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cmp-lg/9603004
Attempto - From Specifications in Controlled Natural Language towards Executable Specifications
cmp-lg cs.CL
Deriving formal specifications from informal requirements is difficult since one has to take into account the disparate conceptual worlds of the application domain and of software development. To bridge the conceptual gap we propose controlled natural language as a textual view on formal specifications in logic. The ...
cmp-lg/9603005
Integrated speech and morphological processing in a connectionist continuous speech understanding for Korean
cmp-lg cs.CL
A new tightly coupled speech and natural language integration model is presented for a TDNN-based continuous possibly large vocabulary speech recognition system for Korean. Unlike popular n-best techniques developed for integrating mainly HMM-based speech recognition and natural language processing in a {\em word lev...
cmp-lg/9603006
Extraction of V-N-Collocations from Text Corpora: A Feasibility Study for German
cmp-lg cs.CL
The usefulness of a statistical approach suggested by Church et al. (1991) is evaluated for the extraction of verb-noun (V-N) collocations from German text corpora. Some problematic issues of that method arising from properties of the German language are discussed and various modifications of the method are considere...
cmp-lg/9604001
Combining Hand-crafted Rules and Unsupervised Learning in Constraint-based Morphological Disambiguation
cmp-lg cs.CL
This paper presents a constraint-based morphological disambiguation approach that is applicable languages with complex morphology--specifically agglutinative languages with productive inflectional and derivational morphological phenomena. In certain respects, our approach has been motivated by Brill's recent work, bu...
cmp-lg/9604002
A Constraint-based Case Frame Lexicon
cmp-lg cs.CL
We present a constraint-based case frame lexicon architecture for bi-directional mapping between a syntactic case frame and a semantic frame. The lexicon uses a semantic sense as the basic unit and employs a multi-tiered constraint structure for the resolution of syntactic information into the appropriate senses and/...
cmp-lg/9604003
Error-tolerant Tree Matching
cmp-lg cs.CL
This paper presents an efficient algorithm for retrieving from a database of trees, all trees that match a given query tree approximately, that is, within a certain error tolerance. It has natural language processing applications in searching for matches in example-based translation systems, and retrieval from lexica...
cmp-lg/9604004
Apportioning Development Effort in a Probabilistic LR Parsing System through Evaluation
cmp-lg cs.CL
We describe an implemented system for robust domain-independent syntactic parsing of English, using a unification-based grammar of part-of-speech and punctuation labels coupled with a probabilistic LR parser. We present evaluations of the system's performance along several different dimensions; these enable us to ass...
cmp-lg/9604005
Better Language Models with Model Merging
cmp-lg cs.CL
This paper investigates model merging, a technique for deriving Markov models from text or speech corpora. Models are derived by starting with a large and specific model and by successively combining states to build smaller and more general models. We present methods to reduce the time complexity of the algorithm and...
cmp-lg/9604006
The Role of the Gricean Maxims in the Generation of Referring Expressions
cmp-lg cs.CL
Grice's maxims of conversation [Grice 1975] are framed as directives to be followed by a speaker of the language. This paper argues that, when considered from the point of view of natural language generation, such a characterisation is rather misleading, and that the desired behaviour falls out quite naturally if we ...
cmp-lg/9604007
Collocational Grammar
cmp-lg cs.CL
A perspective of statistical language models which emphasizes their collocational aspect is advocated. It is suggested that strings be generalized in terms of classes of relationships instead of classes of objects. The single most important characteristic of such a model is a mechanism for comparing patterns. When pa...
cmp-lg/9604008
Efficient Algorithms for Parsing the DOP Model
cmp-lg cs.CL
Excellent results have been reported for Data-Oriented Parsing (DOP) of natural language texts (Bod, 1993). Unfortunately, existing algorithms are both computationally intensive and difficult to implement. Previous algorithms are expensive due to two factors: the exponential number of rules that must be generated and...
cmp-lg/9604009
Another Facet of LIG Parsing
cmp-lg cs.CL
In this paper we present a new parsing algorithm for linear indexed grammars (LIGs) in the same spirit as the one described in (Vijay-Shanker and Weir, 1993) for tree adjoining grammars. For a LIG $L$ and an input string $x$ of length $n$, we build a non ambiguous context-free grammar whose sentences are all (and exc...
cmp-lg/9604010
Off-line Constraint Propagation for Efficient HPSG Processing
cmp-lg cs.CL
We investigate the use of a technique developed in the constraint programming community called constraint propagation to automatically make a HPSG theory more specific at those places where linguistically motivated underspecification would lead to inefficient processing. We discuss two concrete HPSG examples showing ...
