排序方式: 共有63条查询结果,搜索用时 695 毫秒
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In 1975, S.M. Voronin proved the universality theorem for the Riemann zeta-function. This famous theorem is ineffective. Here we survey results related to the effectivization of Voronin’s theorem.
相似文献32.
James M. Calvin Yvonne Chen Antanas ?ilinskas 《Journal of Optimization Theory and Applications》2012,155(2):628-636
We describe an adaptive algorithm for approximating the global minimum of a continuous univariate function. The convergence rate of the error is studied for the case of a twice continuously differentiable function. 相似文献
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A two level global optimization algorithm for multidimensional scaling (MDS) with city-block metric is proposed. The piecewise quadratic structure of the objective function is employed. At the upper level a combinatorial global optimization problem is solved by means of branch and bound method, where an objective function is defined as the minimum of a quadratic programming problem. The later is solved at the lower level by a standard quadratic programming algorithm. The proposed algorithm has been applied for auxiliary and practical problems whose global optimization counterpart was of dimensionality up to 24. 相似文献
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An algorithm of simplicial optimization is proposed where a bi-criteria selection of a simplex for the bi-section is applied. The first criterion is the minimum of estimated Lipschitz lower bound over the considered simplex. The second criterion is the diameter of the simplex. The results of experimental testing are included. 相似文献
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Antanas Žilinskas 《Journal of Global Optimization》2010,48(1):173-182
Construction of global optimization algorithms using statistical models and radial basis function models is discussed. A new
method of data smoothing using radial basis function and least squares approach is presented. It is shown that the P-algorithm
for global optimization in the presence of noise based on a statistical model coincides with the corresponding radial basis
algorithm. 相似文献
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Archiv der Mathematik - In the paper, an absolutely convergent Dirichlet series whose shifts approximate a wide class of analytic functions is constructed. This series is close in the mean to the... 相似文献
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We review and compare two models recently used to describe electronic transport in polymer fibers/nanotubes and carbon nanotubes
including graphene nanoribbons, namely, variable range hopping (VRH) in different versions and their modifications on the
one hand and electric-field-induced phonon-assisted tunneling (PhAT) on the other hand. The VRH model is mainly approved on
behalf of the results of temperature dependences. However, the field dependencies of the conductivity in the framework of
this model remain practically unexplained. At the same time, the PhAT model describes properly not only temperature dependence
of conductivity measured in a wide temperature range, but also conductivity/current dependences on field strength using the
same set of parameters characterizing the materials 相似文献
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Mindaugas Maciulevičius Antanas Vinčiūnas Marijus Brikas Andrei Butsen Natalie Tarasenka Nikolai Tarasenko Gediminas Račiukaitis 《Applied Physics A: Materials Science & Processing》2013,111(1):289-295
Size of nanoparticles is an important parameter for their applications. The real-time monitoring is required for reliable and reproducible production of nanoparticles with controllable size. We present results of our research on development of the system for the online nanoparticle characterization during their production by a laser. The laser ablation chamber which allows measurements of surface plasmon resonance spectra during the nanoparticle generation process has been designed and fabricated. The online characterization system was tested by producing and modification of gold nanoparticles. Nanoparticles were generated by nanosecond-laser (wavelength 1064 nm) ablation of gold target in deionized water, and optimal conditions for the highest nanoparticle productivity were estimated. The mean diameter of nanoparticles was determined using their absorption spectra measured in the real-time during the ablation experiments and from the TEM images analysis, and it varied from 20 to 45 nm. The mismatch between nanoparticle diameters, estimated using these two methods, is due to the polydispersity of the generated nanoparticles. The further experiments of laser-induced modification of colloidal gold nanoparticles were carried out using second harmonic (wavelength 532 nm) of nanosecond Nd:YAG laser and alteration in nanoparticle size were acquired by the online measurement system. 相似文献