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

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• Performing a fuzzy search may retrieve terms with similar spellings: (( qoe optimisation algorithm ) or ( ((one approximation) OR (time approximation)) algorithms ))~.
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