Research On Virus Propagation Model Of Wireless Sensor Networks With Time Delay And Diffusion

Wireless sensor network(WSN)is a wireless self-organizing network formed by a large number of wireless sensor nodes with perceptive capabilities.These nodes use the wireless interface to deliver packet data,and can be served as routers and hosts in this kind of network.With the development of wireless sensor network technology,the WSN has been widely applied in the field of military,medical,building safety,marine environmental monitoring,water quality monitoring and other aspects.Because of the characters of wireless sensor nodes,for instance,the limited power,limited storage space,and using wireless communication method,it is difficult to establish an effect wireless sensor network protection mechanism.In addition,the wireless sensor networks are generally deployed in hostile environments,which can easily cause a variety of targeted attacks on the nodes in the network.Moreover,the attacked nodes will collapse soon,meanwhile the massive attack-packets will result in a great consumption on the limited resource of the network and finally paralyze the network.It is therefore important and urgent to study the wireless sensor network security.In order to further study the spread of the virus in the WSNs,some scholars over the years have adopted the differential equation model to characterize the network processes.However,when a virus is transmitted through a network,the nodes won't be infected instantaneously by the virus.In contrast,there is usually related to time delay in the processes.In particular,the whole system will emerge a more complicated dynamic behavior driven by the time delay.Therefore,it is tempting to explore the effects of time delays on the regulation of the dynamical behaviour in WSNs.According to the characteristics of virus transmission and wireless sensor networks,this paper studies and establishes a model of virus propagation with time delay in WSN.The major work of this thesis is summarized as follows:(1)A delayed wireless sensor virus propagation model is formulated and analyzed.By selecting the latent latency of virus,?,as the bifurcation parameter,the stability and the existence of the Hopf bifurcation of the system are studied by using the Hopf bifurcation theory.Moreover,the direction of the Hopf bifurcation and the stability of the periodic solution of the bifurcation are also determined by using the central manifold theorem and the normal norm law.Finally,some numerical simulations are presented to verify the obtained theoretical results.The obtainedresults show that the latency of network virus infection can change the stability of the system and can produce a series of oscillation behavior even when the system is at a stable steady state.(2)A wireless sensor network virus propagation model with time delay and diffusion terms is formulated and analyzed.Through the research and analysis of the characteristics of mobile wireless sensor networks and virus propagation,adding the time-lag ? to to the virus propagation model to represent the time-delay that result in the process of virus propagation.Moreover,taking into account the mobility of nodes in the mobile wireless sensor network,the Laplace operator(35)to describe the mobility of nodes in wireless sensor networks is introduced.By choosing the time delay ? as the bifurcation parameter,the existence of the Hopf bifurcation and the stability of the system are studied,and some numerical simulations are given to illustrate the obtained theoretical results.Our result shows that even when the system is at a stable steady state,the latency of network virus infection can change the stability of the system and can induce a series of oscillations,including spatially homogeneous periodic oscillations and spatially inhomogeneous periodic oscillations.Finally,numerical examples are presented to illustrate and visualize theoretical results.(3)A simulation experiment of virus propagation with LEACH routing protocol is designed and built by using the OPNET simulation software.We firstly modeled the nodes business layer,network layer and MAC layer by OPNET simulation software,realizing the wireless sensor network virus simulation experiment.Furthermore,we analyzed the data by mathematical tool software MATLAB to verify that when a malicious node exists in the wireless sensor network,the performance of the wireless sensor network will be affected.We showed that when the malicious nodes exist in the WSN and do not process them,it will speed up the node energy consumption and reduce the lifetime of the whole network,and lead to the decrease of the network throughput.In addition,the average time of the infection nodes is also obtained through experiments,which may provide clues to the parameter selection of virus preventive measures in wireless sensor network.The main research content and work of this paper is to add delay and diffusion term on the traditional virus propagation model to establish a virus propagation model that is consistent with the virus propagation characteristics,and analyze the oscillation behavior of the system.On this basis,we simulated the virus propagation in wirelesssensor network based on LEACH routing protocol,and analyzed the influence of virus on the network life cycle and performance.The theoretical results obtained in this paper can guide the understanding of the virus' s propagation characteristics in the network.At the same time,the simulation experiments established in this paper are also valuable for the prevention of virus transmission in the actual network.