Fuzzy Adaptive Control of Stochastic Nonlinear Systems with Unknown Virtual Control Gain Function

The problem of track control is studied for a class of strict-feedback stochastic nonlinear systems in which unknown virtual control gain function is the main feature. First, the so-called stochastic LaSalle theory is extended to some extent, and accordingly, the results of global ultimate boundedness for stochastic nonlinear systems are developed. Next, a new design scheme of fuzzy adaptive control is proposed. The advantage of it is that it does not require priori knowledge of virtual control gain function sign, which is usually demanded in many designs. At the same time, the track performance of closed-loop systems is improved by adaptive modifying the estimated error upper bound. By theoretical analysis, the signals of closed-loop systems are globally ultimately bounded in probability and the track error converges to a small residual set around the origin in 4th-power expectation.

Is Gain of Function a Reliable Tool for Establishing Sars-Cov-2 Origin?

The present opinion article, while dealing with the debated origin of “Severe Acute Respiratory Syndrome-Coronavirus-2” (SARS-CoV-2), the betacoronavirus responsible for “Corona Virus Disease-2019” (COVID-19), provides a speculative insight into the so-called “gain of function” (GOF), a process resulting in the acquirement of new phenotypic features on behalf of the viral pathogen. More in detail, a GOF-related phenomenon leading to increased SARS-CoV-2 virulence and/or transmissibility—as clearly exemplified by the “delta” and the “omicron” as well as by other “variants of concern”—would not necessarily imply that viral genetic manipulations made in the laboratory are its exclusive drivers, provided that GOF may also occur as a consequence of a natural selection process. In order to gain a better understanding of SARS-CoV-2 GOF and GOF-associated phenomena, an in-depth knowledge of the complex viral-host interaction dynamics is absolutely needed, while also paying special attention to the human-animal-viral ecological interfaces within an “ad hoc” multidisciplinary, “holistic”, scientific evidence-based and “One Health”-based approach.

基于双重约束的并网逆变器电流自动化控制方法研究

为降低并网逆变器逆变的并网电流畸变率,提出基于双重约束的并网逆变器电流自动化控制方法。以典型的三相LCL并网逆变器为例,分析其运行状态;并确定并网逆变器在进行逆变转换时,谐波对于逆变器并网电流的影响,计算并网逆变器环路增益函数;采用输出电流直接前馈的改进阻尼控制方法实现电流自动化控制,并引入全局-局部稳定双重约束原则,确定最佳的谐振抑制参数,提升电流的控制效果。测试结果显示,该方法的并网逆变器的电流畸变率均低于5%,电流跳变过程中,可在0.2 s内有效控制跳变电流结果。

基于深度神经网络的多聚焦红外图像非线性增强

当红外图像中含有多个聚焦目标主体时,会导致红外图像质量下降,部分区域出现模糊,因此,提出基于深度神经网络的多聚焦红外图像非线性增强方法。在引导滤波的作用下,从红外图像中获取细节层图像和背景层图像,在细节层图像中建立局部清晰度评价函数,得到清晰的细节层和背景层并融合二者。利用构建的深度神经网络结构,建立非线性增益函数,通过设定阈值和调整子带系数,实现对多聚焦红外图像的非线性增强。测试结果表明,所提方法在增强图像过程中,并没有改变原始图像的亮度和纹理波动;增强后的图像信息熵比原图像提高了57%左右,图像抗噪性能值更高,平均为7.4 dB,图像更清晰,SSIM值更趋近于1,平均为0.98,增强后的图片与原图片图像相似度更高,更接近于真实图像。

基于变增益NDOB的异步电机分段积分滑模控制

为改进异步电机的动态性和鲁棒性,设计了一种新型的滑模控制方法。首先,滑模面引入平滑的分段饱和函数,改进传统的积分滑模控制,在传统积分滑模控制的跟踪精度下,获得更好的暂态性能;其次,采用了一种超扭曲类算法的新型趋近律,削弱了系统的抖振,提高系统的稳态性能;最后,设计变增益非线性扰动观测器,可消除初始时刻观测器峰值,准确估计因模型不确定性、负载扰动等集总扰动。通过与传统积分滑模控制器对比,实验结果证明该方法具有更好的快速性与稳定性。

基于RBFNN的智能车辆转向系统的预设性能控制

针对存在模型非线性和参数不确定性的智能车辆转向系统的预设性能跟踪控制问题,采用径向基函数神经网络对转向系统中的不确定非线性进行在线逼近,结合障碍Lyapunov函数技术为智能车辆的线控转向系统设计预设性能控制器。在控制器设计中,采用动态增益技术补偿控制增益未知对系统控制性能的影响。利用Lyapunov方法分析系统的稳定性,证明在控制器作用下,前轮转角的跟踪误差在预设的时间内收敛至原点预设的邻域;通过数值仿真和整车实验验证了控制方法的合理性。

基于SMO的永磁同步电机抖振分析及其改进

针对传统基于SMO的永磁同步电机系统中存在抖振较大、观测精度差的问题,在传统SMO基础上,引入了自适应增益替代固定增益,采用双曲正切函数代替传统开关函数,提出了改进型SMO控制策略。在MATLAB/Simulink平台构建了系统仿真模型,对控制策略的效果进行验证并分析。结果表明:改进后的SMO控制策略显著减小了电机抖振,具备较高的转子位置估计精度。

非均匀当量比对旋转爆震燃烧室性能影响的三维数值模拟研究

为研究入口当量比的不均匀分布对旋转爆震燃烧室性能的影响,建立了当量比在入口环缝的径向或周向的函数模型,将模型公式代入组分质量分数与当量比的关系式,得到组分质量分数在径向或周向的分布函数。通过Fluent软件中的自定义函数工具,构造入口边界组分的分布函数,利用三维瞬态欧拉方程模拟了C_(10)H_(22)/air旋转爆震燃烧室中爆震波的传播过程及流场特性,对比了不同当量比分布下爆震波及旋转爆震燃烧室性能参数的变化特征。结果表明:入口当量比的不均匀分布会影响爆震波的传播特性;当量比为0.4~1.6且沿径向非均匀分布时,随着入口面中线位置当量比的增大,爆震波的高度减小;当量比为0.4~1.6且沿周向非均匀分布时,随着变化周期数的增加,爆震波的高度几乎不受影响;当量比的不均匀分布会削弱旋转爆震燃烧室的增压效果和温升效果,沿径向不均匀分布的情况相较于沿周向不均匀分布的情况,影响更明显;旋转爆震燃烧室内,爆震波的诱导和反应区并非严格位于前导激波的正后方,而是位于前导激波的斜后方,且在曲率的影响下,在靠近燃烧室外壁面的区域,前导激波沿中径圆柱面的圆周线传播。

基于改进SMO与变参数LTD的PMSM无传感器控制

为解决基于滑模观测器的PMSM无感控制系统抖振大、响应速度慢等问题,在转速环PI控制器前引入变参数线性跟踪微分器,实现由I/F起动向转速-电流双闭环控制模式的平稳过渡。采用sigmoid函数替换sign函数消除由sign函数在滑模面切换给等效反电动势带来的高次谐波;根据反电动势与电机转速关系以自适应滑模增益提高系统响应速度,并利用李雅普诺夫稳定性判据分析改进后算法稳定性。在仿真平台以及PMSM控制系统上进行控制算法验证,表明了所提出的改进PMSM无传感器控制策略对抑制系统抖振与提高系统的响应速度具有良好的效果。

Anti-windup Compensator Gain Design for Time-delay Systems with Constraints

Systems that are subject to both time-delay in state and input saturation are considered. We synthesize the anti-windup gain to enlarge the estimation of domain of attraction while guaranteeing the stability of the closed-loop system. An ellipsoid and a polyhedral set are used to bound the state of the system, which make a new sector condition valid. Other than an iterative algorithm, a direct designing algorithm is derived to compute the anti-windup compensator gain, which reduces the conservatism greatly. We analyze the delay-independent and delay-dependent cases, respectively. Finally, an optimization algorithm in the form of LMIs is constructed to compute the compensator gain which maximizes the estimation of domain of attraction. Numerical examples are presented to demonstrate the effectiveness of our approach.

