总体经验模态分解能量向量用于ECG能量分布的研究

总体经验模态分解(EEMD)改进了经验模态分解(EMD)存在的模态混叠问题, 依据信号自身的波动特点将信号分解, 特别适合非线性非平稳信号的分析处理. ECG信号能量分布有一定的规律, 疾病会引起能量分布的变化, 研究ECG能量分布的改变对心脏疾病的研究和临床诊断有重要意义. 本文将ECG信号通过EEMD方法分解为多个本征模态函数(IMF)分量, 观察IMF分量的波动规律, 指出了ECG信号在不同时间尺度上的波动特点和物理意义. 将IMF分量分别计算能量, 得到ECG的能量向量, 并对健康人和三种心脏疾病患者能量向量进行对比分析. 结果表明心脏疾病导致EEMD能量向量的高频分量显著降低, 尤其是p₁分量具有较好的区分度, 可以作为心脏疾病诊断的参考依据. 相比较传统的频域分析方法单纯关注频率而忽略信号自身特点和信号成分之间的相互作用, EEMD的分解结果依赖于ECG信号本身, 因此更能够反映ECG信号的真实情况, 揭示年龄和疾病对ECG能量分布的影响.     

The contragredient equivalence: Application to solve some matrix systems

In this paper we apply the contragredient equivalence to solve two matrix systems. Firstly, we characterize and build all possible solutions of the matrix system P = XY, Q = YX, giving a recursive formula for the number of contragrediently nonequivalent solutions. And, secondly, we find the solution of the matrix system AX = YC, BY = XD.     

两种χ2形式等价性证明的推广

通过直接计算证明了线性函数拟合情况下两种χ²形式的等价性. 利用简化的R值测量定量地检验了等价性的结论.     

Asymptotic property of linear Volterra difference systems

By using the resolvent matrix and the comparison principle, we investigate the asymptotic behavior of linear Volterra difference systems.     

图簇Gj1j2…jt^S^＊（i）（p,tkm）的伴随多项式的因式分解及色性分析

令S1，k表示k＋1个顶点的星，Pm表示m个顶点的路，G是任意的p阶连通图，设V（Pm）={V1，V2，…，Vm-1，Vm}及相应的度序列为（1，2，…，2，1）。S2km＋1^p（i）表示把kPm的每个分支的第i个顶点Vi分别与星S1,k的k个1度点重迭后得到的图，用Gj1j2…ji^S^＊（i）（p，tkm）表示把tSkm＋1^P（i）的每个分支的k度点分别与图G的顶点uj1，uj2，ujt，ujl（t≤p）重迭后得到的图，这里p≥1，k≥2，m≥3，1≤i≤m，t≥1．我们通过讨论图簇Skm＋1^p（i）,U（k-1）K1、S2rm＋1^P（i），S（2r-1）m＋1^P（i）以及Gj1j2…jt^S＊（i）（p，2rmt），Gj1j2……jt^S＊（i）（2r-1）mt）的伴随多项式的因式分解，证明了它们的补图的色等价图的结构定理，推广了张秉儒证明的文[8]中的定理2和定理4。     

The exciton many-body theory extended to any kind of composite bosons

We have recently constructed a many-body theory for composite excitons, in which the possible carrier exchanges between N excitons can be treated exactly through a set of dimensionless “Pauli scatterings” between two excitons. Many-body effects with free excitons turn out to be rather simple because these excitons are the exact one-pair eigenstates of the semiconductor Hamiltonian, in the absence of localized traps. They consequently form a complete orthogonal basis for one-pair states. As essentially all quantum particles known as bosons are composite bosons, it is highly desirable to extend this free exciton many-body theory to other kinds of “cobosons” — a contraction for composite bosons — the physically relevant ones being possibly not the exact one-pair eigenstates of the system Hamiltonian. The purpose of this paper is to derive the “Pauli scatterings” and the “interaction scatterings” of these cobosons in terms of their wave functions and the interactions which exist between the fermions from which they are constructed. It is also explained how to calculate many-body effects in such a very general composite boson system.     

Indestructibility under adding Cohen subsets and level by level equivalence

We construct a model for the level by level equivalence between strong compactness and supercompactness in which the least supercompact cardinal κ has its strong compactness indestructible under adding arbitrarily many Cohen subsets. There are no restrictions on the large cardinal structure of our model (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Diophantine geometry over groups VI: the elementary theory of a free group

This paper is the sixth in a sequence on the structure of sets of solutions to systems of equations in a free group, projections of such sets, and the structure of elementary sets defined over a free group. In the sixth paper we use the quantifier elimination procedure presented in the two parts of the fifth paper in the sequence, to answer some of A. Tarski’s problems on the elementary theory of a free group, and to classify finitely generated (f.g.) groups that are elementarily equivalent to a non-abelian f.g. free group. Received (resubmission): January 2004 Revision: January 2006 Accepted: January 2006 Partially supported by an Israel Academy of Sciences fellowship.     

广义Hamming重量与码的半线性等价

设σ是域F/b的一个自同构,该文证明两个线性码之间的任一保持一个 广义Hamming重量的σ-半线性同构是一个σ-半线性单项等价.     

Fundamentals of mass measurements

The article makes a bridge between quartz crystal microbalance (QCM) and conventional beam balances revealing the role of the field in mass measurements. Thus, three fundamental principles for mass measurements are formulated and demonstrated: the field principle, the mass sensitivity principle and the general equivalence principle.