修正的LMS方法

ＢｉｔｍｅａｄＲ．Ｒ和ＡｎｄｅｒｓｏｎＤ．Ｏ在文献［１］中为任意线性方程组的求解提出了一种颇为有效的算法，称为ＬＭＳ方法．文献［２］详细地论述了算法的收敛性，指出收敛极限是方程组的最小二乘解．本文为使解线性方程组的ＬＭＳ算法具有更广泛、更方便的应用性．对文献［２］中的ＬＭＳ算法作了修正．理论和实践证明修正后的算法是成功的．     

SOME NEW FAMILIES OF SDSS AND HADAMARD MATRICES

ＳＯＭＥＮＥＷＦＡＭＩＬＩＥＳＯＦＳＤＳＳＡＮＤＨＡＤＡＭＡＲＤＭＡＴＲＩＣＥＳ￥ＸｉａＭｉｎｇｙｕａｎ（夏明远）（Ｄｅｐｔ．ｏｆＭａｔｈ．，ＨｕａｚｈｏｎｇＮｏｒｍａｌＵｎｉｕ．，Ｗｕｈａｎ４３００７０，Ｃｈｉｎａ．）Ａｂｓｔｒａｃｔ：Ｉｎｔｈｉｓ...     

任意长—维DFT的MIMD并行算法

本文提出了共享与分布式存储计算机上任意长—维ＤＦＴ的ＭＩＭＤ并行算法，若Ｎ＝Ｏ（ｐ，ｑ），则算法需要次算术运算。其中，Ｐ与Ｎ可为任意自然数，分别表示处理机台数与ＤＦＴ长度．本文算法具有很高的并行效率．     

一类大系统模糊随机多目标决策的建模与求解方法

本文提出和建立了一类大系统模糊随机多目标决策（ＦＳＭＯＤＭ）模型，讨论了模糊事件的模糊概率的若干基本性质．在此基础上，将ＦＳＭＯＤＭ模型转化为清晰的多目标决策模型，并给出了递阶分解协调求解方法．把该模型应用到大连市水资源与经济发展规划研究中取得了令人满意的结果．     

CHEBYSHEV PSEUDOSPECTRAL DOMAIN DECOMPOSITION METHOD OF ONE－DIMENSIONAL ELLIPTIC PROBLEMS

ＣＨＥＢＹＳＨＥＶＰＳＥＵＤＯＳＰＥＣＴＲＡＬＤＯＭＡＩＮＤＥＣＯＭＰＯＳＩＴＩＯＮＭＥＴＨＯＤＯＦＯＮＥ－ＤＩＭＥＮＳＩＯＮＡＬ　ＥＬＬＩＰＴＩＣ　ＰＲＯＢＬＥＭＳＸｉｏｎｇＹｕｅｓｈａｎ（Ｄｅｐｔ，ｏｆＭａｔｈ．，ＮａｔｉｏｎａｌＵｎｉｖ．ｏｆＤ...     

NONTRIVIAL SOLUTIONS OF COMPETITIVE-DIFFUSIVE SYSTEMS WITH SMALL DIFFUSION

ＮＯＮＴＲＩＶＩＡＬＳＯＬＵＴＩＯＮＳＯＦＣＯＭＰＥＴＩＴＩＶＥ－ＤＩＦＦＵＳＩＶＥＳＹＳＴＥＭＳＷＩＴＨ　ＳＭＡＬＬＤＩＦＦＵＳＩＯＮＬｉＤａｈｕａ（Ｄｅｐｔ．ｏｆＭａｔｈ．，ＨｕａｚｈｏｎｇＵｎｉｖ．ｏｆＳｃｉ．＆Ｔｅｃｈ．，Ｗｕｈａｎ４３００７...     

α-CARLESON MEASURE AND BLOCH FUNCTIONS ON BOUNDED SYMMETRIC DOMAINS OF C~n

α－ＣＡＲＬＥＳＯＮＭＥＡＳＵＲＥＡＮＤＢＬＯＣＨＦＵＮＣＴＩＯＮＳＯＮＢＯＵＮＤＥＤＳＹＭＭＥＴＲＩＣＤＯＭＡＩＮＳＯＦＣ~ｎＯｕｙａｎｇＣａｉｈｅｎｇ（欧阳才衡）（ＷｕｈａｎＩｕｓｔ．ｏｆＭａｔｈ．Ｓｃｉ．，ＣｈｉｎｅｓｅＡｃａｄ．ｏｆＳｃｉ．，...     

