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chinese Science Bulletin 2002年第10期47卷 863-867页

作者： LIU Rui & WEI FengsiDepartment of Geophysics, Peking University, beijing 100871, china Lab for Space Weather, Center for Space Science and applied Research, {3. academy of Sciences, beijing 100080, china Department of Geophysics Peking University Beijing China Lab for Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China

A statistical study of magnetic fluctuations near the front boundaries of magnetic clouds is approached with the method of Minimum Variance Analysis, based on the data of ImpS and Wind spacecraft. New discoveries are that (1) fluctuation anisotropy tends to increase across the front boundaries of magnetic clouds; (2) there is a good correlation between the fluctuation anisotropy and the geomagnetic activity indices; and (3. in some cases, although there is southward field component immediately after the front boundary, Kp index descends (or Dst index ascends) with a corresponding decrease of the fluctuation anisotropy; in other cases with no distinct southward field component, Kp index ascends (or Dst index descends) with a corresponding increase of the fluctuation anisotropy. Thus we suggest that the fluctuation anisotropy might be a useful indicator in diagnosing the magnetic activities of magnetic clouds.

关键词： front boundary of magnetic clouds geomagnetic activity fluctuation anisotropy.

A shortest path algorithm for moving objects in spatial network databases

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Progress in Natural Science:Materials International 2008年第7期18卷 893-899页

作者： Xiaolan Yin a,b,*, Zhiming Ding c, Jing Li a a Technology Center of Software Engineering, Institute of Software, chinese academy of Science, P.O. Box 8718, beijing 100080,{3. b Graduate University, chinese academy of Sciences, beijing 100049,{3. c Technology Center of Basic Software, Institute of Software, chinese academy of Sciences, beijing 100080,{3. Technology Center of Software Engineering Institute of Software Chinese Academy of Science P.O. Box 8718 Beijing 100080 China Graduate University Chinese Academy of Sciences Beijing 100049 China Technology Center of Basic Software Institute of Software Chinese Academy of Sciences Beijing 100080 China

One of the most important kinds of queries in Spatial Network Databases (SNDB) to support location-based services (LBS) is the shortest path query. Given an object in a network, e.g. a location of a car on a road network, and a set of objects of interests, e.g. hotels, gas station, and car, the shortest path query returns the shortest path from the query object to interested objects. The studies of shortest path query have two kinds of ways, online processing and preprocessing. The studies of preprocessing suppose that the interest objects are static. This paper proposes a shortest path algorithm with a set of index structures to support the situation of moving objects. This algorithm can transform a dynamic problem to a static problem. In this paper we focus on road networks. However, our algorithms do not use any domain specific information, and therefore can be applied to any network. This algorithm’s complexity is O(klog2i), and traditional Dijkstra’s complexity is O((i + k)2).

关键词： Moving object Spatial network databases Shortest path index Shortest path

ON THE EXISTENCE OF SOLUTIONS TO A TYPE OF NONLINEAR DIFFERENTIAL-ITERATIVE EQUATIONS

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chinese Annals of mathematics,Series B 2000年第2期21卷 217-224页

作者： GE WEIGAO(Department of applied mathematics, beijing Institute of Technology, beijing 100081, china.) LI CUIZHE(Department of applied mathematics, beijing Institute of Technology, beijing 100081, china.) YU YUANHONG(Inditute of applied mathematics, Acad Department of applied mathematics Beijing Institute of Technology Beijing 100081 China Institute of applied mathematics Academia Sinica Beijing 100080 China

Under the assumption that h(z) is strictly monotone the existence of solutions to a type of nonlinear differential-iterative equations in the form of x’(t) = g(x(t)) -h(x(x(t))) is discussed according to the behavior... 详细信息

关键词： Differential-iterative equation Quasi-isoclinic curve Fixed point

A Series of Soliton-like and Double-like Periodic Solutions of a (2+1)-Dimensional Asymmetric Nizhnik-Novikov-Vesselov Equation

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Communications in Theoretical Physics 2004年第11期42卷 655-660页

