复杂串联系统的状态空间生成的形式化分析

大规模系统的模型状态空间生成过程由于状态空间的规模没有预先估计而不可控,形式化分析有利于解决这一问题。本文针对复杂串联系统的特殊结构,采用形式化方法分析研究了它的状态空间生成规律,从而达到快速预估模型状态空间规模的目的。     

基于积分时滞系统史密斯预估器的研究

在积分时滞系统(IPDT)中,传统的史密斯预估器不能很好的消除稳态误差,而且在模型失配时易产生欠补偿问题.为此,文中提出了改进型的史密斯预估器,首先利用反馈控制器,将实际过程与模型过程的误差反馈到控制信号端.其次,在控制对象端加上串联控制器和反馈补偿控制器,分别采用不同的方法进行设计,以消除扰动对系统的影响. MATLAB仿真结果显示,系统具有较好的输出响应,能够有效消除扰动误差.     

基于TSK模糊系统的生化变量预估模型

提出了一种利用TSK(Takagi-Sugeno-Kang)模糊系统建立生化变量预估模型的方法,用于生化过程的工艺参数预测。利用TSK模糊系统的非线性逼近能力,以谷氨酸发酵过程为研究对象,建立了基于TSK模糊逻辑系统的生化变量预估器。以工厂现场采集的发酵过程参数大量数据为样本,训练TSK模糊系统生化变量预估器,并对模型的预估精度进行检验。仿真结果显示了预估模型的有效性,可以有效地预测谷氨酸发酵过程中生化变量的估计值。TSK模糊系统生化变量预估模型能预估生化过程中工业发酵罐的放罐时间,预估模型的状态预报对正常罐批具有足够高的预报精度,预报误差如果偏大亦可作为异常罐批的早期警示信息。有鉴于此,TSK模糊逻辑系统可望开辟生化过程参数预估的新途径。     

基于模糊自适应控制的温度控制系统研究

针对一些系统大延时滞后的特点,本文以温度为对象,结合模糊控制技术和自适应Smith预估器,组成模糊自适应Smith预估控制系统。运用Simulink建立温度控制系统的仿真模型,并分别用常规模糊控制技术和模糊自适应Smith预估控制技术对温度加温进行仿真试验。仿真结果表明在温度加温的模糊控制系统中增加自适应Smith预估器后,系统具有更强的适应能力,系统的动态特性都有了较大的改善。     

多变量时滞过程二自由度Smith预估控制方法

针对工业系统中普遍存在的多变量时滞过程,提出了一种二自由度Smith预估控制的方法。通过在被控过程前串联反向解耦矩阵,实现标称系统的完全解耦。在此基础上,运用Dahlin控制算法和内模控制方法,对解耦后的过程分别设计了设定值跟随控制器和干扰抑制控制器,并基于最大灵敏度实现了干扰抑制控制器参数的鲁棒整定。仿真结果表明:该方法设计简单、整定方便,而且具有良好的跟踪特性、抗干扰特性和鲁棒性。     

自适应修正Smith算法在时滞系统中的应用

传统的Smith预估补偿控制要求较高的对象模型精度，为了提高系统的鲁棒性，提出了一种改进的Smith预估器。该算法根据历史预估结果动态地对预估输出进行修正，从而提高预估精度。将其应用于大时滞温控系统，取得了准确的预估输出和良好的控制品质。算法实现简单、应用灵活、适应性强，可以应用于其他有滞后影响的场合。     

Smith预估控制的工程实现

Smith预估控制也叫纯滞后补偿控制。本文介绍了Smith预估控制的应用领域和应用对象,叙述了Smith预估控制在工程上如何实现及其基本原理,以及北京和利时集团的DCS系统关于Smith预估控制的工程实现方法和各种扰动试验的结果。     

基于改进Smith预估器的二阶时滞系统

在关于工业过程控制的研究中,针对常规Smith预估器是基于时滞对象精确数学模型,而在实际应用中,当被控系统的参数不稳定或受到扰动时,就会造成Smith预估模型的失控,使得控制效果变差甚至振荡.尽管模糊 Smith预估控制对系统参数的变化不敏感,但并没有从本质上克服预估模型失控给系统带来的不稳定性影响.为解决时滞引起失控的问题,提出了一种改进的模糊Smith预估控制方法,并对方法进行了仿真.仿真结果表明,能够增强系统的稳定性、鲁棒性,并且具有较好的控制精度,为实际工程设计提供了参考.     

模糊自适应Smith预估器在温室控制中的应用研究

该文以蒸汽管道为对象,采用机理分析法对温室加温时的温度对象进行分析,得到室内温度模型和蒸汽管道模型。采用模糊控制技术,组成温室温度的模糊控制系统。针对温室系统大延时滞后的特点,采用自适应Sm ith预估器对温室模糊控制系统进行补偿,组成模糊自适应Sm ith预估控制系统。运用MATLAB软件的S imu link建立温室控制系统的仿真模型,并分别用常规模糊控制技术和模糊自适应Sm ith预估控制技术对温室加温进行仿真试验,仿真结果表明在温室加温的模糊控制系统中增加自适应Sm ith预估器后,系统具有更强的适应能力,系统的动态特性都有了较大的改善。     

基于结构分散化控制的球磨机制粉系统控制与仿真

按照球磨机制粉过程运动特性的基本因果关系,建立一种球磨机制粉过程的结构分散化模型,它由6个单元模型、3条因果链和4支链间关联的模型构成.以该模型为基础,设计球磨机制粉过程的预估系统,它拥有单元预估系统、基本关联模型和依托因果链的预估信息传递模型,保证在子系统设计预估算法,仍然能够获得对整体系统运动特性的满意预估.设计球磨机制粉过程的控制系统,它包含单元控制系统和依托因果链的控制指令传递模型,保证在子系统设计控制算法,仍然能够获得对整体系统的期望控制性能.该新型控制系统应用于球磨机制粉过程控制,具有良好的稳定性、抗干扰和容错能力.     

