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Tytuł:
Tolerance Analysis with Multiple Surrogate Models
Autorzy:
Bayram, U.
Acar, E.
Powiązania:
https://bibliotekanauki.pl/articles/1402505.pdf
Data publikacji:
2015-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.70.-c
Opis:
Design and analysis of modern engineering systems are complicated, mostly relying on computational analyses codes and hence often computationally expensive. Meanwhile, improved computer-aided design and numerical simulation methods are used extensively in the design process. Even continuing growth of computing power and speed, computationally cheap and reliable models or simulation techniques are not available, at least as ready-to-use computer analysis codes. The necessity of tolerance analysis takes important place at the same time with improved CAD and computer based process planning, because of high quality production requirements, and reduces manufacturing costs. Simulation based design and optimization becomes the only option to meet the specifications, and improves the system reliability. In the last few decades, the use of surrogate models has achieved significant advantages, because they provide fast computation and design investigation as they replace computationally expensive to run computer analyses with cheap to run approximations. Surrogate models also simplify the integration of analyses codes to optimization and reliability assessment studies. In this paper, response surface and Kriging surrogate models are used within a Monte Carlo simulation framework for tolerance analysis. As an illustrative example problem, tolerance analyses of a clutch assembly with nonlinear objection function are used. The effects of the surrogate model parameters (e.g., the use of different regression polynomials) and the number of training points on tolerance analysis are explored.
Źródło:
Acta Physica Polonica A; 2015, 128, 2B; B-447-B-449
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vibrating Subsystems of Freight Wagons and Their Beam Models
Autorzy:
Buchacz, A.
Powiązania:
https://bibliotekanauki.pl/articles/1032555.pdf
Data publikacji:
2017-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.-t
Opis:
The application of analysis of transverse vibrating subsystem of complex microelectromechanical systems by means of the exact and approximate methods were the main purposes of work to solve the task of assignment of frequency-modal analysis and characteristics of mechatronic system. The problems concerned of piezoelectricity and electrostriction and classical and nonclassical methods to solve this problem have been used to obtain the dynamical characteristics in the Gliwice Research Centre. Other diverse problems have been modeled by different methods and next they were examined and analysed. Analysing the diagrams of characteristics of confirmed system, it has been determined that in case of approximate method the resonance frequencies cover with those which have been determined with the exact method. However the values of the characteristic in other areas were different. The main aim of this paper is to compare the transients of characteristics of mechanical subsystem of the transverse vibrating discrete - continuous mechatronic system, obtained by the exact and the approximate Galerkin method and to answer the question - if the method can be used to nominate the characteristics of mechatronic systems. The main subject of deliberation was to determine the flexibility of the mechanical system with constant cross-section using the exact and the Galerkin method. The problems presented in this paper, that means the analysis of subsystem of mechatronic and mechanical complex systems, is however the introduction to the synthesis of transverse vibrating mechatronic systems with assumed frequency spectrum.
Źródło:
Acta Physica Polonica A; 2017, 131, 1; 62-63
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kinetic Models of Epitaxial Growth: Theory and Experiment
Autorzy:
Vvedensky, D. D.
Smilauer, P.
Powiązania:
https://bibliotekanauki.pl/articles/1931853.pdf
Data publikacji:
1995-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.50.Cj
Opis:
We examine the morphological evolution of growing surfaces using Monte Carlo simulations of a solid-on-solid model. We use direct comparisons with experiment both to identify the kinetic processes that must be included in a model for GaAs(001) homoepitaxy and to parametrize the rates of these processes. We first examine the evolution of a vicinal surface during the first few monolayers of growth and compare the density of surface steps of the simulated surfaces with reflection high-energy electron-diffraction measurements. By including both a non-thermal incorporation step of freshly deposited atoms and a barrier to interlayer atomic transport, excellent quantitative agreement is obtained for an entire range of growth conditions, including the relaxation of the surface toward equilibrium upon the termination of the beam. We then examine the morphology as successively more layers are grown and find that the surface evolves into a self-organized state wherein the local slope of the growing features remains approximately constant with time.
