6,138 research outputs found
The political role of the people's liberation army 1949-1973
Get PDFThis thesis is to study the political role of the People's Liberation Army from the approach of structure and function. The framework of the thesis consists of three major parts, first, the influence of Chinese traditional political culture on, and the formation of, the political role of the PL A; second, the influence of domestic political struggles and external military conflicts on the development of the political role of the PLA; and the third, the analysis of the transition of the PLA's political role from the structure and personnel arrangements of the CCPCC Within the above-mentioned three scopes, this thesis make a thorough discussion on the following: (1) The relationship between the structure of the PRC and the formation of the PLA's political role; (2) How has ideology influenced the army's political role; (3) What is Mao's viewpoint and his influence on the development of the army's political role; (4) What is the link between the army and the party, and how has this developed; (6) What accounts for the expansion of the PLA's political functions; (7) What is the influence of political factional struggles on the PLA's political role; (8) Is it political institution or military institution that controls the recruitment of the military elite; (9) What are the disparities between the military elite in handling international conflicts and what are their political considerations; (10) What is the Party's position in the army; (11) How have the Party’s important meetings and personnel arrangements influenced the rise and fall of the PLA's political role
Rethinking Import-substituting Industrialization: Development Strategies and Institutions in Taiwan and China
Get PDFimport-substituting industrialization, export-oriented industrialization, development strategies, institutions
Measurement and simulation for wind noises in the ocean environments with nonlinear internal waves
No full textOcean Ambient Noise Study in the Vicinities of Taiwan: Data Analysis and Numerical Modeling
No full text本研究為瞭解臺灣鄰近海域的環境噪音之變動特性，對主動式聲納和被動式聲納的偵測距離之影響，利用ASIAEX、VANS和OAJEX等實驗所蒐集的環境噪音資料，以統計方法分析噪音位準的變動特性。首先由ASIAEX在大陸棚海域的觀測數據之分析結果顯示：風浪影響環境噪音的最低頻段約為500 Hz；風浪噪音在頻譜位準的衰減斜率將隨海況而變動；以1k Hz的風浪噪音觀察高低海況的噪音位準之標準偏差值，當風速在5 m/s以上時噪音的變動明顯降低；而隨著統計時間越長則噪音位準的變動可能越大，因此提高了噪音位準的不確定性；在台灣鄰近幾處海域的環境噪音分佈的特性都略有差異。其次，建構一噪音數值模式以模擬海表面噪音的聲場特性，由1k Hz的風浪噪音模擬結果顯示，海面環境改變噪音聲源強度是首要影響噪音位準變動的因素，海洋內部環境如非線性內波改變海水聲速對噪音位準的影響則相對有限；從模擬結果與實驗資料比對已經驗證模式的可信度，因此該模式可實際應用到噪音位準的預估中。最後利用ASORPS的聲納效能預估算例，討論噪音位準預估誤差和噪音不確定性對聲納偵測距離的影響，結果顯示ASORPS目前使用的經驗公式對臺灣鄰近海域的噪音位準預估之誤差略大，因此本文提出一改善方法，即建構一海洋環境噪音資料庫，結合實驗資料的統計結果與數值模式的模擬，提供噪音位準的平均值和標準偏差值給予ASORPS，以提高聲納系統的預估效能。This study is to survey the variant characteristics of ocean ambient noise in the vicinities of Taiwan and to understand their effects on detection ranges of active and passive sonar system. The data from the experiments of ASIAEX, VANS, and OAJEX are analyzed by statistical methods to obtain varying characteristics of noise levels. The first study is to analyze the ASIAEX data that were measured on the continental shelf, which indicates the minimum frequency-dependence of wind-wave noise is about 500 Hz. The noise level slopes in noise