Weak dual residuations applied to tropical linear equations

An extension to an algorithm of R.A. Cuninghame-Green and K. Zimmermann for solving equations with residuated functions is presented. This extension relies on the concept of weak residuation and in the so-called “strong property”. It is shown that a contextualization of this method to tropical linear equations, which will be denoted as Primal Method (in contrast with the Dual Method, another algorithm described in literature), generates a non-decreasing sequence which converges to the smallest solution in a special semimodule. It is also shown the connections of this method with previously published works

On Max-Plus Linear Dynamical System Theory: The Regulation Problem

A class of timed discrete event systems can be modeled by using Timed-Event Graphs, a class of timed Petri nets that can have its firing dynamic described by using an algebra called “Max-plus algebra”. For this kind of systems it may be desirable to enforce some timing constraints in steady state. In this paper, this problem is called a “max-plus regulation problem”. In this context we show a necessary condition for solving these regulation problems and in addition that this condition is sufficient for a large class of problems. The obtained controller is a simple linear static state feedback and can be computed using efficient pseudo-polynomial algorithms. Simulation results will illustrate the applicability of the proposed methodology

On max-plus linear dynamical system theory: the observation problem

In this paper, we are interested in the general problem of estimating a linear function of the states for a given Max-Plus linear dynamical system. More precisely, using only the current and past inputs/outputs of the system, we want to construct a sequence that converges in a finite number of steps to the value given by a linear function of the states, for all initial conditions of the system. We provide necessary and sufficient conditions to solve this general problem. We also define and study a Max-Plus version of the well-known Luenberger observer, which is a subclass of the general problem that we are interested in, and we also provide necessary and sufficient conditions to solve this particular problem of observer synthesis. Finally, we show that there are important connections between results in the Max-Plus domain and associated results in the standard linear systems theory

Estado Da Arte Da Literatura Científica Sobre Hancornia Speciosa: Tendências E Lacunas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The economic and scientific interest in Hancornia speciosa (mangabeira) has been growing in recent years, mainly due to the marketing of fruit and extraction of natural compounds with high pharmacological potential. In this study, a scientometric survey about mangabeira was carried out in order to promote and direct future studies on the species. As a result, low scientific productivity associated with this species was found, with only 131 articles published in the last 69 years. In addition, this study identified some trends in bibliographic production on mangabeira, among them: the increasing number of articles over the years; scientific dissemination in nationwide journals; the main focus of this study is associated with agronomic studies; the experimental approach is more frequent and usually associated with populations of restricted geographical distribution; and the scientific production is mainly from education institutions. Furthermore, this study also allowed the identification of some gaps in knowledge about mangabeira, among them the difficulty in describing and characterizing botanical lines; lack of analysis of the genetic diversity of widely distributed populations; lack of management and conservation projects for the species; lack of description of cultivation, collection and preservation techniques of fruits; and lack of identification of natural compounds responsible for its pharmacological activity. It is expected that the data generated in this study will serve to direct future studies on H. speciosa. © 2016, Sociedade Brasileira de Fruticultura. All rights reserved.384CAPES, Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorCNPq, Conselho Nacional de Desenvolvimento Científico e TecnológicoFAPEG, Fundação de Amparo à Pesquisa do Estado de GoiásFINEP, Financiadora de Estudos e ProjetosCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

On the Steady State Control of Timed Event Graphs with Firing Date Constraints

Two algorithms for solving a specific class of steadystate control problems for Timed Event Graphs are presented. In the first, asymptotic convergence to the desired set is guaranteed. The second algorithm, which builds on from the recent developments in the spectral theory of min-max functions, guarantees Lyapunov stability since the distance between the actual state and the desired set never increases. Simulation results show the efficiency of the proposed approach in a problem of moderate complexity

An Observer for Tropical Linear Event-Invariant Dynamical Systems

This paper presents a sufficient condition to solve the observation problem in tropical linear event-invariant dynamical systems, where a linear functional of the states can be observed in a finite number of steps using only the information from inputs and outputs. Using the residuation theory, this solvability condition can be easily implemented in polynomial time. Moreover, the main results are applied to state feedback control using only the observed states based on the measurements of the original states in the system. Furthermore, the main results are implemented in the perturbation observation problem for tropical linear event-invariant dynamical systems, where the system matrices are perturbed in intervals.

Efeito de espécies vegetais em bordadura em cebola sobre a densidade populacional de tripes e sirfídeos predadores.

Analisou-se a relação entre o efeito do plantio de diferentes espécies vegetais, em bordadura, na cultura da cebola, Allium cepa L, na incidência de Thrips tabaci Lind. e sirfídeos predadores, Toxomerus spp. O experimento foi conduzido na Epagri, EE de Ituporanga, de agosto a dezembro de 1998. Os tratamentos foram cebola em monocultivo; cebola + trigo mourisco (Fagopyrum esculentum Moench); cebola + nabo forrageiro (Raphanus sativus L. var. oleiferus Metzg.); cebola + cenoura (Daucus carota L., cv. Nantes e cv. Brasília); cebola + milho (Zea mays L.); cebola + rúcula (Eruca sativa L.) + vegetação espontânea. O plantio de diferentes espécies vegetais em bordadura não provocou diferenças significativas na incidência de tripes e sirfídeos predadores. A produtividade comercial de bulbos de cebola foi similar em sistema de monocultivo e diversificado, sugerindo ser possível adotar tais sistemas sem perdas em rendimento

Gold nanoparticles as a part of a photothermal therapy system.

Introduction Photothermal therapy (PTT) is attracting increased attention for the treatment of superficial localized tumors, relying on the induction of local hyperthermia of tumor cells upon their irradiation with light beams1. PTT efficacy depends, however, on the heat generated and, on the depth reached by the light. Some strategies to improve PTT efficacy includes the use of the near infrared (NIR, 650 to 900 nm) radiation to enhance the penetration depth of the light, combined with gold nanoparticles (AuNPs) to enhance the photothermal effect2. Experimental Methods Core AuNPs were synthesized by a novel method using tetrachloroauric acid and a mixture of reducing agents, and subsequently coated with a combination of hyaluronic and oleic acids, for improving the NPs biocompatibility, biodegradability, and lifetime. This coating also promotes the binding of specific cell receptors of the tumor cells. The particles were physico-chemically characterized, and in vitro and in vivo tests were carried out in breast cancer models to assess their safety and efficacy, when applied alone or combined with NIR irradiation3. Results and Discussion AuNPs presented a predominant spherical morphology with sizes under 350 nm, polydispersity index lower than 0.4 and enhanced absorbance in the NIR. The particles showed no toxicity in vitro and promising efficacy in vivo when administering the NPs in situ and later irradiating them externally. Histopathological analysis of tumors treated with both AuNPs and laser irradiation showed the presence of necrosis in most of the tumors and no effect or practically absence in healthy surrounding cells, which are very encouraging outcomes. Conclusion The results are promising, however, there is still room for improving the system, namely by reducing even more the invasiveness of the treatment through the combined use of aerogels structures. Aerogel’s unique properties4 make them ideal candidates to minimize the exposure of healthy tissues to laser radiation, acting as light and thermal insulators, as well as to incorporate the nanoparticles into their skeletal structure and thus potentiating a topical application of the particles. For these reasons, some exploratory methods were carried to produce and design aerogels structures for PTT applications