Źródło:
Acta Physica Polonica A; 1995, 87, 1; 25-33
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Comparison of Different Theoretical Models of Positron Lifetime Spectra for Polymers
Autorzy:
Kansy, J.
Powiązania:
https://bibliotekanauki.pl/articles/1812531.pdf
Data publikacji:
2008-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
Opis:
The same reference positron lifetime spectra of polyurethane, measured in temperature range 112 to 390 K, were analyzed with three theoretical models: the "conventional" model with three exponential decay component of discrete values of lifetimes, a model with one discrete exponential component and two "packages" of exponentials with log-normal distribution of annihilation rates, and a model considering positronium slow localization, positronium internal relaxation as well as "delayed" formation of positronium. It turns out that the two latter models fit to the experimental data with the same excellent quality, in spite of the fact that in both models the ratio of intensities related to para-positronium and ortho-positronium was constrained to be as 1:3.
Źródło:
Acta Physica Polonica A; 2008, 113, 5; 1397-1407
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Field Theoretic Models of the Dispersive Dielectric Medium
Autorzy:
Artyszuk, Ź.
Bechler, A.
Powiązania:
https://bibliotekanauki.pl/articles/2035706.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.65.-k
12.20.-m
Opis:
The purpose of this paper is a description of the dispersive dielectric medium, both linear and nonlinear, from first principles using the field theoretic methods based on the Feynman path integrals over classical trajectories. The main idea is to use notion of effective fields, in the present case the electromagnetic field modified by presence of a polarizable medium. Interaction of the field with the medium on the microscopic level is described by a modified Hopfield Lagrangian containing terms corresponding to the electromagnetic field, the matter polarization field modelled by harmonic oscillators with some resonance frequency and other matter fields describing the degrees of freedom responsible for absorption in the medium (reservoir fields). The polarization field is coupled both to the electric field and the reservoir fields. Effective theory is obtained by elimination of the matter degrees of freedom which is achieved by functional integration over all matter fields. For a linear medium all calculations can be done exactly leading to the effective Lagrangian from which, among others, an expression for frequency dependent dielectric constant can be extracted. Explicit form of the dielectric constant depends on the way by which the polarization field couples to the reservoir fields. In particular, uniform coupling to all reservoir modes gives the standard Lorentz oscillator model, and for any type of coupling the Lorentz form of dielectric constant is retrieved for frequencies close to the resonance. For weak damping the dispersion ω(k) is little sensitive to the form of coupling leading to polariton modes not different from those of the Lorentz model. It is also outlined briefly how the functional integration method could be used to description of nonlinear effects in the medium.
Źródło:
Acta Physica Polonica A; 2003, 103, 2-3; 263-273
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diagnostic Inferring on the Bases of Nonlinear Models
Autorzy:
Dąbrowski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1537405.pdf
Data publikacji:
2010-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.40.Ga
45.80.+r
46.40.Ff
Opis:
Physical phenomena accompanying destruction processes of technical systems are nonlinear and "low-energetic" by nature, while during wearing out mainly a nonlinear disturbance changes. Out of many inference techniques - on the observation basis of the state of the system - the best one is undoubtedly the well-defined mathematical model, allowing inferring `backwards' and `forward', which means finding the genesis and prognosis of the phenomenon. However, such model should be nonlinear. Problems related to the identification of nonlinear dynamic models in a frequency domain and a proposition of solving this problem for the needs of technical diagnostics, i.e. in situations when the observed wear out effects are significantly smaller than the dynamic effects - are discussed in the hereby paper. The bases of the proposed method constitute the discussion of possible solutions of a certain class of nonlinear differential equations and resulting from that statements on the possibility of nonlinear disturbance approximations by a series of the selected harmonic frequencies.
Źródło:
Acta Physica Polonica A; 2010, 118, 1; 45-48
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Models of Personal Incomes in USA
Autorzy:
Łukasiewicz, P.
Karpio, K.
Orłowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1409048.pdf
Data publikacji:
2012-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.65.-s
89.65.Cd
Opis:
The shapes of distributions of personal incomes in USA have been investigated based on the data for 1993 to 2008. Comparisons between four models utilizing various number of parameters have been performed. The studies showed that the empirical data is described the best by the three-parameter Dagum model. Values of the models parameters indicate that the distribution of personal incomes can be regarded as zero-modal one. However, one-parameter exponential model shows a good agreement with data and can be treated as a good approximation of empirical distribution with the exception of the region with very high incomes. The high-income region is characterized by the relatively great number of events and is described much better by the Dagum distribution.
Źródło:
Acta Physica Polonica A; 2012, 121, 2B; B-82-B-85
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kondo Lattice Models for Rare-Earth and Actinide Systems
Autorzy:
Coqblin, B.
Powiązania:
https://bibliotekanauki.pl/articles/1426694.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.27.+a
75.10.Nr
75.30.Nr
Opis:
We present here some works on the strong competition between the Kondo effect, magnetic order and eventually spin glass or frustration effect in anomalous rare-earth and actinide systems. First, we develop an underscreened Kondo lattice model with $S_{f}$ = 1 spins for the 5f-electrons and we have recently improved it by deriving, by the Schrieffer-Wolff transformation, a 5f-band with a finite bandwidth. The underscreened Kondo lattice model can account for properties of some uranium and neptunium compounds, like UTe, $Np_2PdGa_3$ or $UCu_2Si_2$ which have a large Curie temperature $T_{c}$ of order 100 K and present also a Kondo behavior. In particular, we can account for the observed maximum of $T_{c}$ under pressure in UTe and the magnetization curves of $NpNiSi_2$ showing the occurrence of the Kondo effect at low temperatures below $T_{c}$. Second, we have studied the properties of disordered cerium alloys like $CeCu_xNi_{1-x}$ or $CeRh_xPd_{1-x}$ by considering the Kondo effect, a ferromagnetic order and a spin glass behavior described by several approaches. The van Hemmen approach gives a good explanation of the properties of cerium alloys and we are describing the magnetic glass clusters which occur in both spin glass and ferromagnetic phases. Third, we present a new description of a frustrated Kondo lattice model, which can account for the behavior under pressure or doping of some ytterbium compounds like $Yb_2Pd_2Sn$ and YbAgGe.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1005-1013
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pseudospin Models of Superconductors with Very Short Coherence Length
Autorzy:
Robaszkiewicz, S.
Powiązania:
https://bibliotekanauki.pl/articles/1860991.pdf
Data publikacji:
1994-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.20.-z
05.30.Jp
71.28.+d
Opis:
We discuss a few models developed for description of superconductivity with very short coherence length and point out their formal equivalence to specific spin models, such as an anisotropic Heisenberg model (s = 1/2) with two- and four-spin exchange coupling and with fixed magnetization in the z-direction, an XY-Z model with single ion anisotropy and a Kondo-lattice model with anisotropic on-site exchange. New results concerning the phase diagram of the Hubbard model with strong attraction, the electromagnetic properties of systems with the first order superconducting transition and a possibility of local charge moment compensation in systems of coexisting bound pairs and itinerant electrons are presented.
Źródło:
Acta Physica Polonica A; 1994, 85, 1; 117-131
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Construction of Equivalent Models of Continuous and Discrete-Continuous Systems
Autorzy:
Kasprzyk, S.
Marczuk, R.
Powiązania:
https://bibliotekanauki.pl/articles/1490367.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
46.70.De
46.40.-f
Opis:
New models have been constructed for three physical systems. These models are characterized by a uniform and transparent mathematical description. The mathematical description belongs to the class of generalized functions, which means that all equations as well as their solutions are understood in the sense of weak topology. The elements of the set of generalized functions need not be differentiable (in the classical sense) at each point domain of the function. Analyzing of actual systems in the class of generalized functions does not require a division into subsystems, which simplifies significantly execution of all mathematical operations. As compared with the classical methods, those presented in the study allow for a much faster achievement of the goal.
Źródło:
Acta Physica Polonica A; 2012, 121, 1A; A-191-A-196
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tight-Binding Models in a Quasiperiodic Optical Lattice
Autorzy:
Jagannathan, A.
Duneau, M.
