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| 1 | A 3D GIS spatial data model based on conformal geometric algebra显示文摘We propose a new Geographic Information System (GIS) three-dimensional (3D) data model based on conformal geometric algebra (CGA). In this approach, geographic objects of different dimensions are mapped to the corresponding basic elements (blades) in Clifford algebra, and the expressions of multi-dimensional objects are unified without losing their geometric meaning. Geometric and topologic computations are also processed in a clear and coordinates-free way. Under the CGA framework, basic geometrics are constructed and expressed by the inner and outer operators. This expression combined geometrics of different dimensions and metric relations. We present the structure of the framework, data structure design, and the data storage, editing and updating mechanisms of the proposed 3D GIS data model. 3D GIS geometric and topological analyses are performed by CGA metric, geometric and topological operators using an object-oriented approach. Demonstrations with 3D residence district data suggest that our 3D data model expresses effectively geometric objects in different dimensions, which supports computation of both geometric and topological relations. The clear and effective expression and computation structure has the potential to support complex 3D GIS analysis, and spatio-temporal analysis. | YUAN LinWang YU ZhaoYuan LUO Wen ZHOU LiangChen LU GuoNia | 2011 | Science China Earth Sciences2011，54，1： | 26 |
| 2 | FEW-NNN: A Fuzzy Entropy Weighted Natural Nearest Neighbor Method for Flow-Based Network Traffic Attack Detection显示文摘Attacks such as APT usually hide communication data in massive legitimate network traffic, and mining structurally complex and latent relationships among flow-based network traffic to detect attacks has become the focus of many initiatives. Effectively analyzing massive network security data with high dimensions for suspicious flow diagnosis is a huge challenge. In addition, the uneven distribution of network traffic does not fully reflect the differences of class sample features, resulting in the low accuracy of attack detection. To solve these problems, a novel approach called the fuzzy entropy weighted natural nearest neighbor(FEW-NNN) method is proposed to enhance the accuracy and efficiency of flowbased network traffic attack detection. First, the FEW-NNN method uses the Fisher score and deep graph feature learning algorithm to remove unimportant features and reduce the data dimension. Then, according to the proposed natural nearest neighbor searching algorithm(NNN_Searching), the density of data points, each class center and the smallest enclosing sphere radius are determined correspondingly. Finally, a fuzzy entropy weighted KNN classification method based on affinity is proposed, which mainly includes the following three steps: 1、 the feature weights of samples are calculated based on fuzzy entropy values, 2、 the fuzzy memberships of samples are determined based on affinity among samples, and 3、 K-neighbors are selected according to the class-conditional weighted Euclidean distance, the fuzzy membership value of the testing sample is calculated based on the membership of k-neighbors, and then all testing samples are classified according to the fuzzy membership value of the samples belonging to each class;that is, the attack type is determined. The method has been applied to the problem of attack detection and validated based on the famous KDD99 and CICIDS-2017 datasets. From the experimental results shown in this paper, it is observed that the FEW-NNN method improves the accuracy and efficiency of flow-based network traffic attack detection. | Liangchen Chen Shu Gao Baoxu Liu Zhigang Lu Zhengwei Jiang | 2020 | China Communications2020，17，5： | 6 |
| 3 | CSES GNSS ionospheric inversion technique, validation and error analysis显示文摘With the increased number of low Earth orbit(LEO) satellites equipped with global navigation satellite system(GNSS) receiver,the LEO based GNSS slant total electron content(TEC) and electron density profile(EDP) data play an increasingly important role in space weather and ionospheric research due to improved global coverage. China Seismo-Electromagnetic Satellite(CSES), which was launched in February 2018, is equipped with GNSS receiver for either precise orbit determination(POD) and ionospheric inversion. The purpose of the present paper is to validate CSES GNSS ionospheric inversion technique based on the real observations and verify the accuracy of TEC and EDP retrieval based on the simulated data. The following conclusions can be drawn: the epoch difference inversion(EDI) derived from CSES can successfully retrieve the EDPs without non-occultation side measurements; the technique of EDI and the calibrated TEC inversion(CTI) have similar behaviors in inversion errors,however, the retrieved Nm F2 and hm F2 have a larger systematic error surrounding the equatorial ionization anomaly(EIA)where the assumption of spherical symmetry is often invalid; the precision and accuracy of retrieved TEC have been investigated in the paper based on the simulated data, and it is found that the accuracy of the retrieved TEC is relative to solar activity: the lower the F10.7 index, the higher the accuracy of retrieved TEC. | LIN Jian SHEN XuHui HU LiangChen WANG LanWei ZHU FuYing | 2018 | Science China(Technological Sciences)2018，61，5： | 5 |
