This year's themes are:

The Rise of Intelligent Software Systems and Machines
Nano/Bio Interface
Engineering Personal Mobility for the 21st Century
Supply Chain Management

So what is this symposium?

U.S. Frontiers of Engineering is an annual three-day meeting that brings together 100 of the nation's outstanding young engineers (ages 30-45) from industry, academia, and government to discuss pioneering technical and leading-edge research in various engineering fields and industry sectors. Participation is by invitation following a competitive nomination and selection process.

The program provides an opportunity for top-notch engineers, early in their careers, to learn about cutting-edge developments in fields other than their own, thereby facilitating collaborative work and the transfer of new approaches and techniques across fields. Through both formal sessions and informal discussions, the meetings have proven an effective mechanism for the establishment of cross-disciplinary and cross-sector contacts among this country's future engineering leaders.

The slides (and more) from last year's symposium are available, when the themes were:

ID and Verification Technologies
Engineering for Developing Communities
Engineering Complex Systems
Energy Resources for the Future

Some readers may be interested in Alessandro Vespignani's Complex Networks: Ubiquity, importance, and implications.