Agent-based modeling (ABM) has gained great popularity in recent years, especially in application areas where human behavior is important, because it opens up the possibility of capturing such behavior in great detail. Hybrid models which combine ABM with discrete-event simulation (DES) are particularly appealing in service industry applications. However in this paper we argue that many of the so-called distinctions between agents in an ABM and entities in a DES are artificial, and we describe several DES models which use standard entities to represent agent-like behaviors.
In March 2010, the UK Operational Research Society Simulation Workshop SW10 included a panel discussion entitled ‘Discrete-event simulation is dead, long live agent-based simulation!’. This discussion was subsequently published in the Journal of Simulation (Siebers et al. 2010), and there was a similar panel discussion, extended to cross-paradigm modelling, at the 2011 Winter Simulation Conference (Heath et al., 2011).
Within the mainstream Operations Research community, there has undoubtedly been much interest in recent years in the use of agent-based modeling (ABM). The motivation for the present paper originates from a second paper in the Journal of Simulation (Brailsford 2014), written in response to Siebers et al (2010), in which I argue – admittedly as a devil’s advocate – that many of the cited benefits of agent-based modeling can be achieved through the use of a traditional DES approach. In the current paper, I argue that many of the distinctions between agents in an ABM and entities in a DES are artificial, and that many hybrid models which use both ABM and DES could equally well just use one or the other. Moreover, these hybrid models could be more easily developed in a single paradigm. These arguments are illustrated by several examples where DES has been used successfully to tackle ‘ABM-type’ problems.
The paper assumes that the reader is reasonably familiar with the basics of both ABM and DES. The latter can be taken for granted for the WSC readership, but readers who require an introduction to ABM are referred to Macal and North (2010).