A study on adjajency measures for reassembling text files

Recovery of fragmented files relies on the ability to accurately evaluate the adjacency of two fragments. Text-based files typically organize data in a very weakly structured manner; therefore, fragment reassembly remains a challenging task. In this work, we evaluate existing adjacency measures that can be used for assembling fragmented test files. Our results show that individual performances of existing measures are far from adequately addressing this need. We then introduce a new approach that attempts to exploit the limited structural characteristics of text files which utilize constructs for description, presentation, and processing of file data. Our approach builds a statistical model of the ordering of file-type specific constructs and incorporates this information into adjacency measures for more reliable fragment reassembly. Results show that reassembly accuracy increases significantly with this approach.