In order to explore the cell composition and its metabolism,it is important to let computer recognize the cells and get the counts of different cells for a sample.This paper proposes an L-shaped envelop function and t...In order to explore the cell composition and its metabolism,it is important to let computer recognize the cells and get the counts of different cells for a sample.This paper proposes an L-shaped envelop function and the related fuzzy clustering method as a way to identify the megakaryocyte and the red cell from the sliced marrow image.This method is useful when the staining is insufficient and the color cannot be used as the identifying factor.This method uses the experimental histogram data to fit the L-shaped function and then use it as the envelop for the match test.The fuzzy c-means(FCM) performance index is used to test the adjacent area and get the minimum and finally secure the identification.The new method is not limited to megakaryocyte or red cell and can be used for general purposes of cell recognition.Tests show that this envelop function can ensure the recognition rate with different staining batches and can reach satisfied counting under similar illumination condition.展开更多
After the time history of seismic motion is represented by superposition of a series of narrow frequency band wave groups, we obtain a general relation between wave group arrival time and derivative of phase spectra i...After the time history of seismic motion is represented by superposition of a series of narrow frequency band wave groups, we obtain a general relation between wave group arrival time and derivative of phase spectra in the paper. On the basis of the relation, frequency number distribution function of wave group arrival time is completely equivalent to that of phase difference spectra. Under the assumption that phase angles of seismic motionobey uniform distribution ranged from 0 to ─ 2π, a quantitative relation between intensity envelope function of seismic motion and energy distribution function with wave group arrival time has been derived in this paper. The relation illuminates inner links among Fourier amplitude spectra and derivative of phase spectra and intensity envelope function. Some examples given by the paper support the conclusions mentioned above.展开更多
It has been a period of time since the concept of scenario earthquake was proposed, but this concept has rarely been used in seismic safety evaluation in China since then. Meanwhile, because of the uncertainties of ma...It has been a period of time since the concept of scenario earthquake was proposed, but this concept has rarely been used in seismic safety evaluation in China since then. Meanwhile, because of the uncertainties of magnitudes-distances pairs, there is large arbitrariness while determining the envelope function of time histories in seismic hazard analysis. In this paper, we describe a method to control the envelope functions of the time histories by introducing the most-likely combinations of magnitude and distance of the scenario earthquakes based on a probabilistic method, revise the software of the ellipse model for seismic hazard analysis, and give a computation example.展开更多
压电快反镜(Piezoelectric Fast Steering Mirror,PFSM)固有的迟滞特性严重制约了其在精密定位系统中的控制精度。为此,从时间复杂度、求逆必要条件及误差来源3个核心维度,系统对比了常见包络函数的性能差异,综合性选取了非对称线性包...压电快反镜(Piezoelectric Fast Steering Mirror,PFSM)固有的迟滞特性严重制约了其在精密定位系统中的控制精度。为此,从时间复杂度、求逆必要条件及误差来源3个核心维度,系统对比了常见包络函数的性能差异,综合性选取了非对称线性包络函数,采用了基于非对称线性包络函数的率相关广义Prandtl-Ishlinskii模型(Rate-Dependent General⁃ized Prandtl-Ishlinskii Model with Asymmetric Linear Envelope Function,LRGPI)。为解决迟滞的率相关问题,引入导数项拓宽了模型的适用频率范围。随后,构建LRGPI逆模型前馈,对比验证迟滞补偿的有效性。最后,设计基于逆模型前馈的复合控制方法,抑制外界干扰的影响。仿真实验表明,LRGPI逆模型前馈控制相较于基于tanh包络函数的率相关广义PI(Tanh Envelope-Based Rate-Dependent Generalized Prandtl-Ishlinskii Model,TRGPI)逆模型和基于三次项包络函数的率相关广义PI(Cubic Envelope-Based Rate-Dependent Generalized Prandtl-Ishlinskii Model,CRGPI)逆模型,迟滞补偿的带宽分别提高了5.78%和28.69%。基于逆模型前馈补偿的对比实验进一步表明,LRGPI逆模型前馈控制的RMSE相比PI逆模型、TRGPI和CRGPI逆模型分别减少了62.7%,23.2%和26.4%,充分证明LRGPI模型在解决PF⁃SM的迟滞行为方面具有显著的优越性和稳定性。展开更多
Motivated by the autopilot of an unmanned aerial vehicle（UAV） with a wide flight envelope span experiencing large parametric variations in the presence of uncertainties, a fuzzy adaptive tracking controller（FATC） ...Motivated by the autopilot of an unmanned aerial vehicle（UAV） with a wide flight envelope span experiencing large parametric variations in the presence of uncertainties, a fuzzy adaptive tracking controller（FATC） is proposed. The controller consists of a fuzzy baseline controller and an adaptive increment, and the main highlight is that the fuzzy baseline controller and adaptation laws are both based on the fuzzy multiple Lyapunov function approach, which helps to reduce the conservatism for the large envelope and guarantees satisfactory tracking performances with strong robustness simultaneously within the whole envelope. The constraint condition of the fuzzy baseline controller is provided in the form of linear matrix inequality（LMI）, and it specifies the satisfactory tracking performances in the absence of uncertainties. The adaptive increment ensures the uniformly ultimately bounded（UUB） predication errors to recover satisfactory responses in the presence of uncertainties. Simulation results show that the proposed controller helps to achieve high-accuracy tracking of airspeed and altitude desirable commands with strong robustness to uncertainties throughout the entire flight envelope.展开更多
