Answer Happy

Consider a search engine Sen for news documents. Sen is supported by a crawler Chad. Chad downloads documents from a web of authenticated source-databases producing verified news. The databases are frequently assessed and rated by each other as well by readers of news. Ratings by readers who read a large number of documents from a variety of sources weigh more than ratings by readers who read very little or read only from a limited set of sources. Ratings by sources that are rated high weigh more than ratings by sources that are not rated high. Sen is also supported by an indexing system, Ida. Ida filters documents downloaded by Chad for content free of violence, orders them based on chronology as well as the ratings assigned to the sources (i.e. the databases), and stores them in an inverted index. Explain which of the ranking models among Popularity, Quality, Relevance, Suitability, and Timeliness - are used and how by Sen? [6M]