spectrum are changed with sea states. The standard deviations decrease significantly while wind speeds are over 5 m/s. The uncertainty from noise variance may increase due to the statistical duration. There are some distribution variations of ocean ambient noises in the vicinities of Taiwan. The second study is to develop a noise numerical modeling to simulate the sea surface noise fields. The results show the changes of noise source strength from sea surface are the main factor, and the changes of sound speeds due to nonlinear internal waves in ocean are the second factor. The comparisons of resultes on simulation and data have provided good confidence in this noise modeling, which can be applied to predict noise levels. Moreover, the ASORPS study cases explain the prediction errors and the uncertainty of noise levels on detection ranges of sonar. The results show the errors in the noise levels prediction in the vicinities of Taiwan by using the present empirical formula are a little high. So this study provides a development method that is to construct a database of ocean ambient noise, which integrates with statistical results of measurement data and simulations of numerical model. The mean and standard deviation of noise levels would be provided for ASORPS to improve the prediction performance of sonar.謝誌 i
中文摘要 ii
Abstract iii
目錄 v
表目錄 viii
圖目錄 ix
符號索引 xiii
第1章 緒論 1
1.1 研究背景 2
1.2 研究動機 3
1.3 文獻回顧 4
1.3.1 海洋環境噪音之觀測 5
1.3.2 海洋環境噪音之模擬 10
1.3.3 臺灣鄰近海域之噪音調查 17
1.3.4 海洋環境噪音之應用 19
1.4 研究目的 20
1.5 重要結果 22
1.6 論文架構 24
第2章 研究方法 26
2.1 海洋聲學概論 26
2.1.1 波方程式 27
2.1.2 海洋波導 29
2.1.3 海面下聲源 31
2.1.4 聲壓計算 32
2.1.5 音傳損失 35
2.2 水下聲學量測儀器 41
2.2.1 聲納浮標 42
2.2.2 底碇式水下麥克風 44
2.2.3 錨碇式垂直線陣列 47
2.2.4 繫纜式垂直線陣列 49
2.3 數據分析方法 52
2.3.1 基本統計方法 52
2.3.2 數值分析方法 55
2.4 聲音訊號處理 58
2.4.1 聲音訊號格式之轉換 58
2.4.2 數位濾波器之應用 59
2.4.3 時域與頻域之轉換 61
2.4.4 噪音位準之計算方法 62
2.4.5 雜訊濾除之方法 64
2.5 方向性計算 68
2.5.1 波束形成法 68
2.5.2 噪音垂直方向性 73
2.5.3 噪音水平方向性 77
第3章 海洋環境噪音資料分析 80
3.1 實驗簡介 81
3.1.1 ASIAEX實驗 82
3.1.2 VANS實驗 84
3.1.3 OAJEX實驗 87
3.2 噪音位準變動分析 88
3.2.1 噪音位準的時序分析 89
3.2.2 風浪影響噪音的最低頻率 91
3.2.3 噪音頻譜位準的衰減斜率 94
3.2.4 不同海況的噪音位準分佈 97
3.2.5 不同時間長度的統計分析 98
3.2.6 不同實驗量測的噪音分佈 100
3.3 噪音垂直方向性分析 102
3.4 結果討論 104
第4章 水下噪音數值模擬 105
4.1 基本架構 106
4.2 初始條件和邊界條件 108
4.2.1 噪音模擬的位置及半徑 110
4.2.2 噪音聲源強度 116
4.2.3 噪音接收深度 117
4.2.4 海床地形 117
4.2.5 海床地質 119
4.2.6 海水聲速 121
4.3 音傳計算 121
4.3.1 音傳模式之應用說明 122
4.3.2 音傳計算之結果輸出 122
4.4 噪音聲場計算 123
第5章 海面噪音受環境之擾動 126
5.1 海面風浪的影響 126
5.1.1 噪音聲源強度之推估 127
5.1.2 模式與資料的結果比較 128
5.2 海洋內波的影響 129
5.2.1 海洋環境之建構 130
5.2.2 模式與資料的時序比較 131
5.3 結果討論 133
第6章 結論 134
6.1 研究結果之應用 134
6.2 具體結果 138
6.3 本文貢獻 139
6.4 後續研究 140
參考文獻 142
附錄A 雜訊濾除方法之比較 149
附錄B 雷達影像推估波高之方法 155
附錄C ASORPS簡介 160
附錄D 由噪音遮蔽推估聲納偵測距離之算例 16
Xinjiang (China), folk dancing of Uyghurs
No full textFolk-dance of UighursImage is part of research conducted by Chang Chih-Yi for the article: Land Utilization and Settlement Possibilities in Sinkiang
Author(s): Chang Chih-Yi
Source: Geographical Review, Vol. 39, No. 1 (Jan., 1949), pp. 57-75
Published by: American Geographical Society
Stable URL: http://www.jstor.org/stable/211157http://www.jstor.org/stable/211157Grayscal
Iterative Phase Synchronization for Noncoherent Coded Modulation Systems
