车辆路径与调度问题(Vehicle routing and scheduling problem,VRSP)是制造系统自动化和商业服务系统优化调度要解决的重要问题,常常以路径最短或成本(时间)最小为优化目标.在强制性碳排放政策的影响下,如何通过路径优化与调度实现系统...车辆路径与调度问题(Vehicle routing and scheduling problem,VRSP)是制造系统自动化和商业服务系统优化调度要解决的重要问题,常常以路径最短或成本(时间)最小为优化目标.在强制性碳排放政策的影响下,如何通过路径优化与调度实现系统的节能减排,已经成为管理者一个优化控制的目标.本文建立了针对接送机场服务中以最小碳排放量为目标的车次分配与调度问题的0-1混合整数规划模型,采用了改进的基于时间和地域划分的极线扫描算法.重点通过不同类型、规模测试实例,分别从测试实例的顾客点位置分布、顾客规模以及车辆容量大小、满意度水平分析了对人均碳排放的影响程度,对现实接送机场服务运作中车辆配置和设置服务水平提供了有价值的建议.展开更多
A class of one-way isothermal mass transfer processes with Fick’s diffusive mass transfer law[g ∝Δ(c)]is investigated in this paper.Based on the definition of the mass entransy,the entransy dissipation function whi...A class of one-way isothermal mass transfer processes with Fick’s diffusive mass transfer law[g ∝Δ(c)]is investigated in this paper.Based on the definition of the mass entransy,the entransy dissipation function which reflects the irreversibility of mass transfer ability loss is derived.The optimal concentration allocations of the key components corresponding to the highand low-concentration sides for the minimum entransy dissipation of the mass transfer process are obtained by applying opti- mal control theory and compared with the strategies of the minimum entropy generation,constant mass transfer flux(constant concentration difference),and constant concentration ratio(constant chemical potential difference).The results are as follows. For the optimal mass transfer strategy of the minimum entransy dissipation,the product of the square of the key component concentration difference between the high-and the low-concentration sides and the inert component concentration at the low-concentration side is a constant,while for that of the minimum entropy generation,the ratio of the square of the key com-ponent concentration difference between the high-and the low-concentration sides to the key component concentration at the low-concentration side is a constant;when the mass transfer process is not involved in energy conversion process,the optimi-zation principle should be the minimum entransy dissipation;the mass transfer strategy of constant concentration difference is superior to that of constant concentration ratio.The results obtained in this paper can provide some theoretical guidelines for optimal designs and operations of practical mass transfer processes.展开更多
This paper proposes a new three-dimensional optimal guidance law for impact time control with seeker’s Field-of-View(FOV) constraint to intercept a stationary target. The proposed guidance law is devised in conjuncti...This paper proposes a new three-dimensional optimal guidance law for impact time control with seeker’s Field-of-View(FOV) constraint to intercept a stationary target. The proposed guidance law is devised in conjunction with the concept of biased Proportional Navigation Guidance(PNG). The guidance law developed leverages a nonlinear function to ensure the boundedness of velocity lead angle to cater to the seeker’s FOV limit. It is proven that the impact time error is nullified in a finite-time under the proposed method. Additionally, the optimality of the biased command is theoretically analyzed. Numerical simulations confirm the superiority of the proposed method and validate the analytic findings.展开更多
文摘车辆路径与调度问题(Vehicle routing and scheduling problem,VRSP)是制造系统自动化和商业服务系统优化调度要解决的重要问题,常常以路径最短或成本(时间)最小为优化目标.在强制性碳排放政策的影响下,如何通过路径优化与调度实现系统的节能减排,已经成为管理者一个优化控制的目标.本文建立了针对接送机场服务中以最小碳排放量为目标的车次分配与调度问题的0-1混合整数规划模型,采用了改进的基于时间和地域划分的极线扫描算法.重点通过不同类型、规模测试实例,分别从测试实例的顾客点位置分布、顾客规模以及车辆容量大小、满意度水平分析了对人均碳排放的影响程度,对现实接送机场服务运作中车辆配置和设置服务水平提供了有价值的建议.
基金supported by the National Natural Science Foundation of China(Grant No.10905093)the Program for New Century Excellent Talents in University of China(Grant No.NCET-04-1006)the Foun-dation for the Author of National Excellent Doctoral Dissertation of China(Grant No.200136)
文摘A class of one-way isothermal mass transfer processes with Fick’s diffusive mass transfer law[g ∝Δ(c)]is investigated in this paper.Based on the definition of the mass entransy,the entransy dissipation function which reflects the irreversibility of mass transfer ability loss is derived.The optimal concentration allocations of the key components corresponding to the highand low-concentration sides for the minimum entransy dissipation of the mass transfer process are obtained by applying opti- mal control theory and compared with the strategies of the minimum entropy generation,constant mass transfer flux(constant concentration difference),and constant concentration ratio(constant chemical potential difference).The results are as follows. For the optimal mass transfer strategy of the minimum entransy dissipation,the product of the square of the key component concentration difference between the high-and the low-concentration sides and the inert component concentration at the low-concentration side is a constant,while for that of the minimum entropy generation,the ratio of the square of the key com-ponent concentration difference between the high-and the low-concentration sides to the key component concentration at the low-concentration side is a constant;when the mass transfer process is not involved in energy conversion process,the optimi-zation principle should be the minimum entransy dissipation;the mass transfer strategy of constant concentration difference is superior to that of constant concentration ratio.The results obtained in this paper can provide some theoretical guidelines for optimal designs and operations of practical mass transfer processes.
文摘This paper proposes a new three-dimensional optimal guidance law for impact time control with seeker’s Field-of-View(FOV) constraint to intercept a stationary target. The proposed guidance law is devised in conjunction with the concept of biased Proportional Navigation Guidance(PNG). The guidance law developed leverages a nonlinear function to ensure the boundedness of velocity lead angle to cater to the seeker’s FOV limit. It is proven that the impact time error is nullified in a finite-time under the proposed method. Additionally, the optimality of the biased command is theoretically analyzed. Numerical simulations confirm the superiority of the proposed method and validate the analytic findings.
