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
This paper explores the effect of informed trading, heterogeneity investment and liquidity shocks on the valuation of credit default swaps(CDSs). Under the condition of asymmetric information, the informed trading pla...This paper explores the effect of informed trading, heterogeneity investment and liquidity shocks on the valuation of credit default swaps(CDSs). Under the condition of asymmetric information, the informed trading plays an important role in the valuation of CDS. Instruction order flow has a significant influence on CDS price.And the scope of influence changes in accordance with different time interval, company status and the size of bid-ask spread. Heterogeneity of investors seriously affects the market liquidity and subsequently affects the CDS price. The bigger heterogeneity of the investment philosophy, investment habits, investment preference and so on is the bigger risk for market liquidity, and the higher price for CDS shall be. On the contrary, the conclusion is also consistent. The effectiveness of liquidity, whether it is before or after the financial crisis, dominates the fluctuation of CDS price. The premium of liquidity accounts for 36% to 50% of the CDS price.展开更多
The effects of stochastic volatility,jump clustering,and regime switching are considered when pricing variance swaps.This study established a two-stage procedure that simplifies the derivation by first isolating the r...The effects of stochastic volatility,jump clustering,and regime switching are considered when pricing variance swaps.This study established a two-stage procedure that simplifies the derivation by first isolating the regime switching from other stochastic sources.Based on this,a novel probabilistic approach was employed,leading to pricing formulas with time-dependent and regime-switching parameters.The formulated solutions were easy to implement and differed from most existing results of variance swap pricing,where Fourier inversion or fast Fourier transform must be performed to obtain the final results,since they are completely analytical without involving integrations.The numerical results indicate that jump clustering and regime switching have a significant influence on variance swap prices.展开更多
The use of credit default swaps （CDSs） has become increasingly popular over time. Between 2002 and 2007, gross notional amounts outstanding grew from below S2 trillion to nearly S60 trillion. The recent crisis has r...The use of credit default swaps （CDSs） has become increasingly popular over time. Between 2002 and 2007, gross notional amounts outstanding grew from below S2 trillion to nearly S60 trillion. The recent crisis has revealed several shortcomings in CDS market practices and structure. In addition, management of counterparty risk has proved insufficient, as has in some instances the settlement of contracts following a credit event. However, past problems should not distract from the potential benefits of these instruments. In particular, CDSs help complete markets, as they provide an effective means to hedge and trade credit risk. CDSs allow financial institutions to better manage their exposures, and investors benefit from an enhanced investment universe. The purpose of this paper is to present a complete and practical exposition of the CDS market and to explore how the development of the CDS market has played an important role in the credit risk markets. Currently, the CDS market is transforming into a more stable system. Various measures are being put in place to help enhance market transparency and mitigate operational and systemic risk. In particular, central counterparties have started to operate, which will eventually lead to an improved management of individual as well as system-wide risks.展开更多
Pricing variance swaps under stochastic volatility has been an important subject pursued recently. Various approaches have been proposed, mainly due to the substantially increased trading activities of volatility-rela...Pricing variance swaps under stochastic volatility has been an important subject pursued recently. Various approaches have been proposed, mainly due to the substantially increased trading activities of volatility-related derivatives in the past few years. In this note, the authors develop analytical method for pricing variance swaps under stochastic volatility with an Ornstein-Uhlenbeck(OU) process. By using Fourier transform algorithm, a closed-form solution for pricing variance swaps with stochastic volatility is obtained, and to give a comparison of fair strike value based on the discrete model, continuous model, and the Monte Carlo simulations.展开更多
Each morning at Yangluo Port in Wuhan,Hubei Province,the all-electric cargo vessel Huahang Xinneng No.1 completes a battery swap in under 10 minutes before returning to service with nearly 8,000 kWh of power onboard。
