614 research outputs found
On Hamiltonians with position-dependent mass from Kaluza-Klein compactifications
In a recent paper (J.R. Morris, Quant. Stud. Math. Found. 2 (2015) 359), an
inhomogeneous compactification of the extra dimension of a five-dimensional
Kaluza-Klein metric has been shown to generate a position-dependent mass (PDM)
in the corresponding four-dimensional system. As an application of this
dimensional reduction mechanism, a specific static dilatonic scalar field has
been connected with a PDM Lagrangian describing a well-known nonlinear PDM
oscillator. Here we present more instances of this construction that lead to
PDM systems with radial symmetry, and the properties of their corresponding
inhomogeneous extra dimensions are compared with the ones in the nonlinear
oscillator model. Moreover, it is also shown how the compactification
introduced in this type of models can alternatively be interpreted as a novel
mechanism for the dynamical generation of curvature.Comment: 11 pages, 6 figures. New figures. Updated to match the published
version in Physics Letters
Logic Negation with Spiking Neural P Systems
Nowadays, the success of neural networks as reasoning systems is doubtless.
Nonetheless, one of the drawbacks of such reasoning systems is that they work
as black-boxes and the acquired knowledge is not human readable. In this paper,
we present a new step in order to close the gap between connectionist and logic
based reasoning systems. We show that two of the most used inference rules for
obtaining negative information in rule based reasoning systems, the so-called
Closed World Assumption and Negation as Finite Failure can be characterized by
means of spiking neural P systems, a formal model of the third generation of
neural networks born in the framework of membrane computing.Comment: 25 pages, 1 figur
Other Buds in Membrane Computing
It is well-known the huge Mario’s contribution to the development
of Membrane Computing. Many researchers may relate his name
to the theory of complexity classes in P systems, the research of frontiers
of the tractability or the application of Membrane Computing to
model real-life situations as the Quorum Sensing System in Vibrio fischeri
or the Bearded Vulture ecosystem. Beyond these research areas, in
the last years Mario has presented many new research lines which can
be considered as buds in the robust Membrane Computing tree. Many of
them were the origin of new research branches, but some others are still
waiting to be developed. This paper revisits some of these buds
A P-Lingua Programming Environment for Membrane Computing
A new programming language for membrane computing, PLingua,
is developed in this paper. This language is not designed for
a speci c simulator software. On the contrary, its purpose is to o er
a general syntactic framework that could de ne a uni ed standard for
membrane computing, covering a broad variety of models. At the present
stage, P-Lingua can only handle P systems with active membranes, although
the authors intend to extend it to other models in the near future.
P-Lingua allows to write programs in a friendly way, as its syntax is
very close to standard scienti c notation, and parameterized expressions
can be used as shorthand for sets of rules. There is a built-in compiler
that parses these human-style programs and generates XML documents
that can be given as input to simulation tools, di erent plugins can be
designed to produce speci c adequate outputs for existing simulators.
Furthermore, we present in this paper an integrated development environment
that plays the role of interface where P-lingua programs can
be written and compiled. We also present a simulator for the class of
recognizer P systems with active membranes, and we illustrate it by following
the writing, compiling and simulating processes with a family of
P systems solving the SAT problem.Ministerio de Educación y Ciencia TIN2006-13425Junta de Andalucía TIC-58
Performing Arithmetic Operations with Spiking Neural P Systems
We consider spiking neural P systems as devices which can be used to perform some basic arithmetic operations, namely addition, subtraction, comparison and
multiplication by a fixed factor. The input to these systems are natural numbers expressed in binary form, encoded as appropriate sequences of spikes. A single system
accepts as inputs numbers of any size. The present work may be considered as a ¯rst
step towards the design of a CPU based on the working of spiking neural P systems.Ministerio de Educación y Ciencia TIN2006–13425Junta de Andalucía P08-TIC-0420
A Case Study in (Mem)Brane Computation: Generating Squares of Natural Numbers
The aim of this paper is to start an investigation and a comparison
of the expressiveness of the two most relevant formalisms inspired
by membranes interactions, namely, P systems and Brane Calculi. We
compare the two formalisms with respect to their ability to act as generator
devices. In particular, we show different ways of generating the set
L = {n2 | n ≥ 1} in P systems and in Brane Calculi.Ministerio de Educación y Ciencia TIN2005-09345-C03-01Junta de Andalucía TIC-58
A Case Study in (Mem)Brane Computation: Generating {n2 | n 1}
The aim of this paper is to start an investigation and a comparison of the
expressiveness of the two most relevant formalisms inspired by membranes interactions,
namely, P systems and Brane Calculi. We compare the two formalisms w.r.t. their ability
to act as language generators. In particular, we show different ways of generating the set
L = {n2 | n 1} in P systems and in Brane Calculi.Ministerio de Educación y Ciencia TIC2002-04220-C03-0
A Characterization of PSPACE with Antimatter and Membrane Creation
The use of negative information provides a new tool for exploring the limits
of P systems as computational devices. In this paper we prove that the combination of
antimatter and annihilation rules (based on the annihilation of physical particles and
antiparticles) and membrane creation (based on autopoiesis) provides a P system model
able to solve PSPACE-complete problems. Namely, we provide a uniform family of
P system in such P system model which solves the satis ability problem for quanti ed
Boolean formulas (QSAT). In the second part of the paper, we prove that all the decision
problems which can be solved with this P system model belong to the complexity class
PSPACE, so this P system model characterises PSPACE.Ministerio de Economía y Competitividad TIN2012-3743
Some Notes on (Mem)Brane Computation
Membrane Computing and Brane Calculi are two recent computational
paradigms in the framework of Natural Computing. They are
based on the study of the structure and functioning of living cells as living
organisms able to process and generate information. In this paper we give
a short introduction to both areas and point out some open research lines.Ministerio de Educación y Ciencia TIN2005-09345-C04-01Junta de Andalucía TIC-58
An Application of Genetic Algorithms to Membrane Computing
The process of designing a P system in order to perform a task is a hard
job. The researcher has often only an approximate idea of the design, but finding the
exact description of the rules is a heavy hand-made work. In this paper we introduce
PSystemEvolver, an evolutionary algorithm based on generative encoding, that could help
to design a P system to perform a specific task. We illustrate the use of PSystemEvolver
with a simple mathematical problem: the computation of squared numbers.Ministerio de Ciencia e Innovación TIN2008-04487-EMinisterio de Ciencia e Innovación TIN-2009-13192Junta de Andalucía P08-TIC-0420
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