Search

In big data era, individuals are surrounded by various kinds of social medium, such as Facebook, Twitter and Microblog. These social media produce vast information every day and support diverse social contagions. However, the dynamics and mechanisms of these social contagions are still obscure and unrevealed because of the big data. In this paper, we propose a novel non-Markovian social contagion model to study behavior spreading under the environment of big data, in which a fraction of global individuals can transmit the behavior information to every susceptible individual, and the remaining local individuals can only transmit the behavior information to neighbors. Through extensive numerical simulations, we find that the global individuals markedly promote the behavior spreading and decrease the critical information transmission probability. In addition, we note that the degree heterogeneity of social network does not change the phenomena qualitatively. Our results may shed some lights in predicting and controlling social contagions. In further, the proposed model may be applied in real simulation platforms for emergency management in big data era.

Dynamic symbolic execution is an important automated testing technique. Firstly, we introduce the traditional symbolic execution and dynamic symbolic execution technology, and then review the research status of Python application testing with dynamic symbolic execution technology. Then we compare and analyze the dynamic symbolic execution tools with the existing Python programs and Architectures, performance, and supported data types. Finally, the development direction of this field prospects. It is helpful for researchers to understand the progress of dynamic symbolic execution technology in current Python program and lay a foundation for future research work.

Communication security is a critical aspect of QoS provisioning in wireless mesh network (WMN). Because of the inherent characteristics of WMN, conventional security mechanisms cannot be applied. In order to guarantee the communication security, a novel communication security mechanism is proposed. The mechanism uses a communication encryption scheme to encrypt data packets and employs a risk avoidance scheme to avoid the malicious nodes during communications. Simulation results indicate that the mechanism is able to provide secure communication effectively and reduce the damage of attacks through multiple paths.

In wireless mesh networks, the connective time would be relatively short in multi-hop nodes because of the mobility of peer nodes and the wireless collision. Therefore, it is important that how peers choose reasonable schemes to gain more benefits and improve the networks performance when they implement the peer-to-peer file sharing in limited environment. On the basis of the researches of peer-to-peer file sharing and the inherent characteristic of wireless mesh networks, a novel venture investment based file sharing model is proposed. The model provides a mechanism to maximize investment benefit and minimize investment venture, and makes optimization investment schemes through a benefit evaluation method. The simulation results show that the venture investment model can assist networks nodes to invest file sharing effectively and improve the performance of networks.

The transmission reliability of wireless mesh network relies on the cooperative and the trusted between the network nodes. To reliable route and forward data packets, it is important to evaluate the trustworthiness of nodes in network But due to the nature of wireless mesh network, the sample space of evidence which is used to evaluate trust may be incomplete or unreliable. So the existing trust evaluation model could not apply to it unalterably. A novel trust evaluation based reliable routing scheme is proposed to solve this problem. It evaluates the trust value of nodes through a novel uncertainty measurement infinitesimal algorithm and discovers reliable routes according to the trust value of nodes. The simulation shows that the proposed model is able to evaluate the trustworthiness of nodes effectively and improve the transmission reliability of the network.