Combined Heat and Power Economic Dispatch(CHPED)is an important problem in the energy field,and it is beneficial for improving the utilization efficiency of power and heat energies.This paper proposes a Modified Genet...Combined Heat and Power Economic Dispatch(CHPED)is an important problem in the energy field,and it is beneficial for improving the utilization efficiency of power and heat energies.This paper proposes a Modified Genetic Algorithm(MGA)to determine the power and heat outputs of three kinds of units for CHPED.First,MGA replaces the simulated binary crossover by a new one based on the uniform and guassian distributions,and its convergence can be enhanced.Second,MGA modi-fies the mutation operator by introducing a disturbance coefficient based on guassian distribution,which can decrease the risk of being trapped into local optima.Eight instances with or without prohibited operating zones are used to investigate the efficiencies of MGA and other four genetic algorithms for CHPED.In comparison with the other algorithms,MGA has reduced generation costs by at least 562.73$,1068.7$,522.68$and 1016.24$,respectively,for instances 3,4,7 and 8,and it has reduced generation costs by at most 848.22$,3642.85$,897.63$and 3812.65$,respectively,for instances 3,4,7 and 8.Therefore,MGA has desirable convergence and stability for CHPED in comparison with the other four genetic algorithms.展开更多
As a key to improve the performance of the interbay automated material handling system （AMHS） in 300 mm semiconductor wafer fabrication system, the real- time overhead hoist transport （OHT） dispatching problem has...As a key to improve the performance of the interbay automated material handling system （AMHS） in 300 mm semiconductor wafer fabrication system, the real- time overhead hoist transport （OHT） dispatching problem has received much attention. This problem is first formu- lated as a special form of assignment problem and it is proved that more than one solution will be obtained by Hungarian algorithm simultaneously. Through proposing and strictly proving two propositions related to the char- acteristics of these solutions, a modified Hungarian algo- rithm is designed to distinguish these solutions. Finally, a new real-time OHT dispatching method is carefully designed by implementing the solution obtained by the modified Hungarian algorithm. The experimental results of discrete event simulations show that, compared with con- ventional Hungarian algorithm dispatching method, the proposed dispatching method that chooses the solution with the maximum variance respectively reduces on average 4 s of the average waiting time and average lead time of wafer lots, and its performance is rather stable in multiple dif- ferent scenarios of the interbay AMHS with different quantities of shortcuts. This research provides an efficient real-time OHT dispatching mechanism for the interbay AMHS with shortcuts and bypasses.展开更多
Power generation dispatching is a large complex system problem with multi-dimensional and nonlinear characteristics. A mathematical model was established based on the principle of reservoir operation. A large quantity...Power generation dispatching is a large complex system problem with multi-dimensional and nonlinear characteristics. A mathematical model was established based on the principle of reservoir operation. A large quantity of optimal scheduling processes were obtained by calculating the daily runoff process within three typical years, and a large number of simulated daily runoff processes were obtained using the progressive optimality algorithm （POA） in combination with the genetic algorithm （GA）. After analyzing the optimal scheduling processes, the corresponding scheduling rules were determined, and the practical formulas were obtained. These rules can make full use of the rolling runoff forecast and carry out the rolling scheduling. Compared with the optimized results, the maximum relative difference of the annual power generation obtained by the scheduling rules is no more than 1%. The effectiveness and practical applicability of the scheduling rules are demonstrated by a case study. This study provides a new perspective for formulating the rules of power generation dispatching.展开更多
Operational strategies and matching algorithms are used to ensure the availability and efficient assignment of ride-hailing services.Such operational strategies may result in services that,rather than complement tradi...Operational strategies and matching algorithms are used to ensure the availability and efficient assignment of ride-hailing services.Such operational strategies may result in services that,rather than complement traditional public transport(PT)systems,compete with them in both market(demand)and road-space use(congestion).This paper introduces and evaluates real-time vehicle dispatching strategies that focus on the prioritization of PT use and the complementarity between PT and ride-hailing in multimodal trips.Utilizing a novel two-step ride-matching algorithm,these strategies aim at decreasing travelers'wait times and motivating the use of PT.The agent-based travel demand forecasting model MATSim is used to implement and test the proposed matching strategies in the study area of Metropolitan Melbourne,Australia.The proposed strategies outperform the original MATSim strategies(which follow a first-come,first-serve approach)regarding average vehicle kilometers traveled(VKT)per ride,number of multimodal trips that use ride-hailing and PT,and the overall PT mode share.The results indicate substantial improvements across all proposed strategies,with PT mode shares increasing by 3.3%–19.8%.A fleet size of 200 was identified as the optimal fleet size.Multimodal trips increased by 7%–13%for all proposed strategies at this fleet size,illustrating a substantial shift towards integrated transport modes.Additionally,VKT per ride decreased by approximately 30%–33%with the proposed strategies at this fleet size.We conclude that serving all ride-hailing requests on a first-come/first-serve basis creates system-level inefficiencies that can be overcome by prioritizing requests that cannot be served by PT and/or have an emergency nature.展开更多
基金supported by the National Natural Science Foundation of China(NSFC)under Grant 61873272,62073327in part by the Natural Science Foundation of Jiangsu Province under Grant BK20200086,BK20200631.
