NDLI: Harvesting relational tables from lists on the web

Content Provider	Springer Nature Link
Author	Elmeleegy, Hazem Madhavan, Jayant Halevy, Alon
Copyright Year	2011
Abstract	A large number of web pages contain data structured in the form of “lists”. Many such lists can be further split into multi-column tables, which can then be used in more semantically meaningful tasks. However, harvesting relational tables from such lists can be a challenging task. The lists are manually generated and hence need not have well-defined templates—they have inconsistent delimiters (if any) and often have missing information. We propose a novel technique for extracting tables from lists. The technique is domain independent and operates in a fully unsupervised manner. We first use multiple sources of information to split individual lines into multiple fields and then, compare the splits across multiple lines to identify and fix incorrect splits and bad alignments. In particular, we exploit a corpus of HTML tables, also extracted from the web, to identify likely fields and good alignments. For each extracted table, we compute an extraction score that reflects our confidence in the table’s quality. We conducted an extensive experimental study using both real web lists and lists derived from tables on the web. The experiments demonstrate the ability of our technique to extract tables with high accuracy. In addition, we applied our technique on a large sample of about 100,000 lists crawled from the web. The analysis of the extracted tables has led us to believe that there are likely to be tens of millions of useful and query-able relational tables extractable from lists on the web.
Starting Page	209
Ending Page	226
Page Count	18
File Format	PDF
ISSN	10668888
Journal	The VLDB Journal
Volume Number	20
Issue Number	2
e-ISSN	0949877X
Language	English
Publisher	Springer-Verlag
Publisher Date	2011-03-02
Publisher Place	Berlin, Heidelberg
Access Restriction	One Nation One Subscription (ONOS)
Subject Keyword	Structured data on the web Table extraction List segmentation WebTables ListExtract Database Management
Content Type	Text
Resource Type	Article
Subject	Information Systems Hardware and Architecture

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1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
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