Position Indexing of Adjacent and Concurrent N-Grams for Polyphonic Music Retrieval

In this paper we examine the retrieval performance of adjacent and concurrent n-grams generated from polyphonic music data. We deploy a method to index polyphonic music using a word position indexer with the n-gram approach. Using all possible combinations of monophonic sequences from polyphonic music data, “overlaying” word locations within a document are obtained, such as needed with polyphony (i.e. where more than one word can assume the same word position). The feasibility in utilising the position information of polyphonic ‘musical words’ is investigated using various proximity-based and structured query operators available with text retrieval system. Our experiments show that nested phrase operators improve the retrieval performance and we present the results of our comparative study on a collection of 5456 polyphonic pieces encoded in the MIDI format.