The existing authentication schemes based on user social relations have the problems that the user trust computation is not reasonable, the identity voucher is lack of authentication weight and the authentication threshold cannot change with the change of user familiarity. In order to solve these problems, a user social relation-based mobile terminal authentication scheme in cloud computing environment was proposed. Firstly, the user trust was calculated from two aspects of communication trust and attribute trust. And then, the dynamic weights and dynamic authentication thresholds of identity vouchers were set according to user familiarity. Finally, the generation and certification processes of identity vouchers were improved. The experimental results show that the proposed scheme not only solves the problems in the existing authentication scheme based on user social relations, but also reduces the resource consumption of the mobile terminals, which is only a third of the existing methods. Therefore, the proposed scheme is more suitable for the mobile cloud computing environment.

Based on the characteristics of time-varying for the topology of real networks, an online social network was constructed by Twitter data set. Some results were found that the activity distribution of users was virtually independent of the time scale and degree distribution was heterogeneous as well as the side length distribution through analysis. Combined with the characteristics of the network, a spatial activity network model was proposed. The network topology was affected by the activity of nodes and the preferential attachment probability, the accuracy of the mechanism was proved through the analysis of the statistical characteristics. In order to study the dynamic process in time-varying network, a random walk process was carried out in the spatial activity network, the conclusion was obtained that the Mean First-Passage Time (MFPT) was shorter when the node was more active. Finally, the relationship between the preferential attachment power exponent and the average search time was discussed, and it was found that the power exponent with the highest search efficiency was 2 in spatial activity network. The proposed activity network model can be applied to time-varying network.

Combined with virtualization technology, a realization scheme of private cloud platform based on multi-framework technology was put forward in order to improve hardware utilization of distributed cluster system and avoid the economic loss caused by the idle equipment. This scheme met the demand for resource allocation, dynamic allocation and dynamic migration, thus the bottom hardware was integrated. Aiming at unbalanced loading in the traditional virtual machine deployment method, the virtual machine deployment mechanism based on dynamic deployment allocation was proposed. According to the characteristics of virtual machine resources and the load of the current physical nodes, dynamic deployment of virtual machine was carried out. At last, private cloud computing platform with strong flexibility and good scalable performance was realized, which had been tested by Fourier finite difference pre-stack depth migration in oil exploration. The results proved the feasibility and effectiveness of the private cloud platform. By deployment test on virtual machine, the results show that the dynamic allocation decision can be used to deploy a large number of virtual machines, and keep good load balancing of private cloud platform at the same time.

Concerning the lack of refined and quantized real-time evaluation of rainstorm disaster risk level, this paper applied meteorological data, historical disaster data, height and distance from the sea of Guangxi, and confirmed the identification technique and data sequence building method of hazard-formative factors of rainstorm of Guangxi based on hazard-bearing body, the hazard-formative environment, hazard-formative factors, and anti-disaster capability. Real-time evaluation model and grade index of rainstorm disaster risk level based on risk, subsequently environment fragile degree, vulnerability and anti-disaster capability were constructed for different hazard-bearing body, such as agriculture and social economy. And then the rainstorm risk level of real-time evaluation system was developed, with real-time evaluation model as the core. By using the Geographic Information System (GIS) secondary development techniques, the operating process of rainstorm risk level real-time evaluation was simplified and standardized. By using the proposed system to evaluate the violent typhoon named Neuchatel on September 29, 2011, the experimental results show that it is consistent with disaster condition.

Network Time Protocol (NTP) is a simple, economic and efficient way to accomplish time and frequency synchronization of multiple nodes, while relevant study on the performance evaluation is hard to find in literature, which makes it a question whether to use NTP in application. Concerning this problem, the local network NTP performance and impact of system / network load were measured and analyzed on Windows platform. By comparing time value obtained from IRIG-B time code reader and GetLocalTime Windows API, frequency skew of computer clock signal was approximated. The skew value was close to the value calculated by NTP.

Argumentation model is the theoretical basis to establish group argumentation environment. Based on Issue-Based Information System (IBIS) model and Toulmin' argument schema, a group argumentation model was proposed, which was able to evaluate the argumentative utterance. With this model, the group argumentative information could be structured as a graph which consisted of utterance nodes and semantic links. A method of evaluating utterance nodes based on Language Weighted Aggregation (LWA) operator and node reduction was proposed. A group argumentation on the issue of system architecture design was illustrated as an example to show the usability and effectiveness of the proposed model.