基于改进型自调整轴系幅值收敛电流解调算法的旋转高频电压注入法

应用于旋转高频电压注入法的自调整轴系幅值收敛(SFAC)电流解调算法简单实用,可实现静止工况下永磁同步电机转子初始位置高精度辨识。但分析发现,由于位置估计误差随转速变化而变化,该算法不适用于非零速区间。为此,提出一种改进型SFAC(ISFAC)电流解调算法。该算法在估计dq坐标系下对高频电流解调并构造转子位置误差信号,利用正序、负序高频电流相移等值异号的特性实现电流相移自动抵消,不仅省去复杂的位置误差补偿策略,而且将原SFAC算法的速度适用范围由零速区拓宽至非零速区。该文对SFAC算法的原理以及导致非零速区位置估计误差的原因进行分析,并介绍ISFAC算法的实现过程。最后利用RT-Lab平台对传统SFAC算法与ISFAC算法的位置估计性能进行对比验证。

空间C[0,1]的一个新的Schauder基

引入了区间［０，１］上一个新的标准正交系｛ｇａｌｋ（ｔ）｝∞０，证明了它在［０，１］上是一致有界的且是空间Ｃ［０，１］的Ｓｃｈａｕｄｅｒ基，同时｛ｇａｌｋ（ｔ）｝∞０的Ｌｅｂｅｓｇｕｅ函数｛Ｌ（Ｇ）ｎ（ｔ）｝在［０，１］上也是一致有界的，且｛ｇａｌｋ（ｔ）｝∞０还是［０，１］上的一个收敛系。

基于旋转高频注入的内置式永磁同步电机初始位置检测算法

旋转高频电压注入法检测内置式永磁同步电机(IPMSM)初始位置时,针对信号滤波和数字控制延时会增大检测误差的问题,提出基于自调整轴系幅值收敛(SFAC)的位置信号解调算法。首先,将电流变换到两相自调整轴系中,变换角度为磁极位置估计角度+π/4,从而无需补偿数字控制延时造成的相位偏差。其次,采用递推离散傅里叶变换(DFT)计算两相自调整轴系的电流幅值,其幅值二次方差经过锁相环输出的磁极位置估计角度,再结合电压脉冲注入法判断磁极极性。其信号解调过程无需滤波处理,从而避免了滤波器的相移问题。最后,将所提的SFAC算法与同步轴系高通滤波器(SFHF)算法进行对比分析,并通过实验验证了算法的正确性和优越性。

THE FORMATION AND DEVELOPMENT OF A MESOSCALE CONVECTIVE SYSTEM WITH HEAVY RAINFALL ALONG SOUTH CHINA COASTAL AREA

Observational analysis shows that a Mesoscale Convective System (MCS) occurred on May 13-14 2004 along the coastal area in South China. The MCS initiated among the southwesterly flows within a west-east orientation low-level shear line. Associated with the system, in its subsequent development stages, no distinct vortex circulation developed in low-level. Instead, a cyclonic flow disturbance was observed in the mid-troposphere. How the convection starts to develop and evolve into a MCS With observational analysis and numerical simulation, the problem has been studied. The high-resolution MM5 simulation shows that topographic convergence along the coastal line and the nearby mountains in western South China plays an important role to initiate the MCS convection. Once the convection occurs, due to the condensation heating, a cooperative interaction between the preexisting mid-level disturbance and convection is created, which may greatly affect the MCS development during periods when the system continues moving eastward. Compared to some typical MCS that happen in Southern China, which are usually accompanied with upward development of cyclonic vorticity, the development and evolution of the investigated MCS shows distinguishing features. In this article, the physical mechanisms responsible for the intensification of mid-level disturbance are discussed, and a viewpoint to interpret the effects of mid-level disturbance on the MCS organizational development is proposed.

A unified convergence theory of a numerical method, and applications to the replenishment policies

In determining the replenishment policy for an inventory system, some researchers advocated that the iterative method of Newton could be applied to the derivative of the total cost function in order to get the optimal solution. But this approach requires calculation of the second derivative of the function. Avoiding this complex computation we use another iterative method presented by the second author. One of the goals of this paper is to present a unified convergence theory of this method. Then we give a numerical example to show the application of our theory.

On some difference sequence spaces defined by a sequence of Orlicz functions

The idea of difference sequence spaces was introduced in （Klzmaz, 1981） and this concept was generalized in （Et and Colak, 1995）. In this paper we define some difference sequence spaces by a sequence of Orlicz functions and establish some inclusion relations.

Adaptive terminal sliding mode control for high-order nonlinear dynamic systems

An adaptive terminal sliding mode control (SMC) technique is proposed to deal with the tracking problem for a class of high-order nonlinear dynamic systems. It is shown that a function augmented sliding hyperplane can be used to develop a new terminal sliding mode for high-order nonlinear systems. A terminal SMC controller based on Lyapunov theory is designed to force the state variables of the closed-loop system to reach and remain on the terminal sliding mode, so that the output tracking error then converges to zero in finite time which can be set arbitrarily. An adaptive mechanism is introduced to estimate the unknown parameters of the upper bounds of system uncertainties. The estimates are then used as controller parameters so that the effects of uncertain dynamics can be eliminated. It is also shown that the stability of the closed-loop system can be guaranteed with the proposed control strategy. The simulation of a numerical example is provided to show the effectiveness of the new method.

