To improve the disassembly efficiency of a U-shaped disassembly line and reduce the potentially harmful effects on the environment and human health,we study the multi-product U-shaped disassembly line balancing proble...To improve the disassembly efficiency of a U-shaped disassembly line and reduce the potentially harmful effects on the environment and human health,we study the multi-product U-shaped disassembly line balancing problem with a fixed number of stations(MUDLBPF).Firstly,we formulate a mathematical model aimed at minimizing cycle time,balancing loads,and reducing hazard indicators.Secondly,a multi-objective variable neighborhood search(MOVNS)algorithm is proposed.A multi-segment encoding method is proposed to maintain the independence of different products.Considering the characteristics of multiple products,a two-stage decoding method is presented.The method includes product assignment and task assignment.To optimize decoding efficiency,a minimum deviation method is put forward to generate feasible solutions.A segmented neighborhood structure containing seven operators is developed to improve the search efficiency.Finally,numerical experiments are performed and the results show that the MOVNS can solve the MUDLBPF effectively and efficiently.展开更多
This paper presents a Doppler passive location method for moving targets with fixed single station using the Doppler frequency shift and time difference information.First,based on the relationship between frequency sh...This paper presents a Doppler passive location method for moving targets with fixed single station using the Doppler frequency shift and time difference information.First,based on the relationship between frequency shift and path difference,the virtual path difference is calculated from the measured value of Doppler frequency shift by means of mean value correction.Then,under the assumption that the target is moving at a constant speed along a straight line,two coaxial virtual double base arrays are constructed by using the moving track of the moving target based on the method of fixed period time difference.On this basis,the moving distance of the moving target can be calculated by using the ratio relationship between the frequency difference and the radial distance between the two adjacent detection points in the middle of the array,and the linear solution of the two double base path difference positioning equations.At this point,the relative coordinate position of the moving target can be obtained by directly using the linear solution of the double base path difference positioning equation again.展开更多
基金supported by the National Natural Science Foundation of China(No.52175449).
文摘To improve the disassembly efficiency of a U-shaped disassembly line and reduce the potentially harmful effects on the environment and human health,we study the multi-product U-shaped disassembly line balancing problem with a fixed number of stations(MUDLBPF).Firstly,we formulate a mathematical model aimed at minimizing cycle time,balancing loads,and reducing hazard indicators.Secondly,a multi-objective variable neighborhood search(MOVNS)algorithm is proposed.A multi-segment encoding method is proposed to maintain the independence of different products.Considering the characteristics of multiple products,a two-stage decoding method is presented.The method includes product assignment and task assignment.To optimize decoding efficiency,a minimum deviation method is put forward to generate feasible solutions.A segmented neighborhood structure containing seven operators is developed to improve the search efficiency.Finally,numerical experiments are performed and the results show that the MOVNS can solve the MUDLBPF effectively and efficiently.
文摘This paper presents a Doppler passive location method for moving targets with fixed single station using the Doppler frequency shift and time difference information.First,based on the relationship between frequency shift and path difference,the virtual path difference is calculated from the measured value of Doppler frequency shift by means of mean value correction.Then,under the assumption that the target is moving at a constant speed along a straight line,two coaxial virtual double base arrays are constructed by using the moving track of the moving target based on the method of fixed period time difference.On this basis,the moving distance of the moving target can be calculated by using the ratio relationship between the frequency difference and the radial distance between the two adjacent detection points in the middle of the array,and the linear solution of the two double base path difference positioning equations.At this point,the relative coordinate position of the moving target can be obtained by directly using the linear solution of the double base path difference positioning equation again.
