ANAPHORA RESOLUTION BASED ON LINGUISTIC TECHNOLOGIES
Disclosed are system, method and computer program product for creating syntactic-semantic structures of natural language sentences in natural language processing of a natural language text, comprising generating syntactic trees for each sentence including syntactic nodes and tree-like syntactic relations; generating semantic structure corresponding to the at least one syntactic tree; the at least one semantic structure includes semantic nodes corresponding to the plurality of syntactic nodes and tree-like semantic relations corresponding to the p tree-like syntactic relations; if a syntactic tree includes two different syntactic nodes corresponding to a single entity, connecting the semantic nodes corresponding to the syntactic nodes by a non-tree link.
1 . A method for creating syntactic-semantic structures of natural language sentences in natural language processing of a natural language text, comprising:
generating by a hardware processor at least one syntactic tree for each sentence including a plurality of syntactic nodes and a plurality of tree-like syntactic relations;
generating by a hardware processor at least one semantic structure corresponding to the at least one syntactic tree,
wherein the at least one semantic structure includes a plurality of semantic nodes corresponding to the plurality of syntactic nodes and a plurality of tree-like semantic relations corresponding to the plurality of tree-like syntactic relations;
if the at least one syntactic tree includes at least two different syntactic nodes corresponding to a single entity, then connecting the semantic nodes corresponding to the at least two different syntactic nodes by at least one non-tree link; and
performing by the hardware processor further natural language processing of the text using the semantic structure comprising the at least one non-tree link.
2 . The method of claim 1 , wherein the connecting of the semantic nodes by the at least one non-tree link comprises:
generating a plurality of possible non-tree links between the syntactic nodes;
calculating a rank for each possible non-tree link; and
selecting the possible non-tree links with the highest ranking.
3 . The method of claim 2 , wherein the calculating of the rank for each possible non-tree link between the semantic nodes uses similarity metric for corresponding entities according to their location in a semantic hierarchy.
4 . The method of claim 1 , wherein the at least two different syntactic nodes corresponding to a single entity belong to at least two different syntactic trees.
5 . The method of claim 1 , wherein the at least two different syntactic nodes include a controller node and a pronoun node controlled by the controller node;
wherein the determining that the controller node and the pronoun node correspond to a single entity includes accessing an anaphora rule for the pronoun node;
wherein the determining that the controller node and the pronoun node correspond to a single entity includes at least one of:
determining whether a syntactic tree path from the controller node to the pronoun node is among possible paths according to the rule;
determining whether at least one of properties of the controller node is possible according to the rule;
determining whether the controller node and the pronoun node are in grammatical agreement according to the rule;
determining whether the linear direction of a link between the controller node and the pronoun node is possible according to the rule;
determining whether a semantic node corresponding to the controller node and a semantic node corresponding to the pronoun node are semantically compatible;
determining whether a value of a non-tree link between the semantic node corresponding the controller node and the semantic node corresponding to the pronoun node is above a threshold value.
6 . The method of claim 1 , wherein the determining among the plurality of syntactic nodes the at least two different syntactic nodes corresponding to the single entity includes:
generating for the at least one syntactic tree different sets of non-tree links between at least some syntactic nodes of the plurality of syntactic nodes;
determining the rank of each set of non-tree links; and
determining that the syntactic nodes connected by the set of non-tree links with the highest rank correspond to a single entity.
7 . A system for creating syntactic-semantic structures of natural language sentences in natural language processing of a natural language text, the system comprising:
a syntactic analysis module configured to generate at least one syntactic tree for each sentence including a plurality of syntactic nodes and a plurality of tree-like syntactic relations;
a semantic analysis module configured:
to generate at least one semantic structure corresponding to the at least one syntactic tree,
wherein the at least one semantic structure includes a plurality of semantic nodes corresponding to the plurality of syntactic nodes and a plurality of tree-like semantic relations corresponding to the plurality of tree-like syntactic relations;
to determine if the at least one syntactic tree includes at least two different syntactic nodes corresponding to a single entity, and then to connect the semantic nodes corresponding to the at least two different syntactic nodes by at least one non-tree link; and
a natural language processing module for further natural language processing of the text using the semantic structure.
8 . The system of claim 7 , wherein the connecting of the semantic nodes by the at least one non-tree link comprises:
generating a plurality of possible non-tree links between the syntactic nodes;
calculating a rank for each possible non-tree link; and
selecting the possible non-tree links with the highest ranking.
