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An Efficient Implementation of the HeadCorner Parser
 COMPUTATIONAL LINGUISTICS
, 1996
"... This paper describes an efficient and robust implementation of a bidirectional, headdriven parser for constraintbased grammars. This parser is developed for the OVIS system: a Dutch spoken dialogue system in which information about public transport can be obtained by telephone. After a Review ..."
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Cited by 36 (2 self)
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This paper describes an efficient and robust implementation of a bidirectional, headdriven parser for constraintbased grammars. This parser is developed for the OVIS system: a Dutch spoken dialogue system in which information about public transport can be obtained by telephone. After a Review
Head Corner Parsing for TAG
 Computational Intelligence
, 1994
"... This paper describes a bidirectional headcorner parser for (unificationbased versions of) Lexicalized Tree Adjoining Grammars. Keywords: headdriven parsing, bidirectional parsing, Tree Adjoining Grammar. 1 Introduction Natural language parsing is still inefficient. There are two important reason ..."
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Cited by 25 (2 self)
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This paper describes a bidirectional headcorner parser for (unificationbased versions of) Lexicalized Tree Adjoining Grammars. Keywords: headdriven parsing, bidirectional parsing, Tree Adjoining Grammar. 1 Introduction Natural language parsing is still inefficient. There are two important reasons for this. Natural language contains many ambiguities which lead to a large search space for parsers. On the other hand the complex structure of natural language is problematic; natural language parsers usually are based on grammars of which the formal power goes beyond the contextfree grammars. Both observations imply that efficient algorithms that have been developed for e.g. programming languages, such as LR(1), can not be used as such. To obtain a parsing algorithm for a class of grammars beyond the contextfree grammars, the usual strategy is to generalize an efficient algorithm for contextfree grammars to this more powerful class. The problem with this approach is that in the course...
Bidirectional Parsing Of Lexicalized Tree Adjoining Grammars
, 1991
"... In this paper a bidirectional parser for Lexicalized Tree Adjoining Grammars will be presented. The algorithm takes advantage of a peculiar characteristic of Lexicalized TAGs, i.e. that each elementary tree is associated with a lexical item, called its anchor. The algorithm employs a mixed strategy: ..."
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Cited by 22 (1 self)
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In this paper a bidirectional parser for Lexicalized Tree Adjoining Grammars will be presented. The algorithm takes advantage of a peculiar characteristic of Lexicalized TAGs, i.e. that each elementary tree is associated with a lexical item, called its anchor. The algorithm employs a mixed strategy: it works bottom up from the lexical anchors and then expands (.partial) analyses making topdown predictions. Even if such an algorithm does not improve the worstcase time bounds of already known TAGs parsing methods, it could be relevant from the perspective of linguistic information processing, because it employs lexical information in a more direct way.
An Extended Theory Of HeadDriven Parsing
 Mexico State University
, 1994
"... We show that more headdriven parsing algorithms can be formulated than those occurring in the existing literature. These algorithms are inspired by a family of lefttoright parsing algorithms from a recent publica tion. We further introduce a more advanced notion of "headdriven parsing" which al ..."
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Cited by 10 (7 self)
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We show that more headdriven parsing algorithms can be formulated than those occurring in the existing literature. These algorithms are inspired by a family of lefttoright parsing algorithms from a recent publica tion. We further introduce a more advanced notion of "headdriven parsing" which allows more detailed specification of the processing order of nonhead elements in the righthand side. We develop a parsing algorithm for this strategy, based on LR parsing techniques.
Parsing Schemata and Correctness of Parsing Algorithms
 Theoretical Computer Science
, 1998
"... Parsing schemata provide a highlevel formal description of parsers. These can be used, among others, as an intermediate level of abstraction for deriving the formal correctness of a parser. A parser is correct if it duely implements a parsing schema that is known to be correct. In this paper it is ..."
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Cited by 8 (0 self)
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Parsing schemata provide a highlevel formal description of parsers. These can be used, among others, as an intermediate level of abstraction for deriving the formal correctness of a parser. A parser is correct if it duely implements a parsing schema that is known to be correct. In this paper it is discussed how the correctness of a parsing schema can be proven and how parsing schemata relate to some wellknown classes of parsers, viz. chart parsers and LRtype parsers.
