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A novel image encryption scheme based on Keplers third law and random Hadamard transform 被引量:3
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作者 罗玉玲 周戎龙 +2 位作者 刘俊秀 丘森辉 曹弋 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第12期146-159,共14页
In this paper, a novel image encryption scheme based on Keplers third law and random Hadamard transform is proposed to ensure the security of a digital image. First, a set of Kepler periodic sequences is generated to ... In this paper, a novel image encryption scheme based on Keplers third law and random Hadamard transform is proposed to ensure the security of a digital image. First, a set of Kepler periodic sequences is generated to permutate image data, which is characteristic of the plain-image and the Keplers third law. Then, a random Hadamard matrix is constructed by combining the standard Hadamard matrix with the hyper-Chen chaotic system, which is used to further scramble the image coefficients when the image is transformed through random Hadamard transform. In the end, the permuted image presents interweaving diffusion based on two special matrices, which are constructed by Kepler periodic sequence and chaos system. The experimental results and performance analysis show that the proposed encrypted scheme is highly sensitive to the plain-image and external keys, and has a high security and speed, which are very suitable for secure real-time communication of image data. 展开更多
关键词 Kepler&#39s third law random Hadamard transform interweaving diffusion security
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Structural plane recognition from three-dimensional laser scanning points using an improved region-growing algorithm based on the robust randomized Hough transform 被引量:2
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作者 XU Zhi-hua GUO Ge +3 位作者 SUN Qian-cheng WANG Quan ZHANG Guo-dong YE Run-qing 《Journal of Mountain Science》 SCIE CSCD 2023年第11期3376-3391,共16页
The staggered distribution of joints and fissures in space constitutes the weak part of any rock mass.The identification of rock mass structural planes and the extraction of characteristic parameters are the basis of ... The staggered distribution of joints and fissures in space constitutes the weak part of any rock mass.The identification of rock mass structural planes and the extraction of characteristic parameters are the basis of rock-mass integrity evaluation,which is very important for analysis of slope stability.The laser scanning technique can be used to acquire the coordinate information pertaining to each point of the structural plane,but large amount of point cloud data,uneven density distribution,and noise point interference make the identification efficiency and accuracy of different types of structural planes limited by point cloud data analysis technology.A new point cloud identification and segmentation algorithm for rock mass structural surfaces is proposed.Based on the distribution states of the original point cloud in different neighborhoods in space,the point clouds are characterized by multi-dimensional eigenvalues and calculated by the robust randomized Hough transform(RRHT).The normal vector difference and the final eigenvalue are proposed for characteristic distinction,and the identification of rock mass structural surfaces is completed through regional growth,which strengthens the difference expression of point clouds.In addition,nearest Voxel downsampling is also introduced in the RRHT calculation,which further reduces the number of sources of neighborhood noises,thereby improving the accuracy and stability of the calculation.The advantages of the method have been verified by laboratory models.The results showed that the proposed method can better achieve the segmentation and statistics of structural planes with interfaces and sharp boundaries.The method works well in the identification of joints,fissures,and other structural planes on Mangshezhai slope in the Three Gorges Reservoir area,China.It can provide a stable and effective technique for the identification and segmentation of rock mass structural planes,which is beneficial in engineering practice. 展开更多
关键词 3D laser scanning Rock discontinuity structural plane Intelligent recognition Robust randomized Hough transform Improved region growing algorithm
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Laplace Transformation and Ergodic Potential Kernel for q-Process in Random Environment 被引量:2
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作者 LU Ping HU Dihe 《Wuhan University Journal of Natural Sciences》 CAS 2007年第2期218-224,共7页
