1. A method of machine-based extraction of information from a text document, the method comprising: (a) performing semantic/syntactic analysis for sentences of the document to build semantic-syntactic structures of the sentences; (b) applying production rules to the semantic-syntactic structures to generate a set of logical conclusions about objects of information comprised in the document, wherein the production rules are based on linguistic characteristics and lexical-morphological properties of the semantic-syntactic structures and ontologies of subject matters of the sentences; and (c) using the set of logical conclusions about objects of information comprised in the document to build an ontology-based RDF graph.