In Software Effort Estimation:

Since we know that they are three categories for software effort estimation i.e:

1) Algorithmic 2) Expert Estimation and 3) Machine Learning

Question 1 : Multi-objective Optimization is a new approach to predict effort estimation, is it a separate category? or it comes under the umbrella of Machine Learning.

If it is a separate category then we have four categories right?

1) Algorithmic 2) Expert Estimation and 3) Machine Learning 4) Multi-objective Optimization.

Question 2 : And Does PSO, Differential Evolution DE, Artificial BEE Colony and Ant Colony come under Multi-objective Optimization ???