The dynamic traveling salesman problem(DTSP)is significant in logistics distribution in real-world applications in smart cities,but it is uncertain and difficult to solve.This paper proposes a scheme library-based ant...The dynamic traveling salesman problem(DTSP)is significant in logistics distribution in real-world applications in smart cities,but it is uncertain and difficult to solve.This paper proposes a scheme library-based ant colony optimization(ACO)with a two-optimization(2-opt)strategy to solve the DTSP efficiently.The work is novel and contributes to three aspects:problemmodel,optimization framework,and algorithmdesign.Firstly,in the problem model,traditional DTSP models often consider the change of travel distance between two nodes over time,while this paper focuses on a special DTSP model in that the node locations change dynamically over time.Secondly,in the optimization framework,the ACO algorithm is carried out in an offline optimization and online application framework to efficiently reuse the historical information to help fast respond to the dynamic environment.The framework of offline optimization and online application is proposed due to the fact that the environmental change inDTSPis caused by the change of node location,and therefore the newenvironment is somehowsimilar to certain previous environments.This way,in the offline optimization,the solutions for possible environmental changes are optimized in advance,and are stored in a mode scheme library.In the online application,when an environmental change is detected,the candidate solutions stored in the mode scheme library are reused via ACO to improve search efficiency and reduce computational complexity.Thirdly,in the algorithm design,the ACO cooperates with the 2-opt strategy to enhance search efficiency.To evaluate the performance of ACO with 2-opt,we design two challenging DTSP cases with up to 200 and 1379 nodes and compare them with other ACO and genetic algorithms.The experimental results show that ACO with 2-opt can solve the DTSPs effectively.展开更多
Though secondary aqueous Zn ion batteries(AZIBs)have been received broad concern in recent years,the development of suitable cathode materials of AZIBs is still a big challenge.The MnO_(2) has been deemed as one of mo...Though secondary aqueous Zn ion batteries(AZIBs)have been received broad concern in recent years,the development of suitable cathode materials of AZIBs is still a big challenge.The MnO_(2) has been deemed as one of most hopeful cathode materials of AZIBs on account of some extraordinary merits,such as richly natural resources,low toxicity,high discharge potential,and large theoretical capacity.However,the crystal structure diversity of MnO_(2) results in an obvious various of charge storage mechanisms,which can cause great differences in electrochemical performance.Furthermore,several challenges,including intrinsic poor conductivity,dissolution of manganese and sluggish ion transport dynamics should be conquered before real practice.This work focuses on the reaction mechanisms and recent progress of MnO_(2)-based materials of AZIBs.In this review,a detailed review of the reaction mechanisms and optimal ways for enhancing electrochemical performance for MnO_(2)-based materials is proposed.At last,a number of viewpoints on challenges,future development direction,and foreground of MnO_(2)-based materials of aqueous zinc ions batteries are put forward.This review clarifies reaction mechanism of MnO_(2)-based materials of AZIBs,and offers a new perspective for the future invention in MnO_(2)-based cathode materials,thus accelerate the extensive development and commercialization practice of aqueous zinc ions batteries.展开更多
The ability of a novel nonionic CO2 -soluble surfactant to propagate foam in porous media was compared with that of a conventional anionic surfactant（aqueous soluble only）through core floods with Berea sandstone cor...The ability of a novel nonionic CO2 -soluble surfactant to propagate foam in porous media was compared with that of a conventional anionic surfactant（aqueous soluble only）through core floods with Berea sandstone cores.Both simultaneous and alternating injections have been tested.The novel foam outperforms the conventional one with respect to faster foam propagation and higher desaturation rate.Furthermore,the novel injection strategy,CO2 continuous injection with dissolved CO2 -soluble surfactant,has been tested in the laboratory.Strong foam presented without delay.It is the first time the measured surfactant properties have been used to model foam transport