evaluating of different variables with ACO

hello

i have the main code 'aco.m' and related functions with an excel file. here we consider QOS for evaluation which can be for one or combination of other factors. 'hmm' is used to predict the values considered and then evaluating the population. every ant considered from population is a response or combination of factor. the evaluation is done by ants movement. the final response 'cost' vs 'iteration' should be in step-by-step decreasing order but as seen in the attached files is fixed value of about '0.3'. is there any suggestion to fix the problem?

thanks in advance.