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Search Results: 1 - 10 of 104228 matches for " Zhang Lingjuan "
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A 3D Target Imaging Algorithm Based on Two-Pass Circular SAR Observations
Lingjuan Yu;Yunhua Zhang
PIER , 2012, DOI: 10.2528/PIER11101901
Abstract: In circular synthetic aperture radar (CSAR), the radar collects data over a circular not a linear trajectory. The two-dimensional (2D) CSAR image also contains three-dimensional (3D) information about the target. In this paper, we propose an imaging algorithm for 3D target reconstruction with two-pass CSAR observations so as to overcome the problem of limited azimuthal persistence for real anisotropic targets, and avoid the assumption that target falls into the same resolution cell for each elevation pass when multi-pass observations are used. In the algorithm, the first step is to divide both of the two full-aperture CSAR data into subapertures in the same way; the second step is to obtain, for each subaperture, the height of target according to the established relationship between the pixel displacements in the image pair of two observations on the same focal plane and the pixel displacements in the image pair of one observation on two different focal planes; the third step is to obtain the 3D target coordinates based on the retrieved height information and the 2D image coordinates; the last step is to get the final 3D image by combining the obtained 3D images of all subapertures. The results of point target simulation indicate that the 3D information (both amplitudes and positions) are well reconstructed. At the same time, the processing results of backhoe data simulated by the Xpatch software show that the outline of the 3D structure is also well reconstructed although the available data corresponding to the depressing angles are not as good as expected.
Application of the Fractional Fourier Transform to Moving Train Imaging
Lingjuan Yu;Yunhua Zhang
PIER M , 2011, DOI: 10.2528/PIERM11051401
Abstract: This paper introduces an imaging algorithm with application of fractional Fourier transform (FrFT) for ground moving train imaging by Ku-band ground-based radar. In view of the fact that the train speed is varying when acrossing the radar beam, the multiple Doppler parameters are estimated corresponding to different range positions, i.e., they are estimated from different sections of data in FrFT domain, then the train is imaged section by section, and finally these sectional images are combined to get the full image of the train. Because traditional parameter estimation method by two-dimensionally searching the peaks in FrFT domain is inefficient, we transfer the parameter searching problem into an one-dimensional optimization problem, which can be solved with high efficiency by using the golden section searching method.
Random Step Frequency Csar Imaging Based on Compressive Sensing
Lingjuan Yu;Yunhua Zhang
PIER C , 2012, DOI: 10.2528/PIERC12061509
Abstract: Circular synthetic aperture radar (CSAR) imaging based on compressive sensing with random step frequency (RSF) as transmitted signal is introduced. CSAR is capable of obtaining both two-dimensional high resolution image and three-dimensional image due to a circular collection trajectory. RSF signal shares good characteristics of noise signals including ``thumbtack-shape" ambiguity function, low probability of interception, and strong anti-jamming capability. As a result, CSAR adopting RSF signal can make use of advantages of both CSAR and RSF signal. Compressive sensing is a new data acquisition and reconstruction theorem for sparse or compressible signals, which needs fewer samples to reconstruct signals than traditional Nyquist theorem. Simulation results show that both two-dimensional and three-dimensional targets can be well reconstructed from few samples by applying compressive sensing to RSF CSAR imaging.
Csar Imaging with Data Extrapolation and Approximate Glrt Techniques
Lingjuan Yu;Yunhua Zhang
PIER M , 2011, DOI: 10.2528/PIERM11062904
Abstract: Circular synthetic aperture radar (CSAR) is different from other usual SAR modes, e.g., Stripmap SAR or Spotlight SAR, which takes a circular path rather than a straight path. It can provide not only two-dimensional (2-D) high resolution images but also three-dimensional (3-D) information about the target. In this paper, 2-D CSAR imaging containing 3-D information about the target is discussed. Considering the limited bandwidth of radar system and the limited angular persistence of the reflector's scattering characteristic in a real scene, we combine the data extrapolation technique based on the autoregressive (AR) model with the non-coherent combination of the sub-aperture images based on the approximate Generalized Likelihood Ratio Test (GLRT) technique to get a 2-D CSAR image with resolution improved and with aspect-dependent reflectivity characteristics kept. The GTRI T-72 tank dataset is processed to test the algorithm.
The Relationship between Employee Psychological Capital and Change-Supportive Behavior—Mediating Effect of Cognitive of Change  [PDF]
Lingjuan Wang
Open Journal of Social Sciences (JSS) , 2015, DOI: 10.4236/jss.2015.34015
Abstract: For the transition period of Chinese enterprises, change has become an important part of corporate life, and employees’ support for change is the key to successful business change. Psychological capital, as a core positive psychological element of employee, plays an important role in organizational change. Drawing upon the existing literature and using a sample of employees, this study investigated the relationship of employee psychological capital, cognitive of change, and change-supportive behavior. Results revealed that employee psychological capital was positively related to change-supportive behavior, with this relationship mediated by cognitive of change.
