Structure Determines Assignment Strategies in Diagrammatic Production Scheduling

Abstract

The article discusses an application of the Representational Epistemology (REEP) approach to the development of a graphical interface for production planning and scheduling called ROLLOUT. The paper reports two studies conducted with bakery planning and scheduling professionals that focus on the cognitive support provided by ROLLOUT in reasoning about the spatial-temporal structure of production processes. The results of the first task suggest that given tabular representations, participants frequently make errors in decisions about the assignment of production sequences in terms of their temporal structure. The errors are more frequent for problems that require reasoning about consequences backwards rather than forwards in time. The second task evaluated participants’ performance at improving production schedules on ROLLOUT. Log files revealed that participants improved the temporal efficiency of the schedule by making edit operations involving frequent repetitions with the same instances that tended to change the time and not the order of production. The authors propose that participants were able to effectively use ROLLOUT to generate an efficient schedule at increasing levels of precision by using the representation to test out and re-evaluate concurrent what-if scenarios. The advantages of ROLLOUT for such tasks are explained in terms of (1) the presence of diagrammatic constraints that preserve domain relations, (2) the presence of a global interpretive scheme, and (3) the degree of meaningful conceptual interrelations available in the representation.