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<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Towards Modeling Conceptual Dependency Primitives with Image Schema Logic</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Jamie C. MACBETH</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Dagmar GROMANN</string-name>
          <email>dagmar.gromann@gmail.com</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Smith College</institution>
          ,
          <addr-line>Northampton, MA, 01063</addr-line>
          ,
          <country country="US">USA</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>University of Vienna</institution>
          ,
          <addr-line>Gymnasiumstraße 50, A-1190 Vienna</addr-line>
          ,
          <country country="AT">Austria</country>
        </aff>
      </contrib-group>
      <abstract>
        <p>Conceptual Dependency (CD) primitives and Image Schemas (IS) share a common goal of grounding symbols of natural language in a representation that allows for automated semantic interpretation. Both seek to establish a connection between high-level conceptualizations in natural language and abstract cognitive building blocks. Some previous approaches have established a CD-IS correspondence. In this paper, we build on this correspondence in order to apply a logic designed for image schemas to selected CD primitives with the goal of formally taking account of the CD inventory. The logic draws from Region Connection Calculus (RCC-8), Qualitative Trajectory Calculus (QTC), Cardinal Directions and Linear Temporal Logic (LTL). One of the primary premises of CD is a minimalist approach to its inventory of primitives, that is, it seeks to express natural language contents in an abstract manner with as few primitives as possible. In a formal analysis of physical primitives of CD we found a potential reduction since some primitives can be expressed as special cases of others.</p>
      </abstract>
      <kwd-group>
        <kwd />
        <kwd>Conceptual Dependency</kwd>
        <kwd>Formal Modeling</kwd>
        <kwd>Image Schemas</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>Natural language understanding remains to be one of the major challenges of modern
Artificial Intelligence (AI) and cognitive systems. One approach to tackling this challenge
is to map the potentially infinite compositional variety of natural language sequences
onto abstract, unambiguous base forms in a (semi-)formal representation. Conceptual
Dependency (CD) comprises one such framework that performs this function by
decomposing language into complex combinations of language-independent conceptual
primitives [14,15]. CD evolved to reduce the number of conceptual primitives in the system,
generalizing them, increasing levels of decomposition, and reducing chances of multiple
representations of the same concept.</p>
      <p>
        A second major such system is that of Lakoff [7] and Johnson [5] called image
schemas (IS), building on embodied cognition [16]. Sensori-motor experiences with the
external world form patterns that are believed to shape abstract conceptualizations, such
as reasoning and language, and they are generally described as spatio-temporal
relationships. A first important step towards image-schematic computational models is their
unambiguous, formal representation. A formalization approach to image schemas, the
socalled Image Schema Logic ISLM, builds on various calculi for modeling their spatial
and temporal dimension, but also movement and dynamic dimension. A correspondence
between CD and IS has been established before [
        <xref ref-type="bibr" rid="ref1">10</xref>
        ] and backed with empirical evidence
[2].
      </p>
      <p>
        Building on this previous correspondence, we evaluate the utilization of ISLM for
modeling CD primitives. Since CD representations lack a level of formality, utilizing a
well-defined logic towards this end can be highly beneficial to check on the CD inventory
for potential redundancies. As a very first experiment, this paper models a selection of
physical primitives that are mapped to a comparable set of image schemas, as established
in previous work [
        <xref ref-type="bibr" rid="ref1">10</xref>
        ], with a view to evaluating their correspondence in ISLM. We found
that certain primitives could be removed without loss of CD expressiveness.
