  Multi-criteria Chinese word segmentation (MCCWS) aims to exploit the
relations among the multiple heterogeneous segmentation criteria and further
improve the performance of each single criterion. Previous work usually regards
MCCWS as different tasks, which are learned together under the multi-task
learning framework. In this paper, we propose a concise but effective unified
model for MCCWS, which is fully-shared for all the criteria. By leveraging the
powerful ability of the Transformer encoder, the proposed unified model can
segment Chinese text according to a unique criterion-token indicating the
output criterion. Besides, the proposed unified model can segment both
simplified and traditional Chinese and has an excellent transfer capability.
Experiments on eight datasets with different criteria show that our model
outperforms our single-criterion baseline model and other multi-criteria
models. Source codes of this paper are available on Github
https://github.com/acphile/MCCWS.
