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在线社交网络中具有传播价值的弱关系识别研究

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情报杂志 2016年第3期35卷 125-130,147页

作者：尹熙成朱恒民魏静马静南京邮电大学管理学院南京210023 南京航空航天大学经济与管理学院南京210016

[目的/意义]鉴于在线社交网络中的部分弱关系在信息传播中扮演了重要角色,提出定量模型来计算和识别具有传播价值的弱关系,以更好地了解网络中信息传播的关系结构。[方法/过程]基于历史交互数据定义了连边权重,运用PageRank算法思想确... 详细信息

[目的/意义]鉴于在线社交网络中的部分弱关系在信息传播中扮演了重要角色,提出定量模型来计算和识别具有传播价值的弱关系,以更好地了解网络中信息传播的关系结构。[方法/过程]基于历史交互数据定义了连边权重,运用PageRank算法思想确定网络中的关键节点,最后对关键节点间的弱关系路径进行重要性评价,以识别具有传播价值的弱关系。[结果/结论]实验表明,弱关系路径使信息能够在以意见领袖为中心的社交团体之间"链式"传播,也从侧面揭示了网络中信息流动的关系结构。

关键词：在线社交网络信息传播弱关系历史交互

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基于生命周期的网店竞争力指标体系构建

南京邮电大学学报（社会科学版） 2016年第4期18卷 70-78,88页

作者：刘静娴尹熙成南京邮电大学管理学院江苏南京210023

构建了网店竞争力指标体系,以淘宝生鲜卖家为实例进行分析,发现处于生命周期不同阶段的网店,其竞争力是有区别的。网店在生存期、发展期和成熟期的不同阶段,竞争能力不断提高。在生存期,网店的产品竞争力和运营力最为重要。在发展期,网... 详细信息

构建了网店竞争力指标体系,以淘宝生鲜卖家为实例进行分析,发现处于生命周期不同阶段的网店,其竞争力是有区别的。网店在生存期、发展期和成熟期的不同阶段,竞争能力不断提高。在生存期,网店的产品竞争力和运营力最为重要。在发展期,网店的营销能力提高幅度最大。在成熟期,网店的成熟度最高。

关键词：电商平台竞争力网店淘宝网生命周期

CTA及其淀粉衍生物的开发与应用(Ⅱ)——CTA阳离子淀粉的研制

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山东建材学院学报 2001年第2期15卷 120-122页

作者：马华宪马希骋尹维英程传格山东大学环境与化学工程学院山东济南250061 山东省分析测试中心山东济南250014

利用合成的 3 -氯 - 2 -羟丙基三甲基氯化铵 (简称CTA) ,对其阳离子淀粉的研制过程进行了较为详细地研究。利用正交实验L9(34 )对合成反应的工艺条件进行了探索 ,并得到了最佳工艺条件A2 B1C1D3;测定了产品的IR谱及其含氮量。IR谱定性... 详细信息

利用合成的 3 -氯 - 2 -羟丙基三甲基氯化铵 (简称CTA) ,对其阳离子淀粉的研制过程进行了较为详细地研究。利用正交实验L9(34 )对合成反应的工艺条件进行了探索 ,并得到了最佳工艺条件A2 B1C1D3;测定了产品的IR谱及其含氮量。IR谱定性表明产品为目标产品 ,产品含氮量为 0 15 %～ 0 5 6 % ,相应其取代度范围为 0 0 18～0 0 70。

关键词： 3-氯-2-羟丙基三甲基氯化铵阳离子淀粉正交实验 CTA

STOCHASTIC HEAT EQUATIONS WITH RANDOM INITIAL CONDITIONS

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Chinese Annals of Mathematics,Series B 2005年第4期26卷 599-610页

作者： ZHANG xicheng Department of Mathematics Huazhong University of Science and Technology Wuhan 430074 China.

In this paper the author constructs a solution of parabolic stochastic partial differential equation with random initial conditions by Kolmogorov's criterion.

关键词： Stochastic partial differential equation Green's function Kolmogorov's criterion

Weak Solutions of McKean-Vlasov SDEs with Supercritical Drifts

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Communications in Mathematics and Statistics 2024年第1期12卷 1-14页

作者： xicheng Zhang School of Mathematics and Statistics Wuhan UniversityWuhanHubei 430072People’s Republic of China

Consider the following McKean-Vlasov SDE:dXt=√2dWt+∫R_(d)K(t,Xt-y)μX_(t)(dy)dt,X_(0)=X,whereμXt stands forthedistributionof Xt and K(t,x):R_(+)×R^(d)→is a time-dependent divergence free vector *** the assumption K∈L_(x)^(p)with weak solutions to the above *** an application,we provide a new proof for the existence of weak solutions to 2D Navier-Stokes equations with measure as initial vorticity.