Powiązania:
https://bibliotekanauki.pl/articles/1203062.pdf
Data publikacji:
2014-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.44.Br
67.85.-d
71.10.Fd
Opis:
This paper describes how one can use four standing wave laser fields to realize a two dimensional optical quasicrystal with eight-fold symmetry, closely related to the well-known octagonal or Ammann-Beenker tiling quasicrystal. We describe the structure and we outline the main features of an effective tight-binding model for atoms in this optical quasicrystal. Such a system, if realized experimentally, should provide valuable insights into the quantum properties of quasicrystals.
Źródło:
Acta Physica Polonica A; 2014, 126, 2; 490-492
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tests of the Structure-Based Models of Proteins
Autorzy:
Cieplak, M.
Sułkowska, J.
Powiązania:
https://bibliotekanauki.pl/articles/1808305.pdf
Data publikacji:
2009-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.80.Nj
87.15.ap
87.14.E-
Opis:
The structure-based models of proteins are defined through the condition that their ground state coincides with the native structure of the proteins. There are many variants of such models and they yield different properties. Optimal variants can be selected by making comparisons to experimental data on single-molecule stretching. Here, we discuss the 15 best performing variants and focus on fine tuning the selection process by adjusting the velocity of stretching to match the experimental conditions. The very best variant is found to correspond to the 10-12 potential in the native contacts with the energies modulated by the Miyazawa-Jernigan statistical potential and variable length parameters. The second best model incorporates the Lennard-Jones potential with uniform amplitudes. We then make a detailed comparison of the two models in which theoretical surveys of stretching properties of 7510 proteins were made previously.
Źródło:
Acta Physica Polonica A; 2009, 115, 2; 441-445
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
System Size Dependence of Entanglement in Quantum One-Dimensional Models
Autorzy:
Jakubczyk, D.
Jakubczyk, P.
Powiązania:
https://bibliotekanauki.pl/articles/1032462.pdf
Data publikacji:
2017-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
03.67.Bg
03.67.Lx
03.65.Ud
Opis:
We show that entanglement in one-dimensional spin and electron systems, with one excitation, depends only on the system size and has very simple form in both multipartite and bipartite case. Regarding the multipartite case, we present very simple expressions for global entanglement and N-concurrence, and show that they are mutually related. In the bipartite case, we give expressions for I-concurrence and negativity, and show that they are also dependent on each other.
Źródło:
Acta Physica Polonica A; 2017, 132, 1; 158-160
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Models for the Analysis of~IR Reflectivity in $TlBiTe_2$ with Different Size of Twins
Autorzy:
Hatzikraniotis, E.
Powiązania:
https://bibliotekanauki.pl/articles/1491508.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.Bh
78.30.-j
Opis:
In this work $TlBiTe_2$ were grown by a modified Bridgman technique and examined samples had different lateral dimensions of twins, ranging from 0.1 μm to 1 μm. The average lateral size of the twins seems to affect free carrier concentration and plasma frequency. Infrared spectra were analyzed by two models, the extended Drude model and a generalized empirical model of frequency-dependent damping factor. Increase in size of twins affects the electronic properties and hence plasma reflectivity and free carrier concentration of $TlBiTe_2$.
Źródło:
Acta Physica Polonica A; 2012, 121, 1; 284-286
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Frustration and Entanglement in Compass and Spin-Orbital Models
Autorzy:
Oleś, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/1384027.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Jm
64.70.Tg
75.25.Dk
79.60.-i
Opis:
We review the consequences of intrinsic frustration of the orbital superexchange and of spin-orbital entanglement. While the Heisenberg perturbing interactions remove frustration in the compass model, the lowest columnar excitations are robust in the nanoscopic compass clusters and might be used for quantum computations. Entangled spin-orbital states determine the ground states in some cases, while in others concern excited states and lead to measurable consequences, as in the RVO₃ perovskites. On-site entanglement for strong spin-orbit coupling generates the frustrated Kitaev-Heisenberg model with a rich magnetic phase diagram on the honeycomb lattice. Frustration is here reflected in hole propagation which changes from coherent in an antiferromagnet via hidden quasiparticles in zigzag and stripe phases to entirely incoherent one in the Kitaev spin liquid.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 163-169
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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