This paper introduces some concepts such as q- process in random environment, Laplace transformation, ergodic potential kernel, error function and some basic lemmas.We study the continuity and Laplace transformation o... This paper introduces some concepts such as q- process in random environment, Laplace transformation, ergodic potential kernel, error function and some basic lemmas.We study the continuity and Laplace transformation of random transition function. Finally, we give the sufficient condition for the existence of ergodic potential kernel for homogeneous q- processes in random environments. 展开更多
关键词 random transition function transition density func-tion in random environment q-process in random environment Laplace transformation ergodic potential kernel
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Improving the Autoregressive Modeling Method in Random Noise Suppression of GPR Data Using Undecimated Discrete Wavelet Transform 被引量:1
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作者 Behrooz Oskooi Amin Ebrahimi Bardar Alireza Goodarzi 《Journal of Signal and Information Processing》 2018年第1期24-35,共12页
Geophysics has played a significant and efficient role in studying geological structures over the past decades as the goal of geophysical data acquisition is to investigate underground phenomena with the highest possi... Geophysics has played a significant and efficient role in studying geological structures over the past decades as the goal of geophysical data acquisition is to investigate underground phenomena with the highest possible level of accuracy. The ground penetrating radar (GPR) method is used as a nondestructive method to reveal shallow structures by beaming electromagnetic waves through the Earth and recording the received reflections, albeit inevitably, along with random noise. Various types of noise affect GPR data, among the most important of which are random noise resulting from arbitrary motions of particles during data acquisition. Random noise which exists always and at all frequencies, along with coherent noise, reduces the quality of GPR data and must be reduced as much as possible. Over the recent years, discrete wavelet transform has proved to be an efficient tool in signal processing, especially in image and signal compressing and noise suppression. It also allows for obtaining an accurate understanding of the signal properties. In this study, we have used the autoregression in both wavelet and f-x domains to suppress random noise in synthetic and real GPR data. Finally, we compare noise suppression in the two domains. Our results reveal that noise suppression is conducted more efficiently in the wavelet domain due to decomposing the signal into separate subbands and exclusively applying the method parameters in autoregression modeling for each subband. 展开更多
关键词 Ground PENETRATING Radar random Noise Undecimated Discrete WAVELET transform AUTOREGRESSIVE Filter
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AFFINE TRANSFORMATION IN RANDOM ITERATED FUNCTION SYSTEMS
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作者 XIONG Yong(熊勇) +1 位作者 SHI Ding-hua(史定华) 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2001年第7期820-826,共7页
Random iterated function systems (IFSs) is discussed, which is one of the methods for fractal drawing. A certain figure can be reconstructed by a random IFS. One approach is presented to determine a new random IFS, th... Random iterated function systems (IFSs) is discussed, which is one of the methods for fractal drawing. A certain figure can be reconstructed by a random IFS. One approach is presented to determine a new random IFS, that the figure reconstructed by the new random IFS is the image of the origin figure reconstructed by old IFS under a given affine transformation. Two particular examples are used to show this approach. 展开更多
关键词 FRACTAL random iterated function system affine transformation
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Definition of Laplace Transforms for Distribution of the First Passage of Zero Level of the Semi-Markov Random Process with Positive Tendency and Negative Jump
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作者 Tamilla I. Nasirova Ulviyya Y. Kerimova 《Applied Mathematics》 2011年第7期908-911,共4页
