针对标准黏菌算法(Slime Mould Algorithm,SMA)收敛速度较慢、初始种群多样性低以及全局寻优较差等问题,提出一种基于混沌映射和莱维飞行的黏菌优化算法(Chaotic Map and Levy Flight based Slime Mould Optimization Algorithm,CLSMA)...针对标准黏菌算法(Slime Mould Algorithm,SMA)收敛速度较慢、初始种群多样性低以及全局寻优较差等问题,提出一种基于混沌映射和莱维飞行的黏菌优化算法(Chaotic Map and Levy Flight based Slime Mould Optimization Algorithm,CLSMA)。首先,利用circle混沌映射产生的混沌序列初始化黏菌种群,丰富黏菌种群多样性;其次,引入莱维飞行策略,改进黏菌在接近食物阶段的位置更新方式,扩大黏菌的搜索空间,增强算法全局搜索能力;最后,利用局部随机游走策略,提高算法在局部开发的能力,同时利用贪婪原则,选择是否更新黏菌的最优位置。为了验证改进算法的性能,选取12个基准测试函数将CLSMA与五种不同算法进行对比。实验结果表明,所提算法具有较好的收敛性,稳定性以及全局搜索的能力。展开更多
The unreasonable nitrogen(N)supply and low productivity are the main factors restricting the sustainable development of processing tomatoes.In addition,the mechanism by which the N application strategy affects root gr...The unreasonable nitrogen(N)supply and low productivity are the main factors restricting the sustainable development of processing tomatoes.In addition,the mechanism by which the N application strategy affects root growth and nitrate distributions in processing tomatoes remains unclear.In this study,we applied four N application levels to a field(including 0(N0),200(N200),300(N300),and 400(N400)kg/hm^(2))based on the critical N absorption ratio at each growth stage(planting stage to flowering stage:22%;fruit setting stage:24%;red ripening stage:45%;and maturity stage:9%).The results indicated that N300 treatment significantly improved the aboveground dry matter(DM),yield,N uptake,and nitrogen use efficiency(NUE),while N400 treatment increased nitrate nitrogen(NO_(3)^(-)-N)residue in the 20–60 cm soil layer.Temporal variations of total root dry weight(TRDW)and total root length(TRL)showed a single-peak curve.Overall,N300 treatment improved the secondary root parameter of TRDW,while N400 treatment improved the secondary root parameter of TRL.The grey correlation coefficients indicated that root dry weight density(RDWD)in the surface soil(0–20 cm)had the strongest relationship with yield,whereas root length density(RLD)in the middle soil(20–40 cm)had a strong relationship with yield.The path model indicated that N uptake is a crucial factor affecting aboveground DM,TRDW,and yield.The above results indicate that N application levels based on critical N absorption improve the production of processing tomatoes by regulating N uptake and root distribution.Furthermore,the results of this study provide a theoretical basis for precise N management.展开更多
文摘针对标准黏菌算法(Slime Mould Algorithm,SMA)收敛速度较慢、初始种群多样性低以及全局寻优较差等问题,提出一种基于混沌映射和莱维飞行的黏菌优化算法(Chaotic Map and Levy Flight based Slime Mould Optimization Algorithm,CLSMA)。首先,利用circle混沌映射产生的混沌序列初始化黏菌种群,丰富黏菌种群多样性;其次,引入莱维飞行策略,改进黏菌在接近食物阶段的位置更新方式,扩大黏菌的搜索空间,增强算法全局搜索能力;最后,利用局部随机游走策略,提高算法在局部开发的能力,同时利用贪婪原则,选择是否更新黏菌的最优位置。为了验证改进算法的性能,选取12个基准测试函数将CLSMA与五种不同算法进行对比。实验结果表明,所提算法具有较好的收敛性,稳定性以及全局搜索的能力。
基金supported by the National Natural Science Foundation of China (42077011).
文摘The unreasonable nitrogen(N)supply and low productivity are the main factors restricting the sustainable development of processing tomatoes.In addition,the mechanism by which the N application strategy affects root growth and nitrate distributions in processing tomatoes remains unclear.In this study,we applied four N application levels to a field(including 0(N0),200(N200),300(N300),and 400(N400)kg/hm^(2))based on the critical N absorption ratio at each growth stage(planting stage to flowering stage:22%;fruit setting stage:24%;red ripening stage:45%;and maturity stage:9%).The results indicated that N300 treatment significantly improved the aboveground dry matter(DM),yield,N uptake,and nitrogen use efficiency(NUE),while N400 treatment increased nitrate nitrogen(NO_(3)^(-)-N)residue in the 20–60 cm soil layer.Temporal variations of total root dry weight(TRDW)and total root length(TRL)showed a single-peak curve.Overall,N300 treatment improved the secondary root parameter of TRDW,while N400 treatment improved the secondary root parameter of TRL.The grey correlation coefficients indicated that root dry weight density(RDWD)in the surface soil(0–20 cm)had the strongest relationship with yield,whereas root length density(RLD)in the middle soil(20–40 cm)had a strong relationship with yield.The path model indicated that N uptake is a crucial factor affecting aboveground DM,TRDW,and yield.The above results indicate that N application levels based on critical N absorption improve the production of processing tomatoes by regulating N uptake and root distribution.Furthermore,the results of this study provide a theoretical basis for precise N management.
