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Open access

Xiaopeng Wei, Boxiang Xiao, Qiang Zhang and Rui Liu

A Method of Hyper-sphere Cover in Multidimensional Space for Human Mocap Data Retrieval

A method of hyper-sphere cover in multidimensional space for human Mocap (Motion Capture) data retrieval is presented in this paper. After normalization and feature extraction, both the retrieval instance and the motion data are mapping into a multidimensional space. Several hyper-spheres are constructed according to the retrieval instance, and the domain covered by these hyper-spheres can be considered as the distribution range of a same kind of motions. By use of CMU free motion database, the retrieval algorithm has been implemented and examined and the experimental results are illustrated. At the same time, the main contributions and limitations are discussed.

Open access

Fu Qiang, Zhang Benying, Zhao Yuanyuan, Zhu Rongsheng, Liu Gang and Li Mengyuan

Abstract

In the field of ocean engineering, cavitation is widespread, for the study of cavitation nuclei transient characteristics in cavitation inception, we applied theoretical analysis and molecular dynamics (MD) simulation to study Lennard-Jones (L-J) fluid with different initial cavitation nuclei under the NVT-constant ensemble in this manuscript. The results showed that in cavitation inception, due to the decrease of liquid local pressure, the liquid molecules would enter the cavitation nuclei, which contributed to the growth of cavitation nuclei. By using molecular potential energy, it was found that the molecular potential energy was higher in cavitation nuclei part, while the liquid molecular potential energy changes greatly at the beginning of the cavitation nuclei growth. The density of the liquid and the surface layer changes more obvious, but density of vapor in the bubble changes inconspicuously. With the growth of cavitation nuclei, the RDF peak intensity increased, the peak width narrowed and the first valley moved inner. When cavitation nuclei initial size reduced, the peak intensity reduced, the corresponding rbin increased. With the decrease of the initial cavitation nuclei, the system pressure and total energy achieved a balance longer, and correspondingly, they were smaller. In addition, at the beginning of the cavitation nuclei growth, the total energy and system pressure changed greatly.

Open access

Qiang Zhang, Shao-Pei Yu, Dong-Sheng Zhou and Xiao-Peng Wei

Abstract

This paper proposes a novel method of key-frame extraction for use with motion capture data. This method is based on an unsupervised cluster algorithm. First, the motion sequence is clustered into two classes by the similarity distance of the adjacent frames so that the thresholds needed in the next step can be determined adaptively. Second, a dynamic cluster algorithm called ISODATA is used to cluster all the frames and the frames nearest to the center of each class are automatically extracted as key-frames of the sequence. Unlike many other clustering techniques, the present improved cluster algorithm can automatically address different motion types without any need for specified parameters from users. The proposed method is capable of summarizing motion capture data reliably and efficiently. The present work also provides a meaningful comparison between the results of the proposed key-frame extraction technique and other previous methods. These results are evaluated in terms of metrics that measure reconstructed motion and the mean absolute error value, which are derived from the reconstructed data and the original data.

Open access

Jing-guang Qian, Yang Su, Ya-wei Song, Ye Qiang and Songning Zhang

A Comparison of a Multi-body Model and 3D Kinematics and EMG of Double-leg Circle on Pommel Horse

The purpose of this study was to establish a multi-segment dynamic model in the LifeMOD to examine kinematics of the center of mass and foot, and muscle forces of selected upper extremity muslces during a double-leg circle (DLC) movement on pommel horse in gymnastics and compared with three-dimensional kinematics of the movement and surface electromyographic (sEMG) activity of the muscles. The DLC movement of one elite male gymnast was collected. The three-dimensional (3D) data was imported in the Lifemod to create a full-body human model. A 16-Channel surface electromyography system was used to collect sEMG signals of middle deltoid, biceps brachii, triceps brachii, latissimusdorsi, and pectoralis major. The 3D center of mass and foot displacement showed a good match with the computer simulated results. The muscle force estimations from the model during the four DLC phases were also generally supported by the integrated sEMG results, suggesting that the model was valid. A potential application of this model is to help identify shortcomings of athletes and help establish appropriate training plans errors in the DLC technique during training.

Open access

Fu Qiang, Chen Ming, Wang Xiuli, Zhu Rongsheng, Zhang Guoyu and Yu Jianen

Abstract

The micro air nucleus widely distributed in the ocean is a necessary condition for the cavitation of hydraulic machinery in seawater. In order to study the stability of air nucleus in seawater and cavitation inception, the computational domain of water molecules with air nucleus was studied using the method of molecular dynamics simulation, and the transient characteristics of air nucleus in liquid water were obtained. The key factors influencing nuclei stability were analyzed. The results showed that air nucleus with a certain mass could maintain the dynamic equilibrium in liquid water. The internal density of air nuclei had a critical value that allowed the nuclei to stably exist in water. The air nuclei mass was the decisive factor in its equilibrium volume in water, and the two were positively correlated. The internal density of air nuclei was negatively correlated with the nuclei radius when the nuclei was stable in water. Liquid surface tension was an important factor affecting the stability of the air nuclei. The larger the initial radius of nuclei, the smaller the water pressure, and the more likely the cavitation occurs.