One of the important problems of stochastic process theory is to define the Laplace transforms for the distribution of semi-markov random processes. With this purpose, we will investigate the semimarkov random process... One of the important problems of stochastic process theory is to define the Laplace transforms for the distribution of semi-markov random processes. With this purpose, we will investigate the semimarkov random processes with positive tendency and negative jump in this article. The first passage of the zero level of the process will be included as a random variable. The Laplace transforms for the distribution of this random variable is defined. The parameters of the distribution will be calculated on the basis of the final results. 展开更多
关键词 Laplace transforms Semi-Markov random PROCESS random Variable PROCESS with POSITIVE TENDENCY and NEGATIVE JUMPS
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Mean Square Solutions of Second-Order Random Differential Equations by Using the Differential Transformation Method
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作者 Ayad R. Khudair S. A. M. Haddad Sanaa L. Khalaf 《Open Journal of Applied Sciences》 2016年第4期287-297,共11页
The differential transformation method (DTM) is applied to solve the second-order random differential equations. Several examples are represented to demonstrate the effectiveness of the proposed method. The results sh... The differential transformation method (DTM) is applied to solve the second-order random differential equations. Several examples are represented to demonstrate the effectiveness of the proposed method. The results show that DTM is an efficient and accurate technique for finding exact and approximate solutions. 展开更多
关键词 random Differential Equations Stochastic Differential Equation Differential transformation Method
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中国省域数字技术互补的区域联动效应:网络结构作用与空间异质性研究
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作者 孟彦菊 郑瑞杰 +1 位作者 但小锦 何函芮 《科技进步与对策》 北大核心 2026年第1期45-56,共12页
技术互补是实现技术进步的重要路径,探讨数字技术互补的联动效应对于促进区域协调发展具有重要意义。研究发现,2007-2023年我国省域数字技术互补水平呈现上升趋势,数字技术互补的区域联动效应呈现动态分化特征。其中,虹吸效应显著作用... 技术互补是实现技术进步的重要路径,探讨数字技术互补的联动效应对于促进区域协调发展具有重要意义。研究发现,2007-2023年我国省域数字技术互补水平呈现上升趋势,数字技术互补的区域联动效应呈现动态分化特征。其中,虹吸效应显著作用于东北及西北地区,加剧了省际数字技术互补水平的不均衡化;辐射效应则主要集中于长三角地区,对缩小省际数字技术互补水平差距具有积极作用。联动效应转化主要由结构依赖、行动者-关系及时间依赖效应共同驱动,其网络结构以三元组结构为主导,节点属性主要表现为高水平的数字技术互补性与辐射能力。分地区看,东部地区联动效应转化主要取决于结构依赖效应且其强度显著高于中西部地区。分数字技术发展水平看,结构依赖效应仅在高数字技术发展水平地区表现显著;出度指标、数字技术互补指数及地理距离对辐射效应的影响亦在高水平地区表现突出。研究深化了对区域数字技术互补联动规律的理论认识,为制定差异化区域数字发展战略、推动数字技术协同发展提供启示。 展开更多
关键词 数字技术互补 联动效应 转化机制 时间指数随机图模型
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振动作用下换流变阀侧套管法兰应力分布对其疲劳寿命的影响
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作者 颜锐奇 张晋寅 +1 位作者 韦晓星 王仲 《高压电器》 北大核心 2026年第1期143-151,共9页
在换流变压器长期振动载荷下,其阀侧套管金属法兰容易因应力集中而出现疲劳开裂,但如今针对套管法兰应力和疲劳寿命的研究还相对匮乏。文中参考实际套管建立阀侧套管模型,采用有限元仿真方法得到不同振动载荷和套管结构下法兰应力和振... 在换流变压器长期振动载荷下,其阀侧套管金属法兰容易因应力集中而出现疲劳开裂,但如今针对套管法兰应力和疲劳寿命的研究还相对匮乏。文中参考实际套管建立阀侧套管模型,采用有限元仿真方法得到不同振动载荷和套管结构下法兰应力和振动疲劳寿命。研究发现:在不同振动方向下,由于交变应力和静态应力的共同影响,套管法兰在x向振动下疲劳寿命最小,在z向下最大;在不同振动频率或幅值下,法兰疲劳寿命随着交变应力的增大而减小,而危险点处静态应力几乎不变。改变套管结构,发现主要是通过减小静态应力来增大法兰寿命,而法兰受到的交变应力几乎不变。最后采用曲面拟合的方法得到金属法兰应力与疲劳寿命之间的关系。研究结果对预测和提高金属法兰疲劳寿命具有指导意义和工程实用价值。 展开更多
关键词 换流变压器阀侧套管 随机振动 套管法兰 应力响应 疲劳寿命
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Flight Flutter Modal Parameters Identification with Atmospheric Turbulence Excitation Based on Wavelet Transformation 被引量:4
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作者 张波 史忠科 李健君 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2007年第5期394-401,共8页
In view of the feature of flight flutter test data with atmospheric turbulence excitation, a method which combines wavelet transformation with random decrement technique for identifying flight flutter modal parameters... In view of the feature of flight flutter test data with atmospheric turbulence excitation, a method which combines wavelet transformation with random decrement technique for identifying flight flutter modal parameters is presented. This approach firstly uses random decrement technique to gain free decays corresponding to the acceleration response of the structure to some non-zero initial conditions. Then the continuous Morlet wavelet transformation of the free decays is performed; and the Parseval formula and residue theorem are used to simplify the transformation. The maximal wavelet transformation coefficients in different scales are searched out by means of band-filtering characteristic of Morlet wavelet, and then the modal parameters are identified according to the relationships with maximal modulus and angle of the wavelet transform. In addition, the condition of modal uncoupling is discussed according to variation trend of flight flutter modal parameters in the flight flutter state. The analysis results of simulation and flight flutter test data show that this approach is not only simple, effective and feasible, but also having good noise immunity. 展开更多
