No abstract

A novel system providing effective and efficient access t o video archives for mobile users communicating over low bandwidth error-prone wireless links is proposed. T h e developed system has three components: First, the middleware, implemented as mobile proxy server located a t the mobile support station, is chosen for the seamless integration of both mobile users and video servers by hiding the specific details of the underlying system. Second, for efficient video transmission, our three-dimensional significant-linked connected component analysis video codec well suited for wireless environments, is used. Finally, multilayer transmission error control mechanism is applied to cope with channel errors. As a result, no additional requirements are imposed on the mobile client and video server so that mobile users interact with the server i n exactly the same way as stationary users, and all they experience are better picture qualit,y, less jerky video, and shorter delays.

A novel middleware-based system providing effective and efficient video access for mobile users communicating over low bandwidth error-prone wireless links is proposed. The middleware, implemented as mobile proxy server located at the mobile support station, is chosen for the seamless integration of mobile users and video servers by hiding the specific details of the underlying system. For efficient video transmission, our threedimensional significant-linked connected component analysis video codec well suited for wireless environments, is used. To cope with wireless transmission errors, we propose multilayer error control mechanism, which incorporates synchronization, unequal forward error protection, and retransmission. As a result, mobile users experience better picture quality, less jerky video, and shorter delays when accessing video files. 0-7803-5668-3/99/$10.00 0 1999 IEEE.

Real-time route planning is always a difficulty in maritime traffic. Route planning must take into account the complex meteorological environment. Route planning based on meteorological environment real-time update is the basis of route feasibility. Based on potential field theory, this paper proposes a TPS - Genetic algorithm for real-time route planning of sailing ships. On the basis of genetic algorithm, combined with the characteristics of route planning, the turning point sorting operation is added to improve the calculation efficiency, and further improve the real-time performance of route planning. Simulation experiments are established and compared with A* algorithm. The experimental results show that the potential field theory can accurately express the dynamic changes of Marine meteorology, and the path planned by TPS - Genetic algorithm is more suitable for real-time navigation environment. TPS - Genetic algorithm can be applied to ship navigation system, which can further adjust the potential energy base and plan routes according to the needs of shipping companies.