近年来,极端高温干旱等灾害事件频发,给经济和社会带来巨大影响,尤其是2022年夏季,我国中东部地区遭遇了持续性高温和严重干旱,造成了严重经济损失。标准化加权平均降水(Standardized Weighted Average Precipitation,SWAP)指数基于简...近年来,极端高温干旱等灾害事件频发,给经济和社会带来巨大影响,尤其是2022年夏季,我国中东部地区遭遇了持续性高温和严重干旱,造成了严重经济损失。标准化加权平均降水(Standardized Weighted Average Precipitation,SWAP)指数基于简单物理模型,考虑前期降水的累积效应与衰减效应,能够准确地反映当前旱涝状况,并展现对应的演变过程。为了探究此次干旱事件的变化特征,本文将该方法与传统的标准化降水指数(Standardized Precipitation Index,SPI)进行对比,采用该方法对2022年夏季的干旱进行逐日监测,并结合游程理论,对干旱的极端程度进行了量化分析。结果表明:SWAP指数在逐日尺度上的监测效果更优,能够提供更为精确的干旱信息。本次事件中干旱首先出现在华北和东北地区,随后蔓延至西北和华南地区,最终在8月中旬大部分地区都呈现严重干旱的状态。此次干旱是近62 a以来最为极端的干旱事件,在不同阈值下,干旱日数、干旱日SWAP累积量和干旱强度均达到了历史最高水平。本研究为评估干旱事件的极端程度提供了新的方法,为未来干旱的监测、预警及气候灾害的管理与应对提供了科学依据与技术支持。展开更多
The valuation of financial derivatives often assumes risk neutrality with respect to the risk-neutral martingale measure,which prevents arbitrage opportunities.However,casual traders may still incur substantial losses...The valuation of financial derivatives often assumes risk neutrality with respect to the risk-neutral martingale measure,which prevents arbitrage opportunities.However,casual traders may still incur substantial losses when trading at this risk-neutral price,especially when the price has to be paid now and the payoff is only realized in the future.This study proposes a new valuation framework that provides risksensitive investors with an additional safeguard.The proposed framework embraces a worst-case perspective while exploiting the underlier’s stochastic process,representing a combination of robust optimization and stochastic programming.Notably,it aims to mitigate losses in the likelier scenarios of the underlying asset’s prices.When the underlier’s returns are independent and lognormally but not necessarily identically distributed,our approach for pricing variance and volatility swaps could be greatly simplified,benefit from parallel computing,and be solved by a two-dimensional grid search.We further derive a closed-form solution in some special stationary cases and provide experimental results to highlight the effect of risk aversion on fending off sizable trading losses.展开更多
The implementation of the standard is expected to help electric vehicle battery swap stations to adapt to diversified needs and vehicle models,promoting the industry’s orderly and healthy development.
In this paper,we propose a perfect entanglement swapping protocol for generating a shared three-qubit W state between two remote parties in a deterministic manner.Our method offers a reliable alternative to existing p...In this paper,we propose a perfect entanglement swapping protocol for generating a shared three-qubit W state between two remote parties in a deterministic manner.Our method offers a reliable alternative to existing probabilistic protocols for W state entanglement swapping,which is crucial for various quantum information processing tasks.We present a detailed quantum circuit design,implemented using the Qiskit simulator,that outlines the preparation of W states and the execution of joint measurements required for the entanglement swapping process.Furthermore,we analyze the effects of imperfect operations and noisy communication channels on the fidelity of the resulting shared W state.To address these challenges,we introduce a weak measurement-based purification method that enhances fidelity in the presence of amplitude damping.Through mathematical analysis and Qiskit simulations,we demonstrate the effectiveness of our proposed protocol,offering a practical solution for high-fidelity W state generation in real-world quantum communication scenarios.展开更多
In this work,Langevin dynamics simulations were carried out to thoroughly investigate the swapping process of composite knots under tension in a cuboid nanochannel.From our analysis,the free energy profiles of knot sw...In this work,Langevin dynamics simulations were carried out to thoroughly investigate the swapping process of composite knots under tension in a cuboid nanochannel.From our analysis,the free energy profiles of knot swapping under different conditions were extracted from the overall probability distribution of the relative distance between the centers of composite knots.In addition,the impact of the stretching force,confinement size,and bending stiffness on the free energy profiles was directly identified.Especially,the influence of topology structure is for the first time reported.The increasing stretching force in a fixed confinement or the confinement size under a constant stretching force does not alter their respective equilibrium populations at the separate state and the entangled state.In contrast,a bending stiffness larger than 15 enhanced the formation of the entangled state.The topology structure of the 51knot,which was different from the 52knot,resulted in forming a metastable state in the free energy profiles.The increasing stretching forces yielded an enhancement of the following free energy barrier.展开更多
