An Algorithm for Short-Circuit Current Interval in Distribution Networks with Inverter Type Distributed Generation Based on Affine Arithmetic

During faults in a distribution network,the output power of a distributed generation(DG)may be uncertain.Moreover,the output currents of distributed power sources are also affected by the output power,resulting in uncertainties in the calculation of the short-circuit current at the time of a fault.Additionally,the impacts of such uncertainties around short-circuit currents will increase with the increase of distributed power sources.Thus,it is very important to develop a method for calculating the short-circuit current while considering the uncertainties in a distribution network.In this study,an affine arithmetic algorithm for calculating short-circuit current intervals in distribution networks with distributed power sources while considering power fluctuations is presented.The proposed algorithm includes two stages.In the first stage,normal operations are considered to establish a conservative interval affine optimization model of injection currents in distributed power sources.Constrained by the fluctuation range of distributed generation power at the moment of fault occurrence,the model can then be used to solve for the fluctuation range of injected current amplitudes in distributed power sources.The second stage is implemented after a malfunction occurs.In this stage,an affine optimization model is first established.This model is developed to characterizes the short-circuit current interval of a transmission line,and is constrained by the fluctuation range of the injected current amplitude of DG during normal operations.Finally,the range of the short-circuit current amplitudes of distribution network lines after a short-circuit fault occurs is predicted.The algorithm proposed in this article obtains an interval range containing accurate results through interval operation.Compared with traditional point value calculation methods,interval calculation methods can provide more reliable analysis and calculation results.The range of short-circuit current amplitude obtained by this algorithm is slightly larger than those obtained using the Monte Carlo algorithm and the Latin hypercube sampling algorithm.Therefore,the proposed algorithm has good suitability and does not require iterative calculations,resulting in a significant improvement in computational speed compared to the Monte Carlo algorithm and the Latin hypercube sampling algorithm.Furthermore,the proposed algorithm can provide more reliable analysis and calculation results,improving the safety and stability of power systems.

A Remark on the Affine Coordinates for KdV Tau-Functions

We give a proof of an explicit formula for affine coodinates of points in the Sato’s infinite Grassmannian corresponding to tau-functions for the KdV hierarchy.

Heteroclinic Cycles in a Class of 3-Dimensional Piecewise Affine Systems

This paper explores the existence of heteroclinic cycles and corresponding chaotic dynamics in a class of 3-dimensional two-zone piecewise affine systems. Moreover, the heteroclinic cycles connect two saddle foci and intersect the switching manifold at two points and the switching manifold is composed of two perpendicular planes.

可用于相关亚历山大藻(Alexandrium affine)检测的一个寡核苷酸探针

针对分离自南海的相关亚历山大藻,在进行核糖体大亚基DNA(LSU rDNA)全序列测序及比对的基础上,设计了针对其核糖体大亚基RNA(LSU rRNA)D10区的一个新的荧光素(FITC)标记寡核苷酸探针,并建立了相应的荧光原位杂交检测方法。在GenBank数据库中,BLAST检索的结果显示所设计的探针具有较高的特异性。杂交实验的结果也表明,这条探针对相关亚历山大藻的标记具有特异性,且标记效率可以达到100%,标记信号清晰明亮。本研究结果为相关亚历山大藻的监测及其种群动态研究提供了方法学依据,也为其它微藻特异性探针的设计提供了新的思路。

基于Harris-Affine和SIFT特征匹配的图像自动配准

针对大失配多传感器图像,提出了一种基于SIFT(scale invariant keypoints)和Harris-Affine(H-A)互补不变特征匹配的自动配准算法.算法应用SIFT和H-A两种具有互补特性的局部不变特征,根据最近邻特征点距离与次近邻特征点距离之比确定初始匹配点对,然后利用马氏距离的仿射不变性删除误匹配特征点对,据此求取2幅源图像间的仿射变换参数.使用估计的变换矩阵把待配准图像上的所有点映射到参考图像,并对其进行重采样,实现图像的配准.实验结果表明:该算法能够快速高精度实现大失配图像的自动配准.

基于Harris-Affine的宽基线立体影像LSM匹配方法

针对宽基线影像的高畸变特点,提出基于几何一致性约束的Harris-Affine高精度最小二乘匹配(Least Square Matching,LSM)方法。首先,用Harris-Affine算子在影像高斯多尺度空间中提取仿射不变特征,并根据特征区域灰度矩阵与主梯度方位来实现特征的几何归一化,继而提取特征描述符,接着采用一种由粗到精的特征匹配策略来渐进地获取正确率占优的特征匹配。然后,通过LSM迭代方法来补偿同名像点的定位误差,LSM迭代所需的良好的几何畸变初值由同名特征区域灰度矩阵与主梯度方位求取,而良好的辐射畸变初值通过同名区域像元灰度的最小二乘线性拟合法求取。实验结果表明:该算法鲁棒有效,且实现了亚像素匹配精度。

