1. A computer implemented method for representing temporal knowledge in Resource Definition Framework (RDF), for storing RDF temporal knowledge in a Knowledge Base that is managed by a Knowledge Base Management System (KBMS) that utilizes a Data Base Management System (DBMS), and for querying the temporal knowledge stored in the Knowledge Base, the method includes instructions for at least one of creating a temporal RDF triple, adding that triple to the Knowledge Base and querying the RDF temporal knowledge stored in the Knowledge Base, where the Knowledge Base and the KBMS and the DBMS reside in non-transitory computer-readable medium, the method comprises: creating, in memory, a temporal subject comprising a first value representing a subject, called a Subject Name, and a first period defined by a Begin1 time instant and an End1 time instant where the Begin1 time instant is less than the End1 time instant and where the first period includes all time instants starting from and including the Begin1 time instant up to but not including the End1 time instant; creating, in memory, a temporal object comprising a second value representing an object, called an Object Name, and a second period defined by a Begin2 time instant and an End2 time instant where the Begin2 time instant is less than the End2 time instant and where the second period includes all time instants starting from and including the Begin2 time instant up to but not including the End2 time instant; creating, in memory, a temporal predicate comprising a third value representing a predicate, called a Predicate Name, and a third period defined by a Begin3 time instant and an End3 time instant where the Begin3 time instant is less than or equal to the End3 time instant and where the third period includes all time instants starting from and including the Begin3 time instant up to but not including the End3 time instant; combining, in memory, the temporal subject, the temporal predicate and the temporal object, collectively called as a temporal resource, to form a temporal RDF triple, where the third period is a subset of the overlapping time instants of the first period and the second period; storing in the Knowledge Base one or more of the temporal subjects or temporal objects, after determining the existence and the time reference of the temporal subject or the temporal object, in one column of an Entity Table that has at least one column where a first value in a row of the Entity Table and a second value in a different row of the Entity Table do not have overlapping periods if the Subject Name of the first value and the Subject Name of the second value are the same or if the Object Name part of the first value and the Object Name of the second value are the same; storing in the Knowledge Base one or more of the temporal predicate, after determining the existence and time reference of the temporal predicate, in one column of a Predicate Table that has at least one column where a first value in a row of the Predicate Table and a second value in a different row of the Predicate Table do not have overlapping periods if the Predicate Name of the first value and the Predicate Name of the second value are the same; transforming, in memory, the temporal RDF triple into a quadruple where the first value is a triple Id which is a serial number identifying the temporal RDF triple, the second value is the Subject Name, the third value is the temporal predicate, and the fourth value is the Object Name, and storing in the Knowledge Base one or more of that quadruple in one or more rows of a Triple Table that has at least four columns, one temporal RDF triple for each row; mapping, in KBMS, the Subject Name in a row of the Entity Table and the Subject Name in a row of the Triple table to link these two tables, the Predicate Name in a row of the Predicate Table and the Predicate Name of the temporal predicate in a row of the Triple Table to link these two tables, and the Object Name in a row of the Entity Table and the Object Name in a row of the Triple table to link these two tables; parsing the query to an equivalent SQL query that the DBMS processes.
1. A computer implemented method for representing temporal knowledge in Resource Definition Framework (RDF), for storing RDF temporal knowledge in a Knowledge Base that is managed by a Knowledge Base Management System (KBMS) that utilizes a Data Base Management System (DBMS), and for querying the temporal knowledge stored in the Knowledge Base, the method includes instructions for at least one of creating a temporal RDF triple, adding that triple to the Knowledge Base and querying the RDF temporal knowledge stored in the Knowledge Base, where the Knowledge Base and the KBMS and the DBMS reside in non-transitory computer-readable medium, the method comprises: creating, in memory, a temporal subject comprising a first value representing a subject, called a Subject Name, and a first period defined by a Begin1 time instant and an End1 time instant where the Begin1 time instant is less than the End1 time instant and where the first period includes all time instants starting from and including the Begin1 time instant up to but not including the End1 time instant; creating, in memory, a temporal object comprising a second value representing an object, called an Object Name, and a second period defined by a Begin2 time instant and an End2 time instant where the Begin2 time instant is less than the End2 time instant and where the second period includes all time instants starting from and including the Begin2 time instant up to but not including the End2 time instant; creating, in memory, a temporal predicate comprising a third value representing a predicate, called a Predicate Name, and a third period defined by a Begin3 time instant and an End3 time instant where the Begin3 time instant is less than or equal to the End3 time instant and where the third period includes all time instants starting from and including the Begin3 time instant up to but not including the End3 time instant; combining, in memory, the temporal subject, the temporal predicate and the temporal object, collectively called as a temporal resource, to form a temporal RDF triple, where the third period is a subset of the overlapping time instants of the first period and the second period; storing in the Knowledge Base one or more of the temporal subjects or temporal objects, after determining the existence and the time reference of the temporal subject or the temporal object, in one column of an Entity Table that has at least one column where a first value in a row of the Entity Table and a second value in a different row of the Entity Table do not have overlapping periods if the Subject Name of the first value and the Subject Name of the second value are the same or if the Object Name part of the first value and the Object Name of the second value are the same; storing in the Knowledge Base one or more of the temporal predicate, after determining the existence and time reference of the temporal predicate, in one column of a Predicate Table that has at least one column where a first value in a row of the Predicate Table and a second value in a different row of the Predicate Table do not have overlapping periods if the Predicate Name of the first value and the Predicate Name of the second value are the same; transforming, in memory, the temporal RDF triple into a quadruple where the first value is a triple Id which is a serial number identifying the temporal RDF triple, the second value is the Subject Name, the third value is the temporal predicate, and the fourth value is the Object Name, and storing in the Knowledge Base one or more of that quadruple in one or more rows of a Triple Table that has at least four columns, one temporal RDF triple for each row; mapping, in KBMS, the Subject Name in a row of the Entity Table and the Subject Name in a row of the Triple table to link these two tables, the Predicate Name in a row of the Predicate Table and the Predicate Name of the temporal predicate in a row of the Triple Table to link these two tables, and the Object Name in a row of the Entity Table and the Object Name in a row of the Triple table to link these two tables; parsing the query to an equivalent SQL query that the DBMS processes. 8. The method of claim 1 , wherein the DBMS may be replaced by a relational DBMS, or by a NoSQL DBMS, or by an object relational DBMS, or a native triple store, or by any other DBMS software by changing the definitions of the Entity Table, the Predicate Table, and the Triple Table according to the definitional requirements of these DBMS.