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Explore the concepts of Linked Data, RDF Dumps, and SPARQL Endpoints for efficient data retrieval on the Semantic Web. Learn how to access, utilize, and benefit from structured data online.
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RDF Dump, Linked Data, and SPARQL EndPoints CS - 6V81 University of Texas at Dallas November 30, 2009 Presented by- Rohit Sharma
Agenda!!! • Preview? • Linked Data? • Access Linked Data? • RDF Dump? • SPARQL Endpoints? • Conclusion? • References? http://stuff.ratjed.com/our%20children.gif
Preview ? • Web standards : RDF and SPARQL • Logical Choice • Structured Data Online • Self Describing Nature of RDF • Enables agent to understand the relationship between entities • Also the nature of the entities themselves
Linked Data? • Tim Berners-Lee outlined four principles of Linked Data : • Use URIs to identify things. • Use HTTP URIs so that these things can be referred to and looked up ("dereference") by people and user agents. • Provide useful information (i.e., a structured description — metadata) • Include links to other, related URIs in the exposed data
Linked Data? Components of Linked Data : • URIs • HTTP • Resource Description Framework (RDF) • Serialization formats (RDFa, RDF/XML, N3, Turtle, and others)
Linked Data? “A term used to describe a recommended best practice for exposing, sharing, and connecting pieces of data, information, and knowledge on the Semantic Web using URIs and RDF.” One Example please?
Linked Data? Example: “How pyramidal neurons does their work with signal transducer to optimize the obesity?”
Linked Data? 0 RESULTS
Linked Data? Example? “How pyramidal neurons does their work with signal transducer to optimize the obesity?”
Linked Data? 282 Thousands hits , 0 Result
Linked Data? Linked Health Care Data : 32 Hits , 32 Results
Accessing Linked Data? • Data on the Semantic Web can be made available and consumed in many ways • RDF Dumps • RDF dumps of a dataset can be provided in 3 formats • RDF/XML • N-Triples • N-Quads • SPARQL Endpoints
RDF Dumps? • Common format for providing RDF data • It is just files of RDF/XML data (that conforms to the linked data tenets of Berners-Lee) • Works well with large amount of RDF data
RDF Dumps? • The RDF dump is a collection of files • Amassed by the Open Directory Project • These files are publicly and freely available • Download it from “http://rdf.dmoz.org/”.
SPARQL Endpoints? • A SPARQL endpoint is a conformant SPARQL protocol service • Defined in the SPROT(SPARQL Protocol for RDF) specification • USE? • A SPARQL endpoint enables users (human or other) to query a knowledge base via the SPARQL language • Maintaining a separate SPARQL endpoint for each data source makes it easier than a data warehouse approach for handling data updates
SPARQL Endpoints? • The results of Query are typically returned in one or more machine-processable formats • MORE? • a SPARQL endpoint is mostly conceived as a machine-friendly interface towards a knowledge base. • Both the formulation of the queries and the human-readable presentation of the results should typically be implemented by the calling software, and not be done manually by human users.
SPARQL Endpoints? • What does “EndPoint” means? • An EndPoint indicates a specific location for accessing a WebServiceusing a specific protocol and data format. • An association between a fully-specified InterfaceBinding and a network address, specified by a URI • That may be used to communicate with an instance of a Web Service
SPARQL EndPoints? Example: A SPARQL endpoint is any URL on the Web that implements the SPARQL protocol. If the URL http://example.com/sparql is a SPARQL endpoint, then we can send queries to it by issuing requests to a URL that looks like: http://example.com/sparql?query=SELECT+%3Fname+WHERE.... Note that the query itself is passed to the endpoint as a URL-encoded string.
Conclusion: • For simple query use SPARQL Endpoints. • For executing a large number of queries use RDF dump and run them locally. • Downloading a dump instead of fetching each URI/URL of a Linked Data is better • Reduces consumption of networking and computing resources • World: more connected & less confused. http://blog.nanoraid.com/0909email.jpg
References: • http://utdallas.bncollege.com/wcsstore/ExtendedSitesCatalogAssetStore/813_81302_1_33145.htm • http://rdf.dmoz.org/ • http://www.w3.org/2007/03/RdfRDB/papers/tummarello.pdf http://en.wikipedia.org/wiki/Semantic_Web_Services • http://www.cartoon/teen/church/light.gif • http://www.ted.com/index.php/talks/tim_berners_lee_on_the_next_web.html • http://www4.wiwiss.fu-berlin.de/pubby/ • http://www.semanticuniverse.com/sparql-example-part-i-•-q-lee-feigenbaum.html
Rohit Sharma rxs069100@utdallas.edu Contact: