A fast adaptive spectral graph wavelet method for the viscous Burgers' equation on a star-shaped connected graph

Water wave propagation in an open channel network can be described by the viscous Burgers' equation on the corresponding connected graph, possibly with small viscosity. In this paper, we propose a fast adaptive spectral graph wavelet method for the numerical solution of the viscous Burgers' equation on a star-shaped connected graph. The vital feature of spectral graph wavelets is that they can be constructed on any complex network using the graph Laplacian. The essence of the method is that the same operator can be used for the construction of the spectral graph wavelet and the approximation of the differential operator involved in the Burgers' equation. In this paper, two test problems are considered with homogeneous Dirichlet boundary condition. The numerical results show that the method accurately captures the evolution of the localized patterns at all the scales, and the adaptive node arrangement is accordingly obtained. The convergence of the given method is verified, and efficiency is shown using CPU time.     

驻波演示仪的制作

针对驻波的运动特点和特殊的运动规律,进行了驻波演示仪的设计和制作,非常直观、形象地表现了驻波的运动规律。本文介绍了驻波演示装叠的原理、制作方法及演示效果。     

混凝土断裂的连续-非连续方法

采用有限元形函数作为单位分解函数,位移间断用富集节点的附加自由度表示,建立了允许在单元内部位移非连续的局部富集公式以表征混凝土的开裂区域．富集基函数由节点形函数和节点形函数与间断函数的乘积的并集构成．非连续位移的扩展路径完全与网格结构无关．不同于以非协调应变为基础的嵌入非连续模型,对单元的类型没有限制而且间断位移可以贯穿单元边界．局部富集思想与扩展有限元类似,但富集点自由度保持节点位移的物理意义不变,使相邻单元无需进行富集运算．在变分公式中引入混凝土粘结本构定律,推导了考虑断裂过程区非线性影响的基本方程．对混凝土粘结裂纹扩展的数值模拟说明了该计算方法的有效性．     

On the impossibility of using the longitude of the ascending node of GP-B for measuring the Lense–Thirring effect

The possibility of analyzing the node of the GP-B satellite in order to measure also the Lense–Thirring effect on its orbit is examined. This feature is induced by the general relativistic gravitomagnetic component of the Earth gravitational field. The GP-B mission has been launched in April 2004 and is aimed mainly to the measurement of the gravitomagnetic precession of four gyroscopes carried onboard at a claimed accuracy of 1%. of better. The aliasing effect of the solid Earth and ocean components of the solar K₁ tidal perturbations would make the measurement of the Lense–Thirring effect on the orbit unfeasible. Indeed, the science period of the GP-B mission amounts to almost one year. During this time span the Lense–Thirring shift on the GP-B node would be 164 milliarcseconds (mas), while the tidal perturbations on its node would have a period of the order of 10³ years and amplitudes of the order of 10⁵ mas.     

Is It Possible to Study the Wave Function of 2S Vector Mesons at HERA?

We present a short review of anomalous properties in diffractive photo- and electroproduction of radially excited V(2S) vector mesons. Using the color dipole generalized Balitsky-Fadin-Kuraev-Lipatov phenomenology we analyze anomalous Q ² and energy dependence of the production cross section, V(2S)/V(1S) production ratio, the diffraction slope and anomalous t-behavior of the differential cross section d/dt. The origin of these anomalies is based on the interplay of the nodal structure of V(2S) radial wave function with the energy and dipole size dependence of the dipole cross section and the diffraction slope. We analyze how a different pattern of anomalous behavior of V(2S) production leads to a different position of the node in the wave function and discuss how that node position can be extracted from the data at HERA.     

锥形GRIN透镜的光束宽度和变周期节点

本文由波动方程出发,求得了锥形GRIN(梯度折射率)透镜的光束宽度关系式,并由此确定这种透镜的变周期节点。用几何光学轨迹法也能得到同样的结果。     

光纤CAN网络节点数计算方法

为电动汽车通信网设计了一种中继型节点的光纤CAN(Fibre--CAN)环型总线网络．采用塑料光纤(POF)作为传输介质，用波长为660nm的红光光电收发器件实现光电转换．在对中继型节点的传输延迟进行详细的分析后，结合CAN协议定义的位周期，给出了基于传输延时的网络最大节点数的计算方法．并对该方法进行了实验验证，实验结果与理论计算具有良好的一致性，表明该方法的有效性．     

Lifting,superadditivity, mixed integer rounding and single node flow sets revisited

In this survey we attempt to give a unified presentation of a variety of results on the lifting of valid inequalities, as well as a standard procedure combining mixed integer rounding with lifting for the development of strong valid inequalities for knapsack and single node flow sets. Our hope is that the latter can be used in practice to generate cutting planes for mixed integer programs. The survey contains essentially two parts. In the first we present lifting in a very general way, emphasizing superadditive lifting which allows one to lift simultaneously different sets of variables. In the second, our procedure for generating strong valid inequalities consists of reduction to a knapsack set with a single continuous variable, construction of a mixed integer rounding inequality, and superadditive lifting. It is applied to several generalizations of the 0-1 single node flow set.Received: December 2002, Revised: April 2003, AMS classification: 90C11, 90C27Laurence A. Wolsey: Corresponding author: CORE, Voie du Roman Pays 34, 1348 Louvain-la-Neuve, Belgium. The first author is supported by the FNRS as a research fellow. This paper presents research results of the Belgian Program on Interuniversity Poles of Attraction initiated by the Belgian State, Prime Ministers Office, Science Policy Programming. The scientific responsibility is assumed by the authors.Laurence A. Wolsey: This research was also supported by the European Commission GROWTH Programme, Research Project LISCOS, Large Scale Integrated Supply Chain Optimization Software Based on Branch-and-Cut and Constraint Programming Methods, Contract No. GRDI-1999-10056, and the project TMR-DONET nr. ERB FMRX-CT98-0202.     

Monte Carlo calculations of atoms and molecules

The variational and Green's function Monte Carlo (GFMC) methods can treat many interesting atomic and molecular problems. These methods can give chemical accuracy for up to 10 or so electrons. The various implementations of the GFMC method, including the domain Green's function method and the short-time approximation, are discussed. Results are presented for several representative atoms and molecules.     

基于最少中继节点约束的量子VoIP路由优化策略

量子信息的传输过程中,由于拥塞、链路故障等原因,导致数据分组在路由器排队,产生时延、丢包.为了保证量子Vo IP系统的性能,本文提出了基于最少中继节点约束的路由优化策略.采用基于纠缠交换的中继技术,通过优先选择最少中继节点的量子信道,实现多用户量子Vo IP通信.理论分析和仿真结果表明,当链路出现故障和拥塞时,基于M/M/m型排队系统,采用本策略,当设定量子比特的误码率为0.2,共用信道数目从4增加到8时,量子网络的呼损率由0.25下降到0.024,量子网络的最大吞吐量由64 kbps增加到132 kbps.当设定共用信道数目为4,控制量子比特的误码率从0.3到0.1时,可使量子网络最大吞吐量从41 kbps增加到140 kbps.由此可见,本策略能够极大地提高量子Vo IP网络的性能.