Cropping structure has a close relationship with the optimal allocation of agricultural water resources. Based on the analysis of the relationship between agricultural water resources and sustainable development, this...Cropping structure has a close relationship with the optimal allocation of agricultural water resources. Based on the analysis of the relationship between agricultural water resources and sustainable development, this paper presents a multi objective fuzzy optimization model for cropping structure and water allocation, which overcomes the shortcoming of current models that only considered the economic objective,and ignored the social and environmental objectives. During the process, a new method named fuzzy deciding weight is developed to decide the objective weight. A case study shows that the model is reliable, the method is simple and objective, and the results are reasonable. This model is useful for agricultural management and sustainable development.展开更多
Because of the increasingly prominent problem of alumina content inhomogeneity in large or super-scale aluminum reduction cells,a transient numerical model for the alumina mixing process was developed for a400kA cell,...Because of the increasingly prominent problem of alumina content inhomogeneity in large or super-scale aluminum reduction cells,a transient numerical model for the alumina mixing process was developed for a400kA cell,and the relationship between the alumina content distribution and electrolyte flow field was analyzed.In the ANSYS software platform,several numerical simulation cases were presented to display the influence of the feeder configuration on the alumina mixing characteristics.The results showed that a large vortex flow of the molten electrolyte is beneficial for alumina mixing and uniform distribution in the inner areas of the vortexes.The alumina particles reach the inter-electrode zone in10?15s from the beginning of the feeding action,and the risk of early precipitation occurs in10?25s after the feeding.It was also found that a suitable grouping of feeders could reduce the content fluctuation and gradient.Therefore,a feeding on demand strategy was proposed,and the simulation results showed that although the spatial characteristics are not changed,the uniformity of the alumina content was markedly improved.展开更多
Spectrum access approach and power allocation scheme are important techniques in cognitive radio(CR) system,which not only affect communication performance of CR user(secondary user,SU) but also play decisive role for...Spectrum access approach and power allocation scheme are important techniques in cognitive radio(CR) system,which not only affect communication performance of CR user(secondary user,SU) but also play decisive role for protection of primary user(PU).In this study,we propose a power allocation scheme for SU based on the status sensing of PU in a single-input single-output(SISO) CR network.Instead of the conventional binary primary transmit power strategy,namely the sensed PU has only present or absent status,we consider a more practical scenario when PU transmits with multiple levels of power and quantized side information known by SU in advance as a primary quantized codebook.The secondary power allocation scheme to maximize the average throughput under the rate loss constraint(RLC) of PU is parameterized by the sensing results for PU,the primary quantized codebook and the channel state information(CSI) of SU.Furthermore,Differential Evolution(DE) algorithm is used to solve this non-convex power allocation problem.Simulation results show the performance and effectiveness of our proposed scheme under more practical communication conditions.展开更多
文摘Cropping structure has a close relationship with the optimal allocation of agricultural water resources. Based on the analysis of the relationship between agricultural water resources and sustainable development, this paper presents a multi objective fuzzy optimization model for cropping structure and water allocation, which overcomes the shortcoming of current models that only considered the economic objective,and ignored the social and environmental objectives. During the process, a new method named fuzzy deciding weight is developed to decide the objective weight. A case study shows that the model is reliable, the method is simple and objective, and the results are reasonable. This model is useful for agricultural management and sustainable development.
基金Projects(51574289,61533020,51674300)supported by the National Natural Science Foundation of ChinaProject(2015CXS017)supported by Innovation-driven Plan in Central South University,China
文摘Because of the increasingly prominent problem of alumina content inhomogeneity in large or super-scale aluminum reduction cells,a transient numerical model for the alumina mixing process was developed for a400kA cell,and the relationship between the alumina content distribution and electrolyte flow field was analyzed.In the ANSYS software platform,several numerical simulation cases were presented to display the influence of the feeder configuration on the alumina mixing characteristics.The results showed that a large vortex flow of the molten electrolyte is beneficial for alumina mixing and uniform distribution in the inner areas of the vortexes.The alumina particles reach the inter-electrode zone in10?15s from the beginning of the feeding action,and the risk of early precipitation occurs in10?25s after the feeding.It was also found that a suitable grouping of feeders could reduce the content fluctuation and gradient.Therefore,a feeding on demand strategy was proposed,and the simulation results showed that although the spatial characteristics are not changed,the uniformity of the alumina content was markedly improved.
基金supported by the National Natural Science Foundation of China(Grant No.61571209)
文摘Spectrum access approach and power allocation scheme are important techniques in cognitive radio(CR) system,which not only affect communication performance of CR user(secondary user,SU) but also play decisive role for protection of primary user(PU).In this study,we propose a power allocation scheme for SU based on the status sensing of PU in a single-input single-output(SISO) CR network.Instead of the conventional binary primary transmit power strategy,namely the sensed PU has only present or absent status,we consider a more practical scenario when PU transmits with multiple levels of power and quantized side information known by SU in advance as a primary quantized codebook.The secondary power allocation scheme to maximize the average throughput under the rate loss constraint(RLC) of PU is parameterized by the sensing results for PU,the primary quantized codebook and the channel state information(CSI) of SU.Furthermore,Differential Evolution(DE) algorithm is used to solve this non-convex power allocation problem.Simulation results show the performance and effectiveness of our proposed scheme under more practical communication conditions.
