This study employed a quantum-annealing framework to solve spacecraft trajectory optimization problems.Quantum annealing belongs to the field of quantum computing and is a promising technique for tackling hard binary ...This study employed a quantum-annealing framework to solve spacecraft trajectory optimization problems.Quantum annealing belongs to the field of quantum computing and is a promising technique for tackling hard binary optimization problems by employing quantum annealers.To address the optimal control of a trajectory using quantum annealing,a transcription procedure was introduced to express the problem in the binary optimization form required.The proposed procedure leverages the pseudospectral method to discretize the trajectory and represents the dynamical constraints as algebraic equality constraints at specific nodes.Subsequently,both a linearization procedure and binary representation strategy for the real-valued variables of the problem were presented,leading to the quadratic binary unconstrained optimization form.The quantum-annealing-based method was tested in the context of an interplanetary low-thrust transfer from the Earth to Mars.First,we discussed which instances of the problem,especially in terms of their dimensions,are implementable on currently available quantum annealers;then,a solution was sought by employing annealers from D-Wave systems.Solutions from hybrid solvers that combine classical and quantum resources,and fully quantum solvers were explored.The results demonstrate the validity of the transcription approach,demonstrate the ability of the hybrid solver to tackle the case-study problem,and highlight the promising features and current limitations of practical trajectory optimization with quantum annealing.展开更多
We detail some of the understudied aspects of the flow inside and around the Hexactinellid Sponge Euplectella aspergillum.By leveraging the flexibility of the Lattice Boltzmann Method,High Performance Computing simula...We detail some of the understudied aspects of the flow inside and around the Hexactinellid Sponge Euplectella aspergillum.By leveraging the flexibility of the Lattice Boltzmann Method,High Performance Computing simulations are performed to dissect the complex conditions corresponding to the actual environment at the bottom of the ocean,at depths between 100 and 1,000 m.These large-scale simulations unveil potential clues on the evolutionary adaptations of these deep-sea sponges in response to the surrounding fluid flow,and they open the path to future investigations at the interface between physics,engineering and biology.展开更多
This work focuses on the potential impacts of the autonomous vehicles in a mixed traffic condition represented in traffic simulator Simulation of Urban MObility(SUMO)with real traffic flow.Specifically,real traffic fl...This work focuses on the potential impacts of the autonomous vehicles in a mixed traffic condition represented in traffic simulator Simulation of Urban MObility(SUMO)with real traffic flow.Specifically,real traffic flow and speed data collected in 2002 and 2019 in Gothenburg were used to simulate daily flow variation in SUMO.In order to predict the most likely drawbacks during the transition from a traffic consisting only manually driven vehicles to a traffic consisting only fully-autonomous vehicles,this study focuses on mixed traffic with different percentages of autonomous and manually driven vehicles.To realize this aim,several parameters of the car following and lane change models of autonomous vehicles are investigated in this paper.Along with the fundamental diagram,the number of lane changes and the number of conflicts are analyzed and studied as measures for improving road safety and efficiency.The study highlights that the autonomous vehicles’features that improve safety and efficiency in 100%autonomous and mixed traffic are different,and the ability of autonomous vehicles to switch between mixed and autonomous driving styles,and vice versa depending on the scenario,is necessary.展开更多
基金funding provided by Universitádegli Studi di Roma La Sapienza within the CRUI-CARE Agreement.
文摘This study employed a quantum-annealing framework to solve spacecraft trajectory optimization problems.Quantum annealing belongs to the field of quantum computing and is a promising technique for tackling hard binary optimization problems by employing quantum annealers.To address the optimal control of a trajectory using quantum annealing,a transcription procedure was introduced to express the problem in the binary optimization form required.The proposed procedure leverages the pseudospectral method to discretize the trajectory and represents the dynamical constraints as algebraic equality constraints at specific nodes.Subsequently,both a linearization procedure and binary representation strategy for the real-valued variables of the problem were presented,leading to the quadratic binary unconstrained optimization form.The quantum-annealing-based method was tested in the context of an interplanetary low-thrust transfer from the Earth to Mars.First,we discussed which instances of the problem,especially in terms of their dimensions,are implementable on currently available quantum annealers;then,a solution was sought by employing annealers from D-Wave systems.Solutions from hybrid solvers that combine classical and quantum resources,and fully quantum solvers were explored.The results demonstrate the validity of the transcription approach,demonstrate the ability of the hybrid solver to tackle the case-study problem,and highlight the promising features and current limitations of practical trajectory optimization with quantum annealing.
基金G.F.acknowledges CINECA computational grant ISCRA-B IsB17–SPONGES,no.HP10B9ZOKQ and,partially,the support of PRIN projects CUP E82F16003010006(principal investigator,G.F.for the Tor Vergata Research Unit)and CUP E84I19001020006(principal investigator,G.Bella)support from the European Research Council under the Horizon 2020 Programme advanced grant agreement no.739964(‘COPMAT’)M.P.acknowledges the support of the National Science Foundation under grant no.CMMI 1901697.
文摘We detail some of the understudied aspects of the flow inside and around the Hexactinellid Sponge Euplectella aspergillum.By leveraging the flexibility of the Lattice Boltzmann Method,High Performance Computing simulations are performed to dissect the complex conditions corresponding to the actual environment at the bottom of the ocean,at depths between 100 and 1,000 m.These large-scale simulations unveil potential clues on the evolutionary adaptations of these deep-sea sponges in response to the surrounding fluid flow,and they open the path to future investigations at the interface between physics,engineering and biology.
文摘This work focuses on the potential impacts of the autonomous vehicles in a mixed traffic condition represented in traffic simulator Simulation of Urban MObility(SUMO)with real traffic flow.Specifically,real traffic flow and speed data collected in 2002 and 2019 in Gothenburg were used to simulate daily flow variation in SUMO.In order to predict the most likely drawbacks during the transition from a traffic consisting only manually driven vehicles to a traffic consisting only fully-autonomous vehicles,this study focuses on mixed traffic with different percentages of autonomous and manually driven vehicles.To realize this aim,several parameters of the car following and lane change models of autonomous vehicles are investigated in this paper.Along with the fundamental diagram,the number of lane changes and the number of conflicts are analyzed and studied as measures for improving road safety and efficiency.The study highlights that the autonomous vehicles’features that improve safety and efficiency in 100%autonomous and mixed traffic are different,and the ability of autonomous vehicles to switch between mixed and autonomous driving styles,and vice versa depending on the scenario,is necessary.