cmp-lg/9604011
Multi-level post-processing for Korean character recognition using morphological analysis and linguistic evaluation
cmp-lg cs.CL
Most of the post-processing methods for character recognition rely on contextual information of character and word-fragment levels. However, due to linguistic characteristics of Korean, such low-level information alone is not sufficient for high-quality character-recognition applications, and we need much higher-leve...
cmp-lg/9604012
SemHe: A Generalised Two-Level System
cmp-lg cs.CL
This paper presents a generalised two-level implementation which can handle linear and non-linear morphological operations. An algorithm for the interpretation of multi-tape two-level rules is described. In addition, a number of issues which arise when developing non-linear grammars are discussed with examples from S...
cmp-lg/9604013
Syntactic Analyses for Parallel Grammars: Auxiliaries and Genitive NPs
cmp-lg cs.CL
This paper focuses on two disparate aspects of German syntax from the perspective of parallel grammar development. As part of a cooperative project, we present an innovative approach to auxiliaries and multiple genitive NPs in German. The LFG-based implementation presented here avoids unnessary structural complexity ...
cmp-lg/9604014
The importance of being lazy -- using lazy evaluation to process queries to HPSG grammars
cmp-lg cs.CL
Linguistic theories formulated in the architecture of {\sc hpsg} can be very precise and explicit since {\sc hpsg} provides a formally well-defined setup. However, when querying a faithful implementation of such an explicit theory, the large data structures specified can make it hard to see the relevant aspects of th...
cmp-lg/9604015
Computing Prosodic Morphology
cmp-lg cs.CL
This paper establishes a framework under which various aspects of prosodic morphology, such as templatic morphology and infixation, can be handled under two-level theory using an implemented multi-tape two-level model. The paper provides a new computational analysis of root-and-pattern morphology based on prosody.
cmp-lg/9604016
Processing Metonymy: a Domain-Model Heuristic Graph Traversal Approach
cmp-lg cs.CL
We address here the treatment of metonymic expressions from a knowledge representation perspective, that is, in the context of a text understanding system which aims to build a conceptual representation from texts according to a domain model expressed in a knowledge representation formalism. We focus in this paper ...
cmp-lg/9604017
Fast Parsing using Pruning and Grammar Specialization
cmp-lg cs.CL
We show how a general grammar may be automatically adapted for fast parsing of utterances from a specific domain by means of constituent pruning and grammar specialization based on explanation-based learning. These methods together give an order of magnitude increase in speed, and the coverage loss entailed by gramma...
cmp-lg/9604018
The Measure of a Model
cmp-lg cs.CL
This paper describes measures for evaluating the three determinants of how well a probabilistic classifier performs on a given test set. These determinants are the appropriateness, for the test set, of the results of (1) feature selection, (2) formulation of the parametric form of the model, and (3) parameter estimat...
cmp-lg/9604019
Magic for Filter Optimization in Dynamic Bottom-up Processing
cmp-lg cs.CL
Off-line compilation of logic grammars using Magic allows an incorporation of filtering into the logic underlying the grammar. The explicit definite clause characterization of filtering resulting from Magic compilation allows processor independent and logically clean optimizations of dynamic bottom-up processing with...
cmp-lg/9604020
Translating into Free Word Order Languages
cmp-lg cs.CL
In this paper, I discuss machine translation of English text into Turkish, a relatively ``free'' word order language. I present algorithms that determine the topic and the focus of each target sentence (using salience (Centering Theory), old vs. new information, and contrastiveness in the discourse model) in order to...
cmp-lg/9604021
Extended Dependency Structures and their Formal Interpretation
cmp-lg cs.CL
We describe two ``semantically-oriented'' dependency-structure formalisms, U-forms and S-forms. U-forms have been previously used in machine translation as interlingual representations, but without being provided with a formal interpretation. S-forms, which we introduce in this paper, are a scoped version of U-forms,...
cmp-lg/9604022
Unsupervised Learning of Word-Category Guessing Rules
cmp-lg cs.CL
Words unknown to the lexicon present a substantial problem to part-of-speech tagging. In this paper we present a technique for fully unsupervised statistical acquisition of rules which guess possible parts-of-speech for unknown words. Three complementary sets of word-guessing rules are induced from the lexicon and a ...
