Spoken Interactive Open-domain QA system
Dr Chiori Hori
ISL, Language Technology Institute

Human and machine dialog systems using a speech interface have been
intensively researched in the field of spoken language processing
(SLP). Such conversational dialogs to exchange information through
question answering (QA) are a natural communication modality. However,
state-of-the-art dialog systems only operate for specific-domain
question answering (SDQA) dialogs. To achieve more natural
communication between human beings and machines, spoken dialog systems
for open domains are necessary.  Specifically open-domain question
answering (ODQA) is an important function in natural
communication. Our goal is to construct a spoken interactive ODQA
system, which includes an ASR system and an ODQA system.

Two main issues that need to be addressed to construct spoken
interactive ODQA systems are:

1. The spoken QA problems:
   Recognition errors due to out-of-vocabulary degrade the performance of
   QA systems.  Some indispensable information to extract answers is
   deleted or substituted by other words.  To cope with this problem, 1.8
   million words recognition on real time using a weighted finite state
   transducer (WFST) is constructed. Approximation in on-the-fly
   composition is applied to decoding.

2. The interactive ODQA problems:

   Since user's questions are not restricted, system queries for
   additional information to extract answers and effective interaction
   strategies using such queries cannot be prepared before the user
   inputs the question. To require additional information based on user's
   question and retrieved corpus, systems obtain additional information
   from users by using disambiguating queries generated by combining
   interrogatives and phrases in users' questions to query modifiers.