This study investigates the determinants that drive the volatility of the credit default swaps(CDS)of BRICIT(Brazil,Russia,India,China,Indonesia,and Turkey)nations as a proxy measure for sovereign risk.On the existenc...This study investigates the determinants that drive the volatility of the credit default swaps(CDS)of BRICIT(Brazil,Russia,India,China,Indonesia,and Turkey)nations as a proxy measure for sovereign risk.On the existence of cointegration,an unrestricted error correction model integrated with the autoregressive distributed lag(ARDL)model is applied to measure the short-run and long-run dynamics empirically.The study utilizes the Bayesian global vector autoregression methodology for cross-border spillover estimation.The study also suggests a strategy for policymakers for quadrant categorization to mitigate risk arising from cross-border spillover.The result of ARDL indicates that the global macroeconomic variables affect the BRICIT CDS more than domestic macroeconomic determinants,with Indian CDS being the most sensitive to Fed tapering.Notably,China’s CDS is the most sensitive to shocks,with the CDS volatility primarily driven by China’s geopolitical risk.Russian CDS is more sensitive to real effective exchange rates due to severe ruble depreciation than crude oil,despite Russia being a major oil exporter.The quadrant categorization indicates that the Indonesian stock market index is most interconnected with BRICIT CDS,while the Turkish long-term interest rates send the highest intensity spillover across BRICIT nations.展开更多
Working memory is a core cognitive function that supports goal-directed behavior and complex thought.We developed a spatial working memory and attention test on paired symbols(SWAPS)which has been proved to be a usefu...Working memory is a core cognitive function that supports goal-directed behavior and complex thought.We developed a spatial working memory and attention test on paired symbols(SWAPS)which has been proved to be a useful and valid tool for spatial working memory and attention studies in the fields of cognitive psychology,education,and psychiatry.The repeated administration of working memory capacity tests is common in clinical and research settings.Studies suggest that repeated cognitive tests may improve the performance scores also known as retest effects.The systematic investigation of retest effects in SWAPS is critical for interpreting scientific results,but it is still not fully developed.To address this,we recruited 77 college students aged 18–21 years and used SWAPS comprising 72 trials with different memory loads,learning time,and delay span.We repeated the test once a week for five weeks to investigate the retest effects of SWAPS.There were significant retest effects in the first two tests:the accuracy of the SWAPS tests significantly increased,and then stabilized.These findings provide useful information for researchers to appropriately use or interpret the repeated working memory tests.Further experiments are still needed to clarify the factors that mediate the retest effects,and find out the cognitive mechanism that influences the retest effects.展开更多
Implementing quantum wireless multi-hop network communication is essential to improve the global quantum network system. In this paper, we employ eight-level GHZ states as quantum channels to realize multi-hop quantum...Implementing quantum wireless multi-hop network communication is essential to improve the global quantum network system. In this paper, we employ eight-level GHZ states as quantum channels to realize multi-hop quantum communication, and utilize the logical relationship between the measurements of each node to derive the unitary operation performed by the end node. The hierarchical simultaneous entanglement switching(HSES) method is adopted, resulting in a significant reduction in the consumption of classical information compared to multi-hop quantum teleportation(QT)based on general simultaneous entanglement switching(SES). In addition, the proposed protocol is simulated on the IBM Quantum Experiment platform(IBM QE). Then, the data obtained from the experiment are analyzed using quantum state tomography, which verifies the protocol's good fidelity and accuracy. Finally, by calculating fidelity, we analyze the impact of four different types of noise(phase-damping, amplitude-damping, phase-flip and bit-flip) in this protocol.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 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
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
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
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
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
