Semantics

Semantic Networks

A  knowledge representation technique that focuses on the relationships between objects. A directed graph (below) is used to represent a semantic network or the net. The nodes of the graph represent the objects, and the arrows between nodes represent relationships. The arrows are labeled to indicate the types of relationships that exist.


Semantic Web = Linked Data

The Semantec web formed of data, like service reviews and type of relationships between people.  Web developers help add structure to social data by using rich snippets in web pages to support markup formats called microformats and RDFa.  

Microformats

Microformats categorize elements with the rel and class attributes. Some popular microformats:

• hCard
• contact data
• hCalendar
• calendars or individual events
• XFN
• personal relations
• rel-license
• hAtom
• news feed
• geo
• latitude/longitude

e.g.

<p class=geo>The Hot Spot at
 <span class=latitude>56.216718</span>
 <span class=longitude>29.305995</span></p>

RDFa 

RDFa syntax:

• noun isa noun
• noun verb
• noun verb object
• noun’s noun verb object

Example without RDFa:

<div>
My name is Erika and I am the original iAmErika. Here is my home page:
<a href="http://www.iamerika.com">www.iamerika.com</a>.
I live in San Diego, CA and work as a Web Developer and Online Marketing Strategist at iAmErika.com.
</div>

Example with RDFa:

<div xmlns:v="http://rdf.iamerika.com/#" typeof="v:Person">
  My name is <span property="v:name">Erika</span>,
  and I am the original <span property="v:nickname"> iAmErika </span>.
  Here is my homepage:
  <a href="http://www.iamerika.com" rel="v:url">www.iamerika.com</a>.
  I live in San Diego, CA and work as a  <span property="v:title">Web Developer and Online Marketing Strategist</span> at
  at <span property="v:affiliation">iAmErika.com</span>.
</div>

Semantic Web Standards