APPARATUS AND METHOD FOR PERFORMING ADAPTIVE SIMILARITY SEARCHING IN A SEQUENCE DATABASE

An apparatus and method includes segmenting each sequence to be stored in a database into nonoverlapping or minimally overlapping subsequences with equal length. Each subsequence is then normalized using a normalization procedure (such as normalized with respect to the energy or maximum amplitude of each sequence) and transformed into a series of coefficients in a feature space. The search is based on hierarchical correlation in the feature space between the target sequence with the subsequences. The correlation between the target sequence and the stored sequences is performed first at the lowest level in the hierarchy. At any given level, a match is declared when the correlated result is larger than a specific threshold. Sequences that fail to satisfy the matching criterion are discarded. The process is continued at the following level until the highest level is reached. Because of the hierarchical search, linear scan of the entire sequence can be avoided.