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Finitestate multimodal parsing and understanding
 In Proceedings of COLING 2000
, 2000
"... Multimodal interfaces require effective parsing and understanding of utterances whose content is distributed across multiple input modes. Johnston 1998 presents an approach in which strategies for multimodal integration are stated declaratively using a unificationbased grammar that is used by a mul ..."
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Cited by 57 (14 self)
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Multimodal interfaces require effective parsing and understanding of utterances whose content is distributed across multiple input modes. Johnston 1998 presents an approach in which strategies for multimodal integration are stated declaratively using a unificationbased grammar that is used by a multidimensional chart parser to compose inputs. This approach is highly expressive and supports a broad class of interfaces, but offers only limited potential for mutual compensation among the input modes, is subject to significant concerns in terms of computational complexity, and complicates selection among alternative multimodal interpretations of the input. In this paper, we present an alternative approach in which multimodal parsing and understanding are achieved using a weighted finitestate device which takes speech and gesture streams as inputs and outputs their joint interpretation. This approach is significantly more efficient, enables tightcoupling of multimodal understanding with speech recognition, and provides a general probabilistic framework for multimodal ambiguity resolution. 1
Regular Approximation Of ContextFree Grammars Through Transformation
, 2000
"... We present an algorithm for approximating contextfree languages with regular languages. The algorithm is based on a simple transformation that applies to any contextfree grammar and guarantees that the result can be compiled into a finite automaton. The resulting grammar contains at most one new n ..."
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Cited by 36 (4 self)
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We present an algorithm for approximating contextfree languages with regular languages. The algorithm is based on a simple transformation that applies to any contextfree grammar and guarantees that the result can be compiled into a finite automaton. The resulting grammar contains at most one new nonterminal for any nonterminal symbol of the input grammar. The result thus remains readable and if necessary modifiable. We extend the approximation algorithm to the case of weighted contextfree grammars. We also report experiments with several grammars showing that the size of the minimal deterministic automata accepting the resulting approximations is of practical use for applications such as speech recognition. 9.1 Introduction Despite the availability of extensive literature on the topic of efficient contextfree parsing, for large and very ambiguous grammars, contextfree parsing poses a serious problem in many practical applications such as realtime speech recognition. For most gra...
Practical Experiments with Regular Approximation Of ContextFree Languages
 Computational Linguistics
, 2000
"... this article we will try to answer the above two questions in a practical setting, using practical linguistic grammars and sentences taken from a spokenlanguage corpus ..."
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Cited by 29 (2 self)
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this article we will try to answer the above two questions in a practical setting, using practical linguistic grammars and sentences taken from a spokenlanguage corpus
Robust probabilistic predictive syntactic processing: Motivations, models, and applications. Doctoral dissertation, Brown University. (UMI: AAT 3006783
 Carnegie Mellon University
, 2001
"... 2001 This thesis by Brian E. Roark is accepted in its present form by ..."
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Cited by 11 (0 self)
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2001 This thesis by Brian E. Roark is accepted in its present form by
Removing Left Recursion from ContextFree Grammars
, 2000
"... contextfree grammars (CFGs) in a "topdown " lefttoright fashion is that left recursion can lead to nontermination. An algorithm is known that transforms any CFG into an equivalent nonleft recursive CFG, but the resulting grammars are often too large for practical use. We present a new method for ..."
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Cited by 9 (0 self)
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contextfree grammars (CFGs) in a "topdown " lefttoright fashion is that left recursion can lead to nontermination. An algorithm is known that transforms any CFG into an equivalent nonleft recursive CFG, but the resulting grammars are often too large for practical use. We present a new method for removing left recursion from CFGs that is both theoretically superior to the standard algorithm, and produces very compact nonleftrecursive CFGs in practice.
The treatment of epsilon moves in subset construction
 IN FINITESTATE METHODS IN NATURAL LANGUAGE PROCESSING, ANKARA. CMPLG/9804003
, 1998
"... The paper discusses the problem of determinizing finitestate automata containing large numbers of εmoves. Experiments with finitestate approximations of natural language grammars often give rise to very large automata with a very large number of εmoves. The paper identifies and compares a number ..."
