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In this paper we introduce a fuzzy version of symport/antiport membrane systems. Our fuzzy membrane systems handle possibly inexact copies of reactives and their rules are endowed with threshold functions that determine whether a rule can be applied or not to a given set of objects, depending of the degree of accuracy of these objects to the reactives specified in the rule. We prove that these fuzzy membrane systems generate exactly the recursively enumerable finite-valued fuzzy subsets of ℕ.

In this paper, a numerical method for the analysis of smart structures with uncertainties involved in the material parameters is presented. This method combines the finite element technique, concepts of fuzzy sets and optimization. For the optimization of fuzzy parameters, a sensitivity index is proposed. The sensitivity analysis based on the proposed sensitivity index can be effectively used to reduce the number of variables to be fuzzified and thus reducing the computational efforts considerably.

This work proposes an heuristic approach based on evolutionary computation, whose goal is to find a set of k-spanning trees with lowest costs in graphs that contain uncertainties in their parameters. In order to avoid the high complex ordinary resolution, this work presents a genetic approach to explore the space of solutions looking for satisfactory results, without the necessity of comparing all possible solutions.