Journal articles on the topic 'Non-polynomial dependence'
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1
Severa, Libor, Jaroslav Buchar, Šárka Nedomová, and Květoslava Šustová. "Rheological profile of raw whey." Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 58, no. 1 (2010): 167–74. http://dx.doi.org/10.11118/actaun201058010167.
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The results of raw whey rheological behavior investigation – particularly viscosity, dependence on temperature, time, and share rate, are presented. The whey samples have been examined under temperature ranging from 17 to 90 °C and under share rate ranging from 0.34 to 68 s−1. The measurements have been performed using rotary digital viscometer (concentric cylinders geometry). The material was found to be temperature dependent (non-linearly), time dependent and shear thinning. Received data have been successfully characterized by several mathematical models (power, exponential, and polynomial) in MATLAB® software with satisfying correlations between experimental and computed results. Following correlations have been achieved: temperature dependence with r2= 0.993 using polynomial model, time dependence with r2= 0.985 using power model, and shear thinning behavior r2= 0.998 using power model. The results are quite useful for practical design of technological equipment such as pumps and piping.
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Stanciu, Ioana. "Study of Rheological Behavior of Olive Oil Used as Biodegradable Lubricant." Oriental Journal Of Chemistry 37, no. 5 (October 30, 2021): 1248–51. http://dx.doi.org/10.13005/ojc/370533.
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In this article, based on experimental data, we obtained three dependence relations of dynamic viscosity versus temperature by polynomial and exponential fitting. The correlation coefficients have values close to unity which proves that the obtained relations accurately describe the non-Newtonian behavior of olive oil.
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Kharitonov, I. A., Regina V. Rodyakina, and A. L. Goncharov. "Investigation of Magnetic Properties of Various Structural Classes Steels in Weak Magnetic Fields Characteristic for Generation of Thermoelectric Currents in Electron Beam Welding." Solid State Phenomena 299 (January 2020): 1201–7. http://dx.doi.org/10.4028/www.scientific.net/ssp.299.1201.
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The results of studies of magnetic and thermoelectric properties of pearlite, martensitic and austenitic steels, as well as cobalt and nickel based alloys are presented. The magnetization curves for materials from among the studied ones, as well as dependences of absolute thermoelectric power on the material temperature, are obtained. It was found that for ferromagnetic substances in weak magnetic fields the dependence of magnetic induction on the magnetic field strength is non-linear. This allows to conclude that magnetic permeability of such medium is not a constant, but can be described, for example, by a third-order polynomial.
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Ramesh, K. P., J. Ramakrishna, K. S. Suresh, and C. Raghavendra Rao. "Pressure Dependence of the Chlorine NQR in Chloro Pyridines." Zeitschrift für Naturforschung A 55, no. 1-2 (February 1, 2000): 111–16. http://dx.doi.org/10.1515/zna-2000-1-219.
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The 35CI NQR frequency (υQ) and spin lattice relaxation time (T1 ) in 2,6-dichloropyridine, 2 amino 3,5-dichloropyridine and 6 chloro 2-pyridinol have been measured as a function of pressure up to 5.1 kbar at 300 K, and the data have been analysed to estimate the temperature coefficients of the NQR frequency at constant volume. All the three compounds show a non linear variation of the NQR frequency with pressure which can be described by a 2nd order polynomial in pressure. The rate of change of the NQR frequency with pressure is positive and decreases with increasing pressure. The spin lattice relaxation time T1, in all the three compounds shows a small increase with pressure, indicating that the relaxation is mainly due to the torsional motions.
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MARCOLLI, MATILDE, and JESSICA SU. "ARITHMETIC OF POTTS MODEL HYPERSURFACES." International Journal of Geometric Methods in Modern Physics 10, no. 04 (March 6, 2013): 1350005. http://dx.doi.org/10.1142/s0219887813500059.
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We consider Potts model hypersurfaces defined by the multivariate Tutte polynomial of graphs (Potts model partition function). We focus on the behavior of the number of points over finite fields for these hypersurfaces, in comparison with the graph hypersurfaces of perturbative quantum field theory defined by the Kirchhoff graph polynomial. We give a very simple example of the failure of the "fibration condition" in the dependence of the Grothendieck class on the number of spin states and of the polynomial countability condition for these Potts model hypersurfaces. We then show that a period computation, formally similar to the parametric Feynman integrals of quantum field theory, arises by considering certain thermodynamic averages. One can show that these evaluate to combinations of multiple zeta values for Potts models on polygon polymer chains, while silicate tetrahedral chains provide a candidate for a possible occurrence of non-mixed Tate periods.
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Bréhier, Charles-Edouard. "Approximation of the invariant distribution for a class of ergodic SPDEs using an explicit tamed exponential Euler scheme." ESAIM: Mathematical Modelling and Numerical Analysis 56, no. 1 (January 2022): 151–75. http://dx.doi.org/10.1051/m2an/2021089.
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We consider the long-time behavior of an explicit tamed exponential Euler scheme applied to a class of parabolic semilinear stochastic partial differential equations driven by additive noise, under a one-sided Lipschitz continuity condition. The setting encompasses nonlinearities with polynomial growth. First, we prove that moment bounds for the numerical scheme hold, with at most polynomial dependence with respect to the time horizon. Second, we apply this result to obtain error estimates, in the weak sense, in terms of the time-step size and of the time horizon, to quantify the error to approximate averages with respect to the invariant distribution of the continuous-time process. We justify the efficiency of using the explicit tamed exponential Euler scheme to approximate the invariant distribution, since the computational cost does not suffer from the at most polynomial growth of the moment bounds. To the best of our knowledge, this is the first result in the literature concerning the approximation of the invariant distribution for SPDEs with non-globally Lipschitz coefficients using an explicit tamed scheme.
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WOLF, THOMAS. "A comparison of four approaches to the calculation of conservation laws." European Journal of Applied Mathematics 13, no. 2 (April 2002): 129–52. http://dx.doi.org/10.1017/s0956792501004715.
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The paper compares computational aspects of four approaches to compute conservation laws of single Differential Equations (DEs) or systems of them, ODEs and PDEs. The only restriction, required by two of the four corresponding computer algebra programs, is that each DE has to be solvable for a leading derivative. Extra constraints for the conservation laws can be specified. Examples include new conservation laws that are non-polynomial in the functions, that have an explicit variable dependence and families of conservation laws involving arbitrary functions. The following equations are investigated in examples: Ito, Liouville, Burgers, Kadomtsev–Petviashvili, Karney–Sen–Chu–Verheest, Boussinesq, Tzetzeica, Benney.
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MATAR, S., J. TEICHMANN, and P. MOHN. "MAGNETOVOLUME EFFECTS IN Fe3Pt." International Journal of Modern Physics B 07, no. 01n03 (January 1993): 691–94. http://dx.doi.org/10.1142/s0217979293001451.
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Equilibrium values of the energy for the magnetic and non-magnetic structures were derived for Fe3Pt using the scalar relativistic ASW method. The stable ground state is found to be ferromagnetic. Calculations were extended to obtain total energy curves as a function of moment and volume via the FSM method. Results were fitted using a polynomial in M and V within a Landau-Ginzburg model of spin fluctuations. Relevant properties to Invar such as the magnetic contribution to the thermal expansion coefficient and the critical pressure for the disappearance of magnetism and its pressure dependence were derived.
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Wang, Haopeng, Xueyan Liu, Panos Apostolidis, and Tom Scarpas. "Non-Newtonian Behaviors of Crumb Rubber-Modified Bituminous Binders." Applied Sciences 8, no. 10 (September 29, 2018): 1760. http://dx.doi.org/10.3390/app8101760.
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Crumb rubber-modified bitumen (CRMB) has been utilized in the asphalt paving industry for decades due to its various benefits. The complex interaction between bitumen and crumb rubber as well as the addition of warm-mix additives makes the typical laws of Newtonian fluids insufficient to describe the behaviors of highly modified bituminous binders. To systematically explore the non-Newtonian behaviors of CRMB, a dynamic shear rheometer was utilized to apply shear loading on the samples at various temperatures and shear rates. Results show that the viscosity of different binders are highly temperature- and shear rate-dependent, while highly modified binders exhibit more obvious shear-thinning behaviors at certain temperatures. With the help of zero shear viscosity and yield stress, the shear-thinning behaviors of non-Newtonian binders can be sufficiently characterized. The Arrhenius equation is invalid to describe viscosity-temperature characteristics of bitumen in the non-Newtonian region. A second-order polynomial function was proposed to characterize the viscosity-temperature dependence with a high correlation degree.
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Ruska, Ruslana. "MODELLING THE DYNAMICS OF PENSION CONTRIBUTIONS ACCUMULATION IN NON-GOVERNMENTAL PENSION FUNDS." Economic Analysis, no. 28(4) (2018): 106–13. http://dx.doi.org/10.35774/econa2018.04.106.
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Introduction. Pension provision in any country depends both on the state of the national economy and on the state regulation of social processes. The solidarity pension system in Ukraine does not provide a decent standard of living. Alternative, which allows creating an additional source of pension benefits, which are guaranteed by the state, and reducing the financial burden on the state, are non-state pension funds. Non-state pension funds provide non-state pension provision services by individualizing the accumulation of funds. Their main purpose is to ensure that people receive additional mandatory state pension insurance payments. After analysing different approaches to improving the system of non-state pension funds, the main indicators influencing pension payments are revealed. Purpose. The article aims to model the dynamics of key indicators, on which the payment of pensions in non-state pension funds depends. Methodology. In the process of writing a paper, we have used a number of scientific methods. The system approach is used as one of the main methods of scientific research. The MARSPline module is a component of Data Mining technology in the application package Statistica, techniques of mathematical modelling, in particular approximating polynomials in the process of modelling the dynamics of receipts and payments. The use of actuarial methods helps show how to determine the accumulated amount on individual accounts of participants in non-state pension funds. Results. Different methods and approaches to the evaluation of the activity of non-state pension funds have been analysed. The use of the sixth grade polynomial has made it possible to follow the dynamics of contracting for subsequent periods. It is determined by actuarial methods of accumulated amount on individual pension accounts with different options for contributing and charges interest thereon, allowing depositors to predict the amount of their investments. Using the MARSPline module Statistics program is constructed: a regression model of the dependence of a retirement asset on one person from contributions and investments of investments; Dependence of pension payments on contributions to individual accounts, income from investment of assets, expenses and the number of paid pensions, which allows calculation of future payments to participants, is revealed. The application of the fourth-level approximation polynomial makes it possible to determine the amounts of future retirement benefits in dynamics.
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VIJAYAKUMAR, V. "Absolute temperature directly from plank’s profile: A simulation." Journal of Ultra Scientist of Physical Sciences Section A 33, no. 2 (February 24, 2021): 9–19. http://dx.doi.org/10.22147/jusps-a/330201.
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The measured thermal radiation from a material surface will, in general, have a wave length (\lambda) dependent scale-factor to the Planck profile (PT) from the contributions of the emissivity (Є\lambda) of the surface, the response function (A\lambda) of the measurement setup, and the emission via non-Plank processes. For obtaining the absolute temperature from such a profile, a procedure that take care of these dependencies and which relay on a temperature grid searchis proposed. In the procedure, the deviation between the Plank profiles at various temperatures and the measured spectrum that is made equal to it at a selected wavelength, by scaling, is used. The response function (A\lambda) is eliminated at the measurement stage and the polynomial dependence of the remnant scale factor mostly dominated by Є\lambda) i s extracted from the measured spectrum by identifying its optimal \lambda dependence. It is shown that when such a computation is carried out over a temperature grid, the absolute temperature can be identified from the minimum of the above deviation. Here, search for T and Є\lambda) d elinked, unlike in the leastsquare approaches that are normally employed. Code that implements the procedure is tested with simulated Planck profile to which different viable values of Є\lambda) a nd noise is incorporated. It shown that if the \lambda dependence of scale-factor is not too high, the absolute temperature can be recovered. A large \lambda dependent scale-factor and the consequent possible error in the temperature obtained can also be identified.
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Cocola, Jorio, Paul Hand, and Vladislav Voroninski. "No Statistical-Computational Gap in Spiked Matrix Models with Generative Network Priors." Entropy 23, no. 1 (January 16, 2021): 115. http://dx.doi.org/10.3390/e23010115.
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We provide a non-asymptotic analysis of the spiked Wishart and Wigner matrix models with a generative neural network prior. Spiked random matrices have the form of a rank-one signal plus noise and have been used as models for high dimensional Principal Component Analysis (PCA), community detection and synchronization over groups. Depending on the prior imposed on the spike, these models can display a statistical-computational gap between the information theoretically optimal reconstruction error that can be achieved with unbounded computational resources and the sub-optimal performances of currently known polynomial time algorithms. These gaps are believed to be fundamental, as in the emblematic case of Sparse PCA. In stark contrast to such cases, we show that there is no statistical-computational gap under a generative network prior, in which the spike lies on the range of a generative neural network. Specifically, we analyze a gradient descent method for minimizing a nonlinear least squares objective over the range of an expansive-Gaussian neural network and show that it can recover in polynomial time an estimate of the underlying spike with a rate-optimal sample complexity and dependence on the noise level.
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Nosov, A. P., A. A. Akhrem, V. Z. Rakhmankulov, and K. V. Yuzhanin. "Computational Complexity Analysis of Decomposition Methods of OLAP Hyper-cubes of Multidimensional Data." Mathematics and Mathematical Modeling, no. 4 (December 25, 2020): 52–64. http://dx.doi.org/10.24108/mathm.0420.0000221.
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The paper investigates the problems of reduction (decomposition) of multidimensional data models in the form of hypercube OLAP structures. OLAP data processing does not allow changes in the dimension of space. With the increase in data volumes, the productivity of computing cubic structures decreases. Methods for reducing large data cubes to sub-cubes with smaller volumes can solve the problem of reducing computing performance.The reduction problems are considered for cases when the cube lattice has already determined criteria aggregation, and the cube decomposition into smaller cubes is needed to reduce the computation time of the full lattice when dynamically changing data in the cube.The objective of the paper is to find conditions for reducing the computational complexity of solving data analysis problems by reduction methods, to obtain exact quantitative boundaries for reducing the complexity of decomposition methods from the class of polynomial degrees of complexity, to establish the nature of the dependence of computational performance on the structural properties of a hypercube, and to determine the quantitative boundaries of computational performance for solving decomposition problems of data aggregation .The study of the computational complexity of decomposition methods for the analysis of multidimensional hyper-cubes of polynomial-logarithmic and polynomial degrees of complexity is carried out. An exact upper limit is found for reducing the complexity of decomposition methods for analyzing the initial OLAP - data hypercube with respect to non-decomposition ones and based on them criteria are proved for the effective application of reduction methods for analyzing hypercube structures in comparison with traditional non-reduction methods.Examples of decomposition methods of cube structures are presented, both reducing and increasing computational complexity in comparison with calculations using the full model.The results obtained can be used in processing and analysis of information arrays of hypercube structures of analytical OLAP-systems belonging to the BigData class, or ultra-large computer multidimensional data systems.
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IRON, DAVID, and MICHAEL J. WARD. "THE STABILITY AND DYNAMICS OF HOT-SPOT SOLUTIONS TO TWO ONE-DIMENSIONAL MICROWAVE HEATING MODELS." Analysis and Applications 02, no. 01 (January 2004): 21–70. http://dx.doi.org/10.1142/s0219530504000291.
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The stability and dynamics of hot-spot solutions to two different classes of scalar, nonlocal, singularly perturbed reaction-diffusion equations is analyzed. These problems arise in the modeling of the microwave heating of a ceramic material placed in a single-mode resonant cavity. For the first model, where the coefficients in the differential operator are spatially homogeneous, an explicit characterization of metastable hot-spot behavior is given in the limit of small thermal diffusivity ε. For the second model, where the differential operator has a spatially inhomogeneous term resulting from the variation in the electric field along the ceramic sample, a hot-spot solution is shown to propagate on an algebraically long time-scale of order O(ε-2) towards the point of maximum field strength. The electrical conductivity of the sample is taken to have either an exponential or a polynomial dependence on the temperature. For the polynomial form, the stability of a hot-spot profile is determined from the eigenvalues of a non-self-adjoint eigenvalue problem. It is proved that a general class of eigenvalue problems of this type may have complex conjugate eigenvalues in the limit ε→0. A careful proof of the stability of the hot-spot profile is given for this delicate case.
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Topolsky, N. G., S. Yu Butuzov, V. Ya Vilisov, and V. L. Semikov. "A model of response efficiency in the hierarchical control system based on the assessment of readiness of fire departments." Pozharovzryvobezopasnost/Fire and Explosion Safety 30, no. 5 (December 6, 2021): 42–57. http://dx.doi.org/10.22227/0869-7493.2021.30.05.42-57.
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Introduction. The readiness of all levels of subsystems that comprise the Unified State System for Emergency Prevention and Liquidation (USSEPL) is one of the most important characteristics that determine its effectiveness. To support decision-making at the upper levels of the management hierarchy, it is important to have a set of models that adequately represent the dependence between key response efficiency indicators and particular indicators of lower levels of the system (fire and rescue departments). In most cases, a regulatory approach to the construction of such models, by virtue of which analysts set their structure and parameters, turns out to be unproductive due to their non-adaptive nature in the context of dynamically changing external conditions and technological capabilities of modern devices. The use of an approach based on solving inverse problems that close the feedback loop and provide for an adaptive adjustment of parameters and the structure of models, ensures the current adequacy of models amid changing conditions.The relevance of the study lies in the development of a technology for constructing polynomial models that allow to assess the USSEPL response effectiveness based on estimated indicators of readiness of subsystems at lower levels obtained using expert evaluation techniques (testing) by means of internal control.Goals and objectives. The aim of the work is to build and test the technology for developing analytical polynomial models that allow to adequately assess performance indicators of the USSEPL response depending on the readiness indicators of lower-level subsystems (fire and rescue departments). In compliance with this goal, the tasks of choosing the type of model and methods of obtaining the necessary initial data are also set.Methods. The study uses methods of analysis of hierarchically organized systems, mathematical statistics, simulation modelling, and methods of expert evaluation. The research is backed by materials from domestic and foreign publications.Results and discussion. The proposed method of constructing an efficiency model of the USSEPL operation, relying on the readiness of subsystems, serves as the basis for constructing models that can take into account other indicators of subsystems.Conclusions. The solution to the problem of constructing a polynomial model, that features dependence between the USSEPL response efficiency and lower-level readiness indicators, serves as the basis for other similar models that will support decision making systems.
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Panferov, Anatolii Dmitrievich, and Alexey Vladimirovich Makhankov. "Simulation of the effect of short optical pulses on graphene." Program Systems: Theory and Applications 10, no. 1 (2019): 47–58. http://dx.doi.org/10.25209/2079-3316-2019-10-1-47-58.
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The interaction of high-frequency pulsed electric fields with graphene is currently the subject of intense research. The paper presents the results of testing a software system for modeling such processes using the example of ultrashort laser pulses of the optical range with different polarizations. The authors develop the system on a base of a new theoretical approach based on the quantum kinetic equation. The approach contains a computational model for a new system of ordinary differential equations with non-linearly dependent on time and problem parameters coefficients. The need to analyze the behavior of solutions of this system of equations in the field of changing several parameters leads to the polynomial computational complexity. The lack of knowledge of the nature of the parametric dependence of solutions requires several iterations of the choice of covering grids. The paper describes the adaptation of this modeling system for use in massively parallel computing systems.
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BUCUR, ALINA, EDGAR COSTA, CHANTAL DAVID, JOÃO GUERREIRO, and DAVID LOWRY–DUDA. "Traces, high powers and one level density for families of curves over finite fields." Mathematical Proceedings of the Cambridge Philosophical Society 165, no. 2 (July 31, 2017): 225–48. http://dx.doi.org/10.1017/s030500411700041x.
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AbstractThe zeta function of a curve C over a finite field may be expressed in terms of the characteristic polynomial of a unitary matrix ΘC. We develop and present a new technique to compute the expected value of tr(ΘCn) for various moduli spaces of curves of genus g over a fixed finite field in the limit as g is large, generalising and extending the work of Rudnick [Rud10] and Chinis [Chi16]. This is achieved by using function field zeta functions, explicit formulae, and the densities of prime polynomials with prescribed ramification types at certain places as given in [BDF+16] and [Zha]. We extend [BDF+16] by describing explicit dependence on the place and give an explicit proof of the Lindelöf bound for function field Dirichlet L-functions L(1/2 + it, χ). As applications, we compute the one-level density for hyperelliptic curves, cyclic ℓ-covers, and cubic non-Galois covers.
