OALib Journal期刊

ISSN: 2333-9721



匹配条件: “Taufer” ,找到相关结果约15条。
A note on the empirical process of strongly dependent stable random variables
Emanuele Taufer
Statistics , 2014, DOI: 10.1016/j.spl.2015.07.032
Abstract: This paper analyzes the limit properties of the empirical process of $\alpha$-stable random variables with long range dependence. The $\alpha$-stable random variables are constructed by non-linear transformations of bivariate sequences of strongly dependent gaussian processes. The approach followed allows an analysis of the empirical process by means of expansions in terms of bivariate Hermite polynomials for the full range $0<\alpha<2$. A weak uniform reduction principle is provided and it is shown that the limiting process is gaussian. The results of the paper different substantailly from those available for empirical processes obtained by stable moving averages with long memory. An application to goodness-of-fit testing is discussed.
Uncertainties in Plant Optimum Definition
Milan Jav rek, Ivan Taufer
Acta Mechanica Slovaca , 2009, DOI: 10.2478/v10147-010-0038-9
Abstract: The article presents a method of simulated determination of the optimum regime in a reactor in which a competitive consecutive reaction A → B → C takes place. The algorithm of optimization method of Kiefer-Johnson is described (method with Fibonacci numbers using), and results of experimental determination of the optimum are given. Also described are the methods of determination of limit values of confidence intervals, and the confidence intervals - uncertainty of "measured" values are evaluated from experimental data. Good accordance between the experimental results and theoretical presumptions is stated.
Piecewise-linear artificial neural networks for PID controller tuning
Petr Dole?el,Ivan Taufer
Acta Montanistica Slovaca , 2012,
Abstract: A new algorithm of PID controller tuning is presented in this paper. It is well known that there have been introduced manytechniques for PID controller tuning, both theoretical and experimental ones. However, this algorithm is suitable especially forhighly nonlinear processes. It uses a model of the controlled process in the shape of piecewise-linear neural network which islinearized continuously and resulting linearized model is used for PID controller online tuning. While at the beginning of the paperthe algorithm is described in theory, at the end there are mentioned some practical applications
Adaptive Control of Non-linear System Using Neural Network
Ivan Taufer, Old ich Drábek
Acta Mechanica Slovaca , 2010, DOI: 10.2478/v10147-011-0007-y
Abstract: The paper deals with one of possible methods for control of non-linear dynamical system, namely with the adaptive neural PS controller (ANPSC). Its principle is in on-line refinement of the model system and then in the adaptive adjustment of the controller parameters. The model of the plant is realized with a two-layer feedforward neural network. The control part of the ANPSC has the structure of the classical PS controller, and it is also created in the form of the neural network (simple perceptron). The simulation calculations were performed in MATLAB.
Identification of nonlinear systems based on mathematical physical analysis and least square method
Taufer Ivan,Drábek Old?ich
Acta Montanistica Slovaca , 2003,
Abstract: The paper deals with the identification of nonlinear systems described by the nonlinear difference equations of the certain type. These equations are known in literature dealing with the systems modelling by means of neural network as the models of the second type. In some cases, when these models are nonlinear also in parameters and we want to use the least square method for parameter estimation, it is necessary to transform the models into linear forms. Our attention has chiefly been paid to the practical utilization of the proposed algorithm and to this verification on simulated example.
The Artifical Neural Network as means for modeling Nonlinear Systems
Taufer Ivan,Drábek Old?ich
Acta Montanistica Slovaca , 1998,
Abstract: The paper deals with nonlinear system identification based on neural network. The topic of this publication is simulation of training and testing a neural network. A contribution is assigned to technologists which are good at the clasical identification problems but their knowledges about identification based on neural network are only on the stage of theoretical bases.
Atividade fásica do sono rem em recém-nascidos e lactentes e sua rela??o com episódios de apnéia
Nunes, Magda Lahorgue;Costa, Jaderson Costa da;Taufer, Letícia;
Arquivos de Neuro-Psiquiatria , 1997, DOI: 10.1590/S0004-282X1997000200008
