Method and system of combining knowledge bases

1. A computer implemented method of combining two knowledge bases, each knowledge base comprising concepts that are linked by relations, the method comprising:

assigning one of the two knowledge bases as a first knowledge base and the other as an additional knowledge base;

matching concepts between the first knowledge base and the additional knowledge base to define mapping relations between concepts of the first and additional knowledge bases;

assessing the defined mapping relations to determine if any mappings cause a violation with relations already present in the first or additional knowledge base;

modifying relations within the additional knowledge base to repair violations; and

storing an extended first knowledge base comprising the first knowledge base, the defined mapping relations and the additional knowledge base with the modified relations within the additional knowledge base,

wherein mappings that cause the violation are determined to be mappings that cause the violation with relations already present in the first knowledge base,

wherein the modifying relations within the additional knowledge base comprises at least two options for repairing the violation and each option comprises removing an axiom from the additional knowledge base, the violation being repaired by removing the axiom in one of the two options that causes the lowest amount of changes to the first knowledge base.

2. The method according to claim 1 , wherein the assessing defined mapping relations comprises assuming that the violation stems from exactly two mappings which map concepts between the first and additional knowledge bases.

3. The method according to claim 2 , wherein the modifying relations within the additional knowledge base comprises assuming that each violation to be repaired stems from exactly two mappings which map concepts between the first and additional knowledge bases.

4. The method according to claim 1 , wherein mappings that cause the violation are determined to be mappings that cause the violation with relations already present in the additional knowledge base.

5. The method according to claim 4 , wherein prior to repairing the violation, determining whether the violation needs to be repaired.

6. The method according to claim 5 , further comprising determining not to repair the violation if two concepts in the additional knowledge base to which mappings cause the violation are descended from a common concept.

7. The method according to claim 5 , further comprising determining not to repair the violation if two concepts in the additional knowledge base to which mappings cause a violation are similar.

8. The method according to claim 4 , further comprising determining if two concepts in the additional knowledge base to which mappings cause the violation are disjoint.

9. The method according to claim 8 , wherein the violation caused by two disjoint concepts in the additional knowledge base is repaired by either removing the disjoint axiom or removing a mapping.

10. The method according to claim 4 , wherein the violation is repaired by removing a mapping.

11. The method according to claim 1 , further comprising separating mappings that cause a conflict into two groups prior to the modifying relations, wherein:

a first group comprises mappings where two or more concepts from one knowledge base are mapped to a single concept in the other knowledge base; and

a second group from mappings comprising the remaining mappings not in the first group.

12. Th method according to claim 11 , wherein the mapping relations between the first and additional knowledge bases are modified to resolve conflicts for the first group.

13. The method according to claim 1 , wherein the two knowledge bases are medical knowledge bases.

14. The method according to claim 1 , wherein the two knowledge bases are stored in memory in a form of triple stores.

15. The method of proving a response to a query, the method comprising:

using a probabilistic graphical model to query a knowledge base, wherein the knowledge base is constructed from at least two knowledge bases combined as recited in claim 1 .

16. The non-transitory computer-readable storage medium including instructions stored thereon that, when executed by a computer, cause the computer to perform the method of claim 1 .

17. A computer system adapted to combine two knowledge bases, each knowledge base comprising concepts that are linked by relations, the computer system comprising:

a storage comprising the two knowledge bases; and

a processor, the processor being configured to:

assign one of the two knowledge bases as a first knowledge base and the other as an additional knowledge base;

match concepts between the first knowledge base and the additional knowledge base to define mapping relations between concepts of the first and additional knowledge base;

assess the defined mapping relations to determine if any mappings cause a violation with relations already present in the first or additional knowledge base;

modify relations within the additional knowledge base to repair violations; and

store in the storage an extended first knowledge base comprising the first knowledge base, the defined mapping relations and the additional knowledge base with the modified relations within the additional knowledge base,

wherein mappings that cause the violation are determined to be mappings that cause the violation with relations already present in the first knowledge base,

wherein the modifying relations within the additional knowledge base comprises at least two options for repairing the violation and each option comprises removing an axiom from the additional knowledge base, the violation being repaired by removing the axiom in one of the two options that causes the lowest amount of changes to the first knowledge base.