Implicit Structures for Pen-Based Systems Within a Freeform Interaction Paradigm

Tom Moran, Xerox Parc

Seminar on People, Computers, and Design
Stanford University March 17, 1995


Computer systems impose formal sets of concepts on their users. In many situations, such as intellectual and collaborative work, systems are almost always too formal and thus inhibit the very processes they are designed to support. An important fundamental problem for human-computer interaction design is how to "deformalize" systems. Pen-based drawing systems are one emerging class of "freeform" systems attempting to do this. But these systems, having traded power for freedom, give little support to even the most minimal structure in the material created with them.

This talk describes a scheme for extending an informal, pen-based whiteboard system (Tivoli on the Xerox LiveBoard) to provide a structured editing capability without violating its free expression and ease of use. The scheme supports list, text, table, and outline structures over handwritten scribbles and typed text. The scheme is based on the system temporarily perceiving the "implicit structure" that humans see in the material, which is called a WYPIWYG (What You Perceive Is What You Get) capability. The design techniques, principles, trade-offs, and limitations of the scheme will be discussed.


Tom Moran is a Principal Scientist and Manager of the Collaborative Systems Area at the Xerox PARC. He is also the Editor (and founder) of the journal Human-Computer Interaction. History: B.Architecture, University of Detroit; Ph.D., Computer Science, Carnegie-Mellon University; joined PARC in 1974; first Director, Rank Xerox EuroPARC, Cambridge, England (1986-90). Work: early work on the theoretical foundations of HCI with Stu Card and Allen Newell, resulting in the book "The Psychology of Human-Computer Interaction" (1983); developed several HCI analysis tools, including the Command Language Grammar, the external-internal task mapping, analysis of mental models, the QOC design rationale representation; designed and developed (with many others) several novel interactive systems, including the NoteCards idea-processing hypertext system, the Instructional Design Environment, the user-tailorable Buttons system, the RAVE media space environment, and the Tivoli electronic whiteboard system.


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