Perhaps you should try some spelling variations:
spatial optimization » spatial organization (Expand Search), path optimization (Expand Search), swarm optimization (Expand Search)
based optimization » whale optimization (Expand Search)
risk spatial » high spatial (Expand Search), fine spatial (Expand Search), via spatial (Expand Search)
binary risk » primary risk (Expand Search), dietary risk (Expand Search)
linac base » linac based (Expand Search)
base based » case based (Expand Search), blame based (Expand Search), made based (Expand Search)

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

• Removing quotes may allow a broader search: (( linac base based optimization algorithm ) OR ( binary risk spatial optimization algorithm )).