**1. Introduction**

The web has evolved through many stages. Contents on the Web have been changed in both form and method. Searching for information on the Web with keywords is very limited. In the future, we will have a lot of information, causing the traditional search to be insufficient. To perform a better search, the semantic of information must be exploited. One way to represent such concept is to use Linked Data. The conversion of already abundant data into the Linked Open Data format will allow the intelligent search. This extension technology of the Web is called the Semantic Web.

This chapter will briefly introduce the Semantic Web and underlying technologies, including the fundamental element of the Semantic Web called Resource Description Framework (RDF). Currently, there are many different forms of information on the web. So, there is a lot of research related to the conversion of these
