I. Introduction
Neural networks (NNs), as an important class of machine learning algorithms, have been widely researched on its applications [1]-[4]. It has been proved that single hidden layer feedforward neural networks (SLFNs) have universal approximation capability [5]. Moreover, theories of ELM [6] further show that SLFNs with randomly generated input weights and hidden biases can also approximate any complex functions. Due to such an useful property, classifiers trained with ELM have been developed for pattern classification in recent years [6], [23].