目前,举世瞩目的北京奥运会已经迎来100天倒计时,几乎所有准备工作都到了最后的冲刺阶段。与此同时,上海世博会也进入了最为关键的筹办时期,奥运之后将启动600天行动计划。北京奥运会、上海世博会,均为人群高度聚集的活动,在恐怖活动日益猖獗的今天,其安全问题愈来愈受到全世界的高度关注。2005年日本爱知世博会创下了 At present, the world-renowned Beijing Olympic Games has ushered in 100 days countdown, almost all preparatory work has reached the final sprint stage. At the same time, the Shanghai World Expo has also entered the most crucial preparatory period, after the Olympic Games will start a 600-day plan of action. The Beijing Olympic Games and the Shanghai World Expo are all highly-crowded activities of the population. As the terrorist activities are increasingly rampant, the security of the Beijing Olympic Games and the Shanghai World Expo has drawn increasing attention from all over the world. 2005 Aichi Expo in Japan hit a record