On-the-fly scheduling as a manifestation of partial-order planning and dynamic task values

Abstract

Objective: The aim of this study was to develop a computational account of the spontaneous task ordering that occurs within jobs as work unfolds ("on-the-fly task scheduling"). Background: Air traffic control is an example of work in which operators have to schedule their tasks as a partially predictable work flow emerges. To date, little attention has been paid to such on-the-fly scheduling situations. Method: We present a series of discrete-event models fit to conflict resolution decision data collected from experienced controllers operating in a highfidelity simulation. Results: Our simulations reveal air traffic controllers' scheduling decisions as examples of the partialorder planning approach of Hayes-Roth and Hayes- Roth. The most successful model uses opportunistic first-come-first-served scheduling to select tasks from a queue. Tasks with short deadlines are executed immediately. Tasks with long deadlines are evaluated to assess whether they need to be executed immediately or deferred. Conclusion: On-the-fly task scheduling is computationally tractable despite its surface complexity and understandable as an example of both the partial-order planning strategy and the dynamic-value approach to prioritization. Copyright © 2014, Human Factors and Ergonomics Society.