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