A new cable truss support system for coal roadways affected by dynamic pressure

The support of coal roadways is seriously affected by intense dynamic pressures.This can lead to problems with large deformation of the roof and the two side walls of coal roadways.Rapid convergence of the walls and roof,a high damage rate to the bolts and cables,or even abrupt roof collapse or rib spalling can occur during the service period of these coal roadways.Analyzing the main support measures used in China leads to a proposed new cable truss supporting system.Thorough study of the entire structure shows the superiority of this design for roadways suffering under dynamic pressure.A corresponding mechanical model of the rock surrounding the cable truss system is described in this paper and formulas for calculating pre-tightening forces of the truss cable,and the minimum anchoring forces,were deduced.The new support system was applied to a typical roadway affected by intensive dynamic pressure that is located in the Xinyuan Coal Mine.The results show that the largest subsidence of the roof was 97 mm,the convergence of the two sides was less than 248 mm,and the average depth of the loose,fractured layer was only 6.12 mm.This proves that the new support system is feasible and effective.

A General Projection Method for a System of Relaxed Coercive Variational Inequalities in Hilbert Spaces

In this paper,we consider a new algorithm for a generalized system for relaxed coercive nonlinear inequalities involving three different operators in Hilbert spaces by the convergence of projection methods.Our results include the previous results as special cases extend and improve the main results obtained by many others.

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.

Convergent mechanism of roadway driven along with strong roof of special thick stratum and its controlled measures

The trapezoidal cross-section roadway, driven along with its medium and fine grain sandstone roof in special thick stratum, was situated in shale strata. Rock-lining wall was employed in roadway, which its roof is in the free situation. Under the action of virgin stress, the surrounding rock of roadway was in stability. While under the action of fixed abutment pressure arisen from protection pillar of roadway, which its two sides?seams were extracted, free strong roof of roadway was in the stability. But its two sides?rock-lining walls was fractured, partially broken into pieces, and its floor heave was ob-vious. The velocity of floor heave is 0.4～0.8 mm/d. The size of broken zone of sur-rounding rock of roadway increases doubly. An effective load coefficient of surrounding rock to was quoted illustrate these phenomena. The main reasons of roadway conver-gence are that, rock property of surrounding rock is inferior, protection pillar affects its stability, and supporting pattern employed is improper. At last, effective measures to control roadway convergence should be bolting and grouting lining, which mainly con-solidates surrounding rock of roadway.

Unscented Particle Filter Algorithm for Ballistic Target Tracking

At present, the ballistic Target tracking has a higher demand in convergence rate and tracking precision of filter algorithm. In the paper, a filter algorithm was improved based on particle filter. The algorithm was carried out from the aspects such as particle degradation and particle diversity lack. A novel ballistic coefficient parameter model was built, and was expanded to the state vector for filtering. Finally, the improved algorithm was simulated by MATLAB software. The simulation results show that the algorithm can obtain better convergence speed and tracking precision.

Global optimization by small-world optimization algorithm based on social relationship network

A fast global convergence algorithm, small-world optimization (SWO), was designed to solve the global optimization problems, which was inspired from small-world theory and six degrees of separation principle in sociology. Firstly, the solution space was organized into a small-world network model based on social relationship network. Secondly, a simple search strategy was adopted to navigate into this network in order to realize the optimization. In SWO, the two operators for searching the short-range contacts and long-range contacts in small-world network were corresponding to the exploitation and exploration, which have been revealed as the common features in many intelligent algorithms. The proposed algorithm was validated via popular benchmark functions and engineering problems. And also the impacts of parameters were studied. The simulation results indicate that because of the small-world theory, it is suitable for heuristic methods to search targets efficiently in this constructed small-world network model. It is not easy for each test mail to fall into a local trap by shifting into two mapping spaces in order to accelerate the convergence speed. Compared with some classical algorithms, SWO is inherited with optimal features and outstanding in convergence speed. Thus, the algorithm can be considered as a good alternative to solve global optimization problems.

The Convergence of 1-Periodic Branched Continued Fraction of the Special Form in Parabolic Regions

Branched continued fractions are one of the multidimensional generalization of the continued fractions. Branched continued fractions with not equivalent variables are an analog of the regular C-fractions for multiple power series. We consider 1-periodic branched continued fraction of the special form which is an analog fraction with not equivalent variables if the values of that variables are fixed. We establish an analog of the parabola theorem for that fraction and estimate truncation error bounds for that fractions at some restrictions. We also propose to use weight coefficients for obtaining different parabolic regions for the same fraction without any additional restriction for first element.