      </p>
    </sec>
    <sec id="sec-2">
      <title>2. Conceptual Dependency</title>
      <p>This section first introduces Conceptual Dependency (CD) and a selected number of
primitives focusing on physical aspects. It then continues to elaborate on previously
established correspondences between CD and image schemas as a basis for our assumption
that ISLM can be applied to formalizing selected CD primitives.</p>
      <sec id="sec-2-1">
        <title>2.1. Conceptual Dependency Primitives</title>
        <p>As a theory of meaning representation, CD was developed as an alternative natural
language understanding system to formal, linguistic theories at that time [14,15,9]. It intends
to equip computational systems with human-like understanding of language that mirrors
human cognition. It decomposes meaning of natural language into language-agnostic
structures, called conceptual primitives.</p>
      </sec>
      <sec id="sec-2-2">
        <title>2.2. CD Constructs and Syntax</title>
        <p>The main well-formed expression in the Conceptual Dependency representation system
is the conceptualization. CD conceptualizations have basic elements that are described
and depicted in Table 1.</p>
        <p>
          CD has numerous primitives used to represent thought, perception, social
interaction, and communication (see [15]). However, in this paper, we narrow our focus to its
physical, spatial, and object-defining primitives, whose names and descriptions are given
in Table 2. Example sentences in Table 2 are taken from a previous study on
crowdsourcing the annotation of natural language sentences with CD primitives [
          <xref ref-type="bibr" rid="ref2">11</xref>
          ].
CONTAIN is utilized to specify physical objects in conceptualizations, which is why it is also
provided.
        </p>
        <p>Denominations of CD primitives resonate English words, however, the concepts they
identify differ from the lexical definitions of those words. For instance, “ingest” relates
to events of animate beings consuming food or drinks. The CD primitive INGEST is
broader in meaning as it relates to a variety of acts where a substance or object enters
[15]. Examples of full conceptualization diagrams are given in Table 4.</p>
        <p>CD Construct</p>
        <p>Description
PP ks +3 ACT
ACT o</p>
        <p>PP
PPs
ACTs
sk
sk</p>
        <p>TJ
o
o
o
3+
r
3+
ACT o</p>
        <p>D</p>
        <p>PP jt
PP jt
/ PP1</p>
        <p>PP2
4* PA
/ PA1</p>
        <p>PA2</p>
        <p>Picture producers (PPs) denote physical objects serving in various roles
in a conceptualization. In representing the sentence “Amy took a
breath,”, “Amy” and “breath” (or “air”) are PPs.</p>
        <p>ACTs are conceptual primitives representing things that can be done by
an actor to an object, or events that can happen to an object. PTRANS
and INGEST, described in Table 2, are examples of ACTs.</p>
        <p>One kind of CD conceptualization is an ACT performed by a PP as the
actor. For example, for “Amy took a breath,” could be (partially)
represented by Amy ks</p>
        <sec id="sec-2-2-1">
          <title>3+ INGEST. The double arrow represents the</title>
          <p>two-way dependency relationship between the actor and the ACT.</p>
          <p>A conceptualization can have a PP as an object. The arrow points from
the object PP to the primitive ACT having that PP as an object. For
example, the PP “air” could serve as the object of an INGEST for “Amy
took a breath.”
A conceptualization can have a direction case (also called the
DIRECTION primitive). Directions are specified as the locations of
PPs, with the two PPs indicating the “from” and “to” for primitive acts
involving movement. For example, for “Amy took a breath”, PP1, the
destination of the movement of air, would be Amy’s lungs.</p>
          <p>Picture producers can be described by picture aiders (PAs), “state”
predicates that take the form STATE(VALUE). CONTAIN() is an
example of such a state predicate.</p>
          <p>Picture producers can go through state changes described by a pair of
PAs. A state change of a PP is also a type of ACT.</p>
          <p>The result causation connective (indicated by the triple arrow labeled
“r”), which connects two conceptualizations, indicates that one event or
act resulted in another.
