About the Authors

Frank Schweitzer

To whom correspondence should be addressed. E-mail: fschweitzer@ethz.ch

Affiliation Chair of Systems Design, ETH Zurich, Zurich, Switzerland

Robert Mach

Affiliation Chair of Systems Design, ETH Zurich, Zurich, Switzerland

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Analyzed the data: RM. Wrote the paper: FS.