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Cited by 7 (2 self)
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The paper discusses the problem of determinizing finitestate automata containing large numbers of εmoves. Experiments with finitestate approximations of natural language grammars often give rise to very large automata with a very large number of εmoves. The paper identifies and compares a number of subset construction algorithms that treat εmoves. Experiments have been performed which indicate that the algorithms differ considerably in practice, both with respect to the size of the resulting deterministic automaton, and with respect to practical efficiency. Furthermore, the experiments suggest that the average number of εmoves per state can be used to predict which algorithm is likely to be the fastest for a given input automaton.
Typed Transformations of Typed Abstract Syntax
, 2008
"... Advantages of embedded domainspecific languages (EDSLs) are that one does not have to implement a separate type system nor an abstraction mechanism, since these are directly borrowed from the host language. Straightforward implementations of embedded domainspecific languages map the semantics of t ..."
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Cited by 7 (2 self)
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Advantages of embedded domainspecific languages (EDSLs) are that one does not have to implement a separate type system nor an abstraction mechanism, since these are directly borrowed from the host language. Straightforward implementations of embedded domainspecific languages map the semantics of the embedded language onto a function in the host language. The semantic mappings are usually compositional, i.e. they directly follow the syntax of the embedded language. One of the questions which arises is whether conventional compilation techniques, such as global analysis and resulting transformations, can be applied in the context of EDSLs. The approach we take is that, instead of mapping the embedded language directly onto a function, we first build a representation of the abstract syntax tree of the embedded program fragment. This syntax tree is subsequently analyzed and transformed, and finally mapped onto a function representing its denotational semantics. In this way we achieve an online compilation of the embedded language. We show how to use typed abstract syntax to represent fragments of embedded programs containing variables and binding structures while preserving the idea that the type system of the host language is used to emulate the type system of the embedded language. The tricky issue is how to keep mutually recursive structures welltyped while being transformed. For this we develop an arrowlike library which assists in implementing such analyses and transformations and show its usefulness in describing leftrecursion removal of an embedded grammar expressed with parser combinators using the LeftCorner Transform.
Dependently Typed Grammars
"... Abstract. Parser combinators are a popular tool for designing parsers in functional programming languages. If such combinators generate an abstract representation of the grammar as an intermediate step, it becomes easier to perform analyses and transformations that can improve the behaviour of the r ..."
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Cited by 3 (0 self)
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Abstract. Parser combinators are a popular tool for designing parsers in functional programming languages. If such combinators generate an abstract representation of the grammar as an intermediate step, it becomes easier to perform analyses and transformations that can improve the behaviour of the resulting parser. Grammar transformations must satisfy a number of invariants. In particular, they have to preserve the semantics associated with the grammar. Using conventional type systems, these constraints cannot be expressed satisfactorily, but as we show in this article, dependent types are a natural fit. We present a framework for grammars and grammar transformations using Agda. We implement the leftcorner transformation for leftrecursion removal and prove a languageinclusion property as use cases. Key words: contextfree grammars, grammar transformation, dependently typed programming 1
Compounding and Derivational Morphology in a FiniteState Setting
, 2003
"... This paper proposes the application of finitestate approximation techniques on a unificationbased grammar of word formation for a language like German. A refinement of an RTNbased approximation algorithm is proposed, which extends the state space of the automaton by selectively adding dist ..."
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This paper proposes the application of finitestate approximation techniques on a unificationbased grammar of word formation for a language like German. A refinement of an RTNbased approximation algorithm is proposed, which extends the state space of the automaton by selectively adding distinctions based on the parsing history at the point of entering a contextfree rule. The selection of history items exploits the specific linguistic nature of word formation. As experiments show, this algorithm avoids an explosion of the size of the automaton in the approximation construction.
Removing Left Recursion from ContextFree Grammars
, 2000
"... contextfree grammars (CFGs) in a "topdown" leftto right fashion is that left recursion can lead to nontermination. An algorithm is known that transforms any CFG into an equivalent nonleftrecursive CFG, but the resulting grammars are often too large for practical use. We present a new method for ..."
Abstract
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contextfree grammars (CFGs) in a "topdown" leftto right fashion is that left recursion can lead to nontermination. An algorithm is known that transforms any CFG into an equivalent nonleftrecursive CFG, but the resulting grammars are often too large for practical use. We present a new method for removing left recursion from CFGs that is both theoretically superior to the standard algorithm, and produces very compact nonleftrecursive CFGs in practice.