Showing papers on "Chomsky hierarchy published in 2017"

Derivation Languages of Splicing P Systems

Abstract: Labelled splicing P systems are distributed parallel computing models, where sets of strings that evolve by splicing rules are labelled. In this work, we consider labelled splicing systems with the following modifications: (i) The strings in the membranes are present in arbitrary number of copies; (ii) the rules in the regions are finite in number. Results on the language family generated by the labelled splicing system in comparison with the language families of the Chomsky hierarchy, including recursively enumerable languages, are obtained, by involving only either one or two membranes in the P systems considered.

A New Linguistic Engine for NooJ: Parsing Context-Sensitive Grammars with Finite-State Machines

Abstract: NooJ is a linguistic development environment that allows linguists to construct large linguistic resources of the four types in the Chomsky hierarchy. NooJ uses a bottom-up, “cascade” approach to sequentially apply these linguistic resources: each parsing operation accesses a Text Annotation Structure, and enriches it by adding or removing linguistic annotations to it. We discuss the drawbacks of this approach, and we present a new approach that requires that all NooJ linguistic resources be represented by a single type of finite-state machine. In order to do that, we must solve theoretical problems such as “how to handle Context-Sensitive Grammars with finite-state machines”, as well as some engineering problems such as “how to compose sets of large dictionaries and grammars into a single finite-state machine”. Our first experiments show that although that composing large finite-state machines is extremely costly theoretically, the fact that linguistic resources in a typical NooJ cascade depend on each other heavily keeps the size of all intermediary machines manageable. Once the final resulting finite-state machine has been compiled and loaded in memory (e.g. on a webserver) it can be used to parse large texts in linear time.

The Computational Power of Neural Networks and Representations of Numbers in Non-Integer Bases

Abstract: We briefly survey the basic concepts and results concerning the computational power of neural net-orks which basically depends on the information content of eight parameters. In particular, recurrent neural networks with integer, rational, and arbitrary real weights are classi ed within the Chomsky and finer complexity hierarchies. Then we re ne the analysis between integer and rational weights by investigating an intermediate model of integer-weight neural networks with an extra analog rational-weight neuron (1ANN). We show a representation theorem which characterizes the classification problems solvable by 1ANNs, by using so-called cut languages. Our analysis reveals an interesting link to an active research field on non-standard positional numeral systems with non-integer bases. Within this framework, we introduce a new concept of quasi-periodic numbers which is used to classify the computational power of 1ANNs within the Chomsky hierarchy.

Variants of weighted sticker systems with different weighting spaces

Abstract: Sticker systems have been introduced as one of the DNA computing models by using the recombination behavior of DNA molecules in 1998. Abstractly, the systems use the Watson-Crick complementary principle of DNA molecules to perform the computation in generating new strings. By associating some weights to the axioms and dominoes of sticker system, a new version of restricted sticker system namely weighted sticker system has been introduced. In this paper, we study the generative power of weighted sticker systems by considering the languages generated by weighted sticker system with different weighting spaces and cut-points. The relations of the languages generated by weighted sticker systems in the Chomsky hierarchy are also investigated.

Label Languages of 8-directional Array P System

Abstract: An 8-directional array P system is one where the rewriting of an array can happen in any 8-directions. The array rules of such a system are labelled thus resulting in a labelled 8-directional array P system. The labelling is not unique and the label language is obtained by recording the strings over the labels used in any terminating derivation of the P system. The system is shown to generate interesting pictures. The label language is compared with Chomsky hierarchy.