Reduced-Dynamic Precise Orbit Determination for Low Earth Orbiters Based on Helmert Transformation
A model based on Helmert transformation is presented in reduced-dynamic Precise Orbit Determination(POD). As an implementation, a reduced-dynamic POD approach was developed. The approach includes two steps: firstly, kinematic POD and then reduced-dynamic POD. Based on the approach, a set of programs were developed. POD of CHAMP and GRACE was then carried out. Kinematic and reduced-dynamic POD for CHAMP and GRACE satellite over 2 weeks time show that reduced-dynamic orbits of CHAMP have a mean 3D RMS of 0.26 m compared to PSO orbit of GFZ, and the mean 3D RMS of GRACE-A has the same value compared to GNV1B orbit of JPL. The 3D RMS is reduced by up to 40% compared to kinematic solutions.
Large scaled projects are conducted in South Yellow Sea in recent years. Topographic effect and tidal current are key issues to the coastal engineering and the ocean engineering. In this study, field surveys were conducted to investigate the tidal level, current velocity, and current direction in South Yellow Sea. A numerical model was developed to simulate the radial current field based on the field data. To investigate the mechanism of the radial current field, the actual topography and a smoothed topography were applied in the numerical model, respectively. Results show that, the current field appeares radial because of the tidal system rather than the submarine topography. Local topography centralized the radiation centre and shifted the high-velocity zones. The actual topographic effect is proposed, and results show that local topography increases the flood tide velocity and decreases the ebb tide velocity. Lagrangian residual currents are calculated to illustrate possible sediment sources and transport routes.
Fault tolerant control of switched nonlinear systems with time delay under asynchronous switching
This paper investigates the problem of fault tolerant control of a class of uncertain switched nonlinear systems with time delay under asynchronous switching. The systems under consideration suffer from delayed switchings of the controller. First, a fault tolerant controller is proposed to guarantee exponentially stability of the switched systems with time delay. The dwell time approach is utilized for stability analysis and controller design. Then the proposed approach is extended to take into account switched time delay systems with Lipschitz nonlinearities and structured uncertainties. Finally, a numerical example is given to illustrate the effectiveness of the proposed method.
Jiangeng Han, Xin Wang, Zheng Chen, Ning Gao and Chen Wang
Patients with diabetes are prone to concurrent infection. The mechanism of concurrent infection is related to factors such as hyperglycemia and weakened defense function. The infections of patients with diabetes include general and special infections. General infection includes infections in the respiratory system, urinary system, hepatobiliary system, and skin mucosa. Meanwhile, special infection includes invasive otitis externa, nasal mucormycosis, necrotizing fasciitis, and emphysema infection. Patients with special infections also have a higher mortality rate than those with general ones. Complicated infection with diabetes is difficult to treat and has poor prognosis. Therefore, a patient requires active treatment once infected with this infection.
Guo Yanhua, Zhou Sihua, Zhou Xiaodong, Chen Bojun and Wang Shaohui
Defect Detection is one of the most important parts of Automatic Identification and Data transmission. Quick Response code (QRcode) is one of the most popular types of two-dimensional barcodes. It isachallenge to detect defect of various QRcode images efficiently and accurately. In this paper, we propose the procedure byaserial of carefully designed preprocessing methods. The defect detection procedure consists of QRcode identification, QRcode reconstruction, perspective transformation, image binarization, morphological operation, image matching, and Blob analysis. By these steps, we can detect defect of different types of QRcode images. The experiment results show that our method has stronger robustness and higher efficiency. Moreover, experiment results on QRcode images show that the prediction accuracy of proposed method reaches 99.07%with an average execution time of 6.592 ms. This method can detect defect of these images in real time.
Huangyuan Li, Siying Wu, Junnian Chen, Bo Wang and Nian Shi
Transcription factor NF-E2-related factor 2 (Nrf2) is important for cell protection against chemical-induced oxidative stress. Previously, we have reported that in PC12 cells, Nrf2 can be triggered by deltamethrin (DM), a commonly used pyrethroid insecticide. Molecular mechanisms behind Nrf2 activation by DM are still unclear. Here we studied the effects of cell glutathione (GSH) depletion on Nrf2 activation by DM. We found that DM enhanced Nrf2 expression at the mRNA and protein levels and increased nuclear Nrf2 levels. Activation of Nrf2 was associated with activation of its downstream targets, such as heme oxygenase-1 (HO-1) and glutamate cysteine ligase catalytic subunit (GCLC). In contrast, DL-buthionine-[S,R]- sulfoximine (BSO), a known GSH-depleting agent, did not increase Nrf2 protein expression or cause its nuclear accumulation. However, pre-treatment with BSO triggered mRNA expression of HO-1 and GCLC. Furthermore, BSO pre-treatment suppressed DM-induced Nrf2 upregulation and activation and lowered mRNA expression of HO-1 and GCLC upon DM treatment. These data demonstrate that GSH depletion is not necessary for the activation of Nrf2/ARE by DM in PC12 cells, and that GCLC and HO-1 expression can increase through other signalling pathways.
The adjacency matrix of a graph is a matrix which represents adjacent relation between the vertices of the graph. Its minimum eigenvalue is defined as the least eigenvalue of the graph. Let Gn be the set of the graphs of order n, whose complements are connected and have pendent paths. This paper investigates the least eigenvalue of the graphs and characterizes the unique graph which has the minimum least eigenvalue in Gn.