Although large-scale grammars are prerequisite for parsing a great variety of sentences, it is difficult to build such grammars by hand. Yet, it is possible to build a context-free grammar (CFG) by deriving it from a syntactically annotated corpus. Many such corpora have been built recently to obtain statistical information concerning corpus-based NLP technologies. For English, it is well known...

Valiant showed that Boolean matrix multiplication (BMM) can be used for CFG parsing. We prove a dual result: CFG parsers running in time O([Gl[w[ 3-e) on a grammar G and a string w can be used to multiply m x m Boolean matrices in time O(m3-e/3). In the process we also provide a formal definition of parsing motivated by an informal notion due to Lang. Our result establishes one of the first lim...

An empirical comparison of CFG filtering techniques for LTAG and HPSG is presented. We demonstrate that an approximation of HPSG produces a more effective CFG filter than that of LTAG. We also investigate the reason for that difference.

Parsing is one of the important processes for natural language processing and, in general, a large-scale CFG is used to parse a wide variety of sentences. For many languages, a CFG is derived from a large-scale syntactically annotated corpus, and many parsing algorithms using CFGs have been proposed. However, we could not apply them to Japanese since a Japanese syntactically annotated corpus ha...

In command and control (C&C) speech interaction, users interact by speaking commands or asking questions typically specified in a context-free grammar (CFG). Unfortunately, users often produce out-ofgrammar (OOG) commands, which can result in misunderstanding or nonunderstanding. We explore a simple approach to handling OOG commands that involves generating a backoff grammar from any CFG using ...

In its recogniser form, Earley’s algorithm for testing whether a string can be derived from a grammar is worst case cubic on general context free grammars (CFG). Earley gave an outline of a method for turning his recognisers into parsers, but it turns out that this method is incorrect. Tomita’s GLR parser returns a shared packed parse forest (SPPF) representation of all derivations of a given s...

Inadequate feeding and care may contribute to high rates of stunting and underweight among children in rural families in India. This cluster-randomized trial tested the hypothesis that teaching caregivers appropriate complementary feeding and strategies for how to feed and play responsively through home-visits would increase children's dietary intake, growth and development compared with home-v...

Metamorphic malware propagation has persuaded the security society to consider about new approaches to confront this generation of malware with novel solutions. Control Flow Graph, CFG, has been successful in detection of simple malwares. By now, it needs to improve the CFG based detection methods to detect metamorphic malwares efficiently. Our Approach has improved the simple CFG with benefici...

Recently, the performance of HPSG parsing has been improved so that the parsers can be applied to real-world texts. CFG filtering is one of the techniques which contributed to this progress. It improved parsing speed by filtering impossible parse trees by using the CFG compiled from a given HPSGbased grammar. However, there is a limit in the speed-up. This is because the compiled CFG grows into...

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)...