Abstract: A method and system are provided of merging results in distributed information retrieval. A search manager is in communication with a plurality of components, wherein a component is a search engine working on a document collection and returning results in the form of a list of documents to a search query. The search manager submits a query to the plurality of components, receives results from each component in the form of a list of documents; estimates the success of a component in handling the query to generate a merit score for a component per query; applies the merit score to the results for the component; and merges results from the plurality of components by ranking in order of the applied merit score.

Abstract: A method and system for analyzing a document set (202, 420) are provided. The method includes determining a set of terms (312) from the terms of the document set that minimizes a distance measurement (405) from the given set of documents (420). The method includes using a greedy algorithm to build the set of terms incrementally, at each stage finding a single word that is closest to the document set (202, 420). The set of terms is evaluated to assess the ability to find the document set (202, 420). The set of terms are compared with expected terms to evaluate the ability to find the document set (202, 420). A measure of the ability to find a document set (202, 420) is provided by computing a distance measure (403) between a document set and an entire collection.

Abstract: An apparatus for searching a document collection is provided.

Abstract: A query difficulty prediction unit includes a query difficulty predictor to determine the extent of overlap between query documents received from a search engine operating on an input query and sub-query documents received from the search engine operating on sub-queries of the input query. The unit generates a query difficulty prediction from the extent of overlap.

Abstract: A method for searching a document collection includes providing an index of terms indicating the documents in which the terms appear. A first statistical distribution of each of at least some of the terms in the index and a second statistical distribution of each of at least some of the categories are estimated a over the documents in the collection. A query including one or more of the terms and a category restriction referring to at least one of the categories is accepted. A modified term distribution is produced by operating on the first statistical distribution of at least one of the terms in the query using the second statistical distribution, responsively to the category restriction. The query is applied to the index to return a response, in which occurrences of the at least one of the terms are scored responsively to the modified term distribution.

Abstract: A method and system for analyzing a document set (202, 420) are provided. The method includes determining a set of terms (312) from the terms of the document set that minimizes a distance measurement (405) from the given set of documents (420). The method includes using a greedy algorithm to build the set of terms incrementally, at each stage finding a single word that is closest to the document set (202, 420). The set of terms is evaluated to assess the ability to find the document set (202, 420). The set of terms are compared with expected terms to evaluate the ability to find the document set (202, 420). A measure of the ability to find a document set (202, 420) is provided by computing a distance measure (403) between a document set and an entire collection.

Abstract: A method and system for the detection of missing content in a searchable repository is provided. A system includes: a missing content query identifier (401) for identifying queries to a search engine (102) for which no or little relevant content is returned; a missing content detector (110) which clusters missing content queries by topic; and an output provider for providing details of a missing content topic.

Abstract: A method and system are provided of merging results in distributed information retrieval. A search manager (104) is in communication with a plurality of components, wherein a component is a search engine (106-108) working on a document collection and returning results in the form of a list of documents to a search query. The search manager (104) submits a query (202) to the plurality of components, receives results (213) from each component in the form of a list of documents; estimates (208) the success of a component in handling the query to generate a merit score (210) for a component per query; applies (220) the merit score (210) to the results for the component; and merges (222) results from the plurality of components by ranking in order of the applied merit score.

Abstract: A method for searching a document collection includes providing an index of terms indicating the documents in which the terms appear. A first statistical distribution of each of at least some of the terms in the index and a second statistical distribution of each of at least some of the categories are estimated a over the documents in the collection. A query including one or more of the terms and a category restriction referring to at least one of the categories is accepted. A modified term distribution is produced by operating on the first estimated statistical distribution of at least one of the terms in the query using the second estimated statistical distribution of the at least one of the categories, responsively to the category restriction. The query is applied to the index so as to return a response, in which occurrences of the at least one of the terms are scored responsively to the modified term distribution.

Abstract: A method and system for assessing the quality of one or more search engines are provided. The method and system monitor reformulation sessions by users (201) of a search engine (308, 402, 403) by retrieving data from a query log (307, 407, 408), wherein a reformulation session is a series of at least two queries to a search engine (308) issued by a user (201) to satisfy a single information need. The method and system then determine a reformulation session parameter for the search engine (308, 402, 403) and analyse the reformulation session parameter. The reformulation session parameter may be a rate of query reformulations in a reformulation session or a reformulation session duration. Analysing the reformulation session parameter for a single search engine may determine if the parameter changes with time or may determine the parameter with different settings in a single search engine.