To increase the interoperability and privacy of digital asset transactions in multiparty cross-chain scenarios,Chen et al.proposed a cross-chain protocol based on multi-signatures and adaptor signatures that does not ...To increase the interoperability and privacy of digital asset transactions in multiparty cross-chain scenarios,Chen et al.proposed a cross-chain protocol based on multi-signatures and adaptor signatures that does not rely on smart contracts but instead depends on underlying scripts and signatures.However,since the protocol was designed without considering concurrent execution scenarios,it may still be vulnerable to certain types of attacks,posing potential security risks in practical applications.Therefore,this paper first presents an ROS attack against Chen et al.’s scheme,in which ROS attack was originally proposed by Benhamouda et al.in 2022 against the Schnorr-type threshold and multi-signatures and our attack exploits the random numbers generated by users in the offline-tolerant mechanism.By using a system of equations construction method,it is possible to forge valid signatures for arbitrary messages.Subsequently,the existing Chen et al.’s scheme is improved by establishing a nonlinear dependency between the random number and the message,without introducing additional interaction rounds or random parameters.This improvement eliminates the solvability of the linear system of equations in the ROS attack,thereby defending against this type of attack.Furthermore,security definitions and proofs are provided,detailing the complete properties of the improved adaptor signature scheme.Therefore,the proposed scheme in this paper enhances the theoretical security strength while maintaining the functionality and efficiency of Chen et al.’s scheme,and hence has more effective practicality.展开更多
Quantum dialogue(QD)realizes the real-time secure bidirectional quantum communication.Measurement-deviceindependent(MDI)QD can resist all possible attacks focusing on the imperfect measurement devices and enhance QD’...Quantum dialogue(QD)realizes the real-time secure bidirectional quantum communication.Measurement-deviceindependent(MDI)QD can resist all possible attacks focusing on the imperfect measurement devices and enhance QD’s practical security.However,in practical applications,any secure communication requires identity authentication as a prerequisite.In this paper,we propose an MDI QD protocol with bidirectional identity authentication.The practical communication parties can first authenticate the identity of each other simultaneously before the message exchange.In theory,our MDI QD protocol has unconditional security and the communication parties can exchange 1.5 bits of messages in each communication round with linear optical Bell state measurement.We numerically simulate the secrecy message capacity of our MDI QD protocol.Our protocol has two advantages.First,it can effectively resist the impersonation attack and enhance MDI QD’s practical security.Second,it does not require keys to assist the message exchange and has relatively high efficiency.Our protocol has application potential in the future quantum communication field.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.
基金the National Social Science Foundation of China(No.11BGJ013)
文摘This paper explores the effect of informed trading, heterogeneity investment and liquidity shocks on the valuation of credit default swaps(CDSs). Under the condition of asymmetric information, the informed trading plays an important role in the valuation of CDS. Instruction order flow has a significant influence on CDS price.And the scope of influence changes in accordance with different time interval, company status and the size of bid-ask spread. Heterogeneity of investors seriously affects the market liquidity and subsequently affects the CDS price. The bigger heterogeneity of the investment philosophy, investment habits, investment preference and so on is the bigger risk for market liquidity, and the higher price for CDS shall be. On the contrary, the conclusion is also consistent. The effectiveness of liquidity, whether it is before or after the financial crisis, dominates the fluctuation of CDS price. The premium of liquidity accounts for 36% to 50% of the CDS price.
基金supported by the National Natural Science Foundation of China(Nos.12101554,12301614),the Fundamental Research Funds for Zhejiang Provincial Universities(No.GB202103001)Zhejiang Provincial Natural Science Foundation of China(No.LQ22A010010)Ministry of Educational Social Science Foundation of China(No.21YJC880050).
文摘The effects of stochastic volatility,jump clustering,and regime switching are considered when pricing variance swaps.This study established a two-stage procedure that simplifies the derivation by first isolating the regime switching from other stochastic sources.Based on this,a novel probabilistic approach was employed,leading to pricing formulas with time-dependent and regime-switching parameters.The formulated solutions were easy to implement and differed from most existing results of variance swap pricing,where Fourier inversion or fast Fourier transform must be performed to obtain the final results,since they are completely analytical without involving integrations.The numerical results indicate that jump clustering and regime switching have a significant influence on variance swap prices.
