Perhaps you should try some spelling variations:
optimisation algorithm » optimization algorithms, estimation algorithm, estimation algorithms
time approximation » _ approximation
one approximation » _ approximation, rough approximations
qoe optimisation » qoe optimization, _ optimisation, game optimization

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: (( qoe optimisation algorithm ) OR ( ((one approximation) OR (time approximation)) algorithm ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( qoe optimisation algorithm ) or ( ((one approximation) OR (time approximation)) algorithm ))~".
• Adding a wildcard symbol may retrieve word variants: (( qoe optimisation algorithm ) or ( ((one approximation) OR (time approximation)) algorithm ))*.