LRI Universit

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LRIUniversité Paris-Sud ORSAY

• Nicolas Spyratos
• Philippe Rigaux

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Université Paris-Sud

• One of the largest scientific Universities in
  France
• Five campuses
• Scientific campus located at Orsay (about 25 Kms
  south of Paris)
• 25 000 Students
• Over ten departments (physics, mathematics,
  computer science)

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Department of Computer Science

• 250 members (researchers, teachers)
• Currently offering 16 programs
• Two laboratories
• LRI (11 research groups)
• http//www.lri.fr
• LIMSI (8 research groups)
• Fundings Government, CNRS, European projects

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SeLeNe related activities

• Nicolas
• Databases
• Conceptual modeling
• Information integration
• Philippe
• Databases (including spatial DB)
• A strong practical experience in Web environments
  based on XML
• Nicolas Philippe document integration and
  restructuring

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Motivation

• In a nutshell collaborative production of
  e-Learning documents
• Some preliminary ideas
• Authors produce documents
• A system manages the set of documents
• Users create new documents by assembling/restructu
  ring existing ones
• A scenario based on a cooperative, distributed,
  e-learning system.
• and many questions

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Preliminary ideas authors

• Author content producer
• Uses his own structure and vocabulary
• Stores his documents in his own repository
• Author a conscious part of a collaborative
  system
• Provides a description of his documents to the
  system
• Commits to maintain an up-to-date and available
  version of each document

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Preliminary ideas the system

• The system enables cooperation between authors
• It knows the description provided by each author
• It can access (and possibly store locally) the
  documents
• The system acts as a mediator for users
• It defines a uniform view for all the documents
• It provides querying and restructuring services
  to create new documents

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Preliminary ideas the user

• The user publishes documents
• In a specific form (a book, a portal, a set of
  slides)
• Using specific choices for the content and the
  structure
• The user creates new (derived) documents by
• Extracting fragments from the documents managed
  by the system
• Authoring his own fragments, then integrating
  them with the extracted ones
• Materializing at will the result

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Keywords

• Content management
• How to structure (e-Learning) content and how to
  describe this structure
• Content integration
• How to provide a uniform view to query
  documents and extract fragments
• Deriving and restructuring document
• How to create new documents by assembling
  fragments of existing ones

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A simple scenario

• Three authors, A, B and C, cooperate to produce a
  course on database systems
• Author A produces content on data modeling
• An introduction to the topic
• Chapters on database design, the relational model
  and SQL
• Author B produces content on system aspects
• Database indexing
• Query processing and optimization

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Contents description

• Each author uses his own terminology to describe
  his documents
• A fragment is any identifiable subset of a
  document
• Any fragment must be indexed under some term.

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The system

• We assume a commonly agreed structure for the
  area of databases
• Each author must provide a mapping between his
  terminology and the systems terminology
• The system provides query facilities

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Deriving new documents

• Structure The user is free to choose the
  structure of the document he composes
• Composition Each fragment is
• Either directly provided by the user
• Or chosen from the answer to a query addressed to
  the system

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Query refinement

• A multi-step process
• Initial query shows all the relevant fragments
  known to the system
• Subsequent steps restrict the fragments to those
  considered as relevant to the user
• Ideally the refined query delivers exactly the
  relevant fragments and in the right order

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Example (user/teacher)

• Author C is now a teacher, creating an
  introduction to DB. It contains
• A general introduction (written by C)
• A query retrieving introduction written by A
• A query selecting fragments on database design
  (retrieved from As documents)
• An introduction to query processing, with queries
  retrieving figures from B documents.
• Questions assuming a query returns a set of
  fragments, how can we make a sub-selection

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Example (user/learner)

• Author C is now a learner. He will create a
  document summarizing the courses he is interested
  in, namely
• A query retrieving the general introduction to DB
  (written by C)
• His own annotations
• Several queries, whose results will be mixed with
  the annotations
• Questions how can we make queries
  user-friendly?
• E.g., as a path to the relevant fragment?
• Relying on metadata?

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Example personalized documents

• Author C is now a learner.
• The system knows the courses followed by C, maybe
  with other information (frequency, success,
  whatever) ? relates to knowledge
  trajectories?
• gt the system maintains and updates automatically
  the document summarizing the courses material
  ? instance of the learning trail concept?

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Questions

• Primitive versus derived documents (problem of
  cycles)?
• How can we select a subpart of a result set?
• Should we allow users to browse directly the
  sources?
• What is the granularity of documents?
• Is there a need for users views?
• Should we introduce replication of content, and
  how?