Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage medium, to facilitate searching indexed resources associated with sort key values. In one aspect, a method includes actions of maintaining an index including a respective index entry for each of multiple resources, wherein each index entry includes a first sort key that is associated with a corresponding sort key value, receiving a query from a user device, obtaining, based on query features, a first restrict criterion that includes one or more binary value bits, determining, based on (i) the first restrict criterion and (ii) the first sort key, a first count of index entries that are each associated with a respective resource that is responsive to the query, and in response to determining that the first count of index entries satisfies the predetermined threshold, obtaining a set of index entries corresponding to resources related to the query.

Abstract: A hybrid-sharded index includes document-sharded posting lists and term-sharded posting lists. Implementations include systems and methods for updating a hybrid-sharded index. For example, a method may include receiving updates to the hybrid-sharded index and generating, at a first leaf node, replacement posting lists and change information for a respective second leaf node. The method may also include dividing the replacement posting lists into portions, a portion having associated change information and being associated with a respective one of the second leaf nodes and sending the portions to respective leaf nodes. At a particular leaf node of the second leaf nodes, the method includes merging a received portion into an updated posing list portion, swapping the updated posting list portion into memory. During the swap, the change information and the updated posting list portion are used to respond to a query with an older version of the hybrid-sharded index.

Abstract: A hybrid-sharded index includes document-sharded posting lists and term-sharded posting lists. Implementations include systems and methods using a distributed hybrid-sharded index. For example, a method may include receiving, at a root node, a query having a first term and a second term and determining, that the first term is term-sharded. The method may also include retrieving a term-sharded posting list for the first term from a first leaf node that stores the term-sharded posting list and determining, at the root node, a second leaf node that stores a document-sharded posting list for the second term. The method may include sending the second term and a sub-set of documents from the term-sharded posting list to the second leaf node, the sub-set being documents assigned to the second leaf node; and generating a search result using a response received from the second leaf node.

Abstract: The present invention provides a method and a system for automatic keyword extraction based on supervised or unsupervised machine learning techniques. Novel linguistically-motivated machine learning features are introduced, including discourse comprehension features based on construction integration theory, numeric features making use of syntactic part-of-speech patterns, and probabilistic features based on analysis of online encyclopedia annotations. The improved keyword extraction methods are combined with word sense disambiguation into a system for automatically generating annotations to enrich text with links to encyclopedic knowledge.

Abstract: The present invention provides a method and a system for automatic keyword extraction based on supervised or unsupervised machine learning techniques. Novel linguistically-motivated machine learning features are introduced, including discourse comprehension features based on construction integration theory, numeric features making use of syntactic part-of-speech patterns, and probabilistic features based on analysis of online encyclopedia annotations. The improved keyword extraction methods are combined with word sense disambiguation into a system for automatically generating annotations to enrich text with links to encyclopedic knowledge.