Abstract:

In this paper, we present an innovative Visual Programming Component (VP component) of a Learning Management System (LMS) that allows adjusting the system functionality to particular teacher requirements by means of actual programming of e-learning scenarios.
The VP component is built on a base of so-called AJAX architecture. The architecture distinguishes back-end and front-end layers. In our case, the back-end layer can be seen as a number of registered web services that provide an interface between the VP component and the LMS as such. The VP component serves as the front-end layer and interprets e-learning scenarios defined in terms of a special Visual Programming paradigm. The paradigm is supposed to be used by teachers who do not possess a deep programming knowledge but would desire to implement an innovative functionality of LMS themselves. Moreover, the LMS can be further adapted to particular user requirements without interruption of previously implemented functionality by means of trivial modifications of the scenario definitions.
The method is essentially based on a novel paradigm for visual programming of e-learning scenarios. In accordance with this paradigm, an e-learning scenario is built as a number of so-called frames connected by a number of channels into a network structure. The frames encapsulate concrete imperative actions and can be activated in an asynchronous way by means of events generated by the frames and propagated over the channels.
A certain frame consists of three basic components:
• Switcher - a logical condition that is defined on elements received from a channel.
• Body- a set of particular imperative operations
• Frame Socket - a request to carry out one or many of the methods defined on the back-end layer of the system.

Frames are defined by selection and filling special templates. Additionally, a particular combination of JavaScript variables, statements and user interface elements can be added to the frame definition, for example, HTML forms and input elements. Thus, the programming is carried out by interactive selection of templates, filling the templates with particular data and combining templates by means of channels. The special authoring system allows to visualize the frame-channel structure and to carry out all the above-mentioned operations in an interactive way.
First experiments with the VP component show that the most favourite way of using the component by teachers is a regime of adjusting existing scenarios to particular needs by tiny modifications of the frame-channel structure. Thus, for example, the first version of a scenario for uploading of student assignments was implemented by experienced programmers and offered to teachers as a source file. About 30% of teachers make small modifications in the scenario and only then offered it to students.

Keywords:

WEB application, Learning Management System, Architecture.