Computación celular con membranas: un estudio de modelos de cómputo bioinspirados

Los resultados presentados en la memoria de esta tesis doctoral se enmarcan en la denominada computación celular con membranas una nueva rama de investigación dentro de la computación natural creada por Gh. Paun en 1998, de ahí que habitualmente reciba el nombre de sistemas P. Este nuevo modelo de cómputo distribuido está inspirado en la estructura y funcionamiento de la célula. El objetivo de esta tesis ha sido analizar el poder y la eficiencia computacional de estos sistemas de computación celular. En concreto, se han analizado dos tipos de sistemas P: por un lado los sistemas P de neuronas de impulsos, y por otro los sistemas P con proteínas en las membranas. Para el primer tipo, los resultados obtenidos demuestran que es posible que estos sistemas mantengan su universalidad aunque muchas de sus características se limiten o incluso se eliminen. Para el segundo tipo, se analiza la eficiencia computacional y se demuestra que son capaces de resolver problemas de la clase de complejidad ESPACIO-P (PSPACE) en tiempo polinómico. Análisis del poder computacional: Los sistemas P de neuronas de impulsos (en adelante SN P, acrónimo procedente del inglés «Spiking Neural P Systems») son sistemas inspirados en el funcionamiento neuronal y en la forma en la que los impulsos se propagan por las redes sinápticas. Los SN P bio-inpirados poseen un numeroso abanico de características que ha cen que dichos sistemas sean universales y por tanto equivalentes, en poder computacional, a una máquina de Turing. Estos sistemas son potentes a nivel computacional, pero tal y como se definen incorporan numerosas características, quizás demasiadas. En (Ibarra et al. 2007) se demostró que en estos sistemas sus funcionalidades podrían ser limitadas sin comprometer su universalidad. Los resultados presentados en esta memoria son continuistas con la línea de trabajo de (Ibarra et al. 2007) y aportan nuevas formas normales. Esto es, nuevas variantes simplificadas de los sistemas SN P con un conjunto mínimo de funcionalidades pero que mantienen su poder computacional universal. Análisis de la eficiencia computacional: En esta tesis se ha estudiado la eficiencia computacional de los denominados sistemas P con proteínas en las membranas. Se muestra que este modelo de cómputo es equivalente a las máquinas de acceso aleatorio paralelas (PRAM) o a las máquinas de Turing alterantes ya que se demuestra que un sistema P con proteínas, es capaz de resolver un problema ESPACIOP-Completo como el QSAT(problema de satisfacibilidad de fórmulas lógicas cuantificado) en tiempo polinómico. Esta variante de sistemas P con proteínas es muy eficiente gracias al poder de las proteínas a la hora de catalizar los procesos de comunicación intercelulares. ABSTRACT The results presented at this thesis belong to membrane computing a new research branch inside of Natural computing. This new branch was created by Gh. Paun on 1998, hence usually receives the name of P Systems. This new distributed computing model is inspired on structure and functioning of cell. The aim of this thesis is to analyze the efficiency and computational power of these computational cellular systems. Specifically there have been analyzed two different classes of P systems. On the one hand it has been analyzed the Neural Spiking P Systems, and on the other hand it has been analyzed the P systems with proteins on membranes. For the first class it is shown that it is possible to reduce or restrict the characteristics of these kind of systems without loss of computational power. For the second class it is analyzed the computational efficiency solving on polynomial time PSACE problems. Computational Power Analysis: The spiking neural P systems (SN P in short) are systems inspired by the way of neural cells operate sending spikes through the synaptic networks. The bio-inspired SN Ps possess a large range of features that make these systems to be universal and therefore equivalent in computational power to a Turing machine. Such systems are computationally powerful, but by definition they incorporate a lot of features, perhaps too much. In (Ibarra et al. in 2007) it was shown that their functionality may be limited without compromising its universality. The results presented herein continue the (Ibarra et al. 2007) line of work providing new formal forms. That is, new SN P simplified variants with a minimum set of functionalities but keeping the universal computational power. Computational Efficiency Analisys: In this thesis we study the computational efficiency of P systems with proteins on membranes. We show that this computational model is equivalent to parallel random access machine (PRAM) or alternating Turing machine because, we show P Systems with proteins can solve a PSPACE-Complete problem as QSAT (Quantified Propositional Satisfiability Problem) on polynomial time. This variant of P Systems with proteins is very efficient thanks to computational power of proteins to catalyze inter-cellular communication processes.

