This paper deals with the atom energy mean value of the platinum nanoparticles of various size (from 300 to 3000 atoms that approximately corresponds to the transition threshold from the icosahedral structure to the f...
详细信息
ISBN:
(纸本)9781510809888
This paper deals with the atom energy mean value of the platinum nanoparticles of various size (from 300 to 3000 atoms that approximately corresponds to the transition threshold from the icosahedral structure to the face-centered cubic one) on the face-centered cubic lattice and on the five-fold symmetry one, with the application of the modified metropolis algorithm based on the Monte-Carlo method. When calculating the energy the quantum Sutton-Chen potential is used. (C) 2015 The Authors. Published by Elsevier Ltd.
Aiming at the large bias of LSE (Least Squares Estimation) in estimating MTBF (mean time between failures) under a small sample of data, a Bayesian MTBF estimating method is proposed for NC (numerical control) machine...
详细信息
ISBN:
(纸本)9781467391665
Aiming at the large bias of LSE (Least Squares Estimation) in estimating MTBF (mean time between failures) under a small sample of data, a Bayesian MTBF estimating method is proposed for NC (numerical control) machine tools. To solve difficulty in directly presenting the prior distributions of Weibull parameters, an expert-judgment method which incorporates prior information is developed to indirectly obtain Weibull parameters' prior distributions. Aiming at the problem that analytic solutions to Weibull parameters' posterior distributions and estimators are impossible to obtain, a metropolis algorithm is developed. The iteration procedure of the algorithm is presented;the posterior distribution of each parameter is simulated;and the parameter estimators and MTBF are obtained. Given the actual MTBF as standard value, the proposed method and LSE are applied to the same real case respectively. The results indicate that when sample size n <= 10, relative errors of the proposed method lie between 4.43% and 7.19%, which are smaller than those of LSE. The proposed Bayesian MTBF estimating method is better than LSE and suitable for NC machine tools under small samples.
In this paper, optimisation algorithms are successfully applied to a number of antenna array beampattern synthesis problems including, a Uniform Linear Array (ULA), a ULA with an inactive element, and a 2D Wireless Se...
详细信息
ISBN:
(纸本)9781467369749
In this paper, optimisation algorithms are successfully applied to a number of antenna array beampattern synthesis problems including, a Uniform Linear Array (ULA), a ULA with an inactive element, and a 2D Wireless Sensor Network (WSN) array. The algorithms presented include a Greedy algorithm (GDA), a metropolis algorithm (MA), and a Genetic algorithm (GA).
This paper provides a general procedure to estimate structural vector autoregressions. The algorithm can be used in constant or time-varying coefficient models, and in the latter case, the law of motion of the coeffic...
详细信息
This paper provides a general procedure to estimate structural vector autoregressions. The algorithm can be used in constant or time-varying coefficient models, and in the latter case, the law of motion of the coefficients can be linear or nonlinear. It can deal in a unified way with just-identified (recursive or nonrecursive) or overidentified systems where identification restrictions are of linear or of nonlinear form. We study the transmission of monetary policy shocks in models with time-varying and time-invariant parameters.
The article examines a hybrid multi-scale numerical algorithm that models surface reactions in the framework of the lattice gas model allowing for lateral interaction between adsorbed particles. The model is called Qu...
详细信息
Quantum effects in many-body systems of 4 He at low temperature are studied in a two dimensional droplet geometry using a path integral simulation of worldlines of 4 He atoms. The implementation of an effective Metrop...
详细信息
Quantum effects in many-body systems of 4 He at low temperature are studied in a two dimensional droplet geometry using a path integral simulation of worldlines of 4 He atoms. The implementation of an effective metropolis-Hastings algorithm is discussed in some detail. We investigate the dependency on multiple parameters: droplet diameter, worldline lengths, number of particles involved, and investigate their effects on the energy, heat capacity and RMS-distance between particles. The cases of Bose-Einstein and Boltzmann statistics, and of interacting and free systems are compared. We find that Bose-Einstein statistics start affecting the interacting systems around 3K, a much higher temperature than expected. We discuss the implication the finite-size space and low density of the simulation volumes may have on these re- sults. The free systems have small differences in energy, with a larger difference in heat capacity than expected, likely due to finite-size effects. The RMS-distance shows that the lack of periodic boundary allows the particles to escape their re- spective potential wells, and diffuse to the domain walls. We also discuss possible future extensions to three dimensions, calculation of su- perfluid density, and effects of entanglement on the entropy.
