Question answering system, data search method, and computer program

A data search method comprising:

• selecting a feature word from an input question;
• generating a transformational question in which the feature word is replaced with another word;
• executing a first search process based on the transformational question generated;
• selecting a word included in a first search result acquired by executing the first search process as an extension word;
• executing a second search process with using the selected extension word;
• analyzing a correspondence relation among extension words included in a second search result acquired by executing the second search process;
• determining the feature word and a constructive part of an answer equivalent word in the second search result based on an analysis result;
• selecting a word determined to be an answer;
• and
• displaying the selected word.

A computer program stored in a computer readable medium, the computer program causing a computer to execute a data search process comprising:

• selecting a feature word from an input question;
• generating a transformational question in which the feature word is replaced with another word;
• executing a first search process based on the transformational question generated;
• selecting a word included in a first search result acquired by executing the first search process as an extension word;
• executing a second search process with using the selected extension word;
• analyzing a correspondence relation among extension words included in a second search result acquired by executing the second search process;
• determining the feature word and a constructive part of an answer equivalent word in the second search result based on an analysis result;
• and
• selecting a word determined to be an answer.