since density is considered as one of the most important numerical indices to explain quantitative values of a plant community by affecting on many aspects and activity of ecosystem, on the other hand, awareness about plants distribution pattern in environment is an essential preparation for measurement and study of vegetative cover, therefore, in this research determination of density and dist...

Noncentral chi-square distributions play an important role in statistics. They occur for instance as exact or limiting distributions of test statistics under alternatives. To examine the power functions of such tests we come across the problem of comparing distribution functions of noncentral chi-square variables. In this section inequalities are presented, which make such a comparison possible...

With the rapid development of e-business, personalized recommendation has become core competence for enterprises to gain profits and improve customer satisfaction. Although collaborative filtering is the most successful approach for building a recommender system, it suffers from "shilling" attacks. In recent years, the research on shilling attacks has been greatly improved. However, the approac...