Civil security activities are an essential aspect of stability operations that address threats and reduce violence to establish a safe environment in which civilians can freely move about and carry on normal activities. When addressing threats to civil security a military force must balance the use of nonlethal and lethal force in a way that best meets mission objectives. However, civilians may respond in unexpected ways to varying uses of force, making this balance difficult to achieve.

Researchers at the Naval Postgraduate School’s Center for Modeling Human Behavior have developed the agent-based simulation Workbench for Refining Rules of Engagement against Crowd Hostiles (WRENCH) to address this challenge. WRENCH models a security force carrying out civil security activities, addressing any emerging threats via the use of both nonlethal and lethal weapons. WRENCH also models realistic complexities of civilian individuals and groups that drive crowd behaviors and responses to the use of force. In WRENCH many aspects of the security force are user-specified, as well as the selection of the set of available weapons and the specification of tactical rules of engagement to govern weapons use. Many aspects of the civilian population are also controllable.

In this paper we first provide a brief overview of WRENCH’s design and capabilities in the context of securing an urban area and compound and describe key output metrics of interest. We then present an experiment that explores the effects of the use of different types of weapons under different sample rules of engagement across several different civilian scenarios. And finally, we discuss insights from both the experiment results analysis and the challenges associated with model design and validation efforts.

Keywords
AGENT-BASED SIMULATION

Additional Keywords
Stability operations, human behavior modeling, civil security