Results 1 to 10 of about 170,686 (340)
Translations on a context free grammar [PDF]
Information and Control, 1969 Two schemes for the specification of translations on a context-free grammar are proposed. The first scheme, called a generalized syntax directed translation (GSDT), consists of a context free grammar with a set of semantic rules associated with each production of the grammar.
Alfred V. Aho, Jeffrey D. Ullman
semanticscholar +5 more sources
A stochastic context free grammar based framework for analysis of protein sequences [PDF]
BMC Bioinformatics, 2009 Background In the last decade, there have been many applications of formal language theory in bioinformatics such as RNA structure prediction and detection of patterns in DNA.
Nebel Jean-Christophe, Dyrka Witold
doaj +3 more sources
LPG–PCFG: An Improved Probabilistic Context- Free Grammar to Hit Low-Probability Passwords [PDF]
Sensors, 2022 With the development of the Internet, information security has attracted more attention. Identity authentication based on password authentication is the first line of defense; however, the password-generation model is widely used in offline password ...
Xiaozhou Guo +4 more
doaj +2 more sources
A synchronous context free grammar for time normalization. [PDF]
Proc Conf Empir Methods Nat Lang Process, 2013 We present an approach to time normalization (e.g. the day before yesterday⇒2013-04-12) based on a synchronous context free grammar. Synchronous rules map the source language to formally defined operators for manipulating times (FindEnclosed ...
Bethard S.
europepmc +2 more sources
On a property of probabilistic context-free grammars [PDF]
International Journal of Mathematics and Mathematical Sciences, 1983 It is proved that for a probabilistic context‐free language L(G), the population density of a character (terminal symbol) is equal to its relative density in the words of a sample S from L(G) whenever the production probabilities of the grammar G are estimated by the relative frequencies of the corresponding productions in the sample.
Ranjan Chaudhuri, A.N.V. Rao
openalex +7 more sources
Fast Context-Free Grammar Parsing Requires Fast Boolean Matrix Multiplication [PDF]
JACM, 2001 In 1975, Valiant showed that Boolean matrix multiplication can be used for parsing context-free grammars (CFGs), yielding the asympotically fastest (although not practical) CFG parsing algorithm known.
Lillian Lee
openalex +3 more sources
Analyzing ambiguity of context-free grammars [PDF]
BRICS Report Series, 2009 <p>It has been known since 1962 that the ambiguity problem for context-free grammars is undecidable. Ambiguity in context-free grammars is a recurring problem in language design and parser generation, as well as in applications where grammars are used as models of real-world physical structures.
Claus Brabrand +2 more
openalex +9 more sources
Non-context-free grammars generating context-free languages
Information and Control, 1974 If G is a grammar such that in each non-context-free rule of G, the right side contains a string of terminals longer than any terminal string appearing between two nonterminals in the left side, then the language generated by G is context free. Six previous results follow as corollaries of this theorem.
Brenda S. Baker
openalex +3 more sources
Cross-Domain Feature Enhancement-Based Password Guessing Method for Small Samples [PDF]
EntropyAs a crucial component of account protection system evaluation and intrusion detection, the advancement of password guessing technology encounters challenges due to its reliance on password data. In password guessing research, there is a conflict between
Cheng Liu +7 more
doaj +2 more sources
Implicit learning of recursive context-free grammars.
PLoS ONE, 2012 Context-free grammars are fundamental for the description of linguistic syntax. However, most artificial grammar learning experiments have explored learning of simpler finite-state grammars, while studies exploring context-free grammars have not assessed
Martin Rohrmeier +2 more
doaj +3 more sources