The introduction of 'hydrostatic extraction' scheme, or 'standard stratification approximation', into spectral model gained some advantages compared with commonly used schemes. However, computational i...The introduction of 'hydrostatic extraction' scheme, or 'standard stratification approximation', into spectral model gained some advantages compared with commonly used schemes. However, computational instability may occur for high vertical resolution versions if the stratification parameter C0 taken as a constant. In this paper, the possible cause leading to the instability is discussed and an improved scheme presented where C0 is generalized to be a function of both height and latitudes. Hence the reference atmosphere gets closer to the real atmosphere and the temperature deviation field to be expanded becomes smoother everywhere. Test by real case forecasts shows good computational stability of the new scheme and better prediction performance than-usual schemes of spectral model.展开更多
In this paper we present some of our recent results on applications of spectral techniques over finite fields to the problems of testing and diagnosis of computer systems.
This paper proposes a novel approach for the automatic detection of allergy test (allergy lesion). A hyperspectral microscope system was used to image the test samples which were diagnosed by dermatologist. It was fou...This paper proposes a novel approach for the automatic detection of allergy test (allergy lesion). A hyperspectral microscope system was used to image the test samples which were diagnosed by dermatologist. It was found that allergy of different levels, and healthy skin cells show absorption spectra, which are sufficiently characteristic and yet reproducible enough to allow for differentiation when using a spectroscopic system. Principal components analysis was used to extract relevant features that could be used for classification from these spectra. Preliminary results indicate that the different types of allergy cells can be reliably distinguished by these features. We conclude that hyperspectral microscopic analysis is a promising approach for improving and automating the diagnosis of allergy test as well as another skin lesions.展开更多
To study the role of autonomic nervous system in the period of developing syncope induced by head-up tilt test(HUT), we analysed the changes of heart rate power spectral density(HRPSD) in 50 patients with unexplained ...To study the role of autonomic nervous system in the period of developing syncope induced by head-up tilt test(HUT), we analysed the changes of heart rate power spectral density(HRPSD) in 50 patients with unexplained syncope, including 15 positive patients (Group 1) and 35 negative patients(Group 2), and 15 negative healthy persons(Group 3) in 5 minute periods before and after tilting and 5 minutes before the end of test. HRPSD and their changes in total(T), very low-frequence(VLF), low-frequence(LF), high-frequence(HF) and the ratio of low/high frequence(LF/HF) were similar (P>0.05) 5 minutes before and after tilting among three groups. Five minutes before the end of test, Group 1 had obvious increase of T, VLF, LF and LF/HF while Group 2 and 3 had not such significant changes. There was significant difference(P<0.01) compared Group 1 with Group 2, 3. The results showed that the abnormal regulatory function of autonomic nervous system played an important role in the mechanism of symcope induced by HUT, the positive group had abnormal increase of sympathetic tone and imbalance of sympathetic/parasympathetic neural tone before syncope appeared.展开更多
With the development of numerical weather prediction technology, the traditional global hydrostatic models used in many countries of the world for operational weather forecasting and numerical simulations of general c...With the development of numerical weather prediction technology, the traditional global hydrostatic models used in many countries of the world for operational weather forecasting and numerical simulations of general circulation have become more and more unfit for high-impact weather prediction. To address this, it is important to invest in the development of global nonhydrostatic models. Few existing nonhydrostatic global models use consistently the grid finite difference scheme for the primitive equations of dynamical cores, which can subsequently degrade the accuracy of the calculations. A new nonhydrostatic global spectral model, which utilizes the Eulerian spectral method, is developed here from NCAR Community Atmosphere Model 3.0 （CAM3.0）. Using Janjic＇s hydrostatic/nonhydrostatic method, a global nonhydrostatic spectral method for the primitive equations has been formulated and developed. In order to retain the integrity of the nonhydrostatic equations, the atmospheric curvature correction and eccentricity correction are considered. In this paper, the Held-Suarez idealized test and an idealized baroclinic wave test are first carried out, which shows that the nonhydrostatic global spectral model has similar climate states to the results of many other global models for long-term idealized integration, as well as better simulation ability for short-term idealized integration. Then, a real case experiment is conducted using the new dynamical core with the full physical parameterizations of subgrid-scale physical processes. The 10-day numerical integration indicates a decrease in systematic error and a better simulation of zonal wind, temperature, and 500-hPa height.展开更多
开集分类识别要求分类器不仅能够“辨识”已知类别的测试样本,而且还要有效地“拒识”未知类别的测试样本;在光谱分析中有关的研究与应用相对较少。改进了Ishibuchi提出的经典的闭集框架下的模糊规则多类别分类器,将其应用于开集分类识...开集分类识别要求分类器不仅能够“辨识”已知类别的测试样本,而且还要有效地“拒识”未知类别的测试样本;在光谱分析中有关的研究与应用相对较少。改进了Ishibuchi提出的经典的闭集框架下的模糊规则多类别分类器,将其应用于开集分类识别领域。首先,使用主成分分析法进行原始光谱曲线向量的光谱维度约简,降维至4维~6维的光谱特征向量。其次,将Ishibuchi提出的模糊规则多类别分类器简化为二元分类器版本,采用1-vs-1二元分类器进行分类处理,并且确定该测试样本在相应类别的得票。最后,将所有二元分类器的投票数进行统计,如果某个已知类别的得票数最高,并且该最高得票数大于预先确定的阈值τ,那么测试样本判决为该已知类别;否则就“拒识”为未知类别,从而实现了多类别的开集分类识别。在实验验证中,对于木材和芒果光谱数据集进行了分组的对比实验,结果表明,本方法优于其他的主流的开集分类识别,包括基于广义基本概率分配(generalized Basic probability assignment,GBPA)的改进的开集框架下的模糊规则多类别分类器;具有最好的评价指标F-Score,Kappa系数及总体识别率。此外,还针对芒果光谱数据集的对比实验进行了双尾McNemar s Test统计检验,进一步表明该方法相对于其他的开集分类识别方法来说,具有统计检验意义的优势。展开更多
基金This work has been carried out under the support of the Medium-range Numerical Weather Forecast research project
文摘The introduction of 'hydrostatic extraction' scheme, or 'standard stratification approximation', into spectral model gained some advantages compared with commonly used schemes. However, computational instability may occur for high vertical resolution versions if the stratification parameter C0 taken as a constant. In this paper, the possible cause leading to the instability is discussed and an improved scheme presented where C0 is generalized to be a function of both height and latitudes. Hence the reference atmosphere gets closer to the real atmosphere and the temperature deviation field to be expanded becomes smoother everywhere. Test by real case forecasts shows good computational stability of the new scheme and better prediction performance than-usual schemes of spectral model.
