3 research outputs found
Uniform solutions to SAT and Subset Sum by spiking neural P systems
We continue the investigations concerning the possibility of using spiking neural
P systems as a framework for solving computationally hard problems, addressing two
problems which were already recently considered in this respect: Subset Sum and SAT: For
both of them we provide uniform constructions of standard spiking neural P systems (i.e.,
not using extended rules or parallel use of rules) which solve these problems in a constant
number of steps, working in a non-deterministic way. This improves known results of this
type where the construction was non-uniform, and/or was using various ingredients added
to the initial definition of spiking neural P systems (the SN P systems as defined initially are
called here ‘‘standard’’). However, in the Subset Sum case, a price to pay for this
improvement is that the solution is obtained either in a time which depends on the value of
the numbers involved in the problem, or by using a system whose size depends on the same
values, or again by using complicated regular expressions. A uniform solution to 3-SAT is
also provided, that works in constant time.Ministerio de Educación y Ciencia TIN2006-13425Junta de Andalucía TIC-581Ministerio de Educación y Ciencia HI 2005-019
Membrane computing: traces, neural inspired models, controls
Membrane Computing:Traces, Neural Inspired Models, ControlsAutor: Armand-Mihai IonescuDirectores: Dr. Victor Mitrana (URV)Dr. Takashi Yokomori (Universidad Waseda, Japón)Resumen Castellano:El presente trabajo está dedicado a una área muy activa del cálculo natural (que intenta descubrir la odalidad en la cual la naturaleza calcula, especialmente al nivel biológico), es decir el cálculo con membranas, y más preciso, a los modelos de membranas inspirados de la funcionalidad biológica de la neurona.La disertación contribuye al área de cálculo con membranas en tres direcciones principales. Primero, introducimos una nueva manera de definir el resultado de una computación siguiendo los rastros de un objeto especificado dentro de una estructura celular o de una estructura neuronal. A continuación, nos acercamos al ámbito de la biología del cerebro, con el objetivo de obtener varias maneras de controlar la computación por medio de procesos que inhiben/de-inhiben. Tercero, introducimos e investigamos en detallo - aunque en una fase preliminar porque muchos aspectos tienen que ser clarificados - una clase de sistemas inspirados de la manera en la cual las neuronas cooperan por medio de spikes, pulsos eléctricos de formas idénticas.English summary:The present work is dedicated to a very active branch of natural computing (which tries to discover the way nature computes, especially at a biological level), namely membrane computing, more precisely, to those models of membrane systems mainly inspired from the functioning of the neural cell.The present dissertation contributes to membrane computing in three main directions. First, we introduce a new way of defining the result of a computation by means of following the traces of a specified object within a cell structure or a neural structure. Then, we get closer to the biology of the brain, considering various ways to control the computation by means of inhibiting/de-inhibiting processes. Third, we introduce and investigate in a great - though preliminary, as many issues remain to be clarified - detail a class of P systems inspired from the way neurons cooperate by means of spikes, electrical pulses of identical shapes