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Linß, Sebastian, Philipp Schorr, and Lena Zentner. "General design equations for the rotational stiffness, maximal angular deflection and rotational precision of various notch flexure hinges." Mechanical Sciences 8, no. 1 (March 15, 2017): 29–49. http://dx.doi.org/10.5194/ms-8-29-2017.
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Abstract. Notch flexure hinges are often used as revolute joints in high-precise compliant mechanisms, but their contour-dependent deformation and motion behaviour is currently difficult to predict. This paper presents general design equations for the calculation of the rotational stiffness, maximal angular elastic deflection and rotational precision of various notch flexure hinges in dependence of the geometric hinge parameters. The novel equations are obtained on the basis of a non-linear analytical model for a moment and a transverse force loaded beam with a variable contour height. Four flexure hinge contours are investigated, the semi-circular, the corner-filleted, the elliptical, and the recently introduced bi-quadratic polynomial contour. Depending on the contour, the error of the calculated results is in the range of less than 2 % to less than 16 % for the suggested parameter range compared with the analytical solution. Finite elements method (FEM) and experimental results correlate well with the predictions based on the comparatively simple and concise design equations.
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Sheng, Hongwei, Ping Wang, and Chenglong Tang. "Predicting Mechanical Properties of Cold-Rolled Steel Strips Using Micro-Magnetic NDT Technologies." Materials 15, no. 6 (March 15, 2022): 2151. http://dx.doi.org/10.3390/ma15062151.
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Multiple micro-magnetic non-destructive testing (NDT) technologies are suitable candidates for predicting the mechanical properties of cold-rolled steel strips. In this work, based on magnetic domain dynamics behavior and magnetization theory, the correlation between electromagnetic characteristics extracted by multiple micro-magnetic NDT technologies and the influence factors was investigated. It was found that temperature and tension can subsequently affect the electromagnetic parameters by altering the domain structure and domain walls’ motion properties. Pearson’s correlation coefficients were employed to reflect the dependence of micromagnetic characteristics on influencing factors. The lift-off was determined as the largest influence factor among influence factors. A pseudo-static detection was reached by polynomial fitting, which could eliminate the influence of lift-off on the detection results. The number of training models was optimized, and the detection accuracy was improved via the improved Generalized Regression Neural Network (GRNN) model, based on the Gaussian Mixture Clustering (GMC) algorithm.
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Prokopenkov, Vladymyr. "POLYNOMIAL ALGORITHM FOR FINDING A HAMILTONIAN CYCLE ON A GRAPH." Bulletin of NTU "KhPI". Series: Strategic management, portfolio, program and project management, no. 1(3) (April 17, 2021): 55–65. http://dx.doi.org/10.20998/2413-3000.2021.3.8.
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The subject of research is the solution of the problem of finding a Hamiltonian cycle on a graph, which in discrete mathematics belongs to the NP complexity class and still retains interest. The aim of this work is to develop a new algorithm for solving this problem, which guarantees finding the optimal solution with polynomial time. In [1], an analysis of the current state of the problem was performed, the shortcomings of existing methods of solving were noted, and new principles and method of finding solution were presented. Known methods for solving the problem are based on the implementation of a search of possible solutions or on intuitive heuristics. Enumeration methods of solutions are unacceptable in terms of costs, since they characterized by non-polynomial time. Heuristic methods are satisfactory in time, but they do not guarantee finding the optimal solution. The popularity of enumeration methods is explained by the linear simplicity of searching in a pre-known set of acceptable solutions to the problem. But the factorial dependence of the power of the set of solutions (n-1)! from the number of vertices of the graph n makes it impossible to use such methods for large-size problems in practice. The desire to significantly reduce time costs leads to attempts to reasonably reduce the enumeration set or to the development of various heuristics, which actually indicates that it is impossible to formulate conditions for finding the optimal solution to the problem as a whole. This article describes the conditions that determine the optimal solution of the problem and a polynomial algorithm for solving the problem that embodies the described method. Finding the optimal solution to the problem is reduced to finding a closed path in a new graph of shortest paths. The shortest paths graph built on the original graph of the problem by using Dijkstra's algorithm. The enumeration set for determining the optimal solution of the problem consists of solutions that are constructed from each vertex of the source graph in the shortest paths graph. The size of this set is estimated as n(n-1). The developed parallel algorithm guarantees finding the optimal solution, significantly reduces the initial search space, and allows you to find a solution with polynomial complexity. Testing of the program showed the efficiency of the developed method and algorithm for solving the problem.
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Marwa, Taufiq, Abdul Bashir, K. M. Husni Thamrin, Azwardi, and Imam Asngari. "THE THE SOCIO-ECONOMIC VARIABLES INFLUENCING HOUSEHOLD CONSUMPTION IN THE RURAL FARMERS LEVEL." Humanities & Social Sciences Reviews 8, no. 2 (March 15, 2020): 112–22. http://dx.doi.org/10.18510/hssr.2020.8214.
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Purpose of the study: This study investigated the socio-economic effect on household consumption of rural farmers in South Sumatera, Indonesia.
Methodology: The data used were primary data obtained from an in-depth survey of 300 farmer households. The analysis method used a quantitative approach with a polynomial regression model.
Main Findings: The finding showed that from the four independent variables estimated, there are three which have a significant effect on farmer household consumption: household income, number of family members, and education level of the household head. Despite changes in consumption patterns between food and non-food, the process of food diversification is an important task for the government, especially to reduce dependence on rice consumption.
Applications of this study: This study was conducted in South Sumatra, Indonesia in the field of agricultural economics. This study can support development planning policies in the food sector in South Sumatra.
Novelty/Originality of this study: This study focus as efforts on the policy of diversifying food consumption needs to be synergized with the development of local resource-based food products.
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Shary, Sergey P. "Data fitting problem under interval uncertainty in data." Industrial laboratory. Diagnostics of materials 86, no. 1 (January 30, 2020): 62–74. http://dx.doi.org/10.26896/1028-6861-2020-86-1-62-74.
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We consider the data fitting problem under uncertainty, which is not described by probabilistic laws, but is limited in magnitude and has an interval character, i.e., is expressed by the intervals of possible data values. The most general case is considered when the intervals represent the measurement results both in independent (predictor) variables and in the dependent (criterial) variables. The concepts of weak and strong compatibility of data and parameters of functional dependence are introduced. It is shown that the resulting formulations of problems are reduced to the study and estimation of various solution sets for an interval system of equations constructed from the processed data. We discuss in detail the strong compatibility of the parameters and data, as more practical, more adequate to the reality and possessing better theoretical properties. The estimates of the function parameters, obtained in view of the strong compatibility, have a polynomial computational complexity, are robust, almost always have finite variability, and are also only partially affected by the so-called Demidenko paradox. We also propose a computational technology for solving the problem of constructing a linear functional dependence under interval data uncertainty and take into account the requirement of strong compatibility. It is based on the application of the so-called recognizing functional of the problem solution set — a special mapping, which recognizes, by the sign of the values, whether a point belongs to the solution set and simultaneously provides a quantitative measure of this membership. The properties of the recognizing functional are discussed. The maximum point of this functional is taken as an estimate of the parameters of the functional dependency under construction, which ensures the best compatibility between the parameters and data (or their least discrepancy). Accordingly, the practical implementation of this approach, named «maximum compatibility method», is reduced to the computation of the unconditional maximum of the recognizing functional — a concave non-smooth function. A specific example of solving the data fitting problem for a linear function from measurement data with interval uncertainty is presented.
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Pejovic, Branko, Ljubica Vasiljevic, Vladan Micic, and Mitar Perusic. "Suitable model for the calculation of the correlation between the real and the average specific heat capacity and possibilities of its application." Chemical Industry 67, no. 3 (2013): 495–511. http://dx.doi.org/10.2298/hemind111104092p.
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Starting from the definition of the average specific heat capacity for chosen temperature range, the analytic dependence between the real and the mean specific heat capacities is obtained using differential and integral calculation. The obtained relation in differential form for the defined temperature range allows for the problem to be solved directly, without any special restrictions on its use. Using the obtained relation, a general model in the form of a polynomial of arbitrary degree in the function of temperature was derived, which has more suitable and faster practical application and is more general in character than the existing model. New graphical method for solving the problem is obtained based on differential geometry and using the derived equation. This may also have practical significance since many problems in thermodynamics are solved analytically and graphically. This result was used in order to obtain the amount of specific heat exchanged using an analytical model or a planimetric method. In addition, this graphical solution was used for the construction of the diagram showing the dependence between the specific heat exchanged and temperature. This diagram also gives a simple graphical procedure for the calculation of the real and the average specific heat capacity for arbitrary temperature or temperature interval. The confirmation for all graphic constructions is obtained using the differential properties between thermodynamic units. In order for the graphical solutions presented to be applicable in practice, suitable ratio coefficients have been determined for all cases. Verification of the model presented, as well as the possibilities of its application, were given using several characteristic examples of semi-ideal and real gas. Apart from linear and non-linear functions in the form of polynomials, the exponential function of the dependence between specific heat capacities and temperature was also analysed in this process.
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Prishchenko, Olga, Nadezhda Cheremskaya, and Tetyana Chernogor. "CONSTRUCTION OF MATHEMATICAL MODELS USING THE METHODS OF CORRELATION AND REGRESSION ANALYSIS." Bulletin of the National Technical University "KhPI". Series: Innovation researches in students’ scientific work, no. 2 (December 16, 2021): 29–36. http://dx.doi.org/10.20998/2220-4784.2021.02.05.
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The article discusses the construction of a mathematical model using the methods of correlation and regression analysis in determining the functional relationship between the quantities. When conducting an experiment, it is often necessary to establish the interdependence between two or more quantities in order to obtain an empirical formula. In some cases, this is a simple task, because these connections are almost obvious or known in advance. As a rule, to establish the relationship between different indicators, factors and characteristics is not a trivial task. There is a need to use some hypothesis in the form of functional dependence. In other words, it is necessary to replace this functional dependence with a fairly simple mathematical expression. Such a mathematical expression can be a linear equation or a polynomial. In order to use such experimental data to determine such a mathematical or functional relationship between variables, the methods of correlation and regression analysis are used. Correlation analysis provides an answer to the statistical hypothesis of the absence or presence of a relationship between variables with some predetermined confidence probability. Determination of the functional dependence between different values on their experimental values is carried out using regression analysis. It is based on the well-known method of least squares. Proposing one or another regression equation, the researcher determines both the very existence of the relationship between variables and its mathematical form. Regression analysis considers the relationship between the dependent quantity and non-dependent variables. This relationship is represented using a mathematical model, that is, an equation that connects the dependent and independent variables. Processing of experimental data using correlation and regression analysis allows us to build a statistical mathematical model in the form of a regression equation. Thus, the methods of correlation and regression analysis are closely related.
