Can you see the dog from a back (preferably upstairs) window? If so, just to develop the Pavlov theme (at least this is scientifically proven to be effective), you could try shooting it with airgun pellets when barking. Dogs are intelligent, it will soon make the connection...
peacefully checking out the local felines = no pain
barking at pedestrians = air gun pellet in the head
It's also proven that dogs
enjoy discipline... he'll love you for it in the end and you get to play out any Lee Harvey Oswald fantasies you may have in the meantime.
Hey, it was just an idea...
