Existing schemes in IEEE 802.11 network can only resolve the problems of inner ESS domain, but cannot effectively resolve that of inter ESS domains because the handoff between two ESS domains involve network layer operations. This paper proposes a smooth handoff scheme based on virtual interface in wireless network. This scheme applies a time-sharing policy on physical wireless interface, which enables mobile station to establish new wireless link with the right new access point and to keep normal communication in present wireless link with the previous access point at the same time, so it can perfectly resolve the problems of packet latency and loss ratio for both inner ESS domain handoff and inter ESS domain handoff. Simulation results on NS2 confirmes that it can satisfy the demand of interactive real-time applications in wireless mobile networ
In the research area of Content Based Image Retrieval(CBIR), aiming at extracting the interesting image content to improve retrieval results, this paper proposes an algorithm based on dynamical region pair matching through selecting images by users, uses the Fisher prediction to obtain the dynamical threshold to explore the “interesting” components of the features in the region pair match, adopts those interesting components of the features and the region pairs to retrieve the similar images. The experimental results show the method is effective.
Now, as vulnerability scanning can not fully check out complex attack existing in network, many of the traditional security technologies are no longer valid and failure to prevent effective solutions to modern network security problems from information technology, so many methods based on security model are presented. This paper analyzes the PCI extended ROM specification, the mechanism of network communications link switch, the principle of secret information storage, the connection relation of host computers and devices and the characteristic of attack, presents a novel security architecture of network terminal, which is based on extended ROM and PCI bus to carry out the physics gap of a network terminal between interior and exterior network. It discusses the principle and hardware design of the security isolation card based on PCI bus.