cmp-lg/9604023
A Model-Theoretic Framework for Theories of Syntax
cmp-lg cs.CL
A natural next step in the evolution of constraint-based grammar formalisms from rewriting formalisms is to abstract fully away from the details of the grammar mechanism---to express syntactic theories purely in terms of the properties of the class of structures they license. By focusing on the structural properties ...
cmp-lg/9604024
Connectivity in Bag Generation
cmp-lg cs.CL
This paper presents a pruning technique which can be used to reduce the number of paths searched in rule-based bag generators of the type proposed by \cite{poznanskietal95} and \cite{popowich95}. Pruning the search space in these generators is important given the computational cost of bag generation. The technique re...
cmp-lg/9604025
Learning Part-of-Speech Guessing Rules from Lexicon: Extension to Non-Concatenative Operations
cmp-lg cs.CL
One of the problems in part-of-speech tagging of real-word texts is that of unknown to the lexicon words. In Mikheev (ACL-96 cmp-lg/9604022), a technique for fully unsupervised statistical acquisition of rules which guess possible parts-of-speech for unknown words was proposed. One of the over-simplification assumed ...
cmp-lg/9604026
Towards a Workbench for Acquisition of Domain Knowledge from Natural Language
cmp-lg cs.CL
In this paper we describe an architecture and functionality of main components of a workbench for an acquisition of domain knowledge from large text corpora. The workbench supports an incremental process of corpus analysis starting from a rough automatic extraction and organization of lexico-semantic regularities and...
cmp-lg/9605001
Compiling a Partition-Based Two-Level Formalism
cmp-lg cs.CL
This paper describes an algorithm for the compilation of a two (or more) level orthographic or phonological rule notation into finite state transducers. The notation is an alternative to the standard one deriving from Koskenniemi's work: it is believed to have some practical descriptive advantages, and is quite widel...
cmp-lg/9605002
Building Natural-Language Generation Systems
cmp-lg cs.CL
This is a very short paper that briefly discusses some of the tasks that NLG systems perform. It is of no research interest, but I have occasionally found it useful as a way of introducing NLG to potential project collaborators who know nothing about the field.
cmp-lg/9605003
Yet Another Paper about Partial Verb Phrase Fronting in German
cmp-lg cs.CL
I describe a very simple HPSG analysis for partial verb phrase fronting. I will argue that the presented account is more adequate than others made during the past years because it allows the description of constituents in fronted positions with their modifier remaining in the non-fronted part of the sentence. A probl...
cmp-lg/9605004
Higher-Order Coloured Unification and Natural Language Semantics
cmp-lg cs.CL
In this paper, we show that Higher-Order Coloured Unification - a form of unification developed for automated theorem proving - provides a general theory for modeling the interface between the interpretation process and other sources of linguistic, non semantic information. In particular, it provides the general theo...
cmp-lg/9605005
Focus and Higher-Order Unification
cmp-lg cs.CL
Pulman has shown that Higher--Order Unification (HOU) can be used to model the interpretation of focus. In this paper, we extend the unification--based approach to cases which are often seen as a test--bed for focus theory: utterances with multiple focus operators and second occurrence expressions. We then show that ...
cmp-lg/9605006
Active Constraints for a Direct Interpretation of HPSG
cmp-lg cs.CL
In this paper, we characterize the properties of a direct interpretation of HPSG and present the advantages of this approach. High-level programming languages constitute in this perspective an efficient solution: we show how a multi-paradigm approach, containing in particular constraint logic programming, offers mech...
cmp-lg/9605007
Resolving Anaphors in Embedded Sentences
cmp-lg cs.CL
We propose an algorithm to resolve anaphors, tackling mainly the problem of intrasentential antecedents. We base our methodology on the fact that such antecedents are likely to occur in embedded sentences. Sidner's focusing mechanism is used as the basic algorithm in a more complete approach. The proposed algorithm h...
cmp-lg/9605008
Tactical Generation in a Free Constituent Order Language
cmp-lg cs.CL
This paper describes tactical generation in Turkish, a free constituent order language, in which the order of the constituents may change according to the information structure of the sentences to be generated. In the absence of any information regarding the information structure of a sentence (i.e., topic, focus, ba...
cmp-lg/9605009
Learning similarity-based word sense disambiguation from sparse data
cmp-lg cs.CL
We describe a method for automatic word sense disambiguation using a text corpus and a machine-readable dictionary (MRD). The method is based on word similarity and context similarity measures. Words are considered similar if they appear in similar contexts; contexts are similar if they contain similar words. The cir...
