We investigate the complexity of a variety of normal-form transformations for extended context-free grammars, where by extended we mean that the set of right-hand sides for each nonterminal in such a grammar is a regular set. The study is motivated by the implementation project GraMa which will provide a C++ toolkit for the symbolic manipulation of context-free objects just as Grail does for re...

A hierarchical three-stage syntactic recognition algorithm using context-free grammars is described for automatic identification of skeletal maturity from X-rays of hand and wrist. The primitives considered are dot, straight line and arcs of three different curvatures (including both senses) in order to describe and interpret the structural development of epiphysis and metaphysis with growth of...

We investigate the complexity of a variety of normal-form transformations for extended context-free grammars, where by extended we mean that the set of right-hand sides for each nonterminal in such a grammar is a regular set. The study is motivated by the implementation project GraMa which will provide a C++ toolkit for the symbolic manipulation of context-free objects just as Grail does for re...

We investigate a new type of finite copying parallel rewriting system, i.e., grammars with linked nonterminals, which extend the generative capacity of context-free grammars. They can be thought of as having sentential forms where some instances of a nonterminal may be linked. The context-free-like productions replace a nonterminal together with its connected instances. New links are only estab...

Today the syntax of many languages is defined by using context-free grammars. These syntax definitions suffer from a major drawback: grammars do not allow the definition of abstract, reusable concept definitions. Especially in families of related languages, where multiple languages often share the same concepts, this limitation leads to unnecessary reproduction of concept definitions and a miss...

We propose an algebra of languages and transformations as a means for ex-tending languages syntactically. The algebra provides a layer of high-level ab-stractions built on top of languages (captured by context-free grammars) andtransformations (captured by constructive catamorphisms).The algebra is self-contained in that any term of the algebra specifying atransformation...

We present a new approach to motion rearrangement that preserves the syntactic structures of an input motion automatically by learning a context-free grammar from the motion data. For grammatical analysis, we reduce an input motion into a string of terminal symbols by segmenting the motion into a series of subsequences, and then associating a group of similar subsequences with the same symbol. ...

Context-sensitive analysis provides information which is potentially more accurate than that provided by context-free analysis. Such information can then be applied in order to validate/debug the program and/or to specialize the program obtaining important improvements. Unfortunately, context-sensitive analysis of modular programs poses important theoretical and practical problems. One solution...

Retrieval dynamics in context-dependent recall were explored via manipulations of external and internal context in two experiments. Participants were tested in either the same or different context as the material was learned in and correct recalls, errors, and recall latency measures were examined. In both experiments changes in context resulted in fewer correct items being recalled than when c...