Perhaps you should try some spelling variations:
"defined network approximation algorithm" » "defined network approximation algorithms", "designed network approximation algorithm"
"modified objective estimation algorithms" » "modified objective estimation algorithm", "modified objective optimization algorithms", "modified objective optimisation algorithm", "modified objective allocation algorithms"

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• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"defined network approximation algorithm\") OR (\"modified objective estimation algorithms\"))~".
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