on a field scale to extend our findings with the presence of gravity segregation.Different injection strategies have been tested under both constant rate and pressure constraints.It was showed that novel foam outperforms the conventional one in every scenario with much higher sweep efficiency and injectivity as well as more even pressure redistribution.Also,for this novel foam,it is not necessary that constant pressure injection is better,which has been concluded in previous literature for conventional foam.Furthermore,the novel injection strategy,CO2 continuous injection with dissolved CO2 -soluble surfactant,gave the best performance,which could lower the injection and water treatment cost.展开更多
Background:The current outbreak of novel coronavirus disease 2019 has caused a seriousdisease burden worldwide.Vaccines are an important factor to sustain the epidemic.Although with a relatively high-vaccination world...Background:The current outbreak of novel coronavirus disease 2019 has caused a seriousdisease burden worldwide.Vaccines are an important factor to sustain the epidemic.Although with a relatively high-vaccination worldwide,the decay of vaccine efficacy andthe arising of new variants lead us to the challenge of maintaining a sufficient immunebarrier to protect the population.Method:A case-contact tracking data in Hunan,China,is used to estimate the contactpattern of cases for scenarios including school,workspace,etc,rather than ordinary susceptible population.Based on the estimated vaccine coverage and efficacy,a multi-groupvaccinated-exposed-presymptomatic-symptomatic-asymptomatic-removed model(VEFIAR)with 8 age groups,with each partitioned into 4 vaccination status groups isdeveloped.The optimal dose-wise vaccinating strategy is optimized based on the currentlyestimated immunity barrier of coverage and efficacy,using the greedy algorithm thatminimizes the cumulative cases,population size of hospitalization and fatality respectivelyin a certain future interval.Parameters of Delta and Omicron variants are used respectivelyin the optimization.Results:The estimated contact matrices of cases showed a concentration on middle ages,and has compatible magnitudes compared to estimations from contact surveys in otherstudies.The VEFIAR model is numerically stable.The optimal controled vaccination strategy requires immediate vaccination on the un-vaccinated high-contact population of age30e39 to reduce the cumulative cases,and is stable with different basic reproductionnumbers(R_(0)).As for minimizing hospitalization and fatality,the optimized strategy requires vaccination on the un-vaccinated of both aged 30e39 of high contact frequencyand the vulnerable older.Conclusion:The objective of reducing transmission requires vaccination in age groups ofthe highest contact frequency,with more priority for un-vaccinated than un-fully or fullyvaccinated.The objective of reducing total hospitalization and fatality requires not only toreduce transmission but also to protect the vulnerable older.The priority changes byvaccination progress.For any region,if the local contact pattern is available,then with thevaccination coverage,efficacy,and disease characteristics of relative risks in heterogeneouspopulations,the optimal dose-wise vaccinating process will be obtained and gives hintsfor decision-making.展开更多
ype-1 fuzzy sets cannot fully handle the uncertainties. To overcome the problem, type2 fuzzy sets have been proposed. The novelty of this paper is using interval type-2 fuzzy logic controller （IT2FLC） to control a f...ype-1 fuzzy sets cannot fully handle the uncertainties. To overcome the problem, type2 fuzzy sets have been proposed. The novelty of this paper is using interval type-2 fuzzy logic controller （IT2FLC） to control a flexible-joint robot with voltage control strategy. In order to take into account the whole robotic system including the dynamics of actuators and the robot manipulator, the voltages of motors are used as inputs of the system. To highlight the capabilities of the control system, a flexible joint robot which is highly nonlinear, heavily coupled and uncertain is used. In addition, to improve the control performance, the parameters of the primary membership functions of IT2FLC are optimized using particle swarm optimization （PSO）. A comparative study between the proposed IT2FLC and type-1 fuzzy logic controller （T1FLC） is presented to better assess their respective performance in presence of external disturbance and unmodelled dynamics. Stability analysis is presented and the effectiveness of the proposed control approach is demonstrated by simulations using a two-link flexible-joint robot driven by permanent magnet direct current motors. Simulation results show the superiority of the IT2FLC over the T1FLC in terms of accuracy, robustness and interpretability.展开更多
