A model of human approach to describing algorithms using diagrams

A model of the human approach to describing algorithms is developed by analyzing algorithm descriptions by humans using pen and paper. The authors consider algorithms which are described by drawing data objects on paper and demonstrating a sequence of actions on the data. The model formalizes the abstractness, visibility, and referenceability of objects in the workspace; the `natural´ ways of deterministically and nondeterministically selecting objects; and a wide range of actions for manipulating objects including conditional, condition-based repetition, and parallel actions. The steps of an algorithm for finding a minimum spanning tree are formalized in the proposed model