Communication-efficient and crash-quiescent Omega with unknown membership

The failure detector class Omega (Ω) provides an eventual leader election functionality, i.e., eventually all correct processes permanently trust the same correct process. An algorithm is communication-efficient if the number of links that carry messages forever is bounded by n, being n the number of processes in the system. It has been defined that an algorithm is crash-quiescent if it eventually stops sending messages to crashed processes. In this regard, it has been recently shown the impossibility of implementing Ω crash quiescently without a majority of correct processes. We say that the membership is unknown if each process pi only knows its own identity and the number of processes in the system (that is, i and n), but pi does not know the identity of the rest of processes of the system. There is a type of link (denoted by ADD link) in which a bounded (but unknown) number of consecutive messages can be delayed or lost. In this work we present the first implementation (to our knowledge) of Ω in partially synchronous systems with ADD links and with unknown membership. Furthermore, it is the first implementation of Ω that combines two very interesting properties: communication-efficiency and crash-quiescence when the majority of processes are correct. Finally, we also obtain with the same algorithm a failure detector () such that every correct process eventually and permanently outputs the set of all correct processes.

Novel system for bite-force sensing and monitoring based on magnetic eear field communication

Intraoral devices for bite-force sensing have several applications in odontology and maxillofacial surgery, as bite-force measurements provide additional information to help understand the characteristics of bruxism disorders and can also be of help for the evaluation of post-surgical evolution and for comparison of alternative treatments. A new system for measuring human bite forces is proposed in this work. This system has future applications for the monitoring of bruxism events and as a complement for its conventional diagnosis. Bruxism is a pathology consisting of grinding or tight clenching of the upper and lower teeth, which leads to several problems such as lesions to the teeth, headaches, orofacial pain and important disorders of the temporomandibular joint. The prototype uses a magnetic field communication scheme similar to low-frequency radio frequency identification (RFID) technology (NFC). The reader generates a low-frequency magnetic field that is used as the information carrier and powers the sensor. The system is notable because it uses an intra-mouth passive sensor and an external interrogator, which remotely records and processes information regarding a patient?s dental activity. This permits a quantitative assessment of bite-force, without requiring intra-mouth batteries, and can provide supplementary information to polysomnographic recordings, current most adequate early diagnostic method, so as to initiate corrective actions before irreversible dental wear appears. In addition to describing the system?s operational principles and the manufacture of personalized prototypes, this report will also demonstrate the feasibility of the system and results from the first in vitro and in vivo trials.

An Architecture forRepresenting Biological Processes based on Networks of Bio-inspired Processors

n this paper we propose the use of Networks of Bio-inspired Processors (NBP) to model some biological phenomena within a computational framework. In particular, we propose the use of an extension of NBP named Network Evolutionary Processors Transducers to simulate chemical transformations of substances. Within a biological process, chemical transformations of substances are basic operations in the change of the state of the cell. Previously, it has been proved that NBP are computationally complete, that is, they are able to solve NP complete problems in linear time, using massively parallel computations. In addition, we propose a multilayer architecture that will allow us to design models of biological processes related to cellular communication as well as their implications in the metabolic pathways. Subsequently, these models can be applied not only to biological-cellular instances but, possibly, also to configure instances of interactive processes in many other fields like population interactions, ecological trophic networks, in dustrial ecosystems, etc.

Improving manufacturing performance by standardization of interprocess communication

A number of environmental forces such as increasing value chain network complexity, decreasing product life-cycle cost, and time-to-market requirements or increasing product complexity act upon manufacturing organizations, enhancing the acute need for organizational routines that foster efficient and effective communication between processes. Such organizational routines erode quickly in the absence of common standards for knowledge sharing, that is why successful manufacturing systems benefit from interprocess standardization. The purpose of this paper is to offer a standardization model of interprocess communication that increases manufacturing operational performance (MOP). First, we propose a novel holistic model that makes standardized interprocess communication possible in manufacturing organizations. Second, we propose a model for quantifying the implications of standardizing interprocess communication upon MOP. Finally, as a matter of application, we show the results of its successful implementation in one Japanese manufacturing organization.