关键词 flight flutter modal parameters identification atmospheric turbulence excitation wavelet transformation random decrement technique acceleration response
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Lyapunov exponents for continuous random transformations
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作者 ZHU YuJun ZHANG JinLian 《Science China Mathematics》 SCIE 2010年第2期413-424,共12页
In this paper,the concept of Lyapunov exponent is generalized to random transformations that are not necessarily differentiable.For a class of random repellers and of random hyperbolic sets obtained via small perturba... In this paper,the concept of Lyapunov exponent is generalized to random transformations that are not necessarily differentiable.For a class of random repellers and of random hyperbolic sets obtained via small perturbations of deterministic ones respectively,the new exponents are shown to coincide with the classical ones. 展开更多
关键词 random transformation Lyapunov exponent multiplicative ergodic theorem random repeller random hyperbolic set
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采用Transformer-CRF的中文电子病历命名实体识别 被引量:41
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作者 李博 康晓东 +3 位作者 张华丽 王亚鸽 陈亚媛 白放 《计算机工程与应用》 CSCD 北大核心 2020年第5期153-159,共7页
命名实体识别是自然语言处理的基本任务之一。针对中文电子病历命名实体识别传统模型识别效果不佳的问题,提出一种完全基于注意力机制的神经网络模型。实验采用自建真实中文电子病历数据集并对数据集进行人工标注、分词等预处理;对Trans... 命名实体识别是自然语言处理的基本任务之一。针对中文电子病历命名实体识别传统模型识别效果不佳的问题,提出一种完全基于注意力机制的神经网络模型。实验采用自建真实中文电子病历数据集并对数据集进行人工标注、分词等预处理;对Transformer模型进行训练优化,以提取文本特征;利用条件随机场对提取到的文本特征进行分类识别。为验证所提方法的有效性,将构建的Transformer-CRF神经网络模型与其他7种传统模型进行比较研究,实验采用精确率、召回率和F1值三个指标评估模型的识别性能。实验结果显示,在同一语料集下,TransformerCRF模型对身体部位类的命名实体识别效果较好,F1值高达95.02%;且与其他7种传统模型相比,Transformer-CRF模型的精确率、召回率和F1值均较高,在一定程度上验证了所构建模型具有较好的识别性能。 展开更多
关键词 电子病历(EMR) 命名实体识别 transformER 条件随机场(CRF)
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基于特征优选与IPSO-LSTM的变压器故障诊断
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作者 胡俊泽 杨耿煌 +1 位作者 耿丽清 刘新宇 《电气传动》 2026年第1期89-96,共8页
针对变压器故障诊断精度差、准确率低的问题,提出一种基于数据特征优选与改进粒子群优化算法的长短期记忆网络(IPSO-LSTM)的变压器故障诊断方法。首先对原始数据集进行预处理,使用合成少数类样本过采样技术(SMOTE)扩充数据数量;其次利... 针对变压器故障诊断精度差、准确率低的问题,提出一种基于数据特征优选与改进粒子群优化算法的长短期记忆网络(IPSO-LSTM)的变压器故障诊断方法。首先对原始数据集进行预处理,使用合成少数类样本过采样技术(SMOTE)扩充数据数量;其次利用特征比值法扩充特征维数至20维,使用随机森林(RF)算法判断特征重要程度进行特征优选,降低过拟合风险;然后引入自适应惯性权重对PSO算法进行改进,利用改进后的PSO算法来优化LSTM最优超参数;最后输入特征优选后的数据进行变压器故障诊断。结果表明所构建的故障诊断模型诊断精度为91.6%。该优化模型与LSTM,HBA-LSTM和PSO-LSTM诊断模型相比,准确率分别提高了10.12%,5.95%,3.57%,证明IPSO-LSTM诊断模型有更高的诊断准确率,在变压器故障诊断领域有一定的实际意义。 展开更多
关键词 变压器故障诊断 特征优选 随机森林 长短期记忆网络 粒子群优化算法
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基于Transformer编码器的中文命名实体识别模型 被引量:12
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作者 司逸晨 管有庆 《计算机工程》 CAS CSCD 北大核心 2022年第7期66-72,共7页
命名实体识别是自然语言处理中的重要任务,且中文命名实体识别相比于英文命名实体识别任务更具难度。传统中文实体识别模型通常基于深度神经网络对文本中的所有字符打上标签,再根据标签序列识别命名实体,但此类基于字符的序列标注方式... 命名实体识别是自然语言处理中的重要任务,且中文命名实体识别相比于英文命名实体识别任务更具难度。传统中文实体识别模型通常基于深度神经网络对文本中的所有字符打上标签,再根据标签序列识别命名实体,但此类基于字符的序列标注方式难以获取词语信息。提出一种基于Transformer编码器的中文命名实体识别模型,在字嵌入过程中使用结合词典的字向量编码方法使字向量包含词语信息,同时针对Transformer编码器在注意力运算时丢失字符相对位置信息的问题,改进Transformer编码器的注意力运算并引入相对位置编码方法,最终通过条件随机场模型获取最优标签序列。实验结果表明,该模型在Resume和Weibo中文命名实体识别数据集上的F1值分别达到94.7%和58.2%,相比于基于双向长短期记忆网络和ID-CNN的命名实体识别模型均有所提升,具有更优的识别效果和更快的收敛速度。 展开更多
关键词 自然语言处理 中文命名实体识别 transformer编码器 条件随机场 相对位置编码
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Denoising of seismic data via multi-scale ridgelet transform 被引量:4
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作者 Henglei Zhang Tianyou Liu Yuncui Zhang 《Earthquake Science》 CSCD 2009年第5期493-498,共6页
Noise has traditionally been suppressed or eliminated in seismic data sets by the use of Fourier filters and, to a lesser degree, nonlinear statistical filters. Although these methods are quite useful under specific c... Noise has traditionally been suppressed or eliminated in seismic data sets by the use of Fourier filters and, to a lesser degree, nonlinear statistical filters. Although these methods are quite useful under specific conditions, they may produce undesirable effects for the low signal to noise ratio data. In this paper, a new method, multi-scale ridgelet transform, is used in the light of the theory of ridgelet transform. We employ wavelet transform to do sub-band decomposition for the signals and then use non-linear thresholding in ridgelet domain for every block. In other words, it is based on the idea of partition, at sufficiently fine scale, a curving singularity looks straight, and so ridgelet transform can work well in such cases. Applications on both synthetic data and actual seismic data from Sichuan basin, South China, show that the new method eliminates the noise portion of the signal more efficiently and retains a greater amount of geologic data than other methods, the quality and consecutiveness of seismic event are improved obviously as well as the quality of section is improved. 展开更多
