Proceedings - Österreichische Gesellschaft für Artificial Intelligence

Our ultimate goal is to develop computational
methods that can automatically retrieve omitted
locations. The present paper takes the first step
by defining the task, performing a focused data
analysis, and evaluating the ability of the two most
widely used resources in computational linguistics,
WordNet and FrameNet, for the purpose of identifying
motion verbs, for which locational inference
is particularly relevant.
Plan of the paper. Section 2 defines the task of
locational inference and discusses its challenges.
Section 3 presents a corpus annotation study which
provides ground truth of motion verbs and location
roles as well as an analysis. Section 4 evaluates
how well WordNet and FrameNet can be used to
tackle the identification of motion verbs.
2 Locational Inference and Motion
Verbs
2.1 Locational Inference
Locational inference is the special case of the recovery
of unrealized arguments or null instantiations
for semantic roles that denote places and
directions. Figure 1 shows our concept of a processing
pipeline for location inference. The task
consists of several subtasks. The first subtask (I.)
is the recognition of verbs that actually require
locational inference. This subtasks again decomposes
into two parts: first we verify that the verb
in question requires a location (1), and then we
check that the current instance of the lemma leaves
at least one location unrealized so that it must be
inferred (2). The second subtask, recovery (II.),
then attempts to identify the missing location from
the available locations in context (3., 4.). The
modeling part of this paper focuses on the first
recognition step, that is, the decision of whether
an event requires a location (Step 1).
2.2 Related Work
This task shows similarities to some existing NLP
processing paradigms. The most notable is semantic
role labeling or SRL (Gildea and Jurafsky,
2002), in the sense that locations can be seen
as specific semantic roles. Semantic roles have
also been employed as a basis for deciding entailment
(Burchardt et al., 2009). The division of
locational inference into recognition and recov-
event in text
1. does event require
a location?
2. does event leave a
location unrealized?
I. recognition
3. which locations
are available in the
context?
4. which location is
the missing one
(if any)?
II. recovery
Figure 1: Processing pipeline for locational inference
ery is also reminiscent of the frequent decomposition
of SRL into recognition and classification
steps. Traditionally, SRL concentrates on locally
realized arguments, but awareness is growing that
SRL needs to include non-local arguments. Gerber
and Chai (2010) found many implicit arguments
of nouns to be recoverable from prior context, and
a recent SemEval task (Ruppenhofer et al., 2010)
explicitly included unrealized arguments.
A second related task is coreference resolution
(Soon et al., 2001). The analogy applies in particular
to the second part of locational inference
(recovery). Similar to coreference resolution, we
have to construct a set of contextually available
"antecedents" for missing locations and pick the
correct one. However, here face "zero anaphora"
(Fillmore, 1986), which again makes it difficult
to identify features. Silberer and Frank (2012),
address the general problem but find it to be very
difficult. By focusing on location roles, we hope to
simplify the problem through limiting the semantic
types of possible antecedents.
2.3 Locational Inference and Motion Verbs
A fundamental question about locational inference
is what verbs it applies to. While it can be argued
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Proceedings of KONVENS 2012 (Main track: oral presentations), Vienna, September 19, 2012