This article briefly discusses recurrent neural networks and bidirectional recurrent neural networks. A conditional random field is also described. In particular, we consider the vector representation in the form of the ELMo model, the bidirectional language model and its fine-tuning. A diagram of the architecture of a bidirectional recurrent neural network with CRF is also given.

Keywords: named entity recognition, neural network, word vector representation, language model, conditional random field, neural network architecture, recurrent neural network, natural language processing, bidirectional recurrent neural network