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kurtosis

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kurtosis n.【統計學】峭度。 kurtosis of frequ...

n. 【統計學】峭度。 kurtosis of frequency curve 頻率曲線峰態。 “coefficient of kurtosis“ 中文翻譯：   峰度系數; 峰態系數“graphic kurtosis“ 中文翻譯：   圖解峰志“kurtosis coefficient“ 中文翻譯：   峰度系數; 峰態系數“kurtosis test“ 中文翻譯：   峰度檢驗“measure of kurtosis“ 中文翻譯：   峰度測度; 峰態度量“normal kurtosis“ 中文翻譯：   正規峰態“population kurtosis“ 中文翻譯：   總體峭度“kurtosis of frequency curve“ 中文翻譯：   頻率曲線的峰度“kurtosi“ 中文翻譯：   屈爾特希“kurtos“ 中文翻譯：   庫爾托什; 屈爾特什“kurtoglu burun“ 中文翻譯：   庫爾特奧盧角“kurtossy“ 中文翻譯：   屈爾特希“kurtoglu“ 中文翻譯：   庫爾特奧盧“kurtov“ 中文翻譯：   庫爾托夫“kurto-“ 中文翻譯：   kurt(o)- 前綴 表示“鼓起”，“凸出”： kurtosis.

kuru

The automatic identification of the modulation types has been applied to many fields such as source identification , interference identification , radio interception , - electronic countermeasures , etc . the modulation recognizer based on the decision - theoretic approach and the constellation diagram is proposed and the signal ' s kurtosis is used as the indicator to differentiate the analogue modulation from the digital modulation 通信信號調制類型的自動識別廣泛應用于信號確認、干擾辨識、無線電偵聽、電子對抗和信號監測等領域。本文提出基于決策論與星座圖的綜合調制識別器，使用信號的峰度區分調制類型是模擬調制還是數字調制。

A new matching method of well - log and seismic data is presented so that two - dimensional distributed seismic attribute can be used in 3d reservoir geological modeling . it is named vertical equivalence method . the seismic attribute classification method based on the geological properties in reservoir geological modeling , seismic wave skewness and kurtosis conception , and the rules of seismic time window selection and attribute analysis are presented 提出了將二維分布的地震屬性用于三維儲層地質建模的井震數據匹配地震屬性縱向等值法、基于儲層地質建模儲層地質屬性的地震屬性分類方法、地震波形偏度與尖度的概念、地震時窗選取準則和地震屬性分析準則，為在大慶油田開展儲層地質建模建立了可選的地震屬性參數表。

Through the i 、 q component of ipix radar sea clutter data “ s histogram analyses and by skewness and kurtosis computed , it is been shown that sea clutter amplitude is not rayleigh distribution ; through the comparison of amplitude histogram and distributed models with the same parameters , it is been shown that hh polarization clutter is lognormal distribution , whereas vv polarization is k - distribution ; at the same time the correlation function and power spectrum density are been analyzed , at last the correlation compound k - distribution stochastic sequences whose covariance matrix is been given are been generated through sirp algorithm 文中先介紹了海雜波幅度的有關模型,通過對ipix雷達海雜波數據的i 、 q分量的直方圖以及傾斜度和峰度進行了分析和計算,證明了海雜波幅度不服從瑞利分布;使用幅度直方圖和相同參數下的各種分布模型進行比較,得出hh極化符合對數正態分布,而vv極化服從k -分布的結論;同時對海雜波的相關函數和功率譜進行了分析,最后使用sirp算法產生了給定協方差矩陣的相關復合k -分布隨機序列。

The signal ' s energy is made unitary by whiten before detection in order to simplify the expression of kurtosis . after that we also make use of the advantage of subspace separation to reduce the rank of the signal . thirdly , in order to suppress the effect of time various channel , the adaptive signal processing techniques are studied and an improved adaptive method based on lms ( least mean square ) is proposed 為了能更好的跟蹤信道的變化，論文還研究了自適應信號處理的方法，并針對最小均方誤差的方法進行了改進，改進后的方法在收斂速度比傳統的最小均方誤差方法有很大改進，并且和傳統方法相比它還有收斂速度對收斂步長不敏感的優點。

