1 ARCHITECTURE OF A QUESTION ANSWERINGTHESE THREE TYPES OF QUESTION HAVE IN COMMONSYSTEM APPLIED TO TEMPORALITYTHE NECESSITY OF AN ADDITIONAL PROCESSING IN ORDERTO BE SOLVED
3.1 Architecture of a Question Answering
These three types of question have in common
System applied to Temporality
the necessity of an additional processing in order
to be solved. Our proposal to deal with them is
The main components of the Temporal Question
to superpose an additional processing layer, one by
Answering System are (c.f. figure 2) top-down:
each type, to a current General Purpose Question
Question Decomposition Unit, General purpose
Answering system, as it is shown in Figure 1. This
Q.A. system and Answer, Recomposition Unit.
layer will perform the following steps:
Decomposition of the question into simple
events to generate simple questions (sub-
questions) and the ordering of the sub-
questions.
Sending simple questions to a current General
Purpose Question Answering system.
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Receiving the answers to the simple questions
from the current General Purpose Question
Answering system.
Filtering and comparison between sub-answers
to build the final complex answer.
Figure 2: Temporal Question Answering System
These components work all together for the ob-
tainment of a final answer. The Question Decom-
position Unit and the Answer Recomposition Unit
Figure 1: Multi-layered Architecture of a Q.A.
are the units that conform the Temporal Q.A. layer
which process the temporal questions, before and
have proposed a specific layer oriented to pro-
after using a General Purpose Q.A. system.
cess each type of temporal questions.
The final goal of this paper is to introduce and
The Question Decomposition Unit is a prepro-
evaluate the first part of the temporal question
cessing unit which performs three main tasks.
processing layer: the Question Decomposition
First of all, the recognition and resolution of
Unit.
temporal expressions in the question. Sec-
ondly, there are different types of questions,
Next section shows the different parts of the unit
according to the taxonomy shown in section 2.
together with some examples of their behavior.
Each type of them needs to be treated in a dif-
4 Question Decomposition Unit
ferent manner. For this reason, type identifica-
tion must be done. After that, complex ques-
The main task of this unit is the decomposition of
tions of types 3 and 4 only, are split into sim-
the question, which is divided in three main tasks or
ple ones, which are used as the input of a Gen-
modules:
eral Purpose Question-Answering system. For
example, the question “Where did Bill Clinton
Type Identification (according to the taxonomy
proposed in section 2)
study before going to Oxford University?”, is
divided into two sub-questions related through
Temporal Expression Recognition and Resolu-
the temporal signal before:
tion
– Q1: Where did Bill Clinton study?
Question Splitter
– Q2: When did Bill Clinton go to Oxford
These modules are fully explained below. Once
University?
the decomposition of the question has been made,
the output of this unit is: