Context
Verbmobil
also provides us with the following two sentences:
a. Attach
the amplifier to the output terminal with the red wire.
b. Attach the amplifier to the output terminal with the red dot
(33).
These
sentences are very, very similar- in fact, they only differ by one
noun! However, in order to process them, a computer with NLP capabilities
would have to know that “with the red dot” is an adjectival
phrase, describing the terminal, and “with the red wire”
is an adverbial phrase that describes the method of attachment.
Let’s
take both of Verbmobil’s sentences and demonstrate how interpreting
them in the correct way requires two types of specialized knowledge.
We
can come to the first of these by attempting to interpret sentence
(b) in the same method as sentence (a). That is, we can rephrase
the sentence as “Use the red dot to attach the amplifier to
the output terminal.” This is clearly incorrect, and a computer
could determine this from the definition of dot: [example]. A dot
is not an object in three-dimensional space and thus cannot connect
two objects in three-dimensional space, albeit not being long enough.
This is simple common sense. Thus, in order to have NLP capabilities,
a computer will have to have common-sense knowledge. It would begin
to acquire it simply by being able to access the definitions of
many words. Next, it would need to know the connections between
definitions. It would need to know, for example, that after one
goes through a doorway one is inside a room.
Now
let’s try to interpret sentence (a) like sentence (b). As
a refresher, sentence (a) is: “Attach the amplifier to the
output terminal with the red wire.” If we read “with
the red wire” as an adjectival phrase as it is in sentence
(b), the sentence will mean: “Attach the amplifier to the
output terminal that has a red wire on it.” At first, it seems
that this slight ambiguity does not make much of a difference. However,
assuming that the computer possesses some capacity to process language
in a systematic way, it will notice that the sentence contains no
specification regarding how the two should be attached—there
is no adverbial phrase featuring such an instruction. The computer,
then, may believe that an “amplifier” and an “output
terminal with a red wire” are two things that can be attached
to each other without the use of a wire—even though the wire
exists in the sentence! This is, at best, absurd. However, in order
to fix it, one would have to know something about the world that
is not easily categorized.
Such is the goal of the CYC knowledge base, which attempts to encode
a vast amount of information in order to represent all fundamental
human knowledge. CYC stores pieces of information bundled together
with assertions that connect them to one another. The database
is broken down into several categories that form a pyramid of associations.
These include: living things, organizational plans, politics and
warfare, and events and scripts. CYC uses a calculus-based representation
language called CycL in order to store the database.
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