LRIUniversité Paris-Sud ORSAY

Nicolas SpyratosPhilippe 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

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

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/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

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

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 sub-selection

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”?

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?