注塑机注射速度的模型预测迭代学习控制

针对注射过程具有重复运行和非线性的特性,在对预测控制与迭代学习控制进行综合应用并加以改进的基础上,给出一种模型预测迭代学习复合控制新算法,研究了控制器的设计方案.同时,将迭代学习思想引入到预测步长的在线调整,提出了预测步长的迭代学习方法.仿真结果表明,该方法是有效的,其控制性能优于PID迭代学习控制系统.     

On guiding the augmentation of an automated test suite via mutation analysis

Mutation testing has traditionally been used as a defect injection technique to assess the effectiveness of a test suite as represented by a “mutation score.” Recently, mutation testing tools have become more efficient, and industrial usage of mutation analysis is experiencing growth. Mutation analysis entails adding or modifying test cases until the test suite is sufficient to detect as many mutants as possible and the mutation score is satisfactory. The augmented test suite resulting from mutation analysis may reveal latent faults and provides a stronger test suite to detect future errors which might be injected. Software engineers often look for guidance on how to augment their test suite using information provided by line and/or branch coverage tools. As the use of mutation analysis grows, software engineers will want to know how the emerging technique compares with and/or complements coverage analysis for guiding the augmentation of an automated test suite. Additionally, software engineers can benefit from an enhanced understanding of efficient mutation analysis techniques. To address these needs for additional information about mutation analysis, we conducted an empirical study of the use of mutation analysis on two open source projects. Our results indicate that a focused effort on increasing mutation score leads to a corresponding increase in line and branch coverage to the point that line coverage, branch coverage and mutation score reach a maximum but leave some types of code structures uncovered. Mutation analysis guides the creation of additional “common programmer error” tests beyond those written to increase line and branch coverage. We also found that 74% of our chosen set of mutation operators is useful, on average, for producing new tests. The remaining 26% of mutation operators did not produce new test cases because their mutants were immediately detected by the initial test suite, indirectly detected by test suites we added to detect other mutants, or were not able to be detected by any test.

基于DCS的循环流化床锅炉床温模糊控制技术

循环流化床锅炉是一个具有分布参数、非线性、时变、大滞后、多变量紧密耦合的多输入多输出的变参数系统,常规控制方法难以取得理想的控制效果。该文根据循环流化床锅炉运行特性,提出基于DCS实现的循环流化床锅炉床温模糊控制技术,实践表明控制效果理想,具有良好的应用前景。     

Reliable control strategy based on sliding mode observer against FDI attacks in smart grid

This paper is concerned with the reliable operation of cyber-physical systems under false data injection attacks. First of all, a robust adaptive sliding mode observer is designed to estimate the state of the power system; different from the traditional sliding mode observer, the observer we designed is not only robust to state errors but also can automatically adjust the parameter of attack identification. Secondly, a method of attack reconstruction has been given to estimate the actual attack signal. Finally, a reliable sliding mode control strategy is proposed to eliminate the impact of false data injection attacks; compared with the existing results, the designed defense strategy utilizes the reconstructed attack signal in the attack identification scheme and state error signal at the same time. Moreover, a power system with 3 generator buses and 6 load buses is taken as an simulation example to verify the availability of the proposed control strategy.     

电镀塑料制品对结构设计及成形工艺的要求

为保证电镀塑料制品的质量,提出了符合电镀要求的塑料制品设计原则,并且指出在注塑成形时,对塑料经过充分干燥,采用较高的注塑温度,较低的注射压力和较慢的注射速度,是使镀层获得良好结合强度的先决条件。     

变频技术在锅炉风机中的应用

针对袁店二矿锅炉鼓风机、引风机采用工频运行方式存在电网冲击大、电能浪费严重的问题,提出采用变频技术改造的方法;分析了变频节能原理、变频控制原理及节能效果。在风机设备上使用变频技术调节电动机转速和风量,可精确地调节锅炉送风量及引风量,不仅提高了锅炉热效率及燃烧效率,而且节能降耗效果显著,平均节能在30%~40%左右。     

基于DSP和电流环的锅炉温度控制系统设计

提出了基于DSP和电流环的锅炉温度控制系统设计方案,详细介绍了电流环发生器和接收器、DSP处理模块及其控制算法的设计。该系统采用TMS320F2812 DSP作为控制器,以4～20 mA电流环为传输方式,利用PID算法实现了对锅炉的温度控制,具有较高的灵活性和可靠性。     

An MRAS method for sensorless control of induction motor over a wide speed range

This paper addresses the problem of wide speed range sensorless control of induction motor.The proposed method is based on model reference adaptive system (MRAS),in which the current model serves as the adjustable model,and a novel hybrid model integrating the modified voltage model (MVM) and high-frequency signal injection method (HFSIM) are established to serve as the reference model.The HFSIM works together with MVM to improve the performance of the rotor speed and rotor flux position estimation at low speed,whereas at high speed,the MVM acts alone.In addition,a rotor resistance online estimation scheme is proposed to update the rotor resistance contained in the adjustable model and to ensure the estimation accuracy further.Experimental results show that the proposed MRAS method is very effective from low to high speed range,including zero speed.     

舰用主汽轮机组在海水温度变化情况下最大工作能力分析

针对舰用主汽轮机组的工作环境特性,基于热力学和流体力学基本理论,建立冷凝器工作特性模型,并运用Matlab/Simulink进行求解,定量分析了海水温度变化对舰用冷凝器压力、主汽轮机组功率和舰船航速的影响。研究成果对如何充分发挥装备的最大使用效能,具有重要的指导意义。     

政府网站运行的安全性问题研究

本文以政府部门计算机网络和网站在运行中碰到的安全问题,阐述了如何建设相对安全的网控中心,并对因特网上发布信息的网站所受到的各种攻击作出了说明,以及如何采用各种技术方法和措施填补漏洞、防范攻击,保障网站安全。