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Sraj, Ihab, Mohamed Iskandarani, Ashwanth Srinivasan, W. Carlisle Thacker, Justin Winokur, Alen Alexanderian, Chia-Ying Lee, Shuyi S. Chen, and Omar M. Knio. "Bayesian Inference of Drag Parameters Using AXBT Data from Typhoon Fanapi." Monthly Weather Review 141, no. 7 (July 1, 2013): 2347–67. http://dx.doi.org/10.1175/mwr-d-12-00228.1.
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Abstract The authors introduce a three-parameter characterization of the wind speed dependence of the drag coefficient and apply a Bayesian formalism to infer values for these parameters from airborne expendable bathythermograph (AXBT) temperature data obtained during Typhoon Fanapi. One parameter is a multiplicative factor that amplifies or attenuates the drag coefficient for all wind speeds, the second is the maximum wind speed at which drag coefficient saturation occurs, and the third is the drag coefficient's rate of change with increasing wind speed after saturation. Bayesian inference provides optimal estimates of the parameters as well as a non-Gaussian probability distribution characterizing the uncertainty of these estimates. The efficiency of this approach stems from the use of adaptive polynomial expansions to build an inexpensive surrogate for the high-resolution numerical model that couples simulated winds to the oceanic temperature data, dramatically reducing the computational burden of the Markov chain Monte Carlo sampling. These results indicate that the most likely values for the drag coefficient saturation and the corresponding wind speed are about 2.3 × 10−3 and 34 m s−1, respectively; the data were not informative regarding the drag coefficient behavior at higher wind speeds.
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Astolfi, Davide, and Ravi Pandit. "Multivariate Wind Turbine Power Curve Model Based on Data Clustering and Polynomial LASSO Regression." Applied Sciences 12, no. 1 (December 22, 2021): 72. http://dx.doi.org/10.3390/app12010072.
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Wind turbine performance monitoring is a complex task because of the non-stationary operation conditions and because the power has a multivariate dependence on the ambient conditions and working parameters. This motivates the research about the use of SCADA data for constructing reliable models applicable in wind turbine performance monitoring. The present work is devoted to multivariate wind turbine power curves, which can be conceived of as multiple input, single output models. The output is the power of the target wind turbine, and the input variables are the wind speed and additional covariates, which in this work are the blade pitch and rotor speed. The objective of this study is to contribute to the formulation of multivariate wind turbine power curve models, which conjugate precision and simplicity and are therefore appropriate for industrial applications. The non-linearity of the relation between the input variables and the output was taken into account through the simplification of a polynomial LASSO regression: the advantages of this are that the input variables selection is performed automatically. The k-means algorithm was employed for automatic multi-dimensional data clustering, and a separate sub-model was formulated for each cluster, whose total number was selected by analyzing the silhouette score. The proposed method was tested on the SCADA data of an industrial Vestas V52 wind turbine. It resulted that the most appropriate number of clusters was three, which fairly resembles the main features of the wind turbine control. As expected, the importance of the different input variables varied with the cluster. The achieved model validation error metrics are the following: the mean absolute percentage error was in the order of 7.2%, and the average difference of mean percentage errors on random subsets of the target data set was of the order of 0.001%. This indicates that the proposed model, despite its simplicity, can be reliably employed for wind turbine power monitoring and for evaluating accumulated performance changes due to aging and/or optimization.
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Goolak, Sergey, Viktor Tkachenko, Svitlana Sapronova, Oleksandr Spivak, Ievgen Riabov, and Oleksandr Ostroverkh. "Determination of inductances for pulsating current traction motor." Technology audit and production reserves 2, no. 1(58) (April 30, 2021): 40–43. http://dx.doi.org/10.15587/2706-5448.2021.229217.
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The object of research is a pulsating current traction motor. To improve the accuracy of its mathematical model, it is necessary to use the values of the parameters that are determined in experimental studies of the electric motor. In particular, it is important to use in the model of the electric motor inductance obtained experimentally. A method is proposed for calculating the inductance of the armature winding, main poles, additional poles and compensation winding and the total inductance of the traction motor armature circuit. The calculations are based on the results of the indirect inductance measurement method, in which the electrical values of various modes of power supply of the electric motor windings are directly measured, and the inductances are determined by auxiliary calculations. The inductances of the traction motor armature circuit have a non-linear dependence on the current flowing through them. The main difference of the study is that the measurements of the electrical parameters required for calculating the inductance are carried out over the entire range of operating currents of the windings. The essence of the proposed technique is to measure the active power in the armature winding, the winding of the main and additional poles, and the compensation winding, as well as in the armature circle as a whole when they are supplied with alternating current. According to the obtained values of active power losses and phase displacement, the corresponding reactive power losses are determined, with the help of which the inductances of the motor windings are calculated. Approbation of the methodology for calculating the conduction inductance for an electric motor of a pulsating current NB-418K6 (country of origin Russia), is used on electric locomotives of the VL80T and VL80k series (country of origin Russia). A scheme for measuring electrical parameters necessary for calculating inductance is proposed. The graphical dependences of the inductance on the armature current, built on the basis of calculations, confirmed the hypothesis about the nonlinear dependence of these inductances on the armature current. For further application of the results obtained in the simulation of the operation of the traction electric motor NB-418K6, a polynomial approximation of the total inductance of the armature circuit was performed.
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Wu, Xiaohan, Julian B. Muñoz, and Daniel Eisenstein. "A fully Lagrangian, non-parametric bias model for dark matter halos." Journal of Cosmology and Astroparticle Physics 2022, no. 02 (February 1, 2022): 002. http://dx.doi.org/10.1088/1475-7516/2022/02/002.
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Abstract We present a non-parametric Lagrangian biasing model and fit the ratio of the halo and mass densities at the field level using the mass-weighted halo field in the AbacusSummit simulations at z=0.5. Unlike the perturbative halo bias model that has been widely used in interpreting the observed large-scale structure traced by galaxies, we find a non-negative halo-to-mass ratio that increases monotonically with the linear overdensity δ1 in the initial Lagrangian space. The bias expansion, however, does not guarantee non-negativity of the halo counts, and may lead to rising halo number counts at negative overdensities. The shape of the halo-to-mass ratio is unlikely to be described by a polynomial function of δ1 and other quantities. Especially for massive halos with 6×1012 h-1 M⊙, the halo-to-mass ratio starts soaring up at δ1>0, substantially different from the predictions of the bias expansion. We show that for the halo masses we consider (M>3×1011 h-1 M⊙) a non-parametric halo-to-mass ratio as a function of δ1 and its local derivative ∇^2δ1 can recover the halo power spectra to sub-percent level accuracy for wavenumbers k=0.01-0.1 h Mpc-1 given a proper smoothing scale to filter the initial density field, even though we do not fit the power spectrum directly. However, there is mild dependence of the recovery of the halo power spectrum on the smoothing scale and other input parameters. At k<0.01 h Mpc-1 and for massive halos with M>6×1012 h-1 M⊙, our non-parametric model leads to a few percent overestimation of the halo power spectrum, indicating the need for larger or multiple smoothing scales. The halo-to-mass ratios obtained qualitatively agree with intuitions from extended Press-Schechter theory. We compare our framework to the bias expansion and discuss possible extensions.
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Vusikhis, Alexander S., Evgeny N. Selivanov, Stanislav N. Tyushnyakov, and Victor P. Chentsov. "Thermodynamic modeling of reduction of metals from B2O3-CaO-Ni(Zn,Pb,Cu)O melts carbon monoxide." Butlerov Communications 59, no. 9 (September 30, 2019): 125–31. http://dx.doi.org/10.37952/roi-jbc-01/19-59-9-125.
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Thermodynamic modeling technique is used to describe the metal reduction from oxide melt by carbon monoxide. The B2O3-CaO-MeO (Me – Ni, Zn, Pb, Cu) system, was used with periodic output of the metal phase and gases from the working body. The approach originality is that the equilibrium is determined for each single portion of the gas injected into the working body, and the metal oxides content being reduced in each calculation cycle is taken from the previous data. This approach gives qualitative possibility to make simulated processes closer to real ones. The proposed method calculations allow determining, such parameters as the oxide melt and metal phase compositions, degree of elements reduction, oxide and metal phases mass ratio, equilibrium composition of the gas, reducing ability of gas utilization degree, and others, depending on the introduced gas quantities. Reducing process modeling of Nickel, Copper, Lead and Zinc from B2O3-CaO-MeO melts gives opportunity to determine the process for each metal. Copper reducing from CuO, goes with intermediate oxide (CuO → Cu2O → Cu) formation. Reduction of Nickel (NiO → Ni), Lead (PbO → Pbs + Pbg) and Zinc (ZnO → Zng) proceeds in one stage. The temperature dependence of the non-ferrous metals content in the oxide melt, its reduction degree and reducing agent quantity introduced are described by the second-order polynomial equations. The information obtained may be useful for thermo-extraction processes prognosis during the Nickel, Copper, Lead, and Zinc extraction from non-ferrous metallurgy slag in bubbling process of oxide melt by reducing gases.
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Snellen, I. A. G., L. Guzman-Ramirez, M. R. Hogerheijde, A. P. S. Hygate, and F. F. S. van der Tak. "Re-analysis of the 267 GHz ALMA observations of Venus." Astronomy & Astrophysics 644 (December 2020): L2. http://dx.doi.org/10.1051/0004-6361/202039717.