Objective To evaluate the environmental and technical efficiencies of China＇s industrial sectors and provide appropriate advice for policy makers in the context of rapid economic growth and concurrent serious environ...Objective To evaluate the environmental and technical efficiencies of China＇s industrial sectors and provide appropriate advice for policy makers in the context of rapid economic growth and concurrent serious environmental damages caused by industrial pollutants. Methods A data of envelopment analysis （DEA） framework crediting both reduction of pollution outputs and expansion of good outputs was designed as a model to compute environmental efficiency of China＇s regional industrial systems. Results As shown by the geometric mean of environmental efficiency, if other inputs were made constant and good outputs were not to be improved, the air pollution outputs would have the potential to be decreased by about 60% in the whole China. Conclusion Both environmental and technical efficiencies have the potential to be greatly improved in China, which may provide some advice for policy-makers.展开更多
Full waveform inversion is a fitting process based on full seismic wave field simulation data using the full waveform information in seismic records and theoretically it is the ultimate goal of seismic inversion. Howe...Full waveform inversion is a fitting process based on full seismic wave field simulation data using the full waveform information in seismic records and theoretically it is the ultimate goal of seismic inversion. However,there are many problems to be solved in practical application. Firstly,it is the strong nonlinear problem between the seismic wave field and inversion parameters; secondly,the lack of low-frequency information in seismic records. In this study,the envelope is used as objective function inversion to provide the inversion result for the multi-scale full waveform inversion as the initial model,solving the lack of low-frequency information in seismic records. Taking the envelope of seismic records as the objective function in combination of multi-scale full waveform inversion became a new inversion strategy,which naturally achieved the compensation of shortage of low-frequency information and inversion from low frequency to high frequency,reducing the non-linearity in the inversion process. The comparison of the result of full waveform inversion of the initial model built through envelope inversion with the result of the conventional multi-scale full waveform inversion indicates the effectiveness of envelope inversion for the recovery of low-frequency information in seismic records.展开更多
局部均值分解(Local mean decomposition,简称LMD)方法通过滑动平均方法平滑局部均值线段和局部幅值线段得到局部均值函数和包络估计函数,从而实现信号的分解。但滑动平均方法会产生相位差以及平滑步长的选择具有一定的主观性,这样会使...局部均值分解(Local mean decomposition,简称LMD)方法通过滑动平均方法平滑局部均值线段和局部幅值线段得到局部均值函数和包络估计函数,从而实现信号的分解。但滑动平均方法会产生相位差以及平滑步长的选择具有一定的主观性,这样会使分解结果不理想。对LMD方法进行了改进,采用有理样条插值函数(Rationalspline)求取信号的上下包络线,然后通过上下包络线计算信号的局部均值函数和包络估计函数,克服了原LMD方法中采用滑动平均方法带来的缺陷。通过对仿真信号以及滚动轴承故障振动信号的分析,表明改进后的LMD方法优于原LMD方法。展开更多
基金the National Nature Science Foundation of China(No.81170507)the Shanghai International Science and Technology Cooperation Foundation Project(No.11140903700)
文摘In order to explore the cell composition and its metabolism,it is important to let computer recognize the cells and get the counts of different cells for a sample.This paper proposes an L-shaped envelop function and the related fuzzy clustering method as a way to identify the megakaryocyte and the red cell from the sliced marrow image.This method is useful when the staining is insufficient and the color cannot be used as the identifying factor.This method uses the experimental histogram data to fit the L-shaped function and then use it as the envelop for the match test.The fuzzy c-means(FCM) performance index is used to test the adjacent area and get the minimum and finally secure the identification.The new method is not limited to megakaryocyte or red cell and can be used for general purposes of cell recognition.Tests show that this envelop function can ensure the recognition rate with different staining batches and can reach satisfied counting under similar illumination condition.
