Predictive functional control of integrating process based on impulse response

The predictive model is built according to the characteristics of the impulse response of integrating process. In order to eliminate the permanent offset between the setpoint and the process output in the presence of the load disturbance, a novel error compensation method is proposed. Then predictive functional control of integrating process is designed. The method given generates a simple control structure, which can significandy reduce online computation. Furthermore, the tuning of the controller is fairly straightforward. Simulation results indicate that the designed control system is relatively robust to the parameters variation of the process.

Continuous-Time and Discrete-Time Singular Value Decomposition of an Impulse Response Function

This paper proposes the continuous-time singular value decomposition (SVD) for the impulse response function, a special kind of Green’s functions, in order to find a set of singular functions and singular values so that the convolutions of such function with the set of singular functions on a specified domain are the solutions to the inhomogeneous differential equations for those singular functions. A numerical example was illustrated to verify the proposed method. Besides the continuous-time SVD, a discrete-time SVD is also presented for the impulse response function, which is modeled using a Toeplitz matrix in the discrete system. The proposed method has broad applications in signal processing, dynamic system analysis, acoustic analysis, thermal analysis, as well as macroeconomic modeling.

WRIST FORCE SENSOR'S DYNAMIC PERFORMANCE CALIBRATION BASED ON NEGATIVE STEP RESPONSE

Negative step response experimental method is used in wrist force sensor＇s dynamic performance calibration. The exciting manner of negative step response method is the same as wrist force sensor＇s load in working. This experimental method needn＇t special experiment equipments. Experiment＇s dynamic repeatability is good. So wrist force sensor＇s dynamic performance is suitable to be calibrated by negative step response method. A new correlation wavelet transfer method is studied. By wavelet transfer method, the signal is decomposed into two dimensional spaces of time-frequency. So the problem of negative step exciting energy concentrating in the low frequency band is solved. Correlation wavelet transfer doesn＇t require that wavelet primary function be orthogonal and needn＇t wavelet reconstruction. So analyzing efficiency is high. An experimental bench is designed and manufactured to load the wrist force sensor orthogonal excitation force/moment. A piezoelectric force sensor is used to setup soft trigger and calculate the value of negative step excitation. A wrist force sensor is calibrated. The pulse response function is calculated after negative step excitation and step response have been transformed to positive step excitation and step response. The pulse response function is transferred to frequency response function. The wrist force sensor＇s dynamic characteristics are identified by the frequency response function.

Dynamic Response and Oscillating Behaviour of Fractionally Damped Beam

This paper presents the numerical solution of a viscoelastic continuous beam whose damping behaviours are defined in term of fractional derivatives of arbitrary order.Homotopy Perturbation Method(HPM)is used to obtain the dynamic response with respect to unit impulse load.Obtained results are depicted in term of plots.Comparisons are made with the analytic solutions obtained by Zu-feng and Xiao-yan(2007)to show the effectiveness and validation of the present method.

畜牧产业结构变动对生猪价格的影响

数字经济时代下,畜牧产业作为发展现代农业、促进农业经济增长的关键驱动力,对稳定我国生猪价格具有重要作用。文章基于2011年2月—2023年1月共计144个月的生猪价格数据,利用VAR模型,实证检验畜牧产业结构变动对生猪价格的影响。结果显示:畜牧产业结构变动是引起生猪价格变化的格兰杰原因;生猪价格受畜牧产业结构变动的滞后影响;生猪价格在前两期受畜牧产业结构变动的负向冲击,从第3期开始受畜牧产业结构变动的正向影响,响应程度在第12期达到峰值,在第24期影响逐渐消失;畜牧产业结构变动对生猪价格的冲击响应周期约为2年,直至第2年仍存在10.85%的贡献率。研究表明,畜牧产业结构变动对生猪价格具有正向影响作用。