The object of this thesis for a master ' s degree is to study the existence of seasonality effect in shanghai and shenzhen a - share market . we use the return data of a - share indices ranging from july 21st , 1997 to the end of year 2000 to study this effect by employing five different asymmetric garch - m models . before the garch analysis this paper studied the detail in very detail and find that the data is not much different from the index returns from developed market : it is fat tailed , with high kurtosis 本研究首先對選取的樣本? ?中國的上海和深圳兩個股票市場a -股綜合指數1997年7月21日到2002年12月31日間1316個交易日的收益率的數據分別進行了深入的分析，發現滬深兩市已經逐步趨于規范化，其指數收益率分布具有明顯的尖峰、厚尾的特點；然后分別運用了ljung - boxq檢驗和增廣的dick - fuller檢驗，發現所研究的兩個市場的收益率都具有明顯的自相關性，并且都是穩定序列；最后利用white異方差檢驗和arch性檢驗，證明了本文所研究的樣本具有明顯的異方差性和顯著的arch效應，因此用自回歸條件異方差模型來研究中國股市的季節效應非常合適。

After analyzing the traditional methods of generating exciting signals in vibration control system of electrodynamic ( electrohydraulic ) shaker , a new method of adjusting the skewness and kurtosis of exciting signals by second phase modulation is proposed . based on this method , a new algorithm for generating super - gaussian and quasi - random vibration exciting signals with specified psd , skewness and kurtosis is proposed . simulation and experimental results validate the algorithm 2 .通過分析目前電動(液)振動臺數字式隨機振動控制系統中廣泛采用的激勵信號生成原理,在其基礎上提出了一種通過二次相位調制來控制激勵信號峭度值和偏斜度值的方法,分別得到了頻譜可控的對稱和非對稱分布超高斯偽隨機激勵信號生成算法,并進行了數值仿真和試驗驗證,為研究頻譜可控的超高斯真隨機激勵信號生成技術奠定了基礎。

The results of the experiment show that the peak value , rms , standard deviation , crest factor , kurtosis value and impulse value of the vibration signals can distinguish between the normal and abnormal conditions of the ball bearing when the level of noise is low 常用包絡解調技術對此類信號進行分析，但易受噪聲影響，使得齒輪或滾動軸承的故障特征難以凸顯。本文從研究相關函數的特性入手，經理論證明，發現自相關函數并不改變調制信號的調制特征，但具有顯著的降噪特點。

The resuts showed that the annual average temperature had an increasing trend ; summer , autumn and winter average temperature also had an increasing trend and the amplitude in winter was bigger ; the change of standard deviation and coefficient of variation were acute during winter ; the coefficients was bigger ; the change of standard deviation and coefficient of variation were acute during winter ; the coefficients of skewness were positive value during summer and autumn ; the kurtosis coefficients were bigger during winter 得出如下結論：和田地區年氣溫有增加的趨勢；夏季、秋季、冬季氣溫也有增加的趨勢且冬季氣溫值增幅較大；標準差及變差系數都是冬季變化較為劇烈；偏度系數在夏季及秋季為正值；峰度系數值在冬季較大。

All those things above bring forward a question of how to effectively perform financial risk management , and var risk management tool emerges as times require . but the computation of the var in most cases is based on the assumption that the rate of return follows a normal distribution . this paper estimates value - at - risk using parametric distributions that capture systematic skewness and kurtosis in returns series 但var的計算方法一直都是基于正態分布假設下的，本文系統研究了一些可以描述時間序列收益率分布的峰度和偏度的一些統計分布，如：正態分布、學生氏- t分布、有偏的學生氏- t分布、廣義誤差分布等。

We firstly smoothed these finger prints by wavelet transform . then we expressed these finger prints by some statistic parameters such as skewness , kurtosis , number of peaks , asymmetry , and the cross - correlation factor . lastly we put these statistic parameters into the artificial neural network for pattern recognition 通過對譜圖波形特性的分析，先對譜圖進行了小波平滑，然后在平滑后的譜圖上提取了表示波形特征的統計指標，最后把統計指標送入人工神經網絡進行模式識別。

Two common defects are founded in bss algorithms based on independent component analysis ( ica ) : the selection of none - linear function ( nlf ) in ica depends on the kurtosis of original signals , which degrades the performance of separation seriously when the observed signals are the mixture of super - gaussian and sub - gaussian signals 2 .對一些現在流行的基于獨立分量分析的盲分離算法進行深入研究后,發現其存在以下兩點共同缺陷:由于算法中非線性函數的選取依賴于源信號的峭度性質,當觀測信號為超高斯和亞高斯混合信號時,分離算法性能急劇下降。

