Hisashi Kawai

Also published as: Kawai Hisashi


2022

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Can We Train a Language Model Inside an End-to-End ASR Model? - Investigating Effective Implicit Language Modeling
Zhuo Gong | Daisuke Saito | Sheng Li | Hisashi Kawai | Nobuaki Minematsu
Proceedings of the Second Workshop on When Creative AI Meets Conversational AI

Language models (LM) have played crucial roles in automatic speech recognition (ASR) to enhance end-to-end (E2E) ASR systems’ performance. There are two categories of approaches: finding better ways to integrate LMs into ASR systems and adapting on LMs to the task domain. This article will start with a reflection of interpolation-based integration methods of E2E ASR’s scores and LM’s scores. Then we will focus on LM augmentation approaches based on the noisy channel model, which is intrigued by insights obtained from the above reflection. The experiments show that we can enhance an ASR E2E model based on encoder-decoder architecture by pre-training the decoder with text data. This implies the decoder of an E2E model can be treated as an LM and reveals the possibility of enhancing the E2E model without an external LM. Based on those ideas, we proposed the implicit language model canceling method and then did more discussion about the decoder part of an E2E ASR model. The experimental results on the TED-LIUM2 dataset show that our approach achieves a 3.4% relative WER reduction compared with the baseline system, and more analytic experiments provide concrete experimental supports for our assumption.

2011

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Toward Construction of Spoken Dialogue System that Evokes Users’ Spontaneous Backchannels
Teruhisa Misu | Etsuo Mizukami | Yoshinori Shiga | Shinichi Kawamoto | Hisashi Kawai | Satoshi Nakamura
Proceedings of the SIGDIAL 2011 Conference

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Improving Related Entity Finding via Incorporating Homepages and Recognizing Fine-grained Entities
Youzheng Wu | Chiori Hori | Hisashi Kawai | Hideki Kashioka
Proceedings of 5th International Joint Conference on Natural Language Processing

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Answering Complex Questions via Exploiting Social Q&A Collection
Youzheng Wu | Chiori Hori | Hisashi Kawai | Hideki Kashioka
Proceedings of 5th International Joint Conference on Natural Language Processing

2010

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Exploiting Social Q&A Collection in Answering Complex Questions
Youzheng Wu | Kawai Hisashi
CIPS-SIGHAN Joint Conference on Chinese Language Processing

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Modeling Spoken Decision Making Dialogue and Optimization of its Dialogue Strategy
Teruhisa Misu | Komei Sugiura | Kiyonori Ohtake | Chiori Hori | Hideki Kashioka | Hisashi Kawai | Satoshi Nakamura
Proceedings of the SIGDIAL 2010 Conference