In the IPv4/IPv6 transition process, since some legacy IPv4 networks still need to communicate with the IPv6 Internet, the stateless communication mechanism between an IPv4 network and the IPv6 Internet, which complements the current IPv4/IPv6 translation framework, was proposed. First, the communication procedures in two related scenarios were demonstrated. The two scenarios include IPv6 Internet clients accessing IPv4 servers and IPv4 clients accessing IPv6 Internet servers. The one-way IPv6-IPv4 address mapping function is the key component of the mechanism. Therefore, the requirements and three quantitative criteria of the one-way mapping function were discussed. Afterwards, multiple Hash functions as the candidates of the one-way mapping function were compared and analyzed with the real user data of large IPv6 websites and real IPv6 server addresses. The simulation results show that the FarmCity Hash function is suitable to be deployed in the above two scenarios because it has short average processing time, low collision rate and low reverse query complexity. It also verifies the validity of the stateless communication mechanism. Compared with current stateful communication mechanisms, the stateless mechanism has better scalability and traceability. Moreover, the capacity for bidirectional communication facilitates a smooth migration path towards the IPv6 Internet.
In Dynamically Tuned Gyroscope (DTG) system, traditional identification methods, including least square identification method and traditional frequency domain identification method, could not achieve acceptable identification fitness degree. To deal with this problem, outlier-eliminated frequency identification method was proposed. In consideration of the characteristics of DTG model structure and intrinsic colored noise, outlier-eliminated method was applied to DTG frequency domain identification. The experimental results indicate that outlier-eliminated frequency identification method, with a fitness degree above 90%, compared with both least square identification method and traditional frequency domain identification method, has a better performance. In addition, outlier-eliminated frequency identification method possesses of good repeatability and stability. Outlier-eliminated frequency identification method could improve the identification fitness degree of DTG system.
Internet2 Commons is a next generation application framework that encourages deployment of tools for large scale distributed collaborative environment for the research and education community in U.S. The general architecture of design and managing large-scale, distributed videoconference collaborative environment was proposed. Key techniques of H 323-based videoconference system in Internet2 Commons were studied. Ordinary videoconference applications and special videoconference-based applications developed on Internet2 were also introduced. Migration policies of videoconference application from IPv4 network to IPv6 testbed were analyzed and Conclusions were given.
Aimed at image watermark robustness, an evaluative method based on synergetic order parameter and its usage was first advanced. Many kinds of robust experiment of Image carrier were done. After procession, the synergetic original order parameter of patterns in the set were calculated and compared. Through validation by the order parameter evolvement curves, their robust conclusions were gotten. This method is more convenient and applied than the correlative coefficient method, although the two methods have same conclusion.