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

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

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