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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

股票群的隨機行走模型與內在結構 - 以1996-1999年美國股票S&P500為例之初步分析 / Random walk model and underlying structure - a primitive study of collections of US stocks over 1996-1999

黃鈺峰, Huang, Yu Feng Unknown Date (has links)
我們從計算股價的相關矩陣,然後利用隨機矩陣定理的結果,了解到股票市場並非符合隨機過程的預測,進而得知股票對股票之間具有關聯性,然其長時距下股票價格對數報酬的變化會呈現隨機行走的模式,因此我們對其結果提出二種不同的耦合隨機行走模型,試圖闡釋股票市場間的關聯性可融合到耦合隨機行走模型之中,並藉由均方對數報酬(mean square log-return,MSLR)來探討此事情。 最後,為了瞭解關聯性的關係,並利用其來了解股票市場內部結構的特性,因此我們利用股價的相關矩陣來建構最小展開樹進行分析,發現當時間尺度越大其圖形越密集,中心幾乎為「GE」這家公司,因此其股票市場具有一定的判斷指標。 / By means of calculating the correlation matrix of the price of stock and using the results of random matrix theorems,we learned that the stock market does not match the prediction of stochastic processes and the stock-stock is correlated。However,stock’s price log-return changes under long time scale will appear random walk model. Therefore,we propose two kinds of the different coupled random walk model,that try to explain the correlation between the stock markets can be integrated into the coupled random walk model,and using the mean square log-return( MSLR) to investigate this issue。 Finally,to understand the relationship of correlation matrix and by using it to know the characteristics of the underlying structure of the stock market,we use the correlation matrix of the price to construct the minimum spanning tree for analysis。The results showed that when the time scale is greater, the graphics are more intensive,and the center is almost the same company,"GE", indicating that the stock market has a certain judgment index。
2

離散條件機率分配之相容性研究 / On compatibility of discrete conditional distributions

陳世傑, Chen, Shih Chieh Unknown Date (has links)
設二個隨機變數X1 和X2,所可能的發生值分別為{1,…,I}和{1,…,J}。條件機率分配模型為二個I × J 的矩陣A 和B,分別代表在X2 給定的條件下X1的條件機率分配和在X1 給定的條件下X2的條件機率分配。若存在一個聯合機率分配,而且它的二個條件機率分配剛好就是A 和B,則稱A和B相容。我們透過圖形表示法,提出新的二個離散條件機率分配會相容的充分必要條件。另外,我們證明,二個相容的條件機率分配會有唯一的聯合機率分配的充分必要條件為:所對應的圖形是相連的。我們也討論馬可夫鏈與相容性的關係。 / For two discrete random variables X1 and X2 taking values in {1,…,I} and {1,…,J}, respectively, a putative conditional model for the joint distribution of X1 and X2 consists of two I × J matrices representing the conditional distributions of X1 given X2 and of X2 given X1. We say that two conditional distributions (matrices) A and B are compatible if there exists a joint distribution of X1 and X2 whose two conditional distributions are exactly A and B. We present new versions of necessary and sufficient conditions for compatibility of discrete conditional distributions via a graphical representation. Moreover, we show that there is a unique joint distribution for two given compatible conditional distributions if and only if the corresponding graph is connected. Markov chain characterizations are also presented.

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