Applying Evolutionary Protyping Model in Developing Stream-based Lecturing Systems

Web-based learning courses lack the explanation and interpretation of teaching materials coming from the teacher. According to Theory of Transactional Distance, web-based learning cannot reduce transactional distance if we ignore teacher's explanation and interpretation to teaching materials and just create "dialog" by using communication mechanism like on-line forum, BBS and e-mail. Therefore it’s very important to have teachers’ lectures available online for web-based courses. To solve this problem, we implement a stream-based lecturing system that can fully integrate with web-based teaching materials and recur traditional lecturing situation in limited network bandwidth. We propose three versions of stream-based lecturing system by using evolutionary prototyping development model. Version one is synchronization mode. The drawbacks of this mode are the need of special players for viewing, based-on IE browser, the mismatch of font size, the error of URL path and so forth. To improve these problems, we developed a version two named browser capture mode. It solves most of the problems that version one has, but one main issue remains and that is browser capture mode is still based-on IE browser. Therefore, we are proposing the version three named full screen capture mode. Version three will capture video, audio and annotation into a single streaming video file. Finally, we recommend that version three full screen capture mode is the best solution for delivering teacher’s online lectures. Besides, this paper also indicates that we will be able to achieve the ideal of " Mobile classroom" by making good use of the stream-based lecturing system