Perhaps you should try some spelling variations:
optimization algorithms » optimisation algorithm, estimation algorithms, estimation algorithm
df optimization » _ optimization, qoe optimization, _ optimisation
force algorithm » source algorithm, search algorithm
using force » using morse, cutting force
modified df » modified _, modified adam, modified bi1

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (( (code OR core) using force algorithm ) OR ( modified df optimization algorithms ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( (code OR core) using force algorithm ) or ( modified df optimization algorithms ))~".
• Adding a wildcard symbol may retrieve word variants: (( (code OR core) using force algorithm ) or ( modified df optimization algorithms ))*.