節奏複雜度在自動作曲之應用與研究

Abstract

本論文為節奏複雜度的分析研究，以求節奏複雜度在自動作曲上之應用，有別於一般自動作曲的探討，將重心放在節奏上。首先探討各種節奏複雜度定義，針對四種常見的節奏複雜度分析與比較，除了一般古典樂常見的節奏外，並延伸其定義在不同拍號以及不規則節奏上，以適應自由靈活的自動作曲，以實例分析四種複雜度的表現，找出最適合運用在自動作曲上的節奏複雜度定義。另外，在本文中提出了以節奏複雜度為基礎的節奏產生方法，以現有的節奏複雜度定義延伸，特別是針對不同拍號以及不規則節奏的產生。最後將節奏複雜度分析與節奏產生系統結合，實作出以節奏複雜度為基礎的自動作曲系統，將現有的樂曲在不更動音高的狀況下改編節奏，產生出單旋律的樂曲，並以實驗評估系統的效能，進一步討論節奏複雜度與音樂結構的關係，以及兩者之間的交互影響。希望透過本研究，讓自動作曲的節奏產生有更多的可能性，配合上其他演算法，使自動作曲更臻完備。

In this thesis, we provide a study on rhythm generator in order to apply it to automated composition. We focus the study on rhythm which is distinct from common study of automated composition. First, we discuss the various definition of rhythm complexity, and analyze and compare four common definitions of rhythm complexity in order to find the most suitable for automated composition. Besides the common rhythm in classical music, we take various time signatures and irrational rhythms at the examples to compare four rhythm complexity definitions. Furthermore, we bring up an idea for rhythm generator based on rhythm complexity which can be applied for generating rhythm of various time signatures and irrational rhythm. Last but not least, we implement an automated composition system based on rhythm complexity which combines analysis of rhythm complexity and rhythm generator. Through the experiment, we verify the system and discuss the relationship between rhythm complexity and music structure. We hope this study can be applied to other algorithm in order to create a better system of automated composition.