1,101 research outputs found
DCU 250 Arabic dependency bank: an LFG gold standard resource for the Arabic Penn treebank
This paper describes the construction of a dependency bank gold standard for Arabic, DCU 250 Arabic Dependency Bank (DCU 250), based on the Arabic Penn Treebank Corpus (ATB) (Bies and Maamouri, 2003; Maamouri and Bies, 2004) within the theoretical framework of Lexical Functional Grammar (LFG). For parsing and automatically extracting grammatical and lexical resources from treebanks, it is necessary to evaluate against established gold standard resources. Gold standards for various languages have been developed, but to our knowledge, such a resource has not yet been constructed for Arabic. The construction of the DCU 250 marks the first step
towards the creation of an automatic LFG f-structure annotation algorithm for the ATB,
and for the extraction of Arabic grammatical and lexical resources
Efficient Groundness Analysis in Prolog
Boolean functions can be used to express the groundness of, and trace
grounding dependencies between, program variables in (constraint) logic
programs. In this paper, a variety of issues pertaining to the efficient Prolog
implementation of groundness analysis are investigated, focusing on the domain
of definite Boolean functions, Def. The systematic design of the representation
of an abstract domain is discussed in relation to its impact on the algorithmic
complexity of the domain operations; the most frequently called operations
should be the most lightweight. This methodology is applied to Def, resulting
in a new representation, together with new algorithms for its domain operations
utilising previously unexploited properties of Def -- for instance,
quadratic-time entailment checking. The iteration strategy driving the analysis
is also discussed and a simple, but very effective, optimisation of induced
magic is described. The analysis can be implemented straightforwardly in Prolog
and the use of a non-ground representation results in an efficient, scalable
tool which does not require widening to be invoked, even on the largest
benchmarks. An extensive experimental evaluation is givenComment: 31 pages To appear in Theory and Practice of Logic Programmin
Compiling and Using Finite-State Syntactic Rules
Proceeding volume: 1A language-independent framework for syntactic finlte-state parsing is discussed. The article presents a framework, a formalism, a compiler and a parser for grammars written in this forrealism. As a substantial example, fragments from a nontrivial finite-state grammar of English are discussed. The linguistic framework of the present approach is based on a surface syntactic tagging scheme by F. Karlsson. This representation is slightly less powerful than phrase structure tree notation, letUng some ambiguous constructions be described more concisely. The finite-state rule compiler implements what was briefly sketched by Koskenniemi (1990). It is based on the calculus of finite-state machines. The compiler transforms rules into rule-automata. The run-time parser exploits one of certain alternative strategies in performing the effective intersection of the rule automata and the sentence automaton. Fragments of a fairly comprehensive finite-state granmmr of English are presented here, including samples from non-finite constructions as a demonstration of the capacity of the present formalism, which goes far beyond plain disamblguation or part of speech tagging. The grammar itself is directly related to a parser and tagging system for English created as a part of project SIMPR I using Karlsson's CG (Constraint Grammar) formalism.Peer reviewe
A calibration method for non-positive definite covariance matrix in multivariate data analysis
Covariance matrices that fail to be positive definite arise often in covariance estimation. Approaches addressing this problem exist, but are not well supported theoretically. In this paper, we propose a unified statistical and numerical matrix calibration, finding the optimal positive definite surrogate in the sense of Frobenius norm. The proposed algorithm can be directly applied to any estimated covariance matrix. Numerical results show that the calibrated matrix is typically closer to the true covariance, while making only limited changes to the original covariance structure
Spain, Economic Crisis, and the New Enclosure of the Reproductive Commons
In the past f ew years numerous authors have examined how the current economic crisis in Spain has
dif f erential impacts on women and men.1 While this is important to show, this articleâs goal is to make the
leap f rom a mere description of the gendered effects of the crisis, to an analysis of some of the very
gendered processes that shape it at its core. In other words, the intent is to understand how both the crisis
itself and the ways the state manages it are structurally shaped by gender
- âŚ