输入输出双线性系统的递推辨识与实现算法

本文对输入输出双线性系统给出了一套完整的辨识方法。首先给出了输入输出方程的一般形式,并对于一类规范型给出了相应地输入输出差分方程。然后给出了确定系统的结构指标和参数估计的递推算法,它改进了由Katta和Nurges(1984)给出的方法,大大缩短了计量时间。另外,还给出了状态方法的简单实现算法。最后,给出了仿真例子说明算法的有效性。     

Extrapolation of the boundary of uni- and bimodality of a two-component Gaussian mixture

A two-component Gaussian mixture with equal variances and various mathematical expectations has been studied. It has been found that a set of singular critical points of its probability density is a boundary of uni- and bimodality. The approximation equation of this boundary has been obtained on a line segment as a second-degree polynomial. The bifurcation area of the function being investigated is presented in the probabilistic form. The extrapolation algorithm of this boundary has been developed on a small line, and the experimental results have been presented.     

Distributing a Data Base with Logical Associations on a Computer Network for Parallel Searching

The problem of distributing a data base (with logical associations between segment types) on a computer network such that multiple segment types satisfying a query can be retrieved in paralel from different nodes has been introduced. Properties of such distributions without redundancy and with redundancy have been discussed. Lower bounds on the number of nodes needed for such distributions have been given. Algorithms for constructing such distributions have also been given. Distributions of data bases for queries whose target segments form a combinatorial set have been studied in detail. Closed form expressions for redundancy have been obtained for such query sets.     

Unilateral plate contact with the elastic-plastic winkler-type foundation

In this work contact problems of a plate with the elastic-plastic Winkler-type foundation has been solved. An unilateral character of bonds between plate and foundation has been taken into consideration. The effect of friction forces in the contact plane has been neglected and an incremental approach has been applied. An incremental problem has been formulated in a variational manner and solved by use of the finite element method. The results of numerical calculations for rectangular plates subjected to the simple and complex load processes have been presented.     

Generating good pseudo-random numbers

A widely used pseudo-random number generator has been shown to be inadequate by today's standards. In producing a revised generator, extensive use has been made of a test package TestU01 for random number generators. Using this, criteria have been devised for the revised generator—also other high-quality generators have been identified. Facilities have been devised to allow the new generator to be used in a highly parallel environment, which is likely to be a feature of many future applications.     

简体中文垃圾邮件分类的实验设计及对比研究

综合分析了垃圾邮件过滤的技术路线与方法,并在分析基于关键字的方法和统计学的方法的基础上,提出了将两者相结合,运用模式识别中的贝叶斯、最近邻和感知机等分类方法,实现对垃圾邮件的过滤的技术路线。以互信息最大化准则筛选出的特征集为基础,对不同分类技术的对比分析揭示了贝叶斯、最近邻和感知机在垃圾邮件过滤应用上的优劣。同时,文中对基于互信息最大化准则的垃圾邮件过滤应用提出了有益的思路。     

Substrate integrated non-radiative dielectric waveguide and its applications

In this article a Substrate Integrated Non Radiative Dielectric Guide (SINRD) has been realized with the concept of substrate integration circuits. In SINRD, a specific pattern of air holes have been used grooved in a dielectric substrate to reduce the effective dielectric constant of a particular region. Accordingly, design and implementation of SINRD guides and its applications in millimeter wave subsystems have been investigated by using published literatures. Thereby the concept has been utilized to develop an optimized design flow of SINRD transmission line. Design has been carried out at W band (85–110 GHz) on a high dielectric constant substrate and subsequently dispersion characteristics has been studied subject to transmitted and radiated field configuration.

     

A single period inventory model with a truncated normally distributed fuzzy random variable demand

In this article, a single period inventory model has been considered in the mixed fuzzy random environment by assuming the annual customer demand to be a fuzzy random variable. Since assuming demand to be normally distributed implies that some amount of demand information is being automatically taken to be negative, the model has been developed for two cases, using the non-truncated and the truncated normal distributions. The problem has been developed to represent scenarios where the aim of the decision-maker is to determine the optimal order quantity such that the expected profit is greater than or equal to a predetermined target. This ‘greater than or equal to’ inequality has been modelled as a fuzzy inequality and a methodology has been developed to this effect. This methodology has been illustrated through a numerical example.     

Simulations of adiabatic chemical reactions in condensed media

Algorithms of the simulation of adiabatic chemical reactions in condensed media have been developed. The time behavior of a newly introduced collective coordinate of the media has been studied for model reaction of electron excitation of a single active particle. Theoretical justification of the algorithms has been carried out. The dependence of correlation functions of the collective coordinate of media on temperature has been studied numerically. The dependency of the reaction rate on temperature has been numerically calculated based on the algorithms developed. The correspondence between the calculated rate-temperature curve and simple formulas of chemical kinetics has been shown.