Abstract: when the apnea hypothesis turned to be an explanation for sudden infant death syndrome (sids) many authors tried to find if near-miss or apparent life-threatening events (alte) could be markers of sids. it was suggested that phasic rem activity is associated with increased respiratory neuron activity and prevents prolonged apnea in near-miss sids. in a previous retrospective study with newborns we did not confirm these results, nevertheless we had several babies with serious neurological disturbances. the aim of this study was to verify the relationship of phasic activity (rapid eyes movement and sucking bursts) with both apneic and non-apneic epochs during rem sleep. we studied 86 children refered for evaluation because they presented an alte during sleep or apneas. the subjects were divided in three groups by age (newborns, n=31; 1 -6 months, n= 48; and >6< 12 months, n=7). they were all submitted to a clinical and neurological evaluation in order to detect possible etiological factors to the apneic episode. the po.lysomnograms (ps) consisted of eeg, submental emg, electro-oculogram and cardiorespiratory monitoring. the records were made between 11 am and 15 pm for 2 or 3 hours. the electrodes were disposed in the 10-20 system. during one five-minutes epoch of rem sleep we verified the incidence of phasic activity (rapid eyes movement or sucking bursts) time locked to apneic episodes and compared with a similar duration non-apneic epoch. to evaluate the relationship of phasic activity with apneic and non-apneic epochs we compared the incidence of rapid eyes movements and sucking bursts in each group. our results showed that phasic activity of rem sleep (sucking bursts) seems to be more frequent in newborns in non-apneic epochs (p < 0.05). between 1-6 months the number of rapid eyes movements were more frequent in non-apneic epochs (p=0.00l). in conclusion our findings suggest that phasic activity of rem sleep seems to be more evident in nonapneic epochs during the
In-Situ Data Analysis of Protein Folding Trajectories
Travis Johnston,Boyu Zhang,Adam Liwo,Silvia Crivelli,Michela Taufer
Computer Science , 2015,
Abstract: The transition from petascale to exascale computers is characterized by substantial changes in the computer architectures and technologies. The research community relying on computational simulations is being forced to revisit the algorithms for data generation and analysis due to various concerns, such as higher degrees of concurrency, deeper memory hierarchies, substantial I/O and communication constraints. Simulations today typically save all data to analyze later. Simulations at the exascale will require us to analyze data as it is generated and save only what is really needed for analysis, which must be performed predominately in-situ, i.e., executed sufficiently fast locally, limiting memory and disk usage, and avoiding the need to move large data across nodes. In this paper, we present a distributed method that enables in-situ data analysis for large protein folding trajectory datasets. Traditional trajectory analysis methods currently follow a centralized approach that moves the trajectory datasets to a centralized node and processes the data only after simulations have been completed. Our method, on the other hand, captures conformational information in-situ using local data only while reducing the storage space needed for the part of the trajectory under consideration. This method processes the input trajectory data in one pass, breaks from the centralized approach of traditional analysis, avoids the movement of trajectory data, and still builds the global knowledge on the formation of individual $\alpha$-helices or $\beta$-strands as trajectory frames are generated.
Asymptotic Properties of the Partition Function and Applications in Tail Index Inference of Heavy-Tailed Data
Danijel Grahovac,Mofei Jia,Nikolai N. Leonenko,Emanuele Taufer
Statistics , 2013,
Abstract: The so-called partition function is a sample moment statistic based on blocks of data and it is often used in the context of multifractal processes. It will be shown that its behaviour is strongly influenced by the tail of the distribution underlying the data either in i.i.d. and weakly dependent cases. These results will be exploited to develop graphical and estimation methods for the tail index of a distribution. The performance of the tools proposed is analyzed and compared with other methods by means of simulations and examples.
Efeito da temperatura na matura??o ovariana e longevidade de Anastrepha fraterculus (Wied.) (Diptera: Tephritidae)
Taufer, Maristela;Nascimento, Jurema C. do;Cruz, Ivana B. M. da;Oliveira, Alice K. de;
Anais da Sociedade Entomológica do Brasil , 2000, DOI: 10.1590/S0301-80592000000400003
Abstract: anastrepha fraterculus (wied.) shows a populational fluctuation related to the year season in southern brazil. adults cannot be colected by means of conventional methods of capture in the winter. even with the use of special traps, a very low number of adults is caught. two hypothesis are pointed out to explain the increase of the population at spring: a) adults migrate from neighbouring areas with temperature more favourable during winter, and b) some individuals that can survive the critical period develop a differential metabolic regulation. in this paper the second hypothesis was tested by studying the effect of four temperatures (9, 13, 20 and 25oc) on ovarian maturation and longevity of the females. only at 25 and 20oc ovarian maturation has occurred. the life expectancy was larger in the intermediate temperatures (20 and 13oc) than in the extreme temperatures (25 and 9oc). the relation between ovarian maturation and longevity was observed at 25 and 20oc, although at 25oc the ovarian maturation was faster, but the life expectancy was lower. therefore, the hypothesis of developmental regulation cannot be discarded as a populational mechanism in a. fraterculus for its populational increase in the months subsequent to the winter.

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