Reachable set estimation for discrete-time Markovian jump neural networks with unified uncertain transition probability

This paper focuses on the reachable set estimation for Markovian jump neural networks with time delay.By allowing uncertainty in the transition probabilities,a framework unifies and enhances the generality and realism of these systems.To fully exploit the unified uncertain transition probabilities,an equivalent transformation technique is introduced as an alternative to traditional estimation methods,effectively utilizing the information of transition probabilities.Furthermore,a vector Wirtinger-based summation inequality is proposed,which captures more system information compared to existing ones.Building upon these components,a novel condition that guarantees a reachable set estimation is presented for Markovian jump neural networks with unified uncertain transition probabilities.A numerical example is illustrated to demonstrate the superiority of the approaches.

W ideband interference suppression based on space-time filter

Based upon the diagonal loading technique and the structure of the space-time adaptive processors, a novel anti-jamming method of satellite navigation is proposed. According to matrix in- verse theorem, the range of the diagonal loading values for space-time adaptive wideband signal pro- cessing structure is deduced, and the optimum equation of diagonal loading beam forming algorithm of space-time structure is obtained. Then, by the analysis of two-dimensional oriented vector in di- rection of the perturbation interference, the wideband interference covariance matrix obtained in the weights training period is modified. Finally, the optimum weight of multi-linear constrained space- time adaptive beam-forming alogrithm is derived for anti-interference filter processing. The new method effectively widens the null steering beams tion results prove the robustness of the proposed when discrepancy happens. The computer simula- method.

2-D RAKE RECEIVER BASED ON SPACE-TIME CHANNEL PARAMETER ESTIMATION

2-D RAKE receiver is an efficient way to realize the space-time processing for CDMA systems with aperiodic spreading codes. The Direction Of Arrival (DOA) and the relative time delay of every user's multipath must be known to realize the 2-D RAKE receiver. In the third generation CDMA mobile communication system, auxiliary pilot channel is used in the uplink channels The different user's Vector Channel Impulse Response (VCIR) can be estimated from the pilotichannel easily. The VCIR contains spatial and temporal information. In this paper,by utilizing the known pulse shape function, a parameter matrix method used to estimate the Spatial Signature Vector (SSV) and the relative time delay is proposed in frequency domain.The DOA can be estimated from the SSV. By reconstructing the SSV and utilizing approximate Capon space filter, the performance of the 2-D RAKE receiver with uniform circular array can be improved with a little additional computation work.

Noncoherent Unitary Space-Time Codes： Constellation Design and Decoding Algorithm

Two novel schemes of unitary space-time constellations generation based on zero vectors adding are proposed for the multiple-antenna communication system. In the first scheme, T2 zero row vectors are added into conventional unitary matrices directly, and the number of new unitary matrices obtained by different positions of the added zero vectors in T symbol duration is [T / T2 ] times larger than that of conventional unitary matrices. In the second scheme, one part of the required constellations is created by the first scheme and the other part is obtained by the conventional design. This means that more information bits can be transmitted by the new constellations. According to their special construction, two corresponding decoding algorithms are proposed with low complexity in flat fading channel, respectively. At the same time, the probability of miss detection is deduced for the decoding algorithms. Performance analysis and simulation results show that the proposed constellations outperform the conventional constellations and the proposed decoding algorithms are efficient and simple.

四线圈原型电机模型及其空间矢量数学表征

不同类型电机的机电能量变换过程有其内在关联性,这就是“统一”电机模型理论探讨的问题。作者此前提出了“法拉第参考系”和“牵连运动电动势”概念,可实现线圈固结坐标系与运动坐标系下电压矢量方程的一致表达,并为统一电机模型理论提供了一个有效的理论方法。在此基础上,提出四线圈原型电机模型,藉此统一表征电机的机电能量变换过程。基于空间矢量数学手段,具体推导了所述原型电机模型的电压、转矩表达式,讨论了原型电机模型的基本输入、输出特性。结合理论推导证明,通过设置附加约束条件,所述原型电机模型可推广表征常见典型电机。该工作来源于教学实践,是对统一电机模型理论的有益拓展和补充;该工作对于电机工程实践也有一定参考价值,基于所给出的矢量控制架构,有望实现不同类型电机矢量控制架构的统一。

