Exam P9

Question 1

What is the fundamental idea behind the Semantic Web? What kind of new possibilities does it aim to unleash?

Answer 1

The main idea behind the Semantic web was the possibility of enabling machines to comprehend the content of the Web. In which the information is given explicit meaning, making it easy for machines to automatically process and integrate information available in the Web

Question 2

What are the main enabling components or layers envisioned for the Semantic Web? List them in the order presented in the “pyramid” diagram

Answer 2

The main enabling components for Semantic Web were Proof, and Logic, which together made the Knowledge Representation Language, and then we had the ontology layer which described the concepts of a domain.

Question 3

What are RDF and RDF Schema? What is the relationship between them, and what purpose do they serve in representing data on the Semantic Web?

Answer 3

RDF is a data model for objects (“resources”) and the relations between them, these data models can be represented in a XML format

RDF Schema is a vocabulary for describing properties and classes of RDF resources

Question 4

What is OWL (Ontology Web Language), and why is it considered the “first level above RDF” needed for the Semantic Web? What capability does OWL provide beyond the basic semantics of RDF Schema?

Answer 4

Above the RDF Schema it is required an ontology language that can formally describe the meaning of the terminology used in Web documents. For machines to be able to preform reasonable tasks on these documents, the language must go beyond the basic semantics of the RDF Schema

Question 5

What are some of the additional vocabularies that OWL introduces for describing properties and classes?

Answer 5

OWL adds more vocabulary for describing properties and classes:
- Relations between classes
- Cardinality
- Equality
- Richer typing properties
- Characteristics of properties
- Enumerated classes

Question 6

What are the three different sublanguages or profiles of OWL mentioned, and what are their distinguishing characteristics in terms of expressiveness and computational guarantees?

Answer 6

Theres’s 3 sublanguages of OWL:

OWL Lite
Supports simple classification hierarchy and simple constraints

OWL DL
Supports the maximum expressiveness while retaining computational completeness and decidability

OWL Full
Supports the maximum expressiveness with the semantic freedom of RDF with no computational guarantees