The digital media platform not only integrates the media resources,but also develops the advantages by combining the repelling medium.

Under the MNI technology,to use multi-media platform may efficiently integrate all subsystems so as to get generic integration,and make a long-term and stable foundation for operation of an intelligent community.

The article mainly focuses on the three aspects of the construction and application of the distance educational service system:the material conditions of open education(planning campus networks and constructing multi-media platforms);the construction of teachers and online teaching resource;the changing of students learning attitude and conception.

Authorware to build platform for multimedia systems,multimedia information system through the needs analysis,from the overall design of the elaborate multi-media platform implementations,the organization of multimedia material and in the Authorware environment should be applied.

Semantically secure digital multimedia cryptosystem;

For implementing the encryption/decryption and information hiding for digital multimedia,and aiming to generate enough large cipher key space,the accurate period of high dimension random matrix scrambling transformation is studied with the help of number theory and algebraic theory.

Starting from a general introductio n of the concepts of information hiding and digital watermarking technology and the fundamental principles,if focuses on representing some typical applications and useful algorithms of information hiding technology to digital multimedia includ ing text, image, audio and video.