A valid image-processing algorithm of weld pool surface reconstruction according to an input image of weld pool based on shape from shading （SFS） in computer vision is presented. The weld pool surface information is...A valid image-processing algorithm of weld pool surface reconstruction according to an input image of weld pool based on shape from shading （SFS） in computer vision is presented. The weld pool surface information is related to the backside weld width, which is crucial to the quality of weld joint. The image of weld pool is recorded with an optical sensing method. Firstly, the reflectance map model, which specifies the imaging process, is estimated. Then, the algorithm of weld pool surface reconstruction based on SFS is implemented by iteration scheme and speeded by hierarchical structure. The results indicate the accuracy and effectiveness of the approach.展开更多
Matching soil grid unit resolutions with polygon unit map scales is important to minimize the uncertainty of regional soil organic carbon(SOC) pool simulation due to their strong influences on the modeling.A series of...Matching soil grid unit resolutions with polygon unit map scales is important to minimize the uncertainty of regional soil organic carbon(SOC) pool simulation due to their strong influences on the modeling.A series of soil grid units at varying cell sizes was derived from soil polygon units at six map scales,namely,1:50 000(C5),1:200 000(D2),1:500 000(P5),1:1 000 000(N1),1:4 000 000(N4) and 1:14 000 000(N14),in the Taihu Region of China.Both soil unit formats were used for regional SOC pool simulation with a De Nitrification-DeC omposition(DNDC) process-based model,which spans the time period from 1982 to 2000 at the six map scales.Four indices,namely,soil type number(STN),area(AREA),average SOC density(ASOCD) and total SOC stocks(SOCS) of surface paddy soils that were simulated by the DNDC,were distinguished from all these soil polygon and grid units.Subjecting to the four index values(IV) from the parent polygon units,the variations in an index value(VIV,%) from the grid units were used to assess its dataset accuracy and redundancy,which reflects the uncertainty in the simulation of SOC pools.Optimal soil grid unit resolutions were generated and suggested for the DNDC simulation of regional SOC pools,matching their respective soil polygon unit map scales.With these optimal raster resolutions,the soil grid units datasets can have the same accuracy as their parent polygon units datasets without any redundancy,when VIV < 1% was assumed to be a criterion for all four indices.A quadratic curve regression model,namely,y = – 0.80 × 10^(–6)x^2 + 0.0228 x + 0.0211(R^2 = 0.9994,P < 0.05),and a power function model R? = 10.394?^(0.2153)(R^2 = 0.9759,P < 0.05) were revealed,which describe the relationship between the optimal soil grid unit resolution(y,km) and soil polygon unit map scale(1:10 000x),the ratio(R?,%) of the optimal soil grid size to average polygon patch size(?,km^2) and the ?,with the highest R^2 among different mathematical regressions,respectively.This knowledge may facilitate the grid partitioning of regions during the investigation and simulation of SOC pool dynamics at a certain map scale,and be referenced to other landscape polygon patches' mesh partition.展开更多
针对饥饿游戏搜索算法(hunger games search, HGS)存在收敛速度慢和易陷入局部最优等缺点,提出了一种基于均衡池和莱维飞行的饥饿游戏搜索算法(equilibrium Lévy hunger games search, ELHGS)。该算法首先利用tent映射产生更具多...针对饥饿游戏搜索算法(hunger games search, HGS)存在收敛速度慢和易陷入局部最优等缺点,提出了一种基于均衡池和莱维飞行的饥饿游戏搜索算法(equilibrium Lévy hunger games search, ELHGS)。该算法首先利用tent映射产生更具多样性的初始种群;受到平衡优化器算法(EO)的启发,提出一种基于动态均衡池收敛的更新公式,其动态调整的更新策略使算法的全局搜索能力增强;为了进一步增强算法跳出局部最优的能力,在一定条件下对种群实施基于莱维飞行的变异操作。对23个基准函数进行仿真实验,结果显示与原始HGS算法相比,ELHGS求解精度更高、收敛更为迅速,在高维度多峰函数问题上效果最为显著。展开更多
基金This project is supported by National Natural Science Foundation of China(No.50575144).
文摘A valid image-processing algorithm of weld pool surface reconstruction according to an input image of weld pool based on shape from shading （SFS） in computer vision is presented. The weld pool surface information is related to the backside weld width, which is crucial to the quality of weld joint. The image of weld pool is recorded with an optical sensing method. Firstly, the reflectance map model, which specifies the imaging process, is estimated. Then, the algorithm of weld pool surface reconstruction based on SFS is implemented by iteration scheme and speeded by hierarchical structure. The results indicate the accuracy and effectiveness of the approach.
基金Under the auspices of Special Project of National Key Research and Development Program(No.2016YFD0200301)National Natural Science Foundation of China(No.41571206)Special Project of National Science and Technology Basic Work(No.2015FY110700-S2)
文摘Matching soil grid unit resolutions with polygon unit map scales is important to minimize the uncertainty of regional soil organic carbon(SOC) pool simulation due to their strong influences on the modeling.A series of soil grid units at varying cell sizes was derived from soil polygon units at six map scales,namely,1:50 000(C5),1:200 000(D2),1:500 000(P5),1:1 000 000(N1),1:4 000 000(N4) and 1:14 000 000(N14),in the Taihu Region of China.Both soil unit formats were used for regional SOC pool simulation with a De Nitrification-DeC omposition(DNDC) process-based model,which spans the time period from 1982 to 2000 at the six map scales.Four indices,namely,soil type number(STN),area(AREA),average SOC density(ASOCD) and total SOC stocks(SOCS) of surface paddy soils that were simulated by the DNDC,were distinguished from all these soil polygon and grid units.Subjecting to the four index values(IV) from the parent polygon units,the variations in an index value(VIV,%) from the grid units were used to assess its dataset accuracy and redundancy,which reflects the uncertainty in the simulation of SOC pools.Optimal soil grid unit resolutions were generated and suggested for the DNDC simulation of regional SOC pools,matching their respective soil polygon unit map scales.With these optimal raster resolutions,the soil grid units datasets can have the same accuracy as their parent polygon units datasets without any redundancy,when VIV < 1% was assumed to be a criterion for all four indices.A quadratic curve regression model,namely,y = – 0.80 × 10^(–6)x^2 + 0.0228 x + 0.0211(R^2 = 0.9994,P < 0.05),and a power function model R? = 10.394?^(0.2153)(R^2 = 0.9759,P < 0.05) were revealed,which describe the relationship between the optimal soil grid unit resolution(y,km) and soil polygon unit map scale(1:10 000x),the ratio(R?,%) of the optimal soil grid size to average polygon patch size(?,km^2) and the ?,with the highest R^2 among different mathematical regressions,respectively.This knowledge may facilitate the grid partitioning of regions during the investigation and simulation of SOC pool dynamics at a certain map scale,and be referenced to other landscape polygon patches' mesh partition.
文摘针对饥饿游戏搜索算法(hunger games search, HGS)存在收敛速度慢和易陷入局部最优等缺点,提出了一种基于均衡池和莱维飞行的饥饿游戏搜索算法(equilibrium Lévy hunger games search, ELHGS)。该算法首先利用tent映射产生更具多样性的初始种群;受到平衡优化器算法(EO)的启发,提出一种基于动态均衡池收敛的更新公式,其动态调整的更新策略使算法的全局搜索能力增强;为了进一步增强算法跳出局部最优的能力,在一定条件下对种群实施基于莱维飞行的变异操作。对23个基准函数进行仿真实验,结果显示与原始HGS算法相比,ELHGS求解精度更高、收敛更为迅速,在高维度多峰函数问题上效果最为显著。
