify color details. Extensive experiments on commonly seen datasets (Places2 and CelebA) validate the efficacy of our proposed model compared with other state-of-the-art methods. Index Terms: HSV color space, image inpainting, joint attention, stripe window, transformerComment: 6 pages and 5 images, contributions to MLSP 202

    Dynamic analysis in a micro drilling process with ultrasonic vibration

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    In recent years, the processing technology of advanced machinery has toward precision, high-performance, and high-speed. Therefore micro-fabrication becomes more important such as the getting smaller aperture in the printed circuit board (PCB), it tends to be more severe due to vibration. The vibration has adverse effects to machining accuracy and surface roughness which will increase tool abrasion and further accelerate the destruction from material fatigue. There are many ways to produce perforations, such as laser micro-machining and micro-drilling. The industry still adopts micro drill piercing process due to the cost and technical considerations. In order to enhance the cutlery life and the quality of the drilling process, the cutting characteristic of bur is important. Hence, the vibration during drilling must be suppressed. This study is to investigate the dynamic analysis of a micro drill under ultrasonic vibration (50 kHz) excited with a piezoelectric-driven actuator experimentally and numerically by using finite element analysis. The results show that the vibration and the cutting forces are effectively reduced and thereby the cutting performance is improved when introduces ultrasonic vibrations during micro-drilling process

    State-to-state methane-surface scattering as a probe of catalytic activity

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    Quantum state-resolved scattering experiments for methane molecules colliding with a catalytically active nickel surface are compared to scattering from a nickel surface passivated by a single layer of graphene. The vibrational state distribution of the scattered methane is observed to differ dramatically for the two surfaces. Quantum-mechanical inelastic scattering calculations show that these differences are related to the catalytic activity of the surface impact site. Our results demonstrate how inelastic scattering can be used to probe the reactive potential-energy surfaces of molecule-metal systems important to heterogeneous catalysis

    Design and Mechanical Compatibility of Nylon Bionic Cancellous Bone Fabricated by Selective Laser Sintering

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    In order to avoid the stress shielding phenomenon in orthopedic bionic bone implantation, it is necessary to consider the design of mechanical compatible implants imitating the host bone. In this study, we developed a novel cancellous bone structure design method aimed at ensuring the mechanical compatibility between the bionic bone and human bone by means of computer-aided design (CAD) and finite element analysis technology (specifically, finite element modeling (FEM)). An orthogonal lattice model with volume porosity between 59% and 96% was developed by means of CAD. The effective equivalent elastic modulus of a honeycomb structure with square holes was studied by FEM simulation. With the purpose of verifying the validity of the cancellous bone structure design method, the honeycomb structure was fabricated by selective laser sintering (SLS) and the actual equivalent elastic modulus of the honeycomb structure was measured with a uniaxial compression test. The experimental results were compared with the FEM values and the predicted values. The results showed that the stiffness values of the designed structures were within the acceptable range of human cancellous bone of 50-500 MPa, which was similar to the stiffness values of human vertebrae L1 and L5. From the point of view of mechanical strength, the established cellular model can effectively match the elastic modulus of human vertebrae cancellous bone. The functional relationship between the volume porosity of the nylon square-pore honeycomb structure ranging from 59% to 96% and the effective elastic modulus was established. The effect of structural changes related to the manufacture of honeycomb structures on the equivalent elastic modulus of honeycomb structures was studied quantitatively by finite element modeling

    Integration of Genetic Programming and TABU Search Mechanism for Automatic Detection of Magnetic Resonance Imaging in Cervical Spondylosis

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    Cervical spondylosis is a kind of degenerative disease which not only occurs in elder patients. The age distribution of patients is unfortunately decreasing gradually. Magnetic Resonance Imaging (MRI) is the best tool to confirm the cervical spondylosis severity but it requires radiologist to spend a lot of time for image check and interpretation. In this study, we proposed a prediction model to evaluate the cervical spine condition of patients by using MRI data. Furthermore, to ensure the computing efficiency of the proposed model, we adopted a heuristic programming, genetic programming (GP), to build the core of refereeing engine by combining the TABU search (TS) with the evolutionary GP. Finally, to validate the accuracy of the proposed model, we implemented experiments and compared our prediction results with radiologist’s diagnosis to the same MRI image. The experiment found that using clinical indicators to optimize the TABU list in GP+TABU got better fitness than the other two methods and the accuracy rate of our proposed model can achieve 88% on average. We expected the proposed model can help radiologists reduce the interpretation effort and improve the relationship between doctors and patients

