Nearly half of South Korean chief executive officers (CEOs) view a double-dip recession in the United States as the most worrisome risk facing the global economy in recent months, a poll showed Tuesday. According to Samsung Economic Research Institute\'s survey of 295 CEOs, 48 percent of the respondents said that their biggest global economic concern is the U.S. economy relapsing into a double-dip recession. The poll was conducted during the second week of September.