Research On The Impact Of Human Activity Patterns On The Spreading Processes

The main work of this thesis is the research featuring the influence of human activity patterns and opinion dynamics on the spreading processes based on the complex network theory. There are two spreading processes included in the thesis, the spreading process of epidemic and the spreading process of short message. Either epidemic dynamics or information dynamics is a very important scientific research topic in China. Meanwhile, either of them is no longer a research subject belonging to one single discipline but a cross-disciplinary research subject. The complex network theory has great advantages in the research in terms of those cross-disciplinary subjects. And more importantly, compared with the classics propagation models that place an emphasis on the assumption of uniformly mixing population, complex networks own a better reflection with the statistical properties of real social networks. Therefore, the approach based on a combination of complex network theory and propagation models has become an important trend in researching the spreading processes. Accordingly, in this thesis, exploratory studies that focused on the influence of human activity patterns and opinion dynamics on the spreading processes have been well-explained from both theoretical and emulational levels.The main contents of the thesis are:1) considering the asymptomatic infection characteristics of some certain infectious diseases such as acquired immune deficiency syndrome and chronic viral hepatitis B and then propose a novel epidemic model, i.e., asymptomatic SIS model. Some infected individuals may believe that they are uninfected even when they have been infected asymptomatically, due to the existence of asymptomatic infection characteristics. Therefore, under the circumstances, we need to differentiate the infection awareness states from the physical state of individuals, which have rarely been incorporated into classics epidemic models. Consequently, we propose this model to research the influence of Poisson distribution activity pattern and heavy-tailed distribution activity pattern in terms of the spreading of infectious diseases. According to our results, when the two testing patterns have the same testing frequency, Poisson testing patterns are more effective than heavy-tailed testing patterns in controlling and eliminating asymptomatic infectious diseases.2) Combining A-SIS model and an opinion model based on social impact theory in investigating the impact of epidemic-related opinion dynamics on the spreading of infectious diseases in complex networks. The impact of outcomes of opinion dynamics on the behavior of asymptomatically infected individuals who have known their infected state could not only reduce their transmission probabilities, but also could increase their transmission probabilities. This assumption has rarely been incorporated into the research featuring modeling interaction between epidemic dynamics, opinion dynamics and the change of human behavior. According to our results, when epidemic-related opinion dynamics exist, a higher degree of randomness in the behavior of individuals will lead to a higher prevalence of infectious diseases and a lower social discrimination perceived by infected individuals simultaneously. Furthermore, if the positive external global impact exceeds a certain critical value, there is an abrupt disappearance of infection owing to the contribution of opinion dynamics.3) In order to find some certain factor which influences short message spreading processes, we compare short message propagation on three networks, i.e., scale-free networks, small-world networks and true-life short message network. The topology of short message network and the behaviors of mobile phone users play important roles in determining the behavior of a short message spreading. The impact of scale-free networks on the spread of short messages is mixed:messages spread more quickly than that on small-world networks or true-life short message network but longevity of short message is less than other networks. Some behaviors of mobile phone users obviously influence the process of short message propagation. Meanwhile, we find that the longevity of short message relate to the diameter of networks.