The problem is simply that the dog owner is giving incomplete information to his canine auditor. The person needs to remember the five cardinal rules of journalism: "Tell your audience What, Who, Why, Where, and When." When one yells, "Be quiet!", it is often only the What that is communicated: the dog merely understands that someone, somewhere should perhaps shut up sometime.

What's needed is to be specific, like a good reporter. Let me elaborate:

What is wanted?	Quiet, silence, peace, repose.
Who should be quiet?	You, the dog that is now barking.
Why should I do this?	Because I am your master and have the power to withhold food and shelter from you; besides, I am a human being and we have 5,000 years of civilization, the power of language, and the Bomb.
Where do you want this done?	Here, in this place.
When do you want me to do this?	Right away, without another instant of stalling about it.

Therefore, to communicate all five cardinal elements of the command, the owner should stand over his pet, fix a stern gaze at the animal, and say loudly:

"Be quiet, instantly!"

while pointing at the floor. In effect, these actions convey the full message:

"[You] be quiet [here] instantly [because I'm your boss]!"

A slight modification of this method is required for owners of cats. The problem lies in the "Who" element of the command. While dogs have but one self, cats have nine, and each of those nine selves must be addressed separately for a command to be effective. Thus in the message:

"[You] get down [from this dining table] instantly [because I'm your boss]!"

every one of the cat's nine "Yous" has to be instructed. The only way the owner can do this is to repeat the command on nine different occasions. On each occasion, a feline ego-- such as #2, "I, the black panther who stalks by night," or #5, "I, the individual who just happened to be crossing this table on her way to the garden," or #6, "I, the cute kitten who can do no wrong," or #8, "I, the true owner of this house"-- will get the message. If even one of a cat's personalities is left uninstructed, she will assume that that one is still allowed to jump up on the table even though the other eight (hmmph, too bad for them!) have been forbidden to do so. Only when nine repetitions have covered all nine selves will the undesired behavior finally cease.