Perhaps you should try some spelling variations:
optimization algorithm » optimization algorithms, optimisation algorithm, estimation algorithm
df optimization » _ optimization, qoe optimization, _ optimisation
machine making » machine learning
making methods » learning methods, graining methods
modified df » modified _, modified adam, modified bi1

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( machine making methods algorithm ) or ( modified df optimization algorithm ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( machine making methods algorithm ) OR ( modified df optimization algorithm )).
• Adding a wildcard symbol may retrieve word variants: (( machine making methods algorithm ) or ( modified df optimization algorithm ))*.