cmp-lg/9605010
Best-First Surface Realization
cmp-lg cs.CL
Current work in surface realization concentrates on the use of general, abstract algorithms that interpret large, reversible grammars. Only little attention has been paid so far to the many small and simple applications that require coverage of a small sublanguage at different degrees of sophistication. The system TG...
cmp-lg/9605011
Counting Coordination Categorially
cmp-lg cs.CL
This paper presents a way of reducing the complexity of parsing free coordination. It lives on the Coordinative Count Invariant, a property of derivable sequences in occurrence-sensitive categorial grammar. This invariant can be exploited to cut down deterministically the search space for coordinated sentences to min...
cmp-lg/9605012
A New Statistical Parser Based on Bigram Lexical Dependencies
cmp-lg cs.CL
This paper describes a new statistical parser which is based on probabilities of dependencies between head-words in the parse tree. Standard bigram probability estimation techniques are extended to calculate probabilities of dependencies between pairs of words. Tests using Wall Street Journal data show that the metho...
cmp-lg/9605013
Learning Dependencies between Case Frame Slots
cmp-lg cs.CL
We address the problem of automatically acquiring case frame patterns (selectional patterns) from large corpus data. In particular, we propose a method of learning dependencies between case frame slots. We view the problem of learning case frame patterns as that of learning multi-dimensional discrete joint distributi...
cmp-lg/9605014
Clustering Words with the MDL Principle
cmp-lg cs.CL
We address the problem of automatically constructing a thesaurus (hierarchically clustering words) based on corpus data. We view the problem of clustering words as that of estimating a joint distribution over the Cartesian product of a partition of a set of nouns and a partition of a set of verbs, and propose an esti...
cmp-lg/9605015
Adapting the Core Language Engine to French and Spanish
cmp-lg cs.CL
We describe how substantial domain-independent language-processing systems for French and Spanish were quickly developed by manually adapting an existing English-language system, the SRI Core Language Engine. We explain the adaptation process in detail, and argue that it provides a fairly general recipe for convertin...
cmp-lg/9605016
Parsing for Semidirectional Lambek Grammar is NP-Complete
cmp-lg cs.CL
We study the computational complexity of the parsing problem of a variant of Lambek Categorial Grammar that we call {\em semidirectional}. In semidirectional Lambek calculus $\SDL$ there is an additional non-directional abstraction rule allowing the formula abstracted over to appear anywhere in the premise sequent's ...
cmp-lg/9605017
A Chart Generator for Shake and Bake Machine Translation
cmp-lg cs.CL
A generation algorithm based on an active chart parsing algorithm is introduced which can be used in conjunction with a Shake and Bake machine translation system. A concise Prolog implementation of the algorithm is provided, and some performance comparisons with a shift-reduce based algorithm are given which show the...
cmp-lg/9605018
Efficient Tabular LR Parsing
cmp-lg cs.CL
We give a new treatment of tabular LR parsing, which is an alternative to Tomita's generalized LR algorithm. The advantage is twofold. Firstly, our treatment is conceptually more attractive because it uses simpler concepts, such as grammar transformations and standard tabulation techniques also know as chart parsing....
cmp-lg/9605019
Noun-Phrase Analysis in Unrestricted Text for Information Retrieval
cmp-lg cs.CL
Information retrieval is an important application area of natural-language processing where one encounters the genuine challenge of processing large quantities of unrestricted natural-language text. This paper reports on the application of a few simple, yet robust and efficient noun-phrase analysis techniques to crea...
cmp-lg/9605020
Where Defaults Don't Help: the Case of the German Plural System
cmp-lg cs.CL
The German plural system has become a focal point for conflicting theories of language, both linguistic and cognitive. We present simulation results with three simple classifiers - an ordinary nearest neighbour algorithm, Nosofsky's `Generalized Context Model' (GCM) and a standard, three-layer backprop network - pred...
cmp-lg/9605021
Functional Centering
cmp-lg cs.CL
Based on empirical evidence from a free word order language (German) we propose a fundamental revision of the principles guiding the ordering of discourse entities in the forward-looking centers within the centering model. We claim that grammatical role criteria should be replaced by indicators of the functional info...
cmp-lg/9605022
Processing Complex Sentences in the Centering Framework
cmp-lg cs.CL
We extend the centering model for the resolution of intra-sentential anaphora and specify how to handle complex sentences. An empirical evaluation indicates that the functional information structure guides the search for an antecedent within the sentence.
