The nonlinear resonance response of an electrostatically actuated nanobeam is studied over the near-half natural frequency with an axial capacitor controller. A graphene sensor deformed by the vibrations of the nanobe...The nonlinear resonance response of an electrostatically actuated nanobeam is studied over the near-half natural frequency with an axial capacitor controller. A graphene sensor deformed by the vibrations of the nanobeam is used to produce the voltage signal. The voltage of the vibration graphene sensor is used as a control signal input to a closed- loop circuit to mitigate the nonlinear vibration of the nanobeam. An axial control force produced by the axial capacitor controller can transform the frequency-amplitude curves from nonlinear to linear. The necessary and sufficient conditions for guaranteeing the system stability and a saddle-node bifurcation are studied. The numerical simulations are conducted for uniform nanobeams. The nonlinear terms of the vibration system can be transformed into linear ones by applying the critical control voltage to the system. The nonlinear vibration phenomena can be avoided, and the vibration amplitude is mitigated evidently with the axial capacitor controller.展开更多
A novel nonlinear mirror structure which can increase the optical signal-to-noise ratio of a distributed fiber Raman temperature sensor is proposed, and 6 dB improvement of the optical signal-to-noise ratio is obtaine...A novel nonlinear mirror structure which can increase the optical signal-to-noise ratio of a distributed fiber Raman temperature sensor is proposed, and 6 dB improvement of the optical signal-to-noise ratio is obtained. With the assistance of the nonlinear mirror, we demonstrate that the spatial resolution of the sensor is improved from 3 m to 1 m, and the temperature accuracy is improved from ±0.6℃ to ±0.2℃. The theoretical analysis and the experimental data are in good agreement.展开更多
This paper is concerned with the recursive filtering problem for a class of discrete-time nonlinear stochastic systems in the presence of multi-sensor measurement delay. The delay occurs in a multi-step and asynchrono...This paper is concerned with the recursive filtering problem for a class of discrete-time nonlinear stochastic systems in the presence of multi-sensor measurement delay. The delay occurs in a multi-step and asynchronous manner, and the delay probability of each sensor is assumed to be known or unknown. Firstly, a new model is constructed to describe the measurement process, based on which a new particle filter is developed with the ability to fuse multi-sensor information in the case of known delay probability.In addition, an online delay probability estimation module is introduced in the particle filtering framework, which leads to another new filter that can be implemented without the prior knowledge of delay probability. More importantly, since there is no complex iterative operation, the resulting filter can be implemented recursively and is suitable for many real-time applications. Simulation results show the effectiveness of the proposed filters.展开更多
Ten physical and environmental variables collected from an on-the-go soil sensor at two field sites (MF3E and MF11S) in Mississippi, USA, were analyzed to assess soil variability and the interrelationships among the m...Ten physical and environmental variables collected from an on-the-go soil sensor at two field sites (MF3E and MF11S) in Mississippi, USA, were analyzed to assess soil variability and the interrelationships among the measurements. At MF3E, moderate variability was observed in apparent electrical conductivity shallow (ECas), slope, and ECa ratio measurements, with coefficients of variation ranging from 20% to 27%. In contrast, MF11S exhibited higher variability, particularly in ECas and ECad (deep) measurements, which exceeded 30% in their coefficient of variation values, indicating significant differences in soil composition and moisture content. Correlation analysis revealed strong positive relationships between the near-infrared-to-red ratio and red reflectance (r = 0.897***) soil values at MF3E. MF11S demonstrated a strong negative correlation between ECas and ECad readings with the x-coordinate (r ***). Scatter plots and fitted models illustrated the complexity of relationships, with many showing nonlinear trends. These findings emphasize the need for continuous monitoring and advanced modeling to understand the dynamic nature of soil properties and their implications for agricultural practices. Future research should explore the underlying mechanisms driving variability in the soil characteristics to enhance soil management strategies at the study sites.展开更多
