Transcript Nicolas and Phillipe`s slides on SeLeNe

LRI
Université Paris-Sud ORSAY
Nicolas Spyratos
Philippe Rigaux
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…)
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
SeLeNe related activities

Nicolas




Philippe



Databases
Conceptual modeling
Information integration
Databases (including spatial DB)
A strong practical experience in Web environments
based on XML
Nicolas + Philippe : document integration and
restructuring
Motivation

In a nutshell: collaborative production of [e-

Some preliminary ideas …
Learning] documents





Authors produce documents
A system manages the set of documents
Users create new documents by
assembling/restructuring existing ones
A scenario based on a cooperative,
distributed, e-learning system.
… and many questions
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
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
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
Keywords

Content management


Content integration


How to structure (e-Learning) content and how to
describe this structure
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
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
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.
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
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
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
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 A’s 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 subselection
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 “userfriendly”?


E.g., as a “path” to the relevant fragment?
Relying on “metadata”?
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”?
=> the system maintains and updates
automatically the document summarizing the
course’s material
 instance of the “learning trail” concept?
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 user’s views?
Should we introduce replication of content,
and how?