Abstract
Standard database approaches to querying information on the Web
focus on the source(s) and provide a query language based on a given predefined
organization (schema) of the data: this is the source-driven
approach.
However, can the Web be seen as a standard database? There is
no super-user in charge of monitoring the source(s) (the data is constantly
updated), there is no homogeneous structure (no common
explicit structure thus), the Web itself never stops growing, etc.
For these reasons, we believe
that the source-driven standard approach is not suitable to the Web.
As an alternative, we propose a user-oriented approach based on the idea that the schema is a posteriori expressed by the user's needs when asking a query. Given a user query, AKIRA (Agentive Knowledge-based Information Retrieval Architecture) extracts a target structure (structure expressed in the query) and uses standard information retrieval and filtering techniques to access potentially relevant documents.
The user-oriented paradigm means that the structure through which the data is viewed does not come from the source but is extracted from the user query. When a user asks a query, the relevant information is retrieved from the Web and stored as is in a cache. Then the information is extracted from the raw data using computational linguistic techniques. The AKIRA cache (smart-cache) represents these extracted layers of meta-information on top of the raw data. The smart-cache is an object-oriented database whose schema is inferred from the user's target structure. It is designed on demand through a library of concepts that can be assembled together to match concepts and meta-concepts required in the user's query. The smart cache can be seen as a view of the Web.
To the best of our knowledge, AKIRA is the only system that uses information retrieval and extraction integrated with database techniques to provide maximum flexibility to the user and offer transparent access to the content of Web documents.