In order to solve the problem that the traditional radial basis function (RBF) neural network is easy to fall into local optimal and slow training speed in the data fusion of multi water quality sensors, an optimizati...In order to solve the problem that the traditional radial basis function (RBF) neural network is easy to fall into local optimal and slow training speed in the data fusion of multi water quality sensors, an optimization method of RBF neural network based on improved cuckoo search (ICS) was proposed. The method uses RBF neural network to construct a fusion model for multiple water quality sensor data. RBF network can seek the best compromise between complexity and learning ability, and relatively few parameters need to be set. By using ICS algorithm to find the best network parameters of RBF network, the obtained network model can realize the non-linear mapping between input and output of data sample. The data fusion processing experiment was carried out based on the data released by Zhejiang province surface water quality automatic monitoring data system from March to April 2018. Compared with the traditional BP neural network, the experimental results show that the RBF neural network based on gradient descent (GD) and genetic algorithm (GA), the new method proposed in this paper can effectively fuse the water quality data and obtain higher classification accuracy of water quality.展开更多
实际化工工业过程数据往往存在多重共线性、高度非线性等多重特性,这会严重影响传统软测量模型对关键质量变量的预测精度。针对这一局限性,提出了一种分布式非线性映射和并行输入的双向长短记忆(distributed nonlinear mapping and para...实际化工工业过程数据往往存在多重共线性、高度非线性等多重特性,这会严重影响传统软测量模型对关键质量变量的预测精度。针对这一局限性,提出了一种分布式非线性映射和并行输入的双向长短记忆(distributed nonlinear mapping and parallel input bidirectional long short-term memory,DNMPI-BiLSTM)软测量模型。在所提策略中,首先为了阐述过程变量与质量变量之间的关联性,采用互信息以及最大相关最小冗余方法对输入数据集进行分类。随后,为了充分挖掘工业过程内部所包含的高度复杂的非线性关系,利用深度极限学习机的隐藏层对子过程变量空间进行非线性映射到高维空间。最后,将三类数据的非线性映射结果并行,建立了基于分布式非线性映射和并行输入的DNMPI-BiLSTM软测量模型,以提升模型对复杂工业过程质量变量的预测能力。通过三个工业案例验证所提方法的有效性,仿真结果表明,所提出的基于分布式非线性映射和并行输入的BiLSTM软测量建模方法的预测精度优于其他先进模型。展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.51275280 and51575325)
文摘The nonlinear resonance response of an electrostatically actuated nanobeam is studied over the near-half natural frequency with an axial capacitor controller. A graphene sensor deformed by the vibrations of the nanobeam is used to produce the voltage signal. The voltage of the vibration graphene sensor is used as a control signal input to a closed- loop circuit to mitigate the nonlinear vibration of the nanobeam. An axial control force produced by the axial capacitor controller can transform the frequency-amplitude curves from nonlinear to linear. The necessary and sufficient conditions for guaranteeing the system stability and a saddle-node bifurcation are studied. The numerical simulations are conducted for uniform nanobeams. The nonlinear terms of the vibration system can be transformed into linear ones by applying the critical control voltage to the system. The nonlinear vibration phenomena can be avoided, and the vibration amplitude is mitigated evidently with the axial capacitor controller.
基金supported by the National Natural Science Foundation of China under Grant No.60377021partially supported by Program for New Century Excellent Talents in University under Grant No. NCET-07-0152Sichuan Scientific Funds for Young Researchers under Grant No. 08ZQ026-012.
文摘A novel nonlinear mirror structure which can increase the optical signal-to-noise ratio of a distributed fiber Raman temperature sensor is proposed, and 6 dB improvement of the optical signal-to-noise ratio is obtained. With the assistance of the nonlinear mirror, we demonstrate that the spatial resolution of the sensor is improved from 3 m to 1 m, and the temperature accuracy is improved from ±0.6℃ to ±0.2℃. The theoretical analysis and the experimental data are in good agreement.
