Time After Time: Notes on Delays In Spiking Neural P Systems

Spiking Neural P systems, SNP systems for short, are biologically inspired computing devices based on how neurons perform computations. SNP systems use only one type of symbol, the spike, in the computations. Information is encoded in the time differences of spikes or the multiplicity of spikes produced at certain times. SNP systems with delays (associated with rules) and those without delays are two of several Turing complete SNP system variants in literature. In this work we investigate how restricted forms of SNP systems with delays can be simulated by SNP systems without delays. We show the simulations for the following spike routing constructs: sequential, iteration, join, and split.Comment: 11 pages, 9 figures, 4 lemmas, 1 theorem, preprint of Workshop on Computation: Theory and Practice 2012 at DLSU, Manila together with UP Diliman, DLSU, Tokyo Institute of Technology, and Osaka universit

Computing with cells: membrane systems - some complexity issues.

Membrane computing is a branch of natural computing which abstracts computing models from the structure and the functioning of the living cell. The main ingredients of membrane systems, called P systems, are (i) the membrane structure, which consists of a hierarchical arrangements of membranes which delimit compartments where (ii) multisets of symbols, called objects, evolve according to (iii) sets of rules which are localised and associated with compartments. By using the rules in a nondeterministic/deterministic maximally parallel manner, transitions between the system configurations can be obtained. A sequence of transitions is a computation of how the system is evolving. Various ways of controlling the transfer of objects from one membrane to another and applying the rules, as well as possibilities to dissolve, divide or create membranes have been studied. Membrane systems have a great potential for implementing massively concurrent systems in an efficient way that would allow us to solve currently intractable problems once future biotechnology gives way to a practical bio-realization. In this paper we survey some interesting and fundamental complexity issues such as universality vs. nonuniversality, determinism vs. nondeterminism, membrane and alphabet size hierarchies, characterizations of context-sensitive languages and other language classes and various notions of parallelism

Bounded Languages Meet Cellular Automata with Sparse Communication

Cellular automata are one-dimensional arrays of interconnected interacting finite automata. We investigate one of the weakest classes, the real-time one-way cellular automata, and impose an additional restriction on their inter-cell communication by bounding the number of allowed uses of the links between cells. Moreover, we consider the devices as acceptors for bounded languages in order to explore the borderline at which non-trivial decidability problems of cellular automata classes become decidable. It is shown that even devices with drastically reduced communication, that is, each two neighboring cells may communicate only constantly often, accept bounded languages that are not semilinear. If the number of communications is at least logarithmic in the length of the input, several problems are undecidable. The same result is obtained for classes where the total number of communications during a computation is linearly bounded

Presenting in Virtual Worlds: An Architecture for a 3D Anthropomorphic Presenter

Multiparty-interaction technology is changing entertainment, education, and training. Deployed examples of such technology include embodied agents and robots that act as a museum guide, a news presenter, a teacher, a receptionist, or someone trying to sell you insurance, homes, or tickets. In all these cases, the embodied agent needs to explain and describe. This article describes the design of a 3D virtual presenter that uses different output channels (including speech and animation of posture, pointing, and involuntary movements) to present and explain. The behavior is scripted and synchronized with a 2D display containing associated text and regions (slides, drawings, and paintings) at which the presenter can point. This article is part of a special issue on interactive entertainment

On Languages Accepted by P/T Systems Composed of joins

Recently, some studies linked the computational power of abstract computing systems based on multiset rewriting to models of Petri nets and the computation power of these nets to their topology. In turn, the computational power of these abstract computing devices can be understood by just looking at their topology, that is, information flow. Here we continue this line of research introducing J languages and proving that they can be accepted by place/transition systems whose underlying net is composed only of joins. Moreover, we investigate how J languages relate to other families of formal languages. In particular, we show that every J language can be accepted by a log n space-bounded non-deterministic Turing machine with a one-way read-only input. We also show that every J language has a semilinear Parikh map and that J languages and context-free languages (CFLs) are incomparable

gtfB and spaP virulence genes in Streptococcus mutans strains and their relationship with the DMFT index