文摘After the time history of seismic motion is represented by superposition of a series of narrow frequency band wave groups, we obtain a general relation between wave group arrival time and derivative of phase spectra in the paper. On the basis of the relation, frequency number distribution function of wave group arrival time is completely equivalent to that of phase difference spectra. Under the assumption that phase angles of seismic motionobey uniform distribution ranged from 0 to ─ 2π, a quantitative relation between intensity envelope function of seismic motion and energy distribution function with wave group arrival time has been derived in this paper. The relation illuminates inner links among Fourier amplitude spectra and derivative of phase spectra and intensity envelope function. Some examples given by the paper support the conclusions mentioned above.
基金sponsored under the keyresearch project of social development of Zhejiang Province(2005C23075)
文摘It has been a period of time since the concept of scenario earthquake was proposed, but this concept has rarely been used in seismic safety evaluation in China since then. Meanwhile, because of the uncertainties of magnitudes-distances pairs, there is large arbitrariness while determining the envelope function of time histories in seismic hazard analysis. In this paper, we describe a method to control the envelope functions of the time histories by introducing the most-likely combinations of magnitude and distance of the scenario earthquakes based on a probabilistic method, revise the software of the ellipse model for seismic hazard analysis, and give a computation example.
文摘Motivated by the autopilot of an unmanned aerial vehicle（UAV） with a wide flight envelope span experiencing large parametric variations in the presence of uncertainties, a fuzzy adaptive tracking controller（FATC） is proposed. The controller consists of a fuzzy baseline controller and an adaptive increment, and the main highlight is that the fuzzy baseline controller and adaptation laws are both based on the fuzzy multiple Lyapunov function approach, which helps to reduce the conservatism for the large envelope and guarantees satisfactory tracking performances with strong robustness simultaneously within the whole envelope. The constraint condition of the fuzzy baseline controller is provided in the form of linear matrix inequality（LMI）, and it specifies the satisfactory tracking performances in the absence of uncertainties. The adaptive increment ensures the uniformly ultimately bounded（UUB） predication errors to recover satisfactory responses in the presence of uncertainties. Simulation results show that the proposed controller helps to achieve high-accuracy tracking of airspeed and altitude desirable commands with strong robustness to uncertainties throughout the entire flight envelope.
文摘Objective To evaluate the environmental and technical efficiencies of China＇s industrial sectors and provide appropriate advice for policy makers in the context of rapid economic growth and concurrent serious environmental damages caused by industrial pollutants. Methods A data of envelopment analysis （DEA） framework crediting both reduction of pollution outputs and expansion of good outputs was designed as a model to compute environmental efficiency of China＇s regional industrial systems. Results As shown by the geometric mean of environmental efficiency, if other inputs were made constant and good outputs were not to be improved, the air pollution outputs would have the potential to be decreased by about 60% in the whole China. Conclusion Both environmental and technical efficiencies have the potential to be greatly improved in China, which may provide some advice for policy-makers.
基金Supported by Project of National Natural Science Foundation of China(No.41274120)
文摘Full waveform inversion is a fitting process based on full seismic wave field simulation data using the full waveform information in seismic records and theoretically it is the ultimate goal of seismic inversion. However,there are many problems to be solved in practical application. Firstly,it is the strong nonlinear problem between the seismic wave field and inversion parameters; secondly,the lack of low-frequency information in seismic records. In this study,the envelope is used as objective function inversion to provide the inversion result for the multi-scale full waveform inversion as the initial model,solving the lack of low-frequency information in seismic records. Taking the envelope of seismic records as the objective function in combination of multi-scale full waveform inversion became a new inversion strategy,which naturally achieved the compensation of shortage of low-frequency information and inversion from low frequency to high frequency,reducing the non-linearity in the inversion process. The comparison of the result of full waveform inversion of the initial model built through envelope inversion with the result of the conventional multi-scale full waveform inversion indicates the effectiveness of envelope inversion for the recovery of low-frequency information in seismic records.
文摘局部均值分解(Local mean decomposition,简称LMD)方法通过滑动平均方法平滑局部均值线段和局部幅值线段得到局部均值函数和包络估计函数,从而实现信号的分解。但滑动平均方法会产生相位差以及平滑步长的选择具有一定的主观性,这样会使分解结果不理想。对LMD方法进行了改进,采用有理样条插值函数(Rationalspline)求取信号的上下包络线,然后通过上下包络线计算信号的局部均值函数和包络估计函数,克服了原LMD方法中采用滑动平均方法带来的缺陷。通过对仿真信号以及滚动轴承故障振动信号的分析,表明改进后的LMD方法优于原LMD方法。