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Context. ALMA observations of Venus at 267 GHz that show the apparent presence of phosphine (PH3) in its atmosphere have been presented in the literature. Phosphine currently has no evident production routes on the planet’s surface or in its atmosphere. Aims. The aim of this work is to assess the statistical reliability of the line detection via independent re-analysis of the ALMA data. Methods. The ALMA data were reduced the same way as in the published study, following the provided scripts. First, the spectral analysis presented in the study was reproduced and assessed. Subsequently, the spectrum, including its dependence on selected ALMA baselines, was statistically evaluated. Results. We find that the 12th-order polynomial fit to the spectral passband utilised in the published study leads to spurious results. Following their recipe, five other > 10σ lines can be produced in absorption or emission within 60 km s−1 from the PH3 1−0 transition frequency by suppressing the surrounding noise. Our independent analysis shows a feature near the PH3 frequency at a ∼2σ level, below the common threshold for statistical significance. Since the spectral data have a non-Gaussian distribution, we consider a feature at such level as statistically unreliable, which cannot be linked to a false positive probability. Conclusions. We find that the published 267 GHz ALMA data provide no statistical evidence for phosphine in the atmosphere of Venus.
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Ivanov, Sergey P. "Bulking of physically nonlinear plates under the action of dynamic shearing loads." Structural Mechanics of Engineering Constructions and Buildings 18, no. 1 (May 23, 2022): 3–10. http://dx.doi.org/10.22363/1815-5235-2022-18-1-3-10.
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The study of the stability of plates under shear under the action of dynamic loads is one of the important problems of structural mechanics. The plates are widely used in construction, mechanical engineering, shipbuilding and aircraft building. The paper presents a method for calculating plates for shear buckling, taking into account the physical nonlinearity of the material. A plate is considered under the action of a shearing dynamic load along the edges. The calculation is based on the Kirchhoff - Love hypotheses and the hypothesis of a non-linear elastic body. The plate material is assumed to be physically nonlinear. The deformation diagram is approximated as a cubic polynomial. The deflection of the plate points is determined in the form of Vlasov - Kantorovich expansions. Basic non-linear differential equations are derived using the energy method. Lagrange’s equations are used to obtain the resolving equations for plate buckling. On the basis of the developed technique, a calculation was made for the stability of a physically nonlinear square plate under the action of a shear dynamic load. The edges of the plate are hinged. The finite system of nonlinear differential equations is integrated numerically by the Runge - Kutta method. Based on the results of calculations, plots of the dependence of the relative value of the deflection of the central point of the plate on the dynamic coefficient Kd (with and without taking into account the physical nonlinearity of the material) are plotted. The influence of the degree of physical nonlinearity of the material, the parameter of the rate of change of the shear load on the criteria for the dynamic stability of a square plate is studied.
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Abdelmohssin, Faisal A. Y., and Osman M. H. El Mekki. "The Hamiltonian of f(R) gravity." Canadian Journal of Physics 99, no. 9 (September 2021): 814–19. http://dx.doi.org/10.1139/cjp-2021-0058.
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We derive conjugate momenta variable tensors and the Hamiltonian equation of the source-free f(R) gravity from first principles using the Legendre transformation of these conjugate momenta variable tensors, conjugate coordinates variables — fundamental metric tensor and its first ordinary partial derivatives with respect to space–time coordinates and second ordinary partial derivatives with respect to space–time coordinates — and the Lagrangian of the f(R) gravity. Interpreting the derived Hamiltonian as the energy of the f(R) gravity we have shown that it vanishes for linear Lagrangians in Ricci scalar curvature without source (e.g., Einstein–Hilbert Lagrangian without matter fields), which is the same result obtained using the stress–energy tensor equation derived from variation of the matter field Lagrangian density. The resulting Hamiltonian equation forbids any negative power law model in the dependence of the f(R) gravity on Ricci scalar curvature: f(R) = αR–r, where r and α are positive real numbers; it also forbids any polynomial equation that contains terms with negative powers of the Ricci scalar curvature including a constant term, in which cases the Hamiltonian function in the Ricci scalar and therefore the energy of the f(R) gravity would attain a negative value and would not be bounded from below. The restrictions imposed by the non-negative Hamiltonian have far-reaching consequences as a result of applying f(R) gravity to the study of black holes and the Friedmann–Lemaître–Robertson–Walker model in cosmology.
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Todorovic, Andreja, Branimir Grgur, and Jelena Rajovic. "Influence of current and temperature on discharge characteristics of electrochemical nickel−cadmium system." Chemical Industry 64, no. 4 (2010): 319–35. http://dx.doi.org/10.2298/hemind100214015t.
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The paper elaborates determination of characteristic values in the discharging process of non-hermetic nickel-cadmium galvanic battery with nominal voltage Un = 60 V and nominal capacity qn = C5 = 190 Ah and its dependence from current and temperature. Study has been performed with the set of experimental metering of voltages, electromotive force, current from discharge time range and electromotive force in steady state regime before and after battery charging. Electromotive force characteristics are obtained by using the Nernst?s equation, while the least square method was used to determine the average values of internal electrical resistivity, power losses and efficiency level. These results were used in the approximate exponential functions to determine the range dependence of the efficiency level from the internal electrical resistance of discharge current in reliance from the temperature range. Obtained results show that, in accordance to the given voltage variation of 10% Un, this type of battery holds maximal full load current of one hour capacity at the temperature of 25?C and maximal full load current of two hours capacity at the temperature of ?30?C. The methodology used in the case study covers determination of the electromotive force in time range based on the metered results of values during complete battery fullness and emptiness with prior determination of equilibrium constants of galvanic battery reaction through method suggested by the author of this paper. Further process, using the electromotive force values obtained through the aforementioned process, the metered current, and approximate polynomial function of the nominal discharge voltage characteristic determines range of battery internal electric resistance from time, followed by the selection of discharge cases with average values for: voltage, electromotive force, internal electrical resistance, available and utilized power, power losses, and battery efficiency level. An overview of the obtained characteristics for analyzed battery and their comparison with the producers prescribed values and standards led to gaining of the valuable data that show how and in what measure do current and temperature influence the discharge characteristic of non-hermetic nickel-cadmium batteries with an especial observation of internal electrical resistance and battery efficiency level. Obtained results show that electrochemical power sources may provide electric energy with prescribed quality and quantity, with high level of work reliability, as well as with all other positive technical and economic effects within the given current-temperature range.
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Kuhlmann, Marco. "Mildly Non-Projective Dependency Grammar." Computational Linguistics 39, no. 2 (June 2013): 355–87. http://dx.doi.org/10.1162/coli_a_00125.
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Syntactic representations based on word-to-word dependencies have a long-standing tradition in descriptive linguistics, and receive considerable interest in many applications. Nevertheless, dependency syntax has remained something of an island from a formal point of view. Moreover, most formalisms available for dependency grammar are restricted to projective analyses, and thus not able to support natural accounts of phenomena such as wh-movement and cross–serial dependencies. In this article we present a formalism for non-projective dependency grammar in the framework of linear context-free rewriting systems. A characteristic property of our formalism is a close correspondence between the non-projectivity of the dependency trees admitted by a grammar on the one hand, and the parsing complexity of the grammar on the other. We show that parsing with unrestricted grammars is intractable. We therefore study two constraints on non-projectivity, block-degree and well-nestedness. Jointly, these two constraints define a class of “mildly” non-projective dependency grammars that can be parsed in polynomial time. An evaluation on five dependency treebanks shows that these grammars have a good coverage of empirical data.
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Burmasheva, N. V., and E. Yu Prosviryakov. "Isothermal layered flows of a viscous incompressible fluid with spatial acceleration in the case of three Coriolis parameters." Diagnostics, Resource and Mechanics of materials and structures, no. 3 (May 2020): 29–46. http://dx.doi.org/10.17804/2410-9908.2020.3.029-046.
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We study the solvability of the overdetermined system of Navier–Stokes equations, supple-mented by the incompressibility equation, which is used to describe isothermal large-scale shear flows of a rotating viscous incompressible fluid. Large–scale flows are studied in a thin-layer ap-proximation (the vertical velocity of the fluid is assumed to be zero). The rotation of a continuous fluid medium is described by three Coriolis parameters. The solution of the reduced system of Na-vier–Stokes equations is constructed in the Lin–Sidorov–Aristov class. In this case, both nonzero components of the velocity vector, the pressure and temperature fields are assumed to be full linear forms of two Cartesian coordinates, and the dependence on the third Cartesian coordinate has an arbitrary form (including non-polynomial). It is shown that the nonlinear overdetermined system of Navier–Stokes equations and of the incompressibility equation in the framework of the Lin–Sidorov–Aristov class reduces to the equivalent nonlinear overdetermined system of ordinary dif-ferential equations, in which the components of the hydrodynamic fields act as unknown functions. The compatibility condition for the equations of the resulting system is derived. It is shown that, if this compatibility condition is fulfilled, the system has a unique solution, and the spatial accelera-tions in both variables (the linearity with respect to them was postulated when choosing the solution class) prove to be constant functions. These results are a generalization of similar results obtained earlier in the study of solvability in the cases of one and two Coriolis parameters.
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Titova, A. V., and V. I. Golik. "Prospects for Increasing Mineral Resource Base of Non-Ferrous Metals Industry." Mining Industry Journal (Gornay Promishlennost), no. 1/2021 (March 15, 2021): 61–68. http://dx.doi.org/10.30686/1609-9192-2021-1-61-68.
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The importance of research into enhancing the metal mining technologies is justified by the declining availability of mineral resources due to non-compliance of the conventional mining methods with the market conditions. The traditional ore processing technologies are accompanied by accumulation of processing tailings. Zero-waste recycling of primary processing waste, which is often used without extracting metals to match the sanitary standards, is not evolving. The acute environmental issues are primarily exacerbated by a lack of levers for centralized accounting and management of the accumulated waste. The aim of the study is to develop new technologies that are optimized in terms of complete utilization of the off-grade raw materials i.e. wastes from primary ore processing. The effectiveness of leaching technologies is proved with a complex method that involves experiments and calculations comparing the performance of processing options using the Box-Behnken design of metal extraction and interpreting the results in the form of logarithmic or polynomial interpolation. Quantitative values were obtained and cross-plots of metal extraction dependence on the contributing factors were made, which allow characterizing the leaching processes of polymetals and ferruginous quartzites in the disintegrator. It has been proved that mechanochemical treatment provides higher metal yield (up to 45%) than traditional waste processing technologies while securing a safety level that meets the sanitary requirements. It has also been determined that disintegrator activation during the metal leaching process increases the strength of concrete mixtures based on re-treated tailings, both as aggregates and as a binder. A conclusion is made that activation of the leaching processes in a disintegrator ensures the extraction of 50 to 80% of metals that are not available for extraction from mill tailing with conventional technologies. Development of man-made deposits using innovative technologies based on metal leaching is a real step towards expanding the mineral resource base of the metallurgical industry and improving the environmental situation in the mining regions. In contrast to technologies of a similar scope and purpose, the proposed technology makes it possible to process ores in a zero-waste manner without creating new tailings.
