Abstract: Disclosed is a system, which grants identification code to sentence structures of electronic teaching material contents, includes the following units. The identification code production unit distinguishes each syllable of electronic teaching material content's selected sentence structure according to type of language, and produces peculiar identification code using the first phoneme or syllable of each syllable. The identification code grant unit grants identification code to metadata of file which stores electronic teaching material contents of above.

Abstract: The invention relates to a multicasting relay method to secure a significantly increased number of simultaneous multicasting connectors under an identical network environment (B-RAS, NAS or the like) with no addition of service device under a modem environment utilizing xDSL and PSTN and a recording medium readably by a computer recorded with programs, the method comprising the steps of: prompting a contents providing server to induce the first xDSL connector terminal to an xDSL server (B-RAS) (step 1); broadcasting a multicasting broadcasting data to the xDSL connector server in real time (step 2); discriminating whether a relevant xDSL ser§ice device supports the multicasting (step 3); broadcasting the multicasting broadcasting data to the first xDSL connector terminal in real time and prompting the xDSL service device to receive the broadcasting data at a multicasting address (step 4); and relaying multicasting data to the second xDSL connector terminal from the xDSL service device of the relevant xDSL ser