文摘Combined Heat and Power Economic Dispatch(CHPED)is an important problem in the energy field,and it is beneficial for improving the utilization efficiency of power and heat energies.This paper proposes a Modified Genetic Algorithm(MGA)to determine the power and heat outputs of three kinds of units for CHPED.First,MGA replaces the simulated binary crossover by a new one based on the uniform and guassian distributions,and its convergence can be enhanced.Second,MGA modi-fies the mutation operator by introducing a disturbance coefficient based on guassian distribution,which can decrease the risk of being trapped into local optima.Eight instances with or without prohibited operating zones are used to investigate the efficiencies of MGA and other four genetic algorithms for CHPED.In comparison with the other algorithms,MGA has reduced generation costs by at least 562.73$,1068.7$,522.68$and 1016.24$,respectively,for instances 3,4,7 and 8,and it has reduced generation costs by at most 848.22$,3642.85$,897.63$and 3812.65$,respectively,for instances 3,4,7 and 8.Therefore,MGA has desirable convergence and stability for CHPED in comparison with the other four genetic algorithms.
基金Supported by National Natural Science Foundation of China(Grant No.51275307)
文摘As a key to improve the performance of the interbay automated material handling system （AMHS） in 300 mm semiconductor wafer fabrication system, the real- time overhead hoist transport （OHT） dispatching problem has received much attention. This problem is first formu- lated as a special form of assignment problem and it is proved that more than one solution will be obtained by Hungarian algorithm simultaneously. Through proposing and strictly proving two propositions related to the char- acteristics of these solutions, a modified Hungarian algo- rithm is designed to distinguish these solutions. Finally, a new real-time OHT dispatching method is carefully designed by implementing the solution obtained by the modified Hungarian algorithm. The experimental results of discrete event simulations show that, compared with con- ventional Hungarian algorithm dispatching method, the proposed dispatching method that chooses the solution with the maximum variance respectively reduces on average 4 s of the average waiting time and average lead time of wafer lots, and its performance is rather stable in multiple dif- ferent scenarios of the interbay AMHS with different quantities of shortcuts. This research provides an efficient real-time OHT dispatching mechanism for the interbay AMHS with shortcuts and bypasses.
基金supported by the National Key Basic Research Development Program of China (Grant No. 2002CCA00700)
文摘Power generation dispatching is a large complex system problem with multi-dimensional and nonlinear characteristics. A mathematical model was established based on the principle of reservoir operation. A large quantity of optimal scheduling processes were obtained by calculating the daily runoff process within three typical years, and a large number of simulated daily runoff processes were obtained using the progressive optimality algorithm （POA） in combination with the genetic algorithm （GA）. After analyzing the optimal scheduling processes, the corresponding scheduling rules were determined, and the practical formulas were obtained. These rules can make full use of the rolling runoff forecast and carry out the rolling scheduling. Compared with the optimized results, the maximum relative difference of the annual power generation obtained by the scheduling rules is no more than 1%. The effectiveness and practical applicability of the scheduling rules are demonstrated by a case study. This study provides a new perspective for formulating the rules of power generation dispatching.
文摘Operational strategies and matching algorithms are used to ensure the availability and efficient assignment of ride-hailing services.Such operational strategies may result in services that,rather than complement traditional public transport(PT)systems,compete with them in both market(demand)and road-space use(congestion).This paper introduces and evaluates real-time vehicle dispatching strategies that focus on the prioritization of PT use and the complementarity between PT and ride-hailing in multimodal trips.Utilizing a novel two-step ride-matching algorithm,these strategies aim at decreasing travelers'wait times and motivating the use of PT.The agent-based travel demand forecasting model MATSim is used to implement and test the proposed matching strategies in the study area of Metropolitan Melbourne,Australia.The proposed strategies outperform the original MATSim strategies(which follow a first-come,first-serve approach)regarding average vehicle kilometers traveled(VKT)per ride,number of multimodal trips that use ride-hailing and PT,and the overall PT mode share.The results indicate substantial improvements across all proposed strategies,with PT mode shares increasing by 3.3%–19.8%.A fleet size of 200 was identified as the optimal fleet size.Multimodal trips increased by 7%–13%for all proposed strategies at this fleet size,illustrating a substantial shift towards integrated transport modes.Additionally,VKT per ride decreased by approximately 30%–33%with the proposed strategies at this fleet size.We conclude that serving all ride-hailing requests on a first-come/first-serve basis creates system-level inefficiencies that can be overcome by prioritizing requests that cannot be served by PT and/or have an emergency nature.
