Because of a software glitch, the first high-tech "virtual fence" on the nation's borders remains inoperable, three months after its scheduled debut. "The integration of all the systems into a common operating picture continues to be the challenge," said Homeland Security spokesman Russ Knocke. Boeing has put new people on the project who are working to resolve the problems, he said. The individual components worked well, but the system integration did not, [Homeland Security Secretary Michael Chertoff] said. Boeing has "retooled their team on the ground and replaced some of the managers. ... They are now working through the problems of system integration as we speak," Chertoff said. "I think they put their A-team in place to do it."As reported previously in this blog, the problem seems to be integration complexity. The current virtual fence project consists of nine 98-foot towers, spaced a few miles apart, containing sensors, radar and specialized cameras. The integration of these components is an essential element in allowing the project to function as designed. Successfully integrating complex components is a substantial risk in any project containing multiple, complicated subsystems. Integration risks become especially pronounced in situations where integration essentially defines the project, such as this case. The risk increases further when the subsystems themselves consist of new, or unproven, technology. As an aside, it is interesting to note that the DHS is also evaluating construction of a physical border fence.