Collision of constrained work spaces: a uniform concept for design interactions

Since participants in a design process are almost separated in time (in addition to the usual separation in space), databases are an ideal medium to support and control their interaction. The basic premise of the paper is that each design artifact can be represented as a design object which occupies a certain domain in an n-dimensional work space which includes time in order to reflect the design stage during which certain design decisions are valid. The central hypothesis of the paper is that various kinds of interaction among designers (such as detecting the effects of decisions by other designers and responding to them by, e.g., performing corrections or retracing older states in order to resume work from there, and such as detecting that their own decisions may affect either designers and reacting to them by explicit notification of changes to other individuals) can all be explained by the same concept of work space collision. Constraints associated with the work spaces can be used to arbitrate between the conflicts in the colliding work spaces. The idea is applied to a variety of interaction forms to demonstrate its validity.