Recently, Augmented Regular Expressions (AREs) have been proposed as a formalism to describe and recognize a non-trivial class of context-sensitive languages (CSLs), that covers planar shapes with symmetries 1, 2]. AREs augment the expressive power of Regular Expressions (REs) by including a set of constraints, that involve the number of instances in a string of the operands of the star operati...

In this paper, we present a generic Optical Character Recognition system for Arabic script languages called Nabocr. Nabocr uses OCR approaches specific for Arabic script recognition. Performing recognition on Arabic script text is relatively more difficult than Latin text due to the nature of Arabic script, which is cursive and context sensitive. Moreover, Arabic script has different writing st...

The DUST module has been used within BLAST for many years to mask low-complexity sequences. In this paper, we present a new implementation of the DUST module that uses the same function to assign a complexity score to a sequence, but uses a different rule by which high-scoring sequences are masked. The new rule masks every nucleotide masked by the old rule and occasionally masks more. The new m...

— By considering représentations of graphs of relations on the set of natural numbers by bounded languages it is possible to develop a study of relations which are computable in a certain sensé by context-sensitive grammars. There are obtained closure proprieties for the class of these relations, which allow to prove the context-sensitiveness of certain languages. Résumé. — En représentant les ...

Investigations of classes of grammars that are nontransformational and at the same time highly constrained are of interest both linguistically and mathematically. Context-free grammars (CFG) obviously form such a class. CFGs are not adequate (both weakly and strongly) to characterize some aspects of language structure. Thus how much more power beyond CFG is necessary to describe these phenomena...

A recent hypothesis in empirical brain research on language is that the fundamental difference between animal and human communication systems is captured by the distinction between finite-state and more complex phrase-structure grammars, such as context-free and context-sensitive grammars. However, the relevance of this distinction for the study of language as a neurobiological system has been ...

Recently much concern has been given to the problem of the generative adequacy of different types of grammars, [ l ] , [2], [3], [4], [5], [6] and [7]. There are certain types of dependencies in languages which constitute a crucial test for grammars in this respect; languages with certain types of dependencies cannot be generated by certain grammars, while they can be generated by others. For i...

Pseudoknots are a frequent RNA structure that assumes essential roles for varied biocatalyst cell’s functions. One of the most challenging fields in bioinformatics is the prediction of this secondary structure based on the base-pair sequence that dictates it. Previously, a model adapted from computational linguistics – Stochastic Context Free Grammars (SCFG) – has been used to predict RNA secon...

Linear Context Free Rewriting Systems (LCFRS, [Wei88]) are a general class of trans-context-free grammar systems; it is the largest well-known class of mildly context sensitive grammar; languages recognized by LCFRS strictly include those generated by the HG, TAG, LIG, CCG family. (Parallel) Multiple Context-Free Grammar (PMCFG, [KNSK92]) is a straightforward extension of LCFRS. Literal Movemen...

The knowledge representation tradition in computational lexicon design represents words as static encapsulations of purely lexical knowledge. We suggest that this view poses certain limitations on the ability of the lexicon to generate nuance-laden and context-sensitive meanings, because word boundaries are obstructive, and the impact of non-lexical knowledge on meaning is unaccounted for. Hopi...