Near-Vector Spaces Constructed over Zp, for p a Prime

The purpose of this paper is to construct near-vector spaces using a result by Van der Walt, with Zp for p a prime, as the underlying near-field. There are two notions of near-vector spaces, we focus on those studied by André [1]. These near-vector spaces have recently proven to be very useful in finite linear games. We will discuss the construction and properties, give examples of these near-vector spaces and give its application in finite linear games.

EMBEDDING THEOREMS ON CAMPANATO-MORREY SPACES FOR VECTOR FIELDS OF HoRMANDER TYPE

This paper deals with embedding theorems on Campanato-Marrey spaces formed by degenerate vector fields, which include Honnander and Grushin type of vector fields. These embedding theorems are somewhat different from the known Poincare estimates. The main ingredients of the proofs rely on the fractional maximal functions. These results evidently have applications to the regularity of subelliptic PDE.

On a Hypothetical Vector Field Associated with the Classic Electromagnetic Wave in a Space of Four Dimensions

In two previous papers [1] and [2], a structure for vector products in n dimensions was presented, and at the same time it was possible to propose the existence of a vector analogous to the curl of a vector field, for a space of four dimensions. In continuation of these works, the objective is to develop, through dimensional analogy, the idea of a hypothetical vector field, associated with the classical electromagnetic wave. This hypothetical field has a possible mathematical existence only when considering a space of four dimensions. The properties of the electromagnetic wave are preserved and equations with mathematical forms analogous to those of Maxwell’s equations are presented.

On the Massless Vector Fields in a Rindler Space

We study the quantum theory of the mass-less vector fields on the Rindler space. We evaluate the Bogoliubov coefficients by means of a new technique based upon the use of light-front coordinates and Mellin transform. We briefly comment about the ensuing Unruh effect and its consequences.

Construction of PBIB Desings by Using Subspace of Vector Space over Finite Fields

A new transitivity theorem of the general linear group GLn(Fq)is proved. A kind of new PBIB desings is constructed.

Concircular π-Vector Fields and Special Finsler Spaces

The aim of the present paper is to investigate intrinsically the notion of a concircular π-vector field in Finsler geometry. This generalizes the concept of a concircular vector field in Riemannian geometry and the concept of concurrent vector field in Finsler geometry. Some properties of concircular π-vector fields are obtained. Different types of recurrence are discussed. The effect of the existence of a concircular π-vector field on some important special Finsler spaces is investigated. Almost all results obtained in this work are formulated in a coordinate-free form.

A Simple Proof for a Property of the Vector Space Ⅴ Over the Field F

In this paper we’ll prove a fundameutal property of the vector space by means of the ex-tension field,i.e.the numbers of the elements of a basis of the vector space V over the field Fequal to the d imensions(V:F).

DECOMPOSITION OF BV FUNCTIONS IN CARNOT-CARATHEODORY SPACES

The aim of this paper is to get the decomposition of distributional derivatives of functions with bounded variation in the framework of Carnot-Caratheodory spaces (C-C spaces in brievity) in which the vector fields are of Carnot type. For this purpose the approximate continuity of BV functions is discussed first, then approximate differentials of L1 functions are defined in the case that vector fields are of Carnot type and finally the decomposition Xu = (?)u ·Ln + X2 u is proved, where u ∈ BVx(?) and (Ω)u denotes the approximate differential of u.

<i>L_p</i>-Estimations of Vector Fields in Unbounded Domains

Some new estimations of scalar products of vector fields in unbounded domains are investigated. Lp-estimations for the vector fields were proved in special weighted functional spaces. The paper generalizes our earlier results for bounded domains. Estimations for scalar products make it possible to investigate wide classes of mathematical physics problems in physically inhomogeneous domains. Such estimations allow studying issues of correctness for problems with non-smooth coefficients. The paper analyses solvability of stationary set of Maxwell equations in inhomogeneous unbounded domains based on the proved Lp-estimations.

