Patent ID: 8041721

Claim:
An attribute extraction method executable by a machine operatively connected to an archival memory and a work memory, the archival memory storing documents, registration dates thereof and attributes thereof, said method comprising: extracting, vis-a-vis a plurality of documents in the archival memory that have registration dates falling within a desired time period, feature words for each attribute value of corresponding attributes of the plurality of documents; registering, into said work memory, said desired time period, and said extracted feature words for said each attribute value of the corresponding attributes of the plurality of documents; determining, amongst the extracted feature words in said work memory, first feature words for which an attribute has a first attribute value and second feature words for which said attribute has a second attribute value; calculating a similarity between said first feature words and said second feature words; identifying, a single unit time as said desired time period in case of absence of successive unit time periods in which a value of similarity between said first feature words is greater than or equal to a threshold value and adjacent unit time period in which a value of similarity between said first feature words is greater than or equal to the threshold value; judging, based on the step of the identifying, whether the similarity satisfies a condition; and outputting said second attribute value when said similarity satisfies the condition.