Real-time human interaction with supervised learning algorithms for music composition and performance (2011)

This thesis examines machine learning through the lens of human-computer interaction in order to address fundamental questions surrounding the application of machine learning to real-life problems, including: Can we make machine learning algorithms more usable and useful? Can we better understand the real-world consequences of algorithm choices and user interface designs for end-user machine learning? How can human interaction play a role in enabling users to efficiently create useful machine learning systems, in enabling successful application of algorithms by machine learning novices, and in ultimately making it possible in practice to apply machine learning to new problems? 
The scope of the research presented here is the application of supervised learning algorithms to contemporary computer music composition and performance. Computer music is a domain rich with computational problems requiring the modeling of complex phenomena, the construction of real-time interactive systems, and the support of human creativity. Though varied, many of these problems may be addressed using machine learning techniques, including supervised learning in particular. This work endeavors to gain a deeper knowledge of the human factors surrounding the application of supervised learning to these types of problems, to make supervised learning algorithms more usable by musicians, and to study how supervised learning can function as a creative tool. 
This thesis presents a general-purpose software system for applying standard supervised learning algorithms in music and other real-time problem domains. This system, called the Wekinator, supports human interaction throughout the entire supervised learning process, including the generation of training examples and the application of trained models to real-time inputs. The Wekinator is published as a freely-available, open source software project, and several composers have already employed it in the creation of new musical instruments and compositions. 
This thesis also presents work utilizing the Wekinator to study human-computer interaction with supervised learning in computer music. Research is presented which includes a participatory design process with practicing composers, pedagogical use with non-expert users in an undergraduate classroom, a study of the design of a gesture recognition system for a sensor-augmented cello bow, and case studies with three composers who have used the system in completed artistic works. 
The primary contributions of this work include (1) a new software tool allowing real-time human interaction with supervised learning algorithms, which includes a novel “playalong” interaction for generating training data in real-time; (2) a demonstration of the important roles that interaction|encompassing both human-computer control and computer-human feedback|can play in the development of supervised learning systems, and a greater understanding of the differences between interactive and conventional machine learning contexts; (3) a better understanding of the requirements and challenges in the analysis and design of algorithms and interfaces for interactive supervised learning in real-time and creative problem domains; (4) a clearer characterization of composers' goals and priorities for interacting with computers in music composition and instrument design; and (5) a demonstration of the usefulness of interactive supervised learning as a creativity support tool. This work both empowers musicians to create new forms of art and contributes to a broader HCI perspective on machine learning practice.