P systems with communication based on concentration

We consider a variant of P systems where the communication of objects is controlled by the "concentration" of these objects: after each evolution step, the objects are redistributed among the regions of the system in such a way that each region contains the same number of copies of each object (plus/minus one, when the number of objects is not divisible by the number of regions). We show that P systems of this form, with only one flip-flop catalyst but without using other control ingredients, can generate the Parikh images of all matrix languages. When an unbounded number of catalysts is available, a characterization of recursively enumerable sets of vectors of natural numbers is obtained (by systems with only one membrane)

Membrane Computing and Economics: A General View

Three are the points we briefly discuss here: using membrane computing tools for efficient computing/optimization, the possibilities of using “general" membrane computing (P systems using multisets of symbol objects processed by biochemical-like evolution rules) as a framework for modeling economic processes, and the numerical P systems, a class of computing devices explicitly defined with a motivation related to economics. The discussion is rather informal, only pointing out research directions and providing bibliographical information

ENERGY PLANTS ALTERNATIVE TO FUTURE BIOFUEL PRODUCTION

Replacing fossil fuels with alternative renewable energy sources is a very current issue worldwide. The development of energy plant (lingo-cellulosic) crops represents the promising solution, for the future production of biofuels in order to produce renewable energy and replace fossil fuels. For the implementation of energy crops were elaborated a series of technologies and technical equipment that respond to the requirements of these crops. The paper addresses these technologies, technical equipment and technologies for valorizing energy crops

Structuring grammar systems by priorities and hierarchies

A grammar system is a finite set of grammars that cooperate to generate a language. We consider two generalizations of grammar systems: (l) adding a priority relation between single grammar components, and (2) considering hierarchical components which by themselves are grammar systems. The generative power of these generalized grammar systems is investigated, and compared with the generative power of ordinary grammar systems and of some well-known types of grammars with regulated rewriting (such as matrix grammars). We prove that for many cooperating strategies the use of priority relation increases the generative capacity, however this is not the case for the maximal mode of derivation (an important case, because it gives a characterization of the ETOL languages). We also demonstrate that in many cases the use of hierarchical components does not increase the generative power

Test generation from P systems using model checking

This paper presents some testing approaches based on model checking and using different testing criteria. First, test sets are built from different Kripke structure representations. Second, various rule coverage criteria for transitional, non-deterministic, cell-like P systems, are considered in order to generate adequate test sets. Rule based coverage criteria (simple rule coverage, context-dependent rule coverage and variants) are defined and, for each criterion, a set of LTL (Linear Temporal Logic) formulas is provided. A codification of a P system as a Kripke structure and the sets of LTL properties are used in test generation: for each criterion, test cases are obtained from the counterexamples of the associated LTL formulas, which are automatically generated from the Kripke structure codification of the P system. The method is illustrated with an implementation using a specific model checker, NuSMV. (C) 2010 Elsevier Inc. All rights reserved