Universidad de Talca, Chile; Vásquez Ibarra, Sonia; Lobos Gilabert, Olga; Padilla Espinoza, CarlosObjetivo: El propósito de este estudio fue determinar la presencia de genes de virulencia en cepas de Streptococcus mutans (S. mutans) aisladas desde saliva de individuos de diferentes edades y asociarlas con el índice COPD y ceod según corresponda. Material y método: A partir de un total de 120 individuos de ambos sexos, se conformaron 4 grupos de 30 personas, que se separaron de acuerdo con los siguientes rangos etarios: 3-5, 6-9, 12-15 y mayores de 18 años. A cada individuo se le determinó el índice COPD y ceod según correspondiera y se realizó recuento salival de S. mutans. La detección de los genes de virulencia: gtfB y spaP se realizó por reacción en cadena de la polimerasa convencional. Resultados: Se estableció una asociación positiva entre el recuento bacteriano e índice COPD y ceod. El 100% de las cepas aisladas evidenciaron la presencia del gen gtfB y el 63,6% presentaron el gen spaP. No hubo evidencia estadísticamente significativa que relacionará un alto recuento bacteriano e índice COPD y ceod con la mayor presencia de genes que codifican factores de virulencia en cepas de S. mutans. Resumen: Aim: The aim of this study was to determine the presence of gtfB and spaP virulence genes in Streptococcus mutans strains isolated from saliva taken from individuals of different ages. Material and method: A total of 120 individuals of both sexes were studied. They were assigned to one of 4 groups, with 30 individuals in each one, according to age; 3-5, 6-9, 12-15, and older than 18 years old. DMFT (decayed, missing, and filled teeth) and DMFT indexes were determined in each participant, depending on his/her age. S. mutans microbial counts were performed. The gtfB and spaP virulence genes were detected using conventional PCR. Results: A positive association was found between microbial count and DMFT and DMFT indexes. All the isolated strains demonstrated the presence of gtfB, and 63.6% of the strains had spaP genes. No association was found between high bacterial counts or DMFT and DMFT indexes with the presence of genes that code for virulence factors in S. mutans strains

Supersymmetric free-damped oscillators: Adaptive observer estimation of the Riccati parameter

A supersymmetric class of free damped oscillators with three parameters has been obtained in 1998 by Rosu and Reyes through the factorization of the Newton equation. The supplementary parameter is the integration constant of the general Riccati solution. The estimation of the latter parameter is performed here by employing the recent adaptive observer scheme of Besancon et al., but applied in a nonstandard form in which a time-varying quantity containing the unknown Riccati parameter is estimated first. Results of computer simulations are presented to illustrate the good feasibility of this approach for a case in which the estimation is not easily accomplished by other meansComment: 8 pages, 6 figure

The Brightest Cluster Galaxy in Abell 85: The Largest Core Known so far

We have found that the brightest cluster galaxy (BCG) in Abell~85, Holm 15A, displays the largest core so far known. Its cusp radius, $r_{\gamma} = 4.57 \pm 0.06$ kpc ($4.26^{\prime\prime}\pm 0.06^{\prime\prime}$), is more than 18 times larger than the mean for BCGs, and $\geq1$ kpc larger than A2261-BCG, hitherto the largest-cored BCG (Postman, Lauer, Donahue, et al. 2012) Holm 15A hosts the luminous amorphous radio source 0039-095B and has the optical signature of a LINER. Scaling laws indicate that this core could host a supermassive black hole (SMBH) of mass $M_{\bullet}\thicksim (10^{9}-10^{11})\,M_{\odot}$. We suggest that cores this large represent a relatively short phase in the evolution of BCGs, whereas the masses of their associated SBMH might be set by initial conditions.Comment: 14 pages, 3 figure, 2 tables, accepted for publication in ApJ Letters on October 6th, 2014, replacement of previous manuscript submitted on May 30th, 2014 to astro-p

Asynchronous spiking neural P systems

We consider here spiking neural P systems with a non-synchronized (i.e., asynchronous) use of rules: in any step, a neuron can apply or not apply its rules which are enabled by the number of spikes it contains (further spikes can come, thus changing the rules enabled in the next step). Because the time between two firings of the output neuron is now irrelevant, the result of a computation is the number of spikes sent out by the system, not the distance between certain spikes leaving the system. The additional non-determinism introduced in the functioning of the system by the non-synchronization is proved not to decrease the computing power in the case of using extended rules (several spikes can be produced by a rule). That is, we obtain again the equivalence with Turing machines (interpreted as generators of sets of (vectors of) numbers). However, this problem remains open for the case of standard spiking neural P systems, whose rules can only produce one spike. On the other hand we prove that asynchronous systems, with extended rules, and where each neuron is either bounded or unbounded, are not computationally complete. For these systems, the configuration reachability, membership (in terms of generated vectors), emptiness, infiniteness, and disjointness problems are shown to be decidable. However, containment and equivalence are undecidable. © 2009 Elsevier B.V. All rights reserved

