6/97 mechanical engineering: input output

input/output

Virtual SWAT Team to the Rescue

By Greg Paula

Although the dramatic rescue of hostages in the Japanese ambassador's residence in Lima, Peru, in April was generally applauded throughout the world, some law-enforcement experts have argued that the mission was also a partial failure: One hostage and two soldiers were killed, and 25 hostages were wounded. The top job of law enforcement in such situations, according to officers, is to save every hostage's life, subdue terrorists, and bring criminals in alive so that they can be judged in a court of law.

In the space of minutes or even seconds, officers on rapid-response missions must distinguish terrorists from hostages, sort out surrendering criminals from those who are still dangerous, and protect both the hostages and any innocent bystanders. Their duties may also include identifying the wounded and ensuring that medical personnel can perform triage and save lives. And no one can forget the necessity of protecting the officers' own lives.

VRaptor may look like an advanced computer game, but its aim is deadly serious: training police officers to save others' lives and their own in real-world assaults on hostage takers

Preserving life and liberty in such situations is a thankless job, but thanks to training that uses virtual reality (VR), it no longer has to be an impossible one. Through such training, police officers may acquire decision-making skills that, until now, could be learned only in the heat of a crisis.

The use of VR in training isn't new, of course; it's already been used to train staff who must decommission nuclear facilities, for instance. The breakthrough that may help save lives in rapid-response missions of the future is the development of dynamic VR-based scenarios--situations that change significantly with each training session or even within a session.

The key is a set of simulation components that can be assembled like building blocks to support the just-in-time development of simulated training scenarios. Developed by researchers at Sandia National Laboratories in Albuquerque, N.M., under the Laboratory Directed Research and Development Program, these building blocks--including reusable human models, behaviors, and application-specific simulation modules--are used to create tools that train law-enforcement officials to engage in rapid-response missions.

The software, developed by Sandia, runs on graphics workstations from Silicon Graphics Inc. in Mountain View, Calif. The resulting system, called VRaptor, "enables any number of users, devices, and simulation modules to be networked to create a shared virtual world," said Sharon Stansfield, a computer scientist at Sandia and the project leader. "Each simulation module executes at its own speed without degrading the performance of other modules or time-critical updates of users' views."

In a VRaptor session, trainees must enter a closed structure by breaking through a wall or door, throw a concussion grenade to stun the people inside, enter the room, and bring out the hostages and any terrorists who have surrendered. Typically, the trainees must subdue terrorists almost instantly without shooting the hostages--or being shot themselves.

The true breakthrough has been Sandia researchers' creation of tools for customizing generic VR scenarios so that they expose trainees to perhaps the most-significant threats to life in rapid-response missions: the unpredictable. The aim of training is to help the rescuers make "shoot/no-shoot" decisions. But to do so effectively, each scenario must change. "Otherwise," Stansfield said, "rescuers' response will be a learned response to a specific situation, not a decision based on the unique situation at hand." Accordingly, VRaptor makes it easy for trainers to create scenarios with ever-changing variables, such as the positions of the terrorists and hostages in the room as well as how they will behave after the operation is under way.

Movie metaphors are used to describe the scenario's components: the director, the set, virtual actors, and scripts. "Marks" are provided to position each actor, who can be sitting, standing, facing forward, and so on. Virtual terrorists may put their hands behind their heads or fall to the floor to indicate their surrender; when virtual participants are shot by the trainee, they fall and die. Rescuers who do not return terrorists' fire also die. Aspects of these behaviors can be changed on the fly during a scenario to make it as realistic as possible.

VRaptor is still a prototype system. "Now that we've proven its viability, we'd like to see it developed further to address even more complex scenarios," Stansfield said, "such as bringing in medics to perform triage or learning to perform in hazardous environments like chemically or biologically contaminated areas." By providing such lifelike training, VRaptor promises to save the lives of hostages, police officers, and even terrorists.