  We present our work on the multimodal coreference resolution task of the
Situated and Interactive Multimodal Conversation 2.0 (SIMMC 2.0) dataset as a
part of the tenth Dialog System Technology Challenge (DSTC10). We propose a
UNITER-based model utilizing rich multimodal context such as textual dialog
history, object knowledge base and visual dialog scenes to determine whether
each object in the current scene is mentioned in the current dialog turn.
Results show that the proposed approach outperforms the official DSTC10
baseline substantially, with the object F1 score boosted from 36.6% to 77.3% on
the development set, demonstrating the effectiveness of the proposed object
representations from rich multimodal input. Our model ranks second in the
official evaluation on the object coreference resolution task with an F1 score
of 73.3% after model ensembling.