作者： CHEN Yong,~(1,3.4, WANG Qi~(2,4) LI Biao~(2,4) ~1Department of mathematics,Ningbo University,Ningbo 3.5211,china ~2Department of applied mathematics,Dalian University of Technology,Dalian 116024,china ~3.epartment of Physics,Shanghai Jiao Tong University,Shanghai 20003.,china ~4Key Laboratory of mathematics Mechanization~ the chinese academy of Sciences,beijing 100080,china Key Laboratory of mathematics Mechanization the Chinese Academy of Sciences Beijing 100080 China

We generalize the algebraic method presented by Fan [***.A:***.3. (2003. 7009)] to uniformlyconstruct a series of soliton-like solutions and double-llke periodic solutions for nonlinear partial differential equations(NPDE),As an application of the method,we choose a (2+1)-dimensional asymmetric Nizhnik-Novikov-Vesselov equa-tion and successfully construct new and more general solutions including a series of nontraveling wave and coefficientfunctions’ soliton-like solutions,double-like periodic and trigonometric-like function solutions.

关键词： symbolic computation soliton-like solution Weierstrass and Jacobi elliptic functions periodic solution

Recommendation Method for Contrastive Enhancement of Neighborhood Information

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Computers, Materials & Continua 2024年第1期78卷 453-472页

作者： Hairong Wang beijing Zhou Lisi Zhang He Ma School of Computer Science and Engineering North Minzu UniversityNingxia750021China

Knowledge graph can assist in improving recommendation performance and is widely applied in various person-alized recommendation ***,existing knowledge-aware recommendation methods face challenges such as weak user-item interaction supervisory signals and noise in the knowledge *** tackle these issues,this paper proposes a neighbor information contrast-enhanced recommendation method by adding subtle noise to construct contrast views and employing contrastive learning to strengthen supervisory signals and reduce knowledge ***,first,this paper adopts heterogeneous propagation and knowledge-aware attention networks to obtain multi-order neighbor embedding of users and items,mining the high-order neighbor informa-tion of users and ***,in the neighbor information,this paper introduces weak noise following a uniform distribution to construct neighbor contrast views,effectively reducing the time overhead of view *** paper then performs contrastive learning between neighbor views to promote the uniformity of view information,adjusting the neighbor structure,and achieving the goal of reducing the knowledge noise in the knowledge ***,this paper introduces multi-task learning to mitigate the problem of weak supervisory *** validate the effectiveness of our method,experiments are conducted on theMovieLens-1M,MovieLens-20M,Book-Crossing,and Last-FM *** results showthat compared to the best baselines,our method shows significant improvements in AUC and F1.

关键词： Contrastive learning knowledge graph recommendation method

L^1-uniqueness of Sturm-Liouville operators

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Science china mathematics 2010年第1期53卷 173-178页

作者： WU LiMing1,2, YAO Nian3.& ZHANG ZhengLiang3.Laboratoire de Mathématiques Appliquées, CNRS-UMR 6620, Université Blaise Pascal, 63.77 Aubière, France 2Institute of applied mathematics, chinese {3. of Sciences, beijing 100190, china 3.epartment of mathematics, Wuhan University, Wuhan 43.072, china 1. Laboratoire de Mathématiques Appliquées CNRS-UMR 6620 Université Blaise Pascal 63177 Aubière France2. Institute of Applied Mathematics Chinese Academy of Sciences Beijing 100190 China3. Department of Mathematics Wuhan University Wuhan 430072 China

In this paper, we give two sufficient and necessary conditions for the L1-uniqueness of one-dimensional Sturm-Liouville operator Lf = af″ + bf′- V f, f∈D = C 0 ∞ (I), where I is an open interval of R and V≥0.

关键词： Sturm-Liouville operators L1-uniqueness

REMARK ON UNIQUE CONTINUATION OF SOLUTIONS TO THE STOKES AND THE NAVIER-STOKES EQUATIONS

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Acta Mathematica Scientia 2005年第4期25卷 594-598页

作者： Jin Kim Tu 常谦顺 TuInstitute of mathematics Academy of Sciences of DPR of Korea Pyonyang DPR of Korea Institute of applied mathematics Academy of Mathematics and System SciencesChinese Academy of Sciences Beijing 100080 China

New simple proofs of unique continuation of solutions for the Stokes equation and Navier-Stokes equations is presented under weaker conditions.

