A QUALITY OF SERVICE ARCHITECTURE FOR REAL-TIME MOBILE-LEARNING SYSTEMS
IEIIT-CNR, National Research Council of Italy (ITALY)
About this paper:
Conference name: 11th International Technology, Education and Development Conference
Dates: 6-8 March, 2017
Location: Valencia, Spain
Abstract:The increasing availability of rich contents from the Internet forces to consider technical network aspects in e/m-Learning applications. Such activities, in fact, can involve high bandwidth demanding contents, such as HQ images or real-time streaming videos; in these cases, a suitable video quality must be guaranteed by the system itself.
In this work, in particular, a real-time mobile learning scenario is considered, where students access the system through whichever device or access technology. In more detail, students follow lessons in real-time, from home or outside, using heterogeneous devices (such as laptops, tablets and smartphones) and different network access connections (such as a WiFi from a 100 Mbps wired, a 20 Mbps DSL or a 10 Mbps LTE).
From a technological viewpoint, this situation is particularly challenging, since every participant must be provided with a suitable quality of service (QoS), to achieve an appropriate fruition of contents. The learning goal, in fact, can be to enjoy rich and detailed contents properly, and HQ images or videos need to be accurately displayed. The problem of visual quality is particularly important, and depends on several factors, such as screen resolution and network access speed.
The aspect faced here refers to lessons involving high bandwidth-demanding contents, such as HD streaming videos, where the bottleneck is data dimension with respect to network access speed. An ad hoc architecture is consequently proposed for the dynamic management of bandwidth release on the basis of content size and duration. The basic principles of such architecture is described in the following.
When a teacher chooses the contents of a lesson, he or she must be aware of possible problems in some students’ connections and devices. For instance, the teacher can use a fast Internet connection, find a beautiful HD image or HD streaming video and decide to ask the pupils to see it. Some students, on their hand, can use slower connections when they follow the lesson from home, access the image or video and see them badly or with several interruptions. The risk, especially where visual quality is fundamental, is that such pupils are not able to follow the lesson properly.
In order to handle with this situation, a possible approach can be the following. On the one hand, the teacher must be prepared (and indicated) which contents he or she can use and which cannot, also on the basis of the students’ technologies. On the other hand, an appropriate schedule of activities, made also on the basis of resources, can prevent the inappropriate fruition of lessons.
In the first part of the paper, the problem is discussed and an architecture proposed for QoS management. In the second part of the paper, an example is discussed where inappropriate choice of connection speed leads to several interruptions and, as a consequence, to an inappropriate lesson development.
In particular, in the proposed architecture two kinds of feasibility controls are made, using information about the students’ access technologies and network traffic predictions. On the basis of such controls, a lesson can or cannot be scheduled.
Keywords: E/m-learning, heterogeneous connections, Quality of Service (QoS).