As the number of electric vehicles(EVs)continues to grow and the demand for charging infrastructure is also increasing,how to improve the charging infrastructure has become a bottleneck restricting the development of ...As the number of electric vehicles(EVs)continues to grow and the demand for charging infrastructure is also increasing,how to improve the charging infrastructure has become a bottleneck restricting the development of EVs.In other words,reasonably planning the location and capacity of charging stations is important for development of the EV industry and the safe and stable operation of the power system.Considering the construction and maintenance of the charging station,the distribution network loss of the charging station,and the economic loss on the user side of the EV,this paper takes the node and capacity of charging station planning as control variables and the minimum cost of system comprehensive planning as objective function,and thus proposes a location and capacity planning model for the EV charging station.Based on the problems of low efficiency and insufficient global optimization ability of the current algorithm,the simulated annealing immune particle swarm optimization algorithm(SA-IPSO)is adopted in this paper.The simulated annealing algorithm is used in the global update of the particle swarm optimization(PSO),and the immune mechanism is introduced to participate in the iterative update of the particles,so as to improve the speed and efficiency of PSO.Voronoi diagram is used to divide service area of the charging station,and a joint solution process of Voronoi diagram and SA-IPSO is proposed.By example analysis,the results show that the optimal solution corresponding to the optimisation method proposed in this paper has a low overall cost,while the average charging waiting time is only 1.8 min and the charging pile utilisation rate is 75.5%.The simulation comparison verifies that the improved algorithm improves the operational efficiency by 18.1%and basically does not fall into local convergence.展开更多
We are constrained by widespread cancerous diseases to improve treatment methods which save patients and provide better living conditions during and after the treatment period.Because of the complexity of the treatmen...We are constrained by widespread cancerous diseases to improve treatment methods which save patients and provide better living conditions during and after the treatment period.Because of the complexity of the treatment process,mathematical models need to be used in order to have a better understanding of the process.However,deriving an adequate complex model that can capture the disease pattern which could be confirmed by simulations and experiments has its own barriers.In this paper,a new mathematical model is developed concerning immune system effect on cancer.The model is introduced using nonlinear ordinary differential equations.Also,the qualitative behavior of the proposed system is studied in order to examine the extent of the model with respect to the nature of tumor evolution.Thus,number and status of equilibria points in line with the existence of limit cycles are obtained for sub-systems and the whole system.Meanwhile,possible bifurcations are mentioned,and the consequent evolutions are described.It is shown that the model conforms well to natural possibilities,cancer growth or remission.Thus,the model would be fit for further studies for prediction and contemplating treatment method,especially for immune stimulating drugs and immunotherapy.展开更多
In this paper, an efficient multi-conductor simplification technique is proposed to model the electromagnetic immunity on cable bundles within a braid shielding structure over a large frequency range. By grouping toge...In this paper, an efficient multi-conductor simplification technique is proposed to model the electromagnetic immunity on cable bundles within a braid shielding structure over a large frequency range. By grouping together the conductors based on the knowledge of Z-Smith chart, the required computation time is markedly reduced and the complexity of modeling the completely shielding cable bundles is significantly simplified with a good accuracy. After a brief description of the immunity problems in shielding structure, a six-phase procedure is detailed to generate the geometrical characteristics of the reduced cable bundles. Numerical simulation is carried out by using a commercial software CST to validate the efficiency and advantages of the proposed approach. The research addressed in this paper is considered as a simplified modeling technique for the electromagnetic immunity within a shielding structure.展开更多
基金Key R&D Program of Tianjin,China(No.20YFYSGX00060).
文摘As the number of electric vehicles(EVs)continues to grow and the demand for charging infrastructure is also increasing,how to improve the charging infrastructure has become a bottleneck restricting the development of EVs.In other words,reasonably planning the location and capacity of charging stations is important for development of the EV industry and the safe and stable operation of the power system.Considering the construction and maintenance of the charging station,the distribution network loss of the charging station,and the economic loss on the user side of the EV,this paper takes the node and capacity of charging station planning as control variables and the minimum cost of system comprehensive planning as objective function,and thus proposes a location and capacity planning model for the EV charging station.Based on the problems of low efficiency and insufficient global optimization ability of the current algorithm,the simulated annealing immune particle swarm optimization algorithm(SA-IPSO)is adopted in this paper.The simulated annealing algorithm is used in the global update of the particle swarm optimization(PSO),and the immune mechanism is introduced to participate in the iterative update of the particles,so as to improve the speed and efficiency of PSO.Voronoi diagram is used to divide service area of the charging station,and a joint solution process of Voronoi diagram and SA-IPSO is proposed.By example analysis,the results show that the optimal solution corresponding to the optimisation method proposed in this paper has a low overall cost,while the average charging waiting time is only 1.8 min and the charging pile utilisation rate is 75.5%.The simulation comparison verifies that the improved algorithm improves the operational efficiency by 18.1%and basically does not fall into local convergence.
文摘We are constrained by widespread cancerous diseases to improve treatment methods which save patients and provide better living conditions during and after the treatment period.Because of the complexity of the treatment process,mathematical models need to be used in order to have a better understanding of the process.However,deriving an adequate complex model that can capture the disease pattern which could be confirmed by simulations and experiments has its own barriers.In this paper,a new mathematical model is developed concerning immune system effect on cancer.The model is introduced using nonlinear ordinary differential equations.Also,the qualitative behavior of the proposed system is studied in order to examine the extent of the model with respect to the nature of tumor evolution.Thus,number and status of equilibria points in line with the existence of limit cycles are obtained for sub-systems and the whole system.Meanwhile,possible bifurcations are mentioned,and the consequent evolutions are described.It is shown that the model conforms well to natural possibilities,cancer growth or remission.Thus,the model would be fit for further studies for prediction and contemplating treatment method,especially for immune stimulating drugs and immunotherapy.
基金Project supported by the National Natural Science Foundation of China(Grant No.51675086)the National Defense Pre-Research Foundation of China(Grant No.6140758010116DZ02002)
文摘In this paper, an efficient multi-conductor simplification technique is proposed to model the electromagnetic immunity on cable bundles within a braid shielding structure over a large frequency range. By grouping together the conductors based on the knowledge of Z-Smith chart, the required computation time is markedly reduced and the complexity of modeling the completely shielding cable bundles is significantly simplified with a good accuracy. After a brief description of the immunity problems in shielding structure, a six-phase procedure is detailed to generate the geometrical characteristics of the reduced cable bundles. Numerical simulation is carried out by using a commercial software CST to validate the efficiency and advantages of the proposed approach. The research addressed in this paper is considered as a simplified modeling technique for the electromagnetic immunity within a shielding structure.