Absolutely Stable of Takagi-Sugeno Fuzzy Control System by Using Popov’s Criterion

In this paper, we presented a sufficient condition on the frequency domain for the absolutely stable analysis of the Takagi-Sugeno (T-S)fuzzy control system, based on the Popov’s criterion. we use some numerical examples to illustrate the efficiency of frequency domain-based condition.

A novel extended Tsypkin criterion for discrete-time descriptor systems with ferromagnetic hysteresis nonlinear physical phenomenon

This paper concerns the absolute stability problem of discrete-time descriptor systems with feedback connected ferromagnetic hysteresis nonlinearities. The ferromagnetic hysteresis model satisfies the passivity conditions of hysteresis operator, that is the input-output relation of the transformed operator is passive. The bound condition of the solution of the ferromagnetic hysteresis model is given. Through the framework of loop transformation, an augmented discrete-time descriptor system model is established for the stability analysis. A new extended Tsypkin criterion for the absolute stability of discrete-time descriptor systems with hysteresis is presented based on the linear matrix inequalities technique. A numerical example is given to illustrate the effectiveness of the extended criterion.

New criterion in predicting glass forming ability of various glass-forming systems

It has been confirmed that glass-forming ability （GFA） of supercooled liquids is related to not only liquid phase stability but also the crystallization resistance. In this paper, it is found that the liquid region interval （T1 - Tg） characterized by the normalized parameter of Tg/T1 could reflect the stability of glass-forming liquids at the equilibrium state, whilst the normalization of supercooled liquid region △Tx=（Tx - Tg）, i.e. △Tx/Tx （wherein T1 is the liquidus temperature, Tg the glass transition temperature, and Tx the onset crystallization temperature） could indicate the crystallization resistance during glass formation. Thus, a new parameter, defined as ζ = Tg/T1＋△Tx/Tx is established to predict the GFA of supercooled liquids. In comparison with other commonly used criteria, this parameter demonstrates a better statistical correlation with the GFA for various glass-forming systems including metallic glasses, oxide glasses and cryoprotectants.

Viability decision of linear discrete-time stochastic systems with probability criterion

In this paper, the optimal viability decision problem of linear discrete-time stochastic systems with probability criterion is investigated. Under the condition of sequence-reachable discrete-time dynamic systems, the existence theorem of optimal viability strategy is given and the solving procedure of the optimal strategy is provided based on dynamic programming. A numerical example shows the effectiveness of the proposed methods.

Reliability Optimization of Entropy Based Series-Parallel System Using Global Criterion Method

In this paper, we have considered a series-parallel system to find out optimum system reliability with an additional entropy objective function. Maximum system reliability of series-parallel system is depending on proper allocation of redundancy component in different stage. The goal of entropy based reliability redundancy allocation problem is to find optimal number of redundancy component in each stage such a manner that maximize the system reliability subject to available total system cost. Global criterion method is used to analyze entropy based reliability optimization problem with different weight function of objective functions. Numerical examples have been provided to illustrate the model.

A blowup criterion for the 3D generalized MHD system with zero magnetic diffusivity

This paper proves a new regularity criterion ω: = rotu∈L1(0,T;B·0∞,∞) for the 3D generalized MHD system with fractional diffusion terms(-Δ)αu with α >9/8 and zero magnetic diffusivity. Here u is the fluid velocity,ω is the vorticity and B·0∞,∞is the homogeneous Besov space.

Stability Criterion with Less LMI Variables for Linear Discrete-time Systems with Additive Time-delays

In this correspondence paper, an equivalent stability criterion with minimal number of linear matrix inequality （LMI） variables is presented for a delay-dependent stability criterion reported recently in the International Journal of Automation and Computing for a class of linear discrete-time systems with additive time delays. The reported stability criterion for the additive timedelay systems has more number of matrix variables in the LMI and, hence, demand additional computational burden. The proposed equivalent stability criterion, unlike the reported one, does not involve free-weighing matrices and encompass only the matrix variables that are associated in the Lyapunov-Krasovskii functional, making the criterion mathematically less complex and computationally more effective.

An Entanglement Criterion for States in Infinite Dimensional Bipartite Quantum Systems

In this paper, an entanglement criterion for states in infinite dimensional bipartite quantum systems is presented. We generalize some of separability criterion that was recently introduced by Wu and Anandan in (Phys. Lett. A, 2002, 297, 4-8) to infinite dimensional bipartite quantum systems. In addition, we give an example aimed to illustrate the application of the theorem.

Simplified Method of Stability Analysis of Nonlinear Systems without Using of Lyapunov Concept

In this paper a new simplified method of stability study of dynamical nonlinear systems is proposed as an alternative to using Lyapunov’s method. Like the Lyapunov theorem, the new concept describes a sufficient condition for the systems to be globally stable. The proposed method is based on the assumption that, not only the state matrix contains information on the stability of the systems, but also the eigenvectors. So, first we will write the model of nonlinear systems in the state-space representation, then we use the eigenvectors of the state matrix as system stability indicators.