cmp-lg/9605023
A Simple Transformation for Offline-Parsable Grammars and its Termination Properties
cmp-lg cs.CL
We present, in easily reproducible terms, a simple transformation for offline-parsable grammars which results in a provably terminating parsing program directly top-down interpretable in Prolog. The transformation consists in two steps: (1) removal of empty-productions, followed by: (2) left-recursion elimination. It...
cmp-lg/9605024
Using Terminological Knowledge Representation Languages to Manage Linguistic Resources
cmp-lg cs.CL
I examine how terminological languages can be used to manage linguistic data during NL research and development. In particular, I consider the lexical semantics task of characterizing semantic verb classes and show how the language can be extended to flag inconsistencies in verb class definitions, identify the need f...
cmp-lg/9605025
A Conceptual Reasoning Approach to Textual Ellipsis
cmp-lg cs.CL
We present a hybrid text understanding methodology for the resolution of textual ellipsis. It integrates conceptual criteria (based on the well-formedness and conceptual strength of role chains in a terminological knowledge base) and functional constraints reflecting the utterances' information structure (based on th...
cmp-lg/9605026
Trading off Completeness for Efficiency --- The \textsc{ParseTalk} Performance Grammar Approach to Real-World Text Parsing
cmp-lg cs.CL
We argue for a performance-based design of natural language grammars and their associated parsers in order to meet the constraints posed by real-world natural language understanding. This approach incorporates declarative and procedural knowledge about language and language use within an object-oriented specification...
cmp-lg/9605027
Restricted Parallelism in Object-Oriented Lexical Parsing
cmp-lg cs.CL
We present an approach to parallel natural language parsing which is based on a concurrent, object-oriented model of computation. A depth-first, yet incomplete parsing algorithm for a dependency grammar is specified and several restrictions on the degree of its parallelization are discussed.
cmp-lg/9605028
Towards Understanding Spontaneous Speech: Word Accuracy vs. Concept Accuracy
cmp-lg cs.CL
In this paper we describe an approach to automatic evaluation of both the speech recognition and understanding capabilities of a spoken dialogue system for train time table information. We use word accuracy for recognition and concept accuracy for understanding performance judgement. Both measures are calculated by c...
cmp-lg/9605029
Learning Word Association Norms Using Tree Cut Pair Models
cmp-lg cs.CL
We consider the problem of learning co-occurrence information between two word categories, or more in general between two discrete random variables taking values in a hierarchically classified domain. In particular, we consider the problem of learning the `association norm' defined by A(x,y)=p(x, y)/(p(x)*p(y)), wher...
cmp-lg/9605030
Incremental Centering and Center Ambiguity
cmp-lg cs.CL
In this paper, we present a model of anaphor resolution within the framework of the centering model. The consideration of an incremental processing mode introduces the need to manage structural ambiguity at the center level. Hence, the centering framework is further refined to account for local and global parsing amb...
cmp-lg/9605031
Efficient Algorithms for Parsing the DOP Model? A Reply to Joshua Goodman
cmp-lg cs.CL
This note is a reply to Joshua Goodman's paper "Efficient Algorithms for Parsing the DOP Model" (Goodman, 1996; cmp-lg/9604008). In his paper, Goodman makes a number of claims about (my work on) the Data-Oriented Parsing model (Bod, 1992-1996). This note shows that some of these claims must be mistaken.
cmp-lg/9605032
Synchronous Models of Language
cmp-lg cs.CL
In synchronous rewriting, the productions of two rewriting systems are paired and applied synchronously in the derivation of a pair of strings. We present a new synchronous rewriting system and argue that it can handle certain phenomena that are not covered by existing synchronous systems. We also prove some interest...
cmp-lg/9605033
Notes on LR Parser Design
cmp-lg cs.CL
The design of an LR parser based on interleaving the atomic symbol processing of a context-free backbone grammar with the full constraints of the underlying unification grammar is described. The parser employs a set of reduced constraints derived from the unification grammar in the LR parsing step. Gap threading is s...
cmp-lg/9605034
Handling Sparse Data by Successive Abstraction
cmp-lg cs.CL
A general, practical method for handling sparse data that avoids held-out data and iterative reestimation is derived from first principles. It has been tested on a part-of-speech tagging task and outperformed (deleted) interpolation with context-independent weights, even when the latter used a globally optimal parame...
