This work considers those road networks in which there are multi-route choices for bifurcation-destination(or origin-destination) pairs, and designs a real-time variable message sign(VMS)-based routing control strateg...This work considers those road networks in which there are multi-route choices for bifurcation-destination(or origin-destination) pairs, and designs a real-time variable message sign(VMS)-based routing control strategy in the model predictive control(MPC) framework. The VMS route recommendation provided by the traffic management authority is directly considered as the control variable, and the routing control model is established, in which a multi-dimensional control vector is introduced to describe the influence of route recommendations on flow distribution. In the MPC framework, a system optimum routing strategy with the constraints regarding drivers' acceptability with recommended routes is designed, which can not only meet the traffic management authority's control requirement but also improve drivers' satisfaction with the route guidance system. The simulation carried out shows that the proposed routing control can effectively mitigate traffic congestion, reduces followers' time delay, and improves drivers' satisfaction with routing control in road networks.展开更多
In an ad hoc network, it is usually difficult to optimize the assignment of network routing resources using a single type of routing protocol due to the differences in network scale, node moving mode and node distribu...In an ad hoc network, it is usually difficult to optimize the assignment of network routing resources using a single type of routing protocol due to the differences in network scale, node moving mode and node distribution. Therefore, it is desirable to have nodes run multiple routing protocols simultaneously so that more than one protocols can be chosen to work jointly. For this purpose, a multiple routing platform for Ad hoc networks is proposed on a higher level of current routing protocols. In order to ensure the security of the platform, a security mechanism and its formal analysis by BAN logic is given. The simulation results of the network performance demonstrate that the proposed multi-routing platform is practicable in some complex applications.展开更多
This paper attempts to optimize optimal capacities, block routing and mine sequencing problems in a mining system. The solution approach is based on a heuristics and the mixed integer programming (MIP). Unlike previou...This paper attempts to optimize optimal capacities, block routing and mine sequencing problems in a mining system. The solution approach is based on a heuristics and the mixed integer programming (MIP). Unlike previous sequential solution approaches, the problems are herein solved at the same time. Furthermore, the proposed approach guarantees practical solutions because it considers ore material distribution within orebody. The paper has two main contributions: (a) the proposed approach generates production rates in a manner that the capacities are satisfied; (b) the proposed approach does not use pre-defined marginal cut-off grades. Thus, idle capacity problem is eliminated and different scheduling combinations are allowed. To see the performance of the approach proposed, a case study is carried out using a gold data. The schedule generated shows that the approach can determine optimal production rates, block destination and sequencing effectively.展开更多
The demand-adaptive system(DAS)has been recognized as a promising transit mode for demand with high fluctuations.In this paper,we optimize the routes and request selection for a DAS with multiple service routes.Curren...The demand-adaptive system(DAS)has been recognized as a promising transit mode for demand with high fluctuations.In this paper,we optimize the routes and request selection for a DAS with multiple service routes.Currently,most studies on DAS focus on optimizing single-route systems,where each area is exclusively served by one route and heuristic pre-assignations of requests are made.In contrast,our study addresses a more generalized routing and request selection problem for a DAS with multiple service routes.This problem jointly assigns requests to the service routes and determines the resulting routes while considering the pickup and delivery locations and the reserved boarding time for each request.A mixed-integer linear programming(MILP)model is developed to minimize the sum of bus travel time cost,passenger in-vehicle and waiting time costs,and request rejection penalties.A tailored adaptive large neighborhood search algorithm(ALNS)solves this optimization model efficiently.The numerical experiments show that,under the same optimality conditions,the proposed algorithm outperforms the exact algorithm implemented by GORUBI in terms of solution quality and computation time.The ALNS algorithm also reports cost reductions of up to 50%in comparison with prevailing benchmark metaheuristics.Moreover,the multi-route DAS in this paper has a lower rejection rate and objective value than the single-route systems examined in previous studies.展开更多
基金Projects(61304203,51409157)supported by the National Natural Science Foundation of ChinaProject(12ZR1444800)supported by the Natural Science Foundation of Shanghai,China
文摘This work considers those road networks in which there are multi-route choices for bifurcation-destination(or origin-destination) pairs, and designs a real-time variable message sign(VMS)-based routing control strategy in the model predictive control(MPC) framework. The VMS route recommendation provided by the traffic management authority is directly considered as the control variable, and the routing control model is established, in which a multi-dimensional control vector is introduced to describe the influence of route recommendations on flow distribution. In the MPC framework, a system optimum routing strategy with the constraints regarding drivers' acceptability with recommended routes is designed, which can not only meet the traffic management authority's control requirement but also improve drivers' satisfaction with the route guidance system. The simulation carried out shows that the proposed routing control can effectively mitigate traffic congestion, reduces followers' time delay, and improves drivers' satisfaction with routing control in road networks.
文摘In an ad hoc network, it is usually difficult to optimize the assignment of network routing resources using a single type of routing protocol due to the differences in network scale, node moving mode and node distribution. Therefore, it is desirable to have nodes run multiple routing protocols simultaneously so that more than one protocols can be chosen to work jointly. For this purpose, a multiple routing platform for Ad hoc networks is proposed on a higher level of current routing protocols. In order to ensure the security of the platform, a security mechanism and its formal analysis by BAN logic is given. The simulation results of the network performance demonstrate that the proposed multi-routing platform is practicable in some complex applications.
文摘This paper attempts to optimize optimal capacities, block routing and mine sequencing problems in a mining system. The solution approach is based on a heuristics and the mixed integer programming (MIP). Unlike previous sequential solution approaches, the problems are herein solved at the same time. Furthermore, the proposed approach guarantees practical solutions because it considers ore material distribution within orebody. The paper has two main contributions: (a) the proposed approach generates production rates in a manner that the capacities are satisfied; (b) the proposed approach does not use pre-defined marginal cut-off grades. Thus, idle capacity problem is eliminated and different scheduling combinations are allowed. To see the performance of the approach proposed, a case study is carried out using a gold data. The schedule generated shows that the approach can determine optimal production rates, block destination and sequencing effectively.
基金supported by the National Natural Science Foundation of China(Grant Nos.72371130 and 72001108).
文摘The demand-adaptive system(DAS)has been recognized as a promising transit mode for demand with high fluctuations.In this paper,we optimize the routes and request selection for a DAS with multiple service routes.Currently,most studies on DAS focus on optimizing single-route systems,where each area is exclusively served by one route and heuristic pre-assignations of requests are made.In contrast,our study addresses a more generalized routing and request selection problem for a DAS with multiple service routes.This problem jointly assigns requests to the service routes and determines the resulting routes while considering the pickup and delivery locations and the reserved boarding time for each request.A mixed-integer linear programming(MILP)model is developed to minimize the sum of bus travel time cost,passenger in-vehicle and waiting time costs,and request rejection penalties.A tailored adaptive large neighborhood search algorithm(ALNS)solves this optimization model efficiently.The numerical experiments show that,under the same optimality conditions,the proposed algorithm outperforms the exact algorithm implemented by GORUBI in terms of solution quality and computation time.The ALNS algorithm also reports cost reductions of up to 50%in comparison with prevailing benchmark metaheuristics.Moreover,the multi-route DAS in this paper has a lower rejection rate and objective value than the single-route systems examined in previous studies.