Field and reverse field solitons in waveoperator nonlinear Schrödinger equation with space-time reverse: Modulation instability

The wave-operator nonlinear Schrödinger equation was introduced in the literature.Further,nonlocal space-time reverse complex field equations were also recently introduced.Studies in this area were focused on employing the inverse scattering method and Darboux transformation.Here,we present an approach to find the solutions of the wave-operator nonlinear Schrödinger equation with space and time reverse(W-O-NLSE-STR).It is based on implementing the unified method together with introducing a conventional formulation of the solutions.Indeed,a field and a reverse field may be generated.So,for deriving the solutions of W-O-NLSE-STR,it is evident to distinguish two cases(when the field and its reverse are interactive or not-interactive).In the non-interactive and interactive cases,exact and approximate solutions are obtained.In both cases,the solutions are evaluated numerically and they are displayed graphically.It is observed that the field exhibits solitons propagating essentially(or mainly)on the negative space variable,while those of the reverse field propagate on the other side(or vice versa).These results are completely novel,and we think that it is an essential behavior that characterizes a complex field system with STR.On the other hand,they may exhibit right and left cable patterns(or vice versa).It is found that the solutions of the field and its reverse exhibit self-phase modulation by solitary waves.In the interactive case,the pulses of the field and its reverse propagate in the whole space.The analysis of modulation stability shows that,when the field is stable,its reverse is unstable or both are stable.This holds whenever the polarization of the medium is selfdefocusing.

基于可穿戴式惯性传感器的帕金森病患者运动功能自动量化研究

目的 采用可穿戴式惯性传感器采集的运动数据进行帕金森病(Parkinson’s Disease,PD)患者运动症状自动评分系统的研究,以提高疾病诊断的准确性和便捷性。方法 选取2020年5月至2021年12月在江苏省老年病医院神经内科就诊的PD患者作为研究对象。根据临床需求设计传感器采集数据的范式动作,并与统一帕金森病评分量表(Unified Parkinson’s Disease Rating Scale,UPDRS)运动评分项目建立对应关系。基于SQLite数据库,开发自动导出、自动管理的患者信息、评分与运动信号管理工具,获取平稳动作和重复性动作的特征性运动参数,探索基于支持向量机(Support Vector Machine,SVM)的自动评分模型,最终建立基于粒子群优化算法超参数优化的SVM自动评分模型。结果 使用分段参数序列组合作为输入,震颤最优准确度为0.90,平衡性最优准确度为0.87,上肢灵活性、下肢灵活性准确度分别可以达到0.83和0.81。直接使用主成分分析方法降维方法,步态最优准确度为0.78。结论 基于可穿戴式惯性传感器的PD运动功能自动量化系统与临床运动症状评估量表有较好的相关性,为临床工作带来便捷的同时,在一定程度上提高诊断的精准性,临床应用价值较高。

Classification of static spherically symmetric perfect fluid space-times via conformal vector fields in f(T)gravity

In this paper,we classify static spherically symmetric(SS)perfect fluid space-times via conformal vector fields(CVFs)in f(T)gravity.For this analysis,we first explore static SS solutions by solving the Einstein field equations in f(T)gravity.Secondly,we implement a direct integration technique to classify the resulting solutions.During the classification,there arose 20 cases.Studying each case thoroughly,we came to know that in three cases the space-times under consideration admit proper CVFs in f(T)gravity.In one case,the space-time admits proper homothetic vector fields,whereas in the remaining 16 cases either the space-times become conformally flat or they admit Killing vector fields.

统一弹塑性本构模型在ABAQUS中的开发与应用

基于统一弹塑性本构模型的有限元理论格式,根据ABAQUS的UMAT格式要求,编制相应的接口程序,将统一弹塑性本构模型引入ABAQUS中。采用退化的统一强度模型(b=0时,为Mohr-Coulomb模型)与ABAQUS自带的Mohr-Coulomb模型,对单轴试验和圆形硐室进行弹塑性分析,验证所开发材料子程序的正确性及高效性。考虑到统一强度模型的一般情况(b≠0)和屈服面硬化条件,对圆形硐室进行弹塑性计算,得到应力场的变化规律。所提出的研究思路具有普遍性,为采用ABAQUS平台进行本构模型的二次开发提供了借鉴和参考。

