This article says “Hitachi Ltd. today announced its release of the industry’s first AirLocation II Tag-w, a WiFi active RFID tag for wireless LAN position detection and management of people entering and leaving buildings, which also features an emergency message function.The combined features enable thorough and precise management of people entering a building and information about the position of individuals within. In emergencies, the emergency message function allows users to send a message to the control center, automatically informing disaster relief officials of their whereabouts”.
(via RFID in Japan)

Hitachi to Release WiFi Active RFID Tag