Abstract: Determining one or more concepts associated with a query is disclosed. A query is received. A list of concepts and associated scores is received. The concepts fit within a concept hierarchy. A density function is used to evaluate the received concepts. One or more concepts are associated with the query based at least in part on the results of the density function.

Abstract: Methods, systems, and apparatus for resolving ambiguous queries. A search query is received and metrics are identified for the query that are associated with respective categories. Each metric indicates a user preference for search results that are responsive to the query and associated with the metric's respective category. The identified metrics are used to determine whether the query is ambiguous. Responsive to determining that the query is ambiguous, the identified metrics are used to determine a user preference for one or more categories of search results responsive to the ambiguous query. Search results associated with the one or more user preferred categories are ranked higher than search results that are not associated with the one or more user preferred categories.

Abstract: Determining one or more concepts associated with a query is disclosed. A query is received. A list of concepts and associated scores is received. The concepts fit within a concept hierarchy. A density function is used to evaluate the received concepts. One or more concepts are associated with the query based at least in part on the results of the density function.

Abstract: Determining one or more concepts associated with a query is disclosed. A query is received. A list of concepts and associated scores is received. The concepts fit within a concept hierarchy. A density function is used to evaluate the received concepts. One or more concepts are associated with the query based at least in part on the results of the density function.

Abstract: Determining one or more concepts associated with a query is disclosed. A query is received. A list of concepts and associated scores is received. The concepts fit within a concept hierarchy. A density function is used to evaluate the received concepts. One or more concepts are associated with the query based at least in part on the results of the density function.

Abstract: Determining one or more concepts associated with a query is disclosed. A query is received. A list of concepts and associated scores is received. The concepts fit within a concept hierarchy. A density function is used to evaluate the received concepts. One or more concepts are associated with the query based at least in part on the results of the density function.

Abstract: A method of combining information from multiple heterogeneous workers comprises transmitting a first search request to a search worker to assist the search worker in searching a first database and returning a first results set. A second search request is directed to a peer worker to assist the peer worker in initiating a search of a second database across a network asynchronously from the search worker and returning a second results set. The first results set and second results set are then incorporated into a composite results set.

Abstract: A method of ranking search results includes producing a relevance score for a document in view of a query. A similarity score is calculated for the query utilizing a feature vector that characterizes attributes and query words associated with the document. A rank value is assigned to the document based upon the relevance score and the similarity score.

Abstract: A method of ranking search results includes producing a relevance score for a document in view of a query. A similarity score is calculated for the query utilizing a feature vector that characterizes attributes and query words associated with the document. A rank value is assigned to the document based upon the relevance score and the similarity score.