Hierarchical Encapsulation and Connection in a Graphical User Interface: a Music Case Study

Graphical representations consisting of nodes and arcs have proven useful in many interactive applications. However, as the number of nodes and arcs becomes large, viewing, editing and understanding the network becomes problematic and the value of the representation breaks down. We combat this problem by providing the user the ability to hierarchically structure the network by encapsulating related nodes into modules. Hierarchical structuring allows the user to collapse portions of the network into viewable and understandable sized chunks. This reduces the apparent complexity of the network in a manner similar to top-down structuring in programming; a top level view gives a concise representation of the network devoid of unnecessary details. As you descend the hierarchy, details about the internal structure of modules are revealed. The intent of this thesis is to explore the use of hierarchical encapsulation by means of a case study. Our case study is a system for controlling the routing of audio and control signals among devices in an audio studio. Nodes in our network are audio devices and the arcs are the paths that interconnect them. This thesis illustrates the value of user-control over structuring of the network, level and type of representation. The results have ~pplicability in other applications and these are discussed along with general principles learned in the course of the case study.