Effect of body mass index on functional outcomes following arthroplasty procedures

AIM: To evaluate the body mass index(BMI) change in arthroplasty patients and its impact on the patients' functional results. METHODS: Between October 2010 and May 2013, 606 patients who were operated due to gonarthrosis, coxarthrosis, aseptic loosening of the total knee and hip prosthesis were evaluated prospectively. Patients were operated by three surgeons in three medical centers. Patients who were between 30-90 years of age and who were underwent total knee arthroplasty, total hip arthroplasty, revision knee arthroplasty, or revision hip arthroplasty were included in the study. We excluded the patients who cannot tolerate our standard postoperative rehabilitation program. Additionally, patients who had systemic inflammatory diseases, diabetes mellitus, or endochrinopathies were excluded from the study. The remaining 513 patients comprised our study group. Preoperative functional joint scores, height, weightand BMI of all patients were recorded. We used the Knee Society Score(KSS) for knee and Harris Hip Score(HHS) for hip patients. Postoperative functional scores were measured at 1^(st), 6^(th) and 12^(th) months and recorded separately at outpatient visits. RESULTS: The mean age of the patients was 64.7(range: 30-90) years(207 males/306 females) and the mean follow-up duration was 14.3(range: 12-26) mo. We found that arthroplasty patients had weight gain and had an increase in BMI at the postoperative 1^(st), 6^(th) and 12^(th) months. The mean BMI of the patients was 27.7 preoperatively, 27.8 at the postoperative 1^(st) month, 28.1 at the 6^(th) month and 28.6 at the 12^(th) month(P < 0.01). At the last visit, the mean postoperative HHS of the hip arthroplasty patients was 82.2 ± 7.12(preoperatively, 52.3; 1st month, 78.2; 6^(th) month, 81.1; 12^(th) month, 82.2), and the mean KSS of the knee arthroplasty patients was 79.3 ± 4.31(preoperatively, 35.8; 1^(st) month, 75.2; 6^(th) month, 79.1; 12^(th) month, 79.3). Worse functional results were noted in the patients who had a BMI increase, however, this correlation was statistically significant only at the postoperative 6^(th) month(P = 0.03). CONCLUSION: To prevent the negative functional effects of this weight gain during the postoperative period, arthroplasty patients should be advised for weight control and risky patients should consult with a dietician.

A Traceable Cancer Model: DNA Damage, Fragile Site-SMGs, Mitotic Slippage, 4n-Genome-Reduction to Fitness-Gained, Initiating, 2n First Cells

We have known since 1976 that cancer evolves clonally from one initiated normal human cell, the first cell. Today we see that this fact has been overshadowed from federal funding choice of the mutation theory (MT), which not yet has shown tumorigenesis-initiation in normal human cells. Our suggested, death signaled, stress model from time delayed S-period (replication slowness), causing repair instability from under-replicated lesions in repetitive DNAs, herein has the objective of revealing, significant literature support from a mini-review. We reasoned that early versus late S-period stress would have different outcomes: early the slowness affecting mitotic slippage with diploid re-replication to 4n cells whereas late-S, with milder stress effect, producing diploid cells. In cancer burden, near-half is diploid, but tetraploid solid tumors have the attention. The initial 4n cells were special with orderly genomic reductive division to diploid first cells with measurable fitness-gain from hours-reduced total cell cycle time. Experimental data from Coxsakie-B3 virus infected normal fibroblasts, reiterated 4n cell production from death-signaled recovery-cells with progressive cell-phenotypic changes to polygonal and roundness cell-shapes, indistinguishable from diagnostic/prognostic cancer morphology. The 4n cells showed a self-inflicted 90° turn of the 4n nucleus before division, affecting a perpendicular orientation of the fitness-gained first cells relative to neighboring cells. In an illustrated cell cycle drawing with early and late S-period stress, it became clear that coding genes on borders of repair unstable satellite, repetitive DNA regions, could become mutated. We found these mutations to be tumor SMGs (significantly mutated genes). Evidential material was presented for loss of function genetics driving tumorigenesis to a parasitic lifestyle.

基于滑模的三维Coullet系统鲁棒控制

研究三维Coullet系统的鲁棒控制问题.首先,通过绘制系统时域波形图、混沌吸引子图和Lyapunov指数图验证系统复杂的动力学行为;其次,分别用滑模控制方法、基于滑模的高频鲁棒控制方法和高增益鲁棒控制方法设计控制器,并对系统进行控制;最后,通过数值仿真验证控制器的有效性.

