| 摘要 |
A system involving a centralised server and a number of portable devices. When one of the devices is activated using a button B it transmits its current location and a unique ID which identifies the specific device to a central server. The ID is a short unique code, for example, 256 bits wide rather than any personal information about the current owner. The location is determined using the Global Positioning System (GPS) and the information is transmitted via SMS. The information is not continuously transmitted, but is sent a single time when activated by the owner of the device. When the server receives the signal from the device, it displays the location on a map and the identity of the device owner. The device may be easily activated without looking at it and has security measures to avoid accidental activation. |