多台无人机协同完成野外传感器数据采集的工作中,建立具有精确能耗模型的多无人机路径规划问题模型尤为重要。提出了带转角能耗多无人机路径规划问题(multi-UAV path planning with angular energy consumption,MUPP-AEC)模型,该模型考...多台无人机协同完成野外传感器数据采集的工作中,建立具有精确能耗模型的多无人机路径规划问题模型尤为重要。提出了带转角能耗多无人机路径规划问题(multi-UAV path planning with angular energy consumption,MUPP-AEC)模型,该模型考虑了无人机在加速、减速、匀速、转角等飞行条件下的能耗差异。针对MUPP-AEC的特点,提出目标空间聚类离散头脑风暴优化算法(discrete brain storm optimization algorithm in objective space,DBSO-OS)。该算法采用个体空间整数编码和带2-opt的分阶段贪婪法解码策略,并对扰动算子和个体更新算子进行了离散化定义。个体更新算子中采用了混合随机反转变换和部分匹配变换的生成策略。实验结果表明:DBSO-OS能有效地求解MUPP-AEC;所提离散头脑风暴算子在全局收敛能力、求解精度和稳定性等方面均优于传统头脑风暴算子;在中小规模测试算例和较大规模测试算例的测试中,DBSO-OS优于对比算法。展开更多
This paper discusses the parallel computing of the third generation Ocean General Circulation Model (OGCM) from the State Key Laboratory of Numerical Modeling for Atmospheric Science and Geophysical Fluid Dynamics(LAS...This paper discusses the parallel computing of the third generation Ocean General Circulation Model (OGCM) from the State Key Laboratory of Numerical Modeling for Atmospheric Science and Geophysical Fluid Dynamics(LASG),Institute of Atmosphere Physics(IAP). Meanwhile, several optimization strategies for parallel computing of OGCM (POGCM) on Scalable Shared Memory Multiprocessor (S2MP) are presented. Using Message Passing Interface (MPI), we obtain super linear speedup on SGI Origin 2000 for parallel OGCM(POGCM) after optimization.展开更多
In this paper,a sensitivity matrix based approach is proposed to improve the minimum damping ratio.The proposed method also avoids burdensome deviation calculations of damping ratio of large-scale power grids when com...In this paper,a sensitivity matrix based approach is proposed to improve the minimum damping ratio.The proposed method also avoids burdensome deviation calculations of damping ratio of large-scale power grids when compared to the Small-Signal-Stability Constrained Optimal Power Flow(SSSC-OPF)approach.This is achieved using the Matrix Perturbation Theory(MPT)to deal with the 2nd order sensitivity matrices,and the establishment of an optimal corrective control model to regulate the output power of generating units to improve the minimum damping ratio of power grids.Finally,simulation results on the IEEE 9-bus,IEEE 39-bus and a China 634-bus systems show that the proposed approach can significantly reduce the burden of deviation calculation,while enhancing power system stability and ensuring calculation accuracy.展开更多
基金supported in part by the National Research Foundation of Korea (NRF-2021H1D3A2A01082705).
文摘The dynamic traveling salesman problem(DTSP)is significant in logistics distribution in real-world applications in smart cities,but it is uncertain and difficult to solve.This paper proposes a scheme library-based ant colony optimization(ACO)with a two-optimization(2-opt)strategy to solve the DTSP efficiently.The work is novel and contributes to three aspects:problemmodel,optimization framework,and algorithmdesign.Firstly,in the problem model,traditional DTSP models often consider the change of travel distance between two nodes over time,while this paper focuses on a special DTSP model in that the node locations change dynamically over time.Secondly,in the optimization framework,the ACO algorithm is carried out in an offline optimization and online application framework to efficiently reuse the historical information to help fast respond to the dynamic environment.The framework of offline optimization and online application is proposed due to the fact that the environmental change inDTSPis caused by the change of node location,and therefore the newenvironment is somehowsimilar to certain previous environments.This way,in the offline optimization,the solutions for possible environmental changes are optimized in advance,and are stored in a mode scheme library.In the online application,when an environmental change is detected,the candidate solutions stored in the mode scheme library are reused via ACO to improve search efficiency and reduce computational complexity.Thirdly,in the algorithm design,the ACO cooperates with the 2-opt strategy to enhance search efficiency.To evaluate the performance of ACO with 2-opt,we design two challenging DTSP cases with up to 200 and 1379 nodes and compare them with other ACO and genetic algorithms.The experimental results show that ACO with 2-opt can solve the DTSPs effectively.
