Algorithm 1 BlueDetect IO detection and localization algorithm (outdoors ⇌ semi-outdoors).

input: B - Bluetooth signal (iBeacon), G - GPS signal, ${\sigma }_s$ - switching threshold, ${\sigma }_t$ - duration threshold output: Location of the mobile device case Outdoor ⇒ Semi-outdoor     if $G_{current}<{\sigma }_s*G_{previous}$ for ${\sigma }_t$ then         Turn on Bluetooth;         if No less than 2 beacons’ $B>B_{min}$ then            Turn off GPS;            Utilize B for localization;            Environment Type ← Semi-outdoor         else            Turn off Bluetooth;            Utilize G for localization;            Environment Type ← Outdoor         end if     end if case Semi-outdoor ⇒ Outdoor     if $B\in {\mathbf{B}}_{boundary}$ then         Turn off Bluetooth, Turn on GPS;         Utilize G for localization;         Environment Type ← Outdoor     else         Utilize B for localization;         Environment Type ← Semi-outdoor     end if