Time Scale for Redefinitions

The SI can be improved by modernizing the way units are defined. In particular, the definitions of the kilogram, ampere, kelvin and mole are based on 19th century science and technology and can be replaced by ones that take into account subsequent progress in physics. 

If an update of the SI were done by specifying values of fundamental constants, the concepts of base units and derived units would not be necessary. 

If there are no persistent problems with experiments, the changes could be made in 2011. 

---