基金supported by the National Natural Science Foundation of China(U1960107)the Natural Science Foundation of Hebei Province(E2022501014)+4 种基金the"333"Talent Project of Hebei Province(A202005018)the Fundamental Research Funds for the Central Universities(N2123001)the Science and Technology Research Youth Fund Project of Higher Education Institutions of Hebei Province(QN2022196)the 2023 Hebei Provincial Postgraduate Student Innovation Ability training funding project(CXZZSS2023196)the Performance subsidy fund for Key Laboratory of Dielectric and Electrolyte Functional Material Hebei Province(22567627H)。
文摘Though secondary aqueous Zn ion batteries(AZIBs)have been received broad concern in recent years,the development of suitable cathode materials of AZIBs is still a big challenge.The MnO_(2) has been deemed as one of most hopeful cathode materials of AZIBs on account of some extraordinary merits,such as richly natural resources,low toxicity,high discharge potential,and large theoretical capacity.However,the crystal structure diversity of MnO_(2) results in an obvious various of charge storage mechanisms,which can cause great differences in electrochemical performance.Furthermore,several challenges,including intrinsic poor conductivity,dissolution of manganese and sluggish ion transport dynamics should be conquered before real practice.This work focuses on the reaction mechanisms and recent progress of MnO_(2)-based materials of AZIBs.In this review,a detailed review of the reaction mechanisms and optimal ways for enhancing electrochemical performance for MnO_(2)-based materials is proposed.At last,a number of viewpoints on challenges,future development direction,and foreground of MnO_(2)-based materials of aqueous zinc ions batteries are put forward.This review clarifies reaction mechanism of MnO_(2)-based materials of AZIBs,and offers a new perspective for the future invention in MnO_(2)-based cathode materials,thus accelerate the extensive development and commercialization practice of aqueous zinc ions batteries.
文摘The ability of a novel nonionic CO2 -soluble surfactant to propagate foam in porous media was compared with that of a conventional anionic surfactant（aqueous soluble only）through core floods with Berea sandstone cores.Both simultaneous and alternating injections have been tested.The novel foam outperforms the conventional one with respect to faster foam propagation and higher desaturation rate.Furthermore,the novel injection strategy,CO2 continuous injection with dissolved CO2 -soluble surfactant,has been tested in the laboratory.Strong foam presented without delay.It is the first time the measured surfactant properties have been used to model foam transport on a field scale to extend our findings with the presence of gravity segregation.Different injection strategies have been tested under both constant rate and pressure constraints.It was showed that novel foam outperforms the conventional one in every scenario with much higher sweep efficiency and injectivity as well as more even pressure redistribution.Also,for this novel foam,it is not necessary that constant pressure injection is better,which has been concluded in previous literature for conventional foam.Furthermore,the novel injection strategy,CO2 continuous injection with dissolved CO2 -soluble surfactant,gave the best performance,which could lower the injection and water treatment cost.
基金supported by the National Key Research and Development Program of China(2021YFC2301604)the Research Project on Education and Teaching Reform of Undergraduate Universities of Fujian Province,China(FBJG20210260)+2 种基金the Self-supporting Program of Guangzhou Laboratory(Grant No.SRPG22-007)the Bill&Melinda Gates Foundation(Grant INV-005834 to T.C.)the Research on the Precise Prevention and Control System of SARS-Cov-2(Grant No.35022022YJ07,Topic No.2022YJ-3).
文摘Background:The current outbreak of novel coronavirus disease 2019 has caused a seriousdisease burden worldwide.Vaccines are an important factor to sustain the epidemic.Although with a relatively high-vaccination worldwide,the decay of vaccine efficacy andthe arising of new variants lead us to the challenge of maintaining a sufficient immunebarrier to protect the population.Method:A case-contact tracking data in Hunan,China,is used to estimate the contactpattern of cases for scenarios including school,workspace,etc,rather than ordinary susceptible population.Based on the estimated vaccine coverage and efficacy,a multi-groupvaccinated-exposed-presymptomatic-symptomatic-asymptomatic-removed model(VEFIAR)with 8 age groups,with each partitioned into 4 vaccination status groups isdeveloped.The optimal dose-wise vaccinating strategy is optimized based on the currentlyestimated immunity barrier of coverage and efficacy,using the greedy algorithm thatminimizes the cumulative cases,population size of hospitalization and fatality respectivelyin a certain future interval.Parameters of Delta and Omicron variants are used respectivelyin the optimization.Results:The estimated contact matrices of cases showed a concentration on middle ages,and has compatible magnitudes compared to estimations from contact surveys in otherstudies.The VEFIAR model is numerically stable.The optimal controled vaccination strategy requires immediate vaccination on the un-vaccinated high-contact population of age30e39 to reduce the cumulative cases,and is stable with different basic reproductionnumbers(R_(0)).As for minimizing hospitalization and fatality,the optimized strategy requires vaccination on the un-vaccinated of both aged 30e39 of high contact frequencyand the vulnerable older.Conclusion:The objective of reducing transmission requires vaccination in age groups ofthe highest contact frequency,with more priority for un-vaccinated than un-fully or fullyvaccinated.The objective of reducing total hospitalization and fatality requires not only toreduce transmission but also to protect the vulnerable older.The priority changes byvaccination progress.For any region,if the local contact pattern is available,then with thevaccination coverage,efficacy,and disease characteristics of relative risks in heterogeneouspopulations,the optimal dose-wise vaccinating process will be obtained and gives hintsfor decision-making.
