Dynamic Partitioning of Signature Files

The signature file access method has proved to be a convenient indexing technique, in particular for text data. Because in can deal with unformatted data, many application domains nave shown interest in signarure file techniques, e.g. office information systems, statistical and logic databases. We argue that multimedia databases should also take advantage of this method, provided convenient storage structures for organizing signarure files are available. Our main concern here is the dynamic organization of signarures based on a partitioning paradigm called Quick Filter. A signature file is partitioned by a hasning function and the partitions are organized by linear hashing. Thorough performance evaluation of the new scheme is provided, and it is compared with single-level and multi-level storage structures. Results show that quick filter is economical in space and very convenient for applications dealing with large files of dynarnic data. and where user queries result in signatures with high weights. These characteristics are panicularly interesting for multimedia databases, where integrated access to attributes, text and images must be provided.