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Using Transportation Distances for Measuring Melodic Similarity. Pichaya Tappayuthpijarn Qiang Wang. Outline. Introduction Melodic Similarity Measuring The Earth Mover’s Distance (EMD) The Proportional Transportation Distance (PTD) Results & Conclusion. Introduction.
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Using Transportation Distances for Measuring Melodic Similarity Pichaya Tappayuthpijarn Qiang Wang
Outline • Introduction • Melodic Similarity Measuring • The Earth Mover’s Distance (EMD) • The Proportional Transportation Distance (PTD) • Results & Conclusion
Introduction • Weighted notes are well suited to represent music. • Measuring melodic similarity by comparing weighted notes. • Using EMD or PTD to measure the similarity.
Melodic Similarity Measuring • Weighted Notes represented by (Time, Pitch, Weight). The weights only reflect the note durations.
Properties of a Metric **For pseudo-metric, only properties i, iii and iv holds.
The Earth Mover’s Distance (EMD) • measures the minimum amount of work needed to transform one into the other by moving weight.
Minimize the overall cost with constraints
The Proportional Transportation Distance (PTD) EMD v.s. PTD • PTD is a modified version of EMD. • In the case of unequal total weight, triangle inequality does not hold for the EMD. • By PTD, triangle inequality holds, making database search more efficient by using indices.
The Proportional Transportation Distance • for both point set, divide every point’s weight by its point set’s total weight • then calculate the EMD for the resulting point sets.
Properties of PTD • A pseudo-metric. Triangle inequality holds true a+b>=c
Gives clear distinction of groups. The fact that the EMD allows partial matching, while the PTD matches all notes, leads to a clear distinction of these groups by the PTD, but not the EMD.
Can recognize augmented versions of the same melody as similar.
Result & Conclusion • PTD leads to the identification of about 3.9% of 100 randomly chosen search ( for r = 1). • For r = 5, we need less than 1000 calculations instead of 476,000. • PTD Indexing reduces the query running time.