A framework for querying a database for structural information on 3D images of macromolecules: A Web-based query-by-content prototype on the BioImagemacromolecular server

Nowadays we are experiencing a remarkable growth in the number of databases that have become accessible over the Web. However, in a certain number of cases, for example, in the case of BioImage, this information is not of a t extual nature, thus posing new challenges in the design of tools to handle these data. In this work, are concentrate on the development of new mechani sms aimed at "querying" these databases of complex data sets by their intri nsic content, rather than by their textual annotations only. We concentrate our efforts on a subset of BioImage containing 3D images (volumes) of biol ogical macromolecules, implementing a first prototype of a "query-by-conten t" system. In the context of databases of complex data types the term query -by-content makes reference to those data modeling techniques in which user -defined functions aim at "understanding" (to some extent) the informationa l content of the data sets. In these systems the matching criteria introduc ed by the user are related to intrinsic features concerning the 3D images t hemselves, hence, complementing traditional queries by textual key words on ly. Efficient computational algorithms are required in order to "extract" s tructural information of the 3D images prior to storing them in the databas e. Also, easy-to-use interfaces should be implemented in order to obtain fe edback from the expert. Our query-by-content prototype is used to construct a concrete query, making use of basic structural features, which are then evaluated over a set of three-dimensional images of biological macromolecul es. This experimental implementation can be accessed via the Web at the Bio Image server in Madrid, at http://www.bioimage.org/qbc/index.html. (C) 1999 Academic Press.