Open access

Xiaopeng Wei, Bin Wang, Qiang Zhang and Chao Che

Abstract

In recent years, there has been growing interesting in image encryption based on chaotic maps and wavelet transform. In this paper, a novel scheme for image encryption based on chaotic maps and reversible integer wavelet transform is proposed. Firstly, the cipher key which is related to plain-image is used to generate different parameters and initial values of chaotic maps. Then the plain-image is permuted by the order from chaotic maps, and processed by integer wavelet transform. A part of transform coefficient is diffused by the orbits of chaotic maps. Finally, the cipher image is obtained by inverse integer wavelet transform based on the diffused coefficient. Numerical experimental results and comparing with previous works show that the proposed scheme possesses higher security than previous works, which is suitable for protecting the image information.

Open access

Li-fei Sun, Qiang-qiang Wu, Zhi-hong Sun, Bing Han, Hong-feng Hao, Gui-chen Wang, Ming Li and Jin-biao Zhang

Abstract

Objective To observe the expression of inflammatory molecules in bone marrow immune cells of patients with immune-related hematocytopenia (IRH), and to investigate the immune mechanism and clinical significance of the disease.

Methods Total of 36 IRH patients were selected as observation group and 30 healthy people were taken as control group. Serum cytokines levels, activity of immunocytes and expression of HLA-DR were detected. Immune fluorescence was applied to observe the expression state of immunologic molecules and cytokines in IRH patients.

Results Serum cytokines were elevated in various degrees in observation group. Compared with the control group, the cytokines levels were significantly higher (P < 0.05). After treatement with immunosuppressive drugs, the serum levels of cytokines in observation group reduced to a level close to the control group. HLADR were upregulated in activated tissue basophils, eosinophils, dendritic cells (DC) and macrophages of bone marrow in IRH patients, and POX activity in these immunocytes of IRH was higher than that of the control group. Immune molecules were highly expressed in eosinophils, DC and macrophages.

Conclusions It is demonstrated that antibodies or self-reactive lymphocytes were produced in IRH marrow, which would cause lesions of hemocytes, and lead to pathological process finally. Structure of hematopoietic cells mutated and these cells might be acted as target cells of immunocytes in the pathological process. Immunocytes could secrete inflammatory factors and lead to immunologic injury of hemocyte.

Open access

Qiang Zhang, Haijian Wang and Tong Guo

Abstract

To study the influence of the random load on the V-lock chain ring for mining, the numerical simulation technology is used. The dynamic tension is obtained by using the dynamic model of the plough. The life and damage nephograms are obtained by using ANSYS Workbench. The analysis results show that the short fatigue life region of the V-lock chain ring for mining is mainly concentrated on the transition region between the medial straight edge and arc, and the fatigue damage of the link chain on the side of the motion direction of the plow head is larger than that on the other side. This link chain has strong anti-fatigue performance.

Open access

Su-zhen Jiang, Jia-jia Zheng, Xiang-Mei Chen, Ting Zhang, Qiang Xu, Hui Zhuang and Fengmin Lu

Abstract

Objective To identify the difference and significance of dominant types of hepatitis B virus (HBV) pre-S mutation between liver tumor tissues and paired adjacent non-tumor tissues and to test if the mutations were tumor tissue specific.

Methods HBV DNA isolated from 34 paired intratumoral and peritumoral tissues of hepatocellular carcinoma (HCC) patients were screened by PCR and direct sequencing. All patients carried HBV with genotype C, except for one B/C heterozygote. The expression, localization and excretion of LHBs mutant carrying pre-S deletions were characterized in vitro. The expression of endoplasmic reticulum (ER) GRP78 mRNA was assayed.

Results Four patterns of pre-S mutations were identified: pre-S1 in-frame deletion involving the first start codon; pre-S2 in-frame deletion; pre-S2 start codon mutation with or without in-frame deletion; and S promoter in-frame deletion (ΔSP). The first two types were evenly found in both tumor and non-tumor tissues. They were rarely present as dominant strains. The last two types were frequently found in the dominant strains in tumor tissues. The overall prevalence of HBV carrying ΔSP was 17.64% (6/34) in tumor tissues, but none were dominant in nontumor tissues. HBV carrying ΔSP was unable to produce S protein in vitro. Immunocytofluorescence assay showed that the ΔSP LHBs mutant aggregated in the cytoplasm, accumulating mainly in the ER. Transient transfection and expression of ΔSP mutant caused GRP78 up-regulation in vitro.

Conclusions HBV S promoter deletion was found dominantly in HCC tumor tissue. The aggregation of mutant large surface proteins in the ER possibly involved in HBV-related HCC.