On differentiation functions, structure functions, and related languages of context-free grammars

Studying impressive parameters on the performance of Persian probabilistic context free grammar parser

In linguistics, a tree bank is a parsed text corpus that annotates syntactic or semantic sentence structure. The exploitation of tree bank data has been important ever since the first large-scale tree bank, The Penn Treebank, was published. However, although originating in computational linguistics, the value of tree bank is becoming more widely appreciated in linguistics research as a whole. F...

A Comparative Study on Formal Grammars for Pseudoknots

Much attention has been paid to RNA secondary structure predicition based on context-free grammar (cfg) since cfg can represent stem-loop structure by its derivation tree. Especially, techniques based on CKY (Cocke-Kasami-Younger) algorithm have been widely investigated [1]. Pseudoknots play an important role in RNA functions such as ribosomal frameshifting and splicing. A database (PseudoBase)...

Ambiguity functions of context-free grammars and languages

Attributed Context-Free Hypergraph Grammars

The concept of context-free hypergraph grammars (cfhg grammars) has been studied extensively over the past decade. In this paper we introduce attributed context-free hypergraph grammars (acfhg grammars) as an extension of cfhg grammars. An acfhg grammar consists of an underlying context-free hypergraph grammar G 0 and an attribution which associates attributes with the nonterminal symbols of G ...

Learning Semantic Functions of Attribute Grammars

Attribute grammars can be considered as an extension of context-free grammars, where the attributes are associated with grammar symbols, and the semantic rules deene the values of the attributes. This formalism is widely applied for the speciication and implementation of the compilation-oriented languages. The paper presents a method for learning semantic functions of attribute grammars which i...