一种新颖的用于六相感应电机调速系统的空间矢量PWM方法

基于三相调速系统中传统的空间矢量理论和统一电压调制技术,本文提出了一种新颖的用于六相感应电机调速系统的空间矢量SVPWM方法。该方法有效地抑制了电压源逆变器供电的六相感应电机中定子谐波电流,提高了直流母线电压利用率,且易于实现,执行速度快,极易推广到以三相组为子集的多相感应电机调速系统PWM控制中。本文给出了这种SVPWM方法具体的实现思路,通过数字仿真和实验结果将它与传统的SPWM和SVPWM方法做了深入的分析和比较研究,研究结果验证了该算法的有效性,它具有谐波电流最小和实现简单的突出优点,在多相PWM逆变器控制中有广阔的应用前景。

UPFC控制方法研究

论文通过开关函数建模法确定统一潮流控制器(UPFC)的数学模型;在park变换的基础上,基于预测电流设计UPFC的d-q轴解耦控制方案。论文利用电压空间矢量脉宽调制法推导出UPFC各桥臂电力电子器件的开关状态。考虑到UPFC中间直流电容上电压控制的重要性,论文在传统PID控制的基础上,设计模糊自适应PID控制策略;MATLAB仿真结果表明,控制方案能有效地提高直流电容上电压的稳定性,改善功率波形,取得了类似扩大电容容量后的效果。系统可供同类设计参考。

影像地图集矢量要素与影像的协调处理

影像地图作为一种信息载体,其整体形象的信息价值和形式要求是不容忽视的。影像图集的统一协调性体现在很多方面,保证影像地图集的统一协调是编制高质量影像图集的基本保证,影像和矢量要素的协调处理是其中的一个重要内容。本文结合生产实践项目《广州市影像地图集》的设计制作,对图集编制过程中影像与矢量要素的统一协调处理提出了实用的设计方案。

多相电机统一SVPWM调制及无速度传感器控制实现方法研究

针对多相电机统一SVPWM调制实现问题及多相电机全阶观测器无速度传感器矢量控制的实现问题,在传统三相电机零序电压注入SPWM实现SVPWM调制的基础上,推导了多相电机统一SVPWM实现方法和多相电机矢量控制统一坐标变换理论及基于全阶观测器的无速度传感器矢量控制理论。以五相异步电机为例,研究了零序电压注入方法下的SVPWM电压利用率提高百分比、五相异步电机基于全阶观测器的无速度传感器矢量控制,并在五相异步电机实验平台上进行了实验验证。实验结果表明提出的统一SVPWM调制方法可以提高电压利用率、优化谐波性能。统一多相电机全阶观测器无速度传感器矢量控制可以实现多相电机无传感器控制、减小系统成本、提高系统可靠性。

UPFC控制器设计

分内部控制和外部控制2部分对统一潮流控制器(UPFC)进行控制器设计。内部控制采用SVPWM控制,负责提供UPFC串、并联侧电压源逆变器的触发信号,并采用一种改进的相位求解方法解决了期望输出电压矢量相位计算过程中的数值溢出问题。外部控制采用在全论域范围内带有自调整因子的变间距模糊交互控制,负责产生UPFC串、并联侧逆变器所需的控制矢量。运用Matlab仿真工具对含UPFC的单机无穷大系统进行了仿真研究。仿真结果表明所设计的UPFC可以有效地控制线路潮流、节点电压和UPFC直流侧电容电压,并且具有响应速度快、超调小、控制精度高、鲁棒性强的优点。

面向统一能源系统的中长期氢负荷预测

未来能源社会中氢气将在电力、工业、供热、交通等领域发挥巨大作用,氢能将作为统一能源系统的关键要素,实现各能源相互转化。针对未来社会中氢能在工业、供热、交通等领域的需求,提出一种氢负荷预测的方法。获取工业领域的氢负荷样本数据,算出负荷数据的特征,采用支持向量机回归(SVR)算法,得到工业领域氢负荷预测模型;然后,以供热、交通领域需氢数据建立模型,采用改进灰色GM(1,1)模型与新陈代谢模型结合,得到供热、交通领域氢负荷预测模型;最后,叠加3种氢负荷预测,完成数学模型构建。从结果可以看出SVRT预测方法十分准确、改进灰色GM(1,1)模型与新陈代谢的组合模型组预测精度较高,该方法可用于中长期氢负荷预测。

