This paper proposes a novel additive increase and multiplicative decrease (AIMD) algorithm for wireless video transmission over cellular networks. The goal of this new algorithm is to improve the bandwidth utilization efficiency without degrading its fairness potential. To address this issue, it increases the regulating segment during the fast-recovery stage, and uses a time-window-based adjusting scheme to filter the short-time-slot bandwidth fluctuation. Simulation results show that the proposed algorithm has faster bandwidth recover speed and less transmission rate fluctuation than that of the traditional AIMD algorithm.

To support content based image retrieval, MPEG-7 is developed to define the content interfaces for images. In MPEG-7, Dominant Color Descriptor (DCD) is considered as the most important feature, and is widely used to describe the color features of an image. To support semantic queries from users, we proposed a color feature semantic mapping method in this work, which can translate the DCD values into semantic color names. The semantic mapping method is realized by constructing a mapping table between the DCD values and the semantic color names. To validate the effectiveness of our mapping method, an image retrieval experiment is conducted. From the comparison with the manually indexed description, the proposed mapping method is proved to be effective by the experiment results. Our work is very important to automatically generate the semantic description of an image and then support the users’ semantic retrieval queries.