When an entity contains one or more entities, these particular entities are referred to as nested entities. The Layered BiLSTM-CRF model can use multiple BiLSTM layers to identify nested entities. However, as the number of layers increases, the number of labels that the model can learn decreases, and it may not even predict any entities, thereby causing the model to stop stacking. Furthermore, the model will be constrained by the one-way propagation of information from the lower layer to the higher layer. The incorrect entities extracted by the outer layer will affect the performance of the inner layer. We propose a novel neural network for nested named entity recognition (NER) that dynamically stacks flat NER layers to address these issues. Each flat NER layer captures contextual information based on a pretrained model with more robust feature extraction capabilities. The model parameters of a flat NER layer and its input are entirely independent. The input of each layer is all of the word representations generated by the input sequence through the embedding layer. The independent input ensures that different flat NER layers will not be interfered with by other flat NER layers during model training and testing to reduce error propagation. Experiments show that our model obtains F1 scores of 76.9%, 78.1%, and 78.0% on the ACE2004, ACE2005, and GENIA datasets, respectively.

In recent years, many scholars have chosen to use word lexicons to incorporate word information into a model based on character input to improve the performance of Chinese relation extraction (RE). For example, Li et al. proposed the MG-Lattice model in 2019 and achieved state-of-the-art (SOTA) results. However, MG-Lattice still has the problem of information loss due to its model structure, which affects the performance of Chinese RE. This paper proposes an adaptive method to include word information at the embedding layer using a word lexicon to merge all words that match each character into a character input-based model to solve the information loss problem of MG-Lattice. The method can be combined with other general neural system networks and has transferability. Experimental studies on two benchmark Chinese RE datasets show that our method achieves an inference speed up to 12.9 times faster than the SOTA model, along with a better performance. The experimental results also show that this method combined with the BERT pretrained model can effectively supplement the information obtained from the pretrained model, further improving the performance of Chinese RE.

Hex is a board game with simple rules and complex strategy. In the recent years, hex is becoming more and more popular. (Hex is a game with simple rules and complex strategies which is becoming more and more popular recent years.) Although we have used Min-max tree search ^[1] and Alpha-Beta pruning ^[2] during game , the program still has a difficulty to dealing with some situations well . In this paper, we will instruct(describe) a condition which is difficult to deal with existed in hex. By analyzing this situation we found a special and important area called 'connected-region' and we will apply it to the evaluation function. Our experiment found that we will make program get win easier by using this strategy.