Perhaps you should try some spelling variations:
"modified parameter optimisation algorithm" » "modified parameter optimization algorithms", "modified parameter estimation algorithm", "modified parameter optimization algorithm"
"modified passive estimation algorithms" » "modified passive estimation algorithm", "modified passive optimization algorithms", "modified passive approximation algorithms", "modified pose estimation algorithms", "modified adaptive 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 passive estimation algorithms") OR ("modified parameter optimisation algorithm"))~.
• Removing quotes may allow a broader search: (( modified passive estimation algorithms ) or ( modified parameter optimisation algorithm ))~.
• Adding a wildcard symbol may retrieve word variants: (("modified passive estimation algorithms") or ("modified parameter optimisation algorithm"))*.