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Yu. Moshin, Pavel, and Alexander A. Reshetnyak. "Finite field-dependent BRST–anti-BRST transformations: Jacobians and application to the Standard Model." International Journal of Modern Physics A 31, no. 20n21 (July 27, 2016): 1650111. http://dx.doi.org/10.1142/s0217751x16501116.
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We continue our research[Formula: see text] and extend the class of finite BRST–anti-BRST transformations with odd-valued parameters [Formula: see text], [Formula: see text], introduced in these works. In doing so, we evaluate the Jacobians induced by finite BRST–anti-BRST transformations linear in functionally-dependent parameters, as well as those induced by finite BRST–anti-BRST transformations with arbitrary functional parameters. The calculations cover the cases of gauge theories with a closed algebra, dynamical systems with first-class constraints, and general gauge theories. The resulting Jacobians in the case of linearized transformations are different from those in the case of polynomial dependence on the parameters. Finite BRST–anti-BRST transformations with arbitrary parameters induce an extra contribution to the quantum action, which cannot be absorbed into a change of the gauge. These transformations include an extended case of functionally-dependent parameters that implies a modified compensation equation, which admits nontrivial solutions leading to a Jacobian equal to unity. Finite BRST–anti-BRST transformations with functionally-dependent parameters are applied to the Standard Model, and an explicit form of functionally-dependent parameters [Formula: see text] is obtained, providing the equivalence of path integrals in any 3-parameter [Formula: see text]-like gauges. The Gribov–Zwanziger theory is extended to the case of the Standard Model, and a form of the Gribov horizon functional is suggested in the Landau gauge, as well as in [Formula: see text]-like gauges, in a gauge-independent way using field-dependent BRST–anti-BRST transformations, and in [Formula: see text]-like gauges using transverse-like non-Abelian gauge fields.
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Javidian, Mohammad Ali, Marco Valtorta, and Pooyan Jamshidi. "AMP Chain Graphs: Minimal Separators and Structure Learning Algorithms." Journal of Artificial Intelligence Research 69 (October 7, 2020): 419–70. http://dx.doi.org/10.1613/jair.1.12101.
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This paper deals with chain graphs (CGs) under the Andersson–Madigan–Perlman (AMP) interpretation. We address the problem of finding a minimal separator in an AMP CG, namely, finding a set Z of nodes that separates a given non-adjacent pair of nodes such that no proper subset of Z separates that pair. We analyze several versions of this problem and offer polynomial time algorithms for each. These include finding a minimal separator from a restricted set of nodes, finding a minimal separator for two given disjoint sets, and testing whether a given separator is minimal. To address the problem of learning the structure of AMP CGs from data, we show that the PC-like algorithm is order dependent, in the sense that the output can depend on the order in which the variables are given. We propose several modifications of the PC-like algorithm that remove part or all of this order-dependence. We also extend the decomposition-based approach for learning Bayesian networks (BNs) to learn AMP CGs, which include BNs as a special case, under the faithfulness assumption. We prove the correctness of our extension using the minimal separator results. Using standard benchmarks and synthetically generated models and data in our experiments demonstrate the competitive performance of our decomposition-based method, called LCD-AMP, in comparison with the (modified versions of) PC-like algorithm. The LCD-AMP algorithm usually outperforms the PC-like algorithm, and our modifications of the PC-like algorithm learn structures that are more similar to the underlying ground truth graphs than the original PC-like algorithm, especially in high-dimensional settings. In particular, we empirically show that the results of both algorithms are more accurate and stabler when the sample size is reasonably large and the underlying graph is sparse
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Ezzeddine, R., T. Merle, B. Plez, M. Gebran, F. Thévenin, and M. Van der Swaelmen. "An empirical recipe for inelastic hydrogen-atom collisions in non-LTE calculations." Astronomy & Astrophysics 618 (October 2018): A141. http://dx.doi.org/10.1051/0004-6361/201630352.
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Context. Determination of high-precision abundances of late-type stars has been and always will be an important goal of spectroscopic studies, which requires accurate modeling of their stellar spectra with non-local thermodynamic equilibrium (NLTE) radiative transfer methods. This entails using up-to-date atomic data of the elements under study, which are still subject to large uncertainties.Aims. We investigate the role of hydrogen collisions in NLTE spectral line synthesis, and introduce a new general empirical recipe to determine inelastic charge transfer (CT) and bound-bound hydrogen collisional rates. This recipe is based on fitting the energy functional dependence of published quantum collisional rate coefficients of several neutral elements (BeI, Na I, Mg I, Al I, Si Iand Ca I) using simple polynomial equations.Methods. We perform thorough NLTE abundance calculation tests using our method for four different atoms, Na, Mg, Al and Si, for a broad range of stellar parameters. We then compare the results to calculations computed using the published quantum rates for all the corresponding elements. We also compare to results computed using excitation collisional rates via the commonly used Drawin equation for different fudge factors,SMH, applied.Results. We demonstrate that our proposed method is able to reproduce the NLTE abundance corrections performed with the quantum rates for different spectral types and metallicities for representative Na Iand Al Ilines to within ≤0.05 dex and ≤0.03 dex, respectively. For Mg Iand Si Ilines, the method performs better for the cool giants and dwarfs, while larger discrepancies up to 0.2 dex could be obtained for some lines for the subgiants and warm dwarfs. We obtained larger NLTE correction differences between models incorporating Drawin rates relative to the quantum models by up to 0.4 dex. These large discrepancies are potentially due to ignoring either or both CT and ionization collisional processes by hydrogen in our Drawin models.Conclusions. Our general empirical fitting method (EFM) for estimating hydrogen collision rates performs well in its ability to reproduce, within narrow uncertainties, the abundance corrections computed with models incorporating quantum collisional rates. It performs generally best for the cool and warm dwarfs, with slightly larger discrepancies obtained for the giants and subgiants. It could possibly be extended in the future to transitions of the same elements for which quantum calculations do not exist, or, in the absence of published quantum calculations, to other elements as well.
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Tilstra, Lieuwe G., Olaf N. E. Tuinder, Ping Wang, and Piet Stammes. "Directionally dependent Lambertian-equivalent reflectivity (DLER) of the Earth's surface measured by the GOME-2 satellite instruments." Atmospheric Measurement Techniques 14, no. 6 (June 8, 2021): 4219–38. http://dx.doi.org/10.5194/amt-14-4219-2021.
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Abstract. In this paper we introduce the new concept of directionally dependent Lambertian-equivalent reflectivity (DLER) of the Earth's surface retrieved from satellite observations. This surface DLER describes Lambertian (isotropic) surface reflection which is extended with a dependence on the satellite viewing geometry. We apply this concept to data of the GOME-2 satellite instruments to create a global database of the reflectivity of the Earth's surface, providing surface DLER for 26 wavelength bands between 328 and 772 nm as a function of the satellite viewing angle via a second-degree polynomial parameterisation. The resolution of the database grid is 0.25∘ by 0.25∘, but the real, intrinsic spatial resolution varies over the grid from 1.0∘ by 1.0∘ to 0.5∘ by 0.5∘ down to 0.25∘ by 0.25∘ by applying dynamic gridding techniques. The database is based on more than 10 years (2007–2018) of GOME-2 data from the MetOp-A and MetOp-B satellites. The relation between DLER and bi-directional reflectance distribution function (BRDF) surface reflectance is studied using radiative transfer simulations. For the shorter wavelengths (λ<500 nm), there are significant differences between the two. For instance, at 463 nm the difference can go up to 6 % at 30∘ solar zenith angle. The study also shows that, although DLER and BRDF surface reflectances have different properties, they are comparable for the longer wavelengths (λ>500 nm). Based on this outcome, the GOME-2 surface DLER is compared with MODIS surface BRDF data from MODIS band 1 (centred around 645 nm) using both case studies and global comparisons. The conclusion of this validation is that the GOME-2 DLER compares well to MODIS BRDF data and that it does so much better than the non-directional LER database. The DLER approach for describing surface reflectivity is therefore an important improvement over the standard isotropic (non-directional) LER approaches used in the past. The GOME-2 surface DLER database can be used for the retrieval of atmospheric properties from GOME-2 and from previous satellite instruments like GOME and SCIAMACHY. It will also be used to support retrievals from the future Sentinel-5 UVNS (ultraviolet, visible, near-infrared, and short-wave infrared) satellite instrument.
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Kirsanov, Mikhail N., and Dmitriy V. Tinkov. "ANALYTICAL SOLUTION OF THE FREQUENCY OF THE LOAD OSCILLATION AT AN ARBITRARY GIRDER NODE IN THE SYSTEM MAPLE." Stroitel stvo nauka i obrazovanie [Construction Science and Education], no. 4 (2019): 3. http://dx.doi.org/10.22227/2305-5502.2018.4.3.
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Introduction. We study the oscillations of a massive load on a planar statically definable symmetric truss of a regular type with parallel belts. Truss weight is not included. Free vertical oscillations are considered. The stiffness of the truss rods is assumed to be the same, the deformations are elastic. Lattice of the truss is double with descending braces and racks. New in the formulation and solution of the problem is the analytical form of the solution, which makes it possible in practice to easily evaluate the frequency characteristics of the structure depending on an arbitrary number of truss panels and the location of the load. Materials and methods. The operators and methods of the system of computer mathematics Maple are used. To determine the forces in the rods, the knotting method is used. The common terms of the sequence of coefficients of solutions for different numbers of panels are obtained from solving linear homogeneous recurrent equations of various order, obtained by special operators of the Maple system. Dependence on two arbitrary natural parameters is revealed in two stages. First, solutions for fixed load positions are found, then these solutions are summarized into one final formula for frequency. Results. By a series of individual solutions to the problem of load oscillation using the double induction method, it was possible to find common members of all sequences. The solution is polynomial in both natural parameters. Graphs constructed for particular cases, showed the adequacy of the approach. The discontinuous non-monotonic nature of the intermittent change depending on the number of truss panels and some other features of the solution are noted. Conclusions. It is shown that the induction method, previously applicable mainly to statics problems with one parameter (number of truss panels), is fully operational to the problems of the oscillations of system with two natural parameters. It should be noted that significant labor costs and a significant increase in the time symbolic transformations in such tasks
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Kaltayev, A., Ye Belyayev, and A. Naimanova. "2D-DNS and 2D-RANS Simulations of Supersonic QUASI-2D Turbulent Reacting Shear Flow." Eurasian Chemico-Technological Journal 16, no. 2-3 (April 8, 2014): 239. http://dx.doi.org/10.18321/ectj187.