关键词 ridgelet transform MULTI-SCALE random noise sub-band decomposition complex Morlet wavelet
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Markov Chains Based on Random Generalized 1-Flipper Operations for Connected Regular Multi-digraphs
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作者 邓爱平 伍陈晨 +1 位作者 王枫杰 胡宇庭 《Journal of Donghua University(English Edition)》 CAS 2023年第1期110-115,共6页
The properties of generalized flip Markov chains on connected regular digraphs are discussed.The 1-Flipper operation on Markov chains for undirected graphs is generalized to that for multi-digraphs.The generalized 1-F... The properties of generalized flip Markov chains on connected regular digraphs are discussed.The 1-Flipper operation on Markov chains for undirected graphs is generalized to that for multi-digraphs.The generalized 1-Flipper operation preserves the regularity and weak connectivity of multi-digraphs.The generalized 1-Flipper operation is proved to be symmetric.Moreover,it is presented that a series of random generalized 1-Flipper operations eventually lead to a uniform probability distribution over all connected d-regular multi-digraphs without loops. 展开更多
关键词 random graph transformation regular multi-digraph Markov chain 1-Flipper triangle reverse
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Theoretical Model and Random Simulation for Nonlinear Interaction of Irregular Waves with Vertical Wall 被引量:3
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作者 Hong, Guangwen Feng, Weibing 《China Ocean Engineering》 SCIE EI 1993年第3期263-288,共26页
According to the theoretical solutions for the nonlinear three-dimensional gravity surface waves and their interactions with vertical wall previously proposed by the lead author, in this paper an exact second-order ra... According to the theoretical solutions for the nonlinear three-dimensional gravity surface waves and their interactions with vertical wall previously proposed by the lead author, in this paper an exact second-order random model of the unified wave motion process for nonlinear irregular waves and their interactions with vertical wall in uniform current is formulated, the corresponding theoretical nonlinear spectrum is derived, and the digital simulation model suitable to the use of the FFT (Fast Fourier Transform) algorithm is also given. Simulations of wave surface, wave pressure, total wave pressure and its moment are performed. The probability properties and statistical characteristics of these realizations are tested, which include the verifications of normality for linear process and of non-normality for nonlinear process; the consistencies of the theoretical spectra with simulated ones; the probability properties of apparent characteristics, such as amplitudes, periods, and extremes (maximum and minimum, positive and negative extremes). The statistical analysis and comparisons demonstrate that the proposed theoretical and computing models are realistic and effective, and estimated spectra are in good agreement with the theoretical ones, and the probability properties of the simulated waves are similar to those of the sea waves. At the same time, the simulating computation can be completed rapidly and easily. 展开更多
关键词 ALGORITHMS Coastal engineering Fast Fourier transforms Mathematical models PROBABILITY random processes Retaining walls Surface waves
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The Estimation of Radial Exponential Random Vectors in Additive White Gaussian Noise
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作者 Pichid KITTISUWAN Sanparith MARUKATAT Widhyakorn ASDORNWISED 《Wireless Sensor Network》 2009年第4期284-292,共9页
Image signals are always disturbed by noise during their transmission, such as in mobile or network communication. The received image quality is significantly influenced by noise. Thus, image signal denoising is an in... Image signals are always disturbed by noise during their transmission, such as in mobile or network communication. The received image quality is significantly influenced by noise. Thus, image signal denoising is an indispensable step during image processing. As we all know, most commonly used methods of image denoising is Bayesian wavelet transform estimators. The Performance of various estimators, such as maximum a posteriori (MAP), or minimum mean square error (MMSE) is strongly dependent on correctness of the proposed model for original data distribution. Therefore, the