Design of noise and period-time robust high-order repetitive control, with application to optical storage

Repetitive control is useful if periodic disturbances or setpoints act on a control system. Perfect (asymptotic) disturbance rejection is achieved if the period time is exactly known. The improved disturbance rejection at the periodic frequency and its harmonics is achieved at the expense of a degraded system sensitivity at intermediate frequencies. A convex optimization problem is defined for the design of high-order repetitive controllers, where a trade-off can be made between robustness for changes in the period time and for reduction of the error spectrum in-between the harmonic frequencies. The high-order repetitive control algorithms are successfully applied in experiments with the tracking control of a CD-player system.     

电梯交通系统(Ⅰ)──电梯交通配置现状及发展

本文对国内外电梯交通配置设计现状及发展趋势作了论述。指出了由统计特性描述进入到采用专家系统和模糊规则的动态特性描述这一总的发展趋势。     

Simulating the Child's Acquisition of the Lexicon and Syntax—Experiences With Babel

This paper describes the theory and implementation ofBabel, a system which explores the hypothesis that much of the differences in the world's languages may be characterized by the inventory and properties of the lexical items and functional categories of those languages. The structure ofBabel assumes that functional categories are originally lacking in a child's syntax, and are acquired through a statistical induction process of lexical acquisition.Babel then uses information induced from the structure of the lexicon to create a model of syntax via a deductive, rule-based process. This model makes a number of predictions about the time course of language acquisition. These predictions are tested by runningBabel as a simulation of child language acquisition, using large samples of adult speech to children as input. The simulation results are shown to highly correlate to longitudinal studies of child language acquisition in English and Polish. Finally, the approach to handling noisy data withBabel is detailed.     

差齿原理在推床同步调整技术中的应用

文章应用差齿原理在冶金设备初轧机推拉床实施转角性微调技术，以达到初轧机机前与机后推拉床同步调整效果．实践证明，效果显著，适用面广，且操作简单、方便经济．     

SVPWM三相电压型逆变器的仿真研究

以三相电压型逆变器为基础,根据空间矢量脉宽调制（SVPWM）基本原理详细分析研究了电压矢量作用时间和扇区分配问题,以α-β坐标为基础,建立了互差π/3的x-y-z时间坐标系,提出了不同扇区矢量作用时间长短根据期望极值判断的原则。介绍了MATLAB中M文件编程的仿真方法,建立了MATLAB程序嵌入式主要功能模块,逆变器采用数字PID控制,利用Simulink对系统进行了综合仿真分析及试验,给出了仿真及实验波形,为实现SVPWM逆变器的数字控制提供参考。     

Thermodynamics-inspired inverse halftoning viamultiple halftone images

Based on an analogy between thermodynamics and Bayesian inference,inverse halftoning was formulated using multiple halftone images based on Bayesian inference using the maximizer of the posterior marginal(MPM) estimate.Applying Monte Carlo simulation to a set of snapshots of the Q-Ising model,it was demonstrated that optimal performance is achieved around the Bayes-optimal condition within statistical uncertainty and that the performance of the Bayes-optimal solution is superior to that of the maximum-a-posteriori(MAP) estimation which is a deterministic limit of the MPM estimate.These properties were qualitatively confirmed by the mean-field theory using an infinite-range model established in statistical mechanics.Additionally,a practical and useful method was constructed using the statistical mechanical iterative method via the Bethe approximation.Numerical simulations for a 256-grayscale standard image show that Bethe approximation works as good as the MPM estimation if the parameters are set appropriately.     

抗几何失真的视频Hashing算法研究

文中提出了一种基于视频灰度直方图形状的Hashing算法,能有效抵抗各种常见的几何失真和视频处理操作.算法的鲁棒性原理如下:1)由于直方图的形状与像素位置无关,故基于直方图的视频Hashing算法能有效抵抗各种常见的几何攻击;2)由于在计算Hashing前对视频帧进行了平滑预处理,故算法对加噪攻击、模糊滤波、有损压缩等处理操作有很好的鲁棒性;3)由于计算Hashing前在时间轴上进行了低通滤波预处理,故算法能抵抗帧率变化、帧丢失等时域同步攻击.实验结果表明,所提出的Hashing算法有良好的唯一性和鲁棒性能.     

行为优化提升软件配置管理

软件配置管理包括对代码、文档、数据等的管理,其优劣受限于项目成员的实际操作。开发人员对于工作区如何使用;成员之间的代码是不是可以及时更新与同步;怎样使用分支,如何进行变更合并,才能减少物理空间浪费和事件延迟。这些问题在实际的项目开发中往往被忽视,亦或团队并没有对成员行为作细节的规范,因而许多软件项目出现了工期推迟或代码质量不高等问题。为此提出了一系列管理措施,通过优化软件配置管理规范项目各成员的行为,以保证高效的软件配置管理的实施。     

Consistency retention method for CNC machine tool digital twin model

Computer Numerical Control Machine Tool (CNCMT) Digital Twin (DT) model is a carrier for complex, time-varying, coupled data of CNCMT, which can theoretically provide a time-varying high-fidelity model. However, there are still many difficulties in its implementation process. And the key issue is how to realize the updated DT model with performance attenuation and validate it. In order to solve this problem, a model consistency retention method for CNCMT DT model is studied and proposed in this paper. Firstly, the framework of consistency retention method for DT model is designed including both digital space and physical space. The principles of data management and performance attenuation update in digital space are elaborated. Then, the implementation method for consistency retention of CNCMT DT model is studied in terms of performance attenuation update workflow for wear and other damage separately. Finally, a case study for the establishment and application of high-fidelity test bench DT model that focusing on rolling guide-rail is carried out to show the implementation flow of the proposed method and verify its operability and effectiveness.