SAN FRANCISCO • For years, science fiction moviemakers have been making us fear the bad things that artificially intelligent machines might do to their human creators. But for the next decade or two, our biggest concern is more likely to be that robots will take away our jobs or bump into us on the highway. Now, five of the world's largest tech companies are trying to create a standard of ethics around the creation of artificial intelligence (AI). While science fiction has focused on the existential threat of AI to humans, researchers at Google's parent company, Alphabet, and those from Amazon, Facebook, IBM and Microsoft have been meeting to discuss more tangible issues, such as the impact of AI on jobs, transportation and even warfare. Tech companies have long over-promised what artificially intelligent machines can do.