传统的遗传算法在遗传操作的过程中,不管具体问题对种群规模的要求都事先指定,造成种群规模表现的不合理。针对这一问题,Arabas,J.等人提出了一种变种群规模遗传算法GAVaPS(Genetic Algorithms withVarying Population Size),旨在遗传...传统的遗传算法在遗传操作的过程中,不管具体问题对种群规模的要求都事先指定,造成种群规模表现的不合理。针对这一问题,Arabas,J.等人提出了一种变种群规模遗传算法GAVaPS(Genetic Algorithms withVarying Population Size),旨在遗传操作的过程中自适应地调整种群的规模。黄乐等人提出了一种改进的变种群规模遗传算法VPSG-GM(Varying Population Size Genetic Combined with Gradient Search Method),它与GAVaPS方法在遗传操作上的不同之处是把评价目标函数的步骤置于重组种群时“淘汰”步骤之前,这样做减少了算法由于重组造成的不必要开销。文章提出的改进的变种群规模的遗传算法,在调整种群规模时通过增加补算算子,从而达到保持种群多样性的目的。这样做可以略去变异操作,减少了系统开销。实验证明了该算法的有效性。展开更多
As a typical representative of the herbivorous wild animals in Chang Tang Plateau,the number of Tibetan wild asses has increased significantly in recent years.Clarifying the distribution,population,and size of its hab...As a typical representative of the herbivorous wild animals in Chang Tang Plateau,the number of Tibetan wild asses has increased significantly in recent years.Clarifying the distribution,population,and size of its habitats is conducive to formulating the protection plan for wild animals and managing the conflict between people and wild animals in Chang Tang Plateau.Based on the distribution probability of Tibetan wild ass habitats and environmental factors,the number of Tibetan wild asses in Gaize County of Chang Tang Plateau was calculated by using the belt transect method and random forest model,and due to the uncertainty of the calculations,the results were corrected and analyzed.The results show that the living environment of Tibetan wild asses in Gaize County of Chang Tang Plateau is at 4400-4600 m above sea level,350-400 m away from the river,and the average temperature in the warmest season is 10-12℃.The vegetation types of habitats are generally temperate tufted dwarf grass,dwarf semi shrub desert grassland,alpine grass,Carex grassland,alpine cushion dwarf semi shrub desert,among others.On the basis of studying the environmental preferences of Tibetan wild asses,the random forest model was corrected by using the data of the second scientific survey sample line of Qinghai-Tibet Plateau for three years.The approximate number of Tibetan wild asses in each of the different areas of Gaize County was obtained.The number of Tibetan wild asses in Gaize Town,Xianqian Township,Gumu Township,Chabu Township,Mami Township,Wuma Township and Dongcuo Township is 855,3458,2358,1453,743,943 and 647,respectively.By studying the environmental preferences of Tibetan wild asses and analyzing the results of the belt transect survey,the random forest model can accurately estimate the number of Tibetan wild asses in Gaize County of Chang Tang Plateau.展开更多
文摘传统的遗传算法在遗传操作的过程中,不管具体问题对种群规模的要求都事先指定,造成种群规模表现的不合理。针对这一问题,Arabas,J.等人提出了一种变种群规模遗传算法GAVaPS(Genetic Algorithms withVarying Population Size),旨在遗传操作的过程中自适应地调整种群的规模。黄乐等人提出了一种改进的变种群规模遗传算法VPSG-GM(Varying Population Size Genetic Combined with Gradient Search Method),它与GAVaPS方法在遗传操作上的不同之处是把评价目标函数的步骤置于重组种群时“淘汰”步骤之前,这样做减少了算法由于重组造成的不必要开销。文章提出的改进的变种群规模的遗传算法,在调整种群规模时通过增加补算算子,从而达到保持种群多样性的目的。这样做可以略去变异操作,减少了系统开销。实验证明了该算法的有效性。
基金The Second Tibetan Plateau Scientific Expedition and Research Program,China(2019QZKK0603)The National Natural Science Foundation of China(41971263)The Joint Project between the National Natural Science Foundation of China and the Mongolian Foundation of Science and Technology(32161143025)。
文摘As a typical representative of the herbivorous wild animals in Chang Tang Plateau,the number of Tibetan wild asses has increased significantly in recent years.Clarifying the distribution,population,and size of its habitats is conducive to formulating the protection plan for wild animals and managing the conflict between people and wild animals in Chang Tang Plateau.Based on the distribution probability of Tibetan wild ass habitats and environmental factors,the number of Tibetan wild asses in Gaize County of Chang Tang Plateau was calculated by using the belt transect method and random forest model,and due to the uncertainty of the calculations,the results were corrected and analyzed.The results show that the living environment of Tibetan wild asses in Gaize County of Chang Tang Plateau is at 4400-4600 m above sea level,350-400 m away from the river,and the average temperature in the warmest season is 10-12℃.The vegetation types of habitats are generally temperate tufted dwarf grass,dwarf semi shrub desert grassland,alpine grass,Carex grassland,alpine cushion dwarf semi shrub desert,among others.On the basis of studying the environmental preferences of Tibetan wild asses,the random forest model was corrected by using the data of the second scientific survey sample line of Qinghai-Tibet Plateau for three years.The approximate number of Tibetan wild asses in each of the different areas of Gaize County was obtained.The number of Tibetan wild asses in Gaize Town,Xianqian Township,Gumu Township,Chabu Township,Mami Township,Wuma Township and Dongcuo Township is 855,3458,2358,1453,743,943 and 647,respectively.By studying the environmental preferences of Tibetan wild asses and analyzing the results of the belt transect survey,the random forest model can accurately estimate the number of Tibetan wild asses in Gaize County of Chang Tang Plateau.
