基于Vague方法与PROMETHEE方法相结合的黑启动路径评估

首先提出基于方案隶属集与非隶属集的Vague集形成方式;进而提出基于Vague集及PROMETHEE方法的多属性方案排序新方法;最后把新方法用于黑启动方案的排序决策。将由初始属性值组成的初始决策矩阵利用Vague集正反两方面考虑问题的思维方式进行模糊化,一方面保留了各属性独有的特性;另一方面将所有属性转化到相同标度下进行比较,使各个属性的客观本质得到尽可能多的保留及利用。然后利用偏好函数准确地量化了各个方案属性之间的综合占优关系,得到更为准确可信的排序结果。天津电网黑启动路径的评估结果验证了方法的有效性。     

Color‐emotion associations,designing color schemes for urban environment‐architectural settings

Color in urban design has become an important issue, each city may present different colors which help to define and describe its architectural features. In the study, color in urban design with architectural setting is studied, façade colors are analyzed with a specific emphasis on the following research questions; “Can color schemes be designed in respect to color‐emotion associations? ” and “Are color‐emotion associations affective while designing architectural setting‐urban environment?.” Non‐color experts, 170 people, from different European and non‐European countries were asked to match the most appropriate adjectives with the given street views in accordance to their color schemes. In the first step, the effect of color is identified in relation to architectural environment‐urban setting, second the relative effect of color is studied as a component of the material. A categorical specification on color cognition and linguistic level of representation is attempted. The results can be a starting point to highlight the importance of preparing color schemes in regard to color‐emotion associations. Abstract color schemes may also provide us an idea about image setting, especially at design process stage. In the study, keywords are linked as environment‐response pairs; such as quiet, calming, lively, exclusive, reserved, and natural. Human psychophysical structure such as “warm‐cool,” “heavy‐light” in regard to visualizing certain colors are evaluated and described in terms of building materials.     

基于模糊综合评判选择机械运动方案

本文运用形态学矩阵法得出了蜂窝煤成型机的18种机械运动方案,根据机构的相容性和尽量使机构简单的原则,初选了两种机械运动方案.运用模糊综合评判法,从两种可用的机械运动方案中选择出最合理的一种机械运动方案.     

闸门瞬间开启水流的WENO格式数值计算

应用高精度WENO(Weighted Essentially Non-oscillatory)格式求解一维圣维南方程组,建立了闸门瞬间开启水流数值计算的高分辨率数学模型.求解方程时,采用有限体积法积分方程,应用高精度WENO格式确定有限体积交界面处的物理量通量.采用该模型模拟了闸门瞬间全开时洪水波的运动过程,并将计算值与理论解进行了比较,结果表明这类格式精度高,稳定性能好,能够很好地模拟像闸门瞬间开启水流的一类间断解问题.     

解四阶抛物型方程的两层显式差分格式

给出了一个求解四阶抛物型方程的两层十点显式差分格式,证明了其截断误差为ο(τ2 h4),稳定性条件为r=hτ4≤37894.     

Flat families by strongly stable ideals and a generalization of Gröbner bases

Let J be a strongly stable monomial ideal in S=K[x₀,…,x_n] and let Mf(J) be the family of all homogeneous ideals I in S such that the set of all terms outside J is a K-vector basis of the quotient S/I. We show that an ideal I belongs to Mf(J) if and only if it is generated by a special set of polynomials, the J-marked basis of I, that in some sense generalizes the notion of reduced Gröbner basis and its constructive capabilities. Indeed, although not every J-marked basis is a Gröbner basis with respect to some term order, a sort of reduced form modulo I∈Mf(J) can be computed for every homogeneous polynomial, so that a J-marked basis can be characterized by a Buchberger-like criterion. Using J-marked bases, we prove that the family Mf(J) can be endowed, in a very natural way, with a structure of an affine scheme that turns out to be homogeneous with respect to a non-standard grading and flat in the origin (the point corresponding to J), thanks to properties ofJ-marked bases analogous to those of Gröbner bases about syzygies.     

High-order Compact Schemes for Nonlinear Dispersive Waves

High-order compact finite difference schemes coupled with high-order low-pass filter and the classical fourth-order Runge–Kutta scheme are applied to simulate nonlinear dispersive wave propagation problems described the Korteweg-de Vries (KdV)-like equations, which involve a third derivative term. Several examples such as KdV equation, and KdV-Burgers equation are presented and the solutions obtained are compared with some other numerical methods. Computational results demonstrate that high-order compact schemes work very well for problems involving a third derivative term.     

Family of quadratic spline difference schemes for a convection–diffusion problem

We consider the finite difference approximation of a singularly perturbed one-dimensional convection–diffusion two-point boundary value problem. It is discretized using quadratic splines as approximation functions, equations with various piecewise constant coefficients as collocation equations and a piecewise uniform mesh of Shishkin type. The family of schemes is derived using the collocation method. The numerical methods developed here are non-monotone and therefore apart from the consistency error we use Green's grid function analysis to prove uniform convergence. We prove the almost first order of convergence and furthermore show that some of the schemes have almost second-order convergence. Numerical experiments presented in the paper confirm our theoretical results.     

Numerical simulation of stochastic replicator models in catalyzed RNA-like polymers

A stochastic model for replicators in catalyzed RNA-like polymers is presented and numerically solved. The model consists of a system of reaction–diffusion equations describing the evolution of a population formed by RNA-like molecules with catalytic capabilities in a prebiotic process. The diffusion effects and the catalytic reactions are deterministic. A stochastic excitation with additive noise is introduced as a force term. To numerically solve the governing equations we apply the stochastic method of lines. A finite-difference reaction–diffusion system is constructed by discretizing the space and the associated stochastic differential system is numerically solved using a class of stochastic Runge–Kutta methods. Numerical experiments are carried out on a prototype of four catalyzed selfreplicator species along with an activated and an inactivated residues. Results are given in two space dimensions.     

一类混合MUSCL型E格式收敛性的研究

０．引 言 我们知道ＴＶＤ格式能高效地捕捉激波,特别是在激波附近解不发生振荡,因此在流体力学数值计算中得到了广泛的应用．但在 １９８５年,Ｊ．Ｇｏｏｄｍａｎ和 Ｒ．Ｌｅｖｅｑｕｅ证明了二维守恒型 ＴＶＤ格式至多是一阶精度格式［６］,而 ＭｍＢ格式［１］的提出使构造二维高精度格式有了新的突破．另外,在传统理论下,差分格式的熵条件是很难证明的．文［２］提出了在多维空间变量下的高精度差分格式下收敛性的一般方法．证明中只须假设格式解的一致ｌ∞估计和空间离散熵的弱估计,然后运用 Ｄｉｐｅｒｎａ的唯一性定理［５］…