基金This work was supported by the National Science Foundation(USA)under grant MIP 9630096the NATO under Grant 910411Volkswagen Foundation(Germany)
文摘In this paper we present some of our recent results on applications of spectral techniques over finite fields to the problems of testing and diagnosis of computer systems.
文摘This paper proposes a novel approach for the automatic detection of allergy test (allergy lesion). A hyperspectral microscope system was used to image the test samples which were diagnosed by dermatologist. It was found that allergy of different levels, and healthy skin cells show absorption spectra, which are sufficiently characteristic and yet reproducible enough to allow for differentiation when using a spectroscopic system. Principal components analysis was used to extract relevant features that could be used for classification from these spectra. Preliminary results indicate that the different types of allergy cells can be reliably distinguished by these features. We conclude that hyperspectral microscopic analysis is a promising approach for improving and automating the diagnosis of allergy test as well as another skin lesions.
文摘To study the role of autonomic nervous system in the period of developing syncope induced by head-up tilt test(HUT), we analysed the changes of heart rate power spectral density(HRPSD) in 50 patients with unexplained syncope, including 15 positive patients (Group 1) and 35 negative patients(Group 2), and 15 negative healthy persons(Group 3) in 5 minute periods before and after tilting and 5 minutes before the end of test. HRPSD and their changes in total(T), very low-frequence(VLF), low-frequence(LF), high-frequence(HF) and the ratio of low/high frequence(LF/HF) were similar (P>0.05) 5 minutes before and after tilting among three groups. Five minutes before the end of test, Group 1 had obvious increase of T, VLF, LF and LF/HF while Group 2 and 3 had not such significant changes. There was significant difference(P<0.01) compared Group 1 with Group 2, 3. The results showed that the abnormal regulatory function of autonomic nervous system played an important role in the mechanism of symcope induced by HUT, the positive group had abnormal increase of sympathetic tone and imbalance of sympathetic/parasympathetic neural tone before syncope appeared.
基金supported by the China Meteorological Administration Special Fund for numerical prediction(GRAPES)the National Natural Science Foundation of China(Grant Nos.40775067)
文摘With the development of numerical weather prediction technology, the traditional global hydrostatic models used in many countries of the world for operational weather forecasting and numerical simulations of general circulation have become more and more unfit for high-impact weather prediction. To address this, it is important to invest in the development of global nonhydrostatic models. Few existing nonhydrostatic global models use consistently the grid finite difference scheme for the primitive equations of dynamical cores, which can subsequently degrade the accuracy of the calculations. A new nonhydrostatic global spectral model, which utilizes the Eulerian spectral method, is developed here from NCAR Community Atmosphere Model 3.0 （CAM3.0）. Using Janjic＇s hydrostatic/nonhydrostatic method, a global nonhydrostatic spectral method for the primitive equations has been formulated and developed. In order to retain the integrity of the nonhydrostatic equations, the atmospheric curvature correction and eccentricity correction are considered. In this paper, the Held-Suarez idealized test and an idealized baroclinic wave test are first carried out, which shows that the nonhydrostatic global spectral model has similar climate states to the results of many other global models for long-term idealized integration, as well as better simulation ability for short-term idealized integration. Then, a real case experiment is conducted using the new dynamical core with the full physical parameterizations of subgrid-scale physical processes. The 10-day numerical integration indicates a decrease in systematic error and a better simulation of zonal wind, temperature, and 500-hPa height.
文摘开集分类识别要求分类器不仅能够“辨识”已知类别的测试样本,而且还要有效地“拒识”未知类别的测试样本;在光谱分析中有关的研究与应用相对较少。改进了Ishibuchi提出的经典的闭集框架下的模糊规则多类别分类器,将其应用于开集分类识别领域。首先,使用主成分分析法进行原始光谱曲线向量的光谱维度约简,降维至4维~6维的光谱特征向量。其次,将Ishibuchi提出的模糊规则多类别分类器简化为二元分类器版本,采用1-vs-1二元分类器进行分类处理,并且确定该测试样本在相应类别的得票。最后,将所有二元分类器的投票数进行统计,如果某个已知类别的得票数最高,并且该最高得票数大于预先确定的阈值τ,那么测试样本判决为该已知类别;否则就“拒识”为未知类别,从而实现了多类别的开集分类识别。在实验验证中,对于木材和芒果光谱数据集进行了分组的对比实验,结果表明,本方法优于其他的主流的开集分类识别,包括基于广义基本概率分配(generalized Basic probability assignment,GBPA)的改进的开集框架下的模糊规则多类别分类器;具有最好的评价指标F-Score,Kappa系数及总体识别率。此外,还针对芒果光谱数据集的对比实验进行了双尾McNemar s Test统计检验,进一步表明该方法相对于其他的开集分类识别方法来说,具有统计检验意义的优势。
