A wavelength selection method for discrete wavelength combinations was developed based on equi- distant combination-partial least squares （EC-PLS） and applied to a near-infrared （NIR） spectroscopic analysis of hem...A wavelength selection method for discrete wavelength combinations was developed based on equi- distant combination-partial least squares （EC-PLS） and applied to a near-infrared （NIR） spectroscopic analysis of hemoglobin （Hb） in human peripheral blood samples. An allowable model set was established through EC-PLS on the basis of the sequence of the predicted error values. Then, the wavelengths that appeared in the allowable models were sorted, combined, and utilized for modeling, and the optimal number of wavelengths in the combina- tions was determined. The ideal discrete combination models were obtained by traversing the number of allowable models. The obtained optimal EC-PLS and discrete wavelength models contained 71 and 42 wave- lengths, respectively. A simple and high-performance discrete model with 35 wavelengths was also established. The validation samples excluded from modeling were used to validate the three models. The root-mean-square errors for the N1R-predicted and clinically measured Hb values were 3.29, 2.86, and 2.90 g.L ~, respectively; the correlation coefficients, relative RMSER and ratios of performance to deviation were 0.980, 0.983, and 0.981; 2.7%, 2.3%, and 2.4%; and 4.6, 5.3, and 5.2, respectively. The three models achieved high prediction accuracy. Among them, the optimal discrete combination model performed the best and was the most effective in enhancing prediction performance and removing redundant wave- lengths. The proposed optimization method for discrete wavelength combinations is applicable to NIR spectro- scopic analyses of complex samples and can improve prediction performance. The proposed wavelength models can be utilized to design dedicated spectrometers for Hb and can provide a valuable reference for non-invasive Hb detection.展开更多
文摘研究了耦合Level Set(LS)方法处理介质界面算法,通过对比旋转流场和剪切流场下的界面捕捉情况,给出了各种不同方法在处理介质界面过程中的优缺点,分析了产生这种现象的原因。通过对比分析得到,耦合粒子Level Set(Particle Level Set,PLS)方法以及耦合Level Set和VOF(Coupled Level Set and Volume of Fluid,CLSVOF)方法相比于单纯的LS方法,在流体守恒性质方面有很大的提高,PLS方法可以根据撒播粒子和精确追踪示踪粒子修正LS界面;而CLSVOF方法可以通过重构界面和体积输运,重新初始化LS函数。在实际物理应用中,PLS方法多次重新撒播示踪粒子会降低界面精度,且对每个示踪粒子的追踪需要加大CPU内存,而CLSVOF方法更加高效和合理。
文摘A wavelength selection method for discrete wavelength combinations was developed based on equi- distant combination-partial least squares （EC-PLS） and applied to a near-infrared （NIR） spectroscopic analysis of hemoglobin （Hb） in human peripheral blood samples. An allowable model set was established through EC-PLS on the basis of the sequence of the predicted error values. Then, the wavelengths that appeared in the allowable models were sorted, combined, and utilized for modeling, and the optimal number of wavelengths in the combina- tions was determined. The ideal discrete combination models were obtained by traversing the number of allowable models. The obtained optimal EC-PLS and discrete wavelength models contained 71 and 42 wave- lengths, respectively. A simple and high-performance discrete model with 35 wavelengths was also established. The validation samples excluded from modeling were used to validate the three models. The root-mean-square errors for the N1R-predicted and clinically measured Hb values were 3.29, 2.86, and 2.90 g.L ~, respectively; the correlation coefficients, relative RMSER and ratios of performance to deviation were 0.980, 0.983, and 0.981; 2.7%, 2.3%, and 2.4%; and 4.6, 5.3, and 5.2, respectively. The three models achieved high prediction accuracy. Among them, the optimal discrete combination model performed the best and was the most effective in enhancing prediction performance and removing redundant wave- lengths. The proposed optimization method for discrete wavelength combinations is applicable to NIR spectro- scopic analyses of complex samples and can improve prediction performance. The proposed wavelength models can be utilized to design dedicated spectrometers for Hb and can provide a valuable reference for non-invasive Hb detection.
