小型绝对式光电编码器误码自动检测系统

在批量生产光电编码器时,对光电编码器是否存在误码进行检测是一个重要的环节。现有的检测方法采用二进制灯排手动转动编码器用肉眼进行观测,存在手动检测慢、肉眼观测误差较大、检测结果受转动速度影响等缺点。在大批量生产的光电编码器,采用传统方法进行误码检测费时费力。为解决编码器生产及使用过程中对光电编码器的自动误差检测,本文设计了小型光电编码器误码自动检测系统。首先,在参照大量光电编码器生产经验的基础上,分析了编码器误码产生的主要原因;然后,提出了基于微分算法实现对光电编码器是否存在误码进行判断的误码自动检测方法;最后,以FPGA为主控芯片,设计了小型光电编码器自动误码检测系统。该系统能够实现对光电编码器的高速数据采集、数据处理与误码判断,并将误码判断结果通过LCD液晶显示。同时,可以根据需要将数据传输到计算机中作进一步分析。检测实验表明:本文所设计的误码检测系统成功实现了对15位串/并口光电编码器在高速和低速下进行数据采集及误码判断。系统可用于批量生产下光电编码器的误码自动检测,减少了人工操作,提高了自动化程度。系统具有智能便捷,移动性强,适用于实验室及各种工作场合下的误码检测等优点,检测速度较以往检测方法提高了3~5倍。     

双线性Fourier乘子交换子的有界性与紧性

假定T_σ是关于乘子σ的双线性Fourier乘子算子,其中σ满足如下Sobolev正则条件:对某个s∈(n,2n],有sup_(κ∈Z)‖σ_k‖W~s(R~(2m))∞.对于p_1,p_2,p∈(1,∞)且满足1/p=1/p_1+1/p_2和ω=(ω_1,ω_2)∈A_(p/t)(R~(2n)),建立了T_σ及其与函数b=(b_1,b_2)∈(BMO(R~n))~2生成的交换子T_(σ,b)由L~(p_1,λ)(ω_1)×L~(p_2,λ)(ω_2)到L~(p,λ)(v_w)的有界性;同时,在b_1,b_2∈CMO(R~n)(C_c~∞(R~n)在BMO拓扑下的闭包)的条件下,证明交换子T_(σ,b)是L~(p_1,λ)(ω_1)×L~(p_2,λ)(ω_2)到L~(p,λ)(v_w)的紧算子.为了得到主要结果,我们先后建立了几个双(次)线性极大函数在加多权Morrey空间上的有界性以及该空间中准紧集的判定.     

沿复合子簇的粗糙核极大算子

给出了两类相关于沿复合子簇的粗糙核奇异积分的极大算子的L~p有界性,本质上极大地改进和一般化了已有的结果.作为应用,相关的奇异积分,Marcinkiewicz积分和相应的极大算子的L~p有界性也被建立.     

On convergence of iterative methods for maximal correlation problems

Several iterative methods for maximal correlation problems (MCPs) have been proposed in the literature. This paper deals with the convergence of these iterations and contains three contributions. Firstly, a unified and concise proof of the monotone convergence of these iterative methods is presented. Secondly, a starting point strategy is analysed. Thirdly, some error estimates are presented to test the quality of a computed solution. Both theoretical results and numerical tests suggest that combining with this starting point strategy these methods converge rapidly and are more likely converging to a global maximizer of MCP. Copyright © 2016 John Wiley & Sons, Ltd.     

A splitting algorithm for a class of bilevel equilibrium problems involving nonexpansive mappings

We propose splitting, parallel algorithms for solving strongly equilibrium problems over the intersection of a finite number of closed convex sets given as the fixed-point sets of nonexpansive mappings in real Hilbert spaces. The algorithm is a combination between the gradient method and the Mann-Krasnosel’skii iterative scheme, where the projection can be computed onto each set separately rather than onto their intersection. Strong convergence is proved. Some special cases involving bilevel equilibrium problems with inverse strongly monotone variational inequality, monotone equilibrium constraints and maximal monotone inclusions are discussed. An illustrative example involving a system of integral equations is presented.     

A stronger version of the Kleiman‐Chevalley projectivity criterion

We strengthen the classical Kleiman‐Chevalley projectivity criterion by showing that it is enough to assume that instead of .     

Degenerate asymmetric quantum concatenated codes for correcting biased quantum errors

In most practical quantum mechanical systems, quantum noise due to decoherence is highly biased towards dephasing. The quantum state suffers from phase flip noise much more seriously than from the bit flip noise. In this work, we construct new families of asymmetric quantum concatenated codes (AQCCs) to deal with such biased quantum noise. Our construction is based on a novel concatenation scheme for constructing AQCCs with large asymmetries, in which classical tensor product codes and concatenated codes are utilized to correct phase flip noise and bit flip noise, respectively. We generalize the original concatenation scheme to a more general case for better correcting degenerate errors. Moreover, we focus on constructing nonbinary AQCCs that are highly degenerate. Compared to previous literatures, AQCCs constructed in this paper show much better parameter performance than existed ones. Furthermore, we design the specific encoding circuit of the AQCCs. It is shown that our codes can be encoded more efficiently than standard quantum codes.