关键词： Stokes equation Navier-Stokes equation

BRST quantization and canonical Ward identity of the supersymmetric electromagnetic interaction system

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Science china(Physics,Mechanics & Astronomy) 2007年第3期50卷 339-347页

作者： HUANG YongChang1,3.4, JIANG YunGuo1 & LI XinGuo2,3.1 Institute of Theoretical Physics, College of applied Sciences, beijing University of Technology, beijing 100022,{3. 2 Institute of Modern Physics, chinese academy of Sciences, Lanzhou 73.000,{3. 3.Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Collisions, chinese academy of Sciences, Lanzhou 73.000,{3. 4{3. Center of Advanced Science and Technology (World Laboratory), beijing 100080,{3. 1. Institute of Theoretical Physics College of Applied Sciences Beijing University of Technology Beijing 100022 China 3. Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Collisions Chinese Academy of Sciences Lanzhou 730000 China 4. china Center of Advanced Science and Technology (World Laboratory) Beijing 100080 China 2. Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 China

According to the method of path integral quantization for the canonical constrained system in Becchi-Rouet-Stora-Tyutin scheme, the supersymmetric electromagnetic interaction system was quantized. Both the Hamiltonian of the supersymmetric electromagnetic interaction system in phase space and the quantization procedure were simplified. The BRST generator was constructed, and the BRST transforma- tions of supersymmetric fields were gotten; the effective action was calculated, and the generating functional for the Green function was achieved; also, the gauge generator was constructed, and the gauge transformation of the system was ob- tained. Finally, the Ward-Takahashi identities based on the canonical Noether theorem were calculated, and two relations between proper vertices and propaga- tors were obtained.

关键词： supersymmetric electromagnetic interaction BRST quantization Ward identity

INFLUENCE OF CAPILLARITY ON NANO-LITER FLOWRATE MEASUREMET WITH DISPLACEMET METHOD

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Journal of Hydrodynamics 2007年第5期19卷 594-600页

作者： GUO Qiang CHENG Rui SILBER-LI Zhan-hua State Key Laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China Shanghai Institute of applied mathematics and Mechanics Shanghai University Shanghai 200072 China

Nanoqiter flowrate measurements in micro-tubes with displacement method were performed and the effect of capillarity force on the accuracy was investigated through lab experiments and theoretical analysis in this article. The experiments were conducted under the pressure drops ranging from 1 kPa to 10 kPa in a circular pipe with a diameter of 50 pm, to give the pressure-flowrate （P-Q） relation and verify the applicability of the classical Hagen-Poiseuille （HP） formula. The experimental results showed that there existed a discrepancy between the experimental data and the theoretical values predicted by the HP formula if the capillary effect was not considered, which exceeded obviously the limit of the system error. And hence a modified formula for the relation, taking the capillary effect into account, was presented through theoretical deduction, and after the HP formula had been modified the error was proved to be less than 3., which was permitted in comparison with the system error. It was also concluded that only by eliminating the effect of the capillary force in experiments could the original HP formula be employed to predict the pressure-flowrate relation in the Hagen-Poiseuille flow in the micro-tube.

关键词： nano-liter flowrate measurement,Hagen-Poiseuille (HP) formula displacement method,capillarity force

Truncation Analysis for the Derivative Schrodinger Equation

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Acta Mathematica Sinica,English Series 2002年第1期18卷 137-146页

作者： XU Peng Cheng CHANG Qian Shun GUO Bo Ling academy of mathematics and System Sciences. chinese academy of Sciences. beijing 100080. P. R. china Institute of applied Physics and Computational mathematics. P. O. Box 8009. beijing 100080. P. R. china academy of mathematics and System Sciences Chinese Academy of Sciences Beijing 100080 P. R. China Institute of applied Physics and Computational mathematics 8009 Beijing 10080 P. R. China

The truncation equation for the derivative nonlinear Schrodinger equation has been dis- cussed in this paper. The existence of a special heteroclinic orbit has been found by using geometrical singular perturbation the... 详细信息

关键词： Derivative nonlinear Schrodinger equation Geometric singular perturbation theory Melnikov's technique