A meta Analysis of Gemcitabine plus Platinum Chemotherapy Compared with Single-agent Chemotherapy in the Treatment of Non-small Cell Lung Cancer
Yunjiu GOU,Lingjuan ZHANG,Qimei YANG,Rongfang ZHANG
Chinese Journal of Lung Cancer , 2010,
Abstract: Background and objective Whether gemcitabine plus platinum chemotherapy is superior to gemcitabine or platinum single-agent chemotherapy for patients with non-small cell lung cancer (NSCLC) is still in dispute, and the aim of this study is to evaluate the efficacy and safety of gemcitabine combining platinum chemotherapy for patients with NSCLC. Methods We searched relevant randomized controlled trials (RCTs) from VIP, CBM, CNKI, the Cochrane library, PUBMED and EMBASE. We traced the related references and experts in this field and communicated with other authors to obtain the information that has not been found. We made quality assessment of qualified RCTs assessed by the exclusion and inclusion criteria and used RevMan 5.0 provided by the Cochrane Collaboration to perform meta-analysis. Results Four RCTs were eligible and included 984 patients. Meta analysis results suggested that: compared with gecitabine single-agent chemotherapy, the combination had a statistically significant benefit in increasing the response rate (OR=3.29, 95%CI: 1.79-6.05, P=0.000 1) and 2-year survival rate (OR=3.22, 95%CI: 1.45-7.12, P=0.004) while increased the risk of the incidence of adverse reactions, especially the grade 3-4 thrombocytopenia (RR=8.16, 95%CI: 1.71-39.07, P=0.009); compared with cisplatin single-agent chemotherapy, the combination had a statistically significant benefit in increasing the response rate (OR=3.51, 95%CI: 2.20-5.60, P<0.01) and 1-year survival rate (OR=1.67, 95%CI: 1.16-2.41, P=0.006) while increased the risk of the incidence of adverse reactions, especially the grade 3-4 thrombocytopenia (OR=28.55, 95%CI: 14.06-57.04, P<0.01). Conclusion Compared with single-agent chemotherapy, the combining can significantly improve the efficiency and survival rate while increase the toxicity rare. The results still need to be proved by high quality RCTs.
A Systematic Review of Erlotinib for Advanced Non-small Cell Lung Cancer
Huiling GUO,Rongfang ZHANG,Qimei YANG,Lingjuan ZHANG
Chinese Journal of Lung Cancer , 2009,
Abstract: Background and objective It was unclear whether advanced non-small cell lung cancer (NSCLC) patients could benefit from erlotinib therapy. This study was aimed to evaluate the efficacy and safety of NSCLC patients treated with erlotinib. Methods The relevant randomized controlled trials (RCT) were searched from VIP, CMB, CNKI, PubMed, EMBASE and The Cochrane Library. The related references and experts in this field were traced, and other authors were communicated with to obtain the information that has not been found. Quality assessment of qualified RCTs assessed by the exclusion and inclusion criteria and RevMan 5.0 provided by the Cochrane Collaboration was used to perform meta-analysis. Results Three RCTs involving 2 969 patients were included. Meta analysis results suggested that erlotinib was superior to placebo for one year survival rate (OR=1.18, 95%CI: 1.01-1.38), tumor response rate (OR=1.24, 95%CI: 1.03-1.49), median overall survival, median progression-free survival and tumor responses duration. At the same time, the incidence of grade 3-4 skin rash (OR=16.33, 95%CI: 7.01-38.02) and diarrhea (OR=5.02, 95%CI: 2.93-8.60) of the adverse reactions was increased. Conclusion Advanced non-small cell lung cancer patients could benefit from Erlotinib therapy, but the incidence of skin rash and diarrhea was significantly increased, and in the absence of damage to the blood system, serious liver and kidney damage, cardiac toxicity, etc, there were no difference with placebo.
Estimate on the Dimension of Global Attractor for Nonlinear Higher-Order Coupled Kirchhoff Type Equations  [PDF]
Guoguang Lin, Lingjuan Hu
Advances in Pure Mathematics (APM) , 2018, DOI: 10.4236/apm.2018.81002
Abstract: In this paper, we investigate the finite dimensions of the global attractor for nonlinear higher-order coupled Kirchhoff type equations with strong linear damping in Hilbert spaces E0?and E1. Under the appropriate assumptions, we acquire a precise estimate of the upper bound for its Hausdorff and Fractal dimensions.
The Inertial Manifold for a Class of Nonlinear Higher-Order Coupled Kirchhoff Equations with Strong Linear Damping  [PDF]
Guoguang Lin, Lingjuan Hu
International Journal of Modern Nonlinear Theory and Application (IJMNTA) , 2018, DOI: 10.4236/ijmnta.2018.72003
Abstract: This paper considers the long-time behavior for a system of coupled wave equations of higher-order Kirchhoff type with strong damping terms. Using the Hadamard graph transformation method, we obtain the existence of the inertial manifold while such equations satisfy the spectral interval condition.
Widely Tunable Sampled-Grating DBR Laser
Kan Qiang,Zhao Lingjuan,Zhang Jing,Zhou Fan,Wang Baojun,Wang Lufeng,and Wang Wei
半导体学报 , 2005,
Abstract: The 3-section SG-DBR tunable laser is fabricated using an ion implantation quantum-well intermixing process.The over 30nm discontinuous tuning range is achieved with the SMRS greater than 30dB.
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