Thursday, 9 April 2015

Semantic Web for the Working Ontologist: chapter 1

Ok - here goes.

Chapter 1: What is the Semantic Web?

I now understand the difference between

* URLs (Universal Resource Locators), the "addresses" that enable search engines to locate and show individual web pages
* URIs (Universal Resource Identifiers), that allow search engines to find and link individual items of information within different web pages.

I also know that the "data model" used in the drive towards international consistency in the way that individual pieces of information are described is called the Resource Description Framework abbreviated to RDF. And that an "ontology" is simply the attempt to classify information in a document (or elsewhere) in a way that fits a particular, agreed standard.

I had, of course, heard all those terms before. What I didn't understand was why the standards exist, what they enable to happen, and critically, the assumptions that underpin them…
  • the AAA slogan: Anyone can say Anything about Any topic, which means that we can't assume that
    • two entities with different names are different things
    • two entities with the same name are the same thing
    • different people will agree that the same thing should be classified in the same way
  • the Open World Assumption: there is always more that can be said - which means that we "may draw no conclusions that rely on assuming that the information available at any one point is all the information available." (p10)
A key quote for me from this chapter is "The Semantic Web is… about coping in a world where not everyone will agree, and achieving some degree of interoperability nevertheless." (p9)

Love this acceptance of messiness and the idea of such a huge classificatory project that acknowledges the eternal impossibility of getting everything right, but is still going for it, anyway…

Would be grateful if people could let me know if I've misunderstood anything…

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