Patent ID: 8930373
Filing Date: 2015-01-06
Classification: G06F

Abstract:
1. A search system for performing a phrase search, the search system comprising: a processor; a token division unit configured to divide an input character string to be searched into a plurality of tokens; a token position definition unit configured to set each token to be excluded in an occurrence position calculation as an exclusion token and to set each token to be included in the occurrence position calculation as a headword token, and to define an occurrence position for each headword token; a position offset information assigning unit configured to assign, to each of the exclusion tokens, position information obtained with the headword token followed by the exclusion tokens and to assign the headword token followed by the exclusion tokens as a starting point; and an indexing processing unit configured to perform indexing on the plurality of tokens such that whether or not the exclusion tokens follow one of the plurality of tokens is identifiable, wherein index data including the occurrence position to be assigned to each headword token, position information to be assigned to each of the exclusion tokens, and additional information for identifying whether or not the exclusion tokens follow one of the plurality of tokens; a search processing unit configured to extract, based on a search process considering exclusion tokens being requested in response to a phrase search query containing a search token string, a token string that matches the search token string not only in constituent tokens but also in occurrence positions and position information of the constituent tokens, with reference to the index data; a determination unit configured to determine whether or not a search process considering exclusion tokens is requested based on a setting of the phrase search query; and a changing unit configured to change, based on the search token string of the phrase search query including a token string that has been registered to be searched in consideration of exclusion tokens in a phrase search, a search process to be performed into a search process considering exclusion tokens regarding the registered token string, and wherein the search processing unit is configured to apply a first weight to an extracted token string that matches the search token string in the constituent tokens, the occurrence positions, and the position information, and the search processing unit is configured to apply a second weight to a token string that matches the search token string contained in the phrase search query in constituent headword tokens and occurrence positions of the constituent headword tokens and does not match the search token string in a concatenation relationship with one of the exclusion tokens.