A Graph-based Ant Colony Optimization Approach for Integrated Process Planning and Scheduling

This paper considers an ant colony optimization algorithm based on AND/OR graph for integrated process planning and scheduling(IPPS). Generally, the process planning and scheduling are studied separately. Due to the complexity of manufacturing system, IPPS combining both process planning and scheduling can depict the real situation of a manufacturing system. The IPPS is represented on AND/OR graph consisting of nodes, and undirected and directed arcs. The nodes denote operations of jobs, and undirected/directed arcs denote possible visiting path among the nodes. Ant colony goes through the necessary nodes on the graph from the starting node to the end node to obtain the optimal solution with the objective of minimizing makespan. In order to avoid local convergence and low convergence, some improved strategy is incorporated in the standard ant colony optimization algorithm. Extensive computational experiments are carried out to study the influence of various parameters on the system performance.

Improved Consensus Speed for Discrete-Time Multi-agent Systems

The consensus problem of a linear discrete-time multi- agent system with directed communication topologies was investigated. A protocol was designed to solve consensus with an improved convergence speed achieved by designing protocol gains. The clo6ed-loop multi.agent system converged to an expected type of consensus function, which was divided into four types： zero, non- zero constant vector, bounded trajectories, and ramp trajectories. An algorithm was further provided to construct the protocol gains, which were determined in terms of a classical pole placement algorithm and a modified algebraic Riccati equation. Finally, an example to illustrate the effectiveness of theoretical results was presented.

On convergence of the inexact Rayleigh quotient iteration with the Lanczos method used for solving linear systems

For the Hermitian inexact Rayleigh quotient iteration （RQI）, we consider the local convergence of the inexact RQI with the Lanczos method for the linear systems involved. Some attractive properties are derived for the residual, whose norm is ξk, of the linear system obtained by the Lanczos method at outer iteration k ＋ 1. Based on them, we make a refined analysis and establish new local convergence results. It is proved that （i） the inexact RQI with Lanezos converges quadratically provided that ξk ≤ξ with a constant ξ≥） 1 and （ii） the method converges linearly provided that ξk is bounded by some multiple of 1/‖τk‖ with ‖τk‖ the residual norm of the approximate eigenpair at outer iteration k. The results are fundamentally different from the existing ones that always require ξk 〈 1, and they have implications on effective implementations of the method. Based on the new theory, we can design practical criteria to control ξk to achieve quadratic convergence and implement the method more effectively than ever before. Numerical experiments confirm our theory and demonstrate that the inexact RQI with Lanczos is competitive to the inexact RQI with MINRES.

Sieve M-estimator for a semi-functional linear model

We propose sieve M-estimator for a semi-functional linear model in which the scalar response is explained by a linear operator of functional predictor and smooth functions of some real-valued random variables.Spline estimators of the functional coefficient and the smooth functions are considered,and by selecting appropriate knot numbers the optimal convergence rate and the asymptotic normality can be obtained under some mild conditions.Some simulation results and a real data example are presented to illustrate the performance of our estimation method.

CONVERGENCE OF THE LAX-FRIEDRICHS SCHEME AND STABILITY FOR CONSERVATION LAWS WITH A DISCONTINUOUS SPACE-TIME DEPENDENT FLUX

The authors give the first convergence proof for the Lax-Friedrichs finite differencescheme for non-convex genuinely nonlinear scalar conservation laws of the formu_t + f(k(x, t), u)_x = 0,where the coefficient k(x, t) is allowed to be discontinuous along curves in the (x, t)plane. In contrast to most of the existing literature on problems with discontinuouscoefficients, here the convergence proof is not based on the singular mapping approach,but rather on the div-curl lemma (but not the Young measure) and a Lax type en-tropy estimate that is robust with respect to the regularity of k(x, t). Following [14],the authors propose a definition of entropy solution that extends the classical Kruzkovdefinition to the situation where k(x, t) is piecewise Lipschitz continuous in the (x, t)plane, and prove the stability (uniqueness) of such entropy solutions, provided that theflux function satisfies a so-called crossng condition, and that strong traces of the solu-tion exist along the curves where k(x, t) is discontinuous. It is shown that a convergentsubsequence of approximations produced by the Lax-Friedrichs scheme converges tosuch an entropy solution, implying that the entire computed sequence converges.

Convergence of global attractors of a 2D non-Newtonian system to the global attractor of the 2D Navier-Stokes system

This paper discusses the relation between the long-time dynamics of solutions of the two-dimensional （2D） incompressible non-Newtonian fluid system and the 2D Navier-Stokes system. We first show that the solutions of the non-Newtonian fluid system converge to the solutions of the Navier-Stokes system in the energy norm. Then we establish that the global attractors {.Aε^H}0〈≤1 of the non-Newtonian fluid system converge to the global attractor .A0H of the Navier-Stokes system as ε → 0. We also construct the minimal limit A^H min of the H global attractors {Aε^H}0〈ε≤ as ≤→ 0 and prove that A^Hmin iS a strictly invariant and connected set.