| 4 | Geographic scenario:a possible foundation for further development of virtual geographic environments显示文摘It has been two decades since virtual geographic environments(VGEs)were initially proposed.While relevant theories and technologies are evolving,data organization models have always been the foundation of VGE development,and they require further exploration.Based on the comprehensive consideration of the characteristics of VGEs,geographic scene is proposed to organize geographic information and data.We empirically find that geographic scene provides a suitable organization schema to support geo-visualization,geo-simulation,and geo-collaboration.To systematically investigate the concept and method of geographic scene,Geographic Scenario is proposed as the theory on developing geographic scene,and corresponding key issues of the Geographic Scenario are illustrated in this article.Prospects of the proposed method are discussed with the hope of informing future studies of VGEs. | Guonian Lü Min Chen Linwang Yuan Liangchen Zhou Yongning Wen Mingguan Wu Bin Hu Zhaoyuan Yu Songshan Yue Yehua Sheng | 2018 | International Journal of Digital Earth2018，11，4： | 4 |
| 5 | Ionospheric disturbances associated with the 2015 M7.8 Nepal earthquake显示文摘Based on the total electron content(TEC) derived from Global Positioning System(GPS) observations of the Crustal Movement Observation Network of China(CMONOC) and the Global Ionosphere Map(GIM)from the Center for Orbit Determination in Europe(CODE),we detected and analyzed the ionospheric variations during the 2015 M7.8 Nepal earthquake(including the pre-earthquake ionospheric anomalies and coseismic ionospheric disturbances(CIDs) following the main shock).The analysis of vertical total electron content(VTEC) time series shows that the large-scale ionospheric anomalies appeared near the epicenter two days prior to the earthquake.Moreover,the pre-earthquake ionospheric anomalies were also observed in the geomagnetically conjugated region.In view of solar-terrestrial environment,the pre-earthquake ionospheric anomalies could be associated with the Nepal earthquake.In addition,we also detected the CIDs through the high-frequency GPS observation stations.The CIDs had obvious oscillated waveforms with the peak-to-peak disturbance amplitudes of about 1 TECu and 0.4 TECu,which propagated approximately with the horizontal velocities of 877 ± 75 m/s and 319 ± 30 m/s,respectively.The former is triggered directly by the acoustic waves which originated from the energy release of the earthquake near the epicenter,while the latter could be stimulated by the acoustic-gravity waves from the partial transformation of the acoustic waves. | Yiyan Zhou Jian Yang Fuying Zhu Fanfan Su Liangchen Hu Wenbo Zhai | 2017 | Geodesy and Geodynamics2017，8，4： | 4 |
| 6 | ABO blood group, hepatitis B viral infection and risk of pancreatic cancer显示文摘 | De‐ShenWang Dong‐LiangChen ChaoRen Zhi‐QiangWang Miao‐ZhenQiu Hui‐YanLuo Dong‐ShengZhang Feng‐HuaWang Yu‐HongLi Rui‐HuaXu | 2012 | Int J Cancer2012，，2： | 4 |
| 7 | Nowhere-zero 3-flows in Cayley graphs on generalized dihedral group and generalized quaternion group显示文摘Tutte 推测了那每张 4-edge-connected 图承认一没什么地方 -- 零 3 流动。在这份报纸,我们证明这推测是真的因为概括的二面的组和概括四元数上的 Cayley 图组织,它概括 F. 杨和 X. 李的结果[通知。过程。Lett, 2011, 111:416419 ] 。我们也概括 M 的早结果。N 桴? | Liangchen LI Xiangwen LI | 2015 | Frontiers of Mathematics in China2015，10，2： | 2 |
| 8 | High pressure effects on the crystal structure andelectric conductivity of perovskite like (Ca/Sr)_2CuO_2Cl_2 compounds显示文摘The crystal structure stability as well as electric conductance of (Sr/Ca)_2CuO_2Cl_2 compound with K_2NiF_4 structure was investigated up to 31 GPa using diamond anvil technique. It seems that (Sr/Ca)_2CuO_2Cl_2 is quite stable under pressure but with obvious anisotropic compressibility. The equation of state (EOS) obtained shows relative large bulk modulus. | LIU QingQing WANG FuRen LI FengYing CHEN LiangChen YU RiCheng JIN ChangQing LI YanChun LIU Jing | 2008 | Chinese Science Bulletin2008，53，18： | 2 |
| 9 | Genetic differentiation between populations of swimming crab Portunus trituberculatus along the coastal waters of the East China Sea显示文摘 | Yong Liu Ronglei Liu Liangchen Ye Jun Liang Fujun Xuan Qianghua Xu | 2009 | Hydrobiologia2009，，1： | 1 |
| 10 | A soft switching full bridge converter with reduced parasitic oscillation in a wide load range显示文摘 | ZHONG C SHASHA L LIANGCHEN S | 2014 | IEEE Transactions on Power Electronics2014，29，2： | 1 |
| 11 | Glucose-sensitive aggregates formed by poly (ethylene oxide)-block- poly(2-glucosyl-oxyethyl acrylate) with coneanavalin a in dilute aqueous medium显示文摘 | You Liangchen Lu Fengzhu Li Zichen | 2003 | Macromolecules2003，36，： | 1 |
