17. The method for creating new concepts in existing ontologies according to claim 16 , wherein if the description parts in a new concept description are Part 1 , . . . , Part n (n>=1); the headwords in each description part are H 1 , . . . , H n ; the concepts and properties in each description part Part i are C i1 . . . , C im and Pro i1 , . . . , Pro iw , respectively, where N>=1, M>=0, and w>=0 and m=0 means no other concept, and w=0 means no property in a corresponding part, then the step of creating the new concept expression comprises the subsets of: 1) for each C ij where 1<=j<=m, finding the shortest path Path ij from H i to C ij , wherein the path should satisfy the following requirements: a) if x>0, it contains some Pro it where 1<=t<=w b) it contains no cycle, c) for any node N i in the path, if N i is a class, it is followed by edge E j ; if E j is a property, the destination must be a class or an instance; and if E j is a superClassOf relation, the destination must be a class; 2) generating a corresponding expression E ij in the certain language by using the shortest path Path ij from H i to C ij ; and 3) combining all expressions E ij in each Part i with corresponding relationships to one combination expression CE i based on relation of AND/OR/NOT among C ij , where j is from 1 to m.
17. The method for creating new concepts in existing ontologies according to claim 16 , wherein if the description parts in a new concept description are Part 1 , . . . , Part n (n>=1); the headwords in each description part are H 1 , . . . , H n ; the concepts and properties in each description part Part i are C i1 . . . , C im and Pro i1 , . . . , Pro iw , respectively, where N>=1, M>=0, and w>=0 and m=0 means no other concept, and w=0 means no property in a corresponding part, then the step of creating the new concept expression comprises the subsets of: 1) for each C ij where 1<=j<=m, finding the shortest path Path ij from H i to C ij , wherein the path should satisfy the following requirements: a) if x>0, it contains some Pro it where 1<=t<=w b) it contains no cycle, c) for any node N i in the path, if N i is a class, it is followed by edge E j ; if E j is a property, the destination must be a class or an instance; and if E j is a superClassOf relation, the destination must be a class; 2) generating a corresponding expression E ij in the certain language by using the shortest path Path ij from H i to C ij ; and 3) combining all expressions E ij in each Part i with corresponding relationships to one combination expression CE i based on relation of AND/OR/NOT among C ij , where j is from 1 to m. 19. The method for creating new concepts in existing ontologies according to claim 17 , wherein the certain language is Description Logic.