Design And Implementation Of The Broadband Oriented Cross-platform Digital Learning System

In recent years, digital media, communication and information technology have grown to a new stage. The updating and blending of the fixed, mobile and CATV network bring digital media a new reform. Fixed network is broad banding, high-speed Internet network can load high-quality and abundant television content. Mobile network is evolving to broad band and multimedia, new business and new technology emerge in endlessly. Cable networks which can provide more abundant channel programs are also ongoing and doing digital and interactive alteration. Users are looking for seamless service, that is, every business can be provided to every terminal through every network. A high interactive, individual and seamless platform is the key to realize all this. The blending of TV and broadband network, and the blending of stationary and mobile, and seamless final user experience is the tendency of digital media.This paper presents a scheme of a broadband oriented and cross-platform digital learning system, which supports multiple terminals such as new broadband network and mobile equipments. Based on the researches of common education environment, multi-mode interaction and feedback, multi-streaming and multi-terminal grade transmission, the system builds a new common education environment made of natural teaching which based on smart space, cross-terminal and multi-mode interaction and multi-terminal seamless roaming. The system meets the needs of learners to acquire digital media contents; it provides conditions of more modern distance education system. This system is the research project of Shanghai Jiaotong University organized by the Science and Technology Committee of Shanghai, which can be the digital learning operation platform based on broadband network and provide technical support and digital learning appreciation service for many kinds of digital learning content providers and broad users. The system has been successfully used on distance education in Network Education College, Shanghai Jiaotong University, and obtains good results.This thesis mainly describes the innovative work in the following areas:First, we implemented intelligent, real and natural teaching technology, which includes automatic tracking of teacher's video, human face detection, recognizing of speech command, laser pen writing, intelligent direct broad cast, remote monitoring and attention detection. Teachers can teach freely by traditional customs.Second, we implemented real-time interaction technology in cross-terminal digital learning, which builds learners virtually space for exchange and makes different terminal learners acquire freely communication by watching learning contents and resolved the interaction service problem on the multi-terminal and cross-network audio and video. Third, we implemented cross-platform development and implemented the blending of education business on three typical user terminals as PC, network TV and mobile terminals, which provides favorable conditions for one user to learn seamlessly between different terminals.Fourth, we solved the data consistency problem on seamless learning between multiple terminals, which may save and share all study information and status of users on different terminals and makes learners continue last time study schedule and provides grade transfer mechanism according to current context.Finally, we ensured scalability and used scalable architecture to design tight coupling, which ensure self-adaptive on the expanding requirements..