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Research Interests

  • Database Systems: relational, deductive, object-oriented, and hierarchical ( not what you think!).
  • Query Languages and Query Optimization.
  • Data Analysis: multi-dimensional databases, data warehousing, OLAP, data mining.
  • Information Integration: multi-database systems, interoperability, schema integration and evolution.
  • Newer Data Models: social networks, semi-structured data, data on the web, XML.
  • Networks: social networks, LDAP network directories, network data management.
  • Logic Programming: extensions, semantics, and optimization; application for data cleaning.
  • Higher-Order Logics and Advanced Database Models.
  • Uncertainty in Data Modeling and Deduction.
  • Personalization and Social Web: recommender systems, social networks and media.

Research Story:

As the world we live in is getting more and more networked, the need to understand, manage, and harness the data on the web is becoming critical. While data in traditional databases tends to be highly structured, with a clear notion of schema, data on the web is loosely structured (also called semi-structured), or worse, unstructured, and is often not accompained by any clear notion of schema. What does it mean to query this data? What do you look for when you mine this data? If there are several data sources containing related information, how do you combine the information in them to answer queries involving them all? How can you index such data for efficient storage and retrieval? What do you do when the data you want to analyze is not stored some place but is streaming through? My research has been concerned with addressing these questions. I am also interested in newer applications which challenge the foundations and technology of databases.

More recently, I am interested in integrating the paradigms of database-style querying, IR-style search, and RecSys-style recommendations. And I want to do this taking user's context into account. Context as in the social neighborhood of the user as well as context as in the user's current information needs or her current task. Opinions and "intelligence" of the crowd is something to be naturally harnessed in this setting. Stay tuned for more information on what drives my research these days.

Current Projects:

  • Query Processing by, for, and of the Masses: Putting the User in the Loop (funded by NSERC)
  • Business Intelligence (funded by an NSERC Strategic Grant on Business Intelligence Network, in cooperation with top universities in Canada and leading industries including IBM/Cognos and SAP/Business Objects):
    • Analyzing Influential Behavior in Very Large Social Networks (with Francesco Bonchi and Amit Goyal)
    • Data Cleaning Using Integrity Constraints (with Leo Bertossi and Solmaz Kolahi)
    • Keyword Oriented Online Analytical Processing (KOOLAP) (with Mohammad Tajer)
    • Building Taxonomies from Documents and Social Media (with Ali Moosavi and Rachel Pottinger)
    • Data Cleaning in Data Warehouses (with Leo Bertossi)
  • Social Networks Structure Analysis (with Chen Grief and Pooya Esfandiar)
  • Privacy-preserving data mining (with Shaofeng Bu and Raymond Ng)

Past Projects: