You are here

TARAFLI ÖRNEKLEME YÖNTEMİ İLE VARYANS AZALTMA

VARIANCE REDUCTION VIA IMPORTANCE SAMPLING

Journal Name:

Publication Year:

Abstract (2. Language): 
Variability always occurs to be the most frighteningphenomena in implementation of various kinds of experiments. We desire to control variability and decrease the variance of experiments in order to be aware of the accuracy of the constructed models and consequently supply reliable results. Importance Sampling, also called Biased Sampling is one of the variance reduction techniques especially used in Monte Carlo Methods. This study includes a researchto gather the appropriate importance sampling density which gives the lowest variance. We illustrate the importance sampling method on an M/M/1 queuing problem involving a limited waiting capacity of 50 of buffer size and solve it with an efficient C coded simulation program. We first execute naïve simulation, afterwards we carried out importance sampling method and supplied meaningful decrease in the estimated variance of the case which queue length ever exceeds buffer size. By this way, one can calculate any expectation that cannot be calculated by analytically. Numerical results indicate that longer tailed proposal distributions provide much more meaningful decrease.
Abstract (Original Language): 
Değişkenlik veya rassal sayılara bağlı hata çeşitli deneylerde ortaya çıkan en korkutucu problemlerdendir. Gerçeğe uygun modeller kurup bunlardan güvenilir sonuçlar elde etmek istenir. Bunun için Monte Carlo uygulamalarında tahmini varyansı azaltan Taraflı Örnekleme (Importance Sampling) yöntemi kullanılabilir. Bu çalışmada en az varyansı veren dağılımlar bulunmaya çalışılmıştır. Bunun için basit bir M/M/1 kuyruk sistemi benzetim modellemesi ile analiz edilmişve 50 birimlik bir ön tamponıun dolup aşılma olasılığı bulunmaya çalışılmıştır. Önce basit Monte Carlo benzetim modeli daha sonar Taraflı Örnekleme benzetim modeli kullanılarak sonuçlar alınmıştır ve sayısal sonuçlar daha uzun kuyruğa sahip dağılımların daha olumlu sonuç verdiğini göstermiştir
35-41

REFERENCES

References: 

Bekaert. P. Sbert. M. and Willems. Y.D.(2000) “Weighted Importance Sampling
Technique for Monte Carlo Radiosity” 11
th
Eurographics Workshop on Rendering.
Brno. Czech Republic.
İstanbul Ticaret Üniversitesi Fen Bilimleri Dergisi Güz 2006/2
41
Dupuis. P. (2005) “Dynamic Importance Sampling for Uniformly Recurrent Markov
Chains” Inst. of Math.
Hesterberg. T. (1995). “Weighted Average ImportanceSampling and Defensive
Mixture Distributions.” Technometrics 37, 2, 185-194
Hörmann. W. and Leydold. J. (2005)”Monte Carlo Integration Using Importance
Sampling and Gibbs Sampling.”
Law. A.M. and Kelton. W.D. (2000) ”Simulation Modelling and Analysis.” Third
Edition. International Editions
Ross. S. (2002) “Stochastic Process Applications.” Fifth Edition.
Sminchisescu. C. and Triggs. B. “Hyperdynamics Importance Sampling” in ECCV
2002.
Touzig. A. Hermann. H. (2003) “General Purpose Software for Monte Carlo
Simulations”, Elsevier.

Thank you for copying data from http://www.arastirmax.com