Tag-only aging-counter localization for the R-LIM2 system

With the large number of items stored in present-day libraries, locating the exact position of an item is time-consuming. This is true not only for poorly managed libraries, but also for well maintained libraries. In the former case, the problem is rather serious. Even though an item may be somewhere in the library, the fundamental role of the library may not be fulfilled, if a user cannot locate the item. In the latter case, a user still needs to perform a tedious shelf search to locate the item. In the first version of the RFID-based Library Management (R-LIM) system, we attached expensive RFID antennas to every shelf, to acquire localization information about the items. However, the solution was not cost-effective, due to the large number of RFID antennas needed. Therefore, in this study, we propose tag-only aging-counter localization for R-LIM, which does not require shelf antennas to determine book locations. In this more recent version, viz., the R-LIM2 system, we replace expensive antennas with inexpensive RFID tags, which enables us to build an affordable system. By associating RFID tags attached to books with those attached to shelves, via periodic tag scans, we determine the exact location of books. This paper describes the aging-counter localization algorithm developed for R-LIM2, and explains how it can be integrated with other parts of the system to locate a book in a search.