多机器人协同路径的时域协作-势场A*规划

为了减小多机器人协同工作路径长度并提高路径平滑度,提出了基于时域协作-势场A*算法的多机器人协同规划方法。建立了机器人工作环境的栅格模型,分析了传统A*算法辅助信息不充分的问题。为了充分利用环境中的障碍物和目标点位置等先验信息,基于势场法将障碍物和目标点信息引入到A*算法辅助信息中,提出了基于势场A*算法的单机器人路径规划方法。使用三维时空图代替二维平面图,可以有效判断出多机器人碰撞问题,并根据碰撞类型制定了避撞策略。经验证,势场A*算法规划的路径长度和平滑度均优于传统A*算法、文献[11]蚁群算法;在多机器人协同路径规划中,在规划出各机器人最优路径基础上,可以有效解决机器人之间的碰撞问题。实验结果验证了时域协作-势场A*算法在多机器人协同路径规划中的有效性和优越性。

A Construction of Authentication Codes with Arbitration from Vector Spaces over Finite Fields

This paper is devoted to constructing an authentication code with arbitration using subspaces of vector spaces over finite fields.Moreover,if we choose the encoding rules of the transmitter and the decoding rules of the receiver according to a uniform probability distribution,then some parameters and the probabilities of successful attacks are computed.

Poincaré and Sobolev Inequalities for Vector Fields Satisfying Hrmander's Condition in Variable Exponent Sobolev Spaces

In this paper, we will establish Poincare inequalities in variable exponent non-isotropic Sobolev spaces. The crucial part is that we prove the boundedness of the fractional integral operator on variable exponent Lebesgue spaces on spaces of homogeneous type. We obtain the first order Poincare inequalities for vector fields satisfying Hormander＇s condition in variable non-isotropic Sobolev spaces. We also set up the higher order Poincare inequalities with variable exponents on stratified Lie groups. Moreover, we get the Sobolev inequalities in variable exponent Sobolev spaces on whole stratified Lie groups. These inequalities are important and basic tools in studying nonlinear subelliptic PDEs with variable exponents such as the p（x）-subLaplacian. Our results are only stated and proved for vector fields satisfying Hormander＇s condition, but they also hold for Grushin vector fields as well with obvious modifications.

Flows Associated to Cameron-martin Type Vector Fields on Path Spaces Over a Riemannian Manifold

The flow on the Wiener space associated to a tangent process constructed by Cipriano and Cruzeiro, as well as by Gong and Zhang does not allow to recover Driver’s Cameron-Martin theorem on Riemannian path space. The purpose of this work is to refine the method of the modified Picard iteration used in the previous work by Gong and Zhang and to try to recapture and extend the result of Driver. In this paper, we establish the existence and uniqueness of a flow associated to a Cameron-Martin type vector field on the path space over a Riemannian manifold.

SVPWM逆变器供电时FSCW-PMSM损耗特性研究

为探究空间矢量脉宽调制(space vector pulse width modulation,SVPWM)逆变器引入的时间谐波电流对分数槽集中绕组永磁同步电机(fractional-slot concentrated-winding permanent magnet synchronous machine,FSCW-PMSM)损耗特性的影响,文中提出一种SVPWM逆变器与FSCW-PMSM联合系统中电机损耗谐波特性分析方法。首先,理论分析了考虑时间谐波电流时电机损耗的时空谐波特性。其次,以一台三相双层绕组10极12槽PMSM为例,搭建电机与SVPWM逆变器的场路联合仿真模型,求解样机在恒转矩和恒功率调速时损耗的谐波特性,揭示各谐波损耗的产生机理。结果表明:转子谐波损耗由基波电流与次谐波、iZ±p次齿谐波和(f_(c)±4 f)/f、(f_(c)±2 f)/f次时间谐波电流与p、Z±p次空间谐波引起;定子铁芯谐波损耗由基波磁场、谐波励磁磁场及(f_(c)±4 f)/f、(f_(c)±2 f)/f次时间谐波电流引起。该结论适用于其他极槽组合的FSCW-PMSM。最后,通过实验验证了该分析方法的有效性。

基于磁场传感器磁成像装置研究

针对空间磁场矢量分布情况,给出一种空间磁场测量和成像的装置,主要由磁场矢量传感器、三维移动平台和信号处理电路等部分构成。在待测磁场空间中,通过三维移动平台调整磁场矢量传感器的测量位置,然后利用传感器测量相应位置处的磁场分量(Bx、By和Bz),采用信号处理电路并行对传感器的输出电压进行放大、滤波、调零和A/D转换等处理。在微控制器进行数字滤波和数据传输后,利用软件分析和处理获取的数据,并绘制空间磁场矢量分布图。实验结果表明在一定待测磁场范围内,该磁成像装置能够实现永磁铁附近的空间磁场相应位置的磁场矢量测量,并形成磁场分布图,该装置可以对-1000 Gs~+1000 Gs的磁场进行测量,磁场分辨率为2 Gs,空间分辨率为3 mm3。