    Vibrational Energy Redistribution in a Gas-Surface Encounter: State-to-State Scattering of CH4 from Ni(111)

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    The fate of vibrational energy in the collision of methane (CH4) in its antisymmetric C-H stretch vibration (ν3) with a Ni(111) surface has been studied in a state-to-state scattering experiment. Laser excitation in the incident molecular beam prepared the J 1⁄4 1 rotational state of ν3, and a bolometer in combination with selective laser excitation detected the scattered methane. The rovibrationally resolved scattering distributions reveal very efficient vibrational energy redistribution from ν3 to the symmetric C-H stretch vibration (ν1). The branching ratio ν1=ν3 is near 0.4 and insensitive to changes in incident kinetic energy in the range from 100 to 370 meV. State-resolved angular distributions and measurements of the residual Doppler linewidths prove that the scattering is direct. The observed vibrationally inelastic scattering provides direct experimental evidence for surface-induced vibrational energy redistribution

    Fast-MC-PET: A Novel Deep Learning-aided Motion Correction and Reconstruction Framework for Accelerated PET

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    Patient motion during PET is inevitable. Its long acquisition time not only increases the motion and the associated artifacts but also the patient's discomfort, thus PET acceleration is desirable. However, accelerating PET acquisition will result in reconstructed images with low SNR, and the image quality will still be degraded by motion-induced artifacts. Most of the previous PET motion correction methods are motion type specific that require motion modeling, thus may fail when multiple types of motion present together. Also, those methods are customized for standard long acquisition and could not be directly applied to accelerated PET. To this end, modeling-free universal motion correction reconstruction for accelerated PET is still highly under-explored. In this work, we propose a novel deep learning-aided motion correction and reconstruction framework for accelerated PET, called Fast-MC-PET. Our framework consists of a universal motion correction (UMC) and a short-to-long acquisition reconstruction (SL-Reon) module. The UMC enables modeling-free motion correction by estimating quasi-continuous motion from ultra-short frame reconstructions and using this information for motion-compensated reconstruction. Then, the SL-Recon converts the accelerated UMC image with low counts to a high-quality image with high counts for our final reconstruction output. Our experimental results on human studies show that our Fast-MC-PET can enable 7-fold acceleration and use only 2 minutes acquisition to generate high-quality reconstruction images that outperform/match previous motion correction reconstruction methods using standard 15 minutes long acquisition data.Comment: Accepted at Information Processing in Medical Imaging (IPMI 2023

    Serious Complication of Cement Augmentation for Damaged Pilot Hole

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    Polymethl methacrylate (PMMA) screw reinforcement is frequently used in osteoporotic bone as well as in damaged pilot holes. However, PMMA use can be dangerous, since the amount of applied cement is uncontrolled. A 47-year-old male with traumatic cervical spondylolisthesis at C6-7 underwent anterior cervical plate fixation. During repeated drilling and tapping for false trajectory correction, a pilot hole was damaged. Although it was an unconventional method, PMMA augmentation was tried. However, PMMA was accidentally injected to the cervical spinal cord owing to lack of fluoroscopic guidance. The PMMA was surgically removed after corpectomy and durotomy. The patient had left side hemiparesis (Grade 2/5) immediately post operation. The patient improved spontaneously (Grade 4/5) except for 4th and 5th digit extension. Here, we report a rare complication of PMMA extrusion in the spinal cord during a damaged pilot hole injection, which has not previously been described

    Microwave Accelerated Transglycosylation of Rutin by Cyclodextrin Glucanotransferase from Bacillus sp. SK13.002

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    Rutin was subjected to intermolecular transglycosylation assisted with microwave irradiation using cyclodextrin glucanotransferase (CGTase) produced from Bacillus sp. SK13.002. Compared with the conventional enzymatic method for rutin transglycosylation (without microwave irradiation), microwave-assisted reaction (MAR) was much faster and thus more efficient. While the conventional reaction took dozens of hours to reach the highest conversion rate of rutin and yield of transglycosylated rutin, MAR of rutin transglycosylation completed within only 6 min providing almost the same conversion rate of rutin and yield of products consisting of mono-, di-, tri-, tetra-, penta-glucosylated rutins. The optimum transglycosylation conditions for microwave irradiation were 40 °C and 60 W with the reaction system consisting mainly of the mixture of 0.3 g rutin (0.49 mmol) pre-dissolved in 15 mL methanol, 1.8 g maltodextrin in 15 mL of 0.2 M sodium acetate buffer (pH 5.5) and CGTase (900 U). Results from this study indicated that MAR could be a potentially useful and economical technique for a faster and more efficient transglycosylation of rutin
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