Semantic Web Queries

by

Mark Vickers

Funded by NSF

2

Introduction

Web Queries Traditional Web

Uses keyword matching Returns superfluous information

Semantic Web Uses semantic matching Returns only pertinent information

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Background

What is the Semantic Web? Provides machines “understandable” data Provides answers rather than pages Ontologies provide foundation for understanding

“A shared, explicitly defined, generic conceptualization” [Gruber 93]

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Extraction Ontology

Value Expression: \s*[$]\s*(\d{1,3})*(\.\d{2})?

Key Words: Price, Cost, Fare

Left Context: Price, Cost, Fare

Right Context: Purchase, Book, Buy

Exception Expression: *\.\d{3,*}

Lexicon File: none

Data Frame:

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Find the Ontology“Tell me about cruises on San Francisco Bay. I’d like to

know scheduled times, cost, and the duration of cruises on Friday of next week.”

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Find the Ontology“Tell me about cruises on San Francisco Bay. I’d like to

know scheduled times, cost, and the duration of cruises on Friday of next week.”

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Formulate Query

Friday, Oct. 29thcost

duration

Selection Constants

San Francisco Bayscheduled times

Projection Join Path

= Result ( )

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StartTime Price Duration Source

10:45 am, 12:00 pm, 1:15, 2:30, 4:00 $20.00, $16.00, $12.00

1

10:00 am, 10:45 am, 11:15 am, 12:00 pm, 12:30 pm, 1:15 pm, 1:45 pm, 2:30 pm, 3:00 pm, 3:45 pm, 4:15 pm, 5:00 pm

$17.00, $16.00, $12.00

1 Hour 2

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Contributions

English Web queries without NLP Web queries based on semantics Returning answers rather than pages Semantic Web application