Querying Heterogeneous Datasets on the Linked Data Web

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Querying Heterogeneous Datasets on the Linked Data Web:

Challenges, Approaches, and Trends

André Freitas, Edward Curry, João G. Oliveira, Seán O’Riain


IEEE Internet Computing

http://doi.ieeecomputersociety.org/10.1109/MIC.2011.141http://andrefreitas.org

A. Freitas, E. Curry, J. G. Oliveira, and S. O’Riain,“Querying Heterogeneous Datasets on the Linked Data Web: Challenges, Approaches, and Trends,” IEEE ��Internet Computing, vol. 16, no. 1, pp. 24-33, 2012.


Motivation


Querying Data over the Web

We can see (a) natural language query over two search engines; (b) corresponding SPARQL representation; and (c) semantic gap between the user’s information needs and data representation.


Expressivity-Usability Trade-Off

Expressivity–usability trade-off for querying over structured data. Blue dots indicate an ideal query mechanism for linked data must provide both

high expressivity and high usability


Challenges


Challenges

Analysis focuses on investigation of existing approaches under the perspective of the usability-expressivity trade-off.

This focus guides the categorization and analysis of existing challenges, approaches and trends.


Challenge Dimensions

Query Expressivity Ability to query datasets by referencing

elements in data model structure, as well as to operate over the data (aggregate results, express conditional statements, etc.)

Usability Easy-to-operate, intuitive, and task-efficient

query interface Vocabulary-level Semantic Matching

Ability to semantically match user query terms to dataset vocabulary-level terms


Challenge Dimensions

Entity Reconciliation Matches entities expressed in the query to

semantically equivalent dataset entities Semantic Tractability

Ability to answer queries not supported by explicit dataset statements

– For example, “Is Natalie Portman an Actress?” can be supported by the statement “Natalie Portman starred Star Wars,” instead of an explicit statement “Natalie Portman occupation Actress,” which might not be present in dataset


Approaches


Approaches

Information Retrieval approaches Entity-centric search Structure search

Natural Language approaches Question Answering Semantic best-effort natural language interfaces


Entity-Centric Search

e.g. Sindice


Structure Search

e.g. Semplore


Question Answering

e.g. FreyA


Semantic Best-Effort/NL

e.g. Treo


Comparative Analysis (Approaches)


Trends


Addressing the Challenges

The functionality analysis of existing approaches provides insights on how the major challenges should be addressed.

This set of strategic functionalities define the set of trends.


Linked Data Web


Trends

Complementary Search and Query Services User Interaction and Feedback Mechanisms Semantic Best-Effort Query Model Natural Language Processing Techniques Distributional Semantic Model External Knowledge Sources for Semantic Enrichment Integrated Entity Reconciliation Techniques


IEEE Internet Computing

http://doi.ieeecomputersociety.org/10.1109/MIC.2011.141http://andrefreitas.org

A. Freitas, E. Curry, J. G. Oliveira, and S. O’Riain,“Querying Heterogeneous Datasets on the Linked Data Web: Challenges, Approaches, and Trends,” IEEE ��Internet Computing, vol. 16, no. 1, pp. 24-33, 2012.


Further Reading

A. Freitas, E. Curry, J. G. Oliveira, and S. O’Riain, A Distributional Structured Semantic Space for Querying RDF Graph Data, International Journal of Semantic Computing, vol. 5, no. 4, pp. 433-462, 201

S. O’Riain, E. Curry, and A. Harth, XBRL and Open Data for Global Financial Ecosystems: A Linked Data Approach, International Journal of Accounting Information Systems, vol. 13, no. 2, pp. 141-162, 2012.

A. Freitas, E. Curry, and S. O'Riain, �A Distributional Approach for Terminology-Level Semantic Search on the Linked Data Web, in 27th ACM Symposium On Applied Computing (SAC 2012), 2012.

A. Freitas, J. G. Oliveira, S. O'Riain, and E. Curry, �A Multidimensional Semantic Space for Data Model Independent Queries over RDF Data, in Fifth IEEE International Conference on Semantic Computing (ICSC 2011)

A. Freitas, T. Knap, S. O’Riain, and E. Curry, W3P: Building an OPM based provenance model for the Web, Future Generation Computer Systems, vol. 27, no. 6, pp. 766-774, Jun. 2011.

Querying Heterogeneous Datasets on the Linked Data Web

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