selection of a proper model for distribution of wavelet coefficients is important in wavelet-based image denoising. This paper presents a new image denoising algorithm based on the modeling of wavelet coefficients in each subband with multivariate Radial Exponential probability density function (PDF) with local variances. Generally these multivariate extensions do not result in a closed form expression, and the solution requires numerical solutions. However, we drive a closed form MMSE shrinkage functions for a Radial Exponential random vectors in additive white Gaussian noise (AWGN). The estimator is motivated and tested on the problem of wavelet-based image denoising. In the last, proposed, the same idea is applied to the dual-tree complex wavelet transform (DT-CWT), This Transform is an over-complete wavelet transform. 展开更多
关键词 MMSE ESTIMATOR RADIAL EXPONENTIAL random VECTORS Wavelet transform Image DENOISING
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A Novel Technique for Evaluating Failure Probability of Random Structure
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作者 Seifedine Kadry Abdelkhalak El Hami 《World Journal of Mechanics》 2015年第8期139-150,共12页
The purpose of this article is to develop a new methodology to evaluate the statistical characteristic of the response of structures subjecting to random excitation, by combining the Finite Element Method (FEM) with t... The purpose of this article is to develop a new methodology to evaluate the statistical characteristic of the response of structures subjecting to random excitation, by combining the Finite Element Method (FEM) with the Transforming Density Function (TDF). Uncertainty modeling of structure with random variables encourages the coupling of advanced TDF for reliability analysis to analyze problems of stochastic mechanical systems. The TDF is enthusiastically applicable in the situation where the relationship between input and output of structures is available in explicit analytical form. However, the situation is much more involved when it is necessary to perform the evaluation of implicit expression between input and output of structures through numerical models. For this aim, we propose a new technique that combines the FEM software, and the TDF method to evaluate the most important statistical parameter the Probability Density Function (PDF) of the response where the expression between input and output of structures is implicit. Once the PDF is evaluated, all other statistical parameters are derived easily. This technique is based on the numerical simulations of the FEM and the TDF by making a middleware between Finite Element software and Matlab. Some problems, range from simple to complex, of structures are analyzed using our proposed technique. Its accuracy is validated through Monte-Carlo simulation. 展开更多
关键词 random PARAMETER Uncertainty transformING DENSITY Function FINITE ELEMENT Method FINITE ELEMENT Software Matlab Structures
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Subharmonic response of single-degree-of-freedom linear vibroimpact system to narrow-band random excitation
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作者 戎海武 王向东 +2 位作者 罗旗帜 徐伟 方同 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2011年第9期1159-1168,共10页
The subharmonic response of a single-degree-of-freedom linear vibroimpact oscillator with a one-sided barrier to the narrow-band random excitation is investigated.The analysis is based on a special Zhuravlev transform... The subharmonic response of a single-degree-of-freedom linear vibroimpact oscillator with a one-sided barrier to the narrow-band random excitation is investigated.The analysis is based on a special Zhuravlev transformation,which reduces the system to the one without impacts or velocity jumps,and thereby permits the applications of asymptotic averaging over the period for slowly varying the inphase and quadrature responses.The averaged stochastic equations are exactly solved by the method of moments for the mean square response amplitude for the case of zero offset.A perturbation-based moment closure scheme is proposed for the case of nonzero offset.The effects of damping,detuning,and bandwidth and magnitudes of the random excitations are analyzed.The theoretical analyses are verified by the numerical results.The theoretical analyses and numerical simulations show that the peak amplitudes can be strongly reduced at the large detunings. 展开更多
关键词 single-degree-of-freedom linear vibroimpact system subharmonic response Zhuravlev transformation method random averaging method
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