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

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "(( modified invasive estimation algorithms ) OR ( modified df optimisation algorithm ))~".
• Adding a wildcard symbol may retrieve word variants: (( modified invasive estimation algorithms ) OR ( modified df optimisation algorithm ))*.