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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Maximum Likelihood Estimation of Parameters in Exponential Power Distribution with Upper Record Values

Zhi, Tianchen 27 March 2017 (has links)
The exponential power (EP) distribution is a very important distribution that was used by survival analysis and related with asymmetrical EP distribution. Many researchers have discussed statistical inference about the parameters in EP distribution using i.i.d random samples. However, sometimes available data might contain only record values, or it is more convenient for researchers to collect record values. We aim to resolve this problem. We estimated two parameters of the EP distribution by MLE using upper record values. According to simulation study, we used the Bias and MSE of the estimators for studying the efficiency of the proposed estimation method. Then, we discussed the prediction on the next upper record value by known upper record values. The study concluded that MLEs of EP distribution parameters by upper record values has satisfactory performance. Also, prediction of the next upper record value performed well
2

不對稱分配於風險值之應用 - 以台灣股市為例 / An application of asymmetric distribution in value at risk - taking Taiwan stock market as an example

沈之元, Shen,Chih-Yuan Unknown Date (has links)
本文以台灣股價加權指數,使用 AR(3)-GJR-GRACH(1,1) 模型,白噪音假設為 Normal 、 Skew-Normal 、 Student t 、 skew-t 、 EPD 、 SEPD 、與 AEPD 等七種分配。著重於兩個部份,(一) Student t 分配一族與 EPD 分配一族在模型配適與風險值估計的比較;(二) 預測風險值區分為低震盪與高震盪兩個區間,比較不同分配在兩區間預測風險值的差異。 實證分析顯示, t 分配一族與 EPD 分配一族配適的結果,無論是只考慮峰態 ( t 分配與 EPD 分配) ,或者加入影響偏態的參數 ( skew-t 分配與 SEPD 分配) , t 分配一族的配適程度都較 EPD 分配一族為佳。更進一步考慮分配兩尾厚度不同的 AEPD 分配,配適結果為七種分配中最佳。 風險值的估計在低震盪的區間,常態分配與其他厚尾分配皆能通過回溯測試,採用厚尾分配效果不大;在高震盪的區間,左尾風險值回溯測試結果,常態分配與其他厚尾分配皆無法全數通過,但仍以 AEPD 分配為最佳。最後比較損失函數,左尾風險值估計以 AEPD 分配為最佳,右尾風險值則無一致的結果。因此我們認為 AEPD 分配可作為風險管理有用的工具。

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