STRONG SUBORDINATION OF SYMMETRIC DIRICHLET FORMS

ＳＴＲＯＮＧＳＵＢＯＲＤＩＮＡＴＩＯＮＯＦＳＹＭＭＥＴＲＩＣＤＩＲＩＣＨＬＥＴＦＯＲＭＳＹＩＮＧＪＩＡＮＧＧＡＮＧＭａｎｕｓｃｒｉｐｔｒｅｃｅｉｖｅｄＭａｙ９，１９９５．ＲｅｖｉｓｅｄＭａｒｃｈ２１，１９９６．ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈ...     

EXPONENTIAL DICHOTOMIES,HOMOCLINIC ORBITS AND METHODS OF MELNIKOV

ＥＸＰＯＮＥＮＴＩＡＬＤＩＣＨＯＴＯＭＩＥＳ，ＨＯＭＯＣＬＩＮＩＣＯＲＢＩＴＳＡＮＤＭＥＴＨＯＤＳＯＦＭＥＬＮＩＫＯＶ（曾唯尧，钱祥征，王志成）￥ＺｅｎｇＷｅｉｙａｏ（Ｄｅｐｔ．ｏｆＭａｔｈ．，ＨｕｎａｎＬｉｇｈｔＩｎｄｕｓｔｒｉａｌＣｏｌｌｅｇｅ，...     

关于随机优化算法的几点讨论

关于随机优化算法的几点讨论李晓莉，雷功炎（河南驻马店师专，北京大学数学系）ＳＯＭＥＤＩＳＣＵＳＳＩＯＮＳＡＢＯＵＴＳＴＯＣＨＡＳＴＩＣＯＰＴＩＭＩＺＡＴＩＯＮＡＬＧＯＲＩＴＨＭＳ￥ＬｉＸｉａｏ－ｌｉ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，Ｚ...     

Effect of channel connection on flow and salinity distribution of Danshuei River estuary

Numerical models are often used to evaluate the potential impact of human alteration of natural water bodies and to help the design the alternation to mitigate its impacts. A vertical (laterally integrated) two-dimensional hydrodynamic model was expanded to include the capability of simulating river loops as well as tributaries. The model was performed and applied to the Danshuei River estuarine system in northern Taiwan which consists of three major tributaries: the Tahan Stream, Hsintien Stream, Keelung River, and one river loop under the Chung-Hsin Bridge. The expanded model was reverified with observational field data of 2000. The verified model was then used to hindcast the river hydrodynamic conditions with a loop connection between the Danshuei River and Keelung River, which existed prior to 1965. It was found that the configuration of river loop connection has significant impacts on the residual transport along the connecting channel and the salinities in the connected river branches. The results show that the model may provide an ideal tool for management decision.     

非定常线性化Navier-Stokes方程的非协调流线扩散有限元法分析

对非定常线性化Navier-Stokes方程提出了非协调流线扩散有限元方法．用向后Euler格式离散时间,用流线扩散法处理扩散项带来的非稳定性．速度采用不连续的分片线性逼近,压力采用分片常数逼近．得到了离散解的存在唯一性以及在一定范数意义下离散解的稳定性和误差估计．     

Fast construction of binary ring FCSRs for hardware stream ciphers

Stream ciphers based on linear feedback shift registers have been subject to algebraic attacks. To avoid these kinds of attacks, feedback with carry shift registers (FCSRs) have been proposed as an alternative. They are suitable for hardware implementations. FCSRs have been implemented using ring representation, in order to circumvent some weaknesses in the traditional representations. In this paper, we explore the simplest case of FCSRs, called binary FCSRs, which are common in applications. We give a fast algorithm to construct binary ring FCSRs for hardware stream ciphers.     

Transient Stokes flow over a plane with a moving sleeve

The transient and stationary Stokes flow in the half space over a plane boundary containing a moving sleeve is determined in the case when the sleeve starts att=0 and moves with a constant velocity. Stream line plots showing the convergence towards a stationary state are presented.

