NEW YORK, Aug 28 - Stocks opened higher on Thursday after a report showed that the nation's economy expanded at a faster rate in the second quarter than previously thought. The blue-chip Dow Jones industrial average <.DJI> was up 15.01 points, or 0.16 percent, at 9,348.80. The broader Standard & Poor's 500 Index <.SPX> rose 1.75 points, or 0.18 percent, to 998.54. The technology-laced Nasdaq Composite Index <.IXIC> was up 5.91 points, or 0.33 percent, at 1,788.04.//