基于复杂网络的不同路由策略下交通流驱动的流行病传播

2020年,随着新型冠状肺炎在全球范围的蔓延,交通流对流行病传播动力学的影响备受关注。虽然交通流与流行病传播动力学之间的相互作用已经开始受到关注,但路由策略对基于交通流的流行病传播动力学的影响还没有得到足够的重视,因此本文在SI模型上研究了最短路径、有效路径和概率路径三种路由策略对流行病传播动力学的影响。在BA无标度网络模型上进行了仿真实验,结果显示：在节点交付能力无限交通流无拥塞的情况下,相比于最短路径路由策略,概率路径路由策略能有效地抑制流行病的传播,而有效路径路由策略则加速了流行病的传播速度。此外,在上述三种路由策略下,交通流量和传染率的增加都会导致流行病传播阈值的降低,从而加快流行病的爆发。这些研究对控制流行病的传播具有一定指导意义。     

具有非线性传染率的SIS网络传染病模型的稳定性和分支分析简

研究了一类具有非线性传染率的SIS网络传染病模型的动力学行为,给出传播阈值λc=〈k〉/.结果表明,当β0<λc时,无病平衡点E0=0局部稳定;当β0>λc时,无病平衡点E0=0不稳定;进一步分析,当β0=λc时,系统在E0=0处出现Transcritical分支.     

多重网络中信息和病毒交互传播研究

病毒传播过程中,通常伴随着"病毒存在且正在蔓延"的信息传播,而且信息传播机制不同于病毒传播机制。文中利用连续时间马尔科夫过程,描述多重网络中病毒传播和信息传播相互关联动力学,研究信息传播动力学对病毒传播的影响,推导多重网络中的病毒传播阈值。文中方法不仅能够描述社会接触网络中的病毒传播过程,而且能够描述社交网络中的信息传播过程。研究表明,病毒传播阈值不仅与社交网络结构相关,而且与社交网络中的信息传播动力学相关。     

具有非线性传染率的SIS网络传染病模型的稳定性和分支分析

研究了一类具有非线性传染率的SIS网络传染病模型的动力学行为,给出传播阈值λ_c=〈k〉/k(k-1)φ(k).结果表明,当β_0λ_c时,无病平衡点E_0=0局部稳定;当β_0λ_c时,无病平衡点E_0=0不稳定;进一步分析,当β_0=λ_c时,系统在E_0=0处出现Transcritical分支.     

SF网络上的SIR模型

为促进复杂网络和传染病动力学在传染病研究中的应用,分析了SF(无标度)网络的拓扑结构对传染病传播的影响,深入讨论了SIR(易感者一染病者一康复者)模型的传播规律并得到基本再生数Ro.为了进一步控制疾病的传播,采取目标免疫策略,得到了有限的基本再生数Rto.     

BA指数网络结构特性精确计算

度分布和平均路径长度是复杂网络的两个重要结构特性.对于随机增长的网络,其平均路径长度一般主要通过计算机模拟给出数值结果,尚无一个普适的解析计算方法.为此首先利用主方程的方法对BA随机指数网络的度分布进行解析推导,与Barabási等的结果相比所得度分布与计算机模拟值更接近.然后对BA随机指数网络和BA确定性指数网络的平均路径长度进行解析计算,所得结果与经典的ER随机图相似,即平均路径长度以网络大小的对数形式增长.此外,对BA随机指数网络平均路径长度的模拟值与解析计算结果相吻合.最后,对BA确定性指数网络的度分布与直径进行了解析计算,并对两个网络的结构特性作了比较.比较结果表明,BA随机指数网络和BA确定性指数网络的结构性质虽然存在量上的差异,但从定性角度来说,其拓扑结构是相同的.     

一种基于混合依附机制的Internet拓扑演化模型

BA(Barabási-Albert Model)无标度网络属于广义随机网络,不完全符合Internet网络包含大量确定性连接的拓扑特性.在随机偏好依附的基础上混合可调比例的确定性偏好依附,并对确定性连接的择优范围引入变参数控制,提出一种基于混合依附机制的可调幂指数Internet拓扑演化模型.模型的理论解析与数值仿真结果符合良好.模型给出的特征路径长度等网络特征参数与Internet实证数据相符,幂指数在2～3之间可调,是一个更加接近真实Internet网络世界的模型.     

城市公交网络的拓扑特性分析

本文以城市公交网络为研究对象,研究城市公交网络的拓扑特性.以南京市公交网络为实例,建立了南京市公交路线与站点网络的数据库,分别构建了基于公交线路的网络模型、基于邻接站点的网络模型、基于换乘站点的网络模型.利用复杂网络理论分析了这三种网络模型的拓扑结构,通过计算网络的静态参数(特征路径长度、度分布、集聚系数等),分析了不同网络的拓扑特性.利用复杂网络理论研究城市公交网络为城市交通规划与发展提出了新的参考建议.     

实虚部间关联泵噪声对激光动力学性质的影响

在损失模型中引入平方色泵噪声,并考虑泵噪声实虚部间关联λp,推导了一个新的含有λp的光强朗之万方程.用线性化近似的方法从理论上对具有实虚部间关联的泵噪声驱动的单模激光的动力学性质进行分析,计算了光强的关联函数、功率谱及输出功率S.讨论了泵噪声实虚部间的关联强度λp、泵噪声强度p'、净增益系数a和关联时间τ对S的影响,发现λp对光强的输出功率影响显著.当λp=±0.5时,输出功率S最大,|λp|=1或λp=0时,输出功率S最小.     

复杂网络中的SIS传染病模型的稳定性分析

主要研究一类复杂网络中的SIS传染病模型的动力学行为,通过正平衡点的存在性给出传播阈值λ_c=k/k(k-1)φ(k).当λλ_c时,无病平衡点E_0=0全局渐近稳定;当λλ_c时,地方病平衡点E*全局渐近稳定.最后通过计算机数值仿真,验证了理论结果的正确性.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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