无规取向、无吸收非球形粒子光散射的T-矩阵方法收敛问题的研究:II.椭球体(英文)

较详细地研究了无规取向、无吸收椭球体粒子的T 矩阵收敛问题。首先 ,简要概括了nmax的 3种收敛方案和它们的基本特性。然后 ,应用 1993年提出的数学收敛方法 (M 方法 )和 1998年提出的物理收敛方法 (P 方法 )研究收敛问题。结果表明椭球粒子收敛精度对粒子的尺度参数 ,纵横比以及椭球体的种类 (例如 ,长 扁椭球 )有很强的依赖性。当粒子的尺度参数不太大时 ,甚至在极端纵横比的条件下 ,P 收敛方案优于M 收敛方案。

误差函数计算方法的研究

误差函数已有多种计算方法,其中按e-t2的幂级数展开式为基础的算法,数学上是收敛的,且在科技应用范围内,数值上也是收敛的.数值积分法,如梯形法是计算误差函数更好的方法,文中给出了控制积分变量等分数目的计算公式,并得到了很好的计算结果.

应用人工神经网络识别水淹层

张玎冉文琼等：应用人工神经网络识别水淹层，测井技术，１９９６（３）２０，２１０～２１４。油层水淹后，水淹层的内部物性明显区别于油层的原始状态。由于水淹状况复杂多变，使用一般测井解释方法识别水淹层具有很大困难。本文研究了应用人工神经网络ＢＰ算法处理测井资料来识别水淹层的基本原理和具体实现，给出了ＢＰ算法的改进方法及在两个油田的实际应用效果。

弹/粘塑性圆柱内剪切波的二维数值解

提出了一个根据沿次特征线积分原理求解二维弹／粘塑性剪切应力波传 播问题的数值方法，并计算了呈非线性分布的动剪应力载荷作用于圆柱体一 端时圆柱体的应力波传播问题．弹性剪切波问题的数值解与精确解相符．利 用统计总能量的方法考察和讨论了数值解法的稳定性和收敛性．

Predictive Spectrum Sensing Strategy Based on Reinforcement Learning

In this paper,we consider a cognitive radio(CR) system with a single secondary user(SU) and multiple licensed channels.The SU requests a fixed number of licensed channels and must sense the licensed channels one by one before transmission.By leveraging prediction based on correlation between the licensed channels,we propose a novel spectrum sensing strategy,to decide which channel is the best choice to sense in order to reduce the sensing time overhead and further improve the SU's achievable throughput.Since the correlation coefficients between the licensed channels cannot be exactly known in advance,the spectrum sensing strategy is designed based on the model-free reinforcement learning(RL).The experimental results show that the proposed spectrum sensing strategy based on reinforcement learning converges and outperforms random sensing strategy in terms of long-term statistics.

An Accelerated Iterative Method for Simultaneously Determining All Roots of Polynomial Equation

In this paper, an accelerated iteration method for simultaneously determining of a polynomial equation’s roots is proposed. The new method is an improvement of modified Newton method. At the same time, convergence properties and the order of convergence rate are discussed. At last, some numerical results are reported and listed.

Superlinear Convergence of a Smooth Approximation Method for Mathematical Programs with Nonlinear Complementarity Constraints

Mathematical programs with complementarity constraints(MPCC) is an important subclass of MPEC.It is a natural way to solve MPCC by constructing a suitable approximation of the primal problem.In this paper,we propose a new smoothing method for MPCC by using the aggregation technique.A new SQP algorithm for solving the MPCC problem is presented.At each iteration,the master direction is computed by solving a quadratic program,and the revised direction for avoiding the Maratos effect is generated by an explicit formula.As the non-degeneracy condition holds and the smoothing parameter tends to zero,the proposed SQP algorithm converges globally to an S-stationary point of the MPEC problem,its convergence rate is superlinear.Some preliminary numerical results are reported.

SUPERCONVERGENCE ANALYSIS OF A NONCONFORMING TRIANGULAR ELEMENT ON ANISOTROPIC MESHES

The class of anisotropic meshes we conceived abandons the regular assumption. Some distinct properties of Carey＇s element are used to deal with the superconvergence for a class of two- dimensional second-order elliptic boundary value problems on anisotropic meshes. The optimal results are obtained and numerical examples are given to confirm our theoretical analysis.

The Convergence of (r|~)_s(b_0h_n-h_1b_(n-1))

This paper computes the Thom map on γ2 and proves that it is represented by 2b2,0h1,2 in the ASS. The authors also compute the higher May differential of b2,0, from which it is proved that γ^～s（b0hn - h1bn-1） for 2 ≤ s 〈 p - 1 are permanent cycles in the ASS.

Asymptotic limit of the Gross-Pitaevskii equation with general initial data

This paper mainly concerns the mathematical justification of the asymptotic limit of the GrossPitaevskii equation with general initial data in the natural energy space over the whole space. We give a rigorous proof of the convergence of the velocity fields defined through the solutions of the Gross-Pitaevskii equation to the strong solution of the incompressible Euler equations. Furthermore, we also obtain the rates of the convergence.

Regularization Method and Immune Genetic Algorithm for Inverse Problems of Ship Maneuvering

Ship maneuverability, in the field of ship engineering, is often predicted by maneuvering motion group （MMG） mathematical model. Then it is necessary to determine hydrodynamic coefficients and interaction force coefficients of the model. Based on the data of free running model test, the problem for obtaining these coefficients is called inverse one. For the inverse problem, ill-posedness is inherent, nonlinearity and great computation happen, and the computation is also insensitive, unstable and time-consuming. In the paper, a regularization method is introduced to solve ill-posed problem and genetic algorithm is used for nonlinear motion of ship maneuvering. In addition, the immunity is applied to solve the prematurity, to promote the global searching ability and to increase the converging speed. The combination of regularization method and immune genetic algorithm（RIGA） applied in MMG mathematical model, showed rapid converging speed and good stability.

A Pinching Theorem for Riemannian Foliations with Parallel Mean Curvature in a Local-Symmetric Riemannian Manifold

We discuss the Riemannian foliations with parallel mean curvature in a local- symmetric Riemannian manifold,and obtain a pinching theorem about it.

A Unified Lorenz-Like System and Its Tracking Control

This paper introduces the finding of a unified Lorenz-like system.By gradually tuning the only parameter d,the reported system belongs to Lorenz-type system in the sense defined by Clikovsky.Meanwhile,this system belongs to Lorenz-type system,Lu-type system,Chen-type system with d less than,equivalent to and greater than 1.5,respectively,according to the classification defined by Yang.However,this system can only generate a succession of Lorenz-like attractors.Some basic dynamical properties of the system are investigated theoretically and numerically.Moreover,the tracking control of the system with exponential convergence rate is studied.Theoretical analysis and computer simulation show that the proposed scheme can allow us to drive the output variable x\ to arbitrary reference signals exponentially,and the guaranteed exponential convergence rate can be estimated accurately.