Abstraction Mechanisms in Support of Top-Down and Bottom-Up Task Specification

Abstraction is a powerful mechanism for describing objects and relationships from multiple, yet consistent, perspectives. When properly applied to interface design, abstraction mechanisms can provide the interaction flexibility and simplicity so desperately needed and demanded by today's diverse user community. Fundamental to achieving such goals has been the integration of visual programming techniques with a unique blend of abstraction mechanisms to support user interaction and task specification. The research presented in this paper describes crucial abstraction mechanisms employed within the Taskmaster environment to support top-down and bottom-up task specification. In particular, this paper (a) provides an overview of the Taskmaster environment, (b) describes top-down specification based on multi-level, menu-driven interaction and (c) describes bottom-up specification based on cutset identification and pseudo-tool concepts.