cmp-lg/9605035
Example-Based Optimization of Surface-Generation Tables
cmp-lg cs.CL
A method is given that "inverts" a logic grammar and displays it from the point of view of the logical form, rather than from that of the word string. LR-compiling techniques are used to allow a recursive-descent generation algorithm to perform "functor merging" much in the same way as an LR parser performs prefix me...
cmp-lg/9605036
Parsing Algorithms and Metrics
cmp-lg cs.CL
Many different metrics exist for evaluating parsing results, including Viterbi, Crossing Brackets Rate, Zero Crossing Brackets Rate, and several others. However, most parsing algorithms, including the Viterbi algorithm, attempt to optimize the same metric, namely the probability of getting the correct labelled tree. ...
cmp-lg/9605037
Combining Trigram-based and Feature-based Methods for Context-Sensitive Spelling Correction
cmp-lg cs.CL
This paper addresses the problem of correcting spelling errors that result in valid, though unintended words (such as ``peace'' and ``piece'', or ``quiet'' and ``quite'') and also the problem of correcting particular word usage errors (such as ``amount'' and ``number'', or ``among'' and ``between''). Such corrections...
cmp-lg/9605038
Efficient Normal-Form Parsing for Combinatory Categorial Grammar
cmp-lg cs.CL
Under categorial grammars that have powerful rules like composition, a simple n-word sentence can have exponentially many parses. Generating all parses is inefficient and obscures whatever true semantic ambiguities are in the input. This paper addresses the problem for a fairly general form of Combinatory Categorial ...
cmp-lg/9606001
A Bayesian hybrid method for context-sensitive spelling correction
cmp-lg cs.CL
Two classes of methods have been shown to be useful for resolving lexical ambiguity. The first relies on the presence of particular words within some distance of the ambiguous target word; the second uses the pattern of words and part-of-speech tags around the target word. These methods have complementary coverage: t...
cmp-lg/9606002
Clustered Language Models with Context-Equivalent States
cmp-lg cs.CL
In this paper, a hierarchical context definition is added to an existing clustering algorithm in order to increase its robustness. The resulting algorithm, which clusters contexts and events separately, is used to experiment with different ways of defining the context a language model takes into account. The contexts...
cmp-lg/9606003
Morphological Cues for Lexical Semantics
cmp-lg cs.CL
Most natural language processing tasks require lexical semantic information. Automated acquisition of this information would thus increase the robustness and portability of NLP systems. This paper describes an acquisition method which makes use of fixed correspondences between derivational affixes and lexical semanti...
cmp-lg/9606004
Classification in Feature-based Default Inheritance Hierarchies
cmp-lg cs.CL
Increasingly, inheritance hierarchies are being used to reduce redundancy in natural language processing lexicons. Systems that utilize inheritance hierarchies need to be able to insert words under the optimal set of classes in these hierarchies. In this paper, we formalize this problem for feature-based default inhe...
cmp-lg/9606005
Part-of-Speech-Tagging using morphological information
cmp-lg cs.CL
This paper presents the results of an experiment to decide the question of authenticity of the supposedly spurious Rhesus - a attic tragedy sometimes credited to Euripides. The experiment involves use of statistics in order to test whether significant deviations in the distribution of word categories between Rhesus a...
cmp-lg/9606006
Coordination in Tree Adjoining Grammars: Formalization and Implementation
cmp-lg cs.CL
In this paper we show that an account for coordination can be constructed using the derivation structures in a lexicalized Tree Adjoining Grammar (LTAG). We present a notion of derivation in LTAGs that preserves the notion of fixed constituency in the LTAG lexicon while providing the flexibility needed for coordinati...
cmp-lg/9606007
Word Sense Disambiguation using Conceptual Density
cmp-lg cs.CL
This paper presents a method for the resolution of lexical ambiguity of nouns and its automatic evaluation over the Brown Corpus. The method relies on the use of the wide-coverage noun taxonomy of WordNet and the notion of conceptual distance among concepts, captured by a Conceptual Density formula developed for this...
cmp-lg/9606008
Coordination as a Direct Process
cmp-lg cs.CL
We propose a treatment of coordination based on the concepts of functor, argument and subcategorization. Its formalization comprises two parts which are conceptually independent. On one hand, we have extended the feature structure unification to disjunctive and set values in order to check the compatibility and the s...
cmp-lg/9606009
Modularizing Contexted Constraints
cmp-lg cs.CL
This paper describes a method for compiling a constraint-based grammar into a potentially more efficient form for processing. This method takes dependent disjunctions within a constraint formula and factors them into non-interacting groups whenever possible by determining their independence. When a group of dependent...