Na_(2)高振动态与CO_(2)间碰撞转移概率分布的实验测量

受激发射泵浦激发Na_(2)至Na_(2)(ν″=30,J″=11)和Na_(2)(ν″=45,J″=11)。Na_(2)(ν″)与CO_(2)碰撞,研究了CO_(2)(00~00)的全态可分辨转动分布及不同的Na_(2)振动能对碰撞猝灭动力学的影响。光学吸收法测量Na_(2)(ν″)与CO_(2)碰撞后的弛豫过程,在一次碰撞的条件下,确定了ν″,ν″-1及ν″-2各振动能级上的转动态分布,而高于ν″的振动能级没有观察到,从而得到碰撞过程中Na_(2)转动能的改变。在碰撞发生1μs后,测量CO_(2)低J态的瞬时线轮廓,利用双Guass函数拟合,得到两个Doppler增宽轮廓,一个是存在于J态粒子的Doppler半宽,一个是被碰撞出J态粒子的Doppler半宽。从存在于J态的Doppler半宽,得到在Na_(2)(ν″)/CO_(2)碰撞中质心平移速度,从而确定平均平移能的增加〈ΔE_(rel)〉。Na_(2)(ν″)振动能的增加与CO_(2)平动能的增加有很大关系,Na_(2)振动能增加35%,而平动能增加56%。从CO_(2)的其他转动态碰到J态的出现速率系数k^(J)_(app)由测量碰撞前和碰撞1μs后的泛频激光感应荧光强度得到总的出现速度系数k_(app)=Σ_(J)k_(app)^(J)=(6.6±1.5)×10^(-10)cm^(3)·molecule^(-1)·s^(-1)[对Na_(2)(ν″=30)]和(5.9±1.3)×10^(-10) cm^(3)·molecule^(-1)·s^(-1)[对Na_(2)(ν″=45)]。因此Na_(2)(ν″)/CO_(2)的碰撞频率对Na_(2)的振动能不是很敏感的。取k_(app)作为参考速率系数,得到了全部能量转移概率分布P(ΔE),这里的ΔE包括了CO_(2)转动能和平动能的变化以及Na_(2)转动能的变化,对于Na_(2)分子振动能的较小增加,会引起P(ΔE)曲线的迅速增宽,在ΔE>500 cm^(-1)以后,Na_(2)(ν″=30)/CO_(2)的P(ΔE)曲线移到了Na_(2)(ν″=45)/CO_(2)的P(ΔE)曲线的下面。P(ΔE)对ΔE在0~3 000 cm^(-1)之间的数值积分给出〈ΔE〉_(trans)=590 cm^(-1)[对Na_(2)(ν″=30)],而对Na_(2)(ν″=45)则给出〈ΔE〉_(trans)=880 cm^(-1)。

双馈风机传递函数的分数阶模型辨识近似

双馈风机转子电磁转矩的传递函数增益动态行为比较复杂,用整数阶模型分析时使用的变量多。分数阶模型作为传统整数阶模型的扩展,具有模型变量少、动态行为分析简单的优势。首先,结合分数阶的辨识理论,根据不同的目的需求,提出双馈风机转子电磁转矩传递函数增益的2q阶分数阶模型和3q阶分数阶模型;然后,基于整数阶频域响应数据,运用基于Levy的改进辨识算法实现分数阶模型的参数辨识,并加入权重函数以改善分数阶模型在低频段下的拟合度;最后,在算例中,对比分析两种分数阶模型与辨识模型的动态特性,通过Bode图对比分析和均方差指标,验证了辨识近似方法在频域中的有效性;单位阶跃响应曲线验证了分数阶模型暂态过程的有效性。

