RDFa basics for who would like to get to know RDFa

1. RDFa 1.1 Basics
Rich Structured Data Mark-up for Web
Documents

2. What Browsers see What Humans see
▶ The missing piece is the meaning of the web page’s visual elements
 What’s the missing piece of the web?

3. What Browsers see What Humans see
▶ RDFa is a bridge between the Web of Documents and the Web of Data
 What’s RDFa?
Add machine-readable
hints to webpage

4. Add machine-readable
hints to webpage
 RDFa Example
▶ By adding machine-readable hints (property like
“title” and “created”, which are well-defined
vocabularies in the described (URI) resources,
browsers be could able to know the meaning that
can be represented as triples.
▶ By adding machine-readable hints (property like
“title” and “created”, which are well-defined
vocabularies in the described (URI) resources,
browsers be could able to know the meaning that
can be represented as triples.

5.  Problem#1 : Isn’t it so difficult to add so long property value for
every single element?
▶ RDFa alleviate the problem by setting default
vocab attribute to let the author declare a single
vocabulary for a chunk of HTML.
▶ RDFa alleviate the problem by setting default
vocab attribute to let the author declare a single
vocabulary for a chunk of HTML.
Setting default vocab

6.  Vocab attribute example
The first vocab attribute
The second vocab attribute
▶ The vocab in the license paragraph overrides the definition inherited from the
body of the document.
▶ The vocab in the license paragraph overrides the definition inherited from the
body of the document.

7.  Example with FOAF vocabulary

8.  Example with FOAF vocabulary

9.  Problem#2 : What if there’s repeated pattern?

10. ▶ RDFa alleviate the problem by using rdfa:copy and the magic type rdfa:Pattern▶ RDFa alleviate the problem by using rdfa:copy and the magic type rdfa:Pattern

11.  Problem#3 : How to make internal reference?
If the left Alice could be refer to the right Alice
resource which already is described with
RDFa mark-up, the browser could know the
Alice is the person we already described in
the right as well.
If the left Alice could be refer to the right Alice
resource which already is described with
RDFa mark-up, the browser could know the
Alice is the person we already described in
the right as well.

12.  Problem#3 : How to make internal reference?
▶ The resource attribute appears, in this case, together with property on the same
element: in this situation resource indicates the target of the relation.
▶ The resource attribute appears, in this case, together with property on the same
element: in this situation resource indicates the target of the relation.

13.  Problem#4 : How to use multiple vocabularies?
- it will be complicated if we use different vocabularies interwined and in different places of the webpage

14.  Problem#4 : How to use multiple vocabularies?
▶ RDFa offers the possibility of using prefixed terms: a special prefix attribute can
assign prefixes to represent URLs and, using those prefixes, the vocabulary
elements themselves can be abbreviated. The prefix:reference syntax is used: the
URL associated with prefix is simply concatenated to reference to create a full URL.
▶ RDFa offers the possibility of using prefixed terms: a special prefix attribute can
assign prefixes to represent URLs and, using those prefixes, the vocabulary
elements themselves can be abbreviated. The prefix:reference syntax is used: the
URL associated with prefix is simply concatenated to reference to create a full URL.

15.  RDFa Tool