Perhaps you should try some spelling variations:
"modified parameter optimization algorithms" » "modified parameter optimisation algorithm", "modified parameter estimation algorithm", "modified parameter optimized algorithms", "modified parameters optimization algorithms"
"modified risk estimation algorithms" » "modified risk estimation algorithm", "modified risk optimisation algorithm", "modified risk approximation algorithms", "modified pose estimation algorithms", "modified bi1 estimation algorithms"

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: (("modified parameter optimization algorithms") OR ("modified risk estimation algorithms"))~.
• Removing quotes may allow a broader search: (( modified parameter optimization algorithms ) or ( modified risk estimation algorithms ))~.
• Adding a wildcard symbol may retrieve word variants: (("modified parameter optimization algorithms") or ("modified risk estimation algorithms"))*.