cmp-lg/9606010
An Information Structural Approach to Spoken Language Generation
cmp-lg cs.CL
This paper presents an architecture for the generation of spoken monologues with contextually appropriate intonation. A two-tiered information structure representation is used in the high-level content planning and sentence planning stages of generation to produce efficient, coherent speech that makes certain discour...
cmp-lg/9606011
An Empirical Study of Smoothing Techniques for Language Modeling
cmp-lg cs.CL
We present an extensive empirical comparison of several smoothing techniques in the domain of language modeling, including those described by Jelinek and Mercer (1980), Katz (1987), and Church and Gale (1991). We investigate for the first time how factors such as training data size, corpus (e.g., Brown versus Wall St...
cmp-lg/9606012
An Efficient Inductive Unsupervised Semantic Tagger
cmp-lg cs.CL
We report our development of a simple but fast and efficient inductive unsupervised semantic tagger for Chinese words. A POS hand-tagged corpus of 348,000 words is used. The corpus is being tagged in two steps. First, possible semantic tags are selected from a semantic dictionary(Tong Yi Ci Ci Lin), the POS and the c...
cmp-lg/9606013
Relating Turing's Formula and Zipf's Law
cmp-lg cs.CL
An asymptote is derived from Turing's local reestimation formula for population frequencies, and a local reestimation formula is derived from Zipf's law for the asymptotic behavior of population frequencies. The two are shown to be qualitatively different asymptotically, but nevertheless to be instances of a common c...
cmp-lg/9606014
Building Probabilistic Models for Natural Language
cmp-lg cs.CL
In this thesis, we investigate three problems involving the probabilistic modeling of language: smoothing n-gram models, statistical grammar induction, and bilingual sentence alignment. These three problems employ models at three different levels of language; they involve word-based, constituent-based, and sentence-b...
cmp-lg/9606015
Stabilizing the Richardson Algorithm by Controlling Chaos
cmp-lg chao-dyn comp-gas cond-mat cs.CL nlin.CD nlin.CG
By viewing the operations of the Richardson purification algorithm as a discrete time dynamical process, we propose a method to overcome the instability of the algorithm by controlling chaos. We present theoretical analysis and numerical results on the behavior and performance of the stabilized algorithm.
cmp-lg/9606016
A Probabilistic Disambiguation Method Based on Psycholinguistic Principles
cmp-lg cs.CL
We address the problem of structural disambiguation in syntactic parsing. In psycholinguistics, a number of principles of disambiguation have been proposed, notably the Lexical Preference Rule (LPR), the Right Association Principle (RAP), and the Attach Low and Parallel Principle (ALPP) (an extension of RAP). We argu...
cmp-lg/9606017
With raised eyebrows or the eyebrows raised ? A Neural Network Approach to Grammar Checking for Definiteness
cmp-lg cs.CL
In this paper, we use a feature model of the semantics of plural determiners to present an approach to grammar checking for definiteness. Using neural network techniques, a semantics -- morphological category mapping was learned. We then applied a textual encoding technique to the 125 occurences of the relevant categ...
cmp-lg/9606018
Compilation of Weighted Finite-State Transducers from Decision Trees
cmp-lg cs.CL
We report on a method for compiling decision trees into weighted finite-state transducers. The key assumptions are that the tree predictions specify how to rewrite symbols from an input string, and the decision at each tree node is stateable in terms of regular expressions on the input string. Each leaf node can then...
cmp-lg/9606019
Computational Complexity of Probabilistic Disambiguation by means of Tree-Grammars
cmp-lg cs.CL
This paper studies the computational complexity of disambiguation under probabilistic tree-grammars and context-free grammars. It presents a proof that the following problems are NP-hard: computing the Most Probable Parse (MPP) from a sentence or from a word-graph, and computing the Most Probable Sentence (MPS) from ...
cmp-lg/9606020
Computing Optimal Descriptions for Optimality Theory Grammars with Context-Free Position Structures
cmp-lg cs.CL
This paper describes an algorithm for computing optimal structural descriptions for Optimality Theory grammars with context-free position structures. This algorithm extends Tesar's dynamic programming approach [Tesar 1994][Tesar 1995] to computing optimal structural descriptions from regular to context-free structure...
cmp-lg/9606021
An Iterative Algorithm to Build Chinese Language Models
cmp-lg cs.CL
We present an iterative procedure to build a Chinese language model (LM). We segment Chinese text into words based on a word-based Chinese language model. However, the construction of a Chinese LM itself requires word boundaries. To get out of the chicken-and-egg problem, we propose an iterative procedure that altern...