9 . The system of claim 8 , wherein the calculating a rank for each possible non-tree link uses similarity metric for entities in a semantic hierarchy corresponding to the semantic nodes corresponding to the syntactic nodes.
10 . The system of claim 7 , wherein the at least two different syntactic nodes belong to at least two different syntactic trees.
11 . The system of claim 7 , wherein the at least two different syntactic nodes include a controller node and a pronoun node controlled by the controller node;
wherein the determining that the controller node and the pronoun node correspond to a single entity includes accessing an anaphora rule for the pronoun node;
wherein the determining that the controller node and the pronoun node correspond to a single entity includes at least one of:
determining whether a syntactic tree path from the controller node to the pronoun node is among possible paths according to the rule;
determining whether at least one of properties of the controller node is possible according to the rule;
determining whether the controller node and the pronoun node are in grammatical agreement according to the rule;
determining whether the linear direction of a link between the controller node and the pronoun node is possible according to the rule;
determining whether a semantic node corresponding to the controller node and a semantic node corresponding to the pronoun node are semantically compatible;
determining whether a value of a non-tree link between the semantic node corresponding the controller node and the semantic node corresponding to the pronoun node is above a threshold value.
12 . The system of claim 7 , wherein the determining among the plurality of syntactic nodes the at least two different syntactic nodes corresponding to the single entity includes:
generating for the at least one syntactic tree different sets of non-tree links between at least some syntactic nodes of the plurality of syntactic nodes;
determining the rank of each set of non-tree links; and
determining that the syntactic nodes connected by the set of non-tree links with the highest rank correspond to a single entity.
13 . A computer program product stored on a non-transitory computer-readable storage medium, the computer program product comprising computer-executable instructions for creating syntactic-semantic structures of natural language sentences in natural language processing of a natural language text, comprising instructions for:
generating by a hardware processor at least one syntactic tree for each sentence including a plurality of syntactic nodes and a plurality of tree-like syntactic relations;
generating by a hardware processor at least one semantic structure corresponding to the at least one syntactic tree,
wherein the at least one semantic structure includes a plurality of semantic nodes corresponding to the plurality of syntactic nodes and a plurality of tree-like semantic relations corresponding to the plurality of tree-like syntactic relations;
if the at least one syntactic tree includes at least two different syntactic nodes corresponding to a single entity, then connecting the semantic nodes corresponding to the at least two different syntactic nodes by at least one non-tree link; and
performing by the hardware processor further natural language processing of the text using the semantic structure.
14 . The computer program product of claim 13 , wherein the connecting of the semantic nodes by the at least one non-tree link comprises:
generating a plurality of possible non-tree links between the syntactic nodes;
calculating a rank for each possible non-tree link; and
selecting the possible non-tree links with the highest ranking.
15 . The computer program product of claim 14 , wherein the calculating a rank for each possible non-tree link uses similarity metric for entities in a semantic hierarchy corresponding to the semantic nodes corresponding to the syntactic nodes.
16 . The computer program product of claim 13 , wherein the at least two different syntactic nodes belong to at least two different syntactic trees.
17 . The computer program product of claim 13 , wherein the at least two different syntactic nodes include a controller node and a pronoun node controlled by the controller node;
wherein the determining that the controller node and the pronoun node correspond to a single entity includes accessing an anaphora rule for the pronoun node;
wherein the determining that the controller node and the pronoun node correspond to a single entity includes at least one of:
determining whether a syntactic tree path from the controller node to the pronoun node is among possible paths according to the rule;
determining whether at least one of properties of the controller node is possible according to the rule;
determining whether the controller node and the pronoun node are in grammatical agreement according to the rule;
determining whether the linear direction of a link between the controller node and the pronoun node is possible according to the rule;
determining whether a semantic node corresponding to the controller node and a semantic node corresponding to the pronoun node are semantically compatible;
determining whether a value of a non-tree link between the semantic node corresponding the controller node and the semantic node corresponding to the pronoun node is above a threshold value.
18 . The computer program product of claim 13 , wherein the determining among the plurality of syntactic nodes the at least two different syntactic nodes corresponding to the single entity includes:
generating for the at least one syntactic tree different sets of non-tree links between at least some syntactic nodes of the plurality of syntactic nodes;
determining the rank of each set of non-tree links; and
determining that the syntactic nodes connected by the set of non-tree links with the highest rank correspond to a single entity.