The Korean electronics giant's smartphones, which feature Google's (GOOG) Android software, are riding "an explosive wave of momentum" in N. America, eroding Apple's (AAPL) dominance, according to a new market survey by ChangeWave. The survey found that 50% of consumers who planned to buy a smartphone in the next 90 days expected to get an Apple iPhone. That's down from 71% in Sept., when the iPhone 5 launched. About 1 in 5 smartphone buyers surveyed planned to get a Samsung handset, up from 13% in Sept. and 19% in June when Samsung's Galaxy S3 debuted. Google edged up 0.2% to 724.93.