文摘The use of credit default swaps （CDSs） has become increasingly popular over time. Between 2002 and 2007, gross notional amounts outstanding grew from below S2 trillion to nearly S60 trillion. The recent crisis has revealed several shortcomings in CDS market practices and structure. In addition, management of counterparty risk has proved insufficient, as has in some instances the settlement of contracts following a credit event. However, past problems should not distract from the potential benefits of these instruments. In particular, CDSs help complete markets, as they provide an effective means to hedge and trade credit risk. CDSs allow financial institutions to better manage their exposures, and investors benefit from an enhanced investment universe. The purpose of this paper is to present a complete and practical exposition of the CDS market and to explore how the development of the CDS market has played an important role in the credit risk markets. Currently, the CDS market is transforming into a more stable system. Various measures are being put in place to help enhance market transparency and mitigate operational and systemic risk. In particular, central counterparties have started to operate, which will eventually lead to an improved management of individual as well as system-wide risks.
基金supported by the National Social Science Fund of China under Grant No.14ATJ005Anhui Provincial Natural Science Foundation under Grant Nos.1308085MF93 and 1408085MKL84the National Natural Science Foundations of China under Grant No.11401556
文摘Pricing variance swaps under stochastic volatility has been an important subject pursued recently. Various approaches have been proposed, mainly due to the substantially increased trading activities of volatility-related derivatives in the past few years. In this note, the authors develop analytical method for pricing variance swaps under stochastic volatility with an Ornstein-Uhlenbeck(OU) process. By using Fourier transform algorithm, a closed-form solution for pricing variance swaps with stochastic volatility is obtained, and to give a comparison of fair strike value based on the discrete model, continuous model, and the Monte Carlo simulations.
文摘Each morning at Yangluo Port in Wuhan,Hubei Province,the all-electric cargo vessel Huahang Xinneng No.1 completes a battery swap in under 10 minutes before returning to service with nearly 8,000 kWh of power onboard。
文摘This study investigates the determinants that drive the volatility of the credit default swaps(CDS)of BRICIT(Brazil,Russia,India,China,Indonesia,and Turkey)nations as a proxy measure for sovereign risk.On the existence of cointegration,an unrestricted error correction model integrated with the autoregressive distributed lag(ARDL)model is applied to measure the short-run and long-run dynamics empirically.The study utilizes the Bayesian global vector autoregression methodology for cross-border spillover estimation.The study also suggests a strategy for policymakers for quadrant categorization to mitigate risk arising from cross-border spillover.The result of ARDL indicates that the global macroeconomic variables affect the BRICIT CDS more than domestic macroeconomic determinants,with Indian CDS being the most sensitive to Fed tapering.Notably,China’s CDS is the most sensitive to shocks,with the CDS volatility primarily driven by China’s geopolitical risk.Russian CDS is more sensitive to real effective exchange rates due to severe ruble depreciation than crude oil,despite Russia being a major oil exporter.The quadrant categorization indicates that the Indonesian stock market index is most interconnected with BRICIT CDS,while the Turkish long-term interest rates send the highest intensity spillover across BRICIT nations.
基金the National Natural Science Foundation of China(No.91632103)the Shanghai Education Commission Research and Innovation Program(No.2019-01-07-00-02-E00037)+2 种基金the Program of Shanghai Subject Chief Scientist(No.17XD1401700)the Higher Education Disciplinary Innovation Programthe“Eastern Scholar”Project。
文摘Working memory is a core cognitive function that supports goal-directed behavior and complex thought.We developed a spatial working memory and attention test on paired symbols(SWAPS)which has been proved to be a useful and valid tool for spatial working memory and attention studies in the fields of cognitive psychology,education,and psychiatry.The repeated administration of working memory capacity tests is common in clinical and research settings.Studies suggest that repeated cognitive tests may improve the performance scores also known as retest effects.The systematic investigation of retest effects in SWAPS is critical for interpreting scientific results,but it is still not fully developed.To address this,we recruited 77 college students aged 18–21 years and used SWAPS comprising 72 trials with different memory loads,learning time,and delay span.We repeated the test once a week for five weeks to investigate the retest effects of SWAPS.There were significant retest effects in the first two tests:the accuracy of the SWAPS tests significantly increased,and then stabilized.These findings provide useful information for researchers to appropriately use or interpret the repeated working memory tests.Further experiments are still needed to clarify the factors that mediate the retest effects,and find out the cognitive mechanism that influences the retest effects.
