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Representation of Actions as an Interlingua. Karin Kipper & Martha Palmer. Presented in CIS630 by Sriram Venkatapathy. Framework. Animation Performed by a Human Agent. Command In Natural Language (“open a door”). Primary Goal. Animation Performed by a Human Agent. Command In
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Representation of Actions as an Interlingua Karin Kipper & Martha Palmer Presented in CIS630 by Sriram Venkatapathy
Framework Animation Performed by a Human Agent Command In Natural Language (“open a door”)
Primary Goal Animation Performed by a Human Agent Command In Natural Language (“open a door”) Bridge the Gap
Parametrized Action Representation (PAR) • Used to bridge the gap between the command and the animation performed by the virtual human agent. • PARs make explicit many details that are underspecified in the human language.
PARs as an Interlingua • This detailed representation is well suited for an interlingua for MT applications because • Animations of Actions – and therefore the PARs that control them – will be equivalent for the same actions described in different languages.
PARs as an interlingua – contd. Spanish instruction English instruction PARs Animation
PAR • Action’s participants (agent and objects) • Kinematic Properties like its path, manner and duration.
PAR – contd. • Traditional state-space properties of actions such as applicability conditions and preparatory actions. • Termination and Post assertions which determine when an action is concluded.
Hierarchy of actions • Verbs can be represented in a lattice that allows semantically similar verbs, such as motion verbs or verbs of contact, to be closely associated. • A common parent captures the properties that these verbs all share.
Representation of “hammer” • Inherits PAR of hit , and ultimately the PAR • for contact. • with “forceful” manner. • and “hammer” as an instrument.
PAR – contd. • PAR is intended to provide slots for information that is typically conveyed in modifiers or adjuncts. • “John hit the ball” • “John hit the ball with a bat” • “John swung mightily and his bat hit the ball with a resounding sound”. • All map to the same PAR schema.
Deriving the PAR schema • Synchronous Tree-adjoining grammar is used for parsing natural language instructions and obtaining the predicate-argument dependencies. • Assemble the corresponding schemas, and fill in the participants and modifiers to output the PAR schema.
Planner • These schemas might be underspecified for actions like “enter”, “put” and hence don’t have enough information for the animation. • So, a planner is used to • Select the way (activity) “enter by walking/swimming” • Determine preparatory actions “open the door” • Decompose complex actions “put the glass on the table”
PAR as Interlingua • PAR representation is a general template. • It includes properties of the action that can occur linguistically either as the main verb or as adjuncts to the main verb phrase. • Captures divergences such as, for verb-framed versus satellite-framed languages.
Verb-Framed vs Satellite-Framed • Satellite-Framed (English) • Manner -> Main verb. • Motion (path or path + ground location) -> Satellite • Ex. The bottle floated out. • Verb-Framed (Spanish) • Motion -> Main verb • Manner -> Satellite • Ex. La bottella salio flotanda. (the bottle exited floating)
Verb-Framed vs Satellite-Framed • For the sentences, • The bottle floated into the cave. (English) • La bottella entro flotanda a la cueva (Spanish) • (The bottled entered floating the cave)
Verb-Framed vs Satellite-Framed • The PAR schemes don’t distinguish the representation for these sentences, because there is a single schema that includes both the manner and the path without specifying how they are realised linguistically. • EN float/[par:motion,activity:float] into/[term:in(AG,OBJ] • SP entrar/[par:motion,term:in(AG,OBJ) flotar/[activity:float]
Comparison with other work • Considerably different from the approach • outlined in Palmer et al. (1998) which discusses • the use of Feature-based Tree-adjoining • grammars. • It was a transfer-based mechanism expressed • in Synchronous TAG to capture divergences in • VFL and SFL through the use of semantic • features and links between the grammars.
Comparison with other work • Similar to Lexical Conceptual Structures (LCS) • approach. • LCS allows the separation of the concepts of • motion, direction, and manner of motion in the • sentence “John swam across the lake”. • (represented as GO,PATH,MANNER). • This approach allows for a similar representation • and the end result is the same.
Conclusions • This work discusses a parameterized • representation of actions grounded by needs • of animations in a simulated environment. • Generalizations based on action classes • provide the basis for an interlingua approach • that captures the semantics without committing • to any language-dependent specification. • The PAR schema incorporates in a single • template both VFL and SFL languages.