The elevators are the primary means of vertical transportation in most high-rise buildings and potentially can play a vital role in the event of an emergency, such as a fire. The dominant practice around the world, however, is to discourage the use of elevators during a fire. The major reason for this practice is the unpredictability of the condition of the emergency and the danger of entrapping passengers as well as rescue workers (e.g. firefighters) in the elevator. To safeguard the use of elevators in a fire emergency, the US National Institute of Standard and Technology (NIST) is working with the elevator industry to develop new elevators that function during fires. The new elevators are designed to be used both as a rescue vehicle, carrying firefighters to the site of the blaze, and as a secondary method (after stairwells) for evacuating building occupants. NIST is investigating software and sensing systems that can adapt to changing smoke and heat conditions so that the elevators can maintain safe and reliable operation during fire emergencies. Such changes could also allow elevators to be operated with remote control from the ground floor during fires, thus freeing urgently needed firefighters from elevator operation duties. NIST is also testing more reliable elevator-dedicated emergency power systems and waterproof elevator components to be used in the new generation of elevators. Besides hardware and software improvements, NIST also incorporates its expertise in virtual reality simulation into the making of the new elevators. Virtual reality simulations help test scenarios for coordinating firefighting activities, and for elevator and stairway evacuation. By including elevators into its graphic computer models, NIST will help fire safety experts identify the most effective operational procedures for specific fire conditions. Furthermore, NIST fire researchers hope to collaborate on emergency elevator operations standards with colleagues from around the world. Global standardization should reduce confusion during an emergency, enabling people to take evacuation actions with confidence. What does "Such changes" refer to in the second paragraph?