大跨径钢桁架双层拱桥模态阻尼比分析方法

为有效揭示结构整体刚度的变化,解决当前模态阻尼识别准确性方面存在的突出问题,特别是在运营中的复杂桥梁结构,难以准确分离多种干扰因素,创新研究了复杂桥梁的模态阻尼比识别方法,只需有限数量的加速度传感器,即可精确且高效地分析复杂桥梁的模态阻尼比。首先,采用变分模态解耦方法,将实测的非线性振动信号准确分解为单一频率模式;其次,对这些分解后的信号应用希尔伯特变换和脉冲响应函数进行处理,从而建立模态阻尼比的求解策略;然后,选取服役中的公轨同层大跨径钢桁架双层拱桥作为实证研究对象,收集其主梁的加速度响应信号;再次,通过变分模态解耦与脉冲响应函数方法,成功分析信号特性,获取该结构的频率及阻尼比;最后,将这些频率数据与有限元模型分析结果进行比对,证实方法的准确性和可靠性。

基于VAR模型的石家庄市PM_(2.5)的影响因素研究

根据石家庄市2013年12月2日至2021年2月1日的空气污染物PM_(2.5)、PM_(10)、SO_(2)、CO、NO_(2)和O_(3)浓度数据,以及日平均气温、日平均气压、日平均相对湿度、2 min平均风速和10 min平均风速气象数据,利用向量自回归模型(Vector autoregression,VAR),从各空气污染物变量和气象变量中选取对时间序列影响较大的重要变量,研究PM_(2.5)与重要变量之间的动态关系及它们对PM_(2.5)浓度的影响。结果表明:SO_(2)浓度、NO_(2)浓度、O_(3)浓度、日平均气温、日平均气压、2 min平均风速相较其他变量对PM_(2.5)浓度有显著影响;从长期关系来看,SO_(2)浓度和日平均气压变量对PM_(2.5)浓度有正向影响,NO_(2)浓度、O_(3)浓度、日平均气温,以及2 min平均风速变量对PM_(2.5)浓度的增加有抑制作用。

宏观经济不确定性对肉羊产业链价格的影响

宏观经济不确定性是影响肉羊产业链价格的重要因素之一。以2011年6月—2022年6月肉羊产业链价格的月度数据为研究样本,利用VAR模型,通过脉冲响应函数和方差分解检验宏观经济不确定性对肉羊产业链价格的影响效应。结果表明,宏观经济不确定性有助于稳定肉羊产业链价格。宏观经济不确定性对肉羊产业链价格冲击的响应期为2年,且在第2年宏观经济不确定性对肉羊产业链价格的贡献率约为6.924 5%。因此,提出健全肉羊市场流通机制、建立肉羊产业链价格监控体系、推进适度规模化肉羊养殖的对策建议,以期推动肉羊产业可持续发展。

基于激光扫描的室内VLC光源布局设计方法

为了合理设计光源布局,提出基于激光扫描的室内可见光通信(Visible Light Communication,VLC)光源布局设计方法。应用激光扫描技术获取并处理室内信息(激光点云数据)。根据VLC信号传输特征构建链路模型,获取不同链路的脉冲响应函数。计算室内光照度,并分析光照度分布情况。构建适应度函数,通过粒子群算法循环迭代运算,获得室内VLC光源布局设计的最佳方案。实验数据显示:应用提出方法获得的光线追迹侧视图光线覆盖范围较大,均匀照明率数值超过了最小限值0.70lx,证实了提出方法应用后的光源布局更加合理。

A Stage-Structured Predator-Prey System with Impulsive Effect and Holling Type-Ⅱ Functional Response

A stage-structured predator-prey system with impulsive effect and Holling type-II functional response is investigated. By the Floquet theory and small amplitude perturbation skills, it is proved that there exists a global stable pest-eradication periodic solution when the impulsive period is less than some critical values. Farther, the conditions for the permanence of system are established. Numerical simulations are carried out to illustrate the impulsive effect on the dynamics of the system.

A Fusion Kalman Filter and UFIR Estimator Using the Influence Function Method

In this paper,the Kalman filter(KF)and the unbiased finite impulse response(UFIR)filter are fused in the discrete-time state-space to improve robustness against uncertainties.To avoid the problem where fusion filters may give up some advantages of UFIR filters by fusing based on noise statistics,we attempt to find a way to fuse without using noise statistics.The fusion filtering algorithm is derived using the influence function that provides a quantified measure for disturbances on the resulting filtering outputs and is termed as an influence finite impulse response(IFIR)filter.The main advantage of the proposed method is that the noise statistics of process noise and measurement noise are no longer required in the fusion process,showing that a critical feature of the UFIR filter is inherited.One numerical example and a practice-oriented case are given to illustrate the effectiveness of the proposed method.It is shown that the IFIR filter has adaptive performance and can automatically switch from the Kalman estimate to the UFIR estimates according to operating conditions.Moreover,the proposed method can reduce the effects of optimal horizon length on the UFIR estimate and can give the state estimates of best accuracy among all the compared methods.