In March 2025,prominent Chinese automaker NIO(Shanghai,China),the global leader in electric vehicle(EV)battery swapping,and Contemporary Amperex Technology Co.,Ltd.(CATL)(Nindge,China),the world’s biggest manufacture...In March 2025,prominent Chinese automaker NIO(Shanghai,China),the global leader in electric vehicle(EV)battery swapping,and Contemporary Amperex Technology Co.,Ltd.(CATL)(Nindge,China),the world’s biggest manufacturer of EV batteries,announced a strategic partnership to build the world’s largest battery swapping network,while also promoting unified standards and technologies[1].Just weeks later,CATL announced another partnership,this one with Chinese state-owned oil giant Sinopec(Beijing,China)to build 10000 new battery swapping stations in China,at least 500 in 2025[2].展开更多
Automated guided vehicles(AGVs)are key equipment in automated container terminals(ACTs),and their operational efficiency can be impacted by conflicts and battery swapping.Additionally,AGVs have bidirectional transport...Automated guided vehicles(AGVs)are key equipment in automated container terminals(ACTs),and their operational efficiency can be impacted by conflicts and battery swapping.Additionally,AGVs have bidirectional transportation capabilities,allowing them tomove in the opposite directionwithout turning around,which helps reduce transportation time.This paper aims at the problem of AGV scheduling and bidirectional conflict-free routing with battery swapping in automated terminals.A bi-level mixed integer programming(MIP)model is proposed,taking into account task assignment,bidirectional conflict-free routing,and battery swapping.The upper model focuses on container task assignment and AGV battery swapping planning,while the lower model ensures conflict-free movement of AGVs.A double-threshold battery swapping strategy is introduced,allowing AGVs to utilize waiting time for loading for battery swapping.An improved differential evolution variable neighborhood search(IDE-VNS)algorithm is developed to solve the bi-level MIP model,aiming to minimize the completion time of all jobs.Experimental results demonstrate that compared to the differential evolution(DE)algorithm and the genetic algorithm(GA),the IDEVNS algorithmreduces fitness values by 44.49% and 45.22%,though it does increase computation time by 56.28% and 62.03%,respectively.Bidirectional transportation reduces the fitness value by an average of 10.97% when the container scale is small.As the container scale increases,the fitness value of bidirectional transportation gradually approaches that of unidirectional transportation.The results further show that the double-threshold battery swapping strategy enhances AGV utilization and reduces the fitness value.展开更多
基金supported by the Ministry of Education,Singapore,under its Academic Research Fund Tier 2 Grant MOE-T2EP20222-0003.
文摘The valuation of financial derivatives often assumes risk neutrality with respect to the risk-neutral martingale measure,which prevents arbitrage opportunities.However,casual traders may still incur substantial losses when trading at this risk-neutral price,especially when the price has to be paid now and the payoff is only realized in the future.This study proposes a new valuation framework that provides risksensitive investors with an additional safeguard.The proposed framework embraces a worst-case perspective while exploiting the underlier’s stochastic process,representing a combination of robust optimization and stochastic programming.Notably,it aims to mitigate losses in the likelier scenarios of the underlying asset’s prices.When the underlier’s returns are independent and lognormally but not necessarily identically distributed,our approach for pricing variance and volatility swaps could be greatly simplified,benefit from parallel computing,and be solved by a two-dimensional grid search.We further derive a closed-form solution in some special stationary cases and provide experimental results to highlight the effect of risk aversion on fending off sizable trading losses.
