翻訳と辞書
Words near each other
・ Gamma Phi
・ Gamma Phi Beta
・ Gamma Phi Beta Sorority House
・ Gamma Phi Beta Sorority House (Eugene, Oregon)
・ Gamma Phi Beta Sorority House (Urbana, Illinois)
・ Gamma Phi Circus
・ Gamma Phi Delta
・ Gamma Phi Delta Fraternity
・ Gamma Phi Delta Sorority
・ Gamma Phi Gamma
・ Gamma Phoenicis
・ Gamma Pictoris
・ Gamma Piscis Austrini
・ Gamma Piscium
・ Gamma probe
Gamma process
・ Gamma Pyxidis
・ Gamma ray
・ Gamma Ray (band)
・ Gamma ray (disambiguation)
・ Gamma Ray (EP)
・ Gamma Ray (song)
・ Gamma Ray discography
・ Gamma ray logging
・ Gamma ray observatory
・ Gamma Ray Spectrometer
・ Gamma ray spectrometer
・ Gamma Reticuli
・ Gamma Rho Lambda
・ Gamma Sagittae


Dictionary Lists
翻訳と辞書 辞書検索 [ 開発暫定版 ]
スポンサード リンク

Gamma process : ウィキペディア英語版
Gamma process

A gamma process is a random process with independent gamma distributed increments. Often written as \Gamma(t;\gamma,\lambda), it is a pure-jump increasing Lévy process with intensity measure \nu(x)=\gamma x^\exp(-\lambda x), for positive x. Thus jumps whose size lies in the interval () occur as a Poisson process with intensity \nu(x)dx. The parameter \gamma controls the rate of jump arrivals and the scaling parameter \lambda inversely controls the jump size. It is assumed that the process starts from a value 0 at ''t''=0.
The gamma process is sometimes also parameterised in terms of the mean (\mu) and variance (v) of the increase per unit time, which is equivalent to \gamma = \mu^2/v and \lambda = \mu/v.
==Properties==

Some basic properties of the gamma process are:
;marginal distribution
The marginal distribution of a gamma process at time t, is a gamma distribution with mean \gamma t/\lambda and variance \gamma t/\lambda^2.
;scaling
:\alpha\Gamma(t;\gamma,\lambda) = \Gamma(t;\gamma,\lambda/\alpha)\,
;adding independent processes
:\Gamma(t;\gamma_1,\lambda) + \Gamma(t;\gamma_2,\lambda) = \Gamma(t;\gamma_1+\gamma_2,\lambda)\,
;moments
:\mathbb(X_t^n) = \lambda^\Gamma(\gamma t+n)/\Gamma(\gamma t),\ \quad n\geq 0 , where \Gamma(z) is the Gamma function.
;moment generating function
:\mathbb\Big(\exp(\theta X_t)\Big) = (1-\theta/\lambda)^,\ \quad \theta<\lambda
;correlation
:\operatorname(X_s, X_t) = \sqrt,\ s, for any gamma process X(t) .
The gamma process is used as the distribution for random time change in the variance gamma process.

抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)
ウィキペディアで「Gamma process」の詳細全文を読む



スポンサード リンク
翻訳と辞書 : 翻訳のためのインターネットリソース

Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.