简化迭代正则化方法和后验参数选取法

1IntroductionQuite a lot of mathematical problems can be pre-sented in the formAx=y,(1.1)whereAis a mapping from a distance spaceXintoanother distance spaceY.For a given effecty,weshould find its causex.Because this equationis oftenill-posed[1],regularization methods should be used tosolve it.Among those methods the most popular onesperhaps are the Tikhonov regularization method[2]anditerative Tikhnov method[2].In Ref.[4,5],the au-thors put forward a new method called A-smooth regu-larizat…     

A Note on Vulnerability in Graphs of Diameter Five （ Ⅱ ）

The line persistence of a graph G, Pt （ G ） is the minimum number of lines which must be removed to increase the diameter of G. In Ref. [7] （J. Shanghai Univ., 2003,7（4）：352-357）, we gave a characterization of graphs of diameter five with ρ1 （ G ）≥2. In this paper we will show that each of the 8 special graphs Xi （ i = 1,2,3,4,5,6,7,8） listed in condition （2） of Theorem 1 in Ref. [7] can not be deleted. Therefore the results we obtained in Ref. [7] can not in general be improved.     

带有磁性杂质的量子线中自旋相关传输

1IntroductionQuantumtransport in mesoscopic systems has beenextensively investigated in the past two decade[1].Since Wees ,et al.[2]and Wharam,et al.[3]discov-ered the phenomenon of conductance quantization ofan electron through a narrow two-di mensional con-striction,there have been a number of other works ,which are concentrated on studying electron scatteringfrom i mpurities in a narrow quantum conductorwire[4-10].Bagwell and Avishai ,et al.[4-6]have exam-ined the influences of scattering …     

A Novel Absorbing Boundary Condition for the Frequency—Dependent Finite—Difference Time—Domain Method

A new absorbing boundary condition(ABC) for frequency-dependent finite-difference time-domain algorithm for the arbitrary dispersive media is presented.The concepts of the digital systems are introduced to the (FD)^2TD method.On the basis of digital filter disigning and vector algebra,the absorbing boundary condition under arbitrary angle of incidence are derived.The transient electromagnetic problems in two-dimensions and three-dimensions are calculated and the validity of the ABC is verified.     

Vibration response analysis of 2-DOF locally nonlinear systems based on the theory of modal superposition

1 Introduction ? Low frequency vibration has an important effect on body comfort and on the fatigue of a vibrating system. Nearly all actual vibrating systems are nonlinear. However, nonlinear behaviors are not always observed in the system dynamics. Thus…     

Stabilization of Delayed Networks with Different Nodes

In this paper,the control of complex delayed networks with different nodes is proposed.Firstly,the stabilization of coupled networks with time delay is investigated.By constructing a Lyapunov function,a linear feedback controller design procedure for the networks is converted to the problem of solving a set of linear matrix inequalities.Then the results are extended to networks with both delayed dynamical nodes and delayed couplings.It is shown that the stabilization of complex networks is determined by the dynamics of each uncoupled node,coupling matrix and feedback gain matrix of networks.Two examples are simulated.In the first example,a network with 10 nodes consisting of Lorenz systems and systems proposed by Zhang in 2009 is given.It is found that the network states are divergent without control,and convergent under designed linear feedback controllers.In the second example,a larger network with 100 nodes consisting of delayed Chen systems and delayed Lorenz systems is given.The proposed method is also effective for large scale networks.     

Nonlinear decoupling controller design based on least squares support vector regression

INTRODUCTION Most practical systems are multivariate nonlin- ear systems. In general, the MIMO (multiple inputs and multiple outputs) systems are coupled. This cou- pling affects the effectiveness of a specific loop con- troller on the corresponding output, and in some case, may become serious and cause many difficulties to the control system design. How to decouple the mul- tivariate systems and design practical controllers is one of the major issues in nonlinear control area. In recen…     

DS-CDMA的MIMO系统中的空时多用户检测

Space-time signal processing based on multiple-input multiple-output（MIMO） systems is an active research field in which interfering signals are cancelled and multiuser detection is achieved using space diversity. In a Rayleigh fading channel, space-time block cedes using multiple transmitting antennas can improve system performance and reduce bit-error-rate for multiuser detection. In this paper, several antenna configurations are designed for DS-CDMA communication in MIMO systems. Space-time linear multinser detection and space-time serial interference cancellation multiuser detection are simulated. Bit-error-rate and computation complexities of the two methods are compared. Conclusions are given in the end.     