“双高”电力系统:一种新的稳定判据和稳定性分类探讨

随着能源变革和电力电子技术发展,高比例新能源和高比例电力电子设备(简称“双高”)在电力系统中比例增高,带来新的稳定问题。该文对“双高”电力系统的失稳影响因素和稳定判据进行深入剖析,探索“双高”电力系统的失稳机理,提出系统阻抗角稳定性分析方法。基于所提出的稳定性分析方法,从系统有功功率、无功功率平衡基本运行规则出发,构建“双高”电力系统的阻抗角稳定判据,通过搭建仿真模型验证所提稳定判据的有效性和正确性。同时,对IEEE 提出的稳定性分类进行探讨,在遵循传统稳定性分类原则基础上,基于所构建的稳定判据,尝试提出一种新的稳定性分类方法,希望有助于厘清“双高”电力系统稳定性问题,为后续系统规划、稳定性控制提供指导。

采动力学与岩层控制关键理论及工程应用

研究岩体采动力学响应和岩层控制技术对促进煤炭安全高效开采、保障能源稳定供给具有重要意义,是实现煤炭资源科学开采的理论基础。矿山岩体灾害(围岩变形、冲击地压等)频发,其形成-演化-发生全过程与采动力演化分布、岩层运动、开采扰动和能量演化密切相关。基于实用矿山压力控制理论,提出并阐述了采场岩层控制进展与控制准则,建立了定量分析的力学模型和设计方法,发展了针对性的岩体灾害控制技术,并创新研制了配套试验研究装备。采动力学与岩层控制理论将岩层控制分为采场岩层控制和巷道围岩控制;提出控制或利用采动岩层运动改变致灾条件,给出“给定变形”和“限定变形”准则;调控“3S”因素准则(围岩应力环境、围岩结构属性、围岩支护结构)改变围岩自稳能力。以岩体灾害控制为目标,提出了以“应力主控”为核心的释能主控技术;建立了岩体灾害控制大小原理和弱面判据(安全系数K、冲击危险性系数U);研发了采场矿压机械模拟试验系统、采动力试验系统和蠕变及动力扰动冲击加载试验系统,实现了实验室尺度还原采动力作用下岩体变形-破裂-运动过程,为研究采动力作用下岩体力学响应提供了试验装备;分别从采场岩层控制、地质软岩巷道控制、工程软岩巷道控制及冲击地压控制4个方向进行了工程案例研究,相关研究成果在工程应用中得到了验证。

国内外文化发展评价标准研究的回顾与展望

用什么样的标准来评价文化发展,对文化的发展方向会起到直接的影响。对于文化强国标准的理论构建、指标体系和实现路径选择进行深入的探讨,具有重大理论意义和现实意义。文化强国理论来源、现实依据和核心内涵与文化强国标准之间的逻辑关系怎样?文化强国标准的历史逻辑、学科基础和构建原则是什么?文化强国标准的内部维度和外部维度是一种怎样的关系?标准确立之后怎样保证指标体系的合理性、客观性、普遍性和可操作性?在创新性标准评价体系的指导下,如何实现路径优化?本文对国内外文化发展评价标准的研究进行了回顾,并在此基础上提出了构建中国特色文化发展评价体系的设想。

Fermentation process modeling of exopolysaccharide using neural networks and fuzzy systems with entropy criterion

The prediction accuracy and generalization of fermentation process modeling on exopolysaccharide (EPS) production from Lactobacillus are often deteriorated by noise existing in the corresponding experimental data. In order to circumvent this problem, a novel entropy-based criterion is proposed as the objective function of several commonly used modeling methods, i.e. Multi-Layer Perceptron (MLP) network, Radial Basis Function (RBF) neural network, Takagi-Sugeno-Kang (TSK) fuzzy system, for fermentation process model in this study. Quite different from the traditional Mean Square Error (MSE) based criterion, the novel entropy-based criterion can be used to train the parameters of the adopted modeling methods from the whole distribution structure of the training data set, which results in the fact that the adopted modeling methods can have global approximation capability. Compared with the MSE- criterion, the advantage of this novel criterion exists in that the parameter learning can effectively avoid the over-fitting phenomenon, therefore the proposed criterion based modeling methods have much better generalization ability and robustness. Our experimental results confirm the above virtues of the proposed entropy-criterion based modeling methods.

