Measuring and Optimizing Durability against Scheduling Disturbances

Abstract

Flexibility is a useful and common metric for measuring the amount of slack in a Simple Temporal Network (STN) solution space. We extend this concept to specific schedules within an STN’s solution space, developing a related notion of durability that captures an individual schedule’s ability to withstand disturbances and still remain valid. We identify practical sources of scheduling disturbances that motivate the need for durable schedules, and create a geometricallyinspired empirical model that enables testing a given schedule’s ability to withstand these disturbances. We develop a number of durability metrics and use these to characterize and compute specific schedules that we expect to have high durability. Using our model of disturbances, we show that our durability metrics strongly predict a schedule’s resilience to practical scheduling disturbances. We also demonstrate that the schedules we identify as having high durability are up to three times more resilient to disturbances than an arbitrarily chosen schedule is.