基于虚拟电压矢量的磁场定向控制策略研究

针对双三相永磁同步电机(PMSM)矢量控制系统中定子相电流的谐波问题,在采用传统两矢量空间矢量脉宽调制算法的基础上,提出基于最大四矢量的空间矢量脉宽调制算法的磁场定向控制策略。其次,针对最大四矢量的空间矢量脉宽调制算法计算量大,设计复杂的问题,又提出了基于虚拟电压矢量的空间矢量脉宽调制算法的改进型磁场定向控制策略。最后,通过MATLAB/Simulink仿真平台,验证所提出的改进型控制算法策略的有效性。

基于空间向量分解的边界剥离密度聚类

作为聚类的重要组成部分,边界点在引导聚类收敛和提升模式识别能力方面起着重要作用,以BP(Border-peeling clustering)为最新代表的边界剥离聚类借助潜在边界信息来确保簇核心区域的空间隔离,提高了簇骨架代表性并解决了边界隶属问题.然而,现有边界剥离聚类仍存在判别特征不完备、判别模式单一、嵌套迭代等约束.为此,提出了基于空间向量分解的边界剥离密度聚类(Density clustering based on the border-peeling using space vector decomposition,CBPVD),以投影子空间和原始数据空间为基准,从分布稀疏性(紧密性)和方向偏斜性(对称性)两个视角强化边界的细粒度特征,进而通过主动边界剥离反向建立簇骨架并指导边界隶属.与同类算法相比,40个数据集(人工、UCI、视频图像)上的实验结果以及4个视角的理论分析表明了CBPVD在高维聚类和边界模式识别方面具有良好的综合表现.

基于磁场定向控制的直线电机控制系统研究

文章主要分析和研究永磁同步直线电机(Permanent Magnet Linear Synchronous Motor,PMLSM)的驱动控制系统。首先,建立直线电机在ABC坐标系和dq坐标系下的数学模型。其次,在dq坐标系下实现直交轴解耦,采用磁场定向控制的策略控制PMLSM,采用i_(d)=0的控制方式,并利用空间脉宽矢量调制方法调制驱动。最后,搭建PMLSM控制系统,采用速度、推力双闭环控制实现PMLSM的精确定速,同时保证其推力满足要求。

SVM-KNN分类器——一种提高SVM分类精度的新方法

本文提出了一种将支持向量机分类和最近邻分类相结合的方法 ,形成了一种新的分类器 .首先对支持向量机进行分析可以看出它作为分类器实际相当于每类只选一个代表点的最近邻分类器 ,同时在对支持向量机分类时出错样本点的分布进行研究的基础上 ,在分类阶段计算待识别样本和最优分类超平面的距离 ,如果距离差大于给定阈值直接应用支持向量机分类 ,否则代入以每类的所有的支持向量作为代表点的K近邻分类 .数值实验证明了使用支持向量机结合最近邻分类的分类器分类比单独使用支持向量机分类具有更高的分类准确率 。

基于混沌支持向量机的河川径流预测研究

以黄河上游兰州站月径流序列为研究对象,在介绍相空间重构原理的基础上,探讨了混沌分析的主要定量指标：饱和关联维数d,最大Lyapunov指数λ和Kolmogorov熵k。得到该时间序列的最佳嵌入滞时τ=3个月,饱和关联维数d=3.230,最小嵌入维数m=12和最大Lyapunov指数λ=0.241,Kolmogorov熵k=0.14,指出该序列的预测时限为4个月。在此基础上建立了基于混沌特性的支持向量机径流预测模型,用1995-2004年的月径流数据进行仿真试验后,用2005年1-12月的径流数据作为预测检验,结果表明,该模型可用于混沌时间序列的月径流预测,并验证了由最大Lyapunov指数所确定的可预报时限为4个月的结论。