动静态特征融合的正面视角步态识别

针对正面步态识别中遇到背景颜色与人的穿着相接近或者人体下肢有阴影等情况,提出一种改进的背景减差法,利用髋关节将人体分为上下两个部分,采用分部阈值进行背景减差,提取人体二值化轮廓。对于周期检测,首先利用髋关节思想找到P点,然后利用P点找到人体左右脚最低点,并根据两脚间高低距离差所产生的角度计算步态周期并将其用于描述步态序列的动态特征;获得关键帧,并且进行归一化,分别提取它们的统一Hu矩和步态周期,用于描述步态序列的静态特征;将这两种特征进行融合,弥补了单一特征带来的识别率低的问题。最后,采用支持向量机(SVM)进行分类识别。本文的识别实验均在中科院步态数据库(CASIA)上进行训练,识别率达到97%以上。结果证明,该算法具有较好的识别速度和识别率。

统一电能质量调节器的谐波检测与补偿策略研究

统一电能质量调节器(UPQC)将串联有源滤波器和并联有源滤波器结合起来,能够同时从整体上补偿系统电流和电压,具备综合的电能质量调节功能。采用dq0谐波检测法作为UPQC的检测方法,并采用空间电压矢量SVPWM作为UPQC串联侧补偿方法,在并联侧引入自抗扰控制器ADRC,将负载电流和电网电压等系统内外部模型不确定性统一视为控制器的未知干扰,通过扩张状态观测器来估计,利用非线性反馈控制律进行补偿。此法不需要精确地测量谐波,并且能很好地适应对于不同的负荷。最后在MATLAB的Simulink软件平台上进行仿真实验,结果表明了本文所采用的检测和补偿方法的正确性和有效性。

三相三线制并联型APF控制策略的改进

针对基于矢量运算的恒频积分控制三相三线制并联型有源电力滤波器,在电源电压不对称情况下存在的问题,提出了一种改进的控制策略。通过计算相电压不对称系数,对有源电力滤波器的控制方程进行修正,使系统中各相电源电流均能跟随各相电源相电压的变化,从而实现系统单位功率因数的目标。最后对该改进策略进行仿真验证。结果表明,采用该改进策略的有源电力滤波器具有良好的补偿特性,而且该控制方案简单,开关器件损耗小。

统一电能质量控制器并联侧的改进双滞环电流控制策略研究

为提高统一电能质量控制器的电流控制策略水平,提出了一种基于最优电压空间矢量的有源电力滤波器双滞环电流控制方法。该方法先利用常规双滞环控制法,以参考电压矢量的空间分布和误差电流矢量的越界情况及所在区域为依据,给出最佳电压矢量输出,以快速控制相间误差电流。虽然该方法能保证了系统暂态过程中的响应速度,也显著降低了开关频率,但误差电流在内环时逆变器不动作导致统一电能质量控制器的补偿精确度有所降低。针对此问题,将自抗扰控制方法引入误差电流内环控制上,它将内环时系统内部模型的不确定性与系统的外部不确定性统一视为系统的未知干扰,通过扩张状态观测器来估计,然后利用非线性反馈控制律进行补偿,最后利用混沌粒子群优化算法对各个参数进行优化。该方法不需要精确地测量谐波,并且对于不同的典型负载、负荷侧电流大小和相位的变化都有很强的适应性,Matlab软件仿真和采用DSP硬件实验结果验证了所提出的电流控制方法的动静态性能和鲁棒性良好。

统一电能质量控制器容量优化设计及控制

为实现统一电能质量控制器(Unified Power Quality Conditioner,UPQC)容量在串并联单元之间的合理分配,提高UPQC补偿效率,给出了一种UPQC容量优化设计及控制方法。利用矢量图方法分析了UPQC稳态运行特性,建立了UPQC容量与电源电压暂降/骤升幅度、负载容量、负载功率因数和负载电压变化相角之间的关系模型,将其作为UPQC串并联单元容量选择的依据。根据补偿后负载电压相角可控的特点,采用神经网络对负载电压相角进行优化估计,降低UPQC实时补偿功率。仿真结果证明,所提方法能有效减小UPQC设计容量,优化动态补偿效果。