An approximate analytic solution of the nonlinear Riccati differential equation

In this paper, a hybrid method which combines the Adomian decomposition method (ADM), the Laplace transform algorithm and the Padé approximant is introduced to solve the approximate analytic solutions of the nonlinear Riccati differential equations. This hybrid method demonstrates accurate and reliable results, and has a great improvement in the ADM truncated series solution which diverges rapidly as the applicable domain increases. Three examples herein are given to demonstrate good accuracy and fast convergence in comparison with the exact solution.     

Variational iteration method for solving Fokker-Planck equation

In this paper variational iteration method is implemented to solve linear and nonlinear Fokker-Planck equations, and some similar equations. To illustrate the simplicity and reliability of the method some examples are provided and comparisons are made between the variational iteration method and the Adomian decomposition method. Comparison shows that variational iteration method is more effective and convenient to use and overcomes the difficulty arising in calculating Adomian polynomials. Also, this method can successfully be applied to a large class of problems.     

An efficient method for solving Emden–Fowler equations

In this paper, He's variational iteration method (VIM) is applied to solve the Emden–Fowler type equations in the second-order ordinary differential equations (ODEs). In this method, general Lagrange multipliers are introduced to construct correction functionals for the problems. The Lagrange multipliers in the functionals can be identified optimally via variational theory. This technique provides a sequence of functions which convergence to the exact solutions of the Emden–Fowler equations. Comparison with the exact solutions and the solutions by the Adomian decomposition method (ADM) show efficiency of VIM in solving equations with singularity.     

Pinning exponential synchronization for inertial coupled neural networks via adaptive aperiodically intermittent control under directed topology

This article is mainly focused on investigating pinning exponential synchronization of inertial coupled neural networks (ICNNs) under different directed topologies. The traditional method of variable substitution is removed and replaced by non-reduced order method to investigate the dynamical behavior of second-order coupled system. Additionally, by constructing Lyapunov-Krasovskii functional and utilizing matrix decomposition theory as well as M-matrix theory, an adaptive aperiodically intermittent controller is introduced to derive several improved sufficient criteria based on linear matrix inequalities (LMIs). Finally, some examples with numerical simulation are exhibited to confirm the availability of the theoretical results.     

Exponential synchronization of the switched uncertain neural networks with mixed delays based on sampled-data control

The synchronization for a class of switched uncertain neural networks (NNs) with mixed delays and sampled-data control is researched in this paper. When a switching signal occurs in a sampling interval, the controller cannot switch until the next sampling instant. There is a mismatch between the system and the controller. Thus, we devise the control strategy to guarantee that the switched NNs can be synchronized. The proposed Lyapunov-Krasovskii functional (LKF) can make full use of system information. By use of an improved integral inequality, some sufficient stability conditions formed by linear matrix inequalities (LMIs) are derived for the synchronization of switched NNs. Average dwell time (ADT) is obtained as a form of inequality that includes the sampling interval. At last, the feasibility of the proposed method is proved by some numerical examples.     

能源消费影响因素分解方法的比较研究

在能源消费研究中经常要将其变化分解为各种因素,通过各种因素的影响程度来分析影响能源消费的变化原因.自20世纪70年代以来,已经发展了多种分解方法,这些方法的假设前提与算法都有较大差异.本文从能源消费变化量与能源强度两个角度介绍了各种分解算法,对其进行了对比,并运用中国制造业的相关数据比较了分解的结果.能源消费变化量的分解方法中,Shapley算法与M-E算法分解结果相同,但是Shapley算法按照各因素的贡献加权来计算各因素对能源消费量的影响,更适合多因素分解;Se-Hark Park算法与AWT-PDM算法能较好地体现经济结构对能源消费量的影响,但AWT-PDM算法由于权数的确定问题,使得该算法存在不能分解的剩余项.能源强度变化的分解方法分为乘法分解和加法分解两大类,乘法分解反映的是能源强度变化率,加法分解反映的是能源强度变化量.Fisher算法与LMDI算法均是对能源强度的完全分解,而Laspeyres算法与AMDI算法均存在剩余项;方法是对AMDI算法的改进.研究者在研究能源问题或环境问题时,应根据研究要求及所掌握的数据选择恰当的分解方法.     

Exponentially admissibility of neutral singular systems with mixed interval time-varying delays

The chief aim of this paper is to analyze the exponentially admissibility of neutral singular systems (NSSs) with mixed interval time-varying delays (TVDs). A new Lyapunov-Krasovskii functional (LKF) is presented based on state decomposition method. Via adopting linear matrix inequality (LMI) method and zero-value equation technology, a novel delay-dependent exponentially admissibility criterion is acquired. Furthermore, the exponentially admissibility analysis of the NSSs with equal mixed TVDs is discussed. Three numerical examples show that our method is effective and superior. In particular, the reasonable analysis and design for two practical application models (direct current (DC) motor model and oil catalytic cracking process (OCCP) model) illustrate that our research is very meaningful.     

