“网络水军”与旅游目的地网络形象——基于“病毒传播”模型的动态系统仿真研究

在新媒体时代背景下,发挥网络正向引导旅游目的地网络舆论的作用、提高旅游目的地网络风险防范和舆情管控、营造良好的旅游城市网络形象,是旅游目的地网络工作的首要任务。基于此,本文通过阐述影响旅游目的地网络舆论传播群体"网络水军"的概念,基于"病毒传播"模型探究"网络水军"影响普通网民群体的模式和途径,构建"网络水军"影响旅游目的地网络舆论传播模型;随后对"网络水军"影响旅游目的地网络舆论传播模型进行动态系统仿真,模拟"网络水军"如何通过影响普通网民群体及影响旅游目的地网络舆论传播的具体机制。本文仿真模拟结果显示,旅游目的地当地政府应当构建以预防为主的网络舆情预警机制,同时在特定时间节点及时介入切断"网络水军"影响普通网民的渠道,阻断网络舆论传播的路径,从而前瞻性地管控旅游目的地网络舆论的走向。

Modeling of Malicious Code Propagations in Internet of Things

Nowadays, the main communication object of Internet is human-human. But it is foreseeable that in the near future any object will have a unique identification and can be addressed and con- nected. The Internet will expand to the Internet of Things. IPv6 is the cornerstone of the Internet of Things. In this paper, we investigate a fast active worm, referred to as topological worm, which can propagate twice to more than three times faster tl^an a traditional scan-based worm. Topological worm spreads over AS-level network topology, making traditional epidemic models invalid for modeling the propagation of it. For this reason, we study topological worm propagation relying on simulations. First, we propose a new complex weighted network mod- el, which represents the real IPv6 AS-level network topology. And then, a new worm propagation model based on the weighted network model is constructed, which descries the topological worm propagation over AS-level network topology. The simulation results verify the topological worm model and demonstrate the effect of parameters on the propagation.

System Recovery-Aware Virus Propagation Model and Its Steady-State Analysis

Network structures and human behaviors are considered as two important factors in virus defense currently. However, due to ignorance of network security, normal users usually take simple activities, such as reinstalling computer system, or using the computer recovery system to clear virus. How system recovery influences virus spreading is not taken into consideration currently. In this paper, a new virus propagation model considering the system recovery is proposed first, and then in its steady-state analysis, the virus propagation steady time and steady states are deduced. Experiment results show that models considering system recovery can effectively restrain virus propagation. Furthermore, algorithm with system recovery in BA scale-free network is proposed. Simulation result turns out that target immunization strategy with system recovery works better than traditional ones in BA network.

Susceptible-Infected-Recovered-Susceptible Virus Spreading Model Based on Two Dimensional Sparse Lattice

In order to clarify the virus＇ spreading rules, a SIRS （Susceptible-Infected-Recovered-Susceptible） disease spread model based on sparsely distributed crowd is proposed. In this model, the effects of crowd-density, spread efficiency and the moving of individuals on the spreading of viruses are researched. The theoretical analysis and analog simulation shows that there exist a critical value, only when the product of spread efficiency and crowd density goes beyond the critical value, can viruses spread in crowd continuously and steadily. Besides, the moving of individuals can promote the spreading of viruses. These results are helpful guiding people to defense and control virus＇ spreading process.

Modeling active worm propagation on the P2P network

This paper analyzes the characteristics of the Peer-to-Peer （P2P） active worm and its attacking mechanism, and then proposes a mathematical model of propagation of the P2P active worm applying Epidemiology. Based on the analysis on the protocols of realistic P2P systems, a software which can be used to simulate the P2P network environment and the propagation of P2P active worm is imple- mented in this paper. A large number of simulation experiments are performed using the developed simulation software. The results from these simulation experiments validate the proposed model, which means that the model can be used to analyze the spreading behaviors of the P2P active worm and predict its trend.

Spreading and vanishing in a West Nile virus model with expanding fronts

We study a simplified version of a West Nile virus （WNv） model discussed by Lewis et al. （2006）, which was considered as a first approximation for the spatial spread of WNv. The basic reproduction number R0 for the non-spatial epidemic model is defined and a threshold parameter RD for the corresponding problem with null Dirichlet boundary condition is introduced. We consider a free boundary problem with a coupled system, which describes the diffusion of birds by a PDE and the movement of mosquitoes by an ODE. The risk index R0^F（t） associated with the disease in spatial setting is represented. Sufficient conditions for the WNv to eradicate or to spread are given. The asymptotic behavior of the solution to the system when the spreading occurs is considered. It is shown that the initial number of infected populations, the diffusion rate of birds and the length of initial habitat exhibit important impacts on the vanishing or spreading of the virus. Numerical simulations are presented to illustrate the analytical results.

MODELING THE SPREAD OF HIV IN A STAGE STRUCTURED POPULATION： EFFECT OF AWARENESS

Human immunodeficiency virus （HIV） is a lenti-virus （a member of the retrovirus family） that causes acquired immunodeficieney syndrome （AIDS）, a critical condition in humans in which progressive failure of the immune system allows life-threatening opportunis- tic infections. Over the past few years HIV has been spreading rapidly in the popula- tion. Almost, everyday there are thousands of new human cases of HIV infection being recorded in the world and these occur in almost every country of the world. However, the spread of HIV is relatively faster in the developing countries as compared to developed countries because developing countries have limited resources. Worldwide, 70% of HIV infections in the adults have been transmitted through heterosexual contact and vertical transmission accounts for more than 90~ of global infection in infants and children. In this paper, we propose a nonlinear mathematical model to study the spread of HIV by considering transmission of disease by heterosexual contact and vertical transmission. A stage structured model is proposed and analyzed by considering the total population variable and dividing the whole population under consideration into three stages： chil- dren, adults and old. Also, in this paper it is assumed that the rates of recruitment are different in different groups of population. Equilibria of the model and their stability are also discussed. Using the stability theory of differential equations and computer simu- lation, it is shown that due to the increase in the awareness of the disease in the adult class the total infective population decreases in the region under consideration.

Comparison between chikungunya and dengue viruses transmission based on a mathematical model

Chikungunya and dengue viruses are transmitted by mosquitoes of genus Aedes. Based on a mathematical model dealing with arboviruses transmission that encompasses human and mosquito populations, the risks of dengue and chikungunya infections are compared. By the fact that chikungunya virus attains high viral load earlier than dengue virus in both humans and mosquitoes, the potential risk of chikungunya could be higher than the dengue infection. The risk of arboviruses infections is assessed by the reproduction number R, which is obtained by the next generation matrix method and Routh-Hurwitz criteria.