| 12 | Improving the wind environ -ment in high -density cities by understanding urban morphology and surface roughness:A study in Hong Kong显示文摘 | Edward N g ChaoYuan LiangChen | 2011 | Landscape and Urban Planning 20112011，5974，： | 1 |
| 13 | A soft switching full bridge converter with reduced parasitic oscillation in a wide load range显示文摘 | Chen Zhong Liu Shasha Shi Liangchen | 2014 | IEEE Transactions on Power Electronics2014，29，2： | 1 |
| 14 | Comparative study of regulatory T cells expanded ex vivo from cord blood and adult peripheral blood显示文摘 | HuahuaFan JieYang JunHao YanaRen LiangChen GuipingLi RufengXie YimingYang FengGao MingyaoLiu | 2012 | Immunology2012，，2： | 1 |
| 15 | Global existence and boundedness of classical solutions to a parabolic-parabolic chemotaxis system显示文摘 | Mu Chunlai Wang Liangchen Zheng Pan | 2013 | Nonlinear Anal Real World Appl2013，14，3： | 1 |
| 16 | Environmentally friendly wood adhesive from a renewable plant polymer: characteristics and optimization显示文摘 | Syed H Imam SheraldHGordon LijunMaol LiangChen | 2001 | Polymer Degradation and Stability2001，，73： | 1 |
| 17 | Hyperbaric oxygen therapy ameliorates the blood–retinal barrier breakdown in diabetic retinopathy显示文摘 | Yun‐HsiangChang Po‐LiangChen Ming‐ChengTai Chiao‐HongChen Da‐WenLu Jiann‐TorngChen | 2006 | Clinical & Experimental Ophthalmology2006，，6： | 1 |
| 18 | Extraction of ocean tidal information based on global equal-area grid and satellite altimeter data显示文摘Harmonic analysis of satellite altimetry data based on a global regular grid is affected by the grid spatial tessellation and placement of the grids.With the increase of latitude,the traditional lat/lon grid deforms greatly,resulting in uneven distribution of satellite altimeter data with latitude,which affects the extraction of tidal information.Alternatively,Hexagonal grids have been proved to be advantageous due to their isotropic,uniform neighbourhood,equal-area and more.Considering the merits above,the purpose of this paper is to use the global equal-area hexagonal grid to conduct a harmonic analysis of satellite altimeter data.First,the Icosahedron Snyder Equal Area projection method is used to construct a global equal-area hexagonal grid,Then the time series data of 19.8 years of Jason series satellite altimeter data are obtained.Finally,the harmonic constants of eight constituents(the M2,S2,N2,K2,K1,O1,P1,Q1)are extracted by harmonic analysis.By analysing the results,we conclude that the harmonic constants extracted from the global equal-area hexagonal grid have considerable accuracy and are consistent with the tidal characteristics of the eight components.Meanwhile,the accuracy of harmonic constants extracted from equal-area hexagonal grids is better than that of lat/lon grids. | Wenbo Wang Huijun Zhou Senyuan Zheng Guonian Lü Liangchen Zhou | 2022 | International Journal of Digital Earth2022，15，1： | 0 |
| 19 | Global Dynamics of a Quasilinear Chemotaxis System with Indirect Signal Production and Generalized Logistic Source显示文摘This paper considers the following quasilinear chemo-taxis system with indirect signal production and generalized logistic source{u_(t)=▽·(▽(u)▽u)-▽·(S(u)▽v)+μ(u-u^(Y)),x∈Ω,t>0 O=△v-v+w,x∈Ω,t>0 w_(t)=-δw+u,x∈Ω,t>0 under homogeneous Neumann boundary conditions in a smooth bounded domainΩ■R^(n)(n≥1),where the parametersμ,δ>0 andγ>1,the functions D(u)and S(u)are supposed to be smooth fulfilling D(u)≥C_(D)(u+1)^(-a)and S(u)≤C_(S)u(u+1)^(β-1)for all u≥0 with C D,α,β∈R and.It is proved that the corresponding initial-boundary value problem possesses a global bounded classical solution ifα+2β<γ-1.Moreover,ifμis suitably large,the asymptotic behavior and convergence rates are also been considered. | YE Xiaobing WANG Liangchen | 2021 | Wuhan University Journal of Natural Sciences2021，26，5： | 0 |
| 20 | Structural Phase Transitions of Iodine at High Pressure显示文摘The compression and polymorphic phase transitions of iodine have been studied by using x-ray diffraction with a diamond anvil cell at high pressure up to 77GPa.Considering that iodine is reactive with iron in air,a corrosion-resisting and high-strength gasket was put between the diamonds,thus the sample can be mounted at atmospheric pressure and room temperature.Pressure was measured in terms of the ruby fluorescence and the molybdenum diffraction as an internal pressure standard.According to the x-ray diffraction results,the iodine undergoes the following three structural phase transitions with pressure increasing:(1)At 21 GPa,from base centred orthorhombic phase(phase Ⅰ)to body centred orthorhombic phase(phase Ⅱ).A 2%change in volume occurs.(2)At 44 GPa,from phase II to body centred tetragonal phase(phase Ⅲ).This is a second order phase transition.(3)At 71 GPa,from phase III to fcc phase(phase Ⅳ).The volume decreases by 3%.At this time,the volume is 45%of the original one at atmospheric pressure. | CHEN Liangchen ZHANG Zhiting CHE Rongzheng YU Tingnan WANG Jifang | 1994 | Chinese Physics Letters1994，11，2： | 0 |
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