Stability analysis for affine fuzzy system based on fuzzy Lyapunov functions

An analysis method based on the fuzzy Lyapunov functions is presented to analyze the stability of the continuous affine fuzzy systems. First, a method is introduced to deal with the consequent part of the fuzzy local model. Thus, the stability analysis method of the homogeneous fuzzy system can be used for reference. Stability conditions are derived in terms of linear matrix inequalities based on the fuzzy Lyapunov functions and the modified common Lyapunov functions, respectively. The results demonstrate that the stability result based on the fuzzy Lyapunov functions is less conservative than that based on the modified common Lyapunov functions via numerical examples. Compared with the method which does not expand the consequent part, the proposed method is simpler but its feasible region is reduced. Finally, in order to expand the application of the fuzzy Lyapunov functions, the piecewise fuzzy Lyapunov function is proposed, which can be used to analyze the stability for triangular or trapezoidal membership functions and obtain the stability conditions. A numerical example validates the effectiveness of the proposed approach.

基于Affine强度的一般Poisson损失动态模型

首先介绍了GPL动态模型,然后引入Affine过程的概念,讨论随机强度是Affine过程时的GPL模型,并进一步讨论了如何求出随机过程的损失密度,从而得出CDO债券的价格.

相关亚历山大藻(Alexandrium affine)(非PSP产毒株)毒理的初步研究

采用生物急性毒性实验的方法,对一株不产PSP毒素的相关亚历山大藻(Alexandrium affine,株AC-1)的毒性及其毒素(AFT)成分进行研究。结果表明,相关亚历山大藻(AC-1)对卤虫、轮虫、糠虾均有毒性效应,其96hLC50分别为:90cells/ml,1500cells/ml,5000cells/ml。相关亚历山大藻(AC-1)各组分:藻液、细胞重悬液、藻细胞培养过滤液、内容物对卤虫存活率均有显著影响,表明AFT毒素可能来源于细胞内,能分泌到细胞培养液中。通过对该藻过滤液的热稳定性、酸碱稳定性、去蛋白组分毒性、分子量范围、极性、多糖组分鉴定,表明AFT毒素为极性较强的多糖类物质,对热和酸碱稳定,其分子量范围为5—50kDa。

Inhibition of Xanthine Oxidase Activity by Gnaphalium Affine Extract

Objective To evaluate the inhibitory effect of Gnaphalium affine extracts on xanthine oxidase(XO) activity in vitro and to analyze the mechanism of this effect. Methods In this in vitro study, Kinetic measurements were performed in 4 different inhibitor concentrations and 5 different xanthine concentrations(60, 100, 200, 300, 400 μmol/L). Dixon and Lineweaver-Burk plot analysis were used to determine Ki values and the inhibition mode for the compounds isolated from Gnaphalium affine extract. Results Four potent xanthine oxidase inhibitors were found in 95% ethanolic(v/v) Gnaphalium affine extract. Among them, the f lavone Eupatilin exhibited the strongest inhibitory effect on XO with a inhibition constant(Ki) of 0.37 μmol/L, lower than the Ki of allopurinol(4.56 mol/L), a known synthetic XO inhibitor. Apigenin(Ki of 0.56 μmol/L, a proportion of 0.0053‰ in Gnaphalium affine), luteolin(Ki of 2.63 μmol/L, 0.0032‰ in Gnaphalium affine) and 5-hydroxy-6,7,3',4'-tetramethoxyflavone(Ki of 3.15 μmol/L, 0.0043‰ in Gnaphalium affine) also contributed to the inhibitory effect of Gnaphalium affine extract on XO activity. Conclusions These results suggest that the use of Gnaphalium affine in the treatment of gout could be attributed to its inhibitory effect on XO. This study provides a rational basis for the traditional use of Gnaphalium affine against gout.

A Correntropy-based Affine Iterative Closest Point Algorithm for Robust Point Set Registration

The iterative closest point(ICP)algorithm has the advantages of high accuracy and fast speed for point set registration,but it performs poorly when the point set has a large number of noisy outliers.To solve this problem,we propose a new affine registration algorithm based on correntropy which works well in the affine registration of point sets with outliers.Firstly,we substitute the traditional measure of least squares with a maximum correntropy criterion to build a new registration model,which can avoid the influence of outliers.To maximize the objective function,we then propose a robust affine ICP algorithm.At each iteration of this new algorithm,we set up the index mapping of two point sets according to the known transformation,and then compute the closed-form solution of the new transformation according to the known index mapping.Similar to the traditional ICP algorithm,our algorithm converges to a local maximum monotonously for any given initial value.Finally,the robustness and high efficiency of affine ICP algorithm based on correntropy are demonstrated by 2D and 3D point set registration experiments.

