Article Preview
Top1. Introduction
All humans have the right to access learning materials and information to improve their quality of life regardless of where they live, their status, and their culture. Mobile learning, through the use of mobile technology, will allow citizens of the world to access learning materials and information from anywhere and at anytime. This idea will literally come true only after a worldwide successful implementation of presentation of device independent learning content (Christ & Feisst, 2010) which should be prepared and saved in the cloud server before (Sultana et al., 2013). Here the cloud services such as Software as a Service (SaaS), and Infrastructure as a Service (IaaS) provide Application and Storage space for the learning content in the cloud.
Cloud computing is an on demand provisioning of software, hardware, and data services achieving economics of scale in IT solutions deployment and operation (Dikaiakos & Katsaros, 2009). The underlying concept of cloud computing dates back to the 1950s, when large scale mainframe became available in academia and corporations, accessible via thin clients / terminal computers, often referred to as “dumb terminals”, because they were used for communications but had no internal computational capacities. To make more efficient use of costly mainframes, a practice evolved that allowed multiple users to share both the physical access to the computer from multiple terminals as well as to share the CPU time. This eliminated periods of inactivity on the mainframe and allowed for a greater return on the investment. The practice of sharing CPU time on a mainframe became known in the industry as time-sharing (Strachey, 1959). In the 1990s, telecommunications companies, who previously offered primarily dedicated point-to-point data circuits, began offering virtual private network (VPN) services with comparable quality of service, but at a lower cost. By switching traffic as they saw fit to balance server use, they could use overall network bandwidth more effectively. They began to use the cloud symbol to denote the demarcation point between what the providers was responsible for and what users were responsible for. Cloud computing extends this boundary to cover servers as well as the network infrastructure (ATM working group, 1993). As computers became more prevalent, scientists and technologists explored ways to make large scale computing power available to more users through time sharing, experimenting with algorithms to provide the optimal use of the infrastructure, platform and applications with prioritized access to the CPU and efficiency for the end users (Corbató, 1962).
The concept of Cloud Computing mainly comprises of five characteristics, three service models, and three deployment models as shown in Figure 1.
Figure 1. Cloud characteristics, service models, and deployment models (Marepalli et al., 2013)
The identified barriers that have to be taken care of to support mobile learning in cloud are: 1) various kinds of devices used by different users or in different times or parallel by the same user which is not predictable and have to be recognized by the system in order to know device capabilities. In a stable place like at home or at office it is more convenient to use a PC. While on the move it is very obvious that a user would like to access same content with the same outlook and feel by using his mobile device. So a system is necessary which is device dependent from the point of communication functionality, interactivity, 3D capabilities, and information presentation and information depth. But at the same time it must be device independent from the point of information access. 2) The overall number of users of specialized content or interactive applications is too low to adapt the application/content to all possible devices manually. 3) Content and User Interfaces could include different kinds of data format like text, image, audio, video, 3D Virtual Reality data and upcoming other formats. The system should be able to deal with all the existing and upcoming formats of data without requiring any huge enhancement.