基金Project supported by the Open Fund of Anhui Key Laboratory of Mine Intelligent Equipment and Technology (Grant No. ZKSYS202204)the Talent Introduction Fund of Anhui University of Science and Technology (Grant No. 2021yjrc34)the Scientific Research Fund of Anhui Provincial Education Department (Grant No. KJ2020A0301)。
文摘Implementing quantum wireless multi-hop network communication is essential to improve the global quantum network system. In this paper, we employ eight-level GHZ states as quantum channels to realize multi-hop quantum communication, and utilize the logical relationship between the measurements of each node to derive the unitary operation performed by the end node. The hierarchical simultaneous entanglement switching(HSES) method is adopted, resulting in a significant reduction in the consumption of classical information compared to multi-hop quantum teleportation(QT)based on general simultaneous entanglement switching(SES). In addition, the proposed protocol is simulated on the IBM Quantum Experiment platform(IBM QE). Then, the data obtained from the experiment are analyzed using quantum state tomography, which verifies the protocol's good fidelity and accuracy. Finally, by calculating fidelity, we analyze the impact of four different types of noise(phase-damping, amplitude-damping, phase-flip and bit-flip) in this protocol.
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.
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 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.
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.
基金supported by the National Natural Science Foundation of China(61907042,61702570)the Beijing Natural Science Foundation(4194090)+1 种基金the Social Science Planning Project of Shandong Province(24CWYJ05)the Project of Research on the Course System of“Blockchain Technology and Applications”Based on the TuGraph Platform,Ant Group Co.,Ltd.
文摘To increase the interoperability and privacy of digital asset transactions in multiparty cross-chain scenarios,Chen et al.proposed a cross-chain protocol based on multi-signatures and adaptor signatures that does not rely on smart contracts but instead depends on underlying scripts and signatures.However,since the protocol was designed without considering concurrent execution scenarios,it may still be vulnerable to certain types of attacks,posing potential security risks in practical applications.Therefore,this paper first presents an ROS attack against Chen et al.’s scheme,in which ROS attack was originally proposed by Benhamouda et al.in 2022 against the Schnorr-type threshold and multi-signatures and our attack exploits the random numbers generated by users in the offline-tolerant mechanism.By using a system of equations construction method,it is possible to forge valid signatures for arbitrary messages.Subsequently,the existing Chen et al.’s scheme is improved by establishing a nonlinear dependency between the random number and the message,without introducing additional interaction rounds or random parameters.This improvement eliminates the solvability of the linear system of equations in the ROS attack,thereby defending against this type of attack.Furthermore,security definitions and proofs are provided,detailing the complete properties of the improved adaptor signature scheme.Therefore,the proposed scheme in this paper enhances the theoretical security strength while maintaining the functionality and efficiency of Chen et al.’s scheme,and hence has more effective practicality.
基金supported by the National Natural Science Foundation of China(Grant Nos.12175106 and 92365110)the Postgraduate Research and Practice Innovation Program of Jiangsu Province,China(Grant No.KYCX23-0987).
文摘Quantum dialogue(QD)realizes the real-time secure bidirectional quantum communication.Measurement-deviceindependent(MDI)QD can resist all possible attacks focusing on the imperfect measurement devices and enhance QD’s practical security.However,in practical applications,any secure communication requires identity authentication as a prerequisite.In this paper,we propose an MDI QD protocol with bidirectional identity authentication.The practical communication parties can first authenticate the identity of each other simultaneously before the message exchange.In theory,our MDI QD protocol has unconditional security and the communication parties can exchange 1.5 bits of messages in each communication round with linear optical Bell state measurement.We numerically simulate the secrecy message capacity of our MDI QD protocol.Our protocol has two advantages.First,it can effectively resist the impersonation attack and enhance MDI QD’s practical security.Second,it does not require keys to assist the message exchange and has relatively high efficiency.Our protocol has application potential in the future quantum communication field.