LMI-based robust control of uncertain discrete-time piecewise affine systems

The main contribution of this paper is to present stability synthesis results for discrete-time piecewise affine （PWA） systems with polytopic time-varying uncertainties and for discrete-time PWA systems with norm-bounded uncertainties respectively.The basic idea of the proposed approaches is to construct piecewise-quadratic （PWQ） Lyapunov functions to guarantee the stability of the closed-loop systems.The partition information of the PWA systems is taken into account and each polytopic operating region is outer approximated by an ellipsoid,then sufficient conditions for the robust stabilization are derived and expressed as a set of linear matrix inequalities （LMIs）.Two examples are given to illustrate the proposed theoretical results.

THE GRAPH INDUCED BY AFFINE M-FLATS OVER FINITE FIELDS II

Let AG(n,F q) be the n-dimensional affine space over F q,where F q is a finite field with q elements.Denote by Γ (m) the graph induced by m-flats of AG(n,F q).For any two adjacent vertices E and F of Γ (m),Γ (m)(E)∩Γ (m)(F) is studied.In particular,sizes of maximal cliques in Γ (m) are determined and it is shown that Γ (m) is not edge-regular when m<n-1.

Using Affine Quantization to Analyze Non-Renormalizable Scalar Fields and the Quantization of Einstein’s Gravity

Affine quantization is a parallel procedure to canonical quantization, which is ideally suited to deal with non-renormalizable scalar models as well as quantum gravity. The basic applications of this approach lead to the common goals of any quantization, such as Schroedinger’s representation and Schroedinger’s equation. Careful attention is paid toward seeking favored classical variables, which are those that should be promoted to the principal quantum operators. This effort leads toward classical variables that have a constant positive, zero, or negative curvature, which typically characterize such favored variables. This focus leans heavily toward affine variables with a constant negative curvature, which leads to a surprisingly accommodating analysis of non-renormalizable scalar models as well as Einstein’s general relativity.

Constrained sliding mode control of nonlinear fractional order input affine systems

Asymptotic stability of nonlinear fractional order affine systems with bounded inputs is dealt.The main contribution is to design a new bounded fractional order chattering free sliding mode controller in which the system states converge to the sliding surface at a determined finite time.To eliminate the chattering in the sliding mode and make the input controller bounded,hyperbolic tangent is used for designing the proposed fractional order sliding surface.Finally,the stability of the closed loop system using this bounded sliding mode controller is guaranteed by Lyapunov theory.A comparison with the integer order case is then presented and fractional order nonlinear polynomial systems are also studied as the special case.Finally,simulation results are provided to show the effectiveness of the designed controller.

The Benefits of Affine Quantization

Canonical quantization has served wonderfully for the quantization of a vast number of classical systems. That includes single classical variables, such as p and q, and numerous classical Hamiltonians H(p,q), as well as field theories, such as π(x) and φ(x), and many classical Hamiltonians H(π,φ. However, in all such systems, there are situations for which canonical quantization fails. This includes certain particle and field theory problems. Affine quantization involves a simple recombination of classical variables that lead to a new chapter in the process of quantization, and which is able to solve a vast variety of normally insoluble systems, such as quartic interactions in scalar field theory in spacetime dimensions 4 and higher, as well as the quantization of Einstein’s gravity in 4 spacetime dimensions.

POLYNOMIAL REPRESENTATIONS OF THE AFFINE NAPPI-WITTEN LIE ALGEBRA H_4

In this paper, the representation theory for the arlene Lie algebra H4 associated to the Nappi-Witten Lie algebra H4 is studied. Polynomial representations of the affine Nappi-Witten Lie algebra H4 are given.

Image-Moment Based Affine Invariant Watermarking Scheme Utilizing Neural Networks

A new image watermarking scheme is proposed to resist rotation, scaling and translation （RST） attacks. Six combined low order image moments are utilized to represent image information on rotation, scaling and translation. Affine transform parameters are registered by feedforward neural networks. Watermark is adaptively embedded in discrete wavelet transform （DWT） domain while watermark extraction is carried out without original image after attacked watermarked image has been synchronized by making inverse transform through parameters learned by neural networks. Experimental results show that the proposed scheme can effectively register affine transform parameters, embed watermark more robustly and resist geometric attacks as well as JPEG2000 compression.

A SUFFICIENT CONDITION FOR AFFINE FRAMES WITH MATRIX DILATION

A sufficient condition for affine frame with an arbitrary matrix dilation is presented. It is based on the univariate case by Shi, and generalizes the univariate results of Shi, Casazza and Christensen from one dimension with an arbitrary real number a （a 〉 1） dilation to higher dimension with an arbitrary expansive matrix dilation.

Realization of Fractal Affine Transformation

This paper gives the definition of fractal affine transformation and presents a specific method for its realization and its corresponding mathematical equations which are essential in fractal image construction.