Perhaps you should try some spelling variations:
"modified rough approximation algorithm" » "modified rough approximation algorithms", "modified rough approximations algorithm", "modified one approximation algorithm"
"modified parameters optimization algorithm" » "modified parameter optimization algorithm", "modified parameter estimation algorithm", "modified parameters optimization algorithms", "modified parameters optimisation algorithm", "modified parameters estimation algorithm"

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• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"modified rough approximation algorithm\") OR (\"modified parameters optimization algorithm\"))~".
• Removing quotes may allow a broader search: (( modified rough approximation algorithm ) OR ( modified parameters optimization algorithm ))~.
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