La onomástica de nombres erróneos en la construcción de andinidad fallida y débil andeancia: el imperativo de microrefugios bioculturales en los Andes

We seek to (re)construct a geocritical narrative for the essence of place, by (re)writing mountain specificities that imprint cultural traits on tropical and temperate Andean landscapes, creating a unique identity trilemma for the people of highland South America. We use onomastics as a study of mistaken individuality, with a poststructuralism approach to define ‘the Andean’ within humanistic geoecology; thus, we incorporate notions related to common phenotypic traits of ‘Andeanity’, together with cryptic, emergent properties of ‘Andeaness’ and mystic conditions of spirituality of ‘Andeanitude’, to produce a new trifecta of ecoregional building, with a challenging epistemology for ‘Andean’ as a biocultural heritage landscape informed from traditional knowledge, dialectically appropriated from the old and the young, the foreign and the native, and the original and the composed. Hence, the imagined, heterogeneous, and dynamic identity of Andean people is characterized as dynamic and evolving flow of the mountainscape. We argue that it is still adapting to frameworks of global environment change; hence, it is subjected to withering if not for certain biocultural microrefugia that keep Andean landscape memory alive. With a review of the hermeneutics of Andes, because of orthographic variants (c.f.: graphiosis) that incorporated Kichwa-based, Kañary-based or Mapudungun-based words in the hegemonic lexicon of colonial expansionism of Castilian terms, we argue for the inclusion of vernacular descriptors instead of Roman Sanctorum or Patriotic ephemerides utilized to name geographical features in Andean South America. A plea to restore vernacular descriptors with the original peoples’ language uses, toponymy and onomatopoeia, brings political recognition and invigorates original communities’ pride of their ancestral heritage to reinforce their wellbeing in biodiversity microrefugia. Switching from imperial, imposed names of colonialist geographies to vernacular words or other non-hegemonic locatives of (de) colonial scholarship will help find a better “sense of place” in the Andes and will increase the likelihood of survival and (re)generation of ancestral socio-ecological production Andean mountainscapes.Buscamos (re)construir una narrativa geocrítica para la esencia del paisaje al (re)escribir las especificidades de montaña que impriman atributos culturales en los paisajes andinos tropicales y templados, creando un trilema de identidad único para la gente de las tierras altas de América del Sur. Usamos la onomástica como un estudio de la individualidad errada con un enfoque post-estructuralista para definir “lo andino” dentro de la geoecología humanística; por lo tanto, incorporamos nociones relacionadas con los atributos fenotípicos de Andeanidad, junto con las propiedades crípticas emergentes de Andeancia y las condiciones místicas de espiritualidad de Andeanitud, para producir una nueva trifecta de construcción ecoregional, con una epistemología desafiante para el paisaje patrimonial biocultural basado en el conocimiento tradicional, apropiado dialécticamente de lo viejo a lo nuevo, de lo foráneo a lo nativo y de lo original a lo copiado. Por lo tanto, la dinámica identidad heterogénea imaginada de la gente andina está caracterizada por un flujo dinámico y evolutivo del paisaje montano. Argumentamos que la nomenclatura aún se adapta a marcos de cambio ambiental global; así, está aún sujeta a deterioro a no ser que ciertos microrefugios bioculturales puedan mantener la memoria del paisaje andino vivo. Con una revisión de la hermenéutica de Andes, debido a las variantes (c.f. grafiosis) que incorporaron palabras basadas en Kichwa, Kañary o Mapudungun en el léxico hegemónico del expansionismo colonial de los términos castellanos, apelamos a la inclusión de los descriptores vernáculos en vez del santoral romano y la efemérides patriótica utilizada para nombrar los atributos geográficos en la Sudamérica andina. Pedimos restaurar los descriptores vernáculos con el lenguaje usado por los pueblos originarios, su toponimia y onomatopeya, para atraer el reconocimiento político y para vigorizar el orgullo del patrimonio ancestral de las comunidades de montaña para refuerzo de su bienestar en los microrefugios bioculturales. Al cambiar los nombres impuestos por la geografía imperial colonial a las palabras vernáculas u otros locativos no hegemónicos de escolaridad decolonial, se ayudará a obtener un mejor ‘sentido del lugar’ en los Andes e incrementará la posibilidad de (super)vivencia y (re)generación de los paisajes productivos socioecológicos ancestrales andinos