512 research outputs found

    APPLICATION OF HIGH SPEED PANNING ON THE TECHNICAL ANALYSIS OF POLE VAULT

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    INTRODUCTION: The pole vault is an event with the characteristics of a complicated technical movement and a large motion space. Generally, its field of view needs a near 10m horizontal shooting scope and an above 6m vertical shooting scope. The factors such as the edge distortion should be also considered. If the fixed photography of 16mm high-speed camera is used, the image formation is too small to read photographic images. Therefore, the high speed panning of a 35mm camera has been used to record the performance of an elite Chinese pole-vault athlete. On the basis of the shooting film of his movement in competitions, a biomechanical analysis and diagnosis have been made in order to put forward constructive suggestions for the coach and athlete to assist with specific training to improve technique

    A study of evacuation efficiency of a hopper-shape exit by using mice under high competition

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    Exit is the bottleneck of an evacuation from a room and the flow rate through an exit is believed to be depended on its width. A series of experiments were conducted in a bi-dimensional container where mice were driven to pass through two kinds of exit of the identical width, i.e., a conventional exit and a hopper-shape exit. The evacuation efficiency of the two exits was experimentally compared by using mice under competition. The results showed that a hopper-shape exit reduces the escape time by 25% compared with a conventional exit. Further study was conducted with the presence of a column in front of the two exits. The presence of a column in front of the conventional exit increases the escape time by 22.5%. On the contrary, the placement of column in front of the hopper-shape exit reduces the escape time by 48%. The study showed that the escape efficiency could be greatly improved by appropriately redesigning configuration of exit

    Efficient LoFTR: Semi-Dense Local Feature Matching with Sparse-Like Speed

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    We present a novel method for efficiently producing semi-dense matches across images. Previous detector-free matcher LoFTR has shown remarkable matching capability in handling large-viewpoint change and texture-poor scenarios but suffers from low efficiency. We revisit its design choices and derive multiple improvements for both efficiency and accuracy. One key observation is that performing the transformer over the entire feature map is redundant due to shared local information, therefore we propose an aggregated attention mechanism with adaptive token selection for efficiency. Furthermore, we find spatial variance exists in LoFTR's fine correlation module, which is adverse to matching accuracy. A novel two-stage correlation layer is proposed to achieve accurate subpixel correspondences for accuracy improvement. Our efficiency optimized model is 2.5×\sim 2.5\times faster than LoFTR which can even surpass state-of-the-art efficient sparse matching pipeline SuperPoint + LightGlue. Moreover, extensive experiments show that our method can achieve higher accuracy compared with competitive semi-dense matchers, with considerable efficiency benefits. This opens up exciting prospects for large-scale or latency-sensitive applications such as image retrieval and 3D reconstruction. Project page: https://zju3dv.github.io/efficientloftr.Comment: CVPR 2024; Project page: https://zju3dv.github.io/efficientloft

    Weight of Evidence Method and Its Applications and Development

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    AbstractThe development and applications about the weight of evidence technology in recent years are reviewed. This paper introduced the improved weight of evidence in remote sensing image processing and in different fields of application. Summary its constraints and existent problems. Look forward to the weight of evidence for the practical application

    Sevoflurane ameliorates doxorubicin-induced myocardial injury by affecting the phosphorylation states of proteins in PI3K/Akt/mTOR signaling pathway

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      Background: The effect of sevoflurane on the doxorubicin-induced myocardial injury was explored by investigating the phosphorylation states of proteins in phosphatidylinositol 3-kinase (PI3K)/Akt/mam­malian target of rapamycin (mTOR) signaling pathway. Methods: Myocardial injury rat models were induced by doxorubicin and evenly assigned into five groups according to different treatment: Doxorubicin group (DG, 200-μL saline solution), sevoflurane group (SevG, inhaled with 2.4% sevoflurane for 2 h), LY294002 group (LYG, Akt inhibitor, 0.3 mg/kg in 200-μL Dimethyl Sulfoxide [DMSO]), solvent DMSO control group (SG) and autophagy inhibitor 3-methyladenine (3-MA) group (MG, 30 mg/kg in 200-μL DMSO). The healthy rats were assigned to a contro1 group (CG, 200-μL saline solution). Myocardial apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. The concentration of cardiac troponin I (cTnI) was detected by ELISA. The levels of total Akt (t-Akt), phosphorylated Akt (p-Akt), mammalian target of rapamycin (mTOR), phosphorylated-mTOR (p-mTOR) and autophagy marker LC3-II was detected by Western Blot. The experiments were also repeated at the cell level. Results: Terminal deoxynucleotidyl transferase dUTP nick end labeling analysis showed that the ap­optosis rates were high in DG and SG, reached the highest level in LYG, reduced in SevG and MG, and reached the lowest level in CG. The levels of p-Akt p-mTOR were low in groups DG and SG, reached the lowest level in LYG, increased in SevG and MG, and reached the highest level in CG. In contrast, LC3-II expression, apoptosis index and serum cTnI concentration were high in DG and SG, reached the highest level in LYG, reduced in SevG and MG, and reached the lowest level in CG (p < 0.05). Cell experiment showed similar results as with animal experiments. Conclusions: Sevoflurane ameliorates myocardial injury by affecting the phosphorylation states of the proteins in PI3K/Akt/mTOR signaling pathway and reducing the injury biomarker. (Cardiol J 2017; 24, 4: 409–418

    BIOMECHANICS ANALYSIS OF "BRUSH KNEE AND TWIST STEPS" MOVEMENT IN TAI CHI

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    The purpose of this study was to analyze the biomechanical characteristics of a typical Tai Chi (TC) movement - "brush knee and twist steps". A 3-Dimensional fixed video filming method was used for data collection. Three elite professional athletes of TC performed this movement three times and the best one was selected for analysis. The kinematics data included the distance of hands and feet, the angle between the feet, the joint angles of wrist, elbow and knee, the 3-dimensional displacement, velocity and acceleration of CG. The analysis showed that TC exercise could enhance the lower extremity muscular strength movement coordination, and the neuromuscular control for posture and balance
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