MULTIPLE POSITIVE PERIODIC SOLUTIONS IN A IMPULSIVE PREDATOR-PREY SYSTEM WITH TYPEⅣFUNCTIONAL RESPONSES

The main purpose of this paper is to explore the existence of positive periodic solutions to impulsive predator-prey systems with type IV functional responses. Sufficient criteria are obtained for the existence of strictly positive periodic solutions. The approach is based on a continuation theorem in the coincidence degree theory as well as some prior estimates. This is also the first time that multiple positive periodic solutions are obtained using coincidence degree theory in impulsive ecological systems.

我国货币政策调控对产出和通胀影响的水平效应和波动率效应研究——基于VAR模型和局部投影模型冲击反应函数的实证分析

在“三重压力”下,我国货币政策调控要实现“稳增长”和“防通胀”在水平值和波动率上的“双重稳定”,既要保持适度经济增速,又要防止通货膨胀快速上升,还要防止产出和通胀波动形成的经济风险。为此,文章使用了局部投影方法和VAR模型方法计算了数量型和价格型货币政策的冲击反应函数,以此刻画货币政策对产出增长率和通货膨胀率的水平值和波动率的动态效应。实证结果表明,数量型货币政策对经济增长率和通货膨胀率均具有水平值上的显著正向效应,同时具有降低产出波动而提升通胀波动的冲击效应;价格型货币政策也对经济增长率和通货膨胀率具有显著正向效应,同时具有降低产出波动率和通胀波动率的双重稳定功能。因此,当前货币政策操作仍然要以价格型货币政策为主,以此实现货币政策逆周期和跨周期调控功能。

人口老龄化对产业结构升级的影响——基于黑龙江省的VAR分析

立足于黑龙江省的实际情况,分析人口老龄化与产业结构优化的发展现状。就人口老龄化对产业结构升级的影响进行实证分析。首先,对人口老龄化与黑龙江省产业结构高级化之间进行平稳性检验和协整检验。其次,为了更进一步地研究人口老龄化对黑龙江省产业结构升级影响的动态特征,构建VAR模型,进而进行脉冲响应分析和方差分解,探讨人口老龄化对产业结构的冲击影响并测度其在产业结构升级过程中的贡献度。

学术期刊影响因子和载文量双向互动机制再探究——以科学学与科技管理类期刊为例

以科学学与科技管理类CSSCI期刊为例,综合运用传统回归分析、分位数回归方法和脉冲响应函数,实证研究了影响因子和载文量的特殊双向互动机制。研究结果表明:影响因子对载文量同时存在正向和反向机制;但载文量对影响因子具有正向机制,反向机制并未显现;载文量对影响因子的杠杆效应大于影响因子对载文量的作用强度,且影响因子较高或较低的期刊载文量的正向弹性系数更大。根据研究结果,指出科学学与科技管理类CSSCI部分期刊载文量持续下降的现象有必要进行修正,学术期刊应以稿件质量为主,不宜为了提高影响因子,一味控制载文量。

广东省科技投入与经济增长之间的关联影响及贡献程度

为进一步深入探究广东省经济增长的真实推动因素和原因,利用2001—2020年的相关数据进行实证分析。在已有相关研究通常将科技经费投入、科技人员投入作为内生变量的基础上,遵循与研究主题密切相关、性质互斥和数据可获得性的原则,增加科技成果投入内生变量,借鉴内生增长理论构建改进的向量自回归模型(VAR),进行脉冲响应和方差分解分析。结果表明:广东省的科技投入与经济增长存在长期、稳定的螺旋式递推关系,即科技投入是推动经济增长的主要动力之一,经济增长又反过来为增加科技投入提供条件和保证;科技投入整体上对区域经济增长呈正向促进作用,其中R&D人员投入与专利申请量的正向促进作用更加稳定和持久,而R&D经费投入的正向促进作用时间相对较短;影响当期经济增长的最大因素来自上一期的经济增长,其他影响程度大小依次为R&D经费投入、R&D人员投入、专利申请量;经济增长对科技投入的贡献整体上大于科技投入对经济增长的贡献,其中对R&D人员投入推动作用表现最为突出和明显。据此,为进一步推动广东省科技投入与经济增长达到高效率的互动循环,提出改进科技经费投入方式方法、突出科技人员培养和引进、强化科技成果创造及转化等对策建议。

