排序方式: 共有127条查询结果,搜索用时 15 毫秒
61.
核磁共振测深(MRS)探水仪探测到的纳伏级微弱信号极易受到各种环境噪声的干扰, 严重影响信号特征参数的准确提取, 导致后续反演解释错误率增高. 针对这一难题, 提出了基于独立成分分析的快速固定点算法进行信噪分离. 首先分析了该算法用于全波MRS信号消噪的适用性; 其次, 采用数字正交法解决欠定盲源分离问题, 提出了频谱校正法实现分离信号幅值的有效恢复. 仿真结果表明, 该算法能够有效地实现全波MRS信号的信噪分离, 且数据拟合后初始振幅和弛豫时间的相对误差小于± 5.00%; 通过与其他经典算法的对比分析, 进一步证明了该算法消噪性能的优越性. 将该算法应用到野外实测信号处理, 结果证明其能有效滤除环境噪声. 相似文献
62.
Ma Manjun Li Dong 《Annals of Differential Equations》2005,21(4):580-586
In this paper we apply a cone theoretic fixed-point theorem proved by Kras-nosel'skii to obtain sufficient conditions for the existence of positive solutions to some boundary value problems for a class of functional difference equations. We consider the case that the nonlinear term satisfies asymptotically linear growth. 相似文献
63.
Zhan Bing BAI Wei Gao GE 《数学学报(英文版)》2006,22(6):1825-1830
In this paper, we generalize the fixed point theorem of cone expansion and compression of norm type to the theorem of functional type. As an application, the existence of positive solutions for some fourth-order beam equation boundary value problems is obtained. The emphasis is put on that the nonlinear term is dependent on all lower order derivatives. 相似文献
64.
Continuous Selection, Collectively Fixed Points and System of Coincidence Theorems in Product Topological Spaces 总被引:2,自引:0,他引:2
Xie Ping DING 《数学学报(英文版)》2006,22(6):1629-1638
Some new continuous selection theorems are first proved in noncompact topological spaces. As applications, some new collectively fixed point theorems and coincidence theorems for two families of set-valued mappings defined on product space of noncompact topological spaces are obtained under very weak assumptions. These results generalize many known results in recent literature. 相似文献
65.
We study the existence of solutions to the second order three-point boundary value problem: where 0 <η< 1, α∈R, and f : [0, 1]×R×R→R, Ii: R×R→R, Ji : R×R→R(i=1,2,…k) are continuous. Our results is new and different from previous results. In particular, we obtain the Green function of the problem, which makes the problem simpler. 相似文献
66.
NI Xiao-hong GE Wei-gao 《数学季刊》2005,20(4):380-384
In this paper, the authors study the existence of positive solution of the following BVP on the semi-infinite interval. By considering characterization of the nonlinearity, they obtain some new existence results. 相似文献
67.
1.考题呈现近日一次高三模拟考中有如下考题:已知抛物线y2=4x上有一点A(1,2),过点A作抛物线的两条动弦AB和AC,且AB⊥AC,问:直线BC是否过定点?若过定点,求出该定点;若不过,请说明理由. 相似文献
68.
This paper presents some fixed point theorems for expansion selfmaps on complete cone metric spaces. 相似文献
69.
Using fixed point methods, we prove the Hyers-Ulam-Rassias stability and superstability of Jordan homomorphisms (Jordan *-homomorphisms), and Jordan derivations (Jordan *-derivations) on Banach algebras (C*-algebras) for the generalized Jensen-type functional equationwhere r is a fixed positive real number in (1, ∞). 相似文献
70.
本文首次通过借助Kakutani-Fan-Glicksberg固定点定理和非线性标量化,研究了向量值映射的Benson锥鞍点定理.然后,通过使用该Kakutani-Fan-Glicksberg固定点定理,同样得到了集值映射的锥松鞍点定理. 相似文献