英国文学

正The Power of the Written Word There are more books published per person in the UK than in any other country in the world.In 2011,an amazing 229million were sold in Britain—despite an economic recession and the growing popularity of new digital readers.The     

Admissibility Conditions for Symbolic Sequences in Dynamics of Digital Filter with Two＇s Complement Arithmetic

In this paper, we discuss a class of piecewise linear hyperbolic maps on the 2-torus. These maps arise in the second-order digital fdter with two＇ s complement arithmetic. By introducing codings underlying the map operations, we give some admissibility conditions for symbolic sequences and find some periodic properties of these symbolic sequences. Then we use these conditions to check the admissibility of periodic symbol sequences.     

GENERAL ADMISSIBLE LINEARESTIMATORS IN RESTRICEDGROWTH CURVE MODEL

In this paper, we give a class of fuation and use to dicuss general admissibility according to general optimality ceriteria defined uader restricted growth curve model. General admissible characterization are obtained. Moreover, these conditions are then utilize to characterize infulueace that restrictions involved in growth curve model have on the class of admissible linear estimators     

不确定切换奇异系统的鲁棒容许性分析:切换Lyapunov函数方法(英文)

研究了一类不确定离散切换线性奇异(SLS)系统任意切换律下的鲁棒容许性问题.假设系统参数不确定性满足范数有界条件.首先,采用切换Lyapunov函数方法,给出了一些新的保证名义离散SLS系统任意切换律下正则、无脉冲以及渐进稳定的充分条件,且条件表示为线性矩阵不等式形式.基于获得的条件,进一步给出了保证不确定离散SLS系统任意切换律下鲁棒容许的条件.将正常切换系统的切换Lyapunov函数方法推广到奇异切换系统.数值例子说明了该方法保守性的降低及可行性.     

University Students’ Conceptualization and Interpretation of Topographic Maps

This study investigates the strategies and assumptions that college students entering an introductory physical geology laboratory use to interpret topographic maps, and follows the progress of the students during the laboratory to analyze changes in those strategies and assumptions. To elicit students’ strategies and assumptions, we created and refined a topographic visualization test that was administered before and after instruction to 26 students during the first semester of the study and to 92 students during the second semester. To more deeply understand how students think about and conceptualize topographic maps, we focused on eight individual students who were interviewed about their pretest and posttest answers as well as videotaped during three laboratory sessions. We found that even students who claim never to have worked with topographic maps often perform impressively on their pretests by making useful assumptions about symbolic topographic information. Some students, however, begin with less productive assumptions that may be unfamiliar to some instructors (e.g., thinking that the spacing of contour lines indicates elevation instead of slope). Initial success should not be misinterpreted, however, as an integrated understanding of topographic maps. Only in posttest interviews do most students express explanations integrating multiple normative assumptions. In addition to highlighting the strategies and assumptions that college students use to interpret topographic maps, we outline the implications of these findings for the design of learning objectives, curricular activities, and assessments for topographic lessons in introductory college geology courses and the training of future geoscientists.     

关子二维保面积映象的研究

本文研究了二维保面积映象的稳定周期轨道、同周期分岔、倍周期分岔及Kolm—Jogorov熵,发现周期N轨道的失稳曲线在局部区域互相交错和打结,得到了同周期分岔条件及区分三种同周期分岔类型的解析判据,和倍周期序列分岔率及标度变换因子,对描速映象混沌程度的Kolmogorov熵也进行了计算。     

Y上连续的连通集值映射的周期轨道

文章定义了Y空间上连续的连通集值映射及其周期轨道,探索了Y空间上连续的连通集值映射与y上的连续自映射之间的关系,得到了关于Y上连续的连通集值映射的两个定理。     

阻尼RLW方程的周期强解

文中用Galerkin方法和先验估计证明了带有阻尼项的RLW方程周期边界问题周期强解的存在唯一性,并在较弱的光滑性条件下,得到了强解的光滑性。     

一类两自由度碰撞振动系统的周期运动稳定性与分岔

本文建立了一类两自由度变碰撞面的碰撞振动系统动力学模型,获得了系统的周期响应,推导出系统n-1周期运动的四维Poincaré映射。利用Poincaré映射方法,对系统单碰撞周期运动的稳定性与分岔进行分析,分析了系统n-1周期运动的Hopf分岔、周期倍化分岔及强共振情况下的亚谐分岔,研究了当分岔参数变化时碰撞振动系统由概周期碰撞运动向混沌运动的演化过程,为冲击振动系统的优化设计提供了理论依据。     

闭自集值映射的本质不动集

首先给出了关于在度量空间中闭自集值映射具有不动集的性质,并且在这个性质的条件下,证明了这些不动集具有本质性。     

具时变时滞模糊BAM神经网络周期解的稳定性

本文利用Lyapunov泛函及不等式(2ab≤ra2+1/rb2,r>0)导出了判定模糊BAM(bi-directional associa-tive memory)神经网络周期解的存在性与稳定性的一些充分条件,得到了其周期解全局指数稳定性的一些新的简单判据.