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

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( post optimization algorithms ) or ( ((one approximation) OR (time approximation)) algorithm ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( post optimization algorithms ) OR ( ((one approximation) OR (time approximation)) algorithm )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( post optimization algorithms ) or ( ((one approximation) OR (time approximation)) algorithm ))".
• Adding a wildcard symbol may retrieve word variants: (( post optimization algorithms ) or ( ((one approximation) OR (time approximation)) algorithm ))*.