Perhaps you should try some spelling variations:
optimization algorithms » optimisation algorithm, estimation algorithm, optimized algorithms
estimation algorithms » estimation algorithm, optimisation algorithm, approximation algorithms
invasive estimation » invasive ventilation
modified invasive » modified passive
df optimization » _ optimization, qoe optimization, _ optimisation
modified df » modified _, modified adam, modified bi1

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (( modified df optimization algorithms ) OR ( modified invasive estimation algorithms ))~.
• Adding a wildcard symbol may retrieve word variants: (( modified df optimization algorithms ) or ( modified invasive estimation algorithms ))*.