167 research outputs found

    Compact representation for electroweak lepton sector

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    A new representation of electroweak lepton sector is proposed. It consists of two Weyl spinors per one lepton family. It is shown that proposed representation is fully equivalent to the conventional left-handed iso-doublet. New type of plane wave solutions can be found under certain additional assumptions.Comment: This arXiv submission is next revision after DOI publication. Some text was moved into the appendix, both title and abstract changed, however all equations, results, and 99% of text are the same as in DOI publicatio

    Nonlinear mean-field dynamo and prediction of solar activity

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    We apply a nonlinear mean-field dynamo model which includes a budget equation for the dynamics of Wolf numbers to predict solar activity. This dynamo model takes into account the algebraic and dynamic nonlinearities of the alpha effect, where the equation for the dynamic nonlinearity is derived from the conservation law for the magnetic helicity. The budget equation for the evolution of the Wolf number is based on a formation mechanism of sunspots related to the negative effective magnetic pressure instability. This instability redistributes the magnetic flux produced by the mean-field dynamo. To predict solar activity on the time scale of one month we use a method based on a combination of the numerical solution of the nonlinear mean-field dynamo equations and the artificial neural network. A comparison of the results of the prediction of the solar activity with the observed Wolf numbers demonstrates a good agreement between the forecast and observations.Comment: 15 pages, 6 figures, jpp.cls, final versio

    About specialities of numerical estimation of smoothing parameter of probability density functions of random sequences in Parzen-Rosenblatt approximation

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    The methods of nonparametric statistics are very useful in data analysis. One of the most popular methods is called Parzen-Rosenblatt approximation. This method turns out to be effective, for example, in a problem of estimation of longevity of pipelines or in the analysis of the statistical characteristics of traffic flows. This paper discusses the recommendations for application of a method, which was performed by Parzen and Rosenblatt, in a problem of recovering a probability density function from a sample of random data with a bounded scattering region. It was shown that there are some difficulties during calculation of information functional. This paper gives an explanation of causes which lead to a nonmonotonicity of an information functional and which are based on a finite precision of computer calculations. It was proved a choice of initial value of smoothing parameter for different kernel types and was proposed an algorithm for finding a maximal value of information functional. © Published under licence by IOP Publishing Ltd

    Eliminating fuzzy duplicates in crowdsourced lexical resources

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    Collaboratively created lexical resources is a trending approach to creating high quality thesauri in a short time span at a remarkably low price. The key idea is to invite non-expert participants to express and share their knowledge with the aim of constructing a resource. However, this approach tends to be noisy and error-prone, thus making data cleansing a highly topical task to perform. In this paper, we study different techniques for synset deduplication including machine- and crowd-based ones. Eventually, we put forward an approach that can solve the deduplication problem fully automatically, with the quality comparable to the expert-based approach

    The dynamics of Wolf numbers based on nonlinear dynamo with magnetic helicity: comparisons with observations

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    We investigate the dynamics of solar activity using a nonlinear one-dimensional dynamo model and a phenomenological equation for the evolution of Wolf numbers. This system of equations is solved numerically. We take into account the algebraic and dynamic nonlinearities of the alpha effect. The dynamic nonlinearity is related to the evolution of a small-scale magnetic helicity, and it leads to a complicated behavior of solar activity. The evolution equation for the Wolf number is based on a mechanism of formation of magnetic spots as a result of the negative effective magnetic pressure instability (NEMPI). This phenomenon was predicted 25 years ago and has been investigated intensively in recent years through direct numerical simulations and mean-field simulations. The evolution equation for the Wolf number includes the production and decay of sunspots. Comparison between the results of numerical simulations and observational data of Wolf numbers shows a 70 % correlation over all intervals of observation (about 270 years). We determine the dependence of the maximum value of the Wolf number versus the period of the cycle and the asymmetry of the solar cycles versus the amplitude of the cycle. These dependencies are in good agreement with observations.Comment: 9 pages, 13 figures, final revised paper for MNRA

