customizable by the app developer but in the case of advertising the event might be a push notification with an ad. However, with a UID based system the users device must connect to an online server which is capable of understanding the beacons UUID. Once the UUID is sent to the server the appropriate message action is sent to a users device. Other methods of advertising are also possible with beacons, URIBeacon and Google's Eddystone allow for a URI transmission mode that unlike iBeacons UID doesn't require an outside server for recognition. The URI beacons transmit a URI which could be a link to a webpage and the user will see that URI directly on their phone. Notification and interaction Beacons can be associated with the artpieces in a museum to encourage further interaction. For example, a notification can be sent to user's mobile device when user is in the proximity to a particular artpiece. By sending user the notification, user is alerted with the artpiece in his proximity, and if user indicates their further interest, a specific app can be installed to interact with the encountered artpiece. In general, a native app is needed for a mobile device to interact with the beacon if the beacon uses iBeacon protocol; whereas if Eddystone is employed, user can interact with the artpiece through a physical web URL broadcast by the Eddystone. Indoor navigation Indoor positioning with beacons falls into three categories. Implementations with many beacons per room, implementations with one beacon per room, and implementations with a few beacons per building. Indoor navigation with Bluetooth is still in its infancy but attempts have been made to find a working solution. Many beacons per room With multiple beacons per room trilateration can be used to estimate a users' position to within about 2 meters. Bluetooth beacons are capable of transmitting their Received Signal Strength Indicator (RSSI) value in addition to other data. This RSSI value is calibrated by the manufacturer of the beacon to be the signal strength of the beacon at a known distance, typically one meter. Using the known output signal strength of the beacon and the signal strength observed by the receiving device an approximation can be made about the distance between the beacon and the device. However this approximation is not very reliable, so for more accurate position tracking other methods are preferred. Since its release in 2010