Attempt FIVE questions from this section. Section A is worth 50 marks. 1. Illustrate the main principles behind the Page Rank model for searching very large document corpora. Describe tbe mathematical equation modelling the general case. (10 marks) 2. Provide the definition of simple entailment for RDF(S). Why is simple entailment important in query answering? (10 marks) 3. Explain tbe relationship between tbe following three (families of) languages: RDFS, OWL Lite and OWL-DL. (10 marks) 4. Describe the benefit of formulating competency questions in order to start tbe process of ontology modelling, and of specifying an ontology using a forma/language. Clarify the meaning of formal in this context. Provide at least four examples of competency questions for a domain and task of your choice. (10 marks) 5. Online advertising is a form of marketing that delivers messages over the WWW. Describe tbe pay per click model and its associated revenue model. (10 marks)