Phdaey

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Phdaey

  1. 1. Data Dependency Management inHeterogeneous and Dynamic DIS Giorgio Orsi orsi@elet.polimi.it Ph. Day June 26th 2008 Politecnico di Milano Dipartimento di Elettronica e Informazione
  2. 2. Motivations• Heterogeneous, Independent, Dynamic and Mobile Data Sources. • Heterogeneity of models and technologies. • Systems designed independently. • Real world is not static and changes rapidly. • Users and data sources move and the engineer cannot follow them all the day to solve their problems.• We need on-the-fly, integrated access to relevant information. PHDAY 08
  3. 3. Ontologies at rescue Possible Solution: Domain Ontology Ontology-Based Context-aware Data Integration AccessData Source CA-DL MappingsOntologies Data Sources PHDAY 08
  4. 4. Tasks and ChallengesTasks:• (User-driven) Automatic Schema Extraction (ROSEX).• (User-driven) Lightweight Automatic Data Integration (X-SOM).• Cross-Model, Distributed Query processing (SPARQL-Explorer).• Context-Aware Data Filtering (CADD Tool).Challenges:• Cognitive support to HD-DIS modeling (What you see is what you get).• On-the-fly tailoring of relevant data and smart caching (What you get is what you need).• Technology gaps: Mobile devices, data streams, sensor networks. PHDAY 08
  5. 5. ToolsExtraction:• Focus on really used data models (e.g., relational, XML, RDF) and Natural Language.• Output: ontological representations of the data sources.• Data structures obtained through reverse engineering of best practices in design or through data-mining.Data Integration:• Current solutions (DL-Lite, El++) are almost theoretical solutions and are far from being real systems (Kripke frames are not user-friendly).• Keep the data where they currently are, use ontologies to get them out!• Use data dependencies to optimize query plans.Data Tailoring:• Satisfy all the constraints is nor practical nor really needed.• The system/user context determines the subset of constraints and data to be considered. PHDAY 08
  6. 6. And now... Questions ( where: ~□(question => answer) ) PHDAY 08

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