Perhaps you should try some spelling variations:
"modified lighting approximation algorithms" » "modified diophantine approximation algorithms", "modified caging approximation algorithms"
"modified parameter optimized algorithms" » "modified parameter optimized algorithm", "modified parameter optimizer algorithms", "modified parameter optimization algorithms"

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("modified lighting approximation algorithms") OR ("modified parameter optimized algorithms"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"modified lighting approximation algorithms\") OR (\"modified parameter optimized algorithms\"))".
• Removing quotes may allow a broader search: (( modified lighting approximation algorithms ) OR ( modified parameter optimized algorithms )).
• Adding a wildcard symbol may retrieve word variants: (("modified lighting approximation algorithms") OR ("modified parameter optimized algorithms"))*.