Path Integral over Reparametrizations: Levy Flights versus Random Walks

We investigate the properties of the path integral over reparametrizations (= the boundary value of the Liouville field in open string theory). Discretizing the path integral, we apply the Metropolis-Hastings algorithm to numerical simulations of a proper (subordinator) stochastic process and find that typical trajectories are not Brownian but rather have discontinuities of the type of Levy's flights. We study a fractal structure of these trajectories and show that their Hausdorff dimension is zero. We confirm thereby the discretization and heuristic consideration of QCD scattering amplitudes by analytical and numerical calculations. We also perform Monte Carlo simulations of the path integral over reparametrization in the effective-string ansatz for a circular Wilson loop and discuss their subtleties associated with the discretization of Douglas' functional.Comment: 22pp., RevTex, 9 figures; v2: sect.IV modified; v3: minor changes, to appear in Nucl. Phys.

Study of the thermal diffusion behavior of simple binary mixtures

The Soret effect was discovered more than 150 years ago and has been studied in the meantime in gaseous mixtures, mixtures of simple molecules, polymer solutions and colloidal dispersions. The studies cover three main directions: experimental measurements, computer simulations and theoretical predictions of the Soret coefficient. Some progress has been achieved with theoretical calculation of ST for gas mixtures with Chapman-Enskog theory [63, 173]. The reasonable agreement with experiment was found. On the other hand, for the mixtures of simple molecules typically it is not even possible to predict the correct sign of ST due to the lack of accuracy of the chosen equation of state (EOS), calibrated mainly for use in the chemical and petroleum industry [11]. Several rules of thumb were proposed for simple liquid mixtures. It was found that the Soret effect is a function of the difference in mass, size, moment of inertia and vaporization enthalpy of the two mixing partners. Precise phenomenological expressions for ST were proposed for mixtures of Lennard-Jones particles in RNEMD simulations [126, 56] and for mixtures of benzene in cyclohexane in experiment [36], which are useful for simple molecular mixtures. In this thesis we studied the thermal diffusion behavior of binary mixtures of spherical, chain-like and associated molecules. Experiments were performed using the thermal diffusion Rayleigh scattering technique (TDFRS) and the thermal lens method (TL). For some of the mixtures we calculated the Soret coefficient using reverse non-equilibrium molecular dynamic simulations (RNEMD). Obtained results were analyzed in the framework of thermodynamic theories, particular attention has been given to comparison with other experimental techniques

Analytical method for parameterizing the random profile components of nanosurfaces imaged by atomic force microscopy

The functional properties of many technological surfaces in biotechnology, electronics, and mechanical engineering depend to a large degree on the individual features of their nanoscale surface texture, which in turn are a function of the surface manufacturing process. Among these features, the surface irregularities and self-similarity structures at different spatial scales, especially in the range of 1 to 100 nm, are of high importance because they greatly affect the surface interaction forces acting at a nanoscale distance. An analytical method for parameterizing the surface irregularities and their correlations in nanosurfaces imaged by atomic force microscopy (AFM) is proposed. In this method, flicker noise spectroscopy - a statistical physics approach - is used to develop six nanometrological parameters characterizing the high-frequency contributions of jump- and spike-like irregularities into the surface texture. These contributions reflect the stochastic processes of anomalous diffusion and inertial effects, respectively, in the process of surface manufacturing. The AFM images of the texture of corrosion-resistant magnetite coatings formed on low-carbon steel in hot nitrate solutions with coating growth promoters at different temperatures are analyzed. It is shown that the parameters characterizing surface spikiness are able to quantify the effect of process temperature on the corrosion resistance of the coatings. It is suggested that these parameters can be used for predicting and characterizing the corrosion-resistant properties of magnetite coatings.Comment: 7 pages, 3 figures, 2 tables; to be published in Analys

Loop corrections to the sphaleron transition rate in the minimal standard model

The baryon number dissipation rate due to sphaleron transitions at high temperatures in the minimal standard model is evaluated. We find that this rate can be considerably suppressed by one loop contributions of bosonic and fermionic fluctuations which are particularly important for a small mass of the Higgs boson and a large top quark mass. Fixing the latter to its recently stated value of 174 GeV the complete erasure of the baryon asymmetry is prevented within the framework of the minimal standard model if the Higgs mass is less than about 66 GeV.Comment: 11 pages (LaTex) plus 2 figures (uuencoded postscript files); RUB-TPII-05/9