关键词： McKean-Vlasovsystem Supercritical drift 2D Navier-Stokes equation Krylov’sestimate

Stochastic Hamiltonian flows with singular coefficients Dedicated to the 60th Birthday of Professor Michael R¨ockner

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Science China Mathematics 2018年第8期61卷 1353-1384页

作者： xicheng Zhang School of Mathematics and Statistics Wuhan University

In this paper, we study the following stochastic Hamiltonian system in R^(2d)(a second order stochastic differential equation):dX_t = b(X_t,X_t)dt + σ(X_t,X_t)dW_t,(X_0,X_0) =(x, v) ∈ R^(2d),where b(x, v) : R^(2d)→ R^d and σ(x, v) : R^(2d)→ R^d ? R^d are two Borel measurable functions. We show that if σ is bounded and uniformly non-degenerate, and b ∈ H_p^(2/3,0) and ?σ∈ L^p for some p > 2(2 d + 1), where H_p^(α,β)is the Bessel potential space with differentiability indices α in x and β in v, then the above stochastic equation admits a unique strong solution so that(x, v) → Z_t(x, v) :=(Xt,Xt)(x, v) forms a stochastic homeomorphism flow,and(x, v) → Z_t(x, v) is weakly differentiable with ***_(x,v)E(sup_(t∈[0,T])|?Z_t(x, v)|~q) < ∞ for all q ≥ 1 and T≥ 0. Moreover, we also show the uniqueness of probability measure-valued solutions for kinetic Fokker-Planck equations with rough coefficients by showing the well-posedness of the associated martingale problem and using the superposition principle established by Figalli(2008) and Trevisan(2016).

关键词： stochastic Hamiltonian system weak differentiability Krylov’s estimate Zvonkin’s transformation kinetic Fokker-Planck operator

湖南城步县南山牧场蜱及牛梨形虫病的发生特点

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石河子大学学报（自然科学版） 1997年第2期1卷 139-141页

作者：丁熙成殷佩云姜悦平蒋风英王英中国农业大学湖南城步县南山牧场吉林兽药饲厅

１９９２～１９９６年调查表明，湖南南山牧场寄生于奶牛体内的血液原虫有瑟氏泰勒原虫，传播者为长角血蜱。据流行病学，该病发生在夏秋季。１９９２～１９９４年犊牛５～８月发生，高峰期６～７月；成年牛发生于６～９月，高峰期７～... 详细信息

１９９２～１９９６年调查表明，湖南南山牧场寄生于奶牛体内的血液原虫有瑟氏泰勒原虫，传播者为长角血蜱。据流行病学，该病发生在夏秋季。１９９２～１９９４年犊牛５～８月发生，高峰期６～７月；成年牛发生于６～９月，高峰期７～８月。１９９５年犊牛发生于８～９月，高峰期９月，成年牛发生于８～１０月。病理剖检见皱胃大面积出血，胃粘膜似红布状。用贝尼尔或咪唑苯脲预防注射发病奶牛死亡率由２６％降为５．９％。

关键词：奶牛梨形虫病流行病学湖南牧场

Self-evident Automated Proving Based on Point Geometry from the Perspective of Wu's Method Identity

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Journal of Systems Science & Complexity 2019年第1期32卷 78-94页

作者： ZHANG Jingzhong PENG xicheng CHEN Mao National Engineering Research Center for E-Learning Central China Normal University Institute of Computational Science and Technology Guangzhou University Chongqing Institute of Green and Intelligent Technology Chinese Academy of Sciences

The algebraic methods represented by Wu's method have made signi?cant breakthroughs in the ?eld of geometric theorem proving. Algebraic proofs usually involve large amounts of calculations, thus making it diffcult to understand intuitively. However, if the authors look at Wu's method from the perspective of identity, Wu's method can be understood easily and can be used to generate new geometric propositions. To make geometric reasoning simpler, more expressive, and richer in geometric meaning, the authors establish a geometric algebraic system(point geometry built on nearly 20 basic properties/formulas about operations on points) while maintaining the advantages of the coordinate method, vector method, and particle geometry method and avoiding their disadvantages. Geometric relations in the propositions and conclusions of a geometric problem are expressed as identical equations of vector polynomials according to point geometry. Thereafter, a proof method that maintains the essence of Wu's method is introduced to ?nd the relationships between these equations. A test on more than 400 geometry statements shows that the proposed proof method, which is based on identical equations of vector polynomials, is simple and e?ective. Furthermore, when solving the original problem, this proof method can also help the authors recognize the relationship between the propositions of the problem and help the authors generate new geometric propositions.

关键词： Geometry algebra point geometry proof method based on identical equations vector geometry Wu's method

Singular Brownian Diffusion Processes

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Communications in Mathematics and Statistics 2018年第4期6卷 533-581页

作者： xicheng Zhang Guohuan Zhao School of Mathematics and Statistics Wuhan UniversityWuhan 430072HubeiPeople’s Republic of China Applied Mathematics Chinese Academy of ScienceBeijing 100081People’s Republic of China

In this paper,we survey the recent progress about the SDEs with distributional drifts and generalize some well-known results about the Brownian motion with singular measure-valued *** particular,we show the well-posedness of martingale problem or the existence and uniqueness of weak solutions,and obtain sharp two-sided and gradient estimates of the heat kernel associated with the above ***,we also study the ergodicity and global regularity of the invariant measures of the associated semigroup under some dissipative assumptions.

关键词： Singular drift Weak solution Heat kernel Ergodicity Zvonkin’s transformation