基金supported by the National Natural Science Foundation of China(6147322711472222)+3 种基金the Fundamental Research Funds for the Central Universities(3102015ZY001)the Aerospace Technology Support Fund of China(2014-HT-XGD)the Natural Science Foundation of Shaanxi Province(2015JM6304)the Aeronautical Science Foundation of China(20151353018)
文摘This paper is concerned with the recursive filtering problem for a class of discrete-time nonlinear stochastic systems in the presence of multi-sensor measurement delay. The delay occurs in a multi-step and asynchronous manner, and the delay probability of each sensor is assumed to be known or unknown. Firstly, a new model is constructed to describe the measurement process, based on which a new particle filter is developed with the ability to fuse multi-sensor information in the case of known delay probability.In addition, an online delay probability estimation module is introduced in the particle filtering framework, which leads to another new filter that can be implemented without the prior knowledge of delay probability. More importantly, since there is no complex iterative operation, the resulting filter can be implemented recursively and is suitable for many real-time applications. Simulation results show the effectiveness of the proposed filters.
文摘Ten physical and environmental variables collected from an on-the-go soil sensor at two field sites (MF3E and MF11S) in Mississippi, USA, were analyzed to assess soil variability and the interrelationships among the measurements. At MF3E, moderate variability was observed in apparent electrical conductivity shallow (ECas), slope, and ECa ratio measurements, with coefficients of variation ranging from 20% to 27%. In contrast, MF11S exhibited higher variability, particularly in ECas and ECad (deep) measurements, which exceeded 30% in their coefficient of variation values, indicating significant differences in soil composition and moisture content. Correlation analysis revealed strong positive relationships between the near-infrared-to-red ratio and red reflectance (r = 0.897***) soil values at MF3E. MF11S demonstrated a strong negative correlation between ECas and ECad readings with the x-coordinate (r ***). Scatter plots and fitted models illustrated the complexity of relationships, with many showing nonlinear trends. These findings emphasize the need for continuous monitoring and advanced modeling to understand the dynamic nature of soil properties and their implications for agricultural practices. Future research should explore the underlying mechanisms driving variability in the soil characteristics to enhance soil management strategies at the study sites.
文摘In order to solve the problem that the traditional radial basis function (RBF) neural network is easy to fall into local optimal and slow training speed in the data fusion of multi water quality sensors, an optimization method of RBF neural network based on improved cuckoo search (ICS) was proposed. The method uses RBF neural network to construct a fusion model for multiple water quality sensor data. RBF network can seek the best compromise between complexity and learning ability, and relatively few parameters need to be set. By using ICS algorithm to find the best network parameters of RBF network, the obtained network model can realize the non-linear mapping between input and output of data sample. The data fusion processing experiment was carried out based on the data released by Zhejiang province surface water quality automatic monitoring data system from March to April 2018. Compared with the traditional BP neural network, the experimental results show that the RBF neural network based on gradient descent (GD) and genetic algorithm (GA), the new method proposed in this paper can effectively fuse the water quality data and obtain higher classification accuracy of water quality.
文摘实际化工工业过程数据往往存在多重共线性、高度非线性等多重特性,这会严重影响传统软测量模型对关键质量变量的预测精度。针对这一局限性,提出了一种分布式非线性映射和并行输入的双向长短记忆(distributed nonlinear mapping and parallel input bidirectional long short-term memory,DNMPI-BiLSTM)软测量模型。在所提策略中,首先为了阐述过程变量与质量变量之间的关联性,采用互信息以及最大相关最小冗余方法对输入数据集进行分类。随后,为了充分挖掘工业过程内部所包含的高度复杂的非线性关系,利用深度极限学习机的隐藏层对子过程变量空间进行非线性映射到高维空间。最后,将三类数据的非线性映射结果并行,建立了基于分布式非线性映射和并行输入的DNMPI-BiLSTM软测量模型,以提升模型对复杂工业过程质量变量的预测能力。通过三个工业案例验证所提方法的有效性,仿真结果表明,所提出的基于分布式非线性映射和并行输入的BiLSTM软测量建模方法的预测精度优于其他先进模型。
