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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

希爾柏特黃轉換於非穩定時間序列之分析:用電量與黃金價格 / Non-stationary time series analysis by using Hilbert-Huang transform: electricity consumption and gold price volatility

張雁茹, Chang, Yen Rue Unknown Date (has links)
本文有兩個研究目標,第一個是比較政大用電量與氣溫之間的相關性,第二則是分析影響黃金價格波動的因素。本文使用到的研究方法有希爾柏特黃轉換(HHT)與一些統計值。   本研究使用的分析數據如下:政大逐時用電量、台北逐時氣溫以及倫敦金屬交易所(London Metal Exchange)的月平均黃金價格。透過經驗模態分解法(EMD),我們可以將分析數據拆解成數個互相獨立的分量,再藉由統計值選出較重要的分量並分析其意義。逐時用電量的重要分量為日分量、週分量與趨勢;逐時氣溫的重要分量為日分量與趨勢;月平均黃金價格的重要分量則是低頻分量與趨勢。 藉由這些重要分量,我們可以更加了解原始數據震盪的特性,並且選出合理的平均週期將所有的分量分組,做更進一步的分析。逐時用電量與逐時氣溫分成高頻、中頻、低頻與趨勢四組,其中低頻與趨勢相加的組合具有最高的相關性。月平均黃金價格則是分為高頻、低頻與趨勢三組,其中高頻表現出供需以及突發事件等短週期因素,低頻與歷史上對經濟有重大影響的事件相對應,趨勢則是反應出通貨膨脹的現象。 / There are two main separated researched purposes in this thesis. First one is comparing the correlation between electricity consumption and temperature in NCCU. Another one is analyzing the properties of gold price volatility. The methods used in the study are Hilbert-Huang transform (HHT) and some statistical measures.   The following original data: hourly electricity consumption in NCCU, hourly temperature in Taipei, and the LME monthly gold prices are decomposed into several components by empirical mode decomposition (EMD). We can ascertain the significant components and analyze their meanings or properties by statistical measures. The significant components of each data are shown as follows: daily component, weekly component and residue for hourly electricity consumption; daily component and residue for hourly temperature; low frequency components and residue for the LME monthly gold prices.   We can understand more properties about these data according to the significant components, and dividing the components into several terms based on reasonable mean period. The components of hourly electricity consumption and hourly temperature are divided into high, mid, low frequency terms and trends, and the composition of low frequency terms and trends have the highest correlation between them. The components of LME monthly gold prices are divided into high, low frequency term and trend. High frequency term reveals the supply-demand and abrupt events. The low frequency term represents the significant events affecting economy seriously, and trend shows the inflation in the long run.
2

時間數列模式建立分析應用之研究

朱建萍, ZHU, JIAN-PING Unknown Date (has links)
本文主要在探討如何建立適當的時間數列模式,以應用於預測及控制上。第一章,緒 論。第二章,討論各種型態的時間數列隨機模式,並研究自我相關函數與偏自我相關 函數的性質。第三章,主要在研究單變量時間數列模式建立的方法與步驟及其在預測 上的應用分析,並以建立「台電公司家庭用電量」時間數列模式為例配合說明。第四 章,研究具有動態反應的轉換函數模式及其模式建立的方法與在預測上的應用分析。 第五章,討論含有虛擬變數的動態調停模式,並配合實例說明如何應用動態調停模式 以解決經濟與環境問題。第六章,結論,說明時間數列模式在建立方法上有那些限制 ,以及在應用分析上有那些優缺點;並就「台電家庭用電量」建立時間數列模式俾供 台電在業務企劃上參考或應用。
3

基於EEMD之倒傳遞類神經網路方法對用電量及黃金價格之預測 / Forecasting electricity consumption as well as gold price by using an EEMD-based Back-propagation Neural Network Learning Paradigm

蔡羽青, Tsai, Yu Ching Unknown Date (has links)
本研究主要應用基於總體經驗模態分解法(EEMD)之倒傳遞類神經網路(BPNN)預測兩種不同的非線性時間序列數據,包括政大逐時用電量以及逐日歷史黃金價格。透過EEMD,這兩種資料會分別被拆解為數條具有不同物理意義的本徵模態函數(IMF),而這讓我們可以將這些IMF視為各種影響資料的重要因子,並且可將拆解過後的IMF放入倒傳遞類神經網路中做訓練。 另外在本文中,我們也採用移動視窗法作為預測過程中的策略,另外也應用內插法和外插法於逐時用電量的預測。內插法主要是用於補點以及讓我們的數據變平滑,外插法則可以在某個範圍內準確預測後續的趨勢,此兩種方法皆對提升預測準確度占有重要的影響。 利用本文的方法,可在預測的結果上得到不錯的準確性,但為了進一步提升精確度,我們利用多次預測的結果加總平均,然後和只做一次預測的結果比較,結果發現多次加總平均後的精確度的確大幅提升,這是因為倒傳遞類神經網路訓練過程中其目標為尋找最小誤差函數的關係所致。 / In this paper, we applied the Ensemble Empirical Mode Decomposition (EEMD) based Back-propagation Neural Network (BPNN) learning paradigm to two different topics for forecasting: the hourly electricity consumption in NCCU and the historical daily gold price. The two data series are both non-linear and non-stationary. By applying EEMD, they were decomposed into a finite, small number of meaningful Intrinsic Mode Functions (IMFs). Depending on the physical meaning of IMFs, they can be regarded as important variables which are input into BPNN for training. We also use moving-window method in the prediction process. In addition, cubic spline interpolation as well as extrapolation as our strategy is applied to electricity consumption forecasting, these two methods are used for smoothing the data and finding local trend to improve accuracy of results. The prediction results using our methods and strategy resulted in good accuracy. However, for further accuracy, we used the ensemble average method, and compared the results with the data produced without applying the ensemble average method. By using the ensemble average, the outcome was more precise with a smaller error, it results from the procedure of finding minimum error function in the BPNN training.

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