TU-H-CAMPUS-IeP1-01: Bias and Computational Efficiency of Variance Reduction Methods for the Monte Carlo Simulation of Imaging Detectors

2016 ◽  
Vol 43 (6Part37) ◽  
pp. 3776-3776
Author(s):  
D Sharma ◽  
J Sempau ◽  
A Badano
2021 ◽  
Vol 9 ◽  
Author(s):  
Salvador García-Pareja ◽  
Antonio M. Lallena ◽  
Francesc Salvat

After a brief description of the essentials of Monte Carlo simulation methods and the definition of simulation efficiency, the rationale for variance-reduction techniques is presented. Popular variance-reduction techniques applicable to Monte Carlo simulations of radiation transport are described and motivated. The focus is on those techniques that can be used with any transport code, irrespective of the strategies used to track charged particles; they operate by manipulating either the number and weights of the transported particles or the mean free paths of the various interaction mechanisms. The considered techniques are 1) splitting and Russian roulette, with the ant colony method as builder of importance maps, 2) exponential transform and interaction-forcing biasing, 3) Woodcock or delta-scattering method, 4) interaction forcing, and 5) proper use of symmetries and combinations of different techniques. Illustrative results from analog simulations (without recourse to variance-reduction) and from variance-reduced simulations of various transport problems are presented.


2014 ◽  
Vol 955-959 ◽  
pp. 1817-1824 ◽  
Author(s):  
Jiu Ru Dai ◽  
Meng Yi Li ◽  
Wu Wei Li ◽  
Tian Xia ◽  
Zhi Gang Zhang

With the prevalence of credit system, the stipulation of “academic warning” is written into the teaching management constitution by more colleges and universities. However, the establishment of this stipulation hasn’t formed unified and scientific standards at present. This paper aims at studying the credit setting of academic warning through the method of Monte Carlo simulation, and at applying multivariate normal distribution and variance reduction techniques to calculate relatively reasonable academic warning credit line, which provides a new train of thought and a universal method for colleges and universities to set specific standards.


Author(s):  
X. Blanc ◽  
C. Le Bris ◽  
F. Legoll

We give an overview of a series of recent studies devoted to variance reduction techniques for numerical stochastic homogenization. Numerical homogenization requires that a set of problems is solved at the microscale, the so-called corrector problems. In a random environment, these problems are stochastic and therefore need to be repeatedly solved, for several configurations of the medium considered. An empirical average over all configurations is then performed using the Monte Carlo approach, so as to approximate the effective coefficients necessary to determine the macroscopic behaviour. Variance severely affects the accuracy and the cost of such computations. Variance reduction approaches, borrowed from other contexts in the engineering sciences, can be useful. Some of these variance reduction techniques are presented, studied and tested here.


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