cmp-lg/9606022
Two Questions about Data-Oriented Parsing
cmp-lg cs.CL
In this paper I present ongoing work on the data-oriented parsing (DOP) model. In previous work, DOP was tested on a cleaned-up set of analyzed part-of-speech strings from the Penn Treebank, achieving excellent test results. This left, however, two important questions unanswered: (1) how does DOP perform if tested on...
cmp-lg/9606023
A Robust System for Natural Spoken Dialogue
cmp-lg cs.CL
This paper describes a system that leads us to believe in the feasibility of constructing natural spoken dialogue systems in task-oriented domains. It specifically addresses the issue of robust interpretation of speech in the presence of recognition errors. Robustness is achieved by a combination of statistical error...
cmp-lg/9606024
A Data-Oriented Approach to Semantic Interpretation
cmp-lg cs.CL
In Data-Oriented Parsing (DOP), an annotated language corpus is used as a stochastic grammar. The most probable analysis of a new input sentence is constructed by combining sub-analyses from the corpus in the most probable way. This approach has been succesfully used for syntactic analysis, using corpora with syntact...
cmp-lg/9606025
Two Sources of Control over the Generation of Software Instructions
cmp-lg cs.CL
This paper presents an analysis conducted on a corpus of software instructions in French in order to establish whether task structure elements (the procedural representation of the users' tasks) are alone sufficient to control the grammatical resources of a text generator. We show that the construct of genre provides...
cmp-lg/9606026
An Efficient Compiler for Weighted Rewrite Rules
cmp-lg cs.CL
Context-dependent rewrite rules are used in many areas of natural language and speech processing. Work in computational phonology has demonstrated that, given certain conditions, such rewrite rules can be represented as finite-state transducers (FSTs). We describe a new algorithm for compiling rewrite rules into FSTs...
cmp-lg/9606027
Linguistic Structure as Composition and Perturbation
cmp-lg cs.CL
This paper discusses the problem of learning language from unprocessed text and speech signals, concentrating on the problem of learning a lexicon. In particular, it argues for a representation of language in which linguistic parameters like words are built by perturbing a composition of existing parameters. The powe...
cmp-lg/9606028
Maximizing Top-down Constraints for Unification-based Systems
cmp-lg cs.CL
A left-corner parsing algorithm with top-down filtering has been reported to show very efficient performance for unification-based systems. However, due to the nontermination of parsing with left-recursive grammars, top-down constraints must be weakened. In this paper, a general method of maximizing top-down constrai...
cmp-lg/9606029
Directed Replacement
cmp-lg cs.CL
This paper introduces to the finite-state calculus a family of directed replace operators. In contrast to the simple replace expression, UPPER -> LOWER, defined in Karttunen (ACL-95), the new directed version, UPPER @-> LOWER, yields an unambiguous transducer if the lower language consists of a single string. It tran...
cmp-lg/9606030
Minimizing Manual Annotation Cost In Supervised Training From Corpora
cmp-lg cs.CL
Corpus-based methods for natural language processing often use supervised training, requiring expensive manual annotation of training corpora. This paper investigates methods for reducing annotation cost by {\it sample selection}. In this approach, during training the learning program examines many unlabeled examples...
cmp-lg/9606031
Research on Architectures for Integrated Speech/Language Systems in Verbmobil
cmp-lg cs.CL
The German joint research project Verbmobil (VM) aims at the development of a speech to speech translation system. This paper reports on research done in our group which belongs to Verbmobil's subproject on system architectures (TP15). Our specific research areas are the construction of parsers for spontaneous speech...
cmp-lg/9606032
Integrating Multiple Knowledge Sources to Disambiguate Word Sense: An Exemplar-Based Approach
cmp-lg cs.CL
In this paper, we present a new approach for word sense disambiguation (WSD) using an exemplar-based learning algorithm. This approach integrates a diverse set of knowledge sources to disambiguate word sense, including part of speech of neighboring words, morphological form, the unordered set of surrounding words, lo...
cmp-lg/9607001
GramCheck: A Grammar and Style Checker
cmp-lg cs.CL
This paper presents a grammar and style checker demonstrator for Spanish and Greek native writers developed within the project GramCheck. Besides a brief grammar error typology for Spanish, a linguistically motivated approach to detection and diagnosis is presented, based on the generalized use of PROLOG extensions t...