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Schema Matching and Data Extraction over HTML Tables

Schema Matching and Data Extraction over HTML Tables. Cui Tao Data Extraction Research Group Department of Computer Science Brigham Young University. supported by NSF. Introduction. Many tables on the Web How to integrate data stored in different tables? Detect the table of interest

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Schema Matching and Data Extraction over HTML Tables

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  1. Schema Matching and Data Extraction over HTML Tables Cui Tao Data Extraction Research Group Department of Computer Science Brigham Young University supported by NSF

  2. Introduction • Many tables on the Web • How to integrate data stored in different tables? • Detect the table of interest • Form attribute-value pairs (adjust if necessary) • Do extraction • Infer mappings from extraction patterns

  3. ? ProblemDetecting The Table of Interest

  4. Problem Different schemas • Different source table schemas • {Run #, Yr, Make, Model, Tran, Color, Dr} • {Make, Model, Year, Colour, Price, Auto, Air Cond., AM/FM, CD} • {Vehicle, Distance, Price, Mileage} • {Year, Make, Model, Trim, Invoice/Retail, Engine, Fuel Economy} • Target database schema {Car, Year, Make, Model, Mileage, Price, PhoneNr}, {Car, Feature}

  5. ProblemAttribute is Value

  6. ? ? Problem Attribute-Value is Value

  7. ProblemValue is not Value

  8. ProblemFactored Values

  9. ProblemSplit Values

  10. ProblemMerged Values

  11. Table extending over several pages Single-Column Table (formatted as list) ProblemInformation Behind Links

  12. Solution • Detect the table of interest • Form attribute-value pairs (adjust if necessary) • Do extraction • Infer mappings from extraction patterns

  13. SolutionDetect The Table of Interest • ‘Real’ table test • Same number of values • Table size • Attribute test • Density measure test # of ontology extracted values total # of values in the table

  14. 2001 2001 2001 2000 2000 2000 2000 2000 2000 1999 1999 Solution Remove Factoring

  15. SolutionReplace Boolean Values

  16. SolutionForm Attribute-Value Pairs <Make, Honda>, <Model, Civic EX>, <Year, 1995>, <Colour, White>, <Price, $6300>, <Auto, Auto>, <Air Cond., Air Cond.>, <AM/FM, AM/FM>

  17. SolutionAdjust Attribute-Value Pairs <Make, Honda>, <Model, Civic EX>, <Year, 1995>, <Colour, White>, <Price, $6300>, <Auto, Auto>, <Air Cond., Air Cond.>, <AM/FM, AM/FM>

  18. Unstructured and semi-structured: concatenate < Single attribute value pairs: Pair them together <Price, $7,988>, <Mileage, 63,168 miles>, <Body Type, Car>, <Body Style, 4 DR Sedan>, <Transmission, Automatic>, <Engine, 3.0 L V-6>, <Doors, 4>, <Fuel Type, Gas>, <Stock Number, 22764>, <VIN, 1FAFP52U2WA139879> List: Mark the beginning and the end > SolutionAdd Information Hidden Behind Links

  19. SolutionInferred Mapping Creation {Car, Year, Make, Model, Mileage, Price, PhoneNr}, {Car, Feature}

  20. Each row is a car. SolutionInferred Mapping Creation {Car, Year, Make, Model, Mileage, Price, PhoneNr}, {Car, Feature}

  21. SolutionInferred Mapping Creation {Car, Year, Make, Model, Mileage, Price, PhoneNr}, {Car, Feature}

  22. SolutionInferred Mapping Creation {Car, Year, Make, Model, Mileage, Price, PhoneNr}, {Car, Feature}

  23. SolutionInferred Mapping Creation {Car, Year, Make, Model, Mileage, Price, PhoneNr}, {Car, Feature}

  24. SolutionInferred Mapping Creation {Car, Year, Make, Model, Mileage, Price, PhoneNr}, {Car, Feature}

  25. SolutionInferred Mapping Creation {Car, Year, Make, Model, Mileage, Price, PhoneNr}, {Car, Feature}

  26. Experimental Results Car Advertisement Application domain • 10 “training” tables • 100% of the 57 mappings (no false mappings) • 94.6% precision of the values in linked pages (5.4% false declarations) • 50 test tables • 94.7% of the 300 mappings (no false mappings) • On the bases of sampling 3,000 values in linked pages, we obtained 97% recall and 86% precision

  27. Other Applications • Cell Phone Plan Application domain • Soccer Player Application domain

  28. Contribution • Provides an approach to extract information automatically from HTML tables • Suggests a different way to solve the problem of schema matching

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