Anomalous diffusion in the dynamics of complex processes

Anomalous diffusion, process in which the mean-squared displacement of system states is a non-linear function of time, is usually identified in real stochastic processes by comparing experimental and theoretical displacements at relatively small time intervals. This paper proposes an interpolation expression for the identification of anomalous diffusion in complex signals for the cases when the dynamics of the system under study reaches a steady state (large time intervals). This interpolation expression uses the chaotic difference moment (transient structural function) of the second order as an average characteristic of displacements. A general procedure for identifying anomalous diffusion and calculating its parameters in real stochastic signals, which includes the removal of the regular (low-frequency) components from the source signal and the fitting of the chaotic part of the experimental difference moment of the second order to the interpolation expression, is presented. The procedure was applied to the analysis of the dynamics of magnetoencephalograms, blinking fluorescence of quantum dots, and X-ray emission from accreting objects. For all three applications, the interpolation was able to adequately describe the chaotic part of the experimental difference moment, which implies that anomalous diffusion manifests itself in these natural signals. The results of this study make it possible to broaden the range of complex natural processes in which anomalous diffusion can be identified. The relation between the interpolation expression and a diffusion model, which is derived in the paper, allows one to simulate the chaotic processes in the open complex systems with anomalous diffusion.Comment: 47 pages, 15 figures; Submitted to Physical Review

Booleovská faktorová analýza atraktorovou neuronovou sítí

Import 23/08/2017Methods for the discovery of hidden structures of high-dimensional binary data rank among the most important challenges facing the community of machine learning researchers at present. There are many approaches in the literature that try to solve this hitherto rather ill-defined task. The Boolean factor analysis (BFA) studied in this work represents a hidden structure of binary data as Boolean superposition of binary factors complied with the BFA generative model of signals, and the criterion of optimality of BFA solution is given. In these terms, the BFA is a well-defined task completely analogous to linear factor analysis. The main contributions of the dissertation thesis are as follows: Firstly, an efficient BFA method, based on the original attractor neural network with increasing activity (ANNIA), which is subsequently improved through a combination with the expectation-maximization method(EM),so LANNIA method has been developed. Secondly, the characteristics of the ANNIA that are important for LANNIA and ANNIA methods functioning were analyzed. Then the functioning of both methods was validated on artificially generated data sets. Next, the method was applied to real-world data from different areas of science to demonstrate their contribution to this type of analysis. Finally, the BFA method was compared with related methods, including applicability analysis.Jednou z nejdůležitějších výzev současnosti, která stojí před komunitou badatelů z oblasti strojového učení je výzkum metod pro analýzu vysoce-dimenzionálních binárních dat s cílem odhalení jejich skryté struktury. V literatuře můžeme nalézt mnoho přístupů, které se snaží tuto doposud poněkud vágně definovanou úlohu řešit. Booleovská Faktorová Analýza (BFA), jež je předmětem této práce, předpokládá, že skrytou strukturu binárních dat lze reprezentovat jako booleovskou superpozici binárních faktorů tak, aby co nejlépe odpovídala generativnímu modelu signálů BFA a danému kritériu optimálnosti. Za těchto podmínek je BFA dob��e definovaná úloha zcela analogická lineární faktorové analýze. Hlavní přínosy disertační práce, jsou následující: Za prvé byl vyvinut efektivní způsob BFA založený na původní atraktorové neuronové síti s rostoucí aktivitou (ANNIA), která byla následně zlepšena kombinací s metodou expectation–maximization (EM)a tak vytvo5ena metoda LANNIA. Dále byly provedeny analýzy charakteristik ANNIA, které jsou důležité pro fungování obou metod. Funkčnost obou metod byla také ověřena na uměle vytvořených souborech dat pokrývajících celou škálu parametrů generativního modelu. Dále je v práci ukázáno použití metod na reálných datech z různých oblastí vědy s cílem prokázat jejich přínos pro tento typ analýzy. A konečně bylo provedeno i srovnání metod BFA se podobnými metodami včetně analýzy jejich použitelnosti.460 - Katedra informatikyvyhově

Cosmological Production of Vector Bosons and Cosmic Microwave Background Radiation

The intensive cosmological creation of vector W, Z- bosons in the cosmological model with the relative units is considered. Field theoretical models are studied, which predict that the CMB radiation and the baryon matter in the universe can be products of decay and annihilation processes of these primordial bosons.Comment: 31 pages, 1 figur

Удосконалення системи управління персоналом з урахуванням досвіду зарубіжних країн на прикладі концерну Hilding Anders

Робота публікується згідно наказу Ректора НАУ від 27.05.2021 р. №311/од «Про розміщення кваліфікаційних робіт здобувачів вищої освіти в репозиторії університету». Керівник проекту: професор Кириленко Оксана МиколаївнаPersonnel management is recognized as one of the most important spheres of enterprise life, capable of increasing its efficiency many times over, and the very concept of personnel management at the enterprise is considered in a rather wide range: from economic-statistical to philosophical-psychological. The personnel management system ensures continuous improvement of methods of work with personnel and the use of achievements of domestic and foreign science, the best production experienceУправління персоналом визнано однією з найважливіших сфер життєдіяльності підприємства, здатною багаторазово підвищити його ефективність, а саме поняття управління персоналом на підприємстві розглядається в досить широкому діапазоні: від економіко-статистичного до філософського. -психологічний. Система управління персоналом забезпечує постійне вдосконалення методів роботи з персоналом і використання досягнень вітчизняної та зарубіжної науки, кращого виробничого досвіду