In managing an underground facility, considering the enormous number of documents, the number of people who are involved with the management of electric power, communication, gas, water, sewage or the like, and expended hours, enormous cost and time have been needed so far. A wireless chip is attached...http://www.google.com/patents/US7905397?utm_source=gb-gplus-sharePatent US7905397 - Data management method and data management system