文摘The implementation of the standard is expected to help electric vehicle battery swap stations to adapt to diversified needs and vehicle models,promoting the industry’s orderly and healthy development.
基金supported by the National Natural Science Foundation of China under Grant No.62473354.
文摘In this paper,we propose a perfect entanglement swapping protocol for generating a shared three-qubit W state between two remote parties in a deterministic manner.Our method offers a reliable alternative to existing probabilistic protocols for W state entanglement swapping,which is crucial for various quantum information processing tasks.We present a detailed quantum circuit design,implemented using the Qiskit simulator,that outlines the preparation of W states and the execution of joint measurements required for the entanglement swapping process.Furthermore,we analyze the effects of imperfect operations and noisy communication channels on the fidelity of the resulting shared W state.To address these challenges,we introduce a weak measurement-based purification method that enhances fidelity in the presence of amplitude damping.Through mathematical analysis and Qiskit simulations,we demonstrate the effectiveness of our proposed protocol,offering a practical solution for high-fidelity W state generation in real-world quantum communication scenarios.
基金The National Natural Science Foundation of China under Grant Nos.11864006,11874309,12164007,and 12204118。
文摘In this work,Langevin dynamics simulations were carried out to thoroughly investigate the swapping process of composite knots under tension in a cuboid nanochannel.From our analysis,the free energy profiles of knot swapping under different conditions were extracted from the overall probability distribution of the relative distance between the centers of composite knots.In addition,the impact of the stretching force,confinement size,and bending stiffness on the free energy profiles was directly identified.Especially,the influence of topology structure is for the first time reported.The increasing stretching force in a fixed confinement or the confinement size under a constant stretching force does not alter their respective equilibrium populations at the separate state and the entangled state.In contrast,a bending stiffness larger than 15 enhanced the formation of the entangled state.The topology structure of the 51knot,which was different from the 52knot,resulted in forming a metastable state in the free energy profiles.The increasing stretching forces yielded an enhancement of the following free energy barrier.
文摘In March 2025,prominent Chinese automaker NIO(Shanghai,China),the global leader in electric vehicle(EV)battery swapping,and Contemporary Amperex Technology Co.,Ltd.(CATL)(Nindge,China),the world’s biggest manufacturer of EV batteries,announced a strategic partnership to build the world’s largest battery swapping network,while also promoting unified standards and technologies[1].Just weeks later,CATL announced another partnership,this one with Chinese state-owned oil giant Sinopec(Beijing,China)to build 10000 new battery swapping stations in China,at least 500 in 2025[2].
基金supported by National Natural Science Foundation of China(No.62073212)Shanghai Science and Technology Commission(No.23ZR1426600).
文摘Automated guided vehicles(AGVs)are key equipment in automated container terminals(ACTs),and their operational efficiency can be impacted by conflicts and battery swapping.Additionally,AGVs have bidirectional transportation capabilities,allowing them tomove in the opposite directionwithout turning around,which helps reduce transportation time.This paper aims at the problem of AGV scheduling and bidirectional conflict-free routing with battery swapping in automated terminals.A bi-level mixed integer programming(MIP)model is proposed,taking into account task assignment,bidirectional conflict-free routing,and battery swapping.The upper model focuses on container task assignment and AGV battery swapping planning,while the lower model ensures conflict-free movement of AGVs.A double-threshold battery swapping strategy is introduced,allowing AGVs to utilize waiting time for loading for battery swapping.An improved differential evolution variable neighborhood search(IDE-VNS)algorithm is developed to solve the bi-level MIP model,aiming to minimize the completion time of all jobs.Experimental results demonstrate that compared to the differential evolution(DE)algorithm and the genetic algorithm(GA),the IDEVNS algorithmreduces fitness values by 44.49% and 45.22%,though it does increase computation time by 56.28% and 62.03%,respectively.Bidirectional transportation reduces the fitness value by an average of 10.97% when the container scale is small.As the container scale increases,the fitness value of bidirectional transportation gradually approaches that of unidirectional transportation.The results further show that the double-threshold battery swapping strategy enhances AGV utilization and reduces the fitness value.