The metropolis-adjusted Langevin algorithm (MALA) is a metropolis Hastings method for approximate sampling from continuous distributions. We derive upper bounds for the contraction rate in Kantorovich-Rubinstein-Wasse...
详细信息
The metropolis-adjusted Langevin algorithm (MALA) is a metropolis Hastings method for approximate sampling from continuous distributions. We derive upper bounds for the contraction rate in Kantorovich-Rubinstein-Wasserstein distance of the MALA chain with semi-implicit Euler proposals applied to log-concave probability measures that have a density w.r.t. a Gaussian reference measure. For sufficiently "regular" densities, the estimates are dimension-independent, and they hold for sufficiently small step sizes h that do not depend on the dimension either. In the limit h down arrow 0, the bounds approach the known optimal contraction rates for overdamped Langevin diffusions in a convex potential. A similar approach also applies to metropolis Hastings chains with Ornstein-Uhlenbeck proposals. In this case, the resulting estimates are still independent of the dimension but less optimal, reflecting the fact that MALA is a higher order approximation of the diffusion limit than metropolis Hastings with Ornstein-Uhlenbeck proposals.
This paper deals with the atom energy mean value of the platinum nanoparticles of various size (from 300 to 3000 atoms that approximately corresponds to the transition threshold from the icosahedral structure to the f...
详细信息
This paper deals with the atom energy mean value of the platinum nanoparticles of various size (from 300 to 3000 atoms that approximately corresponds to the transition threshold from the icosahedral structure to the face-centered cubic one) on the face-centered cubic lattice and on the five-fold symmetry one, with the application of the modified metropolis algorithm based on the Monte-Carlo method. When calculating the energy the quantum Sutton-Chen potential is used.
We use a metropolis algorithm to calculate the finite temperature spectral weight of three related models that have identical quasiparticles at T=0, if the exchange favors the appearance of a ferromagnetic background....
详细信息
We use a metropolis algorithm to calculate the finite temperature spectral weight of three related models that have identical quasiparticles at T=0, if the exchange favors the appearance of a ferromagnetic background. The low-energy behavior of two of the models remains equivalent at finite temperature, however that of the third does not because its low-energy behavior is controlled by rare events due to thermal fluctuations, which transfer spectral weight well below the T=0 quasiparticle peaks and generate a pseudogaplike phenomenology. Our results demonstrate that having T=0 spectra with similar quasiparticles is not a sufficient condition to ensure that two models are equivalent, i.e., that their low-energy properties are similar. We also argue that the pseudogaplike phenomenology is quite generic for models of t−J type, appearing in any dimension and for carriers injected into both ferromagnetic and antiferromagnetic backgrounds.
Aiming at the large bias of LSE (Least Squares Estimation) in estimating MTBF (mean time between failures) under a small sample of data, a Bayesian MTBF estimating method is proposed for NC (numerical control) machine...
详细信息
ISBN:
(纸本)9781467391672
Aiming at the large bias of LSE (Least Squares Estimation) in estimating MTBF (mean time between failures) under a small sample of data, a Bayesian MTBF estimating method is proposed for NC (numerical control) machine tools. To solve difficulty in directly presenting the prior distributions of Weibull parameters, an expert-judgment method which incorporates prior information is developed to indirectly obtain Weibull parameters' prior distributions. Aiming at the problem that analytic solutions to Weibull parameters' posterior distributions and estimators are impossible to obtain, a metropolis algorithm is developed. The iteration procedure of the algorithm is presented;the posterior distribution of each parameter is simulated;and the parameter estimators and MTBF are obtained. Given the actual MTBF as standard value, the proposed method and LSE are applied to the same real case respectively. The results indicate that when sample size n≤10, relative errors of the proposed method lie between 4.43% and 7.19%, which are smaller than those of LSE. The proposed Bayesian MTBF estimating method is better than LSE and suitable for NC machine tools under small samples.
暂无评论