Conventional Natural Language Processing in the NWO Priority Programme on Language and Speech Technology
, 1996
"... ..."
How to Compare the Structure of Parsing Algorithms
 In: Pighizzini G., San Pietro P. (Eds.), Proc. ASMICS Workshop on Parsing Theory
, 1994
"... Parsing schemata are defined as an intermediate level of abstraction between contextfree grammars and parsers. Clear, concise specifications of radically different parsing algorithms can be expressed as parsing schemata. Moreover, because of the uniformity of these specifications, relations between ..."
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Cited by 5 (1 self)
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Parsing schemata are defined as an intermediate level of abstraction between contextfree grammars and parsers. Clear, concise specifications of radically different parsing algorithms can be expressed as parsing schemata. Moreover, because of the uniformity of these specifications, relations between different parsing algorithms can be formally established. This article gives an introduction to the parsing schemata framework. 1 Introduction A wide variety of parsing algorithms can be found in the Computer Science and Computational Linguistics literature. Algorithms differ a lot with respect to languages in which they are expressed, data structures used, degree of formality, class of grammars that can be handled, etc. Things get worse when we consider parallel, rather than sequential algorithms, because many different architectures can be exploited. One can compare parsers by evaluating runtime performance, but in order to get a deeper insight into the relative merits and deficiencies o...
Predictive HeadCorner Chart Parsing
, 1993
"... HeadCorner (HC) parsing has come up in computational linguistics a few years ago, motivated by linguistic arguments. This idea is a heuristic, rather than a failsafe principle, hence it is relevant indeed to consider the worstcase behaviour of the HC parser. We define a novel predictive headcorn ..."
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Cited by 1 (0 self)
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HeadCorner (HC) parsing has come up in computational linguistics a few years ago, motivated by linguistic arguments. This idea is a heuristic, rather than a failsafe principle, hence it is relevant indeed to consider the worstcase behaviour of the HC parser. We define a novel predictive headcorner chart parser of cubic time complexity. We start with a leftcorner (LC) chart parser, which is easier to understand. Subsequently, the LC chart parser is generalized to an HC chart parser. It is briefly sketched how the parser can be enhanced with feature structures. 1. Introduction "Our Latin teachers were apparently right", Martin Kay (1989) remarks. "You should start [parsing] with the main verb. This will tell you what kinds of subjects and objects to look for and what cases they will be in. When you come to look for these, you should also start by trying to find the main word, because this will tell you most about what else to look for". Headdriven or headcorner parsing has been ...
Robust Efficient Parsing for Spoken Dialogue Processing
, 1998
"... ion (Johnson and Dorre, [39]) ffl x(A,B,f(A,B),g(A,h(B,i(C)))) =) x(A,B,f(,),g(,)) ffl parsewithweakening(Cat,P0,P,E0,E) : weaken(Cat,WeakenedCat), parse(WeakenedCat,P0,P,E0,E), Cat=WeakenedCat. ffl Really helps! Ambiguity Packing ffl A parser should not construct all parse trees (exponential) ..."
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ion (Johnson and Dorre, [39]) ffl x(A,B,f(A,B),g(A,h(B,i(C)))) =) x(A,B,f(,),g(,)) ffl parsewithweakening(Cat,P0,P,E0,E) : weaken(Cat,WeakenedCat), parse(WeakenedCat,P0,P,E0,E), Cat=WeakenedCat. ffl Really helps! Ambiguity Packing ffl A parser should not construct all parse trees (exponential) ffl Instead, a compact representation of all such parse trees are constructed  grammar [42, 9]  parse forest [76]  packed structures [3] ffl Here: for every `result item' keep track of the lexical entry and references of other result items that were used to create it ffl Results in a lexicalized tree substitution grammar ffl which generates the input sentence with all its parse trees Bottomup Inactivechart Parser Item form: [i;X; j] Axioms: Goals: [0;S;n] Inference Rules: Scan [q i ;wi; qi+1 ] Complete [q k ;X1; q k 0][q k 0;X2; q k 00] : : : [q m0;Xl; qm] [q k ;X0; qm] X0 !X1:::Xl Bottomup Inactivechart Parser Inference Rules: Scan [q i ;wi; qi+...