No full text隨著現有系統操作在低功率的情況下，turbo principle的解碼方式已成為主流，伴隨而知的同步問題逐漸越來越重要。在此論文裡，我們考慮編碼調製(coded modulation)的系統，此系統並沒有明確的提供同調相位的資訊。我們研究其演算法可針對相位的模糊(phase ambiguity)解決和估測在高斯(AWGN)通道下做模擬。 一個簡單實現的串接式(serially-concatenated)的編碼系統可利用迴旋的方式來解碼並加上相位的估測。在每次的迴旋解碼中，我們利用事後機率來估測相位，並在下一次解碼前做補償。我們將面對不同型態的相位模型做考量，並且得到不錯的錯誤率效果。As communication systems operate at low signal-to-noise ratio conditions, synchronizationay become a serious problem.n the thesis, we consider the coded modulation systems which are not explicitlyrovided with the information of coherent phases. We investigate algorithms for jointarrier phase estimation and ambiguity resolution for the AWGN channel.n easily-implemented serially-concatenated coding system is presented that can oper-te with phase estimation technique which is integrated into the iterative decoding loop.t each iteration, we use soft information from MAP decoder to estimate the carrierhase and compensate it for the next iteration. Various phase models are taken intoonsideration. We can always achieve satisfactory error performance.1 Introduction 1 System Description 3.1 Encoding System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2 Channel Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3 Iterative Decoding . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Code Performance Analysis 10.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.2 Mutual Information Determination . . . . . . . . . . . . . . . . . . . 12 Inner-Decoding Alpgorithm 15.1 Iterative Soft-Decision-Direct . . . . . . . . . . . . . . . . . . . . . . 15.1.1 Log-Likelihood Function . . . . . . . . . . . . . . . . . . . . . 15.1.2 APP-Estimation . . . . . . . . . . . . . . . . . . . . . . . . . 18.2 Exponentially-Decaying Moving Average Filter . . . . . . . . . . . . . 21.3 Phase - Quantization . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Simulation Results 29 Conclusions 35ibliography 3
Using vertical directionality to study the ambient noise fluctuations due to interal waves in South China Sea
No full textA Study on the Origin and Crystallization of Shih-yen-chih
No full textSince Shih-hsiang Chen proposed the evolution of the source of \ue2Shih-yen-chih\ue2, followed by the lyrical tradition that covered Chinese poetics, the subject of \ue2Shih-yen-chih\ue2, has always been the topic by many scholars. There are many different opinions about its\ue2 origin and development, and the important politics and religion values of \ue2Yen Chih\ue2 has also been in Confucian Poetic Teaching. This study attempts to clarify how \ue2Shih-yen-chih\ue2 exerts a strong influence in the lyrical tradition and to sort out the origin and crystallization. Untill the present time, Shih-yen-chih is still a charming topic among the scholar circle.
The author would like to examine three issues of \ue2Shih-yen-chih\ue2 in this thesis. Firstly, \ue2Chih\ue2 is originally a voice of sympathetic literature. Secondly, the meaning of \ue2Chih\ue2 is deepened when presented in different poetic forms. Thirdly, the meaning of poetry is widened when people's inner feelings or aspirations are expressed. Hence, it\ue2s fully clear that \ue2Poems Endowed With Feeling\ue2 is originated from \ue2Shih-yen-chih\ue2 until the end of the Poetry in the Han Dynasty
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