    The study of methods for analysis burning torch infrared images

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    The paper describes the results of the study of methods for analysis burning torch infrared images obtained by an infrared camera in the band of electromagnetic wavelengths of 1.5-5.1 μm. It was shown that the known infrared image analysis methods cannot provide the quantitative parameters extraction that could describe combustion process. In addition, it was figured out that the known methods are time-consuming and cannot run in real time. As a result, nowadays the combustion control system that uses optical control of torch parameters in infrared band cannot be designed. In our study we analyzed the pixels quantity distribution density in the range of [520,560] relative Celsius degrees on each frame of the initial infrared sequence of burning torch. It was shown that the pixels quantity distribution has the bimodal distribution law and can be described by three local extremes coordinates: two maximums and a minimum located between them. The pixels that have relative degrees values in the range from 520 degrees to the value of the minimum’s abscissa and from the value of the minimum’s abscissa to 560 degrees relatively form two separate zones on the burning torch visualization. It was demonstrated that time-domain series constructed from frame-by-frame calculated local extremes coordinates of the P(T) distributions are stationary random sequences. This result allows to use these time-domain series as quantitative parameters of the torch combustion. It was shown that the local minimum’s abscissa value of the P(T) distribution with a relative error of 2.8 % is a constant value equal to 536.3 relative degrees. This allows to count the pixels quantity of each of the separate zones without using time-consuming Rosenblatt – Parzen estimation and run data processing in real time. © 2020 National Research Nuclear University. All rights reserved

    Pulsating combustion: Theoretical and empirical substantiation of ecological effect

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    There are two primary parameters that characterize operation of modern energy generation units that burn fuel, namely - unit efficiency and the amount of noxious emissions. Usually units that operate at the maximum efficiency produce maximum potential emissions of noxious substances (as NOx) into the atmosphere. This work provides theoretical substantiation for control of the combustion process by superimposing controlled irregularities to the fuel supply rate in order to suppress NOx generation while retaining the unit's technical parameters and cost efficiency. The substantiation uses known empirically obtained NOx generation dependency from the air excess ratio. Evaluation of the generated NOx content was performed using numerical integration of the composed time sequences describing changes in the NOx concentration in the combustion products for various types of control actions. Evaluation of bands of operating frequencies for the proposed method of combustion control are presented. The proposed theoretical substantiation made it possible to determine conditions and technics for experimental work. © 2017 Author(s)

    Research of impact input rate random variations on macroscopic characteristics of non-stationary queuing system

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    The results of research of input stream rate random variations influence on the macroscopic characteristics of a nonstationary queuing system (NQS) are discussed in this paper. Statistical information obtained during the football match between the football clubs "Krylia Sovetov" and "Dynamo" at the stadium "Metallurg" in Samara is available. The characteristics of the stochastic component of the variation in the input rate were chosen on the basis of this information. The probability density function and the cumulative distribution function of random variations in the input rate of applications were estimated using the Rosenblatt-Parzen approximation. NQ's characteristics was studied such as the maximum queue length, the maximum waiting time in the queue, the time point at which the maximum queue length is reached, and the time point at which waiting time in the queue the longest, the number of visitors who entered at the time of the match beginning, the time needed to service the entire queue. The results of the statistical simulation shown that taking into account the random component of the variation input rate does not affect this macroscopic characteristics. © Published under licence by IOP Publishing Ltd

    Serial and Parallel Implementations of Hybrid Fluid Model of Information Flows in Networks with Complex Topology

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    This paper is dedicated to the issue of modeling information flows in networks with complex topologies and it describes a comparison of the sequential (written in the MATLAB language) and parallel (based on GPGPU technology) software implementations of the hybrid fluid model (HFM) of Internet traffic. Obtained performance estimates of both software implementations indicate a higher performance of parallel software implementation HFM. The directions of further research, the results of which will be the basis for the later development of parallel software implementation HFM are proposed
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