the body of an animate being, such as air, injections, transdermal absorption into the
skin or even single-cell organisms absorbing a molecule through its cell wall. Some
of the primitives have abbreviated names; for example PTRANS is short for “Physical</p>
        </sec>
        <sec id="sec-2-2-2">
          <title>TRANSfer”.</title>
        </sec>
      </sec>
      <sec id="sec-2-3">
        <title>2.3. Conceptual Dependency and Image Schemas</title>
        <p>Image schemas were introduced as abstract spatio-temporal relationships that aim to
bridge the gap between sensorimotor, embodied experiences and high-level
conceptualizations, such as natural language and reasoning. Image Schemas generalize
sensorimotor experiences, by which they abstract away from lexical manifestations of language,
similar to CD. For instance, repeated experiences of objects or people in concave objects,
such as water in a glass, a tissue in a box, a person in a room, reinforce our basic pattern
of the image schema CONTAINMENT, that is, something with an inside, an outside, a
boundary, and a container where becoming contained at some moment in time requires
motion.</p>
        <p>
          First correspondences between CD primitives and image schemas were established
on a theoretical basis with annotations of natural language examples by three experts
[
          <xref ref-type="bibr" rid="ref1">10</xref>
          ] and are depicted in Table 3. This mapping has been experimentally reinforced by
replicating a crowdsourcing-based annotation project of CD primitives [
          <xref ref-type="bibr" rid="ref2">11</xref>
          ] for image
schemas, uitilizing the same dataset of linguistic sequences for both experiments [2]. It
has to be noted that several distinct physical primitives can be expressed by identical
(combinations of) image schemas. This repetition in image-schematic mapping
motivated our assumption that more complex physical primitives, such as INGEST and
EXPEL that map to three image schemas, might be expressible as a combination of less
complex primitives, such as PTRANS and CONTAIN. It seemed only natural to utilize
an existing, closely related logic to formally analyze this assumption.
        </p>
        <p>A second major motivator for our choice of logic was the existing modeling of
dynamic aspects of CONTAINMENT [3], one of the central image schemas in our
mapping to CD primitives, which generally occurs in combination with movement along
a SOURCE PATH GOAL. As such it provides an excellent basis for formally analyzing
complex physical primitives and the feasibility of expressing more complex primitives
with simpler ones, thereby reducing the number of required primitives to model meaning
underlying natural language sequences.</p>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>3. Formalization Language</title>
      <p>We rely on a previously introduced formal language for image schema modeling called
ISLM [4] and refer the interested reader to this reference for a full account. In this paper,
we will limit our description to an overall summary of specific crucial elements of the
logic that draws from existing calculi, required to model the selected CD primitives. The
logic is a combined one of RCC-8, cardinal directions, QTC, and LTL with 3d Euclidean
space for the spatial domain briefly touched upon in this chapter.</p>
      <sec id="sec-3-1">
        <title>3.1. Spatial Dimension</title>
        <p>
          Building on previous work, such as [1], ISLM utilizes Region Connection Calculus
(RCC-8) [
          <xref ref-type="bibr" rid="ref3">12</xref>
          ] for basic topological relations, in which two objects can be disconnected
(DC) or partially overlapping (PO). Also, one object can be a proper part of another
object (PP), a tangential proper part of another object (TPP), or a non-tangential proper part
of another object (NTPP). Thereby, it is possible to denote the (lack of) contact between
two objects. To model directionality, Ligozat’s [8] cardinal directions are applied in the
mode of a fixed observer outside the model, which results in six binary predicates: Left,
        </p>
      </sec>
      <sec id="sec-3-2">
        <title>Right, FrontOf, Behind, Above, and Below.</title>
      </sec>
      <sec id="sec-3-3">
        <title>3.2. Movement Dimension</title>
        <p>To deal with the dynamic aspects of movement, the logic relies on Qualitative
Trajectory Calculus (QTC) [17] and selects three possible movements of objects in relation to
each other from its variant QTCB1D: object O1 moves towards O2 (O1 O2), object O1
moves away from O2 (O1 - O2), and object O1 is at rest with respect to O2’s position
(O1 j O2).</p>
      </sec>
      <sec id="sec-3-4">
        <title>3.3. Temporal Dimension</title>
        <p>
          To simplify the complexity of modeling time in cognitive theories, ISLM relies on a linear
temporal logic (LTL) over the reals [
          <xref ref-type="bibr" rid="ref4">6,13</xref>
          ]. The syntax is as follows:
        </p>
        <p>j ::= p j &gt; j :j j j ^ j j jU j
This allows us to express Fj (at some time in the future, j) defined as &gt;U j, and Gj
(at all times in the future, j) defined as :F:j.</p>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>4. A Comparison of Requirements</title>
      <p>One of the most crucial aspects of CD is that it requires a PP, a picture producer, to be
a physical object. Image schemas, in contrast, have no such requirement, even though it
might be counterintuitive to model image schemas without any relation to objects [3].