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Zusammenfassung Die transiente und die stationäre Stokesschen Strömungen in einem Halbraum über einer, mit einem konstant bewegten Schieber versehener Grenzfläche, wird bestimmt. Stromlinienfiguren, die die Konvergenz gegen einen stationären Zustand zeigen, werden vorgestellt.

     

A parallel derangement generation algorithm

A parallel algorithm to generate allD _n derangements ofn distinct elements is presented in this paper. The algorithm requiresO([D _n /P]nlogn) time whenP processors are available on a Single Instruction Multiple Data Stream (SIMD) computer.     

Effects of variable viscosity on pulsatile flow of blood in a tapered stenotic flexible artery

The objective of the present study is to investigate the effects of variable viscosity on incompressible laminar pulsatile flow of blood through an overlapping doubly constricted tapered artery. To mimic the realistic situation, wall of the artery is taken to be flexible, and physiologically relevant pulsatile flow is introduced. The governing equations of blood flow are made dimensionless. A coordinate transformation is used to make the overlapping doubly constricted wall geometry of tube to a straight tube. Taking advantage of the Stream function–Vorticity formulation, the system of partial differential equations is then solved numerically by finite difference approximations. Effects of Reynolds number, Strouhal number, degree of contraction, tapering angle, and viscosity parameters are presented graphically and analyzed. The results show that formation of stenosis and tapering disturb the flow field significantly, and degree of stenosis is more important in influencing blood flow compared with tapering.     

Book Vignettes

Housner , Melvin , Elementary Probability Theory. Dawes , Clinton J., Biological Techniques in Electron Microscopy. Davis , Lee , W., Elements of Calculus for Technical Students. Pierce , Conway and Smith , R. Nelson , General Chemistry Workbook: How to Solve Chemistry Problems: Fourth Edition. Carter , Joseph L.; Goodman , Howard P.; Hunter , Danny D. and Schelske , Leroy J., Life Science: A Problem Solving Approach. Boyd , Lorenz , Follow the Butterfly Stream. Simon , Hilda , Living Lanterns: Luminescence in Animals.     

Flow past a porous sphere at small Reynolds number

low of an incompressible viscous fluid past a porous sphere has been discussed. The flow has been divided in three regions. The Region-I is the region inside the porous sphere in which the flow is governed by Brinkman equation with the effective viscosity different from that of the clear fluid. In Regions II and III clear fluid flows and Stokes and Oseen solutions are respectively valid. In all the three regions Stokes stream function is expressed in powers of Reynolds number. Stream function of Region II is matched with that of Region I at the surface of the sphere by the conditions suggested by Ochao-Tapia and Whitaker and it is matched with that of Oseen’s solutions far away from the sphere. It is found that the drag on the sphere reduces significantly when it is porous and it decreases with the increase of permeability of the medium.Received: February 7, 2002; revised: April 8, 2003 / June 9, 2004     

Cryptanalysis of the Stream Cipher LEX

Biryukov (The Design of a Stream Cipher LEX, Proceedings of Selected Areas in Cryptography, 2006 Springer, pp 67–75, 2007) presented a new methodology of stream cipher design called leak extraction. The stream cipher LEX, based on this methodology and on the AES block cipher, was selected to round 3 of the eSTREAM competition. The suggested methodology seemed promising, and LEX, due to its elegance, simplicity, and performance, was expected to be selected to the eSTREAM portfolio. In this article we present a key recovery attack on LEX. The attack requires about 2⁴⁰ bytes of key-stream produced by the same key (possibly under many different IVs), and retrieves the secret key in time of about 2¹⁰⁰ AES encryptions. Following a preliminary version of our attack, LEX was discarded from the final portfolio of eSTREAM.     

有限区域求解流函数和速度势的迭代调整方法及其收敛性分析

全球区域求解流函数和速度势的解是唯一的,但有限区域内,由于受区域边界条件限制,流函数和速度势的计算以及风场的分解不是唯一的,减小或消除边界不确定对结果的影响是有限区域求解流函数和速度势以及分解风场最重要的问题．该文在Endlich迭代调整思想上,提出了能准确求解有限区域流函数和速度势且对边界条件要求较低的迭代调整方法．该方法也能准确地分解和重建风场,且风场重建的误差非常小．对该迭代方法的收敛性进行分析,发现其收敛性与不同方向网格的格距和调整系数有关．最后将该方法应用到Arakawa A-D网格和不规则区域,验证了该方法的可靠性．