Information search device and information search method using topic-centric query routing

Claim 1

An information search device for selecting a search engine, comprising: a relevant term collector for collecting, from web pages having links pointing to topic search engines and from topic search engine pages, a relevant term that describes a topic and/or content that is handled by each search engine; an index generator for producing a search engine selection index from said collected relevant terms; a search engine selection index storage unit for storing said search engine selection index; a query expansion unit for obtaining an expanded term that is relevant to a search keyword submitted by a user to a general purpose search engine; an expanded term storage unit for storing the expanded term obtained by said query expansion unit; and an engine selector for calculating goodness-of-fit between said search keyword and each search engine based on information that is stored in said search engine selection index storage unit and said expanded term storage unit, and for selecting, based on said goodness-of-fit, a search engine that is relevant to said search keyword, wherein said goodness-of-fit is calculated by F   ( E i , G c ) = ∑ k = 1 q   ∑ g = 1 k   W ik * C cg * f   ( S ic , X cg ) where f(x,y) is a function that is 1 when character strings x and y are equal and 0 when character strings x and y are not equal, E i are search engines, G c are groups comprising search keywords associated with a topic, W ik are degrees of importance, C cg are frequencies of occurrence, s ik are relevant terms, and x cg are expanded terms.