The Dynamics of a Predator-prey Model with Ivlev's Functional Response Concerning Integrated Pest Management

A mathematical model of a predator-prey model with Ivlev’s functional response concerning integrated pest management (IPM) is proposed and analyzed. We show that there exists a stable pest-eradication periodic solution when the impulsive period is less than some critical values. Further more, the conditions for the permanence of the system are given. By using bifurcation theory, we show the existence and stability of a positive periodic solution. These results are quite different from those of the corresponding system without impulses. Numerical simulation shows that the system we consider has more complex dynamical behaviors. Finally, it is proved that IPM stragey is more effective than the classical one.

中国能源消费量与经济增长相关性的实证研究

为探究中国化石能源消费量与经济增长的相关性,选取1965年至2020年中国第一、第二、第三产业生产总值以及煤炭、石油、天然气消费量的时间序列,通过单位根检验、建立VAR模型、格兰杰因果检验以及脉冲响应函数对上述时间序列进行统计分析。检验结果表明,第二产业与化石能源消费关系显著,第二产业的发展是引起煤炭消费的双向格兰杰原因,也是引起石油及天然气消费的单向格兰杰原因。第三产业与天然气消费关系显著,第一产业与化石能源消费无显著关系。在传统化石燃料中,对比于煤炭及石油的碳排放量,天然气的碳排放量最低,属于低碳排放化石能源,而第二产业发展与第三产业发展均是引起天然气消费的格兰杰原因。因此在未来的可持续性经济发展中,应调节能源消费结构,提高以天然气为主的低碳排放能源的使用比例,并持续推进产业结构的优化升级。

任意三角形和六边形超声阵元及其高填充率阵列的声场仿真研究

为提高超声设备中二维相控阵列聚焦换能器的面积填充率,提升聚焦区域的超声能量和治疗效率,本研究利用空间脉冲响应理论对任意三角形阵元进行声场计算,通过对三角形阵元进行二维平面旋转完成了六边形阵元声场仿真,并通过对六边形阵元进行三维空间旋转实现了球面阵列聚焦换能器声场仿真。仿真结果显示,六边形7阵元球面填充率提高了6.1%,其-6 dB焦域横向宽度为2.0 mm、纵向长度为30.1 mm;19阵元球面填充率提高了5.5%,其-6 dB焦域横向宽度为1.2 mm、纵向长度为9.8 mm,可实现高精度超声治疗。本研究可为任意三角形和六边形及不规则形状阵元声场仿真提供新方法,且为高填充率的球面聚焦超声换能器设计提供新思路。

企业研发机构规模对企业创新的影响效应

企业研发机构是全面提高企业自主创新能力的中坚力量,但现有相关研究更多集中在企业规模与企业创新的关系上,较少关注企业研发机构规模与企业创新之间的互动关系。为此,选取2013—2020年我国29个省份的高技术企业的相关面板数据,采用联立方程模型、面板门槛模型和面板向量自回归模型对其研发机构规模与企业创新之间的静态线性关系、静态非线性关系和动态关系进行分析,并选用反向传播人工神经网络进行稳健性检验,以及运用脉冲响应函数和方差分解进一步分析企业创新、研发机构规模、研发经费投入、研发劳动力投入的脉冲响应。结果表明:企业研发机构规模与企业创新之间不存在显著静态线性关系;随着企业研发机构规模扩大,其对企业创新影响的弹性逐渐降低;随着企业创新成果水平的提高,企业研发机构规模对企业创新影响的弹性增大;企业研发机构规模扩大实际会在滞后1期时对企业创新产生最大的正向作用,且持续性不强,而企业创新对企业研发机构规模存在负向影响,说明当企业达成现阶段的创新目标后,大多不再进行大规模的创新,甚至适当削减其研发机构规模。