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磁巴克豪森噪声对应力非常敏感,是一种操作便捷、检测灵敏度高、重复性好的原位无损应力测量技术,在残余应力测定、零部件应力集中区评价、结构承载应力评估中有广阔的应用前景。工程中铁磁性材料表面平面应力测量时最大主应力及其方向测量是一项亟待解决的难题,提出了一种基于周向磁巴克豪森噪声分布的平面应力测量方法,建立了求解平面应力张量的模型,实现了测量点任意方向的正应力和剪应力解调。实验验证了该方法的有效性,测量结果表明,当主应力大于50 MPa时,实测的最大主应力方向偏差为10°,最大正应力偏差为5 MPa,最大剪应力偏差为6 MPa,具有较高的测量准确度。 相似文献
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针对瞬时欠定盲源信号分离问题,提出一种四阶累积张量分解算法.首先构建观察信号四阶累积协方差,依据源信号具有相互独立且均值为零的性质,对累积协方差化简并扩展到张量域,得到四阶累积张量.采用分层交替最小二乘算法对四阶累积张量进行非负库克分解,求得非负库克模型的参数,同时获得非负混合矩阵并求其伪逆,最终估计出源信号.选用真实的语音信号和生物信号进行仿真实验,结果表明该方法提高了源信号和非负混合矩阵的估计性能. 相似文献
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梯度结构张量分析是近年来引入地震解释领域的一种新的属性分析方法,可用于识别地震数据体中的具有不同纹理特征的沉积地貌单元。在地震剖面上,河道沉积充填模式主要有上超充填、侧向加积、复合充填及杂乱和无反射充填等类型;从图像纹理角度来看,前3种表现为弯曲层状纹理,后2种则为杂乱纹理。以四川盆地北部X地区下侏罗统河流相储层为例,对三维地震数据体开展梯度结构张量分析,提取反映河道纹理特征的各向异性参数,通过地层切片刻画河道地貌单元的形态和空间展布特征,取得了满意效果。与常规方法提取的相干及几何属性比较,该方法的抗噪性更好,对河道等沉积地貌单元的反映更为灵敏。 相似文献
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The emergence of quantum computer will threaten the security of existing public-key cryptosystems, including the Diffie Hellman key exchange protocol, encryption scheme and etc, and it makes the study of resistant quantum cryptography very urgent. This motivate us to design a new key exchange protocol and eneryption scheme in this paper. Firstly, some acknowledged mathematical problems was introduced, such as ergodic matrix problem and tensor decomposition problem, the two problems have been proved to NPC hard. From the computational complexity prospective, NPC problems have been considered that there is no polynomial-time quantum algorithm to solve them. From the algebraic structures prospective, non-commutative cryptography has been considered to resist quantum. The matrix and tensor operator we adopted also satisfied with this non-commutative algebraic structures, so they can be used as candidate problems for resisting quantum from perspective of computational complexity theory and algebraic structures. Secondly, a new problem was constructed based on the introduced problems in this paper, then a key exchange protocol and a public key encryption scheme were proposed based on it. Finally the security analysis, efficiency, recommended parameters, performance evaluation and etc. were also been given. The two schemes has the following characteristics, provable security,security bits can be scalable, to achieve high efficiency, quantum resistance, and etc. 相似文献
110.
The emergence of quantum computer will threaten the security of existing public-key cryptosystems,including the Diffie Hellman key exchange protocol,encryption scheme and etc,and it makes the study of resistant quantum cryptography very urgent.This motivate us to design a new key exchange protocol and encryption scheme in this paper.Firstly,some acknowledged mathematical problems was introduced,such as ergodic matrix problem and tensor decomposition problem,the two problems have been proved to NPC hard.From the computational complexity prospective,NPC problems have been considered that there is no polynomial-time quantum algorithm to solve them.From the algebraic structures prospective,non-commutative cryptography has been considered to resist quantum.The matrix and tensor operator we adopted also satisfied with this non-commutative algebraic structures,so they can be used as candidate problems for resisting quantum from perspective of computational complexity theory and algebraic structures.Secondly,a new problem was constructed based on the introduced problems in this paper,then a key exchange protocol and a public key encryption scheme were proposed based on it.Finally the security analysis,efficiency,recommended parameters,performance evaluation and etc.were also been given.The two schemes has the following characteristics,provable security,security bits can be scalable,to achieve high efficiency,quantum resistance,and etc. 相似文献