MIMO系统中基于代价函数和排序模式的MMSE SIC检测器

针对多输入多输出空间多路复用系统,提出了一种基于代价函数和排序模式的多个并行分支的最小均方误差连续干扰消除检测器;具体而言,设计了选择规则来选择代价函数性能最好的分支,并通过利用不同的检测排序模式使得每个分支中的SIC算法按照信号干扰噪声比由高到低来检测信号,从而实现完全检测分集;为了进一步降低算法的计算复杂度,还提出了一种采用递归最小二乘算法的有效自适应接收机来更新滤波器权值向量,从而获得基于递归最小二乘算法的MB-SIC接收机的自适应实现;此外,还对提出的检测器在比特差错概率性能方面进行了分析;仿真结果表明,相比于现有的检测算法,提出的算法不仅具有较低的计算复杂度,而且能获得更好的误码率性能。

非线性互联系统状态观测器设计方法研究

非线性互联系统广泛应用于各类工业生产中。随着科学技术的迅速发展,控制系统的复杂程度越来越高,同时各子系统之间的互联性也变得越来越强。因此,针对日益复杂的非线性互联系统进行研究,已成为一个非常重要的课题。针对非线性互联系统观测器的设计方法进行研究,通过设计状态观测器实现对互联系统中状态向量的鲁棒估计。首先,基于李雅普诺夫函数给出广义互联系统状态观测器存在的充分条件。其次,将非线性广义互联系统观测器的存在条件进行推广,得到正常非线性互联系统观测器存在的充分条件。观测器的存在条件均通过Schur补引理,以线性矩阵不等式的形式给出,简化了观测器增益矩阵的求解,得到了互联系统观测器的设计方法。最后,利用MATLAB软件计算出观测器的增益矩阵。两个算例仿真结果验证了所提方法的可行性与有效性。

巴特沃斯高通滤波器的优化设计与仿真实现

为了高效设计出性能良好并且网络参数较易选择的通用型高通滤波器,首先理论分析了压控电压源式滤波电路,在此基础上推导不同增益下的二阶高通滤波器的表达式,然后将理论推导的两个二阶高通滤波器进行分别级联,设计了两个四阶巴特沃斯高通滤波器,最后通过Multisim14.0对两个四阶巴特沃斯高通滤波器进行仿真,并用Origin2019进行数据整理。仿真实验结果表明基于不同增益下二阶高通滤波器设计的两个四阶巴特沃斯高通滤波器均具有较好的幅频特性,并且幅频特性曲线接近重合。证明所提方法可用于快速设计性能良好的高通滤波器。

基于效用函数的无源光网络动态带宽分配算法

为解决无源光网络由于传播距离较远而导致传播时延较长、信道利用率较低的问题,提出一种基于效用函数的无源光网络动态带宽分配算法。在无源光网络上行数据传输方向上,凭借光线路终端规律性地轮询各光分配网,获取上行带宽的请求信息。在无源光网络下行数据传输方向上,光线路终端把光网络的下行业务分组装入帧,并以广播的形式进行数据传输,结合此特点,利用带宽分配与微观经济学之间的相似度。以传输功率和传输信号增益,建立基于效用函数的分配问题优化模型,并通过路由器矩阵及其逆矩阵对该问题模型进行求解,得出各链路的最优传输速率,实现无源光网络动态带宽分配。实验结果表明,所提算法的信道利用率较高且时延抖动较低,能够有效提升网络动态实时性。

PIK3CD功能获得性突变致慢性EB病毒感染1例并文献复习

目的报道1例PIK3CD基因功能获得性(GOF)突变致慢性EB病毒(EBV)感染患儿,探讨该病临床表现及基因突变特点。方法收集患儿的临床资料,提取患儿及直系亲属外周血DNA,通过全外显子组测序技术检测其基因突变情况,并检索相关文献进行复习。结果患儿自2岁始反复出现呼吸道感染,伴肝脾淋巴结肿大,反复出现种痘样皮疹;血清EBV抗体水平显著升高,淋巴组织活检提示T淋巴细胞增殖性改变,EBV编码RNA(EBER)阳性。13岁时患儿血液中免疫球蛋白水平显著升高伴多种自身抗体阳性。基因检测提示PIK3CD基因杂合突变c.3061G>A(p.E1021K),文献复习提示该突变为GOF突变。结论PIK3CD基因GOF突变可导致EBV易感及EBV慢性感染,临床表现为淋巴组织增生、特征性皮疹出现。该病患儿亦可表现为血液中免疫球蛋白水平的显著升高,可能与自身免疫反应所致自身抗体大量形成有关。