Perhaps you should try some spelling variations:
"modified allocation optimization algorithm" » "modified allocation optimization algorithms", "modified allocation optimisation algorithm", "modified allocation estimation algorithm", "modified location optimization algorithm"
"modified invasive approximation algorithms" » "modified passive approximation algorithms"

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• Performing a fuzzy search may retrieve terms with similar spellings: (("modified invasive approximation algorithms") or ("modified allocation optimization algorithm"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("modified invasive approximation algorithms") OR ("modified allocation optimization algorithm"))*.
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