Information Technology Reference
In-Depth Information
Ta b l e 2 .
Types of erroneous utterances
id
example utterance
problem
E1
“fetch”
object missing
E2
“go somewhere”
unspecific object
E3
“go the kitchen”
missing preposition
E4
“collect the bath room”
nonsense
E5
“smurf”
unknown word
E6 “the cup i need” or “the cup”
ill-formed syntax
can be nonsense when the objects do not match the attributes required for a parame-
ter as specified in our ontology. In cases such as the one in E4 the system rejects the
utterance since “the bath room” is not a “portable object” as required for the “collect”
skill. This is then also mentioned in an explanation given to the user. Words that do not
occur in our lexicon can not be processed. Hence, the system will fail when confronted
with unknown words. When the system is confronted with ill-formed syntax, it fails at
the syntactical processing stage. This is because the grammar cannot handle utterances
with unknown constructions.
4.2
Responsiveness
To evaluate the performance of our system in terms of speed, we evaluated the system
using the following domain. The example agent has four different skills: getting lost
(no parameter), going somewhere (1 parameter), moving an object to some location
(2 parameters) and moving an object from some location to some location (3 parame-
ters). Additionally, our domain contains different entities with appropriate attributes: a
kitchen (location), a bath (location), a coffee cup (portable object) and a football trophy
(decoration). Some of the synonyms for skills and entities are ambiguous, namely (1)
“go” may refer to “get lost” as well as to “go somewhere”, (2) “move” may refer to
“get lost”, “go somewhere”, “move something somewhere” or “move something from
somewhere to somewhere”, and (3) “cup” may refer to the coffee cup as well as to the
football trophy.
We tested four different versions of the system with different requests involving var-
ious degrees of complexity using the following utterances:
(i) “scram”
(ii) “go to the kitchen”
(iii) “could you please move the cup to the kitchen”
(iv) “go to the kitchen and move the cup to the bath room”
(v) “i need you to move the cup from the bath room to the kitchen”
Utterance (i) is a very simple request. It addresses a skill with no parameters and the
used synonym “scram” is unambiguous. The skill addressed in utterance (ii) involves
one parameter and the used synonym “go” is ambiguous. Utterance (iii) involves a skill
with two parameters and the synonym “move” is also ambiguous. Utterance (iv) is the
combination of utterances (ii) and (iii) linked with an “and”. The skill requested in
utterance (v) has three parameters and the synonym “move” is again ambiguous.
The depth of the search tree spanned in the planning process depends on the num-
ber of objects. For example, the depth of the search tree for utterance (i) is exactly 1
