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Chinese Journal of Electronics 2019年第6期28卷 1184-1190页

作者： JIA Xu SUN Fuming LI Haojie CAO Yudong School of Electronics and Information Engineering Liaoning University of Technology School of Software Technology Dalian University of Technology

Most of the existed vein features are lack of robustness to light intensity variation, and some algorithms rely on the specified vein data sets, which leads to the limitation of real applications. To solve the problems,we propose a novel vein recognition algorithm based on Nonnegative matrix factorization(NMF) with double regularization terms. The innovations of our algorithm are mainly reflected in the following two aspects: in order to improve feature robustness, a novel feature mapping function is designed to map the initial Histogram of oriented gradient(HOG) feature to a new space; to enhance the recognition performance, an effective NMF model is presented, which not only reduces feature dimension, but also optimizes the feature sparsity and clustering property simultaneously. Experiments show that the proposed algorithm can achieve satisfactory results in terms of False rejection rate(FRR) and False acceptance rate(FAR), which indicates that our algorithm is valuable for other classification problems.

关键词： Vein recognition Nonnegative matrix factorization(NMF) mapping function Feature sparsity

An initial investigation of the non-isotropic feature of GNSS tropospheric delay

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Satellite Navigation 2024年第1期5卷 155-167页

作者： Ying Xu Zaozao Yang Hongzhan Zhou Fangzhao Zhang College of Geodesy and Geomatics Shandong University of Science and Technology579 Qianwangang RoadQingdao266590ShandongChina

Tropospheric delay is a significant error source in Global Navigation Satellite Systems(GNSS)*** Path Delay(SPD)is commonly derived by multiplying Zenith Tropospheric Delay(ZTD)with a mapping ***,mapping functions,assuming atmospheric isotropy,restrict the accuracy of derived *** improve the accuracy,a horizontal gradient correction is introduced to account for azimuth-dependent SPD variations,treating the atmosphere as *** study uncovers that,amidst atmospheric dynamics and spatiotemporal changes in moisture content,the SPD deviates from that based on traditional isotropy or anisotropy *** innovatively introduces the concept that SPD exhibits non-isotropy with respect to azimuth *** validation involves assessing SPD accuracy using three mapping functions at five International GNSS Service(IGS)stations,referencing the SPD with the ray-tracing *** subsequently evaluates the SPD accuracy with horizontal gradient correction based on Vienna mapping function 3(VMF3)***,the non-isotropic of SPD is analyzed through the ray-tracing *** results indicate the smallest residual(1.1–82.7 mm)between the SPDs with VMF3 and those with the ***,introducing horizontal gradient correction yields no significant improvement of SPD *** potential decimeter-level differences in SPD due to non-isotropic tropospheric delay across azimuth angles,a precise grasp and summary of these variations is pivotal for accurate tropospheric delay *** finding provides vital support for future high-precision tropospheric delay modeling.

关键词： Tropospheric delay GNSS Non-isotropy mapping function Ray-tracing Horizontal gradient ERA5

New Finite Difference Mapped WENO Schemes with Increasingly High Order of Accuracy

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Communications on Applied Mathematics and Computation 2023年第1期5卷 64-96页

作者： Jun Zhu Jianxian Qiu College of Science Nanjing University of Aeronautics and AstronauticsNanjing 210016JiangsuChina School of Mathematical Sciences and Fujian Provincial Key Laboratory of Mathematical Modeling and High-Performance Scientific Computing Xiamen UniversityXiamen 361005FujianChina

In this paper,a new type of finite difference mapped weighted essentially non-oscillatory(MWENO)schemes with unequal-sized stencils,such as the seventh-order and ninthorder versions,is constructed for solving hyperbolic conservation *** the purpose of designing increasingly high-order finite difference WENO schemes,the equal-sized stencils are becoming more and more *** more we use wider candidate stencils,the bigger the probability of discontinuities lies in all ***,one innovation of these new WENO schemes is to introduce a new splitting stencil methodology to divide some fourpoint or five-point stencils into several smaller three-point *** the usage of this new methodology in high-order spatial reconstruction procedure,we get different degree polynomials defined on these unequal-sized stencils,and calculate the linear weights,smoothness indicators,and nonlinear weights as specified in Jiang and Shu(***.126:202228,1996).Since the difference between the nonlinear weights and the linear weights is too big to keep the optimal order of accuracy in smooth regions,another crucial innovation is to present the new mapping functions which are used to obtain the mapped nonlinear weights and decrease the difference quantity between the mapped nonlinear weights and the linear weights,so as to keep the optimal order of accuracy in smooth *** new MWENO schemes can also be applied to compute some extreme examples,such as the double rarefaction wave problem,the Sedov blast wave problem,and the Leblanc problem with a normal CFL *** numerical results are provided to illustrate the good performance of the new finite difference MWENO schemes.

关键词： Finite difference Mapped WENO scheme mapping function Mapped nonlinear weight Unequal-sized stencil Extreme example

On ionosphere-delay processing methods for single-frequency precise-point positioning

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Geodesy and Geodynamics 2011年第1期2卷 71-76页

作者： Tu Rui Zhang Qin Huang Guanwen Zhao Hong College of Geology Engineering and Geomatics Chang＇an University Xi＇an 710054 China

In single-frequency precise-point positioning of a satellite,ionosphere delay is one of the most important factors impacting the accuracy. Because of the instability of the ionosphere and uncertainty of its physical properties, the positioning accuracy is seriously limited when using a precision-limited model for correction. In order to reduce the error, we propose to introduce some ionosphere parameter for real-time ionosphere-delay estimation by applying various mapping functions. Through calculation with data from the IGS（ International GPS Service） tracking station and comparison among results of using several different models and mapping functions, the feasibility and effectiveness of the new method are verified.

关键词： single-frequency precise-point positioning ionosphere delay model correction mapping function parameter estimation

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PATTERN mapping ON BETA-SPLINE SURFACES——BILINEAR mapping METHOD

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Computer Aided Drafting,Design and Manufacturing 1992年第2期3卷 27-31页

作者： Zhang Mandong Zhao Hongsheng Guan Rongchang Taiyuan University of Technology Taiyuan 030024, P. R. China

Texture pattern mapping is one of the most important techniques for high quality image syn- thesis. It can largely enhance the visual richness of raster-scan images. In this paper is presented a new method of mapping planar texture pattern onto beta-spline curved surfaces——bilinear mapping method which can map planar texture pattern onto curved surfaces with less distortion, and also can fulfill the geometric transformation of the texture pattern on the curved surfaces by operating the pattern win- dow. It is valuable to both CAD/CAM in artistic field and computer graphics.

关键词： texture pattern mapping mapping function Beta-spline bilinear mapping

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Vertical deformation of the fault-crossing network around Baotou,observed by GPS

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Geodesy and Geodynamics 2013年第4期4卷 57-61页

作者： Qin Shanlan Du Weiji Ji Lingyun Second Crust Monitoring and Application Center China Earthquake Administration Nanjing Institute of Surveying Mapping & Geotechnical InvestigationCo.Ltd

GPS data and precise leveling data of seismic network profiles across the fault in Baotou in 2006, 2009 and 2011 were processed and analyzed to test the feasibility of using GPS technology for fault-crossing vertical deformation monitoring. The results showed that high precision cross-fauh vertical deformation measurements can be obtained using appropriate GPS data processing strategies.

关键词： fault-crossing precise leveling vertical deformation GPS vertical deviation mapping function

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