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<p>Numerical studies of quasi-2D supersonic turbulent hydrogen-air mixing and combustion in free shear layer configuration are performed using 2D-DNS [1] and RANS equations. In order to produce the roll-up and pairing of vortex rings, an unsteady boundary condition is applied at the inlet plane. Frequencies of<br /> initial velocity perturbations have been taken in accordance with linear stability theory. The influences of different inflow perturbations on mixing layer structure are presented. At the outflow, the non-reflecting boundary condition is adopted. In the case of RANS simulation two-parameter k-e turbulence model is used. Thermal conduction is described by Fourier’s law, while diffusion of species by Fick’s law. Equation of state for thermally perfect multispecies gas is used. Thermodynamic parameters, such as specific heat, enthalpy, entropy and internal energy are determined by fourth order degree polynomial formula, which has dependence on temperature. Temperature is determined using Newton-Raphson iteration procedure. The Wilke’s formula is used to determine the mixture viscosity coefficient. Approximation of convection terms are performed by the ENO-scheme of third-order accuracy and approximation of diffusion terms – by second-order central-difference operators. For the description of reaction pathways of hydrogen, a seven species chemical reaction model by Jachimowski is adopted. Chemical reaction source term implicitly includes in mass fraction transport equations, where linearization is applied using Taylor decomposition. The hydrogen flow parameters are M<sub>0</sub> = 2.0, T<sub>0</sub> = 2000 K, P<sub>0</sub> = 101325 Pa, and air flow parameters are M<sub>¥</sub> = 2.1, T<sub>¥</sub> = 2000 K, p<sub>¥</sub> = 101325 Pa. Convective Mach number is M<sub>c</sub> = 0.38, where effect of compressibility is significant.</p>
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Gómez-Rodríguez, Carlos, John Carroll, and David Weir. "Dependency Parsing Schemata and Mildly Non-Projective Dependency Parsing." Computational Linguistics 37, no. 3 (September 2011): 541–86. http://dx.doi.org/10.1162/coli_a_00060.
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We introduce dependency parsing schemata, a formal framework based on Sikkel's parsing schemata for constituency parsers, which can be used to describe, analyze, and compare dependency parsing algorithms. We use this framework to describe several well-known projective and non-projective dependency parsers, build correctness proofs, and establish formal relationships between them. We then use the framework to define new polynomial-time parsing algorithms for various mildly non-projective dependency formalisms, including well-nested structures with their gap degree bounded by a constant k in time O(n5+2k), and a new class that includes all gap degree k structures present in several natural language treebanks (which we call mildly ill-nested structures for gap degree k) in time O(n4+3k). Finally, we illustrate how the parsing schema framework can be applied to Link Grammar, a dependency-related formalism.
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Arola, Antti, William Wandji Nyamsi, Antti Lipponen, Stelios Kazadzis, Nickolay A. Krotkov, and Johanna Tamminen. "Rethinking the correction for absorbing aerosols in the OMI- and TROPOMI-like surface UV algorithms." Atmospheric Measurement Techniques 14, no. 7 (July 15, 2021): 4947–57. http://dx.doi.org/10.5194/amt-14-4947-2021.
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Abstract. Satellite estimates of surface UV irradiance have been available since 1978 from the TOMS UV spectrometer and have continued with significantly improved ground resolution using the Ozone Monitoring Instrument (OMI 2004–current) and Sentinel 5 Precursor (S5P 2017–current). The surface UV retrieval algorithm remains essentially the same: it first estimates the clear-sky UV irradiance based on measured ozone and then accounts for the attenuation by clouds and aerosols, applying two consecutive correction factors. When estimating the total aerosol effect in surface UV irradiance, there are two major classes of aerosols to be considered: (1) aerosols that only scatter UV radiation and (2) aerosols that both scatter and absorb UV radiation. The former effect is implicitly included in the measured effective Lambertian-equivalent scene reflectivity (LER), so the scattering aerosol influence is estimated through cloud correction factor. Aerosols that absorb UV radiation attenuate the surface UV radiation more strongly than non-absorbing aerosols of the same extinction optical depth. Moreover, since these aerosols also attenuate the outgoing satellite-measured radiance, the cloud correction factor that treats these aerosols as purely scattering underestimates their aerosol optical depth (AOD), causing underestimation of LER and overestimation of surface UV irradiance. Therefore, for correction of aerosol absorption, additional information is needed, such as a model-based monthly climatology of aerosol absorption optical depth (AAOD). A correction for absorbing aerosols was proposed almost a decade ago and later implemented in the operational OMI and TROPOMI UV algorithms. In this study, however, we show that there is still room for improvement to better account for the solar zenith angle (SZA) dependence and nonlinearity in the absorbing aerosol attenuation, and as a result we propose an improved correction scheme. There are two main differences between the new proposed correction and the one that is currently operational in OMI and TROPOMI UV algorithms. First, the currently operational correction for absorbing aerosols is a function of AAOD only, while the new correction additionally takes the solar zenith angle dependence into account. Second, the second-order polynomial of the new correction takes the nonlinearity in the correction as a function of AAOD better into account, if compared to the currently operational one, and thus better describes the effect by absorbing aerosols over a larger range of AAOD. To illustrate the potential impact of the new correction in the global UV estimates, we applied the current and new proposed correction for global fields of AAOD from the aerosol climatology currently used in OMI UV algorithm, showing a typical differences of ±5 %. This new correction is easy to implement operationally using information of solar zenith angle and existing AAOD climatology.
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Virbule, Inese, Dmitrijs Serdjuks, and Karina Buka-Vaivade. "BEHAVIOUR'S ANALYSIS OF LOAD-CARRYING MEMBERS FOR TIMBER FRAMEWORK BUILDING." ENVIRONMENT. TECHNOLOGIES. RESOURCES. Proceedings of the International Scientific and Practical Conference 1 (June 20, 2019): 330. http://dx.doi.org/10.17770/etr2019vol1.4068.
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The problem of limited raw material and energy resources can be solved by the replacement of non-renewable structural materials by renewable ones. Using of timber structures enables to decrease impact on the planet. It will also help to reverse some of the effects of industrialization. Structural members from solid and glued laminated timber, cross-laminated timber and other timber-based materials are widely used for one-storey and multi-storey buildings. Three-storey timber framework building was considered as an object of investigations. The considered three-storey building has length and width equal to 28 and 13 m, correspondingly. The using of software Autodesk Robot Structural developed FEM model of three-storey platfom framed framework building. Load-carrying structures of considered framework building consist from the load-carrying walls, floors and roofs structures, which develop horizontal and vertical diaphragms providing strength and rigidity of the framework. The rational bay of the light framework structures changes within the limits from 300 to 600 mm. The rational span of beams and purlins does not exceed 4 m. Solid timber with the strength class C24 was assumed as a structural material for timber frameworks members. The OSB sheets were considered as a material of the cladding for external structures. Behaviour of the load-carrying shear walls were analysed by the using of FEM models developed by the software Autodesk Robot Structural and ANSYS 15 so as methods explained in EN 1995-1-1. The software ANSYS 15 was used for the development of separate model of load-carrying shear walls. Initial unit of shear wall – a panel with the dimensions 1.2X2.7 m was considered for the purpose. The bar sub-members of the panel were modelled by the BEAM 188 finite element type. The SHELL 181 and COMBIN 14 finite element types modelled the cladding sub-members and mechanical fasteners. The dependence between the horizontal displacements of the load-carrying wall, intensity of the applied load, area of the openings so as thickness of the wall was obtained as a second power polynomial equation. It was stated, that the obtained FEM models enables to describe the behaviours of the load-carrying shear walls with enough precision.
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Mazer, Norman Alan, Tomas Tomka, Michael Winter, Annette Koerner, and Samir K. Ballas. "Re-Assessing the Red Blood Cell Lifespan in Sickle Cell Anemia: Does Size Matter?" Blood 132, Supplement 1 (November 29, 2018): 4877. http://dx.doi.org/10.1182/blood-2018-99-110592.
