Query relaxation using external domain knowledge for query answering

1. A non-transitory computer readable storage medium tangibly embodying a computer readable program code having computer readable instructions that, when executed, cause a computer device to execute a method of query relaxation, the method comprising:

receiving a query from a conversational system;

identifying at least one search term in the query;

outputting instance data to the conversational system in response to determining that the instance data in a data store matches the at least one search term in the query;

in response to determining that the at least one search term does not match the instance data in the data store, performing, by the computer device, a hybrid search of an external domain-specific knowledge source, the hybrid search comprising a radius approach, a similarity measure, and statistical information usage based on word frequency to find relaxed data matches that are semantically related to the at least one search term in the query; and

generating, by the computer device, a response to the query based on contextual information and structural information based on the relaxed data matches found from the hybrid search.

2. The non-transitory computer readable storage according to claim 1 , wherein the relaxed data matches are semantically-related terms received by the computer device based on structural information obtained from the external domain-specific knowledge source, the contextual information obtained from the query, and information content of the query.

3. The non-transitory computer readable storage medium according to claim 1 , wherein the external domain-specific knowledge source includes data in a form of at least one of taxonomies, ontologies, or semantic networks.

4. The non-transitory computer readable storage medium according to claim 1 , further comprising indexing data values stored in the data store with the instance data.

5. The non-transitory computer readable storage medium according to claim 1 , further comprising ingesting the external domain-specific knowledge source into a graphic database.

6. The non-transitory computer readable storage medium according to claim 1 , wherein the external domain-specific knowledge source is grouped in terms of concept, relation, and description.

7. The non-transitory computer readable storage medium according to claim 1 , wherein the instance data includes variations of semantically-related data obtained from the data store.

8. A system configured to perform query relaxation, comprising:

a plurality of data stores;

a translation index configured to:

receive a query output from a conversational system;

provide instance data indexing to data values stored in the plurality of data stores and to semantically related terms;

identify at least one search term in the query; and

output an instance data to the conversational system in response to determining that the data in the data stores matches the at least one search term in the query; and

an external domain-specific knowledge index configured to:

in response to determining that there is no match in the data stores of the at least one search term, performing a hybrid search comprising a radius approach, a similarity measure, and statistical information usage based on word frequency to find relaxed data matches that are semantically related to the at least one search term in the query; and

output the query to an external domain-specific knowledge source; and

receive and wherein the system generates a response to the query based on contextual information and structural information based on the relaxed data matches found from the hybrid search.

9. The system according to claim 8 , wherein the external domain-specific knowledge source includes data in a form of one or more of taxonomies, ontologies, or semantic networks.

10. The system according to claim 8 , further comprising a graphic database into which the external domain-specific knowledge source is ingested.

11. The system according to claim 8 , wherein the instance data includes variations of semantically-related data obtained from the data stores.

12. The system according to claim 8 , wherein the external domain-specific knowledge index is further configured to process relaxed data received from the external domain-specific knowledge source to determine one or more instance-concept frequencies in the external knowledge source and to determine one or more deep hierarchies in the external knowledge source.

13. The system according to claim 12 , wherein the external domain-specific knowledge source is instance-concept frequency populated.

14. The system according to claim 8 , wherein the translation index is further configured to parse entities and intents in the query received from the conversational system.

15. The system according to claim 8 , further wherein the configured to determine concepts, relationships, and descriptions of the external domain-specific knowledge source.

16. The system according to claim 15 , further configured to determine an hyponymy relation (isA) between classes and subclasses of the structural information, wherein the similarity is calculated according to:

IC

⁡

(

c

)

=

-

log

⁢

(

freq

⁡

(

c

)

)

;

⁢

freq

⁡

(

c

)

=

❘

"\[LeftBracketingBar]"

c

❘

"\[RightBracketingBar]"

+

∑

i

=

1

n

❘

"\[LeftBracketingBar]"

c

i

❘

"\[RightBracketingBar]"

;

⁢

sim

IC

(

c

1

,

c

2

)

=

2

×

IC

⁡

(

l

⁢

c

⁢

s

⁡

(

c

1

,

c

2

)

)

IC

⁡

(

c

1

)

+

IC

⁡

(

c

2

)

;

⁢

p

c

1

,

c

2

=

∏

i

❘

"\[LeftBracketingBar]"

D

❘

"\[RightBracketingBar]"

w

i

D

-

i

;

⁢

sim

⁡

(

c

1

,

c

2

)

=

p

c

1

,

c

2

×

sim

IC

(

c

1

,

c

2

)

;

where:

IC is the Information Content,

|D| is a distance between instance concept c1 and related concept c2, and

wi is the weight of the i th relationship from c1 to c2.

17. A computer implemented method of performing query relaxation, the method comprising:

receiving, by a computer device, a query output from a conversational system;

identifying, by the computer device, at least one search term in the query;

outputting, by the computer device, an instance data to the conversational system in response to determining that the instance data in a data store storage matches the at least one search term in the query;

in response to determining that the at least one search term does not match the instance data in the data store, performing, by the computer device, a hybrid search of an external domain-specific knowledge source, the hybrid search comprising a radius approach, a similarity measure, and statistical information usage based on concept frequency to find relaxed data matches that are semantically related to the at least one search term in the query; and

generating, by the computer device, a response to the query based on contextual information and structural information based on the relaxed data matches found from the hybrid search.

18. The computer-implemented method according to claim 17 , wherein the plurality of criteria of semantically-related terms received by the computer device include a structural information obtained from the external domain-specific knowledge source, a contextual information obtained from the query, and information content of the query.