基于自由矩阵积分不等式方法的电力系统时滞相关稳定性分析

研究了电力系统时滞相关鲁棒稳定性问题。首先,建立了考虑系统时滞的电力系统模型;然后,通过构造时滞乘积增广型Lyapunov-Krasovskii泛函,并应用自由矩阵积分不等式方法,对泛函导数进行界定,得到了低保守性的稳定新判据;最后,通过单机无穷大系统、4机11节点系统和典型二阶系统验证了所提方法的有效性。

基于ARIMA模型的矿井灾害预测方法研究

矿井灾害频发是影响我国煤炭产业发展的重要问题之一,灾前预警技术是目前应对这一问题的主要方法。为进一步提升矿井灾害监测预警能力,提出了基于ARIMA模型的矿井灾害预测方法研究。通过确立灾害风险监测指标构建了安全态势评估指标体系,基于时序预测法建立了灾害预测评估模型,经模型定阶及训练等过程确定最佳ARIMA预测模型参数。通过研究模型残差的正态性分布从而得到预测模型可靠度,将ARIMA(10,0,0)模型与时间序列拟合后进行自相关图和偏自相关图分析,得到了风险灾害未来短期预测结果;提出了“红橙黄蓝绿”5级灾害预警等级和准则,并进行了现场应用试验,结果证明,ARIMA模型对未来值的预测具有较高准确性,系统能及时对灾害进行预测和分级响应,可实现对矿井灾害的风险判别和预测预警。

基于Routh判据+主导极点法在高阶系统中的稳定性研究

构建了全向机器人在斜坡上运动的受力模型,计算出模型系统函数,分析了载重、坡度θ、惯性等干扰对系统的影响,提出采用Routh判据为该高阶系统稳定条件,用根轨迹主导极点法获得相似2阶系统,观测系统性能指标,获得最优解方案。仿真验证说明,载重K=3.25kg时,全向机器人在斜坡运动系统自校正效果较好,表明采用Routh判据+主导极点法研究高阶系统的稳定性可行有效,为后续研究变值θ扰动下更高阶系统校正提供了一定参考。

串补电容对锁相环主导下变流器振荡问题的影响分析

串联电容补偿技术在电网中被广泛应用,然而串补电容的动态特性对锁相环型变流器的稳定性有重要的影响。为分析此影响,在极坐标下建立变流器经串补并网系统的阻抗模型,并导出考虑串补电容的广义阻抗判据。在此基础上,阐明了串补电容与锁相环的动态耦合以及相应的稳定机制。进一步地,分析了电网强度、串补度和锁相环参数变化对系统稳定性的影响,并提出基于广义阻抗判据的锁相环参数设计方法,以提升变流器经串补并网系统的稳定性。研究表明变流器经串补并网后容易恶化弱电网下锁相环主导的次同步振荡问题,且提升锁相环比例增益可显著增强串补并网系统的稳定性。

基于复值稀疏Bayesian的系统稳定性辨识

稀疏Bayesian学习是近年来机器学习研究的热点,基于Szeg?核的复值稀疏Bayesian学习算法能提供稀疏的有理逼近.提出基于Szeg?核的复值稀疏Bayesian学习算法来判定单位圆盘内闭环系统的稳定性,该方法具有可给出逼近的解析表达式和适用范围更广的优点,并且不需要参数控制进行迭代优化,运算速度快.实验结果表明,此方法是有效的.

基于粗糙集-云模型的城市常规公交运力配置水平评价

为优化完善城市常规公交运力配置的多层次综合评估指标体系及其等级标准,以便科学评估常规公交运力配置水平,提出了一种基于粗糙集-云模型的城市常规公交运力配置水平评估模型。首先,利用粗糙集理论对指标体系进行筛选,并匹配了相应的等级标准;然后,采用CRITIC方法对指标进行赋权,进而利用云模型算法生成评价标准云和结果云,通过数字特征和云图直观展现评价结果。最后,以青岛市主城区144条常规公交线路为例,对模型进行了验证。结果显示:青岛市主城区144条常规公交运力配置水平目标层综合评价等级为“中等”,在子目标层(公交客流水平、公交线路水平、公交线路发车水平、公交车辆运营水平、公交车辆技术水平)中,评价等级为“中等”及以上的占60%,总体上与目前青岛市主城区常规公交运力配置水平特点相符。研究表明,该模型能实现对城市常规公交运力配置的综合评价,可为城市常规公交运力配置评价体系和评价模型构建提供参考。

有偏量测下基于最大相关熵卡尔曼滤波的目标跟踪方法

针对传感器存在系统偏差且噪声非高斯条件下目标状态估计精度较差的问题,提出一种有偏量测下基于最大相关熵卡尔曼滤波(Maximum Correntropy Kalman Filter,MCKF)的目标跟踪方法。该方法通过引入差分机制,利用目标相邻时刻的有偏量测之差构建差分量测方程,有效克服了系统偏差的影响。随后基于最大相关熵准则(Maximum Correntropy Criterion,MCC)量化估计误差的高阶矩信息,并以差分量测为先验条件推导出有偏量测下算法的滤波迭代方程。仿真结果表明,当系统观测值受传感器系统偏差和非高斯噪声干扰时,与现有方法相比,所提方法具有更好的跟踪性能。