Since the very early days of human/bear conflict in America (circa 14,000 B.C., when Giant Short Faced Cave Bears ate our ancestors pretty regularly, probably for making fun of the length of their faces), we've come up with some ingenious ways to defuse or avoid such conflict.
"Start a big fire to frighten them and sacrifice someone you don't like if that doesn't work " was popular for a while, but only with the survivors.
The "kill everything with claws and teeth until they stop eating us and go away" is the most time-tested method. More elegant methods have emerged in recent epochs, however, including "don't feed the bear your sandwich through the car window," "don't tease the bear by looking like a giant burrito wrapped in your sleeping bag smelling like food" and "don't leave your car and a sandwich unguarded in a bear neighborhood because they'll jack that sucker."
There are more direct methods to repel attack. Hikers carry giant cans of Mace or pepper spray filled with capsaicin (the oil in really hot peppers that makes them really hot) so they can spray bears the way they would a mugger, probably with the same results.
(Most frequent joke told to hikers heading into bear country: To be safe, wear bells to warn off the black bears, carry pepper spray to chase them off if you surprise them, and watch out for signs of grizzly bears: piles of bear scat containing little bells and smelling like pepper.)
Anti-bear technology has gotten more advanced with the release of a giant Taser designed to stun bears in the same way they stun muggers or completely innocent dudes just minding his own business and not bothering anyone and getting harassed by some power-mad cop ("Don't tase me, Mr. Ranger, sir.").
(In level of brutality it falls somewhere between these fashion-forward Tasers with designer colors and integrated MP3 players and this riot-control thing that looks like a Taser version of a Claymore mine, but not every personal protection system can be quite that horrifying.)
It can fire up to three pairs of micro-harpoons into three different targets (or one that you really don't like), each of which gets a similar charge simultaneously through wires that remain attached to the Taser.
It also fires the little spikes from as far away as 35 feet, rather than 15, has an aiming laser calibrated for that distance so you don't even have to aim, a charge-monitoring feature to make sure the bear gets maximum zap and a log feature so you can upload data and see how effectively the charge was delivered and decide whether or not the bear was able to eat you.
For a suggested retail price of $2,000, of course, it should carry itself into the back country and shoot a picture of you with the bear it incapacitates, but security always has an iffy ROI.
If you decide not to buy one and never get eaten by a bear, you didn't need to spend the money. If you do, you did.