Perhaps you should try some spelling variations:
"modified multiobjective optimization algorithm" » "modified multiobjective optimization algorithms", "modified multiobjective optimisation algorithm", "modified multiobjective estimation algorithm"
"modified robust estimation algorithmss" » "modified robust estimation algorithms", "modified robust estimation algorithm", "modified robust optimization algorithms", "modified robust optimization algorithmss", "modified pose estimation algorithmss", "modified risk estimation algorithmss"

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