Been A while since I've checked in here, but having an issue with Loki lately.  About 2 months ago he started to growl or try to nip at dogs that he did not know (randomly seemingly).  This was attributed to being attacked vigorously once by an off leash Russel and bit by a shih tzu, but the justification doesn't matter.

When loki will growl i move him aside and tell him to be quiet, or I did at first, I also tell him he is being bad.  This however only escalated over time and my next idea was to remove him from the scene altogether.  If he started to act out in an aggressive manner (which he would do if large dogs were across the street even) I would pick him up, turn him so he could not see and silence him sternly.    this however also has had no effect, he has now gone from only being unpleasant with dogs he doesn't know, to randomly with some dogs he knows and often played with (the vast majority of the time it is males, even the mastiff in the building..). 

I am not sure what is up here, if he is taking this whole turf thing to seriously, he has always been particularly dominant, fortunately so am I, but many other dogs are not, and I think he may be trying to bully them.  Any suggestions on what more I can do to correct this, showing him that he is in no power and absolutely no in charge has done little to rectify the situation. 

He is currently 13 mos , and this started in small bits at 10 mos.  I am unsure as to whether this is a dominance or a fear issue.