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布尔函数的自相关原点矩
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作者 徐结绿 徐汉良 吕述望 《通信学报》 EI CSCD 北大核心 2003年第1期39-44,共6页
本文给出布尔函数的自相关原点矩这一概念,讨论布尔函数密码学特征在自相关原点矩上的数值表现,得到了平衡布尔函数、仿射函数、Bent函数以及部分Bent函数的自相关原点矩的数值特征。
关键词 布尔函数 自相关原点 Walsh循环谱 仿射函数 BENT函数 仿射函数 密码学
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基于分数低阶矩的图像阈值检测和颗粒度分析算法 被引量:1
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作者 胡学龙 王志坚 《中国图象图形学报》 CSCD 北大核心 2008年第10期1821-1824,共4页
为了在进行病变组织检查时,能检测出微小的病变硬化组织,在介绍α稳定分布和与之对应的分数低阶统计量(FLOS)(即分数低阶矩,FLOM)的基础上,给出了非高斯条件下基于分数低阶统计量的阈值检测方法、图像颗粒度分布函数和自相关矩,并首先... 为了在进行病变组织检查时,能检测出微小的病变硬化组织,在介绍α稳定分布和与之对应的分数低阶统计量(FLOS)(即分数低阶矩,FLOM)的基础上,给出了非高斯条件下基于分数低阶统计量的阈值检测方法、图像颗粒度分布函数和自相关矩,并首先以超声医学图像为例,分别用高斯分布的方法和α稳定分布方法对超声医学图像进行阈值检测;然后对经过阈值检测后的图像,利用数学形态学方法计算水平方向和垂直方向的颗粒度分布函数;最后求出两个方向的相关系数。实验结果表明,基于分数低阶统计量的阈值检测和颗粒度分析方法优于传统的高斯分析与处理方法。 展开更多
关键词 分数低阶统计量 分数低阶 阈值检测 颗粒度 自相关矩 数学形态学
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Parameters effects on spiking deconvolution of land seismic data 被引量:1
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作者 MOHAMED Mhmod FENG Xuan XU Cong 《Global Geology》 2015年第4期226-231,共6页
Spiking deconvolution is a standard Wiener Levinson algorithm. The autocorrelation of the design time gate is computed and there is a specified taper on the design gate before the autoeorrelation is done. The standard... Spiking deconvolution is a standard Wiener Levinson algorithm. The autocorrelation of the design time gate is computed and there is a specified taper on the design gate before the autoeorrelation is done. The standard equations are set up, prewhitening is added to the zero lag value of the autocorrelation and the matrix is inverted to derive the spiking operator. In this study, the authors describe a technique for performing spiking deconvolution on prestack time migration (PSTM) data, to test the effect of operator length and percent prewhitening in spiking deconvolution and apply spiking deconvolution trace by trace, with operator lengths 15ms, 10 ms and 5 ms when percent prewhitening 0% , 40ms and 60ms for percent prewhitening 1%. The results show when prewhitening is 0% the shorter operator gives better results, but when value of prewhitening is bigger than 0% it is better to use longer operator lengths. 展开更多
关键词 spiking deconvolution prewhitening operator length PSTM data
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CONSTRUCTIONOFACLASSOFPNSEQUENCESWITHPRIMENUMBERPERIODSOF4t+1FORM
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作者 Yang Fengfan Bi Guangguo Department of Radio Engineering,Southeast UniversityNanjing 210096,P.R.China 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 1996年第1期118-120,共3页
A class of new PN sequence with prime number periods of 4t +1 form (t is an integer)is constructed.The advantage of these PN sequencs over the m(M) sequence is their large number of alternative periods.They hav... A class of new PN sequence with prime number periods of 4t +1 form (t is an integer)is constructed.The advantage of these PN sequencs over the m(M) sequence is their large number of alternative periods.They have good pseudo random characteristics demonstrated by the expression of periodic autocorrelation function found out in this paper. 展开更多
关键词 CODING autocorrelation function MATRIX PN sequences quadratic element finite field
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An Improved Markov Chain Model Based on Autocorrelation and Entropy Techniques and Its Application to State Prediction of Water Resources 被引量:2
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作者 ZHOU Ping ZHOU Yuliang +4 位作者 JIN Juliang LIU Li WANG Zongzhi CHENG Liang ZHANG Libing 《Chinese Geographical Science》 SCIE CSCD 2011年第2期176-184,共9页
According to the relationships among state transition probability matrixes with different step lengths, an improved Markov chain model based on autocorrelation and entropy techniques was introduced. In the improved Ma... According to the relationships among state transition probability matrixes with different step lengths, an improved Markov chain model based on autocorrelation and entropy techniques was introduced. In the improved Markov chain model, the state transition probability matrixes can be adjusted. The steps of the historical state of the event, which was significantly related to the future state of the event, were determined by the autocorrelation technique, and the impact weights of the event historical state on the event future state were determined by the entropy technique. The presented model was applied to predicting annual precipitation and annual runoff states, showing that the improved model is of higher precision than those existing Markov chain models, and the determination of the state transition probability matrixes and the weights is more reasonable. The physical concepts of the improved model are distinct, and its computation process is simple and direct, thus, the presented model is sufficiently general to be applicable to the prediction problems in hydrology and water resources. 展开更多
关键词 improved Markov chain model AUTOCORRELATION ENTROPY annual precipitation annual runoff genetic algorithm
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