Learning and navigation assistance in a hypermedia.

INTRODUCTION

One notes that in hypermedia, sites appear and disappear, content is modified and it becomes impossible to master its organization. On the other hand, the web made it possible, in some learning situations, for the learner to construct her/his individual progression. One speaks thus of navigation activity to get content or to locate oneself and choose information resources. Nevertheless, if the web offers a huge potential for distance learning because of the high degree of interactivity and connectivity allowed, it also possesses a number of navigation limitations.

In fact, the navigation process on the web is confronted by three major problems. First, the nature of the environment itself imposes some disadvantages. The Internet is a network on a worldwide level which is constantly changing and non-structured. Next, Navigators generally have difficulties in constructing a mental navigation outline. At last, the computer aided tools for navigation offered by different classical software do not satisfy user needs, and sometimes contribute, paradoxically, to make the navigation process more confusing. The conclusion from the analysis of these problems is to develop new computer aided tools for navigation. These tools will have to be able to address the following two main questions usually asked by the user: "which link to follow?" and "how to retrieve this page?". The Internet representation tools and the user navigation path visualization are certainly answers provided by current and feature developments.

The remaining sections of our paper are organized as follows: first we define the terms: hypertext, hypermedia, navigation and orientation that will be used throughout the paper. Next the hyper-text navigation notion and Internet usage for remaining purpose will be given particular attention. After that we discuss the general problems related to the navigation on the Web and other difficulties encountered. Finally, we present and compare the main computer aided tools for navigation available in the literature.

HYPERTEXT AND HYPERMEDIA

In brief, we can say that hypertext is a system that allows different information to be presented in a non-linear manner. Hypertexts are made of nodes and links. Nodes (hypertext pages) are constituted of textual information. Links form bridges between the pages: a word (or a set of words) is marked in a special way, indicating to the user the possibility of displaying another page by activating this link. The Nodes content is what differentiates hypermedia and hypertexts. In this case, the nodes contain only textual data, but can be composed of various media, such as images, animated sequences, video, etc. Nevertheless, some authors do not differentiate between the use of the terms hypertext or hypermedia to show that the main interest of these systems is not the content but the hyper-space global structure.

The Hyper-textual Navigation