A Theoretical Multimedia Synchronization Framework for E-Learning System Xiaoye Dai Sabin Tabirca University College Cork Ireland
[email protected] [email protected] Abstract This paper issues the multimedia synchronization framework we developed especially for e-learning system, which is going to solve most educators’ problems that video is weak in supporting cognitive learning. The temporal model introduced in this paper is based on the main video timeline in the learning material and depending on the crucial temporal model other multimedia resources can be synchronized with their different combinations as the user likes. Keywords: multimedia synchronization, temporal model, e-learning
1
Introduction
The new advanced multimedia technologies offer special possibilities for an efficient learning and even collaborative learning. Multimedia computers with exciting capabilities have an enormous impact on education. However, most multimedia programs still fail although they add video and graphics to pageturning programs. Why? The crucial point is the efficiency and effectiveness of your synchronization of the multimedia resources. According to cognitive learning theories, individuals receive information from the environment through a sensory receptor: ears, eyes, nose, mouth or sense of touch, [1]so multimedia educational environment should be designed for compatibility with the human being’s powerful natural learning mechanisms. Although most people have very strong opinions on the use of video in the educational environment ranging from love to pure hatred, they have to accept the conclusion drawn by researches that video presentation strengthens the longterm memory process. [2] A good e-learning system should make full use of multiple media resources effectively to enhance people’s natural learning rather than avoid using video resources. An efficient and effective framework for multimedia presentation is required for creating such an educational environment. Multimedia presentation refers to the presentation of collections of both static data (i.e. text or images) and dynamic data (i.e. audio or video). The synchronization model is the determinative factor of specifying when data or events must occur. Therefore multimedia presentation needs to be assured a proper temporal order for synchronizing different educational data.
1
2
Temporal Model
The main purpose of the temporal model is to capture the presentation time for each data unit. For example, consider the temporal model describing a mentor lecturing with slides. The time that each slide stays in the project depends on the time expended in explanation. [3] These two activities are related in time and this relation/dependency must be predicted by a model of time. Text, images, slides, videos, etc. are defined as different data units in the model. Our synchronization scheme is based on the start and end points of presentable data units and time is a critical notion during the processing. Hereby, the definition of the complete set of temporal relations between two time intervals is very important. Our temporal relations are classified into three main relations which can be expressed by Rbefore, during, after. Let us assume that two intervals are t1 and t2 and take a close look at these three main relations. See(Figure 1)
Figure 1: The complete set of two time intervals relations The temporal mechanism works upon the main video resource timeline since a video clip contains its own timeline which simplifies the framework of synchronization. Other multimedia resources can be synchronized with the main video to assist cognitive comprehension. One example in physical concepts is given in Figure 2.
Figure 2: Other multimedia resources synchronized with video timeline
2
3
Computer Representation Model
The computer representation model is designed to standardize the performance of multimedia application integrated Environment. It deals with the sequential and parallel relation of physical concepts of data units, but for computers they need a mechanical model to send and receive data information. There are two types of relations for a continuous couple of data units in our computer representation model: determinate and indeterminate. The difference between these two types of relations depends on what kind of information they contain. If an exact statement of the starting and end points of data units is given then we define it as quantitative information. Vice versa, if the information is described in a unique way which can yield a range of different realizations then it is qualitative information. The following are two examples of determinate and indeterminate relationships. Example 1: A video of T1 minute duration is presented in parallel with its video title (i.e. it could be other data unit) lasting for T2 minute. Fig.3 presents the relationship for each (S means Starts, E Ends, V Video, and VT Video Title). See(Figure 3)
Figure 3: Example 1: determinate relationship Example 2: There are two data units of unknown duration and they don’t have certain temporal relationship. Fig. 4 presents the relationship for each (S means Starts, E Ends, X Any resources). See(Figure 4)
Figure 4: Example 2: indeterminate relationship The goal of setting up the computer representation model is to simplify the multimedia synchronization performances in computers, so we choose the W3C 3
standard Synchronized Multimedia Integration Language (SMIL) to describe multimedia presentation over the web. The decision made is because SMIL is wildly used in recent internet and it allows the sequencing of audio, video, text and graphic components to be described. The synchronization and layout engine of SMIL could represent the data in the computer representation model into a physical concept. The following examples show how timing could be encoded in both areas. See (Figure 5)
Figure 5: Data unit representations in SMIL Specifications and Physical Concepts
4
Conclusion
In this paper, we develop a simple framework for improving the application of multimedia synchronization in the e-learning system. The theoretical models are drawn from the early research result and at this stage they are being used as a multimedia synchronization mechanism in our e-learning system prototype [4] which is helping the user to design their own multimedia presentation more easily. We hope this system could benefit other interesting researches and applications such as interactive multimedia course design presentation build-up systems, etc.
References [1] Colleen Kehoe, The Information Processing Theory, http://www. kihd.gmu.edu/immersion/knowledgebase/strategies/cognitivism/ informationprocessing.htm, March 8, 1999. [2] Doug Harris, Cognitive Learning And Memory, 1995, http://comp.uark. edu/~jdharris/cogmem.html, 1993. [3] M. J. Perez-Luque and T. D. C. Little, ”A Temporal Reference Framework for Multimedia Synchronization”, IEEE J-SAC, Vol.14, No.1, Jan. 1996. [4] CSL E-learning Online Archive, http://student.cs.ucc.ie/~xd1, January 2006.
4
