Perhaps you should try some spelling variations:
"modified df approximation algorithms" » "modified _ approximation algorithms", "modified one approximation algorithms", "modified time approximation algorithms", "modified adam approximation algorithms", "modified bi1 approximation algorithms"
"modified dfdamdamdaptive estimation algorithm" » "modified _damdamdaptive estimation algorithm", "modified adamdamdamdaptive estimation algorithm", "modified bi1damdamdaptive estimation algorithm"

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