一种潮流计算的PQ改进算法研究

文章针对PQ分解法在导线截面较小（r〉x）的低压配电网络应用时存在不收敛的问题,根据B.Stott模型在PQ分解法的基础上提出采用由程序自动进行支路截断的改进PQ支路截断法,解决了r/x比值较高的电缆网络及更高的某些三绕组变压器网络的收敛性问题。并分别利用PQ法和改进的PQ支路截断法对7节点及11节点电力网络进行了仿真分析,实验结果验证了本方法的正确性和可行性,并且减少了迭代次数,加快了潮流计算的迭代速度,更有利于实时准确监测电网参数。     

A collocation method using Hermite polynomials for approximate solution of pantograph equations

In this paper, a numerical method based on polynomial approximation, using Hermite polynomial basis, to obtain the approximate solution of generalized pantograph equations with variable coefficients is presented. The technique we have used is an improved collocation method. Some numerical examples, which consist of initial conditions, are given to illustrate the reality and efficiency of the method. In addition, some numerical examples are presented to show the properties of the given method; the present method has been compared with other methods and the results are discussed.     

不确定时滞相关广义系统的H_∞鲁棒控制

针对不确定时滞相关广义系统的H∞鲁棒控制问题进行研究,目的是设计线性无记忆状态反馈控制器,使得对闭环系统所有的允许的不确定性正则、无脉冲、稳定且具有满意的H∞性能.将时滞相关广义系统的新有界实引理以严格的不等式线性矩阵方法给出,这些都是通过引入新的Lyapunov-Krasovskii泛函,使用詹森不等式得出的.其次,在新的有界实引理的基础上给出了(不确定)时滞相关广义系统的(鲁棒)控制器存在的充分条件.所得出的结果都以严格的线性矩阵不等式形式表示并且都是时滞相关的,未涉及系统矩阵的分解.最后,通过数值算例说明了该方法具有较小的保守性和有效性.     

环境约束下长江经济带工业能源环境效率差异评价与成因识别研究

首先用融合径向与非径向距离函数特征的EBM方法测度了环境约束下长江经济带9省2市的工业能源环境效率,借助效率核密度图和技术分解分析了效率随时间的演变趋势和空间差异；继而利用泰尔熵量化区域工业能源环境效率的总体差距,并将其分解结果运用于地区差异的成因识别中。研究结果显示：长江经济带工业能源环境效率普遍偏低,在经历短暂的上升期后,近年来持续走低,规模效率下降是主要原因；研究期内区域工业能源环境效率的总体差距逐渐缩小,区域间差距仍为驱动总体差距的主导因素,缩小上游区域内差距显得尤为重要。     

三维电大尺寸介质目标电磁散射特性的特征基函数法分析

特征基函数法是近几年提出的一种求解电磁散射问题的有效方法,该方法基于分块和高层基函数的概念,通过对子域大小的选择来控制生成矩阵的维数,是一种新颖的矩阵降阶方法。应用特征基函数并结合区域分解法对三维电大尺寸介质柱的远区散射场进行了计算,通过扩展子域边界的办法来消除直接划分子域所带来的电流不连续性问题。结果与传统矩量法的计算结果吻合良好,而计算效率得到较大的提高。     

同一岩石试样的Lu-Hf和Sm-Nd快速分离及国家岩石标准物质的Hf-Nd同位素比值精确测定

本文报道基于Li2B4O7熔融样品、采用AG50W-X8和HDEHP组合或RE和HDEHP组合色谱交换柱,对同一岩石试样快速分离Sm-Nd-Lu-Hf的方法。用这两种方法对国际岩石标准BHVO-2、GSP-2和JB-1进行了Lu-Hf、Sm-Nd分离和^143 Nd/^144 Nd、^176Hf/^177Hf测定,并测定了BHVO-2、JB-1和JB-3的Lu/Hf和Sm/Nd比值,获得的结果在误差范围内与这些样品的参考值一致.同时,我们对国家岩石标准物质GBW07109、GBW07110和GBW07113进行了多次平行分析,首次获得了这些岩石标准的Nd-Hf同位素结果.     

