For absorption linewidth inversion with wavelength modulation spectroscopy（WMS）, an optimized WMS spectral line fitting method was demonstrated to infer absorption linewidth effectively, and the analytical expressio...For absorption linewidth inversion with wavelength modulation spectroscopy（WMS）, an optimized WMS spectral line fitting method was demonstrated to infer absorption linewidth effectively, and the analytical expressions for relationships between Lorentzian linewidth and the separations of first harmonic peak-to-valley and second harmonic zero-crossing were deduced. The transition of CO_2 centered at 4991.25 cm^（-1） was used to verify the optimized spectral fitting method and the analytical expressions. Results showed that the optimized spectra fitting method was able to infer absorption accurately and compute more than 10 times faster than the commonly used numerical fitting procedure. The second harmonic zero-crossing separation method calculated an even 6 orders faster than the spectra fitting without losing any accuracy for Lorentzian dominated cases. Additionally, linewidth calculated through second harmonic zero-crossing was preferred for much smaller error than the first harmonic peak-to-valley separation method. The presented analytical expressions can also be used in on-line optical sensing applications, electron paramagnetic resonance, and further theoretical characterization of absorption lineshape.展开更多
Confidence bands in a Normal Q-Q Plot allow us to detect non-normality of a data set rigorously, and in such a way that the conclusion does not depend on the subjectivity of the observer of the graph. In the construct...Confidence bands in a Normal Q-Q Plot allow us to detect non-normality of a data set rigorously, and in such a way that the conclusion does not depend on the subjectivity of the observer of the graph. In the construction of the graph, it is usual to fit a straight line to the plotted points, which serves both to check the hypothesis of normality (linear configuration of the plotted points) and to produce estimates of the parameters of the distribution. We can opt for dif-ferent types of lines. In this paper, we study the influence of five types of fitted straight lines in a Normal Q-Q Plot used for construction the confidence bands based on the exact distribution of the order statistics.展开更多
Some core techniques related with automatic measurement of two dimensional object are discussed. Two kinds of corner point detecting methods are given. Least square fitting is used for edge line fitting. Region select...Some core techniques related with automatic measurement of two dimensional object are discussed. Two kinds of corner point detecting methods are given. Least square fitting is used for edge line fitting. Region selection for accurate measurement is proposed. Combined with image recognition, location and macro recording file, automatic measurement of two dimensional object is realized.展开更多
In order to improve the accuracy of wireless network positioning,the triangulation method of wireless network positioning technology is proposed,which is based on the linear least square fitting method.It makes the ob...In order to improve the accuracy of wireless network positioning,the triangulation method of wireless network positioning technology is proposed,which is based on the linear least square fitting method.It makes the observed value and the fitting value very close,effectively solves the problem of significant contradiction between the fitting result and the observed value in the principle of least square method,and can realize the accurate measurement of geographic information by wireless network positioning technology.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.61505142)the Tianjin Natural Science Foundation(Grant No.16JCQNJC02100)
文摘For absorption linewidth inversion with wavelength modulation spectroscopy（WMS）, an optimized WMS spectral line fitting method was demonstrated to infer absorption linewidth effectively, and the analytical expressions for relationships between Lorentzian linewidth and the separations of first harmonic peak-to-valley and second harmonic zero-crossing were deduced. The transition of CO_2 centered at 4991.25 cm^（-1） was used to verify the optimized spectral fitting method and the analytical expressions. Results showed that the optimized spectra fitting method was able to infer absorption accurately and compute more than 10 times faster than the commonly used numerical fitting procedure. The second harmonic zero-crossing separation method calculated an even 6 orders faster than the spectra fitting without losing any accuracy for Lorentzian dominated cases. Additionally, linewidth calculated through second harmonic zero-crossing was preferred for much smaller error than the first harmonic peak-to-valley separation method. The presented analytical expressions can also be used in on-line optical sensing applications, electron paramagnetic resonance, and further theoretical characterization of absorption lineshape.
文摘Confidence bands in a Normal Q-Q Plot allow us to detect non-normality of a data set rigorously, and in such a way that the conclusion does not depend on the subjectivity of the observer of the graph. In the construction of the graph, it is usual to fit a straight line to the plotted points, which serves both to check the hypothesis of normality (linear configuration of the plotted points) and to produce estimates of the parameters of the distribution. We can opt for dif-ferent types of lines. In this paper, we study the influence of five types of fitted straight lines in a Normal Q-Q Plot used for construction the confidence bands based on the exact distribution of the order statistics.
文摘Some core techniques related with automatic measurement of two dimensional object are discussed. Two kinds of corner point detecting methods are given. Least square fitting is used for edge line fitting. Region selection for accurate measurement is proposed. Combined with image recognition, location and macro recording file, automatic measurement of two dimensional object is realized.
文摘In order to improve the accuracy of wireless network positioning,the triangulation method of wireless network positioning technology is proposed,which is based on the linear least square fitting method.It makes the observed value and the fitting value very close,effectively solves the problem of significant contradiction between the fitting result and the observed value in the principle of least square method,and can realize the accurate measurement of geographic information by wireless network positioning technology.
