A KINEMATIC ANALYSIS OF A TOP 10 WTA TENNIS PLAYER’S FIRST SERVE

The purpose of this study was to provide valuable information of the tennis serve, through a three-dimensional (3D) cinematographic analysis of Li Na’s flat serve. Two high-speed cameras operating at 200Hz placed around the baseline recorded her flat service motion. The direct linear transformation (DLT) method was used. The ball was hit at a distance of 1.11 m below a peak ball toss height of 3.65 m. In backswing, the minimum knee flexion angle was about 110°. The lowest point recorded by the racket head was about 0.21 m lower than the height of the body center of gravity during the early drive phase. The velocity of the racket head was 38.2 m/s at impact and the height of the impact point was 2.5 m which was 1.48 times the height of her body. Like other elite tennis players in the world, Li Na has her own tennis strokes and swing style

A deep learning framework based on Koopman operator for data-driven modeling of vehicle dynamics

Autonomous vehicles and driving technologies have received notable attention in the past decades. In autonomous driving systems, \textcolor{black}{the} information of vehicle dynamics is required in most cases for designing of motion planning and control algorithms. However, it is nontrivial for identifying a global model of vehicle dynamics due to the existence of strong non-linearity and uncertainty. Many efforts have resorted to machine learning techniques for building data-driven models, but it may suffer from interpretability and result in a complex nonlinear representation. In this paper, we propose a deep learning framework relying on an interpretable Koopman operator to build a data-driven predictor of the vehicle dynamics. The main idea is to use the Koopman operator for representing the nonlinear dynamics in a linear lifted feature space. The approach results in a global model that integrates the dynamics in both longitudinal and lateral directions. As the core contribution, we propose a deep learning-based extended dynamic mode decomposition (Deep EDMD) algorithm to learn a finite approximation of the Koopman operator. Different from other machine learning-based approaches, deep neural networks play the role of learning feature representations for EDMD in the framework of the Koopman operator. Simulation results in a high-fidelity CarSim environment are reported, which show the capability of the Deep EDMD approach in multi-step prediction of vehicle dynamics at a wide operating range. Also, the proposed approach outperforms the EDMD method, the multi-layer perception (MLP) method, and the Extreme Learning Machines-based EDMD (ELM-EDMD) method in terms of modeling performance. Finally, we design a linear MPC with Deep EDMD (DE-MPC) for realizing reference tracking and test the controller in the CarSim environment.Comment: 12 pages, 10 figures, 1 table, and 2 algorithm

CDC20, TOP2A and NEK2 Expression in Esophageal Squamous Cell Carcinoma and Its Clinical Significance

Objective: to study the expression and clinical significance CDC20,TOP2A, NEK2 esophageal squamous cell carcinoma. Methods: Toselect 70 patients with esophageal squamous cell carcinoma, Between August 2018 - August 2020, All intraoperative pathological specimens,A group -35 cases), Cancer tissue, B group, adjacent tissues), two groups of CDC20, TOP2A, NEK 2 expression were detected and analyzed by immunohistochemistry and semi-quantitative reverse transcription polymerase chain reaction -RT-PcR) assay.Results: the values of CDC20,TOP2A, NEK2 expression level in A group were significantly higher thanthose in B group -P<0.05). The expression level CDC20, TOP2A, NEK2esophageal squamous cell carcinoma was positively correlated with TNMstage and lymphatic metastasis, and negatively correlated with tumordifferentiation. Conclusion: CDC20, TOP2A, NEK2 high expression leveldirectly affects the metastasis, recurrence and prognosis of esophagealsquamous cell carcinoma. The combination of three indexes can accuratelyevaluate the pathological status of patients with esophageal squamous cellcarcinoma and help to judge the prognosis of patients accuratel

