Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for generating a catalog for multiple datasets, the method comprising accessing multiple extant data sets, the extant data sets including data sets that are independently generated and structurally dissimilar; organizing the data sets into collections, each data set in each collection belonging to the collection based on collection data associated with the data set; for each collection of data sets: determining, from a subset of the data sets that belong to the collection, metadata that describe the data sets that belong to the collection, wherein the metadata does not include the collection data, and attributing, to other data sets in the collection, the metadata determined from the subset of data sets; and generating, from the collections of data sets and the determined metadata, a catalog for the multiple datasets.

Abstract: Systems, methods, and computer-readable media are provided for searching a tabular database. According to certain embodiments, search parameters for searching a tabular database are received from a user device and a row of a tabular database that corresponds to the search parameters is determined. In certain embodiments, the row may be determined by comparing the search parameters with a plurality of stored exemplar search queries, each of the plurality of stored exemplar search queries comprising a search query associated with a row and a column of the tabular database. A column of the tabular database that corresponds to the search parameters is determined by comparing the search parameters with the plurality of stored exemplar search queries. In certain embodiments, at least one cell of the tabular database is determined. The determined cell may be located at the intersection of the determined row and the determined column.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for generating an ontology of entity attributes. One of the methods includes extracting a plurality of attributes based upon a plurality of queries; and constructing an ontology based upon the plurality of attributes and a plurality of entity classes.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for generating a catalog for multiple datasets, the method comprising accessing multiple extant data sets, the extant data sets including data sets that are independently generated and structurally dissimilar; organizing the data sets into collections, each data set in each collection belonging to the collection based on collection data associated with the data set; for each collection of data sets: determining, from a subset of the data sets that belong to the collection, metadata that describe the data sets that belong to the collection, wherein the metadata does not include the collection data, and attributing, to other data sets in the collection, the metadata determined from the subset of data sets; and generating, from the collections of data sets and the determined metadata, a catalog for the multiple datasets.

Abstract: Systems and techniques are provided for generating a union table with from stitchable tables. Tables may be extracted from web pages to obtain extracted tables. Stitchable tables may be determined from the extracted tables. Hidden attributes for the stitchable tables may be extracted from the web pages from which the stitchable tables were extracted using segmentation of text for contextual data from the web pages into segment sequences, and alignment of the segment sequences. Iterative pairwise alignment may be used to align the segment sequences and obtain aligned segments. The stitchable tables may be joined into a union table. Hidden attributes from the aligned segments may be added to the union table. Headers for the hidden attributes in the union table may be labeled using a database of entities and class labels.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for extracting facts from a collection of documents. One of the methods includes obtaining a plurality of seed facts; generating a plurality of patterns from the seed facts, wherein each of the plurality of patterns is a dependency pattern generated from a dependency parse; applying the patterns to documents in a collection of documents to extract a plurality of candidate additional facts from the collection of documents; and selecting one or more additional facts from the plurality of candidate additional facts.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for clustering query refinements. One method includes building a representation of a graph for a first query, wherein the graph has a node for the first query, a node for each of a plurality of refinements for the first query, and a node for each document in the document sets of the refinements, and wherein the graph has edges from the first query node to each of the refinement nodes, edges from the first query to each document in the respective document set of the first query, edges from each refinement to each document in the respective document set of the refinement, and edges from each refinement to each co-occurring query of the refinement. The method further includes clustering the refinements into refinement clusters by partitioning the refinement nodes in the graph into proper subsets.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for clustering query refinements. One method includes building a representation of a graph for a first query, wherein the graph has a node for the first query, a node for each of a plurality of refinements for the first query, and a node for each document in the document sets of the refinements, and wherein the graph has edges from the first query node to each of the refinement nodes, edges from the first query to each document in the respective document set of the first query, edges from each refinement to each document in the respective document set of the refinement, and edges from each refinement to each co-occurring query of the refinement. The method further includes clustering the refinements into refinement clusters by partitioning the refinement nodes in the graph into proper subsets.

Abstract: Systems, methods, and computer-readable media are provided for searching a tabular database. According to certain embodiments, search parameters for searching a tabular database are received from a user device and a row of a tabular database that corresponds to the search parameters is determined. In certain embodiments, the row may be determined by comparing the search parameters with a plurality of stored exemplar search queries, each of the plurality of stored exemplar search queries comprising a search query associated with a row and a column of the tabular database. A column of the tabular database that corresponds to the search parameters is determined by comparing the search parameters with the plurality of stored exemplar search queries. In certain embodiments, at least one cell of the tabular database is determined. The determined cell may be located at the intersection of the determined row and the determined column.

Abstract: Methods, systems, and apparatus, including computer program products, for generating aspects associated with entities. In some implementations, a method includes receiving data identifying an entity; generating a group of candidate aspects for the entity; modifying the group of candidate aspects to generate a group of modified candidate aspects comprising combining similar candidate aspects and grouping candidate aspects using one or more aspect classes each associated with one or more candidate aspects; ranking one or more modified candidate aspects in the group of modified candidate aspects based on a diversity score and a popularity score; and storing an association between one or more highest ranked modified candidate aspects and the entity. The aspects can be used to organize and present search results in response to queries for the entity.

Abstract: Methods, systems, and apparatus, including computer program products, for generating aspects associated with entities. In some implementations, a method includes receiving data identifying an entity; generating a group of candidate aspects for the entity; modifying the group of candidate aspects to generate a group of modified candidate aspects comprising combining similar candidate aspects and grouping candidate aspects using one or more aspect classes each associated with one or more candidate aspects; ranking one or more modified candidate aspects in the group of modified candidate aspects based on a diversity score and a popularity score; and storing an association between one or more highest ranked modified candidate aspects and the entity. The aspects can be used to organize and present search results in response to queries for the entity.

Abstract: Systems and techniques are provided for receiving an input column and a search keyword and providing one or more suggested columns with which to merge the input column. A coverage score and a refinity score are calculated for potential columns based on the input column as well as a search score based on the search keyword. The one or more suggested columns may be determined based on the coverage score, refinity score, and/or the search score. The input column and/or a potential column may be modified based on a function and the modification may result in a plurality of modified input and/or potential columns. Coverage, refinity, and search scores may be calculated based on the modified columns.

Abstract: Methods, systems, and apparatus, including computer program products, for generating aspects associated with entities. In some implementations, a method includes receiving data identifying an entity; generating a group of candidate aspects for the entity; modifying the group of candidate aspects to generate a group of modified candidate aspects comprising combining similar candidate aspects and grouping candidate aspects using one or more aspect classes each associated with one or more candidate aspects; ranking one or more modified candidate aspects in the group of modified candidate aspects based on a diversity score and a popularity score; and storing an association between one or more highest ranked modified candidate aspects and the entity. The aspects can be used to organize and present search results in response to queries for the entity.