Perhaps you should try some spelling variations:
optimisation algorithm » optimization algorithms, estimation algorithm, estimation algorithms
robust optimisation » robust optimization
risk optimization » robust optimization, _ optimization, game optimization
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: (( robust optimisation algorithm ) or ( ((risk optimization) or (qoe optimization)) algorithms ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( robust optimisation algorithm ) OR ( ((risk optimization) OR (qoe optimization)) algorithms )).
• Adding a wildcard symbol may retrieve word variants: (( robust optimisation algorithm ) or ( ((risk optimization) or (qoe optimization)) algorithms ))*.