Quadratic stability analysis and robust distributed controllers design for uncertain spatially interconnected systems

This paper is concerned with the quadratic stability analysis and robust distributed controllers design of both continuous-time and discrete-time uncertain spatially interconnected systems (USISs), where uncertainties are modeled by linear fractional transformation (LFT). The well-posedness, quadratic stability, and contractiveness of USISs are properly defined for the first time. A sufficient condition employing the given system matrices is established to check the well-posedness, quadratic stability and contractiveness. This condition is simpler than the existing conditions based on the decomposition of system matrices. Based on the new condition derived, a sufficient condition is given for the existence of robust distributed controllers and a constructive method is then presented for the design of robust distributed controllers. The advantage of the proposed constructive approach is that it employs the given system matrices while the existing methods conduct the bilinear transformation on these matrices when design controllers, and consequently, the constructive approach in this paper is computationally more efficient than the existing methods. Several examples are included to demonstrate the simplicity, efficiency and applicability of the derived theoretical results.     

Stability and stabilization for switched positive systems under a weighted MDADT method

The stability and stabilization synthesis problems of the switched positive systems (SPSs) with external disturbances are studied in this paper. For the studied SPSs, a weighted mode-dependent average dwell time (WMDADT) switched strategy has been adopted to analyze the above-mentioned issue, based on which the deficiencies of the existing ADT and MDADT switching techniques can be overcomed. By using the adopted strategy, some improved stability conditions that have less conservativeness are presented for the systems under investigation. Moreover, based on the developed stability conditions, an efficient controller design method avoiding computational complexity and eliminating the rank requirement of the controller is presented. In the end, the effectiveness of the method is verified by two numerical examples.     

Physical parameter sensitivity of system eigenvalues and physical model reduction

The identification of subsystems and/or components that is related to a given eigenvalue of the overall system is a challenging and important topic. The use of special structure of the system matrices obtained busing bond graphs can result in identifying subsystems and/or components that affect a given eigenvalue of an overall system. This paper, by making use of a set of theorems and definitions proposes an efficient procedure for this purpose. The basic procedure is based upon the calculation of sensitivity of eigenvalues. The so-called “effect” matrices are produced that indicates the relative importance of physical parameters on a selected eigenvalue. In addition to the relative importance, the effect matrix is used for an efficient physical model reduction procedure. Furthermore, reasons of different dynamic behavior of a system can be explained. Use of effect matrices also improves the physical model reduction method based on decomposition procedures. Three examples are given to illustrate the approach and its consequences.     

Modified tracking performance limitation of networked time-delay systems with two-channel constraints

This paper investigates the modified tracking performance limitation of the networked time-delay systems with two-channel constraints. We consider both the white Gaussian noise and packet dropout constraints in the communication channels. In the plant, the non-minimum phase, unstable poles and time-delay are considered. The modified tracking performance limitation expressions will be achieved using the co-prime factorization and the spectral decomposition technique, and the two-parameter controller is adopted. The results show that the modified tracking performance limitation is related to the intrinsic properties of the given plant, including the non-minimum phase zeroes, the unstable poles and the time-delay. Furthermore, the network communication parameters, e.g. the white Gaussian noise, the packet-dropouts probability and the modified factor affect the modified tracking performance limitation of the networked time-delay systems. Finally, some particular examples are provided to illustrate the efficiency of the proposed method.     

改进最大熵算法重建日像仪太阳图像

日像仪太阳图像重建是获取高分辨率图像最后也是最重要的途径。为加快收敛速度而提出的Skilling-Bryan最大熵算法是天文图像处理主流算法之一。通过对SB算法在搜索方向上的改进，使原算法由于近似而产生较大误差时可以自动得到校正，达到了快速与准确的和谐统一。最后，利用两种算法对中科院国家天文台拟建的日像仪进行了仿真，结果显示，改进算法的重建图像分辨率得到明显提高而时间效率与原有算法相当。大量仿真则证明了算法收敛的稳定性。     

基于改进的Canny算子图像信息提取算法研究

研究文本定位与特征提取问题。针对传统的Canny算子图像检测算法的不足,提出了一种改进的Canny算子图像信息特征提取算法。研究方法是:首先对彩色图像进行高斯金字塔分解,然后用Canny算子检测彩色图像,提取边缘图像,再经过通二值化,去噪方差投影定位文本区域。实验结果表明,本文提出的方法有效、实用。     

企业专利质量优劣评价的犹豫模糊平衡参考解方法

为促进提高创新专利质量,更好地服务于企业创新工作,提出一种基于犹豫模糊平衡参考解的专利评价方法.考虑到专利质量评价需多群组参与的实际情况以及评价问题本身的模糊性,将犹豫模糊集作为评价信息载体;鉴于人类评价事物时热衷于列出优劣势项的习惯,借助TOPSIS和EDAS参考解思想,构造一种平衡参考解的集成模型;此外,考虑到传统距离测度无法在同一水平直接衡量具有差异性的数据,构建一种基于Bray-Curtis距离的犹豫模糊测度方法;最后,以W企业的四类专利质量评价为实例以验证该方法的可行性,为企业的专利质量评价提供新思路与技术支撑.