Algorithm 1 Server device

Input:$R_{msg}$ (Request message containing node ID, message ID, and GPS coordinates) Output:$Ac{k}_{msg}$ (Acknowledgment message)     $Alar{m}_{msg}$ (Alarm message generated)

1:procedure 2: Step 1: defining and initializing variables 3: Step 2: detecting events 4: while 1 do 5:  if $R_{msg}=true$ then 6:    Generate $Alar{m}_{msg}$ 7:    send $Ac{k}_{msg}$ back 8:    Print request message on screen. 9:  end if 10: end while 11:end procedure