Chapter 4 : applying the definitions of the generalized second and fourth order moments , the beam propagation m2 - factor and the kurtosis parameter of coherent and incoherent combinations of two - dimensional off - axis elegant hermite - gaussian ( ehg ) beams are derived analytically and numerically . and the power in bucket ( pib ) is also presented numerically . our results illustrate the propagation properties of the beam through a first - order optical abcd system 第四章：討論了相干和非相干離軸完美厄密高斯( eleganthermitegaussian ( ehg ) )光束組的傳輸特性，通過解析推導和數值模擬，研究了相干和非相干的離軸ehg光束組的傳輸，得出并比較了相干和非相干的離軸ehg光束組的光束質量因子、陡峭度和筒內的功率( powerinbucket ) 。

The basic principle of variable step - size algorithm is analysed , as the facter of variable step - size algorithm mse , the non - linear function of error signal , autocorrelation of error signal and the kurtosis of error signal is proposed , and four new variable step - size cma is achieved . 3 . the kurtosis of equalizer output as a new variable step - size facter is propose , which provide an alternative method of variable step - size , and a new variable step - size cma by putting it into cma is achieved 3 、分析了將輸出信號的峰度用于步長控制的可行性，為變步長算法步長的控制參量提供了新的選擇，并將其應用于恒模算法的步長控制，得到一種新的恒模改進算法，并通過計算機仿真實驗驗證了改進算法優良的收斂性能。

In audio robust watermark algorithm , watermark is embedded in transform domain by using the speediness , simplicity and multi - resolution of wavelet transform . when extracting watermarking , the audio is decomposed by single - level discrete 1 - d wavelet transform , and watermarking is extracted by ica based on kurtosis maximization . this method ’ s computational cost is low 音頻水印利用小波變換快速、簡單和多分辨率的特點來嵌入水印,提取的時候,先對觀測音頻文件進行一級小波分解,然后用基于最大峰值的ica方法進行水印提取,這種方法避免了其他盲源分離方法必需的求逆運算,所以計算量小。

Secondly , we propose a multi - user detection based on kurtosis . this method can suppress not only mai ( multiple - access interference ) but also isi ( inter - symbol interference ) . all needs in the detection are only the desire user ' s spreading code 并在此基礎上，提出了一種基于峭度的盲檢測方法，這種方法不但可以抑制多址干擾mai ( multiple - accessinterference ) ，還可以抑制符號間干擾isi ( inter - symbolinterference ) ，而且在檢測時只需要期望用戶的擴頻碼信息，是一種全盲檢測方法。

One is the bss based on kernel density estimation ( kde ) and genetic algorithm ( ga ) , the other is the blind deconvolution based on high order cross cumulants and ga . without nlf , the performance of separation in both algorithms is independent with the kurtosis of the sources 兩種算法的實現無需引入非線性函數,因此都與源信號的峭度性質無關;另外,選取全局搜索的遺傳算法進行尋優,避免了梯度法搜索的局部性,使得算法均能收斂到問題的全局最優解。

In this algorithm , a ksnr associated with kurtosis of input signal is defined and its calculating formula is given . the simulation with the mot - radiated data indicates that this algorithm has strong ability to suppress colored non - gaussian noise and big signal - to - noise ratio increment . the a 在研究中，定義了峰度信噪比：推導了其計算公式：并用魚雷輻射噪聲數據對算法進行了仿真研究，結果表明：該算法抑制非高斯環境噪聲的能力強，信噪比增益高。

When applying cma to multiuser communication system , proper initialization or adding some constraints are required due to the multi - modality of cm cost function . a code - constrained cma initialized by delay - hypothesized matched matched filter based on minimum kurtosis criterion is proposed in this paper 由于恒模代價函數的多態性，當其應用于多用戶的環境中需要合適的初始化和增加約束條件以保證其能鎖定于期望用戶信號。

Using the intensity moments method , the beam quality parameters such as the propagation factor ( m2 factor ) , kurtosis parameter ( k parameter ) and point stability , etc . of typical laser beams , e . g . , fgbs , sgbs and hermite - cosh - gaussian ( hchg ) beams , are studied 并且利用強度矩方法對平頂分布光束、厄米?雙曲余弦?高斯光束等具有代表性光束的光束質量(包括光束傳輸因子( m ~ 2因子) 、平等度和瞄準穩定性等)作了研究。