453,529 research outputs found

    ModÚles syntaxiques probabilistes non-génératifs

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    This work deals with models used, or usable in the domain of Automatic Natural Language Processing, when one seeks a syntactic interpretation of a statement. This interpretation can be used as additional information for subsequent treatments, that can aim for instance at producing a semantic representation of the statement. It can also be used as a filter to select utterances belonging to a specific language, among several hypotheses, as done in Automatic Speech Recognition. As the syntactic interpretation of a statement is generally ambiguous with natural languages, the probabilisation of the space of syntactic trees can help in the analysis task : when several analyses are competing, one can then extract the most probable interpretation, or classify interpretations according to their probabilities. We are interested here in the probabilistic versions of Context-Free Grammars (PCFGs) and Substitution Tree Grammar (PTSGs). Syntactic treebanks, which as much as possible account for the language we wish to model, serve as the basis for defining the probabilistic parameters of such grammars. First, we exhibit in this thesis some drawbacks of the usual learning paradigms, due to the use of arbitrary heuristics (STSG DOP model), or to the use of learning criteria that consider these grammars as generative ones (creation of sentences from the grammar) rather than dedicated to analysis (creation of analyses from the sentence). In a second time, we propose new methods for training grammars, based on the traditional Maximum Entropy and Maximum Likelihood criteria. These criteria are instanciated so that they correspond to a syntactic analysis task rather than a language generation task. Specific training algorithms are necessary for their implementation, but traditional algorithms can cope with those models for the task of syntactic analysis. Lastly, we invest the problem of time complexity of syntactic analysis, which is a real issue for the effective use of PTSGs. We describe classes of PTSGs that allow the analysis of a sentence in polynomial complexity. We finally describe a method that enable the extraction of such a PTSG from the set of subtrees of a treebank. The PTSG produced by this method allows us to test our non-generative learning criterium on "realistic" data, and to give a statistical comparison between this criterium and the usual heuristic criterium in term of analysis performance

    Using dialogue to learn math in the LeActiveMath project

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    We describe a tutorial dialogue system under development that assists students in learning how to differentiate equations. The system uses deep natural language understanding and generation to both interpret students ’ utterances and automatically generate a response that is both mathematically correct and adapted pedagogically and linguistically to the local dialogue context. A domain reasoner provides the necessary knowledge about how students should approach math problems as well as their (in)correctness, while a dialogue manager directs pedagogical strategies and keeps track of what needs to be done to keep the dialogue moving along.

    Ontology-based semantic interpretation of cylindricity specification in the next-generation GPS

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    Cylindricity specification is one of the most important geometrical specifications in geometrical product development. This specification can be referenced from the rules and examples in tolerance standards and technical handbooks in practice. These rules and examples are described in the form of natural language, which may cause ambiguities since different designers may have different understandings on a rule or an example. To address the ambiguous problem, a categorical data model of cylindricity specification in the next-generation Geometrical Product Specifications (GPS) was proposed at the University of Huddersfield. The modeling language used in the categorical data model is category language. Even though category language can develop a syntactically correct data model, it is difficult to interpret the semantics of the cylindricity specification explicitly. This paper proposes an ontology-based approach to interpret the semantics of cylindricity specification on the basis of the categorical data model. A scheme for translating the category language to the OWL 2 Web Ontology Language (OWL 2) is presented in this approach. Through such a scheme, the categorical data model is translated into a semantically enriched model, i.e. an OWL 2 ontology for cylindricity specification. This ontology can interpret the semantics of cylindricity specification explicitly. As the benefits of such semantic interpretation, consistency checking, inference procedures and semantic queries can be performed on the OWL 2 ontology. The proposed approach could be easily extended to support the semantic interpretations of other kinds of geometrical specifications

    Using a Logic Programming Framework to Control Database Query Dialogues in Natural Language

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    We present a natural language question/answering system to interface the University of Évora databases that uses clarification dialogs in order to clarify user questions. It was developed in an integrated logic programming framework, based on constraint logic programming using the GnuProlog(-cx) language [2,11] and the ISCO framework [1]. The use of this LP framework allows the integration of Prolog-like inference mechanisms with classes and inheritance, constraint solving algorithms and provides the connection with relational databases, such as PostgreSQL. This system focus on the questions’ pragmatic analysis, to handle ambiguity, and on an efficient dialogue mechanism, which is able to place relevant questions to clarify the user intentions in a straightforward manner. Proper Nouns resolution and the pp-attachment problem are also handled. This paper briefly presents this innovative system focusing on its ability to correctly determine the user intention through its dialogue capability

    Multimodal Grounding for Language Processing

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    This survey discusses how recent developments in multimodal processing facilitate conceptual grounding of language. We categorize the information flow in multimodal processing with respect to cognitive models of human information processing and analyze different methods for combining multimodal representations. Based on this methodological inventory, we discuss the benefit of multimodal grounding for a variety of language processing tasks and the challenges that arise. We particularly focus on multimodal grounding of verbs which play a crucial role for the compositional power of language.Comment: The paper has been published in the Proceedings of the 27 Conference of Computational Linguistics. Please refer to this version for citations: https://www.aclweb.org/anthology/papers/C/C18/C18-1197
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