A dependency between a PP and some primitive ACT is established, which might be a
mental operation [15]. For instance, to “eat” means to take something inside, to INGEST
it. This ACT requires a clear direction to the inside of the object. CD originally was
highly diagrammatic as depicted with the visual representation of the DIRECTION case
in Table 1, which states that some object on the left hand side is moved from a previous
location on the lower right hand side of the diagram to a new location on the upper right
hand side of the diagram.</p>
      <p>Requirements specific to INGEST and EXPEL ACTs are the movement of a PP in
a specific DIRECTION with the entailed change of location. In contrast to other types
of movement, this CD primitive involves a relation to CONTAIN, either as leaving or
entering a container. However, this relation is not explicitly established in CD. In the
example diagrams in Table 2, the PP “frog” becomes CONTAINed in a PP “box”. Please
keep in mind that PP here refers to picture-producer. Depending on which ACT applies,
the DIRECTION is to the inside or outside. This is highly similar to the image schema
CONTAINMENT, which subsumes both directions. For DIRECTION, there is the
additional requirement that it might only connect locations, whereas CONTAIN would be
considered a state, which cannot be mixed. There is no required relation between
CONTAIN and DIRECTION, and it is not necessary that the latter coincide with a container
in either location, start or end.</p>
      <p>CD also explicitly distinguishes objects (animate or inanimate) and persons (per
definition animate) which is not the case for image schemas. Both of these are mapped to
the image schema OBJECT, which could be equalled to PP. As such, some requirements
for INGEST and EXPEL are similar to those of the image schema CONTAINMENT, as
the PP that ACTs as CONTAINer can have one opening (putting food into your mouth),
two openings (breathing through the nose), or several openings (transdermal absorption
into the skin) through which objects or persons can go.</p>
      <p>In the original CD version, MOVE is restricted to the movement of body parts,
which over time has been broadened to denote also the movement of parts of PPs. In
contrast, the general motion entailing a change of location is modeled as PTRANS. For
instance, “John placed his hand over his mouth” falls into the former category of
primitives, whereas “John went home” requires the latter. The change of location for INGEST
and EXPEL ACTs is from the inside to the outside or vice versa. This type of movement
requires a PP, a DIRECTION, and an instrument, which is not further specified by CD. In
the interpretation of this paper we consider the instrument either as a second PP utilized
to cause the movement (e.g. a vehicle) or a PATH serving as the basis for the movement.</p>
      <p>General requirements in CD foresee modifications of primitives to account for tenses
in language. This corresponds to past, future, negation, start of transition, end of
transition, conditional, continuous, interrogative, timeless, and present [15]. For the sake of
simplicity, we will limit those cases to the ones introduced in Section 3.3.
5. Modeling CD Primitives in ISLM
As the most central element of CD primitives, we need to first establish an equivalence
between picture-producers and OBJECTs based on previous findings presented in
Section 2.3, which we will refer to as OBJECTs in this section since PP will here refer
to RCC proper part from now on. Such OBJECTs can change their locations, which in
line with ISLM we model using QTC (see Section 3.2) MOVEMENT ALONG PATH and
which corresponds to PTRANS.</p>
      <p>On PATH Toward(O1; O2) :=
(O1</p>
      <p>O2 ^ DC(O1; O2))</p>
      <p>In order to model the MOVE CD primitive, which represents animate actors moving
parts of their bodies (e.g. arms or legs, or diaphragm muscles to represent a sentence like
“Amy took a breath”), we need to take into consideration that a body part of an animate
actor is a proper part of their body. For the sake of simplicity, we utilize PP(O1; O2),
where object O1 is a proper part of object O2 and can be a tangential proper part (T PP)
or a non-tangential proper part (NT PP). This allows us to model MOVE as a special case
of MOVEMENT ALONG PATH. It requires three objects, since it concerns the body part
(O1), a body (O2), and an object that the body part moves toward (O3). In special cases,
it is possible that O3 coincides with O2 when the body part is moved towards the body or
represents another PP of the body, such as “John placed his hand over his mouth”, where
PP(O1; O2) ^ PP(O3; O2).</p>
      <p>Move Toward(O1; O2; O3) :=</p>
      <p>One central basic primitive is CONTAIN, which as a state in CD can be modeled
utilizing the static representation of CONTAINMENT in ISLM as suggested by Hedblom
et al. [3]. Like Hedblom et al, we augment ISLM with predicates opening of(op; O) to
represent op is an opening of O, inside of(in; O) representing that in is the inside of O,
and outside of(out; O) representing that out is on the outside of O.</p>
      <p>Contained Inside(O1; O2) :=
inside of(in; O2) ^ PP(O1; in)</p>
      <p>In order to become contained, an object needs to cross the opening of the
container. For instance, when breathing the air might pass into the body through the
opening “mouth”. The definition below shows a close relation between several primitives.
