The Experts below are selected from a list of 215532 Experts worldwide ranked by ideXlab platform
Wojciech Ziarko - One of the best experts on this subject based on the ideXlab platform.
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RSCTC - Stochastic Approach to rough set theory
Rough Sets and Current Trends in Computing, 2006Co-Authors: Wojciech ZiarkoAbstract:The presentation introduces the basic ideas and investigates the Stochastic Approach to rough set theory. The major aspects of the Stochastic Approach to rough set theory to be explored during the presentation are: the probabilistic view of the approximation space, the probabilistic approximations of sets, as expressed via variable precision and Bayesian rough set models, and probabilistic dependencies between sets and multi-valued attributes, as expressed by the absolute certainty gain and expected certainty gain measures, respectively. The measures allow for more comprehensive evaluation of rules computed from data and for computation of attribute reduct, core and significance factors in probabilistic decision tables.
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Stochastic Approach to rough set theory
Lecture Notes in Computer Science, 2006Co-Authors: Wojciech ZiarkoAbstract:The presentation introduces the basic ideas and investigates the Stochastic Approach to rough set theory. The major aspects of the Stochastic Approach to rough set theory to be explored during the presentation are: the probabilistic view of the approximation space, the probabilistic approximations of sets, as expressed via variable precision and Bayesian rough set models, and probabilistic dependencies between sets and multi-valued attributes, as expressed by the absolute certainty gain and expected certainty gain measures, respectively. The measures allow for more comprehensive evaluation of rules computed from data and for computation of attribute reduct, core and significance factors in probabilistic decision tables.
Neil Shah - One of the best experts on this subject based on the ideXlab platform.
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Quantitative Analysis of the Stochastic Approach to Quantum Tunneling
Physical Review D, 2020Co-Authors: Mark P. Hertzberg, Fabrizio Rompineve, Neil ShahAbstract:Recently there has been increasing interest in alternate methods to compute quantum tunneling in field theory. Of particular interest is a Stochastic Approach which involves (i) sampling from the free theory Gaussian approximation to the Wigner distribution in order to obtain Stochastic initial conditions for the field and momentum conjugate and then (ii) evolving under the classical field equations of motion, which leads to random bubble formation. Previous work showed parametric agreement between the logarithm of the tunneling rate in this Stochastic Approach and the usual instanton approximation. However, recent work [J. Braden , Phys. Rev. Lett. 123, 031601 (2019)PRLTAO0031-900710.1103/PhysRevLett.123.031601] claimed excellent agreement between these methods. Here we show that this Approach does not in fact match precisely; the Stochastic method tends to overpredict the instanton tunneling rate. To quantify this, we parameterize the standard deviations in the initial Stochastic fluctuations by ϵσ, where σ is the actual standard deviation of the Gaussian distribution and ϵ is a fudge factor; ϵ=1 is the physical value. We numerically implement the Stochastic Approach to obtain the bubble formation rate for a range of potentials in 1+1 dimensions, finding that ϵ always needs to be somewhat smaller than unity to suppress the otherwise much larger Stochastic rates toward the instanton rates; for example, in the potential of Braden et al., one needs ϵ≈1/2. We find that a mismatch in predictions also occurs when sampling from other Wigner distributions and in single-particle quantum mechanics even when the initial quantum system is prepared in an exact Gaussian state. If the goal is to obtain agreement between the two methods, our results show that the Stochastic Approach would be useful if a prescription to specify optimal fudge factors for fluctuations can be developed.
Tomislav Prokopec - One of the best experts on this subject based on the ideXlab platform.
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Failure of the Stochastic Approach to inflation beyond slow-roll
Journal of Cosmology and Astroparticle Physics, 2019Co-Authors: Diego Cruces, Cristiano Germani, Tomislav ProkopecAbstract:After giving a pedagogical review we clarify that the Stochastic Approach to inflation is generically reliable only at zeroth order in the (geometrical) slow-roll parameter 1 if and only if 22 6/1, with the notable exception of slow-roll. This is due to the failure of the Stochastic ΔN formalism in its standard formulation. However, by keeping the formalism in its regime of validity, we showed that, in ultra-slow-roll, the Stochastic Approach to inflation reproduces the power spectrum calculated from the linear theory Approach.
Stéphane Azou - One of the best experts on this subject based on the ideXlab platform.
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The effects of digital predistortion in a CO-OFDM system – a Stochastic Approach
IEEE Photonics Technology Letters, 2020Co-Authors: Jacqueline Sime, Pascal Morel, Mohamad Younes, Igor Stievano, Mihai Telescu, Noël Tanguy, Stéphane AzouAbstract:Jacqueline E. Sime et al.: The effects of digital predistortion in a CO-OFDM system-a Stochastic Approach Abstract-Digital predistortion is topic of significant interest in telecommunications-both in the wireless radio field and, more recently, in photonics. In the present letter, the authors undertake a sensitivity analysis of various digital predistortion algorithms. Using recent metamodeling techniques designed for efficient Stochastic analysis, the authors show that using predistortion not only leads to a reduction of the error vector magnitude in general but can also make the system less sensitive to uncertainties.
Mark P. Hertzberg - One of the best experts on this subject based on the ideXlab platform.
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Quantitative Analysis of the Stochastic Approach to Quantum Tunneling
Physical Review D, 2020Co-Authors: Mark P. Hertzberg, Fabrizio Rompineve, Neil ShahAbstract:Recently there has been increasing interest in alternate methods to compute quantum tunneling in field theory. Of particular interest is a Stochastic Approach which involves (i) sampling from the free theory Gaussian approximation to the Wigner distribution in order to obtain Stochastic initial conditions for the field and momentum conjugate and then (ii) evolving under the classical field equations of motion, which leads to random bubble formation. Previous work showed parametric agreement between the logarithm of the tunneling rate in this Stochastic Approach and the usual instanton approximation. However, recent work [J. Braden , Phys. Rev. Lett. 123, 031601 (2019)PRLTAO0031-900710.1103/PhysRevLett.123.031601] claimed excellent agreement between these methods. Here we show that this Approach does not in fact match precisely; the Stochastic method tends to overpredict the instanton tunneling rate. To quantify this, we parameterize the standard deviations in the initial Stochastic fluctuations by ϵσ, where σ is the actual standard deviation of the Gaussian distribution and ϵ is a fudge factor; ϵ=1 is the physical value. We numerically implement the Stochastic Approach to obtain the bubble formation rate for a range of potentials in 1+1 dimensions, finding that ϵ always needs to be somewhat smaller than unity to suppress the otherwise much larger Stochastic rates toward the instanton rates; for example, in the potential of Braden et al., one needs ϵ≈1/2. We find that a mismatch in predictions also occurs when sampling from other Wigner distributions and in single-particle quantum mechanics even when the initial quantum system is prepared in an exact Gaussian state. If the goal is to obtain agreement between the two methods, our results show that the Stochastic Approach would be useful if a prescription to specify optimal fudge factors for fluctuations can be developed.