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Abstract Background: Does the size of RBCs in sickle cell anemia (SCA) influence their lifespan? According to Ballas and Marcolina's study of 26 SCA patients (Hemoglobin 2000), the half-life of 51Cr labelled RBCs (T1/2) had a statistically significant negative correlation with MCV (p = 0.009), that was described by the regression equation: T1/2 (days) = 9.3 - 0.22 x [MCV (fL) - 87]. We have used this equation to derive a quantitative relationship between the RBC lifespan (LSRBC) and RBC size (MCV) and have tested this relationship with the data of Higgs et al. (N Engl J Med 1982) in SCA patients with and without concomitant α-thalassemia. We also reassessed the RBC survival kinetics of non-F-cells in 12 SCA patients (Franco et al. Blood 2006) to explore a size effect. A mechanistic hypothesis for a causal relationship between RBC size and LSRBC is proposed. Methods: The numerical relationship between LSRBC and T1/2 was derived using Engstedt's theoretical model (Acta Med Scand. Suppl. 1957) for the case of auto-transfusion in patients with hemolytic anemia. Combining this relationship with the experimental regression equation of T1/2 vs. MCV yielded a prediction of the dependence of LSRBC vs. MCV, which was accurately represented by a 2nd degree polynomial. This dependence was used to estimate the LSRBC values corresponding to the 3 groups of SCA patients studied by Higgs et al. (N Engl J Med 1982), whose mean MCV values were 90.1 fL (4 α-globin genes), 84.4 fL (3 α-globin genes) and 71.2 fL (2 α-globin genes). For comparison, we estimated LSRBC values for patients with 4 and 2 α-globin genes directly from the T1/2 values reported by De Ceulaer et al. (N Engl J Med 1983). An indirect estimate of LSRBC was derived from the ratio of the reticulocyte lifespan to the % reticulocytes reported in the 3 groups, with the former parameter set to 1.82 days in order to match the LSRBC prediction of the 4 α-globin gene group. A further estimate was derived from the levels of total bilirubin, Hb and MCHC using a theoretical expression that was also adjusted to match the 4 α-globin gene prediction. From the data on RBC survival kinetics in SCA patients reported by Franco et al. (Blood 2006), we estimated the T50% survival times of non-F-cells and explored their relationship to MCV. Results: The dependence of LSRBC vs. MCV derived from Ballas and Marcolina's data (Hemoglobin 2000) shows a marked decrease from 25 days to 10 days as MCV increases from 73 to 101 fL (Figure 1). Using this relationship, a corresponding increase in the predicted LSRBC values is shown for the SCA patients of Higgs et al. (N Engl J Med 1982) with α-gene numbers corresponding to 4 (no α-thalassemia), 3 (heterozygous α-thalassemia) and 2 (homozygous α-thalassemia), respectively (Figure 2). The estimated LSRBC values derived from the data of De Ceulaer et al. (N Engl J Med 1983) in patients with 4 and 2 α-globin genes are in good agreement with our predictions (Figure 2). Indirect estimates of LSRBC, based on the % reticulocytes and total bilirubin levels reported by of Higgs et al. and adjusted to match the 4 α-globin gene group, are also in good agreement with the predicted LSRBC values for the 3 and 2 α-globin gene groups (Figure 2). Lastly the T50% survival times for non-F-cells derived from Franco et al. (Blood 2006) are seen to be inversely related to the MCV with a variation of about 3-fold (Figure 3). Discussion: Our reassessment of literature data in SCA patients illustrates a strong inverse relationship between the RBC lifespan and RBC size (MCV). The confounding of this finding by the presence of hetero- and homozygous α-thalassemia in the lower MCV groups cannot be excluded, nor can the influence of the MCHC, which varies weakly with MCV. Nonetheless, we suggest that this relationship could result from the following causal mechanism. Smaller RBCs (initially in the oxygenated state) should have a shorter capillary transit time than larger RBCs, as seen in theoretical simulations (Secomb and Hsu, Biophysical journal. 1996) and experimental studies (Du et al. PNAS 2015). A shorter transit time should limit the time for deoxygenation and HbS polymerization; leading to less sickling, less cell damage and less hemolysis. The reduced rate of hemolysis should result in a longer RBC lifespan. Our quantitative analysis and causal hypothesis suggest that size matters in the lifespan of sickle cells. The clinical and therapeutic implications of this hypothesis require further consideration. Disclosures Mazer: F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Tomka:Roche: Employment. Winter:Roche: Employment. Koerner:F. Hoffmann-La Roche Ltd: Employment.
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Helmi, B. Hoda, Adel T. Rahmani, and Martin Pelikan. "A factor graph based genetic algorithm." International Journal of Applied Mathematics and Computer Science 24, no. 3 (September 1, 2014): 621–33. http://dx.doi.org/10.2478/amcs-2014-0045.
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Abstract We propose a new linkage learning genetic algorithm called the Factor Graph based Genetic Algorithm (FGGA). In the FGGA, a factor graph is used to encode the underlying dependencies between variables of the problem. In order to learn the factor graph from a population of potential solutions, a symmetric non-negative matrix factorization is employed to factorize the matrix of pair-wise dependencies. To show the performance of the FGGA, encouraging experimental results on different separable problems are provided as support for the mathematical analysis of the approach. The experiments show that FGGA is capable of learning linkages and solving the optimization problems in polynomial time with a polynomial number of evaluations.
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WEBB, G. M., A. R. ZAKHARIAN, M. BRIO, and G. P. ZANK. "Parametric instabilities and wave coupling in Alfvén simple waves." Journal of Plasma Physics 66, no. 3 (September 2001): 167–212. http://dx.doi.org/10.1017/s0022377801001283.
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A wave coupling formalism for magnetohydrodynamic (MHD) waves in a non-uniform background flow is used to study parametric instabilities of the large-amplitude, circularly polarized, simple plane Alfvén wave in one Cartesian space dimension. The large-amplitude Alfvén wave (the pump wave) is regarded as the background flow, and the seven small-amplitude MHD waves (the backward and forward fast and slow magnetoacoustic waves, the backward and forward Alfvén waves, and the entropy wave) interact with the pump wave via wave coupling coefficients that depend on the gradients and time dependence of the background flow. The dispersion equation for the waves D(k,ω) = 0 obtained from the wave coupling equations reduces to that obtained by previous authors. The general solution of the initial value problem for the waves is obtained by Fourier and Laplace transforms. The dispersion function D(k,ω) is a fifth-order polynomial in both the wavenumber k and the frequency ω. The regions of instability and the neutral stability curves are determined. Instabilities that arise from solving the dispersion equation D(k,ω) = 0, both in the form ω = ω(k), where k is real, and in the form k = k(ω), where ω is real, are investigated. The instabilities depend parametrically on the pump wave amplitude and on the plasma beta. The wave interaction equations are also studied from the perspective of a single master wave equation, with multiple wave modes, and with a source term due to the entropy wave. The wave hierarchies for short- and long-wavelength waves of the master wave equation are used to discuss wave stability. Expanding the dispersion equation for the different long-wavelength eigenmodes about k = 0 yields either the linearized Korteweg–deVries equation or the Schrödinger equation as the generic wave equation at long-wavelengths. The corresponding short-wavelength wave equations are also obtained. Initial value problems for the wave interaction equations are investigated. An inspection of the double-root solutions of the dispersion equation for k, satisfying the equations D(k,ω) = 0 and ∂D(k,ω) = ∂k = 0 and pinch point analysis shows that the solutions of the wave interaction equations for hump or pulse-like initial data develop an absolute instability. Fourier solutions and asymptotic analysis are used to study the absolute instability.
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Wang, Yang, Steffen Beirle, Francois Hendrick, Andreas Hilboll, Junli Jin, Aleksandra A. Kyuberis, Johannes Lampel, et al. "MAX-DOAS measurements of HONO slant column densities during the MAD-CAT campaign: inter-comparison, sensitivity studies on spectral analysis settings, and error budget." Atmospheric Measurement Techniques 10, no. 10 (October 12, 2017): 3719–42. http://dx.doi.org/10.5194/amt-10-3719-2017.
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Abstract. In order to promote the development of the passive DOAS technique the Multi Axis DOAS – Comparison campaign for Aerosols and Trace gases (MAD-CAT) was held at the Max Planck Institute for Chemistry in Mainz, Germany, from June to October 2013. Here, we systematically compare the differential slant column densities (dSCDs) of nitrous acid (HONO) derived from measurements of seven different instruments. We also compare the tropospheric difference of SCDs (delta SCD) of HONO, namely the difference of the SCDs for the non-zenith observations and the zenith observation of the same elevation sequence. Different research groups analysed the spectra from their own instruments using their individual fit software. All the fit errors of HONO dSCDs from the instruments with cooled large-size detectors are mostly in the range of 0.1 to 0.3 × 1015 molecules cm−2 for an integration time of 1 min. The fit error for the mini MAX-DOAS is around 0.7 × 1015 molecules cm−2. Although the HONO delta SCDs are normally smaller than 6 × 1015 molecules cm−2, consistent time series of HONO delta SCDs are retrieved from the measurements of different instruments. Both fits with a sequential Fraunhofer reference spectrum (FRS) and a daily noon FRS lead to similar consistency. Apart from the mini-MAX-DOAS, the systematic absolute differences of HONO delta SCDs between the instruments are smaller than 0.63 × 1015 molecules cm−2. The correlation coefficients are higher than 0.7 and the slopes of linear regressions deviate from unity by less than 16 % for the elevation angle of 1°. The correlations decrease with an increase in elevation angle. All the participants also analysed synthetic spectra using the same baseline DOAS settings to evaluate the systematic errors of HONO results from their respective fit programs. In general the errors are smaller than 0.3 × 1015 molecules cm−2, which is about half of the systematic difference between the real measurements.The differences of HONO delta SCDs retrieved in the selected three spectral ranges 335–361, 335–373 and 335–390 nm are considerable (up to 0.57 × 1015 molecules cm−2) for both real measurements and synthetic spectra. We performed sensitivity studies to quantify the dominant systematic error sources and to find a recommended DOAS setting in the three spectral ranges. The results show that water vapour absorption, temperature and wavelength dependence of O4 absorption, temperature dependence of Ring spectrum, and polynomial and intensity offset correction all together dominate the systematic errors. We recommend a fit range of 335–373 nm for HONO retrievals. In such fit range the overall systematic uncertainty is about 0.87 × 1015 molecules cm−2, much smaller than those in the other two ranges. The typical random uncertainty is estimated to be about 0.16 × 1015 molecules cm−2, which is only 25 % of the total systematic uncertainty for most of the instruments in the MAD-CAT campaign. In summary for most of the MAX-DOAS instruments for elevation angle below 5°, half daytime measurements (usually in the morning) of HONO delta SCD can be over the detection limit of 0.2 × 1015 molecules cm−2 with an uncertainty of ∼ 0.9 × 1015 molecules cm−2.
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Li, Zuchao, Hai Zhao, and Kevin Parnow. "Global Greedy Dependency Parsing." Proceedings of the AAAI Conference on Artificial Intelligence 34, no. 05 (April 3, 2020): 8319–26. http://dx.doi.org/10.1609/aaai.v34i05.6348.
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Most syntactic dependency parsing models may fall into one of two categories: transition- and graph-based models. The former models enjoy high inference efficiency with linear time complexity, but they rely on the stacking or re-ranking of partially-built parse trees to build a complete parse tree and are stuck with slower training for the necessity of dynamic oracle training. The latter, graph-based models, may boast better performance but are unfortunately marred by polynomial time inference. In this paper, we propose a novel parsing order objective, resulting in a novel dependency parsing model capable of both global (in sentence scope) feature extraction as in graph models and linear time inference as in transitional models. The proposed global greedy parser only uses two arc-building actions, left and right arcs, for projective parsing. When equipped with two extra non-projective arc-building actions, the proposed parser may also smoothly support non-projective parsing. Using multiple benchmark treebanks, including the Penn Treebank (PTB), the CoNLL-X treebanks, and the Universal Dependency Treebanks, we evaluate our parser and demonstrate that the proposed novel parser achieves good performance with faster training and decoding.