Perhaps you should try some spelling variations:
optimisation algorithms » optimisation algorithm, optimization algorithms, estimation algorithms
policy optimization » topology optimization
policy estimation » pose estimation, motion estimation, policy simulation
risk optimisation » _ optimisation, risk estimation

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( ((policy estimation) OR (policy optimization)) algorithm ) or ( risk optimisation algorithms ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( ((policy estimation) OR (policy optimization)) algorithm ) OR ( risk optimisation algorithms )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( ((policy estimation) OR (policy optimization)) algorithm ) or ( risk optimisation algorithms ))".
• Adding a wildcard symbol may retrieve word variants: (( ((policy estimation) OR (policy optimization)) algorithm ) or ( risk optimisation algorithms ))*.