It utilizes On PATH Toward, utilized to model PTRANS above, and Contained Inside,
utilized to model CONTAIN, above.</p>
      <p>Crossing Opening(O1; O2; opening) :=</p>
      <p>opening of(opening; O2) ^
(DC(O1; O2) ^ On PATH Toward(O1; opening)) ^</p>
      <sec id="sec-4-1">
        <title>F(PO(O1; opening))</title>
        <p>Crossing Opening is one important modeling component for INGEST, which is
similar to the inward directed movement of a CONTAINMENT image schema and equivalent
to the Going IN in the ISLM implementation of dynamic CONTAINMENT [3]. The fact
that this modeling reuses the modeling of PTRANS and CONTAIN establishes a direct
connection to INGEST.</p>
        <p>To make this relation between primitives more explicit, we show the CD diagram
on the left and the ISLM definition on the right in Table 4. As can be seen in the ISLM
modeling and the CD diagram, INGEST can be treated as a composition of PTRANS
and CONTAIN, if the DIRECTION is modeled as in ISLM. It could be argued that the
explicit Crossing Opening is missing in this case, however, in the CD diagram, this is
also missing for INGEST. Thus, ISLM not only facilitates the detection of CD primitive
interrelations but also fosters a higher precision in their definitions.</p>
        <p>In Table 5, we perform the same modeling exercise for the CD primitive EXPEL,
which equally can be viewed as a composition of PTRANS, CONTAIN, and
DIREC/ CONTAIN(Amy)</p>
        <p>Going IN(air; Amy; mouth) :=
Crossing Opening(air; Amy; mouth) ^</p>
        <p>F(Contained Inside(air; Amy))</p>
        <p>Going IN(air; Amy; mouth) :=
Crossing Opening(air; Amy; mouth) ^</p>
        <p>F(Contained Inside(air; Amy))
TION with the only difference of a change of direction in CD. As can be seen in
Table 5, the same ISLM elements are being used for Going OUT as for Going IN with the
addition of the final state being outside.</p>
        <p>In the previously established correspondences between CD primitives and
imageschematic constructs, INGEST and EXPEL were mapped to CONTAINMENT and
SOURCE PATH GOAL. With ISLM we could now show that in fact these two are
specific cases of CONTAINMENT, which in order to be dynamic requires movement along
a PATH, a CONTAIN relation and a DIRECTION. Since these are other CD primitives,
INGEST and EXPEL can be modelled utilizing compositions of PTRANS, CONTAIN,
and DIRECTION, which further reduces the CD inventory.</p>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>6. Conclusion</title>
      <p>In this paper, we evaluated the formal modeling of Conceptual Dependency primitives,
with the objective of allowing for a more fine-grained comparison and detection of
potential redundancies. Since a previous correspondence to image schemas was established,
we decided to utilize the well-defined Image Schema Logic ISLM, which turned out to be
well applicable to the modeling of CD primitives. This modeling exercise allowed us to
establish an equivalence between INGEST and EXPEL with the only difference of their
DIRECTION, and also show that both could be modeled as a composition of PTRANS,
CONTAIN, and DIRECTION, which means they could be considered redundant. Since
this was only a first experiment on a limited set of primitives, in the future we want to
extend the formalization the full CD repository, which might bring further equivalences
among primitives but also to image schemas to the light.</p>
      <p>Michelle ks</p>
      <sec id="sec-5-1">
        <title>3+ EXPEL o</title>
      </sec>
      <sec id="sec-5-2">
        <title>Michelle ks 3+ PTRANS o</title>
        <p>TJ</p>
        <p>r
lunch jt</p>
        <p>2018.
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