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1.
基于二维混沌系统的Hash函数构造算法   总被引:1,自引:0,他引:1  
在分析带有正弦因子的类Hénon混沌系统基础上,提出了一种混沌Hash函数的构造算法.该算法在二维Hénon混沌系统中引入正弦因子进行迭代,产生混沌序列,然后通过混沌调制方式将明文信息注入均匀分布的混沌轨迹中,以轨迹的量化结果作为明文的Hash值.这种混沌Hash函数不仅具有不可逆性、很好的单向性,而且Hash结果的每一比特都与明文和初始条件有着敏感而复杂的非线性关系.仿真实验与结果分析表明,该Hash函数满足一定的安全性要求,构造算法简单易于实现.  相似文献   

2.
为提高水印信息的隐秘性和抗攻击性,将混沌映射运用于数字水印过程中,提出了一种基于广义Ar- nold混沌映射和Hénon混沌映射的小波水印算法。首先用Arnold混沌映射将二值水印图像置乱,作为第一层加密,再利用Hénon混沌序列对水印图像数据进行置换,作为第二层加密,并将加密后的水印图像嵌入到原始图像的DWT域系数中,得到嵌入了水印的图像。混沌映射的伪随机性和初值敏感性保证了水印信息的安全性。实验结果表明,此方法对噪声、压缩、裁切等操作具有很好的鲁棒性。  相似文献   

3.
针对Logistic混沌映射随机序列值分布不均的问题,该文采用了一种Wang-Chen混沌系统加密算法对图像进行加密,并对加密后图像进行了像素点相关性分析和直方图分析。实验结果表明,Wang-Chen混沌算法产生的混沌序列随机性好,密钥空间大;经多次迭代加密后的图像像素点间相关性小,其值小于0或接近于0;加密后的图像RGB分布均匀,加密效果较好,基本达到实验目的。  相似文献   

4.
对于离散非线性混沌系统,提出了利用外来混沌信号驱动系统参数的同步方法,实现了混沌系统在不同参数情况下的同步。通过对H埁non和类H埁non混沌系统进行数值模拟计算表明,此方法是可行的。  相似文献   

5.
为解决彩色二维码易伪造、易携带病毒、抗攻击能力弱等问题,提出一种彩色二维码混沌加密方法.该方法利用Lorenz混沌系统产生索引置乱二维码像素值,采用SHA-256生成加密密钥及Lorenz混沌系统初始值.用DNA序列置换像素值矩阵,将RGB灰度矩阵合成为加密彩色二维码.对该方法的密钥空间、密钥灵敏度、信息熵、抗差分攻击、抗统计攻击和相关性进行了实验验证和分析.实验结果表明,该方法具有较好的伪随机性、防伪造性和抗攻击性.  相似文献   

6.
混沌系统控制与同步可通过优化方法设计控制律引导混沌系统轨道来实现.构造适当的适应度函数,将混沌系统的控制与同步问题转化为一个多维的数值优化问题,然后提出一种新的组合进化算法来求解该优化问题.该算法利用佳点集方法初始化种群个体以保证其均匀分布在搜索空间中.在迭代过程中,组合不同进化算子以产生若干个新的子代个体以保持种群的多样性.以典型的Hénon混沌系统为例进行仿真实验,结果表明了该方法是解决混沌系统控制与同步的一种有效方法.  相似文献   

7.
针对目前混沌系统加密算法中明文相关性差和信息熵低的问题,提出一种基于循环移位和混沌系统的灰度图像加密算法.根据明文图像的统计特征,计算需要循环移位的位数;对灰度图像每一个灰度值进行左循环移位得到移位图像;根据初始条件和参数迭代生成3个不同的Logistic混沌序列;根据生成的混沌序列对移位图像进行加密生成加密图像.基于此,对图像直方图、密钥空间、相关性及信息熵进行测试和分析.理论分析及仿真结果表明该算法加密效率高,抗攻击能力较强,安全性好.  相似文献   

8.
为了提高扩频通信系统的性能,设计分数阶混沌扩频通信系统。采用Adomain分解算法求解分数阶简化Lorenz系统,推导分数阶系统迭代式,得到系统的数值解。对迭代值进行简单的二值量化,生成多组互不相关的混沌伪随机序列。将混沌伪随机序列作为扩频码应用于扩频通信系统。在不同信噪比时,分析不同扩频码对通信系统性能的影响。研究结果表明:基于分数阶简化Lorenz系统生成的伪随机序列更随机,均通过美国国家科学技术研究所(NIST)的统计测试套件(STS)测试,序列的生成速度快;与整数阶混沌系统相比,分数阶扩频系统具有更大的秘钥空间,具有更好的安全性;分数阶混沌扩频通信系统的性能优于Hénon映射、Chen系统、m序列及Gold序列的性能,并且具有更大的多址容量。  相似文献   

9.
一种基于广义Chen''''s混沌系统的图像加密新算法   总被引:10,自引:0,他引:10  
根据高雏混沌系统具有更高安全性的特点,提出一种基于三雏Chen’s混沌系统的数字图像加密新算法,通过王乱图像像素的空间位王和改变像素值来混淆密文图像和明文图像之间的关系。利用Chen’s混沌系统的二雏序列王乱图像像素的空间位王;然后,由Chen’s混沌系统输出的三雏混沌序列得到适合灰度图像或真彩色图像加密的密钥序列,利用混沌密钥序列对王乱图像进行遂像素加密。研究结果表明,该算法具有良好的像素值混淆、扩散性能和较大抵抗强力攻击的密钥空间,加密图像像素值具有类随机均匀分布特性,且相邻像素值具有零相关特性,所提出的方案具有较高安全性。  相似文献   

10.
Logistic混沌序列的随机性分析   总被引:4,自引:0,他引:4       下载免费PDF全文
使用统计检验和ECesato检验2种方法对Logistic混沌序列进行随机性分析,得出了在初值取0.7,而参数μ∈(1.99,2]时将产生具有最佳随机性混沌序列的结论.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

16.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

17.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

18.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

19.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

20.
赵英华 《科技信息》2008,(12):219-220
0.Preface China has long been boasting of its colorful and immense culture which comprises of Taoism,Confucianism and Buddhism.The interwoven influence among the religions on Chinese way of thinking,on the nation's behavior in their social life throughout the long history is beyond list.  相似文献   

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