文摘ype-1 fuzzy sets cannot fully handle the uncertainties. To overcome the problem, type2 fuzzy sets have been proposed. The novelty of this paper is using interval type-2 fuzzy logic controller （IT2FLC） to control a flexible-joint robot with voltage control strategy. In order to take into account the whole robotic system including the dynamics of actuators and the robot manipulator, the voltages of motors are used as inputs of the system. To highlight the capabilities of the control system, a flexible joint robot which is highly nonlinear, heavily coupled and uncertain is used. In addition, to improve the control performance, the parameters of the primary membership functions of IT2FLC are optimized using particle swarm optimization （PSO）. A comparative study between the proposed IT2FLC and type-1 fuzzy logic controller （T1FLC） is presented to better assess their respective performance in presence of external disturbance and unmodelled dynamics. Stability analysis is presented and the effectiveness of the proposed control approach is demonstrated by simulations using a two-link flexible-joint robot driven by permanent magnet direct current motors. Simulation results show the superiority of the IT2FLC over the T1FLC in terms of accuracy, robustness and interpretability.
文摘多台无人机协同完成野外传感器数据采集的工作中,建立具有精确能耗模型的多无人机路径规划问题模型尤为重要。提出了带转角能耗多无人机路径规划问题(multi-UAV path planning with angular energy consumption,MUPP-AEC)模型,该模型考虑了无人机在加速、减速、匀速、转角等飞行条件下的能耗差异。针对MUPP-AEC的特点,提出目标空间聚类离散头脑风暴优化算法(discrete brain storm optimization algorithm in objective space,DBSO-OS)。该算法采用个体空间整数编码和带2-opt的分阶段贪婪法解码策略,并对扰动算子和个体更新算子进行了离散化定义。个体更新算子中采用了混合随机反转变换和部分匹配变换的生成策略。实验结果表明:DBSO-OS能有效地求解MUPP-AEC;所提离散头脑风暴算子在全局收敛能力、求解精度和稳定性等方面均优于传统头脑风暴算子;在中小规模测试算例和较大规模测试算例的测试中,DBSO-OS优于对比算法。
基金Supported by National 86 3 Project(86 3-30 6 -ZD11)
文摘This paper discusses the parallel computing of the third generation Ocean General Circulation Model (OGCM) from the State Key Laboratory of Numerical Modeling for Atmospheric Science and Geophysical Fluid Dynamics(LASG),Institute of Atmosphere Physics(IAP). Meanwhile, several optimization strategies for parallel computing of OGCM (POGCM) on Scalable Shared Memory Multiprocessor (S2MP) are presented. Using Message Passing Interface (MPI), we obtain super linear speedup on SGI Origin 2000 for parallel OGCM(POGCM) after optimization.
基金This work was supported by the National Natural Science Foundation of China(Grant No.51577085).
文摘In this paper,a sensitivity matrix based approach is proposed to improve the minimum damping ratio.The proposed method also avoids burdensome deviation calculations of damping ratio of large-scale power grids when compared to the Small-Signal-Stability Constrained Optimal Power Flow(SSSC-OPF)approach.This is achieved using the Matrix Perturbation Theory(MPT)to deal with the 2nd order sensitivity matrices,and the establishment of an optimal corrective control model to regulate the output power of generating units to improve the minimum damping ratio of power grids.Finally,simulation results on the IEEE 9-bus,IEEE 39-bus and a China 634-bus systems show that the proposed approach can significantly reduce the burden of deviation calculation,while enhancing power system stability and ensuring calculation accuracy.
