Business Process Simulation: Probabilistic Modeling of Intermittent Resource Availability and Multitasking Behavior

TL;DR

This paper presents a probabilistic modeling approach for business process simulation that captures intermittent resource availability and variable multitasking behavior, improving the realism of process simulations.

Contribution

It introduces algorithms to discover probabilistic calendars and multitasking capacities from event logs, addressing limitations of existing deterministic models.

Findings

Probabilistic models better replicate activity distributions.

Enhanced simulation accuracy for cycle times.

Models capture variability in resource availability and multitasking.

Abstract

In business process simulation, resource availability is typically modeled by assigning a calendar to each resource, e.g., Monday-Friday, 9:00-18:00. Resources are assumed to be always available during each time slot in their availability calendar. This assumption often becomes invalid due to interruptions, breaks, or time-sharing across processes. In other words, existing approaches fail to capture intermittent availability. Another limitation of existing approaches is that they either do not consider multitasking behavior, or if they do, they assume that resources always multitask (up to a maximum capacity) whenever available. However, studies have shown that the multitasking patterns vary across days. This paper introduces a probabilistic approach to model resource availability and multitasking behavior for business process simulation. In this approach, each time slot in a resource calendar has an associated availability probability and a multitasking probability per multitasking level. For example, a resource may be available on Fridays between 14:00-15:00 with 90\% probability, and given that they are performing one task during this slot, they may take on a second concurrent task with 60\% probability. We propose algorithms to discover probabilistic calendars and probabilistic multitasking capacities from event logs. An evaluation shows that, with these enhancements, simulation models discovered from event logs better replicate the distribution of activities and cycle times, relative to approaches with crisp calendars and monotasking assumptions.