tailieunhanh - Báo cáo khoa học: "UNDERSTANDING NATURAL LANGUAGE INSTRUCTIONS: THE CASE OF PURPOSE CLAUSES"

This paper presents an analysis of purpose clauses in the context of instruction understanding. Such analysis shows that goals affect the interpretation and / or execution of actions, lends support to the proposal of using generation and enablement to model relations between actions, and sheds light on some inference processes necessary to interpret purpose clauses. which, as its name says, expresses the agent's purpose in performing a certain action. The analysis of purpose clauses is relevant to the problem of understanding Natural Language instructions, because: . | UNDERSTANDING NATURAL LANGUAGE INSTRUCTIONS THE CASE OF PURPOSE CLAUSES Barbara Di Eugenio Department of Computer and Information Science University of Pennsylvania Philadelphia PA dieugeni@ ABSTRACT This paper presents an analysis of purpose clauses in the context of instruction understanding. Such analysis shows that goals affect the interpretation and I or execution of actions lends support to the proposal of using generation and enablement to model relations between actions and sheds light on some inference processes necessary to interpret purpose clauses. INTRODUCTION À speaker S gives instructions to a hearer H in order to affect H s behavior. Researchers including Winograd 1972 Chapman 1991 Vere and Bick-more 1990 Cohen and Levesque 1990 Alterman et al. 1991 have been and are addressing many complex facets of the problem of mapping Natural Language instructions onto an agent s behavior. However an aspect that no one has really considered is computing the objects of the intentions H s adopts namely the actions to be performed. In general researchers have equated such objects with logical forms extracted from the NL input. This is perhaps sufficient for simple positive imperatives but more complex imperatives require that action descriptions be computed not simply extracted from the input instruction. To clarify my point consider Ex. 1 a Place a plank between two ladders. b Place a plank between two ladders to create a simple scaffold. In both a and b the action to be executed is place a plank between two ladders. However Ex. would be correctly interpreted by placing the plank anywhere between the two ladders this shows that in b H must be inferring the proper position for the plank from the expressed goal to create a simple scaffold. Therefore the goal an action is meant to achieve constrains the interpretation and I or the execution of the action itself. The infinitival sentence in Ex. is a purpose clause Mailing address IRCS - 3401