针对传统重采样算法易引起粒子贫化的问题,提出了自适应不完全重采样粒子滤波(A particle filter based on adaptive part resampling,APRPF)算法.APRPF以分步的方式仅对部分粒子进行重采样,以递推的方式计算表征粒子退化程度的度量函数...针对传统重采样算法易引起粒子贫化的问题,提出了自适应不完全重采样粒子滤波(A particle filter based on adaptive part resampling,APRPF)算法.APRPF以分步的方式仅对部分粒子进行重采样,以递推的方式计算表征粒子退化程度的度量函数(Measurement of particle degeneracy,MPD),直到满足给定条件.重采样后的粒子由新生粒子和未参与重采样的粒子组成,前者的存在有助于缓解退化问题,后者可使粒子集保持一定多样性.实验结果表明,与标准粒子滤波(Sampling importance resampling,SIR)、辅助变量粒子滤波(Auxiliary particle filter,APF)、正则化粒子滤波(Regularized particle filter,RPF)三种滤波器相比,APRPF的估计精度高;由于平均重采样次数少,计算量也小.展开更多
Five years＇ （2000-2004） continuous study has been carried out on small mammals such as rodents in seven different sample plots, at three different altitudes and in six different ecological environment types in the ...Five years＇ （2000-2004） continuous study has been carried out on small mammals such as rodents in seven different sample plots, at three different altitudes and in six different ecological environment types in the eastern part of the Wuling Mountains, south bank of the Three Gorges of Yangtze River in Hubei. A total of 29 297 rat clamps/times were placed and 2271 small mammals such as rodents were captured, and 26 small mammals were captured by other means. All the small mammals captured belonged to 8 families 19 genera and 24 species, of which rodentia accounted for 70.83% and insectivora 29.17%. Through analysis of the data, the results showed that： 1 ） although the species richness had a trend of increasing along different sample plots as altitude increased from south to north, quite a few species showed a wide habitat range in a vertical distribution （ 15 species were dispersed over three zones and two species over two zones） , indicating a strong adaptability of small mammals such as rOdents at lower altitudes in most areas and comparatively less vertical span of entire mountains; 2） whether in seven different sample plots or six different ecological types, Apodemus agrarius and Rattus norvegicus were dominant species below 1200m, and Anourosorex squamipes, Niviventer confucianus and Apodemus draco were dominant above altitudes of 1300m, however, in quantity they were short of identical regularity, meaning they did not increase as the altitude did, or decrease as the ecological areas changed; 3）the density in winter was obviously greater than that in spring, and the distribution showed an increasing trend along with altitude, but the density in different sample plots was short of identical regularity, showing changes in different seasons and altitude grades had an important impact on small mammals such as rodents; 4） in species diversity and evenness index, there were obvious changes between the seven different sample plots, probably caused by frequent human interference in this area. Com展开更多
1 Scope This standard specifies the definition and test methods of flowability of dense and insulating refractory castables, and moulding equipment, moulding methods, curing and drying conditions of castables samples.
文摘针对传统重采样算法易引起粒子贫化的问题,提出了自适应不完全重采样粒子滤波(A particle filter based on adaptive part resampling,APRPF)算法.APRPF以分步的方式仅对部分粒子进行重采样,以递推的方式计算表征粒子退化程度的度量函数(Measurement of particle degeneracy,MPD),直到满足给定条件.重采样后的粒子由新生粒子和未参与重采样的粒子组成,前者的存在有助于缓解退化问题,后者可使粒子集保持一定多样性.实验结果表明,与标准粒子滤波(Sampling importance resampling,SIR)、辅助变量粒子滤波(Auxiliary particle filter,APF)、正则化粒子滤波(Regularized particle filter,RPF)三种滤波器相比,APRPF的估计精度高;由于平均重采样次数少,计算量也小.
基金National Natural Science Foundation of China(30070679)the Natural Science Foundation of Hubei Province(2004ABA138)+1 种基金the Key Technology R&D Programme Foundation of Hubei Province(2002AA301C43)the Hubei Health Bureau Research Programme Foundation(NX200427)
文摘Five years＇ （2000-2004） continuous study has been carried out on small mammals such as rodents in seven different sample plots, at three different altitudes and in six different ecological environment types in the eastern part of the Wuling Mountains, south bank of the Three Gorges of Yangtze River in Hubei. A total of 29 297 rat clamps/times were placed and 2271 small mammals such as rodents were captured, and 26 small mammals were captured by other means. All the small mammals captured belonged to 8 families 19 genera and 24 species, of which rodentia accounted for 70.83% and insectivora 29.17%. Through analysis of the data, the results showed that： 1 ） although the species richness had a trend of increasing along different sample plots as altitude increased from south to north, quite a few species showed a wide habitat range in a vertical distribution （ 15 species were dispersed over three zones and two species over two zones） , indicating a strong adaptability of small mammals such as rOdents at lower altitudes in most areas and comparatively less vertical span of entire mountains; 2） whether in seven different sample plots or six different ecological types, Apodemus agrarius and Rattus norvegicus were dominant species below 1200m, and Anourosorex squamipes, Niviventer confucianus and Apodemus draco were dominant above altitudes of 1300m, however, in quantity they were short of identical regularity, meaning they did not increase as the altitude did, or decrease as the ecological areas changed; 3）the density in winter was obviously greater than that in spring, and the distribution showed an increasing trend along with altitude, but the density in different sample plots was short of identical regularity, showing changes in different seasons and altitude grades had an important impact on small mammals such as rodents; 4） in species diversity and evenness index, there were obvious changes between the seven different sample plots, probably caused by frequent human interference in this area. Com
文摘1 Scope This standard specifies the definition and test methods of flowability of dense and insulating refractory castables, and moulding equipment, moulding methods, curing and drying conditions of castables samples.