EFFECTS OF TAl CHI EXERCISE ON GAIT PATTERN IN THE ELDERLY

The purpose of this study was to examine the normal walking pattern of 21 older adults who had practiced Tai Chi for more than 5 years (TC group) and 20 older adults who often performed other kinds of physical activity (CTRL group). The results of the study indicated that there were significant differences in kinematic parameters of the hip joint angles, and the curve of ground reaction force versus time between the two groups

Illegal Intrusion Detection of Internet of Things Based on Deep Mining Algorithm

In this study, to reduce the influence of The Internet of Things (IoT) illegal intrusion on the transmission effect, and ensure IoT safe operation, an illegal intrusion detection method of the Internet of Things (IoT) based on deep mining algorithm was designed to accurately detect IoT illegal intrusion. Moreover, this study collected the data in the IoT through data packets and carries out data attribute mapping on the collected data, transformed the character information into numerical information, implemented standardization and normalization processing on the numerical information, and optimized the processed data by using a regional adaptive oversampling algorithm to obtain an IoT data training set. The IoT data training set was taken as the input data of the improved sparse auto-encoder neural network. The hierarchical greedy training strategy was used to extract the feature vector of the sparse IoT illegal intrusion data that were used as the inputs of the extreme learning machine classifier to realize the classification and detection of the IoT illegal intrusion features. The experimental results indicate that the feature extraction of the illegal intrusion data of the IoT can effectively reduce the feature dimension of the illegal intrusion data of the IoT to less than 30 and the dimension of the original data. The recall rate, precision, and F1 value of the IoT intrusion detection are 98.3%, 98.7%, and 98.6%, respectively, which can accurately detect IoT intrusion attacks. The conclusion demonstrates that the intrusion detection of IoT based on deep mining algorithm can achieve accurate detection of IoT illegal intrusion and reduce the influence of IoT illegal intrusion on the transmission effect

Guizhi-jia-houpu-xingzi decoction attenuates ovalbumin-induced allergic asthma via regulation of Toll-like receptor signal pathway

Purpose: To study the effect of Guizhi-jia-houpu-xingzi (GHX) on ovalbumin-induced allergic asthma in rats.Methods: An animal model of allergic asthma (AA) in rats was established by intraperitoneal injection (ip) of ovalbumin (OVA). Thereafter, GHX (375 mg/kg) was administered orally for 7 days. Pulmonary function, inflammatory cells, immunoglobulin E (Ig) E, interleukin-4 (IL)-4 and interferon-γ (IFN)-γ in serum and bronchoalveolar lavage fluids (BALF) were determined. Furthermore, mRNA expressions of Toll-like receptors (TLRs) signal pathway was determined using real time polymerase chain reaction PCR (q-RT-PCR).Results: GHX (375 mg/kg) significantly decreased respiratory rate (p &lt; 0.01) and Penh value (p &lt; 0.05) when compared with AA rats. The inflammatory cells (p &lt; 0.01) and levels of IL-4 (p &lt; 0.01) and IgE (p &lt; 0.01) were significantly decreased by GHX treatment when compared with AA rats; whereas IFN-γ (p &lt; 0.05) was significantly increased. Furthermore, GHX significantly decreased the mRNA expressions of GATA binding protein (GATA)-3 (p &lt; 0.01), TRL-2 (p &lt; 0.01), TRL-4 (p &lt; 0.01), myeloid differentiation factor 88 (MyD88) (p &lt; 0.01), TNF receptor associated factor 6 (TRAF6) (p &lt; 0.01) and β-arrestin (p &lt; 0.01) in lung tissues, relative to AA rats. However, GHX treatment led to significant up-regulation of mRNA expression of T-bet (p &lt; 0.01).Conclusion: These results demonstrate that GHX possesses a potential for treating allergic asthma via regulation of Toll-like receptor (TLR) signal pathway. They also provide a scientific basis for the probable use of GHX in clinical treatment of allergic diseases in future.Keywords: Guizhi-jia-houpu-xingzi decoction, Ovalbumin, Allergic asthma, Toll-like recepto